* gettext.h --- external library
+binaries:
+- gnunet-service-xxx: service process (has listen socket)
+- gnunet-daemon-xxx: daemon process (no listen socket)
+- gnunet-helper-xxx[-yyy]: SUID helper for module xxx
+- gnunet-yyy: command-line tool for end-users
+- libgnunet_plugin_xxx_yyy.so: plugin for API xxx
+- libgnunetxxx.so: library for API xxx
+
+
configuration:
- paths (that are substituted in all filenames) are in PATHS (have as few as possible)
- globals for the daemon are in [gnunetd] (for now, have as few as possible!)
if MINGW
WINFLAGS = -Wl,--no-undefined -Wl,--export-all-symbols
- NATBIN = gnunet-nat-server gnunet-nat-client
- NATSERVER = gnunet-nat-server-windows.c
- NATCLIENT = gnunet-nat-client-windows.c
-else
- NATSERVER = gnunet-nat-server.c
- NATCLIENT = gnunet-nat-client.c
+ NATBIN = gnunet-helper-nat-server gnunet-helper-nat-client
+ NATSERVER = gnunet-helper-nat-server-windows.c
+ NATCLIENT = gnunet-helper-nat-client-windows.c
endif
if LINUX
-NATBIN = gnunet-nat-server gnunet-nat-client
+NATBIN = gnunet-helper-nat-server gnunet-helper-nat-client
+NATSERVER = gnunet-helper-nat-server.c
+NATCLIENT = gnunet-helper-nat-client.c
install-exec-hook:
- chown root:root $(bindir)/gnunet-nat-server $(bindir)/gnunet-nat-client $(bindir)/gnunet-transport-wlan-helper || true
- chmod u+s $(bindir)/gnunet-nat-server $(bindir)/gnunet-nat-client $(bindir)/gnunet-transport-wlan-helper || true
+ chown root:root $(bindir)/gnunet-helper-nat-server $(bindir)/gnunet-helper-nat-client || true
+ chmod u+s $(bindir)/gnunet-helper-nat-server $(bindir)/gnunet-helper-nat-client || true
else
install-exec-hook:
endif
bin_PROGRAMS = \
+ gnunet-nat-server \
$(NATBIN)
gnunet_nat_server_SOURCES = \
+ gnunet-nat-server.c
+gnunet_nat_server_LDADD = \
+ $(top_builddir)/src/util/libgnunetutil.la
+
+gnunet_helper_nat_server_SOURCES = \
$(NATSERVER)
-gnunet_nat_client_SOURCES = \
+gnunet_helper_nat_client_SOURCES = \
$(NATCLIENT)
-if MINGW
- WINFLAGS = -Wl,--no-undefined -Wl,--export-all-symbols
-endif
if USE_COVERAGE
AM_CFLAGS = -fprofile-arcs -ftest-coverage
--- /dev/null
+/*
+ This file is part of GNUnet.
+ (C) 2010 Christian Grothoff (and other contributing authors)
+
+ GNUnet is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 3, or (at your
+ option) any later version.
+
+ GNUnet is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GNUnet; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file src/nat/gnunet-helper-nat-client-windows.c
+ * @brief Tool to help bypass NATs using ICMP method; must run as
+ * administrator on W32
+ * This code is forx W32.
+ * @author Nathan Evans
+ *
+ * This program will send ONE ICMP message using RAW sockets
+ * to the IP address specified as the second argument. Since
+ * it uses RAW sockets, it must be installed SUID or run as 'root'.
+ * In order to keep the security risk of the resulting SUID binary
+ * minimal, the program ONLY opens the RAW socket with root
+ * privileges, then drops them and only then starts to process
+ * command line arguments. The code also does not link against
+ * any shared libraries (except libc) and is strictly minimal
+ * (except for checking for errors). The following list of people
+ * have reviewed this code and considered it safe since the last
+ * modification (if you reviewed it, please have your name added
+ * to the list):
+ *
+ * - Christian Grothoff
+ * - Nathan Evans
+ */
+#define _GNU_SOURCE
+
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <time.h>
+
+
+#define ICMP_ECHO 8
+#define IPDEFTTL 64
+#define ICMP_TIME_EXCEEDED 11
+
+/**
+ * Must match IP given in the server.
+ */
+#define DUMMY_IP "192.0.2.86"
+
+#define NAT_TRAV_PORT 22225
+
+/**
+ * IPv4 header.
+ */
+struct ip_header
+{
+
+ /**
+ * Version (4 bits) + Internet header length (4 bits)
+ */
+ uint8_t vers_ihl;
+
+ /**
+ * Type of service
+ */
+ uint8_t tos;
+
+ /**
+ * Total length
+ */
+ uint16_t pkt_len;
+
+ /**
+ * Identification
+ */
+ uint16_t id;
+
+ /**
+ * Flags (3 bits) + Fragment offset (13 bits)
+ */
+ uint16_t flags_frag_offset;
+
+ /**
+ * Time to live
+ */
+ uint8_t ttl;
+
+ /**
+ * Protocol
+ */
+ uint8_t proto;
+
+ /**
+ * Header checksum
+ */
+ uint16_t checksum;
+
+ /**
+ * Source address
+ */
+ uint32_t src_ip;
+
+ /**
+ * Destination address
+ */
+ uint32_t dst_ip;
+};
+
+
+/**
+ * Format of ICMP packet.
+ */
+struct icmp_ttl_exceeded_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t unused;
+
+ /* followed by original payload */
+};
+
+struct icmp_echo_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t reserved;
+};
+
+/**
+ * Beginning of UDP packet.
+ */
+struct udp_header
+{
+ uint16_t src_port;
+
+ uint16_t dst_port;
+
+ uint16_t length;
+
+ uint16_t crc;
+};
+
+
+/**
+ * Socket we use to send our ICMP packets.
+ */
+static SOCKET rawsock;
+
+/**
+ * Target "dummy" address.
+ */
+static struct in_addr dummy;
+
+/**
+ * Port we are listening on (communicated to the server).
+ */
+static uint16_t port;
+
+
+
+/**
+ * Convert IPv4 address from text to binary form.
+ *
+ * @param af address family
+ * @param cp the address to print
+ * @param buf where to write the address result
+ * @return 1 on success
+ */
+static int
+inet_pton (int af,
+ const char *cp,
+ struct in_addr *buf)
+{
+ buf->s_addr = inet_addr(cp);
+ if (buf->s_addr == INADDR_NONE)
+ {
+ fprintf(stderr,
+ "Error %d handling address %s",
+ WSAGetLastError(),
+ cp);
+ return 0;
+ }
+ return 1;
+}
+
+
+/**
+ * CRC-16 for IP/ICMP headers.
+ *
+ * @param data what to calculate the CRC over
+ * @param bytes number of bytes in data (must be multiple of 2)
+ * @return the CRC 16.
+ */
+static uint16_t
+calc_checksum(const uint16_t *data,
+ unsigned int bytes)
+{
+ uint32_t sum;
+ unsigned int i;
+
+ sum = 0;
+ for (i=0;i<bytes/2;i++)
+ sum += data[i];
+ sum = (sum & 0xffff) + (sum >> 16);
+ sum = htons(0xffff - sum);
+ return sum;
+}
+
+
+/**
+ * Send an ICMP message to the target.
+ *
+ * @param my_ip source address
+ * @param other target address
+ */
+static void
+send_icmp_udp (const struct in_addr *my_ip,
+ const struct in_addr *other)
+{
+ char packet[sizeof(struct ip_header) * 2 +
+ sizeof(struct icmp_ttl_exceeded_header) +
+ sizeof(struct udp_header)];
+ struct ip_header ip_pkt;
+ struct icmp_ttl_exceeded_header icmp_pkt;
+ struct udp_header udp_pkt;
+ struct sockaddr_in dst;
+ size_t off;
+ int err;
+
+ /* ip header: send to (known) ip address */
+ off = 0;
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons(sizeof (packet));
+ ip_pkt.id = htons(256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = 128;
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = my_ip->s_addr;
+ ip_pkt.dst_ip = other->s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy(&packet[off],
+ &ip_pkt,
+ sizeof(struct ip_header));
+ off += sizeof(struct ip_header);
+
+ icmp_pkt.type = ICMP_TIME_EXCEEDED;
+ icmp_pkt.code = 0;
+ icmp_pkt.checksum = 0;
+ icmp_pkt.unused = 0;
+ memcpy(&packet[off],
+ &icmp_pkt,
+ sizeof(struct icmp_ttl_exceeded_header));
+ off += sizeof(struct icmp_ttl_exceeded_header);
+
+ /* ip header of the presumably 'lost' udp packet */
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons(sizeof (struct ip_header) +
+ sizeof (struct udp_header));
+ ip_pkt.id = htons(0);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = 128;
+ ip_pkt.proto = IPPROTO_UDP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = other->s_addr;
+ ip_pkt.dst_ip = dummy.s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy(&packet[off],
+ &ip_pkt,
+ sizeof(struct ip_header));
+ off += sizeof(struct ip_header);
+
+ /* build UDP header */
+ udp_pkt.src_port = htons(NAT_TRAV_PORT);
+ udp_pkt.dst_port = htons(NAT_TRAV_PORT);
+ udp_pkt.length = htons (port);
+ udp_pkt.crc = 0;
+ memcpy(&packet[off],
+ &udp_pkt,
+ sizeof(struct udp_header));
+ off += sizeof(struct udp_header);
+
+ /* no go back to calculate ICMP packet checksum */
+ icmp_pkt.checksum = htons(calc_checksum((uint16_t*)&packet[off],
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct ip_header) +
+ sizeof (struct udp_header)));
+ memcpy (&packet[sizeof (struct ip_header)],
+ &icmp_pkt,
+ sizeof (struct icmp_ttl_exceeded_header));
+
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+ dst.sin_addr = *other;
+ err = sendto(rawsock,
+ packet,
+ sizeof (packet), 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+ if (err < 0)
+ {
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+ }
+ else if (sizeof (packet) != (size_t) err)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * Send an ICMP message to the target.
+ *
+ * @param my_ip source address
+ * @param other target address
+ */
+static void
+send_icmp (const struct in_addr *my_ip,
+ const struct in_addr *other)
+{
+ struct ip_header ip_pkt;
+ struct icmp_ttl_exceeded_header icmp_ttl;
+ struct icmp_echo_header icmp_echo;
+ struct sockaddr_in dst;
+ char packet[sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof(struct icmp_echo_header)];
+ size_t off;
+ int err;
+
+ /* ip header: send to (known) ip address */
+ off = 0;
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons (sizeof (packet));
+ ip_pkt.id = htons(256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = IPDEFTTL;
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = my_ip->s_addr;
+ ip_pkt.dst_ip = other->s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
+ off += sizeof (ip_pkt);
+
+ /* icmp reply: time exceeded */
+ icmp_ttl.type = ICMP_TIME_EXCEEDED;
+ icmp_ttl.code = 0;
+ icmp_ttl.checksum = 0;
+ icmp_ttl.unused = 0;
+ memcpy (&packet[off],
+ &icmp_ttl,
+ sizeof (struct icmp_ttl_exceeded_header));
+ off += sizeof (struct icmp_ttl_exceeded_header);
+
+ /* ip header of the presumably 'lost' udp packet */
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons(sizeof (struct ip_header) + sizeof (struct icmp_echo_header));
+ ip_pkt.id = htons (256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = 1; /* real TTL would be 1 on a time exceeded packet */
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.src_ip = other->s_addr;
+ ip_pkt.dst_ip = dummy.s_addr;
+ ip_pkt.checksum = 0;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+
+ icmp_echo.type = ICMP_ECHO;
+ icmp_echo.code = 0;
+ icmp_echo.reserved = htonl(port);
+ icmp_echo.checksum = 0;
+ icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
+ sizeof (struct icmp_echo_header)));
+ memcpy (&packet[off],
+ &icmp_echo,
+ sizeof(struct icmp_echo_header));
+
+ /* no go back to calculate ICMP packet checksum */
+ off = sizeof (struct ip_header);
+ icmp_ttl.checksum = htons(calc_checksum((uint16_t*) &packet[off],
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct ip_header) +
+ sizeof (struct icmp_echo_header)));
+ memcpy (&packet[off],
+ &icmp_ttl,
+ sizeof (struct icmp_ttl_exceeded_header));
+
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+ dst.sin_addr = *other;
+
+ err = sendto(rawsock,
+ packet,
+ sizeof (packet), 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+
+ if (err < 0)
+ {
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+ }
+ else if (sizeof (packet) != (size_t) err)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * Create an ICMP raw socket.
+ *
+ * @return INVALID_SOCKET on error
+ */
+static SOCKET
+make_raw_socket ()
+{
+ DWORD bOptVal = TRUE;
+ int bOptLen = sizeof(bOptVal);
+ SOCKET ret;
+
+ ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
+ if (INVALID_SOCKET == ret)
+ {
+ fprintf (stderr,
+ "Error opening RAW socket: %s\n",
+ strerror (errno));
+ return INVALID_SOCKET;
+ }
+ if (0 != setsockopt(ret, SOL_SOCKET, SO_BROADCAST, (char*)&bOptVal, bOptLen))
+ {
+ fprintf(stderr,
+ "Error setting SO_BROADCAST to ON: %s\n",
+ strerror (errno));
+ closesocket(rawsock);
+ return INVALID_SOCKET;
+ }
+
+ if (0 != setsockopt(ret, IPPROTO_IP, IP_HDRINCL, (char*)&bOptVal, bOptLen))
+ {
+ fprintf(stderr,
+ "Error setting IP_HDRINCL to ON: %s\n",
+ strerror (errno));
+ closesocket(rawsock);
+ return INVALID_SOCKET;
+ }
+ return ret;
+}
+
+
+int
+main (int argc, char *const *argv)
+{
+ struct in_addr external;
+ struct in_addr target;
+ WSADATA wsaData;
+
+ unsigned int p;
+
+ if (argc != 4)
+ {
+ fprintf (stderr,
+ "This program must be started with our IP, the targets external IP, and our port as arguments.\n");
+ return 1;
+ }
+ if ( (1 != inet_pton (AF_INET, argv[1], &external)) ||
+ (1 != inet_pton (AF_INET, argv[2], &target)) )
+ {
+ fprintf (stderr,
+ "Error parsing IPv4 address: %s\n",
+ strerror (errno));
+ return 1;
+ }
+ if ( (1 != sscanf (argv[3], "%u", &p) ) ||
+ (0 == p) ||
+ (0xFFFF < p) )
+ {
+ fprintf (stderr,
+ "Error parsing port value `%s'\n",
+ argv[3]);
+ return 1;
+ }
+ port = (uint16_t) p;
+
+ if (0 != WSAStartup (MAKEWORD (2, 1), &wsaData))
+ {
+ fprintf (stderr, "Failed to find Winsock 2.1 or better.\n");
+ return 2;
+ }
+ if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
+ {
+ fprintf (stderr,
+ "Internal error converting dummy IP to binary.\n");
+ return 2;
+ }
+ if (-1 == (rawsock = make_raw_socket()))
+ return 3;
+ send_icmp (&external,
+ &target);
+ send_icmp_udp (&external,
+ &target);
+ closesocket (rawsock);
+ WSACleanup ();
+ return 0;
+}
+
+/* end of gnunet-helper-nat-client-windows.c */
--- /dev/null
+/*
+ This file is part of GNUnet.
+ (C) 2010 Christian Grothoff (and other contributing authors)
+
+ GNUnet is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 3, or (at your
+ option) any later version.
+
+ GNUnet is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GNUnet; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file src/nat/gnunet-helper-nat-client.c
+ * @brief Tool to help bypass NATs using ICMP method; must run as root (SUID will do)
+ * This code will work under GNU/Linux only.
+ * @author Christian Grothoff
+ *
+ * This program will send ONE ICMP message using RAW sockets
+ * to the IP address specified as the second argument. Since
+ * it uses RAW sockets, it must be installed SUID or run as 'root'.
+ * In order to keep the security risk of the resulting SUID binary
+ * minimal, the program ONLY opens the RAW socket with root
+ * privileges, then drops them and only then starts to process
+ * command line arguments. The code also does not link against
+ * any shared libraries (except libc) and is strictly minimal
+ * (except for checking for errors). The following list of people
+ * have reviewed this code and considered it safe since the last
+ * modification (if you reviewed it, please have your name added
+ * to the list):
+ *
+ * - Christian Grothoff
+ * - Nathan Evans
+ * - Benjamin Kuperman (22 Aug 2010)
+ */
+#if HAVE_CONFIG_H
+/* Just needed for HAVE_SOCKADDR_IN_SIN_LEN test macro! */
+#include "gnunet_config.h"
+#else
+#define _GNU_SOURCE
+#endif
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/in.h>
+
+/**
+ * Must match IP given in the server.
+ */
+#define DUMMY_IP "192.0.2.86"
+
+#define NAT_TRAV_PORT 22225
+
+/**
+ * IPv4 header.
+ */
+struct ip_header
+{
+
+ /**
+ * Version (4 bits) + Internet header length (4 bits)
+ */
+ uint8_t vers_ihl;
+
+ /**
+ * Type of service
+ */
+ uint8_t tos;
+
+ /**
+ * Total length
+ */
+ uint16_t pkt_len;
+
+ /**
+ * Identification
+ */
+ uint16_t id;
+
+ /**
+ * Flags (3 bits) + Fragment offset (13 bits)
+ */
+ uint16_t flags_frag_offset;
+
+ /**
+ * Time to live
+ */
+ uint8_t ttl;
+
+ /**
+ * Protocol
+ */
+ uint8_t proto;
+
+ /**
+ * Header checksum
+ */
+ uint16_t checksum;
+
+ /**
+ * Source address
+ */
+ uint32_t src_ip;
+
+ /**
+ * Destination address
+ */
+ uint32_t dst_ip;
+};
+
+/**
+ * Format of ICMP packet.
+ */
+struct icmp_ttl_exceeded_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t unused;
+
+ /* followed by original payload */
+};
+
+struct icmp_echo_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t reserved;
+};
+
+/**
+ * Beginning of UDP packet.
+ */
+struct udp_header
+{
+ uint16_t src_port;
+
+ uint16_t dst_port;
+
+ uint16_t length;
+
+ uint16_t crc;
+};
+
+/**
+ * Socket we use to send our fake ICMP replies.
+ */
+static int rawsock;
+
+/**
+ * Target "dummy" address of the packet we pretend to respond to.
+ */
+static struct in_addr dummy;
+
+/**
+ * Our "source" port.
+ */
+static uint16_t port;
+
+
+/**
+ * CRC-16 for IP/ICMP headers.
+ *
+ * @param data what to calculate the CRC over
+ * @param bytes number of bytes in data (must be multiple of 2)
+ * @return the CRC 16.
+ */
+static uint16_t
+calc_checksum (const uint16_t *data,
+ unsigned int bytes)
+{
+ uint32_t sum;
+ unsigned int i;
+
+ sum = 0;
+ for (i=0;i<bytes/2;i++)
+ sum += data[i];
+ sum = (sum & 0xffff) + (sum >> 16);
+ sum = htons(0xffff - sum);
+ return sum;
+}
+
+
+/**
+ * Send an ICMP message to the target.
+ *
+ * @param my_ip source address
+ * @param other target address
+ */
+static void
+send_icmp_udp (const struct in_addr *my_ip,
+ const struct in_addr *other)
+{
+ char packet[sizeof(struct ip_header) * 2 +
+ sizeof(struct icmp_ttl_exceeded_header) +
+ sizeof(struct udp_header)];
+ struct ip_header ip_pkt;
+ struct icmp_ttl_exceeded_header icmp_pkt;
+ struct udp_header udp_pkt;
+ struct sockaddr_in dst;
+ size_t off;
+ int err;
+
+ /* ip header: send to (known) ip address */
+ off = 0;
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons (sizeof (packet));
+ ip_pkt.id = htons(256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = 128;
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = my_ip->s_addr;
+ ip_pkt.dst_ip = other->s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy(&packet[off],
+ &ip_pkt,
+ sizeof(struct ip_header));
+ off += sizeof(struct ip_header);
+
+ icmp_pkt.type = ICMP_TIME_EXCEEDED;
+ icmp_pkt.code = 0;
+ icmp_pkt.checksum = 0;
+ icmp_pkt.unused = 0;
+ memcpy(&packet[off],
+ &icmp_pkt,
+ sizeof(struct icmp_ttl_exceeded_header));
+ off += sizeof(struct icmp_ttl_exceeded_header);
+
+ /* ip header of the presumably 'lost' udp packet */
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons(sizeof (struct ip_header) +
+ sizeof (struct udp_header));
+ ip_pkt.id = htons(0);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = 128;
+ ip_pkt.proto = IPPROTO_UDP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = other->s_addr;
+ ip_pkt.dst_ip = dummy.s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy(&packet[off],
+ &ip_pkt,
+ sizeof(struct ip_header));
+ off += sizeof(struct ip_header);
+
+ /* build UDP header */
+ udp_pkt.src_port = htons(NAT_TRAV_PORT);
+ udp_pkt.dst_port = htons(NAT_TRAV_PORT);
+ udp_pkt.length = htons (port);
+ udp_pkt.crc = 0;
+ memcpy(&packet[off],
+ &udp_pkt,
+ sizeof(struct udp_header));
+ off += sizeof(struct udp_header);
+
+ /* set ICMP checksum */
+ icmp_pkt.checksum = htons(calc_checksum((uint16_t*)&packet[sizeof(struct ip_header)],
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct ip_header) +
+ sizeof (struct udp_header)));
+ memcpy (&packet[sizeof(struct ip_header)],
+ &icmp_pkt,
+ sizeof (struct icmp_ttl_exceeded_header));
+
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+#if HAVE_SOCKADDR_IN_SIN_LEN
+ dst.sin_len = sizeof (struct sockaddr_in);
+#endif
+ dst.sin_addr = *other;
+ err = sendto(rawsock,
+ packet,
+ sizeof (packet), 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+ if (err < 0)
+ {
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+ }
+ else if (sizeof (packet) != (size_t) err)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * Send an ICMP message to the target.
+ *
+ * @param my_ip source address
+ * @param other target address
+ */
+static void
+send_icmp (const struct in_addr *my_ip,
+ const struct in_addr *other)
+{
+ struct ip_header ip_pkt;
+ struct icmp_ttl_exceeded_header icmp_ttl;
+ struct icmp_echo_header icmp_echo;
+ struct sockaddr_in dst;
+ char packet[sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct icmp_echo_header)];
+ size_t off;
+ int err;
+
+ /* ip header: send to (known) ip address */
+ off = 0;
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons (sizeof (packet));
+ ip_pkt.id = htons (256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = IPDEFTTL;
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = my_ip->s_addr;
+ ip_pkt.dst_ip = other->s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
+ off = sizeof (ip_pkt);
+
+ /* icmp reply: time exceeded */
+ icmp_ttl.type = ICMP_TIME_EXCEEDED;
+ icmp_ttl.code = 0;
+ icmp_ttl.checksum = 0;
+ icmp_ttl.unused = 0;
+ memcpy (&packet[off],
+ &icmp_ttl,
+ sizeof (struct icmp_ttl_exceeded_header));
+ off += sizeof (struct icmp_ttl_exceeded_header);
+
+ /* ip header of the presumably 'lost' udp packet */
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons (sizeof (struct ip_header) + sizeof (struct icmp_echo_header));
+ ip_pkt.id = htons (256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = 1; /* real TTL would be 1 on a time exceeded packet */
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.src_ip = other->s_addr;
+ ip_pkt.dst_ip = dummy.s_addr;
+ ip_pkt.checksum = 0;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+
+ icmp_echo.type = ICMP_ECHO;
+ icmp_echo.code = 0;
+ icmp_echo.reserved = htonl (port);
+ icmp_echo.checksum = 0;
+ icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
+ sizeof (struct icmp_echo_header)));
+ memcpy (&packet[off],
+ &icmp_echo,
+ sizeof(struct icmp_echo_header));
+
+ /* no go back to calculate ICMP packet checksum */
+ off = sizeof (struct ip_header);
+ icmp_ttl.checksum = htons(calc_checksum((uint16_t*) &packet[off],
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct ip_header) +
+ sizeof (struct icmp_echo_header)));
+ memcpy (&packet[off],
+ &icmp_ttl,
+ sizeof (struct icmp_ttl_exceeded_header));
+
+ /* prepare for transmission */
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+#if HAVE_SOCKADDR_IN_SIN_LEN
+ dst.sin_len = sizeof (struct sockaddr_in);
+#endif
+ dst.sin_addr = *other;
+ err = sendto(rawsock,
+ packet,
+ sizeof (packet), 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+ if (err < 0)
+ {
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+ }
+ else if (sizeof (packet) != (size_t) err)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * Create an ICMP raw socket for writing.
+ *
+ * @return -1 on error
+ */
+static int
+make_raw_socket ()
+{
+ const int one = 1;
+ int ret;
+
+ ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
+ if (-1 == ret)
+ {
+ fprintf (stderr,
+ "Error opening RAW socket: %s\n",
+ strerror (errno));
+ return -1;
+ }
+ if (0 != setsockopt(ret, SOL_SOCKET, SO_BROADCAST,
+ (char *)&one, sizeof(one)))
+ {
+ fprintf(stderr,
+ "setsockopt failed: %s\n",
+ strerror (errno));
+ close (ret);
+ return -1;
+ }
+ if (0 != setsockopt(ret, IPPROTO_IP, IP_HDRINCL,
+ (char *)&one, sizeof(one)))
+ {
+ fprintf(stderr,
+ "setsockopt failed: %s\n",
+ strerror (errno));
+ close (ret);
+ return -1;
+ }
+ return ret;
+}
+
+
+int
+main (int argc, char *const *argv)
+{
+ struct in_addr external;
+ struct in_addr target;
+ uid_t uid;
+ unsigned int p;
+
+ if (4 != argc)
+ {
+ fprintf (stderr,
+ "This program must be started with our IP, the targets external IP, and our port as arguments.\n");
+ return 1;
+ }
+ if ( (1 != inet_pton (AF_INET, argv[1], &external)) ||
+ (1 != inet_pton (AF_INET, argv[2], &target)) )
+ {
+ fprintf (stderr,
+ "Error parsing IPv4 address: %s\n",
+ strerror (errno));
+ return 1;
+ }
+ if ( (1 != sscanf (argv[3], "%u", &p) ) ||
+ (0 == p) ||
+ (0xFFFF < p) )
+ {
+ fprintf (stderr,
+ "Error parsing port value `%s'\n",
+ argv[3]);
+ return 1;
+ }
+ port = (uint16_t) p;
+ if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
+ {
+ fprintf (stderr,
+ "Internal error converting dummy IP to binary.\n");
+ return 2;
+ }
+ if (-1 == (rawsock = make_raw_socket()))
+ return 2;
+ uid = getuid ();
+ if (0 != setresuid (uid, uid, uid))
+ {
+ fprintf (stderr,
+ "Failed to setresuid: %s\n",
+ strerror (errno));
+ /* not critical, continue anyway */
+ }
+ send_icmp (&external,
+ &target);
+ send_icmp_udp (&external,
+ &target);
+ close (rawsock);
+ return 0;
+}
+
+/* end of gnunet-helper-nat-client.c */
--- /dev/null
+/*
+ This file is part of GNUnet.
+ (C) 2010 Christian Grothoff (and other contributing authors)
+
+ GNUnet is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 3, or (at your
+ option) any later version.
+
+ GNUnet is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GNUnet; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file src/nat/gnunet-helper-nat-server-windows.c
+ * @brief Windows tool to help bypass NATs using ICMP method
+ * This code will work under W32 only
+ * @author Christian Grothoff
+ *
+ * This program will send ONE ICMP message every 500 ms RAW sockets
+ * to a DUMMY IP address and also listens for ICMP replies. Since
+ * it uses RAW sockets, it must be run as an administrative user.
+ * In order to keep the security risk of the resulting binary
+ * minimal, the program ONLY opens the two RAW sockets with administrative
+ * privileges, then drops them and only then starts to process
+ * command line arguments. The code also does not link against
+ * any shared libraries (except libc) and is strictly minimal
+ * (except for checking for errors). The following list of people
+ * have reviewed this code and considered it safe since the last
+ * modification (if you reviewed it, please have your name added
+ * to the list):
+ *
+ * - Nathan Evans
+ * - Christian Grothoff
+ */
+#define _GNU_SOURCE
+
+
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <time.h>
+
+/**
+ * Should we print some debug output?
+ */
+#define VERBOSE 0
+
+/**
+ * Must match IP given in the client.
+ */
+#define DUMMY_IP "192.0.2.86"
+
+/**
+ * Default Port
+ */
+#define NAT_TRAV_PORT 22225
+
+/**
+ * TTL to use for our outgoing messages.
+ */
+#define IPDEFTTL 64
+
+#define ICMP_ECHO 8
+
+#define ICMP_TIME_EXCEEDED 11
+
+/**
+ * How often do we send our ICMP messages to receive replies?
+ */
+#define ICMP_SEND_FREQUENCY_MS 500
+
+/**
+ * IPv4 header.
+ */
+struct ip_header
+{
+
+ /**
+ * Version (4 bits) + Internet header length (4 bits)
+ */
+ uint8_t vers_ihl;
+
+ /**
+ * Type of service
+ */
+ uint8_t tos;
+
+ /**
+ * Total length
+ */
+ uint16_t pkt_len;
+
+ /**
+ * Identification
+ */
+ uint16_t id;
+
+ /**
+ * Flags (3 bits) + Fragment offset (13 bits)
+ */
+ uint16_t flags_frag_offset;
+
+ /**
+ * Time to live
+ */
+ uint8_t ttl;
+
+ /**
+ * Protocol
+ */
+ uint8_t proto;
+
+ /**
+ * Header checksum
+ */
+ uint16_t checksum;
+
+ /**
+ * Source address
+ */
+ uint32_t src_ip;
+
+ /**
+ * Destination address
+ */
+ uint32_t dst_ip;
+};
+
+/**
+ * Format of ICMP packet.
+ */
+struct icmp_ttl_exceeded_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t unused;
+
+ /* followed by original payload */
+};
+
+struct icmp_echo_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t reserved;
+};
+
+/**
+ * Beginning of UDP packet.
+ */
+struct udp_header
+{
+ uint16_t src_port;
+
+ uint16_t dst_port;
+
+ uint16_t length;
+
+ uint16_t crc;
+};
+
+/**
+ * Socket we use to receive "fake" ICMP replies.
+ */
+static SOCKET icmpsock;
+
+/**
+ * Socket we use to send our ICMP requests.
+ */
+static SOCKET rawsock;
+
+/**
+ * Socket we use to send our UDP requests.
+ */
+static SOCKET udpsock;
+
+/**
+ * Target "dummy" address.
+ */
+static struct in_addr dummy;
+
+
+/**
+ * CRC-16 for IP/ICMP headers.
+ *
+ * @param data what to calculate the CRC over
+ * @param bytes number of bytes in data (must be multiple of 2)
+ * @return the CRC 16.
+ */
+static uint16_t
+calc_checksum(const uint16_t *data,
+ unsigned int bytes)
+{
+ uint32_t sum;
+ unsigned int i;
+
+ sum = 0;
+ for (i=0;i<bytes/2;i++)
+ sum += data[i];
+ sum = (sum & 0xffff) + (sum >> 16);
+ sum = htons(0xffff - sum);
+ return sum;
+}
+
+
+/**
+ * Convert IPv4 address from text to binary form.
+ *
+ * @param af address family
+ * @param cp the address to print
+ * @param buf where to write the address result
+ * @return 1 on success
+ */
+static int
+inet_pton (int af,
+ const char *cp,
+ struct in_addr *buf)
+{
+ buf->s_addr = inet_addr(cp);
+ if (buf->s_addr == INADDR_NONE)
+ {
+ fprintf(stderr,
+ "Error %d handling address %s",
+ WSAGetLastError(),
+ cp);
+ return 0;
+ }
+ return 1;
+}
+
+
+/**
+ * Send an ICMP message to the dummy IP.
+ *
+ * @param my_ip source address (our ip address)
+ */
+static void
+send_icmp_echo (const struct in_addr *my_ip)
+{
+ char packet[sizeof (struct ip_header) + sizeof (struct icmp_echo_header)];
+ struct icmp_echo_header icmp_echo;
+ struct ip_header ip_pkt;
+ struct sockaddr_in dst;
+ size_t off;
+ int err;
+
+ off = 0;
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons (sizeof (packet));
+ ip_pkt.id = htons (256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = IPDEFTTL;
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = my_ip->s_addr;
+ ip_pkt.dst_ip = dummy.s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+
+ icmp_echo.type = ICMP_ECHO;
+ icmp_echo.code = 0;
+ icmp_echo.reserved = 0;
+ icmp_echo.checksum = 0;
+ icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
+ sizeof (struct icmp_echo_header)));
+ memcpy (&packet[off],
+ &icmp_echo,
+ sizeof (struct icmp_echo_header));
+ off += sizeof (struct icmp_echo_header);
+
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+ dst.sin_addr = dummy;
+ err = sendto(rawsock,
+ packet, off, 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+ if (err < 0)
+ {
+#if VERBOSE
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+#endif
+ }
+ else if (err != off)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * Send a UDP message to the dummy IP.
+ */
+static void
+send_udp ()
+{
+ struct sockaddr_in dst;
+ ssize_t err;
+
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+ dst.sin_addr = dummy;
+ dst.sin_port = htons (NAT_TRAV_PORT);
+ err = sendto(udpsock,
+ NULL, 0, 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+ if (err < 0)
+ {
+#if VERBOSE
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+#endif
+ }
+ else if (0 != err)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * We've received an ICMP response. Process it.
+ */
+static void
+process_icmp_response ()
+{
+ char buf[65536];
+ ssize_t have;
+ struct in_addr source_ip;
+ struct ip_header ip_pkt;
+ struct icmp_ttl_exceeded_header icmp_ttl;
+ struct icmp_echo_header icmp_echo;
+ struct udp_header udp_pkt;
+ size_t off;
+ uint16_t port;
+ DWORD ssize;
+
+ have = read (icmpsock, buf, sizeof (buf));
+ if (have == -1)
+ {
+ fprintf (stderr,
+ "Error reading raw socket: %s\n",
+ strerror (errno));
+ return;
+ }
+#if VERBOSE
+ fprintf (stderr,
+ "Received message of %u bytes\n",
+ (unsigned int) have);
+#endif
+ if (have < (ssize_t) (sizeof (struct ip_header) + sizeof (struct icmp_ttl_exceeded_header) + sizeof (struct ip_header)))
+ {
+ /* malformed */
+ return;
+ }
+ off = 0;
+ memcpy (&ip_pkt,
+ &buf[off],
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+ memcpy(&source_ip,
+ &ip_pkt.src_ip,
+ sizeof (source_ip));
+ memcpy (&icmp_ttl,
+ &buf[off],
+ sizeof (struct icmp_ttl_exceeded_header));
+ off += sizeof (struct icmp_ttl_exceeded_header);
+ if ( (ICMP_TIME_EXCEEDED != icmp_ttl.type) ||
+ (0 != icmp_ttl.code) )
+ {
+ /* different type than what we want */
+ return;
+ }
+ /* skip 2nd IP header */
+ memcpy (&ip_pkt,
+ &buf[off],
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+
+ switch (ip_pkt.proto)
+ {
+ case IPPROTO_ICMP:
+ if (have != (sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct icmp_echo_header)) )
+ {
+ /* malformed */
+ return;
+ }
+ /* grab ICMP ECHO content */
+ memcpy (&icmp_echo,
+ &buf[off],
+ sizeof (struct icmp_echo_header));
+ port = (uint16_t) ntohl (icmp_echo.reserved);
+ break;
+ case IPPROTO_UDP:
+ if (have != (sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct udp_header)) )
+ {
+ /* malformed */
+ return;
+ }
+ /* grab UDP content */
+ memcpy (&udp_pkt,
+ &buf[off],
+ sizeof (struct udp_header));
+ port = ntohs (udp_pkt.length);
+ break;
+ default:
+ /* different type than what we want */
+ return;
+ }
+
+ ssize = sizeof(buf);
+ WSAAddressToString((LPSOCKADDR)&source_ip,
+ sizeof(source_ip),
+ NULL,
+ buf,
+ &ssize);
+ if (port == 0)
+ fprintf (stdout,
+ "%s\n",
+ buf);
+ else
+ fprintf (stdout,
+ "%s:%u\n",
+ buf,
+ (unsigned int) port);
+ fflush (stdout);
+}
+
+
+/**
+ * Create an ICMP raw socket for reading.
+ *
+ * @return INVALID_SOCKET on error
+ */
+static SOCKET
+make_icmp_socket ()
+{
+ SOCKET ret;
+
+ ret = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP);
+ if (INVALID_SOCKET == ret)
+ {
+ fprintf (stderr,
+ "Error opening RAW socket: %s\n",
+ strerror (errno));
+ return INVALID_SOCKET;
+ }
+ return ret;
+}
+
+
+/**
+ * Create an ICMP raw socket for writing.
+ *
+ * @return INVALID_SOCKET on error
+ */
+static SOCKET
+make_raw_socket ()
+{
+ DWORD bOptVal = TRUE;
+ int bOptLen = sizeof(bOptVal);
+
+ rawsock = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP);
+ if (INVALID_SOCKET == rawsock)
+ {
+ fprintf (stderr,
+ "Error opening RAW socket: %s\n",
+ strerror (errno));
+ return INVALID_SOCKET;
+ }
+
+ if (0 != setsockopt(rawsock,
+ SOL_SOCKET,
+ SO_BROADCAST,
+ (char*)&bOptVal, bOptLen))
+ {
+ fprintf(stderr,
+ "Error setting SO_BROADCAST to ON: %s\n",
+ strerror (errno));
+ closesocket(rawsock);
+ return INVALID_SOCKET;
+ }
+ if (0 != setsockopt(rawsock,
+ IPPROTO_IP,
+ IP_HDRINCL,
+ (char*)&bOptVal, bOptLen))
+ {
+ fprintf(stderr,
+ "Error setting IP_HDRINCL to ON: %s\n",
+ strerror (errno));
+ closesocket(rawsock);
+ return INVALID_SOCKET;
+ }
+ return rawsock;
+}
+
+
+/**
+ * Create a UDP socket for writing.
+ *
+ * @param my_ip source address (our ip address)
+ * @return INVALID_SOCKET on error
+ */
+static SOCKET
+make_udp_socket (const struct in_addr *my_ip)
+{
+ SOCKET ret;
+ struct sockaddr_in addr;
+
+ ret = socket (AF_INET, SOCK_DGRAM, 0);
+ if (INVALID_SOCKET == ret)
+ {
+ fprintf (stderr,
+ "Error opening UDP socket: %s\n",
+ strerror (errno));
+ return INVALID_SOCKET;
+ }
+ memset (&addr, 0, sizeof (addr));
+ addr.sin_family = AF_INET;
+ addr.sin_addr = *my_ip;
+ addr.sin_port = htons (NAT_TRAV_PORT);
+ if (0 != bind (ret,
+ (struct sockaddr *)&addr,
+ sizeof(addr)))
+ {
+ fprintf (stderr,
+ "Error binding UDP socket to port %u: %s\n",
+ NAT_TRAV_PORT,
+ strerror (errno));
+ /* likely problematic, but not certain, try to continue */
+ }
+ return ret;
+}
+
+
+int
+main (int argc,
+ char *const *argv)
+{
+ struct in_addr external;
+ fd_set rs;
+ struct timeval tv;
+ WSADATA wsaData;
+ unsigned int alt;
+
+ alt = 0;
+ if (2 != argc)
+ {
+ fprintf (stderr,
+ "This program must be started with our (internal NAT) IP as the only argument.\n");
+ return 1;
+ }
+ if (1 != inet_pton (AF_INET, argv[1], &external))
+ {
+ fprintf (stderr,
+ "Error parsing IPv4 address: %s, error %s\n",
+ argv[1], strerror (errno));
+ return 1;
+ }
+ if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
+ {
+ fprintf (stderr,
+ "Internal error converting dummy IP to binary.\n");
+ return 2;
+ }
+ if (WSAStartup (MAKEWORD (2, 1), &wsaData) != 0)
+ {
+ fprintf (stderr, "Failed to find Winsock 2.1 or better.\n");
+ return 2;
+ }
+ if (INVALID_SOCKET == (icmpsock = make_icmp_socket()))
+ {
+ return 3;
+ }
+ if (INVALID_SOCKET == (make_raw_socket()))
+ {
+ closesocket (icmpsock);
+ return 3;
+ }
+ if (INVALID_SOCKET == (udpsock = make_udp_socket(&external)))
+ {
+ closesocket (icmpsock);
+ closesocket (rawsock);
+ return 3;
+ }
+ while (1)
+ {
+ FD_ZERO (&rs);
+ FD_SET (icmpsock, &rs);
+ tv.tv_sec = 0;
+ tv.tv_usec = ICMP_SEND_FREQUENCY_MS * 1000;
+ if (-1 == select (icmpsock + 1, &rs, NULL, NULL, &tv))
+ {
+ if (errno == EINTR)
+ continue;
+ fprintf (stderr,
+ "select failed: %s\n",
+ strerror (errno));
+ break;
+ }
+ if (FD_ISSET (icmpsock, &rs))
+ process_icmp_response ();
+ if (0 == (++alt % 2))
+ send_icmp_echo (&external);
+ else
+ send_udp ();
+ }
+ /* select failed (internal error or OS out of resources) */
+ closesocket(icmpsock);
+ closesocket(rawsock);
+ closesocket(udpsock);
+ WSACleanup ();
+ return 4;
+}
+
+
+/* end of gnunet-helper-nat-server-windows.c */
--- /dev/null
+/*
+ This file is part of GNUnet.
+ (C) 2010 Christian Grothoff (and other contributing authors)
+
+ GNUnet is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 3, or (at your
+ option) any later version.
+
+ GNUnet is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GNUnet; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file src/nat/gnunet-helper-nat-server.c
+ * @brief Tool to help bypass NATs using ICMP method; must run as root (SUID will do)
+ * This code will work under GNU/Linux only (or maybe BSDs, but never W32)
+ * @author Christian Grothoff
+ *
+ * This program will send ONE ICMP message every 500 ms RAW sockets
+ * to a DUMMY IP address and also listens for ICMP replies. Since
+ * it uses RAW sockets, it must be installed SUID or run as 'root'.
+ * In order to keep the security risk of the resulting SUID binary
+ * minimal, the program ONLY opens the two RAW sockets with root
+ * privileges, then drops them and only then starts to process
+ * command line arguments. The code also does not link against
+ * any shared libraries (except libc) and is strictly minimal
+ * (except for checking for errors). The following list of people
+ * have reviewed this code and considered it safe since the last
+ * modification (if you reviewed it, please have your name added
+ * to the list):
+ *
+ * - Christian Grothoff
+ * - Nathan Evans
+ * - Benjamin Kuperman (22 Aug 2010)
+ */
+#if HAVE_CONFIG_H
+/* Just needed for HAVE_SOCKADDR_IN_SIN_LEN test macro! */
+#include "gnunet_config.h"
+#else
+#define _GNU_SOURCE
+#endif
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <time.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/in.h>
+
+/**
+ * Should we print some debug output?
+ */
+#define VERBOSE 0
+
+/**
+ * Must match IP given in the client.
+ */
+#define DUMMY_IP "192.0.2.86"
+
+/**
+ * Port for UDP
+ */
+#define NAT_TRAV_PORT 22225
+
+/**
+ * How often do we send our ICMP messages to receive replies?
+ */
+#define ICMP_SEND_FREQUENCY_MS 500
+
+/**
+ * IPv4 header.
+ */
+struct ip_header
+{
+
+ /**
+ * Version (4 bits) + Internet header length (4 bits)
+ */
+ uint8_t vers_ihl;
+
+ /**
+ * Type of service
+ */
+ uint8_t tos;
+
+ /**
+ * Total length
+ */
+ uint16_t pkt_len;
+
+ /**
+ * Identification
+ */
+ uint16_t id;
+
+ /**
+ * Flags (3 bits) + Fragment offset (13 bits)
+ */
+ uint16_t flags_frag_offset;
+
+ /**
+ * Time to live
+ */
+ uint8_t ttl;
+
+ /**
+ * Protocol
+ */
+ uint8_t proto;
+
+ /**
+ * Header checksum
+ */
+ uint16_t checksum;
+
+ /**
+ * Source address
+ */
+ uint32_t src_ip;
+
+ /**
+ * Destination address
+ */
+ uint32_t dst_ip;
+};
+
+/**
+ * Format of ICMP packet.
+ */
+struct icmp_ttl_exceeded_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t unused;
+
+ /* followed by original payload */
+};
+
+struct icmp_echo_header
+{
+ uint8_t type;
+
+ uint8_t code;
+
+ uint16_t checksum;
+
+ uint32_t reserved;
+};
+
+
+/**
+ * Beginning of UDP packet.
+ */
+struct udp_header
+{
+ uint16_t src_port;
+
+ uint16_t dst_port;
+
+ uint16_t length;
+
+ uint16_t crc;
+};
+
+/**
+ * Socket we use to receive "fake" ICMP replies.
+ */
+static int icmpsock;
+
+/**
+ * Socket we use to send our ICMP requests.
+ */
+static int rawsock;
+
+/**
+ * Socket we use to send our UDP requests.
+ */
+static int udpsock;
+
+/**
+ * Target "dummy" address.
+ */
+static struct in_addr dummy;
+
+
+/**
+ * CRC-16 for IP/ICMP headers.
+ *
+ * @param data what to calculate the CRC over
+ * @param bytes number of bytes in data (must be multiple of 2)
+ * @return the CRC 16.
+ */
+static uint16_t
+calc_checksum(const uint16_t *data,
+ unsigned int bytes)
+{
+ uint32_t sum;
+ unsigned int i;
+
+ sum = 0;
+ for (i=0;i<bytes/2;i++)
+ sum += data[i];
+ sum = (sum & 0xffff) + (sum >> 16);
+ sum = htons(0xffff - sum);
+ return sum;
+}
+
+
+/**
+ * Send an ICMP message to the dummy IP.
+ *
+ * @param my_ip source address (our ip address)
+ */
+static void
+send_icmp_echo (const struct in_addr *my_ip)
+{
+ char packet[sizeof (struct ip_header) + sizeof (struct icmp_echo_header)];
+ struct icmp_echo_header icmp_echo;
+ struct ip_header ip_pkt;
+ struct sockaddr_in dst;
+ size_t off;
+ int err;
+
+ off = 0;
+ ip_pkt.vers_ihl = 0x45;
+ ip_pkt.tos = 0;
+ ip_pkt.pkt_len = htons (sizeof (packet));
+ ip_pkt.id = htons (256);
+ ip_pkt.flags_frag_offset = 0;
+ ip_pkt.ttl = IPDEFTTL;
+ ip_pkt.proto = IPPROTO_ICMP;
+ ip_pkt.checksum = 0;
+ ip_pkt.src_ip = my_ip->s_addr;
+ ip_pkt.dst_ip = dummy.s_addr;
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
+ sizeof (struct ip_header)));
+ memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+
+ icmp_echo.type = ICMP_ECHO;
+ icmp_echo.code = 0;
+ icmp_echo.checksum = 0;
+ icmp_echo.reserved = 0;
+ icmp_echo.checksum = htons(calc_checksum((uint16_t*)&icmp_echo,
+ sizeof (struct icmp_echo_header)));
+ memcpy (&packet[off],
+ &icmp_echo,
+ sizeof (struct icmp_echo_header));
+ off += sizeof (struct icmp_echo_header);
+
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+#if HAVE_SOCKADDR_IN_SIN_LEN
+ dst.sin_len = sizeof (struct sockaddr_in);
+#endif
+ dst.sin_addr = dummy;
+ err = sendto(rawsock,
+ packet, off, 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+ if (err < 0)
+ {
+#if VERBOSE
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+#endif
+ }
+ else if (sizeof (packet) != err)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * Send a UDP message to the dummy IP.
+ */
+static void
+send_udp ()
+{
+ struct sockaddr_in dst;
+ ssize_t err;
+
+ memset (&dst, 0, sizeof (dst));
+ dst.sin_family = AF_INET;
+#if HAVE_SOCKADDR_IN_SIN_LEN
+ dst.sin_len = sizeof (struct sockaddr_in);
+#endif
+ dst.sin_addr = dummy;
+ dst.sin_port = htons (NAT_TRAV_PORT);
+ err = sendto(udpsock,
+ NULL, 0, 0,
+ (struct sockaddr*)&dst,
+ sizeof(dst));
+ if (err < 0)
+ {
+#if VERBOSE
+ fprintf(stderr,
+ "sendto failed: %s\n", strerror(errno));
+#endif
+ }
+ else if (0 != err)
+ {
+ fprintf(stderr,
+ "Error: partial send of ICMP message\n");
+ }
+}
+
+
+/**
+ * We've received an ICMP response. Process it.
+ */
+static void
+process_icmp_response ()
+{
+ char buf[65536];
+ ssize_t have;
+ struct in_addr source_ip;
+ struct ip_header ip_pkt;
+ struct icmp_ttl_exceeded_header icmp_ttl;
+ struct icmp_echo_header icmp_echo;
+ struct udp_header udp_pkt;
+ size_t off;
+ uint16_t port;
+
+ have = read (icmpsock, buf, sizeof (buf));
+ if (-1 == have)
+ {
+ fprintf (stderr,
+ "Error reading raw socket: %s\n",
+ strerror (errno));
+ return;
+ }
+#if VERBOSE
+ fprintf (stderr,
+ "Received message of %u bytes\n",
+ (unsigned int) have);
+#endif
+ if (have < (ssize_t) (sizeof (struct ip_header) + sizeof (struct icmp_ttl_exceeded_header) + sizeof (struct ip_header)))
+ {
+ /* malformed */
+ return;
+ }
+ off = 0;
+ memcpy (&ip_pkt,
+ &buf[off],
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+ memcpy(&source_ip,
+ &ip_pkt.src_ip,
+ sizeof (source_ip));
+ memcpy (&icmp_ttl,
+ &buf[off],
+ sizeof (struct icmp_ttl_exceeded_header));
+ off += sizeof (struct icmp_ttl_exceeded_header);
+ if ( (ICMP_TIME_EXCEEDED != icmp_ttl.type) ||
+ (0 != icmp_ttl.code) )
+ {
+ /* different type than what we want */
+ return;
+ }
+ /* skip 2nd IP header */
+ memcpy (&ip_pkt,
+ &buf[off],
+ sizeof (struct ip_header));
+ off += sizeof (struct ip_header);
+
+ switch (ip_pkt.proto)
+ {
+ case IPPROTO_ICMP:
+ if (have != (sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct icmp_echo_header)) )
+ {
+ /* malformed */
+ return;
+ }
+ /* grab ICMP ECHO content */
+ memcpy (&icmp_echo,
+ &buf[off],
+ sizeof (struct icmp_echo_header));
+ port = (uint16_t) ntohl (icmp_echo.reserved);
+ break;
+ case IPPROTO_UDP:
+ if (have != (sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
+ sizeof (struct udp_header)) )
+ {
+ /* malformed */
+ return;
+ }
+ /* grab UDP content */
+ memcpy (&udp_pkt,
+ &buf[off],
+ sizeof (struct udp_header));
+ port = ntohs (udp_pkt.length);
+ break;
+ default:
+ /* different type than what we want */
+ return;
+ }
+
+ if (port == 0)
+ fprintf (stdout,
+ "%s\n",
+ inet_ntop (AF_INET,
+ &source_ip,
+ buf,
+ sizeof (buf)));
+ else
+ fprintf (stdout,
+ "%s:%u\n",
+ inet_ntop (AF_INET,
+ &source_ip,
+ buf,
+ sizeof (buf)),
+ (unsigned int) port);
+ fflush (stdout);
+}
+
+
+/**
+ * Create an ICMP raw socket for reading.
+ *
+ * @return -1 on error
+ */
+static int
+make_icmp_socket ()
+{
+ int ret;
+
+ ret = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP);
+ if (-1 == ret)
+ {
+ fprintf (stderr,
+ "Error opening RAW socket: %s\n",
+ strerror (errno));
+ return -1;
+ }
+ if (ret >= FD_SETSIZE)
+ {
+ fprintf (stderr,
+ "Socket number too large (%d > %u)\n",
+ ret,
+ (unsigned int) FD_SETSIZE);
+ close (ret);
+ return -1;
+ }
+ return ret;
+}
+
+
+/**
+ * Create an ICMP raw socket for writing.
+ *
+ * @return -1 on error
+ */
+static int
+make_raw_socket ()
+{
+ const int one = 1;
+ int ret;
+
+ ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
+ if (-1 == ret)
+ {
+ fprintf (stderr,
+ "Error opening RAW socket: %s\n",
+ strerror (errno));
+ return -1;
+ }
+ if (-1 == setsockopt(ret,
+ SOL_SOCKET,
+ SO_BROADCAST,
+ (char *)&one, sizeof(one)))
+ {
+ fprintf(stderr,
+ "setsockopt failed: %s\n",
+ strerror (errno));
+ close (ret);
+ return -1;
+ }
+ if (-1 == setsockopt(ret,
+ IPPROTO_IP,
+ IP_HDRINCL,
+ (char *)&one, sizeof(one)))
+ {
+ fprintf(stderr,
+ "setsockopt failed: %s\n",
+ strerror (errno));
+ close (ret);
+ return -1;
+ }
+ return ret;
+}
+
+
+/**
+ * Create a UDP socket for writinging.
+ *
+ * @param my_ip source address (our ip address)
+ * @return -1 on error
+ */
+static int
+make_udp_socket (const struct in_addr *my_ip)
+{
+ int ret;
+ struct sockaddr_in addr;
+
+ ret = socket (AF_INET, SOCK_DGRAM, 0);
+ if (-1 == ret)
+ {
+ fprintf (stderr,
+ "Error opening UDP socket: %s\n",
+ strerror (errno));
+ return -1;
+ }
+ memset (&addr,
+ 0,
+ sizeof (addr));
+ addr.sin_family = AF_INET;
+#if HAVE_SOCKADDR_IN_SIN_LEN
+ addr.sin_len = sizeof (struct sockaddr_in);
+#endif
+ addr.sin_addr = *my_ip;
+ addr.sin_port = htons (NAT_TRAV_PORT);
+
+ if (0 != bind (ret,
+ &addr,
+ sizeof(addr)))
+ {
+ fprintf (stderr,
+ "Error binding UDP socket to port %u: %s\n",
+ NAT_TRAV_PORT,
+ strerror (errno));
+ /* likely problematic, but not certain, try to continue */
+ }
+ return ret;
+}
+
+
+int
+main (int argc,
+ char *const *argv)
+{
+ struct in_addr external;
+ fd_set rs;
+ struct timeval tv;
+ uid_t uid;
+ unsigned int alt;
+
+ if (2 != argc)
+ {
+ fprintf (stderr,
+ "This program must be started with our (internal NAT) IP as the only argument.\n");
+ return 1;
+ }
+ if (1 != inet_pton (AF_INET, argv[1], &external))
+ {
+ fprintf (stderr,
+ "Error parsing IPv4 address: %s\n",
+ strerror (errno));
+ return 1;
+ }
+ if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
+ {
+ fprintf (stderr,
+ "Internal error converting dummy IP to binary.\n");
+ return 2;
+ }
+ if (-1 == (icmpsock = make_icmp_socket()))
+ {
+ return 3;
+ }
+ if (-1 == (rawsock = make_raw_socket()))
+ {
+ close (icmpsock);
+ return 3;
+ }
+ uid = getuid ();
+ if (0 != setresuid (uid, uid, uid))
+ {
+ fprintf (stderr,
+ "Failed to setresuid: %s\n",
+ strerror (errno));
+ /* not critical, continue anyway */
+ }
+ if (-1 == (udpsock = make_udp_socket(&external)))
+ {
+ close (icmpsock);
+ close (rawsock);
+ return 3;
+ }
+ alt = 0;
+ while (1)
+ {
+ FD_ZERO (&rs);
+ FD_SET (icmpsock, &rs);
+ tv.tv_sec = 0;
+ tv.tv_usec = ICMP_SEND_FREQUENCY_MS * 1000;
+ if (-1 == select (icmpsock + 1, &rs, NULL, NULL, &tv))
+ {
+ if (errno == EINTR)
+ continue;
+ fprintf (stderr,
+ "select failed: %s\n",
+ strerror (errno));
+ break;
+ }
+ if (1 == getppid()) /* Check the parent process id, if 1 the parent has died, so we should die too */
+ break;
+ if (FD_ISSET (icmpsock, &rs))
+ process_icmp_response ();
+ if (0 == (++alt % 2))
+ send_icmp_echo (&external);
+ else
+ send_udp ();
+ }
+ /* select failed (internal error or OS out of resources) */
+ close (icmpsock);
+ close (rawsock);
+ close (udpsock);
+ return 4;
+}
+
+
+/* end of gnunet-helper-nat-server.c */
+++ /dev/null
-/*
- This file is part of GNUnet.
- (C) 2010 Christian Grothoff (and other contributing authors)
-
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
-
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
-*/
-
-/**
- * @file src/nat/gnunet-nat-client-windows.c
- * @brief Tool to help bypass NATs using ICMP method; must run as
- * administrator on W32
- * This code is forx W32.
- * @author Nathan Evans
- *
- * This program will send ONE ICMP message using RAW sockets
- * to the IP address specified as the second argument. Since
- * it uses RAW sockets, it must be installed SUID or run as 'root'.
- * In order to keep the security risk of the resulting SUID binary
- * minimal, the program ONLY opens the RAW socket with root
- * privileges, then drops them and only then starts to process
- * command line arguments. The code also does not link against
- * any shared libraries (except libc) and is strictly minimal
- * (except for checking for errors). The following list of people
- * have reviewed this code and considered it safe since the last
- * modification (if you reviewed it, please have your name added
- * to the list):
- *
- * - Christian Grothoff
- * - Nathan Evans
- */
-#define _GNU_SOURCE
-
-#include <winsock2.h>
-#include <ws2tcpip.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <string.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <time.h>
-
-
-#define ICMP_ECHO 8
-#define IPDEFTTL 64
-#define ICMP_TIME_EXCEEDED 11
-
-/**
- * Must match IP given in the server.
- */
-#define DUMMY_IP "192.0.2.86"
-
-#define NAT_TRAV_PORT 22225
-
-/**
- * IPv4 header.
- */
-struct ip_header
-{
-
- /**
- * Version (4 bits) + Internet header length (4 bits)
- */
- uint8_t vers_ihl;
-
- /**
- * Type of service
- */
- uint8_t tos;
-
- /**
- * Total length
- */
- uint16_t pkt_len;
-
- /**
- * Identification
- */
- uint16_t id;
-
- /**
- * Flags (3 bits) + Fragment offset (13 bits)
- */
- uint16_t flags_frag_offset;
-
- /**
- * Time to live
- */
- uint8_t ttl;
-
- /**
- * Protocol
- */
- uint8_t proto;
-
- /**
- * Header checksum
- */
- uint16_t checksum;
-
- /**
- * Source address
- */
- uint32_t src_ip;
-
- /**
- * Destination address
- */
- uint32_t dst_ip;
-};
-
-
-/**
- * Format of ICMP packet.
- */
-struct icmp_ttl_exceeded_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t unused;
-
- /* followed by original payload */
-};
-
-struct icmp_echo_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t reserved;
-};
-
-/**
- * Beginning of UDP packet.
- */
-struct udp_header
-{
- uint16_t src_port;
-
- uint16_t dst_port;
-
- uint16_t length;
-
- uint16_t crc;
-};
-
-
-/**
- * Socket we use to send our ICMP packets.
- */
-static SOCKET rawsock;
-
-/**
- * Target "dummy" address.
- */
-static struct in_addr dummy;
-
-/**
- * Port we are listening on (communicated to the server).
- */
-static uint16_t port;
-
-
-
-/**
- * Convert IPv4 address from text to binary form.
- *
- * @param af address family
- * @param cp the address to print
- * @param buf where to write the address result
- * @return 1 on success
- */
-static int
-inet_pton (int af,
- const char *cp,
- struct in_addr *buf)
-{
- buf->s_addr = inet_addr(cp);
- if (buf->s_addr == INADDR_NONE)
- {
- fprintf(stderr,
- "Error %d handling address %s",
- WSAGetLastError(),
- cp);
- return 0;
- }
- return 1;
-}
-
-
-/**
- * CRC-16 for IP/ICMP headers.
- *
- * @param data what to calculate the CRC over
- * @param bytes number of bytes in data (must be multiple of 2)
- * @return the CRC 16.
- */
-static uint16_t
-calc_checksum(const uint16_t *data,
- unsigned int bytes)
-{
- uint32_t sum;
- unsigned int i;
-
- sum = 0;
- for (i=0;i<bytes/2;i++)
- sum += data[i];
- sum = (sum & 0xffff) + (sum >> 16);
- sum = htons(0xffff - sum);
- return sum;
-}
-
-
-/**
- * Send an ICMP message to the target.
- *
- * @param my_ip source address
- * @param other target address
- */
-static void
-send_icmp_udp (const struct in_addr *my_ip,
- const struct in_addr *other)
-{
- char packet[sizeof(struct ip_header) * 2 +
- sizeof(struct icmp_ttl_exceeded_header) +
- sizeof(struct udp_header)];
- struct ip_header ip_pkt;
- struct icmp_ttl_exceeded_header icmp_pkt;
- struct udp_header udp_pkt;
- struct sockaddr_in dst;
- size_t off;
- int err;
-
- /* ip header: send to (known) ip address */
- off = 0;
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons(sizeof (packet));
- ip_pkt.id = htons(256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = 128;
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = my_ip->s_addr;
- ip_pkt.dst_ip = other->s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy(&packet[off],
- &ip_pkt,
- sizeof(struct ip_header));
- off += sizeof(struct ip_header);
-
- icmp_pkt.type = ICMP_TIME_EXCEEDED;
- icmp_pkt.code = 0;
- icmp_pkt.checksum = 0;
- icmp_pkt.unused = 0;
- memcpy(&packet[off],
- &icmp_pkt,
- sizeof(struct icmp_ttl_exceeded_header));
- off += sizeof(struct icmp_ttl_exceeded_header);
-
- /* ip header of the presumably 'lost' udp packet */
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons(sizeof (struct ip_header) +
- sizeof (struct udp_header));
- ip_pkt.id = htons(0);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = 128;
- ip_pkt.proto = IPPROTO_UDP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = other->s_addr;
- ip_pkt.dst_ip = dummy.s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy(&packet[off],
- &ip_pkt,
- sizeof(struct ip_header));
- off += sizeof(struct ip_header);
-
- /* build UDP header */
- udp_pkt.src_port = htons(NAT_TRAV_PORT);
- udp_pkt.dst_port = htons(NAT_TRAV_PORT);
- udp_pkt.length = htons (port);
- udp_pkt.crc = 0;
- memcpy(&packet[off],
- &udp_pkt,
- sizeof(struct udp_header));
- off += sizeof(struct udp_header);
-
- /* no go back to calculate ICMP packet checksum */
- icmp_pkt.checksum = htons(calc_checksum((uint16_t*)&packet[off],
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct ip_header) +
- sizeof (struct udp_header)));
- memcpy (&packet[sizeof (struct ip_header)],
- &icmp_pkt,
- sizeof (struct icmp_ttl_exceeded_header));
-
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
- dst.sin_addr = *other;
- err = sendto(rawsock,
- packet,
- sizeof (packet), 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
- if (err < 0)
- {
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
- }
- else if (sizeof (packet) != (size_t) err)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * Send an ICMP message to the target.
- *
- * @param my_ip source address
- * @param other target address
- */
-static void
-send_icmp (const struct in_addr *my_ip,
- const struct in_addr *other)
-{
- struct ip_header ip_pkt;
- struct icmp_ttl_exceeded_header icmp_ttl;
- struct icmp_echo_header icmp_echo;
- struct sockaddr_in dst;
- char packet[sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof(struct icmp_echo_header)];
- size_t off;
- int err;
-
- /* ip header: send to (known) ip address */
- off = 0;
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons(256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = IPDEFTTL;
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = my_ip->s_addr;
- ip_pkt.dst_ip = other->s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy (&packet[off],
- &ip_pkt,
- sizeof (struct ip_header));
- off += sizeof (ip_pkt);
-
- /* icmp reply: time exceeded */
- icmp_ttl.type = ICMP_TIME_EXCEEDED;
- icmp_ttl.code = 0;
- icmp_ttl.checksum = 0;
- icmp_ttl.unused = 0;
- memcpy (&packet[off],
- &icmp_ttl,
- sizeof (struct icmp_ttl_exceeded_header));
- off += sizeof (struct icmp_ttl_exceeded_header);
-
- /* ip header of the presumably 'lost' udp packet */
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons(sizeof (struct ip_header) + sizeof (struct icmp_echo_header));
- ip_pkt.id = htons (256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = 1; /* real TTL would be 1 on a time exceeded packet */
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.src_ip = other->s_addr;
- ip_pkt.dst_ip = dummy.s_addr;
- ip_pkt.checksum = 0;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy (&packet[off],
- &ip_pkt,
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
-
- icmp_echo.type = ICMP_ECHO;
- icmp_echo.code = 0;
- icmp_echo.reserved = htonl(port);
- icmp_echo.checksum = 0;
- icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
- sizeof (struct icmp_echo_header)));
- memcpy (&packet[off],
- &icmp_echo,
- sizeof(struct icmp_echo_header));
-
- /* no go back to calculate ICMP packet checksum */
- off = sizeof (struct ip_header);
- icmp_ttl.checksum = htons(calc_checksum((uint16_t*) &packet[off],
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct ip_header) +
- sizeof (struct icmp_echo_header)));
- memcpy (&packet[off],
- &icmp_ttl,
- sizeof (struct icmp_ttl_exceeded_header));
-
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
- dst.sin_addr = *other;
-
- err = sendto(rawsock,
- packet,
- sizeof (packet), 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
-
- if (err < 0)
- {
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
- }
- else if (sizeof (packet) != (size_t) err)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * Create an ICMP raw socket.
- *
- * @return INVALID_SOCKET on error
- */
-static SOCKET
-make_raw_socket ()
-{
- DWORD bOptVal = TRUE;
- int bOptLen = sizeof(bOptVal);
- SOCKET ret;
-
- ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
- if (INVALID_SOCKET == ret)
- {
- fprintf (stderr,
- "Error opening RAW socket: %s\n",
- strerror (errno));
- return INVALID_SOCKET;
- }
- if (0 != setsockopt(ret, SOL_SOCKET, SO_BROADCAST, (char*)&bOptVal, bOptLen))
- {
- fprintf(stderr,
- "Error setting SO_BROADCAST to ON: %s\n",
- strerror (errno));
- closesocket(rawsock);
- return INVALID_SOCKET;
- }
-
- if (0 != setsockopt(ret, IPPROTO_IP, IP_HDRINCL, (char*)&bOptVal, bOptLen))
- {
- fprintf(stderr,
- "Error setting IP_HDRINCL to ON: %s\n",
- strerror (errno));
- closesocket(rawsock);
- return INVALID_SOCKET;
- }
- return ret;
-}
-
-
-int
-main (int argc, char *const *argv)
-{
- struct in_addr external;
- struct in_addr target;
- WSADATA wsaData;
-
- unsigned int p;
-
- if (argc != 4)
- {
- fprintf (stderr,
- "This program must be started with our IP, the targets external IP, and our port as arguments.\n");
- return 1;
- }
- if ( (1 != inet_pton (AF_INET, argv[1], &external)) ||
- (1 != inet_pton (AF_INET, argv[2], &target)) )
- {
- fprintf (stderr,
- "Error parsing IPv4 address: %s\n",
- strerror (errno));
- return 1;
- }
- if ( (1 != sscanf (argv[3], "%u", &p) ) ||
- (0 == p) ||
- (0xFFFF < p) )
- {
- fprintf (stderr,
- "Error parsing port value `%s'\n",
- argv[3]);
- return 1;
- }
- port = (uint16_t) p;
-
- if (0 != WSAStartup (MAKEWORD (2, 1), &wsaData))
- {
- fprintf (stderr, "Failed to find Winsock 2.1 or better.\n");
- return 2;
- }
- if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
- {
- fprintf (stderr,
- "Internal error converting dummy IP to binary.\n");
- return 2;
- }
- if (-1 == (rawsock = make_raw_socket()))
- return 3;
- send_icmp (&external,
- &target);
- send_icmp_udp (&external,
- &target);
- closesocket (rawsock);
- WSACleanup ();
- return 0;
-}
-
-/* end of gnunet-nat-client-windows.c */
+++ /dev/null
-/*
- This file is part of GNUnet.
- (C) 2010 Christian Grothoff (and other contributing authors)
-
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
-
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
-*/
-
-/**
- * @file src/nat/gnunet-nat-client.c
- * @brief Tool to help bypass NATs using ICMP method; must run as root (SUID will do)
- * This code will work under GNU/Linux only.
- * @author Christian Grothoff
- *
- * This program will send ONE ICMP message using RAW sockets
- * to the IP address specified as the second argument. Since
- * it uses RAW sockets, it must be installed SUID or run as 'root'.
- * In order to keep the security risk of the resulting SUID binary
- * minimal, the program ONLY opens the RAW socket with root
- * privileges, then drops them and only then starts to process
- * command line arguments. The code also does not link against
- * any shared libraries (except libc) and is strictly minimal
- * (except for checking for errors). The following list of people
- * have reviewed this code and considered it safe since the last
- * modification (if you reviewed it, please have your name added
- * to the list):
- *
- * - Christian Grothoff
- * - Nathan Evans
- * - Benjamin Kuperman (22 Aug 2010)
- */
-#if HAVE_CONFIG_H
-/* Just needed for HAVE_SOCKADDR_IN_SIN_LEN test macro! */
-#include "gnunet_config.h"
-#else
-#define _GNU_SOURCE
-#endif
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <string.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <netinet/ip.h>
-#include <netinet/ip_icmp.h>
-#include <netinet/in.h>
-
-/**
- * Must match IP given in the server.
- */
-#define DUMMY_IP "192.0.2.86"
-
-#define NAT_TRAV_PORT 22225
-
-/**
- * IPv4 header.
- */
-struct ip_header
-{
-
- /**
- * Version (4 bits) + Internet header length (4 bits)
- */
- uint8_t vers_ihl;
-
- /**
- * Type of service
- */
- uint8_t tos;
-
- /**
- * Total length
- */
- uint16_t pkt_len;
-
- /**
- * Identification
- */
- uint16_t id;
-
- /**
- * Flags (3 bits) + Fragment offset (13 bits)
- */
- uint16_t flags_frag_offset;
-
- /**
- * Time to live
- */
- uint8_t ttl;
-
- /**
- * Protocol
- */
- uint8_t proto;
-
- /**
- * Header checksum
- */
- uint16_t checksum;
-
- /**
- * Source address
- */
- uint32_t src_ip;
-
- /**
- * Destination address
- */
- uint32_t dst_ip;
-};
-
-/**
- * Format of ICMP packet.
- */
-struct icmp_ttl_exceeded_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t unused;
-
- /* followed by original payload */
-};
-
-struct icmp_echo_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t reserved;
-};
-
-/**
- * Beginning of UDP packet.
- */
-struct udp_header
-{
- uint16_t src_port;
-
- uint16_t dst_port;
-
- uint16_t length;
-
- uint16_t crc;
-};
-
-/**
- * Socket we use to send our fake ICMP replies.
- */
-static int rawsock;
-
-/**
- * Target "dummy" address of the packet we pretend to respond to.
- */
-static struct in_addr dummy;
-
-/**
- * Our "source" port.
- */
-static uint16_t port;
-
-
-/**
- * CRC-16 for IP/ICMP headers.
- *
- * @param data what to calculate the CRC over
- * @param bytes number of bytes in data (must be multiple of 2)
- * @return the CRC 16.
- */
-static uint16_t
-calc_checksum (const uint16_t *data,
- unsigned int bytes)
-{
- uint32_t sum;
- unsigned int i;
-
- sum = 0;
- for (i=0;i<bytes/2;i++)
- sum += data[i];
- sum = (sum & 0xffff) + (sum >> 16);
- sum = htons(0xffff - sum);
- return sum;
-}
-
-
-/**
- * Send an ICMP message to the target.
- *
- * @param my_ip source address
- * @param other target address
- */
-static void
-send_icmp_udp (const struct in_addr *my_ip,
- const struct in_addr *other)
-{
- char packet[sizeof(struct ip_header) * 2 +
- sizeof(struct icmp_ttl_exceeded_header) +
- sizeof(struct udp_header)];
- struct ip_header ip_pkt;
- struct icmp_ttl_exceeded_header icmp_pkt;
- struct udp_header udp_pkt;
- struct sockaddr_in dst;
- size_t off;
- int err;
-
- /* ip header: send to (known) ip address */
- off = 0;
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons(256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = 128;
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = my_ip->s_addr;
- ip_pkt.dst_ip = other->s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy(&packet[off],
- &ip_pkt,
- sizeof(struct ip_header));
- off += sizeof(struct ip_header);
-
- icmp_pkt.type = ICMP_TIME_EXCEEDED;
- icmp_pkt.code = 0;
- icmp_pkt.checksum = 0;
- icmp_pkt.unused = 0;
- memcpy(&packet[off],
- &icmp_pkt,
- sizeof(struct icmp_ttl_exceeded_header));
- off += sizeof(struct icmp_ttl_exceeded_header);
-
- /* ip header of the presumably 'lost' udp packet */
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons(sizeof (struct ip_header) +
- sizeof (struct udp_header));
- ip_pkt.id = htons(0);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = 128;
- ip_pkt.proto = IPPROTO_UDP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = other->s_addr;
- ip_pkt.dst_ip = dummy.s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy(&packet[off],
- &ip_pkt,
- sizeof(struct ip_header));
- off += sizeof(struct ip_header);
-
- /* build UDP header */
- udp_pkt.src_port = htons(NAT_TRAV_PORT);
- udp_pkt.dst_port = htons(NAT_TRAV_PORT);
- udp_pkt.length = htons (port);
- udp_pkt.crc = 0;
- memcpy(&packet[off],
- &udp_pkt,
- sizeof(struct udp_header));
- off += sizeof(struct udp_header);
-
- /* set ICMP checksum */
- icmp_pkt.checksum = htons(calc_checksum((uint16_t*)&packet[sizeof(struct ip_header)],
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct ip_header) +
- sizeof (struct udp_header)));
- memcpy (&packet[sizeof(struct ip_header)],
- &icmp_pkt,
- sizeof (struct icmp_ttl_exceeded_header));
-
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
-#if HAVE_SOCKADDR_IN_SIN_LEN
- dst.sin_len = sizeof (struct sockaddr_in);
-#endif
- dst.sin_addr = *other;
- err = sendto(rawsock,
- packet,
- sizeof (packet), 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
- if (err < 0)
- {
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
- }
- else if (sizeof (packet) != (size_t) err)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * Send an ICMP message to the target.
- *
- * @param my_ip source address
- * @param other target address
- */
-static void
-send_icmp (const struct in_addr *my_ip,
- const struct in_addr *other)
-{
- struct ip_header ip_pkt;
- struct icmp_ttl_exceeded_header icmp_ttl;
- struct icmp_echo_header icmp_echo;
- struct sockaddr_in dst;
- char packet[sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct icmp_echo_header)];
- size_t off;
- int err;
-
- /* ip header: send to (known) ip address */
- off = 0;
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons (256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = IPDEFTTL;
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = my_ip->s_addr;
- ip_pkt.dst_ip = other->s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy (&packet[off],
- &ip_pkt,
- sizeof (struct ip_header));
- off = sizeof (ip_pkt);
-
- /* icmp reply: time exceeded */
- icmp_ttl.type = ICMP_TIME_EXCEEDED;
- icmp_ttl.code = 0;
- icmp_ttl.checksum = 0;
- icmp_ttl.unused = 0;
- memcpy (&packet[off],
- &icmp_ttl,
- sizeof (struct icmp_ttl_exceeded_header));
- off += sizeof (struct icmp_ttl_exceeded_header);
-
- /* ip header of the presumably 'lost' udp packet */
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons (sizeof (struct ip_header) + sizeof (struct icmp_echo_header));
- ip_pkt.id = htons (256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = 1; /* real TTL would be 1 on a time exceeded packet */
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.src_ip = other->s_addr;
- ip_pkt.dst_ip = dummy.s_addr;
- ip_pkt.checksum = 0;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy (&packet[off],
- &ip_pkt,
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
-
- icmp_echo.type = ICMP_ECHO;
- icmp_echo.code = 0;
- icmp_echo.reserved = htonl (port);
- icmp_echo.checksum = 0;
- icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
- sizeof (struct icmp_echo_header)));
- memcpy (&packet[off],
- &icmp_echo,
- sizeof(struct icmp_echo_header));
-
- /* no go back to calculate ICMP packet checksum */
- off = sizeof (struct ip_header);
- icmp_ttl.checksum = htons(calc_checksum((uint16_t*) &packet[off],
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct ip_header) +
- sizeof (struct icmp_echo_header)));
- memcpy (&packet[off],
- &icmp_ttl,
- sizeof (struct icmp_ttl_exceeded_header));
-
- /* prepare for transmission */
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
-#if HAVE_SOCKADDR_IN_SIN_LEN
- dst.sin_len = sizeof (struct sockaddr_in);
-#endif
- dst.sin_addr = *other;
- err = sendto(rawsock,
- packet,
- sizeof (packet), 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
- if (err < 0)
- {
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
- }
- else if (sizeof (packet) != (size_t) err)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * Create an ICMP raw socket for writing.
- *
- * @return -1 on error
- */
-static int
-make_raw_socket ()
-{
- const int one = 1;
- int ret;
-
- ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
- if (-1 == ret)
- {
- fprintf (stderr,
- "Error opening RAW socket: %s\n",
- strerror (errno));
- return -1;
- }
- if (0 != setsockopt(ret, SOL_SOCKET, SO_BROADCAST,
- (char *)&one, sizeof(one)))
- {
- fprintf(stderr,
- "setsockopt failed: %s\n",
- strerror (errno));
- close (ret);
- return -1;
- }
- if (0 != setsockopt(ret, IPPROTO_IP, IP_HDRINCL,
- (char *)&one, sizeof(one)))
- {
- fprintf(stderr,
- "setsockopt failed: %s\n",
- strerror (errno));
- close (ret);
- return -1;
- }
- return ret;
-}
-
-
-int
-main (int argc, char *const *argv)
-{
- struct in_addr external;
- struct in_addr target;
- uid_t uid;
- unsigned int p;
-
- if (4 != argc)
- {
- fprintf (stderr,
- "This program must be started with our IP, the targets external IP, and our port as arguments.\n");
- return 1;
- }
- if ( (1 != inet_pton (AF_INET, argv[1], &external)) ||
- (1 != inet_pton (AF_INET, argv[2], &target)) )
- {
- fprintf (stderr,
- "Error parsing IPv4 address: %s\n",
- strerror (errno));
- return 1;
- }
- if ( (1 != sscanf (argv[3], "%u", &p) ) ||
- (0 == p) ||
- (0xFFFF < p) )
- {
- fprintf (stderr,
- "Error parsing port value `%s'\n",
- argv[3]);
- return 1;
- }
- port = (uint16_t) p;
- if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
- {
- fprintf (stderr,
- "Internal error converting dummy IP to binary.\n");
- return 2;
- }
- if (-1 == (rawsock = make_raw_socket()))
- return 2;
- uid = getuid ();
- if (0 != setresuid (uid, uid, uid))
- {
- fprintf (stderr,
- "Failed to setresuid: %s\n",
- strerror (errno));
- /* not critical, continue anyway */
- }
- send_icmp (&external,
- &target);
- send_icmp_udp (&external,
- &target);
- close (rawsock);
- return 0;
-}
-
-/* end of gnunet-nat-client.c */
+++ /dev/null
-/*
- This file is part of GNUnet.
- (C) 2010 Christian Grothoff (and other contributing authors)
-
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
-
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
-*/
-
-/**
- * @file src/nat/gnunet-nat-server-windows.c
- * @brief Windows tool to help bypass NATs using ICMP method
- * This code will work under W32 only
- * @author Christian Grothoff
- *
- * This program will send ONE ICMP message every 500 ms RAW sockets
- * to a DUMMY IP address and also listens for ICMP replies. Since
- * it uses RAW sockets, it must be run as an administrative user.
- * In order to keep the security risk of the resulting binary
- * minimal, the program ONLY opens the two RAW sockets with administrative
- * privileges, then drops them and only then starts to process
- * command line arguments. The code also does not link against
- * any shared libraries (except libc) and is strictly minimal
- * (except for checking for errors). The following list of people
- * have reviewed this code and considered it safe since the last
- * modification (if you reviewed it, please have your name added
- * to the list):
- *
- * - Nathan Evans
- * - Christian Grothoff
- */
-#define _GNU_SOURCE
-
-
-#include <winsock2.h>
-#include <ws2tcpip.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <string.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <time.h>
-
-/**
- * Should we print some debug output?
- */
-#define VERBOSE 0
-
-/**
- * Must match IP given in the client.
- */
-#define DUMMY_IP "192.0.2.86"
-
-/**
- * Default Port
- */
-#define NAT_TRAV_PORT 22225
-
-/**
- * TTL to use for our outgoing messages.
- */
-#define IPDEFTTL 64
-
-#define ICMP_ECHO 8
-
-#define ICMP_TIME_EXCEEDED 11
-
-/**
- * How often do we send our ICMP messages to receive replies?
- */
-#define ICMP_SEND_FREQUENCY_MS 500
-
-/**
- * IPv4 header.
- */
-struct ip_header
-{
-
- /**
- * Version (4 bits) + Internet header length (4 bits)
- */
- uint8_t vers_ihl;
-
- /**
- * Type of service
- */
- uint8_t tos;
-
- /**
- * Total length
- */
- uint16_t pkt_len;
-
- /**
- * Identification
- */
- uint16_t id;
-
- /**
- * Flags (3 bits) + Fragment offset (13 bits)
- */
- uint16_t flags_frag_offset;
-
- /**
- * Time to live
- */
- uint8_t ttl;
-
- /**
- * Protocol
- */
- uint8_t proto;
-
- /**
- * Header checksum
- */
- uint16_t checksum;
-
- /**
- * Source address
- */
- uint32_t src_ip;
-
- /**
- * Destination address
- */
- uint32_t dst_ip;
-};
-
-/**
- * Format of ICMP packet.
- */
-struct icmp_ttl_exceeded_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t unused;
-
- /* followed by original payload */
-};
-
-struct icmp_echo_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t reserved;
-};
-
-/**
- * Beginning of UDP packet.
- */
-struct udp_header
-{
- uint16_t src_port;
-
- uint16_t dst_port;
-
- uint16_t length;
-
- uint16_t crc;
-};
-
-/**
- * Socket we use to receive "fake" ICMP replies.
- */
-static SOCKET icmpsock;
-
-/**
- * Socket we use to send our ICMP requests.
- */
-static SOCKET rawsock;
-
-/**
- * Socket we use to send our UDP requests.
- */
-static SOCKET udpsock;
-
-/**
- * Target "dummy" address.
- */
-static struct in_addr dummy;
-
-
-/**
- * CRC-16 for IP/ICMP headers.
- *
- * @param data what to calculate the CRC over
- * @param bytes number of bytes in data (must be multiple of 2)
- * @return the CRC 16.
- */
-static uint16_t
-calc_checksum(const uint16_t *data,
- unsigned int bytes)
-{
- uint32_t sum;
- unsigned int i;
-
- sum = 0;
- for (i=0;i<bytes/2;i++)
- sum += data[i];
- sum = (sum & 0xffff) + (sum >> 16);
- sum = htons(0xffff - sum);
- return sum;
-}
-
-
-/**
- * Convert IPv4 address from text to binary form.
- *
- * @param af address family
- * @param cp the address to print
- * @param buf where to write the address result
- * @return 1 on success
- */
-static int
-inet_pton (int af,
- const char *cp,
- struct in_addr *buf)
-{
- buf->s_addr = inet_addr(cp);
- if (buf->s_addr == INADDR_NONE)
- {
- fprintf(stderr,
- "Error %d handling address %s",
- WSAGetLastError(),
- cp);
- return 0;
- }
- return 1;
-}
-
-
-/**
- * Send an ICMP message to the dummy IP.
- *
- * @param my_ip source address (our ip address)
- */
-static void
-send_icmp_echo (const struct in_addr *my_ip)
-{
- char packet[sizeof (struct ip_header) + sizeof (struct icmp_echo_header)];
- struct icmp_echo_header icmp_echo;
- struct ip_header ip_pkt;
- struct sockaddr_in dst;
- size_t off;
- int err;
-
- off = 0;
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons (256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = IPDEFTTL;
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = my_ip->s_addr;
- ip_pkt.dst_ip = dummy.s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy (&packet[off],
- &ip_pkt,
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
-
- icmp_echo.type = ICMP_ECHO;
- icmp_echo.code = 0;
- icmp_echo.reserved = 0;
- icmp_echo.checksum = 0;
- icmp_echo.checksum = htons(calc_checksum((uint16_t*) &icmp_echo,
- sizeof (struct icmp_echo_header)));
- memcpy (&packet[off],
- &icmp_echo,
- sizeof (struct icmp_echo_header));
- off += sizeof (struct icmp_echo_header);
-
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
- dst.sin_addr = dummy;
- err = sendto(rawsock,
- packet, off, 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
- if (err < 0)
- {
-#if VERBOSE
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
-#endif
- }
- else if (err != off)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * Send a UDP message to the dummy IP.
- */
-static void
-send_udp ()
-{
- struct sockaddr_in dst;
- ssize_t err;
-
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
- dst.sin_addr = dummy;
- dst.sin_port = htons (NAT_TRAV_PORT);
- err = sendto(udpsock,
- NULL, 0, 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
- if (err < 0)
- {
-#if VERBOSE
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
-#endif
- }
- else if (0 != err)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * We've received an ICMP response. Process it.
- */
-static void
-process_icmp_response ()
-{
- char buf[65536];
- ssize_t have;
- struct in_addr source_ip;
- struct ip_header ip_pkt;
- struct icmp_ttl_exceeded_header icmp_ttl;
- struct icmp_echo_header icmp_echo;
- struct udp_header udp_pkt;
- size_t off;
- uint16_t port;
- DWORD ssize;
-
- have = read (icmpsock, buf, sizeof (buf));
- if (have == -1)
- {
- fprintf (stderr,
- "Error reading raw socket: %s\n",
- strerror (errno));
- return;
- }
-#if VERBOSE
- fprintf (stderr,
- "Received message of %u bytes\n",
- (unsigned int) have);
-#endif
- if (have < (ssize_t) (sizeof (struct ip_header) + sizeof (struct icmp_ttl_exceeded_header) + sizeof (struct ip_header)))
- {
- /* malformed */
- return;
- }
- off = 0;
- memcpy (&ip_pkt,
- &buf[off],
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
- memcpy(&source_ip,
- &ip_pkt.src_ip,
- sizeof (source_ip));
- memcpy (&icmp_ttl,
- &buf[off],
- sizeof (struct icmp_ttl_exceeded_header));
- off += sizeof (struct icmp_ttl_exceeded_header);
- if ( (ICMP_TIME_EXCEEDED != icmp_ttl.type) ||
- (0 != icmp_ttl.code) )
- {
- /* different type than what we want */
- return;
- }
- /* skip 2nd IP header */
- memcpy (&ip_pkt,
- &buf[off],
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
-
- switch (ip_pkt.proto)
- {
- case IPPROTO_ICMP:
- if (have != (sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct icmp_echo_header)) )
- {
- /* malformed */
- return;
- }
- /* grab ICMP ECHO content */
- memcpy (&icmp_echo,
- &buf[off],
- sizeof (struct icmp_echo_header));
- port = (uint16_t) ntohl (icmp_echo.reserved);
- break;
- case IPPROTO_UDP:
- if (have != (sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct udp_header)) )
- {
- /* malformed */
- return;
- }
- /* grab UDP content */
- memcpy (&udp_pkt,
- &buf[off],
- sizeof (struct udp_header));
- port = ntohs (udp_pkt.length);
- break;
- default:
- /* different type than what we want */
- return;
- }
-
- ssize = sizeof(buf);
- WSAAddressToString((LPSOCKADDR)&source_ip,
- sizeof(source_ip),
- NULL,
- buf,
- &ssize);
- if (port == 0)
- fprintf (stdout,
- "%s\n",
- buf);
- else
- fprintf (stdout,
- "%s:%u\n",
- buf,
- (unsigned int) port);
- fflush (stdout);
-}
-
-
-/**
- * Create an ICMP raw socket for reading.
- *
- * @return INVALID_SOCKET on error
- */
-static SOCKET
-make_icmp_socket ()
-{
- SOCKET ret;
-
- ret = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP);
- if (INVALID_SOCKET == ret)
- {
- fprintf (stderr,
- "Error opening RAW socket: %s\n",
- strerror (errno));
- return INVALID_SOCKET;
- }
- return ret;
-}
-
-
-/**
- * Create an ICMP raw socket for writing.
- *
- * @return INVALID_SOCKET on error
- */
-static SOCKET
-make_raw_socket ()
-{
- DWORD bOptVal = TRUE;
- int bOptLen = sizeof(bOptVal);
-
- rawsock = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP);
- if (INVALID_SOCKET == rawsock)
- {
- fprintf (stderr,
- "Error opening RAW socket: %s\n",
- strerror (errno));
- return INVALID_SOCKET;
- }
-
- if (0 != setsockopt(rawsock,
- SOL_SOCKET,
- SO_BROADCAST,
- (char*)&bOptVal, bOptLen))
- {
- fprintf(stderr,
- "Error setting SO_BROADCAST to ON: %s\n",
- strerror (errno));
- closesocket(rawsock);
- return INVALID_SOCKET;
- }
- if (0 != setsockopt(rawsock,
- IPPROTO_IP,
- IP_HDRINCL,
- (char*)&bOptVal, bOptLen))
- {
- fprintf(stderr,
- "Error setting IP_HDRINCL to ON: %s\n",
- strerror (errno));
- closesocket(rawsock);
- return INVALID_SOCKET;
- }
- return rawsock;
-}
-
-
-/**
- * Create a UDP socket for writing.
- *
- * @param my_ip source address (our ip address)
- * @return INVALID_SOCKET on error
- */
-static SOCKET
-make_udp_socket (const struct in_addr *my_ip)
-{
- SOCKET ret;
- struct sockaddr_in addr;
-
- ret = socket (AF_INET, SOCK_DGRAM, 0);
- if (INVALID_SOCKET == ret)
- {
- fprintf (stderr,
- "Error opening UDP socket: %s\n",
- strerror (errno));
- return INVALID_SOCKET;
- }
- memset (&addr, 0, sizeof (addr));
- addr.sin_family = AF_INET;
- addr.sin_addr = *my_ip;
- addr.sin_port = htons (NAT_TRAV_PORT);
- if (0 != bind (ret,
- (struct sockaddr *)&addr,
- sizeof(addr)))
- {
- fprintf (stderr,
- "Error binding UDP socket to port %u: %s\n",
- NAT_TRAV_PORT,
- strerror (errno));
- /* likely problematic, but not certain, try to continue */
- }
- return ret;
-}
-
-
-int
-main (int argc,
- char *const *argv)
-{
- struct in_addr external;
- fd_set rs;
- struct timeval tv;
- WSADATA wsaData;
- unsigned int alt;
-
- alt = 0;
- if (2 != argc)
- {
- fprintf (stderr,
- "This program must be started with our (internal NAT) IP as the only argument.\n");
- return 1;
- }
- if (1 != inet_pton (AF_INET, argv[1], &external))
- {
- fprintf (stderr,
- "Error parsing IPv4 address: %s, error %s\n",
- argv[1], strerror (errno));
- return 1;
- }
- if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
- {
- fprintf (stderr,
- "Internal error converting dummy IP to binary.\n");
- return 2;
- }
- if (WSAStartup (MAKEWORD (2, 1), &wsaData) != 0)
- {
- fprintf (stderr, "Failed to find Winsock 2.1 or better.\n");
- return 2;
- }
- if (INVALID_SOCKET == (icmpsock = make_icmp_socket()))
- {
- return 3;
- }
- if (INVALID_SOCKET == (make_raw_socket()))
- {
- closesocket (icmpsock);
- return 3;
- }
- if (INVALID_SOCKET == (udpsock = make_udp_socket(&external)))
- {
- closesocket (icmpsock);
- closesocket (rawsock);
- return 3;
- }
- while (1)
- {
- FD_ZERO (&rs);
- FD_SET (icmpsock, &rs);
- tv.tv_sec = 0;
- tv.tv_usec = ICMP_SEND_FREQUENCY_MS * 1000;
- if (-1 == select (icmpsock + 1, &rs, NULL, NULL, &tv))
- {
- if (errno == EINTR)
- continue;
- fprintf (stderr,
- "select failed: %s\n",
- strerror (errno));
- break;
- }
- if (FD_ISSET (icmpsock, &rs))
- process_icmp_response ();
- if (0 == (++alt % 2))
- send_icmp_echo (&external);
- else
- send_udp ();
- }
- /* select failed (internal error or OS out of resources) */
- closesocket(icmpsock);
- closesocket(rawsock);
- closesocket(udpsock);
- WSACleanup ();
- return 4;
-}
-
-
-/* end of gnunet-nat-server-windows.c */
/**
* @file src/nat/gnunet-nat-server.c
- * @brief Tool to help bypass NATs using ICMP method; must run as root (SUID will do)
- * This code will work under GNU/Linux only (or maybe BSDs, but never W32)
+ * @brief Daemon to run on 'gnunet.org' to help test NAT traversal code
* @author Christian Grothoff
*
- * This program will send ONE ICMP message every 500 ms RAW sockets
- * to a DUMMY IP address and also listens for ICMP replies. Since
- * it uses RAW sockets, it must be installed SUID or run as 'root'.
- * In order to keep the security risk of the resulting SUID binary
- * minimal, the program ONLY opens the two RAW sockets with root
- * privileges, then drops them and only then starts to process
- * command line arguments. The code also does not link against
- * any shared libraries (except libc) and is strictly minimal
- * (except for checking for errors). The following list of people
- * have reviewed this code and considered it safe since the last
- * modification (if you reviewed it, please have your name added
- * to the list):
- *
- * - Christian Grothoff
- * - Nathan Evans
- * - Benjamin Kuperman (22 Aug 2010)
*/
-#if HAVE_CONFIG_H
-/* Just needed for HAVE_SOCKADDR_IN_SIN_LEN test macro! */
-#include "gnunet_config.h"
-#else
-#define _GNU_SOURCE
-#endif
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <sys/select.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <string.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <time.h>
-#include <netinet/ip.h>
-#include <netinet/ip_icmp.h>
-#include <netinet/in.h>
+#include "platform.h"
+#include "gnunet_util_lib.h"
/**
* Should we print some debug output?
#define VERBOSE 0
/**
- * Must match IP given in the client.
- */
-#define DUMMY_IP "192.0.2.86"
-
-/**
- * Port for UDP
- */
-#define NAT_TRAV_PORT 22225
-
-/**
- * How often do we send our ICMP messages to receive replies?
- */
-#define ICMP_SEND_FREQUENCY_MS 500
-
-/**
- * IPv4 header.
- */
-struct ip_header
-{
-
- /**
- * Version (4 bits) + Internet header length (4 bits)
- */
- uint8_t vers_ihl;
-
- /**
- * Type of service
- */
- uint8_t tos;
-
- /**
- * Total length
- */
- uint16_t pkt_len;
-
- /**
- * Identification
- */
- uint16_t id;
-
- /**
- * Flags (3 bits) + Fragment offset (13 bits)
- */
- uint16_t flags_frag_offset;
-
- /**
- * Time to live
- */
- uint8_t ttl;
-
- /**
- * Protocol
- */
- uint8_t proto;
-
- /**
- * Header checksum
- */
- uint16_t checksum;
-
- /**
- * Source address
- */
- uint32_t src_ip;
-
- /**
- * Destination address
- */
- uint32_t dst_ip;
-};
-
-/**
- * Format of ICMP packet.
- */
-struct icmp_ttl_exceeded_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t unused;
-
- /* followed by original payload */
-};
-
-struct icmp_echo_header
-{
- uint8_t type;
-
- uint8_t code;
-
- uint16_t checksum;
-
- uint32_t reserved;
-};
-
-
-/**
- * Beginning of UDP packet.
- */
-struct udp_header
-{
- uint16_t src_port;
-
- uint16_t dst_port;
-
- uint16_t length;
-
- uint16_t crc;
-};
-
-/**
- * Socket we use to receive "fake" ICMP replies.
- */
-static int icmpsock;
-
-/**
- * Socket we use to send our ICMP requests.
- */
-static int rawsock;
-
-/**
- * Socket we use to send our UDP requests.
- */
-static int udpsock;
-
-/**
- * Target "dummy" address.
- */
-static struct in_addr dummy;
-
-
-/**
- * CRC-16 for IP/ICMP headers.
- *
- * @param data what to calculate the CRC over
- * @param bytes number of bytes in data (must be multiple of 2)
- * @return the CRC 16.
- */
-static uint16_t
-calc_checksum(const uint16_t *data,
- unsigned int bytes)
-{
- uint32_t sum;
- unsigned int i;
-
- sum = 0;
- for (i=0;i<bytes/2;i++)
- sum += data[i];
- sum = (sum & 0xffff) + (sum >> 16);
- sum = htons(0xffff - sum);
- return sum;
-}
-
-
-/**
- * Send an ICMP message to the dummy IP.
+ * Main function that will be run.
*
- * @param my_ip source address (our ip address)
- */
-static void
-send_icmp_echo (const struct in_addr *my_ip)
-{
- char packet[sizeof (struct ip_header) + sizeof (struct icmp_echo_header)];
- struct icmp_echo_header icmp_echo;
- struct ip_header ip_pkt;
- struct sockaddr_in dst;
- size_t off;
- int err;
-
- off = 0;
- ip_pkt.vers_ihl = 0x45;
- ip_pkt.tos = 0;
- ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons (256);
- ip_pkt.flags_frag_offset = 0;
- ip_pkt.ttl = IPDEFTTL;
- ip_pkt.proto = IPPROTO_ICMP;
- ip_pkt.checksum = 0;
- ip_pkt.src_ip = my_ip->s_addr;
- ip_pkt.dst_ip = dummy.s_addr;
- ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
- sizeof (struct ip_header)));
- memcpy (&packet[off],
- &ip_pkt,
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
-
- icmp_echo.type = ICMP_ECHO;
- icmp_echo.code = 0;
- icmp_echo.checksum = 0;
- icmp_echo.reserved = 0;
- icmp_echo.checksum = htons(calc_checksum((uint16_t*)&icmp_echo,
- sizeof (struct icmp_echo_header)));
- memcpy (&packet[off],
- &icmp_echo,
- sizeof (struct icmp_echo_header));
- off += sizeof (struct icmp_echo_header);
-
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
-#if HAVE_SOCKADDR_IN_SIN_LEN
- dst.sin_len = sizeof (struct sockaddr_in);
-#endif
- dst.sin_addr = dummy;
- err = sendto(rawsock,
- packet, off, 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
- if (err < 0)
- {
-#if VERBOSE
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
-#endif
- }
- else if (sizeof (packet) != err)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * Send a UDP message to the dummy IP.
- */
-static void
-send_udp ()
-{
- struct sockaddr_in dst;
- ssize_t err;
-
- memset (&dst, 0, sizeof (dst));
- dst.sin_family = AF_INET;
-#if HAVE_SOCKADDR_IN_SIN_LEN
- dst.sin_len = sizeof (struct sockaddr_in);
-#endif
- dst.sin_addr = dummy;
- dst.sin_port = htons (NAT_TRAV_PORT);
- err = sendto(udpsock,
- NULL, 0, 0,
- (struct sockaddr*)&dst,
- sizeof(dst));
- if (err < 0)
- {
-#if VERBOSE
- fprintf(stderr,
- "sendto failed: %s\n", strerror(errno));
-#endif
- }
- else if (0 != err)
- {
- fprintf(stderr,
- "Error: partial send of ICMP message\n");
- }
-}
-
-
-/**
- * We've received an ICMP response. Process it.
+ * @param cls closure
+ * @param args remaining command-line arguments
+ * @param cfgfile name of the configuration file used (for saving, can be NULL!)
+ * @param c configuration
*/
static void
-process_icmp_response ()
-{
- char buf[65536];
- ssize_t have;
- struct in_addr source_ip;
- struct ip_header ip_pkt;
- struct icmp_ttl_exceeded_header icmp_ttl;
- struct icmp_echo_header icmp_echo;
- struct udp_header udp_pkt;
- size_t off;
- uint16_t port;
-
- have = read (icmpsock, buf, sizeof (buf));
- if (-1 == have)
- {
- fprintf (stderr,
- "Error reading raw socket: %s\n",
- strerror (errno));
- return;
- }
-#if VERBOSE
- fprintf (stderr,
- "Received message of %u bytes\n",
- (unsigned int) have);
-#endif
- if (have < (ssize_t) (sizeof (struct ip_header) + sizeof (struct icmp_ttl_exceeded_header) + sizeof (struct ip_header)))
- {
- /* malformed */
- return;
- }
- off = 0;
- memcpy (&ip_pkt,
- &buf[off],
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
- memcpy(&source_ip,
- &ip_pkt.src_ip,
- sizeof (source_ip));
- memcpy (&icmp_ttl,
- &buf[off],
- sizeof (struct icmp_ttl_exceeded_header));
- off += sizeof (struct icmp_ttl_exceeded_header);
- if ( (ICMP_TIME_EXCEEDED != icmp_ttl.type) ||
- (0 != icmp_ttl.code) )
- {
- /* different type than what we want */
- return;
- }
- /* skip 2nd IP header */
- memcpy (&ip_pkt,
- &buf[off],
- sizeof (struct ip_header));
- off += sizeof (struct ip_header);
-
- switch (ip_pkt.proto)
- {
- case IPPROTO_ICMP:
- if (have != (sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct icmp_echo_header)) )
- {
- /* malformed */
- return;
- }
- /* grab ICMP ECHO content */
- memcpy (&icmp_echo,
- &buf[off],
- sizeof (struct icmp_echo_header));
- port = (uint16_t) ntohl (icmp_echo.reserved);
- break;
- case IPPROTO_UDP:
- if (have != (sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
- sizeof (struct udp_header)) )
- {
- /* malformed */
- return;
- }
- /* grab UDP content */
- memcpy (&udp_pkt,
- &buf[off],
- sizeof (struct udp_header));
- port = ntohs (udp_pkt.length);
- break;
- default:
- /* different type than what we want */
- return;
- }
-
- if (port == 0)
- fprintf (stdout,
- "%s\n",
- inet_ntop (AF_INET,
- &source_ip,
- buf,
- sizeof (buf)));
- else
- fprintf (stdout,
- "%s:%u\n",
- inet_ntop (AF_INET,
- &source_ip,
- buf,
- sizeof (buf)),
- (unsigned int) port);
- fflush (stdout);
-}
-
-
-/**
- * Create an ICMP raw socket for reading.
- *
- * @return -1 on error
- */
-static int
-make_icmp_socket ()
-{
- int ret;
-
- ret = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP);
- if (-1 == ret)
- {
- fprintf (stderr,
- "Error opening RAW socket: %s\n",
- strerror (errno));
- return -1;
- }
- if (ret >= FD_SETSIZE)
- {
- fprintf (stderr,
- "Socket number too large (%d > %u)\n",
- ret,
- (unsigned int) FD_SETSIZE);
- close (ret);
- return -1;
- }
- return ret;
-}
-
-
-/**
- * Create an ICMP raw socket for writing.
- *
- * @return -1 on error
- */
-static int
-make_raw_socket ()
-{
- const int one = 1;
- int ret;
-
- ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
- if (-1 == ret)
- {
- fprintf (stderr,
- "Error opening RAW socket: %s\n",
- strerror (errno));
- return -1;
- }
- if (-1 == setsockopt(ret,
- SOL_SOCKET,
- SO_BROADCAST,
- (char *)&one, sizeof(one)))
- {
- fprintf(stderr,
- "setsockopt failed: %s\n",
- strerror (errno));
- close (ret);
- return -1;
- }
- if (-1 == setsockopt(ret,
- IPPROTO_IP,
- IP_HDRINCL,
- (char *)&one, sizeof(one)))
- {
- fprintf(stderr,
- "setsockopt failed: %s\n",
- strerror (errno));
- close (ret);
- return -1;
- }
- return ret;
-}
-
-
-/**
- * Create a UDP socket for writinging.
- *
- * @param my_ip source address (our ip address)
- * @return -1 on error
- */
-static int
-make_udp_socket (const struct in_addr *my_ip)
+run (void *cls,
+ char *const *args,
+ const char *cfgfile,
+ const struct GNUNET_CONFIGURATION_Handle * c)
{
- int ret;
- struct sockaddr_in addr;
-
- ret = socket (AF_INET, SOCK_DGRAM, 0);
- if (-1 == ret)
- {
- fprintf (stderr,
- "Error opening UDP socket: %s\n",
- strerror (errno));
- return -1;
- }
- memset (&addr,
- 0,
- sizeof (addr));
- addr.sin_family = AF_INET;
-#if HAVE_SOCKADDR_IN_SIN_LEN
- addr.sin_len = sizeof (struct sockaddr_in);
-#endif
- addr.sin_addr = *my_ip;
- addr.sin_port = htons (NAT_TRAV_PORT);
-
- if (0 != bind (ret,
- &addr,
- sizeof(addr)))
- {
- fprintf (stderr,
- "Error binding UDP socket to port %u: %s\n",
- NAT_TRAV_PORT,
- strerror (errno));
- /* likely problematic, but not certain, try to continue */
- }
- return ret;
}
int
-main (int argc,
- char *const *argv)
+main (int argc, char *const argv[])
{
- struct in_addr external;
- fd_set rs;
- struct timeval tv;
- uid_t uid;
- unsigned int alt;
-
- if (2 != argc)
- {
- fprintf (stderr,
- "This program must be started with our (internal NAT) IP as the only argument.\n");
- return 1;
- }
- if (1 != inet_pton (AF_INET, argv[1], &external))
- {
- fprintf (stderr,
- "Error parsing IPv4 address: %s\n",
- strerror (errno));
- return 1;
- }
- if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
- {
- fprintf (stderr,
- "Internal error converting dummy IP to binary.\n");
- return 2;
- }
- if (-1 == (icmpsock = make_icmp_socket()))
- {
- return 3;
- }
- if (-1 == (rawsock = make_raw_socket()))
- {
- close (icmpsock);
- return 3;
- }
- uid = getuid ();
- if (0 != setresuid (uid, uid, uid))
- {
- fprintf (stderr,
- "Failed to setresuid: %s\n",
- strerror (errno));
- /* not critical, continue anyway */
- }
- if (-1 == (udpsock = make_udp_socket(&external)))
- {
- close (icmpsock);
- close (rawsock);
- return 3;
- }
- alt = 0;
- while (1)
- {
- FD_ZERO (&rs);
- FD_SET (icmpsock, &rs);
- tv.tv_sec = 0;
- tv.tv_usec = ICMP_SEND_FREQUENCY_MS * 1000;
- if (-1 == select (icmpsock + 1, &rs, NULL, NULL, &tv))
- {
- if (errno == EINTR)
- continue;
- fprintf (stderr,
- "select failed: %s\n",
- strerror (errno));
- break;
- }
- if (1 == getppid()) /* Check the parent process id, if 1 the parent has died, so we should die too */
- break;
- if (FD_ISSET (icmpsock, &rs))
- process_icmp_response ();
- if (0 == (++alt % 2))
- send_icmp_echo (&external);
- else
- send_udp ();
- }
- /* select failed (internal error or OS out of resources) */
- close (icmpsock);
- close (rawsock);
- close (udpsock);
- return 4;
+ static const struct GNUNET_GETOPT_CommandLineOption options[] = {
+ GNUNET_GETOPT_OPTION_END
+ };
+
+ if (GNUNET_OK !=
+ GNUNET_PROGRAM_run (argc, argv,
+ "gnunet-nat-server",
+ _("GNUnet NAT traversal test helper daemon"),
+ options,
+ &run, NULL))
+ return 1;
+ return 0;
}
struct GNUNET_RESOLVER_RequestHandle *hostname_dns;
/**
- * stdout pipe handle for the gnunet-nat-server process
+ * stdout pipe handle for the gnunet-helper-nat-server process
*/
struct GNUNET_DISK_PipeHandle *server_stdout;
/**
- * stdout file handle (for reading) for the gnunet-nat-server process
+ * stdout file handle (for reading) for the gnunet-helper-nat-server process
*/
const struct GNUNET_DISK_FileHandle *server_stdout_handle;
struct LocalAddressList *lal_tail;
/**
- * How long do we wait for restarting a crashed gnunet-nat-server?
+ * How long do we wait for restarting a crashed gnunet-helper-nat-server?
*/
struct GNUNET_TIME_Relative server_retry_delay;
/**
- * ID of select gnunet-nat-server stdout read task
+ * ID of select gnunet-helper-nat-server stdout read task
*/
GNUNET_SCHEDULER_TaskIdentifier server_read_task;
int enable_nat_client;
/**
- * Should we run the gnunet-nat-server?
+ * Should we run the gnunet-helper-nat-server?
*/
int enable_nat_server;
/**
- * Try to start the gnunet-nat-server (if it is not
+ * Try to start the gnunet-helper-nat-server (if it is not
* already running).
*
* @param h handle to NAT
* Add the given address to the list of 'local' addresses, thereby
* making it a 'legal' address for this peer to have. Set the
* port number in the process to the advertised port and possibly
- * also to zero (if we have the gnunet-nat-server).
+ * also to zero (if we have the gnunet-helper-nat-server).
*
* @param plugin the plugin
* @param src where did the local address originate from?
/**
- * Task that restarts the gnunet-nat-server process after a crash
+ * Task that restarts the gnunet-helper-nat-server process after a crash
* after a certain delay.
*
* @param cls the 'struct GNUNET_NAT_Handle'
/**
- * We have been notified that gnunet-nat-server has written something to stdout.
+ * We have been notified that gnunet-helper-nat-server has written something to stdout.
* Handle the output, then reschedule this function to be called again once
* more is available.
*
(1 != sscanf (port_start, "%d", &port)) ||
(-1 == inet_pton(AF_INET, mybuf, &sin_addr.sin_addr)) )
{
- /* should we restart gnunet-nat-server? */
+ /* should we restart gnunet-helper-nat-server? */
GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING,
"nat",
- _("gnunet-nat-server generated malformed address `%s'\n"),
+ _("gnunet-helper-nat-server generated malformed address `%s'\n"),
mybuf);
h->server_read_task
= GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL,
#if DEBUG_NAT
GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
"nat",
- "gnunet-nat-server read: %s:%d\n",
+ "gnunet-helper-nat-server read: %s:%d\n",
mybuf, port);
#endif
h->reversal_callback (h->callback_cls,
/**
- * Try to start the gnunet-nat-server (if it is not
+ * Try to start the gnunet-helper-nat-server (if it is not
* already running).
*
* @param h handle to NAT
GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
"nat"
"Starting %s at `%s'\n",
- "gnunet-nat-server",
+ "gnunet-helper-nat-server",
h->internal_address);
#endif
/* Start the server process */
h->server_proc = GNUNET_OS_start_process (NULL,
h->server_stdout,
- "gnunet-nat-server",
- "gnunet-nat-server",
+ "gnunet-helper-nat-server",
+ "gnunet-helper-nat-server",
h->internal_address,
NULL);
if (h->server_proc == NULL)
GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING,
"nat",
_("Failed to start %s\n"),
- "gnunet-nat-server");
+ "gnunet-helper-nat-server");
GNUNET_DISK_pipe_close (h->server_stdout);
h->server_stdout = NULL;
}
/* Test for SUID binaries */
if ( (h->behind_nat == GNUNET_YES) &&
(GNUNET_YES == h->enable_nat_server) &&
- (GNUNET_YES != check_gnunet_nat_binary("gnunet-nat-server")) )
+ (GNUNET_YES != check_gnunet_nat_binary("gnunet-helper-nat-server")) )
{
h->enable_nat_server = GNUNET_NO;
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
_("Configuration requires `%s', but binary is not installed properly (SUID bit not set). Option disabled.\n"),
- "gnunet-nat-server");
+ "gnunet-helper-nat-server");
}
if ( (GNUNET_YES == h->enable_nat_client) &&
- (GNUNET_YES != check_gnunet_nat_binary("gnunet-nat-client")) )
+ (GNUNET_YES != check_gnunet_nat_binary("gnunet-helper-nat-client")) )
{
h->enable_nat_client = GNUNET_NO;
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
_("Configuration requires `%s', but binary is not installed properly (SUID bit not set). Option disabled.\n"),
- "gnunet-nat-client");
+ "gnunet-helper-nat-client");
}
start_gnunet_nat_server (h);
/**
* We learned about a peer (possibly behind NAT) so run the
- * gnunet-nat-client to send dummy ICMP responses to cause
+ * gnunet-helper-nat-client to send dummy ICMP responses to cause
* that peer to connect to us (connection reversal).
*
* @param h NAT handle for us (largely used for configuration)
#if DEBUG_TCP_NAT
GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
"nat",
- _("Running gnunet-nat-client %s %s %u\n"),
+ _("Running gnunet-helper-nat-client %s %s %u\n"),
h->internal_address,
inet4,
(unsigned int) h->adv_port);
#endif
proc = GNUNET_OS_start_process (NULL,
NULL,
- "gnunet-nat-client",
- "gnunet-nat-client",
+ "gnunet-helper-nat-client",
+ "gnunet-helper-nat-client",
h->internal_address,
inet4,
port_as_string,
NULL);
if (NULL == proc)
return;
- /* we know that the gnunet-nat-client will terminate virtually
+ /* we know that the gnunet-helper-nat-client will terminate virtually
instantly */
GNUNET_OS_process_wait (proc);
GNUNET_OS_process_close (proc);
ret = (GNUNET_OK ==
GNUNET_PROGRAM_run (argc,
argv,
- "topology",
+ "gnunet-daemon-topology",
_("GNUnet topology control (maintaining P2P mesh and F2F constraints)"),
options,
&run, NULL)) ? 0 : 1;
endif
endif
+if LINUX
+install-exec-hook:
+ chown root:root $(bindir)/gnunet-transport-wlan-helper || true
+ chmod u+s $(bindir)/gnunet-transport-wlan-helper || true
+else
+install-exec-hook:
+endif
+
if !MINGW
UNIX_PLUGIN_LA = libgnunet_plugin_transport_unix.la
UNIX_PLUGIN_TEST = test_transport_api_unix
projects / oweals / gnunet.git / commitdiff