/*
This file is part of GNUnet.
- (C) 2010 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2010 GNUnet e.V.
- 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 free software: you can redistribute it and/or modify it
+ under the terms of the GNU Affero General Public License as published
+ by the Free Software Foundation, either version 3 of the License,
+ 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.
+ Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
- 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.
+ SPDX-License-Identifier: AGPL3.0-or-later
*/
/**
#include <netinet/ip_icmp.h>
#include <netinet/in.h>
+/* The following constant is missing from FreeBSD 9.2 */
+#ifndef ICMP_TIME_EXCEEDED
+#define ICMP_TIME_EXCEEDED 11
+#endif
+
+/**
+ * Call memcpy() but check for @a n being 0 first. In the latter
+ * case, it is now safe to pass NULL for @a src or @a dst.
+ * Unlike traditional memcpy(), returns nothing.
+ *
+ * @param dst destination of the copy, may be NULL if @a n is zero
+ * @param src source of the copy, may be NULL if @a n is zero
+ * @param n number of bytes to copy
+ */
+#define GNUNET_memcpy(dst,src,n) do { if (0 != n) { (void) memcpy (dst,src,n); } } while (0)
+
/**
* Must match IP given in the server.
*/
#define NAT_TRAV_PORT 22225
+/**
+ * Must match packet ID used by gnunet-helper-nat-server.c
+ */
+#define PACKET_ID 256
+
/**
* IPv4 header.
*/
off = 0;
ip_pkt.vers_ihl = 0x45;
ip_pkt.tos = 0;
+#ifdef FREEBSD
+ ip_pkt.pkt_len = sizeof (packet); /* Workaround PR kern/21737 */
+#else
ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons (256);
+#endif
+ ip_pkt.id = htons (PACKET_ID);
ip_pkt.flags_frag_offset = 0;
ip_pkt.ttl = 128;
ip_pkt.proto = IPPROTO_ICMP;
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));
+ GNUNET_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));
+ GNUNET_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.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));
+ GNUNET_memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
off += sizeof (struct ip_header);
/* build UDP header */
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));
+ GNUNET_memcpy (&packet[off],
+ &udp_pkt,
+ sizeof (struct udp_header));
off += sizeof (struct udp_header);
/* set ICMP 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));
+ GNUNET_memcpy (&packet[sizeof (struct ip_header)],
+ &icmp_pkt,
+ sizeof (struct icmp_ttl_exceeded_header));
memset (&dst, 0, sizeof (dst));
dst.sin_family = AF_INET;
}
else if (sizeof (packet) != (size_t) err)
{
- fprintf (stderr, "Error: partial send of ICMP message\n");
+ fprintf (stderr, "Error: partial send of ICMP message with size %lu\n", (unsigned long) off);
}
}
off = 0;
ip_pkt.vers_ihl = 0x45;
ip_pkt.tos = 0;
+#ifdef FREEBSD
+ ip_pkt.pkt_len = sizeof (packet); /* Workaround PR kern/21737 */
+#else
ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons (256);
+#endif
+ ip_pkt.id = htons (PACKET_ID);
ip_pkt.flags_frag_offset = 0;
ip_pkt.ttl = IPDEFTTL;
ip_pkt.proto = IPPROTO_ICMP;
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));
+ GNUNET_memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
off = sizeof (ip_pkt);
/* icmp reply: 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));
+ GNUNET_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.tos = 0;
ip_pkt.pkt_len =
htons (sizeof (struct ip_header) + sizeof (struct icmp_echo_header));
- ip_pkt.id = htons (256);
+ ip_pkt.id = htons (PACKET_ID);
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.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));
+ GNUNET_memcpy (&packet[off],
+ &ip_pkt,
+ sizeof (struct ip_header));
off += sizeof (struct ip_header);
icmp_echo.type = ICMP_ECHO;
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));
+ ((uint16_t *) &icmp_echo, sizeof (struct icmp_echo_header)));
+ GNUNET_memcpy (&packet[off],
+ &icmp_echo,
+ sizeof (struct icmp_echo_header));
/* no go back to calculate ICMP packet checksum */
off = sizeof (struct ip_header);
((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));
+ GNUNET_memcpy (&packet[off],
+ &icmp_ttl,
+ sizeof (struct icmp_ttl_exceeded_header));
/* prepare for transmission */
memset (&dst, 0, sizeof (dst));
}
-/**
- * Create an ICMP raw socket for writing.
- *
- * @return -1 on error
- */
-static int
-make_raw_socket ()
+int
+main (int argc, char *const *argv)
{
const int one = 1;
- int ret;
+ struct in_addr external;
+ struct in_addr target;
+ uid_t uid;
+ unsigned int p;
+ int raw_eno;
+ int global_ret;
+
+ /* Create an ICMP raw socket for writing (only operation that requires root) */
+ rawsock = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
+ raw_eno = errno; /* for later error checking */
- ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
- if (-1 == ret)
+ /* now drop root privileges */
+ uid = getuid ();
+#ifdef HAVE_SETRESUID
+ if (0 != setresuid (uid, uid, uid))
+ {
+ fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
+ global_ret = 1;
+ goto cleanup;
+ }
+#else
+ if (0 != (setuid (uid) | seteuid (uid)))
{
- fprintf (stderr, "Error opening RAW socket: %s\n", strerror (errno));
- return -1;
+ fprintf (stderr, "Failed to setuid: %s\n", strerror (errno));
+ global_ret = 2;
+ goto cleanup;
+ }
+#endif
+ if (-1 == rawsock)
+ {
+ fprintf (stderr, "Error opening RAW socket: %s\n", strerror (raw_eno));
+ global_ret = 3;
+ goto cleanup;
}
if (0 !=
- setsockopt (ret, SOL_SOCKET, SO_BROADCAST, (char *) &one, sizeof (one)))
+ setsockopt (rawsock, SOL_SOCKET, SO_BROADCAST, (char *) &one, sizeof (one)))
{
fprintf (stderr, "setsockopt failed: %s\n", strerror (errno));
- close (ret);
- return -1;
+ global_ret = 4;
+ goto cleanup;
}
if (0 !=
- setsockopt (ret, IPPROTO_IP, IP_HDRINCL, (char *) &one, sizeof (one)))
+ setsockopt (rawsock, IPPROTO_IP, IP_HDRINCL, (char *) &one, sizeof (one)))
{
fprintf (stderr, "setsockopt failed: %s\n", strerror (errno));
- close (ret);
- return -1;
+ global_ret = 5;
+ goto cleanup;
}
- 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;
+ global_ret = 6;
+ goto cleanup;
}
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;
+ global_ret = 7;
+ goto cleanup;
}
if ((1 != sscanf (argv[3], "%u", &p)) || (0 == p) || (0xFFFF < p))
{
fprintf (stderr, "Error parsing port value `%s'\n", argv[3]);
- return 1;
+ global_ret = 8;
+ goto cleanup;
}
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 */
+ global_ret = 9;
+ goto cleanup;
}
send_icmp (&external, &target);
send_icmp_udp (&external, &target);
- close (rawsock);
- return 0;
+ global_ret = 0;
+ cleanup:
+ if (-1 != rawsock)
+ (void) close (rawsock);
+ return global_ret;
}
/* end of gnunet-helper-nat-client.c */
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