*
* - Christian Grothoff
* - Nathan Evans
+ * - Benjamin Kuperman (22 Aug 2010)
*/
#if HAVE_CONFIG_H
/* Just needed for HAVE_SOCKADDR_IN_SIN_LEN test macro! */
#else
#define _GNU_SOURCE
#endif
-#include <sys/types.h>
+#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/select.h>
#include <time.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
-#include <netinet/in.h>
+#include <netinet/in.h>
/**
* Should we print some debug output?
/**
* Port for UDP
- */
+ */
#define NAT_TRAV_PORT 22225
/**
/**
* IPv4 header.
*/
-struct ip_header
+struct ip_header
{
/**
- * Version (4 bits) + Internet header length (4 bits)
+ * Version (4 bits) + Internet header length (4 bits)
*/
uint8_t vers_ihl;
uint8_t ttl;
/**
- * Protocol
+ * Protocol
*/
uint8_t proto;
-
+
/**
* Header checksum
*/
uint32_t src_ip;
/**
- * Destination address
+ * Destination address
*/
uint32_t dst_ip;
};
/**
* Format of ICMP packet.
*/
-struct icmp_ttl_exceeded_header
+struct icmp_ttl_exceeded_header
{
uint8_t type;
* @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,
+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];
+ for (i=0;i<bytes/2;i++)
+ sum += data[i];
sum = (sum & 0xffff) + (sum >> 16);
sum = htons(0xffff - sum);
return sum;
struct sockaddr_in dst;
size_t off;
int err;
-
+
off = 0;
ip_pkt.vers_ihl = 0x45;
ip_pkt.tos = 0;
- ip_pkt.pkt_len = sizeof (packet);
- ip_pkt.id = 1;
+ 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.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,
+ ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt,
sizeof (struct ip_header)));
memcpy (&packet[off],
- &ip_pkt,
+ &ip_pkt,
sizeof (struct ip_header));
off += sizeof (struct ip_header);
icmp_echo.code = 0;
icmp_echo.checksum = 0;
icmp_echo.reserved = 0;
- icmp_echo.checksum = htons(calc_checksum((uint16_t*)&icmp_echo,
+ 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(struct sockaddr_in));
- if (err < 0)
+ 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)
+ else if (sizeof (packet) != err)
{
fprintf(stderr,
"Error: partial send of ICMP message\n");
/**
* Send a UDP message to the dummy IP.
- *
- * @param my_ip source address (our ip address)
*/
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
#endif
dst.sin_addr = dummy;
dst.sin_port = htons (NAT_TRAV_PORT);
- err = sendto(udpsock,
- NULL, 0, 0,
- (struct sockaddr*)&dst,
+ err = sendto(udpsock,
+ NULL, 0, 0,
+ (struct sockaddr*)&dst,
sizeof(dst));
- if (err < 0)
+ if (err < 0)
{
#if VERBOSE
fprintf(stderr,
"sendto failed: %s\n", strerror(errno));
#endif
}
- else if (0 != err)
+ else if (0 != err)
{
fprintf(stderr,
"Error: partial send of ICMP message\n");
ssize_t have;
struct in_addr source_ip;
struct ip_header ip_pkt;
- struct icmp_ttl_exceeded_header icmp_pkt;
- struct icmp_echo_header icmp_echo_pkt;
+ struct icmp_ttl_exceeded_header icmp_ttl;
+ struct icmp_echo_header icmp_echo;
struct udp_header udp_pkt;
size_t off;
- uint32_t port;
-
+ uint16_t port;
+
have = read (icmpsock, buf, sizeof (buf));
if (-1 == have)
{
fprintf (stderr,
"Error reading raw socket: %s\n",
strerror (errno));
- return;
+ return;
}
#if VERBOSE
fprintf (stderr,
"Received message of %u bytes\n",
(unsigned int) have);
#endif
- if (have < sizeof (struct ip_header) + sizeof (struct icmp_ttl_exceeded_header) + sizeof (struct ip_header) )
+ 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],
+ &buf[off],
sizeof (struct ip_header));
off += sizeof (struct ip_header);
- memcpy(&source_ip,
- &ip_pkt.src_ip,
+ memcpy(&source_ip,
+ &ip_pkt.src_ip,
sizeof (source_ip));
- memcpy (&icmp_pkt,
- &buf[off],
+ memcpy (&icmp_ttl,
+ &buf[off],
sizeof (struct icmp_ttl_exceeded_header));
off += sizeof (struct icmp_ttl_exceeded_header);
- if ( (ICMP_TIME_EXCEEDED != icmp_pkt.type) ||
- (0 != icmp_pkt.code) )
+ 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) +
+ 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_pkt,
+ memcpy (&icmp_echo,
&buf[off],
sizeof (struct icmp_echo_header));
- port = (uint16_t) htonl (icmp_echo_pkt.reserved);
+ port = (uint16_t) ntohl (icmp_echo.reserved);
break;
case IPPROTO_UDP:
- if (have != (sizeof (struct ip_header) * 2 +
- sizeof (struct icmp_ttl_exceeded_header) +
+ if (have != (sizeof (struct ip_header) * 2 +
+ sizeof (struct icmp_ttl_exceeded_header) +
sizeof (struct udp_header)) )
{
/* malformed */
memcpy (&udp_pkt,
&buf[off],
sizeof (struct udp_header));
- port = ntohs (udp_pkt.crc);
port = ntohs (udp_pkt.length);
break;
- default:
+ default:
/* different type than what we want */
return;
}
sizeof (buf)));
else
fprintf (stdout,
- "%s:%d\n",
+ "%s:%u\n",
inet_ntop (AF_INET,
&source_ip,
buf,
- sizeof (buf)),
- port);
+ sizeof (buf)),
+ (unsigned int) port);
fflush (stdout);
}
"Error opening RAW socket: %s\n",
strerror (errno));
return -1;
- }
- if (ret >= FD_SETSIZE)
+ }
+ if (ret >= FD_SETSIZE)
{
fprintf (stderr,
"Socket number too large (%d > %u)\n",
"Error opening RAW socket: %s\n",
strerror (errno));
return -1;
- }
- if (-1 == setsockopt(ret,
- SOL_SOCKET,
+ }
+ if (-1 == setsockopt(ret,
+ SOL_SOCKET,
SO_BROADCAST,
(char *)&one, sizeof(one)))
{
close (ret);
return -1;
}
- if (-1 == setsockopt(ret,
- IPPROTO_IP,
+ if (-1 == setsockopt(ret,
+ IPPROTO_IP,
IP_HDRINCL,
(char *)&one, sizeof(one)))
{
/**
* Create a UDP socket for writinging.
*
+ * @param my_ip source address (our ip address)
* @return -1 on error
*/
static int
strerror (errno));
return -1;
}
- memset (&addr,
- 0,
+ memset (&addr,
+ 0,
sizeof (addr));
addr.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
int
-main (int argc,
+main (int argc,
char *const *argv)
{
struct in_addr external;
if (1 != inet_pton (AF_INET, argv[1], &external))
{
fprintf (stderr,
- "Error parsing IPv4 address: %s\n",
- strerror (errno));
+ "Error parsing IPv4 address: %s\n",
+ strerror (errno));
return 1;
}
- if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
+ if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy))
{
fprintf (stderr,
"Internal error converting dummy IP to binary.\n");
}
if (-1 == (icmpsock = make_icmp_socket()))
{
- return 3;
+ return 3;
}
if (-1 == (rawsock = make_raw_socket()))
{
close (icmpsock);
- return 3;
+ return 3;
}
uid = getuid ();
if (0 != setresuid (uid, uid, uid))
{
fprintf (stderr,
"Failed to setresuid: %s\n",
- strerror (errno));
+ strerror (errno));
/* not critical, continue anyway */
}
if (-1 == (udpsock = make_udp_socket(&external)))
{
close (icmpsock);
close (rawsock);
- return 3;
+ 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;
+ tv.tv_usec = ICMP_SEND_FREQUENCY_MS * 1000;
if (-1 == select (icmpsock + 1, &rs, NULL, NULL, &tv))
{
if (errno == EINTR)
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 ();
+ 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);
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