#define NAT_TRAV_PORT 22225
+/**
+ * Must match packet ID used by gnunet-helper-nat-server.c
+ */
+#define PACKET_ID 256
+
/**
* IPv4 header.
*/
ip_pkt.vers_ihl = 0x45;
ip_pkt.tos = 0;
ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons (256);
+ ip_pkt.id = htons (PACKET_ID);
ip_pkt.flags_frag_offset = 0;
ip_pkt.ttl = 128;
ip_pkt.proto = IPPROTO_ICMP;
}
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);
}
}
ip_pkt.vers_ihl = 0x45;
ip_pkt.tos = 0;
ip_pkt.pkt_len = htons (sizeof (packet));
- ip_pkt.id = htons (256);
+ ip_pkt.id = htons (PACKET_ID);
ip_pkt.flags_frag_offset = 0;
ip_pkt.ttl = IPDEFTTL;
ip_pkt.proto = IPPROTO_ICMP;
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;
}
-/**
- * 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;
- ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
- if (-1 == 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 */
+
+ /* 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 */