#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;
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)));
+ 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);
/* 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.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.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)));
+ 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);
dst.sin_len = sizeof (struct sockaddr_in);
#endif
dst.sin_addr = *other;
- err = sendto (rawsock,
- packet,
- sizeof (packet), 0, (struct sockaddr *) &dst, sizeof (dst));
+ err =
+ sendto (rawsock, packet, sizeof (packet), 0, (struct sockaddr *) &dst,
+ sizeof (dst));
if (err < 0)
{
fprintf (stderr, "sendto failed: %s\n", strerror (errno));
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.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)));
+ 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);
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.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)));
+ 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.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)));
+ 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)));
+ 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 */
dst.sin_len = sizeof (struct sockaddr_in);
#endif
dst.sin_addr = *other;
- err = sendto (rawsock,
- packet,
- sizeof (packet), 0, (struct sockaddr *) &dst, sizeof (dst));
+ err =
+ sendto (rawsock, packet, sizeof (packet), 0, (struct sockaddr *) &dst,
+ sizeof (dst));
if (err < 0)
{
fprintf (stderr, "sendto failed: %s\n", strerror (errno));
}
-/**
- * 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, "Error opening RAW socket: %s\n", strerror (errno));
- return -1;
+ fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
+ global_ret = 1;
+ goto cleanup;
}
- if (0 != setsockopt (ret, SOL_SOCKET, SO_BROADCAST,
- (char *) &one, sizeof (one)))
+#else
+ if (0 != (setuid (uid) | seteuid (uid)))
+ {
+ 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 (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)))
+ if (0 !=
+ 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);
+ global_ret = 0;
+ cleanup:
+ if (-1 != rawsock)
+ (void) close (rawsock);
return 0;
}
projects / oweals / gnunet.git / blobdiff