Ref: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=236635
Hi,
I cobbled a patch together this afternoon that seems to do the job.
Let me know how you get along with it. Not fully tested with IPv6, but
it seems to do the right things (from an 'strace').
Cheers
--
Alexander Clouter
.sigmonster says: May not be combined with other discounts.
diff -u -r nc6-1.0.orig/docs/nc6.1.in nc6-1.0/docs/nc6.1.in
--- nc6-1.0.orig/docs/nc6.1.in 2005-08-18 05:56:12.000000000 +0100
+++ nc6-1.0/docs/nc6.1.in 2009-03-11 16:20:55.838644858 +0000
@@ -117,6 +117,11 @@
.I \--no-reuseaddr
Disables the SO_REUSEADDR socket option (this is only useful in listen mode).
.TP 13
+.I \-T, \--ttl=TTL
+Set's the IP TTL of the packets leaving (this is only useful in connect mode).
+This is mainly useful for multicast, otherwise packets will often leave with
+the OS default of 1, making it rarely useful.
+.TP 13
.I \--nru=BYTES
Set the miNimum Receive Unit for the remote endpoint (network receives). Note
that this does not mean that every network read will get the specified number
diff -u -r nc6-1.0.orig/src/afindep.c nc6-1.0/src/afindep.c
--- nc6-1.0.orig/src/afindep.c 2006-01-19 22:46:23.000000000 +0000
+++ nc6-1.0/src/afindep.c 2009-03-11 16:15:54.746112636 +0000
@@ -64,6 +64,9 @@
struct addrinfo *res = NULL, *ptr;
bool connect_attempted = false;
char name_buf[AI_STR_SIZE];
+ const connection_attributes_t *attrs =
+ *((const connection_attributes_t **)hdata);
+ int on;
/* make sure arguments are valid and preconditions are respected */
assert(hints != NULL);
@@ -90,6 +93,23 @@
/* only accept results we can handle */
if (skip_address(ptr) == true) continue;
+ if (ptr->ai_socktype == SOCK_STREAM) {
+ if (ptr->ai_family == PF_INET) {
+ if (IN_MULTICAST(ntohl(((struct sockaddr_in *)(ptr->ai_addr))->sin_addr.s_addr))) {
+ warning("socket type STREAM and multicast bad, udp only!");
+ return -1;
+ }
+ }
+#ifdef ENABLE_IPV6
+ else if (ptr->ai_family == PF_INET6) {
+ if (IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)(ptr->ai_addr))->sin6_addr)) {
+ warning("socket type STREAM and multicast bad, udp only!");
+ return -1;
+ }
+ }
+#endif
+ }
+
/* we are going to try to connect to this address */
connect_attempted = true;
@@ -182,6 +202,28 @@
freeaddrinfo(src_res);
}
+ /* setup the ttl */
+ if ((on = ca_ttl(attrs)) > -1) {
+ if ( ptr->ai_family == PF_INET ) {
+ if (IN_MULTICAST(ntohl(((struct sockaddr_in *)(ptr->ai_addr))->sin_addr.s_addr))) {
+ setsockopt(fd, SOL_IP, IP_MULTICAST_TTL, &on, sizeof(on));
+ }
+ else {
+ setsockopt(fd, SOL_IP, IP_TTL, &on, sizeof(on));
+ }
+ }
+#ifdef ENABLE_IPV6
+ else if ( ptr->ai_family == PF_INET6 ) {
+ if (IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)(ptr->ai_addr))->sin6_addr)) {
+ setsockopt(fd, SOL_IPV6, IPV6_MULTICAST_HOPS, &on, sizeof(on));
+ }
+ else {
+ setsockopt(fd, SOL_IPV6, IPV6_UNICAST_HOPS, &on, sizeof(on));
+ }
+ }
+#endif
+ }
+
/* attempt the connection */
err = connect_with_timeout(fd,
ptr->ai_addr, ptr->ai_addrlen, timeout);
@@ -250,7 +292,10 @@
{
int nfd, i, fd, err, maxfd = -1;
struct addrinfo *res = NULL, *ptr;
+ int off = 0;
+ struct ip_mreq mreq;
#ifdef ENABLE_IPV6
+ struct ipv6_mreq mreq6;
bool set_ipv6_only = false;
bool bound_ipv6_any = false;
#endif
@@ -327,7 +372,24 @@
/* only accept results we can handle */
if (skip_address(ptr) == true) continue;
-
+
+ if (ptr->ai_socktype == SOCK_STREAM) {
+ if (ptr->ai_family == PF_INET) {
+ if (IN_MULTICAST(ntohl(((struct sockaddr_in *)(ptr->ai_addr))->sin_addr.s_addr))) {
+ warning("socket type STREAM and multicast bad, udp only!");
+ return -1;
+ }
+ }
+#ifdef ENABLE_IPV6
+ else if (ptr->ai_family == PF_INET6) {
+ if (IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)(ptr->ai_addr))->sin6_addr)) {
+ warning("socket type STREAM and multicast bad, udp only!");
+ return -1;
+ }
+ }
+#endif
+ }
+
/* create the socket */
fd = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
if (fd < 0) {
@@ -414,6 +476,27 @@
FD_SET(fd, &accept_fdset);
maxfd = MAX(maxfd, fd);
nfd++;
+
+ if (ptr->ai_family == PF_INET) {
+ if (IN_MULTICAST(ntohl(((struct sockaddr_in *)(ptr->ai_addr))->sin_addr.s_addr))) {
+ memset(&mreq, 0, sizeof(mreq));
+ mreq.imr_multiaddr = ((struct sockaddr_in *)(ptr->ai_addr))->sin_addr;
+ mreq.imr_interface.s_addr = INADDR_ANY;
+ setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
+ setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP, &off, sizeof(off));
+ }
+ }
+#ifdef ENABLE_IPV6
+ else if (ptr->ai_family == PF_INET6) {
+ if (IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)(ptr->ai_addr))->sin6_addr)) {
+ memset(&mreq6, 0, sizeof(mreq6));
+ mreq6.ipv6mr_multiaddr = ((struct sockaddr_in6 *)(ptr->ai_addr))->sin6_addr;
+ mreq6.ipv6mr_interface = 0;
+ setsockopt(fd, SOL_IPV6, IPV6_JOIN_GROUP, &mreq6, sizeof(mreq));
+ setsockopt(fd, SOL_IPV6, IPV6_MULTICAST_LOOP, &off, sizeof(off));
+ }
+ }
+#endif
}
freeaddrinfo(res);
diff -u -r nc6-1.0.orig/src/connection.h nc6-1.0/src/connection.h
--- nc6-1.0.orig/src/connection.h 2006-01-19 22:46:23.000000000 +0000
+++ nc6-1.0/src/connection.h 2009-03-11 14:13:36.647607520 +0000
@@ -56,6 +56,7 @@
sock_protocol_t protocol;
address_t remote_address;
address_t local_address;
+ int ttl;
int flags;
size_t buffer_size;
size_t remote_mtu;
@@ -104,6 +105,9 @@
#define ca_set_flag(CA, FLG) ((CA)->flags |= (FLG))
#define ca_clear_flag(CA, FLG) ((CA)->flags &= ~(FLG))
+#define ca_ttl(CA) ((CA)->ttl)
+#define ca_set_ttl(CA, SZ) ((CA)->ttl = (SZ))
+
#define ca_buffer_size(CA) ((CA)->buffer_size)
#define ca_set_buffer_size(CA, SZ) ((CA)->buffer_size = (SZ))
diff -u -r nc6-1.0.orig/src/parser.c nc6-1.0/src/parser.c
--- nc6-1.0.orig/src/parser.c 2006-01-19 22:46:23.000000000 +0000
+++ nc6-1.0/src/parser.c 2009-03-11 14:15:52.496481958 +0000
@@ -109,7 +109,9 @@
{"bluetooth", no_argument, NULL, 'b'},
#define OPT_SCO 24
{"sco", no_argument, NULL, 0 },
-#define OPT_MAX 25
+#define OPT_TTL 25
+ {"ttl", required_argument, NULL, 'T'},
+#define OPT_MAX 26
{0, 0, 0, 0}
};
@@ -142,6 +144,7 @@
int remote_hold_timeout = 0;
int remote_mtu = 0;
int remote_nru = 0;
+ int ttl = -1;
int buffer_size = 0;
int sndbuf_size = 0;
int rcvbuf_size = 0;
@@ -160,7 +163,7 @@
_verbosity_level = 0;
/* option recognition loop */
- while ((c = getopt_long(argc, argv, "46be:hlnp:q:s:uvw:xX",
+ while ((c = getopt_long(argc, argv, "46beT:hlnp:q:s:uvw:xX",
long_options, &option_index)) >= 0)
{
switch (c) {
@@ -296,6 +299,14 @@
case 'X':
rev_file_transfer = true;
break;
+ case 'T':
+ assert(optarg != NULL);
+ if (safe_atoi(optarg, &ttl))
+ fatal(_("invalid argument to "
+ "--ttl"));
+ if (ttl < -1 || ttl > 255 )
+ fatal(_("ttl can only be set between 0 to 255"));
+ break;
case '?':
print_usage(stderr);
exit(EXIT_FAILURE);
@@ -446,6 +457,11 @@
fatal(_("--continuous option "
"must be used with --exec"));
}
+
+ if (ttl != -1) {
+ warning(_("setting ttl in listen mode "
+ "is meaningless, ignoring"));
+ }
} else {
/* check port has been specified (except with sco) */
if (remote_address.address == NULL ||
@@ -508,11 +524,12 @@
if (set_local_hold_timeout == true)
ca_set_local_hold_timeout(attrs, local_hold_timeout);
- /* setup mtu, nru, and buffer sizes if they were specified */
+ /* setup mtu, nru, ttl, and buffer sizes if they were specified */
if (remote_mtu > 0)
ca_set_remote_MTU(attrs, remote_mtu);
if (remote_nru > 0)
ca_set_remote_NRU(attrs, remote_nru);
+ ca_set_ttl(attrs, ttl);
if (buffer_size > 0)
ca_set_buffer_size(attrs, buffer_size);
if (sndbuf_size > 0)
@@ -603,6 +620,7 @@
fprintf(fp, " -x, --transfer %s\n", _("File transfer mode"));
fprintf(fp, " -X, --rev-transfer %s\n",
_("File transfer mode (reverse direction)"));
+ fprintf(fp, " -T, --ttl=TTL %s\n", _("TTL of outgoing IP packet"));
fprintf(fp, "\n");
}
