Merge branch 'master' of git://tinc-vpn.org/tinc into 1.1

Conflicts:
	src/net.c
	src/net_packet.c
	src/net_socket.c

diff --git a/doc/tinc.conf.5.in b/doc/tinc.conf.5.in
index 47cf82e5c7c0d06817f8fffe9ba09f671bd60ef8..99b987772ad0157ded52790323888eb1c1bd1000 100644 (file)
--- a/doc/tinc.conf.5.in
+++ b/doc/tinc.conf.5.in
@@ -335,6 +335,18 @@ This option controls the period the encryption keys used to encrypt the data are
 It is common practice to change keys at regular intervals to make it even harder for crackers,
 even though it is thought to be nearly impossible to crack a single key.
 
+.It Va LocalDiscovery Li = yes | no Po no Pc Bq experimental
+When enabled,
+.Nm tinc
+will try to detect peers that are on the same local network.
+This will allow direct communication using LAN addresses, even if both peers are behind a NAT
+and they only ConnectTo a third node outside the NAT,
+which normally would prevent the peers from learning each other's LAN address.
+
+.Pp
+Currently, local discovery is implemented by sending broadcast packets to the LAN during path MTU discovery.
+This feature may not work in all possible situations.
+
 .It Va MACExpire Li = Ar seconds Pq 600
 This option controls the amount of time MAC addresses are kept before they are removed.
 This only has effect when

diff --git a/doc/tinc.texi b/doc/tinc.texi
index 4d9f233ac7a1c4e6ad6073ea3b9342dd2ce3f2a6..0c470123ae47168ba5d039d966791263114b1354 100644 (file)
--- a/doc/tinc.texi
+++ b/doc/tinc.texi
@@ -961,6 +961,16 @@ Depending on the operating system and the type of device this may or may not act
 Under Windows, this variable is used to select which network interface will be used.
 If you specified a Device, this variable is almost always already correctly set.
 
+@cindex LocalDiscovery
+@item LocalDiscovery = <yes | no> (no) [experimental]
+When enabled, tinc will try to detect peers that are on the same local network.
+This will allow direct communication using LAN addresses, even if both peers are behind a NAT
+and they only ConnectTo a third node outside the NAT,
+which normally would prevent the peers from learning each other's LAN address.
+
+Currently, local discovery is implemented by sending broadcast packets to the LAN during path MTU discovery.
+This feature may not work in all possible situations.
+
 @cindex Mode
 @item Mode = <router|switch|hub> (router)
 This option selects the way packets are routed to other daemons.

diff --git a/src/graph.c b/src/graph.c
index bb55dfdcba1c821d25fcf1f27e4c81fc5478fb7f..42157b0a994b8cc29630eed36559dac9688e6cb1 100644 (file)
--- a/src/graph.c
+++ b/src/graph.c
@@ -239,6 +239,7 @@ void sssp_bfs(void) {
        myself->status.visited = true;
        myself->status.indirect = false;
        myself->nexthop = myself;
+       myself->prevedge = NULL;
        myself->via = myself;
        list_insert_head(todo_list, myself);
 
@@ -279,6 +280,7 @@ void sssp_bfs(void) {
                        e->to->status.visited = true;
                        e->to->status.indirect = indirect;
                        e->to->nexthop = (n->nexthop == myself) ? e->to : n->nexthop;
+                       e->to->prevedge = e;
                        e->to->via = indirect ? n->via : e->to;
                        e->to->options = e->options;
 

diff --git a/src/net.h b/src/net.h
index c511a5fc8342f6084525bbbbe7300afb63c1ca85..6ca13d488a307cdea812521c88c4568009fcdfa8 100644 (file)
--- a/src/net.h
+++ b/src/net.h
@@ -109,6 +109,7 @@ extern int maxoutbufsize;
 extern int seconds_till_retry;
 extern int addressfamily;
 extern unsigned replaywin;
+extern bool localdiscovery;
 
 extern listen_socket_t listen_socket[MAXSOCKETS];
 extern int listen_sockets;

diff --git a/src/net_packet.c b/src/net_packet.c
index f7d8640300a6bc5065b572e0828446e9b3cb7c0a..64b0f8e8490adb7d5f0a06c2c99f6fcf39db2e64 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -62,13 +62,21 @@ static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999
 static void send_udppacket(node_t *, vpn_packet_t *);
 
 unsigned replaywin = 16;
+bool localdiscovery = false;
 
 #define MAX_SEQNO 1073741824
 
-// mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
-// mtuprobes ==    31: sleep pinginterval seconds
-// mtuprobes ==    32: send 1 burst, sleep pingtimeout second
-// mtuprobes ==    33: no response from other side, restart PMTU discovery process
+/* mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
+   mtuprobes ==    31: sleep pinginterval seconds
+   mtuprobes ==    32: send 1 burst, sleep pingtimeout second
+   mtuprobes ==    33: no response from other side, restart PMTU discovery process
+
+   Probes are sent in batches of three, with random sizes between the lower and
+   upper boundaries for the MTU thus far discovered.
+
+   In case local discovery is enabled, a fourth packet is added to each batch,
+   which will be broadcast to the local network.
+*/
 
 static void send_mtu_probe_handler(int fd, short events, void *data) {
        node_t *n = data;
@@ -119,7 +127,7 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
                timeout = pingtimeout;
        }
 
-       for(i = 0; i < 3; i++) {
+       for(i = 0; i < 3 + localdiscovery; i++) {
                if(n->maxmtu <= n->minmtu)
                        len = n->maxmtu;
                else
@@ -131,7 +139,7 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
                memset(packet.data, 0, 14);
                randomize(packet.data + 14, len - 14);
                packet.len = len;
-               packet.priority = 0;
+               packet.priority = i < 3 ? 0 : -1;
 
                ifdebug(TRAFFIC) logger(LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
 
@@ -473,6 +481,29 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
        /* Send the packet */
 
+       struct sockaddr *sa;
+       socklen_t sl;
+       int sock;
+
+       /* Overloaded use of priority field: -1 means local broadcast */
+
+       if(origpriority == -1 && n->prevedge) {
+               struct sockaddr_in in;
+               in.sin_family = AF_INET;
+               in.sin_addr.s_addr = -1;
+               in.sin_port = n->prevedge->address.in.sin_port;
+               sa = (struct sockaddr *)&in;
+               sl = sizeof in;
+               sock = 0;
+       } else {
+               if(origpriority == -1)
+                       origpriority = 0;
+
+               sa = &(n->address.sa);
+               sl = SALEN(n->address.sa);
+               sock = n->sock;
+       }
+
 #if defined(SOL_IP) && defined(IP_TOS)
        if(priorityinheritance && origpriority != priority
           && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
@@ -483,7 +514,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        }
 #endif
 
-       if(sendto(listen_socket[n->sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa)) < 0 && !sockwouldblock(sockerrno)) {
+       if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
                if(sockmsgsize(sockerrno)) {
                        if(n->maxmtu >= origlen)
                                n->maxmtu = origlen - 1;
@@ -593,6 +624,7 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
        if(hard)
                last_hard_try = now;
 
+       last_hard_try = now;
        return n;
 }
 

diff --git a/src/net_setup.c b/src/net_setup.c
index 207ce42543b4c9da1c542aa4f7484b580953a425..d292d850ced2f43d3f187ace41d28a953b6e47fb 100644 (file)
--- a/src/net_setup.c
+++ b/src/net_setup.c
@@ -433,6 +433,7 @@ static bool setup_myself(void) {
        get_config_bool(lookup_config(config_tree, "DirectOnly"), &directonly);
        get_config_bool(lookup_config(config_tree, "StrictSubnets"), &strictsubnets);
        get_config_bool(lookup_config(config_tree, "TunnelServer"), &tunnelserver);
+       get_config_bool(lookup_config(config_tree, "LocalDiscovery"), &localdiscovery);
        strictsubnets |= tunnelserver;
 
        if(get_config_string(lookup_config(config_tree, "Mode"), &mode)) {

diff --git a/src/net_socket.c b/src/net_socket.c
index 730cf6b8e56f5f00ffce0fa12ec34e6a7334aedd..282066976b271c23e827e7f7149daa2486bf3917 100644 (file)
--- a/src/net_socket.c
+++ b/src/net_socket.c
@@ -210,6 +210,7 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
 
        option = 1;
        setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof option);
+       setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof option);
 
        if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
                logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));

diff --git a/src/node.h b/src/node.h
index 4464011fc1f60e3ad94a355510432cb6039b1b69..e86aa6a012e58523c4b9c74b7f71c5024d9d602d 100644 (file)
--- a/src/node.h
+++ b/src/node.h
@@ -64,6 +64,7 @@ typedef struct node_t {
 
        int distance;
        struct node_t *nexthop;                 /* nearest node from us to him */
+       struct edge_t *prevedge;                /* nearest node from him to us */
        struct node_t *via;                     /* next hop for UDP packets */
 
        splay_tree_t *subnet_tree;              /* Pointer to a tree of subnets belonging to this node */