Try all known addresses of node during the PMTU discovery phase.

This helps in situations where some nodes have IPv6 and others have not.

diff --git a/src/graph.c b/src/graph.c
index 86b62a5..48310bc 100644 (file)
--- a/src/graph.c
+++ b/src/graph.c
@@ -208,6 +208,7 @@ static void check_reachability(void) {
                        }
                        n->last_req_key = 0;
 
+                       n->status.udp_confirmed = false;
                        n->maxmtu = MTU;
                        n->minmtu = 0;
                        n->mtuprobes = 0;

diff --git a/src/info.c b/src/info.c
index 93be24e..ed4dc82 100644 (file)
--- a/src/info.c
+++ b/src/info.c
@@ -111,6 +111,8 @@ static int info_node(int fd, const char *item) {
                printf(" indirect");
        if(status.sptps)
                printf(" sptps");
+       if(status.udp_confirmed)
+               printf(" udp_confirmed");
        printf("\n");
 
        printf("Options:     ");

diff --git a/src/net_packet.c b/src/net_packet.c
index 88d791d..6bb2fca 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -97,6 +97,7 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
                }
 
                logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
+               n->status.udp_confirmed = false;
                n->mtuprobes = 1;
                n->minmtu = 0;
                n->maxmtu = MTU;
@@ -166,6 +167,8 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
                packet->data[0] = 1;
                send_udppacket(n, packet);
        } else {
+               n->status.udp_confirmed = true;
+
                if(n->mtuprobes > 30) {
                        if(n->minmtu)
                                n->mtuprobes = 30;
@@ -528,42 +531,77 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
                inpkt->len += digest_length(&n->outdigest);
        }
 
-       /* Determine which socket we have to use */
-
-       if(n->address.sa.sa_family != listen_socket[n->sock].sa.sa.sa_family) {
-               for(int sock = 0; sock < listen_sockets; sock++) {
-                       if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family) {
-                               n->sock = sock;
-                               break;
-                       }
-               }
-       }
-
        /* Send the packet */
 
-       struct sockaddr *sa;
-       socklen_t sl;
+       sockaddr_t *sa;
        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;
+               sockaddr_t broadcast;
+               broadcast.in.sin_family = AF_INET;
+               broadcast.in.sin_addr.s_addr = -1;
+               broadcast.in.sin_port = n->prevedge->address.in.sin_port;
+               sa = &broadcast;
                sock = 0;
        } else {
                if(origpriority == -1)
                        origpriority = 0;
 
-               sa = &(n->address.sa);
-               sl = SALEN(n->address.sa);
-               sock = n->sock;
+               if(n->status.udp_confirmed) {
+                       /* Address of this node is confirmed, so use it. */
+                       sa = &n->address;
+                       sock = n->sock;
+               } else {
+                       /* Otherwise, go through the list of known addresses of
+                          this node. The first address we try is always the
+                          one in n->address; that could be set to the node's
+                          reflexive UDP address discovered during key
+                          exchange. The other known addresses are those found
+                          in edges to this node. */
+
+                       static unsigned int i;
+                       int j = 0;
+                       edge_t *candidate = NULL;
+
+                       if(i) {
+                               for splay_each(edge_t, e, edge_weight_tree) {
+                                       if(e->to != n)
+                                               continue;
+                                       j++;
+                                       if(!candidate || j == i)
+                                               candidate = e;
+                               }
+                       }
+
+                       if(!candidate) {
+                               sa = &n->address;
+                               sock = n->sock;
+                       } else {
+                               sa = &candidate->address;
+                               sock = rand() % listen_sockets;
+                       }
+
+                       if(i++)
+                               if(i > j)
+                                       i = 0;
+               }
        }
 
+       /* Determine which socket we have to use */
+
+       if(sa->sa.sa_family != listen_socket[sock].sa.sa.sa_family)
+               for(sock = 0; sock < listen_sockets; sock++)
+                       if(sa->sa.sa_family == listen_socket[sock].sa.sa.sa_family)
+                               break;
+
+       if(sock >= listen_sockets)
+               sock = 0;
+
+       if(!n->status.udp_confirmed)
+               n->sock = sock;
+
 #if defined(SOL_IP) && defined(IP_TOS)
        if(priorityinheritance && origpriority != priority
           && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
@@ -574,7 +612,9 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        }
 #endif
 
-       if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+       socklen_t sl = SALEN(n->address.sa);
+
+       if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &sa->sa, sl) < 0 && !sockwouldblock(sockerrno)) {
                if(sockmsgsize(sockerrno)) {
                        if(n->maxmtu >= origlen)
                                n->maxmtu = origlen - 1;

diff --git a/src/node.h b/src/node.h
index d6d07d4..d0dccf3 100644 (file)
--- a/src/node.h
+++ b/src/node.h
@@ -35,7 +35,8 @@ typedef struct node_status_t {
        unsigned int reachable:1;               /* 1 if this node is reachable in the graph */
        unsigned int indirect:1;                /* 1 if this node is not directly reachable by us */
        unsigned int sptps:1;                   /* 1 if this node supports SPTPS */
-       unsigned int unused:25;
+       unsigned int udp_confirmed:1;           /* 1 if the address is one that we received UDP traffic on */
+       unsigned int unused:24;
 } node_status_t;
 
 typedef struct node_t {