+ unsigned int i = 0;
+ unsigned int j = rand() % n->edge_tree->count;
+ edge_t *candidate = NULL;
+
+ for splay_each(edge_t, e, n->edge_tree) {
+ if(i++ == j) {
+ candidate = e->reverse;
+ break;
+ }
+ }
+
+ if(candidate) {
+ *sa = &candidate->address;
+ *sock = rand() % listen_sockets;
+ }
+
+ adapt_socket(*sa, sock);
+}
+
+static void choose_local_address(const node_t *n, const sockaddr_t **sa, size_t *sock) {
+ *sa = NULL;
+
+ /* Pick one of the edges from this node at random, then use its local address. */
+
+ unsigned int i = 0;
+ unsigned int j = rand() % n->edge_tree->count;
+ edge_t *candidate = NULL;
+
+ for splay_each(edge_t, e, n->edge_tree) {
+ if(i++ == j) {
+ candidate = e;
+ break;
+ }
+ }
+
+ if(candidate && candidate->local_address.sa.sa_family) {
+ *sa = &candidate->local_address;
+ *sock = rand() % listen_sockets;
+ adapt_socket(*sa, sock);
+ }
+}
+
+static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
+ if(!n->status.reachable) {
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
+ return;
+ }
+
+ if(n->status.sptps) {
+ send_sptps_packet(n, origpkt);
+ return;
+ }
+
+#ifdef DISABLE_LEGACY
+ return;
+#else
+ vpn_packet_t pkt1, pkt2;
+ vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
+ vpn_packet_t *inpkt = origpkt;
+ int nextpkt = 0;
+ vpn_packet_t *outpkt;
+ int origlen = origpkt->len;
+ size_t outlen;
+ int origpriority = origpkt->priority;
+
+ pkt1.offset = DEFAULT_PACKET_OFFSET;
+ pkt2.offset = DEFAULT_PACKET_OFFSET;
+
+ /* Make sure we have a valid key */
+
+ if(!n->status.validkey) {
+ logger(DEBUG_TRAFFIC, LOG_INFO,
+ "No valid key known yet for %s (%s), forwarding via TCP",
+ n->name, n->hostname);
+ send_tcppacket(n->nexthop->connection, origpkt);
+ return;
+ }
+
+ if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (DATA(inpkt)[12] | DATA(inpkt)[13])) {
+ logger(DEBUG_TRAFFIC, LOG_INFO,
+ "Packet for %s (%s) larger than minimum MTU, forwarding via %s",
+ n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP");
+
+ if(n != n->nexthop) {
+ send_packet(n->nexthop, origpkt);
+ } else {
+ send_tcppacket(n->nexthop->connection, origpkt);
+ }
+
+ return;
+ }
+
+ /* Compress the packet */
+
+ if(n->outcompression != COMPRESS_NONE) {
+ outpkt = pkt[nextpkt++];
+
+ if(!(outpkt->len = compress_packet(DATA(outpkt), DATA(inpkt), inpkt->len, n->outcompression))) {
+ logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)",
+ n->name, n->hostname);
+ return;
+ }
+
+ inpkt = outpkt;
+ }
+
+ /* Add sequence number */
+
+ seqno_t seqno = htonl(++(n->sent_seqno));
+ memcpy(SEQNO(inpkt), &seqno, sizeof(seqno));
+ inpkt->len += sizeof(seqno);
+
+ /* Encrypt the packet */
+
+ if(cipher_active(n->outcipher)) {
+ outpkt = pkt[nextpkt++];
+ outlen = MAXSIZE;
+
+ if(!cipher_encrypt(n->outcipher, SEQNO(inpkt), inpkt->len, SEQNO(outpkt), &outlen, true)) {
+ logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
+ goto end;
+ }
+
+ outpkt->len = outlen;
+ inpkt = outpkt;
+ }
+
+ /* Add the message authentication code */
+
+ if(digest_active(n->outdigest)) {
+ if(!digest_create(n->outdigest, SEQNO(inpkt), inpkt->len, SEQNO(inpkt) + inpkt->len)) {
+ logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
+ goto end;
+ }
+
+ inpkt->len += digest_length(n->outdigest);
+ }
+
+ /* Send the packet */
+
+ const sockaddr_t *sa = NULL;
+ size_t sock;
+
+ if(n->status.send_locally) {
+ choose_local_address(n, &sa, &sock);
+ }
+
+ if(!sa) {
+ choose_udp_address(n, &sa, &sock);
+ }
+
+ if(priorityinheritance && origpriority != listen_socket[sock].priority) {
+ listen_socket[sock].priority = origpriority;
+
+ switch(sa->sa.sa_family) {
+#if defined(IP_TOS)
+
+ case AF_INET:
+ logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting IPv4 outgoing packet priority to %d", origpriority);
+
+ if(setsockopt(listen_socket[sock].udp.fd, IPPROTO_IP, IP_TOS, (void *)&origpriority, sizeof(origpriority))) { /* SO_PRIORITY doesn't seem to work */
+ logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "setsockopt", sockstrerror(sockerrno));
+ }
+
+ break;
+#endif
+#if defined(IPV6_TCLASS)
+
+ case AF_INET6:
+ logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting IPv6 outgoing packet priority to %d", origpriority);
+
+ if(setsockopt(listen_socket[sock].udp.fd, IPPROTO_IPV6, IPV6_TCLASS, (void *)&origpriority, sizeof(origpriority))) { /* SO_PRIORITY doesn't seem to work */
+ logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "setsockopt", sockstrerror(sockerrno));
+ }
+
+ break;
+#endif
+
+ default:
+ break;
+ }
+ }
+
+ if(sendto(listen_socket[sock].udp.fd, (void *)SEQNO(inpkt), inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
+ if(sockmsgsize(sockerrno)) {
+ if(n->maxmtu >= origlen) {
+ n->maxmtu = origlen - 1;
+ }
+
+ if(n->mtu >= origlen) {
+ n->mtu = origlen - 1;
+ }
+
+ try_fix_mtu(n);
+ } else {
+ logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
+ }
+ }