Add the LocalDiscoveryAddress option.
[oweals/tinc.git] / src / net_packet.c
index 371632fa3c57c18ff7c204754a41463555acff65..4bbb2d6f16e560bd5911addf946b8ca379d713fc 100644 (file)
@@ -1,7 +1,7 @@
 /*
     net_packet.c -- Handles in- and outgoing VPN packets
     Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2012 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2013 Guus Sliepen <guus@tinc-vpn.org>
                   2010      Timothy Redaelli <timothy@redaelli.eu>
                   2010      Brandon Black <blblack@gmail.com>
 
 
 #include "system.h"
 
-#include <openssl/rand.h>
-#include <openssl/err.h>
-#include <openssl/evp.h>
-#include <openssl/pem.h>
-#include <openssl/hmac.h>
-
 #ifdef HAVE_ZLIB
 #include <zlib.h>
 #endif
@@ -36,7 +30,6 @@
 #include LZO1X_H
 #endif
 
-#include "splay_tree.h"
 #include "cipher.h"
 #include "conf.h"
 #include "connection.h"
@@ -63,6 +56,7 @@ static void send_udppacket(node_t *, vpn_packet_t *);
 
 unsigned replaywin = 16;
 bool localdiscovery = false;
+sockaddr_t localdiscovery_address;
 
 #define MAX_SEQNO 1073741824
 
@@ -71,19 +65,21 @@ bool localdiscovery = false;
    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.
+   Probes are sent in batches of at least three, with random sizes between the
+   lower and upper boundaries for the MTU thus far discovered.
+
+   After the initial discovery, a fourth packet is added to each batch with a
+   size larger than the currently known PMTU, to test if the PMTU has increased.
 
-   In case local discovery is enabled, a fourth packet is added to each batch,
+   In case local discovery is enabled, another 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) {
+static void send_mtu_probe_handler(void *data) {
        node_t *n = data;
-       vpn_packet_t packet;
-       int len, i;
        int timeout = 1;
-       
+
        n->mtuprobes++;
 
        if(!n->status.reachable || !n->status.validkey) {
@@ -100,6 +96,7 @@ 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;
@@ -127,19 +124,27 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
                timeout = pingtimeout;
        }
 
-       for(i = 0; i < 3 + localdiscovery; i++) {
-               if(n->maxmtu <= n->minmtu)
+       for(int i = 0; i < 4 + localdiscovery; i++) {
+               int len;
+
+               if(i == 0) {
+                       if(n->mtuprobes < 30 || n->maxmtu + 8 >= MTU)
+                               continue;
+                       len = n->maxmtu + 8;
+               } else if(n->maxmtu <= n->minmtu) {
                        len = n->maxmtu;
-               else
+               } else {
                        len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+               }
 
                if(len < 64)
                        len = 64;
-               
+
+               vpn_packet_t packet;
                memset(packet.data, 0, 14);
                randomize(packet.data + 14, len - 14);
                packet.len = len;
-               if(i >= 3 && n->mtuprobes <= 10)
+               if(i >= 4 && n->mtuprobes <= 10)
                        packet.priority = -1;
                else
                        packet.priority = 0;
@@ -149,34 +154,93 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
                send_udppacket(n, &packet);
        }
 
+       n->probe_counter = 0;
+       gettimeofday(&n->probe_time, NULL);
+
+       /* Calculate the packet loss of incoming traffic by comparing the rate of
+          packets received to the rate with which the sequence number has increased.
+        */
+
+       if(n->received > n->prev_received)
+               n->packetloss = 1.0 - (n->received - n->prev_received) / (float)(n->received_seqno - n->prev_received_seqno);
+       else
+               n->packetloss = n->received_seqno <= n->prev_received_seqno;
+
+       n->prev_received_seqno = n->received_seqno;
+       n->prev_received = n->received;
+
 end:
-       event_add(&n->mtuevent, &(struct timeval){timeout, 0});
+       timeout_set(&n->mtutimeout, &(struct timeval){timeout, rand() % 100000});
 }
 
 void send_mtu_probe(node_t *n) {
-       if(!timeout_initialized(&n->mtuevent))
-               timeout_set(&n->mtuevent, send_mtu_probe_handler, n);
-       send_mtu_probe_handler(0, 0, n);
+       timeout_add(&n->mtutimeout, send_mtu_probe_handler, n, &(struct timeval){1, 0});
+       send_mtu_probe_handler(n);
 }
 
 static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
        logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
 
        if(!packet->data[0]) {
+               /* It's a probe request, send back a reply */
+
                packet->data[0] = 1;
+
+               /* Temporarily set udp_confirmed, so that the reply is sent
+                  back exactly the way it came in. */
+
+               bool udp_confirmed = n->status.udp_confirmed;
+               n->status.udp_confirmed = true;
                send_udppacket(n, packet);
+               n->status.udp_confirmed = udp_confirmed;
        } else {
+               /* It's a valid reply: now we know bidirectional communication
+                  is possible using the address and socket that the reply
+                  packet used. */
+
+               n->status.udp_confirmed = true;
+
+               /* If we haven't established the PMTU yet, restart the discovery process. */
+
                if(n->mtuprobes > 30) {
+                       if (len == n->maxmtu + 8) {
+                               logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
+                               n->maxmtu = MTU;
+                               n->mtuprobes = 10;
+                               return;
+                       }
+
                        if(n->minmtu)
                                n->mtuprobes = 30;
                        else
                                n->mtuprobes = 1;
                }
 
+               /* If applicable, raise the minimum supported MTU */
+
                if(len > n->maxmtu)
                        len = n->maxmtu;
                if(n->minmtu < len)
                        n->minmtu = len;
+
+               /* Calculate RTT and bandwidth.
+                  The RTT is the time between the MTU probe burst was sent and the first
+                  reply is received. The bandwidth is measured using the time between the
+                  arrival of the first and third probe reply.
+                */
+
+               struct timeval now, diff;
+               gettimeofday(&now, NULL);
+               timersub(&now, &n->probe_time, &diff);
+               n->probe_counter++;
+
+               if(n->probe_counter == 1) {
+                       n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
+                       n->probe_time = now;
+               } else if(n->probe_counter == 3) {
+                       n->bandwidth = 2.0 * len / (diff.tv_sec + diff.tv_usec * 1e-6);
+                       logger(DEBUG_TRAFFIC, LOG_DEBUG, "%s (%s) RTT %.2f ms, burst bandwidth %.3f Mbit/s, rx packet loss %.2f %%", n->name, n->hostname, n->rtt * 1e3, n->bandwidth * 8e-6, n->packetloss * 1e2);
+               }
        }
 }
 
@@ -209,7 +273,7 @@ static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t l
                return -1;
 #endif
        }
-       
+
        return -1;
 }
 
@@ -255,10 +319,10 @@ static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
        if(n->status.sptps)
                return sptps_verify_datagram(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
 
-       if(!digest_active(&n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest))
+       if(!digest_active(n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest))
                return false;
 
-       return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
+       return digest_verify(n->indigest, &inpkt->seqno, inpkt->len - digest_length(n->indigest), (const char *)&inpkt->seqno + inpkt->len - digest_length(n->indigest));
 }
 
 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
@@ -269,19 +333,27 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
        size_t outlen;
 
        if(n->status.sptps) {
+               if(!n->sptps.state) {
+                       if(!n->status.waitingforkey) {
+                               logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but we haven't exchanged keys yet", n->name, n->hostname);
+                               send_req_key(n);
+                       } else {
+                               logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
+                       }
+                       return;
+               }
                sptps_receive_data(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
                return;
        }
 
-       if(!cipher_active(&n->incipher)) {
-               logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
-                                       n->name, n->hostname);
+       if(!cipher_active(n->incipher)) {
+               logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
                return;
        }
 
        /* Check packet length */
 
-       if(inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest)) {
+       if(inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest)) {
                logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got too short packet from %s (%s)",
                                        n->name, n->hostname);
                return;
@@ -289,24 +361,24 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
        /* Check the message authentication code */
 
-       if(digest_active(&n->indigest)) {
-               inpkt->len -= n->indigest.maclength;
-               if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
+       if(digest_active(n->indigest)) {
+               inpkt->len -= digest_length(n->indigest);
+               if(!digest_verify(n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
                        logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
                        return;
                }
        }
        /* Decrypt the packet */
 
-       if(cipher_active(&n->incipher)) {
+       if(cipher_active(n->incipher)) {
                outpkt = pkt[nextpkt++];
                outlen = MAXSIZE;
 
-               if(!cipher_decrypt(&n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+               if(!cipher_decrypt(n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
                        logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
                        return;
                }
-               
+
                outpkt->len = outlen;
                inpkt = outpkt;
        }
@@ -325,12 +397,12 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
                                        return;
                                }
                                logger(DEBUG_ALWAYS, LOG_WARNING, "Lost %d packets from %s (%s)",
-                                               inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
+                                               inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
                                memset(n->late, 0, replaywin);
                        } else if (inpkt->seqno <= n->received_seqno) {
                                if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
                                        logger(DEBUG_ALWAYS, LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
-                                               n->name, n->hostname, inpkt->seqno, n->received_seqno);
+                                               n->name, n->hostname, inpkt->seqno, n->received_seqno);
                                        return;
                                }
                        } else {
@@ -345,7 +417,9 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
        if(inpkt->seqno > n->received_seqno)
                n->received_seqno = inpkt->seqno;
-                       
+
+       n->received++;
+
        if(n->received_seqno > MAX_SEQNO)
                regenerate_key();
 
@@ -358,7 +432,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
                if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
                        logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
-                                                n->name, n->hostname);
+                                                n->name, n->hostname);
                        return;
                }
 
@@ -378,6 +452,9 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 void receive_tcppacket(connection_t *c, const char *buffer, int len) {
        vpn_packet_t outpkt;
 
+       if(len > sizeof outpkt.data)
+               return;
+
        outpkt.len = len;
        if(c->options & OPTION_TCPONLY)
                outpkt.priority = 0;
@@ -393,11 +470,13 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
                logger(DEBUG_TRAFFIC, LOG_INFO, "No valid key known yet for %s (%s)", n->name, n->hostname);
                if(!n->status.waitingforkey)
                        send_req_key(n);
-               else if(n->last_req_key + 10 < time(NULL)) {
+               else if(n->last_req_key + 10 < now.tv_sec) {
+                       logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
                        sptps_stop(&n->sptps);
                        n->status.waitingforkey = false;
                        send_req_key(n);
                }
+               return;
        }
 
        uint8_t type = 0;
@@ -433,6 +512,94 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
        return;
 }
 
+static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+       /* Latest guess */
+       *sa = &n->address;
+       *sock = n->sock;
+
+       /* If the UDP address is confirmed, use it. */
+       if(n->status.udp_confirmed)
+               return;
+
+       /* Send every third packet to n->address; that could be set
+          to the node's reflexive UDP address discovered during key
+          exchange. */
+
+       static int x = 0;
+       if(++x >= 3) {
+               x = 0;
+               return;
+       }
+
+       /* Otherwise, address are found in edges to this node.
+          So we pick a random edge and a random socket. */
+
+       int i = 0;
+       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;
+       }
+
+       /* Make sure we have a suitable socket for the chosen address */
+       if(listen_socket[*sock].sa.sa.sa_family != (*sa)->sa.sa_family) {
+               for(int i = 0; i < listen_sockets; i++) {
+                       if(listen_socket[i].sa.sa.sa_family == (*sa)->sa.sa_family) {
+                               *sock = i;
+                               break;
+                       }
+               }
+       }
+}
+
+static void choose_broadcast_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+       static sockaddr_t broadcast_ipv4 = {
+               .in = {
+                       .sin_family = AF_INET,
+                       .sin_addr.s_addr = -1,
+               }
+       };
+
+       static sockaddr_t broadcast_ipv6 = {
+               .in6 = {
+                       .sin6_family = AF_INET6,
+                       .sin6_addr.s6_addr[0x0] = 0xff,
+                       .sin6_addr.s6_addr[0x1] = 0x02,
+                       .sin6_addr.s6_addr[0xf] = 0x01,
+               }
+       };
+
+       *sock = rand() % listen_sockets;
+
+       if(listen_socket[*sock].sa.sa.sa_family == AF_INET6) {
+               if(localdiscovery_address.sa.sa_family == AF_INET6) {
+                       localdiscovery_address.in6.sin6_port = n->prevedge->address.in.sin_port;
+                       *sa = &localdiscovery_address;
+               } else {
+                       broadcast_ipv6.in6.sin6_port = n->prevedge->address.in.sin_port;
+                       broadcast_ipv6.in6.sin6_scope_id = listen_socket[*sock].sa.in6.sin6_scope_id;
+                       *sa = &broadcast_ipv6;
+               }
+       } else {
+               if(localdiscovery_address.sa.sa_family == AF_INET) {
+                       localdiscovery_address.in.sin_port = n->prevedge->address.in.sin_port;
+                       *sa = &localdiscovery_address;
+               } else {
+                       broadcast_ipv4.in.sin_port = n->prevedge->address.in.sin_port;
+                       *sa = &broadcast_ipv4;
+               }
+       }
+}
+
 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        vpn_packet_t pkt1, pkt2;
        vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
@@ -457,15 +624,13 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        /* Make sure we have a valid key */
 
        if(!n->status.validkey) {
-               time_t now = time(NULL);
-
                logger(DEBUG_TRAFFIC, LOG_INFO,
                                   "No valid key known yet for %s (%s), forwarding via TCP",
                                   n->name, n->hostname);
 
-               if(n->last_req_key + 10 <= now) {
+               if(n->last_req_key + 10 <= now.tv_sec) {
                        send_req_key(n);
-                       n->last_req_key = now;
+                       n->last_req_key = now.tv_sec;
                }
 
                send_tcppacket(n->nexthop->connection, origpkt);
@@ -507,11 +672,11 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
        /* Encrypt the packet */
 
-       if(cipher_active(&n->outcipher)) {
+       if(cipher_active(n->outcipher)) {
                outpkt = pkt[nextpkt++];
                outlen = MAXSIZE;
 
-               if(!cipher_encrypt(&n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+               if(!cipher_encrypt(n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
                        logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
                        goto end;
                }
@@ -522,58 +687,38 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
        /* Add the message authentication code */
 
-       if(digest_active(&n->outdigest)) {
-               digest_create(&n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len);
-               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;
-                       }
+       if(digest_active(n->outdigest)) {
+               if(!digest_create(n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + 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 */
 
-       struct sockaddr *sa;
-       socklen_t sl;
+       const 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;
-               sock = 0;
-       } else {
-               if(origpriority == -1)
-                       origpriority = 0;
-
-               sa = &(n->address.sa);
-               sl = SALEN(n->address.sa);
-               sock = n->sock;
-       }
+       if(origpriority == -1 && n->prevedge)
+               choose_broadcast_address(n, &sa, &sock);
+       else
+               choose_udp_address(n, &sa, &sock);
 
 #if defined(SOL_IP) && defined(IP_TOS)
        if(priorityinheritance && origpriority != priority
           && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
                priority = origpriority;
                logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
-               if(setsockopt(listen_socket[n->sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
+               if(setsockopt(listen_socket[n->sock].udp.fd, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
                        logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno));
        }
 #endif
 
-       if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+       if(sendto(listen_socket[sock].udp.fd, (char *) &inpkt->seqno, inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
                if(sockmsgsize(sockerrno)) {
                        if(n->maxmtu >= origlen)
                                n->maxmtu = origlen - 1;
@@ -590,26 +735,27 @@ end:
 bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
        node_t *to = handle;
 
-       if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY)) {
+       /* Send it via TCP if it is a handshake packet, TCPOnly is in use, or this packet is larger than the MTU. */
+
+       if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && len > to->minmtu)) {
                char buf[len * 4 / 3 + 5];
                b64encode(data, buf, len);
+               /* If no valid key is known yet, send the packets using ANS_KEY requests,
+                  to ensure we get to learn the reflexive UDP address. */
                if(!to->status.validkey)
                        return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, myself->incompression);
                else
                        return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_SPTPS, buf);
        }
 
-       /* Send the packet */
+       /* Otherwise, send the packet via UDP */
 
-       struct sockaddr *sa;
-       socklen_t sl;
+       const sockaddr_t *sa;
        int sock;
 
-       sa = &(to->address.sa);
-       sl = SALEN(to->address.sa);
-       sock = to->sock;
+       choose_udp_address(to, &sa, &sock);
 
-       if(sendto(listen_socket[sock].udp, data, len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+       if(sendto(listen_socket[sock].udp.fd, data, len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
                if(sockmsgsize(sockerrno)) {
                        if(to->maxmtu >= len)
                                to->maxmtu = len - 1;
@@ -628,9 +774,11 @@ bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t
        node_t *from = handle;
 
        if(type == SPTPS_HANDSHAKE) {
-               from->status.validkey = true;
-               from->status.waitingforkey = false;
-               logger(DEBUG_META, LOG_INFO, "SPTPS key exchange with %s (%s) succesful", from->name, from->hostname);
+               if(!from->status.validkey) {
+                       from->status.validkey = true;
+                       from->status.waitingforkey = false;
+                       logger(DEBUG_META, LOG_INFO, "SPTPS key exchange with %s (%s) succesful", from->name, from->hostname);
+               }
                return true;
        }
 
@@ -663,11 +811,11 @@ bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t
 
        int offset = (type & PKT_MAC) ? 0 : 14;
        if(type & PKT_COMPRESSED) {
-               len = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
-               if(len < 0) {
+               length_t ulen = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
+               if(ulen < 0) {
                        return false;
                } else {
-                       inpkt.len = len + offset;
+                       inpkt.len = ulen + offset;
                }
                if(inpkt.len > MAXSIZE)
                        abort();
@@ -747,16 +895,12 @@ void send_packet(node_t *n, vpn_packet_t *packet) {
 /* Broadcast a packet using the minimum spanning tree */
 
 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
-       splay_node_t *node;
-       connection_t *c;
-       node_t *n;
-
        // Always give ourself a copy of the packet.
        if(from != myself)
                send_packet(myself, packet);
 
        // In TunnelServer mode, do not forward broadcast packets.
-        // The MST might not be valid and create loops.
+       // The MST might not be valid and create loops.
        if(tunnelserver || broadcast_mode == BMODE_NONE)
                return;
 
@@ -768,27 +912,21 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
                // This guarantees all nodes receive the broadcast packet, and
                // usually distributes the sending of broadcast packets over all nodes.
                case BMODE_MST:
-                       for(node = connection_tree->head; node; node = node->next) {
-                               c = node->data;
-
+                       for list_each(connection_t, c, connection_list)
                                if(c->status.active && c->status.mst && c != from->nexthop->connection)
                                        send_packet(c->node, packet);
-                       }
                        break;
 
                // In direct mode, we send copies to each node we know of.
-               // However, this only reaches nodes that can be reached in a single hop.
+               // However, this only reaches nodes that can be reached in a single hop.
                // We don't have enough information to forward broadcast packets in this case.
                case BMODE_DIRECT:
                        if(from != myself)
                                break;
 
-                       for(node = node_tree->head; node; node = node->next) {
-                               n = node->data;
-
+                       for splay_each(node_t, n, node_tree)
                                if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n))
                                        send_packet(n, packet);
-                       }
                        break;
 
                default:
@@ -797,21 +935,16 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
 }
 
 static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
-       splay_node_t *node;
-       edge_t *e;
        node_t *n = NULL;
        bool hard = false;
        static time_t last_hard_try = 0;
-       time_t now = time(NULL);
-
-       for(node = edge_weight_tree->head; node; node = node->next) {
-               e = node->data;
 
+       for splay_each(edge_t, e, edge_weight_tree) {
                if(!e->to->status.reachable || e->to == myself)
                        continue;
 
                if(sockaddrcmp_noport(from, &e->address)) {
-                       if(last_hard_try == now)
+                       if(last_hard_try == now.tv_sec)
                                continue;
                        hard = true;
                }
@@ -824,13 +957,14 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
        }
 
        if(hard)
-               last_hard_try = now;
+               last_hard_try = now.tv_sec;
 
-       last_hard_try = now;
+       last_hard_try = now.tv_sec;
        return n;
 }
 
-void handle_incoming_vpn_data(int sock, short events, void *data) {
+void handle_incoming_vpn_data(void *data, int flags) {
+       listen_socket_t *ls = data;
        vpn_packet_t pkt;
        char *hostname;
        sockaddr_t from = {{0}};
@@ -838,7 +972,7 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
        node_t *n;
        int len;
 
-       len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+       len = recvfrom(ls->udp.fd, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
        if(len <= 0 || len > MAXSIZE) {
                if(!sockwouldblock(sockerrno))
@@ -848,7 +982,7 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 
        pkt.len = len;
 
-       sockaddrunmap(&from);           /* Some braindead IPv6 implementations do stupid things. */
+       sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
 
        n = lookup_node_udp(&from);
 
@@ -866,12 +1000,12 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
                        return;
        }
 
-       n->sock = (intptr_t)data;
+       n->sock = ls - listen_socket;
 
        receive_udppacket(n, &pkt);
 }
 
-void handle_device_data(int sock, short events, void *data) {
+void handle_device_data(void *data, int flags) {
        vpn_packet_t packet;
 
        packet.priority = 0;