Replace the connection_tree with a connection_list.
[tinc] / src / net_packet.c
index 7d640cb..c9a6663 100644 (file)
@@ -1,7 +1,9 @@
 /*
     net_packet.c -- Handles in- and outgoing VPN packets
     Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2009 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2012 Guus Sliepen <guus@tinc-vpn.org>
+                  2010      Timothy Redaelli <timothy@redaelli.eu>
+                  2010      Brandon Black <blblack@gmail.com>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
-    $Id$
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
 #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
+
+#ifdef HAVE_LZO
 #include LZO1X_H
+#endif
 
-#include "splay_tree.h"
 #include "cipher.h"
 #include "conf.h"
 #include "connection.h"
@@ -34,7 +44,6 @@
 #include "device.h"
 #include "ethernet.h"
 #include "graph.h"
-#include "list.h"
 #include "logger.h"
 #include "net.h"
 #include "netutl.h"
 #include "utils.h"
 #include "xalloc.h"
 
-#ifdef WSAEMSGSIZE
-#define EMSGSIZE WSAEMSGSIZE
-#endif
-
 int keylifetime = 0;
+#ifdef HAVE_LZO
 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
+#endif
 
 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
+
+   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;
        vpn_packet_t packet;
        int len, i;
+       int timeout = 1;
        
-       cp();
-
        n->mtuprobes++;
 
-       if(n->mtuprobes >= 10 && !n->minmtu) {
-               ifdebug(TRAFFIC) logger(LOG_INFO, _("No response to MTU probes from %s (%s)"), n->name, n->hostname);
+       if(!n->status.reachable || !n->status.validkey) {
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
+               n->mtuprobes = 0;
                return;
        }
 
-       for(i = 0; i < 3; i++) {
-               if(n->mtuprobes >= 30 || n->minmtu >= n->maxmtu) {
-                       n->mtu = n->minmtu;
-                       ifdebug(TRAFFIC) logger(LOG_INFO, _("Fixing MTU of %s (%s) to %d after %d probes"), n->name, n->hostname, n->mtu, n->mtuprobes);
-                       return;
+       if(n->mtuprobes > 32) {
+               if(!n->minmtu) {
+                       n->mtuprobes = 31;
+                       timeout = pinginterval;
+                       goto end;
                }
 
-               len = n->minmtu + 1 + random() % (n->maxmtu - n->minmtu);
+               logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
+               n->mtuprobes = 1;
+               n->minmtu = 0;
+               n->maxmtu = MTU;
+       }
+
+       if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
+               logger(DEBUG_TRAFFIC, LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
+               n->mtuprobes = 31;
+       }
+
+       if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
+               if(n->minmtu > n->maxmtu)
+                       n->minmtu = n->maxmtu;
+               else
+                       n->maxmtu = n->minmtu;
+               n->mtu = n->minmtu;
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
+               n->mtuprobes = 31;
+       }
+
+       if(n->mtuprobes == 31) {
+               timeout = pinginterval;
+               goto end;
+       } else if(n->mtuprobes == 32) {
+               timeout = pingtimeout;
+       }
+
+       for(i = 0; i < 3 + localdiscovery; i++) {
+               if(n->maxmtu <= n->minmtu)
+                       len = n->maxmtu;
+               else
+                       len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+
                if(len < 64)
                        len = 64;
                
                memset(packet.data, 0, 14);
                randomize(packet.data + 14, len - 14);
                packet.len = len;
-               packet.priority = 0;
+               if(i >= 3 && n->mtuprobes <= 10)
+                       packet.priority = -1;
+               else
+                       packet.priority = 0;
 
-               ifdebug(TRAFFIC) logger(LOG_INFO, _("Sending MTU probe length %d to %s (%s)"), len, n->name, n->hostname);
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
 
                send_udppacket(n, &packet);
        }
 
-       event_add(&n->mtuevent, &(struct timeval){1, 0});
+end:
+       event_add(&n->mtuevent, &(struct timeval){timeout, 0});
 }
 
 void send_mtu_probe(node_t *n) {
@@ -99,100 +158,151 @@ void send_mtu_probe(node_t *n) {
        send_mtu_probe_handler(0, 0, n);
 }
 
-void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
-       ifdebug(TRAFFIC) logger(LOG_INFO, _("Got MTU probe length %d from %s (%s)"), packet->len, n->name, n->hostname);
+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]) {
                packet->data[0] = 1;
-               send_packet(n, packet);
+               send_udppacket(n, packet);
        } else {
-               if(n->minmtu < packet->len)
-                       n->minmtu = packet->len;
+               if(n->mtuprobes > 30) {
+                       if(n->minmtu)
+                               n->mtuprobes = 30;
+                       else
+                               n->mtuprobes = 1;
+               }
+
+               if(len > n->maxmtu)
+                       len = n->maxmtu;
+               if(n->minmtu < len)
+                       n->minmtu = len;
        }
 }
 
 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
-       if(level == 10) {
+       if(level == 0) {
+               memcpy(dest, source, len);
+               return len;
+       } else if(level == 10) {
+#ifdef HAVE_LZO
                lzo_uint lzolen = MAXSIZE;
                lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
                return lzolen;
+#else
+               return -1;
+#endif
        } else if(level < 10) {
+#ifdef HAVE_ZLIB
                unsigned long destlen = MAXSIZE;
                if(compress2(dest, &destlen, source, len, level) == Z_OK)
                        return destlen;
                else
+#endif
                        return -1;
        } else {
+#ifdef HAVE_LZO
                lzo_uint lzolen = MAXSIZE;
                lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
                return lzolen;
+#else
+               return -1;
+#endif
        }
        
        return -1;
 }
 
 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
-       if(level > 9) {
+       if(level == 0) {
+               memcpy(dest, source, len);
+               return len;
+       } else if(level > 9) {
+#ifdef HAVE_LZO
                lzo_uint lzolen = MAXSIZE;
                if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
                        return lzolen;
                else
+#endif
                        return -1;
-       } else {
+       }
+#ifdef HAVE_ZLIB
+       else {
                unsigned long destlen = MAXSIZE;
                if(uncompress(dest, &destlen, source, len) == Z_OK)
                        return destlen;
                else
                        return -1;
        }
-       
+#endif
+
        return -1;
 }
 
 /* VPN packet I/O */
 
 static void receive_packet(node_t *n, vpn_packet_t *packet) {
-       cp();
-
-       ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
+       logger(DEBUG_TRAFFIC, LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
                           packet->len, n->name, n->hostname);
 
+       n->in_packets++;
+       n->in_bytes += packet->len;
+
        route(n, packet);
 }
 
+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))
+               return false;
+
+       return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
+}
+
 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
        vpn_packet_t pkt1, pkt2;
        vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
        int nextpkt = 0;
        vpn_packet_t *outpkt = pkt[0];
        size_t outlen;
-       int i;
 
-       cp();
+       if(n->status.sptps) {
+               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);
+               return;
+       }
 
        /* Check packet length */
 
-       if(inpkt->len < sizeof inpkt->seqno + digest_length(&myself->digest)) {
-               ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
+       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;
        }
 
        /* Check the message authentication code */
 
-       if(digest_active(&myself->digest) && !digest_verify(&myself->digest, &inpkt->seqno, inpkt->len, &inpkt->seqno + inpkt->len)) {
-               ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"), n->name, n->hostname);
-               return;
+       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)) {
+                       logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
+                       return;
+               }
        }
-
        /* Decrypt the packet */
 
-       if(cipher_active(&myself->cipher)) {
+       if(cipher_active(&n->incipher)) {
                outpkt = pkt[nextpkt++];
                outlen = MAXSIZE;
 
-               if(!cipher_decrypt(&myself->cipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
-                       ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s)"), n->name, n->hostname);
+               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;
                }
                
@@ -205,25 +315,32 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
        inpkt->len -= sizeof inpkt->seqno;
        inpkt->seqno = ntohl(inpkt->seqno);
 
-       if(inpkt->seqno != n->received_seqno + 1) {
-               if(inpkt->seqno >= n->received_seqno + sizeof n->late * 8) {
-                       logger(LOG_WARNING, _("Lost %d packets from %s (%s)"),
-                                          inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
-                       
-                       memset(n->late, 0, sizeof n->late);
-               } else if (inpkt->seqno <= n->received_seqno) {
-                       if((n->received_seqno >= sizeof n->late * 8 && inpkt->seqno <= n->received_seqno - sizeof n->late * 8) || !(n->late[(inpkt->seqno / 8) % sizeof n->late] & (1 << inpkt->seqno % 8))) {
-                               logger(LOG_WARNING, _("Got late or replayed packet from %s (%s), seqno %d, last received %d"),
-                                          n->name, n->hostname, inpkt->seqno, n->received_seqno);
-                               return;
+       if(replaywin) {
+               if(inpkt->seqno != n->received_seqno + 1) {
+                       if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
+                               if(n->farfuture++ < replaywin >> 2) {
+                                       logger(DEBUG_ALWAYS, LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
+                                               n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture);
+                                       return;
+                               }
+                               logger(DEBUG_ALWAYS, LOG_WARNING, "Lost %d packets from %s (%s)",
+                                               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);
+                                       return;
+                               }
+                       } else {
+                               for(int i = n->received_seqno + 1; i < inpkt->seqno; i++)
+                                       n->late[(i / 8) % replaywin] |= 1 << i % 8;
                        }
-               } else {
-                       for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
-                               n->late[(i / 8) % sizeof n->late] |= 1 << i % 8;
                }
+
+               n->farfuture = 0;
+               n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
        }
-       
-       n->late[(inpkt->seqno / 8) % sizeof n->late] &= ~(1 << inpkt->seqno % 8);
 
        if(inpkt->seqno > n->received_seqno)
                n->received_seqno = inpkt->seqno;
@@ -233,31 +350,33 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
        /* Decompress the packet */
 
-       if(myself->compression) {
+       length_t origlen = inpkt->len;
+
+       if(n->incompression) {
                outpkt = pkt[nextpkt++];
 
-               if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
-                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
+               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);
                        return;
                }
 
                inpkt = outpkt;
+
+               origlen -= MTU/64 + 20;
        }
 
        inpkt->priority = 0;
 
        if(!inpkt->data[12] && !inpkt->data[13])
-               mtu_probe_h(n, inpkt);
+               mtu_probe_h(n, inpkt, origlen);
        else
                receive_packet(n, inpkt);
 }
 
-void receive_tcppacket(connection_t *c, char *buffer, int len) {
+void receive_tcppacket(connection_t *c, const char *buffer, int len) {
        vpn_packet_t outpkt;
 
-       cp();
-
        outpkt.len = len;
        if(c->options & OPTION_TCPONLY)
                outpkt.priority = 0;
@@ -268,55 +387,112 @@ void receive_tcppacket(connection_t *c, char *buffer, int len) {
        receive_packet(c->node, &outpkt);
 }
 
+static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
+       if(!n->status.validkey) {
+               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)) {
+                       sptps_stop(&n->sptps);
+                       n->status.waitingforkey = false;
+                       send_req_key(n);
+               }
+               return;
+       }
+
+       uint8_t type = 0;
+       int offset = 0;
+
+       if(!(origpkt->data[12] | origpkt->data[13])) {
+               sptps_send_record(&n->sptps, PKT_PROBE, (char *)origpkt->data, origpkt->len);
+               return;
+       }
+
+       if(routing_mode == RMODE_ROUTER)
+               offset = 14;
+       else
+               type = PKT_MAC;
+
+       if(origpkt->len < offset)
+               return;
+
+       vpn_packet_t outpkt;
+
+       if(n->outcompression) {
+               int len = compress_packet(outpkt.data + offset, origpkt->data + offset, origpkt->len - offset, n->outcompression);
+               if(len < 0) {
+                       logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)", n->name, n->hostname);
+               } else if(len < origpkt->len - offset) {
+                       outpkt.len = len + offset;
+                       origpkt = &outpkt;
+                       type |= PKT_COMPRESSED;
+               }
+       }
+
+       sptps_send_record(&n->sptps, type, (char *)origpkt->data + offset, origpkt->len - offset);
+       return;
+}
+
 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        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;
+       int origlen = origpkt->len;
        size_t outlen;
+#if defined(SOL_IP) && defined(IP_TOS)
        static int priority = 0;
-       int origpriority;
-       int sock;
+#endif
+       int origpriority = origpkt->priority;
 
-       cp();
+       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)
+               return send_sptps_packet(n, origpkt);
 
        /* Make sure we have a valid key */
 
        if(!n->status.validkey) {
-               ifdebug(TRAFFIC) logger(LOG_INFO,
-                                  _("No valid key known yet for %s (%s), forwarding via TCP"),
-                                  n->name, n->hostname);
+               time_t now = time(NULL);
 
-               if(!n->status.waitingforkey)
-                       send_req_key(n->nexthop->connection, myself, n);
+               logger(DEBUG_TRAFFIC, LOG_INFO,
+                                  "No valid key known yet for %s (%s), forwarding via TCP",
+                                  n->name, n->hostname);
 
-               n->status.waitingforkey = true;
+               if(n->last_req_key + 10 <= now) {
+                       send_req_key(n);
+                       n->last_req_key = now;
+               }
 
                send_tcppacket(n->nexthop->connection, origpkt);
 
                return;
        }
 
-       if(!n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
-               ifdebug(TRAFFIC) logger(LOG_INFO,
-                               _("No minimum MTU established yet for %s (%s), forwarding via TCP"),
-                               n->name, n->hostname);
+       if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[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");
 
-               send_tcppacket(n->nexthop->connection, origpkt);
-       }
+               if(n != n->nexthop)
+                       send_packet(n->nexthop, origpkt);
+               else
+                       send_tcppacket(n->nexthop->connection, origpkt);
 
-       origlen = inpkt->len;
-       origpriority = inpkt->priority;
+               return;
+       }
 
        /* Compress the packet */
 
-       if(n->compression) {
+       if(n->outcompression) {
                outpkt = pkt[nextpkt++];
 
-               if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
-                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
+               if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
+                       logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)",
                                   n->name, n->hostname);
                        return;
                }
@@ -331,12 +507,12 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
        /* Encrypt the packet */
 
-       if(cipher_active(&n->cipher)) {
+       if(cipher_active(&n->outcipher)) {
                outpkt = pkt[nextpkt++];
                outlen = MAXSIZE;
 
-               if(!cipher_encrypt(&n->cipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
-                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s)"), n->name, n->hostname);
+               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;
                }
 
@@ -346,74 +522,221 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
        /* Add the message authentication code */
 
-       if(digest_active(&n->digest)) {
-               digest_create(&n->digest, &inpkt->seqno, inpkt->len, &inpkt->seqno + inpkt->len);
-               inpkt->len += digest_length(&n->digest);
+       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 */
 
-       for(sock = 0; sock < listen_sockets; sock++)
-               if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
-                       break;
-
-       if(sock >= listen_sockets)
-               sock = 0;                               /* If none is available, just use the first and hope for the best. */
+       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;
+       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[sock].sa.sa.sa_family == AF_INET) {
+          && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
                priority = origpriority;
-               ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Setting outgoing packet priority to %d"), priority);
-               if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof priority))     /* SO_PRIORITY doesn't seem to work */
-                       logger(LOG_ERR, _("System call `%s' failed: %s"), "setsockopt", strerror(errno));
+               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 */
+                       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, &(n->address.sa), SALEN(n->address.sa))) < 0) {
-               if(errno == EMSGSIZE) {
+       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;
                        if(n->mtu >= origlen)
                                n->mtu = origlen - 1;
                } else
-                       logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
+                       logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
        }
 
 end:
        origpkt->len = origlen;
 }
 
+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)
+                       || (type != PKT_PROBE && len > to->minmtu)) {
+               char buf[len * 4 / 3 + 5];
+               b64encode(data, buf, len);
+               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, type >= SPTPS_HANDSHAKE ? REQ_SPTPS : REQ_PACKET, buf);
+       }
+
+       /* Send the packet */
+
+       struct sockaddr *sa;
+       socklen_t sl;
+       int sock;
+
+       sa = &(to->address.sa);
+       sl = SALEN(to->address.sa);
+       sock = to->sock;
+
+       if(sendto(listen_socket[sock].udp, data, len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+               if(sockmsgsize(sockerrno)) {
+                       if(to->maxmtu >= len)
+                               to->maxmtu = len - 1;
+                       if(to->mtu >= len)
+                               to->mtu = len - 1;
+               } else {
+                       logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", to->name, to->hostname, sockstrerror(sockerrno));
+                       return false;
+               }
+       }
+
+       return true;
+}
+
+bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t len) {
+       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);
+               return true;
+       }
+
+       if(len > MTU) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Packet from %s (%s) larger than maximum supported size (%d > %d)", from->name, from->hostname, len, MTU);
+               return false;
+       }
+
+       vpn_packet_t inpkt;
+
+       if(type == PKT_PROBE) {
+               inpkt.len = len;
+               memcpy(inpkt.data, data, len);
+               mtu_probe_h(from, &inpkt, len);
+               return true;
+       }
+
+       if(type & ~(PKT_COMPRESSED | PKT_MAC)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Unexpected SPTPS record type %d len %d from %s (%s)", type, len, from->name, from->hostname);
+               return false;
+       }
+
+       /* Check if we have the headers we need */
+       if(routing_mode != RMODE_ROUTER && !(type & PKT_MAC)) {
+               logger(DEBUG_TRAFFIC, LOG_ERR, "Received packet from %s (%s) without MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
+               return false;
+       } else if(routing_mode == RMODE_ROUTER && (type & PKT_MAC)) {
+               logger(DEBUG_TRAFFIC, LOG_WARNING, "Received packet from %s (%s) with MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
+       }
+
+       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) {
+                       return false;
+               } else {
+                       inpkt.len = len + offset;
+               }
+               if(inpkt.len > MAXSIZE)
+                       abort();
+       } else {
+               memcpy(inpkt.data + offset, data, len);
+               inpkt.len = len + offset;
+       }
+
+       /* Generate the Ethernet packet type if necessary */
+       if(offset) {
+               switch(inpkt.data[14] >> 4) {
+                       case 4:
+                               inpkt.data[12] = 0x08;
+                               inpkt.data[13] = 0x00;
+                               break;
+                       case 6:
+                               inpkt.data[12] = 0x86;
+                               inpkt.data[13] = 0xDD;
+                               break;
+                       default:
+                               logger(DEBUG_TRAFFIC, LOG_ERR,
+                                                  "Unknown IP version %d while reading packet from %s (%s)",
+                                                  inpkt.data[14] >> 4, from->name, from->hostname);
+                               return false;
+               }
+       }
+
+       receive_packet(from, &inpkt);
+       return true;
+}
+
 /*
   send a packet to the given vpn ip.
 */
-void send_packet(const node_t *n, vpn_packet_t *packet) {
+void send_packet(node_t *n, vpn_packet_t *packet) {
        node_t *via;
 
-       cp();
-
        if(n == myself) {
                if(overwrite_mac)
                         memcpy(packet->data, mymac.x, ETH_ALEN);
-               write_packet(packet);
+               n->out_packets++;
+               n->out_bytes += packet->len;
+               devops.write(packet);
                return;
        }
 
-       ifdebug(TRAFFIC) logger(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
+       logger(DEBUG_TRAFFIC, LOG_ERR, "Sending packet of %d bytes to %s (%s)",
                           packet->len, n->name, n->hostname);
 
        if(!n->status.reachable) {
-               ifdebug(TRAFFIC) logger(LOG_INFO, _("Node %s (%s) is not reachable"),
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Node %s (%s) is not reachable",
                                   n->name, n->hostname);
                return;
        }
 
+       n->out_packets++;
+       n->out_bytes += packet->len;
+
+       if(n->status.sptps) {
+               send_sptps_packet(n, packet);
+               return;
+       }
+
        via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
 
        if(via != n)
-               ifdebug(TRAFFIC) logger(LOG_INFO, _("Sending packet to %s via %s (%s)"),
+               logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet to %s via %s (%s)",
                           n->name, via->name, n->via->hostname);
 
        if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) {
@@ -426,60 +749,135 @@ void send_packet(const 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;
+       // Always give ourself a copy of the packet.
+       if(from != myself)
+               send_packet(myself, packet);
 
-       cp();
+       // In TunnelServer mode, do not forward broadcast packets.
+        // The MST might not be valid and create loops.
+       if(tunnelserver || broadcast_mode == BMODE_NONE)
+               return;
 
-       ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
+       logger(DEBUG_TRAFFIC, LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
                           packet->len, from->name, from->hostname);
 
-       if(from != myself)
-               send_packet(myself, packet);
+       switch(broadcast_mode) {
+               // In MST mode, broadcast packets travel via the Minimum Spanning Tree.
+               // This guarantees all nodes receive the broadcast packet, and
+               // usually distributes the sending of broadcast packets over all nodes.
+               case BMODE_MST:
+                       for(list_node_t *node = connection_list->head, *next; node; node = next) {
+                               next = node->next;
+                               connection_t *c = node->data;
+
+                               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.
+               // We don't have enough information to forward broadcast packets in this case.
+               case BMODE_DIRECT:
+                       if(from != myself)
+                               break;
 
-       for(node = connection_tree->head; node; node = node->next) {
-               c = node->data;
+                       for(splay_node_t *node = node_tree->head; node; node = node->next) {
+                               node_t *n = node->data;
 
-               if(c->status.active && c->status.mst && c != from->nexthop->connection)
-                       send_packet(c->node, packet);
+                               if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n))
+                                       send_packet(n, packet);
+                       }
+                       break;
+
+               default:
+                       break;
        }
 }
 
-void handle_incoming_vpn_data(int sock, short events, void *data)
-{
+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;
+
+               if(!e->to->status.reachable || e->to == myself)
+                       continue;
+
+               if(sockaddrcmp_noport(from, &e->address)) {
+                       if(last_hard_try == now)
+                               continue;
+                       hard = true;
+               }
+
+               if(!try_mac(e->to, pkt))
+                       continue;
+
+               n = e->to;
+               break;
+       }
+
+       if(hard)
+               last_hard_try = now;
+
+       last_hard_try = now;
+       return n;
+}
+
+void handle_incoming_vpn_data(int sock, short events, void *data) {
        vpn_packet_t pkt;
        char *hostname;
-       sockaddr_t from;
+       sockaddr_t from = {{0}};
        socklen_t fromlen = sizeof from;
        node_t *n;
+       int len;
 
-       cp();
-
-       pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+       len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
-       if(pkt.len < 0) {
-               logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
+       if(len <= 0 || len > MAXSIZE) {
+               if(!sockwouldblock(sockerrno))
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
                return;
        }
 
+       pkt.len = len;
+
        sockaddrunmap(&from);           /* Some braindead IPv6 implementations do stupid things. */
 
        n = lookup_node_udp(&from);
 
        if(!n) {
-               hostname = sockaddr2hostname(&from);
-               logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
-                          hostname);
-               free(hostname);
-               return;
+               n = try_harder(&from, &pkt);
+               if(n)
+                       update_node_udp(n, &from);
+               else if(debug_level >= DEBUG_PROTOCOL) {
+                       hostname = sockaddr2hostname(&from);
+                       logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
+                       free(hostname);
+                       return;
+               }
+               else
+                       return;
        }
 
+       n->sock = (intptr_t)data;
+
        receive_udppacket(n, &pkt);
 }
 
 void handle_device_data(int sock, short events, void *data) {
        vpn_packet_t packet;
 
-       if(read_packet(&packet))
+       packet.priority = 0;
+
+       if(devops.read(&packet)) {
+               myself->in_packets++;
+               myself->in_bytes += packet.len;
                route(myself, &packet);
+       }
 }