]> git.meshlink.io Git - meshlink/blobdiff - src/net_packet.c
Avoid allocating packet buffers unnecessarily.
[meshlink] / src / net_packet.c
index 9024f262cafc4734fb070cc9c5673763a840bb53..8aca6aa59adda1ef8f78d9eecec914625a9a367a 100644 (file)
@@ -1,9 +1,6 @@
 /*
     net_packet.c -- Handles in- and outgoing VPN packets
-    Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2013 Guus Sliepen <guus@tinc-vpn.org>
-                  2010      Timothy Redaelli <timothy@redaelli.eu>
-                  2010      Brandon Black <blblack@gmail.com>
+    Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
 
     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
 
 #include "system.h"
 
-#ifdef HAVE_ZLIB
-#include <zlib.h>
-#endif
-
-#ifdef HAVE_LZO
-#include LZO1X_H
-#endif
-
-#include "cipher.h"
 #include "conf.h"
 #include "connection.h"
 #include "crypto.h"
-#include "digest.h"
-#include "device.h"
-#include "ethernet.h"
 #include "graph.h"
 #include "logger.h"
+#include "meshlink_internal.h"
 #include "net.h"
 #include "netutl.h"
 #include "protocol.h"
-#include "process.h"
 #include "route.h"
 #include "utils.h"
 #include "xalloc.h"
 
 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;
+static void send_udppacket(meshlink_handle_t *mesh, node_t *, vpn_packet_t *);
 
 #define MAX_SEQNO 1073741824
 
@@ -75,14 +54,15 @@ bool localdiscovery = false;
 
 */
 
-static void send_mtu_probe_handler(void *data) {
+static void send_mtu_probe_handler(event_loop_t *loop, void *data) {
+       meshlink_handle_t *mesh = loop->data;
        node_t *n = data;
        int timeout = 1;
 
        n->mtuprobes++;
 
        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);
+               logger(mesh, MESHLINK_INFO, "Trying to send MTU probe to unreachable or rekeying node %s", n->name);
                n->mtuprobes = 0;
                return;
        }
@@ -90,95 +70,103 @@ static void send_mtu_probe_handler(void *data) {
        if(n->mtuprobes > 32) {
                if(!n->minmtu) {
                        n->mtuprobes = 31;
-                       timeout = pinginterval;
+                       timeout = mesh->dev_class_traits[n->devclass].pinginterval;
                        goto end;
                }
 
-               logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
+               logger(mesh, MESHLINK_INFO, "%s did not respond to UDP ping, restarting PMTU discovery", n->name);
                n->status.udp_confirmed = false;
                n->mtuprobes = 1;
                n->minmtu = 0;
                n->maxmtu = MTU;
+
+               update_node_pmtu(mesh, n);
        }
 
        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);
+               logger(mesh, MESHLINK_INFO, "No response to MTU probes from %s", n->name);
                n->mtuprobes = 31;
        }
 
        if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
-               if(n->minmtu > n->maxmtu)
+               if(n->minmtu > n->maxmtu) {
                        n->minmtu = n->maxmtu;
-               else
+                       update_node_pmtu(mesh, n);
+               } 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);
+               logger(mesh, MESHLINK_INFO, "Fixing MTU of %s to %d after %d probes", n->name, n->mtu, n->mtuprobes);
                n->mtuprobes = 31;
        }
 
        if(n->mtuprobes == 31) {
-               timeout = pinginterval;
+               if(!n->minmtu && n->status.want_udp) {
+                       /* Send a dummy ANS_KEY to try to update the reflexive UDP address */
+                       send_request(mesh, n->nexthop->connection, NULL, "%d %s %s . -1 -1 -1 0", ANS_KEY, mesh->self->name, n->name);
+                       n->status.want_udp = false;
+               }
+
+               timeout = mesh->dev_class_traits[n->devclass].pinginterval;
                goto end;
        } else if(n->mtuprobes == 32) {
-               timeout = pingtimeout;
+               timeout = mesh->dev_class_traits[n->devclass].pingtimeout;
        }
 
-       for(int i = 0; i < 4 + localdiscovery; i++) {
+       for(int i = 0; i < 5; i++) {
                int len;
 
                if(i == 0) {
-                       if(n->mtuprobes < 30 || n->maxmtu + 8 >= MTU)
+                       if(n->mtuprobes < 30 || n->maxmtu + 8 >= MTU) {
                                continue;
+                       }
+
                        len = n->maxmtu + 8;
                } else if(n->maxmtu <= n->minmtu) {
                        len = n->maxmtu;
                } else {
-                       len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+                       len = n->minmtu + 1 + prng(mesh, n->maxmtu - n->minmtu);
                }
 
-               if(len < 64)
+               if(len < 64) {
                        len = 64;
+               }
 
                vpn_packet_t packet;
+               packet.probe = true;
                memset(packet.data, 0, 14);
                randomize(packet.data + 14, len - 14);
                packet.len = len;
-               if(i >= 4 && n->mtuprobes <= 10)
-                       packet.priority = -1;
-               else
-                       packet.priority = 0;
+               n->status.broadcast = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
 
-               logger(DEBUG_TRAFFIC, LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
+               logger(mesh, MESHLINK_DEBUG, "Sending MTU probe length %d to %s", len, n->name);
 
-               send_udppacket(n, &packet);
+               send_udppacket(mesh, 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;
+       n->status.broadcast = false;
 
 end:
-       timeout_set(&n->mtutimeout, &(struct timeval){timeout, rand() % 100000});
+       timeout_set(&mesh->loop, &n->mtutimeout, &(struct timespec) {
+               timeout, prng(mesh, TIMER_FUDGE)
+       });
 }
 
-void send_mtu_probe(node_t *n) {
-       timeout_add(&n->mtutimeout, send_mtu_probe_handler, n, &(struct timeval){1, 0});
-       send_mtu_probe_handler(n);
+void send_mtu_probe(meshlink_handle_t *mesh, node_t *n) {
+       timeout_add(&mesh->loop, &n->mtutimeout, send_mtu_probe_handler, n, &(struct timespec) {
+               1, 0
+       });
+       send_mtu_probe_handler(&mesh->loop, 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);
+static void mtu_probe_h(meshlink_handle_t *mesh, node_t *n, vpn_packet_t *packet, uint16_t len) {
+       if(len < 64) {
+               logger(mesh, MESHLINK_WARNING, "Got too short MTU probe length %d from %s", packet->len, n->name);
+               return;
+       }
+
+       logger(mesh, MESHLINK_DEBUG, "Got MTU probe length %d from %s", packet->len, n->name);
 
        if(!packet->data[0]) {
                /* It's a probe request, send back a reply */
@@ -190,335 +178,133 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 
                bool udp_confirmed = n->status.udp_confirmed;
                n->status.udp_confirmed = true;
-               send_udppacket(n, packet);
+               send_udppacket(mesh, 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(!n->status.udp_confirmed) {
+                       char *address, *port;
+                       sockaddr2str(&n->address, &address, &port);
+                       send_request(mesh, n->nexthop->connection, NULL, "%d %s %s . -1 -1 -1 0 %s %s", ANS_KEY, n->name, n->name, address, port);
+                       free(address);
+                       free(port);
+                       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);
+                       if(len == n->maxmtu + 8) {
+                               logger(mesh, MESHLINK_INFO, "Increase in PMTU to %s detected, restarting PMTU discovery", n->name);
                                n->maxmtu = MTU;
                                n->mtuprobes = 10;
                                return;
                        }
 
-                       if(n->minmtu)
+                       if(n->minmtu) {
                                n->mtuprobes = 30;
-                       else
+                       } else {
                                n->mtuprobes = 1;
+                       }
                }
 
                /* If applicable, raise the minimum supported MTU */
 
-               if(len > n->maxmtu)
+               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);
                }
-       }
-}
 
-static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
-       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
+               if(n->minmtu < len) {
+                       n->minmtu = len;
+                       update_node_pmtu(mesh, n);
+               }
        }
-
-       return -1;
-}
-
-static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
-       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;
-       }
-#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) {
-       logger(DEBUG_TRAFFIC, LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
-                          packet->len, n->name, n->hostname);
+static void receive_packet(meshlink_handle_t *mesh, node_t *n, vpn_packet_t *packet) {
+       logger(mesh, MESHLINK_DEBUG, "Received packet of %d bytes from %s", packet->len, n->name);
 
-       n->in_packets++;
-       n->in_bytes += packet->len;
+       if(n->status.blacklisted) {
+               logger(mesh, MESHLINK_WARNING, "Dropping packet from blacklisted node %s", n->name);
+       } else {
+               n->in_packets++;
+               n->in_bytes += packet->len;
 
-       route(n, packet);
+               route(mesh, 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 - digest_length(n->indigest), (const char *)&inpkt->seqno + inpkt->len - digest_length(n->indigest));
+static bool try_mac(meshlink_handle_t *mesh, node_t *n, const vpn_packet_t *inpkt) {
+       (void)mesh;
+       return sptps_verify_datagram(&n->sptps, inpkt->data, inpkt->len);
 }
 
-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;
-
-       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(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(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)) {
-               outpkt = pkt[nextpkt++];
-               outlen = MAXSIZE;
-
-               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;
-       }
-
-       /* Check the sequence number */
-
-       inpkt->len -= sizeof inpkt->seqno;
-       inpkt->seqno = ntohl(inpkt->seqno);
-
-       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;
-                       }
+static void receive_udppacket(meshlink_handle_t *mesh, node_t *n, vpn_packet_t *inpkt) {
+       if(!n->sptps.state) {
+               if(!n->status.waitingforkey) {
+                       logger(mesh, MESHLINK_DEBUG, "Got packet from %s but we haven't exchanged keys yet", n->name);
+                       send_req_key(mesh, n);
+               } else {
+                       logger(mesh, MESHLINK_DEBUG, "Got packet from %s but he hasn't got our key yet", n->name);
                }
 
-               n->farfuture = 0;
-               n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
+               return;
        }
 
-       if(inpkt->seqno > n->received_seqno)
-               n->received_seqno = inpkt->seqno;
-
-       n->received++;
-
-       if(n->received_seqno > MAX_SEQNO)
-               regenerate_key();
-
-       /* Decompress the packet */
-
-       length_t origlen = inpkt->len;
-
-       if(n->incompression) {
-               outpkt = pkt[nextpkt++];
-
-               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;
+       if(!sptps_receive_data(&n->sptps, inpkt->data, inpkt->len)) {
+               logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", n->name, strerror(errno));
        }
-
-       inpkt->priority = 0;
-
-       if(!inpkt->data[12] && !inpkt->data[13])
-               mtu_probe_h(n, inpkt, origlen);
-       else
-               receive_packet(n, 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;
-       else
-               outpkt.priority = -1;
-       memcpy(outpkt.data, buffer, len);
-
-       receive_packet(c->node, &outpkt);
 }
 
-static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
+static void send_sptps_packet(meshlink_handle_t *mesh, 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 < now.tv_sec) {
-                       logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
+               logger(mesh, MESHLINK_INFO, "No valid key known yet for %s", n->name);
+
+               if(!n->status.waitingforkey) {
+                       send_req_key(mesh, n);
+               } else if(n->last_req_key + 10 < mesh->loop.now.tv_sec) {
+                       logger(mesh, MESHLINK_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
                        sptps_stop(&n->sptps);
                        n->status.waitingforkey = false;
-                       send_req_key(n);
+                       send_req_key(mesh, 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);
+       // If it's a probe, send it immediately without trying to compress it.
+       if(origpkt->probe) {
+               sptps_send_record(&n->sptps, PKT_PROBE, 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);
+       sptps_send_record(&n->sptps, type, origpkt->data, origpkt->len);
        return;
 }
 
-static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+static void choose_udp_address(meshlink_handle_t *mesh, 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)
+       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;
+       if(++mesh->udp_choice >= 3) {
+               mesh->udp_choice = 0;
                return;
        }
 
@@ -526,7 +312,7 @@ static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock
           So we pick a random edge and a random socket. */
 
        int i = 0;
-       int j = rand() % n->edge_tree->count;
+       int j = prng(mesh, n->edge_tree->count);
        edge_t *candidate = NULL;
 
        for splay_each(edge_t, e, n->edge_tree) {
@@ -538,13 +324,13 @@ static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock
 
        if(candidate) {
                *sa = &candidate->address;
-               *sock = rand() % listen_sockets;
+               *sock = prng(mesh, mesh->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) {
+       if(mesh->listen_socket[*sock].sa.sa.sa_family != (*sa)->sa.sa_family) {
+               for(int i = 0; i < mesh->listen_sockets; i++) {
+                       if(mesh->listen_socket[i].sa.sa.sa_family == (*sa)->sa.sa_family) {
                                *sock = i;
                                break;
                        }
@@ -552,181 +338,49 @@ static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock
        }
 }
 
-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;
+static void choose_broadcast_address(meshlink_handle_t *mesh, const node_t *n, const sockaddr_t **sa, int *sock) {
+       *sock = prng(mesh, mesh->listen_sockets);
+       sockaddr_t *broadcast_sa = &mesh->listen_socket[*sock].broadcast_sa;
 
-       if(listen_socket[*sock].sa.sa.sa_family == AF_INET6) {
-               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;
+       if(broadcast_sa->sa.sa_family == AF_INET6) {
+               broadcast_sa->in6.sin6_port = n->prevedge->address.in.sin_port;
        } else {
-               broadcast_ipv4.in.sin_port = n->prevedge->address.in.sin_port;
-               *sa = &broadcast_ipv4;
+               broadcast_sa->in.sin_port = n->prevedge->address.in.sin_port;
        }
-}
 
-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 = origpkt->len;
-       size_t outlen;
-#if defined(SOL_IP) && defined(IP_TOS)
-       static int priority = 0;
-#endif
-       int origpriority = origpkt->priority;
+       *sa = broadcast_sa;
+}
 
+static void send_udppacket(meshlink_handle_t *mesh, 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)
-               return send_sptps_packet(n, origpkt);
-
-       /* 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);
-
-               if(n->last_req_key + 10 <= now.tv_sec) {
-                       send_req_key(n);
-                       n->last_req_key = now.tv_sec;
-               }
-
-               send_tcppacket(n->nexthop->connection, origpkt);
-
+               logger(mesh, MESHLINK_INFO, "Trying to send UDP packet to unreachable node %s", n->name);
                return;
        }
 
-       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");
-
-               if(n != n->nexthop)
-                       send_packet(n->nexthop, origpkt);
-               else
-                       send_tcppacket(n->nexthop->connection, origpkt);
-
-               return;
-       }
-
-       /* Compress the packet */
-
-       if(n->outcompression) {
-               outpkt = pkt[nextpkt++];
-
-               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;
-               }
-
-               inpkt = outpkt;
-       }
-
-       /* Add sequence number */
-
-       inpkt->seqno = htonl(++(n->sent_seqno));
-       inpkt->len += sizeof inpkt->seqno;
-
-       /* Encrypt the packet */
-
-       if(cipher_active(n->outcipher)) {
-               outpkt = pkt[nextpkt++];
-               outlen = MAXSIZE;
-
-               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;
-               }
-
-               outpkt->len = outlen;
-               inpkt = outpkt;
-       }
-
-       /* Add the message authentication code */
-
-       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 */
-
-       const sockaddr_t *sa;
-       int sock;
-
-       /* Overloaded use of priority field: -1 means local broadcast */
-
-       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.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.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;
-                       if(n->mtu >= origlen)
-                               n->mtu = origlen - 1;
-               } else
-                       logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
-       }
-
-end:
-       origpkt->len = origlen;
+       send_sptps_packet(mesh, n, origpkt);
 }
 
-bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
+bool send_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
+       assert(handle);
+       assert(data);
+       assert(len);
+
        node_t *to = handle;
+       meshlink_handle_t *mesh = to->mesh;
 
        /* 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)) {
+       if(type >= SPTPS_HANDSHAKE || (type != PKT_PROBE && (len - 21) > 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);
+               if(!to->status.validkey) {
+                       return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, mesh->self->name, to->name, buf, 0);
+               } else {
+                       return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_SPTPS, buf);
+               }
        }
 
        /* Otherwise, send the packet via UDP */
@@ -734,16 +388,23 @@ bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
        const sockaddr_t *sa;
        int sock;
 
-       choose_udp_address(to, &sa, &sock);
+       if(to->status.broadcast) {
+               choose_broadcast_address(mesh, to, &sa, &sock);
+       } else {
+               choose_udp_address(mesh, to, &sa, &sock);
+       }
 
-       if(sendto(listen_socket[sock].udp.fd, data, len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
+       if(sendto(mesh->listen_socket[sock].udp.fd, data, len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
                if(sockmsgsize(sockerrno)) {
-                       if(to->maxmtu >= len)
+                       if(to->maxmtu >= len) {
                                to->maxmtu = len - 1;
-                       if(to->mtu >= len)
+                       }
+
+                       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));
+                       logger(mesh, MESHLINK_WARNING, "Error sending UDP SPTPS packet to %s: %s", to->name, sockstrerror(sockerrno));
                        return false;
                }
        }
@@ -751,20 +412,29 @@ bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
        return true;
 }
 
-bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t len) {
+bool receive_sptps_record(void *handle, uint8_t type, const void *data, uint16_t len) {
+       assert(handle);
+       assert(!data || len);
+
        node_t *from = handle;
+       meshlink_handle_t *mesh = from->mesh;
 
        if(type == SPTPS_HANDSHAKE) {
                if(!from->status.validkey) {
+                       logger(mesh, MESHLINK_INFO, "SPTPS key exchange with %s successful", from->name);
                        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->utcp) {
+                               utcp_reset_timers(from->utcp);
+                       }
                }
+
                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);
+       if(len > MAXSIZE) {
+               logger(mesh, MESHLINK_ERROR, "Packet from %s larger than maximum supported size (%d > %d)", from->name, len, MAXSIZE);
                return false;
        }
 
@@ -772,192 +442,109 @@ bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t
 
        if(type == PKT_PROBE) {
                inpkt.len = len;
+               inpkt.probe = true;
                memcpy(inpkt.data, data, len);
-               mtu_probe_h(from, &inpkt, len);
+               mtu_probe_h(mesh, from, &inpkt, len);
                return true;
+       } else {
+               inpkt.probe = false;
        }
 
-       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);
+       if(type & ~(PKT_COMPRESSED)) {
+               logger(mesh, MESHLINK_ERROR, "Unexpected SPTPS record type %d len %d from %s", type, len, from->name);
                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) {
-               length_t ulen = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
-               if(ulen < 0) {
-                       return false;
-               } else {
-                       inpkt.len = ulen + offset;
-               }
-               if(inpkt.len > MAXSIZE)
-                       abort();
-       } else {
-               memcpy(inpkt.data + offset, data, len);
-               inpkt.len = len + offset;
+               logger(mesh, MESHLINK_ERROR, "Error while decompressing packet from %s", from->name);
+               return false;
        }
 
-       /* 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;
-               }
-       }
+       memcpy(inpkt.data, data, len); // TODO: get rid of memcpy
+       inpkt.len = len;
 
-       receive_packet(from, &inpkt);
+       receive_packet(mesh, from, &inpkt);
        return true;
 }
 
 /*
   send a packet to the given vpn ip.
 */
-void send_packet(node_t *n, vpn_packet_t *packet) {
-       node_t *via;
-
-       if(n == myself) {
-               if(overwrite_mac)
-                        memcpy(packet->data, mymac.x, ETH_ALEN);
+void send_packet(meshlink_handle_t *mesh, node_t *n, vpn_packet_t *packet) {
+       if(n == mesh->self) {
                n->out_packets++;
                n->out_bytes += packet->len;
-               devops.write(packet);
+               // TODO: send to application
                return;
        }
 
-       logger(DEBUG_TRAFFIC, LOG_ERR, "Sending packet of %d bytes to %s (%s)",
-                          packet->len, n->name, n->hostname);
+       logger(mesh, MESHLINK_DEBUG, "Sending packet of %d bytes to %s", packet->len, n->name);
 
        if(!n->status.reachable) {
-               logger(DEBUG_TRAFFIC, LOG_INFO, "Node %s (%s) is not reachable",
-                                  n->name, n->hostname);
+               logger(mesh, MESHLINK_WARNING, "Node %s is not reachable", n->name);
                return;
        }
 
        n->out_packets++;
        n->out_bytes += packet->len;
+       n->status.want_udp = true;
 
-       if(n->status.sptps) {
-               send_sptps_packet(n, packet);
-               return;
-       }
-
-       via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
-
-       if(via != n)
-               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)) {
-               if(!send_tcppacket(via->connection, packet))
-                       terminate_connection(via->connection, true);
-       } else
-               send_udppacket(via, packet);
-}
-
-/* Broadcast a packet using the minimum spanning tree */
-
-void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
-       // 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.
-       if(tunnelserver || broadcast_mode == BMODE_NONE)
-               return;
-
-       logger(DEBUG_TRAFFIC, LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
-                          packet->len, from->name, from->hostname);
-
-       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_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.
-               // We don't have enough information to forward broadcast packets in this case.
-               case BMODE_DIRECT:
-                       if(from != myself)
-                               break;
-
-                       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:
-                       break;
-       }
+       send_sptps_packet(mesh, n, packet);
+       return;
 }
 
-static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
+static node_t *try_harder(meshlink_handle_t *mesh, const sockaddr_t *from, const vpn_packet_t *pkt) {
        node_t *n = NULL;
        bool hard = false;
-       static time_t last_hard_try = 0;
 
-       for splay_each(edge_t, e, edge_weight_tree) {
-               if(!e->to->status.reachable || e->to == myself)
+       for splay_each(edge_t, e, mesh->edges) {
+               if(!e->to->status.reachable || e->to == mesh->self) {
                        continue;
+               }
 
                if(sockaddrcmp_noport(from, &e->address)) {
-                       if(last_hard_try == now.tv_sec)
+                       if(mesh->last_hard_try == mesh->loop.now.tv_sec) {
                                continue;
+                       }
+
                        hard = true;
                }
 
-               if(!try_mac(e->to, pkt))
+               if(!try_mac(mesh, e->to, pkt)) {
                        continue;
+               }
 
                n = e->to;
                break;
        }
 
-       if(hard)
-               last_hard_try = now.tv_sec;
+       if(hard) {
+               mesh->last_hard_try = mesh->loop.now.tv_sec;
+       }
 
-       last_hard_try = now.tv_sec;
        return n;
 }
 
-void handle_incoming_vpn_data(void *data, int flags) {
+void handle_incoming_vpn_data(event_loop_t *loop, void *data, int flags) {
+       (void)flags;
+       meshlink_handle_t *mesh = loop->data;
        listen_socket_t *ls = data;
        vpn_packet_t pkt;
        char *hostname;
-       sockaddr_t from = {{0}};
-       socklen_t fromlen = sizeof from;
+       sockaddr_t from;
+       socklen_t fromlen = sizeof(from);
        node_t *n;
        int len;
 
-       len = recvfrom(ls->udp.fd, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+       memset(&from, 0, sizeof(from));
+
+       len = recvfrom(ls->udp.fd, pkt.data, MAXSIZE, 0, &from.sa, &fromlen);
 
        if(len <= 0 || len > MAXSIZE) {
-               if(!sockwouldblock(sockerrno))
-                       logger(DEBUG_ALWAYS, LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
+               if(!sockwouldblock(sockerrno)) {
+                       logger(mesh, MESHLINK_ERROR, "Receiving packet failed: %s", sockstrerror(sockerrno));
+               }
+
                return;
        }
 
@@ -965,35 +552,29 @@ void handle_incoming_vpn_data(void *data, int flags) {
 
        sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
 
-       n = lookup_node_udp(&from);
+       n = lookup_node_udp(mesh, &from);
 
        if(!n) {
-               n = try_harder(&from, &pkt);
-               if(n)
-                       update_node_udp(n, &from);
-               else if(debug_level >= DEBUG_PROTOCOL) {
+               n = try_harder(mesh, &from, &pkt);
+
+               if(n) {
+                       update_node_udp(mesh, n, &from);
+               } else if(mesh->log_level <= MESHLINK_WARNING) {
                        hostname = sockaddr2hostname(&from);
-                       logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
+                       logger(mesh, MESHLINK_WARNING, "Received UDP packet from unknown source %s", hostname);
                        free(hostname);
                        return;
-               }
-               else
+               } else {
                        return;
+               }
        }
 
-       n->sock = ls - listen_socket;
-
-       receive_udppacket(n, &pkt);
-}
-
-void handle_device_data(void *data, int flags) {
-       vpn_packet_t packet;
+       if(n->status.blacklisted) {
+               logger(mesh, MESHLINK_WARNING, "Dropping packet from blacklisted node %s", n->name);
+               return;
+       }
 
-       packet.priority = 0;
+       n->sock = ls - mesh->listen_socket;
 
-       if(devops.read(&packet)) {
-               myself->in_packets++;
-               myself->in_bytes += packet.len;
-               route(myself, &packet);
-       }
+       receive_udppacket(mesh, n, &pkt);
 }