2 net_packet.c -- Handles in- and outgoing VPN packets
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2013 Guus Sliepen <guus@tinc-vpn.org>
5 2010 Timothy Redaelli <timothy@redaelli.eu>
6 2010 Brandon Black <blblack@gmail.com>
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
35 #include "connection.h"
51 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
54 static void send_udppacket(node_t *, vpn_packet_t *);
56 unsigned replaywin = 16;
57 bool localdiscovery = false;
58 sockaddr_t localdiscovery_address;
60 #define MAX_SEQNO 1073741824
62 /* mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
63 mtuprobes == 31: sleep pinginterval seconds
64 mtuprobes == 32: send 1 burst, sleep pingtimeout second
65 mtuprobes == 33: no response from other side, restart PMTU discovery process
67 Probes are sent in batches of at least three, with random sizes between the
68 lower and upper boundaries for the MTU thus far discovered.
70 After the initial discovery, a fourth packet is added to each batch with a
71 size larger than the currently known PMTU, to test if the PMTU has increased.
73 In case local discovery is enabled, another packet is added to each batch,
74 which will be broadcast to the local network.
78 static void send_mtu_probe_handler(void *data) {
84 if(!n->status.reachable || !n->status.validkey) {
85 logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
90 if(n->mtuprobes > 32) {
93 timeout = pinginterval;
97 logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
98 n->status.udp_confirmed = false;
104 if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
105 logger(DEBUG_TRAFFIC, LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
109 if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
110 if(n->minmtu > n->maxmtu)
111 n->minmtu = n->maxmtu;
113 n->maxmtu = n->minmtu;
115 logger(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
119 if(n->mtuprobes == 31) {
120 timeout = pinginterval;
122 } else if(n->mtuprobes == 32) {
123 timeout = pingtimeout;
126 for(int i = 0; i < 4 + localdiscovery; i++) {
130 if(n->mtuprobes < 30 || n->maxmtu + 8 >= MTU)
133 } else if(n->maxmtu <= n->minmtu) {
136 len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
143 memset(packet.data, 0, 14);
144 randomize(packet.data + 14, len - 14);
147 n->status.broadcast = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
149 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
151 send_udppacket(n, &packet);
154 n->status.broadcast = false;
155 n->probe_counter = 0;
156 gettimeofday(&n->probe_time, NULL);
158 /* Calculate the packet loss of incoming traffic by comparing the rate of
159 packets received to the rate with which the sequence number has increased.
162 if(n->received > n->prev_received)
163 n->packetloss = 1.0 - (n->received - n->prev_received) / (float)(n->received_seqno - n->prev_received_seqno);
165 n->packetloss = n->received_seqno <= n->prev_received_seqno;
167 n->prev_received_seqno = n->received_seqno;
168 n->prev_received = n->received;
171 timeout_set(&n->mtutimeout, &(struct timeval){timeout, rand() % 100000});
174 void send_mtu_probe(node_t *n) {
175 timeout_add(&n->mtutimeout, send_mtu_probe_handler, n, &(struct timeval){1, 0});
176 send_mtu_probe_handler(n);
179 static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
180 if(!packet->data[0]) {
181 logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe request %d from %s (%s)", packet->len, n->name, n->hostname);
183 /* It's a probe request, send back a reply */
185 /* Type 2 probe replies were introduced in protocol 17.3 */
186 if ((n->options >> 24) == 3) {
187 uint8_t* data = packet->data;
189 uint16_t len16 = htons(len); memcpy(data, &len16, 2); data += 2;
191 gettimeofday(&now, NULL);
192 uint32_t sec = htonl(now.tv_sec); memcpy(data, &sec, 4); data += 4;
193 uint32_t usec = htonl(now.tv_usec); memcpy(data, &usec, 4); data += 4;
194 packet->len = data - packet->data;
196 /* Legacy protocol: n won't understand type 2 probe replies. */
200 /* Temporarily set udp_confirmed, so that the reply is sent
201 back exactly the way it came in. */
203 bool udp_confirmed = n->status.udp_confirmed;
204 n->status.udp_confirmed = true;
205 send_udppacket(n, packet);
206 n->status.udp_confirmed = udp_confirmed;
208 length_t probelen = len;
209 if (packet->data[0] == 2) {
211 logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) MTU probe reply from %s (%s)", n->name, n->hostname);
213 uint16_t probelen16; memcpy(&probelen16, packet->data + 1, 2); probelen = ntohs(probelen16);
216 logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d MTU probe reply %d from %s (%s)", packet->data[0], probelen, n->name, n->hostname);
218 /* It's a valid reply: now we know bidirectional communication
219 is possible using the address and socket that the reply
222 n->status.udp_confirmed = true;
224 /* If we haven't established the PMTU yet, restart the discovery process. */
226 if(n->mtuprobes > 30) {
227 if (probelen == n->maxmtu + 8) {
228 logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
240 /* If applicable, raise the minimum supported MTU */
242 if(probelen > n->maxmtu)
243 probelen = n->maxmtu;
244 if(n->minmtu < probelen)
245 n->minmtu = probelen;
247 /* Calculate RTT and bandwidth.
248 The RTT is the time between the MTU probe burst was sent and the first
249 reply is received. The bandwidth is measured using the time between the
250 arrival of the first and third probe reply (or type 2 probe requests).
253 struct timeval now, diff;
254 gettimeofday(&now, NULL);
255 timersub(&now, &n->probe_time, &diff);
257 struct timeval probe_timestamp = now;
258 if (packet->data[0] == 2 && packet->len >= 11) {
259 uint32_t sec; memcpy(&sec, packet->data + 3, 4);
260 uint32_t usec; memcpy(&usec, packet->data + 7, 4);
261 probe_timestamp.tv_sec = ntohl(sec);
262 probe_timestamp.tv_usec = ntohl(usec);
267 if(n->probe_counter == 1) {
268 n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
269 n->probe_time = probe_timestamp;
270 } else if(n->probe_counter == 3) {
271 struct timeval probe_timestamp_diff;
272 timersub(&probe_timestamp, &n->probe_time, &probe_timestamp_diff);
273 n->bandwidth = 2.0 * probelen / (probe_timestamp_diff.tv_sec + probe_timestamp_diff.tv_usec * 1e-6);
274 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);
279 static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
281 memcpy(dest, source, len);
283 } else if(level == 10) {
285 lzo_uint lzolen = MAXSIZE;
286 lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
291 } else if(level < 10) {
293 unsigned long destlen = MAXSIZE;
294 if(compress2(dest, &destlen, source, len, level) == Z_OK)
301 lzo_uint lzolen = MAXSIZE;
302 lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
312 static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
314 memcpy(dest, source, len);
316 } else if(level > 9) {
318 lzo_uint lzolen = MAXSIZE;
319 if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
327 unsigned long destlen = MAXSIZE;
328 if(uncompress(dest, &destlen, source, len) == Z_OK)
340 static void receive_packet(node_t *n, vpn_packet_t *packet) {
341 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
342 packet->len, n->name, n->hostname);
345 n->in_bytes += packet->len;
350 static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
352 return sptps_verify_datagram(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
354 if(!digest_active(n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest))
357 return digest_verify(n->indigest, &inpkt->seqno, inpkt->len - digest_length(n->indigest), (const char *)&inpkt->seqno + inpkt->len - digest_length(n->indigest));
360 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
361 vpn_packet_t pkt1, pkt2;
362 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
364 vpn_packet_t *outpkt = pkt[0];
367 if(n->status.sptps) {
368 if(!n->sptps.state) {
369 if(!n->status.waitingforkey) {
370 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but we haven't exchanged keys yet", n->name, n->hostname);
373 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
377 sptps_receive_data(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
381 if(!n->status.validkey) {
382 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
386 /* Check packet length */
388 if(inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest)) {
389 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got too short packet from %s (%s)",
390 n->name, n->hostname);
394 /* Check the message authentication code */
396 if(digest_active(n->indigest)) {
397 inpkt->len -= digest_length(n->indigest);
398 if(!digest_verify(n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
399 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
403 /* Decrypt the packet */
405 if(cipher_active(n->incipher)) {
406 outpkt = pkt[nextpkt++];
409 if(!cipher_decrypt(n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
410 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
414 outpkt->len = outlen;
418 /* Check the sequence number */
420 inpkt->len -= sizeof inpkt->seqno;
421 inpkt->seqno = ntohl(inpkt->seqno);
424 if(inpkt->seqno != n->received_seqno + 1) {
425 if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
426 if(n->farfuture++ < replaywin >> 2) {
427 logger(DEBUG_ALWAYS, LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
428 n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture);
431 logger(DEBUG_ALWAYS, LOG_WARNING, "Lost %d packets from %s (%s)",
432 inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
433 memset(n->late, 0, replaywin);
434 } else if (inpkt->seqno <= n->received_seqno) {
435 if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
436 logger(DEBUG_ALWAYS, LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
437 n->name, n->hostname, inpkt->seqno, n->received_seqno);
441 for(int i = n->received_seqno + 1; i < inpkt->seqno; i++)
442 n->late[(i / 8) % replaywin] |= 1 << i % 8;
447 n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
450 if(inpkt->seqno > n->received_seqno)
451 n->received_seqno = inpkt->seqno;
455 if(n->received_seqno > MAX_SEQNO)
458 /* Decompress the packet */
460 length_t origlen = inpkt->len;
462 if(n->incompression) {
463 outpkt = pkt[nextpkt++];
465 if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
466 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
467 n->name, n->hostname);
473 origlen -= MTU/64 + 20;
478 if(!inpkt->data[12] && !inpkt->data[13])
479 mtu_probe_h(n, inpkt, origlen);
481 receive_packet(n, inpkt);
484 void receive_tcppacket(connection_t *c, const char *buffer, int len) {
487 if(len > sizeof outpkt.data)
491 if(c->options & OPTION_TCPONLY)
494 outpkt.priority = -1;
495 memcpy(outpkt.data, buffer, len);
497 receive_packet(c->node, &outpkt);
500 static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
501 if(!n->status.validkey) {
502 logger(DEBUG_TRAFFIC, LOG_INFO, "No valid key known yet for %s (%s)", n->name, n->hostname);
503 if(!n->status.waitingforkey)
505 else if(n->last_req_key + 10 < now.tv_sec) {
506 logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
507 sptps_stop(&n->sptps);
508 n->status.waitingforkey = false;
517 if(!(origpkt->data[12] | origpkt->data[13])) {
518 sptps_send_record(&n->sptps, PKT_PROBE, (char *)origpkt->data, origpkt->len);
522 if(routing_mode == RMODE_ROUTER)
527 if(origpkt->len < offset)
532 if(n->outcompression) {
533 int len = compress_packet(outpkt.data + offset, origpkt->data + offset, origpkt->len - offset, n->outcompression);
535 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)", n->name, n->hostname);
536 } else if(len < origpkt->len - offset) {
537 outpkt.len = len + offset;
539 type |= PKT_COMPRESSED;
543 sptps_send_record(&n->sptps, type, (char *)origpkt->data + offset, origpkt->len - offset);
547 static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock) {
552 /* If the UDP address is confirmed, use it. */
553 if(n->status.udp_confirmed)
556 /* Send every third packet to n->address; that could be set
557 to the node's reflexive UDP address discovered during key
566 /* Otherwise, address are found in edges to this node.
567 So we pick a random edge and a random socket. */
570 int j = rand() % n->edge_tree->count;
571 edge_t *candidate = NULL;
573 for splay_each(edge_t, e, n->edge_tree) {
575 candidate = e->reverse;
581 *sa = &candidate->address;
582 *sock = rand() % listen_sockets;
585 /* Make sure we have a suitable socket for the chosen address */
586 if(listen_socket[*sock].sa.sa.sa_family != (*sa)->sa.sa_family) {
587 for(int i = 0; i < listen_sockets; i++) {
588 if(listen_socket[i].sa.sa.sa_family == (*sa)->sa.sa_family) {
596 static void choose_broadcast_address(const node_t *n, const sockaddr_t **sa, int *sock) {
597 static sockaddr_t broadcast_ipv4 = {
599 .sin_family = AF_INET,
600 .sin_addr.s_addr = -1,
604 static sockaddr_t broadcast_ipv6 = {
606 .sin6_family = AF_INET6,
607 .sin6_addr.s6_addr[0x0] = 0xff,
608 .sin6_addr.s6_addr[0x1] = 0x02,
609 .sin6_addr.s6_addr[0xf] = 0x01,
613 *sock = rand() % listen_sockets;
615 if(listen_socket[*sock].sa.sa.sa_family == AF_INET6) {
616 if(localdiscovery_address.sa.sa_family == AF_INET6) {
617 localdiscovery_address.in6.sin6_port = n->prevedge->address.in.sin_port;
618 *sa = &localdiscovery_address;
620 broadcast_ipv6.in6.sin6_port = n->prevedge->address.in.sin_port;
621 broadcast_ipv6.in6.sin6_scope_id = listen_socket[*sock].sa.in6.sin6_scope_id;
622 *sa = &broadcast_ipv6;
625 if(localdiscovery_address.sa.sa_family == AF_INET) {
626 localdiscovery_address.in.sin_port = n->prevedge->address.in.sin_port;
627 *sa = &localdiscovery_address;
629 broadcast_ipv4.in.sin_port = n->prevedge->address.in.sin_port;
630 *sa = &broadcast_ipv4;
635 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
636 vpn_packet_t pkt1, pkt2;
637 vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
638 vpn_packet_t *inpkt = origpkt;
640 vpn_packet_t *outpkt;
641 int origlen = origpkt->len;
643 #if defined(SOL_IP) && defined(IP_TOS)
644 static int priority = 0;
646 int origpriority = origpkt->priority;
648 if(!n->status.reachable) {
649 logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
654 return send_sptps_packet(n, origpkt);
656 /* Make sure we have a valid key */
658 if(!n->status.validkey) {
659 logger(DEBUG_TRAFFIC, LOG_INFO,
660 "No valid key known yet for %s (%s), forwarding via TCP",
661 n->name, n->hostname);
663 if(n->last_req_key + 10 <= now.tv_sec) {
665 n->last_req_key = now.tv_sec;
668 send_tcppacket(n->nexthop->connection, origpkt);
673 if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
674 logger(DEBUG_TRAFFIC, LOG_INFO,
675 "Packet for %s (%s) larger than minimum MTU, forwarding via %s",
676 n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP");
679 send_packet(n->nexthop, origpkt);
681 send_tcppacket(n->nexthop->connection, origpkt);
686 /* Compress the packet */
688 if(n->outcompression) {
689 outpkt = pkt[nextpkt++];
691 if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
692 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)",
693 n->name, n->hostname);
700 /* Add sequence number */
702 inpkt->seqno = htonl(++(n->sent_seqno));
703 inpkt->len += sizeof inpkt->seqno;
705 /* Encrypt the packet */
707 if(cipher_active(n->outcipher)) {
708 outpkt = pkt[nextpkt++];
711 if(!cipher_encrypt(n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
712 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
716 outpkt->len = outlen;
720 /* Add the message authentication code */
722 if(digest_active(n->outdigest)) {
723 if(!digest_create(n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len)) {
724 logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
728 inpkt->len += digest_length(n->outdigest);
731 /* Send the packet */
733 const sockaddr_t *sa;
736 if(n->status.broadcast)
737 choose_broadcast_address(n, &sa, &sock);
739 choose_udp_address(n, &sa, &sock);
741 #if defined(SOL_IP) && defined(IP_TOS)
742 if(priorityinheritance && origpriority != priority
743 && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
744 priority = origpriority;
745 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
746 if(setsockopt(listen_socket[n->sock].udp.fd, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
747 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "setsockopt", sockstrerror(sockerrno));
751 if(sendto(listen_socket[sock].udp.fd, (char *) &inpkt->seqno, inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
752 if(sockmsgsize(sockerrno)) {
753 if(n->maxmtu >= origlen)
754 n->maxmtu = origlen - 1;
755 if(n->mtu >= origlen)
756 n->mtu = origlen - 1;
758 logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
762 origpkt->len = origlen;
765 bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
768 /* Send it via TCP if it is a handshake packet, TCPOnly is in use, or this packet is larger than the MTU. */
770 if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > to->minmtu)) {
771 char buf[len * 4 / 3 + 5];
772 b64encode(data, buf, len);
773 /* If no valid key is known yet, send the packets using ANS_KEY requests,
774 to ensure we get to learn the reflexive UDP address. */
775 if(!to->status.validkey) {
776 to->incompression = myself->incompression;
777 return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, to->incompression);
779 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_SPTPS, buf);
783 /* Otherwise, send the packet via UDP */
785 const sockaddr_t *sa;
788 if(to->status.broadcast)
789 choose_broadcast_address(to, &sa, &sock);
791 choose_udp_address(to, &sa, &sock);
793 if(sendto(listen_socket[sock].udp.fd, data, len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
794 if(sockmsgsize(sockerrno)) {
795 // Compensate for SPTPS overhead
796 len -= SPTPS_DATAGRAM_OVERHEAD;
797 if(to->maxmtu >= len)
798 to->maxmtu = len - 1;
802 logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", to->name, to->hostname, sockstrerror(sockerrno));
810 bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t len) {
811 node_t *from = handle;
813 if(type == SPTPS_HANDSHAKE) {
814 if(!from->status.validkey) {
815 from->status.validkey = true;
816 from->status.waitingforkey = false;
817 logger(DEBUG_META, LOG_INFO, "SPTPS key exchange with %s (%s) succesful", from->name, from->hostname);
823 logger(DEBUG_ALWAYS, LOG_ERR, "Packet from %s (%s) larger than maximum supported size (%d > %d)", from->name, from->hostname, len, MTU);
829 if(type == PKT_PROBE) {
831 memcpy(inpkt.data, data, len);
832 mtu_probe_h(from, &inpkt, len);
836 if(type & ~(PKT_COMPRESSED | PKT_MAC)) {
837 logger(DEBUG_ALWAYS, LOG_ERR, "Unexpected SPTPS record type %d len %d from %s (%s)", type, len, from->name, from->hostname);
841 /* Check if we have the headers we need */
842 if(routing_mode != RMODE_ROUTER && !(type & PKT_MAC)) {
843 logger(DEBUG_TRAFFIC, LOG_ERR, "Received packet from %s (%s) without MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
845 } else if(routing_mode == RMODE_ROUTER && (type & PKT_MAC)) {
846 logger(DEBUG_TRAFFIC, LOG_WARNING, "Received packet from %s (%s) with MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
849 int offset = (type & PKT_MAC) ? 0 : 14;
850 if(type & PKT_COMPRESSED) {
851 length_t ulen = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
855 inpkt.len = ulen + offset;
857 if(inpkt.len > MAXSIZE)
860 memcpy(inpkt.data + offset, data, len);
861 inpkt.len = len + offset;
864 /* Generate the Ethernet packet type if necessary */
866 switch(inpkt.data[14] >> 4) {
868 inpkt.data[12] = 0x08;
869 inpkt.data[13] = 0x00;
872 inpkt.data[12] = 0x86;
873 inpkt.data[13] = 0xDD;
876 logger(DEBUG_TRAFFIC, LOG_ERR,
877 "Unknown IP version %d while reading packet from %s (%s)",
878 inpkt.data[14] >> 4, from->name, from->hostname);
883 receive_packet(from, &inpkt);
888 send a packet to the given vpn ip.
890 void send_packet(node_t *n, vpn_packet_t *packet) {
895 memcpy(packet->data, mymac.x, ETH_ALEN);
897 n->out_bytes += packet->len;
898 devops.write(packet);
902 logger(DEBUG_TRAFFIC, LOG_ERR, "Sending packet of %d bytes to %s (%s)",
903 packet->len, n->name, n->hostname);
905 if(!n->status.reachable) {
906 logger(DEBUG_TRAFFIC, LOG_INFO, "Node %s (%s) is not reachable",
907 n->name, n->hostname);
912 n->out_bytes += packet->len;
914 if(n->status.sptps) {
915 send_sptps_packet(n, packet);
919 via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
922 logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet to %s via %s (%s)",
923 n->name, via->name, n->via->hostname);
925 if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) {
926 if(!send_tcppacket(via->connection, packet))
927 terminate_connection(via->connection, true);
929 send_udppacket(via, packet);
932 /* Broadcast a packet using the minimum spanning tree */
934 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
935 // Always give ourself a copy of the packet.
937 send_packet(myself, packet);
939 // In TunnelServer mode, do not forward broadcast packets.
940 // The MST might not be valid and create loops.
941 if(tunnelserver || broadcast_mode == BMODE_NONE)
944 logger(DEBUG_TRAFFIC, LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
945 packet->len, from->name, from->hostname);
947 switch(broadcast_mode) {
948 // In MST mode, broadcast packets travel via the Minimum Spanning Tree.
949 // This guarantees all nodes receive the broadcast packet, and
950 // usually distributes the sending of broadcast packets over all nodes.
952 for list_each(connection_t, c, connection_list)
953 if(c->status.active && c->status.mst && c != from->nexthop->connection)
954 send_packet(c->node, packet);
957 // In direct mode, we send copies to each node we know of.
958 // However, this only reaches nodes that can be reached in a single hop.
959 // We don't have enough information to forward broadcast packets in this case.
964 for splay_each(node_t, n, node_tree)
965 if(n->status.reachable && n != myself && ((n->via == myself && n->nexthop == n) || n->via == n))
966 send_packet(n, packet);
974 static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
977 static time_t last_hard_try = 0;
979 for splay_each(edge_t, e, edge_weight_tree) {
980 if(!e->to->status.reachable || e->to == myself)
983 if(sockaddrcmp_noport(from, &e->address)) {
984 if(last_hard_try == now.tv_sec)
989 if(!try_mac(e->to, pkt))
997 last_hard_try = now.tv_sec;
999 last_hard_try = now.tv_sec;
1003 void handle_incoming_vpn_data(void *data, int flags) {
1004 listen_socket_t *ls = data;
1007 sockaddr_t from = {{0}};
1008 socklen_t fromlen = sizeof from;
1012 len = recvfrom(ls->udp.fd, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
1014 if(len <= 0 || len > MAXSIZE) {
1015 if(!sockwouldblock(sockerrno))
1016 logger(DEBUG_ALWAYS, LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
1022 sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
1024 n = lookup_node_udp(&from);
1027 n = try_harder(&from, &pkt);
1029 update_node_udp(n, &from);
1030 else if(debug_level >= DEBUG_PROTOCOL) {
1031 hostname = sockaddr2hostname(&from);
1032 logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
1040 n->sock = ls - listen_socket;
1042 receive_udppacket(n, &pkt);
1045 void handle_device_data(void *data, int flags) {
1046 vpn_packet_t packet;
1048 packet.priority = 0;
1050 if(devops.read(&packet)) {
1051 myself->in_packets++;
1052 myself->in_bytes += packet.len;
1053 route(myself, &packet);