3 Copyright (C) 2000-2005 Ivo Timmermans,
4 2000-2013 Guus Sliepen <guus@tinc-vpn.org>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License along
17 with this program; if not, write to the Free Software Foundation, Inc.,
18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #include "connection.h"
24 #include "control_common.h"
36 rmode_t routing_mode = RMODE_ROUTER;
37 fmode_t forwarding_mode = FMODE_INTERNAL;
38 bmode_t broadcast_mode = BMODE_MST;
39 bool decrement_ttl = false;
40 bool directonly = false;
41 bool priorityinheritance = false;
43 bool overwrite_mac = false;
44 mac_t mymac = {{0xFE, 0xFD, 0, 0, 0, 0}};
47 /* Sizes of various headers */
49 static const size_t ether_size = sizeof(struct ether_header);
50 static const size_t arp_size = sizeof(struct ether_arp);
51 static const size_t ip_size = sizeof(struct ip);
52 static const size_t icmp_size = sizeof(struct icmp) - sizeof(struct ip);
53 static const size_t ip6_size = sizeof(struct ip6_hdr);
54 static const size_t icmp6_size = sizeof(struct icmp6_hdr);
55 static const size_t ns_size = sizeof(struct nd_neighbor_solicit);
56 static const size_t opt_size = sizeof(struct nd_opt_hdr);
59 #define MAX(a, b) ((a) > (b) ? (a) : (b))
62 static timeout_t age_subnets_timeout;
66 static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
68 uint32_t checksum = prevsum ^ 0xFFFF;
76 checksum += *(uint8_t *)p;
79 while(checksum >> 16) {
80 checksum = (checksum & 0xFFFF) + (checksum >> 16);
86 static bool ratelimit(int frequency) {
87 static time_t lasttime = 0;
90 if(lasttime == now.tv_sec) {
91 if(count >= frequency) {
95 lasttime = now.tv_sec;
103 static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
104 if(packet->len < length) {
105 logger(DEBUG_TRAFFIC, LOG_WARNING, "Got too short packet from %s (%s)", source->name, source->hostname);
112 static void swap_mac_addresses(vpn_packet_t *packet) {
114 memcpy(&tmp, &DATA(packet)[0], sizeof(tmp));
115 memcpy(&DATA(packet)[0], &DATA(packet)[6], sizeof(tmp));
116 memcpy(&DATA(packet)[6], &tmp, sizeof(tmp));
121 static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
123 struct icmp icmp = {0};
125 struct in_addr ip_src;
126 struct in_addr ip_dst;
133 /* Swap Ethernet source and destination addresses */
135 swap_mac_addresses(packet);
137 /* Copy headers from packet into properly aligned structs on the stack */
139 memcpy(&ip, DATA(packet) + ether_size, ip_size);
141 /* Remember original source and destination */
146 /* Try to reply with an IP address assigned to the local machine */
148 if(type == ICMP_TIME_EXCEEDED && code == ICMP_EXC_TTL) {
149 int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
152 struct sockaddr_in addr;
153 memset(&addr, 0, sizeof(addr));
154 addr.sin_family = AF_INET;
155 addr.sin_addr = ip.ip_src;
157 if(!connect(sockfd, (const struct sockaddr *) &addr, sizeof(addr))) {
158 memset(&addr, 0, sizeof(addr));
159 addr.sin_family = AF_INET;
160 socklen_t addrlen = sizeof(addr);
162 if(!getsockname(sockfd, (struct sockaddr *) &addr, &addrlen) && addrlen <= sizeof(addr)) {
163 ip_dst = addr.sin_addr;
171 oldlen = packet->len - ether_size;
173 if(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
174 icmp.icmp_nextmtu = htons(packet->len - ether_size);
177 if(oldlen >= IP_MSS - ip_size - icmp_size) {
178 oldlen = IP_MSS - ip_size - icmp_size;
181 /* Copy first part of original contents to ICMP message */
183 memmove(DATA(packet) + ether_size + ip_size + icmp_size, DATA(packet) + ether_size, oldlen);
185 /* Fill in IPv4 header */
188 ip.ip_hl = ip_size / 4;
190 ip.ip_len = htons(ip_size + icmp_size + oldlen);
194 ip.ip_p = IPPROTO_ICMP;
199 ip.ip_sum = inet_checksum(&ip, ip_size, ~0);
201 /* Fill in ICMP header */
203 icmp.icmp_type = type;
204 icmp.icmp_code = code;
207 icmp.icmp_cksum = inet_checksum(&icmp, icmp_size, ~0);
208 icmp.icmp_cksum = inet_checksum(DATA(packet) + ether_size + ip_size + icmp_size, oldlen, icmp.icmp_cksum);
210 /* Copy structs on stack back to packet */
212 memcpy(DATA(packet) + ether_size, &ip, ip_size);
213 memcpy(DATA(packet) + ether_size + ip_size, &icmp, icmp_size);
215 packet->len = ether_size + ip_size + icmp_size + oldlen;
217 send_packet(source, packet);
222 static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
224 struct icmp6_hdr icmp6 = {0};
228 struct in6_addr ip6_src; /* source address */
229 struct in6_addr ip6_dst; /* destination address */
238 /* Swap Ethernet source and destination addresses */
240 swap_mac_addresses(packet);
242 /* Copy headers from packet to structs on the stack */
244 memcpy(&ip6, DATA(packet) + ether_size, ip6_size);
246 /* Remember original source and destination */
248 pseudo.ip6_src = ip6.ip6_dst;
249 pseudo.ip6_dst = ip6.ip6_src;
251 /* Try to reply with an IP address assigned to the local machine */
253 if(type == ICMP6_TIME_EXCEEDED && code == ICMP6_TIME_EXCEED_TRANSIT) {
254 int sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
257 struct sockaddr_in6 addr;
258 memset(&addr, 0, sizeof(addr));
259 addr.sin6_family = AF_INET6;
260 addr.sin6_addr = ip6.ip6_src;
262 if(!connect(sockfd, (const struct sockaddr *) &addr, sizeof(addr))) {
263 memset(&addr, 0, sizeof(addr));
264 addr.sin6_family = AF_INET6;
265 socklen_t addrlen = sizeof(addr);
267 if(!getsockname(sockfd, (struct sockaddr *) &addr, &addrlen) && addrlen <= sizeof(addr)) {
268 pseudo.ip6_src = addr.sin6_addr;
276 pseudo.length = packet->len - ether_size;
278 if(type == ICMP6_PACKET_TOO_BIG) {
279 icmp6.icmp6_mtu = htonl(pseudo.length);
282 if(pseudo.length >= IP_MSS - ip6_size - icmp6_size) {
283 pseudo.length = IP_MSS - ip6_size - icmp6_size;
286 /* Copy first part of original contents to ICMP message */
288 memmove(DATA(packet) + ether_size + ip6_size + icmp6_size, DATA(packet) + ether_size, pseudo.length);
290 /* Fill in IPv6 header */
292 ip6.ip6_flow = htonl(0x60000000UL);
293 ip6.ip6_plen = htons(icmp6_size + pseudo.length);
294 ip6.ip6_nxt = IPPROTO_ICMPV6;
296 ip6.ip6_src = pseudo.ip6_src;
297 ip6.ip6_dst = pseudo.ip6_dst;
299 /* Fill in ICMP header */
301 icmp6.icmp6_type = type;
302 icmp6.icmp6_code = code;
303 icmp6.icmp6_cksum = 0;
305 /* Create pseudo header */
307 pseudo.length = htonl(icmp6_size + pseudo.length);
308 pseudo.next = htonl(IPPROTO_ICMPV6);
310 /* Generate checksum */
312 checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
313 checksum = inet_checksum(&icmp6, icmp6_size, checksum);
314 checksum = inet_checksum(DATA(packet) + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
316 icmp6.icmp6_cksum = checksum;
318 /* Copy structs on stack back to packet */
320 memcpy(DATA(packet) + ether_size, &ip6, ip6_size);
321 memcpy(DATA(packet) + ether_size + ip6_size, &icmp6, icmp6_size);
323 packet->len = ether_size + ip6_size + ntohl(pseudo.length);
325 send_packet(source, packet);
328 static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
329 uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
330 length_t ethlen = ether_size;
332 if(type == ETH_P_8021Q) {
333 type = DATA(packet)[16] << 8 | DATA(packet)[17];
339 if(!checklength(source, packet, ethlen + ip_size)) {
343 if(DATA(packet)[ethlen + 8] <= 1) {
344 if(DATA(packet)[ethlen + 11] != IPPROTO_ICMP || DATA(packet)[ethlen + 32] != ICMP_TIME_EXCEEDED) {
345 route_ipv4_unreachable(source, packet, ethlen, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
351 uint16_t old = DATA(packet)[ethlen + 8] << 8 | DATA(packet)[ethlen + 9];
352 DATA(packet)[ethlen + 8]--;
353 uint16_t new = DATA(packet)[ethlen + 8] << 8 | DATA(packet)[ethlen + 9];
355 uint32_t checksum = DATA(packet)[ethlen + 10] << 8 | DATA(packet)[ethlen + 11];
356 checksum += old + (~new & 0xFFFF);
358 while(checksum >> 16) {
359 checksum = (checksum & 0xFFFF) + (checksum >> 16);
362 DATA(packet)[ethlen + 10] = checksum >> 8;
363 DATA(packet)[ethlen + 11] = checksum & 0xff;
368 if(!checklength(source, packet, ethlen + ip6_size)) {
372 if(DATA(packet)[ethlen + 7] <= 1) {
373 if(DATA(packet)[ethlen + 6] != IPPROTO_ICMPV6 || DATA(packet)[ethlen + 40] != ICMP6_TIME_EXCEEDED) {
374 route_ipv6_unreachable(source, packet, ethlen, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
380 DATA(packet)[ethlen + 7]--;
389 static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *packet) {
390 if(!source || !via || !(via->options & OPTION_CLAMP_MSS)) {
394 uint16_t mtu = source->mtu;
396 if(via != myself && via->mtu < mtu) {
400 /* Find TCP header */
401 int start = ether_size;
402 uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
404 if(type == ETH_P_8021Q) {
406 type = DATA(packet)[16] << 8 | DATA(packet)[17];
409 /* IP in IP (RFC 2003) packet */
410 if(type == ETH_P_IP && DATA(packet)[start + 9] == 4) {
414 if(packet->len <= start + 20) {
418 if(type == ETH_P_IP && DATA(packet)[start + 9] == 6) {
419 start += (DATA(packet)[start] & 0xf) * 4;
420 } else if(type == ETH_P_IPV6 && DATA(packet)[start + 6] == 6) {
426 if(packet->len <= start + 20) {
430 /* Use data offset field to calculate length of options field */
431 int len = ((DATA(packet)[start + 12] >> 4) - 5) * 4;
433 if(packet->len < start + 20 + len) {
437 /* Search for MSS option header */
438 for(int i = 0; i < len;) {
439 if(DATA(packet)[start + 20 + i] == 0) {
443 if(DATA(packet)[start + 20 + i] == 1) {
448 if(i > len - 2 || i > len - DATA(packet)[start + 21 + i]) {
452 if(DATA(packet)[start + 20 + i] != 2) {
453 if(DATA(packet)[start + 21 + i] < 2) {
457 i += DATA(packet)[start + 21 + i];
461 if(DATA(packet)[start + 21] != 4) {
466 uint16_t oldmss = DATA(packet)[start + 22 + i] << 8 | DATA(packet)[start + 23 + i];
467 uint16_t newmss = mtu - start - 20;
468 uint32_t csum = DATA(packet)[start + 16] << 8 | DATA(packet)[start + 17];
470 if(oldmss <= newmss) {
474 logger(DEBUG_TRAFFIC, LOG_INFO, "Clamping MSS of packet from %s to %s to %d", source->name, via->name, newmss);
476 /* Update the MSS value and the checksum */
477 DATA(packet)[start + 22 + i] = newmss >> 8;
478 DATA(packet)[start + 23 + i] = newmss & 0xff;
480 csum += oldmss ^ 0xffff;
482 csum = (csum & 0xffff) + (csum >> 16);
485 DATA(packet)[start + 16] = csum >> 8;
486 DATA(packet)[start + 17] = csum;
491 static void age_subnets(void *data) {
494 for splay_each(subnet_t, s, myself->subnet_tree) {
495 if(s->expires && s->expires < now.tv_sec) {
496 if(debug_level >= DEBUG_TRAFFIC) {
497 char netstr[MAXNETSTR];
499 if(net2str(netstr, sizeof(netstr), s)) {
500 logger(DEBUG_TRAFFIC, LOG_INFO, "Subnet %s expired", netstr);
504 for list_each(connection_t, c, connection_list)
506 send_del_subnet(c, s);
509 subnet_del(myself, s);
518 timeout_set(&age_subnets_timeout, &(struct timeval) {
523 static void learn_mac(mac_t *address) {
524 subnet_t *subnet = lookup_subnet_mac(myself, address);
526 /* If we don't know this MAC address yet, store it */
529 logger(DEBUG_TRAFFIC, LOG_INFO, "Learned new MAC address %x:%x:%x:%x:%x:%x",
530 address->x[0], address->x[1], address->x[2], address->x[3],
531 address->x[4], address->x[5]);
533 subnet = new_subnet();
534 subnet->type = SUBNET_MAC;
535 subnet->expires = now.tv_sec + macexpire;
536 subnet->net.mac.address = *address;
538 subnet_add(myself, subnet);
539 subnet_update(myself, subnet, true);
541 /* And tell all other tinc daemons it's our MAC */
543 for list_each(connection_t, c, connection_list)
545 send_add_subnet(c, subnet);
548 timeout_add(&age_subnets_timeout, age_subnets, NULL, &(struct timeval) {
552 if(subnet->expires) {
553 subnet->expires = now.tv_sec + macexpire;
558 static void route_broadcast(node_t *source, vpn_packet_t *packet) {
559 if(decrement_ttl && source != myself)
560 if(!do_decrement_ttl(source, packet)) {
564 broadcast_packet(source, packet);
569 static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet, length_t ether_size) {
571 vpn_packet_t fragment;
574 uint16_t ip_off, origf;
576 memcpy(&ip, DATA(packet) + ether_size, ip_size);
577 fragment.priority = packet->priority;
578 fragment.offset = DEFAULT_PACKET_OFFSET;
580 if(ip.ip_hl != ip_size / 4) {
584 todo = ntohs(ip.ip_len) - ip_size;
586 if(ether_size + ip_size + todo != packet->len) {
587 logger(DEBUG_TRAFFIC, LOG_WARNING, "Length of packet (%d) doesn't match length in IPv4 header (%d)", packet->len, (int)(ether_size + ip_size + todo));
591 logger(DEBUG_TRAFFIC, LOG_INFO, "Fragmenting packet of %d bytes to %s (%s)", packet->len, dest->name, dest->hostname);
593 offset = DATA(packet) + ether_size + ip_size;
594 maxlen = (dest->mtu - ether_size - ip_size) & ~0x7;
595 ip_off = ntohs(ip.ip_off);
596 origf = ip_off & ~IP_OFFMASK;
597 ip_off &= IP_OFFMASK;
600 int len = todo > maxlen ? maxlen : todo;
601 memcpy(DATA(&fragment) + ether_size + ip_size, offset, len);
605 ip.ip_len = htons(ip_size + len);
606 ip.ip_off = htons(ip_off | origf | (todo ? IP_MF : 0));
608 ip.ip_sum = inet_checksum(&ip, ip_size, ~0);
609 memcpy(DATA(&fragment), DATA(packet), ether_size);
610 memcpy(DATA(&fragment) + ether_size, &ip, ip_size);
611 fragment.len = ether_size + ip_size + len;
613 send_packet(dest, &fragment);
619 static void route_ipv4(node_t *source, vpn_packet_t *packet) {
620 if(!checklength(source, packet, ether_size + ip_size)) {
628 memcpy(&dest, &DATA(packet)[30], sizeof(dest));
629 subnet = lookup_subnet_ipv4(&dest);
632 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown IPv4 destination address %d.%d.%d.%d",
633 source->name, source->hostname,
639 route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
644 route_broadcast(source, packet);
648 if(subnet->owner == source) {
649 logger(DEBUG_TRAFFIC, LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname);
653 if(!subnet->owner->status.reachable) {
654 return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
657 if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
658 return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
661 if(decrement_ttl && source != myself && subnet->owner != myself)
662 if(!do_decrement_ttl(source, packet)) {
666 if(priorityinheritance) {
667 packet->priority = DATA(packet)[15];
670 via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
673 logger(DEBUG_TRAFFIC, LOG_ERR, "Routing loop for packet from %s (%s)!", source->name, source->hostname);
677 if(directonly && subnet->owner != via) {
678 return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
681 if(via && packet->len > MAX(via->mtu, 590) && via != myself) {
682 logger(DEBUG_TRAFFIC, LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
684 if(DATA(packet)[20] & 0x40) {
685 packet->len = MAX(via->mtu, 590);
686 route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
688 fragment_ipv4_packet(via, packet, ether_size);
694 clamp_mss(source, via, packet);
696 send_packet(subnet->owner, packet);
699 static void route_neighborsol(node_t *source, vpn_packet_t *packet);
701 static void route_ipv6(node_t *source, vpn_packet_t *packet) {
702 if(!checklength(source, packet, ether_size + ip6_size)) {
706 if(DATA(packet)[20] == IPPROTO_ICMPV6 && checklength(source, packet, ether_size + ip6_size + icmp6_size) && DATA(packet)[54] == ND_NEIGHBOR_SOLICIT) {
707 route_neighborsol(source, packet);
715 memcpy(&dest, &DATA(packet)[38], sizeof(dest));
716 subnet = lookup_subnet_ipv6(&dest);
719 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx",
720 source->name, source->hostname,
730 route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
735 route_broadcast(source, packet);
739 if(subnet->owner == source) {
740 logger(DEBUG_TRAFFIC, LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname);
744 if(!subnet->owner->status.reachable) {
745 return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
748 if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
749 return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
752 if(decrement_ttl && source != myself && subnet->owner != myself)
753 if(!do_decrement_ttl(source, packet)) {
757 if(priorityinheritance) {
758 packet->priority = ((DATA(packet)[14] & 0x0f) << 4) | (DATA(packet)[15] >> 4);
761 via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
764 logger(DEBUG_TRAFFIC, LOG_ERR, "Routing loop for packet from %s (%s)!", source->name, source->hostname);
768 if(directonly && subnet->owner != via) {
769 return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
772 if(via && packet->len > MAX(via->mtu, 1294) && via != myself) {
773 logger(DEBUG_TRAFFIC, LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
774 packet->len = MAX(via->mtu, 1294);
775 route_ipv6_unreachable(source, packet, ether_size, ICMP6_PACKET_TOO_BIG, 0);
779 clamp_mss(source, via, packet);
781 send_packet(subnet->owner, packet);
786 static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
788 struct nd_neighbor_solicit ns;
789 struct nd_opt_hdr opt;
795 struct in6_addr ip6_src;
796 struct in6_addr ip6_dst;
801 if(!checklength(source, packet, ether_size + ip6_size + ns_size)) {
805 has_opt = packet->len >= ether_size + ip6_size + ns_size + opt_size + ETH_ALEN;
807 if(source != myself) {
808 logger(DEBUG_TRAFFIC, LOG_WARNING, "Got neighbor solicitation request from %s (%s) while in router mode!", source->name, source->hostname);
812 /* Copy headers from packet to structs on the stack */
814 memcpy(&ip6, DATA(packet) + ether_size, ip6_size);
815 memcpy(&ns, DATA(packet) + ether_size + ip6_size, ns_size);
818 memcpy(&opt, DATA(packet) + ether_size + ip6_size + ns_size, opt_size);
821 /* First, snatch the source address from the neighbor solicitation packet */
824 memcpy(mymac.x, DATA(packet) + ETH_ALEN, ETH_ALEN);
827 /* Check if this is a valid neighbor solicitation request */
829 if(ns.nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT ||
830 (has_opt && opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR)) {
831 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: received unknown type neighbor solicitation request");
835 /* Create pseudo header */
837 pseudo.ip6_src = ip6.ip6_src;
838 pseudo.ip6_dst = ip6.ip6_dst;
841 pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
843 pseudo.length = htonl(ns_size);
846 pseudo.next = htonl(IPPROTO_ICMPV6);
848 /* Generate checksum */
850 checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
851 checksum = inet_checksum(&ns, ns_size, checksum);
854 checksum = inet_checksum(&opt, opt_size, checksum);
855 checksum = inet_checksum(DATA(packet) + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
859 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: checksum error for neighbor solicitation request");
863 /* Check if the IPv6 address exists on the VPN */
865 subnet = lookup_subnet_ipv6((ipv6_t *) &ns.nd_ns_target);
868 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx",
869 ntohs(((uint16_t *) &ns.nd_ns_target)[0]),
870 ntohs(((uint16_t *) &ns.nd_ns_target)[1]),
871 ntohs(((uint16_t *) &ns.nd_ns_target)[2]),
872 ntohs(((uint16_t *) &ns.nd_ns_target)[3]),
873 ntohs(((uint16_t *) &ns.nd_ns_target)[4]),
874 ntohs(((uint16_t *) &ns.nd_ns_target)[5]),
875 ntohs(((uint16_t *) &ns.nd_ns_target)[6]),
876 ntohs(((uint16_t *) &ns.nd_ns_target)[7]));
881 /* Check if it is for our own subnet */
883 if(subnet->owner == myself) {
884 return; /* silently ignore */
888 if(!do_decrement_ttl(source, packet)) {
892 /* Create neighbor advertation reply */
894 memcpy(DATA(packet), DATA(packet) + ETH_ALEN, ETH_ALEN); /* copy destination address */
895 DATA(packet)[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
897 ip6.ip6_dst = ip6.ip6_src; /* swap destination and source protocoll address */
898 ip6.ip6_src = ns.nd_ns_target;
901 memcpy(DATA(packet) + ether_size + ip6_size + ns_size + opt_size, DATA(packet) + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */
905 ns.nd_ns_type = ND_NEIGHBOR_ADVERT;
906 ns.nd_ns_reserved = htonl(0x40000000UL); /* Set solicited flag */
907 opt.nd_opt_type = ND_OPT_TARGET_LINKADDR;
909 /* Create pseudo header */
911 pseudo.ip6_src = ip6.ip6_src;
912 pseudo.ip6_dst = ip6.ip6_dst;
915 pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
917 pseudo.length = htonl(ns_size);
920 pseudo.next = htonl(IPPROTO_ICMPV6);
922 /* Generate checksum */
924 checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
925 checksum = inet_checksum(&ns, ns_size, checksum);
928 checksum = inet_checksum(&opt, opt_size, checksum);
929 checksum = inet_checksum(DATA(packet) + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
932 ns.nd_ns_hdr.icmp6_cksum = checksum;
934 /* Copy structs on stack back to packet */
936 memcpy(DATA(packet) + ether_size, &ip6, ip6_size);
937 memcpy(DATA(packet) + ether_size + ip6_size, &ns, ns_size);
940 memcpy(DATA(packet) + ether_size + ip6_size + ns_size, &opt, opt_size);
943 send_packet(source, packet);
948 static void route_arp(node_t *source, vpn_packet_t *packet) {
949 struct ether_arp arp;
953 if(!checklength(source, packet, ether_size + arp_size)) {
957 if(source != myself) {
958 logger(DEBUG_TRAFFIC, LOG_WARNING, "Got ARP request from %s (%s) while in router mode!", source->name, source->hostname);
962 /* First, snatch the source address from the ARP packet */
965 memcpy(mymac.x, DATA(packet) + ETH_ALEN, ETH_ALEN);
968 /* Copy headers from packet to structs on the stack */
970 memcpy(&arp, DATA(packet) + ether_size, arp_size);
972 /* Check if this is a valid ARP request */
974 if(ntohs(arp.arp_hrd) != ARPHRD_ETHER || ntohs(arp.arp_pro) != ETH_P_IP ||
975 arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof(addr) || ntohs(arp.arp_op) != ARPOP_REQUEST) {
976 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: received unknown type ARP request");
980 /* Check if the IPv4 address exists on the VPN */
982 subnet = lookup_subnet_ipv4((ipv4_t *) &arp.arp_tpa);
985 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: ARP request for unknown address %d.%d.%d.%d",
986 arp.arp_tpa[0], arp.arp_tpa[1], arp.arp_tpa[2],
991 /* Check if it is for our own subnet */
993 if(subnet->owner == myself) {
994 return; /* silently ignore */
998 if(!do_decrement_ttl(source, packet)) {
1002 memcpy(&addr, arp.arp_tpa, sizeof(addr)); /* save protocol addr */
1003 memcpy(arp.arp_tpa, arp.arp_spa, sizeof(addr)); /* swap destination and source protocol address */
1004 memcpy(arp.arp_spa, &addr, sizeof(addr)); /* ... */
1006 memcpy(arp.arp_tha, arp.arp_sha, ETH_ALEN); /* set target hard/proto addr */
1007 memcpy(arp.arp_sha, DATA(packet) + ETH_ALEN, ETH_ALEN); /* set source hard/proto addr */
1008 arp.arp_sha[ETH_ALEN - 1] ^= 0xFF; /* for consistency with route_packet() */
1009 arp.arp_op = htons(ARPOP_REPLY);
1011 /* Copy structs on stack back to packet */
1013 memcpy(DATA(packet) + ether_size, &arp, arp_size);
1015 send_packet(source, packet);
1018 static void route_mac(node_t *source, vpn_packet_t *packet) {
1022 /* Learn source address */
1024 if(source == myself) {
1026 memcpy(&src, &DATA(packet)[6], sizeof(src));
1030 /* Lookup destination address */
1032 memcpy(&dest, &DATA(packet)[0], sizeof(dest));
1033 subnet = lookup_subnet_mac(NULL, &dest);
1035 if(!subnet || !subnet->owner) {
1036 route_broadcast(source, packet);
1040 if(subnet->owner == source) {
1041 logger(DEBUG_TRAFFIC, LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname);
1045 if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
1049 if(decrement_ttl && source != myself && subnet->owner != myself)
1050 if(!do_decrement_ttl(source, packet)) {
1054 uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
1056 if(priorityinheritance) {
1057 if(type == ETH_P_IP && packet->len >= ether_size + ip_size) {
1058 packet->priority = DATA(packet)[15];
1059 } else if(type == ETH_P_IPV6 && packet->len >= ether_size + ip6_size) {
1060 packet->priority = ((DATA(packet)[14] & 0x0f) << 4) | (DATA(packet)[15] >> 4);
1064 // Handle packets larger than PMTU
1066 node_t *via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
1068 if(directonly && subnet->owner != via) {
1072 if(via && packet->len > via->mtu && via != myself) {
1073 logger(DEBUG_TRAFFIC, LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
1074 length_t ethlen = 14;
1076 if(type == ETH_P_8021Q) {
1077 type = DATA(packet)[16] << 8 | DATA(packet)[17];
1081 if(type == ETH_P_IP && packet->len > 576 + ethlen) {
1082 if(DATA(packet)[6 + ethlen] & 0x40) {
1083 packet->len = via->mtu;
1084 route_ipv4_unreachable(source, packet, ethlen, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
1086 fragment_ipv4_packet(via, packet, ethlen);
1090 } else if(type == ETH_P_IPV6 && packet->len > 1280 + ethlen) {
1091 packet->len = via->mtu;
1092 route_ipv6_unreachable(source, packet, ethlen, ICMP6_PACKET_TOO_BIG, 0);
1097 clamp_mss(source, via, packet);
1099 send_packet(subnet->owner, packet);
1102 static void send_pcap(vpn_packet_t *packet) {
1105 for list_each(connection_t, c, connection_list) {
1106 if(!c->status.pcap) {
1111 int len = packet->len;
1113 if(c->outmaclength && c->outmaclength < len) {
1114 len = c->outmaclength;
1117 if(send_request(c, "%d %d %d", CONTROL, REQ_PCAP, len)) {
1118 send_meta(c, (char *)DATA(packet), len);
1123 void route(node_t *source, vpn_packet_t *packet) {
1128 if(forwarding_mode == FMODE_KERNEL && source != myself) {
1129 send_packet(myself, packet);
1133 if(!checklength(source, packet, ether_size)) {
1137 uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
1139 switch(routing_mode) {
1143 route_arp(source, packet);
1147 route_ipv4(source, packet);
1151 route_ipv6(source, packet);
1155 logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown type %hx", source->name, source->hostname, type);
1162 route_mac(source, packet);
1166 route_broadcast(source, packet);