X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=5c69671ad30a7d55602569defe55db43eb970f9d;hp=a6f6e4636a5b7043b99070404ba301ac839f1420;hb=43a6e786648fb666a9b7be8f05c8a173031c9110;hpb=b0a4f7b5551cae6fb5af2eb4bcb0dfb3443f7d89 diff --git a/src/route.c b/src/route.c index a6f6e463..5c69671a 100644 --- a/src/route.c +++ b/src/route.c @@ -1,7 +1,7 @@ /* route.c -- routing - Copyright (C) 2000-2003 Ivo Timmermans , - 2000-2003 Guus Sliepen + Copyright (C) 2000-2005 Ivo Timmermans, + 2000-2009 Guus Sliepen 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 @@ -13,37 +13,15 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - - $Id: route.c,v 1.1.2.60 2003/07/18 12:16:24 guus Exp $ + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "system.h" -#ifdef HAVE_NET_ETHERNET_H -#include -#endif -#ifdef HAVE_NET_IF_ARP_H -#include -#endif -#ifdef HAVE_NETINET_IP_ICMP_H -#include -#endif -#ifdef HAVE_NETINET_IP6_H -#include -#endif -#ifdef HAVE_NETINET_ICMP6_H -#include -#endif -#ifdef HAVE_NETINET_IF_ETHER_H -#include -#endif - #include "avl_tree.h" #include "connection.h" -#include "device.h" #include "ethernet.h" #include "ipv4.h" #include "ipv6.h" @@ -54,34 +32,26 @@ #include "subnet.h" #include "utils.h" -/* Missing definitions */ - -#ifndef ETHER_ADDR_LEN -#define ETHER_ADDR_LEN 6 -#endif - -#ifndef ICMP_DEST_UNREACH -#define ICMP_DEST_UNREACH 3 -#endif - -#ifndef ICMP_NET_UNKNOWN -#define ICMP_NET_UNKNOWN 6 -#endif - -#ifndef ICMP_NET_UNREACH -#define ICMP_NET_UNREACH 0 -#endif - -int routing_mode = RMODE_ROUTER; -int priorityinheritance = 0; +rmode_t routing_mode = RMODE_ROUTER; +bool priorityinheritance = false; int macexpire = 600; -int overwrite_mac = 0; +bool overwrite_mac = false; mac_t mymac = {{0xFE, 0xFD, 0, 0, 0, 0}}; +/* Sizes of various headers */ + +static const size_t ether_size = sizeof(struct ether_header); +static const size_t arp_size = sizeof(struct ether_arp); +static const size_t ip_size = sizeof(struct ip); +static const size_t icmp_size = sizeof(struct icmp) - sizeof(struct ip); +static const size_t ip6_size = sizeof(struct ip6_hdr); +static const size_t icmp6_size = sizeof(struct icmp6_hdr); +static const size_t ns_size = sizeof(struct nd_neighbor_solicit); +static const size_t opt_size = sizeof(struct nd_opt_hdr); + /* RFC 1071 */ -static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) -{ +static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) { uint16_t *p = data; uint32_t checksum = prevsum ^ 0xFFFF; @@ -91,7 +61,7 @@ static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) } if(len) - checksum += *(unsigned char *)p; + checksum += *(uint8_t *)p; while(checksum >> 16) checksum = (checksum & 0xFFFF) + (checksum >> 16); @@ -99,69 +69,87 @@ static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) return ~checksum; } -static int ratelimit(void) { +static bool ratelimit(int frequency) { static time_t lasttime = 0; + static int count = 0; - if(lasttime == now) - return 1; + if(lasttime == now) { + if(++count > frequency) + return true; + } else { + lasttime = now; + count = 0; + } - lasttime = now; - return 0; + return false; +} + +static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) { + if(packet->len < length) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Got too short packet from %s (%s)", source->name, source->hostname); + return false; + } else + return true; +} + +static void swap_mac_addresses(vpn_packet_t *packet) { + mac_t tmp; + memcpy(&tmp, &packet->data[0], sizeof tmp); + memcpy(&packet->data[0], &packet->data[6], sizeof tmp); + memcpy(&packet->data[6], &tmp, sizeof tmp); } -static void learn_mac(mac_t *address) -{ +static void learn_mac(mac_t *address) { subnet_t *subnet; avl_node_t *node; connection_t *c; - cp(); - subnet = lookup_subnet_mac(address); /* If we don't know this MAC address yet, store it */ - if(!subnet || subnet->owner != myself) { - ifdebug(TRAFFIC) logger(LOG_INFO, _("Learned new MAC address %hx:%hx:%hx:%hx:%hx:%hx"), + if(!subnet) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Learned new MAC address %hx:%hx:%hx:%hx:%hx:%hx", address->x[0], address->x[1], address->x[2], address->x[3], address->x[4], address->x[5]); subnet = new_subnet(); subnet->type = SUBNET_MAC; - memcpy(&subnet->net.mac.address, address, sizeof(mac_t)); + subnet->expires = now + macexpire; + subnet->net.mac.address = *address; + subnet->weight = 10; subnet_add(myself, subnet); /* And tell all other tinc daemons it's our MAC */ for(node = connection_tree->head; node; node = node->next) { - c = (connection_t *) node->data; + c = node->data; if(c->status.active) send_add_subnet(c, subnet); } } - subnet->net.mac.lastseen = now; + if(subnet->expires) + subnet->expires = now + macexpire; } -void age_mac(void) -{ +void age_subnets(void) { subnet_t *s; connection_t *c; avl_node_t *node, *next, *node2; - cp(); - for(node = myself->subnet_tree->head; node; node = next) { next = node->next; - s = (subnet_t *) node->data; - if(s->type == SUBNET_MAC && s->net.mac.lastseen && s->net.mac.lastseen + macexpire < now) { - ifdebug(TRAFFIC) logger(LOG_INFO, _("MAC address %hx:%hx:%hx:%hx:%hx:%hx expired"), - s->net.mac.address.x[0], s->net.mac.address.x[1], - s->net.mac.address.x[2], s->net.mac.address.x[3], - s->net.mac.address.x[4], s->net.mac.address.x[5]); + s = node->data; + if(s->expires && s->expires < now) { + ifdebug(TRAFFIC) { + char netstr[MAXNETSTR]; + if(net2str(netstr, sizeof netstr, s)) + logger(LOG_INFO, "Subnet %s expired", netstr); + } for(node2 = connection_tree->head; node2; node2 = node2->next) { - c = (connection_t *) node2->data; + c = node2->data; if(c->status.active) send_del_subnet(c, s); } @@ -171,119 +159,196 @@ void age_mac(void) } } -static node_t *route_mac(vpn_packet_t *packet) -{ - subnet_t *subnet; - - cp(); - - /* Learn source address */ - - learn_mac((mac_t *)(&packet->data[6])); - - /* Lookup destination address */ - - subnet = lookup_subnet_mac((mac_t *)(&packet->data[0])); - - if(subnet) - return subnet->owner; - else - return NULL; -} - /* RFC 792 */ -static void route_ipv4_unreachable(vpn_packet_t *packet, uint8_t code) -{ - struct ip *hdr; - struct icmp *icmp; +static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code) { + struct ip ip = {0}; + struct icmp icmp = {0}; struct in_addr ip_src; struct in_addr ip_dst; uint32_t oldlen; - if(ratelimit()) + if(ratelimit(3)) return; - cp(); + /* Swap Ethernet source and destination addresses */ + + swap_mac_addresses(packet); + + /* Copy headers from packet into properly aligned structs on the stack */ - hdr = (struct ip *)(packet->data + 14); - icmp = (struct icmp *)(packet->data + 14 + 20); + memcpy(&ip, packet->data + ether_size, ip_size); /* Remember original source and destination */ - - memcpy(&ip_src, &hdr->ip_src, 4); - memcpy(&ip_dst, &hdr->ip_dst, 4); - oldlen = packet->len - 14; - if(oldlen >= IP_MSS - sizeof(*hdr) - sizeof(*icmp)) - oldlen = IP_MSS - sizeof(*hdr) - sizeof(*icmp); + ip_src = ip.ip_src; + ip_dst = ip.ip_dst; + + oldlen = packet->len - ether_size; + + if(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) + icmp.icmp_nextmtu = htons(packet->len - ether_size); + + if(oldlen >= IP_MSS - ip_size - icmp_size) + oldlen = IP_MSS - ip_size - icmp_size; /* Copy first part of original contents to ICMP message */ - memmove(&icmp->icmp_ip, hdr, oldlen); + memmove(packet->data + ether_size + ip_size + icmp_size, packet->data + ether_size, oldlen); /* Fill in IPv4 header */ - hdr->ip_v = 4; - hdr->ip_hl = sizeof(*hdr) / 4; - hdr->ip_tos = 0; - hdr->ip_len = htons(20 + 8 + oldlen); - hdr->ip_id = 0; - hdr->ip_off = 0; - hdr->ip_ttl = 255; - hdr->ip_p = IPPROTO_ICMP; - hdr->ip_sum = 0; - memcpy(&hdr->ip_src, &ip_dst, 4); - memcpy(&hdr->ip_dst, &ip_src, 4); - - hdr->ip_sum = inet_checksum(hdr, 20, ~0); + ip.ip_v = 4; + ip.ip_hl = ip_size / 4; + ip.ip_tos = 0; + ip.ip_len = htons(ip_size + icmp_size + oldlen); + ip.ip_id = 0; + ip.ip_off = 0; + ip.ip_ttl = 255; + ip.ip_p = IPPROTO_ICMP; + ip.ip_sum = 0; + ip.ip_src = ip_dst; + ip.ip_dst = ip_src; + + ip.ip_sum = inet_checksum(&ip, ip_size, ~0); /* Fill in ICMP header */ - icmp->icmp_type = ICMP_DEST_UNREACH; - icmp->icmp_code = code; - icmp->icmp_cksum = 0; + icmp.icmp_type = type; + icmp.icmp_code = code; + icmp.icmp_cksum = 0; - icmp->icmp_cksum = inet_checksum(icmp, 8 + oldlen, ~0); + icmp.icmp_cksum = inet_checksum(&icmp, icmp_size, ~0); + icmp.icmp_cksum = inet_checksum(packet->data + ether_size + ip_size + icmp_size, oldlen, icmp.icmp_cksum); + + /* Copy structs on stack back to packet */ + + memcpy(packet->data + ether_size, &ip, ip_size); + memcpy(packet->data + ether_size + ip_size, &icmp, icmp_size); + + packet->len = ether_size + ip_size + icmp_size + oldlen; + + send_packet(source, packet); +} + +/* RFC 791 */ + +static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet) { + struct ip ip; + vpn_packet_t fragment; + int len, maxlen, todo; + uint8_t *offset; + uint16_t ip_off, origf; - packet->len = 14 + 20 + 8 + oldlen; + memcpy(&ip, packet->data + ether_size, ip_size); + fragment.priority = packet->priority; + + if(ip.ip_hl != ip_size / 4) + return; - write_packet(packet); + todo = ntohs(ip.ip_len) - ip_size; + + if(ether_size + ip_size + todo != packet->len) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Length of packet (%d) doesn't match length in IPv4 header (%zd)", packet->len, ether_size + ip_size + todo); + return; + } + + ifdebug(TRAFFIC) logger(LOG_INFO, "Fragmenting packet of %d bytes to %s (%s)", packet->len, dest->name, dest->hostname); + + offset = packet->data + ether_size + ip_size; + maxlen = (dest->mtu - ether_size - ip_size) & ~0x7; + ip_off = ntohs(ip.ip_off); + origf = ip_off & ~IP_OFFMASK; + ip_off &= IP_OFFMASK; + + while(todo) { + len = todo > maxlen ? maxlen : todo; + memcpy(fragment.data + ether_size + ip_size, offset, len); + todo -= len; + offset += len; + + ip.ip_len = htons(ip_size + len); + ip.ip_off = htons(ip_off | origf | (todo ? IP_MF : 0)); + ip.ip_sum = 0; + ip.ip_sum = inet_checksum(&ip, ip_size, ~0); + memcpy(fragment.data, packet->data, ether_size); + memcpy(fragment.data + ether_size, &ip, ip_size); + fragment.len = ether_size + ip_size + len; + + send_packet(dest, &fragment); + + ip_off += len / 8; + } } -static node_t *route_ipv4(vpn_packet_t *packet) -{ +static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) { subnet_t *subnet; + node_t *via; + ipv4_t dest; - cp(); + memcpy(&dest, &packet->data[30], sizeof dest); + subnet = lookup_subnet_ipv4(&dest); + + if(!subnet) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet from %s (%s): unknown IPv4 destination address %d.%d.%d.%d", + source->name, source->hostname, + dest.x[0], + dest.x[1], + dest.x[2], + dest.x[3]); + + route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN); + return; + } + + if(subnet->owner == source) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname); + return; + } + + if(!subnet->owner->status.reachable) + route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNREACH); if(priorityinheritance) packet->priority = packet->data[15]; - subnet = lookup_subnet_ipv4((ipv4_t *) & packet->data[30]); - - if(!subnet) { - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown IPv4 destination address %d.%d.%d.%d"), - packet->data[30], packet->data[31], packet->data[32], - packet->data[33]); + via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via; + + if(via && packet->len > via->mtu && via != myself) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu); + if(packet->data[20] & 0x40) { + packet->len = via->mtu; + route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED); + } else { + fragment_ipv4_packet(via, packet); + } - route_ipv4_unreachable(packet, ICMP_NET_UNKNOWN); - return NULL; + return; } - - if(!subnet->owner->status.reachable) - route_ipv4_unreachable(packet, ICMP_NET_UNREACH); - return subnet->owner; + send_packet(subnet->owner, packet); +} + +static void route_ipv4(node_t *source, vpn_packet_t *packet) { + if(!checklength(source, packet, ether_size + ip_size)) + return; + + if(((packet->data[30] & 0xf0) == 0xe0) || ( + packet->data[30] == 255 && + packet->data[31] == 255 && + packet->data[32] == 255 && + packet->data[33] == 255)) + broadcast_packet(source, packet); + else + route_ipv4_unicast(source, packet); } /* RFC 2463 */ -static void route_ipv6_unreachable(vpn_packet_t *packet, uint8_t code) -{ - struct ip6_hdr *hdr; - struct icmp6_hdr *icmp; +static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code) { + struct ip6_hdr ip6; + struct icmp6_hdr icmp6 = {0}; uint16_t checksum; struct { @@ -293,97 +358,125 @@ static void route_ipv6_unreachable(vpn_packet_t *packet, uint8_t code) uint32_t next; } pseudo; - if(ratelimit()) + if(ratelimit(3)) return; - cp(); + /* Swap Ethernet source and destination addresses */ + + swap_mac_addresses(packet); + + /* Copy headers from packet to structs on the stack */ - hdr = (struct ip6_hdr *)(packet->data + 14); - icmp = (struct icmp6_hdr *)(packet->data + 14 + sizeof(*hdr)); + memcpy(&ip6, packet->data + ether_size, ip6_size); /* Remember original source and destination */ - - memcpy(&pseudo.ip6_src, &hdr->ip6_dst, 16); - memcpy(&pseudo.ip6_dst, &hdr->ip6_src, 16); - pseudo.length = ntohs(hdr->ip6_plen) + sizeof(*hdr); - if(pseudo.length >= IP_MSS - sizeof(*hdr) - sizeof(*icmp)) - pseudo.length = IP_MSS - sizeof(*hdr) - sizeof(*icmp); + pseudo.ip6_src = ip6.ip6_dst; + pseudo.ip6_dst = ip6.ip6_src; + + pseudo.length = packet->len - ether_size; + + if(type == ICMP6_PACKET_TOO_BIG) + icmp6.icmp6_mtu = htonl(pseudo.length); + + if(pseudo.length >= IP_MSS - ip6_size - icmp6_size) + pseudo.length = IP_MSS - ip6_size - icmp6_size; /* Copy first part of original contents to ICMP message */ - memmove(((char *)icmp) + sizeof(*icmp), hdr, pseudo.length); + memmove(packet->data + ether_size + ip6_size + icmp6_size, packet->data + ether_size, pseudo.length); /* Fill in IPv6 header */ - hdr->ip6_flow = htonl(0x60000000UL); - hdr->ip6_plen = htons(sizeof(*icmp) + pseudo.length); - hdr->ip6_nxt = IPPROTO_ICMPV6; - hdr->ip6_hlim = 255; - memcpy(&hdr->ip6_dst, &pseudo.ip6_dst, 16); - memcpy(&hdr->ip6_src, &pseudo.ip6_src, 16); + ip6.ip6_flow = htonl(0x60000000UL); + ip6.ip6_plen = htons(icmp6_size + pseudo.length); + ip6.ip6_nxt = IPPROTO_ICMPV6; + ip6.ip6_hlim = 255; + ip6.ip6_src = pseudo.ip6_src; + ip6.ip6_dst = pseudo.ip6_dst; /* Fill in ICMP header */ - icmp->icmp6_type = ICMP6_DST_UNREACH; - icmp->icmp6_code = code; - icmp->icmp6_cksum = 0; + icmp6.icmp6_type = type; + icmp6.icmp6_code = code; + icmp6.icmp6_cksum = 0; /* Create pseudo header */ - pseudo.length = htonl(sizeof(*icmp) + pseudo.length); + pseudo.length = htonl(icmp6_size + pseudo.length); pseudo.next = htonl(IPPROTO_ICMPV6); /* Generate checksum */ checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); - checksum = inet_checksum(icmp, ntohl(pseudo.length), checksum); + checksum = inet_checksum(&icmp6, icmp6_size, checksum); + checksum = inet_checksum(packet->data + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum); + + icmp6.icmp6_cksum = checksum; - icmp->icmp6_cksum = checksum; + /* Copy structs on stack back to packet */ + + memcpy(packet->data + ether_size, &ip6, ip6_size); + memcpy(packet->data + ether_size + ip6_size, &icmp6, icmp6_size); - packet->len = 14 + sizeof(*hdr) + ntohl(pseudo.length); + packet->len = ether_size + ip6_size + ntohl(pseudo.length); - write_packet(packet); + send_packet(source, packet); } -static node_t *route_ipv6(vpn_packet_t *packet) -{ +static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) { subnet_t *subnet; + node_t *via; + ipv6_t dest; - cp(); - - subnet = lookup_subnet_ipv6((ipv6_t *) & packet->data[38]); + memcpy(&dest, &packet->data[38], sizeof dest); + subnet = lookup_subnet_ipv6(&dest); if(!subnet) { - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"), - ntohs(*(uint16_t *) & packet->data[38]), - ntohs(*(uint16_t *) & packet->data[40]), - ntohs(*(uint16_t *) & packet->data[42]), - ntohs(*(uint16_t *) & packet->data[44]), - ntohs(*(uint16_t *) & packet->data[46]), - ntohs(*(uint16_t *) & packet->data[48]), - ntohs(*(uint16_t *) & packet->data[50]), - ntohs(*(uint16_t *) & packet->data[52])); - route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_ADDR); - - return NULL; + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet from %s (%s): unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx", + source->name, source->hostname, + ntohs(dest.x[0]), + ntohs(dest.x[1]), + ntohs(dest.x[2]), + ntohs(dest.x[3]), + ntohs(dest.x[4]), + ntohs(dest.x[5]), + ntohs(dest.x[6]), + ntohs(dest.x[7])); + + route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR); + return; + } + + if(subnet->owner == source) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname); + return; } if(!subnet->owner->status.reachable) - route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_NOROUTE); + route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE); + + via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via; - return subnet->owner; + if(via && packet->len > via->mtu && via != myself) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu); + packet->len = via->mtu; + route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0); + return; + } + + send_packet(subnet->owner, packet); } /* RFC 2461 */ -static void route_neighborsol(vpn_packet_t *packet) -{ - struct ip6_hdr *hdr; - struct nd_neighbor_solicit *ns; - struct nd_opt_hdr *opt; +static void route_neighborsol(node_t *source, vpn_packet_t *packet) { + struct ip6_hdr ip6; + struct nd_neighbor_solicit ns; + struct nd_opt_hdr opt; subnet_t *subnet; uint16_t checksum; + bool has_opt; struct { struct in6_addr ip6_src; /* source address */ @@ -392,56 +485,74 @@ static void route_neighborsol(vpn_packet_t *packet) uint32_t next; } pseudo; - cp(); + if(!checklength(source, packet, ether_size + ip6_size + ns_size)) + return; + + has_opt = packet->len >= ether_size + ip6_size + ns_size + opt_size + ETH_ALEN; + + if(source != myself) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Got neighbor solicitation request from %s (%s) while in router mode!", source->name, source->hostname); + return; + } + + /* Copy headers from packet to structs on the stack */ - hdr = (struct ip6_hdr *)(packet->data + 14); - ns = (struct nd_neighbor_solicit *)(packet->data + 14 + sizeof(*hdr)); - opt = (struct nd_opt_hdr *)(packet->data + 14 + sizeof(*hdr) + sizeof(*ns)); + memcpy(&ip6, packet->data + ether_size, ip6_size); + memcpy(&ns, packet->data + ether_size + ip6_size, ns_size); + if(has_opt) + memcpy(&opt, packet->data + ether_size + ip6_size + ns_size, opt_size); /* First, snatch the source address from the neighbor solicitation packet */ if(overwrite_mac) - memcpy(mymac.x, packet->data + 6, 6); + memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN); /* Check if this is a valid neighbor solicitation request */ - if(ns->nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT || - opt->nd_opt_type != ND_OPT_SOURCE_LINKADDR) { - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type neighbor solicitation request")); + if(ns.nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT || + (has_opt && opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR)) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet: received unknown type neighbor solicitation request"); return; } /* Create pseudo header */ - memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16); - memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16); - pseudo.length = htonl(sizeof(*ns) + sizeof(*opt) + 6); + pseudo.ip6_src = ip6.ip6_src; + pseudo.ip6_dst = ip6.ip6_dst; + if(has_opt) + pseudo.length = htonl(ns_size + opt_size + ETH_ALEN); + else + pseudo.length = htonl(ns_size); pseudo.next = htonl(IPPROTO_ICMPV6); /* Generate checksum */ checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); - checksum = inet_checksum(ns, sizeof(*ns) + 8, checksum); + checksum = inet_checksum(&ns, ns_size, checksum); + if(has_opt) { + checksum = inet_checksum(&opt, opt_size, checksum); + checksum = inet_checksum(packet->data + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum); + } if(checksum) { - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request")); + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet: checksum error for neighbor solicitation request"); return; } /* Check if the IPv6 address exists on the VPN */ - subnet = lookup_subnet_ipv6((ipv6_t *) & ns->nd_ns_target); + subnet = lookup_subnet_ipv6((ipv6_t *) &ns.nd_ns_target); if(!subnet) { - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"), - ntohs(((uint16_t *) & ns->nd_ns_target)[0]), - ntohs(((uint16_t *) & ns->nd_ns_target)[1]), - ntohs(((uint16_t *) & ns->nd_ns_target)[2]), - ntohs(((uint16_t *) & ns->nd_ns_target)[3]), - ntohs(((uint16_t *) & ns->nd_ns_target)[4]), - ntohs(((uint16_t *) & ns->nd_ns_target)[5]), - ntohs(((uint16_t *) & ns->nd_ns_target)[6]), - ntohs(((uint16_t *) & ns->nd_ns_target)[7])); + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx", + ntohs(((uint16_t *) &ns.nd_ns_target)[0]), + ntohs(((uint16_t *) &ns.nd_ns_target)[1]), + ntohs(((uint16_t *) &ns.nd_ns_target)[2]), + ntohs(((uint16_t *) &ns.nd_ns_target)[3]), + ntohs(((uint16_t *) &ns.nd_ns_target)[4]), + ntohs(((uint16_t *) &ns.nd_ns_target)[5]), + ntohs(((uint16_t *) &ns.nd_ns_target)[6]), + ntohs(((uint16_t *) &ns.nd_ns_target)[7])); return; } @@ -453,77 +564,106 @@ static void route_neighborsol(vpn_packet_t *packet) /* Create neighbor advertation reply */ - memcpy(packet->data, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* copy destination address */ - packet->data[ETHER_ADDR_LEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */ + memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN); /* copy destination address */ + packet->data[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */ - memcpy(&hdr->ip6_dst, &hdr->ip6_src, 16); /* swap destination and source protocol address */ - memcpy(&hdr->ip6_src, &ns->nd_ns_target, 16); /* ... */ + ip6.ip6_dst = ip6.ip6_src; /* swap destination and source protocoll address */ + ip6.ip6_src = ns.nd_ns_target; - memcpy((char *) opt + sizeof(*opt), packet->data + ETHER_ADDR_LEN, 6); /* add fake source hard addr */ + if(has_opt) + memcpy(packet->data + ether_size + ip6_size + ns_size + opt_size, packet->data + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */ - ns->nd_ns_hdr.icmp6_cksum = 0; - ns->nd_ns_hdr.icmp6_type = ND_NEIGHBOR_ADVERT; - ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[0] = 0x40; /* Set solicited flag */ - ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[1] = - ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[2] = - ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[3] = 0; - opt->nd_opt_type = ND_OPT_TARGET_LINKADDR; + ns.nd_ns_cksum = 0; + ns.nd_ns_type = ND_NEIGHBOR_ADVERT; + ns.nd_ns_reserved = htonl(0x40000000UL); /* Set solicited flag */ + opt.nd_opt_type = ND_OPT_TARGET_LINKADDR; /* Create pseudo header */ - memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16); - memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16); - pseudo.length = htonl(sizeof(*ns) + sizeof(*opt) + 6); + pseudo.ip6_src = ip6.ip6_src; + pseudo.ip6_dst = ip6.ip6_dst; + if(has_opt) + pseudo.length = htonl(ns_size + opt_size + ETH_ALEN); + else + pseudo.length = htonl(ns_size); pseudo.next = htonl(IPPROTO_ICMPV6); /* Generate checksum */ checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); - checksum = inet_checksum(ns, sizeof(*ns) + 8, checksum); + checksum = inet_checksum(&ns, ns_size, checksum); + if(has_opt) { + checksum = inet_checksum(&opt, opt_size, checksum); + checksum = inet_checksum(packet->data + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum); + } + + ns.nd_ns_hdr.icmp6_cksum = checksum; + + /* Copy structs on stack back to packet */ + + memcpy(packet->data + ether_size, &ip6, ip6_size); + memcpy(packet->data + ether_size + ip6_size, &ns, ns_size); + if(has_opt) + memcpy(packet->data + ether_size + ip6_size + ns_size, &opt, opt_size); - ns->nd_ns_hdr.icmp6_cksum = checksum; + send_packet(source, packet); +} + +static void route_ipv6(node_t *source, vpn_packet_t *packet) { + if(!checklength(source, packet, ether_size + ip6_size)) + return; - write_packet(packet); + if(packet->data[20] == IPPROTO_ICMPV6 && checklength(source, packet, ether_size + ip6_size + icmp6_size) && packet->data[54] == ND_NEIGHBOR_SOLICIT) { + route_neighborsol(source, packet); + return; + } + + if(packet->data[38] == 255) + broadcast_packet(source, packet); + else + route_ipv6_unicast(source, packet); } /* RFC 826 */ -static void route_arp(vpn_packet_t *packet) -{ - struct ether_arp *arp; +static void route_arp(node_t *source, vpn_packet_t *packet) { + struct ether_arp arp; subnet_t *subnet; - uint8_t ipbuf[4]; + struct in_addr addr; + + if(!checklength(source, packet, ether_size + arp_size)) + return; - cp(); + if(source != myself) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Got ARP request from %s (%s) while in router mode!", source->name, source->hostname); + return; + } /* First, snatch the source address from the ARP packet */ if(overwrite_mac) - memcpy(mymac.x, packet->data + 6, 6); + memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN); - /* This routine generates replies to ARP requests. - You don't need to set NOARP flag on the interface anymore (which is broken on FreeBSD). - Most of the code here is taken from choparp.c by Takamichi Tateoka (tree@mma.club.uec.ac.jp) - */ + /* Copy headers from packet to structs on the stack */ - arp = (struct ether_arp *)(packet->data + 14); + memcpy(&arp, packet->data + ether_size, arp_size); /* Check if this is a valid ARP request */ - if(ntohs(arp->arp_hrd) != ARPHRD_ETHER || ntohs(arp->arp_pro) != ETHERTYPE_IP || - arp->arp_hln != ETHER_ADDR_LEN || arp->arp_pln != 4 || ntohs(arp->arp_op) != ARPOP_REQUEST) { - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type ARP request")); + if(ntohs(arp.arp_hrd) != ARPHRD_ETHER || ntohs(arp.arp_pro) != ETH_P_IP || + arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof(addr) || ntohs(arp.arp_op) != ARPOP_REQUEST) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet: received unknown type ARP request"); return; } /* Check if the IPv4 address exists on the VPN */ - subnet = lookup_subnet_ipv4((ipv4_t *) arp->arp_tpa); + subnet = lookup_subnet_ipv4((ipv4_t *) &arp.arp_tpa); if(!subnet) { - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: ARP request for unknown address %d.%d.%d.%d"), - arp->arp_tpa[0], arp->arp_tpa[1], arp->arp_tpa[2], - arp->arp_tpa[3]); + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet: ARP request for unknown address %d.%d.%d.%d", + arp.arp_tpa[0], arp.arp_tpa[1], arp.arp_tpa[2], + arp.arp_tpa[3]); return; } @@ -532,126 +672,111 @@ static void route_arp(vpn_packet_t *packet) if(subnet->owner == myself) return; /* silently ignore */ - memcpy(packet->data, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* copy destination address */ - packet->data[ETHER_ADDR_LEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */ + memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN); /* copy destination address */ + packet->data[ETH_ALEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */ + + memcpy(&addr, arp.arp_tpa, sizeof(addr)); /* save protocol addr */ + memcpy(arp.arp_tpa, arp.arp_spa, sizeof(addr)); /* swap destination and source protocol address */ + memcpy(arp.arp_spa, &addr, sizeof(addr)); /* ... */ - memcpy(ipbuf, arp->arp_tpa, 4); /* save protocol addr */ - memcpy(arp->arp_tpa, arp->arp_spa, 4); /* swap destination and source protocol address */ - memcpy(arp->arp_spa, ipbuf, 4); /* ... */ + memcpy(arp.arp_tha, arp.arp_sha, ETH_ALEN); /* set target hard/proto addr */ + memcpy(arp.arp_sha, packet->data + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */ + arp.arp_op = htons(ARPOP_REPLY); - memcpy(arp->arp_tha, arp->arp_sha, 10); /* set target hard/proto addr */ - memcpy(arp->arp_sha, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* add fake source hard addr */ - arp->arp_op = htons(ARPOP_REPLY); + /* Copy structs on stack back to packet */ - write_packet(packet); + memcpy(packet->data + ether_size, &arp, arp_size); + + send_packet(source, packet); } -void route_outgoing(vpn_packet_t *packet) -{ - uint16_t type; - node_t *n = NULL; +static void route_mac(node_t *source, vpn_packet_t *packet) { + subnet_t *subnet; + mac_t dest; - cp(); + /* Learn source address */ - /* FIXME: multicast? */ + if(source == myself) { + mac_t src; + memcpy(&src, &packet->data[6], sizeof src); + learn_mac(&src); + } - switch (routing_mode) { - case RMODE_ROUTER: - type = ntohs(*((uint16_t *)(&packet->data[12]))); - switch (type) { - case 0x0800: - n = route_ipv4(packet); - break; - - case 0x86DD: - if(packet->data[20] == IPPROTO_ICMPV6 && packet->data[54] == ND_NEIGHBOR_SOLICIT) { - route_neighborsol(packet); - return; - } - n = route_ipv6(packet); - break; - - case 0x0806: - route_arp(packet); - return; - - default: - ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown type %hx"), type); - return; - } - if(n) - send_packet(n, packet); - break; + /* Lookup destination address */ - case RMODE_SWITCH: - n = route_mac(packet); - if(n) - send_packet(n, packet); - else - broadcast_packet(myself, packet); - break; + memcpy(&dest, &packet->data[0], sizeof dest); + subnet = lookup_subnet_mac(&dest); - case RMODE_HUB: - broadcast_packet(myself, packet); - break; + if(!subnet) { + broadcast_packet(source, packet); + return; } + + if(subnet->owner == source) { + ifdebug(TRAFFIC) logger(LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname); + return; + } + + // Handle packets larger than PMTU + + node_t *via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via; + + if(via && packet->len > via->mtu && via != myself) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu); + uint16_t type = packet->data[12] << 8 | packet->data[13]; + if(type == ETH_P_IP) { + if(packet->data[20] & 0x40) { + packet->len = via->mtu; + route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED); + } else { + fragment_ipv4_packet(via, packet); + } + return; + } else if(type == ETH_P_IPV6) { + packet->len = via->mtu; + route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0); + return; + } + } + + send_packet(subnet->owner, packet); } -void route_incoming(node_t *source, vpn_packet_t *packet) -{ +void route(node_t *source, vpn_packet_t *packet) { + if(!checklength(source, packet, ether_size)) + return; + switch (routing_mode) { case RMODE_ROUTER: { - node_t *n = NULL; - uint16_t type; + uint16_t type = packet->data[12] << 8 | packet->data[13]; - type = ntohs(*((uint16_t *)(&packet->data[12]))); switch (type) { - case 0x0800: - n = route_ipv4(packet); + case ETH_P_ARP: + route_arp(source, packet); break; - case 0x86DD: - n = route_ipv6(packet); + case ETH_P_IP: + route_ipv4(source, packet); break; - default: - n = myself; + case ETH_P_IPV6: + route_ipv6(source, packet); break; - } - if(n) { - if(n == myself) { - if(overwrite_mac) - memcpy(packet->data, mymac.x, 6); - write_packet(packet); - } else - send_packet(n, packet); + default: + ifdebug(TRAFFIC) logger(LOG_WARNING, "Cannot route packet from %s (%s): unknown type %hx", source->name, source->hostname, type); + break; } } break; case RMODE_SWITCH: - { - subnet_t *subnet; - - subnet = lookup_subnet_mac((mac_t *)(&packet->data[0])); - - if(subnet) { - if(subnet->owner == myself) - write_packet(packet); - else - send_packet(subnet->owner, packet); - } else { - broadcast_packet(source, packet); - write_packet(packet); - } - } + route_mac(source, packet); break; case RMODE_HUB: - broadcast_packet(source, packet); /* Spread it on */ - write_packet(packet); + broadcast_packet(source, packet); break; } }