X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=e9e07f67263a2d39cbe468e06ae576ea516926f6;hp=0509b962ca4a8279b710662cd68c237e814652b6;hb=acbb9d6692614539260749c7b763eca5a6f81f07;hpb=698191fd2f512f3618e2d60592fcd57cd750b965 diff --git a/src/route.c b/src/route.c index 0509b962..e9e07f67 100644 --- a/src/route.c +++ b/src/route.c @@ -1,7 +1,7 @@ /* route.c -- routing - Copyright (C) 2000 Ivo Timmermans , - 2000 Guus Sliepen + Copyright (C) 2000-2003 Ivo Timmermans , + 2000-2003 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 @@ -17,96 +17,656 @@ along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - $Id: route.c,v 1.1.2.2 2000/11/04 22:57:33 guus Exp $ + $Id: route.c,v 1.1.2.66 2003/10/01 09:14:01 guus Exp $ */ -#include "config.h" +#include "system.h" -#include -#include +#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_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" +#include "logger.h" #include "net.h" -#include "connlist.h" +#include "protocol.h" +#include "route.h" +#include "subnet.h" +#include "utils.h" -#include "system.h" +rmode_t routing_mode = RMODE_ROUTER; +bool priorityinheritance = false; +int macexpire = 600; +bool overwrite_mac = false; +mac_t mymac = {{0xFE, 0xFD, 0, 0, 0, 0}}; -int routing_mode = 0; /* Will be used to determine if we route by MAC or by payload's protocol */ +/* RFC 1071 */ -conn_list_t *route_packet(vpn_packet_t *packet) +static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) { - unsigned short type; -cp - type = ntohs(*((unsigned short*)(&packet.data[12]))) - - if(routing_mode) - { - return route_mac(packet); - } - - switch(type) - { - case 0x0800: - return route_ipv4(packet); - case 0x86DD: - return route_ipv6(packet); -/* - case 0x8137: - return route_ipx(packet); - case 0x0806: - return route_arp(packet); -*/ - default: - if(debug_lvl >= DEBUG_TRAFFIC) - { - syslog(LOG_WARNING, _("Cannot route packet: unknown type %hx"), type); - } - return NULL; - } + uint16_t *p = data; + uint32_t checksum = prevsum ^ 0xFFFF; + + while(len >= 2) { + checksum += *p++; + len -= 2; + } + + if(len) + checksum += *(unsigned char *)p; + + while(checksum >> 16) + checksum = (checksum & 0xFFFF) + (checksum >> 16); + + return ~checksum; +} + +static bool ratelimit(void) { + static time_t lasttime = 0; + + if(lasttime == now) + return true; + + lasttime = now; + return false; +} + +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"), + 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_add(myself, subnet); + + /* And tell all other tinc daemons it's our MAC */ + + for(node = connection_tree->head; node; node = node->next) { + c = node->data; + if(c->status.active) + send_add_subnet(c, subnet); + } + } + + subnet->net.mac.lastseen = now; +} + +void age_mac(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 = 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]); + + for(node2 = connection_tree->head; node2; node2 = node2->next) { + c = node2->data; + if(c->status.active) + send_del_subnet(c, s); + } + + subnet_del(myself, s); + } + } +} + +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; + + struct in_addr ip_src; + struct in_addr ip_dst; + uint32_t oldlen; + + if(ratelimit()) + return; + + cp(); + + hdr = (struct ip *)(packet->data + 14); + icmp = (struct icmp *)(packet->data + 14 + 20); + + /* 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); + + /* Copy first part of original contents to ICMP message */ + + memmove(&icmp->icmp_ip, hdr, 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); + + /* Fill in ICMP header */ + + icmp->icmp_type = ICMP_DEST_UNREACH; + icmp->icmp_code = code; + icmp->icmp_cksum = 0; + + icmp->icmp_cksum = inet_checksum(icmp, 8 + oldlen, ~0); + + packet->len = 14 + 20 + 8 + oldlen; + + write_packet(packet); } -conn_list_t *route_mac(vpn_packet_t *packet) +static node_t *route_ipv4(vpn_packet_t *packet) { - conn_list_t *cl; -cp - cl = lookup_subnet_mac((mac_t *)(&packet.data[6])); - if(!cl) - if(debug_lvl >= DEBUG_TRAFFIC) - { - syslog(LOG_WARNING, _("Cannot route packet: unknown destination address %x:%x:%x:%x:%x:%x"), - packet.data[6], - packet.data[7], - packet.data[8], - packet.data[9], - packet.data[10], - packet.data[11]); - } -cp - return cl; + subnet_t *subnet; + + cp(); + + 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]); + + route_ipv4_unreachable(packet, ICMP_NET_UNKNOWN); + return NULL; + } + + if(!subnet->owner->status.reachable) + route_ipv4_unreachable(packet, ICMP_NET_UNREACH); + + return subnet->owner; } +/* RFC 2463 */ -conn_list_t *route_ipv4(vpn_packet_t *packet) +static void route_ipv6_unreachable(vpn_packet_t *packet, uint8_t code) { - ipv4_t dest; - conn_list_t *cl; -cp - dest = ntohl(*((unsigned long*)(&packet.data[30]); - - cl = lookup_subnet_ipv4(dest); - if(!cl) - if(debug_lvl >= DEBUG_TRAFFIC) - { - syslog(LOG_WARNING, _("Cannot route packet: unknown destination address %d.%d.%d.%d"), - packet.data[30], packet.data[31], packet.data[32], packet.data[33]); - } -cp - return cl; + struct ip6_hdr *hdr; + struct icmp6_hdr *icmp; + uint16_t checksum; + + struct { + struct in6_addr ip6_src; /* source address */ + struct in6_addr ip6_dst; /* destination address */ + uint32_t length; + uint32_t next; + } pseudo; + + if(ratelimit()) + return; + + cp(); + + hdr = (struct ip6_hdr *)(packet->data + 14); + icmp = (struct icmp6_hdr *)(packet->data + 14 + sizeof(*hdr)); + + /* 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); + + /* Copy first part of original contents to ICMP message */ + + memmove(((char *)icmp) + sizeof(*icmp), hdr, 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); + + /* Fill in ICMP header */ + + icmp->icmp6_type = ICMP6_DST_UNREACH; + icmp->icmp6_code = code; + icmp->icmp6_cksum = 0; + + /* Create pseudo header */ + + pseudo.length = htonl(sizeof(*icmp) + pseudo.length); + pseudo.next = htonl(IPPROTO_ICMPV6); + + /* Generate checksum */ + + checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); + checksum = inet_checksum(icmp, ntohl(pseudo.length), checksum); + + icmp->icmp6_cksum = checksum; + + packet->len = 14 + sizeof(*hdr) + ntohl(pseudo.length); + + write_packet(packet); +} + +static node_t *route_ipv6(vpn_packet_t *packet) +{ + subnet_t *subnet; + + cp(); + + subnet = lookup_subnet_ipv6((ipv6_t *) &packet->data[38]); + + 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; + } + + if(!subnet->owner->status.reachable) + route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_NOROUTE); + + return subnet->owner; } -conn_list_t *route_ipv6(vpn_packet_t *packet) +/* RFC 2461 */ + +static void route_neighborsol(vpn_packet_t *packet) { -cp - syslog(LOG_WARNING, _("Cannot route packet: IPv6 routing not implemented yet")); -cp - return NULL; + struct ip6_hdr *hdr; + struct nd_neighbor_solicit *ns; + struct nd_opt_hdr *opt; + subnet_t *subnet; + uint16_t checksum; + + struct { + struct in6_addr ip6_src; /* source address */ + struct in6_addr ip6_dst; /* destination address */ + uint32_t length; + uint32_t next; + } pseudo; + + cp(); + + 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)); + + /* First, snatch the source address from the neighbor solicitation packet */ + + if(overwrite_mac) + memcpy(mymac.x, packet->data + 6, 6); + + /* 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")); + 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.next = htonl(IPPROTO_ICMPV6); + + /* Generate checksum */ + + checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); + checksum = inet_checksum(ns, sizeof(*ns) + 8, checksum); + + if(checksum) { + 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); + + 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])); + + return; + } + + /* Check if it is for our own subnet */ + + if(subnet->owner == myself) + return; /* silently ignore */ + + /* 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(&hdr->ip6_dst, &hdr->ip6_src, 16); /* swap destination and source protocol address */ + memcpy(&hdr->ip6_src, &ns->nd_ns_target, 16); /* ... */ + + memcpy((char *) opt + sizeof(*opt), packet->data + ETHER_ADDR_LEN, 6); /* 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; + + /* 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.next = htonl(IPPROTO_ICMPV6); + + /* Generate checksum */ + + checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0); + checksum = inet_checksum(ns, sizeof(*ns) + 8, checksum); + + ns->nd_ns_hdr.icmp6_cksum = checksum; + + write_packet(packet); +} + +/* RFC 826 */ + +static void route_arp(vpn_packet_t *packet) +{ + struct ether_arp *arp; + subnet_t *subnet; + uint8_t ipbuf[4]; + + cp(); + + /* First, snatch the source address from the ARP packet */ + + if(overwrite_mac) + memcpy(mymac.x, packet->data + 6, 6); + + /* 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) + */ + + arp = (struct ether_arp *)(packet->data + 14); + + /* 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")); + return; + } + + /* Check if the IPv4 address exists on the VPN */ + + 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]); + return; + } + + /* Check if it is for our own subnet */ + + 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(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, 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); + + write_packet(packet); +} + +void route_outgoing(vpn_packet_t *packet) +{ + uint16_t type; + node_t *n = NULL; + + cp(); + + if(packet->len < 14) { + ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet")); + return; + } + + /* FIXME: multicast? */ + + switch (routing_mode) { + case RMODE_ROUTER: + type = ntohs(*((uint16_t *)(&packet->data[12]))); + switch (type) { + case 0x0800: + if(packet->len < 34) { + ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet")); + return; + } + + n = route_ipv4(packet); + break; + + case 0x86DD: + if(packet->len < 54) { + ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet")); + return; + } + + if(packet->data[20] == IPPROTO_ICMPV6 && packet->len >= 62 && packet->data[54] == ND_NEIGHBOR_SOLICIT) { + route_neighborsol(packet); + return; + } + n = route_ipv6(packet); + break; + + case 0x0806: + if(packet->len < 42) { + ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet")); + return; + } + + 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; + + case RMODE_SWITCH: + n = route_mac(packet); + if(n) + send_packet(n, packet); + else + broadcast_packet(myself, packet); + break; + + case RMODE_HUB: + broadcast_packet(myself, packet); + break; + } +} + +void route_incoming(node_t *source, vpn_packet_t *packet) +{ + if(packet->len < 14) { + ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got too short packet from %s (%s)"), + source->name, source->hostname); + return; + } + + switch (routing_mode) { + case RMODE_ROUTER: + { + node_t *n = NULL; + uint16_t type; + + type = ntohs(*((uint16_t *)(&packet->data[12]))); + switch (type) { + case 0x0800: + if(packet->len < 34) { + ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet")); + return; + } + + n = route_ipv4(packet); + break; + + case 0x86DD: + if(packet->len < 54) { + ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet")); + return; + } + + n = route_ipv6(packet); + break; + + default: + n = myself; + break; + } + + if(n) { + if(n == myself) { + if(overwrite_mac) + memcpy(packet->data, mymac.x, 6); + write_packet(packet); + } else + send_packet(n, packet); + } + } + 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); + } + } + break; + + case RMODE_HUB: + broadcast_packet(source, packet); /* Spread it on */ + write_packet(packet); + break; + } }