/*
route.c -- routing
- Copyright (C) 2000,2001 Ivo Timmermans <itimmermans@bigfoot.com>,
- 2000,2001 Guus Sliepen <guus@sliepen.warande.net>
+ Copyright (C) 2000-2005 Ivo Timmermans,
+ 2000-2009 Guus Sliepen <guus@tinc-vpn.org>
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
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- $Id: route.c,v 1.1.2.6 2001/01/07 17:09:06 guus Exp $
+ $Id$
*/
-#include "config.h"
-
-#include <utils.h>
-#include <xalloc.h>
-#include <syslog.h>
+#include "system.h"
-#include "net.h"
+#include "avl_tree.h"
#include "connection.h"
-#include "subnet.h"
+#include "ethernet.h"
+#include "ipv4.h"
+#include "ipv6.h"
+#include "logger.h"
+#include "net.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}};
+
+/* 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)
+{
+ uint16_t *p = data;
+ uint32_t checksum = prevsum ^ 0xFFFF;
+
+ while(len >= 2) {
+ checksum += *p++;
+ len -= 2;
+ }
+
+ if(len)
+ checksum += *(uint8_t *)p;
+
+ while(checksum >> 16)
+ checksum = (checksum & 0xFFFF) + (checksum >> 16);
+
+ return ~checksum;
+}
+
+static bool ratelimit(int frequency) {
+ static time_t lasttime = 0;
+ static int count = 0;
+
+ if(lasttime == now) {
+ if(++count > frequency)
+ return true;
+ } else {
+ lasttime = now;
+ count = 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)
+{
+ subnet_t *subnet;
+ avl_node_t *node;
+ connection_t *c;
+
+ cp();
-int routing_mode = RMODE_ROUTER;
+ subnet = lookup_subnet_mac(address);
-void learn_mac(connection_t *source, mac_t *address)
+ /* If we don't know this MAC address yet, store it */
+
+ 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;
+ subnet->expires = now + macexpire;
+ subnet->net.mac.address = *address;
+ 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);
+ }
+ }
+
+ if(subnet->expires)
+ subnet->expires = now + macexpire;
+}
+
+void age_subnets(void)
{
- connection_t *old;
- subnet_t *subnet;
-cp
- old = lookup_subnet_mac(address)->owner;
-
- if(!old)
- {
- subnet = new_subnet();
- subnet->type = SUBNET_MAC;
-// subnet->lasttime = gettimeofday();
- memcpy(&subnet->net.mac.address, address, sizeof(mac_t));
- subnet_add(source, subnet);
-
- if(DEBUG_LVL >= DEBUG_TRAFFIC)
- {
- syslog(LOG_DEBUG, _("Learned new MAC address %x:%x:%x:%x:%x:%x from %s (%s)"),
- address->address.x[0],
- address->address.x[1],
- address->address.x[2],
- address->address.x[3],
- address->address.x[4],
- address->address.x[5],
- cl->name, cl->hostname);
- }
- }
-}
-
-connection_t *route_mac(connection_t *source, vpn_packet_t *packet)
+ 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->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 = node2->data;
+ if(c->status.active)
+ send_del_subnet(c, s);
+ }
+
+ subnet_del(myself, s);
+ }
+ }
+}
+
+/* RFC 792 */
+
+static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code)
{
- connection_t *oldsrc, *dst;
- subnet_t *subnet;
-cp
- /* Learn source address */
-
- learn_mac(source, (mac_t *)(&packet->data[0]));
-
- /* Lookup destination address */
-
- dst = lookup_subnet_mac((mac_t *)(&packet->data[6]))->owner;
-
- if(!dst)
- 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 dst;
-}
-
-connection_t *route_ipv4(vpn_packet_t *packet)
+ struct ip ip = {0};
+ struct icmp icmp = {0};
+
+ struct in_addr ip_src;
+ struct in_addr ip_dst;
+ uint32_t oldlen;
+
+ 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 */
+
+ memcpy(&ip, packet->data + ether_size, ip_size);
+
+ /* Remember original source and destination */
+
+ 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(packet->data + ether_size + ip_size + icmp_size, packet->data + ether_size, oldlen);
+
+ /* Fill in IPv4 header */
+
+ 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 = type;
+ icmp.icmp_code = code;
+ icmp.icmp_cksum = 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;
+
+ cp();
+
+ memcpy(&ip, packet->data + ether_size, ip_size);
+ fragment.priority = packet->priority;
+
+ if(ip.ip_hl != ip_size / 4)
+ return;
+
+ 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 void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
{
- ipv4_t dest;
- connection_t *cl;
-cp
- dest = ntohl(*((unsigned long*)(&packet->data[30])));
-
- cl = lookup_subnet_ipv4(&dest)->owner;
- 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;
-}
-
-connection_t *route_ipv6(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];
+
+ 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);
+ }
+
+ return;
+ }
+
+ send_packet(subnet->owner, packet);
+}
+
+static void route_ipv4(node_t *source, vpn_packet_t *packet)
{
-cp
- if(debug_lvl > DEBUG_NOTHING)
- {
- syslog(LOG_WARNING, _("Cannot route packet: IPv6 routing not yet implemented"));
- }
-cp
- return NULL;
+ cp();
+
+ 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);
}
-void route_outgoing(vpn_packet_t *packet)
+/* RFC 2463 */
+
+static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code)
{
- unsigned short int type;
- avl_tree_t *node;
- connection_t *cl;
-cp
- /* FIXME: multicast? */
-
- switch(routing_mode)
- {
- case RMODE_ROUTER:
- type = ntohs(*((unsigned short*)(&packet->data[12])));
- switch(type)
- {
- case 0x0800:
- cl = route_ipv4(packet);
- break;
- case 0x86DD:
- cl = route_ipv6(packet);
- break;
- default:
- if(debug_lvl >= DEBUG_TRAFFIC)
- {
- syslog(LOG_WARNING, _("Cannot route packet: unknown type %hx"), type);
- }
- return;
- }
- send_packet(cl, packet);
- break;
-
- case RMODE_SWITCH:
- cl = route_mac(packet);
- if(cl)
- send_packet(cl, packet);
- break;
-
- case RMODE_HUB:
- for(node = connection_tree->head; node; node = node->next)
- {
- cl = (connection_t *)node->data;
- if(cl->status.active)
- send_packet(cl, packet);
- }
- break;
- }
-}
-
-void route_incoming(connection_t *source, vpn_packet_t *packet)
+ struct ip6_hdr ip6;
+ struct icmp6_hdr icmp6 = {0};
+ 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(3))
+ return;
+
+ cp();
+
+ /* Swap Ethernet source and destination addresses */
+
+ swap_mac_addresses(packet);
+
+ /* Copy headers from packet to structs on the stack */
+
+ memcpy(&ip6, packet->data + ether_size, ip6_size);
+
+ /* Remember original source and destination */
+
+ 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(packet->data + ether_size + ip6_size + icmp6_size, packet->data + ether_size, pseudo.length);
+
+ /* Fill in IPv6 header */
+
+ 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 */
+
+ icmp6.icmp6_type = type;
+ icmp6.icmp6_code = code;
+ icmp6.icmp6_cksum = 0;
+
+ /* Create pseudo header */
+
+ pseudo.length = htonl(icmp6_size + pseudo.length);
+ pseudo.next = htonl(IPPROTO_ICMPV6);
+
+ /* Generate checksum */
+
+ checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
+ 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;
+
+ /* 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 = ether_size + ip6_size + ntohl(pseudo.length);
+
+ send_packet(source, packet);
+}
+
+static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet)
{
- switch(routing_mode)
- {
- case RMODE_SWITCH:
- learn_mac(source, &packet->data[0]);
- break;
- }
-
- accept_packet(packet);
+ subnet_t *subnet;
+ node_t *via;
+ ipv6_t dest;
+
+ cp();
+
+ memcpy(&dest, &packet->data[38], sizeof dest);
+ subnet = lookup_subnet_ipv6(&dest);
+
+ if(!subnet) {
+ 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(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+
+ 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);
+ 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(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 */
+ struct in6_addr ip6_dst; /* destination address */
+ uint32_t length;
+ 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 */
+
+ 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 + ETH_ALEN, ETH_ALEN);
+
+ /* Check if this is a valid 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 */
+
+ 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, 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"));
+ 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 + 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 */
+
+ ip6.ip6_dst = ip6.ip6_src; /* swap destination and source protocoll address */
+ ip6.ip6_src = ns.nd_ns_target;
+
+ 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_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 */
+
+ 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, 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);
+
+ send_packet(source, packet);
+}
+
+static void route_ipv6(node_t *source, vpn_packet_t *packet)
+{
+ cp();
+
+ if(!checklength(source, packet, ether_size + ip6_size))
+ return;
+
+ 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(node_t *source, vpn_packet_t *packet)
+{
+ struct ether_arp arp;
+ subnet_t *subnet;
+ struct in_addr addr;
+
+ cp();
+
+ if(!checklength(source, packet, ether_size + arp_size))
+ return;
+
+ 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 + ETH_ALEN, ETH_ALEN);
+
+ /* Copy headers from packet to structs on the stack */
+
+ 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) != 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);
+
+ 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 + 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(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);
+
+ /* Copy structs on stack back to packet */
+
+ memcpy(packet->data + ether_size, &arp, arp_size);
+
+ send_packet(source, packet);
+}
+
+static void route_mac(node_t *source, vpn_packet_t *packet)
+{
+ subnet_t *subnet;
+ mac_t dest;
+
+ cp();
+
+
+ /* Learn source address */
+
+ if(source == myself) {
+ mac_t src;
+ memcpy(&src, &packet->data[6], sizeof src);
+ learn_mac(&src);
+ }
+
+ /* Lookup destination address */
+
+ memcpy(&dest, &packet->data[0], sizeof dest);
+ subnet = lookup_subnet_mac(&dest);
+
+ 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(node_t *source, vpn_packet_t *packet)
+{
+ cp();
+
+ if(!checklength(source, packet, ether_size))
+ return;
+
+ switch (routing_mode) {
+ case RMODE_ROUTER:
+ {
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+ switch (type) {
+ case ETH_P_ARP:
+ route_arp(source, packet);
+ break;
+
+ case ETH_P_IP:
+ route_ipv4(source, packet);
+ break;
+
+ case ETH_P_IPV6:
+ route_ipv6(source, packet);
+ break;
+
+ 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:
+ route_mac(source, packet);
+ break;
+
+ case RMODE_HUB:
+ broadcast_packet(source, packet);
+ break;
+ }
}
projects / tinc / blobdiff