--- /dev/null
+/*
+ route.c -- routing
+ Copyright (C) 2000-2004 Ivo Timmermans <ivo@tinc-vpn.org>,
+ 2000-2004 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
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ 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.
+
+ $Id$
+*/
+
+#include "system.h"
+
+#ifdef HAVE_NET_ETHERNET_H
+#include <net/ethernet.h>
+#endif
+#ifdef HAVE_NET_IF_ARP_H
+#include <net/if_arp.h>
+#endif
+#ifdef HAVE_NETINET_IP_ICMP_H
+#include <netinet/ip_icmp.h>
+#endif
+#ifdef HAVE_NETINET_ICMP6_H
+#include <netinet/icmp6.h>
+#endif
+#ifdef HAVE_NETINET_IF_ETHER_H
+#include <netinet/if_ether.h>
+#endif
+
+#include "logger/logger.h"
+#include "rt/rt.h"
+#include "rt/subnet.h"
+#include "support/avl.h"
+#include "support/ethernet.h"
+#include "support/ipv4.h"
+#include "support/ipv6.h"
+
+static 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);
+
+static struct timeval expires(int seconds) {
+ struct timeval tv;
+
+ gettimeofday(&tv, NULL);
+ tv.tv_sec += seconds;
+
+ return tv;
+}
+
+/* RFC 1071 */
+
+static __inline__ uint16_t inet_checksum(const void *data, int len, uint16_t prevsum) {
+ const 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 __inline__ bool ratelimit(int frequency) {
+ static time_t lasttime = 0;
+ static int count = 0;
+ time_t now = time(NULL);
+
+ if(lasttime == now) {
+ if(++count > frequency)
+ return true;
+ } else {
+ lasttime = now;
+ count = 0;
+ }
+
+ return false;
+}
+
+static __inline__ bool checklength(node_t *source, int len, int minlen) {
+ if(len < minlen) {
+ logger(LOG_WARNING, _("Got too short packet from %s"), source->name);
+ return false;
+ } else
+ return true;
+}
+
+static __inline__ void learn_mac(mac_t *address) {
+ subnet_t *subnet;
+ avl_node_t *node;
+
+ subnet = subnet_get_mac(address);
+
+ /* If we don't know this MAC address yet, store it */
+
+ if(!subnet) {
+ 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 = subnet_new();
+ subnet->type = SUBNET_TYPE_MAC;
+ subnet->expires = expires(rt_macexpire);
+ subnet->net.mac.address = *address;
+ subnet->owner = myself;
+ subnet_add(subnet);
+
+ /* And tell all other tinc daemons it's our MAC */
+
+#if 0
+ for(node = connection_tree->head; node; node = node->next) {
+ c = node->data;
+ if(c->status.active)
+ send_add_subnet(c, subnet);
+ }
+#endif
+ }
+
+ if(timerisset(&subnet->expires))
+ subnet->expires = expires(rt_macexpire);
+}
+
+void age_subnets(void) {
+ subnet_t *s;
+
+#if 0
+ for(node = myself->subnet_tree->head; node; node = next) {
+ next = node->next;
+ s = node->data;
+ if(s->expires && s->expires < now) {
+ {
+ 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);
+ }
+ }
+#endif
+}
+
+static void send_packet(node_t *dest, const uint8_t *packet, int len) {
+ if(dest == myself) {
+ rt_vnd->send(rt_vnd, packet, len);
+ } else if (dest->tnl) {
+ dest->tnl->send_packet(dest->tnl, packet, len);
+ } else {
+ logger(LOG_ERR, _("No tunnel for packet destination %s!"), dest->name);
+ }
+}
+
+static void broadcast_packet(node_t *source, const uint8_t *packet, int len) {
+ tnl_t *tnl;
+ edge_t *edge;
+
+ if(source != myself)
+ send_packet(myself, packet, len);
+
+ avl_foreach(rt_tnls, tnl, {
+ edge = tnl->data;
+ if(edge && edge->status.mst && edge->to != source)
+ send_packet(edge->to, packet, len);
+ });
+}
+
+static __inline__ void route_mac(node_t *source, const uint8_t *packet, int len) {
+ subnet_t *subnet;
+
+ /* Learn source address */
+
+ if(source == myself)
+ learn_mac((mac_t *)(packet + 6));
+
+ /* Lookup destination address */
+
+ subnet = subnet_get_mac((mac_t *)(packet));
+
+ if(!subnet) {
+ broadcast_packet(source, packet, len);
+ return;
+ }
+
+ if(subnet->owner == source) {
+ logger(LOG_WARNING, _("Packet looping back to %s!"), source->name);
+ return;
+ }
+
+ send_packet(subnet->owner, packet, len);
+}
+
+/* RFC 792 */
+
+static void route_ipv4_unreachable(node_t *source, const uint8_t *packet, int len, uint8_t type, uint8_t code) {
+ uint8_t reply[ether_size + IP_MSS];
+
+ 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;
+
+ /* Copy headers from packet into properly aligned structs on the stack */
+
+ memcpy(&ip, packet + ether_size, ip_size);
+
+ /* Remember original source and destination */
+
+ ip_src = ip.ip_src;
+ ip_dst = ip.ip_dst;
+
+ oldlen = len - ether_size;
+
+ if(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
+ icmp.icmp_nextmtu = htons(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(reply + ether_size + ip_size + icmp_size, packet + 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 + ether_size + ip_size + icmp_size, oldlen, icmp.icmp_cksum);
+
+ /* Copy structs on stack back to packet */
+
+ memcpy(reply + ether_size, &ip, ip_size);
+ memcpy(reply + ether_size + ip_size, &icmp, icmp_size);
+
+ send_packet(source, reply, ether_size + ip_size + icmp_size + oldlen);
+}
+
+/* RFC 791 */
+
+static __inline__ void fragment_ipv4_packet(node_t *dest, const uint8_t *packet, int len) {
+ struct ip ip;
+ char fragment[dest->tnl->mtu];
+ int fraglen, maxlen, todo;
+ const uint8_t *offset;
+ uint16_t ip_off, origf;
+
+ memcpy(&ip, packet + ether_size, ip_size);
+
+ if(ip.ip_hl != ip_size / 4)
+ return;
+
+ todo = ntohs(ip.ip_len) - ip_size;
+
+ if(ether_size + ip_size + todo != len) {
+ logger(LOG_WARNING, _("Length of packet (%d) doesn't match length in IPv4 header (%d)"), len, ether_size + ip_size + todo);
+ return;
+ }
+
+ logger(LOG_INFO, _("Fragmenting packet of %d bytes to %s"), len, dest->name);
+
+ offset = packet + ether_size + ip_size;
+ maxlen = (dest->tnl->mtu - ether_size - ip_size) & ~0x7;
+ ip_off = ntohs(ip.ip_off);
+ origf = ip_off & ~IP_OFFMASK;
+ ip_off &= IP_OFFMASK;
+
+ while(todo) {
+ fraglen = todo > maxlen ? maxlen : todo;
+ memcpy(fragment + ether_size + ip_size, offset, fraglen);
+ todo -= fraglen;
+ offset += fraglen;
+
+ ip.ip_len = htons(ip_size + fraglen);
+ 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, packet, ether_size);
+ memcpy(fragment + ether_size, &ip, ip_size);
+
+ send_packet(dest, fragment, ether_size + ip_size + fraglen);
+
+ ip_off += fraglen / 8;
+ }
+}
+
+static __inline__ void route_ipv4_unicast(node_t *source, const uint8_t *packet, int len) {
+ subnet_t *subnet;
+ node_t *via;
+
+ subnet = subnet_get_ipv4((ipv4_t *)(packet + 30));
+
+ if(!subnet) {
+ logger(LOG_WARNING, _("Cannot route packet from %s: unknown IPv4 destination address %d.%d.%d.%d"),
+ source->name,
+ packet[30],
+ packet[31],
+ packet[32],
+ packet[33]);
+
+ route_ipv4_unreachable(source, packet, len, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
+ return;
+ }
+
+ if(subnet->owner == source) {
+ logger(LOG_WARNING, _("Packet looping back to %s!"), source->name);
+ return;
+ }
+
+ if(!subnet->owner->status.reachable)
+ route_ipv4_unreachable(source, packet, len, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+
+ via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+ if(len > via->tnl->mtu && via != myself) {
+ logger(LOG_INFO, _("Packet for %s length %d larger than MTU %d"), subnet->owner->name, len, via->tnl->mtu);
+ if(packet[20] & 0x40) {
+ len = via->tnl->mtu;
+ route_ipv4_unreachable(source, packet, len, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
+ } else {
+ fragment_ipv4_packet(via, packet, len);
+ }
+
+ return;
+ }
+
+ send_packet(subnet->owner, packet, len);
+}
+
+static __inline__ void route_ipv4(node_t *source, const uint8_t *packet, int len) {
+ if(!checklength(source, len, ether_size + ip_size))
+ return;
+
+ route_ipv4_unicast(source, packet, len);
+}
+
+/* RFC 2463 */
+
+static void route_ipv6_unreachable(node_t *source, const uint8_t *packet, int len, uint8_t type, uint8_t code) {
+ uint8_t reply[ether_size + IP_MSS];
+ 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;
+
+ /* Copy headers from packet to structs on the stack */
+
+ memcpy(&ip6, packet + ether_size, ip6_size);
+
+ /* Remember original source and destination */
+
+ pseudo.ip6_src = ip6.ip6_dst;
+ pseudo.ip6_dst = ip6.ip6_src;
+
+ pseudo.length = 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 */
+
+ memcpy(reply + ether_size + ip6_size + icmp6_size, packet + 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(reply + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
+
+ icmp6.icmp6_cksum = checksum;
+
+ /* Copy structs on stack back to packet */
+
+ memcpy(reply + ether_size, &ip6, ip6_size);
+ memcpy(reply + ether_size + ip6_size, &icmp6, icmp6_size);
+
+ send_packet(source, reply, ether_size + ip6_size + ntohl(pseudo.length));
+}
+
+static __inline__ void route_ipv6_unicast(node_t *source, const uint8_t *packet, int len) {
+ subnet_t *subnet;
+ node_t *via;
+
+ subnet = subnet_get_ipv6((ipv6_t *)(packet + 38));
+
+ if(!subnet) {
+ logger(LOG_WARNING, _("Cannot route packet from %s: unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
+ source->name,
+ ntohs(*(uint16_t *)(packet + 38)),
+ ntohs(*(uint16_t *)(packet + 40)),
+ ntohs(*(uint16_t *)(packet + 42)),
+ ntohs(*(uint16_t *)(packet + 44)),
+ ntohs(*(uint16_t *)(packet + 46)),
+ ntohs(*(uint16_t *)(packet + 48)),
+ ntohs(*(uint16_t *)(packet + 50)),
+ ntohs(*(uint16_t *)(packet + 52)));
+
+ route_ipv6_unreachable(source, packet, len, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
+ return;
+ }
+
+ if(subnet->owner == source) {
+ logger(LOG_WARNING, _("Packet looping back to %s!"), source->name);
+ return;
+ }
+
+ if(!subnet->owner->status.reachable)
+ route_ipv6_unreachable(source, packet, len, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+
+ via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+ if(len > via->tnl->mtu && via != myself) {
+ logger(LOG_INFO, _("Packet for %s length %d larger than MTU %d"), subnet->owner->name, len, via->tnl->mtu);
+ len = via->tnl->mtu;
+ route_ipv6_unreachable(source, packet, len, ICMP6_PACKET_TOO_BIG, 0);
+ return;
+ }
+
+ send_packet(subnet->owner, packet, len);
+}
+
+/* RFC 2461 */
+
+static void route_neighborsol(node_t *source, const uint8_t *packet, int len) {
+ uint8_t reply[len];
+ struct ip6_hdr ip6;
+ 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;
+
+ if(!checklength(source, len, ether_size + ip6_size + ns_size + opt_size + ETH_ALEN))
+ return;
+
+ if(source != myself) {
+ logger(LOG_WARNING, _("Got neighbor solicitation request from %s while in router mode!"), source->name);
+ return;
+ }
+
+ /* Copy headers from packet to structs on the stack */
+
+ memcpy(&ip6, packet + ether_size, ip6_size);
+ memcpy(&ns, packet + ether_size + ip6_size, ns_size);
+ memcpy(&opt, packet + ether_size + ip6_size + ns_size, opt_size);
+
+ /* First, snatch the source address from the neighbor solicitation packet */
+
+ if(rt_overwrite_mac)
+ memcpy(mymac.x, packet + 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) {
+ 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;
+ pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
+ pseudo.next = htonl(IPPROTO_ICMPV6);
+
+ /* Generate checksum */
+
+ checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
+ checksum = inet_checksum(&ns, ns_size, checksum);
+ checksum = inet_checksum(&opt, opt_size, checksum);
+ checksum = inet_checksum(packet + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
+
+ if(checksum) {
+ logger(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request"));
+ return;
+ }
+
+ /* Check if the IPv6 address exists on the VPN */
+
+ subnet = subnet_get_ipv6((ipv6_t *) &ns.nd_ns_target);
+
+ if(!subnet) {
+ 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(reply, packet + ETH_ALEN, ETH_ALEN); /* copy destination address */
+ memcpy(reply + ETH_ALEN, packet + ETH_ALEN, ETH_ALEN); /* copy destination address */
+ reply[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;
+
+ memcpy(reply + ether_size + ip6_size + ns_size + opt_size, reply + 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;
+ pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
+ pseudo.next = htonl(IPPROTO_ICMPV6);
+
+ /* Generate checksum */
+
+ checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
+ checksum = inet_checksum(&ns, ns_size, checksum);
+ checksum = inet_checksum(&opt, opt_size, checksum);
+ checksum = inet_checksum(packet + 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(reply + ether_size, &ip6, ip6_size);
+ memcpy(reply + ether_size + ip6_size, &ns, ns_size);
+ memcpy(reply + ether_size + ip6_size + ns_size, &opt, opt_size);
+
+ send_packet(source, reply, len);
+}
+
+static __inline__ void route_ipv6(node_t *source, const uint8_t *packet, int len) {
+ if(!checklength(source, len, ether_size + ip6_size))
+ return;
+
+ if(packet[20] == IPPROTO_ICMPV6 && checklength(source, len, ether_size + ip6_size + icmp6_size) && packet[54] == ND_NEIGHBOR_SOLICIT) {
+ route_neighborsol(source, packet, len);
+ return;
+ }
+
+ route_ipv6_unicast(source, packet, len);
+}
+
+/* RFC 826 */
+
+static void route_arp(node_t *source, const uint8_t *packet, int len) {
+ uint8_t reply[len];
+ struct ether_arp arp;
+ subnet_t *subnet;
+ struct in_addr addr;
+
+ if(!checklength(source, len, ether_size + arp_size))
+ return;
+
+ if(source != myself) {
+ logger(LOG_WARNING, _("Got ARP request from %s while in router mode!"), source->name);
+ return;
+ }
+
+ /* First, snatch the source address from the ARP packet */
+
+ if(rt_overwrite_mac)
+ memcpy(mymac.x, packet + ETH_ALEN, ETH_ALEN);
+
+ /* Copy headers from packet to structs on the stack */
+
+ memcpy(&arp, packet + 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) {
+ logger(LOG_WARNING, _("Cannot route packet: received unknown type ARP request"));
+ return;
+ }
+
+ /* Check if the IPv4 address exists on the VPN */
+
+ subnet = subnet_get_ipv4((ipv4_t *) &arp.arp_tpa);
+
+ if(!subnet) {
+ 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(reply, packet + ETH_ALEN, ETH_ALEN); /* copy destination address */
+ memcpy(reply + ETH_ALEN, packet + ETH_ALEN, ETH_ALEN); /* copy destination address */
+ reply[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, reply + ETH_ALEN, ETH_ALEN); /* add fake source hard addr */
+ arp.arp_op = htons(ARPOP_REPLY);
+
+ /* Copy structs on stack back to packet */
+
+ memcpy(reply + ether_size, &arp, arp_size);
+
+ send_packet(source, reply, len);
+}
+
+void route(node_t *source, const uint8_t *packet, int len) {
+ if(!checklength(source, len, ether_size))
+ return;
+
+ switch (rt_mode) {
+ case RT_MODE_ROUTER:
+ {
+ uint16_t type;
+
+ type = ntohs(*((uint16_t *)(packet + 12)));
+ switch (type) {
+ case ETH_P_ARP:
+ route_arp(source, packet, len);
+ break;
+
+ case ETH_P_IP:
+ route_ipv4(source, packet, len);
+ break;
+
+ case ETH_P_IPV6:
+ route_ipv6(source, packet, len);
+ break;
+
+ default:
+ logger(LOG_WARNING, _("Cannot route packet from %s: unknown type %hx"), source->name, type);
+ break;
+ }
+ }
+ break;
+
+ case RT_MODE_SWITCH:
+ route_mac(source, packet, len);
+ break;
+
+ case RT_MODE_HUB:
+ broadcast_packet(source, packet, len);
+ break;
+ }
+}
projects / tinc / blobdiff