/*
route.c -- routing
Copyright (C) 2000-2005 Ivo Timmermans,
- 2000-2009 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2014 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
#include "utils.h"
rmode_t routing_mode = RMODE_ROUTER;
+fmode_t forwarding_mode = FMODE_INTERNAL;
+bmode_t broadcast_mode = BMODE_MST;
+bool decrement_ttl = false;
+bool directonly = false;
bool priorityinheritance = false;
int macexpire = 600;
bool overwrite_mac = false;
static const size_t ns_size = sizeof(struct nd_neighbor_solicit);
static const size_t opt_size = sizeof(struct nd_opt_hdr);
+#ifndef MAX
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#endif
+
/* RFC 1071 */
static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
static int count = 0;
if(lasttime == now) {
- if(++count > frequency)
+ if(count >= frequency)
return true;
} else {
lasttime = now;
count = 0;
}
+ count++;
return false;
}
return true;
}
+static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *packet) {
+ if(!source || !via || !(via->options & OPTION_CLAMP_MSS))
+ return;
+
+ uint16_t mtu = source->mtu;
+ if(via != myself && via->mtu < mtu)
+ mtu = via->mtu;
+
+ /* Find TCP header */
+ int start = ether_size;
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+ if(type == ETH_P_8021Q) {
+ start += 4;
+ type = packet->data[16] << 8 | packet->data[17];
+ }
+
+ if(type == ETH_P_IP && packet->data[start + 9] == 6)
+ start += (packet->data[start] & 0xf) * 4;
+ else if(type == ETH_P_IPV6 && packet->data[start + 6] == 6)
+ start += 40;
+ else
+ return;
+
+ if(packet->len <= start + 20)
+ return;
+
+ /* Use data offset field to calculate length of options field */
+ int len = ((packet->data[start + 12] >> 4) - 5) * 4;
+
+ if(packet->len < start + 20 + len)
+ return;
+
+ /* Search for MSS option header */
+ for(int i = 0; i < len;) {
+ if(packet->data[start + 20 + i] == 0)
+ break;
+
+ if(packet->data[start + 20 + i] == 1) {
+ i++;
+ continue;
+ }
+
+ if(i > len - 2 || i > len - packet->data[start + 21 + i])
+ break;
+
+ if(packet->data[start + 20 + i] != 2) {
+ if(packet->data[start + 21 + i] < 2)
+ break;
+ i += packet->data[start + 21 + i];
+ continue;
+ }
+
+ if(packet->data[start + 21] != 4)
+ break;
+
+ /* Found it */
+ uint16_t oldmss = packet->data[start + 22 + i] << 8 | packet->data[start + 23 + i];
+ uint16_t newmss = mtu - start - 20;
+ uint16_t csum = packet->data[start + 16] << 8 | packet->data[start + 17];
+
+ if(oldmss <= newmss)
+ break;
+
+ ifdebug(TRAFFIC) logger(LOG_INFO, "Clamping MSS of packet from %s to %s to %d", source->name, via->name, newmss);
+
+ /* Update the MSS value and the checksum */
+ packet->data[start + 22 + i] = newmss >> 8;
+ packet->data[start + 23 + i] = newmss & 0xff;
+ csum ^= 0xffff;
+ csum -= oldmss;
+ csum += newmss;
+ csum ^= 0xffff;
+ packet->data[start + 16] = csum >> 8;
+ packet->data[start + 17] = csum & 0xff;
+ break;
+ }
+}
+
static void swap_mac_addresses(vpn_packet_t *packet) {
mac_t tmp;
memcpy(&tmp, &packet->data[0], sizeof tmp);
avl_node_t *node;
connection_t *c;
- subnet = lookup_subnet_mac(address);
+ subnet = lookup_subnet_mac(myself, 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",
+ ifdebug(TRAFFIC) logger(LOG_INFO, "Learned new MAC address %x:%x:%x:%x:%x:%x",
address->x[0], address->x[1], address->x[2], address->x[3],
address->x[4], address->x[5]);
subnet->type = SUBNET_MAC;
subnet->expires = now + macexpire;
subnet->net.mac.address = *address;
+ subnet->weight = 10;
subnet_add(myself, subnet);
+ subnet_update(myself, subnet, true);
/* And tell all other tinc daemons it's our MAC */
for(node = myself->subnet_tree->head; node; node = next) {
next = node->next;
s = node->data;
- if(s->expires && s->expires < now) {
+ if(s->expires && s->expires <= now) {
ifdebug(TRAFFIC) {
char netstr[MAXNETSTR];
if(net2str(netstr, sizeof netstr, s))
send_del_subnet(c, s);
}
+ subnet_update(myself, s, false);
subnet_del(myself, s);
}
}
/* RFC 792 */
-static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code) {
+static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
struct ip ip = {0};
struct icmp icmp = {0};
/* RFC 791 */
-static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet) {
+static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet, length_t ether_size) {
struct ip ip;
vpn_packet_t fragment;
int len, maxlen, todo;
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);
+ ifdebug(TRAFFIC) logger(LOG_WARNING, "Length of packet (%d) doesn't match length in IPv4 header (%d)", packet->len, (int)(ether_size + ip_size + todo));
return;
}
dest.x[2],
dest.x[3]);
- route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
+ route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
return;
}
}
if(!subnet->owner->status.reachable)
- route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+ return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+
+ if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+ return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
if(priorityinheritance)
packet->priority = packet->data[15];
via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+ if(via == source) {
+ ifdebug(TRAFFIC) logger(LOG_ERR, "Routing loop for packet from %s (%s)!", source->name, source->hostname);
+ return;
+ }
- if(via && packet->len > via->mtu && via != myself) {
+ if(directonly && subnet->owner != via)
+ return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+
+ if(via && packet->len > MAX(via->mtu, 590) && 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);
+ packet->len = MAX(via->mtu, 590);
+ route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
} else {
- fragment_ipv4_packet(via, packet);
+ fragment_ipv4_packet(via, packet, ether_size);
}
return;
}
+ clamp_mss(source, via, packet);
+
send_packet(subnet->owner, packet);
}
if(!checklength(source, packet, ether_size + ip_size))
return;
- if(((packet->data[30] & 0xf0) == 0xe0) || (
+ if(broadcast_mode && (((packet->data[30] & 0xf0) == 0xe0) || (
packet->data[30] == 255 &&
packet->data[31] == 255 &&
packet->data[32] == 255 &&
- packet->data[33] == 255))
+ packet->data[33] == 255)))
broadcast_packet(source, packet);
else
route_ipv4_unicast(source, packet);
/* RFC 2463 */
-static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code) {
+static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
struct ip6_hdr ip6;
struct icmp6_hdr icmp6 = {0};
uint16_t checksum;
ntohs(dest.x[6]),
ntohs(dest.x[7]));
- route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
+ route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
return;
}
}
if(!subnet->owner->status.reachable)
- route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+ return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+
+ if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+ return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
- if(via && packet->len > via->mtu && via != myself) {
+ if(via == source) {
+ ifdebug(TRAFFIC) logger(LOG_ERR, "Routing loop for packet from %s (%s)!", source->name, source->hostname);
+ return;
+ }
+
+ if(directonly && subnet->owner != via)
+ return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+
+ if(via && packet->len > MAX(via->mtu, 1294) && 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);
+ packet->len = MAX(via->mtu, 1294);
+ route_ipv6_unreachable(source, packet, ether_size, ICMP6_PACKET_TOO_BIG, 0);
return;
}
+ clamp_mss(source, via, packet);
+
send_packet(subnet->owner, packet);
}
return;
}
- if(packet->data[38] == 255)
+ if(broadcast_mode && packet->data[38] == 255)
broadcast_packet(source, packet);
else
route_ipv6_unicast(source, packet);
/* Lookup destination address */
memcpy(&dest, &packet->data[0], sizeof dest);
- subnet = lookup_subnet_mac(&dest);
+ subnet = lookup_subnet_mac(NULL, &dest);
if(!subnet) {
broadcast_packet(source, packet);
return;
}
+ if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+ return;
+
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+ if(priorityinheritance && type == ETH_P_IP && packet->len >= ether_size + ip_size)
+ packet->priority = packet->data[15];
+
// Handle packets larger than PMTU
node_t *via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+ if(directonly && subnet->owner != via)
+ return;
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) {
+ length_t ethlen = 14;
+
+ if(type == ETH_P_8021Q) {
+ type = packet->data[16] << 8 | packet->data[17];
+ ethlen += 4;
+ }
+
+ if(type == ETH_P_IP && packet->len > 576 + ethlen) {
+ if(packet->data[6 + ethlen] & 0x40) {
packet->len = via->mtu;
- route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
+ route_ipv4_unreachable(source, packet, ethlen, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
} else {
- fragment_ipv4_packet(via, packet);
+ fragment_ipv4_packet(via, packet, ethlen);
}
return;
- } else if(type == ETH_P_IPV6) {
+ } else if(type == ETH_P_IPV6 && packet->len > 1280 + ethlen) {
packet->len = via->mtu;
- route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
+ route_ipv6_unreachable(source, packet, ethlen, ICMP6_PACKET_TOO_BIG, 0);
return;
}
}
+ clamp_mss(source, via, packet);
+
send_packet(subnet->owner, packet);
}
+static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
+ length_t ethlen = ether_size;
+
+ if(type == ETH_P_8021Q) {
+ type = packet->data[16] << 8 | packet->data[17];
+ ethlen += 4;
+ }
+
+ switch (type) {
+ case ETH_P_IP:
+ if(!checklength(source, packet, ethlen + ip_size))
+ return false;
+
+ if(packet->data[ethlen + 8] <= 1) {
+ if(packet->data[ethlen + 11] != IPPROTO_ICMP || packet->data[ethlen + 32] != ICMP_TIME_EXCEEDED)
+ route_ipv4_unreachable(source, packet, ethlen, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
+ return false;
+ }
+
+ uint16_t old = packet->data[ethlen + 8] << 8 | packet->data[ethlen + 9];
+ packet->data[ethlen + 8]--;
+ uint16_t new = packet->data[ethlen + 8] << 8 | packet->data[ethlen + 9];
+
+ uint32_t checksum = packet->data[ethlen + 10] << 8 | packet->data[ethlen + 11];
+ checksum += old + (~new & 0xFFFF);
+ while(checksum >> 16)
+ checksum = (checksum & 0xFFFF) + (checksum >> 16);
+ packet->data[ethlen + 10] = checksum >> 8;
+ packet->data[ethlen + 11] = checksum & 0xff;
+
+ return true;
+
+ case ETH_P_IPV6:
+ if(!checklength(source, packet, ethlen + ip6_size))
+ return false;
+
+ if(packet->data[ethlen + 7] <= 1) {
+ if(packet->data[ethlen + 6] != IPPROTO_ICMPV6 || packet->data[ethlen + 40] != ICMP6_TIME_EXCEEDED)
+ route_ipv6_unreachable(source, packet, ethlen, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
+ return false;
+ }
+
+ packet->data[ethlen + 7]--;
+
+ return true;
+
+ default:
+ return true;
+ }
+}
+
void route(node_t *source, vpn_packet_t *packet) {
+ if(forwarding_mode == FMODE_KERNEL && source != myself) {
+ send_packet(myself, packet);
+ return;
+ }
+
if(!checklength(source, packet, ether_size))
return;
+ if(decrement_ttl && source != myself)
+ if(!do_decrement_ttl(source, packet))
+ return;
+
switch (routing_mode) {
case RMODE_ROUTER:
{
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