Remove forward declaration for do_decrement_ttl.
[oweals/tinc.git] / src / route.c
index 829773180c87ab6d549e26b3d3e1577ed1c2499d..907197b8e85c6900299a0647dda1a79fe23419e9 100644 (file)
@@ -1,7 +1,7 @@
 /*
     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;
@@ -48,7 +52,10 @@ 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);
-#define max(a, b) ((a) > (b) ? (a) : (b))
+
+#ifndef MAX
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#endif
 
 /* RFC 1071 */
 
@@ -75,13 +82,14 @@ static bool ratelimit(int frequency) {
        static int count = 0;
        
        if(lasttime == now) {
-               if(++count > frequency)
+               if(count >= frequency)
                        return true;
        } else {
                lasttime = now;
                count = 0;
        }
 
+       count++;
        return false;
 }
 
@@ -93,59 +101,340 @@ static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
                return true;
 }
 
-void clamp_mss(node_t *source, node_t *via, vpn_packet_t *packet) {
-       int i;
-       int len = ((packet->data[46] >> 4) - 5) * 4;
+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);
+}
+
+/* RFC 792 */
+
+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};
+       
+       struct in_addr ip_src;
+       struct in_addr ip_dst;
+       uint32_t oldlen;
+
+       if(ratelimit(3))
+               return;
+       
+       /* 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;
+
+       /* Try to reply with an IP address assigned to the local machine */
+
+       if (type == ICMP_TIME_EXCEEDED && code == ICMP_EXC_TTL) {
+               int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+               if (sockfd != -1) {
+                       struct sockaddr_in addr;
+                       memset(&addr, 0, sizeof(addr));
+                       addr.sin_family = AF_INET;
+                       addr.sin_addr = ip.ip_src;
+                       if (!connect(sockfd, (const struct sockaddr*) &addr, sizeof(addr))) {
+                               memset(&addr, 0, sizeof(addr));
+                               addr.sin_family = AF_INET;
+                               socklen_t addrlen = sizeof(addr);
+                               if (!getsockname(sockfd, (struct sockaddr*) &addr, &addrlen) && addrlen <= sizeof(addr)) {
+                                       ip_dst = addr.sin_addr;
+                               }
+                       }
+                       close(sockfd);
+               }
+       }
+
+       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 2463 */
+
+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;      
+
+       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;
+       
+       /* 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;
+
+       /* Try to reply with an IP address assigned to the local machine */
+
+       if (type == ICMP6_TIME_EXCEEDED && code == ICMP6_TIME_EXCEED_TRANSIT) {
+               int sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
+               if (sockfd != -1) {
+                       struct sockaddr_in6 addr;
+                       memset(&addr, 0, sizeof(addr));
+                       addr.sin6_family = AF_INET6;
+                       addr.sin6_addr = ip6.ip6_src;
+                       if (!connect(sockfd, (const struct sockaddr*) &addr, sizeof(addr))) {
+                               memset(&addr, 0, sizeof(addr));
+                               addr.sin6_family = AF_INET6;
+                               socklen_t addrlen = sizeof(addr);
+                               if (!getsockname(sockfd, (struct sockaddr*) &addr, &addrlen) && addrlen <= sizeof(addr)) {
+                                       pseudo.ip6_src = addr.sin6_addr;
+                               }
+                       }
+                       close(sockfd);
+               }
+       }
+
+       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 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;
+       }
+}
+
+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[54 + i] == 0)
+               if(packet->data[start + 20 + i] == 0)
                        break;
 
-               if(packet->data[54 + i] == 1) {
+               if(packet->data[start + 20 + i] == 1) {
                        i++;
                        continue;
                }
 
-               if(i > len - 2 || i > len - packet->data[55 + i])
+               if(i > len - 2 || i > len - packet->data[start + 21 + i])
                        break;
 
-               if(packet->data[54 + i] != 2) {
-                       if(packet->data[55 + i] < 2)
+               if(packet->data[start + 20 + i] != 2) {
+                       if(packet->data[start + 21 + i] < 2)
                                break;
-                       i += packet->data[55 + i];
+                       i += packet->data[start + 21 + i];
                        continue;
                }
 
-               if(packet->data[55] != 4)
+               if(packet->data[start + 21] != 4)
                        break;
 
-               uint16_t oldmss = packet->data[56 + i] << 8 | packet->data[57 + i];
-               uint16_t newmss = via->mtu - 54;
-               uint16_t csum = packet->data[50] << 8 | packet->data[51];
+               /* Found it */
+               uint16_t oldmss = packet->data[start + 22 + i] << 8 | packet->data[start + 23 + i];
+               uint16_t newmss = mtu - start - 20;
+               uint32_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);
 
-               packet->data[56 + i] = newmss >> 8;
-               packet->data[57 + i] = newmss & 0xff;
+               /* 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 += oldmss ^ 0xffff;
                csum += newmss;
+               csum = (csum & 0xffff) + (csum >> 16);
+               csum += csum >> 16;
                csum ^= 0xffff;
-               packet->data[50] = csum >> 8;
-               packet->data[51] = csum & 0xff;
+               packet->data[start + 16] = csum >> 8;
+               packet->data[start + 17] = csum;
                break;
        }
 }
-
-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;
@@ -157,7 +446,7 @@ static void learn_mac(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",
+               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]);
 
@@ -167,6 +456,7 @@ static void learn_mac(mac_t *address) {
                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 */
 
@@ -189,7 +479,7 @@ void age_subnets(void) {
        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))
@@ -202,87 +492,23 @@ void age_subnets(void) {
                                        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) {
-       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;
-       
-       /* 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;
+static void route_broadcast(node_t *source, vpn_packet_t *packet) {
+       if(decrement_ttl && source != myself)
+               if(!do_decrement_ttl(source, packet))
+                       return;
 
-       send_packet(source, packet);
+       broadcast_packet(source, packet);
 }
 
 /* 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;
@@ -298,7 +524,7 @@ static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *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);
+               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;
        }
 
@@ -346,7 +572,7 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
                                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;
        }
        
@@ -356,27 +582,41 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
        }
 
        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(decrement_ttl && source != myself && subnet->owner != myself)
+               if(!do_decrement_ttl(source, packet))
+                       return;
 
        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 > max(via->mtu, 590) && 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 = max(via->mtu, 590);
-                       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;
        }
 
-       if(via && via != myself && packet->data[23] == 6 && packet->len >= 58 && (packet->data[46] >> 4) > 5)
-               clamp_mss(source, via, packet);
+       clamp_mss(source, via, packet);
  
        send_packet(subnet->owner, packet);
 }
@@ -385,96 +625,16 @@ 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) || (
+       if(broadcast_mode && (((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);
+                       packet->data[33] == 255)))
+               route_broadcast(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) {
-       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;
-       
-       /* 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) {
        subnet_t *subnet;
        node_t *via;
@@ -495,7 +655,7 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
                                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;
        }
 
@@ -505,17 +665,34 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
        }
 
        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);
+
+       if(decrement_ttl && source != myself && subnet->owner != myself)
+               if(!do_decrement_ttl(source, packet))
+                       return;
 
        via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
        
-       if(via && packet->len > max(via->mtu, 1294) && 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 = max(via->mtu, 1294);
-               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);
 }
 
@@ -613,6 +790,10 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
        if(subnet->owner == myself)
                return;                                 /* silently ignore */
 
+       if(decrement_ttl)
+               if(!do_decrement_ttl(source, packet))
+                       return;
+
        /* Create neighbor advertation reply */
 
        memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN);        /* copy destination address */
@@ -669,8 +850,8 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
                return;
        }
 
-       if(packet->data[38] == 255)
-               broadcast_packet(source, packet);
+       if(broadcast_mode && packet->data[38] == 255)
+               route_broadcast(source, packet);
        else
                route_ipv6_unicast(source, packet);
 }
@@ -723,6 +904,10 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
        if(subnet->owner == myself)
                return;                                 /* silently ignore */
 
+       if(decrement_ttl)
+               if(!do_decrement_ttl(source, packet))
+                       return;
+
        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 */
 
@@ -759,7 +944,7 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
        subnet = lookup_subnet_mac(NULL, &dest);
 
        if(!subnet) {
-               broadcast_packet(source, packet);
+               route_broadcast(source, packet);
                return;
        }
 
@@ -768,35 +953,60 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
                return;
        }
 
+       if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+               return;
+
+       if(decrement_ttl && source != myself && subnet->owner != myself)
+               if(!do_decrement_ttl(source, packet))
+                       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 && packet->len > 590) {
-                       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 && packet->len > 1294) {
+               } 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;
                }
        }
 
-       if(via && via != myself && (packet->data[12] << 8 | packet->data[13]) == ETH_P_IP && packet->len >= 58 && packet->data[23] == 6 && (packet->data[46] >> 4) > 5)
-               clamp_mss(source, via, packet);
+       clamp_mss(source, via, packet);
  
        send_packet(subnet->owner, packet);
 }
 
 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;
 
@@ -830,7 +1040,7 @@ void route(node_t *source, vpn_packet_t *packet) {
                        break;
 
                case RMODE_HUB:
-                       broadcast_packet(source, packet);
+                       route_broadcast(source, packet);
                        break;
        }
 }