route.c -- routing
Copyright (C) 2000-2005 Ivo Timmermans,
2000-2014 Guus Sliepen <guus@tinc-vpn.org>
+ 2015 Vittorio Gambaletta
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
static const size_t ns_size = sizeof(struct nd_neighbor_solicit);
static const size_t opt_size = sizeof(struct nd_opt_hdr);
-static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet);
-
#ifndef MAX
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#endif
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);
+}
+
+/* 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;
csum += newmss;
csum = (csum & 0xffff) + (csum >> 16);
csum += csum >> 16;
- csum ^= 0xffff;
- 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);
+ csum ^= 0xffff;
+ packet->data[start + 16] = csum >> 8;
+ packet->data[start + 17] = csum;
+ break;
+ }
}
static void learn_mac(mac_t *address) {
broadcast_packet(source, packet);
}
-/* 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 791 */
static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet, length_t ether_size) {
route_ipv4_unicast(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 void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
subnet_t *subnet;
node_t *via;
if(!do_decrement_ttl(source, packet))
return;
+ if(priorityinheritance)
+ packet->priority = ((packet->data[14] & 0x0f) << 4) | (packet->data[15] >> 4);
+
via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
if(via == source) {
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];
+ if(priorityinheritance) {
+ if(type == ETH_P_IP && packet->len >= ether_size + ip_size)
+ packet->priority = packet->data[15];
+ else if(type == ETH_P_IPV6 && packet->len >= ether_size + ip6_size)
+ packet->priority = ((packet->data[14] & 0x0f) << 4) | (packet->data[15] >> 4);
+ }
// Handle packets larger than PMTU
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);
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