/*
route.c -- routing
- Copyright (C) 2000-2003 Ivo Timmermans <ivo@o2w.nl>,
- 2000-2003 Guus Sliepen <guus@sliepen.eu.org>
+ 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
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: route.c,v 1.1.2.62 2003/07/22 20:55:20 guus Exp $
+ 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.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#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_IP6_H
-#include <netinet/ip6.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 "avl_tree.h"
#include "connection.h"
-#include "device.h"
#include "ethernet.h"
#include "ipv4.h"
#include "ipv6.h"
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);
+#define max(a, b) ((a) > (b) ? (a) : (b))
+
/* RFC 1071 */
-static uint16_t inet_checksum(void *data, int len, uint16_t prevsum)
-{
+static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
uint16_t *p = data;
uint32_t checksum = prevsum ^ 0xFFFF;
}
if(len)
- checksum += *(unsigned char *)p;
+ checksum += *(uint8_t *)p;
while(checksum >> 16)
checksum = (checksum & 0xFFFF) + (checksum >> 16);
return ~checksum;
}
-static bool ratelimit(void) {
+static bool ratelimit(int frequency) {
static time_t lasttime = 0;
+ static int count = 0;
- if(lasttime == now)
- return true;
+ if(lasttime == now) {
+ if(++count > frequency)
+ return true;
+ } else {
+ lasttime = now;
+ count = 0;
+ }
- lasttime = now;
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 clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *packet) {
+ if(!via || via == myself)
+ return;
+
+ /* Find TCP header */
+ int start = 0;
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+ if(type == ETH_P_IP && packet->data[23] == 6)
+ start = 14 + (packet->data[14] & 0xf) * 4;
+ else if(type == ETH_P_IPV6 && packet->data[20] == 6)
+ start = 14 + 40;
+
+ if(!start || packet->len <= start + 20)
+ return;
+
+ /* Use data offset field to calculate length of options field */
+ int len = ((packet->data[start + 12] >> 4) - 5) * 4;
+
+ /* 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 = via->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);
+ memcpy(&packet->data[0], &packet->data[6], sizeof tmp);
+ memcpy(&packet->data[6], &tmp, sizeof tmp);
+}
-static void learn_mac(mac_t *address)
-{
+static void learn_mac(mac_t *address) {
subnet_t *subnet;
avl_node_t *node;
connection_t *c;
- cp();
-
- subnet = lookup_subnet_mac(address);
+ subnet = lookup_subnet_mac(myself, address);
/* If we don't know this MAC address yet, store it */
- if(!subnet || subnet->owner != myself) {
- ifdebug(TRAFFIC) logger(LOG_INFO, _("Learned new MAC address %hx:%hx:%hx:%hx:%hx:%hx"),
+ 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;
- memcpy(&subnet->net.mac.address, address, sizeof(mac_t));
+ subnet->expires = now + macexpire;
+ subnet->net.mac.address = *address;
+ subnet->weight = 10;
subnet_add(myself, subnet);
/* And tell all other tinc daemons it's our MAC */
for(node = connection_tree->head; node; node = node->next) {
- c = (connection_t *) node->data;
+ c = node->data;
if(c->status.active)
send_add_subnet(c, subnet);
}
}
- subnet->net.mac.lastseen = now;
+ if(subnet->expires)
+ subnet->expires = now + macexpire;
}
-void age_mac(void)
-{
+void age_subnets(void) {
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 = (subnet_t *) node->data;
- if(s->type == SUBNET_MAC && s->net.mac.lastseen && s->net.mac.lastseen + macexpire < now) {
- ifdebug(TRAFFIC) logger(LOG_INFO, _("MAC address %hx:%hx:%hx:%hx:%hx:%hx expired"),
- s->net.mac.address.x[0], s->net.mac.address.x[1],
- s->net.mac.address.x[2], s->net.mac.address.x[3],
- s->net.mac.address.x[4], s->net.mac.address.x[5]);
+ 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 = (connection_t *) node2->data;
+ c = node2->data;
if(c->status.active)
send_del_subnet(c, s);
}
}
}
-static node_t *route_mac(vpn_packet_t *packet)
-{
- subnet_t *subnet;
-
- cp();
-
- /* Learn source address */
-
- learn_mac((mac_t *)(&packet->data[6]));
-
- /* Lookup destination address */
-
- subnet = lookup_subnet_mac((mac_t *)(&packet->data[0]));
-
- if(subnet)
- return subnet->owner;
- else
- return NULL;
-}
-
/* RFC 792 */
-static void route_ipv4_unreachable(vpn_packet_t *packet, uint8_t code)
-{
- struct ip *hdr;
- struct icmp *icmp;
+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())
+ 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 */
- hdr = (struct ip *)(packet->data + 14);
- icmp = (struct icmp *)(packet->data + 14 + 20);
+ memcpy(&ip, packet->data + ether_size, ip_size);
/* Remember original source and destination */
-
- memcpy(&ip_src, &hdr->ip_src, 4);
- memcpy(&ip_dst, &hdr->ip_dst, 4);
- oldlen = packet->len - 14;
- if(oldlen >= IP_MSS - sizeof(*hdr) - sizeof(*icmp))
- oldlen = IP_MSS - sizeof(*hdr) - sizeof(*icmp);
+ 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(&icmp->icmp_ip, hdr, oldlen);
+ memmove(packet->data + ether_size + ip_size + icmp_size, packet->data + ether_size, oldlen);
/* Fill in IPv4 header */
- hdr->ip_v = 4;
- hdr->ip_hl = sizeof(*hdr) / 4;
- hdr->ip_tos = 0;
- hdr->ip_len = htons(20 + 8 + oldlen);
- hdr->ip_id = 0;
- hdr->ip_off = 0;
- hdr->ip_ttl = 255;
- hdr->ip_p = IPPROTO_ICMP;
- hdr->ip_sum = 0;
- memcpy(&hdr->ip_src, &ip_dst, 4);
- memcpy(&hdr->ip_dst, &ip_src, 4);
-
- hdr->ip_sum = inet_checksum(hdr, 20, ~0);
+ 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 = ICMP_DEST_UNREACH;
- icmp->icmp_code = code;
- icmp->icmp_cksum = 0;
+ 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;
- icmp->icmp_cksum = inet_checksum(icmp, 8 + oldlen, ~0);
+ memcpy(&ip, packet->data + ether_size, ip_size);
+ fragment.priority = packet->priority;
+
+ if(ip.ip_hl != ip_size / 4)
+ return;
- packet->len = 14 + 20 + 8 + oldlen;
+ 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;
- write_packet(packet);
+ 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 node_t *route_ipv4(vpn_packet_t *packet)
-{
+static void route_ipv4_unicast(node_t *source, 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];
- subnet = lookup_subnet_ipv4((ipv4_t *) & packet->data[30]);
-
- if(!subnet) {
- ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown IPv4 destination address %d.%d.%d.%d"),
- packet->data[30], packet->data[31], packet->data[32],
- packet->data[33]);
+ via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+ 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);
+ } else {
+ fragment_ipv4_packet(via, packet);
+ }
- route_ipv4_unreachable(packet, ICMP_NET_UNKNOWN);
- return NULL;
+ return;
}
-
- if(!subnet->owner->status.reachable)
- route_ipv4_unreachable(packet, ICMP_NET_UNREACH);
- return subnet->owner;
+ clamp_mss(source, via, packet);
+
+ send_packet(subnet->owner, packet);
+}
+
+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) || (
+ 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);
}
/* RFC 2463 */
-static void route_ipv6_unreachable(vpn_packet_t *packet, uint8_t code)
-{
- struct ip6_hdr *hdr;
- struct icmp6_hdr *icmp;
+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 {
uint32_t next;
} pseudo;
- if(ratelimit())
+ if(ratelimit(3))
return;
- cp();
+ /* Swap Ethernet source and destination addresses */
+
+ swap_mac_addresses(packet);
- hdr = (struct ip6_hdr *)(packet->data + 14);
- icmp = (struct icmp6_hdr *)(packet->data + 14 + sizeof(*hdr));
+ /* Copy headers from packet to structs on the stack */
+
+ memcpy(&ip6, packet->data + ether_size, ip6_size);
/* Remember original source and destination */
-
- memcpy(&pseudo.ip6_src, &hdr->ip6_dst, 16);
- memcpy(&pseudo.ip6_dst, &hdr->ip6_src, 16);
- pseudo.length = ntohs(hdr->ip6_plen) + sizeof(*hdr);
- if(pseudo.length >= IP_MSS - sizeof(*hdr) - sizeof(*icmp))
- pseudo.length = IP_MSS - sizeof(*hdr) - sizeof(*icmp);
+ 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(((char *)icmp) + sizeof(*icmp), hdr, pseudo.length);
+ memmove(packet->data + ether_size + ip6_size + icmp6_size, packet->data + ether_size, pseudo.length);
/* Fill in IPv6 header */
- hdr->ip6_flow = htonl(0x60000000UL);
- hdr->ip6_plen = htons(sizeof(*icmp) + pseudo.length);
- hdr->ip6_nxt = IPPROTO_ICMPV6;
- hdr->ip6_hlim = 255;
- memcpy(&hdr->ip6_dst, &pseudo.ip6_dst, 16);
- memcpy(&hdr->ip6_src, &pseudo.ip6_src, 16);
+ 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 */
- icmp->icmp6_type = ICMP6_DST_UNREACH;
- icmp->icmp6_code = code;
- icmp->icmp6_cksum = 0;
+ icmp6.icmp6_type = type;
+ icmp6.icmp6_code = code;
+ icmp6.icmp6_cksum = 0;
/* Create pseudo header */
- pseudo.length = htonl(sizeof(*icmp) + pseudo.length);
+ pseudo.length = htonl(icmp6_size + pseudo.length);
pseudo.next = htonl(IPPROTO_ICMPV6);
/* Generate checksum */
checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
- checksum = inet_checksum(icmp, ntohl(pseudo.length), checksum);
+ 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 */
- icmp->icmp6_cksum = checksum;
+ memcpy(packet->data + ether_size, &ip6, ip6_size);
+ memcpy(packet->data + ether_size + ip6_size, &icmp6, icmp6_size);
- packet->len = 14 + sizeof(*hdr) + ntohl(pseudo.length);
+ packet->len = ether_size + ip6_size + ntohl(pseudo.length);
- write_packet(packet);
+ send_packet(source, packet);
}
-static node_t *route_ipv6(vpn_packet_t *packet)
-{
+static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
subnet_t *subnet;
+ node_t *via;
+ ipv6_t dest;
- cp();
-
- subnet = lookup_subnet_ipv6((ipv6_t *) & packet->data[38]);
+ memcpy(&dest, &packet->data[38], sizeof dest);
+ subnet = lookup_subnet_ipv6(&dest);
if(!subnet) {
- ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
- ntohs(*(uint16_t *) & packet->data[38]),
- ntohs(*(uint16_t *) & packet->data[40]),
- ntohs(*(uint16_t *) & packet->data[42]),
- ntohs(*(uint16_t *) & packet->data[44]),
- ntohs(*(uint16_t *) & packet->data[46]),
- ntohs(*(uint16_t *) & packet->data[48]),
- ntohs(*(uint16_t *) & packet->data[50]),
- ntohs(*(uint16_t *) & packet->data[52]));
- route_ipv6_unreachable(packet, ICMP6_DST_UNREACH_ADDR);
-
- return NULL;
+ 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(packet, ICMP6_DST_UNREACH_NOROUTE);
+ route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+
+ via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
- return subnet->owner;
+ 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);
+ return;
+ }
+
+ clamp_mss(source, via, packet);
+
+ send_packet(subnet->owner, packet);
}
/* RFC 2461 */
-static void route_neighborsol(vpn_packet_t *packet)
-{
- struct ip6_hdr *hdr;
- struct nd_neighbor_solicit *ns;
- struct nd_opt_hdr *opt;
+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 */
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;
+ }
- hdr = (struct ip6_hdr *)(packet->data + 14);
- ns = (struct nd_neighbor_solicit *)(packet->data + 14 + sizeof(*hdr));
- opt = (struct nd_opt_hdr *)(packet->data + 14 + sizeof(*hdr) + sizeof(*ns));
+ /* 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 + 6, 6);
+ 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 ||
- opt->nd_opt_type != ND_OPT_SOURCE_LINKADDR) {
- ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type 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 */
- memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16);
- memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16);
- pseudo.length = htonl(sizeof(*ns) + sizeof(*opt) + 6);
+ 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, sizeof(*ns) + 8, checksum);
+ 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"));
+ 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);
+ 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]));
+ 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;
}
/* Create neighbor advertation reply */
- memcpy(packet->data, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* copy destination address */
- packet->data[ETHER_ADDR_LEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
+ 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(&hdr->ip6_dst, &hdr->ip6_src, 16); /* swap destination and source protocol address */
- memcpy(&hdr->ip6_src, &ns->nd_ns_target, 16); /* ... */
+ ip6.ip6_dst = ip6.ip6_src; /* swap destination and source protocoll address */
+ ip6.ip6_src = ns.nd_ns_target;
- memcpy((char *) opt + sizeof(*opt), packet->data + ETHER_ADDR_LEN, 6); /* add fake source hard addr */
+ 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_hdr.icmp6_cksum = 0;
- ns->nd_ns_hdr.icmp6_type = ND_NEIGHBOR_ADVERT;
- ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[0] = 0x40; /* Set solicited flag */
- ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[1] =
- ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[2] =
- ns->nd_ns_hdr.icmp6_dataun.icmp6_un_data8[3] = 0;
- opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
+ 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 */
- memcpy(&pseudo.ip6_src, &hdr->ip6_src, 16);
- memcpy(&pseudo.ip6_dst, &hdr->ip6_dst, 16);
- pseudo.length = htonl(sizeof(*ns) + sizeof(*opt) + 6);
+ 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, sizeof(*ns) + 8, checksum);
+ 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) {
+ if(!checklength(source, packet, ether_size + ip6_size))
+ return;
- ns->nd_ns_hdr.icmp6_cksum = checksum;
+ 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;
+ }
- write_packet(packet);
+ if(packet->data[38] == 255)
+ broadcast_packet(source, packet);
+ else
+ route_ipv6_unicast(source, packet);
}
/* RFC 826 */
-static void route_arp(vpn_packet_t *packet)
-{
- struct ether_arp *arp;
+static void route_arp(node_t *source, vpn_packet_t *packet) {
+ struct ether_arp arp;
subnet_t *subnet;
- uint8_t ipbuf[4];
+ 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 + 6, 6);
+ memcpy(mymac.x, packet->data + ETH_ALEN, ETH_ALEN);
- /* This routine generates replies to ARP requests.
- You don't need to set NOARP flag on the interface anymore (which is broken on FreeBSD).
- Most of the code here is taken from choparp.c by Takamichi Tateoka (tree@mma.club.uec.ac.jp)
- */
+ /* Copy headers from packet to structs on the stack */
- arp = (struct ether_arp *)(packet->data + 14);
+ 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) != ETHERTYPE_IP ||
- arp->arp_hln != ETHER_ADDR_LEN || arp->arp_pln != 4 || ntohs(arp->arp_op) != ARPOP_REQUEST) {
- ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type 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);
+ 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]);
+ 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;
}
if(subnet->owner == myself)
return; /* silently ignore */
- memcpy(packet->data, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* copy destination address */
- packet->data[ETHER_ADDR_LEN * 2 - 1] ^= 0xFF; /* mangle source address so it looks like it's not from us */
+ 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);
- memcpy(ipbuf, arp->arp_tpa, 4); /* save protocol addr */
- memcpy(arp->arp_tpa, arp->arp_spa, 4); /* swap destination and source protocol address */
- memcpy(arp->arp_spa, ipbuf, 4); /* ... */
+ /* Copy structs on stack back to packet */
- memcpy(arp->arp_tha, arp->arp_sha, 10); /* set target hard/proto addr */
- memcpy(arp->arp_sha, packet->data + ETHER_ADDR_LEN, ETHER_ADDR_LEN); /* add fake source hard addr */
- arp->arp_op = htons(ARPOP_REPLY);
+ memcpy(packet->data + ether_size, &arp, arp_size);
- write_packet(packet);
+ send_packet(source, packet);
}
-void route_outgoing(vpn_packet_t *packet)
-{
- uint16_t type;
- node_t *n = NULL;
+static void route_mac(node_t *source, vpn_packet_t *packet) {
+ subnet_t *subnet;
+ mac_t dest;
- cp();
+ /* Learn source address */
- /* FIXME: multicast? */
+ if(source == myself) {
+ mac_t src;
+ memcpy(&src, &packet->data[6], sizeof src);
+ learn_mac(&src);
+ }
- switch (routing_mode) {
- case RMODE_ROUTER:
- type = ntohs(*((uint16_t *)(&packet->data[12])));
- switch (type) {
- case 0x0800:
- n = route_ipv4(packet);
- break;
-
- case 0x86DD:
- if(packet->data[20] == IPPROTO_ICMPV6 && packet->data[54] == ND_NEIGHBOR_SOLICIT) {
- route_neighborsol(packet);
- return;
- }
- n = route_ipv6(packet);
- break;
-
- case 0x0806:
- route_arp(packet);
- return;
-
- default:
- ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: unknown type %hx"), type);
- return;
- }
- if(n)
- send_packet(n, packet);
- break;
+ /* Lookup destination address */
- case RMODE_SWITCH:
- n = route_mac(packet);
- if(n)
- send_packet(n, packet);
- else
- broadcast_packet(myself, packet);
- break;
+ memcpy(&dest, &packet->data[0], sizeof dest);
+ subnet = lookup_subnet_mac(NULL, &dest);
- case RMODE_HUB:
- broadcast_packet(myself, packet);
- break;
+ 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 && packet->len > 590) {
+ 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 > 1294) {
+ packet->len = via->mtu;
+ route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
+ return;
+ }
}
+
+ clamp_mss(source, via, packet);
+
+ send_packet(subnet->owner, packet);
}
-void route_incoming(node_t *source, vpn_packet_t *packet)
-{
+void route(node_t *source, vpn_packet_t *packet) {
+ if(!checklength(source, packet, ether_size))
+ return;
+
switch (routing_mode) {
case RMODE_ROUTER:
{
- node_t *n = NULL;
- uint16_t type;
+ uint16_t type = packet->data[12] << 8 | packet->data[13];
- type = ntohs(*((uint16_t *)(&packet->data[12])));
switch (type) {
- case 0x0800:
- n = route_ipv4(packet);
+ case ETH_P_ARP:
+ route_arp(source, packet);
break;
- case 0x86DD:
- n = route_ipv6(packet);
+ case ETH_P_IP:
+ route_ipv4(source, packet);
break;
- default:
- n = myself;
+ case ETH_P_IPV6:
+ route_ipv6(source, packet);
break;
- }
- if(n) {
- if(n == myself) {
- if(overwrite_mac)
- memcpy(packet->data, mymac.x, 6);
- write_packet(packet);
- } else
- send_packet(n, packet);
+ 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:
- {
- subnet_t *subnet;
-
- subnet = lookup_subnet_mac((mac_t *)(&packet->data[0]));
-
- if(subnet) {
- if(subnet->owner == myself)
- write_packet(packet);
- else
- send_packet(subnet->owner, packet);
- } else {
- broadcast_packet(source, packet);
- write_packet(packet);
- }
- }
+ route_mac(source, packet);
break;
case RMODE_HUB:
- broadcast_packet(source, packet); /* Spread it on */
- write_packet(packet);
+ broadcast_packet(source, packet);
break;
}
}
projects / tinc / blobdiff