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Handle unicast packets larger than PMTU in switch mode.

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If PMTUDiscovery is enabled, and we see a unicast packet that is larger than
the path MTU in switch mode, treat it just like we would do in router mode.
This commit is contained in:
Guus Sliepen 2009-09-12 14:19:36 +02:00
parent 7242868b64
commit 9915f2abbe
1 changed files with 74 additions and 36 deletions
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110
src/route.c
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@ -94,6 +94,13 @@ static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
} else
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);
}
static void learn_mac(mac_t *address)
{
@ -160,40 +167,6 @@ void age_subnets(void)
}
}
static void route_mac(node_t *source, vpn_packet_t *packet)
{
subnet_t *subnet;
mac_t dest;
cp();
/* Learn source address */
if(source == myself) {
mac_t src;
memcpy(&src, &packet->data[6], sizeof src);
learn_mac(&src);
}
/* Lookup destination address */
memcpy(&dest, &packet->data[0], sizeof dest);
subnet = lookup_subnet_mac(&dest);
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;
}
send_packet(subnet->owner, packet);
}
/* RFC 792 */
static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code)
@ -210,6 +183,10 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
cp();
/* 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);
@ -406,6 +383,10 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
cp();
/* 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);
@ -743,6 +724,64 @@ static void route_arp(node_t *source, vpn_packet_t *packet)
send_packet(source, packet);
}
static void route_mac(node_t *source, vpn_packet_t *packet)
{
subnet_t *subnet;
mac_t dest;
cp();
/* Learn source address */
if(source == myself) {
mac_t src;
memcpy(&src, &packet->data[6], sizeof src);
learn_mac(&src);
}
/* Lookup destination address */
memcpy(&dest, &packet->data[0], sizeof dest);
subnet = lookup_subnet_mac(&dest);
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) {
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);
}
} else if(type == ETH_P_IPV6) {
packet->len = via->mtu;
route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
} else
ifdebug(TRAFFIC) logger(LOG_INFO, _("Large packet of unhandled type %hx dropped"), type);
return;
}
send_packet(subnet->owner, packet);
}
void route(node_t *source, vpn_packet_t *packet)
{
cp();
@ -753,9 +792,8 @@ void route(node_t *source, vpn_packet_t *packet)
switch (routing_mode) {
case RMODE_ROUTER:
{
uint16_t type;
uint16_t type = packet->data[12] << 8 | packet->data[13];
type = ntohs(*((uint16_t *)(&packet->data[12])));
switch (type) {
case ETH_P_ARP:
route_arp(source, packet);