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Let tinc figure out the exact MTU of the link.

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This commit is contained in:
Guus Sliepen 2003-12-20 19:47:53 +00:00
parent e8fbef5de6
commit 6b12bea62f
12 changed files with 193 additions and 78 deletions
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40
src/route.c
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@ -17,7 +17,7 @@
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id: route.c,v 1.1.2.71 2003/12/13 21:50:26 guus Exp $
$Id: route.c,v 1.1.2.72 2003/12/20 19:47:53 guus Exp $
*/
#include "system.h"
@ -206,7 +206,7 @@ static __inline__ void route_mac(node_t *source, vpn_packet_t *packet)
/* RFC 792 */
static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t code)
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};
@ -231,6 +231,9 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
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;
@ -256,7 +259,7 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
/* Fill in ICMP header */
icmp.icmp_type = ICMP_DEST_UNREACH;
icmp.icmp_type = type;
icmp.icmp_code = code;
icmp.icmp_cksum = 0;
@ -269,7 +272,7 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
memcpy(packet->data + ether_size + ip_size, &icmp, icmp_size);
packet->len = ether_size + ip_size + icmp_size + oldlen;
send_packet(source, packet);
}
@ -289,7 +292,7 @@ static __inline__ void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
packet->data[32],
packet->data[33]);
route_ipv4_unreachable(source, packet, ICMP_NET_UNKNOWN);
route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
return;
}
@ -299,7 +302,14 @@ static __inline__ void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
}
if(!subnet->owner->status.reachable)
route_ipv4_unreachable(source, packet, ICMP_NET_UNREACH);
route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
if(subnet->owner->options & OPTION_DONTFRAGMENT && packet->len > subnet->owner->mtu && subnet->owner != myself) {
ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, subnet->owner->mtu);
packet->len = subnet->owner->mtu;
route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
return;
}
if(priorityinheritance)
packet->priority = packet->data[15];
@ -319,7 +329,7 @@ static __inline__ void route_ipv4(node_t *source, vpn_packet_t *packet)
/* RFC 2463 */
static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t code)
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};
@ -347,6 +357,9 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
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;
@ -366,7 +379,7 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
/* Fill in ICMP header */
icmp6.icmp6_type = ICMP6_DST_UNREACH;
icmp6.icmp6_type = type;
icmp6.icmp6_code = code;
icmp6.icmp6_cksum = 0;
@ -413,7 +426,7 @@ static __inline__ void route_ipv6_unicast(node_t *source, vpn_packet_t *packet)
ntohs(*(uint16_t *) &packet->data[50]),
ntohs(*(uint16_t *) &packet->data[52]));
route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH_ADDR);
route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
return;
}
@ -423,8 +436,15 @@ static __inline__ void route_ipv6_unicast(node_t *source, vpn_packet_t *packet)
}
if(!subnet->owner->status.reachable)
route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH_NOROUTE);
route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
if(subnet->owner->options & OPTION_DONTFRAGMENT && packet->len > subnet->owner->mtu && subnet->owner != myself) {
ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, subnet->owner->mtu);
packet->len = subnet->owner->mtu;
route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
return;
}
send_packet(subnet->owner, packet);
}