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Improvements for PMTU discovery and IPv4 packet fragmentation.

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This commit is contained in:
Guus Sliepen 2003-12-22 11:04:17 +00:00
parent 6d41b429a2
commit 35399784b6
7 changed files with 111 additions and 38 deletions
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10
src/graph.c
View file

@ -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: graph.c,v 1.1.2.33 2003/12/20 21:25:17 guus Exp $
$Id: graph.c,v 1.1.2.34 2003/12/22 11:04:16 guus Exp $
*/
/* We need to generate two trees from the graph:
@ -231,9 +231,9 @@ void sssp_bfs(void)
avl_insert_node(node_udp_tree, node);
if(e->to->options & OPTION_PMTU_DISCOVERY) {
e->to->mtu = MTU;
e->to->mtuprobes = 0;
e->to->probedmtu = 0;
e->to->minmtu = 0;
e->to->maxmtu = MTU;
if(e->to->status.validkey)
send_mtu_probe(e->to);
}
@ -270,6 +270,10 @@ void sssp_bfs(void)
n->status.validkey = false;
n->status.waitingforkey = false;
n->maxmtu = MTU;
n->minmtu = 0;
n->mtuprobes = 0;
asprintf(&envp[0], "NETNAME=%s", netname ? : "");
asprintf(&envp[1], "DEVICE=%s", device ? : "");
asprintf(&envp[2], "INTERFACE=%s", iface ? : "");

21
src/net_packet.c
View file

@ -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: net_packet.c,v 1.1.2.46 2003/12/20 21:09:33 guus Exp $
$Id: net_packet.c,v 1.1.2.47 2003/12/22 11:04:16 guus Exp $
*/
#include "system.h"
@ -47,6 +47,10 @@
#include "utils.h"
#include "xalloc.h"
#ifdef WSAEMSGSIZE
#define EMSGSIZE WSAEMSGSIZE
#endif
int keylifetime = 0;
int keyexpires = 0;
EVP_CIPHER_CTX packet_ctx;
@ -64,20 +68,21 @@ void send_mtu_probe(node_t *n)
cp();
n->mtuprobes++;
n->mtuevent = NULL;
if(n->mtuprobes >= 10 && !n->probedmtu) {
if(n->mtuprobes >= 10 && !n->minmtu) {
ifdebug(TRAFFIC) logger(LOG_INFO, _("No response to MTU probes from %s (%s)"), n->name, n->hostname);
return;
}
for(i = 0; i < 3; i++) {
if(n->mtuprobes >= 30 || n->probedmtu >= n->mtu) {
n->mtu = n->probedmtu;
if(n->mtuprobes >= 30 || n->minmtu >= n->maxmtu) {
n->mtu = n->minmtu;
ifdebug(TRAFFIC) logger(LOG_INFO, _("Fixing MTU of %s (%s) to %d after %d probes"), n->name, n->hostname, n->mtu, n->mtuprobes);
return;
}
len = n->probedmtu + 1 + random() % (n->mtu - n->probedmtu);
len = n->minmtu + 1 + random() % (n->maxmtu - n->minmtu);
if(len < 64)
len = 64;
@ -104,8 +109,8 @@ void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
packet->data[0] = 1;
send_packet(n, packet);
} else {
if(n->probedmtu < packet->len)
n->probedmtu = packet->len;
if(n->minmtu < packet->len)
n->minmtu = packet->len;
}
}
@ -386,6 +391,8 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
if(errno == EMSGSIZE) {
if(n->maxmtu >= origlen)
n->maxmtu = origlen - 1;
if(n->mtu >= origlen)
n->mtu = origlen - 1;
}

18
src/net_socket.c
View file

@ -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: net_socket.c,v 1.1.2.37 2003/12/20 21:09:33 guus Exp $
$Id: net_socket.c,v 1.1.2.38 2003/12/22 11:04:16 guus Exp $
*/
#include "system.h"
@ -163,13 +163,9 @@ int setup_vpn_in_socket(const sockaddr_t *sa)
{
bool choice;
if(sa->sa.sa_family == AF_INET && get_config_bool(lookup_config(myself->connection->config_tree, "PMTUDiscovery"), &choice) && choice) {
if(get_config_bool(lookup_config(myself->connection->config_tree, "PMTUDiscovery"), &choice) && choice) {
option = IP_PMTUDISC_DO;
if(setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, &option, sizeof(option))) {
closesocket(nfd);
logger(LOG_ERR, _("Can't set PMTU discovery mode: %s"), strerror(errno));
return -1;
}
setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, &option, sizeof(option));
}
}
#endif
@ -178,13 +174,9 @@ int setup_vpn_in_socket(const sockaddr_t *sa)
{
bool choice;
if(sa->sa.sa_family == AF_INET6 && get_config_bool(lookup_config(myself->connection->config_tree, "PMTUDiscovery"), &choice) && choice) {
if(get_config_bool(lookup_config(myself->connection->config_tree, "PMTUDiscovery"), &choice) && choice) {
option = IPV6_PMTUDISC_DO;
if(setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option))) {
closesocket(nfd);
logger(LOG_ERR, _("Can't set PMTU discovery mode: %s"), strerror(errno));
return -1;
}
setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option));
}
}
#endif

10
src/node.c
View file

@ -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: node.c,v 1.1.2.30 2003/12/20 21:25:17 guus Exp $
$Id: node.c,v 1.1.2.31 2003/12/22 11:04:16 guus Exp $
*/
#include "system.h"
@ -81,6 +81,7 @@ node_t *new_node(void)
n->queue = list_alloc((list_action_t) free);
EVP_CIPHER_CTX_init(&n->packet_ctx);
n->mtu = MTU;
n->maxmtu = MTU;
return n;
}
@ -110,6 +111,9 @@ void free_node(node_t *n)
sockaddrfree(&n->address);
EVP_CIPHER_CTX_cleanup(&n->packet_ctx);
if(n->mtuevent)
event_del(n->mtuevent);
free(n);
}
@ -180,11 +184,11 @@ void dump_nodes(void)
for(node = node_tree->head; node; node = node->next) {
n = node->data;
logger(LOG_DEBUG, _(" %s at %s cipher %d digest %d maclength %d compression %d options %lx status %04x nexthop %s via %s probedmtu %d"),
logger(LOG_DEBUG, _(" %s at %s cipher %d digest %d maclength %d compression %d options %lx status %04x nexthop %s via %s pmtu %d (min %d max %d)"),
n->name, n->hostname, n->cipher ? n->cipher->nid : 0,
n->digest ? n->digest->type : 0, n->maclength, n->compression,
n->options, *(uint32_t *)&n->status, n->nexthop ? n->nexthop->name : "-",
n->via ? n->via->name : "-", n->probedmtu);
n->via ? n->via->name : "-", n->mtu, n->minmtu, n->maxmtu);
}
logger(LOG_DEBUG, _("End of nodes."));

5
src/node.h
View file

@ -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: node.h,v 1.1.2.30 2003/12/20 19:47:52 guus Exp $
$Id: node.h,v 1.1.2.31 2003/12/22 11:04:16 guus Exp $
*/
#ifndef __TINC_NODE_H__
@ -74,7 +74,8 @@ typedef struct node_t {
unsigned char late[16]; /* Bitfield marking late packets */
length_t mtu; /* Maximum size of packets to send to this node */
length_t probedmtu; /* Probed MTU */
length_t minmtu; /* Probed minimum MTU */
length_t maxmtu; /* Probed maximum MTU */
int mtuprobes; /* Number of probes */
event_t *mtuevent; /* Probe event */
} node_t;

12
src/protocol_auth.c
View file

@ -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: protocol_auth.c,v 1.1.4.33 2003/12/20 21:25:17 guus Exp $
$Id: protocol_auth.c,v 1.1.4.34 2003/12/22 11:04:16 guus Exp $
*/
#include "system.h"
@ -479,6 +479,8 @@ bool send_ack(connection_t *c)
if((get_config_bool(lookup_config(c->config_tree, "PMTUDiscovery"), &choice) && choice) || myself->options & OPTION_PMTU_DISCOVERY)
c->options |= OPTION_PMTU_DISCOVERY;
get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight);
return send_request(c, "%d %s %d %lx", ACK, myport, c->estimated_weight, c->options);
}
@ -519,7 +521,7 @@ bool ack_h(connection_t *c)
{
char hisport[MAX_STRING_SIZE];
char *hisaddress, *dummy;
int weight;
int weight, mtu;
long int options;
node_t *n;
@ -554,6 +556,12 @@ bool ack_h(connection_t *c)
c->node = n;
c->options |= options;
if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
n->mtu = mtu;
if(get_config_int(lookup_config(myself->connection->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
n->mtu = mtu;
/* Activate this connection */
c->allow_request = ALL;

73
src/route.c
View file

@ -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 1.1.2.73 2003/12/20 21:25:17 guus Exp $
$Id: route.c,v 1.1.2.74 2003/12/22 11:04:17 guus Exp $
*/
#include "system.h"
@ -276,6 +276,58 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
send_packet(source, packet);
}
/* RFC 791 */
static __inline__ 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;
cp();
memcpy(&ip, packet->data + ether_size, ip_size);
fragment.priority = packet->priority;
if(ip.ip_hl != ip_size / 4)
return;
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 (%d)"), 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;
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 __inline__ void route_ipv4_unicast(node_t *source, vpn_packet_t *packet)
{
subnet_t *subnet;
@ -304,16 +356,21 @@ static __inline__ 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);
if(subnet->owner->options & OPTION_PMTU_DISCOVERY && 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];
if(subnet->owner->options & OPTION_PMTU_DISCOVERY && 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);
if(packet->data[20] & 0x40) {
packet->len = subnet->owner->mtu;
route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
} else {
fragment_ipv4_packet(subnet->owner, packet);
}
return;
}
send_packet(subnet->owner, packet);
}