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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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60
src/net_packet.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: net_packet.c,v 1.1.2.44 2003/12/12 19:52:25 guus Exp $
$Id: net_packet.c,v 1.1.2.45 2003/12/20 19:47:52 guus Exp $
*/
#include "system.h"
@ -52,9 +52,58 @@ int keyexpires = 0;
EVP_CIPHER_CTX packet_ctx;
static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
static void send_udppacket(node_t *, vpn_packet_t *);
#define MAX_SEQNO 1073741824
void send_mtu_probe(node_t *n)
{
vpn_packet_t packet;
int len, i;
cp();
n->mtuprobes++;
for(i = 0; i < 3; i++) {
if(n->mtuprobes >= 100 || n->probedmtu >= n->mtu) {
n->mtu = n->probedmtu;
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);
if(len < 64)
len = 64;
memset(packet.data, 0, 14);
RAND_pseudo_bytes(packet.data + 14, len - 14);
packet.len = len;
ifdebug(TRAFFIC) logger(LOG_INFO, _("Sending MTU probe length %d to %s (%s)"), len, n->name, n->hostname);
send_udppacket(n, &packet);
}
n->mtuevent = xmalloc(sizeof(*n->mtuevent));
n->mtuevent->handler = (event_handler_t)send_mtu_probe;
n->mtuevent->data = n;
n->mtuevent->time = now + 1;
event_add(n->mtuevent);
}
void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
ifdebug(TRAFFIC) logger(LOG_INFO, _("Got MTU probe length %d from %s (%s)"), packet->len, n->name, n->hostname);
if(!packet->data[0]) {
packet->data[0] = 1;
send_packet(n, packet);
} else {
if(n->probedmtu < packet->len)
n->probedmtu = packet->len;
}
}
static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
{
if(level == 10) {
@ -203,7 +252,10 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
if(n->connection)
n->connection->last_ping_time = now;
receive_packet(n, inpkt);
if(!inpkt->data[12] && !inpkt->data[13])
mtu_probe_h(n, inpkt);
else
receive_packet(n, inpkt);
}
void receive_tcppacket(connection_t *c, char *buffer, int len)
@ -328,6 +380,10 @@ 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->mtu >= origlen)
n->mtu = origlen - 1;
}
return;
}