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- Add l2tp_mtu configuration option, used to define MRU, MSS.

Browse source 
- Adjust TCP MSS options in SYN and SYN,ACK packets to avoid
  fragmentation of tcp packets.
This commit is contained in:
Brendan O'Dea 2005-09-16 05:04:28 +00:00
parent 0c678c5a03
commit bde7904f92
8 changed files with 132 additions and 55 deletions
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43
ppp.c
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@ -1,6 +1,6 @@
// L2TPNS PPP Stuff
char const *cvs_id_ppp = "$Id: ppp.c,v 1.81 2005-09-15 09:34:49 bodea Exp $";
char const *cvs_id_ppp = "$Id: ppp.c,v 1.82 2005-09-16 05:04:29 bodea Exp $";
#include <stdio.h>
#include <string.h>
@ -449,8 +449,6 @@ static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
{
uint8_t *q;
int mru = session[s].mru;
if (!mru) mru = MAXMRU;
if (mru > size) mru = size;
l += 4;
@ -577,18 +575,7 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
switch (type)
{
case 1: // Maximum-Receive-Unit
{
uint16_t mru = ntohs(*(uint16_t *)(o + 2));
if (!config->ppp_mru || mru <= config->ppp_mru)
{
session[s].mru = mru;
break;
}
LOG(3, s, t, " Remote requesting MRU of %u. Rejecting.\n", mru);
mru = htons(config->ppp_mru);
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
}
session[s].mru = ntohs(*(uint16_t *)(o + 2));
break;
case 2: // Async-Control-Character-Map
@ -749,13 +736,12 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
case 1: // Maximum-Receive-Unit
if (*p == ConfigNak)
{
session[s].mru = 0;
LOG(3, s, t, " Remote requested MRU of %u; removing option\n",
ntohs(*(uint16_t *)(o + 2)));
sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
LOG(3, s, t, " Remote requested MRU of %u\n", sess_local[s].ppp_mru);
}
else
{
session[s].mru = 0;
sess_local[s].ppp_mru = 0;
LOG(3, s, t, " Remote rejected MRU negotiation\n");
}
@ -1349,6 +1335,13 @@ void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
LOG_HEX(5, "IP", p, l);
if (l < 20 || l < ntohl(*(uint32_t *)(p + 2)))
{
LOG(1, s, t, "IP packet too short %d\n", l);
STAT(tunnel_rx_errors);
return ;
}
ip = ntohl(*(uint32_t *)(p + 12));
if (l > MAXETHER)
@ -1372,6 +1365,14 @@ void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
return;
// adjust MSS on SYN and SYN,ACK packets with options
if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
{
int ihl = (p[0] & 0xf) * 4; // length of IP header
if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
adjust_tcp_mss(s, t, p, l, p + ihl);
}
// Add on the tun header
p -= 4;
*(uint32_t *) p = htonl(PKTIP);
@ -1819,10 +1820,10 @@ void sendlcp(sessionidt s, tunnelidt t)
l += 2; //Save space for length
if (session[s].mru)
if (sess_local[s].ppp_mru)
{
*l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
*(uint16_t *) l = htons(session[s].mru); l += 2;
*(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
}
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