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gre: don't drop pptp packets when smaller than v4 header

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This commit is contained in:
cinap_lenrek 2018-01-20 15:13:11 +01:00
parent 9d0ba6f162
commit 9840c50a3e
1 changed files with 30 additions and 32 deletions
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62
sys/src/9/ip/gre.c
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@ -558,47 +558,45 @@ greiput(Proto *proto, Ipifc *, Block *bp)
if(flags & GRE_seq)
hdrlen += 4;
if(BLEN(bp) - hdrlen < sizeof(Ip4hdr)){
print("greretunnel: packet too short (s=%V d=%V)\n",
gre->src, gre->dst);
freeb(bp);
return;
}
ip = (Ip4hdr *)(bp->rp + hdrlen);
qlock(proto);
/*
* Look for a conversation structure for this port and address, or
* match the retunnel part, or match on the raw flag.
*/
for(p = proto->conv; *p; p++) {
c = *p;
if(c->inuse == 0)
continue;
if(eproto != 0x880B && BLEN(bp) - hdrlen >= sizeof(Ip4hdr)){
ip = (Ip4hdr *)(bp->rp + hdrlen);
/*
* Do not stop this session - blocking here
* implies that etherread is blocked.
* Look for a conversation structure for this port and address, or
* match the retunnel part, or match on the raw flag.
*/
grec = c->ptcl;
if(memcmp(ip->dst, grec->hoa, sizeof ip->dst) == 0){
grepdin++;
grebdin += BLEN(bp);
gredownlink(c, bp);
qunlock(proto);
return;
}
for(p = proto->conv; *p; p++) {
c = *p;
if(memcmp(ip->src, grec->hoa, sizeof ip->src) == 0){
grepuin++;
grebuin += BLEN(bp);
greuplink(c, bp);
qunlock(proto);
return;
if(c->inuse == 0)
continue;
/*
* Do not stop this session - blocking here
* implies that etherread is blocked.
*/
grec = c->ptcl;
if(memcmp(ip->dst, grec->hoa, sizeof ip->dst) == 0){
grepdin++;
grebdin += BLEN(bp);
gredownlink(c, bp);
qunlock(proto);
return;
}
if(memcmp(ip->src, grec->hoa, sizeof ip->src) == 0){
grepuin++;
grebuin += BLEN(bp);
greuplink(c, bp);
qunlock(proto);
return;
}
}
}
/*
* when we get here, none of the forwarding tunnels matched. now
* try to match on raw and conversational sessions.