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decode IP header from samples of MPLS-encapsulated packets #49

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decode IP header from samples of MPLS-encapsulated packets #49

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20 changes: 20 additions & 0 deletions src/sflowtool.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1605,6 +1605,26 @@ static void decodeLinkLayer(SFSample *sample)
sample->s.gotIPV6 = YES;
sample->s.offsetToIPV6 = (ptr - start);
}

if(type_len == 0x8847) {
/* MPLS unicast - 4 bytes */
ptr += 4;
/* look at first byte of possible IP header.... */
if((*ptr >> 4) == 4) {
/* IPV4 - check again that we have enough header bytes */
if((end - ptr) < sizeof(struct myiphdr)) return;
if((*ptr & 15) < 5) return; /* not IP (hdr len must be 5 quads or more) */
/* survived all the tests - store the offset to the start of the ip header */
sample->s.gotIPV4 = YES;
sample->s.offsetToIPV4 = (ptr - start);
}
else if((*ptr >> 4) == 6) {
/* IPV6 */
/* survived all the tests - store the offset to the start of the ip6 header */
sample->s.gotIPV6 = YES;
sample->s.offsetToIPV6 = (ptr - start);
}
}
}

/*_________________---------------------------__________________
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