/**
* Parse the per-hop headers.
*
* Will return the absolute offset of the next byte to parse (i.e. 'endHeaders')
*
* @param [in] packet The packet buffer
* @param [in] offset The first byte to begin parsing at
* @param [in] endMessage The ceiling of bytes to parse
* @param [in] skeleton The structure to fill in
*/
static void
_parsePerHopV1(const uint8_t *packet, size_t offset, size_t endHeaders, MetisTlvSkeleton *skeleton)
{
const size_t tl_length = sizeof(MetisTlvType);
// we only parse to the end of the per-hop headers or until we've found
// the 2 headers we want (hoplimit, fragmentation header)
while (offset + sizeof(MetisTlvType) < endHeaders) {
const MetisTlvType *tlv = (MetisTlvType *) (packet + offset);
const uint16_t type = htons(tlv->type);
const uint16_t v_length = htons(tlv->length);
// move past the TL header
offset += tl_length;
size_t endSubSection = offset + v_length;
if (endSubSection <= endHeaders) {
switch (type) {
case T_INTLIFE:
metisTlvSkeleton_SetInterestLifetime(skeleton, offset, v_length);
break;
// should verify that we dont have both INTFRAG and OBJFRAG
case T_CACHETIME:
metisTlvSkeleton_SetCacheTimeHeader(skeleton, offset, v_length);
break;
default:
break;
}
}
offset = endSubSection;
}
}
static void
_parseInterestV0(const uint8_t *packet, size_t offset, size_t endMessage, MetisTlvSkeleton *skeleton)
{
int foundCount = 0;
const size_t tl_length = sizeof(MetisTlvType);
// skip the Interest wrapper
offset += 4;
// parse to the end or until we find all 5 things (name, keyid, objecthash, scope, interest lifetime)
while (offset < endMessage && foundCount < 5) {
MetisTlvType *tlv = (MetisTlvType *) (packet + offset);
uint16_t type = htons(tlv->type);
uint16_t v_length = htons(tlv->length);
// skip past the TLV header
offset += tl_length;
switch (type) {
case T_NAME:
metisTlvSkeleton_SetName(skeleton, offset, v_length);
foundCount++;
break;
case T_KEYID:
metisTlvSkeleton_SetKeyId(skeleton, offset, v_length);
foundCount++;
break;
case T_OBJHASH:
metisTlvSkeleton_SetObjectHash(skeleton, offset, v_length);
foundCount++;
break;
case T_INTLIFE:
metisTlvSkeleton_SetInterestLifetime(skeleton, offset, v_length);
foundCount++;
break;
default:
break;
}
offset += v_length;
}
}
