Hello all,
My question is about neighbor packet matching algorithm for TCP. Is it
correct to expect that IP packets should have continuous ID enumeration
(i.e. iph-next.id = iph-prev.id + 1)?
~~~
lib/librte_gro/gro_tcp4.c:check_seq_option()
...
/* check if the two packets are neighbors */
tcp_dl0 = pkt0->pkt_len - pkt0->l2_len - pkt0->l3_len - tcp_hl0;
if ((sent_seq == (item->sent_seq + tcp_dl0)) &&
(ip_id == (item->ip_id + 1)))
/* append the new packet */
return 1;
else if (((sent_seq + tcp_dl) == item->sent_seq) &&
((ip_id + item->nb_merged) == item->ip_id))
/* pre-pend the new packet */
return -1;
else
return 0;
~~~
As per RFC791:
Identification: 16 bits
An identifying value assigned by the sender to aid in assembling the
fragments of a datagram.
