07/07/2023 14:26, Radu Nicolau пишет:
On 07-Jul-23 1:51 PM, Xiao Liang wrote:
sa->hdr_len and prm->tun.hdr_len don't include L2 length so both should
start in the diagram at the end of the ETH header.
So the right way to compute datagram length is
dgram_len = mb->pkt_len - sqh_len - sa->hdr_l3_off - sa->hdr_len +
sizeof(struct rte_udp_hdr)
|<- mb->pkt_len - sqh_len ->|
|<- sa->hdr_l3_off ->|<- sa->hdr_len ->|
|<- udph->dgram_len ->|
+--------------------+------------+-----+-----+---------+-----+
| ETH | IP | UDP | ESP | payload | sqh |
+--------------------+------------+-----+-----+---------+-----+
|<- sa->hdr_l3_off ->|<- l3_len ->|
|<- sa->hdr_len ->|
If hdr_len doesn't include L2 length, I would agree that
dgram_len = mb->pkt_len - sqh_len - sa->hdr_l3_off - sa->hdr_len +
sizeof(struct rte_udp_hdr)
But then what's the point of
sa->hdr_len - sa->hdr_l3_off
in lib/ipsec/sa.c?
I will defer to Konstantin for a definite answer, that is if sa->hdr_len
is supposed to include l2 length / offset or not. If it does, then the
change that triggered this discussion is correct and we don't need to
account for hdr_l3_off there.
Ok, have to revive my memories here.
So, actually hdr_len stands for all tunell headers users want to add.
It consits of optional l2_len (could be zero) plus outer ip len, plus
in that case udp hdr len.
hdr_l3_off is an offset withih hdr_len where outer ip header starts.
So yep, initial patch looks ok to me, I just acked it.
Sorry for being a bit sloppy at reviewing it.
