On Fri, Jul 10, 2020 at 03:10:34PM +0200, Morten Brørup wrote: > > From: Olivier Matz [mailto:[email protected]] > > Sent: Friday, July 10, 2020 2:41 PM > > > > On Fri, Jul 10, 2020 at 02:55:51PM +0800, Hongzhi Guo wrote: > > > Per RFC768: > > > If the computed checksum is zero, it is transmitted as all ones. > > > An all zero transmitted checksum value means that the transmitter > > > generated no checksum. > > > > > > RFC793 for TCP has no such special treatment for the checksum of > > zero. > > > > > > Fixes: 6006818cfb26 ("net: new checksum functions") > > > Cc: [email protected] > > > > > > Signed-off-by: Hongzhi Guo <[email protected]> > > > --- > > > v2: > > > * Fixed commit tile > > > * Fixed the API comment > > > --- > > > --- > > > lib/librte_net/rte_ip.h | 18 +++++++++++++++--- > > > 1 file changed, 15 insertions(+), 3 deletions(-) > > > > > > diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h > > > index 292f63fd7..d03c77120 100644 > > > --- a/lib/librte_net/rte_ip.h > > > +++ b/lib/librte_net/rte_ip.h > > > @@ -325,7 +325,7 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr > > *ipv4_hdr, uint64_t ol_flags) > > > * The pointer to the beginning of the L4 header. > > > * @return > > > * The complemented checksum to set in the IP packet > > > - * or 0 on error > > > + * or 0 if the IP length is invalid in the header. > > > */ > > > static inline uint16_t > > > rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const > > void *l4_hdr) > > 0 is a valid return value, so I suggest omitting it from the return value > description: > > * @return > - * The complemented checksum to set in the IP packet > - * or 0 on error > + * The complemented checksum to set in the IP packet. > > The comparison "if (l3_len < sizeof(struct rte_ipv4_hdr))" is only there to > protect against invalid input; it prevents l4_len from becoming negative.
I don't get why "0 if the IP length is invalid in the header" should be removed from the comment: 0 is both a valid return value and the value returned on invalid packet. > For the same reason, unlikely() should be added to this comparison. Maybe yes, but that's another story I think. > Otherwise, > > Acked-by: Morten Brørup <[email protected]> >
