bugfix: udptcp_checksum should tread tcp and udp differently

Message ID 20200527144003.3592-1-guohongzhi1@huawei.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series bugfix: udptcp_checksum should tread tcp and udp differently |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/iol-intel-Performance success Performance Testing PASS
ci/iol-nxp-Performance success Performance Testing PASS
ci/travis-robot warning Travis build: failed
ci/iol-mellanox-Performance success Performance Testing PASS
ci/iol-testing warning Testing issues
ci/Intel-compilation success Compilation OK

Commit Message

Hongzhi Guo May 27, 2020, 2:40 p.m. UTC
  RFC 768 for UDP specifies:
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.

RFC 793 for TCP has no such special treatment for the checksum of zero.

Signed-off-by: guohongzhi <guohongzhi1@huawei.com>
---
 lib/librte_net/rte_ip.h | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)
  

Patch

diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
index 1ceb7b7..8bef313 100644
--- a/lib/librte_net/rte_ip.h
+++ b/lib/librte_net/rte_ip.h
@@ -324,8 +324,7 @@  rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
  * @param l4_hdr
  *   The pointer to the beginning of the L4 header.
  * @return
- *   The complemented checksum to set in the IP packet
- *   or 0 on error
+ *   The complemented checksum to set in the IP packet.
  */
 static inline uint16_t
 rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
@@ -344,7 +343,10 @@  rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
 
 	cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
 	cksum = (~cksum) & 0xffff;
-	if (cksum == 0)
+	/* For Udp, if the computed checksum is zero,
+	 * it is transmitted as all ones.RFC768
+	 */
+	if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
 		cksum = 0xffff;
 
 	return (uint16_t)cksum;
@@ -436,7 +438,10 @@  rte_ipv6_udptcp_cksum(const struct rte_ipv6_hdr *ipv6_hdr, const void *l4_hdr)
 
 	cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
 	cksum = (~cksum) & 0xffff;
-	if (cksum == 0)
+	/* For Udp, if the computed checksum is zero,
+	 * it is transmitted as all ones.RFC768
+	 */
+	if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP)
 		cksum = 0xffff;
 
 	return (uint16_t)cksum;