[dpdk-dev] [PATCH] lib/librte_net: fix bug for checksum calculating

guohongzhi guohongzhi1 at huawei.com
Fri May 15 15:08:50 CEST 2020


1.rte_ipv4_cksum will return invalid checksum value like 0xffff.(rfc1624)
2.__rte_raw_cksum should consider Big Endian.
3.checksum 0x0000 is invalid for udp, but valid for tcp.(rfc768)

Signed-off-by: guohongzhi <guohongzhi1 at huawei.com>
---
 lib/librte_net/rte_ip.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
index 1ceb7b7..4177ea7 100644
--- a/lib/librte_net/rte_ip.h
+++ b/lib/librte_net/rte_ip.h
@@ -140,7 +140,11 @@ __rte_raw_cksum(const void *buf, size_t len, uint32_t sum)
 
 	/* if length is in odd bytes */
 	if (len == 1)
+#if (RTE_BYTE_ORDER == RTE_BIG_ENDIAN)
+		sum += *((const uint8_t *)u16_buf) << 8;
+#else
 		sum += *((const uint8_t *)u16_buf);
+#endif
 
 	return sum;
 }
@@ -267,7 +271,7 @@ rte_ipv4_cksum(const struct rte_ipv4_hdr *ipv4_hdr)
 {
 	uint16_t cksum;
 	cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr));
-	return (cksum == 0xffff) ? cksum : (uint16_t)~cksum;
+	return (uint16_t)~cksum;
 }
 
 /**
@@ -324,8 +328,7 @@ 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 +347,8 @@ 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)
+	/* 0x0000 is invalid for udp, but valid for tcp. rfc768 */
+	if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
 		cksum = 0xffff;
 
 	return (uint16_t)cksum;
@@ -436,7 +440,8 @@ 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)
+	/* 0x0000 is invalid for udp, but valid for tcp. rfc768 */
+	if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP)
 		cksum = 0xffff;
 
 	return (uint16_t)cksum;
-- 
2.21.0.windows.1




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