From: George Prekas <prekageo@amazon.com>
To: Wenzhuo Lu <wenzhuo.lu@intel.com>,
Beilei Xing <beilei.xing@intel.com>,
Bernard Iremonger <bernard.iremonger@intel.com>,
Stephen Hemminger <stephen@networkplumber.org>,
Ferruh Yigit <ferruh.yigit@intel.com>,
"Harry van Haaren" <harry.van.haaren@intel.com>
Cc: <dev@dpdk.org>, George Prekas <prekageo@amazon.com>
Subject: [dpdk-dev] [PATCH v3] app/testpmd: fix IP checksum calculation
Date: Thu, 7 Jan 2021 14:42:28 -0600 [thread overview]
Message-ID: <20210107204228.20934-1-prekageo@amazon.com> (raw)
In-Reply-To: <20201205054238.12469-1-prekageo@amazon.com>
Strict-aliasing rules are violated by cast to uint16_t* in flowgen.c and
the calculated IP checksum is wrong. Use attribute __may_alias__ to fix
the problem.
Signed-off-by: George Prekas <prekageo@amazon.com>
---
v3:
* Instead of a compiler flag, use a compiler attribute.
v2:
* Instead of a compiler barrier, use a compiler flag.
---
app/test-pmd/flowgen.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/app/test-pmd/flowgen.c b/app/test-pmd/flowgen.c
index acf3e2460..cabfc688f 100644
--- a/app/test-pmd/flowgen.c
+++ b/app/test-pmd/flowgen.c
@@ -53,8 +53,11 @@ static struct rte_ether_addr cfg_ether_dst =
#define IP_DEFTTL 64 /* from RFC 1340. */
+/* Use this type to inform GCC that ip_sum violates aliasing rules. */
+typedef unaligned_uint16_t alias_int16_t __attribute__((__may_alias__));
+
static inline uint16_t
-ip_sum(const unaligned_uint16_t *hdr, int hdr_len)
+ip_sum(const alias_int16_t *hdr, int hdr_len)
{
uint32_t sum = 0;
@@ -150,7 +153,7 @@ pkt_burst_flow_gen(struct fwd_stream *fs)
next_flow);
ip_hdr->total_length = RTE_CPU_TO_BE_16(pkt_size -
sizeof(*eth_hdr));
- ip_hdr->hdr_checksum = ip_sum((unaligned_uint16_t *)ip_hdr,
+ ip_hdr->hdr_checksum = ip_sum((const alias_int16_t *)ip_hdr,
sizeof(*ip_hdr));
/* Initialize UDP header. */
--
2.17.1
next prev parent reply other threads:[~2021-01-07 20:42 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 13:59 [dpdk-dev] [PATCH] " George Prekas
2020-12-03 16:08 ` Stephen Hemminger
2020-12-03 16:35 ` George Prekas
2020-12-03 18:33 ` Stephen Hemminger
2020-12-04 8:59 ` Ferruh Yigit
2020-12-05 5:47 ` George Prekas
2020-12-05 5:42 ` [dpdk-dev] [PATCH v2] " George Prekas
2021-01-05 16:26 ` George Prekas
2021-01-06 18:02 ` Ferruh Yigit
2021-01-07 5:25 ` Stephen Hemminger
2021-01-07 5:39 ` George Prekas
2021-01-07 11:32 ` Ferruh Yigit
2021-01-07 13:06 ` Ferruh Yigit
2021-01-07 14:20 ` George Prekas
2021-01-07 15:22 ` Ferruh Yigit
2021-01-07 20:45 ` George Prekas
2021-01-07 15:50 ` Stephen Hemminger
2021-01-07 15:59 ` Ferruh Yigit
2021-01-07 16:29 ` Stephen Hemminger
2021-01-07 20:42 ` George Prekas [this message]
2021-01-18 15:20 ` [dpdk-dev] [PATCH v3] " Ferruh Yigit
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