[dpdk-dev] [PATCH v2 2/4] net/tap: fix Rx cksum flags on TCP packets
From: Olivier Matz <hidden>
Date: 2021-06-30 13:52:44
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Since commit d5df2ae0428a ("net: fix unneeded replacement of TCP
checksum 0"), the functions rte_ipv4_udptcp_cksum() or
rte_ipv6_udptcp_cksum() can return either 0x0000 or 0xffff when used to
verify a packet containing a valid checksum.
This new behavior broke the checksum verification in tap driver for TCP
packets: these packets are marked with PKT_RX_L4_CKSUM_BAD.
Fix this by checking the 2 possible values. A next commit will introduce
a checksum verification helper to simplify this a bit.
Fixes: d5df2ae0428a ("net: fix unneeded replacement of TCP checksum 0")
Cc: stable@dpdk.org
Signed-off-by: Olivier Matz <redacted>
Acked-by: Andrew Rybchenko <redacted>
---
drivers/net/tap/rte_eth_tap.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 5513cfd2d7..5429f611c1 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c@@ -350,6 +350,8 @@ tap_verify_csum(struct rte_mbuf *mbuf) return; } if (l4 == RTE_PTYPE_L4_UDP || l4 == RTE_PTYPE_L4_TCP) { + int cksum_ok; + l4_hdr = rte_pktmbuf_mtod_offset(mbuf, void *, l2_len + l3_len); /* Don't verify checksum for multi-segment packets. */ if (mbuf->nb_segs > 1)
@@ -367,13 +369,13 @@ tap_verify_csum(struct rte_mbuf *mbuf) return; } } - cksum = ~rte_ipv4_udptcp_cksum(l3_hdr, l4_hdr); + cksum = rte_ipv4_udptcp_cksum(l3_hdr, l4_hdr); } else { /* l3 == RTE_PTYPE_L3_IPV6, checked above */ - cksum = ~rte_ipv6_udptcp_cksum(l3_hdr, l4_hdr); + cksum = rte_ipv6_udptcp_cksum(l3_hdr, l4_hdr); } - mbuf->ol_flags |= cksum ? - PKT_RX_L4_CKSUM_BAD : - PKT_RX_L4_CKSUM_GOOD; + cksum_ok = (cksum == 0) || (cksum == 0xffff); + mbuf->ol_flags |= cksum_ok ? + PKT_RX_L4_CKSUM_GOOD : PKT_RX_L4_CKSUM_BAD; } }
--
2.29.2