From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>,
Keith Wiles <keith.wiles@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] net/tap: Allow all-zero checksum for UDP over IPv4
Date: Tue, 10 Nov 2020 15:56:05 +0000 [thread overview]
Message-ID: <6a6cdf96-3d76-6afb-d8ca-0693c09744ca@intel.com> (raw)
In-Reply-To: <ceacb366-95f1-010e-3473-f97bd625c37a@intel.com>
On 11/10/2020 2:46 PM, Ferruh Yigit wrote:
> On 11/9/2020 2:22 PM, Michael Pfeiffer wrote:
>> Unlike TCP, UDP checksums are optional and may be zero to indicate "not
>> set" [RFC 768] (except for IPv6, where this prohibited [RFC 8200]). Add
>> this special case to the checksum offload emulation in net/tap.
>>
>> Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
>> ---
>> drivers/net/tap/rte_eth_tap.c | 13 +++++++++++--
>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
>> index 2f8abb12c..e486b41c5 100644
>> --- a/drivers/net/tap/rte_eth_tap.c
>> +++ b/drivers/net/tap/rte_eth_tap.c
>> @@ -303,6 +303,7 @@ tap_verify_csum(struct rte_mbuf *mbuf)
>> uint16_t cksum = 0;
>> void *l3_hdr;
>> void *l4_hdr;
>> + struct rte_udp_hdr *udp_hdr;
>> if (l2 == RTE_PTYPE_L2_ETHER_VLAN)
>> l2_len += 4;
>> @@ -349,10 +350,18 @@ tap_verify_csum(struct rte_mbuf *mbuf)
>> /* Don't verify checksum for multi-segment packets. */
>> if (mbuf->nb_segs > 1)
>> return;
>> - if (l3 == RTE_PTYPE_L3_IPV4)
>> + if (l3 == RTE_PTYPE_L3_IPV4) {
>> + if (l4 == RTE_PTYPE_L4_UDP) {
>> + udp_hdr = (struct rte_udp_hdr *)l4_hdr;
>> + if (udp_hdr->dgram_cksum == 0) {
>> + mbuf->ol_flags |= PKT_RX_L4_CKSUM_NONE;
>> + return;
>> + }
>> + }
>> cksum = ~rte_ipv4_udptcp_cksum(l3_hdr, l4_hdr);
>> - else if (l3 == RTE_PTYPE_L3_IPV6)
>> + } else if (l3 == RTE_PTYPE_L3_IPV6) {
>> cksum = ~rte_ipv6_udptcp_cksum(l3_hdr, l4_hdr);
>> + }
>> mbuf->ol_flags |= cksum ?
>> PKT_RX_L4_CKSUM_BAD :
>> PKT_RX_L4_CKSUM_GOOD;
>>
>
> While checking this I stuck with following part:
>
> cksum = ~rte_ipv6_udptcp_cksum(l3_hdr, l4_hdr);
> ...
> mbuf->ol_flags |= cksum ?
> PKT_RX_L4_CKSUM_BAD :
> PKT_RX_L4_CKSUM_GOOD;
>
>
> Is this correct, or am I missing something, can intention be '!' here instead of
> '~' ?
This seems correct, this is related to what cksum functions return and how to
verify cksum, I will proceed with the patch.
next prev parent reply other threads:[~2020-11-10 15:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-09 14:22 Michael Pfeiffer
2020-11-10 14:46 ` Ferruh Yigit
2020-11-10 15:56 ` Ferruh Yigit [this message]
2020-11-10 16:01 ` Morten Brørup
2020-11-10 17:42 ` Ferruh Yigit
2020-11-11 7:06 ` Morten Brørup
2020-11-10 15:59 ` Ferruh Yigit
2020-11-11 7:23 ` Michael Pfeiffer
2020-11-11 9:31 ` Ferruh Yigit
2020-11-13 13:02 ` Ferruh Yigit
2020-11-13 14:03 ` [dpdk-dev] [PATCH v2] " Michael Pfeiffer
2020-11-13 14:49 ` Ferruh Yigit
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