Re: [PATCH v5 0/5] tcp: use csum_iov() in tcp_update_check_tcp[4|6]()

[Stefano Brivio <sbrivio@redhat.com>]

On Fri, 27 Sep 2024 15:53:44 +0200
Laurent Vivier <lvivier@redhat.com> wrote:

> For vhost-user, we will need to spread TCP payload over
> several buffers. To re-use tcp_update_check_tcp[4|6](),
> provide an iovec rather than a pointer to a buffer.
> 
> This series updates also csum_iov() and pcap_iov() to
> add an offset of bytes to skip in the iovec array.
> 
> It's based on top of "tcp: Use tcp_payload_t rather than tcphdr" that
> is added in the series for convenience.
> 
> v3 adds "udp: Update UDP checksum using an iovec array" that modifies
> csum_udp4() and csum_udp6() in the same way.
> 
> Laurent Vivier (5):
>   tcp: Use tcp_payload_t rather than tcphdr
>   pcap: Add an offset argument in pcap_iov()
>   checksum: Add an offset argument in csum_iov()
>   tcp: Update TCP checksum using an iovec array
>   udp: Update UDP checksum using an iovec array

I *think* something in this series causes two test failures.

I wasn't able to reproduce them without this series (tried five times),
but I don't always reproduce them with it (tried about 10 times, I
didn't get any failure for 3 runs, one or both in the other runs).

The first one looks like this (copy and paste to a buffer to see it):

--
ns$ ip -j -4 addr show|jq -rM '.[] | select(.ifname == "enp9s0").addr_info[0].local'                                                       │...passed.
88.198.0.164                                                                                                                               │
ns$ ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'                                                                   │Starting test: TCP/IPv4: ns to host (spliced): big transfer
88.198.0.161                                                                                                                               │? cmp /home/sbrivio/passt/test/big.bin /tmp/passt-tests-Fe5Kr9/pasta/tcp/test_big.bin
ns$ ip -j link show | jq -rM '.[] | select(.ifname == "enp9s0").mtu'                                                                       │...passed.
65520                                                                                                                                      │
ns$ /sbin/dhclient -6 --no-pid enp9s0                                                                                                      │Starting test: TCP/IPv4: ns to host (via tap): big transfer
ns$ ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "enp9s0").addr_info[] | select(.prefixlen == 128).local] | .[0]'                   │? cmp /home/sbrivio/passt/test/big.bin /tmp/passt-tests-Fe5Kr9/pasta/tcp/test_big.bin
2a01:4f8:222:904::2                                                                                                                        │...passed.
ns$ ip -j -6 route show|jq -rM '.[] | select(.dst == "default").gateway'                                                                   │
fe80::1                                                                                                                                    │Starting test: TCP/IPv4: host to ns (spliced): small transfer
ns$ which socat ip jq >/dev/null                                                                                                           │? cmp /home/sbrivio/passt/test/small.bin /tmp/passt-tests-Fe5Kr9/pasta/tcp/test_ns_small.bin
ns$ socat -u TCP4-LISTEN:10002 OPEN:/tmp/passt-tests-Fe5Kr9/pasta/tcp/test_ns_big.bin,create,trunc                                         │...passed.
ns$ socat -u OPEN:/home/sbrivio/passt/test/big.bin TCP4:127.0.0.1:10003                                                                    │
ns$ ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'                                                                   │Starting test: TCP/IPv4: ns to host (spliced): small transfer
88.198.0.161                                                                                                                               │? cmp /home/sbrivio/passt/test/small.bin /tmp/passt-tests-Fe5Kr9/pasta/tcp/test_small.bin
ns$ socat -u OPEN:/home/sbrivio/passt/test/big.bin TCP4:88.198.0.161:10003                                                                 │...passed.
ns$ socat -u TCP4-LISTEN:10002 OPEN:/tmp/passt-tests-Fe5Kr9/pasta/tcp/test_ns_small.bin,create,trunc                                       │
ns$ socat OPEN:/home/sbrivio/passt/test/small.bin TCP4:127.0.0.1:10003                                                                     │Starting test: TCP/IPv4: ns to host (via tap): small transfer
ns$ ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'                                                                   │? cmp /home/sbrivio/passt/test/small.bin /tmp/passt-tests-Fe5Kr9/pasta/tcp/test_small.bin
88.198.0.161                                                                                                                               │...passed.
ns$ socat -u OPEN:/home/sbrivio/passt/test/small.bin TCP4:88.198.0.161:10003                                                               │
ns$ socat -u TCP6-LISTEN:10002 OPEN:/tmp/passt-tests-Fe5Kr9/pasta/tcp/test_ns_big.bin,create,trunc                                         │Starting test: TCP/IPv6: host to ns (spliced): big transfer
                                                                                                                                           │
──namespace─────────────────────────────────────────────────────────────────────────────────────────────────────────────┬──────────────────┴──pasta/tcp [7/12] - TCP/IPv6: host to ns (spliced): big transfer───────────────────────────────────
host$ ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").gateway] | .[0]'                                     │    router: 88.198.0.161
fe80::1                                                                                                                 │DNS:
host$ which ip jq >/dev/null                                                                                            │    185.12.64.1
host$ ip -j -4 addr show|jq -rM '.[] | select(.ifname == "enp9s0").addr_info[0].local'                                  │    185.12.64.2
88.198.0.164                                                                                                            │    NAT to host ::1: fe80::1
host$ ip -j -4 route show|jq -rM '[.[] | select(.dst == "default").gateway] | .[0]'                                     │NDP/DHCPv6:
88.198.0.161                                                                                                            │    assign: 2a01:4f8:222:904::2
host$ ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'                                         │    router: fe80::1
enp9s0                                                                                                                  │    our link-local: fe80::1
host$ ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "enp9s0").addr_info[] | select(.scope == "global" and .depreca│DNS:
ted != true).local] | .[0]'                                                                                             │    2a01:4ff:ff00::add:2
2a01:4f8:222:904::2                                                                                                     │    2a01:4ff:ff00::add:1
host$ ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").gateway] | .[0]'                                     │NDP: received RS, sending RA
fe80::1                                                                                                                 │DHCP: offer to discover
host$ which socat ip jq >/dev/null                                                                                      │    from 06:91:e7:c0:12:b1
host$ socat -u OPEN:/home/sbrivio/passt/test/big.bin TCP4:127.0.0.1:10002                                               │DHCP: ack to request
host$ socat -u TCP4-LISTEN:10003,bind=127.0.0.1 OPEN:/tmp/passt-tests-Fe5Kr9/pasta/tcp/test_big.bin,create,trunc        │    from 06:91:e7:c0:12:b1
host$ socat -u TCP4-LISTEN:10003 OPEN:/tmp/passt-tests-Fe5Kr9/pasta/tcp/test_big.bin,create,trunc                       │DHCPv6: received SOLICIT, sending ADVERTISE
host$ socat OPEN:/home/sbrivio/passt/test/small.bin TCP4:127.0.0.1:10002                                                │DHCPv6: received REQUEST/RENEW/CONFIRM, sending REPLY
host$ socat -u TCP4-LISTEN:10003,bind=127.0.0.1 OPEN:/tmp/passt-tests-Fe5Kr9/pasta/tcp/test_small.bin,create,trunc      │NDP: received NS, sending NA
host$ socat -u TCP4-LISTEN:10003 OPEN:/tmp/passt-tests-Fe5Kr9/pasta/tcp/test_small.bin,create,trunc                     │NDP: received NS, sending NA
host$ socat -u OPEN:/home/sbrivio/passt/test/big.bin TCP6:[::1]:10002                                                   │NDP: received NS, sending NA
host$                                                                                                                   │
──host──────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴──pasta────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Testing commit: 3195dc6 udp: Update UDP checksum using an iovec array                                                                                                                             PASS: 23 | FAIL: 0 | 2024-10-02T13:53:46+00:00

--

the second one is a UDP transfer in the pasta_podman/bats test (mismatch in
received data) for which I just accidentally lost the logs... but I'll try
to reproduce that again in a bit and share them.

-- 
Stefano