selftests: net: csum: Fix checksums for packets with non-zero padding

2024-09-18T17:25:15Z

[ Upstream commit e8a63d473b49011a68a748aea1c8aefa046ebacf ] Padding is not included in UDP and TCP checksums. Therefore, reduce the length of the checksummed data to include only the data in the IP payload. This fixes spurious reported checksum failures like rx: pkt: sport=33000 len=26 csum=0xc850 verify=0xf9fe pkt: bad csum Technically it is possible for there to be trailing bytes after the UDP data but before the Ethernet padding (e.g. if sizeof(ip) + sizeof(udp) + udp.len < ip.len). However, we don't generate such packets. Fixes: 91a7de85600d ("selftests/net: add csum offload test") Signed-off-by: Sean Anderson Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20240906210743.627413-1-sean.anderson@linux.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

selftests: drv-net: add checksum tests

2024-05-09T01:57:55Z

Run tools/testing/selftest/net/csum.c as part of drv-net. This binary covers multiple scenarios, based on arguments given, for both IPv4 and IPv6: - Accept UDP correct checksum - Detect UDP invalid checksum - Accept TCP correct checksum - Detect TCP invalid checksum - Transmit UDP: basic checksum offload - Transmit UDP: zero checksum conversion The test direction is reversed between receive and transmit tests, so that the NIC under test is always the local machine. In total this adds up to 12 testcases, with more to follow. For conciseness, I replaced individual functions with a function factory. Also detect hardware offload feature availability using Ethtool netlink and skip tests when either feature is off. This need may be common for offload feature tests and eventually deserving of a thin wrapper in lib.py. Missing are the PF_PACKET based send tests ('-P'). These use virtio_net_hdr to program hardware checksum offload. Which requires looking up the local MAC address and (harder) the MAC of the next hop. I'll have to give it some though how to do that robustly and where that code would belong. Tested: make -C tools/testing/selftests/ \ TARGETS="drivers/net drivers/net/hw" \ install INSTALL_PATH=/tmp/ksft cd /tmp/ksft sudo NETIF=ens4 REMOTE_TYPE=ssh \ REMOTE_ARGS="root@10.40.0.2" \ LOCAL_V4="10.40.0.1" \ REMOTE_V4="10.40.0.2" \ ./run_kselftest.sh -t drivers/net/hw:csum.py Signed-off-by: Willem de Bruijn Link: https://lore.kernel.org/r/20240507154216.501111-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski

kernel.git/tools/testing/selftests/net/lib/csum.c, branch linux-6.10.y

selftests: net: csum: Fix checksums for packets with non-zero padding

selftests: drv-net: add checksum tests