kernel/tools/testing/selftests/net/udpgso.c, branch linux-rolling-stable

udp: gso: do not drop small packets when PMTU reduces

2025-02-17T09:05:00Z

[ Upstream commit 235174b2bed88501fda689c113c55737f99332d8 ] Commit 4094871db1d6 ("udp: only do GSO if # of segs > 1") avoided GSO for small packets. But the kernel currently dismisses GSO requests only after checking MTU/PMTU on gso_size. This means any packets, regardless of their payload sizes, could be dropped when PMTU becomes smaller than requested gso_size. We encountered this issue in production and it caused a reliability problem that new QUIC connection cannot be established before PMTU cache expired, while non GSO sockets still worked fine at the same time. Ideally, do not check any GSO related constraints when payload size is smaller than requested gso_size, and return EMSGSIZE instead of EINVAL on MTU/PMTU check failure to be more specific on the error cause. Fixes: 4094871db1d6 ("udp: only do GSO if # of segs > 1") Signed-off-by: Yan Zhai Suggested-by: Willem de Bruijn Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

selftests/net: Add coverage for UDP GSO with IPv6 extension headers

2024-08-10T04:58:08Z

After enabling UDP GSO for devices not offering checksum offload, we have hit a regression where a bad offload warning can be triggered when sending a datagram with IPv6 extension headers. Extend the UDP GSO IPv6 tests to cover this scenario. Reviewed-by: Willem de Bruijn Signed-off-by: Jakub Sitnicki Link: https://patch.msgid.link/20240808-udp-gso-egress-from-tunnel-v4-3-f5c5b4149ab9@cloudflare.com Signed-off-by: Jakub Kicinski

selftests/net: Add test coverage for UDP GSO software fallback

2024-06-29T01:13:00Z

Extend the existing test to exercise UDP GSO egress through devices with various offload capabilities, including lack of checksum offload, which is the default case for TUN/TAP devices. Test against a dummy device because it is simpler to set up then TUN/TAP. Signed-off-by: Jakub Sitnicki Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20240626-linux-udpgso-v2-2-422dfcbd6b48@cloudflare.com Signed-off-by: Jakub Kicinski

net: change maximum number of UDP segments to 128

2024-04-14T16:05:08Z

The commit fc8b2a619469 ("net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation") adds check of potential number of UDP segments vs UDP_MAX_SEGMENTS in linux/virtio_net.h. After this change certification test of USO guest-to-guest transmit on Windows driver for virtio-net device fails, for example with packet size of ~64K and mss of 536 bytes. In general the USO should not be more restrictive than TSO. Indeed, in case of unreasonably small mss a lot of segments can cause queue overflow and packet loss on the destination. Limit of 128 segments is good for any practical purpose, with minimal meaningful mss of 536 the maximal UDP packet will be divided to ~120 segments. The number of segments for UDP packets is validated vs UDP_MAX_SEGMENTS also in udp.c (v4,v6), this does not affect quest-to-guest path but does affect packets sent to host, for example. It is important to mention that UDP_MAX_SEGMENTS is kernel-only define and not available to user mode socket applications. In order to request MSS smaller than MTU the applications just uses setsockopt with SOL_UDP and UDP_SEGMENT and there is no limitations on socket API level. Fixes: fc8b2a619469 ("net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation") Signed-off-by: Yuri Benditovich Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

selftests: udpgso: Pull up network setup into shell script

2024-02-09T20:56:49Z

udpgso regression test configures routing and device MTU directly through uAPI (Netlink, ioctl) to do its job. While there is nothing wrong with it, it takes more effort than doing it from shell. Looking forward, we would like to extend the udpgso regression tests to cover the EIO corner case [1], once it gets addressed. That will require a dummy device and device feature manipulation to set it up. Which means more Netlink code. So, in preparation, pull out network configuration into the shell script part of the test, so it is easily extendable in the future. Also, because it now easy to setup routing, add a second local IPv6 address. Because the second address is not managed by the kernel, we can "replace" the corresponding local route with a reduced-MTU one. This unblocks the disabled "ipv6 connected" test case. Add a similar setup for IPv4 for symmetry. [1] https://lore.kernel.org/netdev/87jzqsld6q.fsf@cloudflare.com/ Reviewed-by: Willem de Bruijn Signed-off-by: Jakub Sitnicki Link: https://lore.kernel.org/r/20240207-jakub-krn-635-v3-1-3dfa3da8a7d3@cloudflare.com Signed-off-by: Jakub Kicinski

selftests: Calculate udpgso segment count without header adjustment

2021-12-24T03:20:06Z

The below referenced commit correctly updated the computation of number of segments (gso_size) by using only the gso payload size and removing the header lengths. With this change the regression test started failing. Update the tests to match this new behavior. Both IPv4 and IPv6 tests are updated, as a separate patch in this series will update udp_v6_send_skb to match this change in udp_send_skb. Fixes: 158390e45612 ("udp: using datalen to cap max gso segments") Signed-off-by: Coco Li Reviewed-by: Willem de Bruijn Link: https://lore.kernel.org/r/20211223222441.2975883-2-lixiaoyan@google.com Signed-off-by: Jakub Kicinski

Merge tag 'linux-kselftest-5.5-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2019-11-25T22:58:09Z

Pull kselftest fixes from Shuah Khan: "This consists of several fixes to tests and framework. Masami Hiramatsu fixed several tests to build and run correctly on arm and other 32bit architectures" * tag 'linux-kselftest-5.5-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: selftests: sync: Fix cast warnings on arm selftests: net: Fix printf format warnings on arm selftests: net: Use size_t and ssize_t for counting file size selftests: vm: Build/Run 64bit tests only on 64bit arch selftests: proc: Make va_max 1MB kselftest: Fix NULL INSTALL_PATH for TARGETS runlist selftests: Move kselftest_module.sh into kselftest/ selftests: gen_kselftest_tar.sh: Do not clobber kselftest/ selftests: breakpoints: Fix a typo of function name selftests: Fix O= and KBUILD_OUTPUT handling for relative paths

selftests: net: Fix printf format warnings on arm

2019-11-07T21:54:08Z

Fix printf format warnings on arm (and other 32bit arch). - udpgso.c and udpgso_bench_tx use %lu for size_t but it should be unsigned long long on 32bit arch. - so_txtime.c uses %ld for int64_t, but it should be unsigned long long on 32bit arch. Signed-off-by: Masami Hiramatsu Cc: Willem de Bruijn Cc: David S. Miller Signed-off-by: Shuah Khan

udp: only do GSO if # of segs > 1

2019-10-03T15:47:10Z

Prior to this change an application sending <= 1MSS worth of data and enabling UDP GSO would fail if the system had SW GSO enabled, but the same send would succeed if HW GSO offload is enabled. In addition to this inconsistency the error in the SW GSO case does not get back to the application if sending out of a real device so the user is unaware of this failure. With this change we only perform GSO if the # of segments is > 1 even if the application has enabled segmentation. I've also updated the relevant udpgso selftests. Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT") Signed-off-by: Josh Hunt Reviewed-by: Willem de Bruijn Reviewed-by: Alexander Duyck Signed-off-by: David S. Miller

selftest/net: Remove duplicate header

2019-03-04T19:35:51Z

Remove duplicate header which is included twice. Signed-off-by: Sabyasachi Gupta Signed-off-by: Souptick Joarder Signed-off-by: David S. Miller