From: Jason Xing <kernelxing@xxxxxxxxxxx> A few weeks ago, I planned to extend SO_TIMESTMAMPING feature by using tracepoint to print information (say, tstamp) so that we can transparently equip applications with this feature and require no modification in user side. Later, we discussed at netconf and agreed that we can use bpf for better extension, which is mainly suggested by John Fastabend and Willem de Bruijn. After sending the a few series in recent days, Martin KaFai Lau provided many valuable advices. Many thanks here! I post this series to see if we have a better solution to extend. My feeling is BPF is a good place to provide a way to add timestamping by administrators, without having to rebuild applications. After this series, we could step by step implement more advanced functions/flags already in SO_TIMESTAMPING feature for bpf extension. This approach mostly relies on existing SO_TIMESTAMPING feature, users only needs to pass certain flags through bpf_setsocktop() to a separate tsflags. For TX timestamps, they will be printed during generation phase. For RX timestamps, we will wait for the moment when recvmsg() is called, which isn't supported right now. In this series, I support foundamental codes for both TCP and UDP protocols. --- v3 Link: https://lore.kernel.org/all/20241012040651.95616-1-kerneljasonxing@xxxxxxxxx/ 1. support UDP proto by introducing a new generation point. 2. for OPT_ID, introducing sk_tskey_bpf_offset to compute the delta between the current socket key and bpf socket key. It is desiged for UDP, which also applies to TCP. 3. support bpf_getsockopt() 4. use cgroup static key instead. 5. add one simple bpf selftest to show how it can be used. 6. remove the rx support from v2 because the number of patches could exceed the limit of one series. V2 Link: https://lore.kernel.org/all/20241008095109.99918-1-kerneljasonxing@xxxxxxxxx/ 1. Introduce tsflag requestors so that we are able to extend more in the future. Besides, it enables TX flags for bpf extension feature separately without breaking users. It is suggested by Vadim Fedorenko. 2. introduce a static key to control the whole feature. (Willem) 3. Open the gate of bpf_setsockopt for the SO_TIMESTAMPING feature in some TX/RX cases, not all the cases. Jason Xing (14): net-timestamp: reorganize in skb_tstamp_tx_output() net-timestamp: allow two features to work parallelly net-timestamp: open gate for bpf_setsockopt/_getsockopt net-timestamp: introduce TS_SCHED_OPT_CB to generate dev xmit timestamp net-timestamp: introduce TS_SW_OPT_CB to generate driver timestamp net-timestamp: introduce TS_ACK_OPT_CB to generate tcp acked timestamp net-timestamp: add a new triggered point to set sk_tsflags_bpf in UDP layer net-timestamp: make bpf for tx timestamp work net-timestamp: add a common helper to set tskey net-timestamp: add basic support with tskey offset net-timestamp: support OPT_ID for TCP proto net-timestamp: add OPT_ID for UDP proto net-timestamp: use static key to control bpf extension bpf: add simple bpf tests in the tx path for so_timstamping feature include/net/sock.h | 14 +- include/uapi/linux/bpf.h | 18 +++ include/uapi/linux/net_tstamp.h | 7 + net/core/filter.c | 7 +- net/core/skbuff.c | 114 +++++++++++++++- net/core/sock.c | 125 ++++++++++++++---- net/ipv4/ip_output.c | 18 ++- net/ipv4/tcp.c | 19 +++ net/ipv4/udp.c | 4 +- net/ipv6/ip6_output.c | 18 ++- net/mptcp/sockopt.c | 2 +- net/socket.c | 2 +- tools/include/uapi/linux/bpf.h | 18 +++ .../bpf/prog_tests/so_timestamping.c | 98 ++++++++++++++ .../selftests/bpf/progs/so_timestamping.c | 123 +++++++++++++++++ 15 files changed, 539 insertions(+), 48 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/so_timestamping.c create mode 100644 tools/testing/selftests/bpf/progs/so_timestamping.c -- 2.37.3
