From 9fa02892857ae2b3b699630e5ede28f72106e7e7 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 21 Feb 2023 10:05:18 -0800 Subject: [PATCH] selftests/bpf: Fix BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL for empty flow label Kernel's flow dissector continues to parse the packet when the (optional) IPv6 flow label is empty even when instructed to stop (via BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL). Do the same in our reference BPF reimplementation. Signed-off-by: Stanislav Fomichev Acked-by: Willem de Bruijn Link: https://lore.kernel.org/r/20230221180518.2139026-1-sdf@google.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/flow_dissector.c | 24 +++++++++++++++++++ tools/testing/selftests/bpf/progs/bpf_flow.c | 2 +- 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c index 7acca37a3d2b5..c4773173a4e43 100644 --- a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c +++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c @@ -345,6 +345,30 @@ struct test tests[] = { .flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL, .retval = BPF_OK, }, + { + .name = "ipv6-empty-flow-label", + .pkt.ipv6 = { + .eth.h_proto = __bpf_constant_htons(ETH_P_IPV6), + .iph.nexthdr = IPPROTO_TCP, + .iph.payload_len = __bpf_constant_htons(MAGIC_BYTES), + .iph.flow_lbl = { 0x00, 0x00, 0x00 }, + .tcp.doff = 5, + .tcp.source = 80, + .tcp.dest = 8080, + }, + .keys = { + .flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL, + .nhoff = ETH_HLEN, + .thoff = ETH_HLEN + sizeof(struct ipv6hdr), + .addr_proto = ETH_P_IPV6, + .ip_proto = IPPROTO_TCP, + .n_proto = __bpf_constant_htons(ETH_P_IPV6), + .sport = 80, + .dport = 8080, + }, + .flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL, + .retval = BPF_OK, + }, { .name = "ipip-encap", .pkt.ipip = { diff --git a/tools/testing/selftests/bpf/progs/bpf_flow.c b/tools/testing/selftests/bpf/progs/bpf_flow.c index a20c5ed5e4546..b04e092fac947 100644 --- a/tools/testing/selftests/bpf/progs/bpf_flow.c +++ b/tools/testing/selftests/bpf/progs/bpf_flow.c @@ -337,7 +337,7 @@ PROG(IPV6)(struct __sk_buff *skb) keys->ip_proto = ip6h->nexthdr; keys->flow_label = ip6_flowlabel(ip6h); - if (keys->flags & BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) + if (keys->flow_label && keys->flags & BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) return export_flow_keys(keys, BPF_OK); return parse_ipv6_proto(skb, ip6h->nexthdr); -- 2.30.2