From d6513727c2af39a8cffb0d9b07376e51a85f347f Mon Sep 17 00:00:00 2001 From: Shmulik Ladkani Date: Sun, 21 Aug 2022 14:35:19 +0300 Subject: bpf, selftests: Test BPF_FLOW_DISSECTOR_CONTINUE The dissector program returns BPF_FLOW_DISSECTOR_CONTINUE (and avoids setting skb->flow_keys or last_dissection map) in case it encounters IP packets whose (outer) source address is 127.0.0.127. Additional test is added to prog_tests/flow_dissector.c which sets this address as test's pkk.iph.saddr, with the expected retval of BPF_FLOW_DISSECTOR_CONTINUE. Also, legacy test_flow_dissector.sh was similarly augmented. Signed-off-by: Shmulik Ladkani Signed-off-by: Daniel Borkmann Reviewed-by: Stanislav Fomichev Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20220821113519.116765-5-shmulik.ladkani@gmail.com --- tools/testing/selftests/bpf/progs/bpf_flow.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'tools/testing/selftests/bpf/progs/bpf_flow.c') diff --git a/tools/testing/selftests/bpf/progs/bpf_flow.c b/tools/testing/selftests/bpf/progs/bpf_flow.c index f266c757b3df..a20c5ed5e454 100644 --- a/tools/testing/selftests/bpf/progs/bpf_flow.c +++ b/tools/testing/selftests/bpf/progs/bpf_flow.c @@ -22,6 +22,8 @@ #define PROG(F) PROG_(F, _##F) #define PROG_(NUM, NAME) SEC("flow_dissector") int flow_dissector_##NUM +#define FLOW_CONTINUE_SADDR 0x7f00007f /* 127.0.0.127 */ + /* These are the identifiers of the BPF programs that will be used in tail * calls. Name is limited to 16 characters, with the terminating character and * bpf_func_ above, we have only 6 to work with, anything after will be cropped. @@ -143,6 +145,19 @@ int _dissect(struct __sk_buff *skb) { struct bpf_flow_keys *keys = skb->flow_keys; + if (keys->n_proto == bpf_htons(ETH_P_IP)) { + /* IP traffic from FLOW_CONTINUE_SADDR falls-back to + * standard dissector + */ + struct iphdr *iph, _iph; + + iph = bpf_flow_dissect_get_header(skb, sizeof(*iph), &_iph); + if (iph && iph->ihl == 5 && + iph->saddr == bpf_htonl(FLOW_CONTINUE_SADDR)) { + return BPF_FLOW_DISSECTOR_CONTINUE; + } + } + return parse_eth_proto(skb, keys->n_proto); } -- cgit