Commit 9fa02892 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Alexei Starovoitov
Browse files

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: default avatarStanislav Fomichev <sdf@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230221180518.2139026-1-sdf@google.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent d40c3847

tools/testing/selftests/bpf/prog_tests/flow_dissector.c

+24 −0
Original line number Diff line number Diff line
@@ -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 = {

tools/testing/selftests/bpf/progs/bpf_flow.c

+1 −1
Original line number Diff line number Diff line
@@ -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);