Commit f1cc9466 authored by Sun Jian's avatar Sun Jian Committed by Alexei Starovoitov
Browse files

selftests/bpf: cover short IPv4/IPv6 inputs with adjust_room 



Add a selftest covering ETH_HLEN-sized IPv4/IPv6 EtherType inputs for
bpf_prog_test_run_skb().

Reuse a single zero-initialized struct ethhdr eth_hlen and set
eth_hlen.h_proto from the per-test h_proto field.

Also add a dedicated tc_adjust_room program and route the short
IPv4/IPv6 cases to it, so the selftest actually exercises the
bpf_skb_adjust_room() path from the report.

Signed-off-by: default avatarSun Jian <sun.jian.kdev@gmail.com>
Link: https://lore.kernel.org/r/20260408034623.180320-3-sun.jian.kdev@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 12bec2bd

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

+37 −3
Original line number Diff line number Diff line
@@ -10,8 +10,8 @@ void test_empty_skb(void) 
	struct empty_skb *bpf_obj = NULL;

	struct nstoken *tok = NULL;

	struct bpf_program *prog;

	struct ethhdr eth_hlen;

	char eth_hlen_pp[15];

	char eth_hlen[14];

	int veth_ifindex;

	int ipip_ifindex;

	int err;
@@ -25,7 +25,9 @@ void test_empty_skb(void) 
		int err;

		int ret;

		int lwt_egress_ret; /* expected retval at lwt/egress */

		__be16 h_proto;

		bool success_on_tc;

		bool adjust_room;

	} tests[] = {

		/* Empty packets are always rejected. */
@@ -46,6 +48,28 @@ void test_empty_skb(void) 
			.err = -EINVAL,

		},



		/* ETH_HLEN-sized packets with IPv4/IPv6 EtherType but

		 * no L3 header are rejected.

		 */

		{

			.msg = "veth short IPv4 ingress packet",

			.data_in = &eth_hlen,

			.data_size_in = sizeof(eth_hlen),

			.ifindex = &veth_ifindex,

			.err = -EINVAL,

			.h_proto = htons(ETH_P_IP),

			.adjust_room = true,

		},

		{

			.msg = "veth short IPv6 ingress packet",

			.data_in = &eth_hlen,

			.data_size_in = sizeof(eth_hlen),

			.ifindex = &veth_ifindex,

			.err = -EINVAL,

			.h_proto = htons(ETH_P_IPV6),

			.adjust_room = true,

		},



		/* ETH_HLEN-sized packets:

		 * - can not be redirected at LWT_XMIT

		 * - can be redirected at TC to non-tunneling dest
@@ -54,7 +78,7 @@ void test_empty_skb(void) 
		{

			/* __bpf_redirect_common */

			.msg = "veth ETH_HLEN packet ingress",

			.data_in = eth_hlen,

			.data_in = &eth_hlen,

			.data_size_in = sizeof(eth_hlen),

			.ifindex = &veth_ifindex,

			.ret = -ERANGE,
@@ -68,7 +92,7 @@ void test_empty_skb(void) 
			 * tc: skb->len=14 <= skb_network_offset=14

			 */

			.msg = "ipip ETH_HLEN packet ingress",

			.data_in = eth_hlen,

			.data_in = &eth_hlen,

			.data_size_in = sizeof(eth_hlen),

			.ifindex = &ipip_ifindex,

			.ret = -ERANGE,
@@ -108,17 +132,27 @@ void test_empty_skb(void) 
	SYS(out, "ip addr add 192.168.1.1/16 dev ipip0");

	ipip_ifindex = if_nametoindex("ipip0");



	memset(eth_hlen_pp, 0, sizeof(eth_hlen_pp));

	memset(&eth_hlen, 0, sizeof(eth_hlen));



	bpf_obj = empty_skb__open_and_load();

	if (!ASSERT_OK_PTR(bpf_obj, "open skeleton"))

		goto out;



	for (i = 0; i < ARRAY_SIZE(tests); i++) {

		if (tests[i].data_in == &eth_hlen)

			eth_hlen.h_proto = tests[i].h_proto;



		bpf_object__for_each_program(prog, bpf_obj->obj) {

			bool at_egress = strstr(bpf_program__name(prog), "egress") != NULL;

			bool at_tc = !strncmp(bpf_program__section_name(prog), "tc", 2);

			bool is_adjust_room = !strcmp(bpf_program__name(prog), "tc_adjust_room");

			int expected_ret;

			char buf[128];



			if (tests[i].adjust_room != is_adjust_room)

				continue;



			expected_ret = at_egress && !at_tc ? tests[i].lwt_egress_ret : tests[i].ret;



			tattr.data_in = tests[i].data_in;

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

+7 −0
Original line number Diff line number Diff line
@@ -35,3 +35,10 @@ int tc_redirect_egress(struct __sk_buff *skb) 
	ret = bpf_clone_redirect(skb, ifindex, 0);

	return 0;

}



SEC("tc")

int tc_adjust_room(struct __sk_buff *skb)

{

	ret = bpf_skb_adjust_room(skb, 4, BPF_ADJ_ROOM_NET, 0);

	return 0;

}