Commit 80e24d22 authored by John Fastabend's avatar John Fastabend Committed by Daniel Borkmann
Browse files

bpf, sockmap: Test FIONREAD returns correct bytes in rx buffer with drops 



When BPF program drops pkts the sockmap logic 'eats' the packet and
updates copied_seq. In the PASS case where the sk_buff is accepted
we update copied_seq from recvmsg path so we need a new test to
handle the drop case.

Original patch series broke this resulting in

test_sockmap_skb_verdict_fionread:PASS:ioctl(FIONREAD) error 0 nsec
test_sockmap_skb_verdict_fionread:FAIL:ioctl(FIONREAD) unexpected ioctl(FIONREAD): actual 1503041772 != expected 256

After updated patch with fix.

Signed-off-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20230523025618.113937-14-john.fastabend@gmail.com
parent bb516f98

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

+34 −13
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include "test_sockmap_skb_verdict_attach.skel.h"

#include "test_sockmap_progs_query.skel.h"

#include "test_sockmap_pass_prog.skel.h"

#include "test_sockmap_drop_prog.skel.h"

#include "bpf_iter_sockmap.skel.h"



#include "sockmap_helpers.h"
@@ -410,19 +411,31 @@ static void test_sockmap_skb_verdict_shutdown(void) 
	test_sockmap_pass_prog__destroy(skel);

}



static void test_sockmap_skb_verdict_fionread(void)

static void test_sockmap_skb_verdict_fionread(bool pass_prog)

{

	int expected, zero = 0, sent, recvd, avail;

	int err, map, verdict, s, c0, c1, p0, p1;

	struct test_sockmap_pass_prog *skel;

	int zero = 0, sent, recvd, avail;

	struct test_sockmap_pass_prog *pass;

	struct test_sockmap_drop_prog *drop;

	char buf[256] = "0123456789";



	skel = test_sockmap_pass_prog__open_and_load();

	if (!ASSERT_OK_PTR(skel, "open_and_load"))

	if (pass_prog) {

		pass = test_sockmap_pass_prog__open_and_load();

		if (!ASSERT_OK_PTR(pass, "open_and_load"))

			return;

		verdict = bpf_program__fd(pass->progs.prog_skb_verdict);

		map = bpf_map__fd(pass->maps.sock_map_rx);

		expected = sizeof(buf);

	} else {

		drop = test_sockmap_drop_prog__open_and_load();

		if (!ASSERT_OK_PTR(drop, "open_and_load"))

			return;

		verdict = bpf_program__fd(drop->progs.prog_skb_verdict);

		map = bpf_map__fd(drop->maps.sock_map_rx);

		/* On drop data is consumed immediately and copied_seq inc'd */

		expected = 0;

	}



	verdict = bpf_program__fd(skel->progs.prog_skb_verdict);

	map = bpf_map__fd(skel->maps.sock_map_rx);



	err = bpf_prog_attach(verdict, map, BPF_SK_SKB_STREAM_VERDICT, 0);

	if (!ASSERT_OK(err, "bpf_prog_attach"))
@@ -443,9 +456,12 @@ static void test_sockmap_skb_verdict_fionread(void) 
	ASSERT_EQ(sent, sizeof(buf), "xsend(p0)");

	err = ioctl(c1, FIONREAD, &avail);

	ASSERT_OK(err, "ioctl(FIONREAD) error");

	ASSERT_EQ(avail, sizeof(buf), "ioctl(FIONREAD)");

	ASSERT_EQ(avail, expected, "ioctl(FIONREAD)");

	/* On DROP test there will be no data to read */

	if (pass_prog) {

		recvd = recv_timeout(c1, &buf, sizeof(buf), SOCK_NONBLOCK, IO_TIMEOUT_SEC);

		ASSERT_EQ(recvd, sizeof(buf), "recv_timeout(c0)");

	}



out_close:

	close(c0);
@@ -453,7 +469,10 @@ static void test_sockmap_skb_verdict_fionread(void) 
	close(c1);

	close(p1);

out:

	test_sockmap_pass_prog__destroy(skel);

	if (pass_prog)

		test_sockmap_pass_prog__destroy(pass);

	else

		test_sockmap_drop_prog__destroy(drop);

}



void test_sockmap_basic(void)
@@ -493,5 +512,7 @@ void test_sockmap_basic(void) 
	if (test__start_subtest("sockmap skb_verdict shutdown"))

		test_sockmap_skb_verdict_shutdown();

	if (test__start_subtest("sockmap skb_verdict fionread"))

		test_sockmap_skb_verdict_fionread();

		test_sockmap_skb_verdict_fionread(true);

	if (test__start_subtest("sockmap skb_verdict fionread on drop"))

		test_sockmap_skb_verdict_fionread(false);

}

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

0 → 100644
+32 −0
Original line number Diff line number Diff line 
#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_endian.h>



struct {

	__uint(type, BPF_MAP_TYPE_SOCKMAP);

	__uint(max_entries, 20);

	__type(key, int);

	__type(value, int);

} sock_map_rx SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_SOCKMAP);

	__uint(max_entries, 20);

	__type(key, int);

	__type(value, int);

} sock_map_tx SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_SOCKMAP);

	__uint(max_entries, 20);

	__type(key, int);

	__type(value, int);

} sock_map_msg SEC(".maps");



SEC("sk_skb")

int prog_skb_verdict(struct __sk_buff *skb)

{

	return SK_DROP;

}



char _license[] SEC("license") = "GPL";