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: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20230523025618.113937-14-john.fastabend@gmail.com
This commit is contained in:
John Fastabend 2023-05-22 19:56:17 -07:00 committed by Daniel Borkmann
parent bb516f98c7
commit 80e24d2226
2 changed files with 66 additions and 13 deletions

View File

@ -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 @@ out:
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"))
return;
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)");
recvd = recv_timeout(c1, &buf, sizeof(buf), SOCK_NONBLOCK, IO_TIMEOUT_SEC);
ASSERT_EQ(recvd, sizeof(buf), "recv_timeout(c0)");
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 @@ out_close:
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);
}

View File

@ -0,0 +1,32 @@
#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";