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selftests/bpf: Extend sockmap_redir to test no-redir SK_DROP/SK_PASS #5901

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selftests/bpf: Extend sockmap_redir to test no-redir SK_DROP/SK_PASS #5901

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2d34f1d
selftests/bpf: sockmap_redir: Simplify try_recv()
mmhal Sep 5, 2025
6d963fb
selftests/bpf: sockmap_redir: Fix OOB handling
mmhal Sep 5, 2025
dc71347
selftests/bpf: sockmap_redir: Rename functions
mmhal Sep 5, 2025
c5a3170
selftests/bpf: sockmap_redir: Let test specify skel's redirect_type
mmhal Sep 5, 2025
fbb6e87
selftests/bpf: sockmap_redir: Support no-redirect SK_DROP/SK_PASS
mmhal Sep 5, 2025
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143 changes: 105 additions & 38 deletions tools/testing/selftests/bpf/prog_tests/sockmap_redir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,10 @@
* AF_UNIX, SOCK_DGRAM
* AF_VSOCK, SOCK_STREAM
* AF_VSOCK, SOCK_SEQPACKET
* x
* SK_REDIRECT
* SK_DROP
* SK_PASS
*/

#include <errno.h>
Expand Down Expand Up @@ -65,6 +69,10 @@
*/
#define UNSUPPORTED_RACY_VERD _BITUL(1)

/* Mark for an immediate SK_DROP/SK_PASS, i.e. BPF program will not redirect.
*/
#define NO_REDIRECT _BITUL(2)

enum prog_type {
SK_MSG_EGRESS,
SK_MSG_INGRESS,
Expand Down Expand Up @@ -144,21 +152,19 @@ static void get_redir_params(struct redir_spec *redir,
*redirect_flags = 0;
}

static void try_recv(const char *prefix, int fd, int flags, bool expect_success)
static void fail_recv(const char *prefix, int fd, int more_flags)
{
ssize_t n;
char buf;

errno = 0;
n = recv(fd, &buf, 1, flags);
if (n < 0 && expect_success)
FAIL_ERRNO("%s: unexpected failure: retval=%zd", prefix, n);
if (!n && !expect_success)
FAIL("%s: expected failure: retval=%zd", prefix, n);
n = recv(fd, &buf, 1, MSG_DONTWAIT | more_flags);
if (n >= 0)
FAIL("%s: unexpected success: retval=%zd", prefix, n);
}

static void handle_unsupported(int sd_send, int sd_peer, int sd_in, int sd_out,
int sd_recv, int map_verd, int status)
static void handle_unsupported(int sd_send, int send_flags, int sd_peer,
int sd_in, int sd_out, int sd_recv,
int map_verd, int status)
{
unsigned int drop, pass;
char recv_buf;
Expand All @@ -174,7 +180,7 @@ static void handle_unsupported(int sd_send, int sd_peer, int sd_in, int sd_out,
goto get_verdict;
}

if (pass != 0) {
if (pass && !(status & NO_REDIRECT)) {
FAIL("unsupported: wanted verdict pass 0, have %u", pass);
return;
}
Expand All @@ -187,19 +193,34 @@ static void handle_unsupported(int sd_send, int sd_peer, int sd_in, int sd_out,
FAIL_ERRNO("unsupported: packet missing, retval=%zd", n);
}

/* af_unix send("ab", MSG_OOB) spits out 2 packets, but only the latter
* ("b") is designated OOB. If the peer is in a sockmap, the OOB packet
* will be silently dropped. Otherwise OOB stays in the queue and should
* be taken care of.
*/
if ((send_flags & MSG_OOB) && !pass && !drop) {
errno = 0;
n = recv_timeout(sd_peer, &recv_buf, 1, MSG_OOB, IO_TIMEOUT_SEC);
/* Ignore unsupported sk_msg error */
if (n != 1 && errno != EOPNOTSUPP)
FAIL_ERRNO("recv(OOB): retval=%zd", n);
}

/* Ensure queues are empty */
try_recv("bpf.recv(sd_send)", sd_send, MSG_DONTWAIT, false);
fail_recv("bpf.recv(sd_send)", sd_send, 0);
if (sd_in != sd_send)
try_recv("bpf.recv(sd_in)", sd_in, MSG_DONTWAIT, false);
fail_recv("bpf.recv(sd_in)", sd_in, 0);

try_recv("bpf.recv(sd_out)", sd_out, MSG_DONTWAIT, false);
fail_recv("bpf.recv(sd_out)", sd_out, 0);
if (sd_recv != sd_out)
try_recv("bpf.recv(sd_recv)", sd_recv, MSG_DONTWAIT, false);
fail_recv("bpf.recv(sd_recv)", sd_recv, 0);

fail_recv("recv(sd_peer, OOB)", sd_peer, MSG_OOB);
fail_recv("recv(sd_out, OOB)", sd_out, MSG_OOB);
}

static void test_send_redir_recv(int sd_send, int send_flags, int sd_peer,
int sd_in, int sd_out, int sd_recv,
struct maps *maps, int status)
static void test_send_recv(int sd_send, int send_flags, int sd_peer, int sd_in,
int sd_out, int sd_recv, struct maps *maps, int status)
{
unsigned int drop, pass;
char *send_buf = "ab";
Expand All @@ -225,14 +246,14 @@ static void test_send_redir_recv(int sd_send, int send_flags, int sd_peer,
FAIL("incomplete send");
if (n < 0) {
/* sk_msg redirect combo not supported? */
if (status & SUPPORTED || errno != EACCES)
if (errno != EACCES)
FAIL_ERRNO("send");
goto out;
}

if (!(status & SUPPORTED)) {
handle_unsupported(sd_send, sd_peer, sd_in, sd_out, sd_recv,
maps->verd, status);
if (!(status & SUPPORTED) || (status & NO_REDIRECT)) {
handle_unsupported(sd_send, send_flags, sd_peer, sd_in, sd_out,
sd_recv, maps->verd, status);
goto out;
}

Expand All @@ -257,15 +278,13 @@ static void test_send_redir_recv(int sd_send, int send_flags, int sd_peer,

if (send_flags & MSG_OOB) {
/* Fail reading OOB while in sockmap */
try_recv("bpf.recv(sd_out, MSG_OOB)", sd_out,
MSG_OOB | MSG_DONTWAIT, false);
fail_recv("bpf.recv(sd_out, MSG_OOB)", sd_out, MSG_OOB);

/* Remove sd_out from sockmap */
xbpf_map_delete_elem(maps->out, &u32(0));

/* Check that OOB was dropped on redirect */
try_recv("recv(sd_out, MSG_OOB)", sd_out,
MSG_OOB | MSG_DONTWAIT, false);
fail_recv("recv(sd_out, MSG_OOB)", sd_out, MSG_OOB);

goto del_in;
}
Expand Down Expand Up @@ -316,17 +335,18 @@ static int is_redir_supported(enum prog_type type, const char *in,
static int get_support_status(enum prog_type type, const char *in,
const char *out)
{
int status = is_redir_supported(type, in, out);
int status = in ? is_redir_supported(type, in, out) : 0;

if (type == SK_SKB_INGRESS && strstarts(out, "v_"))
if ((type == SK_SKB_INGRESS || type == SK_SKB_EGRESS) &&
strstarts(out, "v_"))
status |= UNSUPPORTED_RACY_VERD;

return status;
}

static void test_socket(enum bpf_map_type type, struct redir_spec *redir,
struct maps *maps, struct socket_spec *s_in,
struct socket_spec *s_out)
static void test_redir(enum bpf_map_type type, struct redir_spec *redir,
struct maps *maps, struct socket_spec *s_in,
struct socket_spec *s_out)
{
int fd_in, fd_out, fd_send, fd_peer, fd_recv, flags, status;
const char *in_str, *out_str;
Expand Down Expand Up @@ -356,12 +376,47 @@ static void test_socket(enum bpf_map_type type, struct redir_spec *redir,
if (!test__start_subtest(s))
return;

test_send_redir_recv(fd_send, flags, fd_peer, fd_in, fd_out, fd_recv,
maps, status);
test_send_recv(fd_send, flags, fd_peer, fd_in, fd_out, fd_recv, maps,
status);
}

static void test_redir(enum bpf_map_type type, struct redir_spec *redir,
struct maps *maps)
static void test_verdict(enum bpf_map_type type, struct redir_spec *redir,
struct maps *maps, struct socket_spec *s_in,
enum sk_action action)
{
int fd_in, fd_out, fd_send, fd_peer, fd_recv, flags, status;
char s[MAX_TEST_NAME];
const char *s_str;

fd_in = s_in->in[0];
fd_out = s_in->in[1];
fd_send = s_in->in[redir->idx_send];
fd_peer = s_in->in[redir->idx_send ^ 1];
fd_recv = s_in->in[redir->idx_send ^ 1];
flags = s_in->send_flags;

s_str = socket_kind_to_str(fd_in);
status = get_support_status(redir->prog_type, NULL, s_str);
status |= NO_REDIRECT;

snprintf(s, sizeof(s),
"%-4s %-17s %-7s %-5s%6s",
/* hash sk_skb-to-ingress u_str pass (OOB) */
type == BPF_MAP_TYPE_SOCKMAP ? "map" : "hash",
redir->name,
s_str,
action == SK_PASS ? "pass" : "drop",
flags & MSG_OOB ? "(OOB)" : "");

if (!test__start_subtest(s))
return;

test_send_recv(fd_send, flags, fd_peer, fd_in, fd_out, fd_recv, maps,
status);
}

static void test_sockets(enum bpf_map_type type, struct redir_spec *redir,
struct maps *maps, int *skel_redir_type)
{
struct socket_spec *s, sockets[] = {
{ AF_INET, SOCK_STREAM },
Expand All @@ -382,9 +437,11 @@ static void test_redir(enum bpf_map_type type, struct redir_spec *redir,
if (socket_spec_pairs(s))
goto out;

*skel_redir_type = type;

/* Intra-proto */
for (s = sockets; s < sockets + ARRAY_SIZE(sockets); s++)
test_socket(type, redir, maps, s, s);
test_redir(type, redir, maps, s, s);

/* Cross-proto */
for (int i = 0; i < ARRAY_SIZE(sockets); i++) {
Expand All @@ -398,9 +455,20 @@ static void test_redir(enum bpf_map_type type, struct redir_spec *redir,
in->sotype == out->sotype))
continue;

test_socket(type, redir, maps, in, out);
test_redir(type, redir, maps, in, out);
}
}

/* No redirect: SK_DROP */
*skel_redir_type = __MAX_BPF_MAP_TYPE + SK_DROP;
for (s = sockets; s < sockets + ARRAY_SIZE(sockets); s++)
test_verdict(type, redir, maps, s, SK_DROP);

/* No redirect: SK_PASS */
*skel_redir_type = __MAX_BPF_MAP_TYPE + SK_PASS;
for (s = sockets; s < sockets + ARRAY_SIZE(sockets); s++)
test_verdict(type, redir, maps, s, SK_PASS);

out:
while (--s >= sockets)
socket_spec_close(s);
Expand Down Expand Up @@ -441,15 +509,14 @@ static void test_map(enum bpf_map_type type)
return;
}

skel->bss->redirect_type = type;
maps.verd = bpf_map__fd(skel->maps.verdict_map);
get_redir_params(r, skel, &prog_fd, &attach_type,
&skel->bss->redirect_flags);

if (xbpf_prog_attach(prog_fd, maps.in, attach_type, 0))
return;

test_redir(type, r, &maps);
test_sockets(type, r, &maps, &skel->bss->redirect_type);

if (xbpf_prog_detach2(prog_fd, maps.in, attach_type))
return;
Expand Down
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