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selftests: bpf: Convert sk_lookup ctx access tests to PROG_TEST_RUN
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Convert the selftests for sk_lookup narrow context access to use
PROG_TEST_RUN instead of creating actual sockets. This ensures that
ctx is populated correctly when using PROG_TEST_RUN.

Assert concrete values since we now control remote_ip and remote_port.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210303101816.36774-4-lmb@cloudflare.com
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Lorenz Bauer authored and Alexei Starovoitov committed Mar 5, 2021
1 parent 7c32e8f commit 509b293
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Showing 2 changed files with 109 additions and 36 deletions.
83 changes: 68 additions & 15 deletions tools/testing/selftests/bpf/prog_tests/sk_lookup.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -241,6 +241,48 @@ static int make_client(int sotype, const char *ip, int port)
return -1;
}

static __u64 socket_cookie(int fd)
{
__u64 cookie;
socklen_t cookie_len = sizeof(cookie);

if (CHECK(getsockopt(fd, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len) < 0,
"getsockopt(SO_COOKIE)", "%s\n", strerror(errno)))
return 0;
return cookie;
}

static int fill_sk_lookup_ctx(struct bpf_sk_lookup *ctx, const char *local_ip, __u16 local_port,
const char *remote_ip, __u16 remote_port)
{
void *local, *remote;
int err;

memset(ctx, 0, sizeof(*ctx));
ctx->local_port = local_port;
ctx->remote_port = htons(remote_port);

if (is_ipv6(local_ip)) {
ctx->family = AF_INET6;
local = &ctx->local_ip6[0];
remote = &ctx->remote_ip6[0];
} else {
ctx->family = AF_INET;
local = &ctx->local_ip4;
remote = &ctx->remote_ip4;
}

err = inet_pton(ctx->family, local_ip, local);
if (CHECK(err != 1, "inet_pton", "local_ip failed\n"))
return 1;

err = inet_pton(ctx->family, remote_ip, remote);
if (CHECK(err != 1, "inet_pton", "remote_ip failed\n"))
return 1;

return 0;
}

static int send_byte(int fd)
{
ssize_t n;
Expand Down Expand Up @@ -1009,18 +1051,27 @@ static void test_drop_on_reuseport(struct test_sk_lookup *skel)

static void run_sk_assign(struct test_sk_lookup *skel,
struct bpf_program *lookup_prog,
const char *listen_ip, const char *connect_ip)
const char *remote_ip, const char *local_ip)
{
int client_fd, peer_fd, server_fds[MAX_SERVERS] = { -1 };
struct bpf_link *lookup_link;
int server_fds[MAX_SERVERS] = { -1 };
struct bpf_sk_lookup ctx;
__u64 server_cookie;
int i, err;

lookup_link = attach_lookup_prog(lookup_prog);
if (!lookup_link)
DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
.ctx_in = &ctx,
.ctx_size_in = sizeof(ctx),
.ctx_out = &ctx,
.ctx_size_out = sizeof(ctx),
);

if (fill_sk_lookup_ctx(&ctx, local_ip, EXT_PORT, remote_ip, INT_PORT))
return;

ctx.protocol = IPPROTO_TCP;

for (i = 0; i < ARRAY_SIZE(server_fds); i++) {
server_fds[i] = make_server(SOCK_STREAM, listen_ip, 0, NULL);
server_fds[i] = make_server(SOCK_STREAM, local_ip, 0, NULL);
if (server_fds[i] < 0)
goto close_servers;

Expand All @@ -1030,23 +1081,25 @@ static void run_sk_assign(struct test_sk_lookup *skel,
goto close_servers;
}

client_fd = make_client(SOCK_STREAM, connect_ip, EXT_PORT);
if (client_fd < 0)
server_cookie = socket_cookie(server_fds[SERVER_B]);
if (!server_cookie)
return;

err = bpf_prog_test_run_opts(bpf_program__fd(lookup_prog), &opts);
if (CHECK(err, "test_run", "failed with error %d\n", errno))
goto close_servers;

if (CHECK(ctx.cookie == 0, "ctx.cookie", "no socket selected\n"))
goto close_servers;

peer_fd = accept(server_fds[SERVER_B], NULL, NULL);
if (CHECK(peer_fd < 0, "accept", "failed\n"))
goto close_client;
CHECK(ctx.cookie != server_cookie, "ctx.cookie",
"selected sk %llu instead of %llu\n", ctx.cookie, server_cookie);

close(peer_fd);
close_client:
close(client_fd);
close_servers:
for (i = 0; i < ARRAY_SIZE(server_fds); i++) {
if (server_fds[i] != -1)
close(server_fds[i]);
}
bpf_link__destroy(lookup_link);
}

static void run_sk_assign_v4(struct test_sk_lookup *skel,
Expand Down
62 changes: 41 additions & 21 deletions tools/testing/selftests/bpf/progs/test_sk_lookup.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,10 @@ static const int PROG_DONE = 1;
static const __u32 KEY_SERVER_A = SERVER_A;
static const __u32 KEY_SERVER_B = SERVER_B;

static const __u16 SRC_PORT = bpf_htons(8008);
static const __u32 SRC_IP4 = IP4(127, 0, 0, 2);
static const __u32 SRC_IP6[] = IP6(0xfd000000, 0x0, 0x0, 0x00000002);

static const __u16 DST_PORT = 7007; /* Host byte order */
static const __u32 DST_IP4 = IP4(127, 0, 0, 1);
static const __u32 DST_IP6[] = IP6(0xfd000000, 0x0, 0x0, 0x00000001);
Expand Down Expand Up @@ -398,11 +402,12 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx)
if (LSW(ctx->protocol, 0) != IPPROTO_TCP)
return SK_DROP;

/* Narrow loads from remote_port field. Expect non-0 value. */
if (LSB(ctx->remote_port, 0) == 0 && LSB(ctx->remote_port, 1) == 0 &&
LSB(ctx->remote_port, 2) == 0 && LSB(ctx->remote_port, 3) == 0)
/* Narrow loads from remote_port field. Expect SRC_PORT. */
if (LSB(ctx->remote_port, 0) != ((SRC_PORT >> 0) & 0xff) ||
LSB(ctx->remote_port, 1) != ((SRC_PORT >> 8) & 0xff) ||
LSB(ctx->remote_port, 2) != 0 || LSB(ctx->remote_port, 3) != 0)
return SK_DROP;
if (LSW(ctx->remote_port, 0) == 0)
if (LSW(ctx->remote_port, 0) != SRC_PORT)
return SK_DROP;

/* Narrow loads from local_port field. Expect DST_PORT. */
Expand All @@ -415,11 +420,14 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx)

/* Narrow loads from IPv4 fields */
if (v4) {
/* Expect non-0.0.0.0 in remote_ip4 */
if (LSB(ctx->remote_ip4, 0) == 0 && LSB(ctx->remote_ip4, 1) == 0 &&
LSB(ctx->remote_ip4, 2) == 0 && LSB(ctx->remote_ip4, 3) == 0)
/* Expect SRC_IP4 in remote_ip4 */
if (LSB(ctx->remote_ip4, 0) != ((SRC_IP4 >> 0) & 0xff) ||
LSB(ctx->remote_ip4, 1) != ((SRC_IP4 >> 8) & 0xff) ||
LSB(ctx->remote_ip4, 2) != ((SRC_IP4 >> 16) & 0xff) ||
LSB(ctx->remote_ip4, 3) != ((SRC_IP4 >> 24) & 0xff))
return SK_DROP;
if (LSW(ctx->remote_ip4, 0) == 0 && LSW(ctx->remote_ip4, 1) == 0)
if (LSW(ctx->remote_ip4, 0) != ((SRC_IP4 >> 0) & 0xffff) ||
LSW(ctx->remote_ip4, 1) != ((SRC_IP4 >> 16) & 0xffff))
return SK_DROP;

/* Expect DST_IP4 in local_ip4 */
Expand Down Expand Up @@ -448,20 +456,32 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx)

/* Narrow loads from IPv6 fields */
if (!v4) {
/* Expect non-:: IP in remote_ip6 */
if (LSB(ctx->remote_ip6[0], 0) == 0 && LSB(ctx->remote_ip6[0], 1) == 0 &&
LSB(ctx->remote_ip6[0], 2) == 0 && LSB(ctx->remote_ip6[0], 3) == 0 &&
LSB(ctx->remote_ip6[1], 0) == 0 && LSB(ctx->remote_ip6[1], 1) == 0 &&
LSB(ctx->remote_ip6[1], 2) == 0 && LSB(ctx->remote_ip6[1], 3) == 0 &&
LSB(ctx->remote_ip6[2], 0) == 0 && LSB(ctx->remote_ip6[2], 1) == 0 &&
LSB(ctx->remote_ip6[2], 2) == 0 && LSB(ctx->remote_ip6[2], 3) == 0 &&
LSB(ctx->remote_ip6[3], 0) == 0 && LSB(ctx->remote_ip6[3], 1) == 0 &&
LSB(ctx->remote_ip6[3], 2) == 0 && LSB(ctx->remote_ip6[3], 3) == 0)
/* Expect SRC_IP6 in remote_ip6 */
if (LSB(ctx->remote_ip6[0], 0) != ((SRC_IP6[0] >> 0) & 0xff) ||
LSB(ctx->remote_ip6[0], 1) != ((SRC_IP6[0] >> 8) & 0xff) ||
LSB(ctx->remote_ip6[0], 2) != ((SRC_IP6[0] >> 16) & 0xff) ||
LSB(ctx->remote_ip6[0], 3) != ((SRC_IP6[0] >> 24) & 0xff) ||
LSB(ctx->remote_ip6[1], 0) != ((SRC_IP6[1] >> 0) & 0xff) ||
LSB(ctx->remote_ip6[1], 1) != ((SRC_IP6[1] >> 8) & 0xff) ||
LSB(ctx->remote_ip6[1], 2) != ((SRC_IP6[1] >> 16) & 0xff) ||
LSB(ctx->remote_ip6[1], 3) != ((SRC_IP6[1] >> 24) & 0xff) ||
LSB(ctx->remote_ip6[2], 0) != ((SRC_IP6[2] >> 0) & 0xff) ||
LSB(ctx->remote_ip6[2], 1) != ((SRC_IP6[2] >> 8) & 0xff) ||
LSB(ctx->remote_ip6[2], 2) != ((SRC_IP6[2] >> 16) & 0xff) ||
LSB(ctx->remote_ip6[2], 3) != ((SRC_IP6[2] >> 24) & 0xff) ||
LSB(ctx->remote_ip6[3], 0) != ((SRC_IP6[3] >> 0) & 0xff) ||
LSB(ctx->remote_ip6[3], 1) != ((SRC_IP6[3] >> 8) & 0xff) ||
LSB(ctx->remote_ip6[3], 2) != ((SRC_IP6[3] >> 16) & 0xff) ||
LSB(ctx->remote_ip6[3], 3) != ((SRC_IP6[3] >> 24) & 0xff))
return SK_DROP;
if (LSW(ctx->remote_ip6[0], 0) == 0 && LSW(ctx->remote_ip6[0], 1) == 0 &&
LSW(ctx->remote_ip6[1], 0) == 0 && LSW(ctx->remote_ip6[1], 1) == 0 &&
LSW(ctx->remote_ip6[2], 0) == 0 && LSW(ctx->remote_ip6[2], 1) == 0 &&
LSW(ctx->remote_ip6[3], 0) == 0 && LSW(ctx->remote_ip6[3], 1) == 0)
if (LSW(ctx->remote_ip6[0], 0) != ((SRC_IP6[0] >> 0) & 0xffff) ||
LSW(ctx->remote_ip6[0], 1) != ((SRC_IP6[0] >> 16) & 0xffff) ||
LSW(ctx->remote_ip6[1], 0) != ((SRC_IP6[1] >> 0) & 0xffff) ||
LSW(ctx->remote_ip6[1], 1) != ((SRC_IP6[1] >> 16) & 0xffff) ||
LSW(ctx->remote_ip6[2], 0) != ((SRC_IP6[2] >> 0) & 0xffff) ||
LSW(ctx->remote_ip6[2], 1) != ((SRC_IP6[2] >> 16) & 0xffff) ||
LSW(ctx->remote_ip6[3], 0) != ((SRC_IP6[3] >> 0) & 0xffff) ||
LSW(ctx->remote_ip6[3], 1) != ((SRC_IP6[3] >> 16) & 0xffff))
return SK_DROP;
/* Expect DST_IP6 in local_ip6 */
if (LSB(ctx->local_ip6[0], 0) != ((DST_IP6[0] >> 0) & 0xff) ||
Expand Down

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