[PATCH bpf v9 5/5] selftests/bpf: add strparser test for bpf

Jiayuan Chen
2025-01-22T10:13:21Z

Add test cases for bpf + strparser and separated them from
sockmap_basic, as strparser has more encapsulation and parsing
capabilities compared to standard sockmap.

Signed-off-by: Jiayuan Chen <mrpre@163.com>
---
.../selftests/bpf/prog_tests/sockmap_basic.c | 53 --
.../selftests/bpf/prog_tests/sockmap_strp.c | 454 ++++++++++++++++++
.../selftests/bpf/progs/test_sockmap_strp.c | 53 ++
3 files changed, 507 insertions(+), 53 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/sockmap_strp.c
create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_strp.c

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
index 0c51b7288978..f8953455db29 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
@@ -531,57 +531,6 @@ static void test_sockmap_skb_verdict_shutdown(void)
test_sockmap_pass_prog__destroy(skel);
}

-static void test_sockmap_stream_pass(void)
-{
- int zero = 0, sent, recvd;
- int verdict, parser;
- int err, map;
- int c = -1, p = -1;
- struct test_sockmap_pass_prog *pass = NULL;
- char snd[256] = "0123456789";
- char rcv[256] = "0";
-
- pass = test_sockmap_pass_prog__open_and_load();
- verdict = bpf_program__fd(pass->progs.prog_skb_verdict);
- parser = bpf_program__fd(pass->progs.prog_skb_parser);
- map = bpf_map__fd(pass->maps.sock_map_rx);
-
- err = bpf_prog_attach(parser, map, BPF_SK_SKB_STREAM_PARSER, 0);
- if (!ASSERT_OK(err, "bpf_prog_attach stream parser"))
- goto out;
-
- err = bpf_prog_attach(verdict, map, BPF_SK_SKB_STREAM_VERDICT, 0);
- if (!ASSERT_OK(err, "bpf_prog_attach stream verdict"))
- goto out;
-
- err = create_pair(AF_INET, SOCK_STREAM, &c, &p);
- if (err)
- goto out;
-
- /* sk_data_ready of 'p' will be replaced by strparser handler */
- err = bpf_map_update_elem(map, &zero, &p, BPF_NOEXIST);
- if (!ASSERT_OK(err, "bpf_map_update_elem(p)"))
- goto out_close;
-
- /*
- * as 'prog_skb_parser' return the original skb len and
- * 'prog_skb_verdict' return SK_PASS, the kernel will just
- * pass it through to original socket 'p'
- */
- sent = xsend(c, snd, sizeof(snd), 0);
- ASSERT_EQ(sent, sizeof(snd), "xsend(c)");
-
- recvd = recv_timeout(p, rcv, sizeof(rcv), SOCK_NONBLOCK,
- IO_TIMEOUT_SEC);
- ASSERT_EQ(recvd, sizeof(rcv), "recv_timeout(p)");
-
-out_close:
- close(c);
- close(p);
-
-out:
- test_sockmap_pass_prog__destroy(pass);
-}

static void test_sockmap_skb_verdict_fionread(bool pass_prog)
{
@@ -1101,8 +1050,6 @@ void test_sockmap_basic(void)
test_sockmap_progs_query(BPF_SK_SKB_VERDICT);
if (test__start_subtest("sockmap skb_verdict shutdown"))
test_sockmap_skb_verdict_shutdown();
- if (test__start_subtest("sockmap stream parser and verdict pass"))
- test_sockmap_stream_pass();
if (test__start_subtest("sockmap skb_verdict fionread"))
test_sockmap_skb_verdict_fionread(true);
if (test__start_subtest("sockmap skb_verdict fionread on drop"))
diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_strp.c b/tools/testing/selftests/bpf/prog_tests/sockmap_strp.c
new file mode 100644
index 000000000000..621b3b71888e
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_strp.c
@@ -0,0 +1,454 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <error.h>
+#include <netinet/tcp.h>
+#include <test_progs.h>
+#include "sockmap_helpers.h"
+#include "test_skmsg_load_helpers.skel.h"
+#include "test_sockmap_strp.skel.h"
+
+#define STRP_PKT_HEAD_LEN 4
+#define STRP_PKT_BODY_LEN 6
+#define STRP_PKT_FULL_LEN (STRP_PKT_HEAD_LEN + STRP_PKT_BODY_LEN)
+
+static const char packet[STRP_PKT_FULL_LEN] = "head+body\0";
+static const int test_packet_num = 100;
+
+/* Current implementation of tcp_bpf_recvmsg_parser() invokes data_ready
+ * with sk held if an skb exists in sk_receive_queue. Then for the
+ * data_ready implementation of strparser, it will delay the read
+ * operation if sk is held and EAGAIN is returned.
+ */
+static int sockmap_strp_consume_pre_data(int p)
+{
+ int recvd;
+ bool retried = false;
+ char rcv[10];
+
+retry:
+ errno = 0;
+ recvd = recv_timeout(p, rcv, sizeof(rcv), 0, 1);
+ if (recvd < 0 && errno == EAGAIN && retried == false) {
+ /* On the first call, EAGAIN will certainly be returned.
+ * A 1-second wait is enough for the workqueue to finish.
+ */
+ sleep(1);
+ retried = true;
+ goto retry;
+ }
+
+ if (!ASSERT_EQ(recvd, STRP_PKT_FULL_LEN, "recv error or truncated data") ||
+ !ASSERT_OK(memcmp(packet, rcv, STRP_PKT_FULL_LEN),
+ "data mismatch"))
+ return -1;
+ return 0;
+}
+
+static struct test_sockmap_strp *sockmap_strp_init(int *out_map, bool pass,
+ bool need_parser)
+{
+ struct test_sockmap_strp *strp = NULL;
+ int verdict, parser;
+ int err;
+
+ strp = test_sockmap_strp__open_and_load();
+ *out_map = bpf_map__fd(strp->maps.sock_map);
+
+ if (need_parser)
+ parser = bpf_program__fd(strp->progs.prog_skb_parser_partial);
+ else
+ parser = bpf_program__fd(strp->progs.prog_skb_parser);
+
+ if (pass)
+ verdict = bpf_program__fd(strp->progs.prog_skb_verdict_pass);
+ else
+ verdict = bpf_program__fd(strp->progs.prog_skb_verdict);
+
+ err = bpf_prog_attach(parser, *out_map, BPF_SK_SKB_STREAM_PARSER, 0);
+ if (!ASSERT_OK(err, "bpf_prog_attach stream parser"))
+ goto err;
+
+ err = bpf_prog_attach(verdict, *out_map, BPF_SK_SKB_STREAM_VERDICT, 0);
+ if (!ASSERT_OK(err, "bpf_prog_attach stream verdict"))
+ goto err;
+
+ return strp;
+err:
+ test_sockmap_strp__destroy(strp);
+ return NULL;
+}
+
+/* Dispatch packets to different socket by packet size:
+ *
+ * ------ ------
+ * | pkt4 || pkt1 |... > remote socket
+ * ------ ------ / ------ ------
+ * | pkt8 | pkt7 |...
+ * ------ ------ \ ------ ------
+ * | pkt3 || pkt2 |... > local socket
+ * ------ ------
+ */
+static void test_sockmap_strp_dispatch_pkt(int family, int sotype)
+{
+ int i, j, zero = 0, one = 1, recvd;
+ int err, map;
+ int c0 = -1, p0 = -1, c1 = -1, p1 = -1;
+ struct test_sockmap_strp *strp = NULL;
+ int test_cnt = 6;
+ char rcv[10];
+ struct {
+ char data[7];
+ int data_len;
+ int send_cnt;
+ int *receiver;
+ } send_dir[2] = {
+ /* data expected to deliver to local */
+ {"llllll", 6, 0, &p0},
+ /* data expected to deliver to remote */
+ {"rrrrr", 5, 0, &c1}
+ };
+
+ strp = sockmap_strp_init(&map, false, false);
+ if (!ASSERT_TRUE(strp, "sockmap_strp_init"))
+ return;
+
+ err = create_socket_pairs(family, sotype, &c0, &c1, &p0, &p1);
+ if (!ASSERT_OK(err, "create_socket_pairs()"))
+ goto out;
+
+ err = bpf_map_update_elem(map, &zero, &p0, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem(p0)"))
+ goto out_close;
+
+ err = bpf_map_update_elem(map, &one, &p1, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem(p1)"))
+ goto out_close;
+
+ err = setsockopt(c1, IPPROTO_TCP, TCP_NODELAY, &zero, sizeof(zero));
+ if (!ASSERT_OK(err, "setsockopt(TCP_NODELAY)"))
+ goto out_close;
+
+ /* deliver data with data size greater than 5 to local */
+ strp->data->verdict_max_size = 5;
+
+ for (i = 0; i < test_cnt; i++) {
+ int d = i % 2;
+
+ xsend(c0, send_dir[d].data, send_dir[d].data_len, 0);
+ send_dir[d].send_cnt++;
+ }
+
+ for (i = 0; i < 2; i++) {
+ for (j = 0; j < send_dir[i].send_cnt; j++) {
+ int expected = send_dir[i].data_len;
+
+ recvd = recv_timeout(*send_dir[i].receiver, rcv,
+ expected, MSG_DONTWAIT,
+ IO_TIMEOUT_SEC);
+ if (!ASSERT_EQ(recvd, expected, "recv_timeout()"))
+ goto out_close;
+ if (!ASSERT_OK(memcmp(send_dir[i].data, rcv, recvd),
+ "data mismatch"))
+ goto out_close;
+ }
+ }
+out_close:
+ close(c0);
+ close(c1);
+ close(p0);
+ close(p1);
+out:
+ test_sockmap_strp__destroy(strp);
+}
+
+/* We have multiple packets in one skb
+ * ------------ ------------ ------------
+ * | packet1 | packet2 | ...
+ * ------------ ------------ ------------
+ */
+static void test_sockmap_strp_multiple_pkt(int family, int sotype)
+{
+ int i, zero = 0;
+ int sent, recvd, total;
+ int err, map;
+ int c = -1, p = -1;
+ struct test_sockmap_strp *strp = NULL;
+ char *snd = NULL, *rcv = NULL;
+
+ strp = sockmap_strp_init(&map, true, true);
+ if (!ASSERT_TRUE(strp, "sockmap_strp_init"))
+ return;
+
+ err = create_pair(family, sotype, &c, &p);
+ if (err)
+ goto out;
+
+ err = bpf_map_update_elem(map, &zero, &p, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem(zero, p)"))
+ goto out_close;
+
+ /* construct multiple packets in one buffer */
+ total = test_packet_num * STRP_PKT_FULL_LEN;
+ snd = malloc(total);
+ rcv = malloc(total + 1);
+ if (!ASSERT_TRUE(snd, "malloc(snd)") ||
+ !ASSERT_TRUE(rcv, "malloc(rcv)"))
+ goto out_close;
+
+ for (i = 0; i < test_packet_num; i++) {
+ memcpy(snd + i * STRP_PKT_FULL_LEN,
+ packet, STRP_PKT_FULL_LEN);
+ }
+
+ sent = xsend(c, snd, total, 0);
+ if (!ASSERT_EQ(sent, total, "xsend(c)"))
+ goto out_close;
+
+ /* try to recv one more byte to avoid truncation check */
+ recvd = recv_timeout(p, rcv, total + 1, MSG_DONTWAIT, IO_TIMEOUT_SEC);
+ if (!ASSERT_EQ(recvd, total, "recv(rcv)"))
+ goto out_close;
+
+ /* we sent TCP segment with multiple encapsulation
+ * then check whether packets are handled correctly
+ */
+ if (!ASSERT_OK(memcmp(snd, rcv, total), "data mismatch"))
+ goto out_close;
+
+out_close:
+ close(c);
+ close(p);
+ if (snd)
+ free(snd);
+ if (rcv)
+ free(rcv);
+out:
+ test_sockmap_strp__destroy(strp);
+}
+
+/* Test strparser with partial read */
+static void test_sockmap_strp_partial_read(int family, int sotype)
+{
+ int zero = 0, recvd, off;
+ int err, map;
+ int c = -1, p = -1;
+ struct test_sockmap_strp *strp = NULL;
+ char rcv[STRP_PKT_FULL_LEN + 1] = "0";
+
+ strp = sockmap_strp_init(&map, true, true);
+ if (!ASSERT_TRUE(strp, "sockmap_strp_init"))
+ return;
+
+ err = create_pair(family, sotype, &c, &p);
+ if (err)
+ goto out;
+
+ /* sk_data_ready of 'p' will be replaced by strparser handler */
+ err = bpf_map_update_elem(map, &zero, &p, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem(zero, p)"))
+ goto out_close;
+
+ /* 1.1 send partial head, 1 byte header left */
+ off = STRP_PKT_HEAD_LEN - 1;
+ xsend(c, packet, off, 0);
+ recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT, 1);
+ if (!ASSERT_EQ(-1, recvd, "partial head sent, expected no data"))
+ goto out_close;
+
+ /* 1.2 send remaining head and body */
+ xsend(c, packet + off, STRP_PKT_FULL_LEN - off, 0);
+ recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT, IO_TIMEOUT_SEC);
+ if (!ASSERT_EQ(recvd, STRP_PKT_FULL_LEN, "expected full data"))
+ goto out_close;
+
+ /* 2.1 send partial head, 1 byte header left */
+ off = STRP_PKT_HEAD_LEN - 1;
+ xsend(c, packet, off, 0);
+
+ /* 2.2 send remaining head and partial body, 1 byte body left */
+ xsend(c, packet + off, STRP_PKT_FULL_LEN - off - 1, 0);
+ off = STRP_PKT_FULL_LEN - 1;
+ recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT, 1);
+ if (!ASSERT_EQ(-1, recvd, "partial body sent, expected no data"))
+ goto out_close;
+
+ /* 2.3 send remaining body */
+ xsend(c, packet + off, STRP_PKT_FULL_LEN - off, 0);
+ recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT, IO_TIMEOUT_SEC);
+ if (!ASSERT_EQ(recvd, STRP_PKT_FULL_LEN, "expected full data"))
+ goto out_close;
+
+out_close:
+ close(c);
+ close(p);
+
+out:
+ test_sockmap_strp__destroy(strp);
+}
+
+/* Test simple socket read/write with strparser + FIONREAD */
+static void test_sockmap_strp_pass(int family, int sotype, bool fionread)
+{
+ int zero = 0, pkt_size = STRP_PKT_FULL_LEN, sent, recvd, avail;
+ int err, map;
+ int c = -1, p = -1;
+ int test_cnt = 10, i;
+ struct test_sockmap_strp *strp = NULL;
+ char rcv[STRP_PKT_FULL_LEN + 1] = "0";
+
+ strp = sockmap_strp_init(&map, true, true);
+ if (!ASSERT_TRUE(strp, "sockmap_strp_init"))
+ return;
+
+ err = create_pair(family, sotype, &c, &p);
+ if (err)
+ goto out;
+
+ /* inject some data before bpf process, it should be read
+ * correctly because we check sk_receive_queue in
+ * tcp_bpf_recvmsg_parser().
+ */
+ sent = xsend(c, packet, pkt_size, 0);
+ if (!ASSERT_EQ(sent, pkt_size, "xsend(pre-data)"))
+ goto out_close;
+
+ /* sk_data_ready of 'p' will be replaced by strparser handler */
+ err = bpf_map_update_elem(map, &zero, &p, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem(p)"))
+ goto out_close;
+
+ /* consume previous data we injected */
+ if (sockmap_strp_consume_pre_data(p))
+ goto out_close;
+
+ /* Previously, we encountered issues such as deadlocks and
+ * sequence errors that resulted in the inability to read
+ * continuously. Therefore, we perform multiple iterations
+ * of testing here.
+ */
+ for (i = 0; i < test_cnt; i++) {
+ sent = xsend(c, packet, pkt_size, 0);
+ if (!ASSERT_EQ(sent, pkt_size, "xsend(c)"))
+ goto out_close;
+
+ recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT,
+ IO_TIMEOUT_SEC);
+ if (!ASSERT_EQ(recvd, pkt_size, "recv_timeout(p)") ||
+ !ASSERT_OK(memcmp(packet, rcv, pkt_size),
+ "memcmp, data mismatch"))
+ goto out_close;
+ }
+
+ if (fionread) {
+ sent = xsend(c, packet, pkt_size, 0);
+ if (!ASSERT_EQ(sent, pkt_size, "second xsend(c)"))
+ goto out_close;
+
+ err = ioctl(p, FIONREAD, &avail);
+ if (!ASSERT_OK(err, "ioctl(FIONREAD) error") ||
+ !ASSERT_EQ(avail, pkt_size, "ioctl(FIONREAD)"))
+ goto out_close;
+
+ recvd = recv_timeout(p, rcv, sizeof(rcv), MSG_DONTWAIT,
+ IO_TIMEOUT_SEC);
+ if (!ASSERT_EQ(recvd, pkt_size, "second recv_timeout(p)") ||
+ !ASSERT_OK(memcmp(packet, rcv, pkt_size),
+ "second memcmp, data mismatch"))
+ goto out_close;
+ }
+
+out_close:
+ close(c);
+ close(p);
+
+out:
+ test_sockmap_strp__destroy(strp);
+}
+
+/* Test strparser with verdict mode */
+static void test_sockmap_strp_verdict(int family, int sotype)
+{
+ int zero = 0, one = 1, sent, recvd, off;
+ int err, map;
+ int c0 = -1, p0 = -1, c1 = -1, p1 = -1;
+ struct test_sockmap_strp *strp = NULL;
+ char rcv[STRP_PKT_FULL_LEN + 1] = "0";
+
+ strp = sockmap_strp_init(&map, false, true);
+ if (!ASSERT_TRUE(strp, "sockmap_strp_init"))
+ return;
+
+ /* We simulate a reverse proxy server.
+ * When p0 receives data from c0, we forward it to c1.
+ * From c1's perspective, it will consider this data
+ * as being sent by p1.
+ */
+ err = create_socket_pairs(family, sotype, &c0, &c1, &p0, &p1);
+ if (!ASSERT_OK(err, "create_socket_pairs()"))
+ goto out;
+
+ err = bpf_map_update_elem(map, &zero, &p0, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem(p0)"))
+ goto out_close;
+
+ err = bpf_map_update_elem(map, &one, &p1, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem(p1)"))
+ goto out_close;
+
+ sent = xsend(c0, packet, STRP_PKT_FULL_LEN, 0);
+ if (!ASSERT_EQ(sent, STRP_PKT_FULL_LEN, "xsend(c0)"))
+ goto out_close;
+
+ recvd = recv_timeout(c1, rcv, sizeof(rcv), MSG_DONTWAIT,
+ IO_TIMEOUT_SEC);
+ if (!ASSERT_EQ(recvd, STRP_PKT_FULL_LEN, "recv_timeout(c1)") ||
+ !ASSERT_OK(memcmp(packet, rcv, STRP_PKT_FULL_LEN),
+ "received data does not match the sent data"))
+ goto out_close;
+
+ /* send again to ensure the stream is functioning correctly. */
+ sent = xsend(c0, packet, STRP_PKT_FULL_LEN, 0);
+ if (!ASSERT_EQ(sent, STRP_PKT_FULL_LEN, "second xsend(c0)"))
+ goto out_close;
+
+ /* partial read */
+ off = STRP_PKT_FULL_LEN / 2;
+ recvd = recv_timeout(c1, rcv, off, MSG_DONTWAIT,
+ IO_TIMEOUT_SEC);
+ recvd += recv_timeout(c1, rcv + off, sizeof(rcv) - off, MSG_DONTWAIT,
+ IO_TIMEOUT_SEC);
+
+ if (!ASSERT_EQ(recvd, STRP_PKT_FULL_LEN, "partial recv_timeout(c1)") ||
+ !ASSERT_OK(memcmp(packet, rcv, STRP_PKT_FULL_LEN),
+ "partial received data does not match the sent data"))
+ goto out_close;
+
+out_close:
+ close(c0);
+ close(c1);
+ close(p0);
+ close(p1);
+out:
+ test_sockmap_strp__destroy(strp);
+}
+
+void test_sockmap_strp(void)
+{
+ if (test__start_subtest("sockmap strp tcp pass"))
+ test_sockmap_strp_pass(AF_INET, SOCK_STREAM, false);
+ if (test__start_subtest("sockmap strp tcp v6 pass"))
+ test_sockmap_strp_pass(AF_INET6, SOCK_STREAM, false);
+ if (test__start_subtest("sockmap strp tcp pass fionread"))
+ test_sockmap_strp_pass(AF_INET, SOCK_STREAM, true);
+ if (test__start_subtest("sockmap strp tcp v6 pass fionread"))
+ test_sockmap_strp_pass(AF_INET6, SOCK_STREAM, true);
+ if (test__start_subtest("sockmap strp tcp verdict"))
+ test_sockmap_strp_verdict(AF_INET, SOCK_STREAM);
+ if (test__start_subtest("sockmap strp tcp v6 verdict"))
+ test_sockmap_strp_verdict(AF_INET6, SOCK_STREAM);
+ if (test__start_subtest("sockmap strp tcp partial read"))
+ test_sockmap_strp_partial_read(AF_INET, SOCK_STREAM);
+ if (test__start_subtest("sockmap strp tcp multiple packets"))
+ test_sockmap_strp_multiple_pkt(AF_INET, SOCK_STREAM);
+ if (test__start_subtest("sockmap strp tcp dispatch"))
+ test_sockmap_strp_dispatch_pkt(AF_INET, SOCK_STREAM);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_strp.c b/tools/testing/selftests/bpf/progs/test_sockmap_strp.c
new file mode 100644
index 000000000000..dde3d5bec515
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_sockmap_strp.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+int verdict_max_size = 10000;
+struct {
+ __uint(type, BPF_MAP_TYPE_SOCKMAP);
+ __uint(max_entries, 20);
+ __type(key, int);
+ __type(value, int);
+} sock_map SEC(".maps");
+
+SEC("sk_skb/stream_verdict")
+int prog_skb_verdict(struct __sk_buff *skb)
+{
+ __u32 one = 1;
+
+ if (skb->len > verdict_max_size)
+ return SK_PASS;
+
+ return bpf_sk_redirect_map(skb, &sock_map, one, 0);
+}
+
+SEC("sk_skb/stream_verdict")
+int prog_skb_verdict_pass(struct __sk_buff *skb)
+{
+ return SK_PASS;
+}
+
+SEC("sk_skb/stream_parser")
+int prog_skb_parser(struct __sk_buff *skb)
+{
+ return skb->len;
+}
+
+SEC("sk_skb/stream_parser")
+int prog_skb_parser_partial(struct __sk_buff *skb)
+{
+ /* agreement with the test program on a 4-byte size header
+ * and 6-byte body.
+ */
+ if (skb->len < 4) {
+ /* need more header to determine full length */
+ return 0;
+ }
+ /* return full length decoded from header.
+ * the return value may be larger than skb->len which
+ * means framework must wait body coming.
+ */
+ return 10;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.43.5