[PATCH bpf v5 0/3] bpf: fix wrong copied_seq calculation and add tests

[PATCH bpf v5 0/3] bpf: fix wrong copied_seq calculation and add tests

[Jiayuan Chen]

A previous commit described in this topic
http://lore.kernel.org/bpf/20230523025618.113937-9-john.fastabend@gmail.com
directly updated 'sk->copied_seq' in the tcp_eat_skb() function when the
action of a BPF program was SK_REDIRECT. For other actions, like SK_PASS,
the update logic for 'sk->copied_seq' was moved to
tcp_bpf_recvmsg_parser() to ensure the accuracy of the 'fionread' feature.

That commit works for a single stream_verdict scenario, as it also
modified 'sk_data_ready->sk_psock_verdict_data_ready->tcp_read_skb'
to remove updating 'sk->copied_seq'.

However, for programs where both stream_parser and stream_verdict are
active(strparser purpose), tcp_read_sock() was used instead of
tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock)
tcp_read_sock() now still update 'sk->copied_seq', leading to duplicated
updates.

In summary, for strparser + SK_PASS, copied_seq is redundantly calculated
in both tcp_read_sock() and tcp_bpf_recvmsg_parser().

The issue causes incorrect copied_seq calculations, which prevent
correct data reads from the recv() interface in user-land.

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

Fixes: e5c6de5fa025 ("bpf, sockmap: Incorrectly handling copied_seq")

---
V3 -> v5:
https://lore.kernel.org/bpf/20241218053408.437295-1-mrpre@163.com/
Avoid introducing new proto_ops. (Daniel Borkmann).
Add more edge test cases for strparser + bpf.
Fix patchwork fail of test cases code.
Fix psock fetch without rcu lock.

V1 -> V3:
https://lore.kernel.org/bpf/20241209152740.281125-1-mrpre@163.com/
Fix patchwork fail by adding Fixes tag.
Save skb data offset for ENOMEM. (John Fastabend)
---

Jiayuan Chen (3):
  bpf: fix wrong copied_seq calculation
  selftests/bpf: add strparser test for bpf
  bpf, strparser, docs: Add new callback for bpf

 Documentation/networking/strparser.rst        |  11 +-
 include/linux/skmsg.h                         |   2 +
 include/net/strparser.h                       |   2 +
 include/net/tcp.h                             |   3 +
 net/core/skmsg.c                              |  51 ++
 net/ipv4/tcp.c                                |  31 +-
 net/strparser/strparser.c                     |  11 +-
 .../selftests/bpf/prog_tests/sockmap_basic.c  |  53 --
 .../selftests/bpf/prog_tests/sockmap_strp.c   | 452 ++++++++++++++++++
 .../selftests/bpf/progs/test_sockmap_strp.c   |  53 ++
 10 files changed, 608 insertions(+), 61 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

-- 
2.43.5

[PATCH bpf v5 1/3] bpf: fix wrong copied_seq calculation

[Jiayuan Chen]

'sk->copied_seq' was updated in the tcp_eat_skb() function when the
action of a BPF program was SK_REDIRECT. For other actions, like SK_PASS,
the update logic for 'sk->copied_seq' was moved to
tcp_bpf_recvmsg_parser() to ensure the accuracy of the 'fionread' feature.

It works for a single stream_verdict scenario, as it also modified
'sk_data_ready->sk_psock_verdict_data_ready->tcp_read_skb'
to remove updating 'sk->copied_seq'.

However, for programs where both stream_parser and stream_verdict are
active(strparser purpose), tcp_read_sock() was used instead of
tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock)
tcp_read_sock() now still update 'sk->copied_seq', leading to duplicated
updates.

In summary, for strparser + SK_PASS, copied_seq is redundantly calculated
in both tcp_read_sock() and tcp_bpf_recvmsg_parser().

The issue causes incorrect copied_seq calculations, which prevent
correct data reads from the recv() interface in user-land.

We do not want to add new proto_ops to implement a new version of
tcp_read_sock, as this would introduce code complexity [1].

[1]: https://lore.kernel.org/bpf/20241218053408.437295-1-mrpre@163.com
Fixes: e5c6de5fa025 ("bpf, sockmap: Incorrectly handling copied_seq")
Co-developed-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Jiayuan Chen <mrpre@163.com>
---
 include/linux/skmsg.h     |  2 ++
 include/net/strparser.h   |  2 ++
 include/net/tcp.h         |  3 +++
 net/core/skmsg.c          | 51 +++++++++++++++++++++++++++++++++++++++
 net/ipv4/tcp.c            | 31 ++++++++++++++++++++----
 net/strparser/strparser.c | 11 +++++++--
 6 files changed, 93 insertions(+), 7 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 2cbe0c22a32f..ed1fdb0aa044 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -85,6 +85,8 @@ struct sk_psock {
 	struct sock			*sk_redir;
 	u32				apply_bytes;
 	u32				cork_bytes;
+	u32				copied_seq;
+	u32				ingress_bytes;
 	u32				eval;
 	bool				redir_ingress; /* undefined if sk_redir is null */
 	struct sk_msg			*cork;
diff --git a/include/net/strparser.h b/include/net/strparser.h
index 41e2ce9e9e10..0a83010b3a64 100644
--- a/include/net/strparser.h
+++ b/include/net/strparser.h
@@ -43,6 +43,8 @@ struct strparser;
 struct strp_callbacks {
 	int (*parse_msg)(struct strparser *strp, struct sk_buff *skb);
 	void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb);
+	int (*read_sock)(struct strparser *strp, read_descriptor_t *desc,
+			 sk_read_actor_t recv_actor);
 	int (*read_sock_done)(struct strparser *strp, int err);
 	void (*abort_parser)(struct strparser *strp, int err);
 	void (*lock)(struct strparser *strp);
diff --git a/include/net/tcp.h b/include/net/tcp.h
index e9b37b76e894..36db593984eb 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -729,6 +729,9 @@ void tcp_get_info(struct sock *, struct tcp_info *);
 /* Read 'sendfile()'-style from a TCP socket */
 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
 		  sk_read_actor_t recv_actor);
+int tcp_read_sock_noack(struct sock *sk, read_descriptor_t *desc,
+			sk_read_actor_t recv_actor, u32 noack,
+			u32 *copied_seq);
 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
 struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off);
 void tcp_read_done(struct sock *sk, size_t len);
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 61f3f3d4e528..fb20193dd50a 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -549,6 +549,7 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
 			return num_sge;
 	}
 
+	psock->ingress_bytes += len;
 	copied = len;
 	msg->sg.start = 0;
 	msg->sg.size = copied;
@@ -1092,6 +1093,52 @@ static int sk_psock_strp_read_done(struct strparser *strp, int err)
 	return err;
 }
 
+static int sk_psock_strp_read_sock(struct strparser *strp,
+				   read_descriptor_t *desc,
+				   sk_read_actor_t recv_actor)
+{
+	struct sock *sk = strp->sk;
+	struct sk_psock *psock;
+	struct tcp_sock *tp;
+	int copied = 0;
+
+	if (WARN_ON(!sk_is_tcp(sk))) {
+		desc->error = -EINVAL;
+		return 0;
+	}
+
+	tp = tcp_sk(sk);
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (WARN_ON(!psock)) {
+		desc->error = -EINVAL;
+		goto out;
+	}
+
+	psock->ingress_bytes = 0;
+	/* We could easily add copied_seq and noack into desc then call
+	 * ops->read_sock without calling symbol directly. But unfortunately
+	 * most descriptors used by other modules are not inited with zero.
+	 * Also replacing ops->read_sock can't be workd without introducing
+	 * new ops as ops itself is located in rodata segment.
+	 */
+	copied = tcp_read_sock_noack(sk, desc, recv_actor, 1,
+				     &psock->copied_seq);
+	if (copied < 0)
+		goto out;
+	/* recv_actor may redirect skb to another socket(SK_REDIRECT) or
+	 * just put skb into ingress queue of current socket(SK_PASS).
+	 * For SK_REDIRECT, we need 'ack' the frame immediately but for
+	 * SK_PASS, the 'ack' was delay to tcp_bpf_recvmsg_parser()
+	 */
+	tp->copied_seq = psock->copied_seq - psock->ingress_bytes;
+	tcp_rcv_space_adjust(sk);
+	__tcp_cleanup_rbuf(sk, copied - psock->ingress_bytes);
+out:
+	rcu_read_unlock();
+	return copied;
+}
+
 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
 {
 	struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
@@ -1136,6 +1183,7 @@ int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 
 	static const struct strp_callbacks cb = {
 		.rcv_msg	= sk_psock_strp_read,
+		.read_sock	= sk_psock_strp_read_sock,
 		.read_sock_done	= sk_psock_strp_read_done,
 		.parse_msg	= sk_psock_strp_parse,
 	};
@@ -1144,6 +1192,9 @@ int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 	if (!ret)
 		sk_psock_set_state(psock, SK_PSOCK_RX_STRP_ENABLED);
 
+	if (sk_is_tcp(sk))
+		psock->copied_seq = tcp_sk(sk)->copied_seq;
+
 	return ret;
 }
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0d704bda6c41..32de16077ca7 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1565,12 +1565,13 @@ EXPORT_SYMBOL(tcp_recv_skb);
  *	  or for 'peeking' the socket using this routine
  *	  (although both would be easy to implement).
  */
-int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
-		  sk_read_actor_t recv_actor)
+static int __tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
+			   sk_read_actor_t recv_actor, u32 noack,
+			   u32 *copied_seq)
 {
 	struct sk_buff *skb;
 	struct tcp_sock *tp = tcp_sk(sk);
-	u32 seq = tp->copied_seq;
+	u32 seq = *copied_seq;
 	u32 offset;
 	int copied = 0;
 
@@ -1624,9 +1625,12 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
 		tcp_eat_recv_skb(sk, skb);
 		if (!desc->count)
 			break;
-		WRITE_ONCE(tp->copied_seq, seq);
+		WRITE_ONCE(*copied_seq, seq);
 	}
-	WRITE_ONCE(tp->copied_seq, seq);
+	WRITE_ONCE(*copied_seq, seq);
+
+	if (noack)
+		goto out;
 
 	tcp_rcv_space_adjust(sk);
 
@@ -1635,10 +1639,27 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
 		tcp_recv_skb(sk, seq, &offset);
 		tcp_cleanup_rbuf(sk, copied);
 	}
+out:
 	return copied;
 }
+
+int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
+		  sk_read_actor_t recv_actor)
+{
+	return __tcp_read_sock(sk, desc, recv_actor,
+			       0, &tcp_sk(sk)->copied_seq);
+}
 EXPORT_SYMBOL(tcp_read_sock);
 
+int tcp_read_sock_noack(struct sock *sk, read_descriptor_t *desc,
+			sk_read_actor_t recv_actor, u32 noack,
+			u32 *copied_seq)
+{
+	return __tcp_read_sock(sk, desc, recv_actor,
+			       noack, copied_seq);
+}
+EXPORT_SYMBOL(tcp_read_sock_noack);
+
 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
 {
 	struct sk_buff *skb;
diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c
index 8299ceb3e373..95696f42647e 100644
--- a/net/strparser/strparser.c
+++ b/net/strparser/strparser.c
@@ -347,7 +347,10 @@ static int strp_read_sock(struct strparser *strp)
 	struct socket *sock = strp->sk->sk_socket;
 	read_descriptor_t desc;
 
-	if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
+	if (unlikely(!sock || !sock->ops))
+		return -EBUSY;
+
+	if (unlikely(!strp->cb.read_sock && !sock->ops->read_sock))
 		return -EBUSY;
 
 	desc.arg.data = strp;
@@ -355,7 +358,10 @@ static int strp_read_sock(struct strparser *strp)
 	desc.count = 1; /* give more than one skb per call */
 
 	/* sk should be locked here, so okay to do read_sock */
-	sock->ops->read_sock(strp->sk, &desc, strp_recv);
+	if (strp->cb.read_sock)
+		strp->cb.read_sock(strp, &desc, strp_recv);
+	else
+		sock->ops->read_sock(strp->sk, &desc, strp_recv);
 
 	desc.error = strp->cb.read_sock_done(strp, desc.error);
 
@@ -468,6 +474,7 @@ int strp_init(struct strparser *strp, struct sock *sk,
 	strp->cb.unlock = cb->unlock ? : strp_sock_unlock;
 	strp->cb.rcv_msg = cb->rcv_msg;
 	strp->cb.parse_msg = cb->parse_msg;
+	strp->cb.read_sock = cb->read_sock;
 	strp->cb.read_sock_done = cb->read_sock_done ? : default_read_sock_done;
 	strp->cb.abort_parser = cb->abort_parser ? : strp_abort_strp;
 
-- 
2.43.5

[PATCH bpf v5 2/3] selftests/bpf: add strparser test for bpf

[Jiayuan Chen]

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

Signed-off-by: Jiayuan Chen <mrpre@163.com>
---
 .../selftests/bpf/prog_tests/sockmap_basic.c  |  53 --
 .../selftests/bpf/prog_tests/sockmap_strp.c   | 452 ++++++++++++++++++
 .../selftests/bpf/progs/test_sockmap_strp.c   |  53 ++
 3 files changed, 505 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 884ad87783d5..244057f49970 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..d3178a7a0e29
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_strp.c
@@ -0,0 +1,452 @@
+// 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() invoke
+ * data_ready with sk held if skb exist in sk_receive_queue.
+ * Then for data_ready implementation of strparser, it will
+ * delay the read operation if sk was 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.
+		 * Waiting 1 second is pretty enough wait workqueue finish.
+		 */
+		sleep(1);
+		retried = true;
+		goto retry;
+	}
+
+	if (!ASSERT_EQ(recvd, STRP_PKT_FULL_LEN, "recv_timeout(pre-data)") ||
+	    !ASSERT_OK(memcmp(packet, rcv, STRP_PKT_FULL_LEN),
+				"memcmp pre-data"))
+		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 |...
+ *  ------ ------     \ ------  ------
+ *                     | pkt2 || pkt3 |... > 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),
+				       "memcmp(rcv)"))
+				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), "memcmp(snd, rcv)"))
+		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, "insufficient head, should no data recvd"))
+		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, "should full data recvd"))
+		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, "insufficient body, should no data read"))
+		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, "should full data recvd"))
+		goto out_close;
+
+out_close:
+	close(c);
+	close(p);
+
+out:
+	test_sockmap_strp__destroy(strp);
+}
+
+/* Test simple soket 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"))
+			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"))
+			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(c1)"))
+		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(p1)") ||
+	    !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

[PATCH bpf v5 3/3] bpf, strparser, docs: Add new callback for bpf

[Jiayuan Chen]

sockmap with strparser need customized read operations to fix copied_seq
error.

Signed-off-by: Jiayuan Chen <mrpre@163.com>
---
 Documentation/networking/strparser.rst | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/strparser.rst b/Documentation/networking/strparser.rst
index 6cab1f74ae05..e41c18eee2f4 100644
--- a/Documentation/networking/strparser.rst
+++ b/Documentation/networking/strparser.rst
@@ -112,7 +112,7 @@ Functions
 Callbacks
 =========
 
-There are six callbacks:
+There are seven callbacks:
 
     ::
 
@@ -182,6 +182,15 @@ There are six callbacks:
     the length of the message. skb->len - offset may be greater
     then full_len since strparser does not trim the skb.
 
+    ::
+
+	int (*read_sock)(struct strparser *strp, read_descriptor_t *desc,
+                     sk_read_actor_t recv_actor);
+
+    read_sock is called when the user specify it, allowing for customized
+    read operations. If the callback is not set (NULL in strp_init) native
+    read_sock operation of the socket is used.
+
     ::
 
 	int (*read_sock_done)(struct strparser *strp, int err);
-- 
2.43.5

Re: [PATCH bpf v5 1/3] bpf: fix wrong copied_seq calculation

[Jakub Kicinski]

On Thu,  9 Jan 2025 17:43:59 +0800 Jiayuan Chen wrote:
> However, for programs where both stream_parser and stream_verdict are
> active(strparser purpose), tcp_read_sock() was used instead of
> tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock)
> tcp_read_sock() now still update 'sk->copied_seq', leading to duplicated
> updates.

To state the obvious feels like the abstraction between TCP and psock
has broken down pretty severely at this stage. You're modifying TCP
and straight up calling TCP functions from skmsg.c :(

> +int tcp_read_sock_noack(struct sock *sk, read_descriptor_t *desc,
> +			sk_read_actor_t recv_actor, u32 noack,
> +			u32 *copied_seq)
> +{
> +	return __tcp_read_sock(sk, desc, recv_actor,
> +			       noack, copied_seq);
> +}
> +EXPORT_SYMBOL(tcp_read_sock_noack);

Pretty sure you don't have to export this. skmsg can't be a module.

Re: [PATCH bpf v5 1/3] bpf: fix wrong copied_seq calculation

[Jiayuan Chen]

On Mon, Jan 13, 2025 at 04:04:04PM +0800, Jakub Kicinski wrote:
> On Thu,  9 Jan 2025 17:43:59 +0800 Jiayuan Chen wrote:
> > However, for programs where both stream_parser and stream_verdict are
> > active(strparser purpose), tcp_read_sock() was used instead of
> > tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock)
> > tcp_read_sock() now still update 'sk->copied_seq', leading to duplicated
> > updates.
> 
> To state the obvious feels like the abstraction between TCP and psock
> has broken down pretty severely at this stage. You're modifying TCP
> and straight up calling TCP functions from skmsg.c :(
>
You are right!

How about we construct code like this:

sk_psock_strp_read_sock(strp)    skmsg.c
    tcp_bpf_strp_read_sock(sk)   tcp_bpf.c
        tcp_read_sock_noack(sk)  tcp.c

In skmsg.c we just register read_sock handler for strparser, then move
core code into tcp_bpf.c. I believe it makes more sense than before as
there already exist some psock with tcp operation(especially ops handler)
implemented in tcp_bpf.c.
 
> > +int tcp_read_sock_noack(struct sock *sk, read_descriptor_t *desc,
> > +			sk_read_actor_t recv_actor, u32 noack,
> > +			u32 *copied_seq)
> > +{
> > +	return __tcp_read_sock(sk, desc, recv_actor,
> > +			       noack, copied_seq);
> > +}
> > +EXPORT_SYMBOL(tcp_read_sock_noack);
> 
> Pretty sure you don't have to export this. skmsg can't be a module.
ok, i will remove it.

Re: [PATCH bpf v5 1/3] bpf: fix wrong copied_seq calculation

[Jakub Sitnicki]

On Thu, Jan 09, 2025 at 05:43 PM +08, Jiayuan Chen wrote:
> 'sk->copied_seq' was updated in the tcp_eat_skb() function when the
> action of a BPF program was SK_REDIRECT. For other actions, like SK_PASS,
> the update logic for 'sk->copied_seq' was moved to
> tcp_bpf_recvmsg_parser() to ensure the accuracy of the 'fionread' feature.
>
> It works for a single stream_verdict scenario, as it also modified
> 'sk_data_ready->sk_psock_verdict_data_ready->tcp_read_skb'
> to remove updating 'sk->copied_seq'.
>
> However, for programs where both stream_parser and stream_verdict are
> active(strparser purpose), tcp_read_sock() was used instead of
> tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock)
> tcp_read_sock() now still update 'sk->copied_seq', leading to duplicated
> updates.
>
> In summary, for strparser + SK_PASS, copied_seq is redundantly calculated
> in both tcp_read_sock() and tcp_bpf_recvmsg_parser().
>
> The issue causes incorrect copied_seq calculations, which prevent
> correct data reads from the recv() interface in user-land.
>
> We do not want to add new proto_ops to implement a new version of
> tcp_read_sock, as this would introduce code complexity [1].
>
> [1]: https://lore.kernel.org/bpf/20241218053408.437295-1-mrpre@163.com
> Fixes: e5c6de5fa025 ("bpf, sockmap: Incorrectly handling copied_seq")
> Co-developed-by: Jakub Sitnicki <jakub@cloudflare.com>
> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
> Signed-off-by: Jiayuan Chen <mrpre@163.com>
> ---

No need to put me down as an author.
If you want you can me with a Suggested-by.

Also, please remove my Signed-off-by.
I will review these patches, but I haven't authored them.

Re: [PATCH bpf v5 1/3] bpf: fix wrong copied_seq calculation

[Jakub Kicinski]

On Tue, 14 Jan 2025 14:35:34 +0800 Jiayuan Chen wrote:
> > To state the obvious feels like the abstraction between TCP and psock
> > has broken down pretty severely at this stage. You're modifying TCP
> > and straight up calling TCP functions from skmsg.c :(
> >  
> You are right!
> 
> How about we construct code like this:
> 
> sk_psock_strp_read_sock(strp)    skmsg.c
>     tcp_bpf_strp_read_sock(sk)   tcp_bpf.c
>         tcp_read_sock_noack(sk)  tcp.c
> 
> In skmsg.c we just register read_sock handler for strparser, then move
> core code into tcp_bpf.c. I believe it makes more sense than before as
> there already exist some psock with tcp operation(especially ops handler)
> implemented in tcp_bpf.c.

Yes, that's slightly better, thanks