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From: Jakub Sitnicki <jakub@cloudflare.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
	Martin KaFai Lau <kafai@fb.com>
Subject: [PATCH bpf-next v5 06/12] bpf, sockmap: Don't set up sockmap progs for listening sockets
Date: Mon, 27 Jan 2020 13:55:28 +0100	[thread overview]
Message-ID: <20200127125534.137492-7-jakub@cloudflare.com> (raw)
In-Reply-To: <20200127125534.137492-1-jakub@cloudflare.com>

Now that sockmap can hold listening sockets, when setting up the psock we
will (i) grab references to verdict/parser progs, and (2) override socket
upcalls sk_data_ready and sk_write_space.

We cannot redirect to listening sockets so we don't need to link the socket
to the BPF progs, but more importantly we don't want the listening socket
to have overridden upcalls because they would get inherited by child
sockets cloned from it.

Introduce a separate initialization path for listening sockets that does
not change the upcalls and ignores the BPF progs.

Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
 net/core/sock_map.c | 45 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 954c4d23bc01..cadae12bb3d4 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -228,6 +228,30 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
 	return ret;
 }
 
+static int sock_map_link_no_progs(struct bpf_map *map, struct sock *sk)
+{
+	struct sk_psock *psock;
+	int ret;
+
+	psock = sk_psock_get_checked(sk);
+	if (IS_ERR(psock))
+		return PTR_ERR(psock);
+
+	if (psock) {
+		tcp_bpf_reinit(sk);
+		return 0;
+	}
+
+	psock = sk_psock_init(sk, map->numa_node);
+	if (!psock)
+		return -ENOMEM;
+
+	ret = tcp_bpf_init(sk);
+	if (ret < 0)
+		sk_psock_put(sk, psock);
+	return ret;
+}
+
 static void sock_map_free(struct bpf_map *map)
 {
 	struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
@@ -333,6 +357,12 @@ static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next)
 	return 0;
 }
 
+/* Is sock in a state that allows redirecting from/into it? */
+static bool sock_map_redirect_okay(const struct sock *sk)
+{
+	return sk->sk_state != TCP_LISTEN;
+}
+
 static int sock_map_update_common(struct bpf_map *map, u32 idx,
 				  struct sock *sk, u64 flags)
 {
@@ -355,7 +385,14 @@ static int sock_map_update_common(struct bpf_map *map, u32 idx,
 	if (!link)
 		return -ENOMEM;
 
-	ret = sock_map_link(map, &stab->progs, sk);
+	/* Only sockets we can redirect into/from in BPF need to hold
+	 * refs to parser/verdict progs and have their sk_data_ready
+	 * and sk_write_space callbacks overridden.
+	 */
+	if (sock_map_redirect_okay(sk))
+		ret = sock_map_link(map, &stab->progs, sk);
+	else
+		ret = sock_map_link_no_progs(map, sk);
 	if (ret < 0)
 		goto out_free;
 
@@ -422,12 +459,6 @@ static bool sock_hash_sk_is_suitable(const struct sock *sk)
 				      TCPF_SYN_RECV);
 }
 
-/* Is sock in a state that allows redirecting into it? */
-static bool sock_map_redirect_okay(const struct sock *sk)
-{
-	return sk->sk_state != TCP_LISTEN;
-}
-
 static int sock_map_update_elem(struct bpf_map *map, void *key,
 				void *value, u64 flags)
 {
-- 
2.24.1


  parent reply	other threads:[~2020-01-27 12:56 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-27 12:55 [PATCH bpf-next v5 00/12] Extend SOCKMAP to store " Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 01/12] bpf, sk_msg: Don't clear saved sock proto on restore Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 02/12] net, sk_msg: Annotate lockless access to sk_prot on clone Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 03/12] net, sk_msg: Clear sk_user_data pointer on clone if tagged Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 04/12] tcp_bpf: Don't let child socket inherit parent protocol ops on copy Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 05/12] bpf, sockmap: Allow inserting listening TCP sockets into sockmap Jakub Sitnicki
2020-01-27 12:55 ` Jakub Sitnicki [this message]
2020-01-27 12:55 ` [PATCH bpf-next v5 07/12] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 08/12] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 09/12] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 10/12] net: Generate reuseport group ID on group creation Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 11/12] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2020-01-27 12:55 ` [PATCH bpf-next v5 12/12] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
2020-03-11 18:48   ` Andrii Nakryiko
2020-03-11 19:49     ` Jakub Sitnicki
2020-03-11 21:02       ` Andrii Nakryiko
2020-03-12 17:25         ` Jakub Sitnicki
2020-01-27 13:01 ` [PATCH bpf-next v5 00/12] Extend SOCKMAP to store " Jakub Sitnicki
2020-01-27 13:05 ` Jakub Sitnicki

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