From: Jakub Sitnicki <jakub@cloudflare.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
John Fastabend <john.fastabend@gmail.com>,
Lorenz Bauer <lmb@cloudflare.com>, Martin Lau <kafai@fb.com>
Subject: [PATCH bpf-next v7 08/11] bpf: Allow selecting reuseport socket from a SOCKMAP/SOCKHASH
Date: Tue, 18 Feb 2020 17:10:20 +0000 [thread overview]
Message-ID: <20200218171023.844439-9-jakub@cloudflare.com> (raw)
In-Reply-To: <20200218171023.844439-1-jakub@cloudflare.com>
SOCKMAP & SOCKHASH now support storing references to listening
sockets. Nothing keeps us from using these map types a collection of
sockets to select from in BPF reuseport programs. Whitelist the map types
with the bpf_sk_select_reuseport helper.
The restriction that the socket has to be a member of a reuseport group
still applies. Sockets in SOCKMAP/SOCKHASH that don't have sk_reuseport_cb
set are not a valid target and we signal it with -EINVAL.
The main benefit from this change is that, in contrast to
REUSEPORT_SOCKARRAY, SOCK{MAP,HASH} don't impose a restriction that a
listening socket can be just one BPF map at the same time.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
kernel/bpf/verifier.c | 10 +++++++---
net/core/filter.c | 15 ++++++++++-----
2 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1cc945daa9c8..6d15dfbd4b88 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3693,14 +3693,16 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
if (func_id != BPF_FUNC_sk_redirect_map &&
func_id != BPF_FUNC_sock_map_update &&
func_id != BPF_FUNC_map_delete_elem &&
- func_id != BPF_FUNC_msg_redirect_map)
+ func_id != BPF_FUNC_msg_redirect_map &&
+ func_id != BPF_FUNC_sk_select_reuseport)
goto error;
break;
case BPF_MAP_TYPE_SOCKHASH:
if (func_id != BPF_FUNC_sk_redirect_hash &&
func_id != BPF_FUNC_sock_hash_update &&
func_id != BPF_FUNC_map_delete_elem &&
- func_id != BPF_FUNC_msg_redirect_hash)
+ func_id != BPF_FUNC_msg_redirect_hash &&
+ func_id != BPF_FUNC_sk_select_reuseport)
goto error;
break;
case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
@@ -3774,7 +3776,9 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
goto error;
break;
case BPF_FUNC_sk_select_reuseport:
- if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY)
+ if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
+ map->map_type != BPF_MAP_TYPE_SOCKMAP &&
+ map->map_type != BPF_MAP_TYPE_SOCKHASH)
goto error;
break;
case BPF_FUNC_map_peek_elem:
diff --git a/net/core/filter.c b/net/core/filter.c
index c180871e606d..77d2f471b3bb 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8620,6 +8620,7 @@ struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
BPF_CALL_4(sk_select_reuseport, struct sk_reuseport_kern *, reuse_kern,
struct bpf_map *, map, void *, key, u32, flags)
{
+ bool is_sockarray = map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY;
struct sock_reuseport *reuse;
struct sock *selected_sk;
@@ -8628,12 +8629,16 @@ BPF_CALL_4(sk_select_reuseport, struct sk_reuseport_kern *, reuse_kern,
return -ENOENT;
reuse = rcu_dereference(selected_sk->sk_reuseport_cb);
- if (!reuse)
- /* selected_sk is unhashed (e.g. by close()) after the
- * above map_lookup_elem(). Treat selected_sk has already
- * been removed from the map.
+ if (!reuse) {
+ /* reuseport_array has only sk with non NULL sk_reuseport_cb.
+ * The only (!reuse) case here is - the sk has already been
+ * unhashed (e.g. by close()), so treat it as -ENOENT.
+ *
+ * Other maps (e.g. sock_map) do not provide this guarantee and
+ * the sk may never be in the reuseport group to begin with.
*/
- return -ENOENT;
+ return is_sockarray ? -ENOENT : -EINVAL;
+ }
if (unlikely(reuse->reuseport_id != reuse_kern->reuseport_id)) {
struct sock *sk;
--
2.24.1
next prev parent reply other threads:[~2020-02-18 17:10 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 17:10 [PATCH bpf-next v7 00/11] Extend SOCKMAP/SOCKHASH to store listening sockets Jakub Sitnicki
2020-02-18 17:10 ` [PATCH bpf-next v7 01/11] net, sk_msg: Annotate lockless access to sk_prot on clone Jakub Sitnicki
2020-02-18 17:10 ` [PATCH bpf-next v7 02/11] net, sk_msg: Clear sk_user_data pointer on clone if tagged Jakub Sitnicki
2020-02-18 17:10 ` [PATCH bpf-next v7 03/11] tcp_bpf: Don't let child socket inherit parent protocol ops on copy Jakub Sitnicki
2020-02-21 3:28 ` John Fastabend
2020-02-18 17:10 ` [PATCH bpf-next v7 04/11] bpf, sockmap: Allow inserting listening TCP sockets into sockmap Jakub Sitnicki
2020-02-21 3:33 ` John Fastabend
2020-02-18 17:10 ` [PATCH bpf-next v7 05/11] bpf, sockmap: Don't set up upcalls and progs for listening sockets Jakub Sitnicki
2020-02-21 3:42 ` John Fastabend
2020-02-18 17:10 ` [PATCH bpf-next v7 06/11] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2020-02-21 3:45 ` John Fastabend
2020-02-18 17:10 ` [PATCH bpf-next v7 07/11] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP/SOCKHASH Jakub Sitnicki
2020-02-21 3:46 ` John Fastabend
2020-02-18 17:10 ` Jakub Sitnicki [this message]
2020-02-18 17:10 ` [PATCH bpf-next v7 09/11] net: Generate reuseport group ID on group creation Jakub Sitnicki
2020-02-18 17:10 ` [PATCH bpf-next v7 10/11] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP/SOCKHASH Jakub Sitnicki
2020-02-21 3:52 ` John Fastabend
2020-02-18 17:10 ` [PATCH bpf-next v7 11/11] selftests/bpf: Tests for sockmap/sockhash holding listening sockets Jakub Sitnicki
2020-02-21 3:56 ` John Fastabend
2020-02-21 21:41 ` [PATCH bpf-next v7 00/11] Extend SOCKMAP/SOCKHASH to store " Daniel Borkmann
2020-02-22 0:47 ` Alexei Starovoitov
2020-02-22 13:49 ` Jakub Sitnicki
2020-02-23 21:43 ` Alexei Starovoitov
2020-02-24 13:59 ` Jakub Sitnicki
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