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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jakub Sitnicki <jakub@cloudflare.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
	kernel-team@cloudflare.com,
	John Fastabend <john.fastabend@gmail.com>,
	Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH bpf-next 5/8] bpf: Allow selecting reuseport socket from a SOCKMAP
Date: Sun, 24 Nov 2019 17:24:41 -0800	[thread overview]
Message-ID: <20191125012440.crbufwpokttx67du@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20191123110751.6729-6-jakub@cloudflare.com>

On Sat, Nov 23, 2019 at 12:07:48PM +0100, Jakub Sitnicki wrote:
> SOCKMAP now supports storing references to listening sockets. Nothing keeps
> us from using it as an array of sockets to select from in SK_REUSEPORT
> programs.
> 
> Whitelist the map type with the BPF helper for selecting socket. However,
> impose a restriction that the selected socket needs to be a listening TCP
> socket or a bound UDP socket (connected or not).
> 
> The only other map type that works with the BPF reuseport helper,
> REUSEPORT_SOCKARRAY, has a corresponding check in its update operation
> handler.
> 
> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
> ---
>  kernel/bpf/verifier.c | 6 ++++--
>  net/core/filter.c     | 2 ++
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index a0482e1c4a77..111a1eb543ab 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -3685,7 +3685,8 @@ 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:
> @@ -3766,7 +3767,8 @@ 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)
>  			goto error;
>  		break;
>  	case BPF_FUNC_map_peek_elem:
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 49ded4a7588a..e3fb77353248 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -8723,6 +8723,8 @@ BPF_CALL_4(sk_select_reuseport, struct sk_reuseport_kern *, reuse_kern,
>  	selected_sk = map->ops->map_lookup_elem(map, key);
>  	if (!selected_sk)
>  		return -ENOENT;
> +	if (!sock_flag(selected_sk, SOCK_RCU_FREE))
> +		return -EINVAL;

hmm. I wonder whether this breaks existing users...
Martin,
what do you think?
Could you also take a look at other patches too?
In particular patch 7?


  parent reply	other threads:[~2019-11-25  1:24 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-23 11:07 [PATCH bpf-next 0/8] Extend SOCKMAP to store listening sockets Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 1/8] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2019-11-24  5:32   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 2/8] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2019-11-24  5:35   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 3/8] bpf, sockmap: Allow inserting listening TCP sockets into SOCKMAP Jakub Sitnicki
2019-11-24  5:38   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 4/8] bpf, sockmap: Don't let child socket inherit psock or its ops on copy Jakub Sitnicki
2019-11-24  5:56   ` John Fastabend
2019-11-25 22:38   ` Martin Lau
2019-11-26 15:54     ` Jakub Sitnicki
2019-11-26 17:16       ` Martin Lau
2019-11-26 18:36         ` Jakub Sitnicki
     [not found]           ` <87sglsfdda.fsf@cloudflare.com>
2019-12-11 17:20             ` Martin Lau
2019-12-12 11:27               ` Jakub Sitnicki
2019-12-12 19:23                 ` Martin Lau
2019-12-17 15:06                   ` Jakub Sitnicki
2019-11-26 18:43         ` John Fastabend
2019-11-27 22:18           ` Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 5/8] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2019-11-24  5:57   ` John Fastabend
2019-11-25  1:24   ` Alexei Starovoitov [this message]
2019-11-25  4:17     ` John Fastabend
2019-11-25 10:40       ` Jakub Sitnicki
2019-11-25 22:07         ` Martin Lau
2019-11-26 14:30           ` Jakub Sitnicki
2019-11-26 19:03             ` Martin Lau
2019-11-27 21:34               ` Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 6/8] libbpf: Recognize SK_REUSEPORT programs from section name Jakub Sitnicki
2019-11-24  5:57   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 7/8] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2019-11-24  6:00   ` John Fastabend
2019-11-25 22:30   ` Martin Lau
2019-11-26 14:32     ` Jakub Sitnicki
2019-12-12 10:30     ` Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 8/8] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
2019-11-24  6:04   ` John Fastabend
2019-11-24  6:10 ` [PATCH bpf-next 0/8] Extend SOCKMAP to store " John Fastabend
2019-11-25  9:22   ` Jakub Sitnicki

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