From: Martin Lau <kafai@fb.com>
To: Jakub Sitnicki <jakub@cloudflare.com>
Cc: "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"kernel-team@cloudflare.com" <kernel-team@cloudflare.com>,
John Fastabend <john.fastabend@gmail.com>
Subject: Re: [PATCH bpf-next 4/8] bpf, sockmap: Don't let child socket inherit psock or its ops on copy
Date: Mon, 25 Nov 2019 22:38:49 +0000 [thread overview]
Message-ID: <20191125223845.6t6xoqcwcqxuqbdf@kafai-mbp> (raw)
In-Reply-To: <20191123110751.6729-5-jakub@cloudflare.com>
On Sat, Nov 23, 2019 at 12:07:47PM +0100, Jakub Sitnicki wrote:
[ ... ]
> @@ -370,6 +378,11 @@ static inline void sk_psock_restore_proto(struct sock *sk,
> sk->sk_prot = psock->sk_proto;
> psock->sk_proto = NULL;
> }
> +
> + if (psock->icsk_af_ops) {
> + icsk->icsk_af_ops = psock->icsk_af_ops;
> + psock->icsk_af_ops = NULL;
> + }
> }
[ ... ]
> +static struct sock *tcp_bpf_syn_recv_sock(const struct sock *sk,
> + struct sk_buff *skb,
> + struct request_sock *req,
> + struct dst_entry *dst,
> + struct request_sock *req_unhash,
> + bool *own_req)
> +{
> + const struct inet_connection_sock_af_ops *ops;
> + void (*write_space)(struct sock *sk);
> + struct sk_psock *psock;
> + struct proto *proto;
> + struct sock *child;
> +
> + rcu_read_lock();
> + psock = sk_psock(sk);
> + if (likely(psock)) {
> + proto = psock->sk_proto;
> + write_space = psock->saved_write_space;
> + ops = psock->icsk_af_ops;
It is not immediately clear to me what ensure
ops is not NULL here.
It is likely I missed something. A short comment would
be very useful here.
> + } else {
> + ops = inet_csk(sk)->icsk_af_ops;
> + }
> + rcu_read_unlock();
> +
> + child = ops->syn_recv_sock(sk, skb, req, dst, req_unhash, own_req);
> +
> + /* Child must not inherit psock or its ops. */
> + if (child && psock) {
> + rcu_assign_sk_user_data(child, NULL);
> + child->sk_prot = proto;
> + child->sk_write_space = write_space;
> +
> + /* v4-mapped sockets don't inherit parent ops. Don't restore. */
> + if (inet_csk(child)->icsk_af_ops == inet_csk(sk)->icsk_af_ops)
> + inet_csk(child)->icsk_af_ops = ops;
> + }
> + return child;
> +}
> +
> enum {
> TCP_BPF_IPV4,
> TCP_BPF_IPV6,
> @@ -597,6 +642,7 @@ enum {
> static struct proto *tcpv6_prot_saved __read_mostly;
> static DEFINE_SPINLOCK(tcpv6_prot_lock);
> static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS];
> +static struct inet_connection_sock_af_ops tcp_bpf_af_ops[TCP_BPF_NUM_PROTS];
>
> static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
> struct proto *base)
> @@ -612,13 +658,23 @@ static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
> prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage;
> }
>
> -static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops)
> +static void tcp_bpf_rebuild_af_ops(struct inet_connection_sock_af_ops *ops,
> + const struct inet_connection_sock_af_ops *base)
> +{
> + *ops = *base;
> + ops->syn_recv_sock = tcp_bpf_syn_recv_sock;
> +}
> +
> +static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops,
> + const struct inet_connection_sock_af_ops *af_ops)
> {
> if (sk->sk_family == AF_INET6 &&
> unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) {
> spin_lock_bh(&tcpv6_prot_lock);
> if (likely(ops != tcpv6_prot_saved)) {
> tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops);
> + tcp_bpf_rebuild_af_ops(&tcp_bpf_af_ops[TCP_BPF_IPV6],
> + af_ops);
> smp_store_release(&tcpv6_prot_saved, ops);
> }
> spin_unlock_bh(&tcpv6_prot_lock);
> @@ -628,6 +684,8 @@ static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops)
> static int __init tcp_bpf_v4_build_proto(void)
> {
> tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot);
> + tcp_bpf_rebuild_af_ops(&tcp_bpf_af_ops[TCP_BPF_IPV4], &ipv4_specific);
> +
> return 0;
> }
> core_initcall(tcp_bpf_v4_build_proto);
> @@ -637,7 +695,8 @@ static void tcp_bpf_update_sk_prot(struct sock *sk, struct sk_psock *psock)
> int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
> int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
>
> - sk_psock_update_proto(sk, psock, &tcp_bpf_prots[family][config]);
> + sk_psock_update_proto(sk, psock, &tcp_bpf_prots[family][config],
> + &tcp_bpf_af_ops[family]);
> }
>
> static void tcp_bpf_reinit_sk_prot(struct sock *sk, struct sk_psock *psock)
> @@ -677,6 +736,7 @@ void tcp_bpf_reinit(struct sock *sk)
>
> int tcp_bpf_init(struct sock *sk)
> {
> + struct inet_connection_sock *icsk = inet_csk(sk);
> struct proto *ops = READ_ONCE(sk->sk_prot);
> struct sk_psock *psock;
>
> @@ -689,7 +749,7 @@ int tcp_bpf_init(struct sock *sk)
> rcu_read_unlock();
> return -EINVAL;
> }
> - tcp_bpf_check_v6_needs_rebuild(sk, ops);
> + tcp_bpf_check_v6_needs_rebuild(sk, ops, icsk->icsk_af_ops);
> tcp_bpf_update_sk_prot(sk, psock);
> rcu_read_unlock();
> return 0;
> --
> 2.20.1
>
next prev parent reply other threads:[~2019-11-25 22:38 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191125223845.6t6xoqcwcqxuqbdf@kafai-mbp \
--to=kafai@fb.com \
--cc=bpf@vger.kernel.org \
--cc=jakub@cloudflare.com \
--cc=john.fastabend@gmail.com \
--cc=kernel-team@cloudflare.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).