This is a note to let you know that I've just added the patch titled
mptcp: simplify subflow_syn_recv_sock()
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mptcp-simplify-subflow_syn_recv_sock.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1ba1b5bc57c79597fe8b53f8548863f082d86088
Author: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Mon Mar 27 12:22:22 2023 +0200
mptcp: simplify subflow_syn_recv_sock()
[ Upstream commit a88d0092b24b8cddce57fe0e88e60a9e29e0b515 ]
Postpone the msk cloning to the child process creation
so that we can avoid a bunch of conditionals.
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/61
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
Signed-off-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 7e8b88ec35ee ("mptcp: consolidate passive msk socket initialization")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 8a6bd2782dc97..3b8abd79bfbd5 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -695,14 +695,6 @@ static bool subflow_hmac_valid(const struct request_sock *req,
return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);
}
-static void mptcp_force_close(struct sock *sk)
-{
- /* the msk is not yet exposed to user-space, and refcount is 2 */
- inet_sk_state_store(sk, TCP_CLOSE);
- sk_common_release(sk);
- sock_put(sk);
-}
-
static void subflow_ulp_fallback(struct sock *sk,
struct mptcp_subflow_context *old_ctx)
{
@@ -757,7 +749,6 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
struct mptcp_subflow_request_sock *subflow_req;
struct mptcp_options_received mp_opt;
bool fallback, fallback_is_fatal;
- struct sock *new_msk = NULL;
struct mptcp_sock *owner;
struct sock *child;
@@ -786,14 +777,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
* options.
*/
mptcp_get_options(skb, &mp_opt);
- if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) {
+ if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC))
fallback = true;
- goto create_child;
- }
- new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);
- if (!new_msk)
- fallback = true;
} else if (subflow_req->mp_join) {
mptcp_get_options(skb, &mp_opt);
if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ) ||
@@ -822,21 +808,23 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
goto dispose_child;
}
-
- mptcp_subflow_drop_ctx(child);
- goto out;
+ goto fallback;
}
/* ssk inherits options of listener sk */
ctx->setsockopt_seq = listener->setsockopt_seq;
if (ctx->mp_capable) {
- owner = mptcp_sk(new_msk);
+ ctx->conn = mptcp_sk_clone(listener->conn, &mp_opt, req);
+ if (!ctx->conn)
+ goto fallback;
+
+ owner = mptcp_sk(ctx->conn);
/* this can't race with mptcp_close(), as the msk is
* not yet exposted to user-space
*/
- inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);
+ inet_sk_state_store(ctx->conn, TCP_ESTABLISHED);
/* record the newly created socket as the first msk
* subflow, but don't link it yet into conn_list
@@ -846,11 +834,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
/* new mpc subflow takes ownership of the newly
* created mptcp socket
*/
- mptcp_sk(new_msk)->setsockopt_seq = ctx->setsockopt_seq;
+ owner->setsockopt_seq = ctx->setsockopt_seq;
mptcp_pm_new_connection(owner, child, 1);
mptcp_token_accept(subflow_req, owner);
- ctx->conn = new_msk;
- new_msk = NULL;
/* set msk addresses early to ensure mptcp_pm_get_local_id()
* uses the correct data
@@ -900,11 +886,6 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
}
}
-out:
- /* dispose of the left over mptcp master, if any */
- if (unlikely(new_msk))
- mptcp_force_close(new_msk);
-
/* check for expected invariant - should never trigger, just help
* catching eariler subtle bugs
*/
@@ -922,6 +903,10 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
/* The last child reference will be released by the caller */
return child;
+
+fallback:
+ mptcp_subflow_drop_ctx(child);
+ return child;
}
static struct inet_connection_sock_af_ops subflow_specific __ro_after_init;
