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mptcp: simplify subflow_syn_recv_sock()

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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@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2023-03-27 12:22:22 +02:00 committed by David S. Miller
parent 2bb9a37f0e
commit a88d0092b2
1 changed files with 13 additions and 28 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

41
net/mptcp/subflow.c
View file

@ -696,14 +696,6 @@ static bool subflow_hmac_valid(const struct request_sock *req,
return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN); 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, static void subflow_ulp_fallback(struct sock *sk,
struct mptcp_subflow_context *old_ctx) struct mptcp_subflow_context *old_ctx)
{ {
@ -755,7 +747,6 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
struct mptcp_subflow_request_sock *subflow_req; struct mptcp_subflow_request_sock *subflow_req;
struct mptcp_options_received mp_opt; struct mptcp_options_received mp_opt;
bool fallback, fallback_is_fatal; bool fallback, fallback_is_fatal;
struct sock *new_msk = NULL;
struct mptcp_sock *owner; struct mptcp_sock *owner;
struct sock *child; struct sock *child;
@ -784,14 +775,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
* options. * options.
*/ */
mptcp_get_options(skb, &mp_opt); mptcp_get_options(skb, &mp_opt);
if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) { if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC))
fallback = true; 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) { } else if (subflow_req->mp_join) {
mptcp_get_options(skb, &mp_opt); mptcp_get_options(skb, &mp_opt);
if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ) || if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ) ||
@ -820,21 +806,23 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP); subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
goto dispose_child; goto dispose_child;
} }
goto fallback;
mptcp_subflow_drop_ctx(child);
goto out;
} }
/* ssk inherits options of listener sk */ /* ssk inherits options of listener sk */
ctx->setsockopt_seq = listener->setsockopt_seq; ctx->setsockopt_seq = listener->setsockopt_seq;
if (ctx->mp_capable) { 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 /* this can't race with mptcp_close(), as the msk is
* not yet exposted to user-space * 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 /* record the newly created socket as the first msk
* subflow, but don't link it yet into conn_list * subflow, but don't link it yet into conn_list
@ -844,11 +832,9 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
/* new mpc subflow takes ownership of the newly /* new mpc subflow takes ownership of the newly
* created mptcp socket * 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_pm_new_connection(owner, child, 1);
mptcp_token_accept(subflow_req, owner); mptcp_token_accept(subflow_req, owner);
ctx->conn = new_msk;
new_msk = NULL;
/* set msk addresses early to ensure mptcp_pm_get_local_id() /* set msk addresses early to ensure mptcp_pm_get_local_id()
* uses the correct data * uses the correct data
@ -898,11 +884,6 @@ 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 /* check for expected invariant - should never trigger, just help
* catching eariler subtle bugs * catching eariler subtle bugs
*/ */
@ -920,6 +901,10 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
/* The last child reference will be released by the caller */ /* The last child reference will be released by the caller */
return child; return child;
fallback:
mptcp_subflow_drop_ctx(child);
return child;
} }
static struct inet_connection_sock_af_ops subflow_specific __ro_after_init; static struct inet_connection_sock_af_ops subflow_specific __ro_after_init;