From: Paolo Abeni <pabeni@xxxxxxxxxx> 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> --- net/mptcp/subflow.c | 41 +++++++++++++---------------------------- 1 file changed, 13 insertions(+), 28 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index a11f4c525e01..33dd27765116 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -696,14 +696,6 @@ 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) { @@ -755,7 +747,6 @@ 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; @@ -784,14 +775,9 @@ 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) || @@ -820,21 +806,23 @@ 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 @@ -844,11 +832,9 @@ 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 @@ -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 * 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 */ return child; + +fallback: + mptcp_subflow_drop_ctx(child); + return child; } static struct inet_connection_sock_af_ops subflow_specific __ro_after_init; -- 2.39.2
