Merge branch 'mptcp-simplify-mptcp_accept'
Paolo Abeni says:
====================
mptcp: simplify mptcp_accept()
Currently we allocate the MPTCP master socket at accept time.
The above makes mptcp_accept() quite complex, and requires checks is several
places for NULL MPTCP master socket.
These series simplify the MPTCP accept implementation, moving the master socket
allocation at syn-ack time, so that we drop unneeded checks with the follow-up
patch.
v1 -> v2:
- rebased on top of 2398e3991b
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
commit
a79c838fb0
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@ -336,7 +336,6 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
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unsigned int ack_size;
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bool ret = false;
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bool can_ack;
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u64 ack_seq;
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u8 tcp_fin;
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if (skb) {
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@ -368,16 +367,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
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can_ack = true;
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opts->ext_copy.use_ack = 0;
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msk = mptcp_sk(subflow->conn);
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if (likely(msk && READ_ONCE(msk->can_ack))) {
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ack_seq = msk->ack_seq;
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} else if (subflow->can_ack) {
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mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
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ack_seq++;
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} else {
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can_ack = false;
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}
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if (unlikely(!can_ack)) {
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if (!READ_ONCE(msk->can_ack)) {
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*size = ALIGN(dss_size, 4);
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return ret;
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}
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@ -390,7 +380,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
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dss_size += ack_size;
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opts->ext_copy.data_ack = ack_seq;
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opts->ext_copy.data_ack = msk->ack_seq;
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opts->ext_copy.ack64 = 1;
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opts->ext_copy.use_ack = 1;
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@ -820,9 +820,12 @@ static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
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}
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#endif
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static struct sock *mptcp_sk_clone_lock(const struct sock *sk)
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struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req)
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{
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struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
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struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
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struct mptcp_sock *msk;
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u64 ack_seq;
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if (!nsk)
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return NULL;
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@ -832,6 +835,36 @@ static struct sock *mptcp_sk_clone_lock(const struct sock *sk)
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inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
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#endif
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__mptcp_init_sock(nsk);
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msk = mptcp_sk(nsk);
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msk->local_key = subflow_req->local_key;
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msk->token = subflow_req->token;
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msk->subflow = NULL;
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if (unlikely(mptcp_token_new_accept(subflow_req->token, nsk))) {
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bh_unlock_sock(nsk);
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/* we can't call into mptcp_close() here - possible BH context
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* free the sock directly
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*/
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nsk->sk_prot->destroy(nsk);
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sk_free(nsk);
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return NULL;
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}
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msk->write_seq = subflow_req->idsn + 1;
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if (subflow_req->remote_key_valid) {
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msk->can_ack = true;
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msk->remote_key = subflow_req->remote_key;
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mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
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ack_seq++;
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msk->ack_seq = ack_seq;
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}
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bh_unlock_sock(nsk);
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/* keep a single reference */
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__sock_put(nsk);
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return nsk;
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}
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@ -859,40 +892,26 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
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struct mptcp_subflow_context *subflow;
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struct sock *new_mptcp_sock;
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struct sock *ssk = newsk;
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u64 ack_seq;
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subflow = mptcp_subflow_ctx(newsk);
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lock_sock(sk);
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new_mptcp_sock = subflow->conn;
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/* is_mptcp should be false if subflow->conn is missing, see
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* subflow_syn_recv_sock()
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*/
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if (WARN_ON_ONCE(!new_mptcp_sock)) {
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tcp_sk(newsk)->is_mptcp = 0;
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return newsk;
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}
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/* acquire the 2nd reference for the owning socket */
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sock_hold(new_mptcp_sock);
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local_bh_disable();
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new_mptcp_sock = mptcp_sk_clone_lock(sk);
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if (!new_mptcp_sock) {
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*err = -ENOBUFS;
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local_bh_enable();
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release_sock(sk);
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mptcp_subflow_shutdown(newsk, SHUT_RDWR + 1, 0, 0);
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tcp_close(newsk, 0);
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return NULL;
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}
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__mptcp_init_sock(new_mptcp_sock);
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bh_lock_sock(new_mptcp_sock);
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msk = mptcp_sk(new_mptcp_sock);
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msk->local_key = subflow->local_key;
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msk->token = subflow->token;
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msk->subflow = NULL;
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msk->first = newsk;
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mptcp_token_update_accept(newsk, new_mptcp_sock);
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msk->write_seq = subflow->idsn + 1;
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if (subflow->can_ack) {
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msk->can_ack = true;
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msk->remote_key = subflow->remote_key;
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mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
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ack_seq++;
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msk->ack_seq = ack_seq;
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}
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newsk = new_mptcp_sock;
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mptcp_copy_inaddrs(newsk, ssk);
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list_add(&subflow->node, &msk->conn_list);
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@ -903,18 +922,6 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
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inet_sk_state_store(new_mptcp_sock, TCP_SYN_RECV);
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bh_unlock_sock(new_mptcp_sock);
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local_bh_enable();
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release_sock(sk);
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/* the subflow can already receive packet, avoid racing with
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* the receive path and process the pending ones
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*/
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lock_sock(ssk);
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subflow->rel_write_seq = 1;
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subflow->tcp_sock = ssk;
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subflow->conn = new_mptcp_sock;
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if (unlikely(!skb_queue_empty(&ssk->sk_receive_queue)))
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mptcp_subflow_data_available(ssk);
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release_sock(ssk);
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}
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return newsk;
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@ -193,6 +193,7 @@ void mptcp_proto_init(void);
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int mptcp_proto_v6_init(void);
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#endif
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struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req);
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void mptcp_get_options(const struct sk_buff *skb,
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struct tcp_options_received *opt_rx);
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@ -202,8 +203,7 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk);
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int mptcp_token_new_request(struct request_sock *req);
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void mptcp_token_destroy_request(u32 token);
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int mptcp_token_new_connect(struct sock *sk);
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int mptcp_token_new_accept(u32 token);
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void mptcp_token_update_accept(struct sock *sk, struct sock *conn);
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int mptcp_token_new_accept(u32 token, struct sock *conn);
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void mptcp_token_destroy(u32 token);
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void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
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@ -112,7 +112,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
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subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
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if (subflow->conn && !subflow->conn_finished) {
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if (!subflow->conn_finished) {
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pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
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subflow->remote_key);
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mptcp_finish_connect(sk);
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@ -182,6 +182,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
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struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
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struct mptcp_subflow_request_sock *subflow_req;
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struct tcp_options_received opt_rx;
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struct sock *new_msk = NULL;
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struct sock *child;
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pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
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@ -197,7 +198,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
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* out-of-order pkt, which will not carry the MP_CAPABLE
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* opt even on mptcp enabled paths
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*/
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goto create_child;
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goto create_msk;
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}
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opt_rx.mptcp.mp_capable = 0;
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@ -207,7 +208,13 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
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subflow_req->remote_key_valid = 1;
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} else {
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subflow_req->mp_capable = 0;
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goto create_child;
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}
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create_msk:
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new_msk = mptcp_sk_clone(listener->conn, req);
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if (!new_msk)
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subflow_req->mp_capable = 0;
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}
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create_child:
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@ -221,22 +228,22 @@ create_child:
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* handshake
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*/
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if (!ctx)
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return child;
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goto out;
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if (ctx->mp_capable) {
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if (mptcp_token_new_accept(ctx->token))
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goto close_child;
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/* new mpc subflow takes ownership of the newly
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* created mptcp socket
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*/
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ctx->conn = new_msk;
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new_msk = NULL;
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}
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}
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out:
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/* dispose of the left over mptcp master, if any */
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if (unlikely(new_msk))
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sock_put(new_msk);
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return child;
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close_child:
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pr_debug("closing child socket");
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tcp_send_active_reset(child, GFP_ATOMIC);
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inet_csk_prepare_forced_close(child);
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tcp_done(child);
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return NULL;
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}
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static struct inet_connection_sock_af_ops subflow_specific;
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@ -432,9 +439,6 @@ static bool subflow_check_data_avail(struct sock *ssk)
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if (subflow->data_avail)
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return true;
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if (!subflow->conn)
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return false;
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msk = mptcp_sk(subflow->conn);
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for (;;) {
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u32 map_remaining;
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@ -554,11 +558,10 @@ static void subflow_data_ready(struct sock *sk)
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
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struct sock *parent = subflow->conn;
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if (!parent || !subflow->mp_capable) {
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if (!subflow->mp_capable) {
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subflow->tcp_data_ready(sk);
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if (parent)
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parent->sk_data_ready(parent);
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parent->sk_data_ready(parent);
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return;
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}
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@ -572,7 +575,7 @@ static void subflow_write_space(struct sock *sk)
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struct sock *parent = subflow->conn;
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sk_stream_write_space(sk);
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if (parent && sk_stream_is_writeable(sk)) {
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if (sk_stream_is_writeable(sk)) {
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set_bit(MPTCP_SEND_SPACE, &mptcp_sk(parent)->flags);
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smp_mb__after_atomic();
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/* set SEND_SPACE before sk_stream_write_space clears NOSPACE */
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@ -687,7 +690,7 @@ static bool subflow_is_done(const struct sock *sk)
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static void subflow_state_change(struct sock *sk)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
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struct sock *parent = READ_ONCE(subflow->conn);
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struct sock *parent = subflow->conn;
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__subflow_state_change(sk);
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@ -695,10 +698,10 @@ static void subflow_state_change(struct sock *sk)
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* a fin packet carrying a DSS can be unnoticed if we don't trigger
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* the data available machinery here.
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*/
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if (parent && subflow->mp_capable && mptcp_subflow_data_available(sk))
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if (subflow->mp_capable && mptcp_subflow_data_available(sk))
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mptcp_data_ready(parent, sk);
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if (parent && !(parent->sk_shutdown & RCV_SHUTDOWN) &&
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if (!(parent->sk_shutdown & RCV_SHUTDOWN) &&
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!subflow->rx_eof && subflow_is_done(sk)) {
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subflow->rx_eof = 1;
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parent->sk_shutdown |= RCV_SHUTDOWN;
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@ -793,6 +796,9 @@ static void subflow_ulp_clone(const struct request_sock *req,
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new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
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new_ctx->tcp_state_change = old_ctx->tcp_state_change;
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new_ctx->tcp_write_space = old_ctx->tcp_write_space;
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new_ctx->rel_write_seq = 1;
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new_ctx->tcp_sock = newsk;
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new_ctx->mp_capable = 1;
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new_ctx->fourth_ack = subflow_req->remote_key_valid;
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new_ctx->can_ack = subflow_req->remote_key_valid;
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@ -128,45 +128,18 @@ int mptcp_token_new_connect(struct sock *sk)
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*
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* Called when a SYN packet creates a new logical connection, i.e.
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* is not a join request.
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*
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* We don't have an mptcp socket yet at that point.
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* This is paired with mptcp_token_update_accept, called on accept().
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*/
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int mptcp_token_new_accept(u32 token)
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int mptcp_token_new_accept(u32 token, struct sock *conn)
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{
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int err;
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spin_lock_bh(&token_tree_lock);
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err = radix_tree_insert(&token_tree, token, &token_used);
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err = radix_tree_insert(&token_tree, token, conn);
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spin_unlock_bh(&token_tree_lock);
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return err;
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}
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/**
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* mptcp_token_update_accept - update token to map to mptcp socket
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* @conn: the new struct mptcp_sock
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* @sk: the initial subflow for this mptcp socket
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*
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* Called when the first mptcp socket is created on accept to
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* refresh the dummy mapping (done to reserve the token) with
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* the mptcp_socket structure that wasn't allocated before.
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*/
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void mptcp_token_update_accept(struct sock *sk, struct sock *conn)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
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void __rcu **slot;
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spin_lock_bh(&token_tree_lock);
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slot = radix_tree_lookup_slot(&token_tree, subflow->token);
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WARN_ON_ONCE(!slot);
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if (slot) {
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WARN_ON_ONCE(rcu_access_pointer(*slot) != &token_used);
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radix_tree_replace_slot(&token_tree, slot, conn);
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}
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spin_unlock_bh(&token_tree_lock);
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}
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/**
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* mptcp_token_destroy_request - remove mptcp connection/token
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* @token - token of mptcp connection to remove
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