net: mptcp: improve fallback to TCP

[linux-2.6-microblaze.git] / net / mptcp / subflow.c

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 3838a0b..cb8a42f 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -32,12 +32,9 @@ static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
 static int subflow_rebuild_header(struct sock *sk)
 {
        struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
-       int local_id, err = 0;
+       int local_id;
 
-       if (subflow->request_mptcp && !subflow->token) {
-               pr_debug("subflow=%p", sk);
-               err = mptcp_token_new_connect(sk);
-       } else if (subflow->request_join && !subflow->local_nonce) {
+       if (subflow->request_join && !subflow->local_nonce) {
                struct mptcp_sock *msk = (struct mptcp_sock *)subflow->conn;
 
                pr_debug("subflow=%p", sk);
@@ -57,9 +54,6 @@ static int subflow_rebuild_header(struct sock *sk)
        }
 
 out:
-       if (err)
-               return err;
-
        return subflow->icsk_af_ops->rebuild_header(sk);
 }
 
@@ -72,8 +66,7 @@ static void subflow_req_destructor(struct request_sock *req)
        if (subflow_req->msk)
                sock_put((struct sock *)subflow_req->msk);
 
-       if (subflow_req->mp_capable)
-               mptcp_token_destroy_request(subflow_req->token);
+       mptcp_token_destroy_request(req);
        tcp_request_sock_ops.destructor(req);
 }
 
@@ -135,6 +128,7 @@ static void subflow_init_req(struct request_sock *req,
        subflow_req->mp_capable = 0;
        subflow_req->mp_join = 0;
        subflow_req->msk = NULL;
+       mptcp_token_init_request(req);
 
 #ifdef CONFIG_TCP_MD5SIG
        /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
@@ -222,7 +216,6 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
        struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
        struct mptcp_options_received mp_opt;
        struct sock *parent = subflow->conn;
-       struct tcp_sock *tp = tcp_sk(sk);
 
        subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
 
@@ -236,6 +229,8 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
                return;
 
        subflow->conn_finished = 1;
+       subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
+       pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset);
 
        mptcp_get_options(skb, &mp_opt);
        if (subflow->request_mptcp && mp_opt.mp_capable) {
@@ -250,22 +245,21 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
                subflow->remote_nonce = mp_opt.nonce;
                pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
                         subflow->thmac, subflow->remote_nonce);
-       } else if (subflow->request_mptcp) {
-               tp->is_mptcp = 0;
+       } else {
+               if (subflow->request_mptcp)
+                       MPTCP_INC_STATS(sock_net(sk),
+                                       MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
+               mptcp_do_fallback(sk);
+               pr_fallback(mptcp_sk(subflow->conn));
        }
 
-       if (!tp->is_mptcp)
+       if (mptcp_check_fallback(sk))
                return;
 
        if (subflow->mp_capable) {
                pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
                         subflow->remote_key);
                mptcp_finish_connect(sk);
-
-               if (skb) {
-                       pr_debug("synack seq=%u", TCP_SKB_CB(skb)->seq);
-                       subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
-               }
        } else if (subflow->mp_join) {
                u8 hmac[SHA256_DIGEST_SIZE];
 
@@ -285,9 +279,6 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 
                memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);
 
-               if (skb)
-                       subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
-
                if (!mptcp_finish_join(sk))
                        goto do_reset;
 
@@ -386,7 +377,7 @@ static void mptcp_sock_destruct(struct sock *sk)
                sock_orphan(sk);
        }
 
-       mptcp_token_destroy(mptcp_sk(sk)->token);
+       mptcp_token_destroy(mptcp_sk(sk));
        inet_sock_destruct(sk);
 }
 
@@ -505,6 +496,7 @@ create_child:
                         */
                        new_msk->sk_destruct = mptcp_sock_destruct;
                        mptcp_pm_new_connection(mptcp_sk(new_msk), 1);
+                       mptcp_token_accept(subflow_req, mptcp_sk(new_msk));
                        ctx->conn = new_msk;
                        new_msk = NULL;
 
@@ -562,7 +554,8 @@ enum mapping_status {
        MAPPING_OK,
        MAPPING_INVALID,
        MAPPING_EMPTY,
-       MAPPING_DATA_FIN
+       MAPPING_DATA_FIN,
+       MAPPING_DUMMY
 };
 
 static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
@@ -626,6 +619,9 @@ static enum mapping_status get_mapping_status(struct sock *ssk)
        if (!skb)
                return MAPPING_EMPTY;
 
+       if (mptcp_check_fallback(ssk))
+               return MAPPING_DUMMY;
+
        mpext = mptcp_get_ext(skb);
        if (!mpext || !mpext->use_map) {
                if (!subflow->map_valid && !skb->len) {
@@ -767,6 +763,16 @@ static bool subflow_check_data_avail(struct sock *ssk)
                        ssk->sk_err = EBADMSG;
                        goto fatal;
                }
+               if (status == MAPPING_DUMMY) {
+                       __mptcp_do_fallback(msk);
+                       skb = skb_peek(&ssk->sk_receive_queue);
+                       subflow->map_valid = 1;
+                       subflow->map_seq = READ_ONCE(msk->ack_seq);
+                       subflow->map_data_len = skb->len;
+                       subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -
+                                                  subflow->ssn_offset;
+                       return true;
+               }
 
                if (status != MAPPING_OK)
                        return false;
@@ -890,14 +896,18 @@ static void subflow_data_ready(struct sock *sk)
 {
        struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
        struct sock *parent = subflow->conn;
+       struct mptcp_sock *msk;
 
-       if (!subflow->mp_capable && !subflow->mp_join) {
-               subflow->tcp_data_ready(sk);
-
+       msk = mptcp_sk(parent);
+       if (inet_sk_state_load(sk) == TCP_LISTEN) {
+               set_bit(MPTCP_DATA_READY, &msk->flags);
                parent->sk_data_ready(parent);
                return;
        }
 
+       WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
+                    !subflow->mp_join);
+
        if (mptcp_subflow_data_available(sk))
                mptcp_data_ready(parent, sk);
 }
@@ -1122,7 +1132,7 @@ static void subflow_state_change(struct sock *sk)
         * a fin packet carrying a DSS can be unnoticed if we don't trigger
         * the data available machinery here.
         */
-       if (subflow->mp_capable && mptcp_subflow_data_available(sk))
+       if (mptcp_subflow_data_available(sk))
                mptcp_data_ready(parent, sk);
 
        if (!(parent->sk_shutdown & RCV_SHUTDOWN) &&
@@ -1255,7 +1265,7 @@ static int subflow_ops_init(struct request_sock_ops *subflow_ops)
        return 0;
 }
 
-void mptcp_subflow_init(void)
+void __init mptcp_subflow_init(void)
 {
        subflow_request_sock_ops = tcp_request_sock_ops;
        if (subflow_ops_init(&subflow_request_sock_ops) != 0)