mptcp: reset subflow when MP_FAIL doesn't respond

This patch adds a new msk->flags bit MPTCP_FAIL_NO_RESPONSE, then reuses
sk_timer to trigger a check if we have not received a response from the
peer after sending MP_FAIL. If the peer doesn't respond properly, reset
the subflow.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 971e843..14f448d 100644 (file)
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -287,6 +287,7 @@ void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq)
 {
        struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
        struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+       struct sock *s = (struct sock *)msk;
 
        pr_debug("fail_seq=%llu", fail_seq);
 
@@ -299,6 +300,13 @@ void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq)
                subflow->send_mp_fail = 1;
                MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILTX);
                subflow->send_infinite_map = 1;
+       } else if (s && inet_sk_state_load(s) != TCP_CLOSE) {
+               pr_debug("MP_FAIL response received");
+
+               mptcp_data_lock(s);
+               if (inet_sk_state_load(s) != TCP_CLOSE)
+                       sk_stop_timer(s, &s->sk_timer);
+               mptcp_data_unlock(s);
        }
 }
 

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index ea74122..a5d466e 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2169,10 +2169,38 @@ static void mptcp_retransmit_timer(struct timer_list *t)
        sock_put(sk);
 }
 
+static struct mptcp_subflow_context *
+mp_fail_response_expect_subflow(struct mptcp_sock *msk)
+{
+       struct mptcp_subflow_context *subflow, *ret = NULL;
+
+       mptcp_for_each_subflow(msk, subflow) {
+               if (READ_ONCE(subflow->mp_fail_response_expect)) {
+                       ret = subflow;
+                       break;
+               }
+       }
+
+       return ret;
+}
+
+static void mptcp_check_mp_fail_response(struct mptcp_sock *msk)
+{
+       struct mptcp_subflow_context *subflow;
+       struct sock *sk = (struct sock *)msk;
+
+       bh_lock_sock(sk);
+       subflow = mp_fail_response_expect_subflow(msk);
+       if (subflow)
+               __set_bit(MPTCP_FAIL_NO_RESPONSE, &msk->flags);
+       bh_unlock_sock(sk);
+}
+
 static void mptcp_timeout_timer(struct timer_list *t)
 {
        struct sock *sk = from_timer(sk, t, sk_timer);
 
+       mptcp_check_mp_fail_response(mptcp_sk(sk));
        mptcp_schedule_work(sk);
        sock_put(sk);
 }
@@ -2499,6 +2527,23 @@ reset_timer:
        mptcp_data_unlock(sk);
 }
 
+static void mptcp_mp_fail_no_response(struct mptcp_sock *msk)
+{
+       struct mptcp_subflow_context *subflow;
+       struct sock *ssk;
+       bool slow;
+
+       subflow = mp_fail_response_expect_subflow(msk);
+       if (subflow) {
+               pr_debug("MP_FAIL doesn't respond, reset the subflow");
+
+               ssk = mptcp_subflow_tcp_sock(subflow);
+               slow = lock_sock_fast(ssk);
+               mptcp_subflow_reset(ssk);
+               unlock_sock_fast(ssk, slow);
+       }
+}
+
 static void mptcp_worker(struct work_struct *work)
 {
        struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
@@ -2539,6 +2584,9 @@ static void mptcp_worker(struct work_struct *work)
        if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
                __mptcp_retrans(sk);
 
+       if (test_and_clear_bit(MPTCP_FAIL_NO_RESPONSE, &msk->flags))
+               mptcp_mp_fail_no_response(msk);
+
 unlock:
        release_sock(sk);
        sock_put(sk);

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index cc66c81..3a8740f 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -116,6 +116,7 @@
 #define MPTCP_WORK_EOF         3
 #define MPTCP_FALLBACK_DONE    4
 #define MPTCP_WORK_CLOSE_SUBFLOW 5
+#define MPTCP_FAIL_NO_RESPONSE 6
 
 /* MPTCP socket release cb flags */
 #define MPTCP_PUSH_PENDING     1

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ca2352a..75c824b 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -968,6 +968,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
 {
        struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
        bool csum_reqd = READ_ONCE(msk->csum_enabled);
+       struct sock *sk = (struct sock *)msk;
        struct mptcp_ext *mpext;
        struct sk_buff *skb;
        u16 data_len;
@@ -1009,6 +1010,12 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
                pr_debug("infinite mapping received");
                MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
                subflow->map_data_len = 0;
+               if (sk && inet_sk_state_load(sk) != TCP_CLOSE) {
+                       mptcp_data_lock(sk);
+                       if (inet_sk_state_load(sk) != TCP_CLOSE)
+                               sk_stop_timer(sk, &sk->sk_timer);
+                       mptcp_data_unlock(sk);
+               }
                return MAPPING_INVALID;
        }
 
@@ -1219,6 +1226,10 @@ fallback:
                                        sk_eat_skb(ssk, skb);
                        } else {
                                WRITE_ONCE(subflow->mp_fail_response_expect, true);
+                               /* The data lock is acquired in __mptcp_move_skbs() */
+                               sk_reset_timer((struct sock *)msk,
+                                              &((struct sock *)msk)->sk_timer,
+                                              jiffies + TCP_RTO_MAX);
                        }
                        WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_NODATA);
                        return true;