diff mbox series

[net-next,5/7] mptcp: reset subflow when MP_FAIL doesn't respond

Message ID 20220426215717.129506-6-mathew.j.martineau@linux.intel.com (mailing list archive)
State Accepted
Commit 49fa1919d6bcdcf3cf3d080c1943f537f6ed5e70
Delegated to: Netdev Maintainers
Headers show
Series mptcp: Timeout for MP_FAIL response | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 11 this patch: 11
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 5 this patch: 5
netdev/checkpatch warning WARNING: line length of 86 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mat Martineau April 26, 2022, 9:57 p.m. UTC 
From: Geliang Tang <geliang.tang@suse.com>

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>
---
 net/mptcp/pm.c       |  8 ++++++++
 net/mptcp/protocol.c | 48 ++++++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.h |  1 +
 net/mptcp/subflow.c  | 11 ++++++++++
 4 files changed, 68 insertions(+)
diff mbox series

Patch

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 971e843a304c..14f448d82bb2 100644
--- 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 ea74122065f1..a5d466e6b538 100644
--- 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 @@  static void __mptcp_retrans(struct sock *sk)
 	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 cc66c81a8fab..3a8740fef918 100644
--- 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 ca2352ad20d4..75c824b67ca9 100644
--- 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 @@  static bool subflow_check_data_avail(struct sock *ssk)
 					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;