[PATCH v2 0/4] mptcp: fix conflicts when using pm.add_signal in ADD_ADDR/echo and RM_ADDR process

[PATCH v2 0/4] mptcp: fix conflicts when using pm.add_signal in ADD_ADDR/echo and RM_ADDR process

[Yonglong Li]

fix issue: ADD_ADDR and RM_ADDR use pm.add_signal to mark event, so 
in some case pm.add_signal will be flush when ADD_ADDR/RM_ADDR in 
process.

fix issue: if ADD_ADDR and ADD_ADDR-echo process at the same time, 
only one event can write pm.add_signal. so ADD_ADDR will process 
after add_timer timeout or ADD_ADDR-echo will not be process.

Patch 1 fix ADD_ADDR and RM_ADDR maybe clear addr_signal each other.

Patch 2 and 3 deal ADD_ADDR and ADD_ADDR-echo with separately to fix 
conflicts in using pm.addr_signal porcess.

Patch 4 MPTCP_ADD_ADDR_IPV6 and MPTCP_ADD_ADDR_PORT is not necessary.

v1->v2:
 - remove READ_ONCE under the pm spin lock.

Yonglong Li (4):
  mptcp: fix ADD_ADDR and RM_ADDR maybe flush addr_signal each other
  mptcp: make MPTCP_ADD_ADDR_SIGNAL and MPTCP_ADD_ADDR_ECHO separate
  mptcp: build ADD_ADDR/echo-ADD_ADDR option according pm.add_signal
  mptcp: remove MPTCP_ADD_ADDR_IPV6 and MPTCP_ADD_ADDR_PORT

 include/net/mptcp.h    |   1 +
 net/mptcp/options.c    | 161 ++++++++++++++++++++++++++++++++-----------------
 net/mptcp/pm.c         |  53 +++++++---------
 net/mptcp/pm_netlink.c |  10 ++-
 net/mptcp/protocol.h   |  31 ++++------
 5 files changed, 147 insertions(+), 109 deletions(-)

-- 
1.8.3.1

[PATCH v2 1/4] mptcp: fix ADD_ADDR and RM_ADDR maybe flush addr_signal each other

[Yonglong Li]

ADD_ADDR share pm.addr_signal with RM_ADDR, so after RM_ADDR/ADD_ADDR
done we should not clean ADD_ADDR/RM_ADDR's addr_signal.

Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
---
 net/mptcp/pm.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 9d00fa6..74886a3 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -252,6 +252,7 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup)
 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 			      struct mptcp_addr_info *saddr, bool *echo, bool *port)
 {
+	u8 add_addr;
 	int ret = false;
 
 	spin_lock_bh(&msk->pm.lock);
@@ -267,7 +268,8 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 		goto out_unlock;
 
 	*saddr = msk->pm.local;
-	WRITE_ONCE(msk->pm.addr_signal, 0);
+	add_addr = msk->pm.addr_signal & BIT(MPTCP_RM_ADDR_SIGNAL);
+	WRITE_ONCE(msk->pm.addr_signal, add_addr);
 	ret = true;
 
 out_unlock:
@@ -278,6 +280,7 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 			     struct mptcp_rm_list *rm_list)
 {
+	u8 rm_addr;
 	int ret = false, len;
 
 	spin_lock_bh(&msk->pm.lock);
@@ -286,16 +289,17 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 	if (!mptcp_pm_should_rm_signal(msk))
 		goto out_unlock;
 
+	rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL);
 	len = mptcp_rm_addr_len(&msk->pm.rm_list_tx);
 	if (len < 0) {
-		WRITE_ONCE(msk->pm.addr_signal, 0);
+		WRITE_ONCE(msk->pm.addr_signal, rm_addr);
 		goto out_unlock;
 	}
 	if (remaining < len)
 		goto out_unlock;
 
 	*rm_list = msk->pm.rm_list_tx;
-	WRITE_ONCE(msk->pm.addr_signal, 0);
+	WRITE_ONCE(msk->pm.addr_signal, rm_addr);
 	ret = true;
 
 out_unlock:
-- 
1.8.3.1

[PATCH v2 2/4] mptcp: make MPTCP_ADD_ADDR_SIGNAL and MPTCP_ADD_ADDR_ECHO separate

[Yonglong Li]

MPTCP_ADD_ADDR_SIGNAL only for action of sending ADD_ADDR
MPTCP_ADD_ADDR_ECHO only for action of sending echo ADD_ADDR
add a mptcp_addr_info in struct mptcp_out_options for echo ADD_ADDR

to prepare for the next patch.

Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
---
 include/net/mptcp.h    |  1 +
 net/mptcp/pm.c         | 13 ++++++++-----
 net/mptcp/pm_netlink.c |  4 ++--
 net/mptcp/protocol.h   |  6 ++++++
 4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index d61bbbf..637e90b 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -62,6 +62,7 @@ struct mptcp_out_options {
 	u64 rcvr_key;
 	u64 ahmac;
 	struct mptcp_addr_info addr;
+	struct mptcp_addr_info remote;
 	struct mptcp_rm_list rm_list;
 	u8 join_id;
 	u8 backup;
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 74886a3..9966ed1 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -18,7 +18,7 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 {
 	u8 add_addr = READ_ONCE(msk->pm.addr_signal);
 
-	pr_debug("msk=%p, local_id=%d", msk, addr->id);
+	pr_debug("msk=%p, local_id=%d, echo:%d", msk, addr->id, echo);
 
 	lockdep_assert_held(&msk->pm.lock);
 
@@ -27,10 +27,13 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 		return -EINVAL;
 	}
 
-	msk->pm.local = *addr;
-	add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
-	if (echo)
+	if (echo) {
+		msk->pm.remote = *addr;
 		add_addr |= BIT(MPTCP_ADD_ADDR_ECHO);
+	} else {
+		msk->pm.local = *addr;
+		add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
+	}
 	if (addr->family == AF_INET6)
 		add_addr |= BIT(MPTCP_ADD_ADDR_IPV6);
 	if (addr->port)
@@ -214,7 +217,7 @@ void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
 
 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk)
 {
-	if (!mptcp_pm_should_add_signal(msk))
+	if (!mptcp_pm_should_add_signal_echo(msk))
 		return;
 
 	mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK);
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index c53e500..ae700bd 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -317,14 +317,14 @@ static void mptcp_pm_add_timer(struct timer_list *timer)
 	if (!entry->addr.id)
 		return;
 
-	if (mptcp_pm_should_add_signal(msk)) {
+	if (mptcp_pm_should_add_addr(msk)) {
 		sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
 		goto out;
 	}
 
 	spin_lock_bh(&msk->pm.lock);
 
-	if (!mptcp_pm_should_add_signal(msk)) {
+	if (!mptcp_pm_should_add_addr(msk)) {
 		pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
 		mptcp_pm_announce_addr(msk, &entry->addr, false);
 		mptcp_pm_add_addr_send_ack(msk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 6c2322e..d14d03e 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -708,6 +708,12 @@ void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
 
 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
 {
+	return READ_ONCE(msk->pm.addr_signal) &
+		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
+}
+
+static inline bool mptcp_pm_should_add_addr(struct mptcp_sock *msk)
+{
 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
 }
 
-- 
1.8.3.1

[PATCH v2 3/4] mptcp: build ADD_ADDR/echo-ADD_ADDR option according pm.add_signal

[Yonglong Li]

according MPTCP_ADD_ADDR_SIGNAL and MPTCP_ADD_ADDR_ECHO flag build
ADD_ADDR/echo-ADD_ADDR option

add a suboptions type OPTION_MPTCP_ADD_ECHO to mark as echo option

Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
---
 net/mptcp/options.c  | 161 +++++++++++++++++++++++++++++++++------------------
 net/mptcp/pm.c       |  32 ++++------
 net/mptcp/protocol.h |  13 +++--
 3 files changed, 124 insertions(+), 82 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 1aec016..8875ba4 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -655,43 +655,72 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *
 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
 	bool drop_other_suboptions = false;
 	unsigned int opt_size = *size;
-	bool echo;
-	bool port;
+	struct mptcp_addr_info remote;
+	struct mptcp_addr_info local;
+	int ret = false;
+	u8 add_addr;
 	int len;
 
-	if ((mptcp_pm_should_add_signal_ipv6(msk) ||
-	     mptcp_pm_should_add_signal_port(msk) ||
-	     mptcp_pm_should_add_signal_echo(msk)) &&
-	    skb && skb_is_tcp_pure_ack(skb)) {
-		pr_debug("drop other suboptions");
-		opts->suboptions = 0;
-		opts->ext_copy.use_ack = 0;
-		opts->ext_copy.use_map = 0;
-		remaining += opt_size;
-		drop_other_suboptions = true;
-	}
-
-	if (!mptcp_pm_should_add_signal(msk) ||
-	    !(mptcp_pm_add_addr_signal(msk, remaining, &opts->addr, &echo, &port)))
-		return false;
-
-	len = mptcp_add_addr_len(opts->addr.family, echo, port);
-	if (remaining < len)
-		return false;
-
-	*size = len;
-	if (drop_other_suboptions)
-		*size -= opt_size;
-	opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
-	if (!echo) {
+	if (!mptcp_pm_should_add_signal(msk))
+		goto out;
+
+	*size = 0;
+	mptcp_pm_add_addr_signal(msk, &local, &remote, &add_addr);
+	if (mptcp_pm_should_add_signal_echo(msk)) {
+		if (skb && skb_is_tcp_pure_ack(skb)) {
+			pr_debug("drop other suboptions");
+			opts->suboptions = 0;
+			opts->ext_copy.use_ack = 0;
+			opts->ext_copy.use_map = 0;
+			remaining += opt_size;
+			drop_other_suboptions = true;
+		}
+		len = mptcp_add_addr_len(remote.family, true, !!remote.port);
+		if (remaining < len && mptcp_pm_should_add_addr(msk))
+			goto add_addr;
+		else if (remaining < len)
+			goto out;
+		remaining -= len;
+		*size += len;
+		opts->remote = remote;
+		add_addr &= ~BIT(MPTCP_ADD_ADDR_ECHO);
+		opts->suboptions |= OPTION_MPTCP_ADD_ECHO;
+		pr_debug("addr_id=%d, echo=1, port=%d addr_signal:%x",
+			 opts->remote.id, ntohs(opts->remote.port), add_addr);
+	} else if (mptcp_pm_should_add_addr(msk)) {
+add_addr:
+		if ((local.family == AF_INET6 || local.port) && skb &&
+		    skb_is_tcp_pure_ack(skb)) {
+			pr_debug("drop other suboptions");
+			opts->suboptions = 0;
+			opts->ext_copy.use_ack = 0;
+			opts->ext_copy.use_map = 0;
+			remaining += opt_size;
+			drop_other_suboptions = true;
+		}
+		len = mptcp_add_addr_len(local.family, false, !!local.port);
+		if (remaining < len)
+			goto out;
+		*size += len;
+		opts->addr = local;
 		opts->ahmac = add_addr_generate_hmac(msk->local_key,
 						     msk->remote_key,
 						     &opts->addr);
+		opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
+		add_addr &= ~BIT(MPTCP_ADD_ADDR_SIGNAL);
+		pr_debug("addr_id=%d, ahmac=%llu, echo=0, port=%d, addr_signal:%x",
+			 opts->addr.id, opts->ahmac, ntohs(opts->addr.port), add_addr);
 	}
-	pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
-		 opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port));
 
-	return true;
+	if (drop_other_suboptions)
+		*size -= opt_size;
+	spin_lock_bh(&msk->pm.lock);
+	WRITE_ONCE(msk->pm.addr_signal, add_addr);
+	spin_unlock_bh(&msk->pm.lock);
+	ret = true;
+
+out:
+	return ret;
 }
 
 static bool mptcp_established_options_rm_addr(struct sock *sk,
@@ -1230,21 +1259,18 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 mp_capable_done:
 	if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
 		u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
-		u8 echo = MPTCP_ADDR_ECHO;
+		u8 echo = 0;
 
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 		if (opts->addr.family == AF_INET6)
 			len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
 #endif
 
+		len += sizeof(opts->ahmac);
+
 		if (opts->addr.port)
 			len += TCPOLEN_MPTCP_PORT_LEN;
 
-		if (opts->ahmac) {
-			len += sizeof(opts->ahmac);
-			echo = 0;
-		}
-
 		*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
 				      len, echo, opts->addr.id);
 		if (opts->addr.family == AF_INET) {
@@ -1259,30 +1285,55 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 #endif
 
 		if (!opts->addr.port) {
-			if (opts->ahmac) {
-				put_unaligned_be64(opts->ahmac, ptr);
-				ptr += 2;
-			}
+			put_unaligned_be64(opts->ahmac, ptr);
+			ptr += 2;
 		} else {
 			u16 port = ntohs(opts->addr.port);
+			u8 *bptr = (u8 *)ptr;
 
-			if (opts->ahmac) {
-				u8 *bptr = (u8 *)ptr;
+			put_unaligned_be16(port, bptr);
+			bptr += 2;
+			put_unaligned_be64(opts->ahmac, bptr);
+			bptr += 8;
+			put_unaligned_be16(TCPOPT_NOP << 8 |
+					   TCPOPT_NOP, bptr);
 
-				put_unaligned_be16(port, bptr);
-				bptr += 2;
-				put_unaligned_be64(opts->ahmac, bptr);
-				bptr += 8;
-				put_unaligned_be16(TCPOPT_NOP << 8 |
-						   TCPOPT_NOP, bptr);
+			ptr += 3;
+		}
+	}
 
-				ptr += 3;
-			} else {
-				put_unaligned_be32(port << 16 |
-						   TCPOPT_NOP << 8 |
-						   TCPOPT_NOP, ptr);
-				ptr += 1;
-			}
+	if (OPTION_MPTCP_ADD_ECHO & opts->suboptions) {
+		u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
+		u8 echo = MPTCP_ADDR_ECHO;
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+		if (opts->remote.family == AF_INET6)
+			len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
+#endif
+
+		if (opts->remote.port)
+			len += TCPOLEN_MPTCP_PORT_LEN;
+
+		*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+				      len, echo, opts->remote.id);
+		if (opts->remote.family == AF_INET) {
+			memcpy((u8 *)ptr, (u8 *)&opts->remote.addr.s_addr, 4);
+			ptr += 1;
+		}
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+		else if (opts->remote.family == AF_INET6) {
+			memcpy((u8 *)ptr, opts->remote.addr6.s6_addr, 16);
+			ptr += 4;
+		}
+#endif
+
+		if (opts->remote.port) {
+			u16 port = ntohs(opts->remote.port);
+
+			put_unaligned_be32(port << 16 |
+					   TCPOPT_NOP << 8 |
+					   TCPOPT_NOP, ptr);
+			ptr += 1;
 		}
 	}
 
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 9966ed1..6a5ee6da 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -22,7 +22,8 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 
 	lockdep_assert_held(&msk->pm.lock);
 
-	if (add_addr) {
+	if (add_addr &
+	    (echo ? BIT(MPTCP_ADD_ADDR_ECHO) : BIT(MPTCP_ADD_ADDR_SIGNAL))) {
 		pr_warn("addr_signal error, add_addr=%d", add_addr);
 		return -EINVAL;
 	}
@@ -252,32 +253,21 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup)
 
 /* path manager helpers */
 
-bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
-			      struct mptcp_addr_info *saddr, bool *echo, bool *port)
+bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, struct mptcp_addr_info *saddr,
+			      struct mptcp_addr_info *daddr, u8 *add_addr)
 {
-	u8 add_addr;
-	int ret = false;
-
 	spin_lock_bh(&msk->pm.lock);
 
-	/* double check after the lock is acquired */
-	if (!mptcp_pm_should_add_signal(msk))
-		goto out_unlock;
-
-	*echo = mptcp_pm_should_add_signal_echo(msk);
-	*port = mptcp_pm_should_add_signal_port(msk);
-
-	if (remaining < mptcp_add_addr_len(msk->pm.local.family, *echo, *port))
-		goto out_unlock;
-
 	*saddr = msk->pm.local;
-	add_addr = msk->pm.addr_signal & BIT(MPTCP_RM_ADDR_SIGNAL);
-	WRITE_ONCE(msk->pm.addr_signal, add_addr);
-	ret = true;
+	*daddr = msk->pm.remote;
+	*add_addr = msk->pm.addr_signal;
 
-out_unlock:
 	spin_unlock_bh(&msk->pm.lock);
-	return ret;
+
+	if ((mptcp_pm_should_add_signal_echo(msk)) && (mptcp_pm_should_add_addr(msk)))
+		mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK);
+
+	return true;
 }
 
 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index d14d03e..25056c3 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -22,10 +22,11 @@
 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
-#define OPTION_MPTCP_RM_ADDR	BIT(7)
-#define OPTION_MPTCP_FASTCLOSE	BIT(8)
-#define OPTION_MPTCP_PRIO	BIT(9)
-#define OPTION_MPTCP_RST	BIT(10)
+#define OPTION_MPTCP_ADD_ECHO	BIT(7)
+#define OPTION_MPTCP_RM_ADDR	BIT(8)
+#define OPTION_MPTCP_FASTCLOSE	BIT(9)
+#define OPTION_MPTCP_PRIO	BIT(10)
+#define OPTION_MPTCP_RST	BIT(11)
 
 /* MPTCP option subtypes */
 #define MPTCPOPT_MP_CAPABLE	0
@@ -760,8 +761,8 @@ static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
 }
 
-bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
-			      struct mptcp_addr_info *saddr, bool *echo, bool *port);
+bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, struct mptcp_addr_info *saddr,
+			      struct mptcp_addr_info *daddr, u8 *add_addr);
 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 			     struct mptcp_rm_list *rm_list);
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
-- 
1.8.3.1

[PATCH v2 4/4] mptcp: remove MPTCP_ADD_ADDR_IPV6 and MPTCP_ADD_ADDR_PORT

[Yonglong Li]

there not need MPTCP_ADD_ADDR_PORT and MPTCP_ADD_ADDR_PORT, we can
get these info from pm.addr or pm.remote

Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
---
 net/mptcp/pm.c         |  4 ----
 net/mptcp/pm_netlink.c |  6 ++----
 net/mptcp/protocol.h   | 12 ------------
 3 files changed, 2 insertions(+), 20 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 6a5ee6da..2d9ee3c 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -35,10 +35,6 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 		msk->pm.local = *addr;
 		add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
 	}
-	if (addr->family == AF_INET6)
-		add_addr |= BIT(MPTCP_ADD_ADDR_IPV6);
-	if (addr->port)
-		add_addr |= BIT(MPTCP_ADD_ADDR_PORT);
 	WRITE_ONCE(msk->pm.addr_signal, add_addr);
 	return 0;
 }
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index ae700bd..2e67eca 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -544,10 +544,8 @@ void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)
 		bool slow;
 
 		spin_unlock_bh(&msk->pm.lock);
-		pr_debug("send ack for %s%s%s",
-			 mptcp_pm_should_add_signal(msk) ? "add_addr" : "rm_addr",
-			 mptcp_pm_should_add_signal_ipv6(msk) ? " [ipv6]" : "",
-			 mptcp_pm_should_add_signal_port(msk) ? " [port]" : "");
+		pr_debug("send ack for %s",
+			 mptcp_pm_should_add_signal(msk) ? "add_addr" : "rm_addr");
 
 		slow = lock_sock_fast(ssk);
 		tcp_send_ack(ssk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 25056c3..eaa19b9 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -176,8 +176,6 @@ enum mptcp_pm_status {
 enum mptcp_addr_signal_status {
 	MPTCP_ADD_ADDR_SIGNAL,
 	MPTCP_ADD_ADDR_ECHO,
-	MPTCP_ADD_ADDR_IPV6,
-	MPTCP_ADD_ADDR_PORT,
 	MPTCP_RM_ADDR_SIGNAL,
 };
 
@@ -723,16 +721,6 @@ static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
 }
 
-static inline bool mptcp_pm_should_add_signal_ipv6(struct mptcp_sock *msk)
-{
-	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_IPV6);
-}
-
-static inline bool mptcp_pm_should_add_signal_port(struct mptcp_sock *msk)
-{
-	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_PORT);
-}
-
 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
 {
 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
-- 
1.8.3.1

Re: [PATCH v2 1/4] mptcp: fix ADD_ADDR and RM_ADDR maybe flush addr_signal each other

[Mat Martineau]

On Tue, 15 Jun 2021, Yonglong Li wrote:

> ADD_ADDR share pm.addr_signal with RM_ADDR, so after RM_ADDR/ADD_ADDR
> done we should not clean ADD_ADDR/RM_ADDR's addr_signal.
>
> Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
> ---
> net/mptcp/pm.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index 9d00fa6..74886a3 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -252,6 +252,7 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup)
> bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> 			      struct mptcp_addr_info *saddr, bool *echo, bool *port)
> {
> +	u8 add_addr;
> 	int ret = false;
>
> 	spin_lock_bh(&msk->pm.lock);
> @@ -267,7 +268,8 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> 		goto out_unlock;
>
> 	*saddr = msk->pm.local;
> -	WRITE_ONCE(msk->pm.addr_signal, 0);
> +	add_addr = msk->pm.addr_signal & BIT(MPTCP_RM_ADDR_SIGNAL);

Hello Yonglong, thank you for your revised patch series.

It would be better to use ~BIT(MPTCP_ADD_ADDR_SIGNAL), similar to the 
change in mptcp_pm_rm_addr_signal() below.

> +	WRITE_ONCE(msk->pm.addr_signal, add_addr);
> 	ret = true;
>
> out_unlock:
> @@ -278,6 +280,7 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> 			     struct mptcp_rm_list *rm_list)
> {
> +	u8 rm_addr;
> 	int ret = false, len;
>
> 	spin_lock_bh(&msk->pm.lock);
> @@ -286,16 +289,17 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> 	if (!mptcp_pm_should_rm_signal(msk))
> 		goto out_unlock;
>
> +	rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL);
> 	len = mptcp_rm_addr_len(&msk->pm.rm_list_tx);
> 	if (len < 0) {
> -		WRITE_ONCE(msk->pm.addr_signal, 0);
> +		WRITE_ONCE(msk->pm.addr_signal, rm_addr);
> 		goto out_unlock;
> 	}
> 	if (remaining < len)
> 		goto out_unlock;
>
> 	*rm_list = msk->pm.rm_list_tx;
> -	WRITE_ONCE(msk->pm.addr_signal, 0);
> +	WRITE_ONCE(msk->pm.addr_signal, rm_addr);
> 	ret = true;
>
> out_unlock:
> -- 
> 1.8.3.1
>
>

--
Mat Martineau
Intel

Re: [PATCH v2 2/4] mptcp: make MPTCP_ADD_ADDR_SIGNAL and MPTCP_ADD_ADDR_ECHO separate

[Mat Martineau]

On Tue, 15 Jun 2021, Yonglong Li wrote:

> MPTCP_ADD_ADDR_SIGNAL only for action of sending ADD_ADDR
> MPTCP_ADD_ADDR_ECHO only for action of sending echo ADD_ADDR
> add a mptcp_addr_info in struct mptcp_out_options for echo ADD_ADDR
>
> to prepare for the next patch.
>
> Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
> ---
> include/net/mptcp.h    |  1 +
> net/mptcp/pm.c         | 13 ++++++++-----
> net/mptcp/pm_netlink.c |  4 ++--
> net/mptcp/protocol.h   |  6 ++++++
> 4 files changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/include/net/mptcp.h b/include/net/mptcp.h
> index d61bbbf..637e90b 100644
> --- a/include/net/mptcp.h
> +++ b/include/net/mptcp.h
> @@ -62,6 +62,7 @@ struct mptcp_out_options {
> 	u64 rcvr_key;
> 	u64 ahmac;
> 	struct mptcp_addr_info addr;
> +	struct mptcp_addr_info remote;
> 	struct mptcp_rm_list rm_list;
> 	u8 join_id;
> 	u8 backup;
> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index 74886a3..9966ed1 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -18,7 +18,7 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
> {
> 	u8 add_addr = READ_ONCE(msk->pm.addr_signal);
>
> -	pr_debug("msk=%p, local_id=%d", msk, addr->id);
> +	pr_debug("msk=%p, local_id=%d, echo:%d", msk, addr->id, echo);
>
> 	lockdep_assert_held(&msk->pm.lock);
>
> @@ -27,10 +27,13 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
> 		return -EINVAL;
> 	}
>
> -	msk->pm.local = *addr;
> -	add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
> -	if (echo)
> +	if (echo) {
> +		msk->pm.remote = *addr;
> 		add_addr |= BIT(MPTCP_ADD_ADDR_ECHO);
> +	} else {
> +		msk->pm.local = *addr;
> +		add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
> +	}
> 	if (addr->family == AF_INET6)
> 		add_addr |= BIT(MPTCP_ADD_ADDR_IPV6);
> 	if (addr->port)
> @@ -214,7 +217,7 @@ void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
>
> void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk)
> {
> -	if (!mptcp_pm_should_add_signal(msk))
> +	if (!mptcp_pm_should_add_signal_echo(msk))
> 		return;
>
> 	mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK);
> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index c53e500..ae700bd 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -317,14 +317,14 @@ static void mptcp_pm_add_timer(struct timer_list *timer)
> 	if (!entry->addr.id)
> 		return;
>
> -	if (mptcp_pm_should_add_signal(msk)) {
> +	if (mptcp_pm_should_add_addr(msk)) {
> 		sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
> 		goto out;
> 	}
>
> 	spin_lock_bh(&msk->pm.lock);
>
> -	if (!mptcp_pm_should_add_signal(msk)) {
> +	if (!mptcp_pm_should_add_addr(msk)) {
> 		pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
> 		mptcp_pm_announce_addr(msk, &entry->addr, false);
> 		mptcp_pm_add_addr_send_ack(msk);
> diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
> index 6c2322e..d14d03e 100644
> --- a/net/mptcp/protocol.h
> +++ b/net/mptcp/protocol.h
> @@ -708,6 +708,12 @@ void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
>
> static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
> {
> +	return READ_ONCE(msk->pm.addr_signal) &
> +		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
> +}
> +
> +static inline bool mptcp_pm_should_add_addr(struct mptcp_sock *msk)

To fit with the naming of the other functions here, I suggest naming this 
function mptcp_pm_should_add_signal_addr() instead.

> +{
> 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
> }
>
> -- 
> 1.8.3.1
>
>

--
Mat Martineau
Intel

Re: [PATCH v2 3/4] mptcp: build ADD_ADDR/echo-ADD_ADDR option according pm.add_signal

[Mat Martineau]

On Tue, 15 Jun 2021, Yonglong Li wrote:

> according MPTCP_ADD_ADDR_SIGNAL and MPTCP_ADD_ADDR_ECHO flag build
> ADD_ADDR/echo-ADD_ADDR option
>
> add a suboptions type OPTION_MPTCP_ADD_ECHO to mark as echo option
>
> Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
> ---
> net/mptcp/options.c  | 161 +++++++++++++++++++++++++++++++++------------------
> net/mptcp/pm.c       |  32 ++++------
> net/mptcp/protocol.h |  13 +++--
> 3 files changed, 124 insertions(+), 82 deletions(-)
>
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index 1aec016..8875ba4 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -655,43 +655,72 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *
> 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
> 	bool drop_other_suboptions = false;
> 	unsigned int opt_size = *size;
> -	bool echo;
> -	bool port;
> +	struct mptcp_addr_info remote;
> +	struct mptcp_addr_info local;
> +	int ret = false;
> +	u8 add_addr;
> 	int len;
>
> -	if ((mptcp_pm_should_add_signal_ipv6(msk) ||
> -	     mptcp_pm_should_add_signal_port(msk) ||
> -	     mptcp_pm_should_add_signal_echo(msk)) &&
> -	    skb && skb_is_tcp_pure_ack(skb)) {
> -		pr_debug("drop other suboptions");
> -		opts->suboptions = 0;
> -		opts->ext_copy.use_ack = 0;
> -		opts->ext_copy.use_map = 0;
> -		remaining += opt_size;
> -		drop_other_suboptions = true;
> -	}
> -
> -	if (!mptcp_pm_should_add_signal(msk) ||
> -	    !(mptcp_pm_add_addr_signal(msk, remaining, &opts->addr, &echo, &port)))
> -		return false;
> -
> -	len = mptcp_add_addr_len(opts->addr.family, echo, port);
> -	if (remaining < len)
> -		return false;
> -
> -	*size = len;
> -	if (drop_other_suboptions)
> -		*size -= opt_size;
> -	opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
> -	if (!echo) {
> +	if (!mptcp_pm_should_add_signal(msk))
> +		goto out;
> +
> +	*size = 0;
> +	mptcp_pm_add_addr_signal(msk, &local, &remote, &add_addr);

Return value of this function is ignored, so it shouldn't return bool 
anymore. However, read below about locking and handling of the add_addr 
value before making changes.

> +	if (mptcp_pm_should_add_signal_echo(msk)) {
> +		if (skb && skb_is_tcp_pure_ack(skb)) {
> +			pr_debug("drop other suboptions");
> +			opts->suboptions = 0;
> +			opts->ext_copy.use_ack = 0;
> +			opts->ext_copy.use_map = 0;
> +			remaining += opt_size;
> +			drop_other_suboptions = true;
> +		}
> +		len = mptcp_add_addr_len(remote.family, true, !!remote.port);
> +		if (remaining < len && mptcp_pm_should_add_addr(msk))
> +			goto add_addr;
> +		else if (remaining < len)
> +			goto out;
> +		remaining -= len;
> +		*size += len;
> +		opts->remote = remote;
> +		add_addr &= ~BIT(MPTCP_ADD_ADDR_ECHO);
> +		opts->suboptions |= OPTION_MPTCP_ADD_ECHO;
> +		pr_debug("addr_id=%d, echo=1, port=%d addr_signal:%x",
> +			 opts->remote.id, ntohs(opts->remote.port), add_addr);
> +	} else if (mptcp_pm_should_add_addr(msk)) {
> +add_addr:
> +		if ((local.family == AF_INET6 || local.port) && skb &&
> +		    skb_is_tcp_pure_ack(skb)) {
> +			pr_debug("drop other suboptions");
> +			opts->suboptions = 0;
> +			opts->ext_copy.use_ack = 0;
> +			opts->ext_copy.use_map = 0;
> +			remaining += opt_size;
> +			drop_other_suboptions = true;
> +		}
> +		len = mptcp_add_addr_len(local.family, false, !!local.port);
> +		if (remaining < len)
> +			goto out;
> +		*size += len;
> +		opts->addr = local;
> 		opts->ahmac = add_addr_generate_hmac(msk->local_key,
> 						     msk->remote_key,
> 						     &opts->addr);
> +		opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
> +		add_addr &= ~BIT(MPTCP_ADD_ADDR_SIGNAL);
> +		pr_debug("addr_id=%d, ahmac=%llu, echo=0, port=%d, addr_signal:%x",
> +			 opts->addr.id, opts->ahmac, ntohs(opts->addr.port), add_addr);
> 	}
> -	pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
> -		 opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port));
>
> -	return true;
> +	if (drop_other_suboptions)
> +		*size -= opt_size;
> +	spin_lock_bh(&msk->pm.lock);
> +	WRITE_ONCE(msk->pm.addr_signal, add_addr);
> +	spin_unlock_bh(&msk->pm.lock);

It's not safe to do a read-modify-write of msk->pm.addr_signal if the pm 
lock is not held for the *entire* time. Another thread could have set or 
cleared any other bit in msk->pm_addr_signal while the lock was not held 
here, and this code would overwrite any of those changes.

> +	ret = true;
> +
> +out:
> +	return ret;
> }
>
> static bool mptcp_established_options_rm_addr(struct sock *sk,

--
Mat Martineau
Intel

Re: [PATCH v2 1/4] mptcp: fix ADD_ADDR and RM_ADDR maybe flush addr_signal each other

[Yonglong Li]

On 2021/6/17 7:30, Mat Martineau wrote:
> On Tue, 15 Jun 2021, Yonglong Li wrote:
> 
>> ADD_ADDR share pm.addr_signal with RM_ADDR, so after RM_ADDR/ADD_ADDR
>> done we should not clean ADD_ADDR/RM_ADDR's addr_signal.
>>
>> Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
>> ---
>> net/mptcp/pm.c | 10 +++++++---
>> 1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
>> index 9d00fa6..74886a3 100644
>> --- a/net/mptcp/pm.c
>> +++ b/net/mptcp/pm.c
>> @@ -252,6 +252,7 @@ void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup)
>> bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
>>                   struct mptcp_addr_info *saddr, bool *echo, bool *port)
>> {
>> +    u8 add_addr;
>>     int ret = false;
>>
>>     spin_lock_bh(&msk->pm.lock);
>> @@ -267,7 +268,8 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
>>         goto out_unlock;
>>
>>     *saddr = msk->pm.local;
>> -    WRITE_ONCE(msk->pm.addr_signal, 0);
>> +    add_addr = msk->pm.addr_signal & BIT(MPTCP_RM_ADDR_SIGNAL);
> 
> Hello Yonglong, thank you for your revised patch series.
> 
> It would be better to use ~BIT(MPTCP_ADD_ADDR_SIGNAL), similar to the change in 
Hi Mat, Thanks for your review.
If use ~BIT(MPTCP_ADD_ADDR_SIGNAL), MPTCP_ADD_ADDR_ECHO maybe not being clean out. MPTCP_ADD_ADDR_ECHO
and MPTCP_ADD_ADDR_SIGNAL are being set with pm.lock at the same time, So I think here use
BIT(MPTCP_RM_ADDR_SIGNAL) is ok.

mptcp_pm_rm_addr_signal() below.
> 
>> +    WRITE_ONCE(msk->pm.addr_signal, add_addr);
>>     ret = true;
>>
>> out_unlock:
>> @@ -278,6 +280,7 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
>> bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
>>                  struct mptcp_rm_list *rm_list)
>> {
>> +    u8 rm_addr;
>>     int ret = false, len;
>>
>>     spin_lock_bh(&msk->pm.lock);
>> @@ -286,16 +289,17 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
>>     if (!mptcp_pm_should_rm_signal(msk))
>>         goto out_unlock;
>>
>> +    rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL);
>>     len = mptcp_rm_addr_len(&msk->pm.rm_list_tx);
>>     if (len < 0) {
>> -        WRITE_ONCE(msk->pm.addr_signal, 0);
>> +        WRITE_ONCE(msk->pm.addr_signal, rm_addr);
>>         goto out_unlock;
>>     }
>>     if (remaining < len)
>>         goto out_unlock;
>>
>>     *rm_list = msk->pm.rm_list_tx;
>> -    WRITE_ONCE(msk->pm.addr_signal, 0);
>> +    WRITE_ONCE(msk->pm.addr_signal, rm_addr);
>>     ret = true;
>>
>> out_unlock:
>> -- 
>> 1.8.3.1
>>
>>
> 
> -- 
> Mat Martineau
> Intel
> 
> 

Re: [PATCH v2 3/4] mptcp: build ADD_ADDR/echo-ADD_ADDR option according pm.add_signal

[Yonglong Li]

On 2021/6/17 7:47, Mat Martineau wrote:
> On Tue, 15 Jun 2021, Yonglong Li wrote:
> 
>> according MPTCP_ADD_ADDR_SIGNAL and MPTCP_ADD_ADDR_ECHO flag build
>> ADD_ADDR/echo-ADD_ADDR option
>>
>> add a suboptions type OPTION_MPTCP_ADD_ECHO to mark as echo option
>>
>> Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
>> ---
>> net/mptcp/options.c  | 161 +++++++++++++++++++++++++++++++++------------------
>> net/mptcp/pm.c       |  32 ++++------
>> net/mptcp/protocol.h |  13 +++--
>> 3 files changed, 124 insertions(+), 82 deletions(-)
>>
>> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
>> index 1aec016..8875ba4 100644
>> --- a/net/mptcp/options.c
>> +++ b/net/mptcp/options.c
>> @@ -655,43 +655,72 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *
>>     struct mptcp_sock *msk = mptcp_sk(subflow->conn);
>>     bool drop_other_suboptions = false;
>>     unsigned int opt_size = *size;
>> -    bool echo;
>> -    bool port;
>> +    struct mptcp_addr_info remote;
>> +    struct mptcp_addr_info local;
>> +    int ret = false;
>> +    u8 add_addr;
>>     int len;
>>
>> -    if ((mptcp_pm_should_add_signal_ipv6(msk) ||
>> -         mptcp_pm_should_add_signal_port(msk) ||
>> -         mptcp_pm_should_add_signal_echo(msk)) &&
>> -        skb && skb_is_tcp_pure_ack(skb)) {
>> -        pr_debug("drop other suboptions");
>> -        opts->suboptions = 0;
>> -        opts->ext_copy.use_ack = 0;
>> -        opts->ext_copy.use_map = 0;
>> -        remaining += opt_size;
>> -        drop_other_suboptions = true;
>> -    }
>> -
>> -    if (!mptcp_pm_should_add_signal(msk) ||
>> -        !(mptcp_pm_add_addr_signal(msk, remaining, &opts->addr, &echo, &port)))
>> -        return false;
>> -
>> -    len = mptcp_add_addr_len(opts->addr.family, echo, port);
>> -    if (remaining < len)
>> -        return false;
>> -
>> -    *size = len;
>> -    if (drop_other_suboptions)
>> -        *size -= opt_size;
>> -    opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
>> -    if (!echo) {
>> +    if (!mptcp_pm_should_add_signal(msk))
>> +        goto out;
>> +
>> +    *size = 0;
>> +    mptcp_pm_add_addr_signal(msk, &local, &remote, &add_addr);
> 
> Return value of this function is ignored, so it shouldn't return bool anymore. However, read below about locking and handling of the add_addr value before making changes.
> 
>> +    if (mptcp_pm_should_add_signal_echo(msk)) {
>> +        if (skb && skb_is_tcp_pure_ack(skb)) {
>> +            pr_debug("drop other suboptions");
>> +            opts->suboptions = 0;
>> +            opts->ext_copy.use_ack = 0;
>> +            opts->ext_copy.use_map = 0;
>> +            remaining += opt_size;
>> +            drop_other_suboptions = true;
>> +        }
>> +        len = mptcp_add_addr_len(remote.family, true, !!remote.port);
>> +        if (remaining < len && mptcp_pm_should_add_addr(msk))
>> +            goto add_addr;
>> +        else if (remaining < len)
>> +            goto out;
>> +        remaining -= len;
>> +        *size += len;
>> +        opts->remote = remote;
>> +        add_addr &= ~BIT(MPTCP_ADD_ADDR_ECHO);
>> +        opts->suboptions |= OPTION_MPTCP_ADD_ECHO;
>> +        pr_debug("addr_id=%d, echo=1, port=%d addr_signal:%x",
>> +             opts->remote.id, ntohs(opts->remote.port), add_addr);
>> +    } else if (mptcp_pm_should_add_addr(msk)) {
>> +add_addr:
>> +        if ((local.family == AF_INET6 || local.port) && skb &&
>> +            skb_is_tcp_pure_ack(skb)) {
>> +            pr_debug("drop other suboptions");
>> +            opts->suboptions = 0;
>> +            opts->ext_copy.use_ack = 0;
>> +            opts->ext_copy.use_map = 0;
>> +            remaining += opt_size;
>> +            drop_other_suboptions = true;
>> +        }
>> +        len = mptcp_add_addr_len(local.family, false, !!local.port);
>> +        if (remaining < len)
>> +            goto out;
>> +        *size += len;
>> +        opts->addr = local;
>>         opts->ahmac = add_addr_generate_hmac(msk->local_key,
>>                              msk->remote_key,
>>                              &opts->addr);
>> +        opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
>> +        add_addr &= ~BIT(MPTCP_ADD_ADDR_SIGNAL);
>> +        pr_debug("addr_id=%d, ahmac=%llu, echo=0, port=%d, addr_signal:%x",
>> +             opts->addr.id, opts->ahmac, ntohs(opts->addr.port), add_addr);
>>     }
>> -    pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
>> -         opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port));
>>
>> -    return true;
>> +    if (drop_other_suboptions)
>> +        *size -= opt_size;
>> +    spin_lock_bh(&msk->pm.lock);
>> +    WRITE_ONCE(msk->pm.addr_signal, add_addr);
>> +    spin_unlock_bh(&msk->pm.lock);
> 
> It's not safe to do a read-modify-write of msk->pm.addr_signal if the pm lock is not held for the *entire* time. Another thread could have set or cleared any other bit in msk->pm_addr_signal while the lock was not held here, and this code would overwrite any of those changes.

right. Thanks for you review. I will prepare v2 patch.

> 
>> +    ret = true;
>> +
>> +out:
>> +    return ret;
>> }
>>
>> static bool mptcp_established_options_rm_addr(struct sock *sk,
> 
> -- 
> Mat Martineau
> Intel
> 
>