Squash to "mptcp: infinite mapping receiving"

Please update the commit log too:

'''
This patch added the infinite mapping receiving logic.

In mptcp_incoming_options(), invoke the new helper function
mptcp_infinite_map_received() to check whether the infinite mapping
is received. If it is, set the infinite_map flag of struct mptcp_ext.

In get_mapping_status(), if the infinite mapping is received, set the
map_data_len of the subflow to 0.

In subflow_check_data_avail(), only reset the subflow when the map_data_len
of the subflow is non-zero.
'''

Signed-off-by: Geliang Tang <geliang.tang@suse.com>

net/mptcp/options.c

@@ -1081,6 +1081,14 @@ static bool add_addr_hmac_valid(struct mptcp_sock *msk,
 	return hmac == mp_opt->ahmac;
 }
 
+static bool mptcp_infinite_map_received(struct mptcp_options_received *mp_opt)
+{
+	if (mp_opt->use_map && !mp_opt->data_len)
+		return true;
+
+	return false;
+}
+
 /* Return false if a subflow has been reset, else return true */
 bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 {
@@ -1089,7 +1097,9 @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 	struct mptcp_options_received mp_opt;
 	struct mptcp_ext *mpext;
 
-	if (__mptcp_check_fallback(msk)) {
+	mptcp_get_options(sk, skb, &mp_opt);
+
+	if (__mptcp_check_fallback(msk) && !mptcp_infinite_map_received(&mp_opt)) {
 		/* Keep it simple and unconditionally trigger send data cleanup and
 		 * pending queue spooling. We will need to acquire the data lock
 		 * for more accurate checks, and once the lock is acquired, such
@@ -1103,8 +1113,6 @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 		return true;
 	}
 
-	mptcp_get_options(sk, skb, &mp_opt);
-
 	/* The subflow can be in close state only if check_fully_established()
 	 * just sent a reset. If so, tell the caller to ignore the current packet.
 	 */
@@ -1206,6 +1214,8 @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 
 		if (mpext->csum_reqd)
 			mpext->csum = mp_opt.csum;
+		if (mptcp_infinite_map_received(&mp_opt))
+			mpext->infinite_map = 1;
 	}
 
 	return true;

net/mptcp/subflow.c

@@ -938,7 +938,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
 	if (!skb)
 		return MAPPING_EMPTY;
 
-	if (mptcp_check_fallback(ssk))
+	if (mptcp_check_fallback(ssk) && !mptcp_check_infinite_map(skb))
 		return MAPPING_DUMMY;
 
 	mpext = mptcp_get_ext(skb);