Merge branch 'mptcp-next'

Mat Martineau says:

====================
mptcp: Cleanup, a new test case, and header trimming

Some more patches to include from the MPTCP tree:

Patches 1-6 refactor an address-related data structure and reduce some
duplicate code that handles IPv4 and IPv6 addresses.

Patch 7 adds a test case for the MPTCP netlink interface, passing a
specific ifindex to the kernel.

Patch 8 drops extra header options from IPv4 address echo packets,
improving consistency and testability between IPv4 and IPv6.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 115 insertions, 175 deletions

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 16fe34d139c3..83f23774b908 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -41,20 +41,25 @@ struct mptcp_rm_list {
 	u8 nr;
 };
 
+struct mptcp_addr_info {
+	u8			id;
+	sa_family_t		family;
+	__be16			port;
+	union {
+		struct in_addr	addr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+		struct in6_addr	addr6;
+#endif
+	};
+};
+
 struct mptcp_out_options {
 #if IS_ENABLED(CONFIG_MPTCP)
 	u16 suboptions;
 	u64 sndr_key;
 	u64 rcvr_key;
-	union {
-		struct in_addr addr;
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-		struct in6_addr addr6;
-#endif
-	};
-	u8 addr_id;
-	u16 port;
 	u64 ahmac;
+	struct mptcp_addr_info addr;
 	struct mptcp_rm_list rm_list;
 	u8 join_id;
 	u8 backup;
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 4b7119eb2c31..d51c3ad54d9a 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -220,45 +220,45 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 		if (!mp_opt->echo) {
 			if (opsize == TCPOLEN_MPTCP_ADD_ADDR ||
 			    opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT)
-				mp_opt->family = MPTCP_ADDR_IPVERSION_4;
+				mp_opt->addr.family = AF_INET;
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 			else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 ||
 				 opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT)
-				mp_opt->family = MPTCP_ADDR_IPVERSION_6;
+				mp_opt->addr.family = AF_INET6;
 #endif
 			else
 				break;
 		} else {
 			if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE ||
 			    opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT)
-				mp_opt->family = MPTCP_ADDR_IPVERSION_4;
+				mp_opt->addr.family = AF_INET;
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 			else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE ||
 				 opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT)
-				mp_opt->family = MPTCP_ADDR_IPVERSION_6;
+				mp_opt->addr.family = AF_INET6;
 #endif
 			else
 				break;
 		}
 
 		mp_opt->add_addr = 1;
-		mp_opt->addr_id = *ptr++;
-		if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) {
-			memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4);
+		mp_opt->addr.id = *ptr++;
+		if (mp_opt->addr.family == AF_INET) {
+			memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4);
 			ptr += 4;
 			if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT ||
 			    opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) {
-				mp_opt->port = get_unaligned_be16(ptr);
+				mp_opt->addr.port = htons(get_unaligned_be16(ptr));
 				ptr += 2;
 			}
 		}
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 		else {
-			memcpy(mp_opt->addr6.s6_addr, (u8 *)ptr, 16);
+			memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16);
 			ptr += 16;
 			if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT ||
 			    opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) {
-				mp_opt->port = get_unaligned_be16(ptr);
+				mp_opt->addr.port = htons(get_unaligned_be16(ptr));
 				ptr += 2;
 			}
 		}
@@ -268,8 +268,8 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 			ptr += 8;
 		}
 		pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d",
-			 (mp_opt->family == MPTCP_ADDR_IPVERSION_6) ? "6" : "",
-			 mp_opt->addr_id, mp_opt->ahmac, mp_opt->echo, mp_opt->port);
+			 (mp_opt->addr.family == AF_INET6) ? "6" : "",
+			 mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port));
 		break;
 
 	case MPTCPOPT_RM_ADDR:
@@ -335,7 +335,7 @@ void mptcp_get_options(const struct sk_buff *skb,
 	mp_opt->add_addr = 0;
 	mp_opt->ahmac = 0;
 	mp_opt->fastclose = 0;
-	mp_opt->port = 0;
+	mp_opt->addr.port = 0;
 	mp_opt->rm_addr = 0;
 	mp_opt->dss = 0;
 	mp_opt->mp_prio = 0;
@@ -583,39 +583,32 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
 	return true;
 }
 
-static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id,
-				  struct in_addr *addr, u16 port)
-{
-	u8 hmac[SHA256_DIGEST_SIZE];
-	u8 msg[7];
-
-	msg[0] = addr_id;
-	memcpy(&msg[1], &addr->s_addr, 4);
-	msg[5] = port >> 8;
-	msg[6] = port & 0xFF;
-
-	mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac);
-
-	return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
-}
-
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id,
-				   struct in6_addr *addr, u16 port)
+static u64 add_addr_generate_hmac(u64 key1, u64 key2,
+				  struct mptcp_addr_info *addr)
 {
+	u16 port = ntohs(addr->port);
 	u8 hmac[SHA256_DIGEST_SIZE];
 	u8 msg[19];
+	int i = 0;
 
-	msg[0] = addr_id;
-	memcpy(&msg[1], &addr->s6_addr, 16);
-	msg[17] = port >> 8;
-	msg[18] = port & 0xFF;
+	msg[i++] = addr->id;
+	if (addr->family == AF_INET) {
+		memcpy(&msg[i], &addr->addr.s_addr, 4);
+		i += 4;
+	}
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	else if (addr->family == AF_INET6) {
+		memcpy(&msg[i], &addr->addr6.s6_addr, 16);
+		i += 16;
+	}
+#endif
+	msg[i++] = port >> 8;
+	msg[i++] = port & 0xFF;
 
-	mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac);
+	mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac);
 
 	return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
 }
-#endif
 
 static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb,
 					       unsigned int *size,
@@ -626,13 +619,13 @@ 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;
-	struct mptcp_addr_info saddr;
 	bool echo;
 	bool port;
 	int len;
 
 	if ((mptcp_pm_should_add_signal_ipv6(msk) ||
-	     mptcp_pm_should_add_signal_port(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;
@@ -643,45 +636,24 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *
 	}
 
 	if (!mptcp_pm_should_add_signal(msk) ||
-	    !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo, &port)))
+	    !(mptcp_pm_add_addr_signal(msk, remaining, &opts->addr, &echo, &port)))
 		return false;
 
-	len = mptcp_add_addr_len(saddr.family, echo, port);
+	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->addr_id = saddr.id;
-	if (port)
-		opts->port = ntohs(saddr.port);
-	if (saddr.family == AF_INET) {
-		opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
-		opts->addr = saddr.addr;
-		if (!echo) {
-			opts->ahmac = add_addr_generate_hmac(msk->local_key,
-							     msk->remote_key,
-							     opts->addr_id,
-							     &opts->addr,
-							     opts->port);
-		}
+	opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
+	if (!echo) {
+		opts->ahmac = add_addr_generate_hmac(msk->local_key,
+						     msk->remote_key,
+						     &opts->addr);
 	}
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-	else if (saddr.family == AF_INET6) {
-		opts->suboptions |= OPTION_MPTCP_ADD_ADDR6;
-		opts->addr6 = saddr.addr6;
-		if (!echo) {
-			opts->ahmac = add_addr6_generate_hmac(msk->local_key,
-							      msk->remote_key,
-							      opts->addr_id,
-							      &opts->addr6,
-							      opts->port);
-		}
-	}
-#endif
 	pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
-		 opts->addr_id, opts->ahmac, echo, opts->port);
+		 opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port));
 
 	return true;
 }
@@ -998,18 +970,9 @@ static bool add_addr_hmac_valid(struct mptcp_sock *msk,
 	if (mp_opt->echo)
 		return true;
 
-	if (mp_opt->family == MPTCP_ADDR_IPVERSION_4)
-		hmac = add_addr_generate_hmac(msk->remote_key,
-					      msk->local_key,
-					      mp_opt->addr_id, &mp_opt->addr,
-					      mp_opt->port);
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-	else
-		hmac = add_addr6_generate_hmac(msk->remote_key,
-					       msk->local_key,
-					       mp_opt->addr_id, &mp_opt->addr6,
-					       mp_opt->port);
-#endif
+	hmac = add_addr_generate_hmac(msk->remote_key,
+				      msk->local_key,
+				      &mp_opt->addr);
 
 	pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
 		 msk, (unsigned long long)hmac,
@@ -1050,30 +1013,16 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 	}
 
 	if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) {
-		struct mptcp_addr_info addr;
-
-		addr.port = htons(mp_opt.port);
-		addr.id = mp_opt.addr_id;
-		if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) {
-			addr.family = AF_INET;
-			addr.addr = mp_opt.addr;
-		}
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-		else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) {
-			addr.family = AF_INET6;
-			addr.addr6 = mp_opt.addr6;
-		}
-#endif
 		if (!mp_opt.echo) {
-			mptcp_pm_add_addr_received(msk, &addr);
+			mptcp_pm_add_addr_received(msk, &mp_opt.addr);
 			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
 		} else {
-			mptcp_pm_add_addr_echoed(msk, &addr);
-			mptcp_pm_del_add_timer(msk, &addr);
+			mptcp_pm_add_addr_echoed(msk, &mp_opt.addr);
+			mptcp_pm_del_add_timer(msk, &mp_opt.addr);
 			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
 		}
 
-		if (mp_opt.port)
+		if (mp_opt.addr.port)
 			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD);
 
 		mp_opt.add_addr = 0;
@@ -1204,20 +1153,16 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 	}
 
 mp_capable_done:
-	if ((OPTION_MPTCP_ADD_ADDR
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-	     | OPTION_MPTCP_ADD_ADDR6
-#endif
-	    ) & opts->suboptions) {
+	if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
 		u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
 		u8 echo = MPTCP_ADDR_ECHO;
 
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
-		if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions)
+		if (opts->addr.family == AF_INET6)
 			len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
 #endif
 
-		if (opts->port)
+		if (opts->addr.port)
 			len += TCPOLEN_MPTCP_PORT_LEN;
 
 		if (opts->ahmac) {
@@ -1226,28 +1171,30 @@ mp_capable_done:
 		}
 
 		*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
-				      len, echo, opts->addr_id);
-		if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
-			memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4);
+				      len, echo, opts->addr.id);
+		if (opts->addr.family == AF_INET) {
+			memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4);
 			ptr += 1;
 		}
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
-		else if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) {
-			memcpy((u8 *)ptr, opts->addr6.s6_addr, 16);
+		else if (opts->addr.family == AF_INET6) {
+			memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16);
 			ptr += 4;
 		}
 #endif
 
-		if (!opts->port) {
+		if (!opts->addr.port) {
 			if (opts->ahmac) {
 				put_unaligned_be64(opts->ahmac, ptr);
 				ptr += 2;
 			}
 		} else {
+			u16 port = ntohs(opts->addr.port);
+
 			if (opts->ahmac) {
 				u8 *bptr = (u8 *)ptr;
 
-				put_unaligned_be16(opts->port, bptr);
+				put_unaligned_be16(port, bptr);
 				bptr += 2;
 				put_unaligned_be64(opts->ahmac, bptr);
 				bptr += 8;
@@ -1256,7 +1203,7 @@ mp_capable_done:
 
 				ptr += 3;
 			} else {
-				put_unaligned_be32(opts->port << 16 |
+				put_unaligned_be32(port << 16 |
 						   TCPOPT_NOP << 8 |
 						   TCPOPT_NOP, ptr);
 				ptr += 1;
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 51be6c34b339..6ba040897738 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -25,6 +25,8 @@ static int pm_nl_pernet_id;
 struct mptcp_pm_addr_entry {
 	struct list_head	list;
 	struct mptcp_addr_info	addr;
+	u8			flags;
+	int			ifindex;
 	struct rcu_head		rcu;
 	struct socket		*lsk;
 };
@@ -168,7 +170,7 @@ select_local_address(const struct pm_nl_pernet *pernet,
 	rcu_read_lock();
 	__mptcp_flush_join_list(msk);
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
-		if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
 			continue;
 
 		if (entry->addr.family != sk->sk_family) {
@@ -206,7 +208,7 @@ select_signal_address(struct pm_nl_pernet *pernet, unsigned int pos)
 	 * can lead to additional addresses not being announced.
 	 */
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
-		if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
+		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
 			continue;
 		if (i++ == pos) {
 			ret = entry;
@@ -459,7 +461,8 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 			check_work_pending(msk);
 			remote_address((struct sock_common *)sk, &remote);
 			spin_unlock_bh(&msk->pm.lock);
-			__mptcp_subflow_connect(sk, &local->addr, &remote);
+			__mptcp_subflow_connect(sk, &local->addr, &remote,
+						local->flags, local->ifindex);
 			spin_lock_bh(&msk->pm.lock);
 			return;
 		}
@@ -514,7 +517,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 	local.family = remote.family;
 
 	spin_unlock_bh(&msk->pm.lock);
-	__mptcp_subflow_connect(sk, &local, &remote);
+	__mptcp_subflow_connect(sk, &local, &remote, 0, 0);
 	spin_lock_bh(&msk->pm.lock);
 
 add_addr_echo:
@@ -683,7 +686,7 @@ void mptcp_pm_nl_work(struct mptcp_sock *msk)
 
 static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 {
-	return (entry->addr.flags &
+	return (entry->flags &
 		(MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
 		MPTCP_PM_ADDR_FLAG_SIGNAL;
 }
@@ -735,11 +738,11 @@ find_next:
 	if (entry->addr.id > pernet->next_id)
 		pernet->next_id = entry->addr.id;
 
-	if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
 		addr_max = pernet->add_addr_signal_max;
 		WRITE_ONCE(pernet->add_addr_signal_max, addr_max + 1);
 	}
-	if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
 		addr_max = pernet->local_addr_max;
 		WRITE_ONCE(pernet->local_addr_max, addr_max + 1);
 	}
@@ -841,10 +844,10 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 		return -ENOMEM;
 
 	entry->addr = skc_local;
-	entry->addr.ifindex = 0;
-	entry->addr.flags = 0;
 	entry->addr.id = 0;
 	entry->addr.port = 0;
+	entry->ifindex = 0;
+	entry->flags = 0;
 	entry->lsk = NULL;
 	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 	if (ret < 0)
@@ -959,14 +962,14 @@ skip_family:
 	if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) {
 		u32 val = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]);
 
-		entry->addr.ifindex = val;
+		entry->ifindex = val;
 	}
 
 	if (tb[MPTCP_PM_ADDR_ATTR_ID])
 		entry->addr.id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
 
 	if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
-		entry->addr.flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
+		entry->flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
 
 	if (tb[MPTCP_PM_ADDR_ATTR_PORT])
 		entry->addr.port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
@@ -1218,11 +1221,11 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
 		spin_unlock_bh(&pernet->lock);
 		return -EINVAL;
 	}
-	if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
 		addr_max = pernet->add_addr_signal_max;
 		WRITE_ONCE(pernet->add_addr_signal_max, addr_max - 1);
 	}
-	if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
+	if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
 		addr_max = pernet->local_addr_max;
 		WRITE_ONCE(pernet->local_addr_max, addr_max - 1);
 	}
@@ -1338,10 +1341,10 @@ static int mptcp_nl_fill_addr(struct sk_buff *skb,
 		goto nla_put_failure;
 	if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id))
 		goto nla_put_failure;
-	if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->addr.flags))
+	if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->flags))
 		goto nla_put_failure;
-	if (entry->addr.ifindex &&
-	    nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->addr.ifindex))
+	if (entry->ifindex &&
+	    nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->ifindex))
 		goto nla_put_failure;
 
 	if (addr->family == AF_INET &&
@@ -1569,7 +1572,7 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 	if (ret < 0)
 		return ret;
 
-	if (addr.addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
 		bkup = 1;
 
 	list_for_each_entry(entry, &pernet->local_addr_list, list) {
@@ -1579,9 +1582,9 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 				return ret;
 
 			if (bkup)
-				entry->addr.flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
+				entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
 			else
-				entry->addr.flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+				entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
 		}
 	}
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 40e9b05856cd..d8de1e961ab0 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -22,11 +22,10 @@
 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
-#define OPTION_MPTCP_ADD_ADDR6	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)
+#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)
 
 /* MPTCP option subtypes */
 #define MPTCPOPT_MP_CAPABLE	0
@@ -91,8 +90,6 @@
 
 /* MPTCP ADD_ADDR flags */
 #define MPTCP_ADDR_ECHO		BIT(0)
-#define MPTCP_ADDR_IPVERSION_4	4
-#define MPTCP_ADDR_IPVERSION_6	6
 
 /* MPTCP MP_PRIO flags */
 #define MPTCP_PRIO_BKUP		BIT(0)
@@ -134,7 +131,6 @@ struct mptcp_options_received {
 		add_addr : 1,
 		rm_addr : 1,
 		mp_prio : 1,
-		family : 4,
 		echo : 1,
 		backup : 1;
 	u32	token;
@@ -149,16 +145,9 @@ struct mptcp_options_received {
 		ack64:1,
 		mpc_map:1,
 		__unused:2;
-	u8	addr_id;
+	struct mptcp_addr_info addr;
 	struct mptcp_rm_list rm_list;
-	union {
-		struct in_addr	addr;
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-		struct in6_addr	addr6;
-#endif
-	};
 	u64	ahmac;
-	u16	port;
 	u8	reset_reason:4;
 	u8	reset_transient:1;
 };
@@ -169,20 +158,6 @@ static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
 		     ((nib & 0xF) << 8) | field);
 }
 
-struct mptcp_addr_info {
-	sa_family_t		family;
-	__be16			port;
-	u8			id;
-	u8			flags;
-	int			ifindex;
-	union {
-		struct in_addr addr;
-#if IS_ENABLED(CONFIG_MPTCP_IPV6)
-		struct in6_addr addr6;
-#endif
-	};
-};
-
 enum mptcp_pm_status {
 	MPTCP_PM_ADD_ADDR_RECEIVED,
 	MPTCP_PM_ADD_ADDR_SEND_ACK,
@@ -557,7 +532,8 @@ struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk);
 
 /* called with sk socket lock held */
 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
-			    const struct mptcp_addr_info *remote);
+			    const struct mptcp_addr_info *remote,
+			    u8 flags, int ifindex);
 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
 			 struct sockaddr_storage *addr,
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 223d6be5fc3b..3c19a5265a0f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1256,7 +1256,8 @@ void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
 }
 
 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
-			    const struct mptcp_addr_info *remote)
+			    const struct mptcp_addr_info *remote,
+			    u8 flags, int ifindex)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_subflow_context *subflow;
@@ -1300,7 +1301,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	if (addr.ss_family == AF_INET6)
 		addrlen = sizeof(struct sockaddr_in6);
 #endif
-	ssk->sk_bound_dev_if = loc->ifindex;
+	ssk->sk_bound_dev_if = ifindex;
 	err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
 	if (err)
 		goto failed;
@@ -1312,7 +1313,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	subflow->local_id = local_id;
 	subflow->remote_id = remote_id;
 	subflow->request_join = 1;
-	subflow->request_bkup = !!(loc->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);
 	mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
 
 	mptcp_add_pending_subflow(msk, subflow);
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index abeb24b7f8ec..fd99485cf2a4 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -777,6 +777,14 @@ subflows_tests()
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.2.2 flags subflow
 	run_tests $ns1 $ns2 10.0.1.1
 	chk_join_nr "multiple subflows, limited by server" 2 2 1
+
+	# single subflow, dev
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 0 1
+	ip netns exec $ns2 ./pm_nl_ctl limits 0 1
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags subflow dev ns2eth3
+	run_tests $ns1 $ns2 10.0.1.1
+	chk_join_nr "single subflow, dev" 1 1 1
 }
 
 signal_address_tests()