1 files changed, 129 insertions, 82 deletions

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 356f596e2032..b5e8de6f7507 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -83,16 +83,6 @@ static bool addresses_equal(const struct mptcp_addr_info *a,
 	return a->port == b->port;
 }
 
-static bool address_zero(const struct mptcp_addr_info *addr)
-{
-	struct mptcp_addr_info zero;
-
-	memset(&zero, 0, sizeof(zero));
-	zero.family = addr->family;
-
-	return addresses_equal(addr, &zero, true);
-}
-
 static void local_address(const struct sock_common *skc,
 			  struct mptcp_addr_info *addr)
 {
@@ -120,7 +110,7 @@ static void remote_address(const struct sock_common *skc,
 }
 
 static bool lookup_subflow_by_saddr(const struct list_head *list,
-				    struct mptcp_addr_info *saddr)
+				    const struct mptcp_addr_info *saddr)
 {
 	struct mptcp_subflow_context *subflow;
 	struct mptcp_addr_info cur;
@@ -138,7 +128,7 @@ static bool lookup_subflow_by_saddr(const struct list_head *list,
 }
 
 static bool lookup_subflow_by_daddr(const struct list_head *list,
-				    struct mptcp_addr_info *daddr)
+				    const struct mptcp_addr_info *daddr)
 {
 	struct mptcp_subflow_context *subflow;
 	struct mptcp_addr_info cur;
@@ -157,10 +147,10 @@ static bool lookup_subflow_by_daddr(const struct list_head *list,
 
 static struct mptcp_pm_addr_entry *
 select_local_address(const struct pm_nl_pernet *pernet,
-		     struct mptcp_sock *msk)
+		     const struct mptcp_sock *msk)
 {
+	const struct sock *sk = (const struct sock *)msk;
 	struct mptcp_pm_addr_entry *entry, *ret = NULL;
-	struct sock *sk = (struct sock *)msk;
 
 	msk_owned_by_me(msk);
 
@@ -190,7 +180,7 @@ select_local_address(const struct pm_nl_pernet *pernet,
 }
 
 static struct mptcp_pm_addr_entry *
-select_signal_address(struct pm_nl_pernet *pernet, struct mptcp_sock *msk)
+select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk)
 {
 	struct mptcp_pm_addr_entry *entry, *ret = NULL;
 
@@ -214,16 +204,16 @@ select_signal_address(struct pm_nl_pernet *pernet, struct mptcp_sock *msk)
 	return ret;
 }
 
-unsigned int mptcp_pm_get_add_addr_signal_max(struct mptcp_sock *msk)
+unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
 {
-	struct pm_nl_pernet *pernet;
+	const struct pm_nl_pernet *pernet;
 
-	pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
+	pernet = net_generic(sock_net((const struct sock *)msk), pm_nl_pernet_id);
 	return READ_ONCE(pernet->add_addr_signal_max);
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_signal_max);
 
-unsigned int mptcp_pm_get_add_addr_accept_max(struct mptcp_sock *msk)
+unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet;
 
@@ -232,7 +222,7 @@ unsigned int mptcp_pm_get_add_addr_accept_max(struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
 
-unsigned int mptcp_pm_get_subflows_max(struct mptcp_sock *msk)
+unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet;
 
@@ -241,7 +231,7 @@ unsigned int mptcp_pm_get_subflows_max(struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_subflows_max);
 
-unsigned int mptcp_pm_get_local_addr_max(struct mptcp_sock *msk)
+unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
 {
 	struct pm_nl_pernet *pernet;
 
@@ -264,8 +254,8 @@ bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
 }
 
 struct mptcp_pm_add_entry *
-mptcp_lookup_anno_list_by_saddr(struct mptcp_sock *msk,
-				struct mptcp_addr_info *addr)
+mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
+				const struct mptcp_addr_info *addr)
 {
 	struct mptcp_pm_add_entry *entry;
 
@@ -346,7 +336,7 @@ out:
 
 struct mptcp_pm_add_entry *
 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
-		       struct mptcp_addr_info *addr, bool check_id)
+		       const struct mptcp_addr_info *addr, bool check_id)
 {
 	struct mptcp_pm_add_entry *entry;
 	struct sock *sk = (struct sock *)msk;
@@ -364,7 +354,7 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 }
 
 static bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
-				     struct mptcp_pm_addr_entry *entry)
+				     const struct mptcp_pm_addr_entry *entry)
 {
 	struct mptcp_pm_add_entry *add_entry = NULL;
 	struct sock *sk = (struct sock *)msk;
@@ -410,8 +400,8 @@ void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
 	}
 }
 
-static bool lookup_address_in_vec(struct mptcp_addr_info *addrs, unsigned int nr,
-				  struct mptcp_addr_info *addr)
+static bool lookup_address_in_vec(const struct mptcp_addr_info *addrs, unsigned int nr,
+				  const struct mptcp_addr_info *addr)
 {
 	int i;
 
@@ -493,9 +483,9 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info,
 }
 
 static int
-lookup_id_by_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *addr)
+lookup_id_by_addr(const struct pm_nl_pernet *pernet, const struct mptcp_addr_info *addr)
 {
-	struct mptcp_pm_addr_entry *entry;
+	const struct mptcp_pm_addr_entry *entry;
 	int ret = -1;
 
 	rcu_read_lock();
@@ -546,6 +536,16 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
 		local = select_signal_address(pernet, msk);
 
+		/* due to racing events on both ends we can reach here while
+		 * previous add address is still running: if we invoke now
+		 * mptcp_pm_announce_addr(), that will fail and the
+		 * corresponding id will be marked as used.
+		 * Instead let the PM machinery reschedule us when the
+		 * current address announce will be completed.
+		 */
+		if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
+			return;
+
 		if (local) {
 			if (mptcp_pm_alloc_anno_list(msk, local)) {
 				__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
@@ -659,15 +659,20 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 		 msk->pm.add_addr_accepted, add_addr_accept_max,
 		 msk->pm.remote.family);
 
-	if (lookup_subflow_by_daddr(&msk->conn_list, &msk->pm.remote))
-		goto add_addr_echo;
+	remote = msk->pm.remote;
+	mptcp_pm_announce_addr(msk, &remote, true);
+	mptcp_pm_nl_addr_send_ack(msk);
+
+	if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
+		return;
+
+	/* pick id 0 port, if none is provided the remote address */
+	if (!remote.port)
+		remote.port = sk->sk_dport;
 
 	/* connect to the specified remote address, using whatever
 	 * local address the routing configuration will pick.
 	 */
-	remote = msk->pm.remote;
-	if (!remote.port)
-		remote.port = sk->sk_dport;
 	nr = fill_local_addresses_vec(msk, addrs);
 
 	msk->pm.add_addr_accepted++;
@@ -679,10 +684,6 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 	for (i = 0; i < nr; i++)
 		__mptcp_subflow_connect(sk, &addrs[i], &remote);
 	spin_lock_bh(&msk->pm.lock);
-
-add_addr_echo:
-	mptcp_pm_announce_addr(msk, &msk->pm.remote, true);
-	mptcp_pm_nl_addr_send_ack(msk);
 }
 
 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)
@@ -858,10 +859,18 @@ static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 		MPTCP_PM_ADDR_FLAG_SIGNAL;
 }
 
+/* caller must ensure the RCU grace period is already elapsed */
+static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)
+{
+	if (entry->lsk)
+		sock_release(entry->lsk);
+	kfree(entry);
+}
+
 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 					     struct mptcp_pm_addr_entry *entry)
 {
-	struct mptcp_pm_addr_entry *cur;
+	struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
 	unsigned int addr_max;
 	int ret = -EINVAL;
 
@@ -882,8 +891,22 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 	list_for_each_entry(cur, &pernet->local_addr_list, list) {
 		if (addresses_equal(&cur->addr, &entry->addr,
 				    address_use_port(entry) &&
-				    address_use_port(cur)))
-			goto out;
+				    address_use_port(cur))) {
+			/* allow replacing the exiting endpoint only if such
+			 * endpoint is an implicit one and the user-space
+			 * did not provide an endpoint id
+			 */
+			if (!(cur->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT))
+				goto out;
+			if (entry->addr.id)
+				goto out;
+
+			pernet->addrs--;
+			entry->addr.id = cur->addr.id;
+			list_del_rcu(&cur->list);
+			del_entry = cur;
+			break;
+		}
 	}
 
 	if (!entry->addr.id) {
@@ -919,6 +942,12 @@ find_next:
 
 out:
 	spin_unlock_bh(&pernet->lock);
+
+	/* just replaced an existing entry, free it */
+	if (del_entry) {
+		synchronize_rcu();
+		__mptcp_pm_release_addr_entry(del_entry);
+	}
 	return ret;
 }
 
@@ -992,9 +1021,6 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	if (addresses_equal(&msk_local, &skc_local, false))
 		return 0;
 
-	if (address_zero(&skc_local))
-		return 0;
-
 	pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 
 	rcu_read_lock();
@@ -1017,7 +1043,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	entry->addr.id = 0;
 	entry->addr.port = 0;
 	entry->ifindex = 0;
-	entry->flags = 0;
+	entry->flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
 	entry->lsk = NULL;
 	ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 	if (ret < 0)
@@ -1178,14 +1204,8 @@ skip_family:
 	if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
 		entry->flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
 
-	if (tb[MPTCP_PM_ADDR_ATTR_PORT]) {
-		if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
-			NL_SET_ERR_MSG_ATTR(info->extack, attr,
-					    "flags must have signal when using port");
-			return -EINVAL;
-		}
+	if (tb[MPTCP_PM_ADDR_ATTR_PORT])
 		entry->addr.port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
-	}
 
 	return 0;
 }
@@ -1231,6 +1251,22 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 	if (ret < 0)
 		return ret;
 
+	if (addr.addr.port && !(addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+		GENL_SET_ERR_MSG(info, "flags must have signal when using port");
+		return -EINVAL;
+	}
+
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL &&
+	    addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) {
+		GENL_SET_ERR_MSG(info, "flags mustn't have both signal and fullmesh");
+		return -EINVAL;
+	}
+
+	if (addr.flags & MPTCP_PM_ADDR_FLAG_IMPLICIT) {
+		GENL_SET_ERR_MSG(info, "can't create IMPLICIT endpoint");
+		return -EINVAL;
+	}
+
 	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry) {
 		GENL_SET_ERR_MSG(info, "can't allocate addr");
@@ -1282,7 +1318,7 @@ int mptcp_pm_get_flags_and_ifindex_by_id(struct net *net, unsigned int id,
 }
 
 static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
-				      struct mptcp_addr_info *addr)
+				      const struct mptcp_addr_info *addr)
 {
 	struct mptcp_pm_add_entry *entry;
 
@@ -1297,7 +1333,7 @@ static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
 }
 
 static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
-				      struct mptcp_addr_info *addr,
+				      const struct mptcp_addr_info *addr,
 				      bool force)
 {
 	struct mptcp_rm_list list = { .nr = 0 };
@@ -1315,11 +1351,12 @@ static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
 }
 
 static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
-						   struct mptcp_addr_info *addr)
+						   const struct mptcp_pm_addr_entry *entry)
 {
-	struct mptcp_sock *msk;
-	long s_slot = 0, s_num = 0;
+	const struct mptcp_addr_info *addr = &entry->addr;
 	struct mptcp_rm_list list = { .nr = 0 };
+	long s_slot = 0, s_num = 0;
+	struct mptcp_sock *msk;
 
 	pr_debug("remove_id=%d", addr->id);
 
@@ -1336,7 +1373,8 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
 
 		lock_sock(sk);
 		remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);
-		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow);
+		mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&
+					  !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));
 		if (remove_subflow)
 			mptcp_pm_remove_subflow(msk, &list);
 		release_sock(sk);
@@ -1349,14 +1387,6 @@ next:
 	return 0;
 }
 
-/* caller must ensure the RCU grace period is already elapsed */
-static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)
-{
-	if (entry->lsk)
-		sock_release(entry->lsk);
-	kfree(entry);
-}
-
 static int mptcp_nl_remove_id_zero_address(struct net *net,
 					   struct mptcp_addr_info *addr)
 {
@@ -1433,7 +1463,7 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
 	__clear_bit(entry->addr.id, pernet->id_bitmap);
 	spin_unlock_bh(&pernet->lock);
 
-	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr);
+	mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), entry);
 	synchronize_rcu();
 	__mptcp_pm_release_addr_entry(entry);
 
@@ -1448,14 +1478,12 @@ static void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
 
 	list_for_each_entry(entry, rm_list, list) {
 		if (lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) &&
-		    alist.nr < MPTCP_RM_IDS_MAX &&
-		    slist.nr < MPTCP_RM_IDS_MAX) {
-			alist.ids[alist.nr++] = entry->addr.id;
+		    slist.nr < MPTCP_RM_IDS_MAX)
 			slist.ids[slist.nr++] = entry->addr.id;
-		} else if (remove_anno_list_by_saddr(msk, &entry->addr) &&
-			 alist.nr < MPTCP_RM_IDS_MAX) {
+
+		if (remove_anno_list_by_saddr(msk, &entry->addr) &&
+		    alist.nr < MPTCP_RM_IDS_MAX)
 			alist.ids[alist.nr++] = entry->addr.id;
-		}
 	}
 
 	if (alist.nr) {
@@ -1732,9 +1760,20 @@ fail:
 	return -EMSGSIZE;
 }
 
-static int mptcp_nl_addr_backup(struct net *net,
-				struct mptcp_addr_info *addr,
-				u8 bkup)
+static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
+				 struct mptcp_addr_info *addr)
+{
+	struct mptcp_rm_list list = { .nr = 0 };
+
+	list.ids[list.nr++] = addr->id;
+
+	mptcp_pm_nl_rm_subflow_received(msk, &list);
+	mptcp_pm_create_subflow_or_signal_addr(msk);
+}
+
+static int mptcp_nl_set_flags(struct net *net,
+			      struct mptcp_addr_info *addr,
+			      u8 bkup, u8 changed)
 {
 	long s_slot = 0, s_num = 0;
 	struct mptcp_sock *msk;
@@ -1748,7 +1787,10 @@ static int mptcp_nl_addr_backup(struct net *net,
 
 		lock_sock(sk);
 		spin_lock_bh(&msk->pm.lock);
-		ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, bkup);
+		if (changed & MPTCP_PM_ADDR_FLAG_BACKUP)
+			ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, bkup);
+		if (changed & MPTCP_PM_ADDR_FLAG_FULLMESH)
+			mptcp_pm_nl_fullmesh(msk, addr);
 		spin_unlock_bh(&msk->pm.lock);
 		release_sock(sk);
 
@@ -1765,6 +1807,8 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 	struct mptcp_pm_addr_entry addr = { .addr = { .family = AF_UNSPEC }, }, *entry;
 	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
+			   MPTCP_PM_ADDR_FLAG_FULLMESH;
 	struct net *net = sock_net(skb->sk);
 	u8 bkup = 0, lookup_by_id = 0;
 	int ret;
@@ -1787,15 +1831,18 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 		spin_unlock_bh(&pernet->lock);
 		return -EINVAL;
 	}
+	if ((addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
+	    (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
+	}
 
-	if (bkup)
-		entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
-	else
-		entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+	changed = (addr.flags ^ entry->flags) & mask;
+	entry->flags = (entry->flags & ~mask) | (addr.flags & mask);
 	addr = *entry;
 	spin_unlock_bh(&pernet->lock);
 
-	mptcp_nl_addr_backup(net, &addr.addr, bkup);
+	mptcp_nl_set_flags(net, &addr.addr, bkup, changed);
 	return 0;
 }