mptcp: local addresses fullmesh

In mptcp_pm_nl_add_addr_received(), fill a temporary allocate array of
all local address corresponding to the fullmesh endpoint. If such array
is empty, keep the current behavior.

Elsewhere loop on such array and create a subflow for each local address
towards the given remote address

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliangtang@xiaomi.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index bf5b9b4..6e3df62 100644 (file)
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -534,13 +534,67 @@ static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
        mptcp_pm_create_subflow_or_signal_addr(msk);
 }
 
+/* Fill all the local addresses into the array addrs[],
+ * and return the array size.
+ */
+static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
+                                            struct mptcp_addr_info *addrs)
+{
+       struct sock *sk = (struct sock *)msk;
+       struct mptcp_pm_addr_entry *entry;
+       struct mptcp_addr_info local;
+       struct pm_nl_pernet *pernet;
+       unsigned int subflows_max;
+       int i = 0;
+
+       pernet = net_generic(sock_net(sk), pm_nl_pernet_id);
+       subflows_max = mptcp_pm_get_subflows_max(msk);
+
+       rcu_read_lock();
+       __mptcp_flush_join_list(msk);
+       list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+               if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
+                       continue;
+
+               if (entry->addr.family != sk->sk_family) {
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+                       if ((entry->addr.family == AF_INET &&
+                            !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
+                           (sk->sk_family == AF_INET &&
+                            !ipv6_addr_v4mapped(&entry->addr.addr6)))
+#endif
+                               continue;
+               }
+
+               if (msk->pm.subflows < subflows_max) {
+                       msk->pm.subflows++;
+                       addrs[i++] = entry->addr;
+               }
+       }
+       rcu_read_unlock();
+
+       /* If the array is empty, fill in the single
+        * 'IPADDRANY' local address
+        */
+       if (!i) {
+               memset(&local, 0, sizeof(local));
+               local.family = msk->pm.remote.family;
+
+               msk->pm.subflows++;
+               addrs[i++] = local;
+       }
+
+       return i;
+}
+
 static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 {
+       struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
        struct sock *sk = (struct sock *)msk;
        unsigned int add_addr_accept_max;
        struct mptcp_addr_info remote;
-       struct mptcp_addr_info local;
        unsigned int subflows_max;
+       int i, nr;
 
        add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
        subflows_max = mptcp_pm_get_subflows_max(msk);
@@ -552,23 +606,22 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
        if (lookup_subflow_by_daddr(&msk->conn_list, &msk->pm.remote))
                goto add_addr_echo;
 
-       msk->pm.add_addr_accepted++;
-       msk->pm.subflows++;
-       if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
-           msk->pm.subflows >= subflows_max)
-               WRITE_ONCE(msk->pm.accept_addr, false);
-
        /* 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;
-       memset(&local, 0, sizeof(local));
-       local.family = remote.family;
+       nr = fill_local_addresses_vec(msk, addrs);
+
+       msk->pm.add_addr_accepted++;
+       if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
+           msk->pm.subflows >= subflows_max)
+               WRITE_ONCE(msk->pm.accept_addr, false);
 
        spin_unlock_bh(&msk->pm.lock);
-       __mptcp_subflow_connect(sk, &local, &remote);
+       for (i = 0; i < nr; i++)
+               __mptcp_subflow_connect(sk, &addrs[i], &remote);
        spin_lock_bh(&msk->pm.lock);
 
 add_addr_echo: