@@ -1234,6 +1234,41 @@ process_incoming_link(struct context *c)

     perf_pop();

 }

+void

+extract_dco_float_peer_addr(const sa_family_t socket_family,

+                            struct openvpn_sockaddr *out_osaddr,

+                            const struct sockaddr *float_sa)

+{

+    if (float_sa->sa_family == AF_INET)

+    {

+        struct sockaddr_in *float4 = (struct sockaddr_in *)float_sa;

+        /* DCO treats IPv4-mapped IPv6 addresses as pure IPv4. However, on a

+         * dual-stack socket, we need to preserve the mapping otherwise openvpn

+         * will not be able to find the peer by its transport address.

+         */

+        if (socket_family == AF_INET6)

+        {

+            out_osaddr->addr.in6.sin6_family = AF_INET6;

+            out_osaddr->addr.in6.sin6_port = float4->sin_port;

+

+            memset(&out_osaddr->addr.in6.sin6_addr.s6_addr, 0, 10);

+            out_osaddr->addr.in6.sin6_addr.s6_addr[10] = 0xff;

+            out_osaddr->addr.in6.sin6_addr.s6_addr[11] = 0xff;

+            memcpy(&out_osaddr->addr.in6.sin6_addr.s6_addr[12],

+                   &float4->sin_addr.s_addr, sizeof(in_addr_t));

+        }

+        else

+        {

+            memcpy(&out_osaddr->addr.in4, float4, sizeof(struct sockaddr_in));

+        }

+    }

+    else

+    {

+        struct sockaddr_in6 *float6 = (struct sockaddr_in6 *)float_sa;

+        memcpy(&out_osaddr->addr.in6, float6, sizeof(struct sockaddr_in6));

+    }

+}

+

 static void

 process_incoming_dco(struct context *c)

 {

@@ -189,6 +189,21 @@ bool process_incoming_link_part1(struct context *c, struct link_socket_info *lsi

 void process_incoming_link_part2(struct context *c, struct link_socket_info *lsi, const uint8_t *orig_buf);

 /**

+ * Transfers \c float_sa data extracted from an incoming DCO

+ * PEER_FLOAT_NTF to \c out_osaddr for later processing.

+ *

+ * @param socket_family - The address family of the socket

+ * @param out_osaddr - openvpn_sockaddr struct that will be filled the new

+ *      address data

+ * @param float_sa - The sockaddr struct containing the data received from the

+ *      DCO notification

+ */

+void

+extract_dco_float_peer_addr(sa_family_t socket_family,

+                            struct openvpn_sockaddr *out_osaddr,

+                            const struct sockaddr *float_sa);

+

+/**

  * Write a packet to the external network interface.

  * @ingroup external_multiplexer

  *

@@ -3169,6 +3169,18 @@ multi_process_float(struct multi_context *m, struct multi_instance *mi)

             goto done;

         }

+        /* It doesn't make sense to let a peer float to the address it already

+         * has, so we disallow it. This can happen if a DCO netlink notification

+         * gets lost and we miss a floating step.

+         */

+        if (m1->peer_id == m2->peer_id)

+        {

+            msg(M_WARN, "disallowing peer %" PRIu32 " (%s) from floating to "

+                "its own address (%s)",

+                m1->peer_id, tls_common_name(mi->context.c2.tls_multi, false),

+                mroute_addr_print(&mi->real, &gc));

+            goto done;

+        }

         msg(D_MULTI_MEDIUM, "closing instance %s", multi_instance_string(ex_mi, false, &gc));

         multi_close_instance(m, ex_mi, false);

     }

@@ -3301,6 +3313,17 @@ multi_process_incoming_dco(struct multi_context *m)

         {

             process_incoming_del_peer(m, mi, dco);

         }

+#if 0

+        else if (dco->dco_message_type == OVPN_CMD_FLOAT_PEER)

+        {

+            ASSERT(mi->context.c2.link_socket);

+            extract_dco_float_peer_addr(mi->context.c2.link_socket->info.af,

+                                        &m->top.c2.from.dest,

+                                        (struct sockaddr *)&dco->dco_float_peer_ss);

+            multi_process_float(m, mi);

+            CLEAR(dco->dco_float_peer_ss);

+        }

+#endif /* if defined(TARGET_LINUX) || defined(TARGET_WIN32) */

         else if (dco->dco_message_type == OVPN_CMD_SWAP_KEYS)

         {

             tls_session_soft_reset(mi->context.c2.tls_multi);