[Openvpn-devel,L] Change in openvpn[master]: Bind to multiple ipv4/ipv6 addresses

Message ID 2080b9e7d6e7f700844b3735ff6424243c019849-HTML@gerrit.openvpn.net
State New
Headers show
Series [Openvpn-devel,L] Change in openvpn[master]: Bind to multiple ipv4/ipv6 addresses | expand

Commit Message

cron2 (Code Review) Sept. 23, 2024, 1:41 p.m. UTC
Attention is currently required from: flichtenheld, plaisthos.

Hello plaisthos, flichtenheld,

I'd like you to do a code review.
Please visit

    http://gerrit.openvpn.net/c/openvpn/+/764?usp=email

to review the following change.


Change subject: Bind to multiple ipv4/ipv6 addresses
......................................................................

Bind to multiple ipv4/ipv6 addresses

Enables the binding of multiple listen
sockets based on the specified "--local"
directives.

The main server loop has been updated
to handle both TCP and UDP connections.

The hash function has also been modified
to include the protocol during the
creation of new client instances.

Change-Id: I31bbf87e4e568021445c7512ecefadfd4a69b363
Signed-off-by: Gianmarco De Gregori <gianmarco@mandelbit.com>
---
M src/openvpn/forward.c
M src/openvpn/forward.h
M src/openvpn/init.c
M src/openvpn/mroute.c
M src/openvpn/mroute.h
M src/openvpn/mtcp.c
M src/openvpn/mtcp.h
M src/openvpn/mudp.c
M src/openvpn/mudp.h
M src/openvpn/multi.c
M src/openvpn/multi.h
M src/openvpn/openvpn.h
M src/openvpn/options.c
M src/openvpn/options.h
14 files changed, 419 insertions(+), 278 deletions(-)



  git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/64/764/1

Patch

diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c
index 2246cf7..7559a71 100644
--- a/src/openvpn/forward.c
+++ b/src/openvpn/forward.c
@@ -1764,7 +1764,7 @@ 
             if (c->options.shaper)
             {
                 int overhead = datagram_overhead(c->c2.to_link_addr->dest.addr.sa.sa_family,
-                                                 c->options.ce.proto);
+                                                 ls->info.proto);
                 shaper_wrote_bytes(&c->c2.shaper,
                                    BLEN(&c->c2.to_link) + overhead);
             }
@@ -1805,8 +1805,8 @@ 
 
                 /* Send packet */
                 size = (int)link_socket_write(ls,
-                                         &c->c2.to_link,
-                                         to_addr);
+                                              &c->c2.to_link,
+                                              to_addr);
 
                 /* Undo effect of prepend */
                 link_socket_write_post_size_adjust(&size, size_delta, &c->c2.to_link);
@@ -2054,6 +2054,173 @@ 
  */
 
 void
+get_io_flags_dowork_udp(struct context *c, struct multi_protocol *multi_io, const unsigned int flags)
+{
+    unsigned int socket = 0;
+    unsigned int tuntap = 0;
+    static uintptr_t tun_shift = 2;
+    static uintptr_t err_shift = 4;
+
+    /*
+     * Calculate the flags based on the provided 'flags' argument.
+     */
+    if (flags & IOW_WAIT_SIGNAL)
+    {
+        wait_signal(multi_io->es, (void *)err_shift);
+    }
+
+    if (flags & IOW_TO_LINK)
+    {
+        if (flags & IOW_SHAPER)
+        {
+            /*
+             * If sending this packet would put us over our traffic shaping
+             * quota, don't send -- instead compute the delay we must wait
+             * until it will be OK to send the packet.
+             */
+            int delay = 0;
+
+            /* set traffic shaping delay in microseconds */
+            if (c->options.shaper)
+            {
+                delay = max_int(delay, shaper_delay(&c->c2.shaper));
+            }
+
+            if (delay < 1000)
+            {
+                socket |= EVENT_WRITE;
+            }
+            else
+            {
+                shaper_soonest_event(&c->c2.timeval, delay);
+            }
+        }
+        else
+        {
+            socket |= EVENT_WRITE;
+        }
+    }
+    else if (!((flags & IOW_FRAG) && TO_LINK_FRAG(c)))
+    {
+        if (flags & IOW_READ_TUN)
+        {
+            tuntap |= EVENT_READ;
+        }
+    }
+
+    /*
+     * If outgoing data (for TUN/TAP device) pending, wait for ready-to-send status
+     * from device.  Otherwise, wait for incoming data on TCP/UDP port.
+     */
+    if (flags & IOW_TO_TUN)
+    {
+        tuntap |= EVENT_WRITE;
+    }
+    else
+    {
+        if (flags & IOW_READ_LINK)
+        {
+            socket |= EVENT_READ;
+        }
+    }
+
+    /*
+     * outgoing bcast buffer waiting to be sent?
+     */
+    if (flags & IOW_MBUF)
+    {
+        socket |= EVENT_WRITE;
+    }
+
+    /*
+     * Force wait on TUN input, even if also waiting on TCP/UDP output
+     */
+    if (flags & IOW_READ_TUN_FORCE)
+    {
+        tuntap |= EVENT_READ;
+    }
+
+#ifdef _WIN32
+    if (tuntap_is_wintun(c->c1.tuntap))
+    {
+        /*
+         * With wintun we are only interested in read event. Ring buffer is
+         * always ready for write, so we don't do wait.
+         */
+        tuntap = EVENT_READ;
+    }
+#endif
+
+    /*
+     * Configure event wait based on socket, tuntap flags.
+     */
+    for (int i = 0; i < c->c1.link_sockets_num; i++)
+    {
+        if (proto_is_dgram(c->c2.link_sockets[i]->info.proto))
+        {
+            socket_set(c->c2.link_sockets[i], multi_io->es, socket,
+                       &c->c2.link_sockets[i]->ev_arg, NULL);
+        }
+    }
+    tun_set(c->c1.tuntap, multi_io->es, tuntap, (void *)tun_shift, NULL);
+
+    multi_io->udp_flags = socket | tuntap;
+}
+
+void
+get_io_flags_udp(struct context *c, struct multi_protocol *multi_io, const unsigned int flags)
+{
+    multi_io->udp_flags = ES_ERROR;
+    if (c->c2.fast_io && (flags & (IOW_TO_TUN | IOW_TO_LINK | IOW_MBUF)))
+    {
+        /* fast path -- only for TUN/TAP/UDP writes */
+        unsigned int ret = 0;
+        if (flags & IOW_TO_TUN)
+        {
+            ret |= TUN_WRITE;
+        }
+        if (flags & (IOW_TO_LINK | IOW_MBUF))
+        {
+            ret |= SOCKET_WRITE;
+        }
+        multi_io->udp_flags = ret;
+    }
+    else
+    {
+#ifdef _WIN32
+        bool skip_iowait = flags & IOW_TO_TUN;
+        if (flags & IOW_READ_TUN)
+        {
+            /*
+             * don't read from tun if we have pending write to link,
+             * since every tun read overwrites to_link buffer filled
+             * by previous tun read
+             */
+            skip_iowait = !(flags & IOW_TO_LINK);
+        }
+        if (tuntap_is_wintun(c->c1.tuntap) && skip_iowait)
+        {
+            unsigned int ret = 0;
+            if (flags & IOW_TO_TUN)
+            {
+                ret |= TUN_WRITE;
+            }
+            if (flags & IOW_READ_TUN)
+            {
+                ret |= TUN_READ;
+            }
+            multi_io->udp_flags = ret;
+        }
+        else
+#endif /* ifdef _WIN32 */
+        {
+            /* slow path - delegate to io_wait_dowork_udp to calculate flags */
+            get_io_flags_dowork_udp(c, multi_io, flags);
+        }
+    }
+}
+
+void
 io_wait_dowork(struct context *c, const unsigned int flags)
 {
     unsigned int socket = 0;
@@ -2295,6 +2462,7 @@ 
     dmsg(D_EVENT_WAIT, "I/O WAIT status=0x%04x", c->c2.event_set_status);
 }
 
+
 void
 process_io(struct context *c, struct link_socket *ls)
 {
diff --git a/src/openvpn/forward.h b/src/openvpn/forward.h
index 3acbdd0..5fb631f 100644
--- a/src/openvpn/forward.h
+++ b/src/openvpn/forward.h
@@ -69,6 +69,10 @@ 
 
 extern counter_type link_write_bytes_global;
 
+void get_io_flags_dowork_udp(struct context *c, struct multi_protocol *multi_io, const unsigned int flags);
+
+void get_io_flags_udp(struct context *c, struct multi_protocol *multi_io, const unsigned int flags);
+
 void io_wait_dowork(struct context *c, const unsigned int flags);
 
 void pre_select(struct context *c);
diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 6f21752..c817ce6 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -3756,6 +3756,24 @@ 
     unsigned int sockflags = c->options.sockflags;
     int i;
 
+    int mode = LS_MODE_DEFAULT;
+    /* mode allows CM_CHILD_TCP
+     * instances to inherit acceptable fds
+     * from a top-level parent */
+    if (c->options.mode == MODE_SERVER)
+    {
+        /* initializing listening socket */
+        if (c->mode == CM_TOP)
+        {
+            mode = LS_MODE_TCP_LISTEN;
+        }
+        /* initializing socket to client */
+        else if (c->mode == CM_CHILD_TCP)
+        {
+            mode = LS_MODE_TCP_ACCEPT_FROM;
+        }
+    }
+
 #if PORT_SHARE
     if (c->options.port_share_host && c->options.port_share_port)
     {
@@ -3765,33 +3783,37 @@ 
 
     for (i = 0; i < c->c1.link_sockets_num; i++)
     {
-        int mode = LS_MODE_DEFAULT;
+        const char *host = c->options.ce.local_list->array[i]->local;
+        const char *port = c->options.ce.local_list->array[i]->port;
+        int proto = c->options.ce.local_list->array[i]->proto;
+        bool bind_local = c->options.ce.local_list->array[i]->bind_local;
 
-        /* mode allows CM_CHILD_TCP
-         * instances to inherit acceptable fds
-         * from a top-level parent */
-        if (c->options.mode == MODE_SERVER)
+        if (c->mode == CM_CHILD_TCP || c->mode == CM_CHILD_UDP)
         {
-            /* initializing listening socket */
-            if (c->mode == CM_TOP)
+            const struct link_socket *ls = NULL;
+            if (c->mode == CM_CHILD_TCP)
             {
-                mode = LS_MODE_TCP_LISTEN;
+                ls = c->c2.accept_from;
             }
-            /* initializing socket to client */
-            else if (c->mode == CM_CHILD_TCP)
+            else if (c->mode == CM_CHILD_UDP)
             {
-                mode = LS_MODE_TCP_ACCEPT_FROM;
+                ls = c->c2.link_sockets[0];
             }
+
+            host = ls->local_host;
+            port = ls->local_port;
+            proto = ls->info.proto;
+            bind_local = ls->bind_local;
         }
 
         /* init each socket with its specific port */
         link_socket_init_phase1(c->c2.link_sockets[i],
-                                c->options.ce.local_list->array[i]->local,
-                                c->options.ce.local_list->array[i]->port,
+                                host,
+                                port,
                                 c->options.ce.remote,
                                 c->options.ce.remote_port,
                                 c->c1.dns_cache,
-                                c->options.ce.proto,
+                                proto,
                                 c->options.ce.af,
                                 c->options.ce.bind_ipv6_only,
                                 mode,
@@ -3801,7 +3823,7 @@ 
 #ifdef ENABLE_DEBUG
                                 c->options.gremlin,
 #endif
-                                c->options.ce.local_list->array[i]->bind_local,
+                                bind_local,
                                 c->options.ce.remote_float,
                                 &c->c1.link_socket_addrs[i],
                                 c->options.ipchange,
@@ -4612,7 +4634,7 @@ 
     }
 
     /* our wait-for-i/o objects, different for posix vs. win32 */
-    if (c->mode == CM_P2P)
+    if (c->mode == CM_P2P || c->mode == CM_TOP)
     {
         do_event_set_init(c, SHAPER_DEFINED(&c->options));
     }
@@ -4876,7 +4898,7 @@ 
     CLEAR(*dest);
 
     /* proto_is_dgram will ASSERT(0) if proto is invalid */
-    dest->mode = proto_is_dgram(src->options.ce.proto) ? CM_CHILD_UDP : CM_CHILD_TCP;
+    dest->mode = proto_is_dgram(ls->info.proto) ? CM_CHILD_UDP : CM_CHILD_TCP;
 
     dest->gc = gc_new();
 
@@ -4904,6 +4926,8 @@ 
     dest->options = src->options;
     options_detach(&dest->options);
 
+    dest->c2.event_set = src->c2.event_set;
+
     if (dest->mode == CM_CHILD_TCP)
     {
         /*
diff --git a/src/openvpn/mroute.c b/src/openvpn/mroute.c
index f4539dc..6c8e8dd 100644
--- a/src/openvpn/mroute.c
+++ b/src/openvpn/mroute.c
@@ -421,6 +421,7 @@ 
                 {
                     buf_printf(&out, ":%d", ntohs(maddr.v4.port));
                 }
+                buf_printf(&out, ":%d", maddr.proto);
             }
             break;
 
diff --git a/src/openvpn/mroute.h b/src/openvpn/mroute.h
index 8b457d4..fd1dbfe 100644
--- a/src/openvpn/mroute.h
+++ b/src/openvpn/mroute.h
@@ -76,6 +76,7 @@ 
     uint8_t len;    /* length of address */
     uint8_t unused;
     uint8_t type;   /* MR_ADDR/MR_WITH flags */
+    uint8_t proto;
     uint8_t netbits; /* number of bits in network part of address,
                       * valid if MR_WITH_NETBITS is set */
     union {
@@ -201,6 +202,10 @@ 
     {
         return false;
     }
+    if (a1->proto != a2->proto)
+    {
+        return false;
+    }
     if (a1->netbits != a2->netbits)
     {
         return false;
@@ -222,7 +227,7 @@ 
 static inline uint32_t
 mroute_addr_hash_len(const struct mroute_addr *a)
 {
-    return (uint32_t) a->len + 2;
+    return (uint32_t) a->len + 3;
 }
 
 static inline void
diff --git a/src/openvpn/mtcp.c b/src/openvpn/mtcp.c
index 29706d0..73f6bcc 100644
--- a/src/openvpn/mtcp.c
+++ b/src/openvpn/mtcp.c
@@ -54,7 +54,7 @@ 
     struct hash *hash = m->hash;
 
     mi = multi_create_instance(m, NULL, ls);
-    if (mi)
+    if (mi && !proto_is_dgram(ls->info.proto))
     {
         struct hash_element *he;
         const uint32_t hv = hash_value(hash, &mi->real);
@@ -241,87 +241,3 @@ 
     }
     return ret;
 }
-
-/*
- * Top level event loop for single-threaded operation.
- * TCP mode.
- */
-void
-tunnel_server_tcp(struct context *top)
-{
-    struct multi_context multi;
-    int status;
-
-    top->mode = CM_TOP;
-    context_clear_2(top);
-
-    /* initialize top-tunnel instance */
-    init_instance_handle_signals(top, top->es, CC_HARD_USR1_TO_HUP);
-    if (IS_SIG(top))
-    {
-        return;
-    }
-
-    /* initialize global multi_context object */
-    multi_init(&multi, top, true);
-
-    /* initialize our cloned top object */
-    multi_top_init(&multi, top);
-
-    /* initialize management interface */
-    init_management_callback_multi(&multi);
-
-    /* finished with initialization */
-    initialization_sequence_completed(top, ISC_SERVER); /* --mode server --proto tcp-server */
-
-#ifdef ENABLE_ASYNC_PUSH
-    multi.top.c2.inotify_fd = inotify_init();
-    if (multi.top.c2.inotify_fd < 0)
-    {
-        msg(D_MULTI_ERRORS | M_ERRNO, "MULTI: inotify_init error");
-    }
-#endif
-
-    /* per-packet event loop */
-    while (true)
-    {
-        perf_push(PERF_EVENT_LOOP);
-
-        /* wait on tun/socket list */
-        multi_get_timeout(&multi, &multi.top.c2.timeval);
-        status = multi_protocol_io_wait(&multi);
-        MULTI_CHECK_SIG(&multi);
-
-        /* check on status of coarse timers */
-        multi_process_per_second_timers(&multi);
-
-        /* timeout? */
-        if (status > 0)
-        {
-            /* process the I/O which triggered select */
-            multi_protocol_process_io(&multi);
-            MULTI_CHECK_SIG(&multi);
-        }
-        else if (status == 0)
-        {
-            multi_protocol_action(&multi, NULL, TA_TIMEOUT, false);
-        }
-
-        perf_pop();
-    }
-
-#ifdef ENABLE_ASYNC_PUSH
-    close(top->c2.inotify_fd);
-#endif
-
-    /* shut down management interface */
-    uninit_management_callback();
-
-    /* save ifconfig-pool */
-    multi_ifconfig_pool_persist(&multi, true);
-
-    /* tear down tunnel instance (unless --persist-tun) */
-    multi_uninit(&multi);
-    multi_top_free(&multi);
-    close_instance(top);
-}
diff --git a/src/openvpn/mtcp.h b/src/openvpn/mtcp.h
index e48481a..1cc1a51 100644
--- a/src/openvpn/mtcp.h
+++ b/src/openvpn/mtcp.h
@@ -51,17 +51,6 @@ 
 
 void multi_tcp_link_out_deferred(struct multi_context *m, struct multi_instance *mi);
 
-
-/**************************************************************************/
-/**
- * Main event loop for OpenVPN in TCP server mode.
- * @ingroup eventloop
- *
- * @param top - Top-level context structure.
- */
-void tunnel_server_tcp(struct context *top);
-
-
 void multi_tcp_delete_event(struct multi_protocol *multi_io, event_t event);
 
 #endif /* ifndef MTCP_H */
diff --git a/src/openvpn/mudp.c b/src/openvpn/mudp.c
index 37af88e..a7e6e1d 100644
--- a/src/openvpn/mudp.c
+++ b/src/openvpn/mudp.c
@@ -192,6 +192,7 @@ 
     struct mroute_addr real = {0};
     struct multi_instance *mi = NULL;
     struct hash *hash = m->hash;
+    real.proto = ls->info.proto;
 
     if (mroute_extract_openvpn_sockaddr(&real, &m->top.c2.from.dest, true)
         && m->top.c2.buf.len > 0)
@@ -318,18 +319,66 @@ 
         msg_set_prefix("Connection Attempt");
         m->top.c2.to_link = m->hmac_reply;
         m->top.c2.to_link_addr = m->hmac_reply_dest;
-        process_outgoing_link(&m->top, m->top.c2.link_sockets[0]);
+        for (int i = 0; i < m->top.c1.link_sockets_num; i++)
+        {
+            if (!proto_is_dgram(m->top.c2.link_sockets[i]->info.proto))
+            {
+                continue;
+            }
+
+            process_outgoing_link(&m->top, m->top.c2.link_sockets[i]);
+        }
         m->hmac_reply_dest = NULL;
     }
 }
 
 /*
+ * Return the io_wait() flags appropriate for
+ * a point-to-multipoint tunnel.
+ */
+unsigned int
+p2mp_iow_flags(const struct multi_context *m)
+{
+    unsigned int flags = IOW_WAIT_SIGNAL;
+    if (m->pending)
+    {
+        if (TUN_OUT(&m->pending->context))
+        {
+            flags |= IOW_TO_TUN;
+        }
+        if (LINK_OUT(&m->pending->context))
+        {
+            flags |= IOW_TO_LINK;
+        }
+    }
+    else if (mbuf_defined(m->mbuf))
+    {
+        flags |= IOW_MBUF;
+    }
+    else if (m->hmac_reply_dest)
+    {
+        flags |= IOW_TO_LINK;
+    }
+    else
+    {
+        flags |= IOW_READ;
+    }
+#ifdef _WIN32
+    if (tuntap_ring_empty(m->top.c1.tuntap))
+    {
+        flags &= ~IOW_READ_TUN;
+    }
+#endif
+    return flags;
+}
+
+/*
  * Process an I/O event.
  */
-static void
+void
 multi_process_io_udp(struct multi_context *m)
 {
-    const unsigned int status = m->top.c2.event_set_status;
+    const unsigned int status = m->multi_io->udp_flags;
     const unsigned int mpp_flags = m->top.c2.fast_io
                                    ? (MPP_CONDITIONAL_PRE_SELECT | MPP_CLOSE_ON_SIGNAL)
                                    : (MPP_PRE_SELECT | MPP_CLOSE_ON_SIGNAL);
@@ -427,123 +476,3 @@ 
     }
 #endif
 }
-
-/*
- * Return the io_wait() flags appropriate for
- * a point-to-multipoint tunnel.
- */
-static inline unsigned int
-p2mp_iow_flags(const struct multi_context *m)
-{
-    unsigned int flags = IOW_WAIT_SIGNAL;
-    if (m->pending)
-    {
-        if (TUN_OUT(&m->pending->context))
-        {
-            flags |= IOW_TO_TUN;
-        }
-        if (LINK_OUT(&m->pending->context))
-        {
-            flags |= IOW_TO_LINK;
-        }
-    }
-    else if (mbuf_defined(m->mbuf))
-    {
-        flags |= IOW_MBUF;
-    }
-    else if (m->hmac_reply_dest)
-    {
-        flags |= IOW_TO_LINK;
-    }
-    else
-    {
-        flags |= IOW_READ;
-    }
-#ifdef _WIN32
-    if (tuntap_ring_empty(m->top.c1.tuntap))
-    {
-        flags &= ~IOW_READ_TUN;
-    }
-#endif
-    return flags;
-}
-
-
-void
-tunnel_server_udp(struct context *top)
-{
-    struct multi_context multi;
-
-    top->mode = CM_TOP;
-    context_clear_2(top);
-
-    /* initialize top-tunnel instance */
-    init_instance_handle_signals(top, top->es, CC_HARD_USR1_TO_HUP);
-    if (IS_SIG(top))
-    {
-        return;
-    }
-
-    /* initialize global multi_context object */
-    multi_init(&multi, top, false);
-
-    /* initialize our cloned top object */
-    multi_top_init(&multi, top);
-
-    /* initialize management interface */
-    init_management_callback_multi(&multi);
-
-    /* finished with initialization */
-    initialization_sequence_completed(top, ISC_SERVER); /* --mode server --proto udp */
-
-#ifdef ENABLE_ASYNC_PUSH
-    multi.top.c2.inotify_fd = inotify_init();
-    if (multi.top.c2.inotify_fd < 0)
-    {
-        msg(D_MULTI_ERRORS | M_ERRNO, "MULTI: inotify_init error");
-    }
-#endif
-
-    /* per-packet event loop */
-    while (true)
-    {
-        perf_push(PERF_EVENT_LOOP);
-
-        /* set up and do the io_wait() */
-        multi_get_timeout(&multi, &multi.top.c2.timeval);
-        io_wait(&multi.top, p2mp_iow_flags(&multi));
-        MULTI_CHECK_SIG(&multi);
-
-        /* check on status of coarse timers */
-        multi_process_per_second_timers(&multi);
-
-        /* timeout? */
-        if (multi.top.c2.event_set_status == ES_TIMEOUT)
-        {
-            multi_process_timeout(&multi, MPP_PRE_SELECT|MPP_CLOSE_ON_SIGNAL);
-        }
-        else
-        {
-            /* process I/O */
-            multi_process_io_udp(&multi);
-            MULTI_CHECK_SIG(&multi);
-        }
-
-        perf_pop();
-    }
-
-#ifdef ENABLE_ASYNC_PUSH
-    close(top->c2.inotify_fd);
-#endif
-
-    /* shut down management interface */
-    uninit_management_callback();
-
-    /* save ifconfig-pool */
-    multi_ifconfig_pool_persist(&multi, true);
-
-    /* tear down tunnel instance (unless --persist-tun) */
-    multi_uninit(&multi);
-    multi_top_free(&multi);
-    close_instance(top);
-}
diff --git a/src/openvpn/mudp.h b/src/openvpn/mudp.h
index b378754..68d2d6d 100644
--- a/src/openvpn/mudp.h
+++ b/src/openvpn/mudp.h
@@ -31,18 +31,9 @@ 
 struct context;
 struct multi_context;
 
+unsigned int p2mp_iow_flags(const struct multi_context *m);
 
-/**
- * Main event loop for OpenVPN in UDP server mode.
- * @ingroup eventloop
- *
- * This function implements OpenVPN's main event loop for UDP server mode.
- *
- * @param top - Top-level context structure.
- */
-void tunnel_server_udp(struct context *top);
-
-
+void multi_process_io_udp(struct multi_context *m);
 /**************************************************************************/
 /**
  * Get, and if necessary create, the multi_instance associated with a
diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c
index d7b4e3b..2d4fbe7 100644
--- a/src/openvpn/multi.c
+++ b/src/openvpn/multi.c
@@ -289,7 +289,7 @@ 
  * Main initialization function, init multi_context object.
  */
 void
-multi_init(struct multi_context *m, struct context *t, bool tcp_mode)
+multi_init(struct multi_context *m, struct context *t)
 {
     int dev = DEV_TYPE_UNDEF;
 
@@ -435,13 +435,12 @@ 
 
     m->instances = calloc(m->max_clients, sizeof(struct multi_instance *));
 
+    m->top.c2.event_set = t->c2.event_set;
+
     /*
-     * Initialize multi-socket TCP I/O wait object
+     * Initialize multi-socket I/O wait object
      */
-    if (tcp_mode)
-    {
-        m->multi_io = multi_protocol_init(t->options.max_clients, &m->max_clients);
-    }
+    m->multi_io = multi_protocol_init(t->options.max_clients, &m->max_clients);
     m->tcp_queue_limit = t->options.tcp_queue_limit;
 
     /*
@@ -665,7 +664,7 @@ 
             mi->did_iroutes = false;
         }
 
-        if (m->multi_io)
+        if (m->multi_io && !proto_is_dgram(m->top.options.ce.proto))
         {
             multi_tcp_dereference_instance(m->multi_io, mi);
         }
@@ -776,7 +775,6 @@ 
         mi->real = *real;
         generate_prefix(mi);
     }
-
     mi->did_open_context = true;
     inherit_context_child(&mi->context, &m->top, ls);
     if (IS_SIG(&mi->context))
@@ -798,6 +796,7 @@ 
         {
             goto err;
         }
+        mi->real.proto = ls->info.proto;
         generate_prefix(mi);
     }
 
@@ -4158,6 +4157,98 @@ 
     ASSERT(mi->context.c2.tls_multi->peer_id < m->max_clients);
 }
 
+/**************************************************************************/
+/**
+ * Main event loop for OpenVPN in multi-protocol server mode.
+ * @ingroup eventloop
+ *
+ * @param top - Top-level context structure.
+ */
+void
+tunnel_server_loop(struct multi_context *multi)
+{
+    int status;
+
+    while (true)
+    {
+        perf_push(PERF_EVENT_LOOP);
+
+        /* wait on tun/socket list */
+        multi_get_timeout(multi, &multi->top.c2.timeval);
+        status = multi_protocol_io_wait(multi);
+        MULTI_CHECK_SIG(multi);
+
+        /* check on status of coarse timers */
+        multi_process_per_second_timers(multi);
+
+        /* timeout? */
+        if (status > 0)
+        {
+            /* process the I/O which triggered select */
+            multi_protocol_process_io(multi);
+            MULTI_CHECK_SIG(multi);
+        }
+        else if (status == 0)
+        {
+            multi_protocol_action(multi, NULL, TA_TIMEOUT, false);
+        }
+
+        perf_pop();
+    }
+}
+
+void
+tunnel_server_init(struct context *top)
+{
+    struct multi_context multi;
+
+    top->mode = CM_TOP;
+    context_clear_2(top);
+
+    /* initialize top-tunnel instance */
+    init_instance_handle_signals(top, top->es, CC_HARD_USR1_TO_HUP);
+    if (IS_SIG(top))
+    {
+        return;
+    }
+
+    /* initialize global multi_context object */
+    multi_init(&multi, top);
+
+    /* initialize our cloned top object */
+    multi_top_init(&multi, top);
+
+    /* initialize management interface */
+    init_management_callback_multi(&multi);
+
+    /* finished with initialization */
+    initialization_sequence_completed(top, ISC_SERVER); /* --mode server --proto tcp-server */
+
+#ifdef ENABLE_ASYNC_PUSH
+    multi.top.c2.inotify_fd = inotify_init();
+    if (multi.top.c2.inotify_fd < 0)
+    {
+        msg(D_MULTI_ERRORS | M_ERRNO, "MULTI: inotify_init error");
+    }
+#endif
+
+    tunnel_server_loop(&multi);
+
+    #ifdef ENABLE_ASYNC_PUSH
+    close(top->c2.inotify_fd);
+#endif
+
+    /* shut down management interface */
+    uninit_management_callback();
+
+    /* save ifconfig-pool */
+    multi_ifconfig_pool_persist(&multi, true);
+
+    /* tear down tunnel instance (unless --persist-tun) */
+    multi_uninit(&multi);
+    multi_top_free(&multi);
+    close_instance(top);
+}
 
 /*
  * Top level event loop.
@@ -4167,12 +4258,6 @@ 
 {
     ASSERT(top->options.mode == MODE_SERVER);
 
-    if (proto_is_dgram(top->options.ce.proto))
-    {
-        tunnel_server_udp(top);
-    }
-    else
-    {
-        tunnel_server_tcp(top);
-    }
+    tunnel_server_init(top);
+
 }
diff --git a/src/openvpn/multi.h b/src/openvpn/multi.h
index a25aeda..65fd320 100644
--- a/src/openvpn/multi.h
+++ b/src/openvpn/multi.h
@@ -247,10 +247,8 @@ 
  * Main event loop for OpenVPN in server mode.
  * @ingroup eventloop
  *
- * This function calls the appropriate main event loop function depending
- * on the transport protocol used:
- *  - \c tunnel_server_udp()
- *  - \c tunnel_server_tcp()
+ * This function calls the main event loop function
+ * on the transport protocols:
  *
  * @param top          - Top-level context structure.
  */
@@ -263,7 +261,7 @@ 
  * Called by mtcp.c, mudp.c, or other (to be written) protocol drivers
  */
 
-void multi_init(struct multi_context *m, struct context *t, bool tcp_mode);
+void multi_init(struct multi_context *m, struct context *t);
 
 void multi_uninit(struct multi_context *m);
 
@@ -659,9 +657,12 @@ 
 multi_process_outgoing_tun(struct multi_context *m, const unsigned int mpp_flags)
 {
     struct multi_instance *mi = m->pending;
+    if (!mi)
+    {
+        return false;
+    }
     bool ret = true;
 
-    ASSERT(mi);
 #ifdef MULTI_DEBUG_EVENT_LOOP
     printf("%s -> TUN len=%d\n",
            id(mi),
diff --git a/src/openvpn/openvpn.h b/src/openvpn/openvpn.h
index 77bb41d..821ac2e 100644
--- a/src/openvpn/openvpn.h
+++ b/src/openvpn/openvpn.h
@@ -220,8 +220,8 @@ 
  * \c SIGUSR1 restarts.
  *
  * This structure is initialized at the top of the \c
- * tunnel_point_to_point(), \c tunnel_server_udp(), and \c
- * tunnel_server_tcp() functions.  In other words, it is reset for every
+ * tunnel_point_to_point(), \c tunnel_server() \c
+ * functions.  In other words, it is reset for every
  * iteration of the \c main() function's inner \c SIGUSR1 loop.
  */
 struct context_2
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 25bdd44..42210da 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -2199,6 +2199,7 @@ 
     }
 
     ALLOC_OBJ_CLEAR_GC(e, struct local_entry, gc);
+    e->proto = PROTO_NONE;
     l->array[l->len++] = e;
 
     return e;
@@ -3170,14 +3171,30 @@ 
         if (ce->proto == PROTO_TCP)
         {
             ce->proto = PROTO_TCP_SERVER;
+            o->ce.proto = ce->proto;
+        }
+        if (ce->local_list)
+        {
+            for (int i = 0; i < ce->local_list->len; i++)
+            {
+                if (ce->local_list->array[i]->proto == PROTO_TCP)
+                {
+                    ce->local_list->array[i]->proto = PROTO_TCP_SERVER;
+                }
+                else if (ce->local_list->array[i]->proto == PROTO_NONE)
+                {
+                    ce->local_list->array[i]->proto = ce->proto;
+                }
+            }
         }
     }
 
-    if (o->client)
+    if (o->mode != MODE_SERVER)
     {
         if (ce->proto == PROTO_TCP)
         {
             ce->proto = PROTO_TCP_CLIENT;
+            o->ce.proto = ce->proto;
         }
     }
 
@@ -3331,6 +3348,10 @@ 
     {
         le->port = o->ce.local_port;
     }
+    if (!le->proto)
+    {
+        le->proto = o->ce.proto;
+    }
 }
 
 #ifdef _WIN32
@@ -3822,6 +3843,7 @@ 
         ASSERT(e);
         e->port = o->ce.local_port;
         e->bind_local = o->ce.bind_local;
+        e->proto = o->ce.proto;
     }
 
     /* use the same listen list for every outgoing connection */
@@ -6232,7 +6254,7 @@ 
         VERIFY_PERMISSION(OPT_P_UP);
         options->ifconfig_nowarn = true;
     }
-    else if (streq(p[0], "local") && p[1] && !p[3])
+    else if (streq(p[0], "local") && p[1] && !p[4])
     {
         struct local_entry *e;
 
@@ -6253,7 +6275,12 @@ 
         if (p[2])
         {
             e->port = p[2];
-            e->bind_local = true;
+            /*e->bind_local = true; */
+        }
+
+        if (p[3])
+        {
+            e->proto = ascii2proto(p[3]);
         }
     }
     else if (streq(p[0], "remote-random") && !p[1])
diff --git a/src/openvpn/options.h b/src/openvpn/options.h
index 6942455..f3cf7e5 100644
--- a/src/openvpn/options.h
+++ b/src/openvpn/options.h
@@ -99,6 +99,7 @@ 
     const char *local;
     const char *port;
     bool bind_local;
+    int proto;
 };
 
 struct connection_entry