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-rw-r--r--mtcp.c727
1 files changed, 727 insertions, 0 deletions
diff --git a/mtcp.c b/mtcp.c
new file mode 100644
index 0000000..a71801f
--- /dev/null
+++ b/mtcp.c
@@ -0,0 +1,727 @@
+/*
+ * OpenVPN -- An application to securely tunnel IP networks
+ * over a single TCP/UDP port, with support for SSL/TLS-based
+ * session authentication and key exchange,
+ * packet encryption, packet authentication, and
+ * packet compression.
+ *
+ * Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (see the file COPYING included with this
+ * distribution); if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifdef WIN32
+#include "config-win32.h"
+#else
+#include "config.h"
+#endif
+
+#include "syshead.h"
+
+#if P2MP_SERVER
+
+#include "multi.h"
+#include "forward-inline.h"
+
+#include "memdbg.h"
+
+/*
+ * TCP States
+ */
+#define TA_UNDEF 0
+#define TA_SOCKET_READ 1
+#define TA_SOCKET_READ_RESIDUAL 2
+#define TA_SOCKET_WRITE 3
+#define TA_SOCKET_WRITE_READY 4
+#define TA_SOCKET_WRITE_DEFERRED 5
+#define TA_TUN_READ 6
+#define TA_TUN_WRITE 7
+#define TA_INITIAL 8
+#define TA_TIMEOUT 9
+#define TA_TUN_WRITE_TIMEOUT 10
+
+/*
+ * Special tags passed to event.[ch] functions
+ */
+#define MTCP_SOCKET ((void*)1)
+#define MTCP_TUN ((void*)2)
+#define MTCP_SIG ((void*)3) /* Only on Windows */
+#ifdef ENABLE_MANAGEMENT
+# define MTCP_MANAGEMENT ((void*)4)
+#endif
+
+#define MTCP_N ((void*)16) /* upper bound on MTCP_x */
+
+struct ta_iow_flags
+{
+ unsigned int flags;
+ unsigned int ret;
+ unsigned int tun;
+ unsigned int sock;
+};
+
+static const char *
+pract (int action)
+{
+ switch (action)
+ {
+ case TA_UNDEF:
+ return "TA_UNDEF";
+ case TA_SOCKET_READ:
+ return "TA_SOCKET_READ";
+ case TA_SOCKET_READ_RESIDUAL:
+ return "TA_SOCKET_READ_RESIDUAL";
+ case TA_SOCKET_WRITE:
+ return "TA_SOCKET_WRITE";
+ case TA_SOCKET_WRITE_READY:
+ return "TA_SOCKET_WRITE_READY";
+ case TA_SOCKET_WRITE_DEFERRED:
+ return "TA_SOCKET_WRITE_DEFERRED";
+ case TA_TUN_READ:
+ return "TA_TUN_READ";
+ case TA_TUN_WRITE:
+ return "TA_TUN_WRITE";
+ case TA_INITIAL:
+ return "TA_INITIAL";
+ case TA_TIMEOUT:
+ return "TA_TIMEOUT";
+ case TA_TUN_WRITE_TIMEOUT:
+ return "TA_TUN_WRITE_TIMEOUT";
+ default:
+ return "?";
+ }
+}
+
+static struct multi_instance *
+multi_create_instance_tcp (struct multi_context *m)
+{
+ struct gc_arena gc = gc_new ();
+ struct multi_instance *mi = NULL;
+ struct hash *hash = m->hash;
+
+ mi = multi_create_instance (m, NULL);
+ if (mi)
+ {
+ struct hash_element *he;
+ const uint32_t hv = hash_value (hash, &mi->real);
+ struct hash_bucket *bucket = hash_bucket (hash, hv);
+
+ hash_bucket_lock (bucket);
+ he = hash_lookup_fast (hash, bucket, &mi->real, hv);
+
+ if (he)
+ {
+ struct multi_instance *oldmi = (struct multi_instance *) he->value;
+ msg (D_MULTI_LOW, "MULTI TCP: new incoming client address matches existing client address -- new client takes precedence");
+ oldmi->did_real_hash = false;
+ multi_close_instance (m, oldmi, false);
+ he->key = &mi->real;
+ he->value = mi;
+ }
+ else
+ hash_add_fast (hash, bucket, &mi->real, hv, mi);
+
+ mi->did_real_hash = true;
+
+ hash_bucket_unlock (bucket);
+ }
+
+#ifdef ENABLE_DEBUG
+ if (mi)
+ dmsg (D_MULTI_DEBUG, "MULTI TCP: instance added: %s", mroute_addr_print (&mi->real, &gc));
+ else
+ dmsg (D_MULTI_DEBUG, "MULTI TCP: new client instance failed");
+#endif
+
+ gc_free (&gc);
+ ASSERT (!(mi && mi->halt));
+ return mi;
+}
+
+bool
+multi_tcp_instance_specific_init (struct multi_context *m, struct multi_instance *mi)
+{
+ /* buffer for queued TCP socket output packets */
+ mi->tcp_link_out_deferred = mbuf_init (m->top.options.n_bcast_buf);
+
+ ASSERT (mi->context.c2.link_socket);
+ ASSERT (mi->context.c2.link_socket->info.lsa);
+ ASSERT (mi->context.c2.link_socket->mode == LS_MODE_TCP_ACCEPT_FROM);
+ if (!mroute_extract_sockaddr_in (&mi->real, &mi->context.c2.link_socket->info.lsa->actual, true))
+ {
+ msg (D_MULTI_ERRORS, "MULTI TCP: TCP client address is undefined");
+ return false;
+ }
+ return true;
+}
+
+void
+multi_tcp_instance_specific_free (struct multi_instance *mi)
+{
+ mbuf_free (mi->tcp_link_out_deferred);
+}
+
+struct multi_tcp *
+multi_tcp_init (int maxevents, int *maxclients)
+{
+ struct multi_tcp *mtcp;
+ const int extra_events = BASE_N_EVENTS;
+
+ ASSERT (maxevents >= 1);
+ ASSERT (maxclients);
+
+ ALLOC_OBJ_CLEAR (mtcp, struct multi_tcp);
+ mtcp->maxevents = maxevents + extra_events;
+ mtcp->es = event_set_init (&mtcp->maxevents, 0);
+ wait_signal (mtcp->es, MTCP_SIG);
+ ALLOC_ARRAY (mtcp->esr, struct event_set_return, mtcp->maxevents);
+ *maxclients = max_int (min_int (mtcp->maxevents - extra_events, *maxclients), 1);
+ msg (D_MULTI_LOW, "MULTI: TCP INIT maxclients=%d maxevents=%d", *maxclients, mtcp->maxevents);
+ return mtcp;
+}
+
+void
+multi_tcp_delete_event (struct multi_tcp *mtcp, event_t event)
+{
+ if (mtcp && mtcp->es)
+ event_del (mtcp->es, event);
+}
+
+void
+multi_tcp_free (struct multi_tcp *mtcp)
+{
+ if (mtcp)
+ {
+ event_free (mtcp->es);
+ if (mtcp->esr)
+ free (mtcp->esr);
+ free (mtcp);
+ }
+}
+
+void
+multi_tcp_dereference_instance (struct multi_tcp *mtcp, struct multi_instance *mi)
+{
+ struct link_socket *ls = mi->context.c2.link_socket;
+ if (ls && mi->socket_set_called)
+ event_del (mtcp->es, socket_event_handle (ls));
+ mtcp->n_esr = 0;
+}
+
+static inline void
+multi_tcp_set_global_rw_flags (struct multi_context *m, struct multi_instance *mi)
+{
+ if (mi)
+ {
+ mi->socket_set_called = true;
+ socket_set (mi->context.c2.link_socket,
+ m->mtcp->es,
+ mbuf_defined (mi->tcp_link_out_deferred) ? EVENT_WRITE : EVENT_READ,
+ mi,
+ &mi->tcp_rwflags);
+ }
+}
+
+static inline int
+multi_tcp_wait (const struct context *c,
+ struct multi_tcp *mtcp)
+{
+ int status;
+ socket_set_listen_persistent (c->c2.link_socket, mtcp->es, MTCP_SOCKET);
+ tun_set (c->c1.tuntap, mtcp->es, EVENT_READ, MTCP_TUN, &mtcp->tun_rwflags);
+#ifdef ENABLE_MANAGEMENT
+ if (management)
+ management_socket_set (management, mtcp->es, MTCP_MANAGEMENT, &mtcp->management_persist_flags);
+#endif
+ status = event_wait (mtcp->es, &c->c2.timeval, mtcp->esr, mtcp->maxevents);
+ update_time ();
+ mtcp->n_esr = 0;
+ if (status > 0)
+ mtcp->n_esr = status;
+ return status;
+}
+
+static inline struct context *
+multi_tcp_context (struct multi_context *m, struct multi_instance *mi)
+{
+ if (mi)
+ return &mi->context;
+ else
+ return &m->top;
+}
+
+static bool
+multi_tcp_process_outgoing_link_ready (struct multi_context *m, struct multi_instance *mi, const unsigned int mpp_flags)
+{
+ struct mbuf_item item;
+ bool ret = true;
+ ASSERT (mi);
+
+ /* extract from queue */
+ if (mbuf_extract_item (mi->tcp_link_out_deferred, &item, true)) /* ciphertext IP packet */
+ {
+ dmsg (D_MULTI_TCP, "MULTI TCP: transmitting previously deferred packet");
+
+ ASSERT (mi == item.instance);
+ mi->context.c2.to_link = item.buffer->buf;
+ ret = multi_process_outgoing_link_dowork (m, mi, mpp_flags);
+ if (!ret)
+ mi = NULL;
+ mbuf_free_buf (item.buffer);
+ }
+ return ret;
+}
+
+static bool
+multi_tcp_process_outgoing_link (struct multi_context *m, bool defer, const unsigned int mpp_flags)
+{
+ struct multi_instance *mi = multi_process_outgoing_link_pre (m);
+ bool ret = true;
+
+ if (mi)
+ {
+ if (defer || mbuf_defined (mi->tcp_link_out_deferred))
+ {
+ /* save to queue */
+ struct buffer *buf = &mi->context.c2.to_link;
+ if (BLEN (buf) > 0)
+ {
+ struct mbuf_buffer *mb = mbuf_alloc_buf (buf);
+ struct mbuf_item item;
+
+ set_prefix (mi);
+ dmsg (D_MULTI_TCP, "MULTI TCP: queuing deferred packet");
+ item.buffer = mb;
+ item.instance = mi;
+ mbuf_add_item (mi->tcp_link_out_deferred, &item);
+ mbuf_free_buf (mb);
+ buf_reset (buf);
+ ret = multi_process_post (m, mi, mpp_flags);
+ if (!ret)
+ mi = NULL;
+ clear_prefix ();
+ }
+ }
+ else
+ {
+ ret = multi_process_outgoing_link_dowork (m, mi, mpp_flags);
+ if (!ret)
+ mi = NULL;
+ }
+ }
+ return ret;
+}
+
+static int
+multi_tcp_wait_lite (struct multi_context *m, struct multi_instance *mi, const int action, bool *tun_input_pending)
+{
+ struct context *c = multi_tcp_context (m, mi);
+ unsigned int looking_for = 0;
+
+ dmsg (D_MULTI_DEBUG, "MULTI TCP: multi_tcp_wait_lite a=%s mi=" ptr_format,
+ pract(action),
+ (ptr_type)mi);
+
+ tv_clear (&c->c2.timeval); /* ZERO-TIMEOUT */
+
+ switch (action)
+ {
+ case TA_TUN_READ:
+ looking_for = TUN_READ;
+ tun_input_pending = NULL;
+ io_wait (c, IOW_READ_TUN);
+ break;
+ case TA_SOCKET_READ:
+ looking_for = SOCKET_READ;
+ tun_input_pending = NULL;
+ io_wait (c, IOW_READ_LINK);
+ break;
+ case TA_TUN_WRITE:
+ looking_for = TUN_WRITE;
+ tun_input_pending = NULL;
+ c->c2.timeval.tv_sec = 1; /* For some reason, the Linux 2.2 TUN/TAP driver hits this timeout */
+ perf_push (PERF_PROC_OUT_TUN_MTCP);
+ io_wait (c, IOW_TO_TUN);
+ perf_pop ();
+ break;
+ case TA_SOCKET_WRITE:
+ looking_for = SOCKET_WRITE;
+ io_wait (c, IOW_TO_LINK|IOW_READ_TUN_FORCE);
+ break;
+ default:
+ msg (M_FATAL, "MULTI TCP: multi_tcp_wait_lite, unhandled action=%d", action);
+ }
+
+ if (tun_input_pending && (c->c2.event_set_status & TUN_READ))
+ *tun_input_pending = true;
+
+ if (c->c2.event_set_status & looking_for)
+ {
+ return action;
+ }
+ else
+ {
+ switch (action)
+ {
+ /* TCP socket output buffer is full */
+ case TA_SOCKET_WRITE:
+ return TA_SOCKET_WRITE_DEFERRED;
+
+ /* TUN device timed out on accepting write */
+ case TA_TUN_WRITE:
+ return TA_TUN_WRITE_TIMEOUT;
+ }
+
+ return TA_UNDEF;
+ }
+}
+
+static struct multi_instance *
+multi_tcp_dispatch (struct multi_context *m, struct multi_instance *mi, const int action)
+{
+ const unsigned int mpp_flags = MPP_PRE_SELECT|MPP_RECORD_TOUCH;
+ struct multi_instance *touched = mi;
+ m->mpp_touched = &touched;
+
+ dmsg (D_MULTI_DEBUG, "MULTI TCP: multi_tcp_dispatch a=%s mi=" ptr_format,
+ pract(action),
+ (ptr_type)mi);
+
+ switch (action)
+ {
+ case TA_TUN_READ:
+ read_incoming_tun (&m->top);
+ if (!IS_SIG (&m->top))
+ multi_process_incoming_tun (m, mpp_flags);
+ break;
+ case TA_SOCKET_READ:
+ case TA_SOCKET_READ_RESIDUAL:
+ ASSERT (mi);
+ ASSERT (mi->context.c2.link_socket);
+ set_prefix (mi);
+ read_incoming_link (&mi->context);
+ clear_prefix ();
+ if (!IS_SIG (&mi->context))
+ {
+ multi_process_incoming_link (m, mi, mpp_flags);
+ if (!IS_SIG (&mi->context))
+ stream_buf_read_setup (mi->context.c2.link_socket);
+ }
+ break;
+ case TA_TIMEOUT:
+ multi_process_timeout (m, mpp_flags);
+ break;
+ case TA_TUN_WRITE:
+ multi_process_outgoing_tun (m, mpp_flags);
+ break;
+ case TA_TUN_WRITE_TIMEOUT:
+ multi_process_drop_outgoing_tun (m, mpp_flags);
+ break;
+ case TA_SOCKET_WRITE_READY:
+ ASSERT (mi);
+ multi_tcp_process_outgoing_link_ready (m, mi, mpp_flags);
+ break;
+ case TA_SOCKET_WRITE:
+ multi_tcp_process_outgoing_link (m, false, mpp_flags);
+ break;
+ case TA_SOCKET_WRITE_DEFERRED:
+ multi_tcp_process_outgoing_link (m, true, mpp_flags);
+ break;
+ case TA_INITIAL:
+ ASSERT (mi);
+ multi_tcp_set_global_rw_flags (m, mi);
+ multi_process_post (m, mi, mpp_flags);
+ break;
+ default:
+ msg (M_FATAL, "MULTI TCP: multi_tcp_dispatch, unhandled action=%d", action);
+ }
+
+ m->mpp_touched = NULL;
+ return touched;
+}
+
+int
+multi_tcp_post (struct multi_context *m, struct multi_instance *mi, const int action)
+{
+ struct context *c = multi_tcp_context (m, mi);
+ int newaction = TA_UNDEF;
+
+# define MTP_NONE 0
+# define MTP_TUN_OUT (1<<0)
+# define MTP_LINK_OUT (1<<1)
+ unsigned int flags = MTP_NONE;
+
+ if (TUN_OUT(c))
+ flags |= MTP_TUN_OUT;
+ if (LINK_OUT(c))
+ flags |= MTP_LINK_OUT;
+
+ switch (flags)
+ {
+ case MTP_TUN_OUT|MTP_LINK_OUT:
+ case MTP_TUN_OUT:
+ newaction = TA_TUN_WRITE;
+ break;
+ case MTP_LINK_OUT:
+ newaction = TA_SOCKET_WRITE;
+ break;
+ case MTP_NONE:
+ if (mi && socket_read_residual (c->c2.link_socket))
+ newaction = TA_SOCKET_READ_RESIDUAL;
+ else
+ multi_tcp_set_global_rw_flags (m, mi);
+ break;
+ default:
+ {
+ struct gc_arena gc = gc_new ();
+ msg (M_FATAL, "MULTI TCP: multi_tcp_post bad state, mi=%s flags=%d",
+ multi_instance_string (mi, false, &gc),
+ flags);
+ gc_free (&gc);
+ break;
+ }
+ }
+
+ dmsg (D_MULTI_DEBUG, "MULTI TCP: multi_tcp_post %s -> %s",
+ pract(action),
+ pract(newaction));
+
+ return newaction;
+}
+
+static void
+multi_tcp_action (struct multi_context *m, struct multi_instance *mi, int action, bool poll)
+{
+ bool tun_input_pending = false;
+
+ do {
+ dmsg (D_MULTI_DEBUG, "MULTI TCP: multi_tcp_action a=%s p=%d",
+ pract(action),
+ poll);
+
+ /*
+ * If TA_SOCKET_READ_RESIDUAL, it means we still have pending
+ * input packets which were read by a prior TCP recv.
+ *
+ * Otherwise do a "lite" wait, which means we wait with 0 timeout
+ * on I/O events only related to the current instance, not
+ * the big list of events.
+ *
+ * On our first pass, poll will be false because we already know
+ * that input is available, and to call io_wait would be redundant.
+ */
+ if (poll && action != TA_SOCKET_READ_RESIDUAL)
+ {
+ const int orig_action = action;
+ action = multi_tcp_wait_lite (m, mi, action, &tun_input_pending);
+ if (action == TA_UNDEF)
+ msg (M_FATAL, "MULTI TCP: I/O wait required blocking in multi_tcp_action, action=%d", orig_action);
+ }
+
+ /*
+ * Dispatch the action
+ */
+ {
+ struct multi_instance *touched = multi_tcp_dispatch (m, mi, action);
+
+ /*
+ * Signal received or TCP connection
+ * reset by peer?
+ */
+ if (touched && IS_SIG (&touched->context))
+ {
+ if (mi == touched)
+ mi = NULL;
+ multi_close_instance_on_signal (m, touched);
+ }
+ }
+
+ /*
+ * If dispatch produced any pending output
+ * for a particular instance, point to
+ * that instance.
+ */
+ if (m->pending)
+ mi = m->pending;
+
+ /*
+ * Based on the effects of the action,
+ * such as generating pending output,
+ * possibly transition to a new action state.
+ */
+ action = multi_tcp_post (m, mi, action);
+
+ /*
+ * If we are finished processing the original action,
+ * check if we have any TUN input. If so, transition
+ * our action state to processing this input.
+ */
+ if (tun_input_pending && action == TA_UNDEF)
+ {
+ action = TA_TUN_READ;
+ mi = NULL;
+ tun_input_pending = false;
+ poll = false;
+ }
+ else
+ poll = true;
+
+ } while (action != TA_UNDEF);
+}
+
+static void
+multi_tcp_process_io (struct multi_context *m)
+{
+ struct multi_tcp *mtcp = m->mtcp;
+ int i;
+
+ for (i = 0; i < mtcp->n_esr; ++i)
+ {
+ struct event_set_return *e = &mtcp->esr[i];
+
+ /* incoming data for instance? */
+ if (e->arg >= MTCP_N)
+ {
+ struct multi_instance *mi = (struct multi_instance *) e->arg;
+ if (mi)
+ {
+ if (e->rwflags & EVENT_WRITE)
+ multi_tcp_action (m, mi, TA_SOCKET_WRITE_READY, false);
+ else if (e->rwflags & EVENT_READ)
+ multi_tcp_action (m, mi, TA_SOCKET_READ, false);
+ }
+ }
+ else
+ {
+#ifdef ENABLE_MANAGEMENT
+ if (e->arg == MTCP_MANAGEMENT)
+ {
+ ASSERT (management);
+ management_io (management);
+ }
+ else
+#endif
+ /* incoming data on TUN? */
+ if (e->arg == MTCP_TUN)
+ {
+ if (e->rwflags & EVENT_WRITE)
+ multi_tcp_action (m, NULL, TA_TUN_WRITE, false);
+ else if (e->rwflags & EVENT_READ)
+ multi_tcp_action (m, NULL, TA_TUN_READ, false);
+ }
+ /* new incoming TCP client attempting to connect? */
+ else if (e->arg == MTCP_SOCKET)
+ {
+ struct multi_instance *mi;
+ ASSERT (m->top.c2.link_socket);
+ socket_reset_listen_persistent (m->top.c2.link_socket);
+ mi = multi_create_instance_tcp (m);
+ if (mi)
+ multi_tcp_action (m, mi, TA_INITIAL, false);
+ }
+ /* signal received? */
+ else if (e->arg == MTCP_SIG)
+ {
+ get_signal (&m->top.sig->signal_received);
+ }
+ }
+ if (IS_SIG (&m->top))
+ break;
+ }
+ mtcp->n_esr = 0;
+
+ /*
+ * Process queued mbuf packets destined for TCP socket
+ */
+ {
+ struct multi_instance *mi;
+ while (!IS_SIG (&m->top) && (mi = mbuf_peek (m->mbuf)) != NULL)
+ {
+ multi_tcp_action (m, mi, TA_SOCKET_WRITE, true);
+ }
+ }
+}
+
+/*
+ * 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, MC_SINGLE_THREADED);
+
+ /* initialize our cloned top object */
+ multi_top_init (&multi, top, true);
+
+ /* initialize management interface */
+ init_management_callback_multi (&multi);
+
+ /* finished with initialization */
+ initialization_sequence_completed (top, ISC_SERVER); /* --mode server --proto tcp-server */
+
+ /* 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_tcp_wait (&multi.top, multi.mtcp);
+ 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_tcp_process_io (&multi);
+ MULTI_CHECK_SIG (&multi);
+ }
+ else if (status == 0)
+ {
+ multi_tcp_action (&multi, NULL, TA_TIMEOUT, false);
+ }
+
+ perf_pop ();
+ }
+
+ /* shut down management interface */
+ uninit_management_callback_multi (&multi);
+
+ /* 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);
+}
+
+#endif
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