/*
* 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) 2002-2010 OpenVPN Technologies, Inc. <sales@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
*/
#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_openvpn_sockaddr (&mi->real, &mi->context.c2.link_socket->info.lsa->actual.dest, 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