diff options
Diffstat (limited to 'src/openvpn/mtcp.c')
| -rw-r--r-- | src/openvpn/mtcp.c | 721 |
1 files changed, 721 insertions, 0 deletions
diff --git a/src/openvpn/mtcp.c b/src/openvpn/mtcp.c new file mode 100644 index 0000000..662cb9a --- /dev/null +++ b/src/openvpn/mtcp.c @@ -0,0 +1,721 @@ +/* + * 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); + + 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; + } + +#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); + ASSERT (mi->context.c2.link_socket->info.lsa->actual.dest.addr.sa.sa_family == AF_INET + || mi->context.c2.link_socket->info.lsa->actual.dest.addr.sa.sa_family == AF_INET6 + ); + 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)) /* 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 |