/*
* 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) 2002-2018 OpenVPN 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; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.h"
#endif
#include "syshead.h"
#include "forward.h"
#include "helper.h"
#include "pool.h"
#include "push.h"
#include "memdbg.h"
#if P2MP_SERVER
static const char *
print_netmask(int netbits, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(128, gc);
const in_addr_t netmask = netbits_to_netmask(netbits);
buf_printf(&out, "%s (/%d)", print_in_addr_t(netmask, 0, gc), netbits);
return BSTR(&out);
}
static const char *
print_opt_route_gateway(const in_addr_t route_gateway, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(128, gc);
ASSERT(route_gateway);
buf_printf(&out, "route-gateway %s", print_in_addr_t(route_gateway, 0, gc));
return BSTR(&out);
}
static const char *
print_opt_route_gateway_dhcp(struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(32, gc);
buf_printf(&out, "route-gateway dhcp");
return BSTR(&out);
}
static const char *
print_opt_route(const in_addr_t network, const in_addr_t netmask, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(128, gc);
ASSERT(network);
if (netmask)
{
buf_printf(&out, "route %s %s",
print_in_addr_t(network, 0, gc),
print_in_addr_t(netmask, 0, gc));
}
else
{
buf_printf(&out, "route %s",
print_in_addr_t(network, 0, gc));
}
return BSTR(&out);
}
static const char *
print_opt_topology(const int topology, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(128, gc);
buf_printf(&out, "topology %s", print_topology(topology));
return BSTR(&out);
}
static const char *
print_str_int(const char *str, const int i, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(128, gc);
buf_printf(&out, "%s %d", str, i);
return BSTR(&out);
}
static const char *
print_str(const char *str, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(128, gc);
buf_printf(&out, "%s", str);
return BSTR(&out);
}
static void
helper_add_route(const in_addr_t network, const in_addr_t netmask, struct options *o)
{
rol_check_alloc(o);
add_route_to_option_list(o->routes,
print_in_addr_t(network, 0, &o->gc),
print_in_addr_t(netmask, 0, &o->gc),
NULL,
NULL);
}
static void
verify_common_subnet(const char *opt, const in_addr_t a, const in_addr_t b, const in_addr_t subnet)
{
struct gc_arena gc = gc_new();
if ((a & subnet) != (b & subnet))
{
msg(M_USAGE, "%s IP addresses %s and %s are not in the same %s subnet",
opt,
print_in_addr_t(a, 0, &gc),
print_in_addr_t(b, 0, &gc),
print_in_addr_t(subnet, 0, &gc));
}
gc_free(&gc);
}
#endif /* if P2MP_SERVER */
/*
* Process server, server-bridge, and client helper
* directives after the parameters themselves have been
* parsed and placed in struct options.
*/
void
helper_client_server(struct options *o)
{
struct gc_arena gc = gc_new();
#if P2MP
#if P2MP_SERVER
/*
* Get tun/tap/null device type
*/
const int dev = dev_type_enum(o->dev, o->dev_type);
const int topology = o->topology;
/*
*
* HELPER DIRECTIVE for IPv6
*
* server-ipv6 2001:db8::/64
*
* EXPANDS TO:
*
* tun-ipv6
* push "tun-ipv6"
* ifconfig-ipv6 2001:db8::1 2001:db8::2
* if !nopool:
* ifconfig-ipv6-pool 2001:db8::1000/64
*
*/
if (o->server_ipv6_defined)
{
if (!o->server_defined)
{
msg(M_USAGE, "--server-ipv6 must be used together with --server");
}
if (o->server_flags & SF_NOPOOL)
{
msg( M_USAGE, "--server-ipv6 is incompatible with 'nopool' option" );
}
if (o->ifconfig_ipv6_pool_defined)
{
msg( M_USAGE, "--server-ipv6 already defines an ifconfig-ipv6-pool, so you can't also specify --ifconfig-pool explicitly");
}
/* local ifconfig is "base address + 1" and "+2" */
o->ifconfig_ipv6_local =
print_in6_addr( add_in6_addr( o->server_network_ipv6, 1), 0, &o->gc );
o->ifconfig_ipv6_remote =
print_in6_addr( add_in6_addr( o->server_network_ipv6, 2), 0, &o->gc );
o->ifconfig_ipv6_netbits = o->server_netbits_ipv6;
/* pool starts at "base address + 0x1000" - leave enough room */
ASSERT( o->server_netbits_ipv6 <= 112 ); /* want 16 bits */
o->ifconfig_ipv6_pool_defined = true;
o->ifconfig_ipv6_pool_base =
add_in6_addr( o->server_network_ipv6, 0x1000 );
o->ifconfig_ipv6_pool_netbits = o->server_netbits_ipv6;
push_option( o, "tun-ipv6", M_USAGE );
}
/*
*
* HELPER DIRECTIVE:
*
* server 10.8.0.0 255.255.255.0
*
* EXPANDS TO:
*
* mode server
* tls-server
* push "topology [topology]"
*
* if tun AND (topology == net30 OR topology == p2p):
* ifconfig 10.8.0.1 10.8.0.2
* if !nopool:
* ifconfig-pool 10.8.0.4 10.8.0.251
* route 10.8.0.0 255.255.255.0
* if client-to-client:
* push "route 10.8.0.0 255.255.255.0"
* else if topology == net30:
* push "route 10.8.0.1"
*
* if tap OR (tun AND topology == subnet):
* ifconfig 10.8.0.1 255.255.255.0
* if !nopool:
* ifconfig-pool 10.8.0.2 10.8.0.253 255.255.255.0
* push "route-gateway 10.8.0.1"
* if route-gateway unset:
* route-gateway 10.8.0.2
*/
if (o->server_defined)
{
int netbits = -2;
bool status = false;
if (o->client)
{
msg(M_USAGE, "--server and --client cannot be used together");
}
if (o->server_bridge_defined || o->server_bridge_proxy_dhcp)
{
msg(M_USAGE, "--server and --server-bridge cannot be used together");
}
if (o->shared_secret_file)
{
msg(M_USAGE, "--server and --secret cannot be used together (you must use SSL/TLS keys)");
}
if (!(o->server_flags & SF_NOPOOL) && o->ifconfig_pool_defined)
{
msg(M_USAGE, "--server already defines an ifconfig-pool, so you can't also specify --ifconfig-pool explicitly");
}
if (!(dev == DEV_TYPE_TAP || dev == DEV_TYPE_TUN))
{
msg(M_USAGE, "--server directive only makes sense with --dev tun or --dev tap");
}
status = netmask_to_netbits(o->server_network, o->server_netmask, &netbits);
if (!status)
{
msg(M_USAGE, "--server directive network/netmask combination is invalid");
}
if (netbits < 0)
{
msg(M_USAGE, "--server directive netmask is invalid");
}
if (netbits < IFCONFIG_POOL_MIN_NETBITS)
{
msg(M_USAGE, "--server directive netmask allows for too many host addresses (subnet must be %s or higher)",
print_netmask(IFCONFIG_POOL_MIN_NETBITS, &gc));
}
if (dev == DEV_TYPE_TUN)
{
int pool_end_reserve = 4;
if (netbits > 29)
{
msg(M_USAGE, "--server directive when used with --dev tun must define a subnet of %s or lower",
print_netmask(29, &gc));
}
if (netbits == 29)
{
pool_end_reserve = 0;
}
o->mode = MODE_SERVER;
o->tls_server = true;
if (topology == TOP_NET30 || topology == TOP_P2P)
{
o->ifconfig_local = print_in_addr_t(o->server_network + 1, 0, &o->gc);
o->ifconfig_remote_netmask = print_in_addr_t(o->server_network + 2, 0, &o->gc);
if (!(o->server_flags & SF_NOPOOL))
{
o->ifconfig_pool_defined = true;
o->ifconfig_pool_start = o->server_network + 4;
o->ifconfig_pool_end = (o->server_network | ~o->server_netmask) - pool_end_reserve;
ifconfig_pool_verify_range(M_USAGE, o->ifconfig_pool_start, o->ifconfig_pool_end);
}
helper_add_route(o->server_network, o->server_netmask, o);
if (o->enable_c2c)
{
push_option(o, print_opt_route(o->server_network, o->server_netmask, &o->gc), M_USAGE);
}
else if (topology == TOP_NET30)
{
push_option(o, print_opt_route(o->server_network + 1, 0, &o->gc), M_USAGE);
}
}
else if (topology == TOP_SUBNET)
{
o->ifconfig_local = print_in_addr_t(o->server_network + 1, 0, &o->gc);
o->ifconfig_remote_netmask = print_in_addr_t(o->server_netmask, 0, &o->gc);
if (!(o->server_flags & SF_NOPOOL))
{
o->ifconfig_pool_defined = true;
o->ifconfig_pool_start = o->server_network + 2;
o->ifconfig_pool_end = (o->server_network | ~o->server_netmask) - 2;
ifconfig_pool_verify_range(M_USAGE, o->ifconfig_pool_start, o->ifconfig_pool_end);
}
o->ifconfig_pool_netmask = o->server_netmask;
push_option(o, print_opt_route_gateway(o->server_network + 1, &o->gc), M_USAGE);
if (!o->route_default_gateway)
{
o->route_default_gateway = print_in_addr_t(o->server_network + 2, 0, &o->gc);
}
}
else
{
ASSERT(0);
}
push_option(o, print_opt_topology(topology, &o->gc), M_USAGE);
}
else if (dev == DEV_TYPE_TAP)
{
if (netbits > 30)
{
msg(M_USAGE, "--server directive when used with --dev tap must define a subnet of %s or lower",
print_netmask(30, &gc));
}
o->mode = MODE_SERVER;
o->tls_server = true;
o->ifconfig_local = print_in_addr_t(o->server_network + 1, 0, &o->gc);
o->ifconfig_remote_netmask = print_in_addr_t(o->server_netmask, 0, &o->gc);
if (!(o->server_flags & SF_NOPOOL))
{
o->ifconfig_pool_defined = true;
o->ifconfig_pool_start = o->server_network + 2;
o->ifconfig_pool_end = (o->server_network | ~o->server_netmask) - 1;
ifconfig_pool_verify_range(M_USAGE, o->ifconfig_pool_start, o->ifconfig_pool_end);
}
o->ifconfig_pool_netmask = o->server_netmask;
push_option(o, print_opt_route_gateway(o->server_network + 1, &o->gc), M_USAGE);
}
else
{
ASSERT(0);
}
/* set push-ifconfig-constraint directive */
if ((dev == DEV_TYPE_TAP || topology == TOP_SUBNET))
{
o->push_ifconfig_constraint_defined = true;
o->push_ifconfig_constraint_network = o->server_network;
o->push_ifconfig_constraint_netmask = o->server_netmask;
}
}
/*
* HELPER DIRECTIVE:
*
* server-bridge 10.8.0.4 255.255.255.0 10.8.0.128 10.8.0.254
*
* EXPANDS TO:
*
* mode server
* tls-server
*
* ifconfig-pool 10.8.0.128 10.8.0.254 255.255.255.0
* push "route-gateway 10.8.0.4"
*
* OR
*
* server-bridge
*
* EXPANDS TO:
*
* mode server
* tls-server
*
* if !nogw:
* push "route-gateway dhcp"
*/
else if (o->server_bridge_defined | o->server_bridge_proxy_dhcp)
{
if (o->client)
{
msg(M_USAGE, "--server-bridge and --client cannot be used together");
}
if (!(o->server_flags & SF_NOPOOL) && o->ifconfig_pool_defined)
{
msg(M_USAGE, "--server-bridge already defines an ifconfig-pool, so you can't also specify --ifconfig-pool explicitly");
}
if (o->shared_secret_file)
{
msg(M_USAGE, "--server-bridge and --secret cannot be used together (you must use SSL/TLS keys)");
}
if (dev != DEV_TYPE_TAP)
{
msg(M_USAGE, "--server-bridge directive only makes sense with --dev tap");
}
if (o->server_bridge_defined)
{
verify_common_subnet("--server-bridge", o->server_bridge_ip, o->server_bridge_pool_start, o->server_bridge_netmask);
verify_common_subnet("--server-bridge", o->server_bridge_pool_start, o->server_bridge_pool_end, o->server_bridge_netmask);
verify_common_subnet("--server-bridge", o->server_bridge_ip, o->server_bridge_pool_end, o->server_bridge_netmask);
}
o->mode = MODE_SERVER;
o->tls_server = true;
if (o->server_bridge_defined)
{
o->ifconfig_pool_defined = true;
o->ifconfig_pool_start = o->server_bridge_pool_start;
o->ifconfig_pool_end = o->server_bridge_pool_end;
ifconfig_pool_verify_range(M_USAGE, o->ifconfig_pool_start, o->ifconfig_pool_end);
o->ifconfig_pool_netmask = o->server_bridge_netmask;
push_option(o, print_opt_route_gateway(o->server_bridge_ip, &o->gc), M_USAGE);
}
else if (o->server_bridge_proxy_dhcp && !(o->server_flags & SF_NO_PUSH_ROUTE_GATEWAY))
{
push_option(o, print_opt_route_gateway_dhcp(&o->gc), M_USAGE);
}
}
else
#endif /* P2MP_SERVER */
/*
* HELPER DIRECTIVE:
*
* client
*
* EXPANDS TO:
*
* pull
* tls-client
*/
if (o->client)
{
if (o->key_method != 2)
{
msg(M_USAGE, "--client requires --key-method 2");
}
o->pull = true;
o->tls_client = true;
}
#endif /* P2MP */
gc_free(&gc);
}
/*
*
* HELPER DIRECTIVE:
*
* keepalive 10 60
*
* EXPANDS TO:
*
* if mode server:
* ping 10
* ping-restart 120
* push "ping 10"
* push "ping-restart 60"
* else
* ping 10
* ping-restart 60
*/
void
helper_keepalive(struct options *o)
{
if (o->keepalive_ping || o->keepalive_timeout)
{
/*
* Sanity checks.
*/
if (o->keepalive_ping <= 0 || o->keepalive_timeout <= 0)
{
msg(M_USAGE, "--keepalive parameters must be > 0");
}
if (o->keepalive_ping * 2 > o->keepalive_timeout)
{
msg(M_USAGE, "the second parameter to --keepalive (restart timeout=%d) must be at least twice the value of the first parameter (ping interval=%d). A ratio of 1:5 or 1:6 would be even better. Recommended setting is --keepalive 10 60.",
o->keepalive_timeout,
o->keepalive_ping);
}
if (o->ping_send_timeout || o->ping_rec_timeout)
{
msg(M_USAGE, "--keepalive conflicts with --ping, --ping-exit, or --ping-restart. If you use --keepalive, you don't need any of the other --ping directives.");
}
/*
* Expand.
*/
if (o->mode == MODE_POINT_TO_POINT)
{
o->ping_rec_timeout_action = PING_RESTART;
o->ping_send_timeout = o->keepalive_ping;
o->ping_rec_timeout = o->keepalive_timeout;
}
#if P2MP_SERVER
else if (o->mode == MODE_SERVER)
{
o->ping_rec_timeout_action = PING_RESTART;
o->ping_send_timeout = o->keepalive_ping;
o->ping_rec_timeout = o->keepalive_timeout * 2;
push_option(o, print_str_int("ping", o->keepalive_ping, &o->gc), M_USAGE);
push_option(o, print_str_int("ping-restart", o->keepalive_timeout, &o->gc), M_USAGE);
}
#endif
else
{
ASSERT(0);
}
}
}
/*
*
* HELPER DIRECTIVE:
*
* tcp-nodelay
*
* EXPANDS TO:
*
* if mode server:
* socket-flags TCP_NODELAY
* push "socket-flags TCP_NODELAY"
*/
void
helper_tcp_nodelay(struct options *o)
{
#if P2MP_SERVER
if (o->server_flags & SF_TCP_NODELAY_HELPER)
{
if (o->mode == MODE_SERVER)
{
o->sockflags |= SF_TCP_NODELAY;
push_option(o, print_str("socket-flags TCP_NODELAY", &o->gc), M_USAGE);
}
else
{
o->sockflags |= SF_TCP_NODELAY;
}
}
#endif
}