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C++

// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012-2017 OpenVPN Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License Version 3
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program in the COPYING file.
// If not, see <http://www.gnu.org/licenses/>.
// DNS utilities for Mac OS X.
#ifndef OPENVPN_TUN_MAC_MACDNS_H
#define OPENVPN_TUN_MAC_MACDNS_H
#include <string>
#include <sstream>
#include <memory>
#include <openvpn/common/size.hpp>
#include <openvpn/common/exception.hpp>
#include <openvpn/common/string.hpp>
#include <openvpn/common/process.hpp>
#include <openvpn/apple/macver.hpp>
#include <openvpn/apple/scdynstore.hpp>
#include <openvpn/apple/cf/cfhelper.hpp>
#include <openvpn/tun/builder/capture.hpp>
#include <openvpn/tun/mac/dsdict.hpp>
namespace openvpn {
class MacDNS : public RC<thread_unsafe_refcount>
{
class Info;
public:
typedef RCPtr<MacDNS> Ptr;
OPENVPN_EXCEPTION(macdns_error);
class Config : public RC<thread_safe_refcount>
{
public:
typedef RCPtr<Config> Ptr;
Config()
{
}
Config(const TunBuilderCapture& settings)
: dns_servers(get_dns_servers(settings)),
search_domains(get_search_domains(settings)),
adapter_domain_suffix(settings.adapter_domain_suffix)
{
// We redirect DNS if either of the following is true:
// 1. redirect-gateway (IPv4) is pushed, or
// 2. DNS servers are pushed but no search domains are pushed
redirect_dns = settings.reroute_gw.ipv4 || (CF::array_len(dns_servers) && !CF::array_len(search_domains));
}
std::string to_string() const
{
std::ostringstream os;
os << "RD=" << redirect_dns;
os << " SO=" << search_order;
os << " DNS=" << CF::array_to_string(dns_servers);
os << " DOM=" << CF::array_to_string(search_domains);
os << " ADS=" << adapter_domain_suffix;
return os.str();
}
bool redirect_dns = false;
int search_order = 5000;
CF::Array dns_servers;
CF::Array search_domains;
std::string adapter_domain_suffix;
private:
static CF::Array get_dns_servers(const TunBuilderCapture& settings)
{
CF::MutableArray ret(CF::mutable_array());
for (std::vector<TunBuilderCapture::DNSServer>::const_iterator i = settings.dns_servers.begin();
i != settings.dns_servers.end(); ++i)
{
const TunBuilderCapture::DNSServer& ds = *i;
CF::array_append_str(ret, ds.address);
}
return CF::const_array(ret);
}
static CF::Array get_search_domains(const TunBuilderCapture& settings)
{
CF::MutableArray ret(CF::mutable_array());
for (std::vector<TunBuilderCapture::SearchDomain>::const_iterator i = settings.search_domains.begin();
i != settings.search_domains.end(); ++i)
{
const TunBuilderCapture::SearchDomain& sd = *i;
CF::array_append_str(ret, sd.domain);
}
return CF::const_array(ret);
}
};
MacDNS(const std::string& sname_arg)
: sname(sname_arg)
{
}
void flush_cache()
{
const int v = ver.major();
if (v < Mac::Version::OSX_10_6)
OPENVPN_LOG("MacDNS: Error: No support for Mac OS X versions earlier than 10.6");
if (v == Mac::Version::OSX_10_6 || v >= Mac::Version::OSX_10_9)
{
Argv args;
args.push_back("/usr/bin/dscacheutil");
args.push_back("-flushcache");
OPENVPN_LOG(args.to_string());
system_cmd(args);
}
if (v >= Mac::Version::OSX_10_7)
{
Argv args;
args.push_back("/usr/bin/killall");
args.push_back("-HUP");
args.push_back("mDNSResponder");
OPENVPN_LOG(args.to_string());
system_cmd(args);
}
}
bool signal_network_reconfiguration()
{
return DSDict::signal_network_reconfiguration(sname);
}
bool setdns(const Config& config)
{
bool mod = false;
try {
CF::DynamicStore sc = ds_create();
Info::Ptr info(new Info(sc, sname));
// cleanup settings applied to previous interface
interface_change_cleanup(info.get());
if (config.redirect_dns)
{
// redirect all DNS
info->dns.will_modify();
// set DNS servers
if (CF::array_len(config.dns_servers))
{
info->dns.backup_orig("ServerAddresses");
CF::dict_set_obj(info->dns.mod, "ServerAddresses", config.dns_servers());
}
// set search domains
info->dns.backup_orig("SearchDomains");
CF::MutableArray search_domains(CF::mutable_array());
// add adapter_domain_suffix to SearchDomains for domain autocompletion
if (config.adapter_domain_suffix.length() > 0)
CF::array_append_str(search_domains, config.adapter_domain_suffix);
if (CF::array_len(search_domains))
CF::dict_set_obj(info->dns.mod, "SearchDomains", search_domains());
// set search order
info->dns.backup_orig("SearchOrder");
CF::dict_set_int(info->dns.mod, "SearchOrder", config.search_order);
// push it
mod |= info->dns.push_to_store();
}
else
{
// split-DNS - resolve only specific domains
info->ovpn.mod_reset();
if (CF::array_len(config.dns_servers) && CF::array_len(config.search_domains))
{
// set DNS servers
CF::dict_set_obj(info->ovpn.mod, "ServerAddresses", config.dns_servers());
// DNS will be used only for those domains
CF::dict_set_obj(info->ovpn.mod, "SupplementalMatchDomains", config.search_domains());
// do not use those domains in autocompletion
CF::dict_set_int(info->ovpn.mod, "SupplementalMatchDomainsNoSearch", 1);
}
// in case of split-DNS macOS uses domain suffix of network adapter,
// not the one provided by VPN (which we put to SearchDomains)
// push it
mod |= info->ovpn.push_to_store();
}
if (mod)
{
// As a backup, save PrimaryService in private dict (if network goes down while
// we are set, we can lose info about PrimaryService in State:/Network/Global/IPv4
// and be unable to reset ourselves).
const CFTypeRef ps = CF::dict_get_obj(info->ipv4.dict, "PrimaryService");
if (ps)
{
info->info.mod_reset();
CF::dict_set_obj(info->info.mod, "PrimaryService", ps);
info->info.push_to_store();
}
}
prev = info;
if (mod)
OPENVPN_LOG("MacDNS: SETDNS " << ver.to_string() << std::endl << info->to_string());
}
catch (const std::exception& e)
{
OPENVPN_LOG("MacDNS: setdns exception: " << e.what());
}
return mod;
}
bool resetdns()
{
bool mod = false;
try {
CF::DynamicStore sc = ds_create();
Info::Ptr info(new Info(sc, sname));
// cleanup settings applied to previous interface
interface_change_cleanup(info.get());
// undo primary dns changes
mod |= reset_primary_dns(info.get());
// undo non-redirect-gateway changes
if (CF::dict_len(info->ovpn.dict))
mod |= info->ovpn.remove_from_store();
// remove private info dict
if (CF::dict_len(info->info.dict))
mod |= info->info.remove_from_store();
if (mod)
OPENVPN_LOG("MacDNS: RESETDNS " << ver.to_string() << std::endl << info->to_string());
}
catch (const std::exception& e)
{
OPENVPN_LOG("MacDNS: resetdns exception: " << e.what());
}
return mod;
}
std::string to_string() const
{
CF::DynamicStore sc = ds_create();
Info::Ptr info(new Info(sc, sname));
return info->to_string();
}
CF::Array dskey_array() const
{
CF::DynamicStore sc = ds_create();
Info::Ptr info(new Info(sc, sname));
CF::MutableArray ret(CF::mutable_array());
CF::array_append_str(ret, info->ipv4.dskey);
CF::array_append_str(ret, info->info.dskey);
CF::array_append_str(ret, info->ovpn.dskey);
CF::array_append_str(ret, info->dns.dskey);
return CF::const_array(ret);
}
private:
void interface_change_cleanup(Info* info)
{
if (info->interface_change(prev.get()))
{
reset_primary_dns(prev.get());
prev.reset();
}
}
bool reset_primary_dns(Info* info)
{
bool mod = false;
if (info)
{
#if 1
// Restore previous DNS settings.
// Recommended for production.
info->dns.will_modify();
info->dns.restore_orig();
mod |= info->dns.push_to_store();
#else
// Wipe DNS settings without restore.
// This can potentially wipe static IP/DNS settings.
info->dns.mod_reset();
mod |= info->dns.push_to_store();
#endif
}
return mod;
}
class Info : public RC<thread_unsafe_refcount>
{
public:
typedef RCPtr<Info> Ptr;
Info(CF::DynamicStore& sc, const std::string& sname)
: ipv4(sc, sname, "State:/Network/Global/IPv4"),
info(sc, sname, "State:/Network/Service/" + sname + "/Info"),
ovpn(sc, sname, "State:/Network/Service/" + sname + "/DNS"),
dns(sc, sname, primary_dns(ipv4.dict, info.dict))
{
}
std::string to_string() const
{
std::ostringstream os;
os << ipv4.to_string();
os << info.to_string();
os << ovpn.to_string();
os << dns.to_string();
return os.str();
}
bool interface_change(Info* other) const
{
return other && dns.dskey != other->dns.dskey;
}
DSDict ipv4;
DSDict info; // we may modify
DSDict ovpn; // we may modify
DSDict dns; // we may modify
private:
static std::string primary_dns(const CF::Dict& ipv4, const CF::Dict& info)
{
std::string serv = CF::dict_get_str(ipv4, "PrimaryService");
if (serv.empty())
serv = CF::dict_get_str(info, "PrimaryService");
if (serv.empty())
throw macdns_error("no primary service");
return "Setup:/Network/Service/" + serv + "/DNS";
}
};
CF::DynamicStore ds_create() const
{
return DSDict::ds_create(sname);
}
const std::string sname;
Mac::Version ver;
Info::Ptr prev;
};
}
#endif