Peter Qiu | bf8e36c | 2014-12-03 22:59:45 -0800 | [diff] [blame^] | 1 | // Copyright 2014 The Chromium OS Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "apmanager/dhcp_server.h" |
| 6 | |
| 7 | #include <net/if.h> |
| 8 | #include <signal.h> |
| 9 | |
| 10 | #include <base/files/file_util.h> |
| 11 | #include <base/strings/stringprintf.h> |
| 12 | |
| 13 | using std::string; |
| 14 | |
| 15 | namespace apmanager { |
| 16 | |
| 17 | // static. |
| 18 | const char DHCPServer::kDnsmasqPath[] = "/usr/sbin/dnsmasq"; |
| 19 | const char DHCPServer::kDnsmasqConfigFilePathFormat[] = "/tmp/dhcpd-%d.conf"; |
| 20 | const char DHCPServer::kDHCPLeasesFilePathFormat[] = "/tmp/dhcpd-%d.leases"; |
| 21 | const char DHCPServer::kServerAddressFormat[] = "192.168.%d.254"; |
| 22 | const char DHCPServer::kAddressRangeLowFormat[] = "192.168.%d.1"; |
| 23 | const char DHCPServer::kAddressRangeHighFormat[] = "192.168.%d.128"; |
| 24 | const int DHCPServer::kServerAddressPrefix = 24; |
| 25 | const int DHCPServer::kTerminationTimeoutSeconds = 2; |
| 26 | |
| 27 | DHCPServer::DHCPServer(uint16_t server_address_index, |
| 28 | const string& interface_name) |
| 29 | : server_address_index_(server_address_index), |
| 30 | interface_name_(interface_name), |
| 31 | server_address_(shill::IPAddress::kFamilyIPv4), |
| 32 | rtnl_handler_(shill::RTNLHandler::GetInstance()) {} |
| 33 | |
| 34 | DHCPServer::~DHCPServer() { |
| 35 | if (dnsmasq_process_) { |
| 36 | // The destructor of the Process will send a SIGKILL signal if it is not |
| 37 | // already terminated. |
| 38 | dnsmasq_process_->Kill(SIGTERM, kTerminationTimeoutSeconds); |
| 39 | dnsmasq_process_.reset(); |
| 40 | rtnl_handler_->RemoveInterfaceAddress( |
| 41 | rtnl_handler_->GetInterfaceIndex(interface_name_), server_address_); |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | bool DHCPServer::Start() { |
| 46 | if (dnsmasq_process_) { |
| 47 | LOG(ERROR) << "DHCP Server already running"; |
| 48 | return false; |
| 49 | } |
| 50 | |
| 51 | // Generate dnsmasq config file. |
| 52 | string config_str = GenerateConfigFile(); |
| 53 | base::FilePath file_path(base::StringPrintf(kDnsmasqConfigFilePathFormat, |
| 54 | server_address_index_)); |
| 55 | if (base::WriteFile(file_path, config_str.c_str(), config_str.size()) == -1) { |
| 56 | LOG(ERROR) << "Failed to write configuration to a file"; |
| 57 | return false; |
| 58 | } |
| 59 | |
| 60 | // Setup local server address and bring up the interface in case it is down. |
| 61 | server_address_.SetAddressFromString( |
| 62 | base::StringPrintf(kServerAddressFormat, server_address_index_)); |
| 63 | server_address_.set_prefix(kServerAddressPrefix); |
| 64 | int interface_index = rtnl_handler_->GetInterfaceIndex(interface_name_); |
| 65 | rtnl_handler_->AddInterfaceAddress( |
| 66 | interface_index, |
| 67 | server_address_, |
| 68 | server_address_.GetDefaultBroadcast(), |
| 69 | shill::IPAddress(shill::IPAddress::kFamilyIPv4)); |
| 70 | rtnl_handler_->SetInterfaceFlags(interface_index, IFF_UP, IFF_UP); |
| 71 | |
| 72 | // TODO(zqiu): use ProcessFactory for better unit testing. |
| 73 | // Start a dnsmasq process. |
| 74 | dnsmasq_process_.reset(new chromeos::ProcessImpl()); |
| 75 | dnsmasq_process_->AddArg(kDnsmasqPath); |
| 76 | dnsmasq_process_->AddArg(base::StringPrintf("--conf-file=%s", |
| 77 | file_path.value().c_str())); |
| 78 | if (!dnsmasq_process_->Start()) { |
| 79 | rtnl_handler_->RemoveInterfaceAddress(interface_index, server_address_); |
| 80 | dnsmasq_process_.reset(); |
| 81 | LOG(ERROR) << "Failed to start dnsmasq process"; |
| 82 | return false; |
| 83 | } |
| 84 | |
| 85 | return true; |
| 86 | } |
| 87 | |
| 88 | string DHCPServer::GenerateConfigFile() { |
| 89 | string server_address = base::StringPrintf(kServerAddressFormat, |
| 90 | server_address_index_); |
| 91 | string address_low = base::StringPrintf(kAddressRangeLowFormat, |
| 92 | server_address_index_); |
| 93 | string address_high = base::StringPrintf(kAddressRangeHighFormat, |
| 94 | server_address_index_); |
| 95 | string lease_file_path = base::StringPrintf(kDHCPLeasesFilePathFormat, |
| 96 | server_address_index_); |
| 97 | string config; |
| 98 | config += "port=0\n"; |
| 99 | config += "bind-interfaces\n"; |
| 100 | config += "log-dhcp\n"; |
| 101 | base::StringAppendF( |
| 102 | &config, "dhcp-range=%s,%s\n", address_low.c_str(), address_high.c_str()); |
| 103 | base::StringAppendF(&config, "interface=%s\n", interface_name_.c_str()); |
| 104 | base::StringAppendF(&config, "dhcp-leasefile=%s\n", lease_file_path.c_str()); |
| 105 | return config; |
| 106 | } |
| 107 | |
| 108 | } // namespace apmanager |