1 //
2 // Copyright (C) 2015 The Android Open Source Project
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 //      http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16 
17 #ifndef DHCP_CLIENT_DHCPV4_H_
18 #define DHCP_CLIENT_DHCPV4_H_
19 
20 #include <random>
21 #include <string>
22 
23 #include <base/macros.h>
24 #include <base/strings/stringprintf.h>
25 #include <shill/net/byte_string.h>
26 #include <shill/net/io_handler_factory_container.h>
27 #include <shill/net/sockets.h>
28 
29 #include "dhcp_client/dhcp.h"
30 #include "dhcp_client/dhcp_message.h"
31 #include "dhcp_client/event_dispatcher_interface.h"
32 
33 namespace dhcp_client {
34 
35 class DHCPV4 : public DHCP {
36  public:
37   DHCPV4(const std::string& interface_name,
38          const shill::ByteString& hardware_address,
39          unsigned int interface_index,
40          const std::string& network_id,
41          bool request_hostname,
42          bool arp_gateway,
43          bool unicast_arp,
44          EventDispatcherInterface* event_dispatcher);
45 
46   virtual ~DHCPV4();
47 
48   bool Start();
49   void Stop();
50 
51  private:
52   bool CreateRawSocket();
53   bool MakeRawPacket(const DHCPMessage& message, shill::ByteString* buffer);
54   void OnReadError(const std::string& error_msg);
55   void ParseRawPacket(shill::InputData* data);
56   bool SendRawPacket(const shill::ByteString& buffer);
57   // Validate the IP and UDP header and return the total headers length.
58   // Return -1 if any header is invalid.
59   int ValidatePacketHeader(const unsigned char* buffer, size_t len);
60 
61   void HandleOffer(const DHCPMessage& msg);
62   void HandleAck(const DHCPMessage& msg);
63   void HandleNak(const DHCPMessage& msg);
64 
65   // Interface parameters.
66   std::string interface_name_;
67   shill::ByteString hardware_address_;
68   unsigned int interface_index_;
69 
70   // Unique network/connection identifier,
71   // lease will persist to storage if this identifier is specified.
72   std::string network_id_;
73 
74   // DHCP IPv4 configurations:
75   // Request hostname from server.
76   bool request_hostname_;
77   // ARP for default gateway.
78   bool arp_gateway_;
79   // Enable unicast ARP on renew.
80   bool unicast_arp_;
81 
82   EventDispatcherInterface* event_dispatcher_;
83   shill::IOHandlerFactory *io_handler_factory_;
84   std::unique_ptr<shill::IOHandler> input_handler_;
85 
86   // DHCP state variables.
87   State state_;
88   uint32_t server_identifier_;
89   uint32_t transaction_id_;
90   uint32_t from_;
91   uint32_t to_;
92 
93   // Socket used for sending and receiving DHCP messages.
94   int socket_;
95   // Helper class with wrapped socket relavent functions.
96   std::unique_ptr<shill::Sockets> sockets_;
97 
98   std::default_random_engine random_engine_;
99 
100   DISALLOW_COPY_AND_ASSIGN(DHCPV4);
101 };
102 
103 }  // namespace dhcp_client
104 
105 #endif  // DHCP_CLIENT_DHCPV4_H_
106