1 /*
2  *  Hans - IP over ICMP
3  *  Copyright (C) 2009 Friedrich Schöller <hans@schoeller.se>
4  *
5  *  This program is free software: you can redistribute it and/or modify
6  *  it under the terms of the GNU General Public License as published by
7  *  the Free Software Foundation, either version 3 of the License, or
8  *  (at your option) any later version.
9  *
10  *  This program is distributed in the hope that it will be useful,
11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  *  GNU General Public License for more details.
14  *
15  *  You should have received a copy of the GNU General Public License
16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
17  *
18  */
19 
20 #ifndef ECHO_H
21 #define ECHO_H
22 
23 #include <string>
24 #include <stdint.h>
25 
26 class Echo
27 {
28 public:
29     Echo(int maxPayloadSize);
30     ~Echo();
31 
getFd()32     int getFd() { return fd; }
33 
34     void send(int payloadLength, uint32_t realIp, bool reply, uint16_t id, uint16_t seq);
35     int receive(uint32_t &realIp, bool &reply, uint16_t &id, uint16_t &seq);
36 
sendPayloadBuffer()37     char *sendPayloadBuffer() { return sendBuffer + headerSize(); }
receivePayloadBuffer()38     char *receivePayloadBuffer() { return receiveBuffer + headerSize(); }
39 
40     static int headerSize();
41 protected:
42     struct EchoHeader
43     {
44         uint8_t type;
45         uint8_t code;
46         uint16_t chksum;
47         uint16_t id;
48         uint16_t seq;
49     }; // size = 8
50 
51     uint16_t icmpChecksum(const char *data, int length);
52 
53     int fd;
54     int bufferSize;
55     char *sendBuffer, *receiveBuffer;
56 };
57 
58 #endif
59