genode/repos/os/include/net/ipv4.h
2015-03-13 12:17:23 +01:00

174 lines
4.8 KiB
C++

/*
* \brief Internet protocol version 4.
* \author Stefan Kalkowski
* \date 2010-08-19
*/
/*
* Copyright (C) 2010-2013 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _IPV4_H_
#define _IPV4_H_
/* Genode */
#include <base/exception.h>
#include <util/string.h>
#include <util/endian.h>
#include <net/netaddress.h>
namespace Net { class Ipv4_packet; }
/**
* Data layout of this class conforms to an IPv4 packet (RFC 791)
*
* IPv4-header-format:
*
* ----------------------------------------------------------------
* | 0-3 | 4-7 | 8-11 | 12-15 | 16-18 | 19-23 | 24-27 | 28-31 |
* ----------------------------------------------------------------
* | version | IHL | service-type | total-length |
* ----------------------------------------------------------------
* | identifikation | flags | fragment-offset |
* ----------------------------------------------------------------
* | ttl | protocol | header-checksum |
* ----------------------------------------------------------------
* | source-ip-address |
* ----------------------------------------------------------------
* | destination-ip-address |
* ----------------------------------------------------------------
* | options ... |
* ----------------------------------------------------------------
*/
class Net::Ipv4_packet
{
public:
enum Size {
ADDR_LEN = 4, /* Ip address length in bytes */
};
typedef Network_address<ADDR_LEN> Ipv4_address;
static const Ipv4_address CURRENT; /* current network */
static const Ipv4_address BROADCAST; /* broadcast address */
static Ipv4_address ip_from_string(const char *ip);
private:
/************************
** IPv4 header fields **
************************/
unsigned _version : 4;
unsigned _header_length : 4;
Genode::uint8_t _diff_service;
Genode::uint16_t _total_length;
Genode::uint16_t _identification;
unsigned _flags : 3;
unsigned _fragment_offset : 13;
Genode::uint8_t _time_to_live;
Genode::uint8_t _protocol;
Genode::uint16_t _header_checksum;
Genode::uint8_t _src_addr[ADDR_LEN];
Genode::uint8_t _dst_addr[ADDR_LEN];
unsigned _data[0];
/**
* Bitmasks for differentiated services field.
*/
enum Differentiated_services {
PRECEDENCE = 0x7,
DELAY = 0x8,
THROUGHPUT = 0x10,
RELIABILITY = 0x20,
COST = 0x40
};
public:
enum Precedence {
NETWORK_CONTROL = 7,
INTERNETWORK_CONTROL = 6,
CRITIC_ECP = 5,
FLASH_OVERRIDE = 4,
FLASH = 3,
IMMEDIATE = 2,
PRIORITY = 1,
ROUTINE = 0
};
enum Flags {
NO_FRAGMENT = 0x2,
MORE_FRAGMENTS = 0x4
};
/**
* Exception used to indicate protocol violation.
*/
class No_ip_packet : Genode::Exception {};
/*****************
** Constructor **
*****************/
Ipv4_packet(Genode::size_t size) {
/* ip header needs to fit in */
if (size < sizeof(Ipv4_packet))
throw No_ip_packet();
}
/*******************************
** IPv4 field read-accessors **
*******************************/
Genode::size_t version() { return _version; }
Genode::size_t header_length() { return _header_length / 4; }
Genode::uint8_t precedence() { return _diff_service & PRECEDENCE; }
bool low_delay() { return _diff_service & DELAY; }
bool high_throughput() { return _diff_service & THROUGHPUT; }
bool high_reliability() { return _diff_service & RELIABILITY;}
bool minimize_monetary_cost() { return _diff_service & COST; }
Genode::uint16_t total_length() { return bswap(_total_length); }
Genode::uint16_t identification() { return bswap(_identification); }
bool no_fragmentation() { return _flags & NO_FRAGMENT; }
bool more_fragments() { return _flags & MORE_FRAGMENTS; }
Genode::size_t fragment_offset() { return _fragment_offset; }
Genode::uint8_t time_to_live() { return _time_to_live; }
Genode::uint8_t protocol() { return _protocol; }
Genode::uint16_t checksum() { return bswap(_header_checksum); }
Ipv4_address dst() { return Ipv4_address(&_dst_addr); }
Ipv4_address src() { return Ipv4_address(&_src_addr); }
void *data() { return &_data; }
/***************
** Operators **
***************/
/**
* Placement new.
*/
void * operator new(Genode::size_t size, void* addr) {
return addr; }
} __attribute__((packed));
#endif /* _IPV4_H_ */