genode/repos/os/include/net/udp.h
Martin Stein 980f3e9c5c net: use Size_guard for packet-data accessors
Instead of handing over the maximum available size to the packet data
accessors, hand over a size guard that keeps track of the packets
boundaries.

This commit also moves the size-guard utilitiy header of Ping and NIC
Router to the include/net directory making it a part of the net library.
It applies the new approach to all net-lib users in the basic repositories.

Ping looses its configurability regarding the ICMP data size as this would
require an additional method in the size guard which would be used only by
Ping.

The size guard was also re-worked to fit the fact that a packet can
bring a tail as well as a header (Ethernet).

Issue #2788
2018-05-30 13:36:11 +02:00

105 lines
2.5 KiB
C++

/*
* \brief User datagram protocol.
* \author Stefan Kalkowski
* \date 2010-08-19
*/
/*
* Copyright (C) 2010-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _UDP_H_
#define _UDP_H_
/* Genode */
#include <base/exception.h>
#include <base/stdint.h>
#include <net/port.h>
#include <util/endian.h>
#include <net/ethernet.h>
#include <net/ipv4.h>
namespace Net { class Udp_packet; }
/**
* Data layout of this class conforms to an UDP packet (RFC 768)
*
* UDP-header-format:
*
* -----------------------------------------------------------------------
* | source-port | destination-port | length | checksum |
* | 2 bytes | 2 bytes | 2 bytes | 2 bytes |
* -----------------------------------------------------------------------
*/
class Net::Udp_packet
{
private:
/***********************
** UDP header fields **
***********************/
Genode::uint16_t _src_port;
Genode::uint16_t _dst_port;
Genode::uint16_t _length;
Genode::uint16_t _checksum;
unsigned _data[0];
public:
template <typename T>
T const &data(Size_guard &size_guard) const
{
size_guard.consume_head(sizeof(T));
return *(T const *)(_data);
}
template <typename T>
T &data(Size_guard &size_guard)
{
size_guard.consume_head(sizeof(T));
return *(T *)(_data);
}
template <typename T, typename SIZE_GUARD>
T &construct_at_data(SIZE_GUARD &size_guard)
{
size_guard.consume_head(sizeof(T));
return *Genode::construct_at<T>(_data);
}
void update_checksum(Ipv4_address ip_src,
Ipv4_address ip_dst);
bool checksum_error(Ipv4_address ip_src,
Ipv4_address ip_dst) const;
/***************
** Accessors **
***************/
Port src_port() const { return Port(host_to_big_endian(_src_port)); }
Port dst_port() const { return Port(host_to_big_endian(_dst_port)); }
Genode::uint16_t length() const { return host_to_big_endian(_length); }
Genode::uint16_t checksum() const { return host_to_big_endian(_checksum); }
void length(Genode::uint16_t v) { _length = host_to_big_endian(v); }
void src_port(Port p) { _src_port = host_to_big_endian(p.value); }
void dst_port(Port p) { _dst_port = host_to_big_endian(p.value); }
/*********
** log **
*********/
void print(Genode::Output &output) const;
} __attribute__((packed));
#endif /* _UDP_H_ */