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299 lines
8.0 KiB
C++
299 lines
8.0 KiB
C++
/*
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* \brief Internet protocol version 4.
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* \author Stefan Kalkowski
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* \date 2010-08-19
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*/
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/*
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* Copyright (C) 2010-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _IPV4_H_
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#define _IPV4_H_
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/* Genode */
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#include <base/exception.h>
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#include <util/string.h>
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#include <util/token.h>
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#include <util/endian.h>
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#include <net/netaddress.h>
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namespace Genode { class Output; }
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namespace Net
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{
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enum { IPV4_ADDR_LEN = 4 };
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class Ipv4_address;
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class Ipv4_address_prefix;
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class Ipv4_packet;
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}
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struct Net::Ipv4_address : Network_address<IPV4_ADDR_LEN, '.', false>
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{
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Ipv4_address(Genode::uint8_t value = 0) : Network_address(value) { }
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Ipv4_address(void *src) : Network_address(src) { }
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bool valid() const { return *this != Ipv4_address(); }
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}
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__attribute__((packed));
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/**
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* Data layout of this class conforms to an IPv4 packet (RFC 791)
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*
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* IPv4-header-format:
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*
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* ----------------------------------------------------------------
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* | 0-3 | 4-7 | 8-11 | 12-15 | 16-18 | 19-23 | 24-27 | 28-31 |
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* ----------------------------------------------------------------
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* | version | IHL | service-type | total-length |
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* ----------------------------------------------------------------
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* | identifikation | flags | fragment-offset |
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* ----------------------------------------------------------------
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* | ttl | protocol | header-checksum |
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* ----------------------------------------------------------------
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* | source-ip-address |
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* ----------------------------------------------------------------
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* | destination-ip-address |
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* ----------------------------------------------------------------
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* | options ... |
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* ----------------------------------------------------------------
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*/
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class Net::Ipv4_packet
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{
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public:
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enum Size {
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ADDR_LEN = IPV4_ADDR_LEN, /* Ip address length in bytes */
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};
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static const Ipv4_address CURRENT; /* current network */
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static const Ipv4_address BROADCAST; /* broadcast address */
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static Ipv4_address ip_from_string(const char *ip);
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static Genode::uint16_t calculate_checksum(Ipv4_packet const &packet);
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private:
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/************************
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** IPv4 header fields **
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************************/
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unsigned _header_length : 4;
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unsigned _version : 4;
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Genode::uint8_t _diff_service;
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Genode::uint16_t _total_length;
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Genode::uint16_t _identification;
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unsigned _flags : 3;
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unsigned _fragment_offset : 13;
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Genode::uint8_t _time_to_live;
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Genode::uint8_t _protocol;
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Genode::uint16_t _header_checksum;
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Genode::uint8_t _src_addr[ADDR_LEN];
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Genode::uint8_t _dst_addr[ADDR_LEN];
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unsigned _data[0];
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/**
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* Bitmasks for differentiated services field.
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*/
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enum Differentiated_services {
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PRECEDENCE = 0x7,
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DELAY = 0x8,
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THROUGHPUT = 0x10,
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RELIABILITY = 0x20,
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COST = 0x40
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};
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public:
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enum Precedence {
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NETWORK_CONTROL = 7,
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INTERNETWORK_CONTROL = 6,
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CRITIC_ECP = 5,
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FLASH_OVERRIDE = 4,
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FLASH = 3,
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IMMEDIATE = 2,
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PRIORITY = 1,
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ROUTINE = 0
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};
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enum Flags {
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NO_FRAGMENT = 0x2,
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MORE_FRAGMENTS = 0x4
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};
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/**
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* Exception used to indicate protocol violation.
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*/
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class No_ip_packet : Genode::Exception {};
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/*****************
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** Constructor **
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*****************/
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Ipv4_packet(Genode::size_t size) {
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/* ip header needs to fit in */
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if (size < sizeof(Ipv4_packet))
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throw No_ip_packet();
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}
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/*******************************
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** IPv4 field read-accessors **
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*******************************/
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Genode::uint8_t version() { return _version; }
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/* returns the number of 32-bit words the header occupies */
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Genode::uint8_t header_length() { return _header_length; }
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Genode::uint8_t precedence() { return _diff_service & PRECEDENCE; }
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bool low_delay() { return _diff_service & DELAY; }
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bool high_throughput() { return _diff_service & THROUGHPUT; }
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bool high_reliability() { return _diff_service & RELIABILITY;}
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bool minimize_monetary_cost() { return _diff_service & COST; }
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Genode::uint16_t total_length() { return host_to_big_endian(_total_length); }
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Genode::uint16_t identification() { return host_to_big_endian(_identification); }
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bool no_fragmentation() { return _flags & NO_FRAGMENT; }
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bool more_fragments() { return _flags & MORE_FRAGMENTS; }
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Genode::size_t fragment_offset() { return _fragment_offset; }
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Genode::uint8_t time_to_live() { return _time_to_live; }
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Genode::uint8_t protocol() const { return _protocol; }
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Genode::uint16_t checksum() { return host_to_big_endian(_header_checksum); }
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Ipv4_address dst() const { return Ipv4_address((void *)&_dst_addr); }
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Ipv4_address src() const { return Ipv4_address((void *)&_src_addr); }
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template <typename T> T const * header() const { return (T const *)(this); }
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template <typename T> T * data() { return (T *)(_data); }
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template <typename T> T const * data() const { return (T const *)(_data); }
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/********************************
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** IPv4 field write-accessors **
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********************************/
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void version(Genode::size_t version) { _version = version; }
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void header_length(Genode::size_t len) { _header_length = len; }
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void total_length(Genode::uint16_t len) { _total_length = host_to_big_endian(len); }
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void time_to_live(Genode::uint8_t ttl) { _time_to_live = ttl; }
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void checksum(Genode::uint16_t checksum) { _header_checksum = host_to_big_endian(checksum); }
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void dst(Ipv4_address ip) { ip.copy(&_dst_addr); }
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void src(Ipv4_address ip) { ip.copy(&_src_addr); }
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/***************
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** Operators **
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***************/
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/**
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* Placement new.
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*/
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void * operator new(__SIZE_TYPE__ size, void* addr) { return addr; }
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/*********
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** log **
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*********/
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void print(Genode::Output &output) const;
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} __attribute__((packed));
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struct Net::Ipv4_address_prefix
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{
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Ipv4_address address;
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Genode::uint8_t prefix = 32;
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bool valid() const { return address.valid() || !prefix; }
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void print(Genode::Output &output) const;
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bool prefix_matches(Ipv4_address const &ip) const;
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};
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namespace Genode {
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inline size_t ascii_to(char const *s, Net::Ipv4_address &result);
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inline size_t ascii_to(char const *s, Net::Ipv4_address_prefix &result);
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}
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Genode::size_t Genode::ascii_to(char const *s, Net::Ipv4_address &result)
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{
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Net::Ipv4_address buf;
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size_t number_idx = 0;
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size_t read_len = 0;
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while (1) {
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/* read the current number, fail if there's no number */
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size_t number_len = ascii_to_unsigned(s, buf.addr[number_idx], 10);
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if (!number_len) {
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return 0; }
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/* update read length and number index */
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read_len += number_len;
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number_idx++;
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/* if we have all numbers, fill result and return read length */
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if (number_idx == sizeof(buf.addr) / sizeof(buf.addr[0])) {
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result = buf;
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return read_len;
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}
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/* as it was not the last number, check for the following dot */
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s += number_len;
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if (*s != '.') {
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return 0; }
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read_len++;
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s++;
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}
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}
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Genode::size_t Genode::ascii_to(char const *s, Net::Ipv4_address_prefix &result)
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{
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/* read the leading IPv4 address, fail if there's no address */
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Net::Ipv4_address_prefix buf;
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size_t read_len = ascii_to(s, buf.address);
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if (!read_len) {
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return 0; }
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/* check for the following slash */
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s += read_len;
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if (*s != '/') {
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return 0; }
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read_len++;
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s++;
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/* read the prefix, fail if there's no prefix */
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size_t prefix_len = ascii_to_unsigned(s, buf.prefix, 10);
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if (!prefix_len) {
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return 0; }
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/* fill result and return read length */
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result = buf;
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return read_len + prefix_len;
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}
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#endif /* _IPV4_H_ */
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