7b47c8f0c6
Issue #2953
373 lines
10 KiB
C++
373 lines
10 KiB
C++
/*
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* \brief Test the reachability of a host on an IP network
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* \author Martin Stein
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* \date 2018-03-27
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*/
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/*
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* Copyright (C) 2018 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 Affero General Public License version 3.
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*/
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/* local includes */
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#include <nic.h>
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#include <ipv4_config.h>
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#include <dhcp_client.h>
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#include <protocol.h>
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/* Genode includes */
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#include <net/ipv4.h>
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#include <net/ethernet.h>
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#include <net/arp.h>
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#include <net/tcp.h>
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#include <net/icmp.h>
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#include <base/component.h>
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#include <base/heap.h>
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#include <base/attached_rom_dataspace.h>
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#include <timer_session/connection.h>
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using namespace Net;
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using namespace Genode;
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class Main : public Nic_handler,
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public Dhcp_client_handler
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{
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private:
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using Periodic_timeout = Timer::Periodic_timeout<Main>;
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struct Bad_protocol : Exception { };
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enum { IPV4_TIME_TO_LIVE = 64 };
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enum { ICMP_SEQ = 1 };
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enum { SRC_PORT = 50000 };
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enum { FIRST_DST_PORT = 49152 };
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enum { LAST_DST_PORT = 65535 };
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Env &_env;
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Attached_rom_dataspace _config_rom { _env, "config" };
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Xml_node _config { _config_rom.xml() };
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Timer::Connection _timer { _env };
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Microseconds _period_us { 1 };
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Constructible<Periodic_timeout> _period { };
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Heap _heap { &_env.ram(), &_env.rm() };
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bool const _verbose { _config.attribute_value("verbose", false) };
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Net::Nic _nic { _env, _heap, *this, _verbose };
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Ipv4_address const _dst_ip { _config.attribute_value("dst_ip", Ipv4_address()) };
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Mac_address _dst_mac { };
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Constructible<Dhcp_client> _dhcp_client { };
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Reconstructible<Ipv4_config> _ip_config { _config.attribute_value("interface", Ipv4_address_prefix()),
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_config.attribute_value("gateway", Ipv4_address()),
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Ipv4_address() };
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Protocol const _protocol { _config.attribute_value("protocol", Protocol::ICMP) };
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Port _dst_port { FIRST_DST_PORT };
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size_t _ping_sz { _init_ping_sz() };
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size_t _init_ping_sz() const;
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void _handle_arp(Ethernet_frame ð,
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Size_guard &size_guard);
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void _broadcast_arp_request(Ipv4_address const &ip);
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void _send_arp_reply(Ethernet_frame &req_eth,
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Arp_packet &req_arp);
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void _send_ping(Duration not_used = Duration(Microseconds(0)));
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public:
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struct Invalid_arguments : Exception { };
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Main(Env &env);
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/*****************
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** Nic_handler **
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*****************/
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void handle_eth(Ethernet_frame ð,
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Size_guard &size_guard) override;
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/*************************
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** Dhcp_client_handler **
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*************************/
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void ip_config(Ipv4_config const &ip_config) override;
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Ipv4_config const &ip_config() const override { return *_ip_config; }
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};
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void Main::ip_config(Ipv4_config const &ip_config)
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{
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if (_verbose) {
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log("IP config: ", ip_config); }
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_ip_config.construct(ip_config);
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_period.construct(_timer, *this, &Main::_send_ping, _period_us);
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}
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Main::Main(Env &env) : _env(env)
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{
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/* exit unsuccessful if parameters are invalid */
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if (_dst_ip == Ipv4_address()) {
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throw Invalid_arguments(); }
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/* if there is a static IP config, start sending pings periodically */
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if (ip_config().valid) {
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_period.construct(_timer, *this, &Main::_send_ping, _period_us); }
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/* else, start the DHCP client for requesting an IP config */
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else {
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_dhcp_client.construct(_heap, _timer, _nic, *this); }
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}
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void Main::handle_eth(Ethernet_frame ð,
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Size_guard &size_guard)
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{
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try {
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/* print receipt message */
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if (_verbose) {
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log("rcv ", eth); }
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if (!ip_config().valid) {
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_dhcp_client->handle_eth(eth, size_guard); }
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/* drop packet if ETH does not target us */
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if (eth.dst() != _nic.mac() &&
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eth.dst() != Ethernet_frame::broadcast())
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{
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if (_verbose) {
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log("bad ETH destination"); }
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return;
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}
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/* select ETH sub-protocol */
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switch (eth.type()) {
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case Ethernet_frame::Type::ARP: _handle_arp(eth, size_guard); break;
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default: ; }
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}
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catch (Drop_packet_inform exception) {
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if (_verbose) {
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log("drop packet: ", exception.msg); }
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}
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}
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void Main::_handle_arp(Ethernet_frame ð,
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Size_guard &size_guard)
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{
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/* check ARP protocol- and hardware address type */
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Arp_packet &arp = eth.data<Arp_packet>(size_guard);
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if (!arp.ethernet_ipv4()) {
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error("ARP for unknown protocol"); }
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/* check ARP operation */
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switch (arp.opcode()) {
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case Arp_packet::REPLY:
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/* check whether we waited for this ARP reply */
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if (_dst_mac != Mac_address()) {
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return; }
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if (ip_config().interface.prefix_matches(_dst_ip)) {
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if (arp.src_ip() != _dst_ip) {
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return; }
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} else {
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if (arp.src_ip() != ip_config().gateway) {
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return; }
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}
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/* set destination MAC address and retry to ping */
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_dst_mac = arp.src_mac();
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return;
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case Arp_packet::REQUEST:
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/* check whether the ARP request targets us */
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if (arp.dst_ip() != ip_config().interface.address) {
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return; }
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_send_arp_reply(eth, arp);
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default: ; }
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}
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size_t Main::_init_ping_sz() const
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{
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enum { IP_SZ = sizeof(Ethernet_frame) + sizeof(Ipv4_packet) };
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switch (_protocol) {
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case Protocol::ICMP: return IP_SZ + sizeof(Icmp_packet);
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case Protocol::UDP: return IP_SZ + sizeof(Udp_packet);
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case Protocol::TCP: return IP_SZ + sizeof(Tcp_packet);
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default: throw Bad_protocol();
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}
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}
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void Main::_send_arp_reply(Ethernet_frame &req_eth,
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Arp_packet &req_arp)
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{
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_nic.send(sizeof(Ethernet_frame) + sizeof(Arp_packet),
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[&] (void *pkt_base, Size_guard &size_guard)
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{
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/* write Ethernet header */
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Ethernet_frame ð = Ethernet_frame::construct_at(pkt_base, size_guard);
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eth.dst(req_eth.src());
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eth.src(_nic.mac());
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eth.type(Ethernet_frame::Type::ARP);
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/* write ARP header */
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Arp_packet &arp = eth.construct_at_data<Arp_packet>(size_guard);
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arp.hardware_address_type(Arp_packet::ETHERNET);
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arp.protocol_address_type(Arp_packet::IPV4);
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arp.hardware_address_size(sizeof(Mac_address));
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arp.protocol_address_size(sizeof(Ipv4_address));
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arp.opcode(Arp_packet::REPLY);
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arp.src_mac(_nic.mac());
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arp.src_ip(ip_config().interface.address);
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arp.dst_mac(req_eth.src());
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arp.dst_ip(req_arp.src_ip());
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});
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}
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void Main::_broadcast_arp_request(Ipv4_address const &dst_ip)
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{
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_nic.send(sizeof(Ethernet_frame) + sizeof(Arp_packet),
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[&] (void *pkt_base, Size_guard &size_guard)
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{
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/* write Ethernet header */
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Ethernet_frame ð = Ethernet_frame::construct_at(pkt_base, size_guard);
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eth.dst(Mac_address(0xff));
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eth.src(_nic.mac());
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eth.type(Ethernet_frame::Type::ARP);
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/* write ARP header */
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Arp_packet &arp = eth.construct_at_data<Arp_packet>(size_guard);
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arp.hardware_address_type(Arp_packet::ETHERNET);
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arp.protocol_address_type(Arp_packet::IPV4);
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arp.hardware_address_size(sizeof(Mac_address));
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arp.protocol_address_size(sizeof(Ipv4_address));
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arp.opcode(Arp_packet::REQUEST);
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arp.src_mac(_nic.mac());
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arp.src_ip(ip_config().interface.address);
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arp.dst_mac(Mac_address(0xff));
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arp.dst_ip(dst_ip);
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});
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}
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void Main::_send_ping(Duration)
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{
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/* if we do not yet know the Ethernet destination, request it via ARP */
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if (_dst_mac == Mac_address()) {
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if (ip_config().interface.prefix_matches(_dst_ip)) {
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_broadcast_arp_request(_dst_ip); }
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else {
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_broadcast_arp_request(ip_config().gateway); }
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return;
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}
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try {
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while (true) {
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_nic.send(_ping_sz, [&] (void *pkt_base, Size_guard &size_guard)
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{
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/* create ETH header */
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Ethernet_frame ð = Ethernet_frame::construct_at(pkt_base, size_guard);
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eth.dst(_dst_mac);
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eth.src(_nic.mac());
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eth.type(Ethernet_frame::Type::IPV4);
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/* create IP header */
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size_t const ip_off = size_guard.head_size();
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Ipv4_packet &ip = eth.construct_at_data<Ipv4_packet>(size_guard);
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ip.header_length(sizeof(Ipv4_packet) / 4);
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ip.version(4);
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ip.time_to_live(IPV4_TIME_TO_LIVE);
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ip.src(ip_config().interface.address);
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ip.dst(_dst_ip);
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/* select IP-encapsulated protocol */
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switch (_protocol) {
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case Protocol::ICMP:
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{
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/* adapt IP header to ICMP */
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ip.protocol(Ipv4_packet::Protocol::ICMP);
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/* create ICMP header */
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Icmp_packet &icmp = ip.construct_at_data<Icmp_packet>(size_guard);
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icmp.type(Icmp_packet::Type::ECHO_REQUEST);
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icmp.code(Icmp_packet::Code::ECHO_REQUEST);
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icmp.query_id(_dst_port.value);
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icmp.query_seq(ICMP_SEQ);
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icmp.update_checksum(0);
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/* prepare next ICMP ping */
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if (_dst_port.value == LAST_DST_PORT) {
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_dst_port.value = FIRST_DST_PORT; }
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else {
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_dst_port.value++; }
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break;
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}
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case Protocol::UDP:
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{
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/* adapt IP header to UDP */
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ip.protocol(Ipv4_packet::Protocol::UDP);
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/* create UDP header */
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size_t const udp_off = size_guard.head_size();
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Udp_packet &udp = ip.construct_at_data<Udp_packet>(size_guard);
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udp.src_port(Port(SRC_PORT));
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udp.dst_port(_dst_port);
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/* finish UDP header */
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udp.length(size_guard.head_size() - udp_off);
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udp.update_checksum(ip.src(), ip.dst());
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/* prepare next ping */
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if (_dst_port.value == LAST_DST_PORT) {
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_dst_port.value = FIRST_DST_PORT; }
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else {
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_dst_port.value++; }
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break;
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}
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case Protocol::TCP:
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{
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/* adapt IP header to TCP */
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ip.protocol(Ipv4_packet::Protocol::TCP);
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/* create TCP header */
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size_t const tcp_off = size_guard.head_size();
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Tcp_packet &tcp = ip.construct_at_data<Tcp_packet>(size_guard);
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tcp.src_port(Port(SRC_PORT));
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tcp.dst_port(_dst_port);
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/* finish TCP header */
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tcp.update_checksum(ip.src(), ip.dst(), size_guard.head_size() - tcp_off);
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/* prepare next ping */
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if (_dst_port.value == LAST_DST_PORT) {
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_dst_port.value = FIRST_DST_PORT; }
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else {
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_dst_port.value++; }
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break;
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}
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}
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/* finish IP header */
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ip.total_length(size_guard.head_size() - ip_off);
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ip.update_checksum();
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});
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}
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}
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catch (Net::Packet_stream_source::Packet_alloc_failed) { }
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}
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void Component::construct(Env &env) { static Main main(env); }
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