11a297b557
The Ethernet payload may be followed by padding of variable length and the FCS (Frame Check Sequence). Thus, we should consider the value "Ethernet-frame size minus Ethernet-header size" to be only the maximum size of the encapsulated IP packet. But until now, we considered it to be also the actual size of the encapsulated IP packet. This commit fixes the problem for all affected components of the Genode base-repository. Fixes #2775
141 lines
3.7 KiB
C++
141 lines
3.7 KiB
C++
/*
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* \brief NIC handler
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* \author Stefan Kalkowski
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* \date 2013-05-24
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*/
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/*
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* Copyright (C) 2013-2017 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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#include <base/env.h>
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#include <net/ethernet.h>
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#include <net/arp.h>
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#include <net/ipv4.h>
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#include <net/udp.h>
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#include <net/dhcp.h>
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#include <component.h>
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using namespace Net;
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using namespace Genode;
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bool Net::Nic::handle_arp(Ethernet_frame *eth, Genode::size_t size) {
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Arp_packet &arp = eth->data<Arp_packet>(size - sizeof(Ethernet_frame));
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/* ignore broken packets */
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if (!arp.ethernet_ipv4())
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return true;
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/* look whether the IP address is one of our client's */
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Ipv4_address_node *node = vlan().ip_tree.first();
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if (node)
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node = node->find_by_address(arp.dst_ip());
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if (node) {
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if (arp.opcode() == Arp_packet::REQUEST) {
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/*
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* The ARP packet gets re-written, we interchange source
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* and destination MAC and IP addresses, and set the opcode
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* to reply, and then push the packet back to the NIC driver.
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*/
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Ipv4_address old_src_ip = arp.src_ip();
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arp.opcode(Arp_packet::REPLY);
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arp.dst_mac(arp.src_mac());
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arp.src_mac(mac());
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arp.src_ip(arp.dst_ip());
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arp.dst_ip(old_src_ip);
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eth->dst(arp.dst_mac());
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/* set our MAC as sender */
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eth->src(mac());
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send(eth, size);
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} else {
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/* overwrite destination MAC */
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arp.dst_mac(node->component().mac_address().addr);
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eth->dst(node->component().mac_address().addr);
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node->component().send(eth, size);
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}
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return false;
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}
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return true;
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}
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bool Net::Nic::handle_ip(Ethernet_frame *eth, Genode::size_t size) {
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size_t const ip_max_size = size - sizeof(Ethernet_frame);
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Ipv4_packet &ip = eth->data<Ipv4_packet>(ip_max_size);
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size_t const ip_size = ip.size(ip_max_size);
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/* is it an UDP packet ? */
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if (ip.protocol() == Ipv4_packet::Protocol::UDP)
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{
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size_t const udp_size = ip_size - sizeof(Ipv4_packet);
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Udp_packet &udp = ip.data<Udp_packet>(udp_size);
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/* is it a DHCP packet ? */
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if (Dhcp_packet::is_dhcp(&udp)) {
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size_t const dhcp_size = udp_size - sizeof(Udp_packet);
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Dhcp_packet &dhcp = udp.data<Dhcp_packet>(dhcp_size);
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/* check for DHCP ACKs containing new client ips */
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if (dhcp.op() == Dhcp_packet::REPLY) {
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try {
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Dhcp_packet::Message_type const msg_type =
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dhcp.option<Dhcp_packet::Message_type_option>().value();
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/*
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* Extract the IP address and set it in the client's
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* session-component
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*/
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if (msg_type == Dhcp_packet::Message_type::ACK) {
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Mac_address_node *node =
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vlan().mac_tree.first();
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if (node)
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node = node->find_by_address(dhcp.client_mac());
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if (node)
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node->component().set_ipv4_address(dhcp.yiaddr());
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}
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}
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catch (Dhcp_packet::Option_not_found) { }
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}
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}
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}
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/* is it an unicast message to one of our clients ? */
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if (eth->dst() == mac()) {
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Ipv4_address_node *node = vlan().ip_tree.first();
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if (node) {
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node = node->find_by_address(ip.dst());
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if (node) {
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/* overwrite destination MAC */
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eth->dst(node->component().mac_address().addr);
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/* deliver the packet to the client */
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node->component().send(eth, size);
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return false;
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}
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}
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}
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return true;
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}
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Net::Nic::Nic(Genode::Env &env, Genode::Heap &heap, Net::Vlan &vlan)
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: Packet_handler(env.ep(), vlan),
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_tx_block_alloc(&heap),
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_nic(env, &_tx_block_alloc, BUF_SIZE, BUF_SIZE),
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_mac(_nic.mac_address().addr)
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{
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_nic.rx_channel()->sigh_ready_to_ack(_sink_ack);
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_nic.rx_channel()->sigh_packet_avail(_sink_submit);
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_nic.tx_channel()->sigh_ack_avail(_source_ack);
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_nic.tx_channel()->sigh_ready_to_submit(_source_submit);
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_nic.link_state_sigh(_client_link_state);
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}
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