d698811bdd
Some packets, like arp replies, are broadcast to all cpus for handling, but only packet structure is copied for each cpu, the actual packet data is the same for all of them. Currently networking stack mangles a packet data during its travel up the stack while doing ntoh() translations which cannot obviously work for broadcaster packets. This patches fixes the code to not modify packet data while doing ntoh(), but do it in a stack allocated copy of a data instead.
76 lines
2.0 KiB
C++
76 lines
2.0 KiB
C++
/*
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* Copyright (C) 2014 Cloudius Systems, Ltd.
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*
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*/
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#include "net/virtio.hh"
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#include "core/reactor.hh"
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#include "net/ip.hh"
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#include <iostream>
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#include <utility>
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#include <algorithm>
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using namespace net;
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void dump_packet(const packet& p) {
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std::cout << "rx:";
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auto f = p.frag(0);
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for (unsigned i = 0; i < std::min(f.size, size_t(30)); ++i) {
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char x[4];
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std::sprintf(x, " %02x", uint8_t(f.base[i]));
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std::cout << x;
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}
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std::cout << "\n";
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}
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future<> echo_packet(net::device& netif, packet p) {
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auto f = p.frag(0);
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if (f.size < sizeof(eth_hdr)) {
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return make_ready_future<>();
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}
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auto pos = 0;
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auto eh = reinterpret_cast<eth_hdr*>(f.base + pos);
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pos += sizeof(*eh);
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*eh = ntoh(*eh);
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if (eh->eth_proto != 0x0800) {
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return make_ready_future<>();
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}
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auto iph = reinterpret_cast<ip_hdr*>(f.base + pos);
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*iph = ntoh(*iph);
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pos += iph->ihl * 4;
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if (iph->ver != 4 || iph->ihl < 5 || iph->ip_proto != 1) {
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return make_ready_future<>();
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}
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auto ip_len = iph->len;
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auto icmph = reinterpret_cast<icmp_hdr*>(f.base + pos);
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if (icmph->type != icmp_hdr::msg_type::echo_request) {
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return make_ready_future<>();
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}
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auto icmp_len = ip_len - iph->ihl * 4;
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std::swap(eh->src_mac, eh->dst_mac);
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eh->src_mac = {{{ 0x12, 0x23, 0x45, 0x56, 0x67, 0x68 }}};
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auto x = iph->src_ip;
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iph->src_ip = ipv4_address("192.168.122.2");
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iph->dst_ip = x;
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icmph->type = icmp_hdr::msg_type::echo_reply;
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icmph->csum = 0;
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*iph = hton(*iph);
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*eh = hton(*eh);
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icmph->csum = ip_checksum(icmph, icmp_len);
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iph->csum = 0;
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iph->csum = ip_checksum(iph, iph->ihl * 4);
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return netif.send(std::move(p));
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}
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int main(int ac, char** av) {
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auto vnet = create_virtio_net_device("tap0");
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subscription<packet> rx = vnet->receive([netif = vnet.get(), &rx] (packet p) {
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dump_packet(p);
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return echo_packet(*netif, std::move(p));
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});
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engine.run();
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return 0;
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}
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