151 lines
3.5 KiB
C++
151 lines
3.5 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 "ip.hh"
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#include "core/print.hh"
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namespace net {
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std::ostream& operator<<(std::ostream& os, ipv4_address a) {
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auto ip = a.ip;
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return fprint(os, "%d.%d.%d.%d",
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(ip >> 24) & 0xff,
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(ip >> 16) & 0xff,
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(ip >> 8) & 0xff,
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(ip >> 0) & 0xff);
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}
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uint16_t ip_checksum(const void* data, size_t len) {
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uint64_t csum = 0;
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auto p64 = reinterpret_cast<const packed<uint64_t>*>(data);
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while (len >= 8) {
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auto old = csum;
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csum += ntohq(*p64++);
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csum += (csum < old);
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len -= 8;
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}
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auto p16 = reinterpret_cast<const packed<uint16_t>*>(p64);
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while (len >= 2) {
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auto old = csum;
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csum += ntohs(*p16++);
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csum += (csum < old);
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len -= 2;
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}
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auto p8 = reinterpret_cast<const uint8_t*>(p16);
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if (len) {
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auto old = csum;
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csum += *p8++ << 8;
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csum += (csum < old);
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len -= 1;
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}
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csum = (csum & 0xffff) + ((csum >> 16) & 0xffff) + ((csum >> 32) & 0xffff) + (csum >> 48);
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csum += csum >> 16;
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return htons(~csum);
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}
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ipv4::ipv4(interface* netif)
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: _netif(netif)
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, _global_arp(netif)
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, _arp(_global_arp)
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, _l3(netif, 0x0800)
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, _tcp(*this)
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, _l4({ { 6, &_tcp } }) {
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run();
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}
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bool ipv4::in_my_netmask(ipv4_address a) const {
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return !((a.ip ^ _host_address.ip) & _netmask.ip);
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}
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void ipv4::run() {
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_l3.receive().then([this] (packet p, ethernet_address from) {
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handle_received_packet(std::move(p), from);
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run();
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});
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}
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void ipv4::handle_received_packet(packet p, ethernet_address from) {
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auto iph = p.get_header<ip_hdr>(0);
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if (!iph) {
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return;
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}
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ntoh(*iph);
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// FIXME: process options
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if (in_my_netmask(iph->src_ip) && iph->src_ip != _host_address) {
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_arp.learn(from, iph->src_ip);
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}
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if (iph->frag & 0x3fff) {
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// FIXME: defragment
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return;
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}
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if (iph->dst_ip != _host_address) {
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// FIXME: forward
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return;
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}
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auto l4 = _l4[iph->ip_proto];
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if (l4) {
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p.trim_front(iph->ihl * 4);
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l4->received(std::move(p), iph->src_ip, iph->dst_ip);
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}
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}
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void ipv4::send(ipv4_address to, uint8_t proto_num, packet p) {
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// FIXME: fragment
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auto iph = p.prepend_header<ip_hdr>();
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iph->ihl = sizeof(*iph) / 4;
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iph->ver = 4;
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iph->dscp = 0;
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iph->ecn = 0;
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iph->len = p.len;
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iph->id = 0;
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iph->frag = 0;
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iph->ttl = 64;
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iph->ip_proto = proto_num;
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iph->csum = 0;
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iph->src_ip = _host_address;
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// FIXME: routing
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auto gw = to;
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iph->dst_ip = to;
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hton(*iph);
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checksummer csum;
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csum.sum(reinterpret_cast<char*>(iph), sizeof(*iph));
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iph->csum = csum.get();
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_arp.lookup(gw).then([this, p = std::move(p)] (ethernet_address e_dst) mutable {
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_send_sem.wait().then([this, e_dst, p = std::move(p)] () mutable {
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return _l3.send(e_dst, std::move(p));
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}).then([this] {
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_send_sem.signal();
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});
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});
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}
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void ipv4::set_host_address(ipv4_address ip) {
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_host_address = ip;
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_arp.set_self_addr(ip);
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}
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void checksummer::sum(const char* data, size_t len) {
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auto orig_len = len;
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if (odd) {
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partial += uint8_t(*data++);
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--len;
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}
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partial += ip_checksum(data, len);
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odd ^= orig_len & 1;
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}
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void checksummer::sum(const packet& p) {
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for (auto&& f : p.fragments) {
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sum(f.base, f.size);
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}
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}
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uint16_t checksummer::get() const {
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return partial + (partial >> 16);
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}
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}
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