void IP4::transmit(Packet_ptr pckt) {
assert(pckt->size() > sizeof(IP4::full_header));
auto ip4_pckt = std::static_pointer_cast<PacketIP4>(pckt);
ip4_pckt->make_flight_ready();
IP4::ip_header& hdr = ip4_pckt->ip4_header();
// Create local and target subnets
addr target = hdr.daddr & stack_.netmask();
addr local = stack_.ip_addr() & stack_.netmask();
// Compare subnets to know where to send packet
pckt->next_hop(target == local ? hdr.daddr : stack_.router());
debug("<IP4 TOP> Next hop for %s, (netmask %s, local IP: %s, gateway: %s) == %s\n",
hdr.daddr.str().c_str(),
stack_.netmask().str().c_str(),
stack_.ip_addr().str().c_str(),
stack_.router().str().c_str(),
target == local ? "DIRECT" : "GATEWAY");
debug("<IP4 transmit> my ip: %s, Next hop: %s, Packet size: %i IP4-size: %i\n",
stack_.ip_addr().str().c_str(),
pckt->next_hop().str().c_str(),
pckt->size(),
ip4_pckt->ip4_segment_size()
);
linklayer_out_(pckt);
}
int Arp::transmit(Packet_ptr pckt){
assert(pckt->size());
/** Get destination IP from IP header */
IP4::ip_header* iphdr = (IP4::ip_header*)(pckt->buffer()
+ sizeof(Ethernet::header));
IP4::addr sip = iphdr->saddr;
IP4::addr dip = pckt->next_hop();
debug2("<ARP -> physical> Transmitting %i bytes to %s \n",
pckt->size(),dip.str().c_str());
Ethernet::addr mac;
if (iphdr->daddr == IP4::INADDR_BCAST)
{
// when broadcasting our source IP should be either
// our own IP or 0.0.0.0
static const IP4::addr INADDR_NONE {{0}};
if (sip != ip_ && sip != INADDR_NONE)
{
debug2("<ARP> Dropping outbound broadcast packet due to "
"invalid source IP %s\n", sip.str().c_str());
return -1;
}
mac = Ethernet::addr::BROADCAST_FRAME;
}
else
{
if (sip != ip_)
{
debug2("<ARP -> physical> Not bound to source IP %s. My IP is %s. DROP!\n",
sip.str().c_str(), ip_.str().c_str());
return -1;
}
// If we don't have a cached IP, get mac from next-hop (Håreks c001 hack)
if (!is_valid_cached(dip))
return arp_resolver_(pckt);
// Get mac from cache
mac = cache_[dip].mac_;
}
/** Attach next-hop mac and ethertype to ethernet header */
Ethernet::header* ethhdr = (Ethernet::header*)pckt->buffer();
ethhdr->src = mac_;
ethhdr->dest.major = mac.major;
ethhdr->dest.minor = mac.minor;
ethhdr->type = Ethernet::ETH_IP4;
debug2("<ARP -> physical> Sending packet to %s \n",mac.str().c_str());
return linklayer_out_(pckt);
}
int Arp::bottom(Packet_ptr pckt)
{
debug2("<ARP handler> got %i bytes of data \n", pckt->size());
header* hdr = (header*) pckt->buffer();
//debug2("\t OPCODE: 0x%x \n",hdr->opcode);
//debug2("Chaching IP %s for %s \n", hdr->sipaddr.str().c_str() , hdr->shwaddr.str().c_str())
debug2("Have valid cache? %s \n",is_valid_cached(hdr->sipaddr) ? "YES":"NO");
cache(hdr->sipaddr, hdr->shwaddr);
switch(hdr->opcode){
case H_request:
debug2("\t ARP REQUEST: ");
debug2("%s is looking for %s \n",
hdr->sipaddr.str().c_str(),hdr->dipaddr.str().c_str());
if (hdr->dipaddr == ip_)
arp_respond(hdr);
else
{
debug2("\t NO MATCH for My IP (%s). DROP!\n",
ip().str().c_str());
}
break;
case H_reply:
{
debug2("\t ARP REPLY: %s belongs to %s\n",
hdr->sipaddr.str().c_str(), hdr->shwaddr.str().c_str());
auto waiting = waiting_packets_.find(hdr->sipaddr);
if (waiting != waiting_packets_.end()) {
debug ("Had a packet waiting for this IP. Sending\n");
transmit(waiting->second);
waiting_packets_.erase(waiting);
}
}
break;
default:
debug2("\t UNKNOWN OPCODE \n");
break;
}
// Free the buffer (We're leaf node for this one's path)
// @todo Freeing here corrupts the outgoing frame. Why?
//free(data);
return 0 + 0 * pckt->size(); // yep, it's what you think it is (and what's that?!)
};
void Ethernet::receive(Packet_ptr pckt) {
Expects(pckt->size() > 0);
header* eth = reinterpret_cast<header*>(pckt->buffer());
/** Do we pass on ethernet headers? As for now, yes.
data += sizeof(header);
len -= sizeof(header);
*/
debug2("<Ethernet IN> %s => %s , Eth.type: 0x%x ",
eth->src.str().c_str(), eth->dest.str().c_str(), eth->type);
// Stat increment packets received
packets_rx_++;
bool dropped = false;
switch(eth->type) {
case ETH_IP4:
debug2("IPv4 packet\n");
ip4_upstream_(std::move(pckt));
break;
case ETH_IP6:
debug2("IPv6 packet\n");
ip6_upstream_(std::move(pckt));
break;
case ETH_ARP:
debug2("ARP packet\n");
arp_upstream_(std::move(pckt));
break;
case ETH_WOL:
dropped = true;
debug2("Wake-on-LAN packet\n");
break;
case ETH_VLAN:
dropped = true;
debug("VLAN tagged frame (not yet supported)");
break;
default:
dropped = true;
// This might be 802.3 LLC traffic
if (net::ntohs(eth->type) > 1500) {
debug2("<Ethernet> UNKNOWN ethertype 0x%x\n", ntohs(eth->type));
}else {
debug2("IEEE802.3 Length field: 0x%x\n", ntohs(eth->type));
}
break;
}
if(dropped)
packets_dropped_++;
}
void Arp::receive(Packet_ptr pckt) {
PRINT("<ARP handler> got %i bytes of data\n", pckt->size());
header* hdr = reinterpret_cast<header*>(pckt->layer_begin());
/// cache entry
this->cache(hdr->sipaddr, hdr->shwaddr);
/// always try to ship waiting packets when someone talks
auto waiting = waiting_packets_.find(hdr->sipaddr);
if (waiting != waiting_packets_.end()) {
PRINT("<Arp> Had a packet waiting for this IP. Sending\n");
transmit(std::move(waiting->second.pckt), hdr->sipaddr);
waiting_packets_.erase(waiting);
}
switch(hdr->opcode) {
case H_request: {
// Stat increment requests received
requests_rx_++;
PRINT("<Arp> %s is looking for %s\n",
hdr->sipaddr.str().c_str(),
hdr->dipaddr.str().c_str());
if (hdr->dipaddr == inet_.ip_addr()) {
// The packet is for us. Respond.
arp_respond(hdr, inet_.ip_addr());
} else if (proxy_ and proxy_(hdr->dipaddr)){
// The packet is for an IP to which we know a route
arp_respond(hdr, hdr->dipaddr);
} else {
// Drop
PRINT("\t NO MATCH for My IP (%s). DROP!\n",
inet_.ip_addr().str().c_str());
}
break;
}
case H_reply: {
// Stat increment replies received
replies_rx_++;
PRINT("\t ARP REPLY: %s belongs to %s (waiting: %u)\n",
hdr->sipaddr.str().c_str(), hdr->shwaddr.str().c_str(), waiting_packets_.size());
break;
}
default:
PRINT("\t UNKNOWN OPCODE\n");
break;
} //< switch(hdr->opcode)
}
void ICMPv4::bottom(Packet_ptr pckt) {
if (pckt->size() < sizeof(full_header)) // Drop if not a full header
return;
full_header* full_hdr = reinterpret_cast<full_header*>(pckt->buffer());
icmp_header* hdr = &full_hdr->icmp_hdr;
#ifdef DEBUG
auto ip_address = full_hdr->ip_hdr.saddr.str().c_str();
#endif
switch(hdr->type) {
case (ICMP_ECHO):
debug("<ICMP> PING from %s\n", ip_address);
ping_reply(full_hdr, pckt->size());
break;
case (ICMP_ECHO_REPLY):
debug("<ICMP> PING Reply from %s\n", ip_address);
break;
}
}
int Ethernet::bottom(Packet_ptr pckt)
{
assert(pckt->size() > 0);
header* eth = (header*) pckt->buffer();
/** Do we pass on ethernet headers? As for now, yes.
data += sizeof(header);
len -= sizeof(header);
*/
debug2("<Ethernet IN> %s => %s , Eth.type: 0x%x ",
eth->src.str().c_str(),
eth->dest.str().c_str(),eth->type);
switch(eth->type){
case ETH_IP4:
debug2("IPv4 packet \n");
return ip4_handler_(pckt);
case ETH_IP6:
debug2("IPv6 packet \n");
return ip6_handler_(pckt);
case ETH_ARP:
debug2("ARP packet \n");
return arp_handler_(pckt);
case ETH_WOL:
debug2("Wake-on-LAN packet \n");
break;
case ETH_VLAN:
debug("VLAN tagged frame (not yet supported)");
default:
// This might be 802.3 LLC traffic
if (net::ntohs(eth->type) > 1500){
debug("<Ethernet> UNKNOWN ethertype 0x%x\n",ntohs(eth->type));
}else{
debug2("IEEE802.3 Length field: 0x%x\n",ntohs(eth->type));
}
break;
}
return -1;
}
void Arp::bottom(Packet_ptr pckt) {
debug2("<ARP handler> got %i bytes of data\n", pckt->size());
header* hdr = reinterpret_cast<header*>(pckt->buffer());
debug2("Have valid cache? %s\n", is_valid_cached(hdr->sipaddr) ? "YES" : "NO");
cache(hdr->sipaddr, hdr->shwaddr);
switch(hdr->opcode) {
case H_request: {
// Stat increment requests received
requests_rx_++;
debug2("\t ARP REQUEST: ");
debug2("%s is looking for %s\n",
hdr->sipaddr.str().c_str(),
hdr->dipaddr.str().c_str());
if (hdr->dipaddr == inet_.ip_addr()) {
arp_respond(hdr);
} else {
debug2("\t NO MATCH for My IP (%s). DROP!\n",
inet_.ip_addr().str().c_str());
}
break;
}
case H_reply: {
// Stat increment replies received
replies_rx_++;
debug2("\t ARP REPLY: %s belongs to %s (waiting: %u)\n",
hdr->sipaddr.str().c_str(), hdr->shwaddr.str().c_str(), waiting_packets_.size());
auto waiting = waiting_packets_.find(hdr->sipaddr);
if (waiting != waiting_packets_.end()) {
debug("Had a packet waiting for this IP. Sending\n");
transmit(std::move(waiting->second));
waiting_packets_.erase(waiting);
}
break;
}
default:
debug2("\t UNKNOWN OPCODE\n");
break;
} //< switch(hdr->opcode)
}
void Arp::transmit(Packet_ptr pckt, IP4::addr next_hop) {
Expects(pckt->size());
PRINT("<ARP -> physical> Transmitting %u bytes to %s\n",
(uint32_t) pckt->size(), next_hop.str().c_str());
MAC::Addr dest_mac;
if (next_hop == IP4::ADDR_BCAST) {
dest_mac = MAC::BROADCAST;
} else {
#ifdef ARP_PASSTHROUGH
extern MAC::Addr linux_tap_device;
dest_mac = linux_tap_device;
#else
// If we don't have a cached IP, perform address resolution
auto cache_entry = cache_.find(next_hop);
if (UNLIKELY(cache_entry == cache_.end())) {
PRINT("<ARP> No cache entry for IP %s. Resolving. \n", next_hop.to_string().c_str());
await_resolution(std::move(pckt), next_hop);
return;
}
// Get MAC from cache
dest_mac = cache_[next_hop].mac();
#endif
PRINT("<ARP> Found cache entry for IP %s -> %s \n",
next_hop.to_string().c_str(), dest_mac.to_string().c_str());
}
// Move chain to linklayer
linklayer_out_(std::move(pckt), dest_mac, Ethertype::IP4);
}
int Ethernet::transmit(Packet_ptr pckt){
header* hdr = (header*)pckt->buffer();
// Verify ethernet header
assert(hdr->dest.major != 0 || hdr->dest.minor !=0);
assert(hdr->type != 0);
// Add source address
hdr->src.major = _mac.major;
hdr->src.minor = _mac.minor;
debug2("<Ethernet OUT> Transmitting %i b, from %s -> %s. Type: %i \n",
pckt->size(),hdr->src.str().c_str(), hdr->dest.str().c_str(),hdr->type);
return physical_out_(pckt);
}
int ICMP::bottom(Packet_ptr pckt){
if (pckt->size() < sizeof(full_header)) //Drop if not a full header.
return -1;
full_header* full_hdr = (full_header*)pckt->buffer();
icmp_header* hdr = &full_hdr->icmp_hdr;
switch(hdr->type)
{
case (ICMP_ECHO):
debug("<ICMP> PING from %s \n",full_hdr->ip_hdr.saddr.str().c_str());
ping_reply(full_hdr);
break;
case (ICMP_ECHO_REPLY):
debug("<ICMP> PING Reply from %s \n",full_hdr->ip_hdr.saddr.str().c_str());
break;
}
return 0;
}
void Arp::transmit(Packet_ptr pckt) {
assert(pckt->size());
/** Get destination IP from IP header */
IP4::ip_header* iphdr = reinterpret_cast<IP4::ip_header*>(pckt->buffer()
+ sizeof(Ethernet::header));
IP4::addr sip = iphdr->saddr;
IP4::addr dip = pckt->next_hop();
debug2("<ARP -> physical> Transmitting %i bytes to %s\n",
pckt->size(), dip.str().c_str());
Ethernet::addr dest_mac;
if (iphdr->daddr == IP4::INADDR_BCAST) {
// When broadcasting our source IP should be either
// our own IP or 0.0.0.0
if (sip != inet_.ip_addr() && sip != IP4::INADDR_ANY) {
debug2("<ARP> Dropping outbound broadcast packet due to "
"invalid source IP %s\n", sip.str().c_str());
return;
}
// mui importante
dest_mac = Ethernet::BROADCAST_FRAME;
} else {
if (sip != inet_.ip_addr()) {
debug2("<ARP -> physical> Not bound to source IP %s. My IP is %s. DROP!\n",
sip.str().c_str(), inet_.ip_addr().str().c_str());
return;
}
// If we don't have a cached IP, perform address resolution
if (!is_valid_cached(dip)) {
arp_resolver_(std::move(pckt));
return;
}
// Get MAC from cache
dest_mac = cache_[dip].mac_;
}
/** Attach next-hop mac and ethertype to ethernet header */
auto* ethhdr = reinterpret_cast<Ethernet::header*>(pckt->buffer());
ethhdr->src = mac_;
ethhdr->dest = dest_mac;
ethhdr->type = Ethernet::ETH_IP4;
/** Update chain as well */
auto* next = pckt->tail();
while(next) {
auto* headur = reinterpret_cast<Ethernet::header*>(next->buffer());
headur->src = mac_;
headur->dest = dest_mac;
headur->type = Ethernet::ETH_IP4;
next = next->tail();
}
debug2("<ARP -> physical> Sending packet to %s\n", mac_.str().c_str());
linklayer_out_(std::move(pckt));
}
void Inet::error_report(Error& err, Packet_ptr orig_pckt) {
// if its a forged packet, it might be too small
if (orig_pckt->size() < 40) return;
auto pckt_ip4 = static_unique_ptr_cast<PacketIP4>(std::move(orig_pckt));
// Get the destination to the original packet
const Socket dest =
[] (std::unique_ptr<PacketIP4>& pkt)->Socket
{
// if its a forged packet, it might not be IPv4
if (pkt->is_ipv4() == false) return {};
// switch on IP4 protocol
switch (pkt->ip_protocol()) {
case Protocol::UDP: {
const auto& udp = static_cast<const PacketUDP&>(*pkt);
return udp.destination();
}
case Protocol::TCP: {
auto tcp = tcp::Packet4_view(std::move(pkt));
auto dst = tcp.destination();
pkt = static_unique_ptr_cast<PacketIP4>(tcp.release());
return dst;
}
default:
return {};
}
}(pckt_ip4);
bool too_big = false;
if (err.is_icmp()) {
auto* icmp_err = dynamic_cast<ICMP_error*>(&err);
if (icmp_err == nullptr) {
return; // not an ICMP error
}
if (icmp_err->is_too_big()) {
// If Path MTU Discovery is not enabled, ignore the ICMP Datagram Too Big message
if (not ip4_.path_mtu_discovery())
return;
too_big = true;
// We have received a response to a packet with an MTU that is too big for a node in the path,
// and the packet has been dropped (the original packet was too big and the Don't Fragment bit was set)
// Notify every protocol of the received MTU if any of the protocol's connections use the given
// path (based on destination address)
// Also need to notify the instance that sent the packet that the packet has been dropped, so
// it can retransmit it
// A Destination Unreachable: Fragmentation Needed ICMP error message has been received
// And we'll notify the IP layer of the received MTU value
// IP will create the path if it doesn't exist and only update the value if
// the value is smaller than the already registered pmtu for this path/destination
// If the received MTU value is zero, the method will use the original packet's Total Length
// and Header Length values to estimate a new Path MTU value
ip4_.update_path(dest, icmp_err->pmtu(), too_big, pckt_ip4->ip_total_length(), pckt_ip4->ip_header_length());
// The actual MTU for the path is set in the error object
icmp_err->set_pmtu(ip4_.pmtu(dest));
}
}
if (too_big) {
// Notify both transport layers in case they use the path
udp_.error_report(err, dest);
tcp_.error_report(err, dest);
} else if (pckt_ip4->ip_protocol() == Protocol::UDP) {
udp_.error_report(err, dest);
} else if (pckt_ip4->ip_protocol() == Protocol::TCP) {
tcp_.error_report(err, dest);
}
}
