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libicsneo/platform/posix/pcap.cpp

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C++
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#include "icsneo/platform/posix/pcap.h"
#include "icsneo/communication/network.h"
#include "icsneo/communication/communication.h"
#include "icsneo/communication/packetizer.h"
#include <codecvt>
#include <chrono>
#include <iostream>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#ifndef __APPLE__
#include <netpacket/packet.h>
#endif
using namespace icsneo;
static const uint8_t BROADCAST_MAC[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
static const uint8_t ICS_UNSET_MAC[6] = { 0x00, 0xFC, 0x70, 0xFF, 0xFF, 0xFF };
std::vector<PCAP::NetworkInterface> PCAP::knownInterfaces;
std::vector<PCAP::PCAPFoundDevice> PCAP::FindAll() {
std::vector<PCAPFoundDevice> foundDevices;
// First we ask WinPCAP to give us all of the devices
pcap_if_t* alldevs;
char errbuf[PCAP_ERRBUF_SIZE] = { 0 };
bool success = false;
// Calling pcap_findalldevs too quickly can cause various errors. Retry a few times in this case.
for(auto retry = 0; retry < 10; retry++) {
auto ret = pcap_findalldevs(&alldevs, errbuf);
if(ret == 0) {
success = true;
break;
}
}
if(!success) {
EventManager::GetInstance().add(APIEvent::Type::PCAPCouldNotFindDevices, APIEvent::Severity::Error);
return std::vector<PCAPFoundDevice>();
}
std::vector<NetworkInterface> interfaces;
for(pcap_if_t* dev = alldevs; dev != nullptr; dev = dev->next) {
if(dev->name == nullptr)
continue;
if(dev->addresses == nullptr) {
//std::cout << dev->name << " has no addresses" << std::endl;
continue;
}
NetworkInterface netif;
netif.nameFromWinPCAP = dev->name;
if(dev->description)
netif.descriptionFromWinPCAP = dev->description;
pcap_addr* currentAddress = dev->addresses;
bool hasAddress = false;
while(!hasAddress && currentAddress != nullptr) {
#ifndef __APPLE__
if(currentAddress->addr && currentAddress->addr->sa_family == AF_PACKET) {
struct sockaddr_ll* s = (struct sockaddr_ll*)currentAddress->addr;
memcpy(netif.macAddress, s->sll_addr, sizeof(netif.macAddress));
hasAddress = true;
break;
}
#else
//TODO: get adapter address on macOS
#endif
currentAddress = currentAddress->next;
}
if(!hasAddress)
continue;
interfaces.push_back(netif);
}
pcap_freealldevs(alldevs);
for(auto& interface : interfaces) {
bool exists = false;
for(auto& known : knownInterfaces)
if(memcmp(interface.macAddress, known.macAddress, sizeof(interface.macAddress)) == 0)
exists = true;
if(!exists)
knownInterfaces.emplace_back(interface);
}
for(size_t i = 0; i < knownInterfaces.size(); i++) {
auto& interface = knownInterfaces[i];
// if(interface.fullName.length() == 0)
// continue; // Win32 did not find this interface in the previous step
errbuf[0] = '\0';
interface.fp = pcap_open_live(interface.nameFromWinPCAP.c_str(), 65536, 1, -1, errbuf);
if(strlen(errbuf) != 0) { // This means a warning
std::cout << "Warning for " << interface.nameFromWinPCAP << " " << errbuf << std::endl;
}
if(interface.fp == nullptr) {
std::cout << "pcap_open_live failed for " << interface.nameFromWinPCAP << " with " << errbuf << std::endl;
continue; // Could not open the interface
}
pcap_setnonblock(interface.fp, 1, errbuf);
EthernetPacket requestPacket;
requestPacket.payload.reserve(4);
requestPacket.payload = {
((1 << 4) | (uint8_t)Network::NetID::Main51), // Packet size of 1 on NETID_MAIN51
(uint8_t)Command::RequestSerialNumber
};
requestPacket.payload.push_back(Packetizer::ICSChecksum(requestPacket.payload));
requestPacket.payload.insert(requestPacket.payload.begin(), 0xAA);
auto bs = requestPacket.getBytestream();
pcap_sendpacket(interface.fp, bs.data(), (int)bs.size());
auto timeout = std::chrono::high_resolution_clock::now() + std::chrono::milliseconds(50);
while(std::chrono::high_resolution_clock::now() <= timeout) { // Wait up to 5ms for the response
struct pcap_pkthdr* header;
const uint8_t* data;
auto res = pcap_next_ex(interface.fp, &header, &data);
if(res < 0) {
std::cout << "pcapnextex failed with " << res << std::endl;
break;
}
if(res == 0)
continue; // Keep waiting for that packet
EthernetPacket packet(data, header->caplen);
// Is this an ICS response packet (0xCAB2) from an ICS MAC, either to broadcast or directly to us?
if(packet.etherType == 0xCAB2 && packet.srcMAC[0] == 0x00 && packet.srcMAC[1] == 0xFC && packet.srcMAC[2] == 0x70 && (
memcmp(packet.destMAC, interface.macAddress, sizeof(packet.destMAC)) == 0 ||
memcmp(packet.destMAC, BROADCAST_MAC, sizeof(packet.destMAC)) == 0 ||
memcmp(packet.destMAC, ICS_UNSET_MAC, sizeof(packet.destMAC)) == 0
)) {
/* We have received a packet from a device. We don't know if this is the device we're
* looking for, we don't know if it's actually a response to our RequestSerialNumber
* or not, we just know we got something.
*
* Unlike most transport layers, we can't get the serial number here as we actually
* need to parse this message that has been returned. Some devices parse messages
* differently, so we need to use their communication layer. We could technically
* create a communication layer to parse the packet we have in `payload` here, but
* we'd need to be given a packetizer and decoder for the device. I'm intentionally
* avoiding passing that information down here for code quality's sake. Instead, pass
* the packet we received back up so the device can handle it.
*/
neodevice_handle_t handle = (neodevice_handle_t)((i << 24) | (packet.srcMAC[3] << 16) | (packet.srcMAC[4] << 8) | (packet.srcMAC[5]));
PCAPFoundDevice* alreadyExists = nullptr;
for(auto& dev : foundDevices)
if(dev.device.handle == handle)
alreadyExists = &dev;
if(alreadyExists == nullptr) {
PCAPFoundDevice foundDevice;
foundDevice.device.handle = handle;
foundDevice.discoveryPackets.push_back(std::move(packet.payload));
foundDevices.push_back(foundDevice);
} else {
alreadyExists->discoveryPackets.push_back(std::move(packet.payload));
}
}
}
pcap_close(interface.fp);
interface.fp = nullptr;
}
return foundDevices;
}
bool PCAP::IsHandleValid(neodevice_handle_t handle) {
uint8_t netifIndex = (uint8_t)(handle >> 24);
return (netifIndex < knownInterfaces.size());
}
PCAP::PCAP(device_eventhandler_t err, neodevice_t& forDevice) : Driver(err), device(forDevice) {
if(IsHandleValid(device.handle)) {
interface = knownInterfaces[(device.handle >> 24) & 0xFF];
interface.fp = nullptr; // We're going to open our own connection to the interface. This should already be nullptr but just in case.
deviceMAC[0] = 0x00;
deviceMAC[1] = 0xFC;
deviceMAC[2] = 0x70;
deviceMAC[3] = (device.handle >> 16) & 0xFF;
deviceMAC[4] = (device.handle >> 8) & 0xFF;
deviceMAC[5] = device.handle & 0xFF;
} else {
openable = false;
}
}
bool PCAP::open() {
if(!openable)
return false;
if(isOpen())
return false;
// Open the interface
interface.fp = pcap_open_live(interface.nameFromWinPCAP.c_str(), 65536, 1, -1, errbuf);
if(interface.fp == nullptr) {
report(APIEvent::Type::DriverFailedToOpen, APIEvent::Severity::Error);
return false;
}
pcap_setnonblock(interface.fp, 1, errbuf);
// Create threads
readThread = std::thread(&PCAP::readTask, this);
writeThread = std::thread(&PCAP::writeTask, this);
return true;
}
bool PCAP::isOpen() {
return interface.fp != nullptr;
}
bool PCAP::close() {
if(!isOpen())
return false;
closing = true; // Signal the threads that we are closing
readThread.join();
writeThread.join();
closing = false;
pcap_close(interface.fp);
interface.fp = nullptr;
uint8_t flush;
WriteOperation flushop;
while(readQueue.try_dequeue(flush)) {}
while(writeQueue.try_dequeue(flushop)) {}
return true;
}
void PCAP::readTask() {
struct pcap_pkthdr* header;
const uint8_t* data;
EventManager::GetInstance().downgradeErrorsOnCurrentThread();
while(!closing) {
auto readBytes = pcap_next_ex(interface.fp, &header, &data);
if(readBytes < 0) {
report(APIEvent::Type::FailedToRead, APIEvent::Severity::Error);
break;
}
if(readBytes == 0)
continue; // Keep waiting for that packet
EthernetPacket packet(data, header->caplen);
if(packet.etherType != 0xCAB2)
continue; // Not a packet to host
if(memcmp(packet.destMAC, interface.macAddress, sizeof(packet.destMAC)) != 0 &&
memcmp(packet.destMAC, BROADCAST_MAC, sizeof(packet.destMAC)) != 0 &&
memcmp(packet.destMAC, ICS_UNSET_MAC, sizeof(packet.destMAC)) != 0)
continue; // Packet is not addressed to us or broadcast
if(memcmp(packet.srcMAC, deviceMAC, sizeof(deviceMAC)) != 0)
continue; // Not a packet from the device we're concerned with
readQueue.enqueue_bulk(packet.payload.data(), packet.payload.size());
}
}
void PCAP::writeTask() {
WriteOperation writeOp;
uint16_t sequence = 0;
EthernetPacket sendPacket;
EventManager::GetInstance().downgradeErrorsOnCurrentThread();
// Set MAC address of packet
memcpy(sendPacket.srcMAC, interface.macAddress, sizeof(sendPacket.srcMAC));
memcpy(sendPacket.destMAC, deviceMAC, sizeof(deviceMAC));
while(!closing) {
if(!writeQueue.wait_dequeue_timed(writeOp, std::chrono::milliseconds(100)))
continue;
sendPacket.packetNumber = sequence++;
sendPacket.payload = std::move(writeOp.bytes);
auto bs = sendPacket.getBytestream();
if(!closing)
pcap_sendpacket(interface.fp, bs.data(), (int)bs.size());
// TODO Handle packet send errors
}
}
PCAP::EthernetPacket::EthernetPacket(const std::vector<uint8_t>& bytestream) {
loadBytestream(bytestream);
}
PCAP::EthernetPacket::EthernetPacket(const uint8_t* data, size_t size) {
std::vector<uint8_t> bs(size);
for(size_t i = 0; i < size; i++)
bs[i] = data[i];
loadBytestream(bs);
}
int PCAP::EthernetPacket::loadBytestream(const std::vector<uint8_t>& bytestream) {
errorWhileDecodingFromBytestream = 0;
for(size_t i = 0; i < 6; i++)
destMAC[i] = bytestream[i];
for(size_t i = 0; i < 6; i++)
srcMAC[i] = bytestream[i + 6];
etherType = (bytestream[12] << 8) | bytestream[13];
icsEthernetHeader = (bytestream[14] << 24) | (bytestream[15] << 16) | (bytestream[16] << 8) | bytestream[17];
uint16_t payloadSize = bytestream[18] | (bytestream[19] << 8);
packetNumber = bytestream[20] | (bytestream[21] << 8);
uint16_t packetInfo = bytestream[22] | (bytestream[23] << 8);
firstPiece = packetInfo & 1;
lastPiece = (packetInfo >> 1) & 1;
bufferHalfFull = (packetInfo >> 2) & 2;
payload = std::vector<uint8_t>(bytestream.begin() + 24, bytestream.end());
size_t payloadActualSize = payload.size();
if(payloadActualSize < payloadSize)
errorWhileDecodingFromBytestream = 1;
payload.resize(payloadSize);
return errorWhileDecodingFromBytestream;
}
std::vector<uint8_t> PCAP::EthernetPacket::getBytestream() const {
size_t payloadSize = payload.size();
std::vector<uint8_t> bytestream;
bytestream.reserve(6 + 6 + 2 + 4 + 2 + 2 + 2 + payloadSize);
for(size_t i = 0; i < 6; i++)
bytestream.push_back(destMAC[i]);
for(size_t i = 0; i < 6; i++)
bytestream.push_back(srcMAC[i]);
// EtherType should be put into the bytestream as big endian
bytestream.push_back((uint8_t)(etherType >> 8));
bytestream.push_back((uint8_t)(etherType));
// Our Ethernet header should be put into the bytestream as big endian
bytestream.push_back((uint8_t)(icsEthernetHeader >> 24));
bytestream.push_back((uint8_t)(icsEthernetHeader >> 16));
bytestream.push_back((uint8_t)(icsEthernetHeader >> 8));
bytestream.push_back((uint8_t)(icsEthernetHeader));
// The payload size comes next, it's little endian
bytestream.push_back((uint8_t)(payloadSize));
bytestream.push_back((uint8_t)(payloadSize >> 8));
// Packet number is little endian
bytestream.push_back((uint8_t)(packetNumber));
bytestream.push_back((uint8_t)(packetNumber >> 8));
// Packet info gets assembled into a bitfield
uint16_t packetInfo = 0;
packetInfo |= firstPiece & 1;
packetInfo |= (lastPiece & 1) << 1;
packetInfo |= (bufferHalfFull & 1) << 2;
bytestream.push_back((uint8_t)(packetInfo));
bytestream.push_back((uint8_t)(packetInfo >> 8));
bytestream.insert(bytestream.end(), payload.begin(), payload.end());
return bytestream;
}
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