void pcap_callback(evutil_socket_t fd, short what, void *arg) {
struct module* mod = (struct module*) arg;
struct pcap_pkthdr pkthdr;
const unsigned char *packet = NULL;
while ((packet = pcap_next(mod->pcap_handle, &pkthdr)) != NULL) {
dispatchDatabases();
if (mod->rawpacket_callback)
mod->rawpacket_callback(packet, pkthdr, mod->context);
struct ethernet_header* ethernet_header = NULL;
struct ipv4_header* ipv4 = NULL;
if (mod->ipv4_callback) {
ethernet_header = getEthernetHeader(packet);
ipv4 = getIPv4Header(packet);
if (ethernet_header && ipv4)
mod->ipv4_callback(ethernet_header, ipv4, packet, pkthdr, mod->context);
}
if (mod->ipv4_udp_callback) {
if (!ethernet_header)
ethernet_header = getEthernetHeader(packet);
if (!ipv4)
ipv4 = getIPv4Header(packet);
if (ethernet_header && ipv4) {
struct udp_header* udp = getUDPHeaderFromIPv4(packet, ipv4);
if (udp)
mod->ipv4_udp_callback(ethernet_header, ipv4, udp, packet, pkthdr, mod->context);
}
}
}
};
void IPv4Layer::computeCalculateFields()
{
iphdr* ipHdr = getIPv4Header();
ipHdr->internetHeaderLength = (5 & 0xf);
ipHdr->ipVersion = (4 & 0x0f);
ipHdr->totalLength = htons(m_DataLen);
ipHdr->headerChecksum = 0;
if (m_NextLayer != NULL)
{
switch (m_NextLayer->getProtocol())
{
case TCP:
ipHdr->protocol = PACKETPP_IPPROTO_TCP;
break;
case UDP:
ipHdr->protocol = PACKETPP_IPPROTO_UDP;
break;
case ICMP:
ipHdr->protocol = PACKETPP_IPPROTO_ICMP;
break;
default:
break;
}
}
ScalarBuffer scalar = { (uint16_t*)ipHdr, ipHdr->internetHeaderLength*4 } ;
ipHdr->headerChecksum = htons(compute_checksum(&scalar, 1));
}
IPv4Layer::IPv4Layer(const IPv4Address& srcIP, const IPv4Address& dstIP)
{
initLayer();
iphdr* ipHdr = getIPv4Header();
ipHdr->ipSrc = srcIP.toInt();
ipHdr->ipDst = dstIP.toInt();
}
void IPv4Layer::parseNextLayer()
{
if (m_DataLen <= sizeof(iphdr))
return;
iphdr* ipHdr = getIPv4Header();
switch (ipHdr->protocol)
{
case PACKETPP_IPPROTO_UDP:
m_NextLayer = new UdpLayer(m_Data + sizeof(iphdr), m_DataLen - sizeof(iphdr), this, m_Packet);
break;
case PACKETPP_IPPROTO_TCP:
m_NextLayer = new TcpLayer(m_Data + sizeof(iphdr), m_DataLen - sizeof(iphdr), this, m_Packet);
break;
default:
m_NextLayer = new PayloadLayer(m_Data + sizeof(iphdr), m_DataLen - sizeof(iphdr), this, m_Packet);
return;
}
}
