CaptureReader::CaptureReader(const Params& params) : BaseReader{params.interface}
{
char errbuf[PCAP_ERRBUF_SIZE]; // storage of error description
const char* device {source.c_str()};
handle = pcap_create(device, errbuf);
if(!handle)
{
throw PcapError("pcap_create", errbuf);
}
if(int status {pcap_set_snaplen(handle, params.snaplen)})
{
throw PcapError("pcap_set_snaplen", pcap_statustostr(status));
}
if(int status {pcap_set_promisc(handle, params.promisc ? 1 : 0)})
{
throw PcapError("pcap_set_promisc", pcap_statustostr(status));
}
if(int status {pcap_set_timeout(handle, params.timeout_ms)})
{
throw PcapError("pcap_set_timeout", pcap_statustostr(status));
}
if(int status {pcap_set_buffer_size(handle, params.buffer_size)})
{
throw PcapError("pcap_set_buffer_size", pcap_statustostr(status));
}
if(int status {pcap_activate(handle)})
{
throw PcapError("pcap_activate", pcap_statustostr(status));
}
pcap_direction_t direction {PCAP_D_INOUT};
switch(params.direction)
{
using Direction = CaptureReader::Direction;
case Direction::IN : direction = PCAP_D_IN; break;
case Direction::OUT : direction = PCAP_D_OUT; break;
case Direction::INOUT: direction = PCAP_D_INOUT; break;
}
if(int status {pcap_setdirection(handle, direction)})
{
throw PcapError("pcap_setdirection", pcap_statustostr(status));
}
bpf_u_int32 localnet, netmask;
if(pcap_lookupnet(device, &localnet, &netmask, errbuf) < 0)
{
throw PcapError("pcap_lookupnet", errbuf);
}
BPF bpf(handle, params.filter.c_str(), netmask);
if(pcap_setfilter(handle, bpf) < 0)
{
throw PcapError("pcap_setfiltration", pcap_geterr(handle));
}
}
TCPPacket::TCPPacket(shared_ptr<IPPacket> packet) :
IPPacket(packet) {
if (!isValid(packet)) {
throw PcapError("tcp");
}
this->tcp_header = this->ip_data;
this->tcp_data = this->ip_data + getTCPHeaderLength();
}
void CaptureReader::print_statistic(std::ostream& out) const
{
struct pcap_stat stat={0,0,0};
if(pcap_stats(handle, &stat) == 0)
{
out << "Statistics from interface: " << source << '\n'
<< " packets received by filtration: " << stat.ps_recv << '\n'
<< " packets dropped by kernel : " << stat.ps_drop << '\n'
<< " packets dropped by interface : " << stat.ps_ifdrop;
}
else
{
throw PcapError("pcap_stats", pcap_geterr(handle));
}
}
