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Files
libtins/src/sniffer.cpp
2012-09-06 00:37:12 -03:00

116 lines
3.3 KiB
C++

/*
* libtins is a net packet wrapper library for crafting and
* interpreting sniffed packets.
*
* Copyright (C) 2011 Nasel
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "sniffer.h"
using std::string;
using std::runtime_error;
namespace Tins {
BaseSniffer::BaseSniffer() : handle(0), mask(0)
{
actual_filter.bf_insns = 0;
}
BaseSniffer::~BaseSniffer() {
if(actual_filter.bf_insns)
pcap_freecode(&actual_filter);
if(handle)
pcap_close(handle);
}
void BaseSniffer::init(pcap_t *phandle, const std::string &filter,
bpf_u_int32 if_mask)
{
handle = phandle;
mask = if_mask;
wired = (pcap_datalink(handle) != DLT_IEEE802_11_RADIO); //better plx
actual_filter.bf_insns = 0;
if(!filter.empty() && !set_filter(filter))
throw runtime_error("Invalid filter");
}
bool BaseSniffer::compile_set_filter(const string &filter, bpf_program &prog) {
return (pcap_compile(handle, &prog, filter.c_str(), 0, mask) != -1 && pcap_setfilter(handle, &prog) != -1);
}
PDU *BaseSniffer::next_packet() {
pcap_pkthdr header;
PDU *ret = 0;
while(!ret) {
const u_char *content = pcap_next(handle, &header);
if(content) {
try {
if(wired)
ret = new EthernetII((const uint8_t*)content, header.caplen);
else
ret = new RadioTap((const uint8_t*)content, header.caplen);
}
catch(...) {
ret = 0;
}
}
}
return ret;
}
void BaseSniffer::stop_sniff() {
pcap_breakloop(handle);
}
bool BaseSniffer::set_filter(const std::string &filter) {
if(actual_filter.bf_insns)
pcap_freecode(&actual_filter);
return compile_set_filter(filter, actual_filter);
}
// ****************************** Sniffer ******************************
Sniffer::Sniffer(const string &device, unsigned max_packet_size,
bool promisc, const string &filter)
{
char error[PCAP_ERRBUF_SIZE];
bpf_u_int32 ip, if_mask;
if (pcap_lookupnet(device.c_str(), &ip, &if_mask, error) == -1) {
ip = 0;
if_mask = 0;
}
pcap_t *phandle = pcap_open_live(device.c_str(), max_packet_size, promisc, 0, error);
if(!phandle)
throw runtime_error(error);
init(phandle, filter, if_mask);
}
// **************************** FileSniffer ****************************
FileSniffer::FileSniffer(const string &file_name, const string &filter) {
char error[PCAP_ERRBUF_SIZE];
pcap_t *phandle = pcap_open_offline(file_name.c_str(), error);
if(!phandle)
throw std::runtime_error(error);
init(phandle, filter, 0);
}
}