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Code Issues Releases Wiki Activity

BaseSniffer::next_packet now uses pcap_dispatch.

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This commit is contained in:
Matias Fontanini
2013-09-23 22:55:18 -03:00
parent 2414edd1e7
commit 9cbac6b044
1 changed files with 67 additions and 32 deletions
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99
src/sniffer.cpp
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@@ -56,39 +56,74 @@ void BaseSniffer::init(pcap_t *phandle, const std::string &filter,
throw runtime_error("Invalid filter");
}
PtrPacket BaseSniffer::next_packet() {
pcap_pkthdr header;
PDU *ret = 0;
while(!ret) {
const u_char *content = pcap_next(handle, &header);
const int iface_type = pcap_datalink(handle);
if(content) {
try {
if(iface_type == DLT_EN10MB) {
if(Internals::is_dot3((const uint8_t*)content, header.caplen))
ret = new Dot3((const uint8_t*)content, header.caplen);
else
ret = new EthernetII((const uint8_t*)content, header.caplen);
}
else if(iface_type == DLT_IEEE802_11_RADIO)
ret = new RadioTap((const uint8_t*)content, header.caplen);
else if(iface_type == DLT_IEEE802_11)
ret = Dot11::from_bytes((const uint8_t*)content, header.caplen);
else if(iface_type == DLT_LOOP)
ret = new Tins::Loopback((const uint8_t*)content, header.caplen);
else if(iface_type == DLT_LINUX_SLL)
ret = new Tins::SLL((const uint8_t*)content, header.caplen);
else if(iface_type == DLT_PPI)
ret = new Tins::PPI((const uint8_t*)content, header.caplen);
else
throw unknown_link_type();
}
catch(malformed_packet&) {}
}
else
break;
struct sniff_data {
struct timeval tv;
PDU *pdu;
sniff_data() : pdu(0) { }
};
template<typename T>
T *safe_alloc(const u_char *bytes, bpf_u_int32 len) {
try {
return new T((const uint8_t*)bytes, len);
}
return PtrPacket(ret, header.ts);
catch(malformed_packet&) {
return 0;
}
}
template<typename T>
void sniff_loop_handler(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes) {
sniff_data *data = (sniff_data*)user;
data->tv = h->ts;
data->pdu = safe_alloc<T>(bytes, h->caplen);
}
void sniff_loop_eth_handler(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes) {
sniff_data *data = (sniff_data*)user;
data->tv = h->ts;
if(Internals::is_dot3((const uint8_t*)bytes, h->caplen))
data->pdu = safe_alloc<Dot3>((const uint8_t*)bytes, h->caplen);
else
data->pdu = safe_alloc<EthernetII>((const uint8_t*)bytes, h->caplen);
}
void sniff_loop_dot11_handler(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes) {
sniff_data *data = (sniff_data*)user;
data->tv = h->ts;
try {
data->pdu = Dot11::from_bytes(bytes, h->caplen);
}
catch(malformed_packet&) {
}
}
PtrPacket BaseSniffer::next_packet() {
sniff_data data;
const int iface_type = pcap_datalink(handle);
pcap_handler handler = 0;
if(iface_type == DLT_EN10MB)
handler = sniff_loop_eth_handler;
else if(iface_type == DLT_IEEE802_11_RADIO)
handler = &sniff_loop_handler<RadioTap>;
else if(iface_type == DLT_IEEE802_11)
handler = sniff_loop_dot11_handler;
else if(iface_type == DLT_LOOP)
handler = &sniff_loop_handler<Tins::Loopback>;
else if(iface_type == DLT_LINUX_SLL)
handler = &sniff_loop_handler<SLL>;
else if(iface_type == DLT_PPI)
handler = &sniff_loop_handler<PPI>;
else
throw unknown_link_type();
// keep calling pcap_loop until a well-formed packet is found.
while(data.pdu == 0) {
if(pcap_dispatch(handle, 1, handler, (u_char*)&data) != 1)
return PtrPacket(0, Timestamp());
}
return PtrPacket(data.pdu, data.tv);
}
void BaseSniffer::stop_sniff() {