forked from node-pcap/node_pcap
-
Notifications
You must be signed in to change notification settings - Fork 0
/
pcap_binding.cc
334 lines (267 loc) · 11 KB
/
pcap_binding.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
#include <node.h>
#include <node_events.h>
#include <node_buffer.h>
#include <assert.h>
#include <pcap/pcap.h>
#include <v8.h>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ev.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
using namespace v8;
using namespace node;
// These things need to be moved into a class, so each instance can have its own session.
// Right now, there can only be one pcap session at a time.
struct bpf_program fp;
bpf_u_int32 mask;
bpf_u_int32 net;
pcap_t *pcap_handle;
Buffer *buffer;
// PacketReady is called from within pcap, still on the stack of Dispatch. It should be called
// only one time per Dispatch, but sometimes it gets called 0 times. PacketReady invokes the
// JS callback associated with the dispatch() call in JS.
//
// Stack:
// 1. readWatcher.callback (pcap.js)
// 2. binding.dispatch (pcap.js)
// 3. Dispatch (binding.cc)
// 4. pcap_dispatch (libpcap)
// 5. PacketReady (binding.cc)
// 6. binding.dispatch callback (pcap.js)
//
void PacketReady(u_char *callback_p, const struct pcap_pkthdr* pkthdr, const u_char* packet) {
HandleScope scope;
Local<Function> * callback = (Local<Function>*)callback_p;
// TODO - bounds checking
memcpy(buffer->data(), packet, pkthdr->caplen);
TryCatch try_catch;
Local<Object> packet_header = Object::New();
packet_header->Set(String::New("tv_sec"), Integer::NewFromUnsigned(pkthdr->ts.tv_sec));
packet_header->Set(String::New("tv_usec"), Integer::NewFromUnsigned(pkthdr->ts.tv_usec));
packet_header->Set(String::New("caplen"), Integer::NewFromUnsigned(pkthdr->caplen));
packet_header->Set(String::New("len"), Integer::NewFromUnsigned(pkthdr->len));
Local<Value> argv[1] = { packet_header };
(*callback)->Call(Context::GetCurrent()->Global(), 1, argv);
if (try_catch.HasCaught()) {
FatalException(try_catch);
}
}
Handle<Value>
Dispatch(const Arguments& args)
{
HandleScope scope;
if (args.Length() != 2) {
return ThrowException(Exception::TypeError(String::New("Dispatch takes exactly two arguments")));
}
if (!Buffer::HasInstance(args[0])) {
return ThrowException(Exception::TypeError(String::New("First argument must be a buffer")));
}
if (!args[1]->IsFunction()) {
return ThrowException(Exception::TypeError(String::New("Second argument must be a function")));
}
Local<Function> callback = Local<Function>::Cast(args[1]);
buffer = ObjectWrap::Unwrap<Buffer>(args[0]->ToObject());
int packet_count, total_packets = 0;
do {
packet_count = pcap_dispatch(pcap_handle, 1, PacketReady, (u_char *)&callback);
total_packets += packet_count;
} while (packet_count > 0);
return scope.Close(Integer::NewFromUnsigned(total_packets));
}
Handle<Value>
OpenLive(const Arguments& args)
{
HandleScope scope;
char errbuf[PCAP_ERRBUF_SIZE];
if (args.Length() != 2 || !args[0]->IsString() || !args[1]->IsString()) {
return ThrowException(Exception::TypeError(String::New("Bad arguments")));
}
String::Utf8Value device(args[0]->ToString());
String::Utf8Value filter(args[1]->ToString());
// TODO - check for empty device string and look up default device
if (pcap_lookupnet((char *) *device, &net, &mask, errbuf) == -1) {
net = 0;
mask = 0;
fprintf(stderr, "warning: %s - filtering may not work right\n", errbuf);
}
pcap_handle = pcap_create((char *) *device, errbuf);
if (pcap_handle == NULL) {
return ThrowException(Exception::Error(String::New(errbuf)));
}
// 64KB is the max IPv4 packet size
if (pcap_set_snaplen(pcap_handle, 65535) != 0) {
return ThrowException(Exception::Error(String::New("error setting snaplen")));
}
// always use promiscuous mode
if (pcap_set_promisc(pcap_handle, 1) != 0) {
return ThrowException(Exception::Error(String::New("error setting promiscuous mode")));
}
// Try to set a 10MB buffer size. Sometimes the OS has a lower limit that it will silently enforce.
// TODO - make this settable at runtime
if (pcap_set_buffer_size(pcap_handle, 10 * 1024 * 1024) != 0) {
return ThrowException(Exception::Error(String::New("error setting buffer size")));
}
// set "timeout" on read, even though we are also setting nonblock below. On Linux this is required.
if (pcap_set_timeout(pcap_handle, 1000) != 0) {
return ThrowException(Exception::Error(String::New("error setting read timeout")));
}
// TODO - pass in an option to enable rfmon on supported interfaces. Sadly, it can be a disruptive
// operation, so we can't just always try to turn it on.
// if (pcap_set_rfmon(pcap_handle, 1) != 0) {
// return ThrowException(Exception::Error(String::New(pcap_geterr(pcap_handle))));
// }
if (pcap_activate(pcap_handle) != 0) {
return ThrowException(Exception::Error(String::New(pcap_geterr(pcap_handle))));
}
if (pcap_setnonblock(pcap_handle, 1, errbuf) == -1) {
return ThrowException(Exception::Error(String::New(errbuf)));
}
// TODO - if filter is empty, don't bother with compile or set
if (pcap_compile(pcap_handle, &fp, (char *) *filter, 1, net) == -1) {
return ThrowException(Exception::Error(String::New(pcap_geterr(pcap_handle))));
}
if (pcap_setfilter(pcap_handle, &fp) == -1) {
return ThrowException(Exception::Error(String::New(pcap_geterr(pcap_handle))));
}
// Work around buffering bug in BPF on OSX 10.6 as of May 19, 2010
// This may result in dropped packets under load because it disables the (broken) buffer
// http://seclists.org/tcpdump/2010/q1/110
#if defined(__APPLE_CC__) || defined(__APPLE__)
#include <net/bpf.h>
int fd = pcap_get_selectable_fd(pcap_handle);
int v = 1;
ioctl(fd, BIOCIMMEDIATE, &v);
// TODO - check return value
#endif
int link_type = pcap_datalink(pcap_handle);
Local<Value> ret;
switch (link_type) {
case DLT_NULL:
ret = String::New("LINKTYPE_NULL");
break;
case DLT_EN10MB: // most wifi interfaces pretend to be "ethernet"
ret = String::New("LINKTYPE_ETHERNET");
break;
case DLT_IEEE802_11_RADIO: // 802.11 "monitor mode"
ret = String::New("LINKTYPE_IEEE802_11_RADIO");
break;
default:
snprintf(errbuf, PCAP_ERRBUF_SIZE, "Unknown linktype %d", link_type);
ret = String::New(errbuf);
break;
}
return scope.Close(ret);
}
Handle<Value>
FindAllDevs(const Arguments& args)
{
HandleScope scope;
char errbuf[PCAP_ERRBUF_SIZE];
pcap_if_t *alldevsp, *cur_dev;
if (pcap_findalldevs(&alldevsp, errbuf) == -1) {
return ThrowException(Exception::TypeError(String::New(errbuf)));
}
Local<Array> DevsArray = Array::New();
int i = 0;
for (cur_dev = alldevsp ; cur_dev != NULL ; cur_dev = cur_dev->next, i++) {
Local<Object> Dev = Object::New();
Dev->Set(String::New("name"), String::New(cur_dev->name));
if (cur_dev->description != NULL) {
Dev->Set(String::New("description"), String::New(cur_dev->description));
}
Local<Array> AddrArray = Array::New();
int j = 0;
for (pcap_addr_t *cur_addr = cur_dev->addresses ; cur_addr != NULL ; cur_addr = cur_addr->next, j++) {
if (cur_addr->addr->sa_family == AF_INET) {
Local<Object> Address = Object::New();
struct sockaddr_in *sin = (struct sockaddr_in *) cur_addr->addr;
Address->Set(String::New("addr"), String::New(inet_ntoa(sin->sin_addr)));
if (cur_addr->netmask != NULL) {
sin = (struct sockaddr_in *) cur_addr->netmask;
Address->Set(String::New("netmask"), String::New(inet_ntoa(sin->sin_addr)));
}
if (cur_addr->broadaddr != NULL) {
sin = (struct sockaddr_in *) cur_addr->broadaddr;
Address->Set(String::New("broadaddr"), String::New(inet_ntoa(sin->sin_addr)));
}
if (cur_addr->dstaddr != NULL) {
sin = (struct sockaddr_in *) cur_addr->dstaddr;
Address->Set(String::New("dstaddr"), String::New(inet_ntoa(sin->sin_addr)));
}
AddrArray->Set(Integer::New(j), Address);
}
// TODO - support AF_INET6
}
Dev->Set(String::New("addresses"), AddrArray);
if (cur_dev->flags & PCAP_IF_LOOPBACK) {
Dev->Set(String::New("flags"), String::New("PCAP_IF_LOOPBACK"));
}
DevsArray->Set(Integer::New(i), Dev);
}
pcap_freealldevs(alldevsp);
return scope.Close(DevsArray);
}
Handle<Value>
Close(const Arguments& args)
{
HandleScope scope;
pcap_close(pcap_handle);
return Undefined();
}
Handle<Value>
Fileno(const Arguments& args)
{
HandleScope scope;
int fd = pcap_get_selectable_fd(pcap_handle);
return scope.Close(Integer::NewFromUnsigned(fd));
}
Handle<Value>
Stats(const Arguments& args)
{
HandleScope scope;
struct pcap_stat ps;
if (pcap_stats(pcap_handle, &ps) == -1) {
return ThrowException(Exception::Error(String::New("Error in pcap_stats")));
// TODO - use pcap_geterr to figure out what the error was
}
Local<Object> stats_obj = Object::New();
stats_obj->Set(String::New("ps_recv"), Integer::NewFromUnsigned(ps.ps_recv));
stats_obj->Set(String::New("ps_drop"), Integer::NewFromUnsigned(ps.ps_drop));
stats_obj->Set(String::New("ps_ifdrop"), Integer::NewFromUnsigned(ps.ps_ifdrop));
// ps_ifdrop may not be supported on this platform, but there's no good way to tell
return scope.Close(stats_obj);
}
Handle<Value>
DefaultDevice(const Arguments& args)
{
HandleScope scope;
char *dev, errbuf[PCAP_ERRBUF_SIZE];
dev = pcap_lookupdev(errbuf);
if (dev == NULL) {
return ThrowException(Exception::Error(String::New(errbuf)));
}
return scope.Close(String::New(dev));
}
Handle<Value>
LibVersion(const Arguments &args)
{
HandleScope scope;
return scope.Close(String::New(pcap_lib_version()));
}
extern "C" void init (Handle<Object> target)
{
HandleScope scope;
target->Set(String::New("findalldevs"), FunctionTemplate::New(FindAllDevs)->GetFunction());
target->Set(String::New("open_live"), FunctionTemplate::New(OpenLive)->GetFunction());
target->Set(String::New("dispatch"), FunctionTemplate::New(Dispatch)->GetFunction());
target->Set(String::New("fileno"), FunctionTemplate::New(Fileno)->GetFunction());
target->Set(String::New("close"), FunctionTemplate::New(Close)->GetFunction());
target->Set(String::New("stats"), FunctionTemplate::New(Stats)->GetFunction());
target->Set(String::New("default_device"), FunctionTemplate::New(DefaultDevice)->GetFunction());
target->Set(String::New("lib_version"), FunctionTemplate::New(LibVersion)->GetFunction());
}