summaryrefslogtreecommitdiff
path: root/tools/sniffer.cpp
blob: 9590d8fc8e9419982121a19b39cc180b165dc4e9 (plain)
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
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
// sniffer.cpp

/*
  TODO:
    large messages - need to track what's left and ingore
    single object over packet size - can only display begging of object

    getmore
    delete
    killcursors

 */

#include <pcap.h>

#ifdef _WIN32
#undef min
#undef max
#endif

#include "../util/builder.h"
#include "../util/message.h"
#include "../db/dbmessage.h"
#include "../client/dbclient.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <sys/types.h>
#ifndef _WIN32
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#endif

#include <iostream>
#include <map>
#include <string>

#include <boost/shared_ptr.hpp>

using namespace std;
using mongo::asserted;
using mongo::Message;
using mongo::MsgData;
using mongo::DbMessage;
using mongo::BSONObj;
using mongo::BufBuilder;
using mongo::DBClientConnection;
using mongo::QueryResult;

#define SNAP_LEN 65535

int captureHeaderSize;
set<int> serverPorts;
string forwardAddress;

/* IP header */
struct sniff_ip {
    u_char  ip_vhl;                 /* version << 4 | header length >> 2 */
    u_char  ip_tos;                 /* type of service */
    u_short ip_len;                 /* total length */
    u_short ip_id;                  /* identification */
    u_short ip_off;                 /* fragment offset field */
#define IP_RF 0x8000            /* reserved fragment flag */
#define IP_DF 0x4000            /* dont fragment flag */
#define IP_MF 0x2000            /* more fragments flag */
#define IP_OFFMASK 0x1fff       /* mask for fragmenting bits */
    u_char  ip_ttl;                 /* time to live */
    u_char  ip_p;                   /* protocol */
    u_short ip_sum;                 /* checksum */
    struct  in_addr ip_src,ip_dst;  /* source and dest address */
};
#define IP_HL(ip)               (((ip)->ip_vhl) & 0x0f)
#define IP_V(ip)                (((ip)->ip_vhl) >> 4)

/* TCP header */
typedef u_int32_t tcp_seq;

struct sniff_tcp {
    u_short th_sport;               /* source port */
    u_short th_dport;               /* destination port */
    tcp_seq th_seq;                 /* sequence number */
    tcp_seq th_ack;                 /* acknowledgement number */
    u_char  th_offx2;               /* data offset, rsvd */
#define TH_OFF(th)      (((th)->th_offx2 & 0xf0) >> 4)
    u_char  th_flags;
#define TH_FIN  0x01
#define TH_SYN  0x02
#define TH_RST  0x04
#define TH_PUSH 0x08
#define TH_ACK  0x10
#define TH_URG  0x20
#define TH_ECE  0x40
#define TH_CWR  0x80

#ifndef TH_FLAGS
#define TH_FLAGS        (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
#endif

    u_short th_win;                 /* window */
    u_short th_sum;                 /* checksum */
    u_short th_urp;                 /* urgent pointer */
};

#pragma pack( 1 )
struct Connection {
    struct in_addr srcAddr;
    u_short srcPort;
    struct in_addr dstAddr;
    u_short dstPort;
    bool operator<( const Connection &other ) const {
        return memcmp( this, &other, sizeof( Connection ) ) < 0;
    }
    Connection reverse() const {
        Connection c;
        c.srcAddr = dstAddr;
        c.srcPort = dstPort;
        c.dstAddr = srcAddr;
        c.dstPort = srcPort;
        return c;
    }
};
#pragma pack()

map< Connection, bool > seen;
map< Connection, int > bytesRemainingInMessage;
map< Connection, boost::shared_ptr< BufBuilder > > messageBuilder;
map< Connection, unsigned > expectedSeq;
map< Connection, DBClientConnection* > forwarder;
map< Connection, long long > lastCursor;
map< Connection, map< long long, long long > > mapCursor;

void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet){

    const struct sniff_ip* ip = (struct sniff_ip*)(packet + captureHeaderSize);
    int size_ip = IP_HL(ip)*4;
    if ( size_ip < 20 ){
        cerr << "*** Invalid IP header length: " << size_ip << " bytes" << endl;
        return;
    }

    assert( ip->ip_p == IPPROTO_TCP );

    const struct sniff_tcp* tcp = (struct sniff_tcp*)(packet + captureHeaderSize + size_ip);
    int size_tcp = TH_OFF(tcp)*4;
    if (size_tcp < 20){
        cerr << "*** Invalid TCP header length: " << size_tcp << " bytes" << endl;
        return;
    }

    if ( ! ( serverPorts.count( ntohs( tcp->th_sport ) ) ||
             serverPorts.count( ntohs( tcp->th_dport ) ) ) ){
        return;
    }

    const u_char * payload = (const u_char*)(packet + captureHeaderSize + size_ip + size_tcp);

    unsigned totalSize = ntohs(ip->ip_len);
    assert( totalSize <= header->caplen );

    int size_payload = totalSize - (size_ip + size_tcp);
    if (size_payload <= 0 )
        return;

    Connection c;
    c.srcAddr = ip->ip_src;
    c.srcPort = tcp->th_sport;
    c.dstAddr = ip->ip_dst;
    c.dstPort = tcp->th_dport;

    if ( seen[ c ] ) {
        if ( expectedSeq[ c ] != ntohl( tcp->th_seq ) ) {
            cerr << "Warning: sequence # mismatch, there may be dropped packets" << endl;
        }
    } else {
        seen[ c ] = true;
    }

    expectedSeq[ c ] = ntohl( tcp->th_seq ) + size_payload;

    Message m;

    if ( bytesRemainingInMessage[ c ] == 0 ) {
        m.setData( (MsgData*)payload , false );
        if ( !m.data->valid() ) {
            cerr << "Invalid message start, skipping packet." << endl;
            return;
        }
        if ( size_payload > m.data->len ) {
            cerr << "Multiple messages in packet, skipping packet." << endl;
            return;
        }
        if ( size_payload < m.data->len ) {
            bytesRemainingInMessage[ c ] = m.data->len - size_payload;
            messageBuilder[ c ].reset( new BufBuilder() );
            messageBuilder[ c ]->append( (void*)payload, size_payload );
            return;
        }
    } else {
        bytesRemainingInMessage[ c ] -= size_payload;
        messageBuilder[ c ]->append( (void*)payload, size_payload );
        if ( bytesRemainingInMessage[ c ] < 0 ) {
            cerr << "Received too many bytes to complete message, resetting buffer" << endl;
            bytesRemainingInMessage[ c ] = 0;
            messageBuilder[ c ].reset();
            return;
        }
        if ( bytesRemainingInMessage[ c ] > 0 )
            return;
        m.setData( (MsgData*)messageBuilder[ c ]->buf(), true );
        messageBuilder[ c ]->decouple();
        messageBuilder[ c ].reset();
    }

    DbMessage d( m );

    cout << inet_ntoa(ip->ip_src) << ":" << ntohs( tcp->th_sport )
         << ( serverPorts.count( ntohs( tcp->th_dport ) ) ? "  -->> " : "  <<--  " )
         << inet_ntoa(ip->ip_dst) << ":" << ntohs( tcp->th_dport )
         << " " << d.getns()
         << "  " << m.data->len << " bytes "
         << " id:" << hex << m.data->id << dec << "\t" << m.data->id;

    if ( m.data->operation() == mongo::opReply )
        cout << " - " << m.data->responseTo;
    cout << endl;

    switch( m.data->operation() ){
    case mongo::opReply:{
        mongo::QueryResult* r = (mongo::QueryResult*)m.data;
        cout << "\treply" << " n:" << r->nReturned << " cursorId: " << r->cursorId << endl;
        if ( r->nReturned ){
            mongo::BSONObj o( r->data() , 0 );
            cout << "\t" << o << endl;
        }
        break;
    }
    case mongo::dbQuery:{
        mongo::QueryMessage q(d);
        cout << "\tquery: " << q.query << "  ntoreturn: " << q.ntoreturn << " ntoskip: " << q.ntoskip << endl;
        break;
    }
    case mongo::dbUpdate:{
        int flags = d.pullInt();
        BSONObj q = d.nextJsObj();
        BSONObj o = d.nextJsObj();
        cout << "\tupdate  flags:" << flags << " q:" << q << " o:" << o << endl;
        break;
    }
    case mongo::dbInsert:{
        cout << "\tinsert: " << d.nextJsObj() << endl;
        while ( d.moreJSObjs() )
            cout << "\t\t" << d.nextJsObj() << endl;
        break;
    }
    case mongo::dbGetMore:{
        int nToReturn = d.pullInt();
        long long cursorId = d.pullInt64();
        cout << "\tgetMore nToReturn: " << nToReturn << " cursorId: " << cursorId << endl;
        break;
    }
    case mongo::dbDelete:{
        int flags = d.pullInt();
        BSONObj q = d.nextJsObj();
        cout << "\tdelete flags: " << flags << " q: " << q << endl;
        break;
    }
    case mongo::dbKillCursors:{
        int *x = (int *) m.data->_data;
        x++; // reserved
        int n = *x;
        cout << "\tkillCursors n: " << n << endl;
        break;
    }
    default:
        cerr << "*** CANNOT HANDLE TYPE: " << m.data->operation() << endl;
    }

    if ( !forwardAddress.empty() ) {
        if ( m.data->operation() != mongo::opReply ) {
            DBClientConnection *conn = forwarder[ c ];
            if ( !conn ) {
                // These won't get freed on error, oh well hopefully we'll just
                // abort in that case anyway.
                conn = new DBClientConnection( true );
                conn->connect( forwardAddress );
                forwarder[ c ] = conn;
            }
            if ( m.data->operation() == mongo::dbQuery || m.data->operation() == mongo::dbGetMore ) {
                if ( m.data->operation() == mongo::dbGetMore ) {
                    DbMessage d( m );
                    d.pullInt();
                    long long &cId = d.pullInt64();
                    cId = mapCursor[ c ][ cId ];
                }
                Message response;
                conn->port().call( m, response );
                QueryResult *qr = (QueryResult *) response.data;
                if ( !( qr->resultFlags() & QueryResult::ResultFlag_CursorNotFound ) ) {
                    if ( qr->cursorId != 0 ) {
                        lastCursor[ c ] = qr->cursorId;
                        return;
                    }
                }
                lastCursor[ c ] = 0;
            } else {
                conn->port().say( m );
            }
        } else {
            Connection r = c.reverse();
            long long myCursor = lastCursor[ r ];
            QueryResult *qr = (QueryResult *) m.data;
            long long yourCursor = qr->cursorId;
            if ( ( qr->resultFlags() & QueryResult::ResultFlag_CursorNotFound ) )
                yourCursor = 0;
            if ( myCursor && !yourCursor )
                cerr << "Expected valid cursor in sniffed response, found none" << endl;
            if ( !myCursor && yourCursor )
                cerr << "Sniffed valid cursor when none expected" << endl;
            if ( myCursor && yourCursor ) {
                mapCursor[ r ][ qr->cursorId ] = lastCursor[ r ];
                lastCursor[ r ] = 0;
            }
        }
    }
}

void usage() {
    cout <<
    "Usage: mongosniff [--help] [--forward host:port] [--source (NET <interface> | FILE <filename>)] [<port0> <port1> ... ]\n"
    "--forward       Forward all parsed request messages to mongod instance at \n"
    "                specified host:port\n"
    "--source        Source of traffic to sniff, either a network interface or a\n"
    "                file containing perviously captured packets, in pcap format.\n"
    "                If no source is specified, mongosniff will attempt to sniff\n"
    "                from one of the machine's network interfaces.\n"
    "<port0>...      These parameters are used to filter sniffing.  By default, \n"
    "                only port 27017 is sniffed.\n"
    "--help          Print this help message.\n"
    << endl;
}

int main(int argc, char **argv){

    const char *dev = NULL;
    char errbuf[PCAP_ERRBUF_SIZE];
    pcap_t *handle;

    struct bpf_program fp;
    bpf_u_int32 mask;
    bpf_u_int32 net;

    bool source = false;
    bool replay = false;
    const char *file = 0;

    vector< const char * > args;
    for( int i = 1; i < argc; ++i )
        args.push_back( argv[ i ] );

    try {
        for( unsigned i = 0; i < args.size(); ++i ) {
            const char *arg = args[ i ];
            if ( arg == string( "--help" ) ) {
                usage();
                return 0;
            } else if ( arg == string( "--forward" ) ) {
                forwardAddress = args[ ++i ];
            } else if ( arg == string( "--source" ) ) {
                uassert( 10266 ,  "can't use --source twice" , source == false );
                uassert( 10267 ,  "source needs more args" , args.size() > i + 2);
                source = true;
                replay = ( args[ ++i ] == string( "FILE" ) );
                if ( replay )
                    file = args[ ++i ];
                else
                    dev = args[ ++i ];
            } else {
                serverPorts.insert( atoi( args[ i ] ) );
            }
        }
    } catch ( ... ) {
        usage();
        return -1;
    }

    if ( !serverPorts.size() )
        serverPorts.insert( 27017 );

    if ( !replay ) {
        if ( !dev ) {
            dev = pcap_lookupdev(errbuf);
            if ( ! dev ) {
                cerr << "error finding device: " << errbuf << endl;
                return -1;
            }
            cout << "found device: " << dev << endl;
        }
        if (pcap_lookupnet(dev, &net, &mask, errbuf) == -1){
            cerr << "can't get netmask: " << errbuf << endl;
            return -1;
        }
        handle = pcap_open_live(dev, SNAP_LEN, 1, 1000, errbuf);
        if ( ! handle ){
            cerr << "error opening device: " << errbuf << endl;
            return -1;
        }
    } else {
        handle = pcap_open_offline(file, errbuf);
        if ( ! handle ){
            cerr << "error opening capture file!" << endl;
            return -1;
        }
    }

    switch ( pcap_datalink( handle ) ){
    case DLT_EN10MB:
        captureHeaderSize = 14;
        break;
    case DLT_NULL:
        captureHeaderSize = 4;
        break;
    default:
        cerr << "don't know how to handle datalink type: " << pcap_datalink( handle ) << endl;
    }

    assert( pcap_compile(handle, &fp, const_cast< char * >( "tcp" ) , 0, net) != -1 );
    assert( pcap_setfilter(handle, &fp) != -1 );

    cout << "sniffing... ";
    for ( set<int>::iterator i = serverPorts.begin(); i != serverPorts.end(); i++ )
        cout << *i << " ";
    cout << endl;

    pcap_loop(handle, 0 , got_packet, NULL);

    pcap_freecode(&fp);
    pcap_close(handle);

    for( map< Connection, DBClientConnection* >::iterator i = forwarder.begin(); i != forwarder.end(); ++i )
        free( i->second );

    return 0;
}