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1 /*
2  * Copyright (c) 1999 - 2003
3  * NetGroup, Politecnico di Torino (Italy)
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the Politecnico di Torino nor the names of its
16  * contributors may be used to endorse or promote products derived from
17  * this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  *
31  */
32
33 #ifndef lint
34 static const char rcsid[] _U_ =
35     "@(#) $Header: /tcpdump/master/libpcap/pcap-win32.c,v 1.25.2.3 2005/07/10 17:52:54 risso Exp $ (LBL)";
36 #endif
37
38 #include <pcap-int.h>
39 #include <packet32.h>
40 #include <Ntddndis.h>
41 #ifdef HAVE_DAG_API
42 #include <dagnew.h>
43 #include <dagapi.h>
44 #endif /* HAVE_DAG_API */
45 #ifdef __MINGW32__
46 int* _errno();
47 #define errno (*_errno())
48 #endif /* __MINGW32__ */
49
50 static int pcap_setfilter_win32_npf(pcap_t *, struct bpf_program *);
51 static int pcap_setfilter_win32_dag(pcap_t *, struct bpf_program *);
52 static int pcap_getnonblock_win32(pcap_t *, char *);
53 static int pcap_setnonblock_win32(pcap_t *, int, char *);
54
55 #define PcapBufSize 256000      /*dimension of the buffer in the pcap_t structure*/
56 #define SIZE_BUF 1000000
57
58 /* Equivalent to ntohs(), but a lot faster under Windows */
59 #define SWAPS(_X) ((_X & 0xff) << 8) | (_X >> 8)
60
61 /*
62  * Header that the WinPcap driver associates to the packets.
63  * Once was in bpf.h
64  */
65 struct bpf_hdr {
66         struct timeval  bh_tstamp;      /* time stamp */
67         bpf_u_int32     bh_caplen;      /* length of captured portion */
68         bpf_u_int32     bh_datalen;     /* original length of packet */
69         u_short         bh_hdrlen;      /* length of bpf header (this struct
70                                            plus alignment padding) */
71 };
72
73 /* Start winsock */
74 int 
75 wsockinit()
76 {
77         WORD wVersionRequested;
78         WSADATA wsaData;
79         int err;
80         wVersionRequested = MAKEWORD( 1, 1); 
81         err = WSAStartup( wVersionRequested, &wsaData );
82         if ( err != 0 )
83         {
84                 return -1;
85         }
86         return 0;
87 }
88
89
90 static int
91 pcap_stats_win32(pcap_t *p, struct pcap_stat *ps)
92 {
93
94         if(PacketGetStats(p->adapter, (struct bpf_stat*)ps) != TRUE){
95                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "PacketGetStats error: %s", pcap_win32strerror());
96                 return -1;
97         }
98
99         return 0;
100 }
101
102 static int
103 pcap_read_win32_npf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
104 {
105         int cc;
106         int n = 0;
107         register u_char *bp, *ep;
108
109         cc = p->cc;
110         if (p->cc == 0) {
111                 /*
112                  * Has "pcap_breakloop()" been called?
113                  */
114                 if (p->break_loop) {
115                         /*
116                          * Yes - clear the flag that indicates that it
117                          * has, and return -2 to indicate that we were
118                          * told to break out of the loop.
119                          */
120                         p->break_loop = 0;
121                         return (-2);
122                 }
123
124             /* capture the packets */
125                 if(PacketReceivePacket(p->adapter,p->Packet,TRUE)==FALSE){
126                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read error: PacketReceivePacket failed");
127                         return (-1);
128                 }
129                         
130                 cc = p->Packet->ulBytesReceived;
131
132                 bp = p->Packet->Buffer;
133         } 
134         else
135                 bp = p->bp;
136
137         /*
138          * Loop through each packet.
139          */
140 #define bhp ((struct bpf_hdr *)bp)
141         ep = bp + cc;
142         while (1) {
143                 register int caplen, hdrlen;
144
145                 /*
146                  * Has "pcap_breakloop()" been called?
147                  * If so, return immediately - if we haven't read any
148                  * packets, clear the flag and return -2 to indicate
149                  * that we were told to break out of the loop, otherwise
150                  * leave the flag set, so that the *next* call will break
151                  * out of the loop without having read any packets, and
152                  * return the number of packets we've processed so far.
153                  */
154                 if (p->break_loop) {
155                         if (n == 0) {
156                                 p->break_loop = 0;
157                                 return (-2);
158                         } else {
159                                 p->bp = bp;
160                                 p->cc = ep - bp;
161                                 return (n);
162                         }
163                 }
164                 if (bp >= ep)
165                         break;
166
167                 caplen = bhp->bh_caplen;
168                 hdrlen = bhp->bh_hdrlen;
169
170                 /*
171                  * XXX A bpf_hdr matches a pcap_pkthdr.
172                  */
173                 (*callback)(user, (struct pcap_pkthdr*)bp, bp + hdrlen);
174                 bp += BPF_WORDALIGN(caplen + hdrlen);
175                 if (++n >= cnt && cnt > 0) {
176                         p->bp = bp;
177                         p->cc = ep - bp;
178                         return (n);
179                 }
180         }
181 #undef bhp
182         p->cc = 0;
183         return (n);
184 }
185
186 #ifdef HAVE_DAG_API
187 static int
188 pcap_read_win32_dag(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
189 {
190         u_char *dp = NULL;
191         int     packet_len = 0, caplen = 0;
192         struct pcap_pkthdr      pcap_header;
193         u_char *endofbuf;
194         int n = 0;
195         dag_record_t *header;
196         unsigned erf_record_len;
197         ULONGLONG ts;
198         int cc;
199         unsigned swt;
200         unsigned dfp = p->adapter->DagFastProcess;
201
202         cc = p->cc;
203         if (cc == 0) /* Get new packets only if we have processed all the ones of the previous read */
204         {
205             /* Get new packets from the network */
206                 if(PacketReceivePacket(p->adapter, p->Packet, TRUE)==FALSE){
207                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read error: PacketReceivePacket failed");
208                         return (-1);
209                 }
210
211                 cc = p->Packet->ulBytesReceived;
212                 if(cc == 0)
213                         /* The timeout has expired but we no packets arrived */
214                         return 0;
215                 header = (dag_record_t*)p->adapter->DagBuffer;
216         } 
217         else
218                 header = (dag_record_t*)p->bp;
219         
220         endofbuf = (char*)header + cc;
221         
222         /* 
223          * Cycle through the packets 
224          */
225         do
226         {
227                 erf_record_len = SWAPS(header->rlen);
228                 if((char*)header + erf_record_len > endofbuf)
229                         break;
230
231                 /* Increase the number of captured packets */
232                 p->md.stat.ps_recv++;
233                 
234                 /* Find the beginning of the packet */
235                 dp = ((u_char *)header) + dag_record_size;
236
237                 /* Determine actual packet len */
238                 switch(header->type) 
239                 {
240                 case TYPE_ATM:
241                         packet_len = ATM_SNAPLEN;
242                         caplen = ATM_SNAPLEN;
243                         dp += 4;
244
245                         break;
246
247                 case TYPE_ETH:
248                         swt = SWAPS(header->wlen);
249                         packet_len = swt - (p->md.dag_fcs_bits);
250                         caplen = erf_record_len - dag_record_size - 2;
251                         if (caplen > packet_len)
252                         {
253                                 caplen = packet_len;
254                         }
255                         dp += 2;
256                         
257                         break;
258                 
259                 case TYPE_HDLC_POS:
260                         swt = SWAPS(header->wlen);
261                         packet_len = swt - (p->md.dag_fcs_bits);
262                         caplen = erf_record_len - dag_record_size;
263                         if (caplen > packet_len)
264                         {
265                                 caplen = packet_len;
266                         }
267                         
268                         break;
269                 }
270                 
271                 if(caplen > p->snapshot)
272                         caplen = p->snapshot;
273
274                 /*
275                  * Has "pcap_breakloop()" been called?
276                  * If so, return immediately - if we haven't read any
277                  * packets, clear the flag and return -2 to indicate
278                  * that we were told to break out of the loop, otherwise
279                  * leave the flag set, so that the *next* call will break
280                  * out of the loop without having read any packets, and
281                  * return the number of packets we've processed so far.
282                  */
283                 if (p->break_loop) 
284                 {
285                         if (n == 0) 
286                         {
287                                 p->break_loop = 0;
288                                 return (-2);
289                         } 
290                         else 
291                         {
292                                 p->bp = (char*)header;
293                                 p->cc = endofbuf - (char*)header;
294                                 return (n);
295                         }
296                 }
297
298                 if(!dfp)
299                 {
300                         /* convert between timestamp formats */
301                         ts = header->ts;
302                         pcap_header.ts.tv_sec = (int)(ts >> 32);
303                         ts = (ts & 0xffffffffi64) * 1000000;
304                         ts += 0x80000000; /* rounding */
305                         pcap_header.ts.tv_usec = (int)(ts >> 32);
306                         if (pcap_header.ts.tv_usec >= 1000000) {
307                                 pcap_header.ts.tv_usec -= 1000000;
308                                 pcap_header.ts.tv_sec++;
309                         }
310                 }
311                 
312                 /* No underlaying filtering system. We need to filter on our own */
313                 if (p->fcode.bf_insns) 
314                 {
315                         if (bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen) == 0) 
316                         {
317                                 /* Move to next packet */
318                                 header = (dag_record_t*)((char*)header + erf_record_len);
319                                 continue;
320                         }
321                 }
322                 
323                 /* Fill the header for the user suppplied callback function */
324                 pcap_header.caplen = caplen;
325                 pcap_header.len = packet_len;
326                 
327                 /* Call the callback function */
328                 (*callback)(user, &pcap_header, dp);
329                 
330                 /* Move to next packet */
331                 header = (dag_record_t*)((char*)header + erf_record_len);
332
333                 /* Stop if the number of packets requested by user has been reached*/
334                 if (++n >= cnt && cnt > 0) 
335                 {
336                         p->bp = (char*)header;
337                         p->cc = endofbuf - (char*)header;
338                         return (n);
339                 }
340         }
341         while((u_char*)header < endofbuf);
342         
343   return 1;
344 }
345 #endif /* HAVE_DAG_API */
346
347 /* Send a packet to the network */
348 static int 
349 pcap_inject_win32(pcap_t *p, const void *buf, size_t size){
350         LPPACKET PacketToSend;
351
352         PacketToSend=PacketAllocatePacket();
353         
354         if (PacketToSend == NULL)
355         {
356                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send error: PacketAllocatePacket failed");
357                 return -1;
358         }
359         
360         PacketInitPacket(PacketToSend,(PVOID)buf,size);
361         if(PacketSendPacket(p->adapter,PacketToSend,TRUE) == FALSE){
362                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send error: PacketSendPacket failed");
363                 PacketFreePacket(PacketToSend);
364                 return -1;
365         }
366
367         PacketFreePacket(PacketToSend);
368
369         /*
370          * We assume it all got sent if "PacketSendPacket()" succeeded.
371          * "pcap_inject()" is expected to return the number of bytes
372          * sent.
373          */
374         return size;
375 }
376
377 static void
378 pcap_close_win32(pcap_t *p)
379 {
380         pcap_close_common(p);
381         if (p->adapter != NULL) {
382                 PacketCloseAdapter(p->adapter);
383                 p->adapter = NULL;
384         }
385         if (p->Packet) {
386                 PacketFreePacket(p->Packet);
387                 p->Packet = NULL;
388         }
389 }
390
391 pcap_t *
392 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
393     char *ebuf)
394 {
395         register pcap_t *p;
396         NetType type;
397
398         /* Init WinSock */
399         wsockinit();
400
401         p = (pcap_t *)malloc(sizeof(*p));
402         if (p == NULL) 
403         {
404                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno));
405                 return (NULL);
406         }
407         memset(p, 0, sizeof(*p));
408         p->adapter=NULL;
409
410         p->adapter = PacketOpenAdapter((char*)device);
411         
412         if (p->adapter == NULL)
413         {
414                 free(p);
415                 /* Adapter detected but we are not able to open it. Return failure. */
416                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "Error opening adapter: %s", pcap_win32strerror());
417                 return NULL;
418         }
419         
420         /*get network type*/
421         if(PacketGetNetType (p->adapter,&type) == FALSE)
422         {
423                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "Cannot determine the network type: %s", pcap_win32strerror());
424                 goto bad;
425         }
426         
427         /*Set the linktype*/
428         switch (type.LinkType) 
429         {
430         case NdisMediumWan:
431                 p->linktype = DLT_EN10MB;
432                 break;
433                 
434         case NdisMedium802_3:
435                 p->linktype = DLT_EN10MB;
436                 /*
437                  * This is (presumably) a real Ethernet capture; give it a
438                  * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
439                  * that an application can let you choose it, in case you're
440                  * capturing DOCSIS traffic that a Cisco Cable Modem
441                  * Termination System is putting out onto an Ethernet (it
442                  * doesn't put an Ethernet header onto the wire, it puts raw
443                  * DOCSIS frames out on the wire inside the low-level
444                  * Ethernet framing).
445                  */
446                 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
447                 /*
448                  * If that fails, just leave the list empty.
449                  */
450                 if (p->dlt_list != NULL) {
451                         p->dlt_list[0] = DLT_EN10MB;
452                         p->dlt_list[1] = DLT_DOCSIS;
453                         p->dlt_count = 2;
454                 }
455                 break;
456                 
457         case NdisMediumFddi:
458                 p->linktype = DLT_FDDI;
459                 break;
460                 
461         case NdisMedium802_5:                   
462                 p->linktype = DLT_IEEE802;      
463                 break;
464                 
465         case NdisMediumArcnetRaw:
466                 p->linktype = DLT_ARCNET;
467                 break;
468                 
469         case NdisMediumArcnet878_2:
470                 p->linktype = DLT_ARCNET;
471                 break;
472                 
473         case NdisMediumAtm:
474                 p->linktype = DLT_ATM_RFC1483;
475                 break;
476                 
477         case NdisMediumCHDLC:
478                 p->linktype = DLT_CHDLC;
479                 break;
480
481         case NdisMediumPPPSerial:
482                 p->linktype = DLT_PPP_SERIAL;
483                 break;
484
485         case NdisMediumNull:
486                 p->linktype = DLT_NULL;
487                 break;
488
489         default:
490                 p->linktype = DLT_EN10MB;                       /*an unknown adapter is assumed to be ethernet*/
491                 break;
492         }
493
494         /* Set promisquous mode */
495         if (promisc) PacketSetHwFilter(p->adapter,NDIS_PACKET_TYPE_PROMISCUOUS);
496          else PacketSetHwFilter(p->adapter,NDIS_PACKET_TYPE_ALL_LOCAL);
497
498         /* Set the buffer size */
499         p->bufsize = PcapBufSize;
500
501         /* Store the timeout. Used by pcap_setnonblock() */
502         p->timeout= to_ms;
503
504         /* allocate Packet structure used during the capture */
505         if((p->Packet = PacketAllocatePacket())==NULL)
506         {
507                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "failed to allocate the PACKET structure");
508                 goto bad;
509         }
510
511         if(!(p->adapter->Flags & INFO_FLAG_DAG_CARD))
512         {
513         /* 
514          * Traditional Adapter 
515          */
516                 
517                 p->buffer = (u_char *)malloc(PcapBufSize);
518                 if (p->buffer == NULL) 
519                 {
520                         snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno));
521                         goto bad;
522                 }
523                 
524                 PacketInitPacket(p->Packet,(BYTE*)p->buffer,p->bufsize);
525                 
526                 p->snapshot = snaplen;
527                 
528                 /* allocate the standard buffer in the driver */
529                 if(PacketSetBuff( p->adapter, SIZE_BUF)==FALSE)
530                 {
531                         snprintf(ebuf, PCAP_ERRBUF_SIZE,"driver error: not enough memory to allocate the kernel buffer\n");
532                         goto bad;
533                 }
534                 
535                 /* tell the driver to copy the buffer only if it contains at least 16K */
536                 if(PacketSetMinToCopy(p->adapter,16000)==FALSE)
537                 {
538                         snprintf(ebuf, PCAP_ERRBUF_SIZE,"Error calling PacketSetMinToCopy: %s\n", pcap_win32strerror());
539                         goto bad;
540                 }
541         }
542         else
543 #ifdef HAVE_DAG_API
544         {
545         /* 
546          * Dag Card 
547          */
548                 LONG    status;
549                 HKEY    dagkey;
550                 DWORD   lptype;
551                 DWORD   lpcbdata;
552                 int             postype = 0;
553                 char    keyname[512];
554                 
555                 snprintf(keyname, sizeof(keyname), "%s\\CardParams\\%s", 
556                         "SYSTEM\\CurrentControlSet\\Services\\DAG",
557                         strstr(_strlwr((char*)device), "dag"));
558                 do
559                 {
560                         status = RegOpenKeyEx(HKEY_LOCAL_MACHINE, keyname, 0, KEY_READ, &dagkey);
561                         if(status != ERROR_SUCCESS)
562                                 break;
563                         
564                         status = RegQueryValueEx(dagkey,
565                                 "PosType",
566                                 NULL,
567                                 &lptype,
568                                 (char*)&postype,
569                                 &lpcbdata);
570                         
571                         if(status != ERROR_SUCCESS)
572                         {
573                                 postype = 0;
574                         }
575                         
576                         RegCloseKey(dagkey);
577                 }
578                 while(FALSE);
579                 
580                 
581                 p->snapshot = PacketSetSnapLen(p->adapter, snaplen);
582                 
583                 /* Set the length of the FCS associated to any packet. This value 
584                  * will be subtracted to the packet length */
585                 p->md.dag_fcs_bits = p->adapter->DagFcsLen;
586         }
587 #else
588         goto bad;
589 #endif /* HAVE_DAG_API */
590         
591         PacketSetReadTimeout(p->adapter, to_ms);
592         
593 #ifdef HAVE_DAG_API
594         if(p->adapter->Flags & INFO_FLAG_DAG_CARD)
595         {
596                 /* install dag specific handlers for read and setfilter */
597                 p->read_op = pcap_read_win32_dag;
598                 p->setfilter_op = pcap_setfilter_win32_dag;
599         }
600         else
601         {
602 #endif /* HAVE_DAG_API */
603                 /* install traditional npf handlers for read and setfilter */
604                 p->read_op = pcap_read_win32_npf;
605                 p->setfilter_op = pcap_setfilter_win32_npf;
606 #ifdef HAVE_DAG_API
607         }
608 #endif /* HAVE_DAG_API */
609         p->setdirection_op = NULL;      /* Not implemented. */
610             /* XXX - can this be implemented on some versions of Windows? */
611         p->inject_op = pcap_inject_win32;
612         p->set_datalink_op = NULL;      /* can't change data link type */
613         p->getnonblock_op = pcap_getnonblock_win32;
614         p->setnonblock_op = pcap_setnonblock_win32;
615         p->stats_op = pcap_stats_win32;
616         p->close_op = pcap_close_win32;
617
618         return (p);
619 bad:
620         if (p->adapter)
621             PacketCloseAdapter(p->adapter);
622         if (p->buffer != NULL)
623                 free(p->buffer);
624         if(p->Packet)
625                 PacketFreePacket(p->Packet);
626         /*
627          * Get rid of any link-layer type list we allocated.
628          */
629         if (p->dlt_list != NULL)
630                 free(p->dlt_list);
631         free(p);
632         return (NULL);
633 }
634
635
636 static int
637 pcap_setfilter_win32_npf(pcap_t *p, struct bpf_program *fp)
638 {
639         if(PacketSetBpf(p->adapter,fp)==FALSE){
640                 /*
641                  * Kernel filter not installed.
642                  * XXX - fall back on userland filtering, as is done
643                  * on other platforms?
644                  */
645                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Driver error: cannot set bpf filter: %s", pcap_win32strerror());
646                 return (-1);
647         }
648
649         /*
650          * Discard any previously-received packets, as they might have
651          * passed whatever filter was formerly in effect, but might
652          * not pass this filter (BIOCSETF discards packets buffered
653          * in the kernel, so you can lose packets in any case).
654          */
655         p->cc = 0;
656         return (0);
657 }
658
659 /*
660  * We filter at user level, since the kernel driver does't process the packets
661  */
662 static int 
663 pcap_setfilter_win32_dag(pcap_t *p, struct bpf_program *fp) {
664         
665         if(!fp) 
666         {
667                 strncpy(p->errbuf, "setfilter: No filter specified", sizeof(p->errbuf));
668                 return -1;
669         }
670         
671         /* Install a user level filter */
672         if (install_bpf_program(p, fp) < 0) 
673         {
674                 snprintf(p->errbuf, sizeof(p->errbuf),
675                         "setfilter, unable to install the filter: %s", pcap_strerror(errno));
676                 return -1;
677         }
678         
679         p->md.use_bpf = 0;
680         
681         return (0);
682 }
683
684 static int
685 pcap_getnonblock_win32(pcap_t *p, char *errbuf)
686 {
687         /*
688          * XXX - if there were a PacketGetReadTimeout() call, we
689          * would use it, and return 1 if the timeout is -1
690          * and 0 otherwise.
691          */
692         return (p->nonblock);
693 }
694
695 static int
696 pcap_setnonblock_win32(pcap_t *p, int nonblock, char *errbuf)
697 {
698         int newtimeout;
699
700         if (nonblock) {
701                 /*
702                  * Set the read timeout to -1 for non-blocking mode.
703                  */
704                 newtimeout = -1;
705         } else {
706                 /*
707                  * Restore the timeout set when the device was opened.
708                  * (Note that this may be -1, in which case we're not
709                  * really leaving non-blocking mode.)
710                  */
711                 newtimeout = p->timeout;
712         }
713         if (!PacketSetReadTimeout(p->adapter, newtimeout)) {
714                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
715                     "PacketSetReadTimeout: %s", pcap_win32strerror());
716                 return (-1);
717         }
718         p->nonblock = (newtimeout == -1);
719         return (0);
720 }
721
722 /* Set the driver working mode */
723 int 
724 pcap_setmode(pcap_t *p, int mode){
725         
726         if (p->adapter==NULL)
727         {
728                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "impossible to set mode while reading from a file");
729                 return -1;
730         }
731
732         if(PacketSetMode(p->adapter,mode)==FALSE)
733         {
734                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "driver error: working mode not recognized");
735                 return -1;
736         }
737
738         return 0;
739 }
740
741 /* Set the dimension of the kernel-level capture buffer */
742 int 
743 pcap_setbuff(pcap_t *p, int dim)
744 {
745         if (p->adapter==NULL)
746         {
747                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "The kernel buffer size cannot be set while reading from a file");
748                 return -1;
749         }
750         
751         if(PacketSetBuff(p->adapter,dim)==FALSE)
752         {
753                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "driver error: not enough memory to allocate the kernel buffer");
754                 return -1;
755         }
756         return 0;
757 }
758
759 /*set the minimum amount of data that will release a read call*/
760 int 
761 pcap_setmintocopy(pcap_t *p, int size)
762 {
763         if (p->adapter==NULL)
764         {
765                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Impossible to set the mintocopy parameter on an offline capture");
766                 return -1;
767         }       
768
769         if(PacketSetMinToCopy(p->adapter, size)==FALSE)
770         {
771                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "driver error: unable to set the requested mintocopy size");
772                 return -1;
773         }
774         return 0;
775 }