[Winpcap-users] Network crash when sending a certain amount ofpackets with pcap_sendpacket

[Gianluca Varenni]

RJ,

what kind of adapter are you using?

Have a nice day
GV


----- Original Message ----- 
From: "RJ" <RJdaMasterOfDesaster at t-online.de>
To: <winpcap-users at winpcap.org>
Sent: Wednesday, May 17, 2006 6:28 AM
Subject: [Winpcap-users] Network crash when sending a certain amount 
ofpackets with pcap_sendpacket


> Hello erverybody,
>
> today I got myself back to examine a strange problem in WinPcap. It 
> started
> a year or so ago when I wrote some programs which sent some network 
> traffic
> with WinPcap / Packet.dll. It worked fine with WinPCap 3.0 and 3.1 under
> Win2k SP4 on an old AMD Duron machine with an realtek adapter.
> In between, I got myself a centrino notebook with WinXP Pro SP1, and it
> didn't work. The use of my programs on the laptop even caused a crash of 
> the
> network system of WinXP, that is windows could not send or receive any
> packets any more and had to be rebooted to fix.
>
> I could not see the problem with my laptop and programs and thought it
> refused to work because I used the Packet.dll interface and not pcap. But
> then my desktop machine went to computer heaven because of an processor
> fault, and I had to focus on the laptop.
> Since in that time I was not motivated to rewrite my programs to test, I
> left it aside.
> But now I am motivated, and started to test for the possible errors. I 
> found
> some very strange things:
> I used the sendpack example from the wpdpack and modified it to be able to
> send a couple of packets to the net. I compiled it with Visual Studio, and
> for test purposes with lcc too. The thing I got is the following:
> When starting the laptop and sending less than 15 packets over the 
> ethernet
> adapter, all kept alright. The packets could also be seen with windump, 
> all
> sent correctly.
> But if I try to send more packets, so that the total amount of packets 
> sent
> by sendpack since starting the system reaches 15, the network system 
> crashes
> in the above described manner. Deactivation of the npf driver after that
> changed nothing.
> This was with WinPcap 4.0 alpha, with 3.1 and 3.2 beta it were less 
> packets
> (6 - 10), but the same effect. The problem also  persists on WinXP SP2.
> Because of this, I think there is some fault in the npf driver or windows
> xp, since it worked under Win2K.
> Any suggestions?
>
> Thanks for your efforts
> Roger John
>
> PS: Following is the code of the modified sendpack program. Some code is
> from WpdPack, some from me, just to mention it.
>
> -------------------code sendpack.c start-------------------
>
> #include <stdlib.h>
> #include <stdio.h>
>
> #include <pcap.h>
>
> int npacks = 1,if_num = 1,timeout = 1000;
>
> int list_devs(void) {
> pcap_if_t *alldevs;
> pcap_if_t *d;
> char errbuf[PCAP_ERRBUF_SIZE+1];
> int n = 0;
> printf("This is a test file for libpcap, version
> %s\r\n",pcap_lib_version);
> printf("Listing devices...\r\n");
> /* Retrieve the device list */
> if(pcap_findalldevs(&alldevs, errbuf) == -1)
> {
> fprintf(stderr,"Error while listing devices:
> pcap_findalldevs: %s\r\n", errbuf);
> return(-1);
> }
> /* Scan the list printing every entry */
> for(d=alldevs;d;d=d->next)
> {
> n++;
> printf("%d. ",n);
> if(d->name) {
> printf("%s: ",d->name);
> if(d->description)
> printf("%s\r\n",d->description);
> else
> printf("<no description available>\r\n");
> } else
> printf("<no name available>\r\n");
> }
> /* Free the device list */
> pcap_freealldevs(alldevs);
> return(n);
> }
> pcap_t *open_dev_by_number(unsigned int num,int snap_len,int promisc,int
> to_ms) {
> pcap_t *fp;
> pcap_if_t *alldevs;
> pcap_if_t *d;
> char errbuf[PCAP_ERRBUF_SIZE+1];
> int n = num;
> fp = NULL;
> if(!num)
> return(fp);
> /* Retrieve the device list */
> if(pcap_findalldevs(&alldevs, errbuf) == -1)
> {
> fprintf(stderr,"Error while opening device:
> pcap_findalldevs: %s\r\n", errbuf);
> return(fp);
> }
> /* Scan the list for the entry */
> d=alldevs;
> while(d&&(--n)) d = d->next;
> if(d) {
> /* Open the adapter */
> if (!(fp =
> pcap_open_live(d->name,snap_len,promisc,to_ms,errbuf)))
> fprintf(stderr,"Error while opening device %u:
> \r\n",num,errbuf);
> } else {
> fprintf(stderr,"Error while opening device %u: device not
> found\r\n",num);
> }
> /* Free the device list */
> pcap_freealldevs(alldevs);
> return(fp);
> }
> void Usage(void)
> {
> fprintf(stderr,"sendpack: testing the sending capabilities of
> WinPcap\r\n");
> fprintf(stderr,"usage: send_pack [-l] [-n<n_packs>] [-i<if_num>]
> [-t<timeout>] \r\n");
> fprintf(stderr,"       -n : number of packets to send\r\n");
> fprintf(stderr,"       -i : select interface to use (default is
> first found)\r\n");
> fprintf(stderr,"       -l : list available interfaces and
> exit\r\n");
> fprintf(stderr,"       -t : specify the timeout value in
> milliseconds, default is 1000\r\n");
> }
> int handle_options(int argc,char **argv)
> {
> int i,firstnonoption=0;
>
> for (i=1; i< argc;i++) {
> if (argv[i][0] == '-') {
> switch (argv[i][1]) {
> case '?': Usage();
> exit(0);
> case 'i': if_num = atoi(argv[i]+2);
> break;
> case 'l': list_devs();
> exit(0);
> case 'n': npacks = atoi(argv[i]+2);
> break;
> case 't': timeout = atoi(argv[i]+2);
> break;
> case 'h':
> case 'H': if
> (!stricmp(argv[i]+1,"help")) {
> Usage();
> exit(0);
> }
> default:
> fprintf(stderr,"unknown option
> \"%s\"\n",argv[i]);
> break;
> }
> }
> else {
> firstnonoption = i;
> break;
> }
> }
> return(firstnonoption);
> }
> int main(int argc, char **argv)
> {
> pcap_t *adap;
> u_char packet[100];
> int i;
> i = handle_options(argc,argv);
> /* If no arguments we call the Usage routine and exit */
> /* if (argc <= 1)
> {
> Usage();
> return(1);
> }
> */
> /* Open adapter */
> if(!(adap = open_dev_by_number(if_num,65536,1,timeout))) {
> printf("Now exiting...\r\n");
> return(2);
> }
> /* Supposing to be on ethernet, set mac destination to 1:1:1:1:1:1
> */
> packet[0]=1;
> packet[1]=1;
> packet[2]=1;
> packet[3]=1;
> packet[4]=1;
> packet[5]=1;
>
> /* set mac source to 2:2:2:2:2:2 */
> packet[6]=2;
> packet[7]=2;
> packet[8]=2;
> packet[9]=2;
> packet[10]=2;
> packet[11]=2;
>
> /* Fill the rest of the packet */
> for(i=12;i<100;i++)
> {
> packet[i]=i%256;
> }
>
> /* Send down the packet */
> for(i=1;i<=npacks;i++)
> if (pcap_sendpacket(adap, // Adapter
> packet, // buffer with the
> packet
> 100 // size
> ) != 0)
> {
> fprintf(stderr,"\nError sending packet %d:
> \n",i,pcap_geterr(adap));
> return(3);
> }
>
> pcap_close(adap);
> return(0);
> }
> -------------------code sendpack.c end-------------------
>
>
>
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