Winpcap MinGW compile error

Question

I'm experimenting with WinPcap 4.1.1 libraries for Windows, but I can't manage to compile even example source provided with the library.

I'm getting these errors:

'PCAP_OPENFLAG_PROMISCUOUS' undeclared (first use in this function)
'PCAP_SRC_IF_STRING' undeclared (first use in this function)

And bunch of warnings:

implicit declaration of function 'localtime_s'
implicit declaration of function 'pcap_findalldevs_ex'
implicit declaration of function 'pcap_open'
implicit declaration of function 'scanf_s'

I Googled up a bit and found that I should add a line #define HAVE_REMOTE (I have no clue what does it do) but it leads in much more errors like this:

undefined reference to 'pcap_open'
undefined reference to 'pcap_findalldevs_ex'
undefined reference to 'localtime_s'

The "pcap.h" seems to be included properly (eclipse does not report any including errors). I have copied the *.lib files into MinGW/lib direcotry and set this path in the Path and Symbols->Library Paths (eclipse project properties)

I have no idea what to try next. Any ideas are welcome. Thanks in advance

Here's the code:

#include "pcap.h"

/* prototype of the packet handler */
void packet_handler(u_char *param, const struct pcap_pkthdr *header,
const u_char *pkt_data);

int main()
{
pcap_if_t *alldevs;
pcap_if_t *d;
int inum;
int i=0;
pcap_t *adhandle;
char errbuf[PCAP_ERRBUF_SIZE];

       /* Retrieve the device list on the local machine */
       if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL, &alldevs, errbuf) == -1)
       {
               fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
               exit(1);
       }

       /* Print the list */
       for(d=alldevs; d; d=d->next)
       {
               printf("%d. %s", ++i, d->name);
               if (d->description)
                       printf(" (%s)\n", d->description);
               else
                       printf(" (No description available)\n");
       }

       if(i==0)
       {
               printf("\nNo interfaces found! Make sure WinPcap is installed.\n");
               return -1;
       }

       printf("Enter the interface number (1-%d):",i);
       scanf_s("%d", &inum);

       if(inum < 1 || inum > i)
       {
               printf("\nInterface number out of range.\n");
               /* Free the device list */
               pcap_freealldevs(alldevs);
               return -1;
       }

       /* Jump to the selected adapter */
       for(d=alldevs, i=0; i< inum-1 ;d=d->next, i++);

       /* Open the device */
       if ( (adhandle= pcap_open(d->name,                      // name of the device
                                                         65536,                        // portion of the packet to capture
                                                                                               // 65536 guarantees that the whole packet will be captured
on all the link layers
                                                         PCAP_OPENFLAG_PROMISCUOUS,    // promiscuous mode
                                                         1000,                         // read timeout
                                                         NULL,                         // authentication on the remote machine
                                                         errbuf                        // error buffer
                                                         ) ) == NULL)
       {
               fprintf(stderr,"\nUnable to open the adapter. %s is not supported by
WinPcap\n", d->name);
               /* Free the device list */
               pcap_freealldevs(alldevs);
               return -1;
       }

       printf("\nlistening on %s...\n", d->description);

       /* At this point, we don't need any more the device list. Free it */
       pcap_freealldevs(alldevs);

       /* start the capture */
       pcap_loop(adhandle, 0, packet_handler, NULL);

       return 0;
}


/* Callback function invoked by libpcap for every incoming packet */
void packet_handler(u_char *param, const struct pcap_pkthdr *header,
const u_char *pkt_data)
{
       struct tm ltime;
       char timestr[16];
       time_t local_tv_sec;

       /*
        * unused variables
        */
       (VOID)(param);
       (VOID)(pkt_data);

       /* convert the timestamp to readable format */
       local_tv_sec = header->ts.tv_sec;
       localtime_s(&ltime, &local_tv_sec);
       strftime( timestr, sizeof timestr, "%H:%M:%S", &ltime);

       printf("%s,%.6d len:%d\n", timestr, header->ts.tv_usec, header->len);

}

Answer 1

This is somewhat loosely related, but I found it problematic to overcome, so I want to contribute, so other people looking into this thread actually find the solution.

The order of parameters you are passing to GCC is important, you need to specify your ".c" file before the "-lwpcap", otherwise you will get the linking errors: like

iflist.c:(.text+0x9d): undefined reference to `pcap_freealldevs'

or

sendpack.c:(.text+0x178): undefined reference to `pcap_close'

It's nothing wrong with your mingw installation, Windows 7 or XP, 64-bit or 32-bit, it's just the order of the arguments passed to GCC.

So the actual command I used for compiling was:

cd C:\install\winpcap\WpdPack_4_1_2\WpdPack\Examples-pcap\iflist
gcc -I ../../include -L ../../lib iflist.c -lwpcap -o iflist.exe

I hope this helps.

Answer 2

You can replace your localtime_s call with:

localtime_r(&local_tv_sec, &ltime);

(Note the swapped arguments.)

Also, replace your scanf_s call with scanf .

localtime_s() and scanf_s() are Microsoft-specific extensions, and are not available in MinGW.