NAME

       pcap_findalldevs, pcap_freealldevs - get a list of capture devices, and free that list

SYNOPSIS

       #include <pcap/pcap.h>

       char errbuf[PCAP_ERRBUF_SIZE];

       int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf);
       void pcap_freealldevs(pcap_if_t *alldevs);

DESCRIPTION

       pcap_findalldevs()  constructs  a  list  of  network  devices  that  can be opened with pcap_create() and
       pcap_activate() or with pcap_open_live().  (Note that there may be network devices that cannot be  opened
       by  the  process  calling pcap_findalldevs(), because, for example, that process does not have sufficient
       privileges to open them for  capturing;  if  so,  those  devices  will  not  appear  on  the  list.)   If
       pcap_findalldevs()  succeeds,  the pointer pointed to by alldevsp is set to point to the first element of
       the list, or to NULL if no devices were found (this is considered success).  Each element of the list  is
       of type pcap_if_t, and has the following members:

              next   if  not  NULL,  a pointer to the next element in the list; NULL for the last element of the
                     list

              name   a pointer to a string giving a name for the device to pass to pcap_open_live()

              description
                     if not NULL, a pointer to a string giving a human-readable description of the device

              addresses
                     a pointer to the first element of a list of network addresses for the device,  or  NULL  if
                     the device has no addresses

              flags  device flags:

                     PCAP_IF_LOOPBACK
                            set if the device is a loopback interface

                     PCAP_IF_UP
                            set if the device is up

                     PCAP_IF_RUNNING
                            set if the device is running

       Each element of the list of addresses is of type pcap_addr_t, and has the following members:

              next   if  not  NULL,  a pointer to the next element in the list; NULL for the last element of the
                     list

              addr   a pointer to a struct sockaddr containing an address

              netmask
                     if not NULL, a pointer to a struct sockaddr that contains the netmask corresponding to  the
                     address pointed to by addr

              broadaddr
                     if  not  NULL,  a  pointer  to  a  struct  sockaddr  that  contains  the  broadcast address
                     corresponding to the address pointed to by addr; may be null if the device doesn't  support
                     broadcasts

              dstaddr
                     if  not  NULL,  a  pointer  to  a  struct  sockaddr  that  contains the destination address
                     corresponding to the address pointed to by addr; may be null if the device isn't  a  point-
                     to-point interface

       Note  that  the addresses in the list of addresses might be IPv4 addresses, IPv6 addresses, or some other
       type of addresses, so you must check the sa_family member of the struct sockaddr before interpreting  the
       contents  of  the  address;  do not assume that the addresses are all IPv4 addresses, or even all IPv4 or
       IPv6 addresses.  IPv4 addresses have the value AF_INET, IPv6 addresses have  the  value  AF_INET6  (which
       older operating systems that don't support IPv6 might not define), and other addresses have other values.
       Whether  other  addresses  are  returned, and what types they might have is platform-dependent.  For IPv4
       addresses, the struct sockaddr pointer can be interpreted as if it pointed to a struct  sockaddr_in;  for
       IPv6 addresses, it can be interpreted as if it pointed to a struct sockaddr_in6.

       The list of devices must be freed with pcap_freealldevs(), which frees the list pointed to by alldevs.

RETURN VALUE

       pcap_findalldevs() returns 0 on success and -1 on failure; as indicated, finding no devices is considered
       success, rather than failure, so 0 will be returned in that case.  If -1 is returned, errbuf is filled in
       with an appropriate error message.  errbuf is assumed to be able to hold at least PCAP_ERRBUF_SIZE chars.

SEE ALSO

       pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP), pcap_open_live(3PCAP)

                                                 10 January 2014                         PCAP_FINDALLDEVS(3PCAP)