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(3PCAP) and pcap_activate(3PCAP) or  with  pcap_open_live(3PCAP).   (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

                     PCAP_IF_WIRELESS
                            set if the device is a wireless interface; this includes IrDA as well
                            as  radio-based networks such as IEEE 802.15.4 and IEEE 802.11, so it
                            doesn't just mean Wi-Fi

                     PCAP_IF_CONNECTION_STATUS
                            a bitmask for an indication of whether the adapter  is  connected  or
                            not;  for  wireless  interfaces, "connected" means "associated with a
                            network"

                     The possible values for the connection status bits are:

                     PCAP_IF_CONNECTION_STATUS_UNKNOWN
                            it's unknown whether the adapter is connected or not

                     PCAP_IF_CONNECTION_STATUS_CONNECTED
                            the adapter is connected

                     PCAP_IF_CONNECTION_STATUS_DISCONNECTED
                            the adapter is disconnected

                     PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE
                            the notion of "connected" and  "disconnected"  don't  apply  to  this
                            interface; for example, it doesn't apply to a loopback device

       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(3PCAP), which frees the list
       pointed to by alldevs.

RETURN VALUE

       pcap_findalldevs() returns 0 on success and PCAP_ERROR on failure; as  indicated,  finding
       no devices is considered success, rather than failure, so 0 will be returned in that case.
       If PCAP_ERROR 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.

BACKWARD COMPATIBILITY

       The  PCAP_IF_UP  and  PCAP_IF_RUNNING constants became available in libpcap release 1.6.1.
       The   PCAP_IF_WIRELESS,   PCAP_IF_CONNECTION_STATUS,    PCAP_IF_CONNECTION_STATUS_UNKNOWN,
       PCAP_IF_CONNECTION_STATUS_CONNECTED,      PCAP_IF_CONNECTION_STATUS_DISCONNECTED,      and
       PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE constants became  available  in  libpcap  release
       1.9.0.

SEE ALSO

       pcap(3PCAP)

                                          23 August 2018                  PCAP_FINDALLDEVS(3PCAP)