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PCAP_FINDALLDEVS(3)                                  PCAP_FINDALLDEVS(3)




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);
       pcap_freealldevs(3) *alldevs);


DESCRIPTION

       pcap_findalldevs() constructs a list of network devices that can be
       opened with pcap_create(3) and pcap_activate(3) or with
       pcap_open_live(3).  (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(3), 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(3)



                                 23 August 2018          PCAP_FINDALLDEVS(3)

libpcap 1.10.2 - Generated Mon Jan 2 08:01:15 CST 2023
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