Проект OpenNet: MAN freeifaddrs (3) Библиотечные вызовы (FreeBSD и Linux)

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freeifaddrs (3)

>> freeifaddrs (3) ( FreeBSD man: Библиотечные вызовы )

BSD mandoc

NAME



getifaddrs

 - get interface addresses

SYNOPSIS

   #include <sys/types.h>
   #include <sys/socket.h>
   #include <ifaddrs.h>
int getifaddrs (struct ifaddrs **ifap);
void freeifaddrs (struct ifaddrs *ifp);

DESCRIPTION

The getifaddrs ();
function stores a reference to a linked list of the network interfaces on the local machine in the memory referenced by Fa ifap . The list consists of ifaddrs structures, as defined in the include file In ifaddrs.h . The ifaddrs structure contains at least the following entries:

    struct ifaddrs   *ifa_next;         /* Pointer to next struct */
    char             *ifa_name;         /* Interface name */
    u_int             ifa_flags;        /* Interface flags */
    struct sockaddr  *ifa_addr;         /* Interface address */
    struct sockaddr  *ifa_netmask;      /* Interface netmask */
    struct sockaddr  *ifa_broadaddr;    /* Interface broadcast address */
    struct sockaddr  *ifa_dstaddr;      /* P2P interface destination */
    void             *ifa_data;         /* Address specific data */

The ifa_next field contains a pointer to the next structure on the list. This field is NULL in last structure on the list.

The ifa_name field contains the interface name.

The ifa_flags field contains the interface flags, as set by ifconfig(8) utility.

The ifa_addr field references either the address of the interface or the link level address of the interface, if one exists, otherwise it is NULL. (The sa_family field of the ifa_addr field should be consulted to determine the format of the ifa_addr address.)

The ifa_netmask field references the netmask associated with ifa_addr if one is set, otherwise it is NULL.

The ifa_broadaddr field, which should only be referenced for non-P2P interfaces, references the broadcast address associated with ifa_addr if one exists, otherwise it is NULL.

The ifa_dstaddr field references the destination address on a P2P interface, if one exists, otherwise it is NULL.

The ifa_data field references address family specific data. For AF_LINK addresses it contains a pointer to the Fa struct if_data (as defined in include file In net/if.h ) which contains various interface attributes and statistics. For all other address families, it contains a pointer to the Fa struct ifa_data (as defined in include file In net/if.h ) which contains per-address interface statistics.

The data returned by getifaddrs ();
is dynamically allocated and should be freed using freeifaddrs ();
when no longer needed.