.\" and copyright (c) 2009, Linux Foundation, written by Michael Kerrisk
.\" <mtk.manpages@gmail.com>
.\"
+.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
+.\" %%%LICENSE_END
+.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" for glibc specificities, provide an example.
.\" 2009-01-14 mtk, many edits and changes, rewrote example program.
.\"
-.TH GETIFADDRS 3 2010-10-06 "GNU" "Linux Programmer's Manual"
+.TH GETIFADDRS 3 2014-02-26 "GNU" "Linux Programmer's Manual"
.SH NAME
getifaddrs, freeifaddrs \- get interface addresses
.SH SYNOPSIS
.I sa_family
subfield should be consulted to determine the format of the
address structure.)
+This field may contain a null pointer.
.PP
The
.I ifa_netmask
field points to a structure containing the netmask associated with
.IR ifa_addr ,
if applicable for the address family.
+This field may contain a null pointer.
.PP
Depending on whether the bit
.B IFF_BROADCAST
The
.BR getifaddrs ()
function first appeared in glibc 2.3, but before glibc 2.3.3,
-the implementation only supported IPv4 addresses;
+the implementation supported only IPv4 addresses;
IPv6 support was added in glibc 2.3.3.
-Support of address families other than IPv4 is only available
+Support of address families other than IPv4 is available only
on kernels that support netlink.
.SH CONFORMING TO
Not in POSIX.1-2001.
In this case, the
.I ifa_data
field may contain a pointer to a
+.IR "struct rtnl_link_stats" ,
+defined in
+.IR <linux/if_link.h>
+(in Linux 2.4 and earlier,
.IR "struct net_device_stats" ,
defined in
-.IR <linux/netdevice.h> ,
+.IR <linux/netdevice.h> ),
which contains various interface attributes and statistics.
.SH EXAMPLE
The program below demonstrates the use of
.nf
$ \fB./a.out\fP
-lo address family: 17 (AF_PACKET)
-eth0 address family: 17 (AF_PACKET)
-lo address family: 2 (AF_INET)
- address: <127.0.0.1>
-eth0 address family: 2 (AF_INET)
- address: <10.1.1.4>
-lo address family: 10 (AF_INET6)
- address: <::1>
-eth0 address family: 10 (AF_INET6)
- address: <fe80::2d0:59ff:feda:eb51%eth0>
+lo AF_PACKET (17)
+ tx_packets = 524; rx_packets = 524
+ tx_bytes = 38788; rx_bytes = 38788
+wlp3s0 AF_PACKET (17)
+ tx_packets = 108391; rx_packets = 130245
+ tx_bytes = 30420659; rx_bytes = 94230014
+em1 AF_PACKET (17)
+ tx_packets = 0; rx_packets = 0
+ tx_bytes = 0; rx_bytes = 0
+lo AF_INET (2)
+ address: <127.0.0.1>
+wlp3s0 AF_INET (2)
+ address: <192.168.235.137>
+lo AF_INET6 (10)
+ address: <::1>
+wlp3s0 AF_INET6 (10)
+ address: <fe80::7ee9:d3ff:fef5:1a91%wlp3s0>
.fi
.in
.SS Program source
\&
.nf
+#define _GNU_SOURCE /* To get defns of NI_MAXSERV and NI_MAXHOST */
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
+#include <linux/if_link.h>
-int
-main(int argc, char *argv[])
+int main(int argc, char *argv[])
{
struct ifaddrs *ifaddr, *ifa;
- int family, s;
+ int family, s, n;
char host[NI_MAXHOST];
if (getifaddrs(&ifaddr) == \-1) {
/* Walk through linked list, maintaining head pointer so we
can free list later */
- for (ifa = ifaddr; ifa != NULL; ifa = ifa\->ifa_next) {
+ for (ifa = ifaddr, n = 0; ifa != NULL; ifa = ifa\->ifa_next, n++) {
if (ifa\->ifa_addr == NULL)
continue;
/* Display interface name and family (including symbolic
form of the latter for the common families) */
- printf("%s\t address family: %d%s\\n",
- ifa\->ifa_name, family,
- (family == AF_PACKET) ? " (AF_PACKET)" :
- (family == AF_INET) ? " (AF_INET)" :
- (family == AF_INET6) ? " (AF_INET6)" : "");
+ printf("%\-8s %s (%d)\\n",
+ ifa\->ifa_name,
+ (family == AF_PACKET) ? "AF_PACKET" :
+ (family == AF_INET) ? "AF_INET" :
+ (family == AF_INET6) ? "AF_INET6" : "???",
+ family);
/* For an AF_INET* interface address, display the address */
s = getnameinfo(ifa\->ifa_addr,
(family == AF_INET) ? sizeof(struct sockaddr_in) :
sizeof(struct sockaddr_in6),
- host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
+ host, NI_MAXHOST,
+ NULL, 0, NI_NUMERICHOST);
if (s != 0) {
printf("getnameinfo() failed: %s\\n", gai_strerror(s));
exit(EXIT_FAILURE);
}
- printf("\\taddress: <%s>\\n", host);
+
+ printf("\\t\\taddress: <%s>\\n", host);
+
+ } else if (family == AF_PACKET && ifa\->ifa_data != NULL) {
+ struct rtnl_link_stats *stats = ifa\->ifa_data;
+
+ printf("\\t\\ttx_packets = %10u; rx_packets = %10u\\n"
+ "\\t\\ttx_bytes = %10u; rx_bytes = %10u\\n",
+ stats\->tx_packets, stats\->rx_packets,
+ stats\->tx_bytes, stats\->rx_bytes);
}
}
.BR socket (2),
.BR packet (7),
.BR ifconfig (8)
+.SH COLOPHON
+This page is part of release 3.65 of the Linux
+.I man-pages
+project.
+A description of the project,
+and information about reporting bugs,
+can be found at
+\%http://www.kernel.org/doc/man\-pages/.
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