From owner-freebsd-net@FreeBSD.ORG  Mon Feb 23 22:49:06 2004
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id B030816A4CE
	for <freebsd-net@freebsd.org>; Mon, 23 Feb 2004 22:49:06 -0800 (PST)
Received: from out002.verizon.net (out002pub.verizon.net [206.46.170.141])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 5D23543D2F
	for <freebsd-net@freebsd.org>; Mon, 23 Feb 2004 22:49:06 -0800 (PST)
	(envelope-from cswiger@mac.com)
Received: from mac.com ([68.160.202.196]) by out002.verizon.net
          (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP
          id <20040224064905.LRVE23576.out002.verizon.net@mac.com>;
          Tue, 24 Feb 2004 00:49:05 -0600
Message-ID: <403AF3D9.5070506@mac.com>
Date: Tue, 24 Feb 2004 01:48:57 -0500
From: Chuck Swiger <cswiger@mac.com>
Organization: The Courts of Chaos
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US;
	rv:1.6) Gecko/20040113
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: "Ronald F. Guilmette" <rfg@monkeys.com>
References: <46800.1077593230@monkeys.com>
In-Reply-To: <46800.1077593230@monkeys.com>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
X-Authentication-Info: Submitted using SMTP AUTH at out002.verizon.net from
	[68.160.202.196] at Tue, 24 Feb 2004 00:49:05 -0600
cc: freebsd-net@freebsd.org
Subject: Re: Finding all IPv4 addresses associated with INADDR_ANY (?)
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 24 Feb 2004 06:49:06 -0000

Ronald F. Guilmette wrote:
> Given a socket which has been properly created, opened, and then bound
> to some port and the special INADDR_ANY ``wildcard'' address, I need
> to be able to them programatically find all of the IPv4 addresses that
> the socket was just bound to.

Try something like the following:

     struct ifaddrs *if_ptr, *ifap;

     if (getifaddrs(&ifap) == -1) {
         fatal(strerror(errno));
             /*NOTREACHED*/
     }

         /* iterate over the list of interfaces on the machine */
     for (if_ptr = ifap; if_ptr; if_ptr = if_ptr->ifa_next) {
         switch (if_ptr->ifa_addr->sa_family) {
           case AF_INET:
                 /* check that the interface is UP before we try to use it */
             flags = if_ptr->ifa_flags;
             if (!(flags & IFF_UP)) break;
	        /* do something here using if_ptr->ifa_addr */

           case AF_INET6:
                 /* do something else for IPv6... */
         }
     }

...although be sure to call ntohl() on the address to get things in the local 
byte-ordering...

-- 
-Chuck