Date: Sun, 29 Nov 1998 07:07:18 -0800 (PST) From: "Jonathan M. Bresler" <jmb> To: jmb@FreeBSD.ORG (Jonathan M. Bresler) Cc: hackers@FreeBSD.ORG Subject: Re: tun interfaces not returned by SIOCGIFCONF ?? Message-ID: <199811291507.HAA07258@hub.freebsd.org> In-Reply-To: <199811290603.WAA27066@hub.freebsd.org> from "Jonathan M. Bresler" at "Nov 28, 98 10:03:07 pm"
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Jonathan M. Bresler wrote:
> ~~~~~~~~~~~~~~~~~~~~
> in this code snippit, i always call inet_ntoa() eventhough the argument
> may no be an address but rather other data.
>
> code from nmap (printf()'s are my additions):
> for (ifr = (struct ifreq *) pbuf;
> ifr && *((char *) ifr) && ((char *) ifr) < pbuf + ifc.ifc_len;
> ((*(char **) &ifr) += sizeof(ifr->ifr_name) + len)) {
> sin = (struct sockaddr_in *) & ifr->ifr_addr;
> printf("ifc_len: %d (currently at %u)\n", ifc.ifc_len, (char *)ifr - pbuf);
> printf("trying: %s: %s\n", ifr->ifr_name, inet_ntoa(sin->sin_addr));
> if (sin->sin_addr.s_addr == addr->s_addr) {
> /*
> * Stevens does this in UNP, so it may be useful in
> * some cases
> */
> if ((p = strchr(ifr->ifr_name, ':')))
> *p = '\0';
> /*
> * If an app gives me less than 64 bytes, they
> * deserve to be overflowed!
> */
> strncpy(dev, ifr->ifr_name, 63);
> dev[63] = '\0';
> return 1;
> }
> }
the bug in the above code snippit is "len is always the same value".
the for loop increment must be set each time through the loop.
i'll prepare a patch for the port of nmap-1.5.1
jmb
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