Date: Thu, 9 Jul 1998 16:04:11 -0700 (PDT) From: rec@rcousins.com To: FreeBSD-gnats-submit@FreeBSD.ORG Subject: kern/7230: problem with SIOCGIFCONF Message-ID: <199807092304.QAA03280@www.RCousins.com>
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>Number: 7230
>Category: kern
>Synopsis: problem with SIOCGIFCONF
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Jul 9 16:10:01 PDT 1998
>Last-Modified:
>Originator: Robert Cousus
>Organization:
>Release: FreeBSD 2.2.6-RELEASE i386
>Environment:
K6 cpu, 128 megs RAM, 15 gigs Disk, 2 LAN ifces.
>Description:
SIOCGIFCONF does not return an array of struct ifreq with one
entry per network interface.
>How-To-Repeat:
Compile and run the attached program to demonstrate the problem.
(Note: program runs correctly under Solaris 2.5.1.)
-----------------
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <sys/ioctl.h>
char buffer[1<<12];
int main(int argc, char *argv[])
{
int res; /* result from call */
int sock; /* socket file descriptor */
int i; /* loop variable */
struct ifconf ifconf; /* used in test below */
struct ifreq *ptr; /* pointer to walk buffer */
sock = socket(PF_INET, SOCK_DGRAM, 0);
if (sock < 0) {
perror("socket(PF_INET, SOCK_DGRAM, 0)");
exit(1);
}
ifconf.ifc_len = sizeof(buffer); /* establish size of buffer */
ifconf.ifc_buf = buffer; /* point to buffer */
res = ioctl(sock, SIOCGIFCONF, &ifconf);
if (res < 0) {
perror("ioctl(sock, SIOCGIFCONF, &ifconf)");
exit(1);
}
/*
* At this point, the ifconf.ifc_len should tell how many bytes consumed
* in the buffer and ifconf.ifc_req should point to an array of ifreq
* structures.
*
/*
* Test 1: The return value should be a multiple of sizeof(ifreq).
*/
if (ifconf.ifc_len % sizeof(struct ifreq)) {
printf("Failed test1: %d %% %d = %d\n",
ifconf.ifc_len, sizeof(struct ifreq),
ifconf.ifc_len % sizeof(struct ifreq));
}
/*
* Test 2: We should be able to print out the names of all
* interfaces by looping through the array.
*/
ptr = ifconf.ifc_req; /* point to beginning of array */
for (i = 0; i < (ifconf.ifc_len/sizeof(struct ifreq)); i++, ptr++)
printf("Interface %d: %s\n", i, ptr->ifr_name);
exit(0);
}
-----------------
>Fix:
Unknown.
>Audit-Trail:
>Unformatted:
Robert Cousins
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