kern/165863

[Eric van Gyzen]

The following reply was made to PR kern/165863; it has been noted by GNATS.

From: Eric van Gyzen <eric at vangyzen.net>
To: Gleb Smirnoff <glebius at FreeBSD.org>
Cc: Eric van Gyzen <eric_van_gyzen at dell.com>, <emaste at FreeBSD.org>,
	<bug-followup at FreeBSD.org>, <rysto32 at gmail.com>
Subject: Re: kern/165863
Date: Fri, 9 Mar 2012 09:26:51 -0600

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 On 03/09/12 03:20, Gleb Smirnoff wrote:
 >    Hello, Eric and Ed.
 >
 >    Can you look at this patch? I decided to utilize newer callout API,
 > that allows to delegate lock retrieval to the callout subsystem, and
 > this makes things simplier. Hope that should work.
 >
 >    Patch is against head.
 
 Doesn't arptimer() still need to acquire the if_afdata_lock in order to 
 free the entry in the normal case (when the llentry is still in the hash 
 bucket list)?
 
 With this patch, in_lltable_prefix_free() no longer guarantees that all 
 the relevant llentries will be freed when it returns.  I don't see any 
 immediate breakage, but it's a notable change in behavior.
 
 >    Eric, can you please send me your test programs, that you use to
 > reproduce the bug?
 
 Attached is a C program to add and remove the interface address.  To 
 drive traffic, I just used "ping -f".
 
 Thanks for your help.
 
 Eric
 
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 /*-
  * Copyright (c) 2012 Dell, Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 
 #include <net/if.h>
 
 #include <netinet/in.h>
 
 #include <arpa/inet.h>
 
 #include <err.h>
 #include <errno.h>
 #include <signal.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
 
 int sockfd = -1;
 struct ifreq ifr;
 struct sockaddr_in * const sin4 = (struct sockaddr_in *) &ifr.ifr_addr;
 const char *ifname;
 struct in_addr addr, mask, brdaddr;
 
 unsigned int iterations = 0;
 bool sigint_received = false;
 
 static void
 report(void)
 {
     printf("%u iterations\n", iterations);
 }
 
 static void __dead2
 usage()
 {
     errx(1, "usage: ifconf <ifname> <addr> <mask> <brdaddr> [1]");
 }
 
 static void
 ifconf(void)
 {
     bzero(&ifr, sizeof ifr);
     strlcpy(ifr.ifr_name, ifname, sizeof ifr.ifr_name);
 
     sin4->sin_family = AF_INET;
     sin4->sin_len = sizeof (*sin4);
     sin4->sin_addr = addr;
     if (ioctl(sockfd, SIOCDIFADDR, &ifr)) {
         if (iterations == 0 && errno == EADDRNOTAVAIL) {
             // OK, it wasn't there when we started.
         } else {
             err(1,  "SIOCDIFADDR");
         }
     }
 
     if (ioctl(sockfd, SIOCSIFADDR, &ifr)) {
         err(1,  "SIOCSIFADDR");
     }
 
 #if 0
     sin4->sin_addr = mask;
     if (ioctl(sockfd, SIOCSIFNETMASK, &ifr)) {
         err(1,  "SIOCSIFNETMASK");
     }
 
     sin4->sin_addr = brdaddr;
     if (ioctl(sockfd, SIOCSIFBRDADDR, &ifr)) {
         err(1,  "SIOCSIFBRDADDR");
     }
 #endif
 }
 
 static void
 sigint_handler(int signo __unused)
 {
     sigint_received = true;
 }
 
 int
 main(int argc, const char *argv[])
 {
     if (argc != 5 && argc != 6) {
         usage();
     }
 
     ifname = argv[1];
     if (inet_pton(AF_INET, argv[2], &addr) != 1) {
         err(1, "inet_pton(%s)", argv[2]);
     }
     if (inet_pton(AF_INET, argv[3], &mask) != 1) {
         err(1, "inet_pton(%s)", argv[3]);
     }
     if (inet_pton(AF_INET, argv[4], &brdaddr) != 1) {
         err(1, "inet_pton(%s)", argv[4]);
     }
 
     sockfd = socket(AF_INET, SOCK_DGRAM, 0);
     if (sockfd < 0) {
         err(1, "socket");
     }
 
     if (argc == 6 && atoi(argv[5]) == 1) {
         ifconf();
         return (0);
     }
 
     atexit(report);
     signal(SIGINT, sigint_handler);
 
     while (!sigint_received) {
         ifconf();
         iterations++;
     }
     putchar('\n');
 
     return (0);
 }
 
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