bin/54151: [PATCH] -i (restrict to one interface) patch from arp(8)

[Yar Tikhiy]

The following reply was made to PR bin/54151; it has been noted by GNATS.

From: Yar Tikhiy <yar at FreeBSD.org>
To: freebsd-gnats-submit at FreeBSD.org, marck at rinet.ru
Cc:  
Subject: Re: bin/54151: [PATCH] -i (restrict to one interface) patch from arp(8)
Date: Thu, 17 Jul 2003 17:35:56 +0400

 The feature you've proposed looks really juicy to me so long as
 there's a router between numerous VLANs under my management, too.
 I've introduced some changes into your patch to improve its style
 and language.  One of my points is using if_nametoindex(3) to check
 if an interface does exist, instead of all that code around sysctl(2).
 Could you please confirm my version of the patch works for you?
 
 -- 
 Yar
 
 Index: arp.8
 ===================================================================
 RCS file: /home/ncvs/src/usr.sbin/arp/arp.8,v
 retrieving revision 1.20
 diff -u -p -r1.20 arp.8
 --- arp.8	27 Dec 2002 10:09:04 -0000	1.20
 +++ arp.8	17 Jul 2003 13:30:20 -0000
 @@ -41,9 +41,11 @@
  .Sh SYNOPSIS
  .Nm
  .Op Fl n
 +.Op Fl i Ar interface
  .Ar hostname
  .Nm
  .Op Fl n
 +.Op Fl i Ar interface
  .Fl a
  .Nm
  .Fl d Ar hostname
 @@ -99,6 +101,12 @@ Alternatively, the
  flag may be combined with the
  .Fl a
  flag to delete all entries.
 +.It Fl i Ar interface
 +Limit the operation scope to the
 +.Tn ARP
 +entries on
 +.Ar interface .
 +Applicable to the display operations only.
  .It Fl n
  Show network addresses as numbers (normally
  .Nm
 Index: arp.c
 ===================================================================
 RCS file: /home/ncvs/src/usr.sbin/arp/arp.c,v
 retrieving revision 1.45
 diff -u -p -r1.45 arp.c
 --- arp.c	3 May 2003 21:06:35 -0000	1.45
 +++ arp.c	17 Jul 2003 13:30:20 -0000
 @@ -104,6 +104,7 @@ static pid_t pid;
  static int nflag;	/* no reverse dns lookups */
  static int aflag;	/* do it for all entries */
  static int s = -1;
 +static char *rifname;
  
  struct	sockaddr_in so_mask;
  struct	sockaddr_inarp blank_sin, sin_m;
 @@ -132,7 +133,7 @@ main(int argc, char *argv[])
  	int rtn = 0;
  
  	pid = getpid();
 -	while ((ch = getopt(argc, argv, "andfsS")) != -1)
 +	while ((ch = getopt(argc, argv, "andfsSi:")) != -1)
  		switch((char)ch) {
  		case 'a':
  			aflag = 1;
 @@ -152,6 +153,9 @@ main(int argc, char *argv[])
  		case 'f' :
  			SETFUNC(F_FILESET);
  			break;
 +		case 'i':
 +			rifname = optarg;
 +			break;
  		case '?':
  		default:
  			usage();
 @@ -171,6 +175,16 @@ main(int argc, char *argv[])
  
  	if (!func)
  		func = F_GET;
 +	if (rifname) {
 +		if (func != F_GET)
 +			errx(1, "-i not applicable to this operation");
 +		if (if_nametoindex(rifname) == 0) {
 +			if (errno == ENXIO)
 +				errx(1, "interface %s does not exist", rifname);
 +			else
 +				err(1, "if_nametoindex(%s)", rifname);
 +		}
 +	}
  	switch (func) {
  	case F_GET:
  		if (aflag) {
 @@ -376,8 +390,11 @@ get(char *host)
  	}
  	search(addr->sin_addr.s_addr, print_entry);
  	if (found_entry == 0) {
 -		printf("%s (%s) -- no entry\n",
 +		printf("%s (%s) -- no entry",
  		    host, inet_ntoa(addr->sin_addr));
 +		if (rifname)
 +			printf(" on %s", rifname);
 +		printf("\n");
  		return(1);
  	}
  	return(0);
 @@ -459,6 +476,7 @@ search(u_long addr, void (*action)(struc
  	struct rt_msghdr *rtm;
  	struct sockaddr_inarp *sin2;
  	struct sockaddr_dl *sdl;
 +	char ifname[IFNAMSIZ];
  
  	mib[0] = CTL_NET;
  	mib[1] = PF_ROUTE;
 @@ -477,6 +495,9 @@ search(u_long addr, void (*action)(struc
  		rtm = (struct rt_msghdr *)next;
  		sin2 = (struct sockaddr_inarp *)(rtm + 1);
  		(char *)sdl = (char *)sin2 + ROUNDUP(sin2->sin_len);
 +		if (rifname && if_indextoname(sdl->sdl_index, ifname) != NULL &&
 +		    strcmp(ifname, rifname))
 +			continue;
  		if (addr) {
  			if (addr != sin2->sin_addr.s_addr)
  				continue;
 @@ -593,8 +614,8 @@ void
  usage(void)
  {
  	fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
 -		"usage: arp [-n] hostname",
 -		"       arp [-n] -a",
 +		"usage: arp [-n] [-i ifname] hostname",
 +		"       arp [-n] [-i ifname] -a",
  		"       arp -d hostname [pub]",
  		"       arp -d -a",
  		"       arp -s hostname ether_addr [temp] [pub]",