1
0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-25 11:37:56 +00:00
freebsd/usr.sbin/arp/arp.c
Jordan K. Hubbard 95319e1733 Make arp command actually behave as documented with the addition of a -f
flag.  The getopt handling in here is actually pretty bogus (not Phil's
fault - it's original sin) but the general approach is working so I'm not
going to break it.  Some small tweaks of my own to add error checking to what
was originally submitted.  Strange how nobody noticed that the flag was
documented but completely missing from the code before! [jkh].
Submitted by:	Phil Taylor <phil@zipmail.co.uk>
1995-08-03 03:56:48 +00:00

520 lines
12 KiB
C

/*
* Copyright (c) 1984, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Sun Microsystems, Inc.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1984, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)arp.c 8.2 (Berkeley) 1/2/94";
#endif /* not lint */
/*
* arp - display, set, and delete arp table entries
*/
#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <nlist.h>
#include <stdio.h>
#include <paths.h>
extern int errno;
static int pid;
static int kflag;
static int nflag;
static int s = -1;
main(argc, argv)
int argc;
char **argv;
{
int ch;
pid = getpid();
while ((ch = getopt(argc, argv, "andfs")) != EOF)
switch((char)ch) {
case 'a':
dump(0);
exit(0);
case 'd':
if (argc < 3 || argc > 4)
usage();
delete(argv[2], argv[3]);
exit(0);
case 'n':
nflag = 1;
continue;
case 's':
if (argc < 4 || argc > 7)
usage();
exit(set(argc-2, &argv[2]) ? 1 : 0);
case 'f' :
if (argc != 3)
usage();
file(argv[2]);
exit(0);
case '?':
default:
usage();
}
if (argc != 2)
usage();
get(argv[1]);
exit(0);
}
/*
* Process a file to set standard arp entries
*/
file(name)
char *name;
{
FILE *fp;
int i, retval;
char line[100], arg[5][50], *args[5];
if ((fp = fopen(name, "r")) == NULL) {
fprintf(stderr, "arp: cannot open %s\n", name);
exit(1);
}
args[0] = &arg[0][0];
args[1] = &arg[1][0];
args[2] = &arg[2][0];
args[3] = &arg[3][0];
args[4] = &arg[4][0];
retval = 0;
while(fgets(line, 100, fp) != NULL) {
i = sscanf(line, "%s %s %s %s %s", arg[0], arg[1], arg[2],
arg[3], arg[4]);
if (i < 2) {
fprintf(stderr, "arp: bad line: %s\n", line);
retval = 1;
continue;
}
if (set(i, args))
retval = 1;
}
fclose(fp);
return (retval);
}
getsocket() {
if (s < 0) {
s = socket(PF_ROUTE, SOCK_RAW, 0);
if (s < 0) {
perror("arp: socket");
exit(1);
}
}
}
struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
int expire_time, flags, export_only, doing_proxy, found_entry;
struct {
struct rt_msghdr m_rtm;
char m_space[512];
} m_rtmsg;
/*
* Set an individual arp entry
*/
set(argc, argv)
int argc;
char **argv;
{
struct hostent *hp;
register struct sockaddr_inarp *sin = &sin_m;
register struct sockaddr_dl *sdl;
register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
u_char *ea;
char *host = argv[0], *eaddr = argv[1];
getsocket();
argc -= 2;
argv += 2;
sdl_m = blank_sdl;
sin_m = blank_sin;
sin->sin_addr.s_addr = inet_addr(host);
if (sin->sin_addr.s_addr == -1) {
if (!(hp = gethostbyname(host))) {
fprintf(stderr, "arp: %s: ", host);
herror((char *)NULL);
return (1);
}
bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
sizeof sin->sin_addr);
}
ea = (u_char *)LLADDR(&sdl_m);
if (ether_aton(eaddr, ea) == 0)
sdl_m.sdl_alen = 6;
doing_proxy = flags = export_only = expire_time = 0;
while (argc-- > 0) {
if (strncmp(argv[0], "temp", 4) == 0) {
struct timeval time;
gettimeofday(&time, 0);
expire_time = time.tv_sec + 20 * 60;
}
else if (strncmp(argv[0], "pub", 3) == 0) {
flags |= RTF_ANNOUNCE;
doing_proxy = SIN_PROXY;
} else if (strncmp(argv[0], "trail", 5) == 0) {
printf("%s: Sending trailers is no longer supported\n",
host);
}
argv++;
}
tryagain:
if (rtmsg(RTM_GET) < 0) {
perror(host);
return (1);
}
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
if (sdl->sdl_family == AF_LINK &&
(rtm->rtm_flags & RTF_LLINFO) &&
!(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
case IFT_ISO88024: case IFT_ISO88025:
goto overwrite;
}
if (doing_proxy == 0) {
printf("set: can only proxy for %s\n", host);
return (1);
}
if (sin_m.sin_other & SIN_PROXY) {
printf("set: proxy entry exists for non 802 device\n");
return(1);
}
sin_m.sin_other = SIN_PROXY;
export_only = 1;
goto tryagain;
}
overwrite:
if (sdl->sdl_family != AF_LINK) {
printf("cannot intuit interface index and type for %s\n", host);
return (1);
}
sdl_m.sdl_type = sdl->sdl_type;
sdl_m.sdl_index = sdl->sdl_index;
return (rtmsg(RTM_ADD));
}
/*
* Display an individual arp entry
*/
get(host)
char *host;
{
struct hostent *hp;
struct sockaddr_inarp *sin = &sin_m;
u_char *ea;
sin_m = blank_sin;
sin->sin_addr.s_addr = inet_addr(host);
if (sin->sin_addr.s_addr == -1) {
if (!(hp = gethostbyname(host))) {
fprintf(stderr, "arp: %s: ", host);
herror((char *)NULL);
exit(1);
}
bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
sizeof sin->sin_addr);
}
dump(sin->sin_addr.s_addr);
if (found_entry == 0) {
printf("%s (%s) -- no entry\n",
host, inet_ntoa(sin->sin_addr));
exit(1);
}
}
/*
* Delete an arp entry
*/
delete(host, info)
char *host;
char *info;
{
struct hostent *hp;
register struct sockaddr_inarp *sin = &sin_m;
register struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
struct sockaddr_dl *sdl;
u_char *ea;
char *eaddr;
if (info && strncmp(info, "pro", 3) )
export_only = 1;
getsocket();
sin_m = blank_sin;
sin->sin_addr.s_addr = inet_addr(host);
if (sin->sin_addr.s_addr == -1) {
if (!(hp = gethostbyname(host))) {
fprintf(stderr, "arp: %s: ", host);
herror((char *)NULL);
return (1);
}
bcopy((char *)hp->h_addr, (char *)&sin->sin_addr,
sizeof sin->sin_addr);
}
tryagain:
if (rtmsg(RTM_GET) < 0) {
perror(host);
return (1);
}
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
if (sdl->sdl_family == AF_LINK &&
(rtm->rtm_flags & RTF_LLINFO) &&
!(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
case IFT_ISO88024: case IFT_ISO88025:
goto delete;
}
}
if (sin_m.sin_other & SIN_PROXY) {
fprintf(stderr, "delete: can't locate %s\n",host);
return (1);
} else {
sin_m.sin_other = SIN_PROXY;
goto tryagain;
}
delete:
if (sdl->sdl_family != AF_LINK) {
printf("cannot locate %s\n", host);
return (1);
}
if (rtmsg(RTM_DELETE) == 0)
printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr));
}
/*
* Dump the entire arp table
*/
dump(addr)
u_long addr;
{
int mib[6];
size_t needed;
char *host, *malloc(), *lim, *buf, *next;
struct rt_msghdr *rtm;
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
extern int h_errno;
struct hostent *hp;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = AF_INET;
mib[4] = NET_RT_FLAGS;
mib[5] = RTF_LLINFO;
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
quit("route-sysctl-estimate");
if ((buf = malloc(needed)) == NULL)
quit("malloc");
if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
quit("actual retrieval of routing table");
lim = buf + needed;
for (next = buf; next < lim; next += rtm->rtm_msglen) {
rtm = (struct rt_msghdr *)next;
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin + 1);
if (addr) {
if (addr != sin->sin_addr.s_addr)
continue;
found_entry = 1;
}
if (nflag == 0)
hp = gethostbyaddr((caddr_t)&(sin->sin_addr),
sizeof sin->sin_addr, AF_INET);
else
hp = 0;
if (hp)
host = hp->h_name;
else {
host = "?";
if (h_errno == TRY_AGAIN)
nflag = 1;
}
printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr));
if (sdl->sdl_alen)
ether_print(LLADDR(sdl));
else
printf("(incomplete)");
if (rtm->rtm_rmx.rmx_expire == 0)
printf(" permanent");
if (sin->sin_other & SIN_PROXY)
printf(" published (proxy only)");
if (rtm->rtm_addrs & RTA_NETMASK) {
sin = (struct sockaddr_inarp *)
(sdl->sdl_len + (char *)sdl);
if (sin->sin_addr.s_addr == 0xffffffff)
printf(" published");
if (sin->sin_len != 8)
printf("(wierd)");
}
printf("\n");
}
}
ether_print(cp)
u_char *cp;
{
printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
}
ether_aton(a, n)
char *a;
u_char *n;
{
int i, o[6];
i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o[0], &o[1], &o[2],
&o[3], &o[4], &o[5]);
if (i != 6) {
fprintf(stderr, "arp: invalid Ethernet address '%s'\n", a);
return (1);
}
for (i=0; i<6; i++)
n[i] = o[i];
return (0);
}
usage()
{
printf("usage: arp hostname\n");
printf(" arp -a [kernel] [kernel_memory]\n");
printf(" arp -d hostname\n");
printf(" arp -s hostname ether_addr [temp] [pub]\n");
printf(" arp -f filename\n");
exit(1);
}
rtmsg(cmd)
{
static int seq;
int rlen;
register struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
register char *cp = m_rtmsg.m_space;
register int l;
errno = 0;
if (cmd == RTM_DELETE)
goto doit;
bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
rtm->rtm_flags = flags;
rtm->rtm_version = RTM_VERSION;
switch (cmd) {
default:
fprintf(stderr, "arp: internal wrong cmd\n");
exit(1);
case RTM_ADD:
rtm->rtm_addrs |= RTA_GATEWAY;
rtm->rtm_rmx.rmx_expire = expire_time;
rtm->rtm_inits = RTV_EXPIRE;
rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
sin_m.sin_other = 0;
if (doing_proxy) {
if (export_only)
sin_m.sin_other = SIN_PROXY;
else {
rtm->rtm_addrs |= RTA_NETMASK;
rtm->rtm_flags &= ~RTF_HOST;
}
}
/* FALLTHROUGH */
case RTM_GET:
rtm->rtm_addrs |= RTA_DST;
}
#define NEXTADDR(w, s) \
if (rtm->rtm_addrs & (w)) { \
bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
NEXTADDR(RTA_DST, sin_m);
NEXTADDR(RTA_GATEWAY, sdl_m);
NEXTADDR(RTA_NETMASK, so_mask);
rtm->rtm_msglen = cp - (char *)&m_rtmsg;
doit:
l = rtm->rtm_msglen;
rtm->rtm_seq = ++seq;
rtm->rtm_type = cmd;
if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
if (errno != ESRCH || cmd != RTM_DELETE) {
perror("writing to routing socket");
return (-1);
}
}
do {
l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
} while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
if (l < 0)
(void) fprintf(stderr, "arp: read from routing socket: %s\n",
strerror(errno));
return (0);
}
quit(msg)
char *msg;
{
fprintf(stderr, "%s\n", msg);
exit(1);
}