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NetBSD/usr.sbin/arp/arp.c

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/* $NetBSD: arp.c,v 1.38 2003/08/07 11:25:12 agc Exp $ */
/*
* 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. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1984, 1993\n\
The Regents of the University of California. All rights reserved.\n");
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95";
#else
__RCSID("$NetBSD: arp.c,v 1.38 2003/08/07 11:25:12 agc Exp $");
#endif
#endif /* not lint */
/*
* arp - display, set, and delete arp table entries
*/
/* Roundup the same way rt_xaddrs does */
#define ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_ether.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_inarp.h>
#include <arpa/inet.h>
#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ifaddrs.h>
int delete __P((const char *, const char *));
void dump __P((u_long));
void delete_all __P((void));
void sdl_print __P((const struct sockaddr_dl *));
int getifname __P((u_int16_t, char *, size_t));
int atosdl __P((const char *s, struct sockaddr_dl *sdl));
int file __P((char *));
void get __P((const char *));
int getinetaddr __P((const char *, struct in_addr *));
void getsocket __P((void));
int main __P((int, char **));
int rtmsg __P((int));
int set __P((int, char **));
void usage __P((void));
static int pid;
static int aflag, nflag, vflag;
static int s = -1;
static struct ifaddrs* ifaddrs = NULL;
int
main(argc, argv)
int argc;
char **argv;
{
int ch;
int op = 0;
setprogname(argv[0]);
pid = getpid();
while ((ch = getopt(argc, argv, "andsfv")) != -1)
switch((char)ch) {
case 'a':
aflag = 1;
break;
case 'd':
case 's':
case 'f':
if (op)
usage();
op = ch;
break;
case 'n':
nflag = 1;
break;
case 'v':
vflag = 1;
break;
default:
usage();
}
argc -= optind;
argv += optind;
if (!op && aflag)
op = 'a';
switch((char)op) {
case 'a':
dump(0);
break;
case 'd':
if (aflag && argc == 0)
delete_all();
else {
if (aflag || argc < 1 || argc > 2)
usage();
(void)delete(argv[0], argv[1]);
}
break;
case 's':
if (argc < 2 || argc > 5)
usage();
return (set(argc, argv) ? 1 : 0);
case 'f':
if (argc != 1)
usage();
return (file(argv[0]));
default:
if (argc != 1)
usage();
get(argv[0]);
break;
}
return (0);
}
/*
* Process a file to set standard arp entries
*/
int
file(name)
char *name;
{
char line[100], arg[5][50], *args[5];
int i, retval;
FILE *fp;
if ((fp = fopen(name, "r")) == NULL)
err(1, "cannot open %s", name);
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, "%49s %49s %49s %49s %49s",
arg[0], arg[1], arg[2], arg[3], arg[4]);
if (i < 2) {
warnx("bad line: %s", line);
retval = 1;
continue;
}
if (set(i, args))
retval = 1;
}
fclose(fp);
return (retval);
}
void
getsocket()
{
if (s >= 0)
return;
s = socket(PF_ROUTE, SOCK_RAW, 0);
if (s < 0)
err(1, "socket");
}
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
*/
int
set(argc, argv)
int argc;
char **argv;
{
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
struct rt_msghdr *rtm;
char *host = argv[0], *eaddr;
int rval;
sin = &sin_m;
rtm = &(m_rtmsg.m_rtm);
eaddr = argv[1];
getsocket();
argc -= 2;
argv += 2;
sdl_m = blank_sdl; /* struct copy */
sin_m = blank_sin; /* struct copy */
if (getinetaddr(host, &sin->sin_addr) == -1)
return (1);
if (atosdl(eaddr, &sdl_m))
warnx("invalid link-level address '%s'", eaddr);
doing_proxy = flags = export_only = expire_time = 0;
while (argc-- > 0) {
if (strncmp(argv[0], "temp", 4) == 0) {
struct timeval time;
(void)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) {
(void)printf(
"%s: Sending trailers is no longer supported\n",
host);
}
argv++;
}
tryagain:
if (rtmsg(RTM_GET) < 0) {
warn("%s", host);
return (1);
}
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(ROUNDUP(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: case IFT_ARCNET:
goto overwrite;
}
if (doing_proxy == 0) {
(void)printf("set: can only proxy for %s\n", host);
return (1);
}
if (sin_m.sin_other & SIN_PROXY) {
(void)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) {
(void)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;
rval = rtmsg(RTM_ADD);
if (vflag)
(void)printf("%s (%s) added\n", host, eaddr);
return (rval);
}
/*
* Display an individual arp entry
*/
void
get(host)
const char *host;
{
struct sockaddr_inarp *sin;
sin = &sin_m;
sin_m = blank_sin; /* struct copy */
if (getinetaddr(host, &sin->sin_addr) == -1)
exit(1);
dump(sin->sin_addr.s_addr);
if (found_entry == 0) {
(void)printf("%s (%s) -- no entry\n", host,
inet_ntoa(sin->sin_addr));
exit(1);
}
}
/*
* Delete an arp entry
*/
int
delete(host, info)
const char *host;
const char *info;
{
struct sockaddr_inarp *sin;
struct rt_msghdr *rtm;
struct sockaddr_dl *sdl;
sin = &sin_m;
rtm = &m_rtmsg.m_rtm;
if (info && strncmp(info, "pro", 3) )
export_only = 1;
getsocket();
sin_m = blank_sin; /* struct copy */
if (getinetaddr(host, &sin->sin_addr) == -1)
return (1);
tryagain:
if (rtmsg(RTM_GET) < 0) {
warn("%s", host);
return (1);
}
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(ROUNDUP(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: case IFT_ARCNET:
goto delete;
}
}
if (sin_m.sin_other & SIN_PROXY) {
warnx("delete: can't locate %s", host);
return (1);
} else {
sin_m.sin_other = SIN_PROXY;
goto tryagain;
}
delete:
if (sdl->sdl_family != AF_LINK) {
(void)printf("cannot locate %s\n", host);
return (1);
}
if (rtmsg(RTM_DELETE))
return (1);
if (vflag)
(void)printf("%s (%s) deleted\n", host,
inet_ntoa(sin->sin_addr));
return (0);
}
/*
* Dump the entire arp table
*/
void
dump(addr)
u_long addr;
{
int mib[6];
size_t needed;
char ifname[IFNAMSIZ];
char *host, *lim, *buf, *next;
struct rt_msghdr *rtm;
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
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)
err(1, "route-sysctl-estimate");
if (needed == 0)
return;
if ((buf = malloc(needed)) == NULL)
err(1, "malloc");
if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
err(1, "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 *)
(ROUNDUP(sin->sin_len) + (char *)sin);
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 = NULL;
host = hp ? hp->h_name : "?";
(void)printf("%s (%s) at ", host, inet_ntoa(sin->sin_addr));
if (sdl->sdl_alen)
sdl_print(sdl);
else
(void)printf("(incomplete)");
if (sdl->sdl_index) {
if (getifname(sdl->sdl_index, ifname, sizeof(ifname)) == 0)
printf(" on %s", ifname);
}
if (rtm->rtm_rmx.rmx_expire == 0)
(void)printf(" permanent");
if (sin->sin_other & SIN_PROXY)
(void)printf(" published (proxy only)");
if (rtm->rtm_addrs & RTA_NETMASK) {
sin = (struct sockaddr_inarp *)
(ROUNDUP(sdl->sdl_len) + (char *)sdl);
if (sin->sin_addr.s_addr == 0xffffffff)
(void)printf(" published");
if (sin->sin_len != 8)
(void)printf("(weird)");
}
(void)printf("\n");
}
}
/*
* Delete the entire arp table
*/
void
delete_all(void)
{
int mib[6];
size_t needed;
char addr[sizeof("000.000.000.000\0")];
char *lim, *buf, *next;
struct rt_msghdr *rtm;
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
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)
err(1, "route-sysctl-estimate");
if (needed == 0)
return;
if ((buf = malloc(needed)) == NULL)
err(1, "malloc");
if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
err(1, "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 *)
(ROUNDUP(sin->sin_len) + (char *)sin);
snprintf(addr, sizeof(addr), "%s", inet_ntoa(sin->sin_addr));
delete(addr, NULL);
}
}
void
sdl_print(sdl)
const struct sockaddr_dl *sdl;
{
char hbuf[NI_MAXHOST];
if (getnameinfo((struct sockaddr *)sdl, sdl->sdl_len,
hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0)
printf("<invalid>");
else
printf("%s", hbuf);
}
int
atosdl(s, sdl)
const char *s;
struct sockaddr_dl *sdl;
{
int i;
long b;
caddr_t endp;
caddr_t p;
char *t, *r;
p = LLADDR(sdl);
endp = ((caddr_t)sdl) + sdl->sdl_len;
i = 0;
b = strtol(s, &t, 16);
if (t == s)
return 1;
*p++ = b;
++i;
while ((p < endp) && (*t++ == ':')) {
b = strtol(t, &r, 16);
if (r == t)
break;
*p++ = b;
++i;
t = r;
}
sdl->sdl_alen = i;
return 0;
}
void
usage()
{
const char *progname;
progname = getprogname();
(void)fprintf(stderr, "usage: %s [-n] hostname\n", progname);
(void)fprintf(stderr, "usage: %s [-n] -a\n", progname);
(void)fprintf(stderr, "usage: %s -d [-a|hostname]\n", progname);
(void)fprintf(stderr,
"usage: %s -s hostname ether_addr [temp] [pub]\n", progname);
(void)fprintf(stderr, "usage: %s -f filename\n", progname);
exit(1);
}
int
rtmsg(cmd)
int cmd;
{
static int seq;
int rlen;
struct rt_msghdr *rtm;
char *cp;
int l;
rtm = &m_rtmsg.m_rtm;
cp = m_rtmsg.m_space;
errno = 0;
if (cmd == RTM_DELETE)
goto doit;
(void)memset(&m_rtmsg, 0, sizeof(m_rtmsg));
rtm->rtm_flags = flags;
rtm->rtm_version = RTM_VERSION;
switch (cmd) {
default:
errx(1, "internal wrong cmd");
/*NOTREACHED*/
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)) { \
(void)memcpy(cp, &s, ((struct sockaddr *)&s)->sa_len); \
cp += ROUNDUP(((struct sockaddr *)&s)->sa_len); \
}
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) {
warn("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)
warn("read from routing socket");
return (0);
}
int
getinetaddr(host, inap)
const char *host;
struct in_addr *inap;
{
struct hostent *hp;
if (inet_aton(host, inap) == 1)
return (0);
if ((hp = gethostbyname(host)) == NULL) {
warnx("%s: %s", host, hstrerror(h_errno));
return (-1);
}
(void)memcpy(inap, hp->h_addr, sizeof(*inap));
return (0);
}
int
getifname(ifindex, ifname, l)
u_int16_t ifindex;
char* ifname;
size_t l;
{
int i;
struct ifaddrs *addr;
const struct sockaddr_dl *sdl = NULL;
if (ifaddrs == NULL) {
i = getifaddrs(&ifaddrs);
if (i != 0)
err(1, "getifaddrs");
}
for (addr = ifaddrs; addr; addr = addr->ifa_next) {
if (addr->ifa_addr == NULL ||
addr->ifa_addr->sa_family != AF_LINK)
continue;
sdl = (const struct sockaddr_dl *) addr->ifa_addr;
if (sdl && sdl->sdl_index == ifindex) {
(void) strlcpy(ifname, addr->ifa_name, l);
return 0;
}
}
return -1;
}
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