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|
/* $OpenBSD: arp.c,v 1.40 2007/08/24 13:12:16 claudio Exp $ */
/* $NetBSD: arp.c,v 1.12 1995/04/24 13:25:18 cgd 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.
*/
/*
* 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 <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <paths.h>
#include <unistd.h>
int delete(const char *, const char *);
void search(in_addr_t addr, void (*action)(struct sockaddr_dl *sdl,
struct sockaddr_inarp *sin, struct rt_msghdr *rtm));
void print_entry(struct sockaddr_dl *sdl,
struct sockaddr_inarp *sin, struct rt_msghdr *rtm);
void nuke_entry(struct sockaddr_dl *sdl,
struct sockaddr_inarp *sin, struct rt_msghdr *rtm);
void ether_print(const char *);
int file(char *);
int get(const char *);
int getinetaddr(const char *, struct in_addr *);
void getsocket(void);
int rtmsg(int);
int set(int, char **);
void usage(void);
static pid_t pid;
static int replace; /* replace entries when adding */
static int nflag; /* no reverse dns lookups */
static int aflag; /* do it for all entries */
static int s = -1;
extern int h_errno;
/* ROUNDUP() is nasty, but it is identical to what's in the kernel. */
#define ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
/* which function we're supposed to do */
#define F_GET 1
#define F_SET 2
#define F_FILESET 3
#define F_DELETE 4
int
main(int argc, char *argv[])
{
int ch, func = 0, rtn;
pid = getpid();
opterr = 0;
while ((ch = getopt(argc, argv, "andsFf")) != -1) {
switch (ch) {
case 'a':
aflag = 1;
break;
case 'n':
nflag = 1;
break;
case 'd':
if (func)
usage();
func = F_DELETE;
break;
case 's':
if (func)
usage();
func = F_SET;
break;
case 'F':
replace = 1;
break;
case 'f':
if (func)
usage();
func = F_FILESET;
break;
default:
usage();
break;
}
}
argc -= optind;
argv += optind;
if (!func)
func = F_GET;
rtn = 0;
switch (func) {
case F_GET:
if (aflag && argc == 0)
search(0, print_entry);
else if (!aflag && argc == 1)
rtn = get(argv[0]);
else
usage();
break;
case F_SET:
if (argc < 2 || argc > 5)
usage();
if (replace)
delete(argv[0], NULL);
rtn = set(argc, argv) ? 1 : 0;
break;
case F_DELETE:
if (aflag && argc == 0)
search(0, nuke_entry);
else if (!aflag && argc == 1)
rtn = delete(argv[0], argv[1]);
else
usage();
break;
case F_FILESET:
if (argc != 1)
usage();
rtn = file(argv[0]);
break;
}
return (rtn);
}
/*
* Process a file to set standard arp entries
*/
int
file(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, sizeof(line), 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 (replace)
delete(arg[0], NULL);
if (set(i, args))
retval = 1;
}
fclose(fp);
return (retval);
}
void
getsocket(void)
{
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(int argc, char *argv[])
{
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
struct rt_msghdr *rtm;
char *eaddr = argv[1], *host = argv[0];
struct ether_addr *ea;
sin = &sin_m;
rtm = &(m_rtmsg.m_rtm);
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);
ea = ether_aton(eaddr);
if (ea == NULL)
errx(1, "invalid ethernet address: %s", eaddr);
memcpy(LLADDR(&sdl_m), ea, sizeof(*ea));
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;
if (flags & RTF_PERMANENT_ARP) {
/* temp or permanent, not both */
usage();
return (0);
}
} else if (strncmp(argv[0], "pub", 3) == 0) {
flags |= RTF_ANNOUNCE;
doing_proxy = SIN_PROXY;
} else if (strncmp(argv[0], "permanent", 9) == 0) {
flags |= RTF_PERMANENT_ARP;
if (expire_time != 0) {
/* temp or permanent, not both */
usage();
return (0);
}
} 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) {
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_CARP:
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
*/
int
get(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);
search(sin->sin_addr.s_addr, print_entry);
if (found_entry == 0) {
printf("%s (%s) -- no entry\n", host, inet_ntoa(sin->sin_addr));
return (1);
}
return (0);
}
/*
* Delete an arp entry
*/
int
delete(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_CARP:
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) {
printf("cannot locate %s\n", host);
return (1);
}
if (rtmsg(RTM_DELETE))
return (1);
printf("%s (%s) deleted\n", host, inet_ntoa(sin->sin_addr));
return (0);
}
/*
* Search the entire arp table, and do some action on matching entries.
*/
void
search(in_addr_t addr, void (*action)(struct sockaddr_dl *sdl,
struct sockaddr_inarp *sin, struct rt_msghdr *rtm))
{
int mib[6];
size_t needed;
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;
if (rtm->rtm_version != RTM_VERSION)
continue;
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;
}
(*action)(sdl, sin, rtm);
}
free(buf);
}
/*
* Display an arp entry
*/
void
print_entry(struct sockaddr_dl *sdl, struct sockaddr_inarp *sin,
struct rt_msghdr *rtm)
{
char ifname[IFNAMSIZ], *host;
struct hostent *hp;
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 (if_indextoname(sdl->sdl_index, ifname) != NULL)
printf(" on %s", ifname);
if (rtm->rtm_flags & RTF_PERMANENT_ARP)
printf(" permanent");
if (rtm->rtm_rmx.rmx_expire == 0)
printf(" static");
if (sin->sin_other & SIN_PROXY)
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)
printf(" published");
if (sin->sin_len != 8)
printf("(weird %d)", sin->sin_len);
}
printf("\n");
}
/*
* Nuke an arp entry
*/
void
nuke_entry(struct sockaddr_dl *sdl, struct sockaddr_inarp *sin,
struct rt_msghdr *rtm)
{
char ip[20];
strlcpy(ip, inet_ntoa(sin->sin_addr), sizeof(ip));
delete(ip, NULL);
}
void
ether_print(const char *scp)
{
const u_char *cp = (u_char *)scp;
printf("%02x:%02x:%02x:%02x:%02x:%02x",
cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
}
void
usage(void)
{
fprintf(stderr, "usage: arp [-adn] hostname\n");
fprintf(stderr, "usage: arp [-F] [-f file] -s hostname ether_addr "
"[temp | permanent] [pub]\n");
exit(1);
}
int
rtmsg(int cmd)
{
static int seq;
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;
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)) { \
memcpy(cp, &s, sizeof(s)); \
cp += ROUNDUP(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 (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(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);
}
memcpy(inap, hp->h_addr, sizeof(*inap));
return (0);
}
|