e32a080e76
fix return/exit codes in some cases. Add -S which will delete any old entry first. Add "auto" in proxy case, so it finds the right interface automatically.
651 lines
15 KiB
C
651 lines
15 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 const copyright[] =
|
|
"@(#) Copyright (c) 1984, 1993\n\
|
|
The Regents of the University of California. All rights reserved.\n";
|
|
#endif /* not lint */
|
|
|
|
#ifndef lint
|
|
static char const sccsid[] = "@(#)from: arp.c 8.2 (Berkeley) 1/2/94";
|
|
static char const freebsdid[] = "$Id$";
|
|
#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/sockio.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/ioctl.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 <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <strings.h>
|
|
#include <paths.h>
|
|
|
|
void dump(u_long addr);
|
|
int delete(char *host, char *info);
|
|
void ether_print(u_char *cp);
|
|
void usage(void);
|
|
int set(int argc, char **argv);
|
|
void get(char *host);
|
|
int file(char *name);
|
|
void getsocket(void);
|
|
int ether_aton(char *a, u_char *n);
|
|
int rtmsg(int cmd);
|
|
void quit(char *msg);
|
|
int get_ether_addr(u_long ipaddr, u_char *hwaddr);
|
|
|
|
extern int errno;
|
|
static int pid;
|
|
static int nflag;
|
|
static int s = -1;
|
|
|
|
int
|
|
main(argc, argv)
|
|
int argc;
|
|
char **argv;
|
|
{
|
|
int ch;
|
|
|
|
pid = getpid();
|
|
while ((ch = getopt(argc, argv, "andfsS")) != 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':
|
|
delete(argv[2], NULL);
|
|
/* FALL THROUGH */
|
|
case 's':
|
|
if (argc < 4 || argc > 7)
|
|
usage();
|
|
exit(set(argc-2, &argv[2]) ? 1 : 0);
|
|
case 'f' :
|
|
if (argc != 3)
|
|
usage();
|
|
return (file(argv[2]));
|
|
case '?':
|
|
default:
|
|
usage();
|
|
}
|
|
if (argc != 2)
|
|
usage();
|
|
get(argv[1]);
|
|
exit(0);
|
|
}
|
|
|
|
/*
|
|
* Process a file to set standard arp entries
|
|
*/
|
|
int
|
|
file(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);
|
|
}
|
|
|
|
void
|
|
getsocket(void)
|
|
{
|
|
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
|
|
*/
|
|
int
|
|
set(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);
|
|
}
|
|
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++;
|
|
}
|
|
ea = (u_char *)LLADDR(&sdl_m);
|
|
if (doing_proxy && !strcmp(eaddr, "auto")) {
|
|
if (!get_ether_addr(sin->sin_addr.s_addr, ea)) {
|
|
return (1);
|
|
}
|
|
sdl_m.sdl_alen = 6;
|
|
} else {
|
|
if (ether_aton(eaddr, ea) == 0)
|
|
sdl_m.sdl_alen = 6;
|
|
}
|
|
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
|
|
*/
|
|
void
|
|
get(char *host)
|
|
{
|
|
struct hostent *hp;
|
|
struct sockaddr_inarp *sin = &sin_m;
|
|
|
|
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
|
|
*/
|
|
int
|
|
delete(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;
|
|
|
|
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));
|
|
return (0);
|
|
}
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* Dump the entire arp table
|
|
*/
|
|
void
|
|
dump(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");
|
|
}
|
|
}
|
|
|
|
void
|
|
ether_print(u_char *cp)
|
|
{
|
|
printf("%x:%x:%x:%x:%x:%x", cp[0], cp[1], cp[2], cp[3], cp[4], cp[5]);
|
|
}
|
|
|
|
int
|
|
ether_aton(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);
|
|
}
|
|
|
|
void
|
|
usage(void)
|
|
{
|
|
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 -S hostname ether_addr [temp] [pub]\n");
|
|
printf(" arp -f filename\n");
|
|
exit(1);
|
|
}
|
|
|
|
int
|
|
rtmsg(int 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);
|
|
}
|
|
|
|
void
|
|
quit(char *msg)
|
|
{
|
|
fprintf(stderr, "%s\n", msg);
|
|
exit(1);
|
|
}
|
|
|
|
/*
|
|
* get_ether_addr - get the hardware address of an interface on the
|
|
* the same subnet as ipaddr.
|
|
*/
|
|
#define MAX_IFS 32
|
|
|
|
int
|
|
get_ether_addr(u_long ipaddr, u_char *hwaddr)
|
|
{
|
|
struct ifreq *ifr, *ifend, *ifp;
|
|
u_long ina, mask;
|
|
struct sockaddr_dl *dla;
|
|
struct ifreq ifreq;
|
|
struct ifconf ifc;
|
|
struct ifreq ifs[MAX_IFS];
|
|
int s;
|
|
|
|
s = socket(AF_INET, SOCK_DGRAM, 0);
|
|
if (s < 0) {
|
|
perror("socket");
|
|
exit(1);
|
|
}
|
|
|
|
ifc.ifc_len = sizeof(ifs);
|
|
ifc.ifc_req = ifs;
|
|
if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
|
|
fprintf(stderr, "ioctl(SIOCGIFCONF): \n");
|
|
close(s);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Scan through looking for an interface with an Internet
|
|
* address on the same subnet as `ipaddr'.
|
|
*/
|
|
ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
|
|
for (ifr = ifc.ifc_req; ifr < ifend; ) {
|
|
if (ifr->ifr_addr.sa_family == AF_INET) {
|
|
ina = ((struct sockaddr_in *)
|
|
&ifr->ifr_addr)->sin_addr.s_addr;
|
|
strncpy(ifreq.ifr_name, ifr->ifr_name,
|
|
sizeof(ifreq.ifr_name));
|
|
/*
|
|
* Check that the interface is up,
|
|
* and not point-to-point or loopback.
|
|
*/
|
|
if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0)
|
|
continue;
|
|
if ((ifreq.ifr_flags &
|
|
(IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
|
|
IFF_LOOPBACK|IFF_NOARP))
|
|
!= (IFF_UP|IFF_BROADCAST))
|
|
goto nextif;
|
|
/*
|
|
* Get its netmask and check that it's on
|
|
* the right subnet.
|
|
*/
|
|
if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0)
|
|
continue;
|
|
mask = ((struct sockaddr_in *)
|
|
&ifreq.ifr_addr)->sin_addr.s_addr;
|
|
if ((ipaddr & mask) != (ina & mask))
|
|
goto nextif;
|
|
break;
|
|
}
|
|
nextif:
|
|
ifr = (struct ifreq *)
|
|
((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
|
|
}
|
|
|
|
if (ifr >= ifend) {
|
|
close(s);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Now scan through again looking for a link-level address
|
|
* for this interface.
|
|
*/
|
|
ifp = ifr;
|
|
for (ifr = ifc.ifc_req; ifr < ifend; ) {
|
|
if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0
|
|
&& ifr->ifr_addr.sa_family == AF_LINK) {
|
|
/*
|
|
* Found the link-level address - copy it out
|
|
*/
|
|
dla = (struct sockaddr_dl *) &ifr->ifr_addr;
|
|
memcpy(hwaddr, LLADDR(dla), dla->sdl_alen);
|
|
close (s);
|
|
printf("using interface %s for proxy with address ",
|
|
ifp->ifr_name);
|
|
ether_print(hwaddr);
|
|
printf("\n");
|
|
return dla->sdl_alen;
|
|
}
|
|
ifr = (struct ifreq *)
|
|
((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
|
|
}
|
|
return 0;
|
|
}
|