#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip_mroute.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
void __dead usage(void);
void sigexit(int);
size_t get_sysctl(const int *mib, u_int mcnt, char **buf);
void __dead
usage(void)
{
fprintf(stderr,
"mcroute [-b] [-f file] [-g group] -i ifaddr [-n timeout] -o outaddr\n"
" [-r timeout]\n"
" -b fork to background after setup\n"
" -f file print message to log file, default stdout\n"
" -g group multicast group, default 224.0.0.123\n"
" -i ifaddr multicast interface address\n"
" -n timeout expect not to receive any message until timeout\n"
" -o outaddr outgoing interface address\n"
" -r timeout receive timeout in seconds\n");
exit(2);
}
int
main(int argc, char *argv[])
{
struct vifctl vif;
struct mfcctl mfc;
struct vifinfo *vinfo;
FILE *log;
const char *errstr, *file, *group, *ifaddr, *outaddr;
char *buf;
size_t needed;
unsigned long pktin, pktout;
int value, ch, s, fd, background, norecv;
unsigned int timeout;
pid_t pid;
int mib[] = { CTL_NET, PF_INET, IPPROTO_IP, IPCTL_MRTVIF };
background = 0;
log = stdout;
file = NULL;
group = "224.0.1.123";
ifaddr = NULL;
norecv = 0;
outaddr = NULL;
timeout = 0;
while ((ch = getopt(argc, argv, "bf:g:i:n:o:r:")) != -1) {
switch (ch) {
case 'b':
background = 1;
break;
case 'f':
file = optarg;
break;
case 'g':
group = optarg;
break;
case 'i':
ifaddr = optarg;
break;
case 'n':
norecv = 1;
timeout = strtonum(optarg, 1, INT_MAX, &errstr);
if (errstr != NULL)
errx(1, "no timeout is %s: %s", errstr, optarg);
break;
case 'o':
outaddr = optarg;
break;
case 'r':
timeout = strtonum(optarg, 1, INT_MAX, &errstr);
if (errstr != NULL)
errx(1, "timeout is %s: %s", errstr, optarg);
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (ifaddr == NULL)
errx(2, "no ifaddr");
if (outaddr == NULL)
errx(2, "no outaddr");
if (argc)
usage();
if (file != NULL) {
log = fopen(file, "w");
if (log == NULL)
err(1, "fopen %s", file);
}
s = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP);
if (s == -1)
err(1, "socket");
value = 1;
if (setsockopt(s, IPPROTO_IP, MRT_INIT, &value, sizeof(value)) == -1)
err(1, "setsockopt MRT_INIT");
memset(&vif, 0, sizeof(vif));
vif.vifc_vifi = 0;
if (inet_pton(AF_INET, ifaddr, &vif.vifc_lcl_addr) == -1)
err(1, "inet_pton %s", ifaddr);
if (setsockopt(s, IPPROTO_IP, MRT_ADD_VIF, &vif, sizeof(vif)) == -1)
err(1, "setsockopt MRT_ADD_VIF %s", ifaddr);
memset(&vif, 0, sizeof(vif));
vif.vifc_vifi = 1;
if (inet_pton(AF_INET, outaddr, &vif.vifc_lcl_addr) == -1)
err(1, "inet_pton %s", outaddr);
if (setsockopt(s, IPPROTO_IP, MRT_ADD_VIF, &vif, sizeof(vif)) == -1)
err(1, "setsockopt MRT_ADD_VIF %s", outaddr);
memset(&mfc, 0, sizeof(mfc));
if (inet_pton(AF_INET, group, &mfc.mfcc_mcastgrp) == -1)
err(1, "inet_pton %s", group);
mfc.mfcc_parent = 0;
mfc.mfcc_ttls[1] = 1;
if (setsockopt(s, IPPROTO_IP, MRT_ADD_MFC, &mfc, sizeof(mfc)) == -1)
err(1, "setsockopt MRT_ADD_MFC %s", group);
if (background) {
pid = fork();
switch (pid) {
case -1:
err(1, "fork");
case 0:
fd = open("/dev/null", O_RDWR);
if (fd == -1)
err(1, "open /dev/null");
if (dup2(fd, 0) == -1)
err(1, "dup 0");
if (dup2(fd, 1) == -1)
err(1, "dup 1");
if (dup2(fd, 2) == -1)
err(1, "dup 2");
break;
default:
_exit(0);
}
}
if (timeout) {
if (norecv) {
if (signal(SIGALRM, sigexit) == SIG_ERR)
err(1, "signal SIGALRM");
}
alarm(timeout);
}
buf = NULL;
pktin = pktout = 0;
do {
struct timespec sleeptime = { 0, 10000000 };
if (nanosleep(&sleeptime, NULL) == -1)
err(1, "nanosleep");
needed = get_sysctl(mib, sizeof(mib) / sizeof(mib[0]), &buf);
for (vinfo = (struct vifinfo *)buf;
(char *)vinfo < buf + needed;
vinfo++) {
switch (vinfo->v_vifi) {
case 0:
if (pktin != vinfo->v_pkt_in) {
fprintf(log, "<<< %lu\n",
vinfo->v_pkt_in);
fflush(log);
}
pktin = vinfo->v_pkt_in;
break;
case 1:
if (pktout != vinfo->v_pkt_out) {
fprintf(log, ">>> %lu\n",
vinfo->v_pkt_out);
fflush(log);
}
pktout = vinfo->v_pkt_out;
break;
}
}
} while (pktin == 0 || pktout == 0);
free(buf);
if (norecv)
errx(1, "pktin %lu, pktout %lu", pktin, pktout);
return 0;
}
void
sigexit(int sig)
{
_exit(0);
}
size_t
get_sysctl(const int *mib, u_int mcnt, char **buf)
{
size_t needed;
while (1) {
if (sysctl(mib, mcnt, NULL, &needed, NULL, 0) == -1)
err(1, "sysctl-estimate");
if (needed == 0)
break;
if ((*buf = realloc(*buf, needed)) == NULL)
err(1, NULL);
if (sysctl(mib, mcnt, *buf, &needed, NULL, 0) == -1) {
if (errno == ENOMEM)
continue;
err(1, "sysctl");
}
break;
}
return needed;
}
