OpenWrt – Rev 4
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/*
* Emergency Access Daemon
* Copyright (C) 2008 Felix Fietkau <nbd@nbd.name>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <sys/types.h>
#include <sys/time.h>
#include <sys/select.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdbool.h>
#include <fcntl.h>
#include <signal.h>
#include <pcap.h>
#include <pcap-bpf.h>
#include <t_pwd.h>
#include <t_read.h>
#include <t_sha.h>
#include <t_defines.h>
#include <t_server.h>
#include <net/if.h>
#include "list.h"
#include "ead.h"
#include "ead-pcap.h"
#include "ead-crypt.h"
#include "libbridge.h"
#include "filter.c"
#ifdef linux
#include <linux/if_packet.h>
#endif
#define PASSWD_FILE "/etc/passwd"
#ifndef DEFAULT_IFNAME
#define DEFAULT_IFNAME "eth0"
#endif
#ifndef DEFAULT_DEVNAME
#define DEFAULT_DEVNAME "Unknown"
#endif
#define PCAP_MRU 1600
#define PCAP_TIMEOUT 200
#if EAD_DEBUGLEVEL >= 1
#define DEBUG(n, format, ...) do { \
if (EAD_DEBUGLEVEL >= n) \
fprintf(stderr, format, ##__VA_ARGS__); \
} while (0);
#else
#define DEBUG(n, format, ...) do {} while(0)
#endif
struct ead_instance {
struct list_head list;
char ifname[16];
int pid;
char id;
char bridge[16];
bool br_check;
};
static char ethmac[6] = "\x00\x13\x37\x00\x00\x00"; /* last 3 bytes will be randomized */
static pcap_t *pcap_fp = NULL;
static pcap_t *pcap_fp_rx = NULL;
static char pktbuf_b[PCAP_MRU];
static struct ead_packet *pktbuf = (struct ead_packet *)pktbuf_b;
static u16_t nid = 0xffff; /* node id */
static char username[32] = "";
static int state = EAD_TYPE_SET_USERNAME;
static const char *passwd_file = PASSWD_FILE;
static const char password[MAXPARAMLEN];
static bool child_pending = false;
static unsigned char abuf[MAXPARAMLEN + 1];
static unsigned char pwbuf[MAXPARAMLEN];
static unsigned char saltbuf[MAXSALTLEN];
static unsigned char pw_saltbuf[MAXSALTLEN];
static struct list_head instances;
static const char *dev_name = DEFAULT_DEVNAME;
static bool nonfork = false;
static struct ead_instance *instance = NULL;
static struct t_pwent tpe = {
.name = username,
.index = 1,
.password.data = pwbuf,
.password.len = 0,
.salt.data = saltbuf,
.salt.len = 0,
};
struct t_confent *tce = NULL;
static struct t_server *ts = NULL;
static struct t_num A, *B = NULL;
unsigned char *skey;
static void
set_recv_type(pcap_t *p, bool rx)
{
#ifdef PACKET_RECV_TYPE
struct sockaddr_ll sll;
struct ifreq ifr;
int mask;
int fd;
fd = pcap_get_selectable_fd(p);
if (fd < 0)
return;
if (rx)
mask = 1 << PACKET_BROADCAST;
else
mask = 0;
setsockopt(fd, SOL_PACKET, PACKET_RECV_TYPE, &mask, sizeof(mask));
#endif
}
static pcap_t *
ead_open_pcap(const char *ifname, char *errbuf, bool rx)
{
pcap_t *p;
p = pcap_create(ifname, errbuf);
if (p == NULL)
goto out;
pcap_set_snaplen(p, PCAP_MRU);
pcap_set_promisc(p, rx);
pcap_set_timeout(p, PCAP_TIMEOUT);
#ifdef HAS_PROTO_EXTENSION
pcap_set_protocol(p, (rx ? htons(ETH_P_IP) : 0));
#endif
pcap_set_buffer_size(p, (rx ? 10 : 1) * PCAP_MRU);
pcap_activate(p);
set_recv_type(p, rx);
out:
return p;
}
static void
get_random_bytes(void *ptr, int len)
{
int fd;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
perror("open");
exit(1);
}
read(fd, ptr, len);
close(fd);
}
static bool
prepare_password(void)
{
static char lbuf[1024];
unsigned char dig[SHA_DIGESTSIZE];
BigInteger x, v, n, g;
SHA1_CTX ctxt;
int ulen = strlen(username);
FILE *f;
lbuf[sizeof(lbuf) - 1] = 0;
f = fopen(passwd_file, "r");
if (!f)
return false;
while (fgets(lbuf, sizeof(lbuf) - 1, f) != NULL) {
char *str, *s2;
if (strncmp(lbuf, username, ulen) != 0)
continue;
if (lbuf[ulen] != ':')
continue;
str = &lbuf[ulen + 1];
if (strncmp(str, "$1$", 3) != 0)
continue;
s2 = strchr(str + 3, '$');
if (!s2)
continue;
if (s2 - str >= MAXSALTLEN)
continue;
strncpy((char *) pw_saltbuf, str, s2 - str);
pw_saltbuf[s2 - str] = 0;
s2 = strchr(s2, ':');
if (!s2)
continue;
*s2 = 0;
if (s2 - str >= MAXPARAMLEN)
continue;
strncpy((char *)password, str, MAXPARAMLEN);
fclose(f);
goto hash_password;
}
/* not found */
fclose(f);
return false;
hash_password:
tce = gettcid(tpe.index);
do {
t_random(tpe.password.data, SALTLEN);
} while (memcmp(saltbuf, (char *)dig, sizeof(saltbuf)) == 0);
if (saltbuf[0] == 0)
saltbuf[0] = 0xff;
n = BigIntegerFromBytes(tce->modulus.data, tce->modulus.len);
g = BigIntegerFromBytes(tce->generator.data, tce->generator.len);
v = BigIntegerFromInt(0);
SHA1Init(&ctxt);
SHA1Update(&ctxt, (unsigned char *) username, strlen(username));
SHA1Update(&ctxt, (unsigned char *) ":", 1);
SHA1Update(&ctxt, (unsigned char *) password, strlen(password));
SHA1Final(dig, &ctxt);
SHA1Init(&ctxt);
SHA1Update(&ctxt, saltbuf, tpe.salt.len);
SHA1Update(&ctxt, dig, sizeof(dig));
SHA1Final(dig, &ctxt);
/* x = H(s, H(u, ':', p)) */
x = BigIntegerFromBytes(dig, sizeof(dig));
BigIntegerModExp(v, g, x, n);
tpe.password.len = BigIntegerToBytes(v, (unsigned char *)pwbuf);
BigIntegerFree(v);
BigIntegerFree(x);
BigIntegerFree(g);
BigIntegerFree(n);
return true;
}
static u16_t
chksum(u16_t sum, const u8_t *data, u16_t len)
{
u16_t t;
const u8_t *dataptr;
const u8_t *last_byte;
dataptr = data;
last_byte = data + len - 1;
while(dataptr < last_byte) { /* At least two more bytes */
t = (dataptr[0] << 8) + dataptr[1];
sum += t;
if(sum < t) {
sum++; /* carry */
}
dataptr += 2;
}
if(dataptr == last_byte) {
t = (dataptr[0] << 8) + 0;
sum += t;
if(sum < t) {
sum++; /* carry */
}
}
/* Return sum in host byte order. */
return sum;
}
static void
ead_send_packet_clone(struct ead_packet *pkt)
{
u16_t len, sum;
memcpy(pktbuf, pkt, offsetof(struct ead_packet, msg));
memcpy(pktbuf->eh.ether_shost, ethmac, 6);
memcpy(pktbuf->eh.ether_dhost, pkt->eh.ether_shost, 6);
/* ip header */
len = sizeof(struct ead_packet) - sizeof(struct ether_header) + ntohl(pktbuf->msg.len);
pktbuf->len[0] = len >> 8;
pktbuf->len[1] = len & 0xff;
memcpy(pktbuf->srcipaddr, &pkt->msg.ip, 4);
memcpy(pktbuf->destipaddr, pkt->srcipaddr, 4);
/* ip checksum */
pktbuf->ipchksum = 0;
sum = chksum(0, (void *) &pktbuf->vhl, UIP_IPH_LEN);
if (sum == 0)
sum = 0xffff;
pktbuf->ipchksum = htons(~sum);
/* udp header */
pktbuf->srcport = pkt->destport;
pktbuf->destport = pkt->srcport;
/* udp checksum */
len -= UIP_IPH_LEN;
pktbuf->udplen = htons(len);
pktbuf->udpchksum = 0;
sum = len + UIP_PROTO_UDP;
sum = chksum(sum, (void *) &pktbuf->srcipaddr[0], 8); /* src, dest ip */
sum = chksum(sum, (void *) &pktbuf->srcport, len);
if (sum == 0)
sum = 0xffff;
pktbuf->udpchksum = htons(~sum);
pcap_sendpacket(pcap_fp, (void *) pktbuf, sizeof(struct ead_packet) + ntohl(pktbuf->msg.len));
}
static void
set_state(int nstate)
{
if (state == nstate)
return;
if (nstate < state) {
if ((nstate < EAD_TYPE_GET_PRIME) &&
(state >= EAD_TYPE_GET_PRIME)) {
t_serverclose(ts);
ts = NULL;
}
goto done;
}
switch(state) {
case EAD_TYPE_SET_USERNAME:
if (!prepare_password())
goto error;
ts = t_serveropenraw(&tpe, tce);
if (!ts)
goto error;
break;
case EAD_TYPE_GET_PRIME:
B = t_servergenexp(ts);
break;
case EAD_TYPE_SEND_A:
skey = t_servergetkey(ts, &A);
if (!skey)
goto error;
ead_set_key(skey);
break;
}
done:
state = nstate;
error:
return;
}
static bool
handle_ping(struct ead_packet *pkt, int len, int *nstate)
{
struct ead_msg *msg = &pktbuf->msg;
struct ead_msg_pong *pong = EAD_DATA(msg, pong);
int slen;
slen = strlen(dev_name);
if (slen > 1024)
slen = 1024;
msg->len = htonl(sizeof(struct ead_msg_pong) + slen);
strncpy(pong->name, dev_name, slen);
pong->name[slen] = 0;
pong->auth_type = htons(EAD_AUTH_MD5);
return true;
}
static bool
handle_set_username(struct ead_packet *pkt, int len, int *nstate)
{
struct ead_msg *msg = &pkt->msg;
struct ead_msg_user *user = EAD_DATA(msg, user);
set_state(EAD_TYPE_SET_USERNAME); /* clear old state */
strncpy(username, user->username, sizeof(username));
username[sizeof(username) - 1] = 0;
msg = &pktbuf->msg;
msg->len = 0;
*nstate = EAD_TYPE_GET_PRIME;
return true;
}
static bool
handle_get_prime(struct ead_packet *pkt, int len, int *nstate)
{
struct ead_msg *msg = &pktbuf->msg;
struct ead_msg_salt *salt = EAD_DATA(msg, salt);
msg->len = htonl(sizeof(struct ead_msg_salt));
salt->prime = tce->index - 1;
salt->len = ts->s.len;
memcpy(salt->salt, ts->s.data, ts->s.len);
memcpy(salt->ext_salt, pw_saltbuf, MAXSALTLEN);
*nstate = EAD_TYPE_SEND_A;
return true;
}
static bool
handle_send_a(struct ead_packet *pkt, int len, int *nstate)
{
struct ead_msg *msg = &pkt->msg;
struct ead_msg_number *number = EAD_DATA(msg, number);
len = ntohl(msg->len) - sizeof(struct ead_msg_number);
if (len > MAXPARAMLEN + 1)
return false;
A.len = len;
A.data = abuf;
memcpy(A.data, number->data, len);
msg = &pktbuf->msg;
number = EAD_DATA(msg, number);
msg->len = htonl(sizeof(struct ead_msg_number) + B->len);
memcpy(number->data, B->data, B->len);
*nstate = EAD_TYPE_SEND_AUTH;
return true;
}
static bool
handle_send_auth(struct ead_packet *pkt, int len, int *nstate)
{
struct ead_msg *msg = &pkt->msg;
struct ead_msg_auth *auth = EAD_DATA(msg, auth);
if (t_serververify(ts, auth->data) != 0) {
DEBUG(2, "Client authentication failed\n");
*nstate = EAD_TYPE_SET_USERNAME;
return false;
}
msg = &pktbuf->msg;
auth = EAD_DATA(msg, auth);
msg->len = htonl(sizeof(struct ead_msg_auth));
DEBUG(2, "Client authentication successful\n");
memcpy(auth->data, t_serverresponse(ts), sizeof(auth->data));
*nstate = EAD_TYPE_SEND_CMD;
return true;
}
static bool
handle_send_cmd(struct ead_packet *pkt, int len, int *nstate)
{
struct ead_msg *msg = &pkt->msg;
struct ead_msg_cmd *cmd = EAD_ENC_DATA(msg, cmd);
struct ead_msg_cmd_data *cmddata;
struct timeval tv, to, tn;
int pfd[2], fd;
fd_set fds;
pid_t pid;
bool stream = false;
int timeout;
int type;
int datalen;
datalen = ead_decrypt_message(msg) - sizeof(struct ead_msg_cmd);
if (datalen <= 0)
return false;
type = ntohs(cmd->type);
timeout = ntohs(cmd->timeout);
FD_ZERO(&fds);
cmd->data[datalen] = 0;
switch(type) {
case EAD_CMD_NORMAL:
if (pipe(pfd) < 0)
return false;
fcntl(pfd[0], F_SETFL, O_NONBLOCK | fcntl(pfd[0], F_GETFL));
child_pending = true;
pid = fork();
if (pid == 0) {
close(pfd[0]);
fd = open("/dev/null", O_RDWR);
if (fd > 0) {
dup2(fd, 0);
dup2(pfd[1], 1);
dup2(pfd[1], 2);
}
system((char *)cmd->data);
exit(0);
} else if (pid > 0) {
close(pfd[1]);
if (!timeout)
timeout = EAD_CMD_TIMEOUT;
stream = true;
break;
}
return false;
case EAD_CMD_BACKGROUND:
pid = fork();
if (pid == 0) {
/* close stdin, stdout, stderr, replace with fd to /dev/null */
fd = open("/dev/null", O_RDWR);
if (fd > 0) {
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
}
system((char *)cmd->data);
exit(0);
} else if (pid > 0) {
break;
}
return false;
default:
return false;
}
msg = &pktbuf->msg;
cmddata = EAD_ENC_DATA(msg, cmd_data);
if (stream) {
int nfds, bytes;
/* send keepalive packets every 200 ms so that the client doesn't timeout */
gettimeofday(&to, NULL);
memcpy(&tn, &to, sizeof(tn));
tv.tv_usec = PCAP_TIMEOUT * 1000;
tv.tv_sec = 0;
do {
cmddata->done = 0;
FD_SET(pfd[0], &fds);
nfds = select(pfd[0] + 1, &fds, NULL, NULL, &tv);
bytes = 0;
if (nfds > 0) {
bytes = read(pfd[0], cmddata->data, 1024);
if (bytes < 0)
bytes = 0;
}
if (!bytes && !child_pending)
break;
DEBUG(3, "Sending %d bytes of console data, type=%d, timeout=%d\n", bytes, ntohl(msg->type), timeout);
ead_encrypt_message(msg, sizeof(struct ead_msg_cmd_data) + bytes);
ead_send_packet_clone(pkt);
gettimeofday(&tn, NULL);
} while (tn.tv_sec < to.tv_sec + timeout);
if (child_pending) {
kill(pid, SIGKILL);
return false;
}
}
cmddata->done = 1;
ead_encrypt_message(msg, sizeof(struct ead_msg_cmd_data));
return true;
}
static void
parse_message(struct ead_packet *pkt, int len)
{
bool (*handler)(struct ead_packet *pkt, int len, int *nstate);
int min_len = sizeof(struct ead_packet);
int nstate = state;
int type = ntohl(pkt->msg.type);
if ((type >= EAD_TYPE_GET_PRIME) &&
(state != type))
return;
if ((type != EAD_TYPE_PING) &&
((ntohs(pkt->msg.sid) & EAD_INSTANCE_MASK) >>
EAD_INSTANCE_SHIFT) != instance->id)
return;
switch(type) {
case EAD_TYPE_PING:
handler = handle_ping;
break;
case EAD_TYPE_SET_USERNAME:
handler = handle_set_username;
min_len += sizeof(struct ead_msg_user);
break;
case EAD_TYPE_GET_PRIME:
handler = handle_get_prime;
break;
case EAD_TYPE_SEND_A:
handler = handle_send_a;
min_len += sizeof(struct ead_msg_number);
break;
case EAD_TYPE_SEND_AUTH:
handler = handle_send_auth;
min_len += sizeof(struct ead_msg_auth);
break;
case EAD_TYPE_SEND_CMD:
handler = handle_send_cmd;
min_len += sizeof(struct ead_msg_cmd) + sizeof(struct ead_msg_encrypted);
break;
default:
return;
}
if (len < min_len) {
DEBUG(2, "discarding packet: message too small\n");
return;
}
pktbuf->msg.magic = htonl(EAD_MAGIC);
pktbuf->msg.type = htonl(type + 1);
pktbuf->msg.nid = htons(nid);
pktbuf->msg.sid = pkt->msg.sid;
pktbuf->msg.len = 0;
if (handler(pkt, len, &nstate)) {
DEBUG(2, "sending response to packet type %d: %d\n", type + 1, ntohl(pktbuf->msg.len));
/* format response packet */
ead_send_packet_clone(pkt);
}
set_state(nstate);
}
static void
handle_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes)
{
struct ead_packet *pkt = (struct ead_packet *) bytes;
if (h->len < sizeof(struct ead_packet))
return;
if (pkt->eh.ether_type != htons(ETHERTYPE_IP))
return;
if (memcmp(pkt->eh.ether_dhost, "\xff\xff\xff\xff\xff\xff", 6) != 0)
return;
if (pkt->proto != UIP_PROTO_UDP)
return;
if (pkt->destport != htons(EAD_PORT))
return;
if (pkt->msg.magic != htonl(EAD_MAGIC))
return;
if (h->len < sizeof(struct ead_packet) + ntohl(pkt->msg.len))
return;
if ((pkt->msg.nid != 0xffff) &&
(pkt->msg.nid != htons(nid)))
return;
parse_message(pkt, h->len);
}
static void
ead_pcap_reopen(bool first)
{
static char errbuf[PCAP_ERRBUF_SIZE] = "";
if (pcap_fp_rx && (pcap_fp_rx != pcap_fp))
pcap_close(pcap_fp_rx);
if (pcap_fp)
pcap_close(pcap_fp);
pcap_fp_rx = NULL;
do {
if (instance->bridge[0]) {
pcap_fp_rx = ead_open_pcap(instance->bridge, errbuf, 1);
pcap_fp = ead_open_pcap(instance->ifname, errbuf, 0);
} else {
pcap_fp = ead_open_pcap(instance->ifname, errbuf, 1);
}
if (!pcap_fp_rx)
pcap_fp_rx = pcap_fp;
if (first && !pcap_fp) {
DEBUG(1, "WARNING: unable to open interface '%s'\n", instance->ifname);
first = false;
}
if (!pcap_fp)
sleep(1);
} while (!pcap_fp);
pcap_setfilter(pcap_fp_rx, &pktfilter);
}
static void
ead_pktloop(void)
{
while (1) {
if (pcap_dispatch(pcap_fp_rx, 1, handle_packet, NULL) < 0) {
ead_pcap_reopen(false);
continue;
}
}
}
static int
usage(const char *prog)
{
fprintf(stderr, "Usage: %s [<options>]\n"
"Options:\n"
"\t-B Run in background mode\n"
"\t-d <device> Set the device to listen on\n"
"\t-D <name> Set the name of the device visible to clients\n"
"\t-p <file> Set the password file for authenticating\n"
"\t-P <file> Write a pidfile\n"
"\n", prog);
return -1;
}
static void
server_handle_sigchld(int sig)
{
struct ead_instance *in;
struct list_head *p;
int pid = 0;
wait(&pid);
list_for_each(p, &instances) {
in = list_entry(p, struct ead_instance, list);
if (pid != in->pid)
continue;
in->pid = 0;
break;
}
}
static void
instance_handle_sigchld(int sig)
{
int pid = 0;
wait(&pid);
child_pending = false;
}
static void
start_server(struct ead_instance *i)
{
if (!nonfork) {
i->pid = fork();
if (i->pid != 0) {
if (i->pid < 0)
i->pid = 0;
return;
}
}
instance = i;
signal(SIGCHLD, instance_handle_sigchld);
ead_pcap_reopen(true);
ead_pktloop();
pcap_close(pcap_fp);
if (pcap_fp_rx != pcap_fp)
pcap_close(pcap_fp_rx);
exit(0);
}
static void
start_servers(bool restart)
{
struct ead_instance *in;
struct list_head *p;
list_for_each(p, &instances) {
in = list_entry(p, struct ead_instance, list);
if (in->pid > 0)
continue;
sleep(1);
start_server(in);
}
}
static void
stop_server(struct ead_instance *in, bool do_free)
{
if (in->pid > 0)
kill(in->pid, SIGKILL);
in->pid = 0;
if (do_free) {
list_del(&in->list);
free(in);
}
}
static void
server_handle_sigint(int sig)
{
struct ead_instance *in;
struct list_head *p, *tmp;
list_for_each_safe(p, tmp, &instances) {
in = list_entry(p, struct ead_instance, list);
stop_server(in, true);
}
exit(1);
}
static int
check_bridge_port(const char *br, const char *port, void *arg)
{
struct ead_instance *in;
struct list_head *p;
list_for_each(p, &instances) {
in = list_entry(p, struct ead_instance, list);
if (strcmp(in->ifname, port) != 0)
continue;
in->br_check = true;
if (strcmp(in->bridge, br) == 0)
break;
strncpy(in->bridge, br, sizeof(in->bridge));
DEBUG(2, "assigning port %s to bridge %s\n", in->ifname, in->bridge);
stop_server(in, false);
}
return 0;
}
static int
check_bridge(const char *name, void *arg)
{
br_foreach_port(name, check_bridge_port, arg);
return 0;
}
static void
check_all_interfaces(void)
{
struct ead_instance *in;
struct list_head *p;
br_foreach_bridge(check_bridge, NULL);
/* look for interfaces that are no longer part of a bridge */
list_for_each(p, &instances) {
in = list_entry(p, struct ead_instance, list);
if (in->br_check) {
in->br_check = false;
} else if (in->bridge[0]) {
DEBUG(2, "removing port %s from bridge %s\n", in->ifname, in->bridge);
in->bridge[0] = 0;
stop_server(in, false);
}
}
}
int main(int argc, char **argv)
{
struct ead_instance *in;
struct timeval tv;
const char *pidfile = NULL;
bool background = false;
int n_iface = 0;
int fd, ch;
if (argc == 1)
return usage(argv[0]);
INIT_LIST_HEAD(&instances);
while ((ch = getopt(argc, argv, "Bd:D:fhp:P:")) != -1) {
switch(ch) {
case 'B':
background = true;
break;
case 'f':
nonfork = true;
break;
case 'h':
return usage(argv[0]);
case 'd':
in = malloc(sizeof(struct ead_instance));
memset(in, 0, sizeof(struct ead_instance));
INIT_LIST_HEAD(&in->list);
strncpy(in->ifname, optarg, sizeof(in->ifname) - 1);
list_add(&in->list, &instances);
in->id = n_iface++;
break;
case 'D':
dev_name = optarg;
break;
case 'p':
passwd_file = optarg;
break;
case 'P':
pidfile = optarg;
break;
}
}
signal(SIGCHLD, server_handle_sigchld);
signal(SIGINT, server_handle_sigint);
signal(SIGTERM, server_handle_sigint);
signal(SIGKILL, server_handle_sigint);
if (!n_iface) {
fprintf(stderr, "Error: ead needs at least one interface\n");
return -1;
}
if (background) {
if (fork() > 0)
exit(0);
fd = open("/dev/null", O_RDWR);
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
}
if (pidfile) {
char pid[8];
int len;
unlink(pidfile);
fd = open(pidfile, O_CREAT|O_WRONLY|O_EXCL, 0644);
if (fd > 0) {
len = sprintf(pid, "%d\n", getpid());
write(fd, pid, len);
close(fd);
}
}
/* randomize the mac address */
get_random_bytes(ethmac + 3, 3);
nid = *(((u16_t *) ethmac) + 2);
start_servers(false);
br_init();
tv.tv_sec = 1;
tv.tv_usec = 0;
while (1) {
check_all_interfaces();
start_servers(true);
sleep(1);
}
br_shutdown();
return 0;
}