OpenBSD-4.6/usr.sbin/sasyncd/net.c
/* $OpenBSD: net.c,v 1.15 2007/01/08 15:31:01 markus Exp $ */
/*
* Copyright (c) 2005 Håkan Olsson. All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/*
* This code was written under funding by Multicom Security AB.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <signal.h>
#include <openssl/aes.h>
#include <openssl/sha.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "sasyncd.h"
#include "net.h"
struct msg {
u_int8_t *buf;
u_int32_t len;
int refcnt;
};
struct qmsg {
SIMPLEQ_ENTRY(qmsg) next;
struct msg *msg;
};
int *listeners;
AES_KEY aes_key[2];
#define AES_IV_LEN AES_BLOCK_SIZE
/* We never send (or expect to receive) messages smaller/larger than this. */
#define MSG_MINLEN 12
#define MSG_MAXLEN 4096
/* Local prototypes. */
static u_int8_t *net_read(struct syncpeer *, u_int32_t *, u_int32_t *);
static int net_set_sa(struct sockaddr *, char *, in_port_t);
static void net_check_peers(void *);
/* Pretty-print a buffer. */
void
dump_buf(int lvl, u_int8_t *b, u_int32_t len, char *title)
{
u_int32_t i, off, blen;
u_int8_t *buf;
const char def[] = "Buffer:";
if (cfgstate.verboselevel < lvl)
return;
blen = 2 * (len + len / 36) + 3 + (title ? strlen(title) : sizeof def);
if (!(buf = (u_int8_t *)calloc(1, blen)))
return;
snprintf(buf, blen, "%s\n ", title ? title : def);
off = strlen(buf);
for (i = 0; i < len; i++, off+=2) {
snprintf(buf + off, blen - off, "%02x", b[i]);
if ((i+1) % 36 == 0) {
off += 2;
snprintf(buf + off, blen - off, "\n ");
}
}
log_msg(lvl, "%s", buf);
free(buf);
}
/* Add a listening socket. */
static int
net_add_listener(struct sockaddr *sa)
{
char host[NI_MAXHOST], port[NI_MAXSERV];
int r, s;
s = socket(sa->sa_family, SOCK_STREAM, 0);
if (s < 0) {
perror("net_add_listener: socket()");
close(s);
return -1;
}
r = 1;
if (setsockopt(s, SOL_SOCKET,
cfgstate.listen_on ? SO_REUSEADDR : SO_REUSEPORT, (void *)&r,
sizeof r)) {
perror("net_add_listener: setsockopt()");
close(s);
return -1;
}
if (bind(s, sa, sa->sa_family == AF_INET ? sizeof(struct sockaddr_in) :
sizeof (struct sockaddr_in6))) {
perror("net_add_listener: bind()");
close(s);
return -1;
}
if (listen(s, 3)) {
perror("net_add_listener: listen()");
close(s);
return -1;
}
if (getnameinfo(sa, sa->sa_len, host, sizeof host, port, sizeof port,
NI_NUMERICHOST | NI_NUMERICSERV))
log_msg(3, "listening on port %u fd %d", cfgstate.listen_port,
s);
else
log_msg(3, "listening on %s port %s fd %d", host, port, s);
return s;
}
/* Allocate and fill in listeners array. */
static int
net_setup_listeners(void)
{
struct sockaddr_storage sa_storage;
struct sockaddr *sa = (struct sockaddr *)&sa_storage;
struct sockaddr_in *sin = (struct sockaddr_in *)sa;
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
struct ifaddrs *ifap = 0, *ifa;
int i, count;
/* Setup listening sockets. */
memset(&sa_storage, 0, sizeof sa_storage);
if (net_set_sa(sa, cfgstate.listen_on, cfgstate.listen_port) == 0) {
listeners = (int *)calloc(2, sizeof(int));
if (!listeners) {
perror("net_setup_listeners: calloc()");
goto errout;
}
listeners[1] = -1;
listeners[0] = net_add_listener(sa);
if (listeners[0] == -1) {
log_msg(0, "net_setup_listeners: could not find "
"listen address (%s)", cfgstate.listen_on);
goto errout;
}
return 0;
}
/*
* If net_set_sa() failed, cfgstate.listen_on is probably an
* interface name, so we should listen on all it's addresses.
*/
if (getifaddrs(&ifap) != 0) {
perror("net_setup_listeners: getifaddrs()");
goto errout;
}
/* How many addresses matches? */
for (count = 0, ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (!ifa->ifa_name || !ifa->ifa_addr ||
(ifa->ifa_addr->sa_family != AF_INET &&
ifa->ifa_addr->sa_family != AF_INET6))
continue;
if (cfgstate.listen_family &&
cfgstate.listen_family != ifa->ifa_addr->sa_family)
continue;
if (strcmp(ifa->ifa_name, cfgstate.listen_on) != 0)
continue;
count++;
}
if (!count) {
log_msg(0, "net_setup_listeners: no listeners found for %s",
cfgstate.listen_on);
goto errout;
}
/* Allocate one extra slot and set to -1, marking end of array. */
listeners = (int *)calloc(count + 1, sizeof(int));
if (!listeners) {
perror("net_setup_listeners: calloc()");
goto errout;
}
for (i = 0; i <= count; i++)
listeners[i] = -1;
/* Create listening sockets */
for (count = 0, ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (!ifa->ifa_name || !ifa->ifa_addr ||
(ifa->ifa_addr->sa_family != AF_INET &&
ifa->ifa_addr->sa_family != AF_INET6))
continue;
if (cfgstate.listen_family &&
cfgstate.listen_family != ifa->ifa_addr->sa_family)
continue;
if (strcmp(ifa->ifa_name, cfgstate.listen_on) != 0)
continue;
memset(&sa_storage, 0, sizeof sa_storage);
sa->sa_family = ifa->ifa_addr->sa_family;
switch (sa->sa_family) {
case AF_INET:
sin->sin_port = htons(cfgstate.listen_port);
sin->sin_len = sizeof *sin;
memcpy(&sin->sin_addr,
&((struct sockaddr_in *)ifa->ifa_addr)->sin_addr,
sizeof sin->sin_addr);
break;
case AF_INET6:
sin6->sin6_port = htons(cfgstate.listen_port);
sin6->sin6_len = sizeof *sin6;
memcpy(&sin6->sin6_addr,
&((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr,
sizeof sin6->sin6_addr);
break;
}
listeners[count] = net_add_listener(sa);
if (listeners[count] == -1) {
log_msg(4, "net_setup_listeners(setup): failed to "
"add listener, count = %d", count);
goto errout;
}
count++;
}
freeifaddrs(ifap);
return 0;
errout:
if (ifap)
freeifaddrs(ifap);
if (listeners) {
for (i = 0; listeners[i] != -1; i++)
close(listeners[i]);
free(listeners);
}
return -1;
}
int
net_init(void)
{
struct syncpeer *p;
if (AES_set_encrypt_key(cfgstate.sharedkey, cfgstate.sharedkey_len,
&aes_key[0]) ||
AES_set_decrypt_key(cfgstate.sharedkey, cfgstate.sharedkey_len,
&aes_key[1])) {
fprintf(stderr, "Bad AES shared key\n");
return -1;
}
if (net_setup_listeners())
return -1;
for (p = LIST_FIRST(&cfgstate.peerlist); p; p = LIST_NEXT(p, link)) {
p->socket = -1;
SIMPLEQ_INIT(&p->msgs);
}
net_check_peers(0);
return 0;
}
static void
net_enqueue(struct syncpeer *p, struct msg *m)
{
struct qmsg *qm;
if (p->socket < 0)
return;
qm = (struct qmsg *)malloc(sizeof *qm);
if (!qm) {
log_err("net_enqueue: malloc()");
return;
}
memset(qm, 0, sizeof *qm);
qm->msg = m;
m->refcnt++;
SIMPLEQ_INSERT_TAIL(&p->msgs, qm, next);
return;
}
/*
* Queue a message for transmission to a particular peer,
* or to all peers if no peer is specified.
*/
int
net_queue(struct syncpeer *p0, u_int32_t msgtype, u_int8_t *buf, u_int32_t len)
{
struct syncpeer *p = p0;
struct msg *m;
SHA_CTX ctx;
u_int8_t hash[SHA_DIGEST_LENGTH];
u_int8_t iv[AES_IV_LEN], tmp_iv[AES_IV_LEN];
u_int32_t v, padlen = 0;
int i, offset;
m = (struct msg *)calloc(1, sizeof *m);
if (!m) {
log_err("net_queue: calloc()");
free(buf);
return -1;
}
/* Generate hash */
SHA1_Init(&ctx);
SHA1_Update(&ctx, buf, len);
SHA1_Final(hash, &ctx);
dump_buf(5, hash, sizeof hash, "net_queue: computed hash");
/* Padding required? */
i = len % AES_IV_LEN;
if (i) {
u_int8_t *pbuf;
i = AES_IV_LEN - i;
pbuf = realloc(buf, len + i);
if (!pbuf) {
log_err("net_queue: realloc()");
free(buf);
free(m);
return -1;
}
padlen = i;
while (i > 0)
pbuf[len++] = (u_int8_t)i--;
buf = pbuf;
}
/* Get random IV */
for (i = 0; i <= sizeof iv - sizeof v; i += sizeof v) {
v = arc4random();
memcpy(&iv[i], &v, sizeof v);
}
dump_buf(5, iv, sizeof iv, "net_queue: IV");
memcpy(tmp_iv, iv, sizeof tmp_iv);
/* Encrypt */
dump_buf(5, buf, len, "net_queue: pre encrypt");
AES_cbc_encrypt(buf, buf, len, &aes_key[0], tmp_iv, AES_ENCRYPT);
dump_buf(5, buf, len, "net_queue: post encrypt");
/* Allocate send buffer */
m->len = len + sizeof iv + sizeof hash + 3 * sizeof(u_int32_t);
m->buf = (u_int8_t *)malloc(m->len);
if (!m->buf) {
free(m);
free(buf);
log_err("net_queue: calloc()");
return -1;
}
offset = 0;
/* Fill it (order must match parsing code in net_read()) */
v = htonl(m->len - sizeof(u_int32_t));
memcpy(m->buf + offset, &v, sizeof v);
offset += sizeof v;
v = htonl(msgtype);
memcpy(m->buf + offset, &v, sizeof v);
offset += sizeof v;
v = htonl(padlen);
memcpy(m->buf + offset, &v, sizeof v);
offset += sizeof v;
memcpy(m->buf + offset, hash, sizeof hash);
offset += sizeof hash;
memcpy(m->buf + offset, iv, sizeof iv);
offset += sizeof iv;
memcpy(m->buf + offset, buf, len);
free(buf);
if (p)
net_enqueue(p, m);
else
for (p = LIST_FIRST(&cfgstate.peerlist); p;
p = LIST_NEXT(p, link))
net_enqueue(p, m);
if (!m->refcnt) {
free(m->buf);
free(m);
}
return 0;
}
/* Set all write pending filedescriptors. */
int
net_set_pending_wfds(fd_set *fds)
{
struct syncpeer *p;
int max_fd = -1;
for (p = LIST_FIRST(&cfgstate.peerlist); p; p = LIST_NEXT(p, link))
if (p->socket > -1 && SIMPLEQ_FIRST(&p->msgs)) {
FD_SET(p->socket, fds);
if (p->socket > max_fd)
max_fd = p->socket;
}
return max_fd + 1;
}
/*
* Set readable filedescriptors. They are basically the same as for write,
* plus the listening socket.
*/
int
net_set_rfds(fd_set *fds)
{
struct syncpeer *p;
int i, max_fd = -1;
for (p = LIST_FIRST(&cfgstate.peerlist); p; p = LIST_NEXT(p, link)) {
if (p->socket > -1)
FD_SET(p->socket, fds);
if (p->socket > max_fd)
max_fd = p->socket;
}
for (i = 0; listeners[i] != -1; i++) {
FD_SET(listeners[i], fds);
if (listeners[i] > max_fd)
max_fd = listeners[i];
}
return max_fd + 1;
}
static void
net_accept(int accept_socket)
{
struct sockaddr_storage sa_storage, sa_storage2;
struct sockaddr *sa = (struct sockaddr *)&sa_storage;
struct sockaddr *sa2 = (struct sockaddr *)&sa_storage2;
struct sockaddr_in *sin, *sin2;
struct sockaddr_in6 *sin6, *sin62;
struct syncpeer *p;
socklen_t socklen;
int s, found;
/* Accept a new incoming connection */
socklen = sizeof sa_storage;
memset(&sa_storage, 0, socklen);
memset(&sa_storage2, 0, socklen);
s = accept(accept_socket, sa, &socklen);
if (s > -1) {
/* Setup the syncpeer structure */
found = 0;
for (p = LIST_FIRST(&cfgstate.peerlist); p && !found;
p = LIST_NEXT(p, link)) {
/* Match? */
if (net_set_sa(sa2, p->name, 0))
continue;
if (sa->sa_family != sa2->sa_family)
continue;
if (sa->sa_family == AF_INET) {
sin = (struct sockaddr_in *)sa;
sin2 = (struct sockaddr_in *)sa2;
if (memcmp(&sin->sin_addr, &sin2->sin_addr,
sizeof(struct in_addr)))
continue;
} else {
sin6 = (struct sockaddr_in6 *)sa;
sin62 = (struct sockaddr_in6 *)sa2;
if (memcmp(&sin6->sin6_addr, &sin62->sin6_addr,
sizeof(struct in6_addr)))
continue;
}
/* Match! */
found++;
p->socket = s;
log_msg(1, "net: peer \"%s\" connected", p->name);
if (cfgstate.runstate == MASTER)
timer_add("pfkey_snap", 2, pfkey_snapshot, p);
}
if (!found) {
log_msg(1, "net: found no matching peer for accepted "
"socket, closing.");
close(s);
}
} else
log_err("net: accept()");
}
void
net_handle_messages(fd_set *fds)
{
struct syncpeer *p;
u_int8_t *msg;
u_int32_t msgtype, msglen;
int i;
for (i = 0; listeners[i] != -1; i++)
if (FD_ISSET(listeners[i], fds))
net_accept(listeners[i]);
for (p = LIST_FIRST(&cfgstate.peerlist); p; p = LIST_NEXT(p, link)) {
if (p->socket < 0 || !FD_ISSET(p->socket, fds))
continue;
msg = net_read(p, &msgtype, &msglen);
if (!msg)
continue;
log_msg(5, "net_handle_messages: got msg type %u len %u from "
"peer %s", msgtype, msglen, p->name);
switch (msgtype) {
case MSG_SYNCCTL:
net_ctl_handle_msg(p, msg, msglen);
free(msg);
break;
case MSG_PFKEYDATA:
if (p->runstate != MASTER ||
cfgstate.runstate == MASTER) {
log_msg(1, "net: got PFKEY message from "
"non-MASTER peer");
free(msg);
if (cfgstate.runstate == MASTER)
net_ctl_send_state(p);
else
net_ctl_send_error(p, 0);
} else if (pfkey_queue_message(msg, msglen))
free(msg);
break;
default:
log_msg(0, "net: got unknown message type %u len %u "
"from peer %s", msgtype, msglen, p->name);
free(msg);
net_ctl_send_error(p, 0);
}
}
}
void
net_send_messages(fd_set *fds)
{
struct syncpeer *p;
struct qmsg *qm;
struct msg *m;
ssize_t r;
for (p = LIST_FIRST(&cfgstate.peerlist); p; p = LIST_NEXT(p, link)) {
if (p->socket < 0 || !FD_ISSET(p->socket, fds))
continue;
qm = SIMPLEQ_FIRST(&p->msgs);
if (!qm) {
/* XXX Log */
continue;
}
m = qm->msg;
log_msg(5, "net_send_messages: msg %p len %u ref %d "
"to peer %s", m, m->len, m->refcnt, p->name);
/* write message */
r = write(p->socket, m->buf, m->len);
if (r == -1) {
net_disconnect_peer(p);
log_msg(0, "net_send_messages: write() failed, "
"peer disconnected");
} else if (r < (ssize_t)m->len) {
/* retransmit later */
continue;
}
/* cleanup */
SIMPLEQ_REMOVE_HEAD(&p->msgs, next);
free(qm);
if (--m->refcnt < 1) {
log_msg(5, "net_send_messages: freeing msg %p", m);
free(m->buf);
free(m);
}
}
return;
}
void
net_disconnect_peer(struct syncpeer *p)
{
if (p->socket > -1) {
log_msg(1, "net_disconnect_peer: peer \"%s\" removed",
p->name);
close(p->socket);
}
p->socket = -1;
}
void
net_shutdown(void)
{
struct syncpeer *p;
struct qmsg *qm;
struct msg *m;
int i;
while ((p = LIST_FIRST(&cfgstate.peerlist))) {
while ((qm = SIMPLEQ_FIRST(&p->msgs))) {
SIMPLEQ_REMOVE_HEAD(&p->msgs, next);
m = qm->msg;
if (--m->refcnt < 1) {
free(m->buf);
free(m);
}
free(qm);
}
net_disconnect_peer(p);
if (p->sa)
free(p->sa);
if (p->name)
free(p->name);
LIST_REMOVE(p, link);
cfgstate.peercnt--;
free(p);
}
if (listeners) {
for (i = 0; listeners[i] != -1; i++)
close(listeners[i]);
free(listeners);
listeners = 0;
}
}
/*
* Helper functions (local) below here.
*/
static u_int8_t *
net_read(struct syncpeer *p, u_int32_t *msgtype, u_int32_t *msglen)
{
u_int8_t *msg, *blob, *rhash, *iv, hash[SHA_DIGEST_LENGTH];
u_int32_t v, blob_len, pos = 0;
int padlen = 0, offset = 0, r;
SHA_CTX ctx;
/* Read blob length */
r = read(p->socket, &v, sizeof v);
if (r != (ssize_t)sizeof v) {
if (r < 1)
net_disconnect_peer(p);
return NULL;
}
blob_len = ntohl(v);
if (blob_len < sizeof hash + AES_IV_LEN + 2 * sizeof(u_int32_t))
return NULL;
*msglen = blob_len - sizeof hash - AES_IV_LEN - 2 * sizeof(u_int32_t);
if (*msglen < MSG_MINLEN || *msglen > MSG_MAXLEN)
return NULL;
/* Read message blob */
blob = (u_int8_t *)malloc(blob_len);
if (!blob) {
log_err("net_read: malloc()");
return NULL;
}
while (blob_len > pos) {
switch (r = read(p->socket, blob + pos, blob_len - pos)) {
case -1:
if (errno == EINTR || errno == EAGAIN)
continue;
/* FALLTHROUGH */
case 0:
net_disconnect_peer(p);
free(blob);
return NULL;
/* NOTREACHED */
default:
pos += r;
}
}
offset = 0;
memcpy(&v, blob + offset, sizeof v);
*msgtype = ntohl(v);
offset += sizeof v;
if (*msgtype > MSG_MAXTYPE) {
free(blob);
return NULL;
}
memcpy(&v, blob + offset, sizeof v);
padlen = ntohl(v);
offset += sizeof v;
rhash = blob + offset;
iv = rhash + sizeof hash;
msg = (u_int8_t *)malloc(*msglen);
if (!msg) {
free(blob);
return NULL;
}
memcpy(msg, iv + AES_IV_LEN, *msglen);
dump_buf(5, rhash, sizeof hash, "net_read: got hash");
dump_buf(5, iv, AES_IV_LEN, "net_read: got IV");
dump_buf(5, msg, *msglen, "net_read: pre decrypt");
AES_cbc_encrypt(msg, msg, *msglen, &aes_key[1], iv, AES_DECRYPT);
dump_buf(5, msg, *msglen, "net_read: post decrypt");
*msglen -= padlen;
SHA1_Init(&ctx);
SHA1_Update(&ctx, msg, *msglen);
SHA1_Final(hash, &ctx);
dump_buf(5, hash, sizeof hash, "net_read: computed hash");
if (memcmp(hash, rhash, sizeof hash) != 0) {
free(blob);
log_msg(0, "net_read: got bad message (typo in shared key?)");
return NULL;
}
free(blob);
return msg;
}
static int
net_set_sa(struct sockaddr *sa, char *name, in_port_t port)
{
struct sockaddr_in *sin = (struct sockaddr_in *)sa;
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
if (!name) {
/* XXX Assume IPv4 */
sa->sa_family = AF_INET;
sin->sin_port = htons(port);
sin->sin_len = sizeof *sin;
return 0;
}
if (inet_pton(AF_INET, name, &sin->sin_addr) == 1) {
sa->sa_family = AF_INET;
sin->sin_port = htons(port);
sin->sin_len = sizeof *sin;
return 0;
}
if (inet_pton(AF_INET6, name, &sin6->sin6_addr) == 1) {
sa->sa_family = AF_INET6;
sin6->sin6_port = htons(port);
sin6->sin6_len = sizeof *sin6;
return 0;
}
return -1;
}
static void
got_sigalrm(int s)
{
return;
}
void
net_connect(void)
{
struct itimerval iv;
struct syncpeer *p;
signal(SIGALRM, got_sigalrm);
memset(&iv, 0, sizeof iv);
iv.it_value.tv_sec = 5;
iv.it_interval.tv_sec = 5;
setitimer(ITIMER_REAL, &iv, NULL);
for (p = LIST_FIRST(&cfgstate.peerlist); p; p = LIST_NEXT(p, link)) {
if (p->socket > -1)
continue;
if (!p->sa) {
p->sa = (void *)calloc(1,
sizeof(struct sockaddr_storage));
if (!p->sa)
return;
if (net_set_sa(p->sa, p->name, cfgstate.listen_port))
continue;
}
p->socket = socket(p->sa->sa_family, SOCK_STREAM, 0);
if (p->socket < 0) {
log_err("peer \"%s\": socket()", p->name);
continue;
}
if (connect(p->socket, p->sa, p->sa->sa_len)) {
log_msg(1, "net_connect: peer \"%s\" not ready yet",
p->name);
net_disconnect_peer(p);
continue;
}
if (net_ctl_send_state(p)) {
log_msg(0, "net_connect: peer \"%s\" failed", p->name);
net_disconnect_peer(p);
continue;
}
log_msg(1, "net_connect: peer \"%s\" connected, fd %d",
p->name, p->socket);
/* Schedule a pfkey sync to the newly connected peer. */
if (cfgstate.runstate == MASTER)
timer_add("pfkey_snapshot", 2, pfkey_snapshot, p);
}
timerclear(&iv.it_value);
timerclear(&iv.it_interval);
setitimer(ITIMER_REAL, &iv, NULL);
signal(SIGALRM, SIG_IGN);
return;
}
static void
net_check_peers(void *arg)
{
net_connect();
(void)timer_add("peer recheck", 600, net_check_peers, 0);
}