branch: master
mqttd.c
23699 bytesRaw
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "first.h"
/* Function
*
* Accepts a TCP connection on a custom port (IPv4 or IPv6). Speaks MQTT.
*
* Read commands from FILE (set with --config). The commands control how to
* act and is reset to defaults each client TCP connect.
*
*/
/* based on sockfilt.c */
#define MQTT_MSG_CONNECT 0x10
#define MQTT_MSG_CONNACK 0x20
#define MQTT_MSG_PUBLISH 0x30
/* #define MQTT_MSG_PUBACK 0x40 */
#define MQTT_MSG_SUBSCRIBE 0x82
#define MQTT_MSG_SUBACK 0x90
#define MQTT_MSG_DISCONNECT 0xe0
struct mqttd_configurable {
int testnum;
unsigned char version; /* initial version byte in the request must match
this */
bool publish_before_suback;
bool short_publish;
bool excessive_remaining;
unsigned char error_connack;
unsigned char remlen_connack;
};
#define REQUEST_DUMP "server.input"
#define CONFIG_VERSION 5
static struct mqttd_configurable m_config;
static void mqttd_resetdefaults(void)
{
logmsg("Reset to defaults");
m_config.version = CONFIG_VERSION;
m_config.publish_before_suback = FALSE;
m_config.short_publish = FALSE;
m_config.excessive_remaining = FALSE;
m_config.error_connack = 0;
m_config.remlen_connack = 0;
m_config.testnum = 0;
}
static void mqttd_getconfig(void)
{
FILE *fp = curlx_fopen(configfile, FOPEN_READTEXT);
mqttd_resetdefaults();
if(fp) {
char buffer[512];
logmsg("parse config file");
while(fgets(buffer, sizeof(buffer), fp)) {
char key[32];
char value[32];
const char *pval;
curl_off_t num;
if(sscanf(buffer, "%31s %31s", key, value) == 2) {
if(!strcmp(key, "version")) {
pval = value;
if(!curlx_str_number(&pval, &num, 0xff)) {
m_config.version = (unsigned char)num;
logmsg("version [%d] set", m_config.version);
}
}
else if(!strcmp(key, "PUBLISH-before-SUBACK")) {
logmsg("PUBLISH-before-SUBACK set");
m_config.publish_before_suback = TRUE;
}
else if(!strcmp(key, "short-PUBLISH")) {
logmsg("short-PUBLISH set");
m_config.short_publish = TRUE;
}
else if(!strcmp(key, "error-CONNACK")) {
pval = value;
if(!curlx_str_number(&pval, &num, 0xff)) {
m_config.error_connack = (unsigned char)num;
logmsg("error-CONNACK = %d", m_config.error_connack);
}
}
else if(!strcmp(key, "remlen-CONNACK")) {
pval = value;
if(!curlx_str_number(&pval, &num, 0xff)) {
m_config.remlen_connack = (unsigned char)num;
logmsg("remlen-CONNACK = %d", m_config.remlen_connack);
}
}
else if(!strcmp(key, "Testnum")) {
pval = value;
if(!curlx_str_number(&pval, &num, INT_MAX)) {
m_config.testnum = (int)num;
logmsg("testnum = %d", m_config.testnum);
}
}
else if(!strcmp(key, "excessive-remaining")) {
logmsg("excessive-remaining set");
m_config.excessive_remaining = TRUE;
}
}
}
curlx_fclose(fp);
}
else {
logmsg("No config file '%s' to read", configfile);
}
}
typedef enum {
FROM_CLIENT,
FROM_SERVER
} mqttdir;
static void logprotocol(mqttdir dir,
const char *prefix, size_t remlen,
FILE *output,
const unsigned char *buffer, ssize_t len)
{
char data[12000] = "";
ssize_t i;
const unsigned char *ptr = buffer;
char *optr = data;
int left = sizeof(data);
for(i = 0; i < len && (left >= 0); i++) {
snprintf(optr, left, "%02x", ptr[i]);
optr += 2;
left -= 2;
}
fprintf(output, "%s %s %x %s\n",
dir == FROM_CLIENT ? "client" : "server",
prefix, (int)remlen, data);
}
/* return 0 on success */
static int connack(FILE *dump, curl_socket_t fd)
{
unsigned char packet[] = {
MQTT_MSG_CONNACK, 0x02,
0x00, 0x00
};
ssize_t rc;
if(m_config.remlen_connack)
packet[1] = m_config.remlen_connack;
packet[3] = m_config.error_connack;
rc = swrite(fd, packet, sizeof(packet));
if(rc > 0) {
logmsg("WROTE %zd bytes [CONNACK]", rc);
loghex(packet, rc);
logprotocol(FROM_SERVER, "CONNACK", packet[1], dump,
packet, sizeof(packet));
}
if(rc == sizeof(packet)) {
return 0;
}
return 1;
}
/* return 0 on success */
static int suback(FILE *dump, curl_socket_t fd, unsigned short packetid)
{
unsigned char packet[] = {
MQTT_MSG_SUBACK, 0x03,
0, 0, /* filled in below */
0x00
};
ssize_t rc;
packet[2] = (unsigned char)(packetid >> 8);
packet[3] = (unsigned char)(packetid & 0xff);
rc = swrite(fd, packet, sizeof(packet));
if(rc == sizeof(packet)) {
logmsg("WROTE %zd bytes [SUBACK]", rc);
loghex(packet, rc);
logprotocol(FROM_SERVER, "SUBACK", 3, dump, packet, rc);
return 0;
}
return 1;
}
#ifdef QOS
/* return 0 on success */
static int puback(FILE *dump, curl_socket_t fd, unsigned short packetid)
{
unsigned char packet[] = {
MQTT_MSG_PUBACK, 0x00,
0, 0 /* filled in below */
};
ssize_t rc;
packet[2] = (unsigned char)(packetid >> 8);
packet[3] = (unsigned char)(packetid & 0xff);
rc = swrite(fd, packet, sizeof(packet));
if(rc == sizeof(packet)) {
logmsg("WROTE %zd bytes [PUBACK]", rc);
loghex(packet, rc);
logprotocol(FROM_SERVER, dump, packet, rc);
return 0;
}
logmsg("Failed sending [PUBACK]");
return 1;
}
#endif
/* return 0 on success */
static int disconnect(FILE *dump, curl_socket_t fd)
{
unsigned char packet[] = {
MQTT_MSG_DISCONNECT, 0x00,
};
ssize_t rc = swrite(fd, packet, sizeof(packet));
if(rc == sizeof(packet)) {
logmsg("WROTE %zd bytes [DISCONNECT]", rc);
loghex(packet, rc);
logprotocol(FROM_SERVER, "DISCONNECT", 0, dump, packet, rc);
return 0;
}
logmsg("Failed sending [DISCONNECT]");
return 1;
}
/*
do
encodedByte = X MOD 128
X = X DIV 128
// if there are more data to encode, set the top bit of this byte
if ( X > 0 )
encodedByte = encodedByte OR 128
endif
'output' encodedByte
while ( X > 0 )
*/
/* return number of bytes used */
static size_t encode_length(size_t packetlen,
unsigned char *remlength) /* 4 bytes */
{
size_t bytes = 0;
unsigned char encode;
do {
encode = packetlen % 0x80;
packetlen /= 0x80;
if(packetlen)
encode |= 0x80;
remlength[bytes++] = encode;
if(bytes > 3) {
logmsg("too large packet!");
return 0;
}
} while(packetlen);
return bytes;
}
static size_t decode_length(const unsigned char *buffer,
size_t buflen, size_t *lenbytes)
{
size_t len = 0;
size_t mult = 1;
size_t i;
unsigned char encoded = 0x80;
for(i = 0; (i < buflen) && (encoded & 0x80); i++) {
encoded = buffer[i];
len += (encoded & 0x7f) * mult;
mult *= 0x80;
}
if(lenbytes)
*lenbytes = i;
return len;
}
/* return 0 on success */
static int publish(FILE *dump,
curl_socket_t fd, unsigned short packetid,
char *topic, const char *payload, size_t payloadlen)
{
size_t topiclen = strlen(topic);
unsigned char *packet;
size_t payloadindex;
size_t remaininglength = topiclen + 2 + payloadlen;
size_t packetlen;
size_t sendamount;
ssize_t rc;
unsigned char rembuffer[4];
size_t encodedlen;
if(m_config.excessive_remaining) {
/* manually set illegal remaining length */
rembuffer[0] = 0xff;
rembuffer[1] = 0xff;
rembuffer[2] = 0xff;
rembuffer[3] = 0x80; /* maximum allowed here by spec is 0x7f */
encodedlen = 4;
}
else
encodedlen = encode_length(remaininglength, rembuffer);
/* one packet type byte (possibly two more for packetid) */
packetlen = remaininglength + encodedlen + 1;
packet = malloc(packetlen);
if(!packet)
return 1;
packet[0] = MQTT_MSG_PUBLISH;
memcpy(&packet[1], rembuffer, encodedlen);
(void)packetid;
/* packet_id if QoS is set */
packet[1 + encodedlen] = (unsigned char)(topiclen >> 8);
packet[2 + encodedlen] = (unsigned char)(topiclen & 0xff);
/* NOLINTNEXTLINE(bugprone-not-null-terminated-result) */
memcpy(&packet[3 + encodedlen], topic, topiclen);
payloadindex = 3 + topiclen + encodedlen;
memcpy(&packet[payloadindex], payload, payloadlen);
sendamount = packetlen;
if(m_config.short_publish)
sendamount -= 2;
rc = swrite(fd, packet, sendamount);
if(rc > 0) {
logmsg("WROTE %zd bytes [PUBLISH]", rc);
loghex(packet, rc);
logprotocol(FROM_SERVER, "PUBLISH", remaininglength, dump, packet, rc);
}
free(packet);
if((size_t)rc == packetlen)
return 0;
return 1;
}
#define MAX_TOPIC_LENGTH 65535
#define MAX_CLIENT_ID_LENGTH 32
static char topic[MAX_TOPIC_LENGTH + 1];
static int fixedheader(curl_socket_t fd,
unsigned char *bytep,
size_t *remaining_lengthp,
size_t *remaining_length_bytesp)
{
/* get the fixed header */
unsigned char buffer[10];
/* get the first two bytes */
ssize_t rc = sread(fd, buffer, 2);
size_t i;
if(rc < 2) {
logmsg("READ %zd bytes [SHORT!]", rc);
return 1; /* fail */
}
logmsg("READ %zd bytes", rc);
loghex(buffer, rc);
*bytep = buffer[0];
/* if the length byte has the top bit set, get the next one too */
i = 1;
while(buffer[i] & 0x80) {
i++;
rc = sread(fd, &buffer[i], 1);
if(rc != 1) {
logmsg("Remaining Length broken");
return 1;
}
}
*remaining_lengthp = decode_length(&buffer[1], i, remaining_length_bytesp);
logmsg("Remaining Length: %zu [%zu bytes]", *remaining_lengthp,
*remaining_length_bytesp);
return 0;
}
static curl_socket_t mqttit(curl_socket_t fd)
{
size_t buff_size = 10 * 1024;
unsigned char *buffer = NULL;
ssize_t rc;
unsigned char byte;
unsigned short packet_id;
size_t payload_len;
size_t client_id_length;
size_t topic_len;
size_t remaining_length = 0;
size_t bytes = 0; /* remaining length field size in bytes */
char client_id[MAX_CLIENT_ID_LENGTH];
long testno;
FILE *stream = NULL;
FILE *dump;
char dumpfile[256];
static const char protocol[7] = {
0x00, 0x04, /* protocol length */
'M','Q','T','T', /* protocol name */
0x04 /* protocol level */
};
snprintf(dumpfile, sizeof(dumpfile), "%s/%s", logdir, REQUEST_DUMP);
dump = curlx_fopen(dumpfile, "ab");
if(!dump)
goto end;
mqttd_getconfig();
testno = m_config.testnum;
if(testno)
logmsg("Found test number %ld", testno);
buffer = malloc(buff_size);
if(!buffer) {
logmsg("Out of memory, unable to allocate buffer");
goto end;
}
memset(buffer, 0, buff_size);
do {
unsigned char usr_flag = 0x80;
unsigned char passwd_flag = 0x40;
unsigned char conn_flags;
const size_t client_id_offset = 12;
size_t start_usr;
size_t start_passwd;
/* get the fixed header */
rc = fixedheader(fd, &byte, &remaining_length, &bytes);
if(rc)
break;
if(remaining_length >= buff_size) {
unsigned char *newbuffer;
buff_size = remaining_length;
newbuffer = realloc(buffer, buff_size);
if(!newbuffer) {
logmsg("Failed realloc of size %zu", buff_size);
goto end;
}
buffer = newbuffer;
}
if(remaining_length) {
/* reading variable header and payload into buffer */
rc = sread(fd, buffer, remaining_length);
if(rc > 0) {
logmsg("READ %zd bytes", rc);
loghex(buffer, rc);
}
}
if(byte == MQTT_MSG_CONNECT) {
logprotocol(FROM_CLIENT, "CONNECT", remaining_length, dump, buffer, rc);
if(memcmp(protocol, buffer, sizeof(protocol))) {
logmsg("Protocol preamble mismatch");
goto end;
}
/* ignore the connect flag byte and two keepalive bytes */
payload_len = (size_t)(buffer[10] << 8) | buffer[11];
/* first part of the payload is the client ID */
client_id_length = payload_len;
/* checking if user and password flags were set */
conn_flags = buffer[7];
start_usr = client_id_offset + payload_len;
if(usr_flag == (conn_flags & usr_flag)) {
logmsg("User flag is present in CONN flag");
payload_len += (size_t)(buffer[start_usr] << 8) |
buffer[start_usr + 1];
payload_len += 2; /* MSB and LSB for user length */
}
start_passwd = client_id_offset + payload_len;
if(passwd_flag == (conn_flags & passwd_flag)) {
logmsg("Password flag is present in CONN flags");
payload_len += (size_t)(buffer[start_passwd] << 8) |
buffer[start_passwd + 1];
payload_len += 2; /* MSB and LSB for password length */
}
/* check the length of the payload */
if((ssize_t)payload_len != (rc - 12)) {
logmsg("Payload length mismatch, expected %zx got %zx",
rc - 12, payload_len);
goto end;
}
/* check the length of the client ID */
else if((client_id_length + 1) > MAX_CLIENT_ID_LENGTH) {
logmsg("Too large client id");
goto end;
}
memcpy(client_id, &buffer[12], client_id_length);
client_id[client_id_length] = 0;
logmsg("MQTT client connect accepted: %s", client_id);
/* The first packet sent from the Server to the Client MUST be a
CONNACK Packet */
if(connack(dump, fd)) {
logmsg("failed sending CONNACK");
goto end;
}
}
else if(byte == MQTT_MSG_SUBSCRIBE) {
int error;
char *data;
size_t datalen;
logprotocol(FROM_CLIENT, "SUBSCRIBE", remaining_length,
dump, buffer, rc);
logmsg("Incoming SUBSCRIBE");
if(rc < 6) {
logmsg("Too small SUBSCRIBE");
goto end;
}
/* two bytes packet id */
packet_id = (unsigned short)((buffer[0] << 8) | buffer[1]);
/* two bytes topic length */
topic_len = (size_t)(buffer[2] << 8) | buffer[3];
if(topic_len != (remaining_length - 5)) {
logmsg("Wrong topic length, got %zu expected %zu",
topic_len, remaining_length - 5);
goto end;
}
memcpy(topic, &buffer[4], topic_len);
topic[topic_len] = 0;
/* there is a QoS byte (two bits) after the topic */
logmsg("SUBSCRIBE to '%s' [%d]", topic, packet_id);
stream = test2fopen(testno, logdir);
if(!stream) {
char errbuf[STRERROR_LEN];
error = errno;
logmsg("fopen() failed with error (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
logmsg("Could not open test file %ld", testno);
goto end;
}
error = getpart(&data, &datalen, "reply", "data", stream);
if(!error) {
if(!m_config.publish_before_suback) {
if(suback(dump, fd, packet_id)) {
logmsg("failed sending SUBACK");
free(data);
goto end;
}
}
if(publish(dump, fd, packet_id, topic, data, datalen)) {
logmsg("PUBLISH failed");
free(data);
goto end;
}
free(data);
if(m_config.publish_before_suback) {
if(suback(dump, fd, packet_id)) {
logmsg("failed sending SUBACK");
goto end;
}
}
}
else {
const char *def = "this is random payload yes yes it is";
publish(dump, fd, packet_id, topic, def, strlen(def));
}
disconnect(dump, fd);
}
else if((byte & 0xf0) == (MQTT_MSG_PUBLISH & 0xf0)) {
size_t topiclen;
logmsg("Incoming PUBLISH");
logprotocol(FROM_CLIENT, "PUBLISH", remaining_length, dump, buffer, rc);
topiclen = (size_t)(buffer[1 + bytes] << 8) | buffer[2 + bytes];
logmsg("Got %zu bytes topic", topiclen);
#ifdef QOS
/* Handle packetid if there is one. Send puback if QoS > 0 */
puback(dump, fd, 0);
#endif
/* expect a disconnect here */
/* get the request */
rc = sread(fd, &buffer[0], 2);
logmsg("READ %zd bytes [DISCONNECT]", rc);
loghex(buffer, rc);
logprotocol(FROM_CLIENT, "DISCONNECT", 0, dump, buffer, rc);
goto end;
}
else {
/* not supported (yet) */
goto end;
}
} while(1);
end:
if(buffer)
free(buffer);
if(dump)
curlx_fclose(dump);
if(stream)
curlx_fclose(stream);
return CURL_SOCKET_BAD;
}
/*
sockfdp is a pointer to an established stream or CURL_SOCKET_BAD
if sockfd is CURL_SOCKET_BAD, listendfd is a listening socket we must
accept()
*/
static bool mqttd_incoming(curl_socket_t listenfd)
{
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
int clients = 0; /* connected clients */
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
return FALSE;
}
#ifdef HAVE_GETPPID
/* As a last resort, quit if socks5 process becomes orphan. */
if(getppid() <= 1) {
logmsg("process becomes orphan, exiting");
return FALSE;
}
#endif
do {
ssize_t rc;
int error = 0;
char errbuf[STRERROR_LEN];
curl_socket_t sockfd = listenfd;
int maxfd = (int)sockfd;
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_ZERO(&fds_err);
/* there is always a socket to wait for */
FD_SET(sockfd, &fds_read);
do {
/* select() blocking behavior call on blocking descriptors please */
rc = select(maxfd + 1, &fds_read, &fds_write, &fds_err, NULL);
if(got_exit_signal) {
logmsg("signalled to die, exiting...");
return FALSE;
}
} while((rc == -1) && ((error = SOCKERRNO) == SOCKEINTR));
if(rc < 0) {
logmsg("select() failed with error (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
return FALSE;
}
if(FD_ISSET(sockfd, &fds_read)) {
curl_socket_t newfd = accept(sockfd, NULL, NULL);
if(newfd == CURL_SOCKET_BAD) {
error = SOCKERRNO;
logmsg("accept() failed with error (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
}
else {
logmsg("====> Client connect, fd %ld. "
"Read config from %s", (long)newfd, configfile);
set_advisor_read_lock(loglockfile);
(void)mqttit(newfd); /* until done */
clear_advisor_read_lock(loglockfile);
logmsg("====> Client disconnect");
sclose(newfd);
}
}
} while(clients);
return TRUE;
}
static int test_mqttd(int argc, const char *argv[])
{
curl_socket_t sock = CURL_SOCKET_BAD;
curl_socket_t msgsock = CURL_SOCKET_BAD;
int wrotepidfile = 0;
int wroteportfile = 0;
bool juggle_again;
int error;
char errbuf[STRERROR_LEN];
int arg = 1;
pidname = ".mqttd.pid";
portname = ".mqttd.port";
serverlogfile = "log/mqttd.log";
configfile = "mqttd.config";
server_port = 1883; /* MQTT default port */
while(argc > arg) {
const char *opt;
curl_off_t num;
if(!strcmp("--version", argv[arg])) {
printf("mqttd IPv4%s\n",
#ifdef USE_IPV6
"/IPv6"
#else
""
#endif
);
return 0;
}
else if(!strcmp("--pidfile", argv[arg])) {
arg++;
if(argc > arg)
pidname = argv[arg++];
}
else if(!strcmp("--portfile", argv[arg])) {
arg++;
if(argc > arg)
portname = argv[arg++];
}
else if(!strcmp("--config", argv[arg])) {
arg++;
if(argc > arg)
configfile = argv[arg++];
}
else if(!strcmp("--logfile", argv[arg])) {
arg++;
if(argc > arg)
serverlogfile = argv[arg++];
}
else if(!strcmp("--logdir", argv[arg])) {
arg++;
if(argc > arg)
logdir = argv[arg++];
}
else if(!strcmp("--ipv6", argv[arg])) {
#ifdef USE_IPV6
socket_domain = AF_INET6;
ipv_inuse = "IPv6";
#endif
arg++;
}
else if(!strcmp("--ipv4", argv[arg])) {
/* for completeness, we support this option as well */
#ifdef USE_IPV6
socket_domain = AF_INET;
ipv_inuse = "IPv4";
#endif
arg++;
}
else if(!strcmp("--port", argv[arg])) {
arg++;
if(argc > arg) {
opt = argv[arg];
if(curlx_str_number(&opt, &num, 0xffff)) {
fprintf(stderr, "mqttd: invalid --port argument (%s)\n", argv[arg]);
return 0;
}
server_port = (unsigned short)num;
arg++;
}
}
else {
puts("Usage: mqttd [option]\n"
" --config [file]\n"
" --version\n"
" --logfile [file]\n"
" --logdir [directory]\n"
" --pidfile [file]\n"
" --portfile [file]\n"
" --ipv4\n"
" --ipv6\n"
" --port [port]\n");
return 0;
}
}
snprintf(loglockfile, sizeof(loglockfile), "%s/%s/mqtt-%s.lock",
logdir, SERVERLOGS_LOCKDIR, ipv_inuse);
CURL_BINMODE(stdin);
CURL_BINMODE(stdout);
CURL_BINMODE(stderr);
install_signal_handlers(FALSE);
sock = socket(socket_domain, SOCK_STREAM, 0);
if(sock == CURL_SOCKET_BAD) {
error = SOCKERRNO;
logmsg("Error creating socket (%d) %s",
error, curlx_strerror(error, errbuf, sizeof(errbuf)));
goto mqttd_cleanup;
}
{
/* passive daemon style */
sock = sockdaemon(sock, &server_port, NULL, FALSE);
if(sock == CURL_SOCKET_BAD) {
goto mqttd_cleanup;
}
msgsock = CURL_SOCKET_BAD; /* no stream socket yet */
}
logmsg("Running %s version", ipv_inuse);
logmsg("Listening on port %hu", server_port);
wrotepidfile = write_pidfile(pidname);
if(!wrotepidfile) {
goto mqttd_cleanup;
}
wroteportfile = write_portfile(portname, server_port);
if(!wroteportfile) {
goto mqttd_cleanup;
}
do {
juggle_again = mqttd_incoming(sock);
} while(juggle_again);
mqttd_cleanup:
if((msgsock != sock) && (msgsock != CURL_SOCKET_BAD))
sclose(msgsock);
if(sock != CURL_SOCKET_BAD)
sclose(sock);
if(wrotepidfile)
unlink(pidname);
if(wroteportfile)
unlink(portname);
restore_signal_handlers(FALSE);
if(got_exit_signal) {
logmsg("============> mqttd exits with signal (%d)", exit_signal);
/*
* To properly set the return status of the process we
* must raise the same signal SIGINT or SIGTERM that we
* caught and let the old handler take care of it.
*/
raise(exit_signal);
}
logmsg("============> mqttd quits");
return 0;
}