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curl/lib/mqtt.c
Daniel Stenberg fbf5d507ce
lib/src: white space edits to comply better with code style 
... as checksrc now finds and complains about these.

Closes #14921
2024-09-19 14:59:12 +02:00

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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
* Copyright (C) Björn Stenberg, <bjorn@haxx.se>
*
* 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 "curl_setup.h"
#ifndef CURL_DISABLE_MQTT
#include "urldata.h"
#include <curl/curl.h>
#include "transfer.h"
#include "sendf.h"
#include "progress.h"
#include "mqtt.h"
#include "select.h"
#include "strdup.h"
#include "url.h"
#include "escape.h"
#include "warnless.h"
#include "curl_printf.h"
#include "curl_memory.h"
#include "multiif.h"
#include "rand.h"
/* The last #include file should be: */
#include "memdebug.h"
#define MQTT_MSG_CONNECT 0x10
#define MQTT_MSG_CONNACK 0x20
#define MQTT_MSG_PUBLISH 0x30
#define MQTT_MSG_SUBSCRIBE 0x82
#define MQTT_MSG_SUBACK 0x90
#define MQTT_MSG_DISCONNECT 0xe0
#define MQTT_CONNACK_LEN 2
#define MQTT_SUBACK_LEN 3
#define MQTT_CLIENTID_LEN 12 /* "curl0123abcd" */
/*
* Forward declarations.
*/
static CURLcode mqtt_do(struct Curl_easy *data, bool *done);
static CURLcode mqtt_done(struct Curl_easy *data,
CURLcode status, bool premature);
static CURLcode mqtt_doing(struct Curl_easy *data, bool *done);
static int mqtt_getsock(struct Curl_easy *data, struct connectdata *conn,
curl_socket_t *sock);
static CURLcode mqtt_setup_conn(struct Curl_easy *data,
struct connectdata *conn);
/*
* MQTT protocol handler.
*/
const struct Curl_handler Curl_handler_mqtt = {
"mqtt", /* scheme */
mqtt_setup_conn, /* setup_connection */
mqtt_do, /* do_it */
mqtt_done, /* done */
ZERO_NULL, /* do_more */
ZERO_NULL, /* connect_it */
ZERO_NULL, /* connecting */
mqtt_doing, /* doing */
ZERO_NULL, /* proto_getsock */
mqtt_getsock, /* doing_getsock */
ZERO_NULL, /* domore_getsock */
ZERO_NULL, /* perform_getsock */
ZERO_NULL, /* disconnect */
ZERO_NULL, /* write_resp */
ZERO_NULL, /* write_resp_hd */
ZERO_NULL, /* connection_check */
ZERO_NULL, /* attach connection */
PORT_MQTT, /* defport */
CURLPROTO_MQTT, /* protocol */
CURLPROTO_MQTT, /* family */
PROTOPT_NONE /* flags */
};
static CURLcode mqtt_setup_conn(struct Curl_easy *data,
struct connectdata *conn)
{
/* allocate the HTTP-specific struct for the Curl_easy, only to survive
during this request */
struct MQTT *mq;
(void)conn;
DEBUGASSERT(data->req.p.mqtt == NULL);
mq = calloc(1, sizeof(struct MQTT));
if(!mq)
return CURLE_OUT_OF_MEMORY;
Curl_dyn_init(&mq->recvbuf, DYN_MQTT_RECV);
data->req.p.mqtt = mq;
return CURLE_OK;
}
static CURLcode mqtt_send(struct Curl_easy *data,
char *buf, size_t len)
{
CURLcode result = CURLE_OK;
struct MQTT *mq = data->req.p.mqtt;
size_t n;
result = Curl_xfer_send(data, buf, len, FALSE, &n);
if(result)
return result;
Curl_debug(data, CURLINFO_HEADER_OUT, buf, (size_t)n);
if(len != n) {
size_t nsend = len - n;
char *sendleftovers = Curl_memdup(&buf[n], nsend);
if(!sendleftovers)
return CURLE_OUT_OF_MEMORY;
mq->sendleftovers = sendleftovers;
mq->nsend = nsend;
}
else {
mq->sendleftovers = NULL;
mq->nsend = 0;
}
return result;
}
/* Generic function called by the multi interface to figure out what socket(s)
to wait for and for what actions during the DOING and PROTOCONNECT
states */
static int mqtt_getsock(struct Curl_easy *data,
struct connectdata *conn,
curl_socket_t *sock)
{
(void)data;
sock[0] = conn->sock[FIRSTSOCKET];
return GETSOCK_READSOCK(FIRSTSOCKET);
}
static int mqtt_encode_len(char *buf, size_t len)
{
int i;
for(i = 0; (len > 0) && (i < 4); i++) {
unsigned char encoded;
encoded = len % 0x80;
len /= 0x80;
if(len)
encoded |= 0x80;
buf[i] = (char)encoded;
}
return i;
}
/* add the passwd to the CONNECT packet */
static int add_passwd(const char *passwd, const size_t plen,
char *pkt, const size_t start, int remain_pos)
{
/* magic number that need to be set properly */
const size_t conn_flags_pos = remain_pos + 8;
if(plen > 0xffff)
return 1;
/* set password flag */
pkt[conn_flags_pos] |= 0x40;
/* length of password provided */
pkt[start] = (char)((plen >> 8) & 0xFF);
pkt[start + 1] = (char)(plen & 0xFF);
memcpy(&pkt[start + 2], passwd, plen);
return 0;
}
/* add user to the CONNECT packet */
static int add_user(const char *username, const size_t ulen,
unsigned char *pkt, const size_t start, int remain_pos)
{
/* magic number that need to be set properly */
const size_t conn_flags_pos = remain_pos + 8;
if(ulen > 0xffff)
return 1;
/* set username flag */
pkt[conn_flags_pos] |= 0x80;
/* length of username provided */
pkt[start] = (unsigned char)((ulen >> 8) & 0xFF);
pkt[start + 1] = (unsigned char)(ulen & 0xFF);
memcpy(&pkt[start + 2], username, ulen);
return 0;
}
/* add client ID to the CONNECT packet */
static int add_client_id(const char *client_id, const size_t client_id_len,
char *pkt, const size_t start)
{
if(client_id_len != MQTT_CLIENTID_LEN)
return 1;
pkt[start] = 0x00;
pkt[start + 1] = MQTT_CLIENTID_LEN;
memcpy(&pkt[start + 2], client_id, MQTT_CLIENTID_LEN);
return 0;
}
/* Set initial values of CONNECT packet */
static int init_connpack(char *packet, char *remain, int remain_pos)
{
/* Fixed header starts */
/* packet type */
packet[0] = MQTT_MSG_CONNECT;
/* remaining length field */
memcpy(&packet[1], remain, remain_pos);
/* Fixed header ends */
/* Variable header starts */
/* protocol length */
packet[remain_pos + 1] = 0x00;
packet[remain_pos + 2] = 0x04;
/* protocol name */
packet[remain_pos + 3] = 'M';
packet[remain_pos + 4] = 'Q';
packet[remain_pos + 5] = 'T';
packet[remain_pos + 6] = 'T';
/* protocol level */
packet[remain_pos + 7] = 0x04;
/* CONNECT flag: CleanSession */
packet[remain_pos + 8] = 0x02;
/* keep-alive 0 = disabled */
packet[remain_pos + 9] = 0x00;
packet[remain_pos + 10] = 0x3c;
/* end of variable header */
return remain_pos + 10;
}
static CURLcode mqtt_connect(struct Curl_easy *data)
{
CURLcode result = CURLE_OK;
int pos = 0;
int rc = 0;
/* remain length */
int remain_pos = 0;
char remain[4] = {0};
size_t packetlen = 0;
size_t payloadlen = 0;
size_t start_user = 0;
size_t start_pwd = 0;
char client_id[MQTT_CLIENTID_LEN + 1] = "curl";
const size_t clen = strlen("curl");
char *packet = NULL;
/* extracting username from request */
const char *username = data->state.aptr.user ?
data->state.aptr.user : "";
const size_t ulen = strlen(username);
/* extracting password from request */
const char *passwd = data->state.aptr.passwd ?
data->state.aptr.passwd : "";
const size_t plen = strlen(passwd);
payloadlen = ulen + plen + MQTT_CLIENTID_LEN + 2;
/* The plus 2 are for the MSB and LSB describing the length of the string to
* be added on the payload. Refer to spec 1.5.2 and 1.5.4 */
if(ulen)
payloadlen += 2;
if(plen)
payloadlen += 2;
/* getting how much occupy the remain length */
remain_pos = mqtt_encode_len(remain, payloadlen + 10);
/* 10 length of variable header and 1 the first byte of the fixed header */
packetlen = payloadlen + 10 + remain_pos + 1;
/* allocating packet */
if(packetlen > 268435455)
return CURLE_WEIRD_SERVER_REPLY;
packet = malloc(packetlen);
if(!packet)
return CURLE_OUT_OF_MEMORY;
memset(packet, 0, packetlen);
/* set initial values for the CONNECT packet */
pos = init_connpack(packet, remain, remain_pos);
result = Curl_rand_alnum(data, (unsigned char *)&client_id[clen],
MQTT_CLIENTID_LEN - clen + 1);
/* add client id */
rc = add_client_id(client_id, strlen(client_id), packet, pos + 1);
if(rc) {
failf(data, "Client ID length mismatched: [%zu]", strlen(client_id));
result = CURLE_WEIRD_SERVER_REPLY;
goto end;
}
infof(data, "Using client id '%s'", client_id);
/* position where starts the user payload */
start_user = pos + 3 + MQTT_CLIENTID_LEN;
/* position where starts the password payload */
start_pwd = start_user + ulen;
/* if username was provided, add it to the packet */
if(ulen) {
start_pwd += 2;
rc = add_user(username, ulen,
(unsigned char *)packet, start_user, remain_pos);
if(rc) {
failf(data, "Username is too large: [%zu]", ulen);
result = CURLE_WEIRD_SERVER_REPLY;
goto end;
}
}
/* if passwd was provided, add it to the packet */
if(plen) {
rc = add_passwd(passwd, plen, packet, start_pwd, remain_pos);
if(rc) {
failf(data, "Password is too large: [%zu]", plen);
result = CURLE_WEIRD_SERVER_REPLY;
goto end;
}
}
if(!result)
result = mqtt_send(data, packet, packetlen);
end:
if(packet)
free(packet);
Curl_safefree(data->state.aptr.user);
Curl_safefree(data->state.aptr.passwd);
return result;
}
static CURLcode mqtt_disconnect(struct Curl_easy *data)
{
CURLcode result = CURLE_OK;
struct MQTT *mq = data->req.p.mqtt;
result = mqtt_send(data, (char *)"\xe0\x00", 2);
Curl_safefree(mq->sendleftovers);
Curl_dyn_free(&mq->recvbuf);
return result;
}
static CURLcode mqtt_recv_atleast(struct Curl_easy *data, size_t nbytes)
{
struct MQTT *mq = data->req.p.mqtt;
size_t rlen = Curl_dyn_len(&mq->recvbuf);
CURLcode result;
if(rlen < nbytes) {
unsigned char readbuf[1024];
ssize_t nread;
DEBUGASSERT(nbytes - rlen < sizeof(readbuf));
result = Curl_xfer_recv(data, (char *)readbuf, nbytes - rlen, &nread);
if(result)
return result;
DEBUGASSERT(nread >= 0);
if(Curl_dyn_addn(&mq->recvbuf, readbuf, (size_t)nread))
return CURLE_OUT_OF_MEMORY;
rlen = Curl_dyn_len(&mq->recvbuf);
}
return (rlen >= nbytes) ? CURLE_OK : CURLE_AGAIN;
}
static void mqtt_recv_consume(struct Curl_easy *data, size_t nbytes)
{
struct MQTT *mq = data->req.p.mqtt;
size_t rlen = Curl_dyn_len(&mq->recvbuf);
if(rlen <= nbytes)
Curl_dyn_reset(&mq->recvbuf);
else
Curl_dyn_tail(&mq->recvbuf, rlen - nbytes);
}
static CURLcode mqtt_verify_connack(struct Curl_easy *data)
{
struct MQTT *mq = data->req.p.mqtt;
CURLcode result;
char *ptr;
result = mqtt_recv_atleast(data, MQTT_CONNACK_LEN);
if(result)
goto fail;
/* verify CONNACK */
DEBUGASSERT(Curl_dyn_len(&mq->recvbuf) >= MQTT_CONNACK_LEN);
ptr = Curl_dyn_ptr(&mq->recvbuf);
Curl_debug(data, CURLINFO_HEADER_IN, ptr, MQTT_CONNACK_LEN);
if(ptr[0] != 0x00 || ptr[1] != 0x00) {
failf(data, "Expected %02x%02x but got %02x%02x",
0x00, 0x00, ptr[0], ptr[1]);
Curl_dyn_reset(&mq->recvbuf);
result = CURLE_WEIRD_SERVER_REPLY;
goto fail;
}
mqtt_recv_consume(data, MQTT_CONNACK_LEN);
fail:
return result;
}
static CURLcode mqtt_get_topic(struct Curl_easy *data,
char **topic, size_t *topiclen)
{
char *path = data->state.up.path;
CURLcode result = CURLE_URL_MALFORMAT;
if(strlen(path) > 1) {
result = Curl_urldecode(path + 1, 0, topic, topiclen, REJECT_NADA);
if(!result && (*topiclen > 0xffff)) {
failf(data, "Too long MQTT topic");
result = CURLE_URL_MALFORMAT;
}
}
else
failf(data, "No MQTT topic found. Forgot to URL encode it?");
return result;
}
static CURLcode mqtt_subscribe(struct Curl_easy *data)
{
CURLcode result = CURLE_OK;
char *topic = NULL;
size_t topiclen;
unsigned char *packet = NULL;
size_t packetlen;
char encodedsize[4];
size_t n;
struct connectdata *conn = data->conn;
result = mqtt_get_topic(data, &topic, &topiclen);
if(result)
goto fail;
conn->proto.mqtt.packetid++;
packetlen = topiclen + 5; /* packetid + topic (has a two byte length field)
+ 2 bytes topic length + QoS byte */
n = mqtt_encode_len((char *)encodedsize, packetlen);
packetlen += n + 1; /* add one for the control packet type byte */
packet = malloc(packetlen);
if(!packet) {
result = CURLE_OUT_OF_MEMORY;
goto fail;
}
packet[0] = MQTT_MSG_SUBSCRIBE;
memcpy(&packet[1], encodedsize, n);
packet[1 + n] = (conn->proto.mqtt.packetid >> 8) & 0xff;
packet[2 + n] = conn->proto.mqtt.packetid & 0xff;
packet[3 + n] = (topiclen >> 8) & 0xff;
packet[4 + n ] = topiclen & 0xff;
memcpy(&packet[5 + n], topic, topiclen);
packet[5 + n + topiclen] = 0; /* QoS zero */
result = mqtt_send(data, (char *)packet, packetlen);
fail:
free(topic);
free(packet);
return result;
}
/*
* Called when the first byte was already read.
*/
static CURLcode mqtt_verify_suback(struct Curl_easy *data)
{
struct MQTT *mq = data->req.p.mqtt;
struct connectdata *conn = data->conn;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
CURLcode result;
char *ptr;
result = mqtt_recv_atleast(data, MQTT_SUBACK_LEN);
if(result)
goto fail;
/* verify SUBACK */
DEBUGASSERT(Curl_dyn_len(&mq->recvbuf) >= MQTT_SUBACK_LEN);
ptr = Curl_dyn_ptr(&mq->recvbuf);
Curl_debug(data, CURLINFO_HEADER_IN, ptr, MQTT_SUBACK_LEN);
if(((unsigned char)ptr[0]) != ((mqtt->packetid >> 8) & 0xff) ||
((unsigned char)ptr[1]) != (mqtt->packetid & 0xff) ||
ptr[2] != 0x00) {
Curl_dyn_reset(&mq->recvbuf);
result = CURLE_WEIRD_SERVER_REPLY;
goto fail;
}
mqtt_recv_consume(data, MQTT_SUBACK_LEN);
fail:
return result;
}
static CURLcode mqtt_publish(struct Curl_easy *data)
{
CURLcode result;
char *payload = data->set.postfields;
size_t payloadlen;
char *topic = NULL;
size_t topiclen;
unsigned char *pkt = NULL;
size_t i = 0;
size_t remaininglength;
size_t encodelen;
char encodedbytes[4];
curl_off_t postfieldsize = data->set.postfieldsize;
if(!payload) {
DEBUGF(infof(data, "mqtt_publish without payload, return bad arg"));
return CURLE_BAD_FUNCTION_ARGUMENT;
}
if(postfieldsize < 0)
payloadlen = strlen(payload);
else
payloadlen = (size_t)postfieldsize;
result = mqtt_get_topic(data, &topic, &topiclen);
if(result)
goto fail;
remaininglength = payloadlen + 2 + topiclen;
encodelen = mqtt_encode_len(encodedbytes, remaininglength);
/* add the control byte and the encoded remaining length */
pkt = malloc(remaininglength + 1 + encodelen);
if(!pkt) {
result = CURLE_OUT_OF_MEMORY;
goto fail;
}
/* assemble packet */
pkt[i++] = MQTT_MSG_PUBLISH;
memcpy(&pkt[i], encodedbytes, encodelen);
i += encodelen;
pkt[i++] = (topiclen >> 8) & 0xff;
pkt[i++] = (topiclen & 0xff);
memcpy(&pkt[i], topic, topiclen);
i += topiclen;
memcpy(&pkt[i], payload, payloadlen);
i += payloadlen;
result = mqtt_send(data, (char *)pkt, i);
fail:
free(pkt);
free(topic);
return result;
}
static size_t mqtt_decode_len(unsigned char *buf,
size_t buflen, size_t *lenbytes)
{
size_t len = 0;
size_t mult = 1;
size_t i;
unsigned char encoded = 128;
for(i = 0; (i < buflen) && (encoded & 128); i++) {
encoded = buf[i];
len += (encoded & 127) * mult;
mult *= 128;
}
if(lenbytes)
*lenbytes = i;
return len;
}
#ifdef DEBUGBUILD
static const char *statenames[]={
"MQTT_FIRST",
"MQTT_REMAINING_LENGTH",
"MQTT_CONNACK",
"MQTT_SUBACK",
"MQTT_SUBACK_COMING",
"MQTT_PUBWAIT",
"MQTT_PUB_REMAIN",
"NOT A STATE"
};
#endif
/* The only way to change state */
static void mqstate(struct Curl_easy *data,
enum mqttstate state,
enum mqttstate nextstate) /* used if state == FIRST */
{
struct connectdata *conn = data->conn;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
#ifdef DEBUGBUILD
infof(data, "%s (from %s) (next is %s)",
statenames[state],
statenames[mqtt->state],
(state == MQTT_FIRST) ? statenames[nextstate] : "");
#endif
mqtt->state = state;
if(state == MQTT_FIRST)
mqtt->nextstate = nextstate;
}
static CURLcode mqtt_read_publish(struct Curl_easy *data, bool *done)
{
CURLcode result = CURLE_OK;
struct connectdata *conn = data->conn;
ssize_t nread;
size_t remlen;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
struct MQTT *mq = data->req.p.mqtt;
unsigned char packet;
switch(mqtt->state) {
MQTT_SUBACK_COMING:
case MQTT_SUBACK_COMING:
result = mqtt_verify_suback(data);
if(result)
break;
mqstate(data, MQTT_FIRST, MQTT_PUBWAIT);
break;
case MQTT_SUBACK:
case MQTT_PUBWAIT:
/* we are expecting PUBLISH or SUBACK */
packet = mq->firstbyte & 0xf0;
if(packet == MQTT_MSG_PUBLISH)
mqstate(data, MQTT_PUB_REMAIN, MQTT_NOSTATE);
else if(packet == MQTT_MSG_SUBACK) {
mqstate(data, MQTT_SUBACK_COMING, MQTT_NOSTATE);
goto MQTT_SUBACK_COMING;
}
else if(packet == MQTT_MSG_DISCONNECT) {
infof(data, "Got DISCONNECT");
*done = TRUE;
goto end;
}
else {
result = CURLE_WEIRD_SERVER_REPLY;
goto end;
}
/* -- switched state -- */
remlen = mq->remaining_length;
infof(data, "Remaining length: %zu bytes", remlen);
if(data->set.max_filesize &&
(curl_off_t)remlen > data->set.max_filesize) {
failf(data, "Maximum file size exceeded");
result = CURLE_FILESIZE_EXCEEDED;
goto end;
}
Curl_pgrsSetDownloadSize(data, remlen);
data->req.bytecount = 0;
data->req.size = remlen;
mq->npacket = remlen; /* get this many bytes */
FALLTHROUGH();
case MQTT_PUB_REMAIN: {
/* read rest of packet, but no more. Cap to buffer size */
char buffer[4*1024];
size_t rest = mq->npacket;
if(rest > sizeof(buffer))
rest = sizeof(buffer);
result = Curl_xfer_recv(data, buffer, rest, &nread);
if(result) {
if(CURLE_AGAIN == result) {
infof(data, "EEEE AAAAGAIN");
}
goto end;
}
if(!nread) {
infof(data, "server disconnected");
result = CURLE_PARTIAL_FILE;
goto end;
}
/* if QoS is set, message contains packet id */
result = Curl_client_write(data, CLIENTWRITE_BODY, buffer, nread);
if(result)
goto end;
mq->npacket -= nread;
if(!mq->npacket)
/* no more PUBLISH payload, back to subscribe wait state */
mqstate(data, MQTT_FIRST, MQTT_PUBWAIT);
break;
}
default:
DEBUGASSERT(NULL); /* illegal state */
result = CURLE_WEIRD_SERVER_REPLY;
goto end;
}
end:
return result;
}
static CURLcode mqtt_do(struct Curl_easy *data, bool *done)
{
CURLcode result = CURLE_OK;
*done = FALSE; /* unconditionally */
result = mqtt_connect(data);
if(result) {
failf(data, "Error %d sending MQTT CONNECT request", result);
return result;
}
mqstate(data, MQTT_FIRST, MQTT_CONNACK);
return CURLE_OK;
}
static CURLcode mqtt_done(struct Curl_easy *data,
CURLcode status, bool premature)
{
struct MQTT *mq = data->req.p.mqtt;
(void)status;
(void)premature;
Curl_safefree(mq->sendleftovers);
Curl_dyn_free(&mq->recvbuf);
return CURLE_OK;
}
static CURLcode mqtt_doing(struct Curl_easy *data, bool *done)
{
CURLcode result = CURLE_OK;
struct connectdata *conn = data->conn;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
struct MQTT *mq = data->req.p.mqtt;
ssize_t nread;
unsigned char recvbyte;
*done = FALSE;
if(mq->nsend) {
/* send the remainder of an outgoing packet */
char *ptr = mq->sendleftovers;
result = mqtt_send(data, mq->sendleftovers, mq->nsend);
free(ptr);
if(result)
return result;
}
infof(data, "mqtt_doing: state [%d]", (int) mqtt->state);
switch(mqtt->state) {
case MQTT_FIRST:
/* Read the initial byte only */
result = Curl_xfer_recv(data, (char *)&mq->firstbyte, 1, &nread);
if(result)
break;
else if(!nread) {
failf(data, "Connection disconnected");
*done = TRUE;
result = CURLE_RECV_ERROR;
break;
}
Curl_debug(data, CURLINFO_HEADER_IN, (char *)&mq->firstbyte, 1);
/* remember the first byte */
mq->npacket = 0;
mqstate(data, MQTT_REMAINING_LENGTH, MQTT_NOSTATE);
FALLTHROUGH();
case MQTT_REMAINING_LENGTH:
do {
result = Curl_xfer_recv(data, (char *)&recvbyte, 1, &nread);
if(result || !nread)
break;
Curl_debug(data, CURLINFO_HEADER_IN, (char *)&recvbyte, 1);
mq->pkt_hd[mq->npacket++] = recvbyte;
} while((recvbyte & 0x80) && (mq->npacket < 4));
if(!result && nread && (recvbyte & 0x80))
/* MQTT supports up to 127 * 128^0 + 127 * 128^1 + 127 * 128^2 +
127 * 128^3 bytes. server tried to send more */
result = CURLE_WEIRD_SERVER_REPLY;
if(result)
break;
mq->remaining_length = mqtt_decode_len(mq->pkt_hd, mq->npacket, NULL);
mq->npacket = 0;
if(mq->remaining_length) {
mqstate(data, mqtt->nextstate, MQTT_NOSTATE);
break;
}
mqstate(data, MQTT_FIRST, MQTT_FIRST);
if(mq->firstbyte == MQTT_MSG_DISCONNECT) {
infof(data, "Got DISCONNECT");
*done = TRUE;
}
break;
case MQTT_CONNACK:
result = mqtt_verify_connack(data);
if(result)
break;
if(data->state.httpreq == HTTPREQ_POST) {
result = mqtt_publish(data);
if(!result) {
result = mqtt_disconnect(data);
*done = TRUE;
}
mqtt->nextstate = MQTT_FIRST;
}
else {
result = mqtt_subscribe(data);
if(!result) {
mqstate(data, MQTT_FIRST, MQTT_SUBACK);
}
}
break;
case MQTT_SUBACK:
case MQTT_PUBWAIT:
case MQTT_PUB_REMAIN:
result = mqtt_read_publish(data, done);
break;
default:
failf(data, "State not handled yet");
*done = TRUE;
break;
}
if(result == CURLE_AGAIN)
result = CURLE_OK;
return result;
}
#endif /* CURL_DISABLE_MQTT */
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