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8b4e796775
curl/lib/mqtt.c
Daniel Stenberg 9c845be279
urldata: let the HTTP method be in the set.* struct 
When the method is updated inside libcurl we must still not change the
method as set by the user as then repeated transfers with that same
handle might not execute the same operation anymore!

This fixes the libcurl part of #5462

Test 1633 added to verify.

Closes #5499
2020-06-02 16:30:36 +02:00

628 lines
17 KiB
C
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
* Copyright (C) 2019, 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.haxx.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.
*
***************************************************************************/
#include "curl_setup.h"
#ifdef CURL_ENABLE_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 connectdata *conn, bool *done);
static CURLcode mqtt_doing(struct connectdata *conn, bool *done);
static int mqtt_getsock(struct connectdata *conn, curl_socket_t *sock);
static CURLcode mqtt_setup_conn(struct connectdata *conn);
/*
* MQTT protocol handler.
*/
const struct Curl_handler Curl_handler_mqtt = {
"MQTT", /* scheme */
mqtt_setup_conn, /* setup_connection */
mqtt_do, /* do_it */
ZERO_NULL, /* 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, /* readwrite */
ZERO_NULL, /* connection_check */
PORT_MQTT, /* defport */
CURLPROTO_MQTT, /* protocol */
PROTOPT_NONE /* flags */
};
static CURLcode mqtt_setup_conn(struct connectdata *conn)
{
/* allocate the HTTP-specific struct for the Curl_easy, only to survive
during this request */
struct MQTT *mq;
struct Curl_easy *data = conn->data;
DEBUGASSERT(data->req.protop == NULL);
mq = calloc(1, sizeof(struct MQTT));
if(!mq)
return CURLE_OUT_OF_MEMORY;
data->req.protop = mq;
return CURLE_OK;
}
static CURLcode mqtt_send(struct connectdata *conn,
char *buf, size_t len)
{
CURLcode result = CURLE_OK;
curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
struct Curl_easy *data = conn->data;
struct MQTT *mq = data->req.protop;
ssize_t n;
result = Curl_write(conn, sockfd, buf, len, &n);
if(!result && data->set.verbose)
Curl_debug(data, CURLINFO_HEADER_OUT, buf, (size_t)n);
if(len != (size_t)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;
}
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 connectdata *conn,
curl_socket_t *sock)
{
sock[0] = conn->sock[FIRSTSOCKET];
return GETSOCK_READSOCK(FIRSTSOCKET);
}
static CURLcode mqtt_connect(struct connectdata *conn)
{
CURLcode result = CURLE_OK;
const size_t client_id_offset = 14;
const size_t packetlen = client_id_offset + MQTT_CLIENTID_LEN;
char client_id[MQTT_CLIENTID_LEN + 1] = "curl";
const size_t curl_len = strlen("curl");
char packet[32] = {
MQTT_MSG_CONNECT, /* packet type */
0x00, /* remaining length */
0x00, 0x04, /* protocol length */
'M','Q','T','T', /* protocol name */
0x04, /* protocol level */
0x02, /* CONNECT flag: CleanSession */
0x00, 0x3c, /* keep-alive 0 = disabled */
0x00, 0x00 /* payload1 length */
};
packet[1] = (packetlen - 2) & 0x7f;
packet[client_id_offset - 1] = MQTT_CLIENTID_LEN;
result = Curl_rand_hex(conn->data, (unsigned char *)&client_id[curl_len],
MQTT_CLIENTID_LEN - curl_len + 1);
memcpy(&packet[client_id_offset], client_id, MQTT_CLIENTID_LEN);
infof(conn->data, "Using client id '%s'\n", client_id);
if(!result)
result = mqtt_send(conn, packet, packetlen);
return result;
}
static CURLcode mqtt_disconnect(struct connectdata *conn)
{
CURLcode result = CURLE_OK;
result = mqtt_send(conn, (char *)"\xe0\x00", 2);
return result;
}
static CURLcode mqtt_verify_connack(struct connectdata *conn)
{
CURLcode result;
curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
unsigned char readbuf[MQTT_CONNACK_LEN];
ssize_t nread;
struct Curl_easy *data = conn->data;
result = Curl_read(conn, sockfd, (char *)readbuf, MQTT_CONNACK_LEN, &nread);
if(result)
goto fail;
if(data->set.verbose)
Curl_debug(data, CURLINFO_HEADER_IN, (char *)readbuf, (size_t)nread);
/* fixme */
if(nread < MQTT_CONNACK_LEN) {
result = CURLE_WEIRD_SERVER_REPLY;
goto fail;
}
/* verify CONNACK */
if(readbuf[0] != 0x00 || readbuf[1] != 0x00) {
failf(data, "Expected %02x%02x but got %02x%02x",
0x00, 0x00, readbuf[0], readbuf[1]);
result = CURLE_WEIRD_SERVER_REPLY;
}
fail:
return result;
}
static CURLcode mqtt_get_topic(struct connectdata *conn,
char **topic, size_t *topiclen)
{
CURLcode result = CURLE_OK;
char *path = conn->data->state.up.path;
if(strlen(path) > 1) {
result = Curl_urldecode(conn->data, path + 1, 0, topic, topiclen, FALSE);
}
else {
failf(conn->data, "Error: No topic specified.");
result = CURLE_URL_MALFORMAT;
}
return result;
}
static int mqtt_encode_len(char *buf, size_t len)
{
unsigned char encoded;
int i;
for(i = 0; (len > 0) && (i<4); i++) {
encoded = len % 0x80;
len /= 0x80;
if(len)
encoded |= 0x80;
buf[i] = encoded;
}
return i;
}
static CURLcode mqtt_subscribe(struct connectdata *conn)
{
CURLcode result = CURLE_OK;
char *topic = NULL;
size_t topiclen;
unsigned char *packet = NULL;
size_t packetlen;
char encodedsize[4];
size_t n;
result = mqtt_get_topic(conn, &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(conn, (char *)packet, packetlen);
fail:
free(topic);
free(packet);
return result;
}
/*
* Called when the first byte was already read.
*/
static CURLcode mqtt_verify_suback(struct connectdata *conn)
{
CURLcode result;
curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
unsigned char readbuf[MQTT_SUBACK_LEN];
ssize_t nread;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
result = Curl_read(conn, sockfd, (char *)readbuf, MQTT_SUBACK_LEN, &nread);
if(result)
goto fail;
if(conn->data->set.verbose)
Curl_debug(conn->data, CURLINFO_HEADER_IN, (char *)readbuf, (size_t)nread);
/* fixme */
if(nread < MQTT_SUBACK_LEN) {
result = CURLE_WEIRD_SERVER_REPLY;
goto fail;
}
/* verify SUBACK */
if(readbuf[0] != ((mqtt->packetid >> 8) & 0xff) ||
readbuf[1] != (mqtt->packetid & 0xff) ||
readbuf[2] != 0x00)
result = CURLE_WEIRD_SERVER_REPLY;
fail:
return result;
}
static CURLcode mqtt_publish(struct connectdata *conn)
{
CURLcode result;
char *payload = conn->data->set.postfields;
size_t payloadlen = (size_t)conn->data->set.postfieldsize;
char *topic = NULL;
size_t topiclen;
unsigned char *pkt = NULL;
size_t i = 0;
size_t remaininglength;
size_t encodelen;
char encodedbytes[4];
result = mqtt_get_topic(conn, &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(conn, (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 CURLDEBUG
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 connectdata *conn,
enum mqttstate state,
enum mqttstate nextstate) /* used if state == FIRST */
{
struct mqtt_conn *mqtt = &conn->proto.mqtt;
#ifdef CURLDEBUG
infof(conn->data, "%s (from %s) (next is %s)\n",
statenames[state],
statenames[mqtt->state],
(state == MQTT_FIRST)? statenames[nextstate] : "");
#endif
mqtt->state = state;
if(state == MQTT_FIRST)
mqtt->nextstate = nextstate;
}
/* for the publish packet */
#define MQTT_HEADER_LEN 5 /* max 5 bytes */
static CURLcode mqtt_read_publish(struct connectdata *conn,
bool *done)
{
CURLcode result = CURLE_OK;
curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
ssize_t nread;
struct Curl_easy *data = conn->data;
unsigned char *pkt = (unsigned char *)data->state.buffer;
size_t remlen;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
struct MQTT *mq = data->req.protop;
unsigned char packet;
switch(mqtt->state) {
MQTT_SUBACK_COMING:
case MQTT_SUBACK_COMING:
result = mqtt_verify_suback(conn);
if(result)
break;
mqstate(conn, 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(conn, MQTT_PUB_REMAIN, MQTT_NOSTATE);
else if(packet == MQTT_MSG_SUBACK) {
mqstate(conn, MQTT_SUBACK_COMING, MQTT_NOSTATE);
goto MQTT_SUBACK_COMING;
}
else if(packet == MQTT_MSG_DISCONNECT) {
infof(data, "Got DISCONNECT\n");
*done = TRUE;
goto end;
}
else {
result = CURLE_WEIRD_SERVER_REPLY;
goto end;
}
/* -- switched state -- */
remlen = mq->remaining_length;
infof(data, "Remaining length: %zd bytes\n", remlen);
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 */
struct SingleRequest *k = &data->req;
size_t rest = mq->npacket;
if(rest > (size_t)data->set.buffer_size)
rest = (size_t)data->set.buffer_size;
result = Curl_read(conn, sockfd, (char *)pkt, rest, &nread);
if(result) {
if(CURLE_AGAIN == result) {
infof(data, "EEEE AAAAGAIN\n");
}
goto end;
}
if(!nread) {
infof(data, "server disconnected\n");
result = CURLE_PARTIAL_FILE;
goto end;
}
if(data->set.verbose)
Curl_debug(data, CURLINFO_DATA_IN, (char *)pkt, (size_t)nread);
mq->npacket -= nread;
k->bytecount += nread;
Curl_pgrsSetDownloadCounter(data, k->bytecount);
/* if QoS is set, message contains packet id */
result = Curl_client_write(conn, CLIENTWRITE_BODY, (char *)pkt, nread);
if(result)
goto end;
if(!mq->npacket)
/* no more PUBLISH payload, back to subscribe wait state */
mqstate(conn, 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 connectdata *conn, bool *done)
{
CURLcode result = CURLE_OK;
struct Curl_easy *data = conn->data;
*done = FALSE; /* unconditionally */
result = mqtt_connect(conn);
if(result) {
failf(data, "Error %d sending MQTT CONN request", result);
return result;
}
mqstate(conn, MQTT_FIRST, MQTT_CONNACK);
return CURLE_OK;
}
static CURLcode mqtt_doing(struct connectdata *conn, bool *done)
{
CURLcode result = CURLE_OK;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
struct Curl_easy *data = conn->data;
struct MQTT *mq = data->req.protop;
ssize_t nread;
curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
unsigned char *pkt = (unsigned char *)data->state.buffer;
unsigned char byte;
*done = FALSE;
if(mq->nsend) {
/* send the remainder of an outgoing packet */
char *ptr = mq->sendleftovers;
result = mqtt_send(conn, mq->sendleftovers, mq->nsend);
free(ptr);
if(result)
return result;
}
infof(data, "mqtt_doing: state [%d]\n", (int) mqtt->state);
switch(mqtt->state) {
case MQTT_FIRST:
/* Read the initial byte only */
result = Curl_read(conn, sockfd, (char *)&mq->firstbyte, 1, &nread);
if(result)
break;
if(data->set.verbose)
Curl_debug(data, CURLINFO_HEADER_IN, (char *)&mq->firstbyte, 1);
/* remember the first byte */
mq->npacket = 0;
mqstate(conn, MQTT_REMAINING_LENGTH, MQTT_NOSTATE);
/* FALLTHROUGH */
case MQTT_REMAINING_LENGTH:
do {
result = Curl_read(conn, sockfd, (char *)&byte, 1, &nread);
if(result)
break;
if(data->set.verbose)
Curl_debug(data, CURLINFO_HEADER_IN, (char *)&byte, 1);
pkt[mq->npacket++] = byte;
} while((byte & 0x80) && (mq->npacket < 4));
if(result)
break;
mq->remaining_length = mqtt_decode_len(&pkt[0], mq->npacket, NULL);
mq->npacket = 0;
if(mq->remaining_length) {
mqstate(conn, mqtt->nextstate, MQTT_NOSTATE);
break;
}
mqstate(conn, MQTT_FIRST, MQTT_FIRST);
if(mq->firstbyte == MQTT_MSG_DISCONNECT) {
infof(data, "Got DISCONNECT\n");
*done = TRUE;
}
break;
case MQTT_CONNACK:
result = mqtt_verify_connack(conn);
if(result)
break;
if(conn->data->state.httpreq == HTTPREQ_POST) {
result = mqtt_publish(conn);
if(!result) {
result = mqtt_disconnect(conn);
*done = TRUE;
}
mqtt->nextstate = MQTT_FIRST;
}
else {
result = mqtt_subscribe(conn);
if(!result) {
mqstate(conn, MQTT_FIRST, MQTT_SUBACK);
}
}
break;
case MQTT_SUBACK:
case MQTT_PUBWAIT:
case MQTT_PUB_REMAIN:
result = mqtt_read_publish(conn, done);
break;
default:
failf(conn->data, "State not handled yet");
*done = TRUE;
break;
}
if(result == CURLE_AGAIN)
result = CURLE_OK;
return result;
}
#endif /* CURL_ENABLE_MQTT */
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