moparisthebest/curl
1
0
Fork 0
mirror of https://github.com/moparisthebest/curl synced 2024-11-18 07:25:14 -05:00
Code Issues Releases Wiki Activity
41f5b66a02
curl/lib/mqtt.c
Bjorn Stenberg 2522903b79
mqtt: add new experimental protocol 
Closes #5173
2020-04-14 13:03:40 +02:00

562 lines
15 KiB
C
Raw Blame History

/***************************************************************************
* _ _ ____ _
* 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 4
#define MQTT_SUBACK_LEN 5
#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] != MQTT_MSG_CONNACK ||
readbuf[1] != 0x02 ||
readbuf[2] != 0x00 ||
readbuf[3] != 0x00) {
failf(data, "Expected %02x%02x%02x%02x but got %02x%02x%02x%02x",
MQTT_MSG_CONNACK, 0x02, 0x00, 0x00,
readbuf[0], readbuf[1], readbuf[2], readbuf[3]);
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;
}
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_MSG_SUBACK ||
readbuf[1] != 0x03 ||
readbuf[2] != ((mqtt->packetid >> 8) & 0xff) ||
readbuf[3] != (mqtt->packetid & 0xff) ||
readbuf[4] != 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;
}
*lenbytes = i;
return len;
}
/* for the publish packet */
#define MQTT_HEADER_LEN 5 /* max 5 bytes */
static CURLcode mqtt_read_publish(struct connectdata *conn,
bool *done)
{
CURLcode result;
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, lenbytes;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
struct MQTT *mq = data->req.protop;
switch(mqtt->state) {
case MQTT_SUBWAIT:
/* Read the initial byte and the entire Remaining Length field
in this state */
result = Curl_read(conn, sockfd, (char *)&pkt[mq->npacket], 1, &nread);
if(result)
goto end;
if(data->set.verbose)
Curl_debug(data, CURLINFO_HEADER_IN, (char *)&pkt[mq->npacket], 1);
/* we are expecting a PUBLISH message */
if(!mq->npacket && ((pkt[0] & 0xf0) != MQTT_MSG_PUBLISH)) {
if(pkt[0] == MQTT_MSG_DISCONNECT) {
infof(data, "Got DISCONNECT\n");
*done = TRUE;
goto end;
}
result = CURLE_WEIRD_SERVER_REPLY;
goto end;
}
else if((mq->npacket >= 1) && !(pkt[mq->npacket] & 0x80))
/* as long as the high bit is set in the length byte, we read one more
byte, then get the remainder of the PUBLISH */
mqtt->state = MQTT_SUB_REMAIN;
mq->npacket++;
if(mqtt->state == MQTT_SUBWAIT)
return result;
/* -- switched state -- */
/* remember the first byte */
mq->firstbyte = pkt[0];
remlen = mqtt_decode_len(&pkt[1], 4, &lenbytes);
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_SUB_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(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 */
mqtt->state = MQTT_SUBWAIT;
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;
struct mqtt_conn *mqtt = &conn->proto.mqtt;
*done = FALSE; /* unconditionally */
result = mqtt_connect(conn);
if(result) {
failf(data, "Error %d sending MQTT CONN request", result);
return result;
}
mqtt->state = 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;
*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;
}
switch(mqtt->state) {
case MQTT_CONNACK:
result = mqtt_verify_connack(conn);
if(result)
break;
if(conn->data->set.httpreq == HTTPREQ_POST) {
result = mqtt_publish(conn);
if(!result) {
result = mqtt_disconnect(conn);
*done = TRUE;
}
}
else {
result = mqtt_subscribe(conn);
if(!result)
mqtt->state = MQTT_SUBACK;
}
break;
case MQTT_SUBACK:
result = mqtt_verify_suback(conn);
if(result)
break;
mqtt->state = MQTT_SUBWAIT;
break;
case MQTT_SUBWAIT:
case MQTT_SUB_REMAIN:
result = mqtt_read_publish(conn, done);
if(result)
break;
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 */
Reference in New Issue View Git Blame Copy Permalink