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8d45cf697216cd10968af937918b2712e243650f
mongoose/src/mqtt.c
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cpq 8d45cf6972 Add mqtt-server example
2020-12-15 20:29:47 +00:00

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#include "mqtt.h"
#include "arch.h"
#include "base64.h"
#include "event.h"
#include "log.h"
#include "private.h"
#include "url.h"
#include "util.h"
#define MQTT_CLEAN_SESSION 0x02
#define MQTT_HAS_WILL 0x04
#define MQTT_WILL_RETAIN 0x20
#define MQTT_HAS_PASSWORD 0x40
#define MQTT_HAS_USER_NAME 0x80
#define MQTT_GET_WILL_QOS(flags) (((flags) &0x18) >> 3)
#define MQTT_SET_WILL_QOS(flags, qos) (flags) = ((flags) & ~0x18) | ((qos) << 3)
enum { MQTT_OK, MQTT_INCOMPLETE, MQTT_MALFORMED };
struct mqtt_message {
size_t len, topic_offset, topic_len, data_offset, data_len;
uint16_t id;
uint8_t cmd, qos, connack_ret_code;
};
void mg_mqtt_send_header(struct mg_connection *c, uint8_t cmd, uint8_t flags,
uint32_t len) {
uint8_t buf[1 + sizeof(len)], *vlen = &buf[1];
buf[0] = (cmd << 4) | flags;
do {
*vlen = len % 0x80;
len /= 0x80;
if (len > 0) *vlen |= 0x80;
vlen++;
} while (len > 0 && vlen < &buf[sizeof(buf)]);
mg_send(c, buf, vlen - buf);
}
static void mg_send_u16(struct mg_connection *c, uint16_t value) {
mg_send(c, &value, sizeof(value));
}
static void mqtt_login(struct mg_connection *c, const char *url,
struct mg_mqtt_opts *opts) {
uint32_t total_len = 7 + 1 + 2 + 2;
uint16_t flags = (opts->qos & 3) << 3;
struct mg_str user = mg_url_user(url);
struct mg_str pass = mg_url_pass(url);
if (user.len > 0) {
total_len += 2 + (uint32_t) user.len;
flags |= MQTT_HAS_USER_NAME;
}
if (pass.len > 0) {
total_len += 2 + (uint32_t) pass.len;
flags |= MQTT_HAS_PASSWORD;
}
if (opts->will_topic.len > 0 && opts->will_message.len > 0) {
total_len +=
4 + (uint32_t) opts->will_topic.len + (uint32_t) opts->will_message.len;
flags |= MQTT_HAS_WILL;
}
if (opts->clean || opts->client_id.len == 0) flags |= MQTT_CLEAN_SESSION;
if (opts->will_retain) flags |= MQTT_WILL_RETAIN;
total_len += (uint32_t) opts->client_id.len;
mg_mqtt_send_header(c, MQTT_CMD_CONNECT, 0, total_len);
mg_send(c, "\00\04MQTT\04", 7);
mg_send(c, &flags, 1);
// keepalive == 0 means "do not disconnect us!"
mg_send_u16(c, mg_htons((uint16_t) opts->keepalive));
mg_send_u16(c, mg_htons((uint16_t) opts->client_id.len));
mg_send(c, opts->client_id.ptr, opts->client_id.len);
if (flags & MQTT_HAS_WILL) {
mg_send_u16(c, mg_htons((uint16_t) opts->will_topic.len));
mg_send(c, opts->will_topic.ptr, opts->will_topic.len);
mg_send_u16(c, mg_htons((uint16_t) opts->will_message.len));
mg_send(c, opts->will_message.ptr, opts->will_message.len);
}
if (user.len > 0) {
mg_send_u16(c, mg_htons((uint16_t) user.len));
mg_send(c, user.ptr, user.len);
}
if (pass.len > 0) {
mg_send_u16(c, mg_htons((uint16_t) pass.len));
mg_send(c, pass.ptr, pass.len);
}
}
void mg_mqtt_pub(struct mg_connection *c, struct mg_str *topic,
struct mg_str *data) {
uint8_t flags = MQTT_QOS(1);
uint32_t total_len = 2 + (uint32_t) topic->len + (uint32_t) data->len;
LOG(LL_DEBUG, ("%p [%.*s] -> [%.*s]", c->fd, (int) topic->len,
(char *) topic->ptr, (int) data->len, (char *) data->ptr));
if (MQTT_GET_QOS(flags) > 0) total_len += 2;
mg_mqtt_send_header(c, MQTT_CMD_PUBLISH, flags, total_len);
mg_send_u16(c, mg_htons((uint16_t) topic->len));
mg_send(c, topic->ptr, topic->len);
if (MQTT_GET_QOS(flags) > 0) {
static uint16_t s_id;
if (++s_id == 0) s_id++;
mg_send_u16(c, mg_htons(s_id));
}
mg_send(c, data->ptr, data->len);
}
void mg_mqtt_sub(struct mg_connection *c, struct mg_str *topic) {
static uint16_t s_id;
uint8_t qos = 1;
uint32_t total_len = 2 + (uint32_t) topic->len + 2 + 1;
mg_mqtt_send_header(c, MQTT_CMD_SUBSCRIBE, (uint8_t) MQTT_QOS(qos),
total_len);
if (++s_id == 0) ++s_id;
mg_send_u16(c, mg_htons(s_id));
mg_send_u16(c, mg_htons((uint16_t) topic->len));
mg_send(c, topic->ptr, topic->len);
mg_send(c, &qos, sizeof(qos));
}
static int parse(const uint8_t *in, size_t inlen, struct mqtt_message *m) {
uint8_t lc = 0, *p, *end;
uint32_t len = 0, len_len = 0;
memset(m, 0, sizeof(*m));
if (inlen < 2) return MQTT_INCOMPLETE;
m->cmd = in[0] >> 4;
m->qos = (in[0] >> 1) & 3;
len = len_len = 0;
p = (uint8_t *) in + 1;
while ((size_t)(p - in) < inlen) {
lc = *((uint8_t *) p++);
len += (lc & 0x7f) << 7 * len_len;
len_len++;
if (!(lc & 0x80)) break;
if (len_len >= 4) return MQTT_MALFORMED;
}
end = p + len;
if (lc & 0x80 || end > in + inlen) return MQTT_INCOMPLETE;
m->len = (int) (end - in);
switch (m->cmd) {
case MQTT_CMD_CONNACK:
if (end - p < 2) return MQTT_MALFORMED;
m->connack_ret_code = p[1];
break;
case MQTT_CMD_PUBACK:
case MQTT_CMD_PUBREC:
case MQTT_CMD_PUBREL:
case MQTT_CMD_PUBCOMP:
case MQTT_CMD_SUBACK:
if (p + 2 > end) return MQTT_MALFORMED;
m->id = (p[0] << 8) | p[1];
break;
case MQTT_CMD_SUBSCRIBE: {
if (p + 2 > end) return MQTT_MALFORMED;
m->id = (p[0] << 8) | p[1];
p += 2;
break;
}
case MQTT_CMD_PUBLISH: {
if (p + 2 > end) return MQTT_MALFORMED;
m->topic_len = (p[0] << 8) | p[1];
m->topic_offset = p + 2 - in;
p += 2 + m->topic_len;
if (p > end) return MQTT_MALFORMED;
if (m->qos > 0) {
if (p + 2 > end) return MQTT_MALFORMED;
m->id = (p[0] << 8) | p[1];
p += 2;
}
if (p > end) return MQTT_MALFORMED;
m->data_offset = p - in;
m->data_len = end - p;
break;
}
default:
break;
}
return MQTT_OK;
}
int mg_mqtt_next_sub(struct mg_mqtt_message *msg, struct mg_str *topic,
uint8_t *qos, int pos) {
unsigned char *buf = (unsigned char *) msg->dgram.ptr + pos;
int new_pos;
if ((size_t) pos >= msg->dgram.len) return -1;
topic->len = buf[0] << 8 | buf[1];
topic->ptr = (char *) buf + 2;
new_pos = pos + 2 + topic->len + 1;
if ((size_t) new_pos > msg->dgram.len) return -1;
*qos = buf[2 + topic->len];
return new_pos;
}
int mg_mqtt_parse(const unsigned char *s, int n, struct mg_mqtt_message *mm) {
struct mqtt_message m;
int rc = parse(s, n, &m);
if (rc == MQTT_OK) {
mm->dgram.ptr = (char *) s;
mm->dgram.len = m.len;
mm->topic.ptr = (char *) s + m.topic_offset;
mm->topic.len = m.topic_len;
mm->data.ptr = (char *) s + m.data_offset;
mm->data.len = m.data_len;
mm->id = m.id;
mm->cmd = m.cmd;
mm->qos = m.qos;
mm->ack = m.connack_ret_code;
}
return rc;
}
static void mqtt_cb(struct mg_connection *c, int ev, void *ev_data,
void *fn_data) {
if (ev == MG_EV_READ) {
for (;;) {
struct mg_mqtt_message mm;
int rc = mg_mqtt_parse(c->recv.buf, c->recv.len, &mm);
LOG(LL_DEBUG, ("rc %d", rc));
if (rc == MQTT_MALFORMED) {
LOG(LL_ERROR, ("%p MQTT malformed message", c->fd));
c->is_closing = 1;
break;
} else if (rc == MQTT_OK) {
LOG(LL_VERBOSE_DEBUG,
("%p MQTT CMD %d len %d [%.*s]", c->fd, mm.cmd, (int) mm.dgram.len,
(int) mm.data.len, mm.data.ptr));
switch (mm.cmd) {
case MQTT_CMD_CONNACK:
mg_call(c, MG_EV_MQTT_OPEN, &mm.ack);
if (mm.ack == 0) {
LOG(LL_INFO, ("%p Connected", c->fd));
} else {
LOG(LL_ERROR, ("%p MQTT auth failed, code %d", c->fd, mm.ack));
c->is_closing = 1;
}
break;
case MQTT_CMD_PUBLISH: {
LOG(LL_DEBUG, ("%p [%.*s] -> [%.*s]", c->fd, (int) mm.topic.len,
mm.topic.ptr, (int) mm.data.len, mm.data.ptr));
mg_call(c, MG_EV_MQTT_MSG, &mm);
break;
}
}
mg_call(c, MG_EV_MQTT_CMD, &mm);
mg_iobuf_delete(&c->recv, mm.dgram.len);
} else {
break;
}
}
}
(void) ev_data;
(void) fn_data;
}
struct mg_connection *mg_mqtt_connect(struct mg_mgr *mgr, const char *url,
struct mg_mqtt_opts *opts,
mg_event_handler_t fn, void *fn_data) {
struct mg_connection *c = mg_connect(mgr, url, fn, fn_data);
if (c != NULL) {
struct mg_mqtt_opts empty;
memset(&empty, 0, sizeof(empty));
mqtt_login(c, url, opts == NULL ? &empty : opts);
c->pfn = mqtt_cb;
}
return c;
}
struct mg_connection *mg_mqtt_listen(struct mg_mgr *mgr, const char *url,
mg_event_handler_t fn, void *fn_data) {
struct mg_connection *c = mg_listen(mgr, url, fn, fn_data);
if (c != NULL) c->pfn = mqtt_cb, c->pfn_data = mgr;
return c;
}
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