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mongoose/src/mqtt.c
cpq 3c9e218d07 Nits
2023-07-19 05:08:28 +01:00

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#include "mqtt.h"
#include "arch.h"
#include "base64.h"
#include "event.h"
#include "log.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
struct mg_mqtt_pmap {
uint8_t id;
uint8_t type;
};
static const struct mg_mqtt_pmap s_prop_map[] = {
{MQTT_PROP_PAYLOAD_FORMAT_INDICATOR, MQTT_PROP_TYPE_BYTE},
{MQTT_PROP_MESSAGE_EXPIRY_INTERVAL, MQTT_PROP_TYPE_INT},
{MQTT_PROP_CONTENT_TYPE, MQTT_PROP_TYPE_STRING},
{MQTT_PROP_RESPONSE_TOPIC, MQTT_PROP_TYPE_STRING},
{MQTT_PROP_CORRELATION_DATA, MQTT_PROP_TYPE_BINARY_DATA},
{MQTT_PROP_SUBSCRIPTION_IDENTIFIER, MQTT_PROP_TYPE_VARIABLE_INT},
{MQTT_PROP_SESSION_EXPIRY_INTERVAL, MQTT_PROP_TYPE_INT},
{MQTT_PROP_ASSIGNED_CLIENT_IDENTIFIER, MQTT_PROP_TYPE_STRING},
{MQTT_PROP_SERVER_KEEP_ALIVE, MQTT_PROP_TYPE_SHORT},
{MQTT_PROP_AUTHENTICATION_METHOD, MQTT_PROP_TYPE_STRING},
{MQTT_PROP_AUTHENTICATION_DATA, MQTT_PROP_TYPE_BINARY_DATA},
{MQTT_PROP_REQUEST_PROBLEM_INFORMATION, MQTT_PROP_TYPE_BYTE},
{MQTT_PROP_WILL_DELAY_INTERVAL, MQTT_PROP_TYPE_INT},
{MQTT_PROP_REQUEST_RESPONSE_INFORMATION, MQTT_PROP_TYPE_BYTE},
{MQTT_PROP_RESPONSE_INFORMATION, MQTT_PROP_TYPE_STRING},
{MQTT_PROP_SERVER_REFERENCE, MQTT_PROP_TYPE_STRING},
{MQTT_PROP_REASON_STRING, MQTT_PROP_TYPE_STRING},
{MQTT_PROP_RECEIVE_MAXIMUM, MQTT_PROP_TYPE_SHORT},
{MQTT_PROP_TOPIC_ALIAS_MAXIMUM, MQTT_PROP_TYPE_SHORT},
{MQTT_PROP_TOPIC_ALIAS, MQTT_PROP_TYPE_SHORT},
{MQTT_PROP_MAXIMUM_QOS, MQTT_PROP_TYPE_BYTE},
{MQTT_PROP_RETAIN_AVAILABLE, MQTT_PROP_TYPE_BYTE},
{MQTT_PROP_USER_PROPERTY, MQTT_PROP_TYPE_STRING_PAIR},
{MQTT_PROP_MAXIMUM_PACKET_SIZE, MQTT_PROP_TYPE_INT},
{MQTT_PROP_WILDCARD_SUBSCRIPTION_AVAILABLE, MQTT_PROP_TYPE_BYTE},
{MQTT_PROP_SUBSCRIPTION_IDENTIFIER_AVAILABLE, MQTT_PROP_TYPE_BYTE},
{MQTT_PROP_SHARED_SUBSCRIPTION_AVAILABLE, MQTT_PROP_TYPE_BYTE}};
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] = (uint8_t) ((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, (size_t) (vlen - buf));
}
static void mg_send_u16(struct mg_connection *c, uint16_t value) {
mg_send(c, &value, sizeof(value));
}
static void mg_send_u32(struct mg_connection *c, uint32_t value) {
mg_send(c, &value, sizeof(value));
}
static uint8_t varint_size(size_t length) {
uint8_t bytes_needed = 0;
do {
bytes_needed++;
length /= 0x80;
} while (length > 0);
return bytes_needed;
}
static size_t encode_varint(uint8_t *buf, size_t value) {
size_t len = 0;
do {
uint8_t byte = (uint8_t) (value % 128);
value /= 128;
if (value > 0) byte |= 0x80;
buf[len++] = byte;
} while (value > 0);
return len;
}
static size_t decode_varint(const uint8_t *buf, size_t len, size_t *value) {
size_t multiplier = 1, offset;
*value = 0;
for (offset = 0; offset < 4 && offset < len; offset++) {
uint8_t encoded_byte = buf[offset];
*value += (encoded_byte & 0x7f) * multiplier;
multiplier *= 128;
if ((encoded_byte & 0x80) == 0) return offset + 1;
}
return 0;
}
static int mqtt_prop_type_by_id(uint8_t prop_id) {
size_t i, num_properties = sizeof(s_prop_map) / sizeof(s_prop_map[0]);
for (i = 0; i < num_properties; ++i) {
if (s_prop_map[i].id == prop_id) return s_prop_map[i].type;
}
return -1; // Property ID not found
}
// Returns the size of the properties section, without the
// size of the content's length
static size_t get_properties_length(struct mg_mqtt_prop *props, size_t count) {
size_t i, size = 0;
for (i = 0; i < count; i++) {
size++; // identifier
switch (mqtt_prop_type_by_id(props[i].id)) {
case MQTT_PROP_TYPE_STRING_PAIR:
size += (uint32_t) (props[i].val.len + props[i].key.len +
2 * sizeof(uint16_t));
break;
case MQTT_PROP_TYPE_STRING:
size += (uint32_t) (props[i].val.len + sizeof(uint16_t));
break;
case MQTT_PROP_TYPE_BINARY_DATA:
size += (uint32_t) (props[i].val.len + sizeof(uint16_t));
break;
case MQTT_PROP_TYPE_VARIABLE_INT:
size += varint_size((uint32_t) props[i].iv);
break;
case MQTT_PROP_TYPE_INT:
size += (uint32_t) sizeof(uint32_t);
break;
case MQTT_PROP_TYPE_SHORT:
size += (uint32_t) sizeof(uint16_t);
break;
case MQTT_PROP_TYPE_BYTE:
size += (uint32_t) sizeof(uint8_t);
break;
default:
return size; // cannot parse further down
}
}
return size;
}
// returns the entire size of the properties section, including the
// size of the variable length of the content
static size_t get_props_size(struct mg_mqtt_prop *props, size_t count) {
size_t size = get_properties_length(props, count);
size += varint_size(size);
return size;
}
static void mg_send_mqtt_properties(struct mg_connection *c,
struct mg_mqtt_prop *props, size_t nprops) {
size_t total_size = get_properties_length(props, nprops);
uint8_t buf_v[4] = {0, 0, 0, 0};
uint8_t buf[4] = {0, 0, 0, 0};
size_t i, len = encode_varint(buf, total_size);
mg_send(c, buf, (size_t) len);
for (i = 0; i < nprops; i++) {
mg_send(c, &props[i].id, sizeof(props[i].id));
switch (mqtt_prop_type_by_id(props[i].id)) {
case MQTT_PROP_TYPE_STRING_PAIR:
mg_send_u16(c, mg_htons((uint16_t) props[i].key.len));
mg_send(c, props[i].key.ptr, props[i].key.len);
mg_send_u16(c, mg_htons((uint16_t) props[i].val.len));
mg_send(c, props[i].val.ptr, props[i].val.len);
break;
case MQTT_PROP_TYPE_BYTE:
mg_send(c, &props[i].iv, sizeof(uint8_t));
break;
case MQTT_PROP_TYPE_SHORT:
mg_send_u16(c, mg_htons((uint16_t) props[i].iv));
break;
case MQTT_PROP_TYPE_INT:
mg_send_u32(c, mg_htonl((uint32_t) props[i].iv));
break;
case MQTT_PROP_TYPE_STRING:
mg_send_u16(c, mg_htons((uint16_t) props[i].val.len));
mg_send(c, props[i].val.ptr, props[i].val.len);
break;
case MQTT_PROP_TYPE_BINARY_DATA:
mg_send_u16(c, mg_htons((uint16_t) props[i].val.len));
mg_send(c, props[i].val.ptr, props[i].val.len);
break;
case MQTT_PROP_TYPE_VARIABLE_INT:
len = encode_varint(buf_v, props[i].iv);
mg_send(c, buf_v, (size_t) len);
break;
}
}
}
size_t mg_mqtt_next_prop(struct mg_mqtt_message *msg, struct mg_mqtt_prop *prop,
size_t ofs) {
uint8_t *i = (uint8_t *) msg->dgram.ptr + msg->props_start + ofs;
uint8_t *end = (uint8_t *) msg->dgram.ptr + msg->dgram.len;
size_t new_pos = ofs, len;
prop->id = i[0];
if (ofs >= msg->dgram.len || ofs >= msg->props_start + msg->props_size)
return 0;
i++, new_pos++;
switch (mqtt_prop_type_by_id(prop->id)) {
case MQTT_PROP_TYPE_STRING_PAIR:
prop->key.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
prop->key.ptr = (char *) i + 2;
i += 2 + prop->key.len;
prop->val.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
prop->val.ptr = (char *) i + 2;
new_pos += 2 * sizeof(uint16_t) + prop->val.len + prop->key.len;
break;
case MQTT_PROP_TYPE_BYTE:
prop->iv = (uint8_t) i[0];
new_pos++;
break;
case MQTT_PROP_TYPE_SHORT:
prop->iv = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
new_pos += sizeof(uint16_t);
break;
case MQTT_PROP_TYPE_INT:
prop->iv = ((uint32_t) i[0] << 24) | ((uint32_t) i[1] << 16) |
((uint32_t) i[2] << 8) | i[3];
new_pos += sizeof(uint32_t);
break;
case MQTT_PROP_TYPE_STRING:
prop->val.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
prop->val.ptr = (char *) i + 2;
new_pos += 2 + prop->val.len;
break;
case MQTT_PROP_TYPE_BINARY_DATA:
prop->val.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
prop->val.ptr = (char *) i + 2;
new_pos += 2 + prop->val.len;
break;
case MQTT_PROP_TYPE_VARIABLE_INT:
len = decode_varint(i, (size_t) (end - i), (size_t *) &prop->iv);
new_pos = (!len) ? 0 : new_pos + len;
break;
default:
new_pos = 0;
}
return new_pos;
}
void mg_mqtt_login(struct mg_connection *c, const struct mg_mqtt_opts *opts) {
char rnd[10], client_id[21];
struct mg_str cid = opts->client_id;
size_t total_len = 7 + 1 + 2 + 2;
uint8_t hdr[8] = {0, 4, 'M', 'Q', 'T', 'T', opts->version, 0};
if (cid.len == 0) {
mg_random(rnd, sizeof(rnd));
mg_hex(rnd, sizeof(rnd), client_id);
client_id[sizeof(client_id) - 1] = '\0';
cid = mg_str(client_id);
}
if (hdr[6] == 0) hdr[6] = 4; // If version is not set, use 4 (3.1.1)
c->is_mqtt5 = hdr[6] == 5; // Set version 5 flag
hdr[7] = (uint8_t) ((opts->qos & 3) << 3); // Connection flags
if (opts->user.len > 0) {
total_len += 2 + (uint32_t) opts->user.len;
hdr[7] |= MQTT_HAS_USER_NAME;
}
if (opts->pass.len > 0) {
total_len += 2 + (uint32_t) opts->pass.len;
hdr[7] |= MQTT_HAS_PASSWORD;
}
if (opts->topic.len > 0 && opts->message.len > 0) {
total_len += 4 + (uint32_t) opts->topic.len + (uint32_t) opts->message.len;
hdr[7] |= MQTT_HAS_WILL;
}
if (opts->clean || cid.len == 0) hdr[7] |= MQTT_CLEAN_SESSION;
if (opts->retain) hdr[7] |= MQTT_WILL_RETAIN;
total_len += (uint32_t) cid.len;
if (c->is_mqtt5) {
total_len += get_props_size(opts->props, opts->num_props);
if (hdr[7] & MQTT_HAS_WILL)
total_len += get_props_size(opts->will_props, opts->num_will_props);
}
mg_mqtt_send_header(c, MQTT_CMD_CONNECT, 0, (uint32_t) total_len);
mg_send(c, hdr, sizeof(hdr));
// keepalive == 0 means "do not disconnect us!"
mg_send_u16(c, mg_htons((uint16_t) opts->keepalive));
if (c->is_mqtt5) mg_send_mqtt_properties(c, opts->props, opts->num_props);
mg_send_u16(c, mg_htons((uint16_t) cid.len));
mg_send(c, cid.ptr, cid.len);
if (hdr[7] & MQTT_HAS_WILL) {
if (c->is_mqtt5)
mg_send_mqtt_properties(c, opts->will_props, opts->num_will_props);
mg_send_u16(c, mg_htons((uint16_t) opts->topic.len));
mg_send(c, opts->topic.ptr, opts->topic.len);
mg_send_u16(c, mg_htons((uint16_t) opts->message.len));
mg_send(c, opts->message.ptr, opts->message.len);
}
if (opts->user.len > 0) {
mg_send_u16(c, mg_htons((uint16_t) opts->user.len));
mg_send(c, opts->user.ptr, opts->user.len);
}
if (opts->pass.len > 0) {
mg_send_u16(c, mg_htons((uint16_t) opts->pass.len));
mg_send(c, opts->pass.ptr, opts->pass.len);
}
}
void mg_mqtt_pub(struct mg_connection *c, const struct mg_mqtt_opts *opts) {
uint8_t flags = (uint8_t) (((opts->qos & 3) << 1) | (opts->retain ? 1 : 0));
size_t len = 2 + opts->topic.len + opts->message.len;
MG_DEBUG(("%lu [%.*s] -> [%.*s]", c->id, (int) opts->topic.len,
(char *) opts->topic.ptr, (int) opts->message.len,
(char *) opts->message.ptr));
if (opts->qos > 0) len += 2;
if (c->is_mqtt5) len += get_props_size(opts->props, opts->num_props);
mg_mqtt_send_header(c, MQTT_CMD_PUBLISH, flags, (uint32_t) len);
mg_send_u16(c, mg_htons((uint16_t) opts->topic.len));
mg_send(c, opts->topic.ptr, opts->topic.len);
if (opts->qos > 0) {
if (++c->mgr->mqtt_id == 0) ++c->mgr->mqtt_id;
mg_send_u16(c, mg_htons(c->mgr->mqtt_id));
}
if (c->is_mqtt5) mg_send_mqtt_properties(c, opts->props, opts->num_props);
mg_send(c, opts->message.ptr, opts->message.len);
}
void mg_mqtt_sub(struct mg_connection *c, const struct mg_mqtt_opts *opts) {
uint8_t qos_ = opts->qos & 3;
size_t plen = c->is_mqtt5 ? get_props_size(opts->props, opts->num_props) : 0;
size_t len = 2 + opts->topic.len + 2 + 1 + plen;
mg_mqtt_send_header(c, MQTT_CMD_SUBSCRIBE, 2, (uint32_t) len);
if (++c->mgr->mqtt_id == 0) ++c->mgr->mqtt_id;
mg_send_u16(c, mg_htons(c->mgr->mqtt_id));
if (c->is_mqtt5) mg_send_mqtt_properties(c, opts->props, opts->num_props);
mg_send_u16(c, mg_htons((uint16_t) opts->topic.len));
mg_send(c, opts->topic.ptr, opts->topic.len);
mg_send(c, &qos_, sizeof(qos_));
}
int mg_mqtt_parse(const uint8_t *buf, size_t len, uint8_t version,
struct mg_mqtt_message *m) {
uint8_t lc = 0, *p, *end;
uint32_t n = 0, len_len = 0;
memset(m, 0, sizeof(*m));
m->dgram.ptr = (char *) buf;
if (len < 2) return MQTT_INCOMPLETE;
m->cmd = (uint8_t) (buf[0] >> 4);
m->qos = (buf[0] >> 1) & 3;
n = len_len = 0;
p = (uint8_t *) buf + 1;
while ((size_t) (p - buf) < len) {
lc = *((uint8_t *) p++);
n += (uint32_t) ((lc & 0x7f) << 7 * len_len);
len_len++;
if (!(lc & 0x80)) break;
if (len_len >= 4) return MQTT_MALFORMED;
}
end = p + n;
if ((lc & 0x80) || (end > buf + len)) return MQTT_INCOMPLETE;
m->dgram.len = (size_t) (end - buf);
switch (m->cmd) {
case MQTT_CMD_CONNACK:
if (end - p < 2) return MQTT_MALFORMED;
m->ack = p[1];
break;
case MQTT_CMD_PUBACK:
case MQTT_CMD_PUBREC:
case MQTT_CMD_PUBREL:
case MQTT_CMD_PUBCOMP:
case MQTT_CMD_SUBSCRIBE:
case MQTT_CMD_SUBACK:
case MQTT_CMD_UNSUBSCRIBE:
case MQTT_CMD_UNSUBACK:
if (p + 2 > end) return MQTT_MALFORMED;
m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
p += 2;
break;
case MQTT_CMD_PUBLISH: {
if (p + 2 > end) return MQTT_MALFORMED;
m->topic.len = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
m->topic.ptr = (char *) p + 2;
p += 2 + m->topic.len;
if (p > end) return MQTT_MALFORMED;
if (m->qos > 0) {
if (p + 2 > end) return MQTT_MALFORMED;
m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
p += 2;
}
if (p > end) return MQTT_MALFORMED;
if (version == 5 && p + 2 < end) {
len_len = (uint32_t) decode_varint(p, (size_t) (end - p), &m->props_size);
if (!len_len) return MQTT_MALFORMED;
m->props_start = (size_t) (p + len_len - buf);
p += len_len + m->props_size;
}
if (p > end) return MQTT_MALFORMED;
m->data.ptr = (char *) p;
m->data.len = (size_t) (end - p);
break;
}
default:
break;
}
return MQTT_OK;
}
static void mqtt_cb(struct mg_connection *c, int ev, void *ev_data,
void *fn_data) {
if (ev == MG_EV_READ) {
for (;;) {
uint8_t version = c->is_mqtt5 ? 5 : 4;
struct mg_mqtt_message mm;
int rc = mg_mqtt_parse(c->recv.buf, c->recv.len, version, &mm);
if (rc == MQTT_MALFORMED) {
MG_ERROR(("%lu MQTT malformed message", c->id));
c->is_closing = 1;
break;
} else if (rc == MQTT_OK) {
MG_VERBOSE(("%lu MQTT CMD %d len %d [%.*s]", c->id, 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) {
MG_DEBUG(("%lu Connected", c->id));
} else {
MG_ERROR(("%lu MQTT auth failed, code %d", c->id, mm.ack));
c->is_closing = 1;
}
break;
case MQTT_CMD_PUBLISH: {
MG_DEBUG(("%lu [%.*s] -> [%.*s]", c->id, (int) mm.topic.len,
mm.topic.ptr, (int) mm.data.len, mm.data.ptr));
if (mm.qos > 0) {
uint16_t id = mg_ntohs(mm.id);
uint32_t remaining_len = sizeof(id);
if (c->is_mqtt5) remaining_len += 2; // 3.4.2
mg_mqtt_send_header(
c,
(uint8_t) (mm.qos == 2 ? MQTT_CMD_PUBREC : MQTT_CMD_PUBACK),
0, remaining_len);
mg_send(c, &id, sizeof(id));
if (c->is_mqtt5) {
uint16_t zero = 0;
mg_send(c, &zero, sizeof(zero));
}
}
mg_call(c, MG_EV_MQTT_MSG, &mm); // let the app handle qos stuff
break;
}
case MQTT_CMD_PUBREC: { // MQTT5: 3.5.2-1 TODO(): variable header rc
uint16_t id = mg_ntohs(mm.id);
uint32_t remaining_len = sizeof(id); // MQTT5 3.6.2-1
mg_mqtt_send_header(c, MQTT_CMD_PUBREL, 2, remaining_len);
mg_send(c, &id, sizeof(id)); // MQTT5 3.6.1-1, flags = 2
break;
}
case MQTT_CMD_PUBREL: { // MQTT5: 3.6.2-1 TODO(): variable header rc
uint16_t id = mg_ntohs(mm.id);
uint32_t remaining_len = sizeof(id); // MQTT5 3.7.2-1
mg_mqtt_send_header(c, MQTT_CMD_PUBCOMP, 0, remaining_len);
mg_send(c, &id, sizeof(id));
break;
}
}
mg_call(c, MG_EV_MQTT_CMD, &mm);
mg_iobuf_del(&c->recv, 0, mm.dgram.len);
} else {
break;
}
}
}
(void) ev_data;
(void) fn_data;
}
void mg_mqtt_ping(struct mg_connection *nc) {
mg_mqtt_send_header(nc, MQTT_CMD_PINGREQ, 0, 0);
}
void mg_mqtt_pong(struct mg_connection *nc) {
mg_mqtt_send_header(nc, MQTT_CMD_PINGRESP, 0, 0);
}
void mg_mqtt_disconnect(struct mg_connection *c,
const struct mg_mqtt_opts *opts) {
size_t len = 0;
if (c->is_mqtt5) len = 1 + get_props_size(opts->props, opts->num_props);
mg_mqtt_send_header(c, MQTT_CMD_DISCONNECT, 0, (uint32_t) len);
if (c->is_mqtt5) {
uint8_t zero = 0;
mg_send(c, &zero, sizeof(zero)); // reason code
mg_send_mqtt_properties(c, opts->props, opts->num_props);
}
}
struct mg_connection *mg_mqtt_connect(struct mg_mgr *mgr, const char *url,
const 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));
mg_mqtt_login(c, 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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