Address review: use long long for package length, make mqtt_next_mid per-client and thread-safe

Co-authored-by: ithewei <26049660+ithewei@users.noreply.github.com>

Author: Copilot

event/unpack.c

@@ -157,9 +157,15 @@ int hio_unpack_by_length_field(hio_t* io, void* buf, int readbytes) {
             hio_close(io);
             return -1;
         }
-        int signed_package_len = (int)head_len + (int)body_len + setting->length_adjustment;
-        if (signed_package_len <= 0 || signed_package_len > (int)setting->package_max_length) {
-            hloge("Invalid package length %d!", signed_package_len);
+        long long signed_package_len = (long long)head_len + (long long)body_len + setting->length_adjustment;
+        if (signed_package_len <= 0) {
+            hloge("Invalid package length %lld!", signed_package_len);
+            io->error = ERR_INVALID_PACKAGE;
+            hio_close(io);
+            return -1;
+        }
+        if (signed_package_len > setting->package_max_length) {
+            hloge("Package length over %u bytes!", setting->package_max_length);
             io->error = ERR_OVER_LIMIT;
             hio_close(io);
             return -1;

mqtt/mqtt_client.c

@@ -6,10 +6,12 @@
 #include "hsocket.h"
 #include "hmath.h"
 
-static unsigned short mqtt_next_mid() {
-    static unsigned short s_mid = 0;
-    if (++s_mid == 0) s_mid = 1;
-    return s_mid;
+static unsigned short mqtt_next_mid(mqtt_client_t* cli) {
+    hmutex_lock(&cli->mutex_);
+    if (++cli->mid_ == 0) cli->mid_ = 1;
+    unsigned short mid = cli->mid_;
+    hmutex_unlock(&cli->mutex_);
+    return mid;
 }
 
 static int mqtt_client_send(mqtt_client_t* cli, const void* buf, int len) {
@@ -629,7 +631,7 @@ int mqtt_client_publish(mqtt_client_t* cli, mqtt_message_t* msg) {
     PUSH16(p, topic_len);
     PUSH_N(p, msg->topic, topic_len);
     if (msg->qos) {
-        mid = mqtt_next_mid();
+        mid = mqtt_next_mid(cli);
         PUSH16(p, mid);
     }
     // MQTT v5: publish properties (empty)
@@ -672,7 +674,7 @@ int mqtt_client_subscribe(mqtt_client_t* cli, const char* topic, int qos) {
     unsigned char* p = buf;
     int headlen = mqtt_head_pack(&head, p);
     p += headlen;
-    unsigned short mid = mqtt_next_mid();
+    unsigned short mid = mqtt_next_mid(cli);
     PUSH16(p, mid);
     // MQTT v5: subscribe properties (empty)
     if (cli->protocol_version == MQTT_PROTOCOL_V5) {
@@ -706,7 +708,7 @@ int mqtt_client_unsubscribe(mqtt_client_t* cli, const char* topic) {
     unsigned char* p = buf;
     int headlen = mqtt_head_pack(&head, p);
     p += headlen;
-    unsigned short mid = mqtt_next_mid();
+    unsigned short mid = mqtt_next_mid(cli);
     PUSH16(p, mid);
     // MQTT v5: unsubscribe properties (empty)
     if (cli->protocol_version == MQTT_PROTOCOL_V5) {

mqtt/mqtt_client.h

@@ -53,6 +53,7 @@ struct mqtt_client_s {
     hssl_ctx_t ssl_ctx;
     // thread-safe
     hmutex_t mutex_;
+    unsigned short mid_;
 };
 
 BEGIN_EXTERN_C