fix uasync set_timeout(0) ordering, dummynet shaper initial delay, add tests

- uasync_set_timeout(0): use FIFO immediate_queue instead of timeout_heap
  to guarantee execution AFTER all currently-expired heap timers
- uasync_cancel_timeout: search immediate_queue for timeout=0 timers
- dummynet: start initial shaper with bandwidth-based delay instead of 0
  (prevents queue from never filling up when packets arrive sequentially)
- test_dummynet: rename get_time_us -> now_us (conflict with u_async.h)
- test_u_async_comprehensive: fix immediate_timeouts, add timeout_ordering test

lib/u_async.c

@@ -531,6 +531,15 @@ void* uasync_set_timeout(struct UASYNC* ua, int timeout_tb, void* arg, timeout_c
     node->callback = callback;
     node->ua = ua;
 
+    if (timeout_tb == 0) {
+        node->expiration_ms = 0;
+        node->next = NULL;
+        if (ua->immediate_queue_tail) ua->immediate_queue_tail->next = node;
+        else ua->immediate_queue_head = node;
+        ua->immediate_queue_tail = node;
+        return node;
+    }
+    
     // Calculate expiration time in milliseconds
     struct timeval now;
     get_current_time(&now);
@@ -614,7 +623,18 @@ err_t uasync_cancel_timeout(struct UASYNC* ua, void* t_id) {
     DEBUG_DEBUG(DEBUG_CATEGORY_TIMERS, "uasync_cancel_timeout: not found in heap: ua=%p, t_id=%p, node=%p, expires=%llu ms", 
                 ua, t_id, node, (unsigned long long)node->expiration_ms);
 
-    // If not found in heap, it may have already expired or been invalid
+    // Not in heap — try immediate_queue (for timeout=0 timers placed via FIFO)
+    {
+        struct timeout_node* cur = ua->immediate_queue_head;
+        while (cur) {
+            if (cur == node) {
+                cur->callback = NULL;
+                return ERR_OK;
+            }
+            cur = cur->next;
+        }
+    }
+
     return ERR_FAIL;
 }
 

src/dummynet.c

@@ -131,7 +131,6 @@ static void dummynet_process_queue(struct dummynet* dn, int dir_idx) {
     }
 
     struct dummynet_pkt* pkt = (struct dummynet_pkt*)entry->data;
-
     ssize_t n = socket_sendto(dn->sock, pkt->data, pkt->len,
                               (struct sockaddr*)&dir->dest_addr, dir->dest_len);
     if (n < 0) {
@@ -327,7 +326,15 @@ static void dummynet_delay_callback(void* user_arg) {
         if (sarg) {
             sarg->dn = dn;
             sarg->dir_idx = dir_idx;
-            dir->shaper_timer = uasync_set_timeout(dn->ua, 0, sarg, dummynet_shaper_callback, "dummynet_shaper0");
+            int shaper_delay_tb = 0;
+            if (dir->bandwidth_kbps > 0) {
+                uint64_t delay_calc = (uint64_t)pkt->len * 80ULL / (uint64_t)dir->bandwidth_kbps;
+                shaper_delay_tb = (int)delay_calc;
+                if (shaper_delay_tb == 0) shaper_delay_tb = 1;
+            }
+            dir->shaper_timer = uasync_set_timeout(dn->ua, shaper_delay_tb, sarg, dummynet_shaper_callback, "dummynet_shaper0");
+            if (dir->shaper_timer) dir->shaper_timer_set++;
+            else { u_free(sarg); dir->shaper_pending = 0; }
         } else {
             dir->shaper_pending = 0;
         }

tests/test_dummynet.c

@@ -60,7 +60,7 @@ struct test_state {
     int passed;
 };
 
-static inline uint64_t get_time_us(void) {
+static inline uint64_t now_us(void) {
     struct timeval tv;
     gettimeofday(&tv, NULL);
     return (uint64_t)tv.tv_sec * 1000000ULL + tv.tv_usec;
@@ -75,7 +75,7 @@ static void send_one_packet(struct test_state* st, uint32_t seq) {
     uint16_t data_len = MIN_PKT_SIZE + (rand() % (max_data_len - MIN_PKT_SIZE + 1));
     
     pkt->seq_num = seq;
-    pkt->send_time_us = get_time_us();
+    pkt->send_time_us = now_us();
     pkt->data_len = data_len;
     
     /* Заполняем данные */
@@ -95,7 +95,7 @@ static void send_one_packet(struct test_state* st, uint32_t seq) {
     
     /* B -> dummynet (backward) */
     pkt->seq_num = seq + 10000; /* Отличаем пакеты от B */
-    pkt->send_time_us = get_time_us();
+    pkt->send_time_us = now_us();
     socket_sendto(st->sock_b, buf, sizeof(*pkt) + data_len,
                   (struct sockaddr*)&dest, sizeof(dest));
 }
@@ -136,7 +136,7 @@ static void recv_callback_a(socket_t sock, void* arg) {
     if (n < (ssize_t)sizeof(struct test_pkt)) return;
     
     struct test_pkt* pkt = (struct test_pkt*)buf;
-    uint64_t now = get_time_us();
+    uint64_t now = now_us();
     uint64_t latency = now - pkt->send_time_us;
     
     st->recv_a++;
@@ -155,7 +155,7 @@ static void recv_callback_b(socket_t sock, void* arg) {
     if (n < (ssize_t)sizeof(struct test_pkt)) return;
     
     struct test_pkt* pkt = (struct test_pkt*)buf;
-    uint64_t now = get_time_us();
+    uint64_t now = now_us();
     uint64_t latency = now - pkt->send_time_us;
     
     st->recv_b++;
@@ -262,7 +262,7 @@ static int run_scenario(const char* name,
     st.send_timer = uasync_set_timeout(st.ua, 1, &st, send_timer_callback, "test_dummynet");
     
     /* Умное ожидание завершения: ранний выход при готовности + watchdog */
-    uint64_t start_time = get_time_us();
+    uint64_t start_time = now_us();
     uint64_t watchdog_start = 0;  /* Стартует после отправки всех пакетов */
     int watchdog_active = 0;
     const uint64_t WATCHDOG_US = 3000000ULL;  /* 3 секунды максимум после отправки */
@@ -273,7 +273,7 @@ static int run_scenario(const char* name,
     while (1) {
         uasync_poll(st.ua, 1);  /* 0.1ms timeout - чаще для обработки таймеров */
         
-        uint64_t now = get_time_us();
+        uint64_t now = now_us();
         
         /* Активируем watchdog когда все пакеты отправлены */
         if (!watchdog_active && st.next_seq >= PKT_COUNT) {

tests/test_u_async_comprehensive.c

@@ -242,14 +242,9 @@ static void test_immediate_timeouts(void) {
         ASSERT_NOT_NULL(timer, "Failed to set immediate timer");
     }
     
-    /* Immediate timeouts should fire during next poll */
+    /* Immediate (timeout=0) callbacks use FIFO queue — all fire in first poll */
     ASSERT_EQ(ctx.callback_count, 0, "Callbacks fired too early");
-    
-    /* Note: Library processes only one timeout per poll, so we need multiple polls */
-    for (int i = 0; i < 5; i++) {
-        uasync_poll(ua, 1);  /* Minimal poll */
-    }
-    
+    uasync_poll(ua, 1);
     ASSERT_EQ(ctx.callback_count, ctx.expected_count, "Immediate timeouts didn't fire correctly");
     
     /* Check that exactly 5 new immediate timeouts were recorded */
@@ -260,6 +255,48 @@ static void test_immediate_timeouts(void) {
     TEST_PASS();
 }
 
+/* Test 3b: Timeout ordering — timeout=0 set during callback fires AFTER all expired heap timers */
+struct ordering_ctx {
+    int seq[8];
+    int idx;
+    uasync_t* ua;
+};
+
+static void order_immediate_cb(void* arg);
+
+static void order_delayed_cb(void* arg) {
+    struct ordering_ctx* ctx = (struct ordering_ctx*)arg;
+    ctx->seq[ctx->idx++] = 1;
+    if (ctx->idx == 1) uasync_set_timeout(ctx->ua, 0, ctx, order_immediate_cb, "test_order_imm");
+}
+
+static void order_immediate_cb(void* arg) {
+    struct ordering_ctx* ctx = (struct ordering_ctx*)arg;
+    ctx->seq[ctx->idx++] = 2;
+}
+
+static void test_timeout_ordering(void) {
+    TEST_START("Timeout ordering: immediate after delayed");
+
+    uasync_t* ua = uasync_create();
+    ASSERT_NOT_NULL(ua, "Failed to create uasync instance");
+
+    struct ordering_ctx ctx = {{0}};
+    ctx.ua = ua;
+
+    for (int i = 0; i < 5; i++)
+        ASSERT_NOT_NULL(uasync_set_timeout(ua, 10, &ctx, order_delayed_cb, "test_order_del"), "Failed to set timer");
+
+    for (int i = 0; i < 20 && ctx.idx < 6; i++) uasync_poll(ua, 100); /* 10ms — enough for 1ms delay timers */
+
+    ASSERT_EQ(ctx.idx, 6, "Not all callbacks fired");
+    for (int i = 0; i < 5; i++) ASSERT_EQ(ctx.seq[i], 1, "Delayed callback out of order");
+    ASSERT_EQ(ctx.seq[5], 2, "Immediate callback fired before all delayed");
+
+    uasync_destroy(ua, 0);
+    TEST_PASS();
+}
+
 /* Test 4: Memory leak detection */
 static void test_memory_leak_detection(void) {
     TEST_START("Memory leak detection");
@@ -502,6 +539,7 @@ int main(void) {
     test_basic_timers();
     test_timer_cancellation_races();
     test_immediate_timeouts();
+    test_timeout_ordering();
     test_memory_leak_detection();
     test_socket_management();
     test_error_handling();