Option for user defined varylink

Author: huitema

UnitTest1/unittest1.cpp

@@ -2070,6 +2070,13 @@ namespace UnitTest1
             Assert::AreEqual(ret, 0);
         }
 
+        TEST_METHOD(cc_ns_varylink)
+        {
+            int ret = cc_ns_varylink_test();
+
+            Assert::AreEqual(ret, 0);
+        }
+
         TEST_METHOD(fastcc)
         {
             int ret = fastcc_test();

picohttp_t/picohttp_t.c

@@ -116,7 +116,8 @@ static const picoquic_test_def_t test_table[] = {
     { "cc_ns_drop_and_back", cc_ns_drop_and_back_test },
     { "cc_ns_low_and_up", cc_ns_low_and_up_test },
     { "cc_ns_wifi_fade", cc_ns_wifi_fade_test },
-    { "cc_ns_wifi_suspension", cc_ns_wifi_suspension_test }
+    { "cc_ns_wifi_suspension", cc_ns_wifi_suspension_test },
+    { "cc_ns_varylink", cc_ns_varylink_test }
 };
 
 static size_t const nb_tests = sizeof(test_table) / sizeof(picoquic_test_def_t);

picoquictest/cc_compete_test.c

@@ -219,7 +219,6 @@ int cc_ns_low_and_up_test()
     return picoquic_ns(&spec);
 }
 
-
 /* Check that the picoquic_ns simulations can correctly test the low_and_up scenario.
  */
 int cc_ns_wifi_fade_test()
@@ -267,4 +266,39 @@ int cc_ns_wifi_suspension_test()
     spec.link_scenario = link_scenario_wifi_suspension;
 
     return picoquic_ns(&spec);
-}
+}
+
+
+/* Check that the picoquic_ns simulations can correctly test the low_and_up scenario.
+* The simple scenario merely duplicates the "wifi fade" scenario, the only difference
+* being that the "varylink" structure is user specified.
+*/
+picoquic_ns_link_spec_t cc_varylink_test_spec[] = {
+    { 1000000,  0.01,  0.01, 5000, 0, 15000, 0 },
+    { 2000000,  0.001,  0.001, 5000, 0, 15000, 0 },
+    { UINT64_MAX,  0.01,  0.01, 5000, 0, 15000, 0 }
+};
+
+int cc_ns_varylink_test()
+{
+    picoquic_ns_spec_t spec = { 0 };
+    picoquic_connection_id_t icid = { { 0xcc, 0x11, 0xbb, 0, 0, 0, 0, 0}, 8 };
+    spec.main_cc_algo = picoquic_bbr_algorithm;
+    spec.main_start_time = 0;
+    spec.main_scenario_text = cc_compete_batch_scenario_4M;
+    spec.background_cc_algo = picoquic_bbr_algorithm;
+    spec.background_start_time = 0;
+    spec.background_scenario_text = cc_compete_batch_scenario_10M;
+    spec.nb_connections = 1;
+    spec.data_rate_in_gbps = 0.01;
+    spec.latency = 5000;
+    spec.main_target_time = 7000000;
+    spec.queue_delay_max = 15000;
+    spec.icid = icid;
+    spec.qlog_dir = ".";
+    spec.link_scenario = link_scenario_none;
+    spec.vary_link_nb = sizeof(cc_varylink_test_spec) / sizeof(picoquic_ns_link_spec_t);
+    spec.vary_link_spec = cc_varylink_test_spec;
+
+    return picoquic_ns(&spec);
+}

picoquictest/picoquic_ns.c

@@ -62,12 +62,18 @@
 * default callback function for the server context. When a new connection
 * arrives, the server uses the "cc_compete" context to find the matching
 * client connection, discover the desired congestion algorithm, and
-* program it in the server side connection context
+* program it in the server side connection context.
 * 
 * The main advantages of this simulation are:
 * - Running the actual picoquic code.
 * - Operating in "virtual time", much faster than "real time".
 * 
+* We can simulate a link with a capacity and a latency varies over time. The
+* API provides two ways to do that:
+* 
+* - either pick one of the predefines variation scenarios, such as `blackhole`
+* - or provide an array of 
+* 
 * There are limits to this setup:
 * - we set a maximum number of nodes, links, connections. This is not strictly
 *   necessary. We could dynamically allocate arrays.
@@ -100,24 +106,14 @@ typedef struct st_picoquic_ns_client_t {
     picoquic_connection_id_t icid;
 } picoquic_ns_client_t;
 
-typedef struct st_picoquic_ns_link_spec_t {
-    uint64_t duration;
-    double data_rate_in_gbps_up; /* datarate, server to clients, defaults to 10 mbps */
-    double data_rate_in_gbps_down; /* datarate, server to clients, defaults to 10 mbps */
-    uint64_t latency; /* one way latency, microseconds, both directions */
-    uint64_t jitter; /* delay jitter, microseconds, both directions */
-    uint64_t queue_delay_max; /* if specified, specify the max buffer queuing for the link, in microseconds */
-    uint64_t l4s_max; /* if specified, specify the max buffer queuing for the link, in microseconds */
-} picoquic_ns_link_spec_t;
-
-
 typedef struct st_picoquic_ns_ctx_t {
     picoquic_quic_t* q_ctx[PICOQUIC_NS_NB_NODES];
     struct sockaddr_in addr[PICOQUIC_NS_NB_NODES];
     picoquictest_sim_link_t* link[PICOQUIC_NS_NB_LINKS];
     uint64_t simulated_time;
     int nb_connections;
     picoquic_ns_link_spec_t* vary_link_spec;
+    int vary_link_is_user_provided;
     size_t vary_link_nb;
     uint64_t next_vary_link_time;
     size_t vary_link_index;
@@ -267,58 +263,65 @@ int picoquic_ns_create_default_link_spec(picoquic_ns_ctx_t* cc_ctx, picoquic_ns_
 
 int picoquic_ns_create_link_spec(picoquic_ns_ctx_t* cc_ctx, picoquic_ns_spec_t* spec)
 {
-    int ret;
+    int ret = 0;
 
-    switch (spec->link_scenario) {
-    case link_scenario_none:
-        ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 1);
-        break;
-    case link_scenario_black_hole:
-        if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 3)) == 0) {
-            cc_ctx->vary_link_spec[0].duration = 2000000;
-            cc_ctx->vary_link_spec[1].duration = 2000000;
-            cc_ctx->vary_link_spec[2].duration = UINT64_MAX;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_down = 0;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_up = 0;
-        }
-        break;
-    case link_scenario_drop_and_back:
-        if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 3)) == 0) {
-            cc_ctx->vary_link_spec[0].duration = 1500000;
-            cc_ctx->vary_link_spec[1].duration = 2000000;
-            cc_ctx->vary_link_spec[2].duration = UINT64_MAX;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_down *= 0.5;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_up *= 0.5;
-        }
-        break;
-    case link_scenario_low_and_up:
-        if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 2)) == 0) {
-            cc_ctx->vary_link_spec[0].duration = 2500000;
-            cc_ctx->vary_link_spec[0].data_rate_in_gbps_down *= 0.5;
-            cc_ctx->vary_link_spec[0].data_rate_in_gbps_up *= 0.5;
-            cc_ctx->vary_link_spec[1].duration = UINT64_MAX;
-        }
-        break;
-    case link_scenario_wifi_fade:
-        if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 3)) == 0) {
-            cc_ctx->vary_link_spec[0].duration = 1000000;
-            cc_ctx->vary_link_spec[1].duration = 2000000;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_down *= 0.1;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_up *= 0.1;
-            cc_ctx->vary_link_spec[2].duration = UINT64_MAX;
-        }
-        break;
-    case link_scenario_wifi_suspension:
-        if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 2)) == 0) {
-            cc_ctx->vary_link_spec[0].duration = 1800000;
-            cc_ctx->vary_link_spec[1].duration = 200000;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_down = 0;
-            cc_ctx->vary_link_spec[1].data_rate_in_gbps_up = 0;
+    if (spec->vary_link_nb > 0) {
+        cc_ctx->vary_link_is_user_provided = 1;
+        cc_ctx->vary_link_nb = spec->vary_link_nb;
+        cc_ctx->vary_link_spec = spec->vary_link_spec;
+    }
+    else {
+        switch (spec->link_scenario) {
+        case link_scenario_none:
+            ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 1);
+            break;
+        case link_scenario_black_hole:
+            if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 3)) == 0) {
+                cc_ctx->vary_link_spec[0].duration = 2000000;
+                cc_ctx->vary_link_spec[1].duration = 2000000;
+                cc_ctx->vary_link_spec[2].duration = UINT64_MAX;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_down = 0;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_up = 0;
+            }
+            break;
+        case link_scenario_drop_and_back:
+            if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 3)) == 0) {
+                cc_ctx->vary_link_spec[0].duration = 1500000;
+                cc_ctx->vary_link_spec[1].duration = 2000000;
+                cc_ctx->vary_link_spec[2].duration = UINT64_MAX;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_down *= 0.5;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_up *= 0.5;
+            }
+            break;
+        case link_scenario_low_and_up:
+            if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 2)) == 0) {
+                cc_ctx->vary_link_spec[0].duration = 2500000;
+                cc_ctx->vary_link_spec[0].data_rate_in_gbps_down *= 0.5;
+                cc_ctx->vary_link_spec[0].data_rate_in_gbps_up *= 0.5;
+                cc_ctx->vary_link_spec[1].duration = UINT64_MAX;
+            }
+            break;
+        case link_scenario_wifi_fade:
+            if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 3)) == 0) {
+                cc_ctx->vary_link_spec[0].duration = 1000000;
+                cc_ctx->vary_link_spec[1].duration = 2000000;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_down *= 0.1;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_up *= 0.1;
+                cc_ctx->vary_link_spec[2].duration = UINT64_MAX;
+            }
+            break;
+        case link_scenario_wifi_suspension:
+            if ((ret = picoquic_ns_create_default_link_spec(cc_ctx, spec, 2)) == 0) {
+                cc_ctx->vary_link_spec[0].duration = 1800000;
+                cc_ctx->vary_link_spec[1].duration = 200000;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_down = 0;
+                cc_ctx->vary_link_spec[1].data_rate_in_gbps_up = 0;
+            }
+            break;
+        default:
+            ret = -1;
+            break;
         }
-        break;
-    default:
-        ret = -1;
-        break;
     }
     return ret;
 }
@@ -357,7 +360,8 @@ int picoquic_ns_create_links(picoquic_ns_ctx_t* cc_ctx, picoquic_ns_spec_t* spec
         }
     }
 
-    /* program the first transition if needed -- but this should be automatic */
+    /* The simulation will automatically execute the transition to
+     * the first "vary_link_spec" value. */
 
     return ret;
 }
@@ -389,8 +393,11 @@ void picoquic_ns_delete_ctx(picoquic_ns_ctx_t* cc_ctx)
 
     /* delete the link specifications */
     if (cc_ctx->vary_link_spec != NULL) {
-        free(cc_ctx->vary_link_spec);
+        if (!cc_ctx->vary_link_is_user_provided) {
+            free(cc_ctx->vary_link_spec);
+        }
         cc_ctx->vary_link_spec = NULL;
+        cc_ctx->vary_link_nb = 0;
     }
     /* and then free the context itself */
     free(cc_ctx);

picoquictest/picoquic_ns.h

@@ -45,6 +45,16 @@ typedef enum {
     link_scenario_wifi_suspension
 } picoquic_ns_link_scenario_enum;
 
+typedef struct st_picoquic_ns_link_spec_t {
+    uint64_t duration;
+    double data_rate_in_gbps_up; /* datarate, server to clients, defaults to 10 mbps */
+    double data_rate_in_gbps_down; /* datarate, server to clients, defaults to 10 mbps */
+    uint64_t latency; /* one way latency, microseconds, both directions */
+    uint64_t jitter; /* delay jitter, microseconds, both directions */
+    uint64_t queue_delay_max; /* if specified, specify the max buffer queuing for the link, in microseconds */
+    uint64_t l4s_max; /* if specified, specify the max buffer queuing for the link, in microseconds */
+} picoquic_ns_link_spec_t;
+
 typedef struct st_picoquic_ns_spec_t {
     uint64_t main_start_time;
     uint64_t main_target_time;
@@ -62,7 +72,15 @@ typedef struct st_picoquic_ns_spec_t {
     uint64_t l4s_max; /* if specified, specify the max buffer queuing for the link, in microseconds */
     picoquic_connection_id_t icid; /* if specified, set the ICID of connections. Last byte will be overwriten by connection number */
     char const* qlog_dir; /* if specified, set the qlog directory, and request qlog traces. */
+    /* The specification can either specify one of the preprogrammed link scenarios,
+     * or provide an array of varylink items specifying the variations of the link.
+     * If "vary_link==0", the simulation will use the specified scenario.
+     * If "vary_link_nb" is larger than zero, the simulation will use the provided
+     * array "vary_link_spec" and ignore the "link_scenario" value.
+     */
     picoquic_ns_link_scenario_enum link_scenario; /* specify link transition scenario if needed */
+    size_t vary_link_nb; /* Number of "vary_link" items */
+    picoquic_ns_link_spec_t* vary_link_spec; /* one item for each of the successive states of the link. */
 } picoquic_ns_spec_t;
 
 int picoquic_ns(picoquic_ns_spec_t* spec);

picoquictest/picoquictest.h

@@ -280,6 +280,7 @@ int cc_ns_drop_and_back_test();
 int cc_ns_low_and_up_test();
 int cc_ns_wifi_fade_test();
 int cc_ns_wifi_suspension_test();
+int cc_ns_varylink_test();
 int satellite_basic_test();
 int satellite_seeded_test();
 int satellite_seeded_bbr1_test();