fixup: LIT-134 implementing pmtud state machines

src/he/conn.c

@@ -16,21 +16,19 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
-
-#include "conn.h"
-#include "conn_internal.h"
-#include "core.h"
-#include "config.h"
-#include "ssl_ctx.h"
-#include "pmtud.h"
-
 #ifndef WOLFSSL_USER_SETTINGS
 #include <wolfssl/options.h>
 #endif
 #include <wolfssl/error-ssl.h>
 #include <wolfssl/ssl.h>
 #include <wolfssl/wolfcrypt/settings.h>
 
+#include "conn.h"
+#include "conn_internal.h"
+#include "core.h"
+#include "config.h"
+#include "ssl_ctx.h"
+#include "pmtud.h"
 #include "memory.h"
 
 bool he_conn_is_error_fatal(he_conn_t *conn, he_return_code_t error_msg) {
@@ -1189,11 +1187,8 @@ he_return_code_t he_conn_start_pmtu_discovery(he_conn_t *conn) {
     return HE_ERR_INVALID_CONN_STATE;
   }
 
-  // Generate event
-  he_internal_generate_event(conn, HE_EVENT_PMTU_DISCOVERY_STARTED);
-
   // Enter Base state
-  conn->pmtud_state = HE_PMTUD_STATE_BASE;
+  he_internal_change_pmtud_state(conn, HE_PMTUD_STATE_BASE);
 
   return HE_SUCCESS;
 }

src/he/he_internal.h

@@ -227,14 +227,17 @@ struct he_conn {
   /// Identifier of the ping message pending reply
   uint16_t ping_pending_id;
 
-  /// Path MTU Discovery
+  /// Path MTU Discovery state
   he_pmtud_state_t pmtud_state;
 
   /// Current effective PMTU
   uint16_t effective_pmtu;
 
   /// PMTUD internal data
-  uint16_t base_pmtu;
+  uint16_t pmtud_base;
+  uint8_t pmtud_probe_count;
+  uint16_t pmtud_probing_size;
+  bool pmtud_is_using_big_step;
 };
 
 struct he_plugin_chain {

src/he/pmtud.c

@@ -44,6 +44,86 @@ he_return_code_t he_internal_pmtud_send_probe(he_conn_t *conn, uint16_t probe_mt
 void he_internal_pmtud_pong_received(he_conn_t *conn) {
 }
 
+void he_internal_change_pmtud_state(he_conn_t *conn, he_pmtud_state_t state) {
+  if(conn == NULL || conn->pmtud_state == state) {
+    return;
+  }
+
+  switch(conn->state) {
+    case HE_PMTUD_STATE_DISABLED:
+      switch(state) {
+        case HE_PMTUD_STATE_BASE:
+          // DISABLED -> BASE
+          he_internal_generate_event(conn, HE_EVENT_PMTU_DISCOVERY_STARTED);
+
+          // Initialize PMTU internal data
+          conn->pmtud_base = HE_MAX_MTU;
+          conn->pmtud_is_using_big_step = true;
+          conn->pmtud_probe_count = 0;
+
+          // TODO: start timers?
+          break;
+        default:
+          // Invalid state transition, do nothing
+          return;
+      }
+      break;
+    case HE_PMTUD_STATE_BASE:
+      switch(state) {
+        case HE_PMTUD_STATE_SEARCHING:
+          // TODO: enter searching state
+          break;
+        case HE_PMTUD_STATE_ERROR:
+          // TODO: enter error state
+          break;
+        case HE_PMTUD_STATE_SEARCH_COMPLETE:
+          // TODO: enter search complete state
+          break;
+        default:
+          // Invalid state transition, do nothing
+          return;
+      }
+      break;
+    case HE_PMTUD_STATE_SEARCHING:
+      switch(state) {
+        case HE_PMTUD_STATE_BASE:
+          // TODO: Return to Base when blackhole is detected
+          break;
+        case HE_PMTUD_STATE_SEARCH_COMPLETE:
+          // TODO: Probe acked
+          break;
+        default:
+          // Invalid state transition, do nothing
+          return;
+      }
+      break;
+    case HE_PMTUD_STATE_ERROR:
+      switch(state) {
+        case HE_PMTUD_STATE_SEARCHING:
+          // TODO: Enter Searching state when probe succeeds
+          break;
+        default:
+          // Invalid state transition, do nothing
+          return;
+      }
+      break;
+    case HE_PMTUD_STATE_SEARCH_COMPLETE:
+      switch(state) {
+        case HE_PMTUD_STATE_BASE:
+          // TODO: enter Base state if MAX_PROBES successive PLPMTUD-sized probes fail to be
+          // acknowledged
+          break;
+
+        default:
+          break;
+      }
+      break;
+  }
+
+  // State changed
+  conn->state = state;
+}
+
 void he_internal_pmtud_update(he_conn_t *conn) {
   if(conn == NULL || conn->pmtud_state == HE_PMTUD_STATE_DISABLED) {
     // Invalid state, do nothing

src/he/pmtud.h

@@ -26,6 +26,10 @@
 #ifndef PMTUD_H
 #define PMTUD_H
 
+/// The maximum value of the PROBE_COUNT counter. MAX_PROBES represents the limit for the number of
+/// consecutive probe attempts of any size.
+#define MAX_PROBES 3
+
 /// The smallest PMTU the discovery process will attempt to use
 #define MIN_PLPMTU 512
 
@@ -69,6 +73,11 @@ typedef enum he_pmtud_state {
 
 // Internal functions for PMTUD
 
+/**
+ * @brief Change PMTUD state
+ */
+void he_internal_change_pmtud_state(he_conn_t *conn, he_pmtud_state_t state);
+
 /**
  * @brief Update PMTUD state machine.
  */

test/he/test_conn.c

@@ -34,6 +34,7 @@
 // Internal Mocks
 #include "mock_fake_dispatch.h"
 #include "mock_wolf.h"
+#include "mock_pmtud.h"
 
 // External Mocks
 #include "mock_ssl.h"
@@ -1619,11 +1620,10 @@ void test_he_conn_get_curve_name(void) {
 
 void test_he_conn_start_pmtu_discovery(void) {
   conn.state = HE_STATE_ONLINE;
-  conn.event_cb = event_cb;
+
+  he_internal_change_pmtud_state_Expect(&conn, HE_PMTUD_STATE_BASE);
 
   TEST_ASSERT_EQUAL(HE_SUCCESS, he_conn_start_pmtu_discovery(&conn));
-  TEST_ASSERT_EQUAL(HE_PMTUD_STATE_BASE, conn.pmtud_state);
-  TEST_ASSERT_EQUAL(1, call_counter);
 }
 
 void test_he_conn_start_pmtu_discovery_null(void) {

test/he/test_conn_connect.c

@@ -38,6 +38,7 @@
 #include "mock_wolf.h"
 #include "mock_ssl_ctx.h"
 #include "mock_fake_dispatch.h"
+#include "mock_pmtud.h"
 
 // External Mocks
 #include "mock_ssl.h"