DTLS1.3: Fix missing retransmission due to failure to set timer.

DTLS 1.3 considers itself connected earlier than DTLS 1.2 did - when
second flight reaches the client. This CL fixes a bug that when
client is connected (state_ != SSL_CONNECTING), it would not
continue retransmitting. Continuous retransmission is needed
when the third flight is lost multiple times. Or really anytime that DTLS request it :)

This fixes the TODO in dtls_ice_integrationtest.cc in which dtls1.3
spuriously failed with certain (packet loss intensive) configurations.

CREDITS: sergeysu@ that found and fixed the problem!

Bug: chromium:441245658
Change-Id: I3302f6f384d7e4cda090184094a6fadaf7e4f129
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/406320
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Jonas Oreland <jonaso@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#45439}

p2p/dtls/dtls_ice_integrationtest.cc

diff --git a/p2p/dtls/dtls_ice_integrationtest.cc b/p2p/dtls/dtls_ice_integrationtest.cc
index c0011ca..b6b8d40 100644
--- a/p2p/dtls/dtls_ice_integrationtest.cc
+++ b/p2p/dtls/dtls_ice_integrationtest.cc
@@ -127,11 +127,7 @@
 
     BuiltInNetworkBehaviorConfig networkBehavior;
     networkBehavior.link_capacity = DataRate::KilobitsPerSec(220);
-    // TODO (webrtc:383141571) : Investigate why this testcase fails for
-    // DTLS 1.3 delay if networkBehavior.queue_delay_ms = 100ms.
-    // - unless both peers support dtls in stun, in which case it passes.
-    // - note: only for dtls1.3, it works for dtls1.2!
-    networkBehavior.queue_delay_ms = 50;
+    networkBehavior.queue_delay_ms = 100;
     networkBehavior.queue_length_packets = 30;
     networkBehavior.loss_percent = 50;
 

rtc_base/openssl_stream_adapter.cc

diff --git a/rtc_base/openssl_stream_adapter.cc b/rtc_base/openssl_stream_adapter.cc
index 4acbb55..2b45d37 100644
--- a/rtc_base/openssl_stream_adapter.cc
+++ b/rtc_base/openssl_stream_adapter.cc
@@ -852,10 +852,15 @@
           // We check the timer even after SSL_CONNECTED,
           // but ContinueSSL() is only needed when SSL_CONNECTING
           if (state_ == SSL_CONNECTING) {
+            // Note: timeout is set inside ContinueSSL()
             ContinueSSL();
+          } else if (state_ == SSL_CONNECTED) {
+            MaybeSetTimeout();
+          } else {
+            RTC_DCHECK_NOTREACHED() << "state_: " << state_;
           }
         } else {
-          RTC_DCHECK_NOTREACHED();
+          RTC_DCHECK_NOTREACHED() << "flag->alive() == false";
         }
         // This callback will never run again (stopped above).
         return TimeDelta::PlusInfinity();
@@ -970,6 +975,12 @@
     }
   }
 
+  MaybeSetTimeout();
+
+  return 0;
+}
+
+void OpenSSLStreamAdapter::MaybeSetTimeout() {
   if (ssl_ != nullptr) {
     struct timeval timeout;
     if (DTLSv1_get_timeout(ssl_, &timeout)) {
@@ -977,8 +988,6 @@
       SetTimeout(delay);
     }
   }
-
-  return 0;
 }
 
 void OpenSSLStreamAdapter::Error(absl::string_view context,

rtc_base/openssl_stream_adapter.h

diff --git a/rtc_base/openssl_stream_adapter.h b/rtc_base/openssl_stream_adapter.h
index 856d37c..c10e93e 100644
--- a/rtc_base/openssl_stream_adapter.h
+++ b/rtc_base/openssl_stream_adapter.h
@@ -210,6 +210,8 @@
            !peer_certificate_digest_value_.empty();
   }
 
+  void MaybeSetTimeout();
+
   const std::unique_ptr<StreamInterface> stream_;
   absl::AnyInvocable<void(SSLHandshakeError)> handshake_error_;