diff --git a/ChangeLog.d/dtls-cid-null.txt b/ChangeLog.d/dtls-cid-null.txt
new file mode 100644
index 0000000000..b0206164f3
--- /dev/null
+++ b/ChangeLog.d/dtls-cid-null.txt
@@ -0,0 +1,5 @@
+Bugfix
+   * In configurations with MBEDTLS_SSL_DTLS_CONNECTION_ID enabled but not
+     MBEDTLS_DEBUG_C, DTLS handshakes using CID would crash due to a null
+     pointer dereference. Fix this. Fixes #3998.
+     The fix was released, but not announced, in Mbed TLS 3.1.0.
diff --git a/configs/config-ccm-psk-dtls1_2.h b/configs/config-ccm-psk-dtls1_2.h
new file mode 100644
index 0000000000..183815deca
--- /dev/null
+++ b/configs/config-ccm-psk-dtls1_2.h
@@ -0,0 +1,108 @@
+/**
+ * \file config-ccm-psk-dtls1_2.h
+ *
+ * \brief Small configuration for DTLS 1.2 with PSK and AES-CCM ciphersuites
+ */
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+/*
+ * Minimal configuration for DTLS 1.2 with PSK and AES-CCM ciphersuites
+ *
+ * Distinguishing features:
+ * - Optimized for small code size, low bandwidth (on an unreliable transport),
+ *   and low RAM usage.
+ * - No asymmetric cryptography (no certificates, no Diffie-Hellman key
+ *   exchange).
+ * - Fully modern and secure (provided the pre-shared keys are generated and
+ *   stored securely).
+ * - Very low record overhead with CCM-8.
+ * - Includes several optional DTLS features typically used in IoT.
+ *
+ * See README.txt for usage instructions.
+ */
+
+/* System support */
+//#define MBEDTLS_HAVE_TIME /* Optionally used in Hello messages */
+/* Other MBEDTLS_HAVE_XXX flags irrelevant for this configuration */
+
+/* Mbed TLS modules */
+#define MBEDTLS_AES_C
+#define MBEDTLS_CCM_C
+#define MBEDTLS_CIPHER_C
+#define MBEDTLS_CTR_DRBG_C
+#define MBEDTLS_ENTROPY_C
+#define MBEDTLS_MD_C
+#define MBEDTLS_NET_C
+/* The library does not currently support enabling SHA-224 without SHA-256.
+ * A future version of the library will have this option disabled
+ * by default. */
+#define MBEDTLS_SHA224_C
+#define MBEDTLS_SHA256_C
+#define MBEDTLS_SSL_CLI_C
+#define MBEDTLS_SSL_COOKIE_C
+#define MBEDTLS_SSL_SRV_C
+#define MBEDTLS_SSL_TLS_C
+#define MBEDTLS_TIMING_C
+
+/* TLS protocol feature support */
+#define MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
+#define MBEDTLS_SSL_PROTO_TLS1_2
+#define MBEDTLS_SSL_PROTO_DTLS
+#define MBEDTLS_SSL_DTLS_ANTI_REPLAY
+#define MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE
+#define MBEDTLS_SSL_DTLS_CONNECTION_ID
+#define MBEDTLS_SSL_DTLS_HELLO_VERIFY
+#define MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
+
+/*
+ * Use only CCM_8 ciphersuites, and
+ * save ROM and a few bytes of RAM by specifying our own ciphersuite list
+ */
+#define MBEDTLS_SSL_CIPHERSUITES                        \
+        MBEDTLS_TLS_PSK_WITH_AES_256_CCM_8,             \
+        MBEDTLS_TLS_PSK_WITH_AES_128_CCM_8
+
+/*
+ * Save RAM at the expense of interoperability: do this only if you control
+ * both ends of the connection!  (See comments in "mbedtls/ssl.h".)
+ * The optimal size here depends on the typical size of records.
+ */
+#define MBEDTLS_SSL_IN_CONTENT_LEN              256
+#define MBEDTLS_SSL_OUT_CONTENT_LEN             256
+
+/* Save RAM at the expense of ROM */
+#define MBEDTLS_AES_ROM_TABLES
+
+/* Save some RAM by adjusting to your exact needs */
+#define MBEDTLS_PSK_MAX_LEN    16 /* 128-bits keys are generally enough */
+
+/*
+ * You should adjust this to the exact number of sources you're using: default
+ * is the "platform_entropy_poll" source, but you may want to add other ones
+ * Minimum is 2 for the entropy test suite.
+ */
+#define MBEDTLS_ENTROPY_MAX_SOURCES 2
+
+/* These defines are present so that the config modifying scripts can enable
+ * them during tests/scripts/test-ref-configs.pl */
+//#define MBEDTLS_USE_PSA_CRYPTO
+//#define MBEDTLS_PSA_CRYPTO_C
+
+/* Error messages and TLS debugging traces
+ * (huge code size increase, needed for tests/ssl-opt.sh) */
+//#define MBEDTLS_DEBUG_C
+//#define MBEDTLS_ERROR_C
diff --git a/configs/config-ccm-psk-tls1_2.h b/configs/config-ccm-psk-tls1_2.h
index 475883702e..f935a33f25 100644
--- a/configs/config-ccm-psk-tls1_2.h
+++ b/configs/config-ccm-psk-tls1_2.h
@@ -21,11 +21,15 @@
  */
 /*
  * Minimal configuration for TLS 1.2 with PSK and AES-CCM ciphersuites
+ *
  * Distinguishing features:
- * - no bignum, no PK, no X509
- * - fully modern and secure (provided the pre-shared keys have high entropy)
- * - very low record overhead with CCM-8
- * - optimized for low RAM usage
+ * - Optimized for small code size, low bandwidth (on a reliable transport),
+ *   and low RAM usage.
+ * - No asymmetric cryptography (no certificates, no Diffie-Hellman key
+ *   exchange).
+ * - Fully modern and secure (provided the pre-shared keys are generated and
+ *   stored securely).
+ * - Very low record overhead with CCM-8.
  *
  * See README.txt for usage instructions.
  */
@@ -34,11 +38,7 @@
 //#define MBEDTLS_HAVE_TIME /* Optionally used in Hello messages */
 /* Other MBEDTLS_HAVE_XXX flags irrelevant for this configuration */
 
-/* mbed TLS feature support */
-#define MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
-#define MBEDTLS_SSL_PROTO_TLS1_2
-
-/* mbed TLS modules */
+/* Mbed TLS modules */
 #define MBEDTLS_AES_C
 #define MBEDTLS_CCM_C
 #define MBEDTLS_CIPHER_C
@@ -55,18 +55,9 @@
 #define MBEDTLS_SSL_SRV_C
 #define MBEDTLS_SSL_TLS_C
 
-/* Save RAM at the expense of ROM */
-#define MBEDTLS_AES_ROM_TABLES
-
-/* Save some RAM by adjusting to your exact needs */
-#define MBEDTLS_PSK_MAX_LEN    16 /* 128-bits keys are generally enough */
-
-/*
- * You should adjust this to the exact number of sources you're using: default
- * is the "platform_entropy_poll" source, but you may want to add other ones
- * Minimum is 2 for the entropy test suite.
- */
-#define MBEDTLS_ENTROPY_MAX_SOURCES 2
+/* TLS protocol feature support */
+#define MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
+#define MBEDTLS_SSL_PROTO_TLS1_2
 
 /*
  * Use only CCM_8 ciphersuites, and
@@ -81,10 +72,28 @@
  * both ends of the connection!  (See comments in "mbedtls/ssl.h".)
  * The optimal size here depends on the typical size of records.
  */
-#define MBEDTLS_SSL_IN_CONTENT_LEN             1024
+#define MBEDTLS_SSL_IN_CONTENT_LEN              1024
 #define MBEDTLS_SSL_OUT_CONTENT_LEN             1024
 
+/* Save RAM at the expense of ROM */
+#define MBEDTLS_AES_ROM_TABLES
+
+/* Save some RAM by adjusting to your exact needs */
+#define MBEDTLS_PSK_MAX_LEN    16 /* 128-bits keys are generally enough */
+
+/*
+ * You should adjust this to the exact number of sources you're using: default
+ * is the "platform_entropy_poll" source, but you may want to add other ones
+ * Minimum is 2 for the entropy test suite.
+ */
+#define MBEDTLS_ENTROPY_MAX_SOURCES 2
+
 /* These defines are present so that the config modifying scripts can enable
  * them during tests/scripts/test-ref-configs.pl */
 //#define MBEDTLS_USE_PSA_CRYPTO
 //#define MBEDTLS_PSA_CRYPTO_C
+
+/* Error messages and TLS debugging traces
+ * (huge code size increase, needed for tests/ssl-opt.sh) */
+//#define MBEDTLS_DEBUG_C
+//#define MBEDTLS_ERROR_C
diff --git a/configs/config-suite-b.h b/configs/config-suite-b.h
index 95c40875f7..68ccf10cf1 100644
--- a/configs/config-suite-b.h
+++ b/configs/config-suite-b.h
@@ -115,3 +115,8 @@
  * them during tests/scripts/test-ref-configs.pl */
 //#define MBEDTLS_USE_PSA_CRYPTO
 //#define MBEDTLS_PSA_CRYPTO_C
+
+/* Error messages and TLS debugging traces
+ * (huge code size increase, needed for tests/ssl-opt.sh) */
+//#define MBEDTLS_DEBUG_C
+//#define MBEDTLS_ERROR_C
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 948d2e016e..b0213f0270 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -169,9 +169,6 @@ int main( void )
 
 /*
  * Size of the basic I/O buffer. Able to hold our default response.
- *
- * You will need to adapt the mbedtls_ssl_get_bytes_avail() test in ssl-opt.sh
- * if you change this value to something outside the range <= 100 or > 500
  */
 #define DFL_IO_BUF_LEN      200
 
@@ -2113,10 +2110,26 @@ int main( int argc, char *argv[] )
 #if defined(MBEDTLS_DEBUG_C)
     mbedtls_debug_set_threshold( opt.debug_level );
 #endif
-    buf = mbedtls_calloc( 1, opt.buffer_size + 1 );
+
+    /* buf will alternatively contain the input read from the client and the
+     * response that's about to be sent, plus a null byte in each case. */
+    size_t buf_content_size = opt.buffer_size;
+    /* The default response contains the ciphersuite name. Leave enough
+     * room for that plus some margin. */
+    if( buf_content_size < strlen( HTTP_RESPONSE ) + 80 )
+    {
+        buf_content_size = strlen( HTTP_RESPONSE ) + 80;
+    }
+    if( opt.response_size != DFL_RESPONSE_SIZE &&
+        buf_content_size < (size_t) opt.response_size )
+    {
+        buf_content_size = opt.response_size;
+    }
+    buf = mbedtls_calloc( 1, buf_content_size + 1 );
     if( buf == NULL )
     {
-        mbedtls_printf( "Could not allocate %u bytes\n", opt.buffer_size );
+        mbedtls_printf( "Could not allocate %lu bytes\n",
+                        (unsigned long) buf_content_size + 1 );
         ret = 3;
         goto exit;
     }
@@ -3550,7 +3563,7 @@ data_exchange:
         do
         {
             int terminated = 0;
-            len = opt.buffer_size - 1;
+            len = opt.buffer_size;
             memset( buf, 0, opt.buffer_size );
             ret = mbedtls_ssl_read( &ssl, buf, len );
 
@@ -3651,7 +3664,7 @@ data_exchange:
     }
     else /* Not stream, so datagram */
     {
-        len = opt.buffer_size - 1;
+        len = opt.buffer_size;
         memset( buf, 0, opt.buffer_size );
 
         do
@@ -3753,6 +3766,8 @@ data_exchange:
     mbedtls_printf( "  > Write to client:" );
     fflush( stdout );
 
+    /* If the format of the response changes, make sure there is enough
+     * room in buf (buf_content_size calculation above). */
     len = sprintf( (char *) buf, HTTP_RESPONSE,
                    mbedtls_ssl_get_ciphersuite( &ssl ) );
 
diff --git a/programs/test/dlopen.c b/programs/test/dlopen.c
index 3b88df4cf3..c0836046a3 100644
--- a/programs/test/dlopen.c
+++ b/programs/test/dlopen.c
@@ -19,8 +19,9 @@
 
 #include "mbedtls/build_info.h"
 
+#if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
-#if !defined(MBEDTLS_PLATFORM_C)
+#else
 #include <stdio.h>
 #include <stdlib.h>
 #define mbedtls_fprintf    fprintf
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 55806fd3ac..8528a4f013 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -2326,18 +2326,6 @@ component_test_variable_ssl_in_out_buffer_len_CID () {
     tests/compat.sh
 }
 
-component_test_CID_no_debug() {
-    msg "build: Connection ID enabled, debug disabled"
-    scripts/config.py unset MBEDTLS_DEBUG_C
-    scripts/config.py set MBEDTLS_SSL_DTLS_CONNECTION_ID
-
-    CC=gcc cmake .
-    make
-
-    msg "test: Connection ID enabled, debug disabled"
-    make test
-}
-
 component_test_ssl_alloc_buffer_and_mfl () {
     msg "build: default config with memory buffer allocator and MFL extension"
     scripts/config.py set MBEDTLS_MEMORY_BUFFER_ALLOC_C
@@ -2978,16 +2966,17 @@ component_test_cmake_out_of_source () {
 
     msg "test: cmake 'out-of-source' build"
     make test
-    # Test an SSL option that requires an auxiliary script in test/scripts/.
+    # Check that ssl-opt.sh can find the test programs.
     # Also ensure that there are no error messages such as
     # "No such file or directory", which would indicate that some required
     # file is missing (ssl-opt.sh tolerates the absence of some files so
     # may exit with status 0 but emit errors).
-    ./tests/ssl-opt.sh -f 'Fallback SCSV: beginning of list' 2>ssl-opt.err
+    ./tests/ssl-opt.sh -f 'Default' >ssl-opt.out 2>ssl-opt.err
+    grep PASS ssl-opt.out
     cat ssl-opt.err >&2
     # If ssl-opt.err is non-empty, record an error and keep going.
     [ ! -s ssl-opt.err ]
-    rm ssl-opt.err
+    rm ssl-opt.out ssl-opt.err
     cd "$MBEDTLS_ROOT_DIR"
     rm -rf "$OUT_OF_SOURCE_DIR"
 }
diff --git a/tests/scripts/test-ref-configs.pl b/tests/scripts/test-ref-configs.pl
index dc0f120e44..15209b4a0d 100755
--- a/tests/scripts/test-ref-configs.pl
+++ b/tests/scripts/test-ref-configs.pl
@@ -32,11 +32,19 @@ my %configs = (
         'compat' => '-m tls12 -f \'^TLS-PSK-WITH-AES-...-CCM-8\'',
         'test_again_with_use_psa' => 1
     },
+    'config-ccm-psk-dtls1_2.h' => {
+        'compat' => '-m dtls12 -f \'^TLS-PSK-WITH-AES-...-CCM-8\'',
+        'opt' => ' ',
+        'opt_needs_debug' => 1,
+        'test_again_with_use_psa' => 1
+    },
     'config-no-entropy.h' => {
     },
     'config-suite-b.h' => {
         'compat' => "-m tls12 -f 'ECDHE-ECDSA.*AES.*GCM' -p mbedTLS",
         'test_again_with_use_psa' => 1,
+        'opt' => ' ',
+        'opt_needs_debug' => 1,
     },
     'config-symmetric-only.h' => {
         'test_again_with_use_psa' => 0, # Uses PSA by default, no need to test it twice
@@ -49,17 +57,14 @@ my %configs = (
 
 # If no config-name is provided, use all known configs.
 # Otherwise, use the provided names only.
+my @configs_to_test = sort keys %configs;
 if ($#ARGV >= 0) {
-    my %configs_ori = ( %configs );
-    %configs = ();
-
-    foreach my $conf_name (@ARGV) {
-        if( ! exists $configs_ori{$conf_name} ) {
+    foreach my $conf_name ( @ARGV ) {
+        if( ! exists $configs{$conf_name} ) {
             die "Unknown configuration: $conf_name\n";
-        } else {
-            $configs{$conf_name} = $configs_ori{$conf_name};
         }
     }
+    @configs_to_test = @ARGV;
 }
 
 -d 'library' && -d 'include' && -d 'tests' or die "Must be run from root\n";
@@ -84,25 +89,27 @@ if (!-e "tests/seedfile" || -s "tests/seedfile" < 64) {
 }
 
 sub perform_test {
-    my $conf = $_[0];
+    my $conf_file = $_[0];
     my $data = $_[1];
     my $test_with_psa = $_[2];
 
+    my $conf_name = $conf_file;
+    if ( $test_with_psa )
+    {
+        $conf_name .= "+PSA";
+    }
+
     system( "cp $config_h.bak $config_h" ) and die;
     system( "make clean" ) and die;
 
     print "\n******************************************\n";
-    print "* Testing configuration: $conf\n";
-    if ( $test_with_psa )
-    {
-        print "* ENABLING MBEDTLS_PSA_CRYPTO_C and MBEDTLS_USE_PSA_CRYPTO \n";
-    }
+    print "* Testing configuration: $conf_name\n";
     print "******************************************\n";
 
-    $ENV{MBEDTLS_TEST_CONFIGURATION} = $conf;
+    $ENV{MBEDTLS_TEST_CONFIGURATION} = $conf_name;
 
-    system( "cp configs/$conf $config_h" )
-        and abort "Failed to activate $conf\n";
+    system( "cp configs/$conf_file $config_h" )
+        and abort "Failed to activate $conf_file\n";
 
     if ( $test_with_psa )
     {
@@ -110,41 +117,52 @@ sub perform_test {
         system( "scripts/config.py set MBEDTLS_USE_PSA_CRYPTO" );
     }
 
-    system( "CFLAGS='-Os -Werror -Wall -Wextra' make" ) and abort "Failed to build: $conf\n";
-    system( "make test" ) and abort "Failed test suite: $conf\n";
+    system( "CFLAGS='-Os -Werror -Wall -Wextra' make" ) and abort "Failed to build: $conf_name\n";
+    system( "make test" ) and abort "Failed test suite: $conf_name\n";
 
     my $compat = $data->{'compat'};
     if( $compat )
     {
-        print "\nrunning compat.sh $compat\n";
+        print "\nrunning compat.sh $compat ($conf_name)\n";
         system( "tests/compat.sh $compat" )
-            and abort "Failed compat.sh: $conf\n";
+            and abort "Failed compat.sh: $conf_name\n";
     }
     else
     {
-        print "\nskipping compat.sh\n";
+        print "\nskipping compat.sh ($conf_name)\n";
     }
 
     my $opt = $data->{'opt'};
     if( $opt )
     {
-        print "\nrunning ssl-opt.sh $opt\n";
+        if( $data->{'opt_needs_debug'} )
+        {
+            print "\nrebuilding with debug traces for ssl-opt ($conf_name)\n";
+            $conf_name .= '+DEBUG';
+            $ENV{MBEDTLS_TEST_CONFIGURATION} = $conf_name;
+            system( "make clean" );
+            system( "scripts/config.py set MBEDTLS_DEBUG_C" );
+            system( "scripts/config.py set MBEDTLS_ERROR_C" );
+            system( "CFLAGS='-Os -Werror -Wall -Wextra' make" ) and abort "Failed to build: $conf_name\n";
+        }
+
+        print "\nrunning ssl-opt.sh $opt ($conf_name)\n";
         system( "tests/ssl-opt.sh $opt" )
-            and abort "Failed ssl-opt.sh: $conf\n";
+            and abort "Failed ssl-opt.sh: $conf_name\n";
     }
     else
     {
-        print "\nskipping ssl-opt.sh\n";
+        print "\nskipping ssl-opt.sh ($conf_name)\n";
     }
 }
 
-while( my ($conf, $data) = each %configs ) {
-    my $test_with_psa = $data->{'test_again_with_use_psa'};
+foreach my $conf ( @configs_to_test ) {
+    my $test_with_psa = $configs{$conf}{'test_again_with_use_psa'};
     if ( $test_with_psa )
     {
-        perform_test( $conf, $data, $test_with_psa );
+        perform_test( $conf, $configs{$conf}, $test_with_psa );
     }
-    perform_test( $conf, $data, 0 );
+    perform_test( $conf, $configs{$conf}, 0 );
 }
 
 system( "mv $config_h.bak $config_h" ) and warn "$config_h not restored\n";
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 6693c5f206..aa4604546e 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -263,6 +263,19 @@ requires_config_value_equals() {
     fi
 }
 
+# Require Mbed TLS to support the given protocol version.
+#
+# Inputs:
+# * $1: protocol version in mbedtls syntax (argument to force_version=)
+requires_protocol_version() {
+    # Support for DTLS is detected separately in detect_dtls().
+    case "$1" in
+        tls12|dtls12) requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2;;
+        tls13|dtls13) requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3;;
+        *) echo "Unknown required protocol version: $1"; exit 1;;
+    esac
+}
+
 # Space-separated list of ciphersuites supported by this build of
 # Mbed TLS.
 P_CIPHERSUITES=" $($P_CLI --help 2>/dev/null |
@@ -275,24 +288,105 @@ requires_ciphersuite_enabled() {
     esac
 }
 
-# maybe_requires_ciphersuite_enabled CMD [RUN_TEST_OPTION...]
-# If CMD (call to a TLS client or server program) requires a specific
-# ciphersuite, arrange to only run the test case if this ciphersuite is
-# enabled.
-maybe_requires_ciphersuite_enabled() {
+# detect_required_features CMD [RUN_TEST_OPTION...]
+# If CMD (call to a TLS client or server program) requires certain features,
+# arrange to only run the following test case if those features are enabled.
+detect_required_features() {
     case "$1" in
-        *\ force_ciphersuite=*) :;;
-        *) return;; # No specific required ciphersuite
+        *\ force_version=*)
+            tmp="${1##*\ force_version=}"
+            tmp="${tmp%%[!-0-9A-Z_a-z]*}"
+            requires_protocol_version "$tmp";;
     esac
-    ciphersuite="${1##*\ force_ciphersuite=}"
-    ciphersuite="${ciphersuite%%[!-0-9A-Z_a-z]*}"
-    shift
 
-    requires_ciphersuite_enabled "$ciphersuite"
+    case "$1" in
+        *\ force_ciphersuite=*)
+            tmp="${1##*\ force_ciphersuite=}"
+            tmp="${tmp%%[!-0-9A-Z_a-z]*}"
+            requires_ciphersuite_enabled "$tmp";;
+    esac
 
-    unset ciphersuite
+    case " $1 " in
+        *[-_\ =]tickets=[^0]*)
+            requires_config_enabled MBEDTLS_SSL_TICKET_C;;
+    esac
+    case " $1 " in
+        *[-_\ =]alpn=*)
+            requires_config_enabled MBEDTLS_SSL_ALPN;;
+    esac
+
+    unset tmp
 }
 
+requires_certificate_authentication () {
+    if [ "$PSK_ONLY" = "YES" ]; then
+        SKIP_NEXT="YES"
+    fi
+}
+
+adapt_cmd_for_psk () {
+    case "$2" in
+        *openssl*) s='-psk abc123 -nocert';;
+        *gnutls-*) s='--pskkey=abc123';;
+        *) s='psk=abc123';;
+    esac
+    eval $1='"$2 $s"'
+    unset s
+}
+
+# maybe_adapt_for_psk [RUN_TEST_OPTION...]
+# If running in a PSK-only build, maybe adapt the test to use a pre-shared key.
+#
+# If not running in a PSK-only build, do nothing.
+# If the test looks like it doesn't use a pre-shared key but can run with a
+# pre-shared key, pass a pre-shared key. If the test looks like it can't run
+# with a pre-shared key, skip it. If the test looks like it's already using
+# a pre-shared key, do nothing.
+#
+# This code does not consider builds with ECDHE-PSK or RSA-PSK.
+#
+# Inputs:
+# * $CLI_CMD, $SRV_CMD, $PXY_CMD: client/server/proxy commands.
+# * $PSK_ONLY: YES if running in a PSK-only build (no asymmetric key exchanges).
+# * "$@": options passed to run_test.
+#
+# Outputs:
+# * $CLI_CMD, $SRV_CMD: may be modified to add PSK-relevant arguments.
+# * $SKIP_NEXT: set to YES if the test can't run with PSK.
+maybe_adapt_for_psk() {
+    if [ "$PSK_ONLY" != "YES" ]; then
+        return
+    fi
+    if [ "$SKIP_NEXT" = "YES" ]; then
+        return
+    fi
+    case "$CLI_CMD $SRV_CMD" in
+        *[-_\ =]psk*|*[-_\ =]PSK*)
+            return;;
+        *force_ciphersuite*)
+            # The test case forces a non-PSK cipher suite. In some cases, a
+            # PSK cipher suite could be substituted, but we're not ready for
+            # that yet.
+            SKIP_NEXT="YES"
+            return;;
+        *\ auth_mode=*|*[-_\ =]crt[_=]*)
+            # The test case involves certificates. PSK won't do.
+            SKIP_NEXT="YES"
+            return;;
+    esac
+    adapt_cmd_for_psk CLI_CMD "$CLI_CMD"
+    adapt_cmd_for_psk SRV_CMD "$SRV_CMD"
+}
+
+case " $CONFIGS_ENABLED " in
+    *\ MBEDTLS_KEY_EXCHANGE_[^P]*) PSK_ONLY="NO";;
+    *\ MBEDTLS_KEY_EXCHANGE_P[^S]*) PSK_ONLY="NO";;
+    *\ MBEDTLS_KEY_EXCHANGE_PS[^K]*) PSK_ONLY="NO";;
+    *\ MBEDTLS_KEY_EXCHANGE_PSK[^_]*) PSK_ONLY="NO";;
+    *\ MBEDTLS_KEY_EXCHANGE_PSK_ENABLED\ *) PSK_ONLY="YES";;
+    *) PSK_ONLY="NO";;
+esac
+
 # skip next test if OpenSSL doesn't support FALLBACK_SCSV
 requires_openssl_with_fallback_scsv() {
     if [ -z "${OPENSSL_HAS_FBSCSV:-}" ]; then
@@ -666,13 +760,11 @@ if type lsof >/dev/null 2>/dev/null; then
         fi
         # Make a tight loop, server normally takes less than 1s to start.
         while true; do
-              SERVER_PIDS=$(lsof -a -n -b -i "$proto:$1" -F p)
+              SERVER_PIDS=$(lsof -a -n -b -i "$proto:$1" -t)
               # When we use a proxy, it will be listening on the same port we
               # are checking for as well as the server and lsof will list both.
-              # If multiple PIDs are returned, each one will be on a separate
-              # line, each prepended with 'p'.
              case ${newline}${SERVER_PIDS}${newline} in
-                  *${newline}p${2}${newline}*) break;;
+                  *${newline}${2}${newline}*) break;;
               esac
               if [ $(( $(date +%s) - $START_TIME )) -gt $DOG_DELAY ]; then
                   echo "$3 START TIMEOUT"
@@ -813,6 +905,39 @@ is_gnutls() {
     esac
 }
 
+# Determine what calc_verify trace is to be expected, if any.
+#
+# calc_verify is only called for two things: to calculate the
+# extended master secret, and to process client authentication.
+#
+# Warning: the current implementation assumes that extended_ms is not
+#          disabled on the client or on the server.
+#
+# Inputs:
+# * $1: the value of the server auth_mode parameter.
+#       'required' if client authentication is expected,
+#       'none' or absent if not.
+# * $CONFIGS_ENABLED
+#
+# Outputs:
+# * $maybe_calc_verify: set to a trace expected in the debug logs
+set_maybe_calc_verify() {
+    maybe_calc_verify=
+    case $CONFIGS_ENABLED in
+        *\ MBEDTLS_SSL_EXTENDED_MASTER_SECRET\ *) :;;
+        *)
+            case ${1-} in
+                ''|none) return;;
+                required) :;;
+                *) echo "Bad parameter 1 to set_maybe_calc_verify: $1"; exit 1;;
+            esac
+    esac
+    case $CONFIGS_ENABLED in
+        *\ MBEDTLS_USE_PSA_CRYPTO\ *) maybe_calc_verify="PSA calc verify";;
+        *) maybe_calc_verify="<= calc verify";;
+    esac
+}
+
 # Compare file content
 # Usage: find_in_both pattern file1 file2
 # extract from file1 the first line matching the pattern
@@ -839,11 +964,15 @@ skip_handshake_stage_check() {
 #
 # Analyze and possibly instrument $PXY_CMD, $CLI_CMD, $SRV_CMD to pass
 # extra arguments or go through wrappers.
-# Set $DTLS (0=TLS, 1=DTLS).
+#
+# Inputs:
+# * $@: supplemental options to run_test() (after the mandatory arguments).
+# * $CLI_CMD, $PXY_CMD, $SRV_CMD: the client, proxy and server commands.
+# * $DTLS: 1 if DTLS, otherwise 0.
+#
+# Outputs:
+# * $CLI_CMD, $PXY_CMD, $SRV_CMD: may be tweaked.
 analyze_test_commands() {
-    # update DTLS variable
-    detect_dtls "$SRV_CMD"
-
     # if the test uses DTLS but no custom proxy, add a simple proxy
     # as it provides timing info that's useful to debug failures
     if [ -z "$PXY_CMD" ] && [ "$DTLS" -eq 1 ]; then
@@ -1150,9 +1279,19 @@ run_test() {
             requires_config_enabled MBEDTLS_FS_IO;;
     esac
 
-    # If the client or serve requires a ciphersuite, check that it's enabled.
-    maybe_requires_ciphersuite_enabled "$SRV_CMD" "$@"
-    maybe_requires_ciphersuite_enabled "$CLI_CMD" "$@"
+    # Check if the test uses DTLS.
+    detect_dtls "$SRV_CMD"
+    if [ "$DTLS" -eq 1 ]; then
+        requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
+    fi
+
+    # If the client or server requires certain features that can be detected
+    # from their command-line arguments, check that they're enabled.
+    detect_required_features "$SRV_CMD" "$@"
+    detect_required_features "$CLI_CMD" "$@"
+
+    # If we're in a PSK-only build and the test can be adapted to PSK, do that.
+    maybe_adapt_for_psk "$@"
 
     # should we skip?
     if [ "X$SKIP_NEXT" = "XYES" ]; then
@@ -1193,43 +1332,41 @@ run_test() {
 }
 
 run_test_psa() {
-    requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
     requires_config_enabled MBEDTLS_USE_PSA_CRYPTO
+    set_maybe_calc_verify none
     run_test    "PSA-supported ciphersuite: $1" \
                 "$P_SRV debug_level=3 force_version=tls12" \
                 "$P_CLI debug_level=3 force_ciphersuite=$1" \
                 0 \
-                -c "PSA calc verify" \
+                -c "$maybe_calc_verify" \
                 -c "calc PSA finished" \
-                -s "PSA calc verify" \
+                -s "$maybe_calc_verify" \
                 -s "calc PSA finished" \
-                -C "Failed to setup PSA-based cipher context"\
-                -S "Failed to setup PSA-based cipher context"\
                 -s "Protocol is TLSv1.2" \
                 -c "Perform PSA-based ECDH computation."\
                 -c "Perform PSA-based computation of digest of ServerKeyExchange" \
                 -S "error" \
                 -C "error"
+    unset maybe_calc_verify
 }
 
 run_test_psa_force_curve() {
-    requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
     requires_config_enabled MBEDTLS_USE_PSA_CRYPTO
+    set_maybe_calc_verify none
     run_test    "PSA - ECDH with $1" \
                 "$P_SRV debug_level=4 force_version=tls12 curves=$1" \
                 "$P_CLI debug_level=4 force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-128-GCM-SHA256 curves=$1" \
                 0 \
-                -c "PSA calc verify" \
+                -c "$maybe_calc_verify" \
                 -c "calc PSA finished" \
-                -s "PSA calc verify" \
+                -s "$maybe_calc_verify" \
                 -s "calc PSA finished" \
-                -C "Failed to setup PSA-based cipher context"\
-                -S "Failed to setup PSA-based cipher context"\
                 -s "Protocol is TLSv1.2" \
                 -c "Perform PSA-based ECDH computation."\
                 -c "Perform PSA-based computation of digest of ServerKeyExchange" \
                 -S "error" \
                 -C "error"
+    unset maybe_calc_verify
 }
 
 # Test that the server's memory usage after a handshake is reduced when a client specifies
@@ -1447,8 +1584,10 @@ trap cleanup INT TERM HUP
 # Checks that:
 # - things work with all ciphersuites active (used with config-full in all.sh)
 # - the expected parameters are selected
-#   ("signature_algorithm ext: 6" means SHA-512 (highest common hash))
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_ciphersuite_enabled TLS-ECDHE-RSA-WITH-CHACHA20-POLY1305-SHA256
+requires_config_enabled MBEDTLS_SHA512_C # "signature_algorithm ext: 6"
+requires_config_enabled MBEDTLS_ECP_DP_CURVE25519_ENABLED
 run_test    "Default" \
             "$P_SRV debug_level=3" \
             "$P_CLI" \
@@ -1461,6 +1600,7 @@ run_test    "Default" \
             -C "error"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_ciphersuite_enabled TLS-ECDHE-RSA-WITH-CHACHA20-POLY1305-SHA256
 run_test    "Default, DTLS" \
             "$P_SRV dtls=1" \
             "$P_CLI dtls=1" \
@@ -2734,6 +2874,7 @@ run_test    "Encrypt then MAC: client disabled, server enabled" \
 # Tests for Extended Master Secret extension
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_EXTENDED_MASTER_SECRET
 run_test    "Extended Master Secret: default" \
             "$P_SRV debug_level=3" \
             "$P_CLI debug_level=3" \
@@ -2746,6 +2887,7 @@ run_test    "Extended Master Secret: default" \
             -s "session hash for extended master secret"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_EXTENDED_MASTER_SECRET
 run_test    "Extended Master Secret: client enabled, server disabled" \
             "$P_SRV debug_level=3 extended_ms=0" \
             "$P_CLI debug_level=3 extended_ms=1" \
@@ -2758,6 +2900,7 @@ run_test    "Extended Master Secret: client enabled, server disabled" \
             -S "session hash for extended master secret"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_EXTENDED_MASTER_SECRET
 run_test    "Extended Master Secret: client disabled, server enabled" \
             "$P_SRV debug_level=3 extended_ms=1" \
             "$P_CLI debug_level=3 extended_ms=0" \
@@ -2807,7 +2950,6 @@ run_test    "Encrypt then MAC, DTLS: disabled, empty application data record" \
 
 # Tests for CBC 1/n-1 record splitting
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "CBC Record splitting: TLS 1.2, no splitting" \
             "$P_SRV force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
@@ -3233,6 +3375,7 @@ run_test    "Session resume using tickets, DTLS: openssl client" \
 # Tests for Session Resume based on session-ID and cache
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: tickets enabled on client" \
             "$P_SRV debug_level=3 tickets=0" \
             "$P_CLI debug_level=3 tickets=1 reconnect=1" \
@@ -3248,6 +3391,7 @@ run_test    "Session resume using cache: tickets enabled on client" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: tickets enabled on server" \
             "$P_SRV debug_level=3 tickets=1" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -3263,6 +3407,7 @@ run_test    "Session resume using cache: tickets enabled on server" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: cache_max=0" \
             "$P_SRV debug_level=3 tickets=0 cache_max=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -3273,6 +3418,7 @@ run_test    "Session resume using cache: cache_max=0" \
             -C "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: cache_max=1" \
             "$P_SRV debug_level=3 tickets=0 cache_max=1" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -3283,6 +3429,7 @@ run_test    "Session resume using cache: cache_max=1" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: timeout > delay" \
             "$P_SRV debug_level=3 tickets=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_delay=0" \
@@ -3293,6 +3440,7 @@ run_test    "Session resume using cache: timeout > delay" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: timeout < delay" \
             "$P_SRV debug_level=3 tickets=0 cache_timeout=1" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_delay=2" \
@@ -3303,6 +3451,7 @@ run_test    "Session resume using cache: timeout < delay" \
             -C "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: no timeout" \
             "$P_SRV debug_level=3 tickets=0 cache_timeout=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_delay=2" \
@@ -3313,6 +3462,7 @@ run_test    "Session resume using cache: no timeout" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: session copy" \
             "$P_SRV debug_level=3 tickets=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_mode=0" \
@@ -3323,6 +3473,7 @@ run_test    "Session resume using cache: session copy" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: openssl client" \
             "$P_SRV debug_level=3 tickets=0" \
             "( $O_CLI -sess_out $SESSION; \
@@ -3336,6 +3487,7 @@ run_test    "Session resume using cache: openssl client" \
             -s "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache: openssl server" \
             "$O_SRV -tls1_2" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -3347,6 +3499,7 @@ run_test    "Session resume using cache: openssl server" \
 # Tests for Session Resume based on session-ID and cache, DTLS
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: tickets enabled on client" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=1 reconnect=1 skip_close_notify=1" \
@@ -3362,6 +3515,7 @@ run_test    "Session resume using cache, DTLS: tickets enabled on client" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: tickets enabled on server" \
             "$P_SRV dtls=1 debug_level=3 tickets=1" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 skip_close_notify=1" \
@@ -3377,6 +3531,7 @@ run_test    "Session resume using cache, DTLS: tickets enabled on server" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: cache_max=0" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_max=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 skip_close_notify=1" \
@@ -3387,6 +3542,7 @@ run_test    "Session resume using cache, DTLS: cache_max=0" \
             -C "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: cache_max=1" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_max=1" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 skip_close_notify=1" \
@@ -3397,6 +3553,7 @@ run_test    "Session resume using cache, DTLS: cache_max=1" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: timeout > delay" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 skip_close_notify=1 reco_delay=0" \
@@ -3407,6 +3564,7 @@ run_test    "Session resume using cache, DTLS: timeout > delay" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: timeout < delay" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_timeout=1" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 skip_close_notify=1 reco_delay=2" \
@@ -3417,6 +3575,7 @@ run_test    "Session resume using cache, DTLS: timeout < delay" \
             -C "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: no timeout" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_timeout=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 skip_close_notify=1 reco_delay=2" \
@@ -3427,6 +3586,7 @@ run_test    "Session resume using cache, DTLS: no timeout" \
             -c "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: session copy" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 skip_close_notify=1 reco_mode=0" \
@@ -3440,6 +3600,7 @@ run_test    "Session resume using cache, DTLS: session copy" \
 # probability with OpenSSL 1.0.2g on the CI, see #5012.
 requires_openssl_next
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: openssl client" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "( $O_NEXT_CLI -dtls -sess_out $SESSION; \
@@ -3453,6 +3614,7 @@ run_test    "Session resume using cache, DTLS: openssl client" \
             -s "a session has been resumed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "Session resume using cache, DTLS: openssl server" \
             "$O_SRV -dtls" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1" \
@@ -5038,7 +5200,6 @@ run_test    "Authentication, CA callback: client max_int chain, server required"
 # Tests for certificate selection based on SHA verson
 
 requires_config_disabled MBEDTLS_X509_REMOVE_INFO
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Certificate hash: client TLS 1.2 -> SHA-2" \
             "$P_SRV force_version=tls12 crt_file=data_files/server5.crt \
                     key_file=data_files/server5.key \
@@ -6536,23 +6697,38 @@ run_test    "ClientHello without extensions" \
 
 # Tests for mbedtls_ssl_get_bytes_avail()
 
+# The server first reads buffer_size-1 bytes, then reads the remainder.
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "mbedtls_ssl_get_bytes_avail: no extra data" \
-            "$P_SRV" \
+            "$P_SRV buffer_size=100" \
             "$P_CLI request_size=100" \
             0 \
             -s "Read from client: 100 bytes read$"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "mbedtls_ssl_get_bytes_avail: extra data" \
-            "$P_SRV" \
-            "$P_CLI request_size=500" \
+run_test    "mbedtls_ssl_get_bytes_avail: extra data (+1)" \
+            "$P_SRV buffer_size=100" \
+            "$P_CLI request_size=101" \
             0 \
-            -s "Read from client: 500 bytes read (.*+.*)"
+            -s "Read from client: 101 bytes read (100 + 1)"
+
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_max_content_len 200
+run_test    "mbedtls_ssl_get_bytes_avail: extra data (*2)" \
+            "$P_SRV buffer_size=100" \
+            "$P_CLI request_size=200" \
+            0 \
+            -s "Read from client: 200 bytes read (100 + 100)"
+
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+run_test    "mbedtls_ssl_get_bytes_avail: extra data (max)" \
+            "$P_SRV buffer_size=100" \
+            "$P_CLI request_size=$MAX_CONTENT_LEN" \
+            0 \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read (100 + $((MAX_CONTENT_LEN - 100)))"
 
 # Tests for small client packets
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small client packet TLS 1.2 BlockCipher" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=1 \
@@ -6560,7 +6736,6 @@ run_test    "Small client packet TLS 1.2 BlockCipher" \
             0 \
             -s "Read from client: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small client packet TLS 1.2 BlockCipher, without EtM" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=1 \
@@ -6568,7 +6743,6 @@ run_test    "Small client packet TLS 1.2 BlockCipher, without EtM" \
             0 \
             -s "Read from client: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small client packet TLS 1.2 BlockCipher larger MAC" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=1 \
@@ -6576,7 +6750,6 @@ run_test    "Small client packet TLS 1.2 BlockCipher larger MAC" \
             0 \
             -s "Read from client: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small client packet TLS 1.2 AEAD" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=1 \
@@ -6584,7 +6757,6 @@ run_test    "Small client packet TLS 1.2 AEAD" \
             0 \
             -s "Read from client: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small client packet TLS 1.2 AEAD shorter tag" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=1 \
@@ -6595,7 +6767,6 @@ run_test    "Small client packet TLS 1.2 AEAD shorter tag" \
 # Tests for small client packets in DTLS
 
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small client packet DTLS 1.2" \
             "$P_SRV dtls=1 force_version=dtls12" \
             "$P_CLI dtls=1 request_size=1 \
@@ -6604,7 +6775,6 @@ run_test    "Small client packet DTLS 1.2" \
             -s "Read from client: 1 bytes read"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small client packet DTLS 1.2, without EtM" \
             "$P_SRV dtls=1 force_version=dtls12 etm=0" \
             "$P_CLI dtls=1 request_size=1 \
@@ -6614,35 +6784,30 @@ run_test    "Small client packet DTLS 1.2, without EtM" \
 
 # Tests for small server packets
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small server packet TLS 1.2 BlockCipher" \
             "$P_SRV response_size=1 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
             -c "Read from server: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small server packet TLS 1.2 BlockCipher, without EtM" \
             "$P_SRV response_size=1 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA etm=0" \
             0 \
             -c "Read from server: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small server packet TLS 1.2 BlockCipher larger MAC" \
             "$P_SRV response_size=1 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384" \
             0 \
             -c "Read from server: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small server packet TLS 1.2 AEAD" \
             "$P_SRV response_size=1 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CCM" \
             0 \
             -c "Read from server: 1 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small server packet TLS 1.2 AEAD shorter tag" \
             "$P_SRV response_size=1 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CCM-8" \
@@ -6652,7 +6817,6 @@ run_test    "Small server packet TLS 1.2 AEAD shorter tag" \
 # Tests for small server packets in DTLS
 
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small server packet DTLS 1.2" \
             "$P_SRV dtls=1 response_size=1 force_version=dtls12" \
             "$P_CLI dtls=1 \
@@ -6661,7 +6825,6 @@ run_test    "Small server packet DTLS 1.2" \
             -c "Read from server: 1 bytes read"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Small server packet DTLS 1.2, without EtM" \
             "$P_SRV dtls=1 response_size=1 force_version=dtls12 etm=0" \
             "$P_CLI dtls=1 \
@@ -6676,7 +6839,6 @@ fragments_for_write() {
     echo "$(( ( $1 + $MAX_OUT_LEN - 1 ) / $MAX_OUT_LEN ))"
 }
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large client packet TLS 1.2 BlockCipher" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=16384 \
@@ -6685,7 +6847,6 @@ run_test    "Large client packet TLS 1.2 BlockCipher" \
             -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
             -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large client packet TLS 1.2 BlockCipher, without EtM" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=16384 etm=0 \
@@ -6693,7 +6854,6 @@ run_test    "Large client packet TLS 1.2 BlockCipher, without EtM" \
             0 \
             -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large client packet TLS 1.2 BlockCipher larger MAC" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=16384 \
@@ -6702,7 +6862,6 @@ run_test    "Large client packet TLS 1.2 BlockCipher larger MAC" \
             -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
             -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large client packet TLS 1.2 AEAD" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=16384 \
@@ -6711,7 +6870,6 @@ run_test    "Large client packet TLS 1.2 AEAD" \
             -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
             -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large client packet TLS 1.2 AEAD shorter tag" \
             "$P_SRV force_version=tls12" \
             "$P_CLI request_size=16384 \
@@ -6721,14 +6879,12 @@ run_test    "Large client packet TLS 1.2 AEAD shorter tag" \
             -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 # The tests below fail when the server's OUT_CONTENT_LEN is less than 16384.
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large server packet TLS 1.2 BlockCipher" \
             "$P_SRV response_size=16384 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
             -c "Read from server: 16384 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large server packet TLS 1.2 BlockCipher, without EtM" \
             "$P_SRV response_size=16384 force_version=tls12" \
             "$P_CLI etm=0 force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
@@ -6736,14 +6892,12 @@ run_test    "Large server packet TLS 1.2 BlockCipher, without EtM" \
             -s "16384 bytes written in 1 fragments" \
             -c "Read from server: 16384 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large server packet TLS 1.2 BlockCipher larger MAC" \
             "$P_SRV response_size=16384 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384" \
             0 \
             -c "Read from server: 16384 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large server packet TLS 1.2 BlockCipher, without EtM, truncated MAC" \
             "$P_SRV response_size=16384 trunc_hmac=1 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA trunc_hmac=1 etm=0" \
@@ -6751,14 +6905,12 @@ run_test    "Large server packet TLS 1.2 BlockCipher, without EtM, truncated MAC
             -s "16384 bytes written in 1 fragments" \
             -c "Read from server: 16384 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large server packet TLS 1.2 AEAD" \
             "$P_SRV response_size=16384 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CCM" \
             0 \
             -c "Read from server: 16384 bytes read"
 
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "Large server packet TLS 1.2 AEAD shorter tag" \
             "$P_SRV response_size=16384 force_version=tls12" \
             "$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-256-CCM-8" \
@@ -8329,10 +8481,8 @@ run_test    "DTLS fragmenting: proxy MTU + 3d, nbio" \
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_gnutls
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: gnutls server, DTLS 1.2" \
             "$G_SRV -u" \
             "$P_CLI dtls=1 debug_level=2 \
@@ -8353,11 +8503,9 @@ run_test    "DTLS fragmenting: gnutls server, DTLS 1.2" \
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_gnutls
 requires_not_i686
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: gnutls client, DTLS 1.2" \
             "$P_SRV dtls=1 debug_level=2 \
              crt_file=data_files/server7_int-ca.crt \
@@ -8370,9 +8518,7 @@ run_test    "DTLS fragmenting: gnutls client, DTLS 1.2" \
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: openssl server, DTLS 1.2" \
             "$O_SRV -dtls1_2 -verify 10" \
             "$P_CLI dtls=1 debug_level=2 \
@@ -8386,9 +8532,7 @@ run_test    "DTLS fragmenting: openssl server, DTLS 1.2" \
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: openssl client, DTLS 1.2" \
             "$P_SRV dtls=1 debug_level=2 \
              crt_file=data_files/server7_int-ca.crt \
@@ -8406,10 +8550,8 @@ requires_gnutls_next
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 client_needs_more_time 4
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: 3d, gnutls server, DTLS 1.2" \
             -p "$P_PXY drop=8 delay=8 duplicate=8" \
             "$G_NEXT_SRV -u" \
@@ -8425,10 +8567,8 @@ requires_gnutls_next
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 client_needs_more_time 4
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: 3d, gnutls client, DTLS 1.2" \
             -p "$P_PXY drop=8 delay=8 duplicate=8" \
             "$P_SRV dtls=1 debug_level=2 \
@@ -8448,10 +8588,8 @@ skip_next_test
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 client_needs_more_time 4
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: 3d, openssl server, DTLS 1.2" \
             -p "$P_PXY drop=8 delay=8 duplicate=8" \
             "$O_SRV -dtls1_2 -verify 10" \
@@ -8467,10 +8605,8 @@ skip_next_test
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 client_needs_more_time 4
 requires_max_content_len 2048
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS fragmenting: 3d, openssl client, DTLS 1.2" \
             -p "$P_PXY drop=8 delay=8 duplicate=8" \
             "$P_SRV dtls=1 debug_level=2 \
@@ -9186,6 +9322,7 @@ run_test    "DTLS proxy: delay ChangeCipherSpec" \
 
 # Tests for reordering support with DTLS
 
+requires_certificate_authentication
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS reordering: Buffer out-of-order handshake message on client" \
             -p "$P_PXY delay_srv=ServerHello" \
@@ -9203,6 +9340,7 @@ run_test    "DTLS reordering: Buffer out-of-order handshake message on client" \
             -S "Injecting buffered CCS message" \
             -S "Remember CCS message"
 
+requires_certificate_authentication
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS reordering: Buffer out-of-order handshake message fragment on client" \
             -p "$P_PXY delay_srv=ServerHello" \
@@ -9226,6 +9364,7 @@ run_test    "DTLS reordering: Buffer out-of-order handshake message fragment on
 # Certificate message; at the time of writing, together these are aroudn 1200b
 # in size, so that the bound below ensures that the certificate can be reassembled
 # while keeping the ServerKeyExchange.
+requires_certificate_authentication
 requires_config_value_at_least "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 1300
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS reordering: Buffer out-of-order hs msg before reassembling next" \
@@ -9248,6 +9387,7 @@ run_test    "DTLS reordering: Buffer out-of-order hs msg before reassembling nex
 # The size constraints ensure that the delayed certificate message can't
 # be reassembled while keeping the ServerKeyExchange message, but it can
 # when dropping it first.
+requires_certificate_authentication
 requires_config_value_at_least "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 900
 requires_config_value_at_most "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 1299
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
@@ -9268,6 +9408,7 @@ run_test    "DTLS reordering: Buffer out-of-order hs msg before reassembling nex
             -S "Injecting buffered CCS message" \
             -S "Remember CCS message"
 
+requires_certificate_authentication
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS reordering: Buffer out-of-order handshake message on server" \
             -p "$P_PXY delay_cli=Certificate" \
@@ -9285,6 +9426,7 @@ run_test    "DTLS reordering: Buffer out-of-order handshake message on server" \
             -S "Injecting buffered CCS message" \
             -S "Remember CCS message"
 
+requires_certificate_authentication
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS reordering: Buffer out-of-order CCS message on client"\
             -p "$P_PXY delay_srv=NewSessionTicket" \
@@ -9302,6 +9444,7 @@ run_test    "DTLS reordering: Buffer out-of-order CCS message on client"\
             -S "Injecting buffered CCS message" \
             -S "Remember CCS message"
 
+requires_certificate_authentication
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS reordering: Buffer out-of-order CCS message on server"\
             -p "$P_PXY delay_cli=ClientKeyExchange" \
@@ -9439,6 +9582,7 @@ run_test    "DTLS proxy: 3d, max handshake, nbio" \
 
 client_needs_more_time 4
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "DTLS proxy: 3d, min handshake, resumption" \
             -p "$P_PXY drop=5 delay=5 duplicate=5" \
             "$P_SRV dtls=1 dgram_packing=0 hs_timeout=500-10000 tickets=0 auth_mode=none \
@@ -9454,6 +9598,7 @@ run_test    "DTLS proxy: 3d, min handshake, resumption" \
 
 client_needs_more_time 4
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CACHE_C
 run_test    "DTLS proxy: 3d, min handshake, resumption, nbio" \
             -p "$P_PXY drop=5 delay=5 duplicate=5" \
             "$P_SRV dtls=1 dgram_packing=0 hs_timeout=500-10000 tickets=0 auth_mode=none \
@@ -10184,9 +10329,9 @@ run_test    "TLS 1.3: HRR check, ciphersuite TLS_AES_256_GCM_SHA384 - openssl" \
             -c "Protocol is TLSv1.3" \
             -c "HTTP/1.0 200 ok"
 
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
 requires_gnutls_tls1_3
 requires_gnutls_next_no_ticket
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
 requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
@@ -10200,9 +10345,9 @@ run_test    "TLS 1.3: HRR check, ciphersuite TLS_AES_128_GCM_SHA256 - gnutls" \
             -c "Protocol is TLSv1.3" \
             -c "HTTP/1.0 200 OK"
 
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
 requires_gnutls_tls1_3
 requires_gnutls_next_no_ticket
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
 requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C