Make variable in ssl_write_client_key_exchange() more descriptive
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 62c3695..f2e2275 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -3018,7 +3018,9 @@
 static int ssl_write_client_key_exchange( mbedtls_ssl_context *ssl )
 {
     int ret;
-    size_t i, n;
+
+    size_t header_len;
+    size_t content_len;
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
         ssl->transform_negotiate->ciphersuite_info;
 
@@ -3030,16 +3032,16 @@
         /*
          * DHM key exchange -- send G^X mod P
          */
-        n = ssl->handshake->dhm_ctx.len;
+        content_len = ssl->handshake->dhm_ctx.len;
 
-        ssl->out_msg[4] = (unsigned char)( n >> 8 );
-        ssl->out_msg[5] = (unsigned char)( n      );
-        i = 6;
+        ssl->out_msg[4] = (unsigned char)( content_len >> 8 );
+        ssl->out_msg[5] = (unsigned char)( content_len      );
+        header_len = 6;
 
         ret = mbedtls_dhm_make_public( &ssl->handshake->dhm_ctx,
-                                (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
-                               &ssl->out_msg[i], n,
-                                ssl->conf->f_rng, ssl->conf->p_rng );
+                           (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
+                           &ssl->out_msg[header_len], content_len,
+                           ssl->conf->f_rng, ssl->conf->p_rng );
         if( ret != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_public", ret );
@@ -3050,10 +3052,10 @@
         MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
 
         if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
-                                      ssl->handshake->premaster,
-                                      MBEDTLS_PREMASTER_SIZE,
-                                     &ssl->handshake->pmslen,
-                                      ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
+                                   ssl->handshake->premaster,
+                                   MBEDTLS_PREMASTER_SIZE,
+                                   &ssl->handshake->pmslen,
+                                   ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
             return( ret );
@@ -3081,7 +3083,7 @@
 
         psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
 
-        i = 4;
+        header_len = 4;
 
         /*
          * Generate EC private key for ECDHE exchange.
@@ -3133,9 +3135,10 @@
         }
 
         /* Copy ECPoint structure to outgoing message buffer. */
-        ssl->out_msg[i] = own_pubkey_ecpoint_len;
-        memcpy( ssl->out_msg + i + 1, own_pubkey_ecpoint, own_pubkey_ecpoint_len );
-        n = own_pubkey_ecpoint_len + 1;
+        ssl->out_msg[header_len] = own_pubkey_ecpoint_len;
+        memcpy( ssl->out_msg + header_len + 1,
+                own_pubkey_ecpoint, own_pubkey_ecpoint_len );
+        content_len = own_pubkey_ecpoint_len + 1;
 
         /* Compute ECDH shared secret. */
         status = psa_key_agreement( &generator,
@@ -3185,7 +3188,7 @@
         /*
          * ECDH key exchange -- send client public value
          */
-        i = 4;
+        header_len = 4;
 
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
         if( ssl->handshake->ecrs_enabled )
@@ -3198,8 +3201,8 @@
 #endif
 
         ret = mbedtls_ecdh_make_public( &ssl->handshake->ecdh_ctx,
-                                &n,
-                                &ssl->out_msg[i], 1000,
+                                &content_len,
+                                &ssl->out_msg[header_len], 1000,
                                 ssl->conf->f_rng, ssl->conf->p_rng );
         if( ret != 0 )
         {
@@ -3217,19 +3220,19 @@
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
         if( ssl->handshake->ecrs_enabled )
         {
-            ssl->handshake->ecrs_n = n;
+            ssl->handshake->ecrs_n = content_len;
             ssl->handshake->ecrs_state = ssl_ecrs_cke_ecdh_calc_secret;
         }
 
 ecdh_calc_secret:
         if( ssl->handshake->ecrs_enabled )
-            n = ssl->handshake->ecrs_n;
+            content_len = ssl->handshake->ecrs_n;
 #endif
         if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
-                                      &ssl->handshake->pmslen,
-                                       ssl->handshake->premaster,
-                                       MBEDTLS_MPI_MAX_SIZE,
-                                       ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
+                                   &ssl->handshake->pmslen,
+                                   ssl->handshake->premaster,
+                                   MBEDTLS_MPI_MAX_SIZE,
+                                   ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
@@ -3261,26 +3264,28 @@
             return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
         }
 
-        i = 4;
-        n = ssl->conf->psk_identity_len;
+        header_len = 4;
+        content_len = ssl->conf->psk_identity_len;
 
-        if( i + 2 + n > MBEDTLS_SSL_OUT_CONTENT_LEN )
+        if( header_len + 2 + content_len > MBEDTLS_SSL_OUT_CONTENT_LEN )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "psk identity too long or "
                                         "SSL buffer too short" ) );
             return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
         }
 
-        ssl->out_msg[i++] = (unsigned char)( n >> 8 );
-        ssl->out_msg[i++] = (unsigned char)( n      );
+        ssl->out_msg[header_len++] = (unsigned char)( content_len >> 8 );
+        ssl->out_msg[header_len++] = (unsigned char)( content_len      );
 
-        memcpy( ssl->out_msg + i, ssl->conf->psk_identity, ssl->conf->psk_identity_len );
-        i += ssl->conf->psk_identity_len;
+        memcpy( ssl->out_msg + header_len,
+                ssl->conf->psk_identity,
+                ssl->conf->psk_identity_len );
+        header_len += ssl->conf->psk_identity_len;
 
 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
         if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK )
         {
-            n = 0;
+            content_len = 0;
         }
         else
 #endif
@@ -3293,7 +3298,8 @@
                 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
-            if( ( ret = ssl_write_encrypted_pms( ssl, i, &n, 2 ) ) != 0 )
+            if( ( ret = ssl_write_encrypted_pms( ssl, header_len,
+                                                 &content_len, 2 ) ) != 0 )
                 return( ret );
         }
         else
@@ -3310,21 +3316,22 @@
             /*
              * ClientDiffieHellmanPublic public (DHM send G^X mod P)
              */
-            n = ssl->handshake->dhm_ctx.len;
+            content_len = ssl->handshake->dhm_ctx.len;
 
-            if( i + 2 + n > MBEDTLS_SSL_OUT_CONTENT_LEN )
+            if( header_len + 2 + content_len >
+                MBEDTLS_SSL_OUT_CONTENT_LEN )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "psk identity or DHM size too long"
                                             " or SSL buffer too short" ) );
                 return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
             }
 
-            ssl->out_msg[i++] = (unsigned char)( n >> 8 );
-            ssl->out_msg[i++] = (unsigned char)( n      );
+            ssl->out_msg[header_len++] = (unsigned char)( content_len >> 8 );
+            ssl->out_msg[header_len++] = (unsigned char)( content_len      );
 
             ret = mbedtls_dhm_make_public( &ssl->handshake->dhm_ctx,
                     (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
-                    &ssl->out_msg[i], n,
+                    &ssl->out_msg[header_len], content_len,
                     ssl->conf->f_rng, ssl->conf->p_rng );
             if( ret != 0 )
             {
@@ -3346,8 +3353,10 @@
             /*
              * ClientECDiffieHellmanPublic public;
              */
-            ret = mbedtls_ecdh_make_public( &ssl->handshake->ecdh_ctx, &n,
-                    &ssl->out_msg[i], MBEDTLS_SSL_OUT_CONTENT_LEN - i,
+            ret = mbedtls_ecdh_make_public( &ssl->handshake->ecdh_ctx,
+                    &content_len,
+                    &ssl->out_msg[header_len],
+                    MBEDTLS_SSL_OUT_CONTENT_LEN - header_len,
                     ssl->conf->f_rng, ssl->conf->p_rng );
             if( ret != 0 )
             {
@@ -3388,8 +3397,9 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
     if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA )
     {
-        i = 4;
-        if( ( ret = ssl_write_encrypted_pms( ssl, i, &n, 0 ) ) != 0 )
+        header_len = 4;
+        if( ( ret = ssl_write_encrypted_pms( ssl, header_len,
+                                             &content_len, 0 ) ) != 0 )
             return( ret );
     }
     else
@@ -3397,10 +3407,12 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
     if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
     {
-        i = 4;
+        header_len = 4;
 
         ret = mbedtls_ecjpake_write_round_two( &ssl->handshake->ecjpake_ctx,
-                ssl->out_msg + i, MBEDTLS_SSL_OUT_CONTENT_LEN - i, &n,
+                ssl->out_msg + header_len,
+                MBEDTLS_SSL_OUT_CONTENT_LEN - header_len,
+                &content_len,
                 ssl->conf->f_rng, ssl->conf->p_rng );
         if( ret != 0 )
         {
@@ -3425,7 +3437,7 @@
         return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
     }
 
-    ssl->out_msglen  = i + n;
+    ssl->out_msglen  = header_len + content_len;
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE;