Feature/mbedtls (#84)

* try to import mbedtls and build it

* add stubs socket class

* some boilterplate, read and write function implemented

* more boilterplate / current error in handshake because no CA cert is setup

* add something so skip ca verification, can ws curl https://google.com !

* cleanup / close implemented

* tweak CMakefiles

* typo in include

* update readme

* disable unittests

third_party/mbedtls/crypto/scripts/ecc-heap.sh

@@ -0,0 +1,74 @@
+#!/bin/sh
+
+# Measure heap usage (and performance) of ECC operations with various values of
+# the relevant tunable compile-time parameters.
+#
+# Usage (preferably on a 32-bit platform):
+# cmake -D CMAKE_BUILD_TYPE=Release .
+# scripts/ecc-heap.sh | tee ecc-heap.log
+
+set -eu
+
+CONFIG_H='include/mbedtls/config.h'
+
+if [ -r $CONFIG_H ]; then :; else
+    echo "$CONFIG_H not found" >&2
+    exit 1
+fi
+
+if grep -i cmake Makefile >/dev/null; then :; else
+    echo "Needs Cmake" >&2
+    exit 1
+fi
+
+if git status | grep -F $CONFIG_H >/dev/null 2>&1; then
+    echo "config.h not clean" >&2
+    exit 1
+fi
+
+CONFIG_BAK=${CONFIG_H}.bak
+cp $CONFIG_H $CONFIG_BAK
+
+cat << EOF >$CONFIG_H
+#define MBEDTLS_PLATFORM_C
+#define MBEDTLS_PLATFORM_MEMORY
+#define MBEDTLS_MEMORY_BUFFER_ALLOC_C
+#define MBEDTLS_MEMORY_DEBUG
+
+#define MBEDTLS_TIMING_C
+
+#define MBEDTLS_BIGNUM_C
+#define MBEDTLS_ECP_C
+#define MBEDTLS_ASN1_PARSE_C
+#define MBEDTLS_ASN1_WRITE_C
+#define MBEDTLS_ECDSA_C
+#define MBEDTLS_ECDH_C
+
+#define MBEDTLS_ECP_DP_SECP192R1_ENABLED
+#define MBEDTLS_ECP_DP_SECP224R1_ENABLED
+#define MBEDTLS_ECP_DP_SECP256R1_ENABLED
+#define MBEDTLS_ECP_DP_SECP384R1_ENABLED
+#define MBEDTLS_ECP_DP_SECP521R1_ENABLED
+#define MBEDTLS_ECP_DP_CURVE25519_ENABLED
+
+#include "check_config.h"
+
+//#define MBEDTLS_ECP_WINDOW_SIZE            6
+//#define MBEDTLS_ECP_FIXED_POINT_OPTIM      1
+EOF
+
+for F in 0 1; do
+    for W in 2 3 4 5 6; do
+        scripts/config.pl set MBEDTLS_ECP_WINDOW_SIZE $W
+        scripts/config.pl set MBEDTLS_ECP_FIXED_POINT_OPTIM $F
+        make benchmark >/dev/null 2>&1
+        echo "fixed point optim = $F, max window size = $W"
+        echo "--------------------------------------------"
+        programs/test/benchmark
+    done
+done
+
+# cleanup
+
+mv $CONFIG_BAK $CONFIG_H
+make clean