From 62058329ff9000589ddba6454ff8ef8a551b7243 Mon Sep 17 00:00:00 2001
From: Fred Sundvik <fsundvik@gmail.com>
Date: Sun, 14 Feb 2016 21:13:16 +0200
Subject: [PATCH] Add crc32 validation of received frames

---
 serial_link/protocol/frame_validator.c    |  9 +++++-
 serial_link/tests/frame_validator_tests.c | 35 +++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/serial_link/protocol/frame_validator.c b/serial_link/protocol/frame_validator.c
index 1ffd3aad8..d3337f6e3 100644
--- a/serial_link/protocol/frame_validator.c
+++ b/serial_link/protocol/frame_validator.c
@@ -23,6 +23,7 @@ SOFTWARE.
 */
 
 #include "protocol/frame_validator.h"
+#include "protocol/frame_router.h"
 
 const uint32_t poly8_lookup[256] =
 {
@@ -101,5 +102,11 @@ static uint32_t crc32_byte(uint8_t *p, uint32_t bytelength)
 }
 
 void recv_frame(uint8_t* data, uint16_t size) {
-
+    if (size > 4) {
+        uint32_t frame_crc = *(uint32_t*)(data + size - 4);
+        uint32_t expected_crc = crc32_byte(data, size - 4);
+        if (frame_crc == expected_crc) {
+            route_frame(data, size-4);
+        }
+    }
 }
diff --git a/serial_link/tests/frame_validator_tests.c b/serial_link/tests/frame_validator_tests.c
index f6a4fcd84..1aca9f95f 100644
--- a/serial_link/tests/frame_validator_tests.c
+++ b/serial_link/tests/frame_validator_tests.c
@@ -42,3 +42,38 @@ Ensure(FrameValidator, doesnt_validate_frames_under_5_bytes) {
     recv_frame(data, 3);
     recv_frame(data, 4);
 }
+
+Ensure(FrameValidator, validates_one_byte_frame_with_correct_crc) {
+    uint8_t data[] = {0x44, 0x04, 0x6A, 0xB3, 0xA3};
+    expect(route_frame,
+        when(size, is_equal_to(1)),
+        when(data, is_equal_to_contents_of(data, 1))
+    );
+    recv_frame(data, 5);
+}
+
+Ensure(FrameValidator, does_not_validate_one_byte_frame_with_incorrect_crc) {
+    uint8_t data[] = {0x44, 0, 0, 0, 0};
+    never_expect(route_frame);
+    recv_frame(data, 5);
+}
+
+Ensure(FrameValidator, validates_four_byte_frame_with_correct_crc) {
+    uint8_t data[] = {0x44, 0x10, 0xFF, 0x00, 0x74, 0x4E, 0x30, 0xBA};
+    expect(route_frame,
+        when(size, is_equal_to(4)),
+        when(data, is_equal_to_contents_of(data, 4))
+    );
+    recv_frame(data, 8);
+}
+
+Ensure(FrameValidator, validates_five_byte_frame_with_correct_crc) {
+    //0xBA304E74
+    //0x470B99F4
+    uint8_t data[] = {1, 2, 3, 4, 5, 0xF4, 0x99, 0x0B, 0x47};
+    expect(route_frame,
+        when(size, is_equal_to(5)),
+        when(data, is_equal_to_contents_of(data, 5))
+    );
+    recv_frame(data, 9);
+}