From 9b807e35c203897b3392dcda3ca6319e52171b7f Mon Sep 17 00:00:00 2001
From: YEZZFUSL <18398621+yezzfusl@users.noreply.github.com>
Date: Fri, 16 Aug 2024 18:16:26 -0400
Subject: [PATCH] Enhance CAN filter (Advanced filter structure, Timing
 requirements, Custom filter functions, Error frame detection, Multiple
 filters, VOltage thresholds, Dilter statistics, Dynamic filter addition.)

---
 src/can_filter.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 128 insertions(+), 1 deletion(-)

diff --git a/src/can_filter.c b/src/can_filter.c
index 5efd6b0..c338205 100644
--- a/src/can_filter.c
+++ b/src/can_filter.c
@@ -1,5 +1,132 @@
 #include "can_filter.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define MAX_FILTERS 16
+#define SAMPLING_RATE 1000 // Hz
+#define VOLTAGE_THRESHOLD 2.5 // Volts
+#define CAN_ERROR_FRAME 0x20000000 // Error frame bit in CAN ID
+
+// Advanced filter structure
+typedef struct {
+    struct can_filter base;
+    uint8_t priority;
+    uint64_t timestamp;
+    double signal_strength;
+    int (*custom_filter_func)(const struct can_frame *);
+} advanced_can_filter;
+
+// Global filter array
+static advanced_can_filter filter_array[MAX_FILTERS];
+static int filter_count = 0;
+
+// Function prototypes
+static double calculate_signal_strength(const struct can_frame *frame);
+static int check_timing_requirements(const struct can_frame *frame, const advanced_can_filter *filter);
+static int apply_custom_filter(const struct can_frame *frame, const advanced_can_filter *filter);
+static int detect_error_frame(const struct can_frame *frame);
 
 int apply_can_filter(const struct can_frame *frame, const struct can_filter *filter) {
-    return (frame->can_id & filter->can_mask) == (filter->can_id & filter->can_mask);
+    if (filter_count == 0) {
+        printf("Warning: No filters configured\n");
+        return 1; // Accept all frames if no filters are set
+    }
+
+    for (int i = 0; i < filter_count; i++) {
+        const advanced_can_filter *adv_filter = &filter_array[i];
+        
+        // Basic ID and mask check
+        if ((frame->can_id & adv_filter->base.can_mask) != (adv_filter->base.can_id & adv_filter->base.can_mask)) {
+            continue;
+        }
+
+        // Check signal strength
+        double signal_strength = calculate_signal_strength(frame);
+        if (signal_strength < adv_filter->signal_strength) {
+            printf("Frame rejected due to weak signal strength: %.2f\n", signal_strength);
+            continue;
+        }
+
+        // Check timing requirements
+        if (!check_timing_requirements(frame, adv_filter)) {
+            continue;
+        }
+
+        // Apply custom filter function if available
+        if (!apply_custom_filter(frame, adv_filter)) {
+            continue;
+        }
+
+        // Check for error frames
+        if (detect_error_frame(frame)) {
+            printf("Error frame detected\n");
+            return 0;
+        }
+
+        // All checks passed, accept the frame
+        return 1;
+    }
+
+    return 0; // Frame doesn't match any filter
+}
+
+int add_advanced_filter(struct can_filter *base_filter, uint8_t priority, double min_signal_strength, 
+                        int (*custom_func)(const struct can_frame *)) {
+    if (filter_count >= MAX_FILTERS) {
+        printf("Error: Maximum number of filters reached\n");
+        return 0;
+    }
+
+    advanced_can_filter *new_filter = &filter_array[filter_count];
+    memcpy(&new_filter->base, base_filter, sizeof(struct can_filter));
+    new_filter->priority = priority;
+    new_filter->timestamp = time(NULL);
+    new_filter->signal_strength = min_signal_strength;
+    new_filter->custom_filter_func = custom_func;
+
+    filter_count++;
+    return 1;
+}
+
+static double calculate_signal_strength(const struct can_frame *frame) {
+    // Simulating signal strength calculation based on data bytes
+    double strength = 0;
+    for (int i = 0; i < frame->can_dlc; i++) {
+        strength += (double)frame->data[i] / 255.0;
+    }
+    return strength / frame->can_dlc * 5.0; // Normalize to 0-5V range
+}
+
+static int check_timing_requirements(const struct can_frame *frame, const advanced_can_filter *filter) {
+    uint64_t current_time = time(NULL);
+    double time_diff = difftime(current_time, filter->timestamp);
+    
+    // Check if the frame arrives within the expected time window
+    if (time_diff > 1.0 / SAMPLING_RATE) {
+        printf("Frame rejected due to timing requirements\n");
+        return 0;
+    }
+    return 1;
+}
+
+static int apply_custom_filter(const struct can_frame *frame, const advanced_can_filter *filter) {
+    if (filter->custom_filter_func != NULL) {
+        return filter->custom_filter_func(frame);
+    }
+    return 1; // No custom filter function, so pass
+}
+
+static int detect_error_frame(const struct can_frame *frame) {
+    return (frame->can_id & CAN_ERROR_FRAME) != 0;
+}
+
+void print_filter_stats() {
+    printf("Current filter configuration:\n");
+    for (int i = 0; i < filter_count; i++) {
+        printf("Filter %d: ID=0x%X, Mask=0x%X, Priority=%d, Min Signal Strength=%.2fV\n",
+               i, filter_array[i].base.can_id, filter_array[i].base.can_mask,
+               filter_array[i].priority, filter_array[i].signal_strength);
+    }
 }