Implement delete

firewall-server/server_includes/handlers.c

@@ -12,6 +12,7 @@
 #define HANDLER_INVRULE 2
 #define HANDLER_ILLEGALARG 3
 #define HANDLER_FOUND 4
+#define HANDLER_DELETEDRULE 5
 
 int handle_add_rule(char *data, size_t len) {
     // Add rule should provide a rule as per exercise 1 definitions.
@@ -34,6 +35,29 @@ end:
     return retval;
 }
 
+int handle_delete_rule(char *data, size_t len) {
+    int retval = HANDLER_OK;
+    struct Rule *parse_res = (struct Rule*)malloc(sizeof(struct Rule));
+
+    char *eptr = parse_rule(data, parse_res);
+    if (eptr == NULL) {
+        retval = HANDLER_INVRULE;
+        goto end;
+    } else if ((eptr - data) < len) {
+        // This means we've not consumed everything which means that there's extraneous data?
+        retval = HANDLER_INVRULE;
+        goto end;
+    }
+
+    if (delete_frame(parse_res) == 1) {
+        retval = HANDLER_DELETEDRULE;
+    }
+
+end:
+    free_rule(parse_res);
+    return retval;
+}
+
 int handle_check_rule(char *data, size_t len) {
     // Check if the specified IP and port is matched by any IP and port
     struct IP ip;
@@ -60,6 +84,7 @@ int handle_check_rule(char *data, size_t len) {
     return HANDLER_OK;
 }
 
+// Note: this function does not follow the usual return value conventions.
 int handle_list_rules(int sd) {
     return list_rules(sd);
 }

firewall-server/server_includes/persist.c

@@ -203,4 +203,51 @@ int list_rules(int sd) {
 end:
     pthread_rwlock_unlock(&persist_lock);
     return status;
+}
+
+// Returns 1 if something has been removed, 0 otherwise.
+int delete_frame(struct Rule* rule) {
+    pthread_rwlock_wrlock(&persist_lock);
+
+    struct Frame *previous = NULL;
+    struct Frame *frame_cursor = persist_head;
+    int hasChanged = 0;
+
+    while (frame_cursor != NULL && hasChanged == 0) {
+        struct Frame *next = frame_cursor->next;
+
+        if (compare_rule(rule, &frame_cursor->rule) == 0) {
+            struct LogFrame *log_cursor = frame_cursor->log;
+            while (log_cursor != NULL) {
+                struct LogFrame *next = log_cursor->next;
+                free(log_cursor);
+                log_cursor = next;
+            }
+
+            if (previous == NULL) {
+                // If the thing we're deleting is the first
+                persist_head = next;
+            } else {
+                previous->next = next;
+            }
+
+            if (frame_cursor->rule.ip.end != NULL) {
+                free(frame_cursor->rule.ip.end);
+            }
+
+            if (frame_cursor->rule.port.end != NULL) {
+                free(frame_cursor->rule.port.end);
+            }
+
+            free(frame_cursor);
+
+            hasChanged = 1;
+        }
+
+        previous = frame_cursor;
+        frame_cursor = next;
+    }
+
+    pthread_rwlock_unlock(&persist_lock);
+    return hasChanged;
 }

firewall-server/server_includes/sockets.c

@@ -146,6 +146,17 @@ void handle_connection(int *sdptr) {
             }
             break;
         }
+        case 'D': {
+            int status = handle_delete_rule(data, message_length);
+            if (status == HANDLER_INVRULE) {
+                response = "Rule invalid";
+            } else if (status == HANDLER_DELETEDRULE) {
+                response = "Rule deleted";
+            } else {
+                response = "Rule not found";
+            }
+            break;
+        }
         default: {
             response = "Illegal request";
             break;