-int new_packet(short type, char *packet);
-int send_packet(int sockfd, int dest_ip, int dest_port, char *packet, int len);
-void dump_packet(char *packet, FILE *stream);
-int read_packet(int sockfd, char *packet);
+/* response messages */
+#define NSCTL_RESPONSE (1 << 5)
+#define NSCTL_RES_OK (NSCTL_RESPONSE | 1)
+#define NSCTL_RES_ERR (NSCTL_RESPONSE | 2)
+
+/* unpack errors */
+#define NSCTL_ERR_SHORT -1 // short packet
+#define NSCTL_ERR_LONG -2 // packet exceeds max, or trailing cr*p
+#define NSCTL_ERR_MAGIC -3 // invalid magic number
+#define NSCTL_ERR_TYPE -4 // unrecognised type
+
+#define NSCTL_MAX_PKT_SZ 4096
+
+struct nsctl_packet {
+ uint16_t magic;
+ uint8_t type;
+ uint8_t argc;
+ char argv[NSCTL_MAX_PKT_SZ - 4];
+} __attribute__ ((packed));
+
+#define NSCTL_MAX_ARG_SZ 512
+
+struct nsctl_args {
+ uint8_t len;
+ char value[NSCTL_MAX_ARG_SZ - 1];
+} __attribute__ ((packed));
+
+/* parsed packet */
+struct nsctl {
+ uint8_t type;
+ uint8_t argc;
+ char *argv[0xff];
+};
+
+int pack_control(uint8_t *data, int len, uint8_t type, int argc, char *argv[]);
+int unpack_control(struct nsctl *packet, uint8_t *data, int len);
+void dump_control(struct nsctl *control, FILE *stream);