feature: send packets (reponse not working tho)

include/packet.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <stdint.h>
+
+#include "scan.h"
+
+struct pshdr {
+	uint32_t src_addr;
+	uint32_t dst_addr;
+	uint8_t placeholder;
+	uint8_t protocol;
+	uint16_t tcp_length;
+};
+
+int send_packets(const struct scan *data, int sockfd);
+unsigned short checksum(void *data, int len);