/* This file is part of ToaruOS and is released under the terms
 * of the NCSA / University of Illinois License - see LICENSE.md
 * Copyright (C) 2014 Kevin Lange
 */
#include <module.h>
#include <ipv4.h>
#include <printf.h>

uint32_t ip_aton(const char * in) {
	char ip[16];
	char * c = ip;
	int out[4];
	char * i;
	memcpy(ip, in, strlen(in) < 15 ? strlen(in) + 1 : 15);
	ip[15] = '\0';

	i = (char *)lfind(c, '.');
	*i = '\0';
	out[0] = atoi(c);
	c += strlen(c) + 1;

	i = (char *)lfind(c, '.');
	*i = '\0';
	out[1] = atoi(c);
	c += strlen(c) + 1;

	i = (char *)lfind(c, '.');
	*i = '\0';
	out[2] = atoi(c);
	c += strlen(c) + 1;

	out[3] = atoi(c);

	return ((out[0] << 24) | (out[1] << 16) | (out[2] << 8) | (out[3]));
}

void ip_ntoa(uint32_t src_addr, char * out) {
	sprintf(out, "%d.%d.%d.%d",
		(src_addr & 0xFF000000) >> 24,
		(src_addr & 0xFF0000) >> 16,
		(src_addr & 0xFF00) >> 8,
		(src_addr & 0xFF));
}

uint16_t calculate_ipv4_checksum(struct ipv4_packet * p) {
	uint32_t sum = 0;
	uint16_t * s = (uint16_t *)p;

	/* TODO: Checksums for options? */
	for (int i = 0; i < 10; ++i) {
		sum += ntohs(s[i]);
	}

	if (sum > 0xFFFF) {
		sum = (sum >> 16) + (sum & 0xFFFF);
	}

	return ~(sum & 0xFFFF) & 0xFFFF;
}

uint16_t calculate_tcp_checksum(struct tcp_check_header * p, struct tcp_header * h, void * d, size_t payload_size) {
	uint32_t sum = 0;
	uint16_t * s = (uint16_t *)p;

	/* TODO: Checksums for options? */
	for (int i = 0; i < 6; ++i) {
		sum += ntohs(s[i]);
		if (sum > 0xFFFF) {
			sum = (sum >> 16) + (sum & 0xFFFF);
		}
	}

	s = (uint16_t *)h;
	for (int i = 0; i < 10; ++i) {
		sum += ntohs(s[i]);
		if (sum > 0xFFFF) {
			sum = (sum >> 16) + (sum & 0xFFFF);
		}
	}

	uint16_t d_words = payload_size / 2;

	s = (uint16_t *)d;
	for (unsigned int i = 0; i < d_words; ++i) {
		sum += ntohs(s[i]);
		if (sum > 0xFFFF) {
			sum = (sum >> 16) + (sum & 0xFFFF);
		}
	}

	if (d_words * 2 != payload_size) {
		uint8_t * t = (uint8_t *)d;
		uint8_t tmp[2];
		tmp[0] = t[d_words * sizeof(uint16_t)];
		tmp[1] = 0;

		uint16_t * f = (uint16_t *)tmp;

		sum += ntohs(f[0]);
		if (sum > 0xFFFF) {
			sum = (sum >> 16) + (sum & 0xFFFF);
		}
	}

	return ~(sum & 0xFFFF) & 0xFFFF;
}

static int init(void) {
	return 0;
}

static int fini(void) {
	return 0;
}

MODULE_DEF(net, init, fini);