#include <stdio.h>

#define __USE_GNU
#include <string.h>

#include <ctype.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>

#include "netpkt.h"

int pkt_memcmp(struct net_pkt *pkt, unsigned int offset, char *search, unsigned int size)
{

	if (offset >= pkt->size)
		return 1;

	/* nicht ueber das paket hinaus vergleichen */
	if (offset + size >= pkt->size)
		size = pkt->size - offset;

	return memcmp(pkt->buf + offset, search, size);
}

int pkt_memmem(struct net_pkt *pkt, unsigned int offset, char *search, unsigned int size)
{
	void *found;

	if (offset >= pkt->size)
		return -1;

	found = memmem(pkt->buf + offset, pkt->size, search, size);

	return (found == NULL) ? -1 : (found - (void *)pkt->buf);
}

struct net_pkt * pkt_merge(struct net_pkt *pkt1, struct net_pkt *pkt2)
{
	struct net_pkt *ret;
	ret = malloc(sizeof(struct net_pkt) + pkt1->size + pkt2->size);

	memcpy(&ret->addr, &pkt1->addr, sizeof(ret->addr));
	ret->size = pkt1->size + pkt2->size;

	memcpy(ret->buf, pkt1->buf, pkt1->size);
	memcpy(ret->buf + pkt1->size, pkt2->buf, pkt2->size);

	return ret;
}

char * pkt_ntoa(struct net_pkt *pkt)
{
	return inet_ntoa(pkt->addr.sin_addr);
}

unsigned short pkt_getport(struct net_pkt *pkt)
{
	return ntohs(pkt->addr.sin_port);
}

int pkt_sameaddr(struct net_pkt *pkt1, struct net_pkt *pkt2)
{
	return (pkt1->addr.sin_addr.s_addr == pkt2->addr.sin_addr.s_addr) &&
		(pkt1->addr.sin_port == pkt2->addr.sin_port);
}

int pkt_parse_int(struct net_pkt *pkt, unsigned int offset, int *val)
{
	unsigned char *max = pkt->buf + pkt->size;
	unsigned char *c = pkt->buf + offset;

	/* untere grenze abtesten */
	if (pkt->buf > c || c > max)
		return -1;

	*val = 0;

	/* ziffern einlesen */
	while (isdigit(*c) && c < max)
		*val = (*val * 10) + (*c++ - 0x30);

	return (c - (pkt->buf + offset));
}

int pkt_parse_ip(struct net_pkt *pkt, int offset, struct in_addr *ip)
{
	int i, tmp, count, pos = offset;
	ip->s_addr = 0;

	for (i = 0; i < 4; i++) {
		count = pkt_parse_int(pkt, pos, &tmp);
		pos += count;
		if (count == 0 || tmp < 0 || tmp > 255)
			return 0;

		ip->s_addr = ip->s_addr>>8 | tmp<<24;

		if (i != 3 && pkt->buf[pos++] != '.')
			return 0;
	}
	return pos - offset;
}

char * pkt_print(struct net_pkt *pkt)
{
	int pos = 0, i = 0, j;
	char *buf = malloc(pkt->size * 4 + 64);

	while (pos < pkt->size) {
		i += sprintf(buf + i, "%04X: ", pos);
		for (j = 0; j < 16; j++) {
			if (pos + j < pkt->size)
				i += sprintf(buf + i, "%02X", pkt->buf[pos + j]);
			else
				i += sprintf(buf + i, "  ");

			if (j % 2)
				buf[i++] = ' ';
		}

		for (j = 0; j < 16; j++) {
			if (pos + j < pkt->size) {
				unsigned char val = pkt->buf[pos + j];
				if (val >= 0x20 && val < 0x80)
					buf[i++] = val;
				else
					buf[i++] = '.';
			} else {
				buf[i++] = ' ';
			}
		}

		pos += 16;
		buf[i++] = '\r';
		buf[i++] = '\n';
	}
	buf[i] = 0;
	return buf;
}