/* l2tpd.c
 * Copyright (C) 1997-2000 SpellCaster Telecommunications Inc.
 * $Id: l2tpd.c,v 1.3 2004/07/12 18:41:46 bcrl Exp $
 * Released under the GNU Public License. See LICENSE file for details.
 *
 * Userland component of L2TP session handling.  Manages control packets of 
 * sessions.
 */
#define PKT_SIZE	4096

#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <stdio.h>
#include <stdlib.h>

#include "l2tp_linux.h"

#if 0
#include "l2tp.h"
#endif

void dump_packet(unsigned char *buf, int len);

static unsigned long strtoip(char *str)
{
	unsigned long a, b, c, d;
	if (4 != sscanf(str, "%lu.%lu.%lu.%lu", &a, &b, &c, &d)) {
		fprintf(stderr, "invalid ip address.\n");
		exit(1);
	}
	return (a << 24 | b << 16 | c << 8 | d);
}

int main(int argc, char *argv[])
{
	struct sockaddr_in addr;
	unsigned char *buf;
	int s;

if (argc < 3) {
	fprintf(stderr, "need ip addresses <local> <remote>.\n");
	exit(1);
}
	s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (s < 0) {
		perror("socket");
		return 1;
	}

	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(strtoip(argv[1]));	//htonl(INADDR_ANY);
	addr.sin_port = htons(1701);

	if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
		perror("bind");
		return 1;
	}

	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(strtoip(argv[2]));	//htonl(INADDR_ANY);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	addr.sin_port = htons(1701);

	if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
		perror("connect");
		return 1;
	}

#if 0
	switch (fork()) {
	case 0:
		break;
	case -1:
		perror("fork");
		return 1;
	default:
		return 0;
	}

	close(0);
	close(1);
	close(2);

	/* we're a daemon now =) */
#endif

	buf = malloc(PKT_SIZE);
	for (;;) {
		int addrlen = sizeof(addr);
		int len;

		len = recvfrom(s, buf, PKT_SIZE, 0, (struct sockaddr *)&addr, &addrlen);

		if (len > 0) {
			//struct sk_buff *skb = calloc(sizeof(skb), 1);

			//skb->len = len;
			//skb->head = skb->data = buf;

			printf("from: %08x:%04x\n", (int)ntohl(addr.sin_addr.s_addr), ntohs(addr.sin_port));
			dump_packet(buf, len);

			//l2tp_udp_recv(skb);

			buf = malloc(PKT_SIZE);
		}
	}

	return 0;
}

#include <ctype.h>
static inline char tohex(unsigned char foo)
{
	if (foo >= 10)
		return 'a' + foo - 0xa;
	return foo + '0';
}

void dump_packet(unsigned char *buf, int len)
{
	char line[80];
	int x, i;
	printf("Packet len: %d = 0x%x\n\n", len, len);

	for (x=i=0; i<len; i++) {
		if (!x) {
			line[x++] = tohex((i >> 12) & 0xf);
			line[x++] = tohex((i >> 8) & 0xf);
			line[x++] = tohex((i >> 4) & 0xf);
			line[x++] = tohex(i & 0xf);
			line[x++] = ':';
			x++;
		}

		line[x++] = tohex(buf[i] >> 4);
		line[x++] = tohex(buf[i] & 0xf);

		if (3 == (i % 4))
			x++;

		line[(i % 16) + 48] = isprint(buf[i]) ? buf[i] : '.';

		if (15 == (i % 16)) {
			line[16 + 48] = 0;
			puts(line);
			x = 0;
		}
	}

	if (i % 16) {
		line[48 + (i % 16)] = 0;
		for (; i % 16; i++) {
			line[x++] = ' ';
			line[x++] = ' ';

			if (3 == (i % 4))
				x++;
		}
		puts(line);
	}

	putchar('\n');
}