/*
 * tcp.c	TCP-specific functions.
 *
 * Version:	$Id: c4ebe215965e7ebb3edeef18096cda04882d9aa0 $
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 *
 * Copyright (C) 2009 Dante http://dante.net
 */

RCSID("$Id: c4ebe215965e7ebb3edeef18096cda04882d9aa0 $")

#include	<freeradius-devel/libradius.h>

#ifdef WITH_TCP

/* FIXME: into common RADIUS header? */
#define MAX_PACKET_LEN 4096

RADIUS_PACKET *fr_tcp_recv(int sockfd, int flags)
{
	RADIUS_PACKET *packet = rad_alloc(NULL, false);

	if (!packet) return NULL;

	packet->sockfd = sockfd;

	if (fr_tcp_read_packet(packet, flags) != 1) {
		rad_free(&packet);
		return NULL;
	}

	return packet;
}


/*
 *	Receives a packet, assuming that the RADIUS_PACKET structure
 *	has been filled out already.
 *
 *	This ASSUMES that the packet is allocated && fields
 *	initialized.
 *
 *	This ASSUMES that the socket is marked as O_NONBLOCK, which
 *	the function above does set, if your system supports it.
 *
 *	Calling this function MAY change sockfd,
 *	if src_ipaddr.af == AF_UNSPEC.
 */
int fr_tcp_read_packet(RADIUS_PACKET *packet, int flags)
{
	ssize_t len;

	/*
	 *	No data allocated.  Read the 4-byte header into
	 *	a temporary buffer.
	 */
	if (!packet->data) {
		int packet_len;

		len = recv(packet->sockfd, packet->vector + packet->data_len,
			   4 - packet->data_len, 0);
		if (len == 0) return -2; /* clean close */

#ifdef ECONNRESET
		if ((len < 0) && (errno == ECONNRESET)) { /* forced */
			return -2;
		}
#endif

		if (len < 0) {
			fr_strerror_printf("Error receiving packet: %s",
				   fr_syserror(errno));
			return -1;
		}

		packet->data_len += len;
		if (packet->data_len < 4) { /* want more data */
			return 0;
		}

		packet_len = (packet->vector[2] << 8) | packet->vector[3];

		if (packet_len < RADIUS_HDR_LEN) {
			fr_strerror_printf("Discarding packet: Smaller than RFC minimum of 20 bytes");
			return -1;
		}

		/*
		 *	If the packet is too big, then the socket is bad.
		 */
		if (packet_len > MAX_PACKET_LEN) {
			fr_strerror_printf("Discarding packet: Larger than RFC limitation of 4096 bytes");
			return -1;
		}

		packet->data = talloc_array(packet, uint8_t, packet_len);
		if (!packet->data) {
			fr_strerror_printf("Out of memory");
			return -1;
		}

		packet->data_len = packet_len;
		packet->partial = 4;
		memcpy(packet->data, packet->vector, 4);
	}

	/*
	 *	Try to read more data.
	 */
	len = recv(packet->sockfd, packet->data + packet->partial,
		   packet->data_len - packet->partial, 0);
	if (len == 0) return -2; /* clean close */

#ifdef ECONNRESET
	if ((len < 0) && (errno == ECONNRESET)) { /* forced */
		return -2;
	}
#endif

	if (len < 0) {
		fr_strerror_printf("Error receiving packet: %s", fr_syserror(errno));
		return -1;
	}

	packet->partial += len;

	if (packet->partial < packet->data_len) {
		return 0;
	}

	/*
	 *	See if it's a well-formed RADIUS packet.
	 */
	if (!rad_packet_ok(packet, flags, NULL)) {
		return -1;
	}

	/*
	 *	Explicitly set the VP list to empty.
	 */
	packet->vps = NULL;

	if (fr_debug_lvl) {
		char ip_buf[128], buffer[256];

		if (packet->src_ipaddr.af != AF_UNSPEC) {
			inet_ntop(packet->src_ipaddr.af,
				  &packet->src_ipaddr.ipaddr,
				  ip_buf, sizeof(ip_buf));
			snprintf(buffer, sizeof(buffer), "host %s port %d",
				 ip_buf, packet->src_port);
		} else {
			snprintf(buffer, sizeof(buffer), "socket %d",
				 packet->sockfd);
		}


		if (is_radius_code(packet->code)) {
			DEBUG("Received %s packet from %s",
			      fr_packet_codes[packet->code], buffer);
		} else {
			DEBUG("Received packet from %s code %d",
			      buffer, packet->code);
		}
		DEBUG(", id=%d, length=%zu\n", packet->id, packet->data_len);
	}

	return 1;		/* done reading the packet */
}

#endif /* WITH_TCP */
