/*
 * Create and destroy functions for twrtp_endp.
 */

#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>

#include <osmocom/core/talloc.h>
#include <osmocom/core/osmo_io.h>
#include <osmocom/core/utils.h>

#include <themwi/rtp/endp.h>
#include <themwi/rtp/twjit.h>
#include <themwi/rtp/rtp_basic_hdr.h>
#include <themwi/rtp/rtcp_defs.h>
#include "endp_internal.h"

/* We need to know maximum expected sizes of RTP and RTCP Rx packets
 * for osmo_io msgb allocation.  For RTP, the largest packet size in
 * 3GPP and IP-PSTN applications is 176 bytes: 12 bytes of RTP header
 * plus 160 bytes of payload for 20 ms of uncompressed G.711 audio
 * or CSData.  Of course there may be other applications that use
 * larger RTP packets, in which case we may have to add an API function
 * that overrides our default msgb alloc size setting - but let's
 * cross that bridge if and when we actually have such users.
 *
 * In case of RTCP, we fully process all received packets inside
 * the present library, hence we can set osmo_io msgb alloc size
 * based on what our RTCP Rx code can parse and make use of.  Any
 * additional RTCP Rx data, such as very long SDES strings, will
 * simply be truncated at osmo_io level - but the subsequent parsing
 * code will never get to those bits anyway.
 */

#define	MAX_RTP_RX_PACKET	(sizeof(struct rtp_basic_hdr) + 160)
#define	MAX_RTCP_RX_PACKET	(sizeof(struct rtcp_sr_rr_hdr) + \
					sizeof(struct rtcp_sr_block) + \
					sizeof(struct rtcp_rr_block) * 31)

struct twrtp_endp *twrtp_endp_create(void *ctx,
				     struct twrtp_jibuf_config *config)
{
	struct twrtp_endp *endp;

	endp = talloc_zero(ctx, struct twrtp_endp);
	if (!endp)
		return NULL;

	endp->iofd_rtp = osmo_iofd_setup(endp, -1, NULL,
					 OSMO_IO_FD_MODE_RECVFROM_SENDTO,
					 &_twrtp_endp_iops_rtp, endp);
	if (!endp->iofd_rtp) {
		talloc_free(endp);
		return NULL;
	}
	osmo_iofd_set_alloc_info(endp->iofd_rtp, MAX_RTP_RX_PACKET, 0);

	endp->iofd_rtcp = osmo_iofd_setup(endp, -1, NULL,
					  OSMO_IO_FD_MODE_RECVFROM_SENDTO,
					  &_twrtp_endp_iops_rtcp, endp);
	if (!endp->iofd_rtcp) {
		osmo_iofd_free(endp->iofd_rtp);
		talloc_free(endp);
		return NULL;
	}
	osmo_iofd_set_alloc_info(endp->iofd_rtcp, MAX_RTCP_RX_PACKET, 0);

	endp->twjit = twrtp_jibuf_create(endp, config);
	if (!endp->twjit) {
		osmo_iofd_free(endp->iofd_rtp);
		osmo_iofd_free(endp->iofd_rtcp);
		talloc_free(endp);
		return NULL;
	}

	endp->tx.ssrc = random();
	return endp;
}

void twrtp_endp_destroy(struct twrtp_endp *endp)
{
	osmo_iofd_free(endp->iofd_rtp);
	osmo_iofd_free(endp->iofd_rtcp);
	twrtp_jibuf_destroy(endp->twjit);
	talloc_free(endp);
}