/*
 * The library function implemented in this C module provides a
 * simple interface for obtaining a single RTP endpoint from
 * themwi-rtp-mgr.  This "simple client" option is suitable only
 * for command line utilities, not for daemon processes!
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>

#include <themwi/rtp/rtp_alloc_if.h>
#include <themwi/rtp/rtp_alloc_resp.h>
#include <themwi/rtp/rtp_alloc_simple.h>

static const char ctrl_socket_pathname[] = "/var/gsm/rtp_alloc_socket";

static void
fill_sockaddr_un(pathname, sunp, lenp)
	char *pathname;
	struct sockaddr_un *sunp;
	unsigned *lenp;
{
	/* local socket binding voodoo copied from osmocon */
	sunp->sun_family = AF_UNIX;
	strncpy(sunp->sun_path, pathname, sizeof(sunp->sun_path));
	sunp->sun_path[sizeof(sunp->sun_path) - 1] = '\0';
	/* we use the same magic that X11 uses in Xtranssock.c for
	 * calculating the proper length of the sockaddr */
#if defined(BSD44SOCKETS) || defined(__UNIXWARE__)
	sunp->sun_len = strlen(sunp->sun_path);
#endif
#if defined(BSD44SOCKETS) || defined(SUN_LEN)
	*lenp = SUN_LEN(sunp);
#else
	*lenp = strlen(sunp->sun_path) +
		offsetof(struct sockaddr_un, sun_path) + 1;
#endif
}

static void
close_fds(resp)
	struct rtp_alloc_resp_wrap *resp;
{
	unsigned n;

	for (n = 0; n < resp->num_fd; n++)
		close(resp->fd_buf[n]);
}

int rtp_alloc_simple(int ep_type, struct rtp_alloc_simple *out)
{
	struct sockaddr_un sa;
	unsigned sa_len;
	int ctrl_fd, rc;
	struct rtp_alloc_req req;
	struct rtp_alloc_resp_wrap resp;
	unsigned expect_num_fd;

	switch (ep_type) {
	case RTP_ALLOC_TYPE_GSM:
	case RTP_ALLOC_TYPE_PSTN:
		expect_num_fd = 2;
		break;
	case RTP_ALLOC_TYPE_GSM2PSTN:
	case RTP_ALLOC_TYPE_GSM2GSM:
		expect_num_fd = 4;
		break;
	default:
		fprintf(stderr,
			"rtp_alloc_simple() error: unknown EP type %d\n",
			ep_type);
		return(-1);
	}
	ctrl_fd = socket(AF_UNIX, SOCK_SEQPACKET, 0);
	if (ctrl_fd < 0) {
		perror("socket(AF_UNIX, SOCK_SEQPACKET, 0)");
		return(-1);
	}
	fill_sockaddr_un(ctrl_socket_pathname, &sa, &sa_len);
	rc = connect(ctrl_fd, (struct sockaddr *) &sa, sa_len);
	if (rc < 0) {
		perror(ctrl_socket_pathname);
		close(ctrl_fd);
		return(-1);
	}
	bzero(&req, sizeof req);
	req.ep_type = ep_type;
	rc = send(ctrl_fd, &req, sizeof req, 0);
	if (rc < 0) {
		perror("send to RTP allocator socket");
		close(ctrl_fd);
		return(-1);
	}
	rc = collect_rtpmgr_resp(ctrl_fd, 0, &resp);
	if (rc < 0) {
		perror("recvmsg from RTP allocator socket");
		close(ctrl_fd);
		return(-1);
	}
	close(ctrl_fd);
	if (resp.resp_len != sizeof(struct rtp_alloc_resp)) {
		fprintf(stderr,
"error: response packet from themwi-rtp-mgr has wrong length (%u bytes)\n",
			resp.resp_len);
		close_fds(&resp);
		return(-1);
	}
	if (resp.resp.res != RTP_ALLOC_OK) {
		fprintf(stderr, "themwi-rtp-mgr returned error %u\n",
			resp.resp.res);
		close_fds(&resp);
		return(-1);
	}
	if (resp.num_fd != expect_num_fd) {
		fprintf(stderr,
"error: themwi-rtp-mgr returned %u descriptors instead of expected %u\n",
			resp.num_fd, expect_num_fd);
		close_fds(&resp);
		return(-1);
	}
	switch (ep_type) {
	case RTP_ALLOC_TYPE_GSM:
		out->gsm_rtp_fd = resp.fd_buf[0];
		out->gsm_rtcp_fd = resp.fd_buf[1];
		break;
	case RTP_ALLOC_TYPE_PSTN:
		out->pstn_rtp_fd = resp.fd_buf[0];
		out->pstn_rtcp_fd = resp.fd_buf[1];
		break;
	case RTP_ALLOC_TYPE_GSM2PSTN:
	case RTP_ALLOC_TYPE_GSM2GSM:
		out->gsm_rtp_fd = resp.fd_buf[0];
		out->gsm_rtcp_fd = resp.fd_buf[1];
		out->pstn_rtp_fd = resp.fd_buf[2];
		out->pstn_rtcp_fd = resp.fd_buf[3];
	}
	bcopy(&resp.resp.gsm_addr, &out->gsm_addr,
		sizeof(struct sockaddr_storage));
	bcopy(&resp.resp.pstn_addr, &out->pstn_addr,
		sizeof(struct sockaddr_storage));
	return(0);
}