--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/librtpalloc/rtp_alloc_simple.c	Sat Mar 11 23:48:14 2023 -0800
@@ -0,0 +1,124 @@
+/*
+ * The library function implemented in this C module provides a
+ * simple interface for obtaining a single RTP endpoint from
+ * themwi-rtp-mgr.
+ */
+
+#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 "../include/tmgw_const.h"
+#include "../include/rtp_alloc.h"
+#include "rtpmgr_resp.h"
+#include "rtp_alloc_simple.h"
+
+static char ctrl_socket_pathname[] = "/var/gsm/rtp_alloc_socket";
+
+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]);
+}
+
+rtp_alloc_simple(ep_type, out)
+	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 TMGW_EP_TYPE_GSM_ONLY:
+	case TMGW_EP_TYPE_PSTN_ONLY:
+		expect_num_fd = 2;
+		break;
+	case TMGW_EP_TYPE_GATEWAY:
+		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 TMGW_EP_TYPE_GSM_ONLY:
+		out->gsm_rtp_fd = resp.fd_buf[0];
+		out->gsm_rtcp_fd = resp.fd_buf[1];
+		break;
+	case TMGW_EP_TYPE_PSTN_ONLY:
+		out->pstn_rtp_fd = resp.fd_buf[0];
+		out->pstn_rtcp_fd = resp.fd_buf[1];
+		break;
+	case TMGW_EP_TYPE_GATEWAY:
+		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);
+}