--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rtp-mgr/ctrl_prot.c	Sat Mar 11 20:19:14 2023 -0800
@@ -0,0 +1,130 @@
+/*
+ * In this module we implement our control socket protocol.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <syslog.h>
+#include <unistd.h>
+#include "../include/tmgw_const.h"
+#include "../include/rtp_alloc.h"
+#include "struct.h"
+#include "select.h"
+
+extern struct bind_range_cfg bind_range_gsm, bind_range_pstn;
+
+void
+free_rtp_end(roe)
+	struct rtp_one_end *roe;
+{
+	close(roe->rtp_fd);
+	close(roe->rtcp_fd);
+}
+
+void
+ctrl_message_handler(fd)
+{
+	struct rtp_alloc_req req;
+	struct rtp_alloc_resp resp;
+	struct rtp_one_end rtp_gsm, rtp_pstn;
+	struct iovec iov;
+	struct msghdr msg;
+	int fd_out[4], num_fd, *fd_bufptr;
+	union {
+		char buf[CMSG_SPACE(sizeof fd_out)];
+		struct cmsghdr align;
+	} cmsgu;
+	struct cmsghdr *cmsg;
+	int rc;
+
+	/* receive request */
+	rc = recv(fd, &req, sizeof req, 0);
+	if (rc < sizeof req) {
+		syslog(LOG_DEBUG, "ctrl connection closing");
+		close(fd);
+		FD_CLR(fd, &select_for_read);
+		return;
+	}
+	/* start preparing response */
+	bzero(&resp, sizeof resp);
+	resp.transact_ref = req.transact_ref;
+	switch (req.ep_type) {
+	case TMGW_EP_TYPE_DUMMY_GSM:
+	case TMGW_EP_TYPE_DUMMY_PSTN:
+	case TMGW_EP_TYPE_GATEWAY:
+		break;
+	default:
+		resp.res = RTP_ALLOC_ERR_PARAM;
+error_resp:	send(fd, &resp, sizeof resp, 0);
+		return;
+	}
+	/* allocate resources */
+	if (req.ep_type & TMGW_EP_HAS_GSM_SOCK) {
+		rc = get_rtp_port_pair(&rtp_gsm, &bind_range_gsm);
+		if (rc < 0) {
+			syslog(LOG_ERR,
+				"unable to get local port pair on GSM side");
+			resp.res = RTP_ALLOC_ERR_RSRC;
+			goto error_resp;
+		}
+	}
+	if (req.ep_type & TMGW_EP_HAS_PSTN_SOCK) {
+		rc = get_rtp_port_pair(&rtp_pstn, &bind_range_pstn);
+		if (rc < 0) {
+			syslog(LOG_ERR,
+				"unable to get local port pair on PSTN side");
+			if (req.ep_type & TMGW_EP_HAS_GSM_SOCK)
+				free_rtp_end(&rtp_gsm);
+			resp.res = RTP_ALLOC_ERR_RSRC;
+			goto error_resp;
+		}
+	}
+	/* finish ordinary body of response */
+	resp.res = RTP_ALLOC_OK;
+	if (req.ep_type & TMGW_EP_HAS_GSM_SOCK)
+		bcopy(&rtp_gsm.bound_addr, &resp.gsm_addr,
+			sizeof(struct sockaddr_in));
+	if (req.ep_type & TMGW_EP_HAS_PSTN_SOCK)
+		bcopy(&rtp_pstn.bound_addr, &resp.pstn_addr,
+			sizeof(struct sockaddr_in));
+	iov.iov_base = &resp;
+	iov.iov_len = sizeof resp;
+	/* file descriptor passing voodoo */
+	switch (req.ep_type) {
+	case TMGW_EP_TYPE_DUMMY_GSM:
+		num_fd = 2;
+		fd_out[0] = rtp_gsm.rtp_fd;
+		fd_out[1] = rtp_gsm.rtcp_fd;
+		break;
+	case TMGW_EP_TYPE_DUMMY_PSTN:
+		num_fd = 2;
+		fd_out[0] = rtp_pstn.rtp_fd;
+		fd_out[1] = rtp_pstn.rtcp_fd;
+		break;
+	case TMGW_EP_TYPE_GATEWAY:
+		num_fd = 4;
+		fd_out[0] = rtp_gsm.rtp_fd;
+		fd_out[1] = rtp_gsm.rtcp_fd;
+		fd_out[2] = rtp_pstn.rtp_fd;
+		fd_out[3] = rtp_pstn.rtcp_fd;
+	}
+	bzero(&msg, sizeof msg);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	msg.msg_control = cmsgu.buf;
+	msg.msg_controllen = CMSG_SPACE(sizeof(int) * num_fd);
+	cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(int) * num_fd);
+	fd_bufptr = (int *) CMSG_DATA(cmsg);
+	bcopy(fd_out, fd_bufptr, sizeof(int) * num_fd);
+	sendmsg(fd, &msg, 0);
+}