sysmobts: Begin with an OML router that will be used by the manager

Begin with the basics of a OML Router. This is currently only
capable of accepting a connection and read messages but it will
evolve into a router in multiple stages. The first usage will
be by the sysmobts-mgr. An OML Error Indication will be sent by
the sysmobts-mgr and it will be forwarded to the BSC. In the
second step we will set a relative power reduction from the
sysmobts-mgr.

In the long-term this code will be used to communicate with a
second TRX.

src/osmo-bts-sysmo/Makefile.am

@@ -4,12 +4,12 @@ COMMON_LDADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOS
 
 EXTRA_DIST = misc/sysmobts_mgr.h misc/sysmobts_misc.h misc/sysmobts_par.h \
 	misc/sysmobts_eeprom.h misc/sysmobts_nl.h femtobts.h hw_misc.h \
-	l1_fwd.h l1_if.h l1_transp.h eeprom.h utils.h
+	l1_fwd.h l1_if.h l1_transp.h eeprom.h utils.h oml_router.h
 
 bin_PROGRAMS = sysmobts sysmobts-remote l1fwd-proxy sysmobts-mgr sysmobts-util
 
 COMMON_SOURCES = main.c femtobts.c l1_if.c oml.c sysmobts_vty.c tch.c hw_misc.c calib_file.c \
-		 eeprom.c calib_fixup.c utils.c misc/sysmobts_par.c
+		 eeprom.c calib_fixup.c utils.c misc/sysmobts_par.c oml_router.c
 
 sysmobts_SOURCES = $(COMMON_SOURCES) l1_transp_hw.c
 sysmobts_LDADD = $(top_builddir)/src/common/libbts.a $(COMMON_LDADD)

src/osmo-bts-sysmo/main.c

@@ -52,6 +52,7 @@
 #include "eeprom.h"
 #include "l1_if.h"
 #include "hw_misc.h"
+#include "oml_router.h"
 
 /* FIXME: read from real hardware */
 const uint8_t abis_mac[6] = { 0,1,2,3,4,5 };
@@ -300,6 +301,7 @@ int main(int argc, char **argv)
 	struct gsm_bts_role_bts *btsb;
 	struct e1inp_line *line;
 	void *tall_msgb_ctx;
+	struct osmo_fd accept_fd, read_fd;
 	int rc;
 
 	tall_bts_ctx = talloc_named_const(NULL, 1, "OsmoBTS context");
@@ -367,6 +369,12 @@ int main(int argc, char **argv)
 	signal(SIGUSR2, &signal_handler);
 	osmo_init_ignore_signals();
 
+	rc = oml_router_init(bts, &accept_fd, &read_fd);
+	if (rc < 0) {
+		perror("Error creating the OML router\n");
+		exit(1);
+	}
+
 	if (!btsb->bsc_oml_host) {
 		fprintf(stderr, "Cannot start BTS without knowing BSC OML IP\n");
 		exit(1);

src/osmo-bts-sysmo/oml_router.c

@@ -0,0 +1,115 @@
+/* Beginnings of an OML router */
+
+/* (C) 2014 by sysmocom s.f.m.c. GmbH
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "oml_router.h"
+
+#include <osmo-bts/bts.h>
+#include <osmo-bts/logging.h>
+#include <osmo-bts/oml.h>
+
+#include <osmocom/core/socket.h>
+#include <osmocom/core/select.h>
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+static int oml_router_read_cb(struct osmo_fd *fd, unsigned int what)
+{
+	struct msgb *msg;
+	int rc;
+
+	msg = oml_msgb_alloc();
+	if (!msg) {
+		LOGP(DL1C, LOGL_ERROR, "Failed to allocate oml msgb.\n");
+		return -1;
+	}
+
+	rc = recv(fd->fd, msg->tail, msg->data_len, 0);
+	if (rc <= 0) {
+		close(fd->fd);
+		osmo_fd_unregister(fd);
+		fd->fd = -1;
+		goto err;
+	}
+
+	msgb_put(msg, rc);
+
+	/* todo analyze and dispatch message */
+
+err:
+	msgb_free(msg);
+	return -1;
+}
+
+static int oml_router_accept_cb(struct osmo_fd *accept_fd, unsigned int what)
+{
+	int fd;
+	struct osmo_fd *read_fd = (struct osmo_fd *) accept_fd->data;
+
+	/* Accept only one connection at a time. De-register it */
+	if (read_fd->fd > -1) {
+		LOGP(DL1C, LOGL_NOTICE,
+			"New OML router connection. Closing old one.\n");
+		close(read_fd->fd);
+		osmo_fd_unregister(read_fd);
+		read_fd->fd = -1;
+	}
+
+	fd = accept(accept_fd->fd, NULL, NULL);
+	if (fd < 0) {
+		LOGP(DL1C, LOGL_ERROR, "Failed to accept. errno: %s.\n",
+		     strerror(errno));
+		return -1;
+	}
+
+	read_fd->fd = fd;
+	if (osmo_fd_register(read_fd) != 0) {
+		LOGP(DL1C, LOGL_ERROR, "Registering the read fd failed.\n");
+		close(fd);
+		read_fd->fd = -1;
+		return -1;
+	}
+
+	return 0;
+}
+
+int oml_router_init(struct gsm_bts *bts,
+			struct osmo_fd *accept_fd, struct osmo_fd *read_fd)
+{
+	int rc;
+
+	memset(accept_fd, 0, sizeof(*accept_fd));
+	memset(read_fd, 0, sizeof(*read_fd));
+
+	accept_fd->cb = oml_router_accept_cb;
+	accept_fd->data = read_fd;
+
+	read_fd->cb = oml_router_read_cb;
+	read_fd->data = bts;
+	read_fd->when = BSC_FD_READ;
+	read_fd->fd = -1;
+
+	rc = osmo_sock_unix_init_ofd(accept_fd, SOCK_SEQPACKET, 0,
+					OML_ROUTER_PATH,
+					OSMO_SOCK_F_BIND | OSMO_SOCK_F_NONBLOCK);
+	return rc;
+}

src/osmo-bts-sysmo/oml_router.h

@@ -0,0 +1,13 @@
+#pragma once
+
+struct gsm_bts;
+struct osmo_fd;
+
+/**
+ * The default path sysmobts will listen for incoming
+ * registrations for OML routing and sending.
+ */
+#define OML_ROUTER_PATH "/var/run/sysmobts/oml_router"
+
+
+int oml_router_init(struct gsm_bts *bts, struct osmo_fd *accept, struct osmo_fd *read);