Reply to BSC's RESET with RESET ACK directly

Let the BSCNAT directly reply to RESET sent from BSC with RESET ACK.
bssap_ran_handle_reset() is a bit empty right now but will be used in a
future patch to store the BSC.

Related: SYS#5560
Related: https://osmocom.org/projects/osmo-bscnat/wiki/AoIP_OsmoBSCNAT#RESET
Change-Id: I3223409e25c93b625d67634caf68efe9772e2558
This commit is contained in:
Oliver Smith 2022-03-09 16:20:30 +01:00
parent 8ca3a1ad8f
commit d0059e2bd2
5 changed files with 130 additions and 1 deletions

View File

@ -1,6 +1,7 @@
noinst_HEADERS = \
bsc_nat.h \
bsc_nat_fsm.h \
bssap.h \
logging.h \
vty.h \
$(NULL)

View File

@ -0,0 +1,25 @@
/* (C) 2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* Author: Oliver Smith <osmith@sysmocom.de>
* 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 Affero 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/lienses/>.
*
*/
#pragma once
#include <osmocom/bsc_nat/bsc_nat.h>
int bssap_handle_udt(struct bsc_nat_sccp_inst *sccp_inst, struct osmo_sccp_addr *addr, struct msgb *msgb,
unsigned int length);

View File

@ -27,6 +27,7 @@ bin_PROGRAMS = \
osmo_bsc_nat_SOURCES = \
bsc_nat.c \
bsc_nat_fsm.c \
bssap.c \
logging.c \
main.c \
vty.c \

View File

@ -27,6 +27,7 @@
#include <osmocom/sigtran/sccp_helpers.h>
#include <osmocom/bsc_nat/bsc_nat.h>
#include <osmocom/bsc_nat/bsc_nat_fsm.h>
#include <osmocom/bsc_nat/bssap.h>
#include <osmocom/bsc_nat/logging.h>
#define DEFAULT_PC_RAN "0.23.1" /* same as default for OsmoMSC */
@ -299,6 +300,10 @@ static int sccp_sap_up_ran(struct osmo_prim_hdr *oph, void *scu)
case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
/* connection-less data received */
rc = bssap_handle_udt(sccp_inst, &prim->u.unitdata.calling_addr, oph->msg, msgb_l2len(oph->msg));
/* FIXME: don't forward this to the MSC anymore, as soon as the
* BSCNAT is able to do the RESET to MSC by itself. */
addr = &prim->u.unitdata.calling_addr;
if (sccp_sap_get_peer_addr_out(sccp_inst, addr, &peer_addr_out) < 0)
@ -314,7 +319,6 @@ static int sccp_sap_up_ran(struct osmo_prim_hdr *oph, void *scu)
&peer_addr_out,
oph->msg->data,
msgb_length(oph->msg));
rc = 0;
break;
default:

98
src/osmo-bsc-nat/bssap.c Normal file
View File

@ -0,0 +1,98 @@
/* (C) 2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* Author: Oliver Smith <osmith@sysmocom.de>
* 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 Affero 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/lienses/>.
*
*/
#include "config.h"
#include <osmocom/core/msgb.h>
#include <osmocom/gsm/gsm0808.h>
#include <osmocom/sigtran/sccp_helpers.h>
#include <osmocom/sigtran/sccp_sap.h>
#include <osmocom/bsc_nat/bsc_nat.h>
#include <osmocom/bsc_nat/logging.h>
static int bssap_ran_handle_reset(struct osmo_sccp_addr *addr, struct msgb *msg, unsigned int length)
{
struct bsc_nat_sccp_inst *sccp_inst = g_bsc_nat->ran;
LOGP(DMAIN, LOGL_NOTICE, "Rx RESET from %s\n", bsc_nat_print_addr(sccp_inst, addr));
LOGP(DMAIN, LOGL_NOTICE, "Tx RESET ACK to %s\n", bsc_nat_print_addr(sccp_inst, addr));
msg = gsm0808_create_reset_ack();
return osmo_sccp_tx_unitdata_msg(sccp_inst->scu, &sccp_inst->addr, addr, msg);
}
static int bssap_ran_rcvmsg_udt(struct osmo_sccp_addr *addr, struct msgb *msg, unsigned int length)
{
int ret = 0;
switch (msg->l3h[0]) {
case BSS_MAP_MSG_RESET:
ret = bssap_ran_handle_reset(addr, msg, length);
break;
default:
LOGP(DMAIN, LOGL_NOTICE, "Unimplemented BSSMAP UDT %s\n", gsm0808_bssap_name(msg->l3h[0]));
break;
}
return ret;
}
static int bssap_rcvmsg_udt(struct bsc_nat_sccp_inst *sccp_inst, struct osmo_sccp_addr *addr, struct msgb *msg,
unsigned int length)
{
if (length < 1) {
LOGP(DMAIN, LOGL_ERROR, "Not enough room: %u\n", length);
return -1;
}
LOGP(DMAIN, LOGL_NOTICE, "Rx UDT BSSMAP %s\n", gsm0808_bssap_name(msg->l3h[0]));
/* NOTE: bssap_cn_rcvmsg_udt() will be added in a future patch */
return bssap_ran_rcvmsg_udt(addr, msg, length);
}
int bssap_handle_udt(struct bsc_nat_sccp_inst *sccp_inst, struct osmo_sccp_addr *addr, struct msgb *msgb,
unsigned int length)
{
struct bssmap_header *bs;
int rc = -1;
LOGP(DMAIN, LOGL_DEBUG, "Rx UDT: %s\n", osmo_hexdump(msgb->l2h, length));
if (length < sizeof(*bs)) {
LOGP(DMAIN, LOGL_ERROR, "The header is too short\n");
return -1;
}
bs = (struct bssmap_header *)msgb->l2h;
if (bs->length < length - sizeof(*bs)) {
LOGP(DMAIN, LOGL_ERROR, "Failed to parse BSSMAP header\n");
return -1;
}
switch (bs->type) {
case BSSAP_MSG_BSS_MANAGEMENT:
msgb->l3h = &msgb->l2h[sizeof(*bs)];
rc = bssap_rcvmsg_udt(sccp_inst, addr, msgb, length - sizeof(*bs));
break;
default:
LOGP(DMAIN, LOGL_NOTICE, "Unimplemented msg type: %s\n", gsm0808_bssap_name(bs->type));
}
return rc;
}