138 lines
4.3 KiB
C
138 lines
4.3 KiB
C
/* Generic SCCP handling across all OsmoBSC users */
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/*
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* (C) 2020 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
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*
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* All Rights Reserved
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*
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* Author: Neels Hofmeyr <neels@hofmeyr.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <osmocom/core/utils.h>
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#include <osmocom/bsc/gsm_data.h>
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#include <osmocom/bsc/bsc_msc_data.h>
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#include <osmocom/bsc/lb.h>
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struct bsc_sccp_inst *bsc_sccp_inst_alloc(void *ctx)
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{
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struct bsc_sccp_inst *bsc_sccp;
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bsc_sccp = talloc_zero(ctx, struct bsc_sccp_inst);
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OSMO_ASSERT(bsc_sccp);
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bsc_sccp->next_id = 1;
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return bsc_sccp;
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}
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int bsc_sccp_inst_register_gscon(struct bsc_sccp_inst *bsc_sccp, struct gsm_subscriber_connection *conn)
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{
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struct rb_node **n = &(bsc_sccp->connections.rb_node);
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struct rb_node *parent = NULL;
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uint32_t conn_id = conn->sccp.conn_id;
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OSMO_ASSERT(conn_id != SCCP_CONN_ID_UNSET);
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while (*n) {
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struct gsm_subscriber_connection *it;
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it = container_of(*n, struct gsm_subscriber_connection, sccp.node);
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parent = *n;
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if (conn_id < it->sccp.conn_id) {
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n = &((*n)->rb_left);
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} else if (conn_id > it->sccp.conn_id) {
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n = &((*n)->rb_right);
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} else {
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LOGP(DMSC, LOGL_ERROR,
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"Trying to reserve already reserved conn_id %u\n", conn_id);
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return -EEXIST;
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}
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}
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rb_link_node(&conn->sccp.node, parent, n);
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rb_insert_color(&conn->sccp.node, &bsc_sccp->connections);
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return 0;
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}
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void bsc_sccp_inst_unregister_gscon(struct bsc_sccp_inst *bsc_sccp, struct gsm_subscriber_connection *conn)
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{
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OSMO_ASSERT(conn->sccp.conn_id != SCCP_CONN_ID_UNSET);
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rb_erase(&conn->sccp.node, &bsc_sccp->connections);
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}
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/* Helper function to Check if the given connection id is already assigned */
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struct gsm_subscriber_connection *bsc_sccp_inst_get_gscon_by_conn_id(const struct bsc_sccp_inst *bsc_sccp, uint32_t conn_id)
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{
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const struct rb_node *node = bsc_sccp->connections.rb_node;
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struct gsm_subscriber_connection *conn;
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OSMO_ASSERT(conn_id != SCCP_CONN_ID_UNSET);
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/* Range (0..SCCP_CONN_ID_MAX) expected, see bsc_sccp_inst_next_conn_id() */
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OSMO_ASSERT(conn_id <= SCCP_CONN_ID_MAX);
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while (node) {
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conn = container_of(node, struct gsm_subscriber_connection, sccp.node);
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if (conn_id < conn->sccp.conn_id)
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node = node->rb_left;
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else if (conn_id > conn->sccp.conn_id)
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node = node->rb_right;
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else
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return conn;
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}
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return NULL;
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}
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/* We need an unused SCCP conn_id across all SCCP users. */
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uint32_t bsc_sccp_inst_next_conn_id(struct bsc_sccp_inst *bsc_sccp)
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{
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uint32_t first_id, test_id;
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first_id = test_id = bsc_sccp->next_id;
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/* SUA: RFC3868 sec 3.10.4:
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* The source reference number is a 4 octet long integer.
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* This is allocated by the source SUA instance.
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* M3UA/SCCP: ITU-T Q.713 sec 3.3:
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* The "source local reference" parameter field is a three-octet field containing a
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* reference number which is generated and used by the local node to identify the
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* connection section after the connection section is set up.
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* The coding "all ones" is reserved for future use.
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*Hence, as we currently use the connection ID also as local reference,
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*let's simply use 24 bit ids to fit all link types (excluding 0x00ffffff).
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*/
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while (bsc_sccp_inst_get_gscon_by_conn_id(bsc_sccp, test_id)) {
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/* Optimized modulo operation (% SCCP_CONN_ID_MAX) using bitwise AND plus CMP: */
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test_id = (test_id + 1) & 0x00FFFFFF;
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if (OSMO_UNLIKELY(test_id == 0x00FFFFFF))
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test_id = 0;
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/* Did a whole loop, all used, fail */
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if (OSMO_UNLIKELY(test_id == first_id))
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return SCCP_CONN_ID_UNSET;
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}
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bsc_sccp->next_id = test_id;
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/* Optimized modulo operation (% SCCP_CONN_ID_MAX) using bitwise AND plus CMP: */
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bsc_sccp->next_id = (bsc_sccp->next_id + 1) & 0x00FFFFFF;
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if (OSMO_UNLIKELY(bsc_sccp->next_id == 0x00FFFFFF))
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bsc_sccp->next_id = 0;
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return test_id;
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}
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