Neels Hofmeyr | a1756f3 | 2016-05-20 21:59:55 +0200 | [diff] [blame] | 1 | /* Code to manage MSC subscriber connections over IuCS interface */ |
| 2 | |
| 3 | /* |
| 4 | * (C) 2016,2017 by sysmocom s.f.m.c. GmbH <info@sysmocom.de> |
| 5 | * |
| 6 | * Author: Neels Hofmeyr <nhofmeyr@sysmocom.de> |
| 7 | * |
| 8 | * All Rights Reserved |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU Affero General Public License as published by |
| 12 | * the Free Software Foundation; either version 3 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU Affero General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU Affero General Public License |
| 21 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 22 | * |
| 23 | */ |
| 24 | |
| 25 | #include <inttypes.h> |
| 26 | |
| 27 | #include <osmocom/core/logging.h> |
| 28 | #include <openbsc/debug.h> |
| 29 | |
| 30 | #include <openbsc/gsm_data.h> |
| 31 | #include <openbsc/iu.h> |
| 32 | #include <openbsc/gsm_subscriber.h> |
| 33 | #include <openbsc/osmo_msc.h> |
| 34 | #include <openbsc/vlr.h> |
| 35 | |
| 36 | /* For A-interface see libbsc/bsc_api.c subscr_con_allocate() */ |
| 37 | static struct gsm_subscriber_connection *subscr_conn_allocate_iu(struct gsm_network *network, |
| 38 | struct ue_conn_ctx *ue, |
| 39 | uint16_t lac) |
| 40 | { |
| 41 | struct gsm_subscriber_connection *conn; |
| 42 | |
| 43 | DEBUGP(DIUCS, "Allocating IuCS subscriber conn: lac %d, link_id %p, conn_id %" PRIx32 "\n", |
| 44 | lac, ue->link, ue->conn_id); |
| 45 | |
| 46 | conn = talloc_zero(network, struct gsm_subscriber_connection); |
| 47 | if (!conn) |
| 48 | return NULL; |
| 49 | |
| 50 | conn->network = network; |
| 51 | conn->via_ran = RAN_UTRAN_IU; |
| 52 | conn->iu.ue_ctx = ue; |
| 53 | conn->iu.ue_ctx->rab_assign_addr_enc = network->iu.rab_assign_addr_enc; |
| 54 | conn->lac = lac; |
| 55 | |
| 56 | llist_add_tail(&conn->entry, &network->subscr_conns); |
| 57 | return conn; |
| 58 | } |
| 59 | |
| 60 | static int same_ue_conn(struct ue_conn_ctx *a, struct ue_conn_ctx *b) |
| 61 | { |
| 62 | if (a == b) |
| 63 | return 1; |
| 64 | return (a->link == b->link) |
| 65 | && (a->conn_id == b->conn_id); |
| 66 | } |
| 67 | |
| 68 | static inline void log_subscribers(struct gsm_network *network) |
| 69 | { |
| 70 | if (!log_check_level(DIUCS, LOGL_DEBUG)) |
| 71 | return; |
| 72 | |
| 73 | struct gsm_subscriber_connection *conn; |
| 74 | int i = 0; |
| 75 | llist_for_each_entry(conn, &network->subscr_conns, entry) { |
| 76 | DEBUGP(DIUCS, "%3d: %s", i, vlr_subscr_name(conn->vsub)); |
| 77 | switch (conn->via_ran) { |
| 78 | case RAN_UTRAN_IU: |
| 79 | DEBUGPC(DIUCS, " Iu"); |
| 80 | if (conn->iu.ue_ctx) { |
| 81 | DEBUGPC(DIUCS, " link %p, conn_id %d", |
| 82 | conn->iu.ue_ctx->link, |
| 83 | conn->iu.ue_ctx->conn_id |
| 84 | ); |
| 85 | } |
| 86 | break; |
| 87 | case RAN_GERAN_A: |
| 88 | DEBUGPC(DIUCS, " A"); |
| 89 | /* TODO log A-interface connection details */ |
| 90 | break; |
| 91 | case RAN_UNKNOWN: |
| 92 | DEBUGPC(DIUCS, " ?"); |
| 93 | break; |
| 94 | default: |
| 95 | DEBUGPC(DIUCS, " invalid"); |
| 96 | break; |
| 97 | } |
| 98 | DEBUGPC(DIUCS, "\n"); |
| 99 | i++; |
| 100 | } |
| 101 | DEBUGP(DIUCS, "subscribers registered: %d\n", i); |
| 102 | } |
| 103 | |
| 104 | /* Return an existing IuCS subscriber connection record for the given link and |
| 105 | * connection IDs, or return NULL if not found. */ |
| 106 | struct gsm_subscriber_connection *subscr_conn_lookup_iu( |
| 107 | struct gsm_network *network, |
| 108 | struct ue_conn_ctx *ue) |
| 109 | { |
| 110 | struct gsm_subscriber_connection *conn; |
| 111 | |
| 112 | DEBUGP(DIUCS, "Looking for IuCS subscriber: link_id %p, conn_id %" PRIx32 "\n", |
| 113 | ue->link, ue->conn_id); |
| 114 | log_subscribers(network); |
| 115 | |
| 116 | llist_for_each_entry(conn, &network->subscr_conns, entry) { |
| 117 | if (conn->via_ran != RAN_UTRAN_IU) |
| 118 | continue; |
| 119 | if (!same_ue_conn(conn->iu.ue_ctx, ue)) |
| 120 | continue; |
| 121 | DEBUGP(DIUCS, "Found IuCS subscriber for link_id %p, conn_id %" PRIx32 "\n", |
| 122 | ue->link, ue->conn_id); |
| 123 | return conn; |
| 124 | } |
| 125 | DEBUGP(DIUCS, "No IuCS subscriber found for link_id %p, conn_id %" PRIx32 "\n", |
| 126 | ue->link, ue->conn_id); |
| 127 | return NULL; |
| 128 | } |
| 129 | |
| 130 | /* Receive MM/CC/... message from IuCS (SCCP user SAP). |
| 131 | * msg->dst must reference a struct ue_conn_ctx, which identifies the peer that |
| 132 | * sent the msg. |
| 133 | * |
| 134 | * For A-interface see libbsc/bsc_api.c gsm0408_rcvmsg(). */ |
| 135 | int gsm0408_rcvmsg_iucs(struct gsm_network *network, struct msgb *msg, |
| 136 | uint16_t *lac) |
| 137 | { |
| 138 | int rc; |
| 139 | struct ue_conn_ctx *ue_ctx; |
| 140 | struct gsm_subscriber_connection *conn; |
| 141 | |
| 142 | ue_ctx = (struct ue_conn_ctx*)msg->dst; |
| 143 | |
| 144 | /* TODO: are there message types that could allow us to skip this |
| 145 | * search? */ |
| 146 | conn = subscr_conn_lookup_iu(network, ue_ctx); |
| 147 | |
| 148 | if (conn && lac && (conn->lac != *lac)) { |
| 149 | LOGP(DIUCS, LOGL_ERROR, "IuCS subscriber has changed LAC" |
| 150 | " within the same connection, discarding connection:" |
| 151 | " %s from LAC %d to %d\n", |
| 152 | vlr_subscr_name(conn->vsub), conn->lac, *lac); |
| 153 | /* Deallocate conn with previous LAC */ |
| 154 | msc_subscr_conn_close(conn, GSM_CAUSE_INV_MAND_INFO); |
| 155 | /* At this point we could be tolerant and allocate a new |
| 156 | * connection, but changing the LAC within the same connection |
| 157 | * is shifty. Rather cancel everything. */ |
| 158 | return -1; |
| 159 | } |
| 160 | |
| 161 | if (conn) { |
| 162 | /* Make sure we don't receive RR over IuCS; otherwise all |
| 163 | * messages handled by gsm0408_dispatch() are of interest (CC, |
| 164 | * MM, SMS, NS_SS, maybe even MM_GPRS and SM_GPRS). */ |
| 165 | struct gsm48_hdr *gh = msgb_l3(msg); |
| 166 | uint8_t pdisc = gh->proto_discr & 0x0f; |
| 167 | OSMO_ASSERT(pdisc != GSM48_PDISC_RR); |
| 168 | |
| 169 | msc_dtap(conn, ue_ctx->conn_id, msg); |
| 170 | rc = 0; |
| 171 | } else { |
| 172 | /* allocate a new connection */ |
| 173 | |
| 174 | if (!lac) { |
| 175 | LOGP(DIUCS, LOGL_ERROR, "New IuCS subscriber" |
| 176 | " but no LAC available. Expecting an InitialUE" |
| 177 | " message containing a LAI IE." |
| 178 | " Dropping connection.\n"); |
| 179 | return -1; |
| 180 | } |
| 181 | |
| 182 | conn = subscr_conn_allocate_iu(network, ue_ctx, *lac); |
| 183 | if (!conn) |
| 184 | abort(); |
| 185 | |
| 186 | /* ownership of conn hereby goes to the MSC: */ |
| 187 | rc = msc_compl_l3(conn, msg, 0); |
| 188 | } |
| 189 | |
| 190 | return rc; |
| 191 | } |