Neels Hofmeyr | 7299215 | 2020-09-19 02:36:08 +0200 | [diff] [blame^] | 1 | /* SMLC Lb connection implementation */ |
| 2 | |
| 3 | /* |
| 4 | * (C) 2020 by sysmocom s.m.f.c. <info@sysmocom.de> |
| 5 | * All Rights Reserved |
| 6 | * |
| 7 | * Author: Neels Hofmeyr |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU Affero General Public License as published by |
| 11 | * the Free Software Foundation; either version 3 of the License, or |
| 12 | * (at your option) any later version. |
| 13 | * |
| 14 | * This program is distributed in the hope that it will be useful, |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | * GNU Affero General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU Affero General Public License |
| 20 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 21 | * |
| 22 | */ |
| 23 | |
| 24 | #include <errno.h> |
| 25 | |
| 26 | #include <osmocom/core/logging.h> |
| 27 | #include <osmocom/core/fsm.h> |
| 28 | #include <osmocom/core/signal.h> |
| 29 | #include <osmocom/gsm/bssmap_le.h> |
| 30 | |
| 31 | #include <osmocom/smlc/debug.h> |
| 32 | #include <osmocom/smlc/smlc_data.h> |
| 33 | #include <osmocom/smlc/sccp_lb_inst.h> |
| 34 | #include <osmocom/smlc/lb_peer.h> |
| 35 | #include <osmocom/smlc/lb_conn.h> |
| 36 | #include <osmocom/smlc/smlc_loc_req.h> |
| 37 | |
| 38 | static int lb_conn_use_cb(struct osmo_use_count_entry *e, int32_t old_use_count, const char *file, int line) |
| 39 | { |
| 40 | struct lb_conn *lb_conn = e->use_count->talloc_object; |
| 41 | int32_t total; |
| 42 | int level; |
| 43 | |
| 44 | if (!e->use) |
| 45 | return -EINVAL; |
| 46 | |
| 47 | total = osmo_use_count_total(&lb_conn->use_count); |
| 48 | |
| 49 | if (total == 0 |
| 50 | || (total == 1 && old_use_count == 0 && e->count == 1)) |
| 51 | level = LOGL_INFO; |
| 52 | else |
| 53 | level = LOGL_DEBUG; |
| 54 | |
| 55 | LOG_LB_CONN_SL(lb_conn, DREF, level, file, line, "%s %s: now used by %s\n", |
| 56 | (e->count - old_use_count) > 0? "+" : "-", e->use, |
| 57 | osmo_use_count_to_str_c(OTC_SELECT, &lb_conn->use_count)); |
| 58 | |
| 59 | if (e->count < 0) |
| 60 | return -ERANGE; |
| 61 | |
| 62 | if (total == 0) |
| 63 | lb_conn_close(lb_conn); |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | static struct lb_conn *lb_conn_alloc(struct lb_peer *lb_peer, uint32_t sccp_conn_id, const char *use_token) |
| 68 | { |
| 69 | struct lb_conn *lb_conn; |
| 70 | |
| 71 | lb_conn = talloc(lb_peer, struct lb_conn); |
| 72 | OSMO_ASSERT(lb_conn); |
| 73 | |
| 74 | *lb_conn = (struct lb_conn){ |
| 75 | .lb_peer = lb_peer, |
| 76 | .sccp_conn_id = sccp_conn_id, |
| 77 | .use_count = { |
| 78 | .talloc_object = lb_conn, |
| 79 | .use_cb = lb_conn_use_cb, |
| 80 | }, |
| 81 | }; |
| 82 | |
| 83 | llist_add(&lb_conn->entry, &lb_peer->sli->lb_conns); |
| 84 | lb_conn_get(lb_conn, use_token); |
| 85 | return lb_conn; |
| 86 | } |
| 87 | |
| 88 | struct lb_conn *lb_conn_create_incoming(struct lb_peer *lb_peer, uint32_t sccp_conn_id, const char *use_token) |
| 89 | { |
| 90 | LOG_LB_PEER(lb_peer, LOGL_DEBUG, "Incoming lb_conn id: %u\n", sccp_conn_id); |
| 91 | return lb_conn_alloc(lb_peer, sccp_conn_id, use_token); |
| 92 | } |
| 93 | |
| 94 | struct lb_conn *lb_conn_create_outgoing(struct lb_peer *lb_peer, const char *use_token) |
| 95 | { |
| 96 | int new_conn_id = sccp_lb_inst_next_conn_id(); |
| 97 | if (new_conn_id < 0) |
| 98 | return NULL; |
| 99 | LOG_LB_PEER(lb_peer, LOGL_DEBUG, "Outgoing lb_conn id: %u\n", new_conn_id); |
| 100 | return lb_conn_alloc(lb_peer, new_conn_id, use_token); |
| 101 | } |
| 102 | |
| 103 | struct lb_conn *lb_conn_find_by_smlc_subscr(struct smlc_subscr *smlc_subscr, const char *use_token) |
| 104 | { |
| 105 | struct lb_conn *lb_conn; |
| 106 | llist_for_each_entry(lb_conn, &g_smlc->lb->lb_conns, entry) { |
| 107 | if (lb_conn->smlc_subscr == smlc_subscr) { |
| 108 | lb_conn_get(lb_conn, use_token); |
| 109 | return lb_conn; |
| 110 | } |
| 111 | } |
| 112 | return NULL; |
| 113 | } |
| 114 | |
| 115 | int lb_conn_down_l2_co(struct lb_conn *lb_conn, struct msgb *l3, bool initial) |
| 116 | { |
| 117 | struct lb_peer_ev_ctx co = { |
| 118 | .conn_id = lb_conn->sccp_conn_id, |
| 119 | .lb_conn = lb_conn, |
| 120 | .msg = l3, |
| 121 | }; |
| 122 | if (!lb_conn->lb_peer) |
| 123 | return -EIO; |
| 124 | return osmo_fsm_inst_dispatch(lb_conn->lb_peer->fi, |
| 125 | initial ? LB_PEER_EV_MSG_DOWN_CO_INITIAL : LB_PEER_EV_MSG_DOWN_CO, |
| 126 | &co); |
| 127 | } |
| 128 | |
| 129 | int lb_conn_rx(struct lb_conn *lb_conn, struct msgb *msg, bool initial) |
| 130 | { |
| 131 | struct bssap_le_pdu bssap_le; |
| 132 | struct osmo_bssap_le_err *err; |
| 133 | if (osmo_bssap_le_dec(&bssap_le, &err, msg, msg)) { |
| 134 | LOG_LB_CONN(lb_conn, LOGL_ERROR, "Rx BSSAP-LE with error: %s\n", err->logmsg); |
| 135 | return -EINVAL; |
| 136 | } |
| 137 | |
| 138 | return smlc_loc_req_rx_bssap_le(lb_conn, &bssap_le); |
| 139 | } |
| 140 | |
| 141 | int lb_conn_send_bssmap_le(struct lb_conn *lb_conn, const struct bssmap_le_pdu *bssmap_le) |
| 142 | { |
| 143 | struct msgb *msg; |
| 144 | int rc; |
| 145 | struct bssap_le_pdu bssap_le = { |
| 146 | .discr = BSSAP_LE_MSG_DISCR_BSSMAP_LE, |
| 147 | .bssmap_le = *bssmap_le, |
| 148 | }; |
| 149 | |
| 150 | msg = osmo_bssap_le_enc(&bssap_le); |
| 151 | if (!msg) { |
| 152 | LOG_LB_CONN(lb_conn, LOGL_ERROR, "Unable to encode %s\n", |
| 153 | osmo_bssap_le_pdu_to_str_c(OTC_SELECT, &bssap_le)); |
| 154 | return -EINVAL; |
| 155 | } |
| 156 | rc = lb_conn_down_l2_co(lb_conn, msg, false); |
| 157 | msgb_free(msg); |
| 158 | if (rc) |
| 159 | LOG_LB_CONN(lb_conn, LOGL_ERROR, "Unable to send %s\n", |
| 160 | osmo_bssap_le_pdu_to_str_c(OTC_SELECT, &bssap_le)); |
| 161 | return rc; |
| 162 | } |
| 163 | |
| 164 | /* Regularly close the lb_conn */ |
| 165 | void lb_conn_close(struct lb_conn *lb_conn) |
| 166 | { |
| 167 | if (!lb_conn) |
| 168 | return; |
| 169 | if (lb_conn->closing) |
| 170 | return; |
| 171 | lb_conn->closing = true; |
| 172 | LOG_LB_PEER(lb_conn->lb_peer, LOGL_DEBUG, "Closing lb_conn\n"); |
| 173 | |
| 174 | if (lb_conn->lb_peer) { |
| 175 | /* Todo: pass a useful SCCP cause? */ |
| 176 | sccp_lb_disconnect(lb_conn->lb_peer->sli, lb_conn->sccp_conn_id, 0); |
| 177 | lb_conn->lb_peer = NULL; |
| 178 | } |
| 179 | |
| 180 | if (lb_conn->smlc_loc_req) |
| 181 | osmo_fsm_inst_term(lb_conn->smlc_loc_req->fi, OSMO_FSM_TERM_REGULAR, NULL); |
| 182 | |
| 183 | if (lb_conn->smlc_subscr) |
| 184 | smlc_subscr_put(lb_conn->smlc_subscr, SMLC_SUBSCR_USE_LB_CONN); |
| 185 | |
| 186 | llist_del(&lb_conn->entry); |
| 187 | talloc_free(lb_conn); |
| 188 | } |
| 189 | |
| 190 | /* Same as lb_conn_close() but without sending any SCCP messages (e.g. after RESET) */ |
| 191 | void lb_conn_discard(struct lb_conn *lb_conn) |
| 192 | { |
| 193 | if (!lb_conn) |
| 194 | return; |
| 195 | /* Make sure to drop dead and don't dispatch things like DISCONNECT requests on SCCP. */ |
| 196 | lb_conn->lb_peer = NULL; |
| 197 | lb_conn_close(lb_conn); |
| 198 | } |