Mychaela N. Falconia | ff7c7ea | 2023-09-21 01:55:51 +0000 | [diff] [blame] | 1 | /* OsmoHLR SMS-over-GSUP routing implementation */ |
| 2 | |
| 3 | /* Author: Mychaela N. Falconia <falcon@freecalypso.org>, 2023 - however, |
| 4 | * Mother Mychaela's contributions are NOT subject to copyright. |
| 5 | * No rights reserved, all rights relinquished. |
| 6 | * |
| 7 | * Based on earlier unmerged work by Vadim Yanitskiy, 2019. |
| 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 | #include <stdint.h> |
| 24 | #include <string.h> |
| 25 | #include <errno.h> |
| 26 | |
| 27 | #include <osmocom/core/talloc.h> |
| 28 | #include <osmocom/gsm/gsup.h> |
Mychaela N. Falconia | 786ec5b | 2023-09-19 17:15:43 +0000 | [diff] [blame^] | 29 | #include <osmocom/gsm/gsm48_ie.h> |
| 30 | #include <osmocom/gsm/protocol/gsm_04_11.h> |
Mychaela N. Falconia | ff7c7ea | 2023-09-21 01:55:51 +0000 | [diff] [blame] | 31 | |
| 32 | #include <osmocom/hlr/hlr.h> |
| 33 | #include <osmocom/hlr/hlr_sms.h> |
| 34 | #include <osmocom/hlr/gsup_server.h> |
| 35 | #include <osmocom/hlr/gsup_router.h> |
| 36 | #include <osmocom/hlr/logging.h> |
| 37 | #include <osmocom/hlr/db.h> |
| 38 | |
| 39 | /*********************************************************************** |
| 40 | * core data structures expressing config from VTY |
| 41 | ***********************************************************************/ |
| 42 | |
| 43 | struct hlr_smsc *smsc_find(struct hlr *hlr, const char *name) |
| 44 | { |
| 45 | struct hlr_smsc *smsc; |
| 46 | |
| 47 | llist_for_each_entry(smsc, &hlr->smsc_list, list) { |
| 48 | if (!strcmp(smsc->name, name)) |
| 49 | return smsc; |
| 50 | } |
| 51 | return NULL; |
| 52 | } |
| 53 | |
| 54 | struct hlr_smsc *smsc_alloc(struct hlr *hlr, const char *name) |
| 55 | { |
| 56 | struct hlr_smsc *smsc = smsc_find(hlr, name); |
| 57 | if (smsc) |
| 58 | return NULL; |
| 59 | |
| 60 | smsc = talloc_zero(hlr, struct hlr_smsc); |
| 61 | smsc->name = talloc_strdup(smsc, name); |
| 62 | smsc->hlr = hlr; |
| 63 | llist_add_tail(&smsc->list, &hlr->smsc_list); |
| 64 | |
| 65 | return smsc; |
| 66 | } |
| 67 | |
| 68 | void smsc_free(struct hlr_smsc *smsc) |
| 69 | { |
| 70 | llist_del(&smsc->list); |
| 71 | talloc_free(smsc); |
| 72 | } |
| 73 | |
| 74 | struct hlr_smsc_route *smsc_route_find(struct hlr *hlr, const char *num_addr) |
| 75 | { |
| 76 | struct hlr_smsc_route *rt; |
| 77 | |
| 78 | llist_for_each_entry(rt, &hlr->smsc_routes, list) { |
| 79 | if (!strcmp(rt->num_addr, num_addr)) |
| 80 | return rt; |
| 81 | } |
| 82 | return NULL; |
| 83 | } |
| 84 | |
| 85 | struct hlr_smsc_route *smsc_route_alloc(struct hlr *hlr, const char *num_addr, |
| 86 | struct hlr_smsc *smsc) |
| 87 | { |
| 88 | struct hlr_smsc_route *rt; |
| 89 | |
| 90 | if (smsc_route_find(hlr, num_addr)) |
| 91 | return NULL; |
| 92 | |
| 93 | rt = talloc_zero(hlr, struct hlr_smsc_route); |
| 94 | rt->num_addr = talloc_strdup(rt, num_addr); |
| 95 | rt->smsc = smsc; |
| 96 | llist_add_tail(&rt->list, &hlr->smsc_routes); |
| 97 | |
| 98 | return rt; |
| 99 | } |
| 100 | |
| 101 | void smsc_route_free(struct hlr_smsc_route *rt) |
| 102 | { |
| 103 | llist_del(&rt->list); |
| 104 | talloc_free(rt); |
| 105 | } |
Mychaela N. Falconia | 786ec5b | 2023-09-19 17:15:43 +0000 | [diff] [blame^] | 106 | |
| 107 | /*********************************************************************** |
| 108 | * forwarding of MO SMS to SMSCs based on SM-RP-DA |
| 109 | ***********************************************************************/ |
| 110 | |
| 111 | static const struct hlr_smsc *find_smsc_route(const char *smsc_addr) |
| 112 | { |
| 113 | const struct hlr_smsc_route *rt; |
| 114 | |
| 115 | rt = smsc_route_find(g_hlr, smsc_addr); |
| 116 | if (rt) |
| 117 | return rt->smsc; |
| 118 | return g_hlr->smsc_default; |
| 119 | } |
| 120 | |
| 121 | static void respond_with_sm_rp_cause(struct osmo_gsup_req *req, |
| 122 | uint8_t sm_rp_cause) |
| 123 | { |
| 124 | struct osmo_gsup_message rsp_msg = { }; |
| 125 | |
| 126 | rsp_msg.sm_rp_cause = &sm_rp_cause; |
| 127 | osmo_gsup_req_respond(req, &rsp_msg, true, true); |
| 128 | } |
| 129 | |
| 130 | /* Short Message from MSC/VLR towards SMSC */ |
| 131 | void forward_mo_sms(struct osmo_gsup_req *req) |
| 132 | { |
| 133 | uint8_t gsm48_decode_buffer[GSM411_SMSC_ADDR_MAX_OCTETS]; |
| 134 | char smsc_addr[GSM411_SMSC_ADDR_MAX_DIGITS+1]; |
| 135 | const struct hlr_smsc *smsc; |
| 136 | struct osmo_cni_peer_id dest_peer; |
| 137 | |
| 138 | /* Make sure SM-RP-DA (SMSC address) is present */ |
| 139 | if (req->gsup.sm_rp_da == NULL || !req->gsup.sm_rp_da_len) { |
| 140 | osmo_gsup_req_respond_err(req, GMM_CAUSE_INV_MAND_INFO, |
| 141 | "missing SM-RP-DA"); |
| 142 | return; |
| 143 | } |
| 144 | |
| 145 | if (req->gsup.sm_rp_da_type != OSMO_GSUP_SMS_SM_RP_ODA_SMSC_ADDR) { |
| 146 | osmo_gsup_req_respond_err(req, GMM_CAUSE_INV_MAND_INFO, |
| 147 | "SM-RP-DA type is not SMSC"); |
| 148 | return; |
| 149 | } |
| 150 | |
| 151 | /* Enforce the length constrainst on SM-RP-DA, as specified in |
| 152 | * GSM 04.11 section 8.2.5.2. Also enforce absence of ToN/NPI |
| 153 | * extension octets at the same time. */ |
| 154 | if (req->gsup.sm_rp_da_len < GSM411_SMSC_ADDR_MIN_OCTETS || |
| 155 | req->gsup.sm_rp_da_len > GSM411_SMSC_ADDR_MAX_OCTETS || |
| 156 | !(req->gsup.sm_rp_da[0] & 0x80)) { |
| 157 | /* This form of bogosity originates from the MS, |
| 158 | * not from OsmoMSC or any other Osmocom network elements! */ |
| 159 | LOGP(DLSMS, LOGL_NOTICE, |
| 160 | "Rx '%s' (IMSI-%s) contains invalid SM-RP-DA from MS\n", |
| 161 | osmo_gsup_message_type_name(req->gsup.message_type), |
| 162 | req->gsup.imsi); |
| 163 | respond_with_sm_rp_cause(req, GSM411_RP_CAUSE_SEMANT_INC_MSG); |
| 164 | return; |
| 165 | } |
| 166 | |
| 167 | /* Decode SMSC address from SM-RP-DA */ |
| 168 | gsm48_decode_buffer[0] = req->gsup.sm_rp_da_len - 1; |
| 169 | memcpy(gsm48_decode_buffer + 1, req->gsup.sm_rp_da + 1, |
| 170 | req->gsup.sm_rp_da_len - 1); |
| 171 | gsm48_decode_bcd_number2(smsc_addr, sizeof(smsc_addr), |
| 172 | gsm48_decode_buffer, |
| 173 | req->gsup.sm_rp_da_len, 0); |
| 174 | |
| 175 | /* Look for a route to this SMSC */ |
| 176 | smsc = find_smsc_route(smsc_addr); |
| 177 | if (smsc == NULL) { |
| 178 | LOGP(DLSMS, LOGL_NOTICE, |
| 179 | "Failed to find a route for '%s' (IMSI-%s, SMSC-Addr-%s)\n", |
| 180 | osmo_gsup_message_type_name(req->gsup.message_type), |
| 181 | req->gsup.imsi, smsc_addr); |
| 182 | respond_with_sm_rp_cause(req, |
| 183 | GSM411_RP_CAUSE_MO_NUM_UNASSIGNED); |
| 184 | return; |
| 185 | } |
| 186 | |
| 187 | /* We got the IPA name of our SMSC - forward the message */ |
| 188 | osmo_cni_peer_id_set(&dest_peer, OSMO_CNI_PEER_ID_IPA_NAME, |
| 189 | (const uint8_t *) smsc->name, |
| 190 | strlen(smsc->name) + 1); |
| 191 | osmo_gsup_forward_to_local_peer(req->cb_data, &dest_peer, req, NULL); |
| 192 | } |