Neels Hofmeyr | c4628a3 | 2018-12-07 14:47:34 +0100 | [diff] [blame] | 1 | /* Directing individual GSUP messages to their respective handlers. */ |
| 2 | /* |
| 3 | * (C) 2019 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de> |
| 4 | * All Rights Reserved |
| 5 | * |
| 6 | * Author: Neels Hofmeyr |
| 7 | * |
| 8 | * SPDX-License-Identifier: GPL-2.0+ |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 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 General Public License for more details. |
Neels Hofmeyr | c4628a3 | 2018-12-07 14:47:34 +0100 | [diff] [blame] | 19 | */ |
| 20 | #include <errno.h> |
| 21 | |
| 22 | #include <osmocom/gsupclient/gsup_client.h> |
| 23 | |
| 24 | #include <osmocom/msc/debug.h> |
| 25 | #include <osmocom/msc/gsup_client_mux.h> |
| 26 | |
| 27 | static enum osmo_gsup_message_class gsup_client_mux_classify(struct gsup_client_mux *gcm, |
| 28 | const struct osmo_gsup_message *gsup_msg) |
| 29 | { |
| 30 | if (gsup_msg->message_class) |
| 31 | return gsup_msg->message_class; |
| 32 | |
| 33 | LOGP(DLGSUP, LOGL_DEBUG, "No explicit GSUP Message Class, trying to guess from message type %s\n", |
| 34 | osmo_gsup_message_type_name(gsup_msg->message_type)); |
| 35 | |
| 36 | switch (gsup_msg->message_type) { |
| 37 | case OSMO_GSUP_MSGT_PROC_SS_REQUEST: |
| 38 | case OSMO_GSUP_MSGT_PROC_SS_RESULT: |
| 39 | case OSMO_GSUP_MSGT_PROC_SS_ERROR: |
| 40 | return OSMO_GSUP_MESSAGE_CLASS_USSD; |
| 41 | |
| 42 | /* GSM 04.11 code implementing MO SMS */ |
| 43 | case OSMO_GSUP_MSGT_MO_FORWARD_SM_ERROR: |
| 44 | case OSMO_GSUP_MSGT_MO_FORWARD_SM_RESULT: |
| 45 | case OSMO_GSUP_MSGT_READY_FOR_SM_ERROR: |
| 46 | case OSMO_GSUP_MSGT_READY_FOR_SM_RESULT: |
| 47 | case OSMO_GSUP_MSGT_MT_FORWARD_SM_REQUEST: |
| 48 | return OSMO_GSUP_MESSAGE_CLASS_SMS; |
| 49 | |
| 50 | default: |
| 51 | return OSMO_GSUP_MESSAGE_CLASS_SUBSCRIBER_MANAGEMENT; |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | /* Non-static for unit tests */ |
| 56 | int gsup_client_mux_rx(struct osmo_gsup_client *gsup_client, struct msgb *msg) |
| 57 | { |
| 58 | struct gsup_client_mux *gcm = gsup_client->data; |
| 59 | struct osmo_gsup_message gsup; |
| 60 | enum osmo_gsup_message_class message_class; |
| 61 | int rc; |
| 62 | |
| 63 | rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup); |
| 64 | if (rc < 0) { |
| 65 | LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: '%s' (%d) [ %s]\n", |
| 66 | get_value_string(gsm48_gmm_cause_names, -rc), -rc, osmo_hexdump(msg->data, msg->len)); |
| 67 | goto msgb_free_and_return; |
| 68 | } |
| 69 | |
| 70 | if (!gsup.imsi[0]) { |
| 71 | LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: missing IMSI\n"); |
| 72 | if (OSMO_GSUP_IS_MSGT_REQUEST(gsup.message_type)) |
| 73 | gsup_client_mux_tx_error_reply(gcm, &gsup, GMM_CAUSE_INV_MAND_INFO); |
| 74 | rc = -GMM_CAUSE_INV_MAND_INFO; |
| 75 | goto msgb_free_and_return; |
| 76 | } |
| 77 | |
| 78 | message_class = gsup_client_mux_classify(gcm, &gsup); |
| 79 | |
| 80 | if (message_class <= OSMO_GSUP_MESSAGE_CLASS_UNSET || message_class >= ARRAY_SIZE(gcm->rx_cb)) { |
| 81 | LOGP(DLGSUP, LOGL_ERROR, "Failed to classify GSUP message target\n"); |
| 82 | rc = -EINVAL; |
| 83 | goto msgb_free_and_return; |
| 84 | } |
| 85 | |
| 86 | if (!gcm->rx_cb[message_class].func) { |
| 87 | LOGP(DLGSUP, LOGL_ERROR, "No receiver set up for GSUP Message Class %s\n", osmo_gsup_message_class_name(message_class)); |
| 88 | rc = -ENOTSUP; |
| 89 | goto msgb_free_and_return; |
| 90 | } |
| 91 | |
| 92 | rc = gcm->rx_cb[message_class].func(gcm, gcm->rx_cb[message_class].data, &gsup); |
| 93 | |
| 94 | msgb_free_and_return: |
| 95 | msgb_free(msg); |
| 96 | return rc; |
| 97 | } |
| 98 | |
| 99 | /* Make it clear that struct gsup_client_mux should be talloc allocated, so that it can be used as talloc parent. */ |
| 100 | struct gsup_client_mux *gsup_client_mux_alloc(void *talloc_ctx) |
| 101 | { |
| 102 | return talloc_zero(talloc_ctx, struct gsup_client_mux); |
| 103 | } |
| 104 | |
| 105 | /* Start a GSUP client to serve this gsup_client_mux. */ |
| 106 | int gsup_client_mux_start(struct gsup_client_mux *gcm, const char *gsup_server_addr_str, uint16_t gsup_server_port, |
| 107 | struct ipaccess_unit *ipa_dev) |
| 108 | { |
| 109 | gcm->gsup_client = osmo_gsup_client_create2(gcm, ipa_dev, |
| 110 | gsup_server_addr_str, |
| 111 | gsup_server_port, |
| 112 | &gsup_client_mux_rx, NULL); |
| 113 | if (!gcm->gsup_client) |
| 114 | return -ENOMEM; |
| 115 | gcm->gsup_client->data = gcm; |
| 116 | return 0; |
| 117 | } |
| 118 | |
| 119 | int gsup_client_mux_tx(struct gsup_client_mux *gcm, const struct osmo_gsup_message *gsup_msg) |
| 120 | { |
| 121 | struct msgb *msg; |
| 122 | int rc; |
| 123 | |
| 124 | if (!gcm || !gcm->gsup_client) { |
| 125 | LOGP(DLGSUP, LOGL_ERROR, "GSUP link is down, cannot send GSUP message\n"); |
| 126 | return -ENOTSUP; |
| 127 | } |
| 128 | |
| 129 | msg = osmo_gsup_client_msgb_alloc(); |
| 130 | rc = osmo_gsup_encode(msg, gsup_msg); |
| 131 | if (rc < 0) { |
| 132 | LOGP(DLGSUP, LOGL_ERROR, "Failed to encode GSUP message: '%s'\n", strerror(-rc)); |
| 133 | return rc; |
| 134 | } |
| 135 | |
| 136 | return osmo_gsup_client_send(gcm->gsup_client, msg); |
| 137 | } |
| 138 | |
| 139 | /* Transmit GSUP error in response to original message */ |
| 140 | void gsup_client_mux_tx_error_reply(struct gsup_client_mux *gcm, const struct osmo_gsup_message *gsup_orig, |
| 141 | enum gsm48_gmm_cause cause) |
| 142 | { |
| 143 | struct osmo_gsup_message gsup_reply; |
| 144 | |
| 145 | /* No need to answer if we couldn't parse an ERROR message type, only REQUESTs need an error reply. */ |
| 146 | if (!OSMO_GSUP_IS_MSGT_REQUEST(gsup_orig->message_type)) |
| 147 | return; |
| 148 | |
Neels Hofmeyr | c4628a3 | 2018-12-07 14:47:34 +0100 | [diff] [blame] | 149 | gsup_reply = (struct osmo_gsup_message){ |
| 150 | .cause = cause, |
| 151 | .message_type = OSMO_GSUP_TO_MSGT_ERROR(gsup_orig->message_type), |
Vadim Yanitskiy | c33d94b | 2019-06-15 01:31:50 +0700 | [diff] [blame] | 152 | .message_class = gsup_orig->message_class, |
Vadim Yanitskiy | 20edc97 | 2019-06-15 03:10:33 +0700 | [diff] [blame] | 153 | |
| 154 | /* RP-Message-Reference is mandatory for SM Service */ |
| 155 | .sm_rp_mr = gsup_orig->sm_rp_mr, |
Neels Hofmeyr | c4628a3 | 2018-12-07 14:47:34 +0100 | [diff] [blame] | 156 | }; |
| 157 | |
Vadim Yanitskiy | 4d0066c | 2019-06-15 01:08:16 +0700 | [diff] [blame] | 158 | OSMO_STRLCPY_ARRAY(gsup_reply.imsi, gsup_orig->imsi); |
| 159 | |
Vadim Yanitskiy | 463005e | 2019-06-15 01:28:35 +0700 | [diff] [blame] | 160 | /* For SS/USSD, it's important to keep both session state and ID IEs */ |
| 161 | if (gsup_orig->session_state != OSMO_GSUP_SESSION_STATE_NONE) { |
| 162 | gsup_reply.session_state = OSMO_GSUP_SESSION_STATE_END; |
| 163 | gsup_reply.session_id = gsup_orig->session_id; |
| 164 | } |
| 165 | |
Neels Hofmeyr | c4628a3 | 2018-12-07 14:47:34 +0100 | [diff] [blame] | 166 | if (osmo_gsup_client_enc_send(gcm->gsup_client, &gsup_reply)) |
| 167 | LOGP(DLGSUP, LOGL_ERROR, "Failed to send Error reply (imsi=%s)\n", |
| 168 | osmo_quote_str(gsup_orig->imsi, -1)); |
| 169 | } |