lynxis lazus has submitted this change. ( 
https://gerrit.osmocom.org/c/osmo-hlr/+/38112?usp=email )

Change subject: gsupclient: Introduce gsup_client_mux
......................................................................

gsupclient: Introduce gsup_client_mux

GSUP supports different message classes (e.g. SMS, USSD, Subscriber management),
within a daemon, the messages are usually handled in different parts of it.
The gsup client mux allow to place callbacks for the different message class.

This code original comes from the osmo-msc code and is here
re-licensed under the GPLv2.

Change-Id: I916c1bb6cfc48f92fc5db2b5c914eb1b4e25fa7f
---
M include/Makefile.am
A include/osmocom/gsupclient/gsup_client_mux.h
M src/gsupclient/Makefile.am
A src/gsupclient/gsup_client_mux.c
4 files changed, 252 insertions(+), 0 deletions(-)

Approvals:
  laforge: Looks good to me, but someone else must approve
  pespin: Looks good to me, but someone else must approve
  fixeria: Looks good to me, but someone else must approve
  lynxis lazus: Looks good to me, approved
  Jenkins Builder: Verified




diff --git a/include/Makefile.am b/include/Makefile.am
index e93fe29..f3baca6 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -3,6 +3,7 @@
 nobase_include_HEADERS = \
        osmocom/gsupclient/cni_peer_id.h \
        osmocom/gsupclient/gsup_client.h \
+       osmocom/gsupclient/gsup_client_mux.h \
        osmocom/gsupclient/gsup_req.h \
        osmocom/mslookup/mdns.h \
        osmocom/mslookup/mdns_sock.h \
diff --git a/include/osmocom/gsupclient/gsup_client_mux.h 
b/include/osmocom/gsupclient/gsup_client_mux.h
new file mode 100644
index 0000000..537ae60
--- /dev/null
+++ b/include/osmocom/gsupclient/gsup_client_mux.h
@@ -0,0 +1,56 @@
+/*
+ * (C) 2019 by sysmocom - s.f.m.c. GmbH <[email protected]>
+ * All Rights Reserved
+ *
+ * Author: Neels Hofmeyr
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <osmocom/gsm/gsup.h>
+
+struct gsup_client_mux;
+struct ipaccess_unit;
+
+struct gsup_client_mux_rx_cb {
+       int (*func)(struct gsup_client_mux *gcm, void *data, const struct 
osmo_gsup_message *gsup_msg);
+       void *data;
+};
+
+/* A GSUP client shared between code paths for various GSUP Message Classes.
+ * The main task is to dispatch GSUP messages to code paths corresponding to 
the respective Message Class, i.e.
+ * subscriber management, SMS, SS/USSD and inter-MSC messaging.
+ * If a GSUP Message Class IE is present in the message, the received message 
is dispatched directly to the rx_cb entry
+ * for that Message Class. Otherwise, the Message Class is determined by a 
switch() on the Message Type.*/
+struct gsup_client_mux {
+       struct osmo_gsup_client *gsup_client;
+
+       /* Target clients by enum osmo_gsup_message_class */
+       struct gsup_client_mux_rx_cb rx_cb[OSMO_GSUP_MESSAGE_CLASS_ARRAYSIZE];
+};
+
+struct gsup_client_mux *gsup_client_mux_alloc(void *talloc_ctx);
+int gsup_client_mux_start(struct gsup_client_mux *gcm, const char 
*gsup_server_addr_str, uint16_t gsup_server_port,
+                         struct ipaccess_unit *ipa_dev);
+
+int gsup_client_mux_tx(struct gsup_client_mux *gcm, const struct 
osmo_gsup_message *gsup_msg);
+void gsup_client_mux_tx_set_source(const struct gsup_client_mux *gcm, struct 
osmo_gsup_message *gsup_msg);
+void gsup_client_mux_tx_error_reply(struct gsup_client_mux *gcm, const struct 
osmo_gsup_message *gsup_orig,
+                                   enum gsm48_gmm_cause cause);
+
+int gsup_client_mux_rx(struct osmo_gsup_client *gsup_client, struct msgb *msg);
diff --git a/src/gsupclient/Makefile.am b/src/gsupclient/Makefile.am
index a627ccc..ab9c478 100644
--- a/src/gsupclient/Makefile.am
+++ b/src/gsupclient/Makefile.am
@@ -11,6 +11,7 @@
 libosmo_gsup_client_la_SOURCES = \
        cni_peer_id.c \
        gsup_client.c \
+       gsup_client_mux.c \
        gsup_req.c \
        $(NULL)

diff --git a/src/gsupclient/gsup_client_mux.c b/src/gsupclient/gsup_client_mux.c
new file mode 100644
index 0000000..7699ca1
--- /dev/null
+++ b/src/gsupclient/gsup_client_mux.c
@@ -0,0 +1,194 @@
+/* Directing individual GSUP messages to their respective handlers. */
+/*
+ * (C) 2019 by sysmocom - s.f.m.c. GmbH <[email protected]>
+ * All Rights Reserved
+ *
+ * Author: Neels Hofmeyr
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <errno.h>
+
+#include <osmocom/core/logging.h>
+
+#include <osmocom/gsupclient/gsup_client.h>
+#include <osmocom/gsupclient/gsup_client_mux.h>
+
+static enum osmo_gsup_message_class gsup_client_mux_classify(struct 
gsup_client_mux *gcm,
+                                                   const struct 
osmo_gsup_message *gsup_msg)
+{
+       if (gsup_msg->message_class)
+               return gsup_msg->message_class;
+
+       LOGP(DLGSUP, LOGL_DEBUG, "No explicit GSUP Message Class, trying to 
guess from message type %s\n",
+            osmo_gsup_message_type_name(gsup_msg->message_type));
+
+       switch (gsup_msg->message_type) {
+       case OSMO_GSUP_MSGT_PROC_SS_REQUEST:
+       case OSMO_GSUP_MSGT_PROC_SS_RESULT:
+       case OSMO_GSUP_MSGT_PROC_SS_ERROR:
+               return OSMO_GSUP_MESSAGE_CLASS_USSD;
+
+       /* GSM 04.11 code implementing MO SMS */
+       case OSMO_GSUP_MSGT_MO_FORWARD_SM_ERROR:
+       case OSMO_GSUP_MSGT_MO_FORWARD_SM_RESULT:
+       case OSMO_GSUP_MSGT_READY_FOR_SM_ERROR:
+       case OSMO_GSUP_MSGT_READY_FOR_SM_RESULT:
+       case OSMO_GSUP_MSGT_MT_FORWARD_SM_REQUEST:
+               return OSMO_GSUP_MESSAGE_CLASS_SMS;
+
+       default:
+               return OSMO_GSUP_MESSAGE_CLASS_SUBSCRIBER_MANAGEMENT;
+       }
+}
+
+/* Non-static for unit tests */
+int gsup_client_mux_rx(struct osmo_gsup_client *gsup_client, struct msgb *msg)
+{
+       struct gsup_client_mux *gcm = gsup_client->data;
+       struct osmo_gsup_message gsup;
+       enum osmo_gsup_message_class message_class;
+       int rc;
+
+       rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup);
+       if (rc < 0) {
+               LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: '%s' 
(%d) [ %s]\n",
+                    get_value_string(gsm48_gmm_cause_names, -rc), -rc, 
osmo_hexdump(msg->data, msg->len));
+               goto msgb_free_and_return;
+       }
+
+       if (!gsup.imsi[0]) {
+               LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: 
missing IMSI\n");
+               if (OSMO_GSUP_IS_MSGT_REQUEST(gsup.message_type))
+                       gsup_client_mux_tx_error_reply(gcm, &gsup, 
GMM_CAUSE_INV_MAND_INFO);
+               rc = -GMM_CAUSE_INV_MAND_INFO;
+               goto msgb_free_and_return;
+       }
+
+       message_class = gsup_client_mux_classify(gcm, &gsup);
+
+       if (message_class <= OSMO_GSUP_MESSAGE_CLASS_UNSET || message_class >= 
ARRAY_SIZE(gcm->rx_cb)) {
+               LOGP(DLGSUP, LOGL_ERROR, "Failed to classify GSUP message 
target\n");
+               rc = -EINVAL;
+               goto msgb_free_and_return;
+       }
+
+       if (!gcm->rx_cb[message_class].func) {
+               LOGP(DLGSUP, LOGL_ERROR, "No receiver set up for GSUP Message 
Class %s\n", osmo_gsup_message_class_name(message_class));
+               rc = -ENOTSUP;
+               goto msgb_free_and_return;
+       }
+
+       rc = gcm->rx_cb[message_class].func(gcm, 
gcm->rx_cb[message_class].data, &gsup);
+
+msgb_free_and_return:
+       msgb_free(msg);
+       return rc;
+}
+
+/* Make it clear that struct gsup_client_mux should be talloc allocated, so 
that it can be used as talloc parent. */
+struct gsup_client_mux *gsup_client_mux_alloc(void *talloc_ctx)
+{
+       return talloc_zero(talloc_ctx, struct gsup_client_mux);
+}
+
+/* Start a GSUP client to serve this gsup_client_mux. */
+int gsup_client_mux_start(struct gsup_client_mux *gcm, const char 
*gsup_server_addr_str, uint16_t gsup_server_port,
+                         struct ipaccess_unit *ipa_dev)
+{
+       gcm->gsup_client = osmo_gsup_client_create2(gcm, ipa_dev,
+                                                   gsup_server_addr_str,
+                                                   gsup_server_port,
+                                                   &gsup_client_mux_rx, NULL);
+       if (!gcm->gsup_client)
+               return -ENOMEM;
+       gcm->gsup_client->data = gcm;
+       return 0;
+}
+
+int gsup_client_mux_tx(struct gsup_client_mux *gcm, const struct 
osmo_gsup_message *gsup_msg)
+{
+       struct msgb *msg;
+       int rc;
+
+       if (!gcm || !gcm->gsup_client) {
+               LOGP(DLGSUP, LOGL_ERROR, "GSUP link is down, cannot send GSUP 
message\n");
+               return -ENOTSUP;
+       }
+
+       msg = osmo_gsup_client_msgb_alloc();
+       rc = osmo_gsup_encode(msg, gsup_msg);
+       if (rc < 0) {
+               LOGP(DLGSUP, LOGL_ERROR, "Failed to encode GSUP message: 
'%s'\n", strerror(-rc));
+               return rc;
+       }
+
+       return osmo_gsup_client_send(gcm->gsup_client, msg);
+}
+
+/* Set GSUP source_name to our local IPA name */
+void gsup_client_mux_tx_set_source(const struct gsup_client_mux *gcm,
+                                  struct osmo_gsup_message *gsup_msg)
+{
+       const char *local_msc_name;
+
+       if (!gcm)
+               return;
+       if (!gcm->gsup_client)
+               return;
+       if (!gcm->gsup_client->ipa_dev)
+               return;
+       local_msc_name = gcm->gsup_client->ipa_dev->serno;
+       if (!local_msc_name)
+               return;
+       gsup_msg->source_name = (const uint8_t *) local_msc_name;
+       gsup_msg->source_name_len = strlen(local_msc_name) + 1;
+}
+
+/* Transmit GSUP error in response to original message */
+void gsup_client_mux_tx_error_reply(struct gsup_client_mux *gcm, const struct 
osmo_gsup_message *gsup_orig,
+                                   enum gsm48_gmm_cause cause)
+{
+       struct osmo_gsup_message gsup_reply;
+
+       /* No need to answer if we couldn't parse an ERROR message type, only 
REQUESTs need an error reply. */
+       if (!OSMO_GSUP_IS_MSGT_REQUEST(gsup_orig->message_type))
+               return;
+
+       gsup_reply = (struct osmo_gsup_message){
+               .cause = cause,
+               .message_type = 
OSMO_GSUP_TO_MSGT_ERROR(gsup_orig->message_type),
+               .message_class = gsup_orig->message_class,
+               .destination_name = gsup_orig->source_name,
+               .destination_name_len = gsup_orig->source_name_len,
+
+               /* RP-Message-Reference is mandatory for SM Service */
+               .sm_rp_mr = gsup_orig->sm_rp_mr,
+       };
+
+       OSMO_STRLCPY_ARRAY(gsup_reply.imsi, gsup_orig->imsi);
+       gsup_client_mux_tx_set_source(gcm, &gsup_reply);
+
+       /* For SS/USSD, it's important to keep both session state and ID IEs */
+       if (gsup_orig->session_state != OSMO_GSUP_SESSION_STATE_NONE) {
+               gsup_reply.session_state = OSMO_GSUP_SESSION_STATE_END;
+               gsup_reply.session_id = gsup_orig->session_id;
+       }
+
+       if (osmo_gsup_client_enc_send(gcm->gsup_client, &gsup_reply))
+               LOGP(DLGSUP, LOGL_ERROR, "Failed to send Error reply 
(imsi=%s)\n",
+                    osmo_quote_str(gsup_orig->imsi, -1));
+}

--
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Gerrit-MessageType: merged
Gerrit-Project: osmo-hlr
Gerrit-Branch: master
Gerrit-Change-Id: I916c1bb6cfc48f92fc5db2b5c914eb1b4e25fa7f
Gerrit-Change-Number: 38112
Gerrit-PatchSet: 5
Gerrit-Owner: lynxis lazus <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: lynxis lazus <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>

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