1 files changed, 119 insertions, 0 deletions
diff --git a/include/osmocom/gsupclient/gsup_req.h b/include/osmocom/gsupclient/gsup_req.h
new file mode 100644
index 0000000..c61483b
--- /dev/null
+++ b/include/osmocom/gsupclient/gsup_req.h
@@ -0,0 +1,119 @@
+/* Copyright 2019 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * 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>
+#include <osmocom/gsupclient/ipa_name.h>
+
+struct osmo_gsup_req;
+
+#define LOG_GSUP_REQ_CAT_SRC(req, subsys, level, file, line, fmt, args...) \
+	LOGPSRC(subsys, level, file, line, "GSUP %u: %s: IMSI-%s %s: " fmt, \
+		(req) ? (req)->nr : 0, \
+		(req) ? osmo_ipa_name_to_str(&(req)->source_name) : "NULL", \
+		(req) ? (req)->gsup.imsi : "NULL", \
+		(req) ? osmo_gsup_message_type_name((req)->gsup.message_type) : "NULL", \
+		##args)
+#define LOG_GSUP_REQ_CAT(req, subsys, level, fmt, args...) \
+	LOG_GSUP_REQ_CAT_SRC(req, subsys, level, __FILE__, __LINE__, fmt, ##args)
+
+#define LOG_GSUP_REQ_SRC(req, level, file, line, fmt, args...) \
+	LOG_GSUP_REQ_CAT_SRC(req, DLGSUP, level, file, line, fmt, ##args)
+
+#define LOG_GSUP_REQ(req, level, fmt, args...) \
+	LOG_GSUP_REQ_SRC(req, level, __FILE__, __LINE__, fmt, ##args)
+
+typedef void (*osmo_gsup_req_send_response_t)(struct osmo_gsup_req *req, struct osmo_gsup_message *response);
+
+/* Keep track of an incoming request, to route back a response when it is ready.
+ * Particularly, a GSUP response to a request must contain various bits of information that need to be copied from the
+ * request for proxy/routing to work and for session states to remain valid. That is the main reason why (almost) all
+ * GSUP request/response should go through an osmo_gsup_req, even if it is handled synchronously.
+ */
+struct osmo_gsup_req {
+	/* The incoming GSUP message in decoded form. */
+	const struct osmo_gsup_message gsup;
+
+	/* Decoding result code. If decoding failed, this will be != 0. */
+	int decode_rc;
+
+	/* The ultimate source of this message: the source_name form the GSUP message, or, if not present, then the
+	 * immediate GSUP peer. GSUP messages going via a proxy reflect the initial source in the source_name.
+	 * This source_name is implicitly added to the routes for the conn the message was received on. */
+	struct osmo_ipa_name source_name;
+
+	/* If the source_name is not an immediate GSUP peer, this is set to the closest intermediate peer between here
+	 * and source_name. */
+	struct osmo_ipa_name via_proxy;
+
+	/* Identify this request by number, for logging. */
+	unsigned int nr;
+
+	/* osmo_gsup_req can be used by both gsup_server and gsup_client. The individual method of actually sending a
+	 * GSUP message is provided by this callback. */
+	osmo_gsup_req_send_response_t send_response_cb;
+
+	/* User supplied data pointer, may be used to provide context to send_response_cb(). */
+	void *cb_data;
+
+	/* List entry that can be used to keep a list of osmo_gsup_req instances; not used directly by osmo_gsup_req.c,
+	 * it is up to using implementations to keep a list. If this is non-NULL, osmo_gsup_req_free() calls
+	 * llist_del() on this. */
+	struct llist_head entry;
+
+	/* A decoded GSUP message still points into the received msgb. For a decoded osmo_gsup_message to remain valid,
+	 * we also need to keep the msgb. */
+	struct msgb *msg;
+};
+
+struct osmo_gsup_req *osmo_gsup_req_new(void *ctx, const struct osmo_ipa_name *from_peer, struct msgb *msg,
+					osmo_gsup_req_send_response_t send_response_cb, void *cb_data,
+					struct llist_head *add_to_list);
+void osmo_gsup_req_free(struct osmo_gsup_req *req);
+
+/*! See _osmo_gsup_req_respond() for details.
+ * Call _osmo_gsup_req_respond(), passing the caller's source file and line for logging. */
+#define osmo_gsup_req_respond(REQ, RESPONSE, ERROR, FINAL_RESPONSE) \
+	_osmo_gsup_req_respond(REQ, RESPONSE, ERROR, FINAL_RESPONSE, __FILE__, __LINE__)
+int _osmo_gsup_req_respond(struct osmo_gsup_req *req, struct osmo_gsup_message *response,
+			   bool error, bool final_response, const char *file, int line);
+
+/*! See _osmo_gsup_req_respond_msgt() for details.
+ * Call _osmo_gsup_req_respond_msgt(), passing the caller's source file and line for logging. */
+#define osmo_gsup_req_respond_msgt(REQ, MESSAGE_TYPE, FINAL_RESPONSE) \
+	_osmo_gsup_req_respond_msgt(REQ, MESSAGE_TYPE, FINAL_RESPONSE, __FILE__, __LINE__)
+int _osmo_gsup_req_respond_msgt(struct osmo_gsup_req *req, enum osmo_gsup_message_type message_type,
+				bool final_response, const char *file, int line);
+
+/*! See _osmo_gsup_req_respond_err() for details.
+ * Log an error message, and call _osmo_gsup_req_respond_err(), passing the caller's source file and line for logging.
+ */
+#define osmo_gsup_req_respond_err(REQ, CAUSE, FMT, args...) do { \
+		LOG_GSUP_REQ(REQ, LOGL_ERROR, "%s: " FMT "\n", \
+			     get_value_string(gsm48_gmm_cause_names, CAUSE), ##args); \
+		_osmo_gsup_req_respond_err(REQ, CAUSE, __FILE__, __LINE__); \
+	} while(0)
+void _osmo_gsup_req_respond_err(struct osmo_gsup_req *req, enum gsm48_gmm_cause cause,
+				const char *file, int line);
+
+int osmo_gsup_make_response(struct osmo_gsup_message *reply,
+			    const struct osmo_gsup_message *rx, bool error, bool final_response);
+
+size_t osmo_gsup_message_to_str_buf(char *buf, size_t bufsize, const struct osmo_gsup_message *msg);
+char *osmo_gsup_message_to_str_c(void *ctx, const struct osmo_gsup_message *msg);