add pfcp_endpoint

Related: SYS#5599
Change-Id: Ic8d42e201b63064a71b40ca45a5a40e29941e8ac

3 files changed, 111 insertions, 0 deletions

diff --git a/include/osmocom/pfcp/Makefile.am b/include/osmocom/pfcp/Makefile.am
index 7bd5ea3..5d2db19 100644
--- a/include/osmocom/pfcp/Makefile.am
+++ b/include/osmocom/pfcp/Makefile.am
@@ -1,4 +1,5 @@
 pfcp_HEADERS = \
+	pfcp_endpoint.h \
 	pfcp_ies_custom.h \
 	pfcp_ies_auto.h \
 	pfcp_msg.h \
diff --git a/include/osmocom/pfcp/pfcp_endpoint.h b/include/osmocom/pfcp/pfcp_endpoint.h
new file mode 100644
index 0000000..acc878e
--- /dev/null
+++ b/include/osmocom/pfcp/pfcp_endpoint.h
@@ -0,0 +1,107 @@
+/*
+ * (C) 2021-2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved.
+ *
+ * Author: Neels Janosch Hofmeyr <nhofmeyr@sysmocom.de>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ *  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/core/socket.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/tdef.h>
+
+#include <osmocom/pfcp/pfcp_msg.h>
+
+struct osmo_pfcp_endpoint;
+struct osmo_fsm_inst;
+
+#define OSMO_PFCP_TIMER_HEARTBEAT_REQ -19
+#define OSMO_PFCP_TIMER_HEARTBEAT_RESP -20
+#define OSMO_PFCP_TIMER_GRACEFUL_REL -21
+#define OSMO_PFCP_TIMER_T1 -22
+#define OSMO_PFCP_TIMER_N1 -23
+#define OSMO_PFCP_TIMER_KEEP_RESP -24
+#define OSMO_PFCP_TIMER_ASSOC_RETRY -26
+
+extern struct osmo_tdef osmo_pfcp_tdefs[];
+
+/* Ownership of m remains with the caller / m will be deallocated by the caller.
+ * \param ep  The PFCP endpoint that received and decoded the message.
+ * \param m  The message that was received.
+ * \param req  If m is a PFCP Response to an earlier Request, req is that request message. Otherwise req is NULL.
+ */
+typedef void (*osmo_pfcp_endpoint_cb)(struct osmo_pfcp_endpoint *ep, struct osmo_pfcp_msg *m,
+				      struct osmo_pfcp_msg *req);
+
+/* Send/receive PFCP messages to/from remote PFCP endpoints. */
+struct osmo_pfcp_endpoint {
+	struct {
+		/* Local address */
+		struct osmo_sockaddr local_addr;
+		/* Local PFCP Node ID, as sent in outgoing messages' Node ID IE */
+		struct osmo_pfcp_ie_node_id local_node_id;
+
+		/* Timer definitions to use, if any. See t1_ms, keep_resp_ms. Use osmo_pfcp_tdefs by default. It is
+		 * convenient to add osmo_pfcp_tdefs as one of your program's osmo_tdef_group entries and call
+		 * osmo_tdef_vty_init() to expose PFCP timers on the VTY. */
+		const struct osmo_tdef *tdefs;
+	} cfg;
+
+	/* PFCP socket */
+	struct osmo_fd pfcp_fd;
+
+	/* The time at which this endpoint last restarted, as seconds since unix epoch. */
+	uint32_t recovery_time_stamp;
+
+	/* State for determining the next sequence number for transmitting a request message */
+	uint32_t seq_nr_state;
+
+	/* This function is called just after decoding and before handling the message.
+	 * This function may set ctx.peer_fi and ctx.session_fi, used for logging context during message decoding.
+	 * The caller may also use these fi pointers to reduce lookup iterations in rx_msg().
+	 */
+	osmo_pfcp_endpoint_cb set_msg_ctx;
+
+	/* Callback to receive single incoming PFCP messages from a remote peer, already decoded. */
+	osmo_pfcp_endpoint_cb rx_msg;
+
+	/* application-private data */
+	void *priv;
+
+	/* All transmitted PFCP Request messages, list of osmo_pfcp_queue_entry.
+	 * For a transmitted Request message, wait for a matching Response from a remote peer; if none arrives,
+	 * retransmit (see n1 and t1_ms). */
+	struct llist_head sent_requests;
+	/* All transmitted PFCP Response messages, list of osmo_pfcp_queue_entry.
+	 * For a transmitted Response message, keep it in the queue for a fixed amount of time. If the peer retransmits
+	 * the original Request, do not dispatch the Request, but respond with the queued message directly. */
+	struct llist_head sent_responses;
+};
+
+struct osmo_pfcp_endpoint *osmo_pfcp_endpoint_create(void *ctx, void *priv);
+int osmo_pfcp_endpoint_bind(struct osmo_pfcp_endpoint *ep);
+void osmo_pfcp_endpoint_close(struct osmo_pfcp_endpoint *ep);
+void osmo_pfcp_endpoint_free(struct osmo_pfcp_endpoint **ep);
+
+int osmo_pfcp_endpoint_tx(struct osmo_pfcp_endpoint *ep, struct osmo_pfcp_msg *m);
+int osmo_pfcp_endpoint_tx_data(struct osmo_pfcp_endpoint *ep, struct osmo_pfcp_msg *m);
+int osmo_pfcp_endpoint_tx_heartbeat_req(struct osmo_pfcp_endpoint *ep, const struct osmo_sockaddr *remote_addr);
+
+void osmo_pfcp_endpoint_invalidate_ctx(struct osmo_pfcp_endpoint *ep, struct osmo_fsm_inst *deleted_fi);
diff --git a/include/osmocom/pfcp/pfcp_msg.h b/include/osmocom/pfcp/pfcp_msg.h
index 949800e..2833408 100644
--- a/include/osmocom/pfcp/pfcp_msg.h
+++ b/include/osmocom/pfcp/pfcp_msg.h
@@ -147,6 +147,9 @@ struct osmo_pfcp_msg {
 		osmo_pfcp_resp_cb resp_cb;
 		void *priv;
 	} ctx;
+
+	/* When a message gets encoded, the encoded packet is cached here for possible retransmissions. */
+	struct msgb *encoded;
 };
 
 /* Given a &osmo_pfcp_msg->ies pointer, return the &osmo_pfcp_msg.