add osmo-upf

Related: SYS#5599
Change-Id: I745bcbde6859004c41ddbfd2558036bf9a2d1de2

doc/examples/osmo-upf/osmo-upf-create-dev.cfg

@@ -0,0 +1,16 @@
+log stderr
+ logging filter all 1
+ logging color 1
+ logging print level 1
+ logging print category 1
+ logging print category-hex 0
+ logging print file basename last
+ logging print extended-timestamp 1
+ logging level set-all info
+#logging level set-all debug
+
+timer pfcp x24 5000
+pfcp
+ local-addr 127.0.0.1
+gtp
+ dev create apn23

doc/examples/osmo-upf/osmo-upf.cfg

@@ -6,4 +6,10 @@ log stderr
  logging print category-hex 0
  logging print file basename last
  logging print extended-timestamp 1
+ logging level set-all debug
  logging level set-all notice
+ logging level set-all info
+
+timer pfcp x24 5000
+pfcp
+ local-addr 127.0.0.1

include/osmocom/upf/Makefile.am

@@ -1,3 +1,9 @@
 noinst_HEADERS = \
+	up_endpoint.h \
+	up_peer.h \
+	up_session.h \
 	upf.h \
+	upf_gtp.h \
+	upf_nft.h \
+	up_gtp_action.h \
 	$(NULL)

include/osmocom/upf/up_endpoint.h

@@ -0,0 +1,48 @@
+/*
+ * (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/linuxlist.h>
+
+struct osmo_pfcp_msg;
+struct osmo_pfcp_endpoint;
+struct osmo_sockaddr;
+
+#define UP_USE_MSG_RX "msg-rx"
+#define UP_USE_MSG_TX "msg-tx"
+
+struct up_endpoint {
+	struct osmo_pfcp_endpoint *pfcp_ep;
+
+	struct llist_head peers;
+
+	uint64_t next_seid_state;
+	uint32_t next_teid_state;
+};
+
+struct up_endpoint *up_endpoint_init(void *ctx, const struct osmo_sockaddr *local_addr);
+void up_endpoint_free(struct up_endpoint **ep);
+
+uint64_t up_endpoint_next_seid(struct up_endpoint *ep);
+uint32_t up_endpoint_next_teid(struct up_endpoint *ep);

include/osmocom/upf/up_gtp_action.h

@@ -0,0 +1,73 @@
+/*
+ * (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 <stdint.h>
+
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/fsm.h>
+
+#include <osmocom/upf/up_session.h>
+#include <osmocom/upf/upf_gtp.h>
+#include <osmocom/upf/upf_nft.h>
+
+#define LOG_UP_GTP_ACTION(A, LEVEL, FMT, ARGS...) \
+	LOGP(DGTP, LEVEL, "%s: " FMT, up_gtp_action_to_str_c(OTC_SELECT, A), ##ARGS)
+
+struct up_session;
+
+enum up_gtp_action_kind {
+	UP_GTP_DROP,
+	UP_GTP_U_ENDECAPS,
+	UP_GTP_U_TUNMAP,
+};
+
+struct up_gtp_action {
+	struct llist_head entry;
+	struct up_session *session;
+
+	uint16_t pdr_core;
+	uint16_t pdr_access;
+
+	enum up_gtp_action_kind kind;
+	union {
+		/* En-/De-capsulate GTP: add/remove a GTP header and forward the GTP payload from/to plain IP. */
+		struct upf_gtp_tun_desc endecaps;
+
+		/* Tunnel-map GTP: translate from one TEID to another and forward */
+		struct upf_nft_tunmap_desc tunmap;
+	};
+
+	/* volatile loop variable to match up wanted and actually present GTP actions */
+	void *handle;
+};
+
+int up_gtp_action_cmp(const struct up_gtp_action *a, const struct up_gtp_action *b);
+
+int up_gtp_action_enable(struct up_gtp_action *a);
+int up_gtp_action_disable(struct up_gtp_action *a);
+
+int up_gtp_action_to_str_buf(char *buf, size_t buflen, const struct up_gtp_action *a);
+char *up_gtp_action_to_str_c(void *ctx, const struct up_gtp_action *a);

include/osmocom/upf/up_peer.h

@@ -0,0 +1,78 @@
+/*
+ * (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/linuxlist.h>
+#include <osmocom/core/hashtable.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/use_count.h>
+
+#include <osmocom/pfcp/pfcp_msg.h>
+
+enum up_peer_event {
+	UP_PEER_EV_RX_ASSOC_SETUP_REQ,
+	UP_PEER_EV_RX_ASSOC_UPD_REQ,
+	UP_PEER_EV_RX_ASSOC_REL_REQ,
+	UP_PEER_EV_RX_SESSION_EST_REQ,
+	UP_PEER_EV_HEARTBEAT_FAILURE,
+	UP_PEER_EV_USE_COUNT_ZERO,
+	UP_PEER_EV_SESSION_TERM,
+};
+
+struct up_peer {
+	struct llist_head entry;
+
+	struct osmo_fsm_inst *fi;
+	struct up_endpoint *up_endpoint;
+
+	/* peer's remote address */
+	struct osmo_sockaddr remote_addr;
+	struct osmo_pfcp_ie_node_id remote_node_id;
+	uint32_t remote_recovery_timestamp;
+
+	struct osmo_pfcp_ie_up_function_features local_up_features;
+	struct osmo_pfcp_ie_cp_function_features peer_cp_features;
+
+	uint32_t next_seq_nr;
+
+	struct osmo_fsm_inst *heartbeat_fi;
+
+	struct osmo_use_count use_count;
+	struct osmo_use_count_entry use_count_buf[5];
+
+	DECLARE_HASHTABLE(sessions_by_up_seid, 6);
+	DECLARE_HASHTABLE(sessions_by_cp_seid, 6);
+};
+
+struct up_peer *up_peer_find_or_add(struct up_endpoint *up_ep, const struct osmo_sockaddr *remote_addr);
+struct up_peer *up_peer_find(struct up_endpoint *up_ep, const struct osmo_sockaddr *remote_addr);
+
+void up_peer_set_msg_ctx(struct up_peer *peer, struct osmo_pfcp_msg *m);
+
+char *up_peer_remote_addr_str(struct up_peer *peer);
+
+struct osmo_pfcp_msg *up_peer_init_tx(struct up_peer *peer, struct osmo_pfcp_msg *in_reply_to,
+				      enum osmo_pfcp_message_type message_type);
+
+void up_peer_free(struct up_peer *peer);

include/osmocom/upf/up_session.h

@@ -0,0 +1,117 @@
+/*
+ * (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 <stdint.h>
+
+#include <osmocom/core/hashtable.h>
+#include <osmocom/core/use_count.h>
+
+#include <osmocom/pfcp/pfcp_msg.h>
+
+struct osmo_fsm_inst;
+struct osmo_pfcp_msg;
+struct up_peer;
+
+enum up_session_fsm_event {
+	UP_SESSION_EV_RX_SESSION_EST_REQ,
+	UP_SESSION_EV_RX_SESSION_MOD_REQ,
+	UP_SESSION_EV_RX_SESSION_DEL_REQ,
+	UP_SESSION_EV_USE_COUNT_ZERO,
+};
+
+enum up_session_kind {
+	UP_SESSION_DROP,
+	UP_SESSION_GTP_U_ENDECAPS,
+	UP_SESSION_GTP_U_FORW,
+};
+
+struct up_session {
+	struct hlist_node node_by_up_seid;
+	struct hlist_node node_by_cp_seid;
+
+	struct osmo_fsm_inst *fi;
+	struct up_peer *up_peer;
+
+	struct osmo_pfcp_ie_f_seid cp_f_seid;
+	uint64_t up_seid;
+
+	struct osmo_use_count use_count;
+	struct osmo_use_count_entry use_count_buf[8];
+
+	struct llist_head pdrs;
+	struct llist_head fars;
+	struct llist_head chosen_f_teids;
+
+	struct llist_head active_gtp_actions;
+};
+
+struct up_session *up_session_find_or_add(struct up_peer *peer, const struct osmo_pfcp_ie_f_seid *cp_f_seid,
+					  const struct osmo_pfcp_ie_f_seid *up_f_seid);
+struct up_session *up_session_find_by_up_seid(struct up_peer *peer, uint64_t up_seid);
+struct up_session *up_session_find_by_cp_f_seid(struct up_peer *peer, const struct osmo_pfcp_ie_f_seid *cp_f_seid);
+struct up_session *up_session_find_by_local_teid(struct up_peer *peer, uint32_t teid);
+
+void up_session_set_msg_ctx(struct up_session *session, struct osmo_pfcp_msg *m);
+
+char *up_session_gtp_status(struct up_session *session);
+bool up_session_is_active(struct up_session *session);
+bool up_session_is_fully_active(struct up_session *session, int *active_p, int *inactive_p);
+
+int up_session_discard(struct up_session *session);
+
+int up_session_to_str_buf(char *buf, size_t buflen, struct up_session *session);
+char *up_session_to_str_c(void *ctx, struct up_session *session);
+
+struct pdr {
+	struct llist_head entry;
+	struct up_session *session;
+
+	struct osmo_pfcp_ie_create_pdr desc;
+	struct osmo_pfcp_ie_f_teid *local_f_teid;
+	struct osmo_pfcp_ie_f_teid _local_f_teid_buf;
+
+	struct far *far;
+
+	bool rx_decaps;
+	bool forw_encaps;
+	bool forw_to_core;
+	bool forw_from_core;
+
+	struct pdr *reverse_pdr;
+	bool active;
+
+	char *inactive_reason;
+};
+
+int pdr_to_str_buf(char *buf, size_t buflen, const struct pdr *pdr);
+char *pdr_to_str_c(void *ctx, const struct pdr *pdr);
+
+struct far {
+	struct llist_head entry;
+	struct up_session *session;
+
+	struct osmo_pfcp_ie_create_far desc;
+	bool active;
+};

include/osmocom/upf/up_session_to_gtp.c

@@ -0,0 +1,23 @@
+/*
+ * (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/>.
+ *
+ */
+

include/osmocom/upf/upf.h

@@ -24,12 +24,78 @@
 
 #pragma once
 
+#include <osmocom/core/tdef.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/linuxlist.h>
+
+struct osmo_tdef;
 struct ctrl_handle;
 
+struct upf_gtp_dev;
+
+#define UPF_PFCP_LISTEN_DEFAULT "0.0.0.0"
+
+extern struct osmo_tdef_group g_upf_tdef_groups[];
+
+struct pfcp_vty_cfg {
+	char *local_addr;
+	uint16_t local_port;
+};
+
+struct gtp_vty_cfg_dev {
+	struct llist_head entry;
+
+	/* If true, osmo-upf creates the GTP device on startup. If false, the GTP device was created by the user, and we
+	 * just plug into it. */
+	bool create;
+
+	/* GTP device name as shown by 'ip link', e.g. 'apn0' */
+	char *dev_name;
+
+	/* Which address the GTP device should listen on.
+	 * When create == true, the GTP kernel module is created to listen on this address.
+	 * Also used to listen for GTP ECHO requests using libgtp. */
+	char *local_addr;
+};
+
+struct gtp_vty_cfg {
+	/* list of struct gtp_vty_cfg_dev, GTP devices as in the config file. The actual GTP devices in use are in
+	 * g_upf->gtp.devs. */
+	struct llist_head devs;
+};
+
 struct g_upf {
 	struct ctrl_handle *ctrl;
+
+	struct {
+		struct pfcp_vty_cfg vty_cfg;
+		struct up_endpoint *ep;
+	} pfcp;
+	struct {
+		/* GTP devices as in osmo-upf.cfg */
+		struct gtp_vty_cfg vty_cfg;
+
+		/* GTP devices actually in use, list of struct upf_gtp_dev. */
+		struct llist_head devs;
+
+		struct mnl_socket *nl;
+		int32_t genl_id;
+	} gtp;
 };
 
 extern struct g_upf *g_upf;
 
+enum upf_log_subsys {
+	DREF,
+	DPEER,
+	DSESSION,
+	DGTP,
+};
+
 void g_upf_alloc(void *ctx);
+void upf_vty_init();
+int upf_pfcp_listen();
+
+int upf_gtp_devs_open();
+void upf_gtp_devs_close();

include/osmocom/upf/upf_gtp.h

@@ -0,0 +1,85 @@
+/*
+ * (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/linuxlist.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/logging.h>
+
+#define LOG_GTP_DEV(DEV, LEVEL, FMT, ARGS...) \
+	LOGP(DGTP, LEVEL, "%s: " FMT, upf_gtp_dev_to_str_c(OTC_SELECT, (DEV)), ##ARGS)
+
+#define PORT_GTP0_C 3386
+#define PORT_GTP0_U 3386
+
+#define PORT_GTP1_C 2123
+#define PORT_GTP1_U 2152
+
+struct upf_gtp_dev {
+	struct llist_head entry;
+
+	/* If true, osmo-upf created this GTP device on startup and will destroy it on program exit. If false, the user
+	 * has created the device and osmo-upf will not destroy it. */
+	bool created;
+
+	char *name;
+	struct {
+		bool enabled;
+		struct osmo_sockaddr local_addr;
+		struct osmo_fd ofd;
+	} gtpv0;
+	struct {
+		struct osmo_sockaddr local_addr;
+		struct osmo_fd ofd;
+	} gtpv1;
+	bool sgsn_mode;
+
+	uint32_t ifidx;
+
+	struct llist_head tunnels;
+};
+
+struct upf_gtp_tun_desc {
+	uint32_t local_teid;
+	uint32_t remote_teid;
+	struct osmo_sockaddr ue_addr;
+	struct osmo_sockaddr gtp_remote_addr;
+};
+
+int upf_gtp_tun_desc_cmp(const struct upf_gtp_tun_desc *a, const struct upf_gtp_tun_desc *b);
+
+int upf_gtp_genl_open();
+void upf_gtp_genl_close();
+
+int upf_gtp_dev_open(const char *name, bool create_gtp_dev, const char *local_addr, bool listen_for_gtpv0,
+		     bool sgsn_mode);
+struct upf_gtp_dev *upf_gtp_dev_find_by_name(const char *name);
+struct upf_gtp_dev *upf_gtp_dev_first();
+
+int upf_gtp_dev_tunnel_add(struct upf_gtp_dev *dev, const struct upf_gtp_tun_desc *t);
+bool upf_gtp_dev_is_tunnel_active(struct upf_gtp_dev *dev, const struct upf_gtp_tun_desc *t);
+int upf_gtp_dev_tunnel_del(struct upf_gtp_dev *dev, const struct upf_gtp_tun_desc *t);
+
+int upf_gtp_dev_to_str_buf(char *buf, size_t buflen, const struct upf_gtp_dev *dev);
+char *upf_gtp_dev_to_str_c(void *ctx, const struct upf_gtp_dev *dev);

include/osmocom/upf/upf_nft.h

@@ -0,0 +1,48 @@
+/*
+ * (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 <stdint.h>
+
+#include <osmocom/core/socket.h>
+
+struct upf_nft_tunmap_desc {
+	struct {
+		struct osmo_sockaddr gtp_remote_addr;
+		uint32_t local_teid;
+		uint32_t remote_teid;
+	} access;
+	struct {
+		struct osmo_sockaddr gtp_remote_addr;
+		uint32_t local_teid;
+		uint32_t remote_teid;
+	} core;
+	uint32_t id;
+};
+
+int upf_nft_init();
+int upf_nft_free();
+
+int upf_nft_tunmap_create(struct upf_nft_tunmap_desc *tunmap);
+int upf_nft_tunmap_delete(struct upf_nft_tunmap_desc *tunmap);

src/osmo-upf/Makefile.am

@@ -1,6 +1,7 @@
 AM_CPPFLAGS = \
 	$(all_includes) \
 	-I$(top_srcdir)/include \
+	-I$(top_builddir)/include \
 	-I$(top_builddir) \
 	$(NULL)
 
@@ -9,10 +10,14 @@ AM_CFLAGS = \
 	$(LIBOSMOCORE_CFLAGS) \
 	$(LIBOSMOVTY_CFLAGS) \
 	$(LIBOSMOCTRL_CFLAGS) \
+	$(LIBOSMOGTLV_CFLAGS) \
+	$(LIBOSMOPFCP_CFLAGS) \
+	$(LIBGTPNL_CFLAGS) \
 	$(COVERAGE_CFLAGS) \
 	$(NULL)
 
 AM_LDFLAGS = \
+	$(LIBGTPNL_LDFLAGS) \
 	$(COVERAGE_LDFLAGS) \
 	$(NULL)
 
@@ -22,12 +27,21 @@ bin_PROGRAMS = \
 
 osmo_upf_SOURCES = \
 	osmo_upf_main.c \
+	up_endpoint.c \
+	up_gtp_action.c \
+	up_peer.c \
+	up_session.c \
 	upf.c \
+	upf_gtp.c \
+	upf_vty.c \
 	$(NULL)
 
 osmo_upf_LDADD = \
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOVTY_LIBS) \
 	$(LIBOSMOCTRL_LIBS) \
+	$(LIBOSMOGTLV_LIBS) \
+	$(LIBOSMOPFCP_LIBS) \
+	$(LIBGTPNL_LIBS) \
 	$(COVERAGE_LDFLAGS) \
 	$(NULL)

src/osmo-upf/osmo_upf_main.c

@@ -34,11 +34,16 @@
 #include <osmocom/vty/cpu_sched_vty.h>
 #include <osmocom/vty/telnet_interface.h>
 #include <osmocom/vty/ports.h>
+#include <osmocom/vty/tdef_vty.h>
 #include <osmocom/ctrl/control_if.h>
 #include <osmocom/ctrl/control_vty.h>
 #include <osmocom/ctrl/ports.h>
 
+#include <osmocom/pfcp/pfcp_endpoint.h>
+
 #include <osmocom/upf/upf.h>
+#include <osmocom/upf/up_endpoint.h>
+#include <osmocom/upf/upf_gtp.h>
 
 #define _GNU_SOURCE
 #include <getopt.h>
@@ -48,6 +53,7 @@
 
 #include <signal.h>
 #include <stdio.h>
+#include <string.h>
 
 extern void *tall_vty_ctx;
 
@@ -207,6 +213,30 @@ static struct vty_app_info upf_vty_app_info = {
 };
 
 static const struct log_info_cat upf_default_categories[] = {
+	[DREF] = {
+		.name = "DREF",
+		.description = "Reference Counting",
+		.enabled = 0, .loglevel = LOGL_NOTICE,
+		.color = OSMO_LOGCOLOR_DARKGREY,
+	},
+	[DPEER] = {
+		.name = "DPEER",
+		.description = "PFCP peer association",
+		.enabled = 0, .loglevel = LOGL_NOTICE,
+		.color = OSMO_LOGCOLOR_YELLOW,
+	},
+	[DSESSION] = {
+		.name = "DSESSION",
+		.description = "PFCP sessions",
+		.enabled = 0, .loglevel = LOGL_NOTICE,
+		.color = OSMO_LOGCOLOR_BLUE,
+	},
+	[DGTP] = {
+		.name = "DGTP",
+		.description = "GTP tunneling",
+		.enabled = 0, .loglevel = LOGL_NOTICE,
+		.color = OSMO_LOGCOLOR_PURPLE,
+	},
 };
 
 const struct log_info log_info = {
@@ -217,19 +247,27 @@ const struct log_info log_info = {
 int main(int argc, char **argv)
 {
 	int rc;
+	void *tall_infra_ctx;
 
 	/* Track the use of talloc NULL memory contexts */
 	talloc_enable_null_tracking();
 
 	osmo_fsm_set_dealloc_ctx(OTC_SELECT);
 
-	tall_upf_ctx = talloc_named_const(NULL, 1, "osmo-upf");
+	tall_infra_ctx = talloc_named_const(NULL, 1, "osmo-upf");
+	tall_upf_ctx = talloc_named_const(tall_infra_ctx, 1, "osmo-upf-main");
 	upf_vty_app_info.tall_ctx = tall_upf_ctx;
 
 	msgb_talloc_ctx_init(tall_upf_ctx, 0);
 	osmo_signal_talloc_ctx_init(tall_upf_ctx);
 
-	osmo_init_logging2(tall_upf_ctx, &log_info);
+	osmo_init_logging2(tall_infra_ctx, &log_info);
+	log_set_print_category_hex(osmo_stderr_target, 0);
+	log_set_print_category(osmo_stderr_target, 1);
+	log_set_print_level(osmo_stderr_target, 1);
+	log_set_print_filename2(osmo_stderr_target, LOG_FILENAME_BASENAME);
+	log_set_print_filename_pos(osmo_stderr_target, LOG_FILENAME_POS_LINE_END);
+	log_set_print_extended_timestamp(osmo_stderr_target, 1);
 
 	osmo_fsm_log_timeouts(true);
 	osmo_fsm_log_addr(true);
@@ -246,6 +284,9 @@ int main(int argc, char **argv)
 	osmo_talloc_vty_add_cmds();
 	osmo_cpu_sched_vty_init(tall_upf_ctx);
 
+	upf_vty_init();
+	osmo_tdef_vty_groups_init(CONFIG_NODE, g_upf_tdef_groups);
+
 	/* Parse options */
 	handle_options(argc, argv);
 
@@ -283,6 +324,15 @@ int main(int argc, char **argv)
 		}
 	}
 
+	if (upf_gtp_genl_open())
+		return -1;
+
+	if (upf_gtp_devs_open())
+		return -1;
+
+	if (upf_pfcp_listen())
+		return -1;
+
 	do {
 		log_reset_context();
 		osmo_select_main_ctx(0);
@@ -301,12 +351,20 @@ int main(int argc, char **argv)
 		}
 	} while (!osmo_select_shutdown_done());
 
-	log_fini();
+	up_endpoint_free(&g_upf->pfcp.ep);
+	upf_gtp_devs_close();
+
+	upf_gtp_genl_close();
 
 	/* Report the heap state of talloc contexts, then free, so both ASAN and Valgrind are happy... */
 	talloc_report_full(tall_upf_ctx, stderr);
 	talloc_free(tall_upf_ctx);
 
+	log_fini();
+
+	talloc_report_full(tall_infra_ctx, stderr);
+	talloc_free(tall_infra_ctx);
+
 	talloc_report_full(tall_vty_ctx, stderr);
 	talloc_free(tall_vty_ctx);
 

src/osmo-upf/up_endpoint.c

@@ -0,0 +1,322 @@
+/*
+ * (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/>.
+ *
+ */
+
+#include <osmocom/pfcp/pfcp_endpoint.h>
+#include <osmocom/pfcp/pfcp_msg.h>
+
+#include <osmocom/upf/up_endpoint.h>
+#include <osmocom/upf/up_peer.h>
+#include <osmocom/upf/up_session.h>
+
+static void up_endpoint_set_msg_ctx(struct osmo_pfcp_endpoint *ep, struct osmo_pfcp_msg *m, struct osmo_pfcp_msg *req)
+{
+	struct up_endpoint *up_ep = ep->priv;
+	struct up_peer *peer;
+
+	/* If this is a response to an earlier request, just take the msg context from the request message. */
+	if (req) {
+		if (!m->ctx.peer_fi && req->ctx.peer_fi)
+			up_peer_set_msg_ctx(req->ctx.peer_fi->priv, m);
+		if (!m->ctx.session_fi && req->ctx.session_fi)
+			up_session_set_msg_ctx(req->ctx.peer_fi->priv, m);
+	}
+
+	/* From the remote address, find the matching peer instance */
+	if (!m->ctx.peer_fi) {
+		peer = up_peer_find(up_ep, &m->remote_addr);
+		if (peer) {
+			up_peer_set_msg_ctx(peer, m);
+		}
+	} else {
+		peer = m->ctx.peer_fi->priv;
+	}
+
+	/* Find a session, if the header is parsed yet and contains a SEID */
+	if (peer && !m->ctx.session_fi && m->h.seid_present) {
+		struct up_session *session;
+		session = up_session_find_by_up_seid(peer, m->h.seid);
+		if (session) {
+			up_session_set_msg_ctx(session, m);
+		}
+	}
+}
+
+static void up_ep_rx_not_impl_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m,
+				  enum osmo_pfcp_message_type resp_msgt,
+				  const struct osmo_pfcp_ie_node_id *node_id, enum osmo_pfcp_cause cause)
+{
+	struct osmo_pfcp_msg *tx;
+	enum osmo_pfcp_cause *tx_cause;
+	OSMO_LOG_PFCP_MSG(m, LOGL_ERROR, "message type not implemented\n");
+	tx = osmo_pfcp_msg_alloc_tx(OTC_SELECT, NULL, &up_ep->pfcp_ep->cfg.local_node_id, m, resp_msgt);
+	tx_cause = osmo_pfcp_msg_cause(tx);
+	if (tx_cause)
+		*tx_cause = cause;
+	osmo_pfcp_endpoint_tx(up_ep->pfcp_ep, tx);
+}
+
+static void up_ep_rx_pfd_mgmt_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	up_ep_rx_not_impl_req(up_ep, m, OSMO_PFCP_MSGT_PFD_MGMT_RESP, NULL, OSMO_PFCP_CAUSE_SERVICE_NOT_SUPPORTED);
+}
+
+static void up_ep_rx_assoc_setup_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	struct up_peer *peer = m->ctx.peer_fi ? m->ctx.peer_fi->priv : NULL;
+	if (!peer) {
+		peer = up_peer_find_or_add(up_ep, &m->remote_addr);
+		OSMO_ASSERT(peer);
+	}
+	osmo_fsm_inst_dispatch(peer->fi, UP_PEER_EV_RX_ASSOC_SETUP_REQ, (void *)m);
+}
+
+static void up_ep_rx_assoc_upd_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	if (!m->ctx.peer_fi) {
+		struct osmo_pfcp_msg *tx;
+		OSMO_LOG_PFCP_MSG(m, LOGL_ERROR, "Peer is not associated, cannot update association\n");
+		tx = osmo_pfcp_msg_alloc_tx(OTC_SELECT, NULL, &up_ep->pfcp_ep->cfg.local_node_id, m, OSMO_PFCP_MSGT_ASSOC_UPDATE_RESP);
+		/* FIXME set node_id, cause */
+		osmo_pfcp_endpoint_tx(up_ep->pfcp_ep, tx);
+		return;
+	}
+	osmo_fsm_inst_dispatch(m->ctx.peer_fi, UP_PEER_EV_RX_ASSOC_UPD_REQ, (void *)m);
+}
+
+static void up_ep_rx_assoc_rel_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	if (!m->ctx.peer_fi) {
+		struct osmo_pfcp_msg *tx;
+		OSMO_LOG_PFCP_MSG(m, LOGL_ERROR, "Peer is not associated. Sending ACK response anyway\n");
+		tx = osmo_pfcp_msg_alloc_tx(OTC_SELECT, NULL, &up_ep->pfcp_ep->cfg.local_node_id, m, OSMO_PFCP_MSGT_ASSOC_RELEASE_RESP);
+		/* FIXME set node_id, cause */
+		osmo_pfcp_endpoint_tx(up_ep->pfcp_ep, tx);
+		return;
+	}
+	osmo_fsm_inst_dispatch(m->ctx.peer_fi, UP_PEER_EV_RX_ASSOC_REL_REQ, (void *)m);
+}
+
+static void up_ep_rx_node_report_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	up_ep_rx_not_impl_req(up_ep, m, OSMO_PFCP_MSGT_NODE_REPORT_RESP, NULL /* FIXME? */,
+			      OSMO_PFCP_CAUSE_SERVICE_NOT_SUPPORTED);
+}
+
+static void up_ep_rx_session_set_del_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	up_ep_rx_not_impl_req(up_ep, m, OSMO_PFCP_MSGT_SESSION_SET_DEL_RESP,
+			      &up_ep->pfcp_ep->cfg.local_node_id, OSMO_PFCP_CAUSE_SERVICE_NOT_SUPPORTED);
+}
+
+static void up_ep_rx_session_est_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	if (!m->ctx.peer_fi) {
+		struct osmo_pfcp_msg *tx;
+		OSMO_LOG_PFCP_MSG(m, LOGL_ERROR, "Peer is not associated, cannot establish session\n");
+		tx = osmo_pfcp_msg_alloc_tx(OTC_SELECT, NULL, &up_ep->pfcp_ep->cfg.local_node_id, m, OSMO_PFCP_MSGT_SESSION_EST_RESP);
+		tx->ies.session_est_resp.cause = OSMO_PFCP_CAUSE_NO_ESTABLISHED_PFCP_ASSOC;
+		osmo_pfcp_endpoint_tx(up_ep->pfcp_ep, tx);
+		return;
+	}
+	osmo_fsm_inst_dispatch(m->ctx.peer_fi, UP_PEER_EV_RX_SESSION_EST_REQ, (void *)m);
+}
+
+static void up_ep_rx_session_mod_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	if (!m->ctx.session_fi) {
+		/* Session not found. */
+		struct osmo_pfcp_msg *tx;
+		tx = osmo_pfcp_msg_alloc_tx(OTC_SELECT, NULL, &up_ep->pfcp_ep->cfg.local_node_id, m,
+					    OSMO_PFCP_MSGT_SESSION_MOD_RESP);
+		if (!m->ctx.peer_fi) {
+			/* Not even the peer is associated. */
+			OSMO_LOG_PFCP_MSG(m, LOGL_ERROR, "Peer is not associated, cannot modify session\n");
+			tx->ies.session_mod_resp.cause = OSMO_PFCP_CAUSE_NO_ESTABLISHED_PFCP_ASSOC;
+		} else {
+			OSMO_LOG_PFCP_MSG(m, LOGL_ERROR,
+					  "No established session with SEID=0x%"PRIx64", cannot modify\n",
+					  m->h.seid);
+			tx->ies.session_mod_resp.cause = OSMO_PFCP_CAUSE_SESSION_CTX_NOT_FOUND;
+		}
+		osmo_pfcp_endpoint_tx(up_ep->pfcp_ep, tx);
+		return;
+	}
+	osmo_fsm_inst_dispatch(m->ctx.session_fi, UP_SESSION_EV_RX_SESSION_MOD_REQ, (void *)m);
+}
+
+static void up_ep_rx_session_del_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	if (!m->ctx.session_fi) {
+		/* Session not found. */
+		struct osmo_pfcp_msg *tx;
+		tx = osmo_pfcp_msg_alloc_tx(OTC_SELECT, NULL, &up_ep->pfcp_ep->cfg.local_node_id, m, OSMO_PFCP_MSGT_SESSION_DEL_RESP);
+		if (!m->ctx.peer_fi) {
+			/* Not even the peer is associated. */
+			OSMO_LOG_PFCP_MSG(m, LOGL_ERROR, "Peer is not associated, cannot delete session\n");
+			tx->ies.session_del_resp.cause = OSMO_PFCP_CAUSE_NO_ESTABLISHED_PFCP_ASSOC;
+		} else {
+			OSMO_LOG_PFCP_MSG(m, LOGL_ERROR,
+					  "No established session with SEID=0x%"PRIx64", cannot delete\n",
+					  m->h.seid);
+			tx->ies.session_del_resp.cause = OSMO_PFCP_CAUSE_SESSION_CTX_NOT_FOUND;
+		}
+		osmo_pfcp_endpoint_tx(up_ep->pfcp_ep, tx);
+		return;
+	}
+	osmo_fsm_inst_dispatch(m->ctx.session_fi, UP_SESSION_EV_RX_SESSION_DEL_REQ, (void *)m);
+}
+
+static void up_ep_rx_session_rep_req(struct up_endpoint *up_ep, const struct osmo_pfcp_msg *m)
+{
+	up_ep_rx_not_impl_req(up_ep, m, OSMO_PFCP_MSGT_SESSION_REP_RESP, NULL, OSMO_PFCP_CAUSE_SERVICE_NOT_SUPPORTED);
+}
+
+static void up_endpoint_rx_cb(struct osmo_pfcp_endpoint *ep, struct osmo_pfcp_msg *m, struct osmo_pfcp_msg *req)
+{
+	struct up_endpoint *up_ep = ep->priv;
+
+	switch (m->h.message_type) {
+	case OSMO_PFCP_MSGT_PFD_MGMT_REQ:
+		up_ep_rx_pfd_mgmt_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_ASSOC_SETUP_REQ:
+		up_ep_rx_assoc_setup_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_ASSOC_UPDATE_REQ:
+		up_ep_rx_assoc_upd_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_ASSOC_RELEASE_REQ:
+		up_ep_rx_assoc_rel_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_NODE_REPORT_REQ:
+		up_ep_rx_node_report_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_SESSION_SET_DEL_REQ:
+		up_ep_rx_session_set_del_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_SESSION_EST_REQ:
+		up_ep_rx_session_est_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_SESSION_MOD_REQ:
+		up_ep_rx_session_mod_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_SESSION_DEL_REQ:
+		up_ep_rx_session_del_req(up_ep, m);
+		return;
+	case OSMO_PFCP_MSGT_SESSION_REP_REQ:
+		up_ep_rx_session_rep_req(up_ep, m);
+		return;
+	default:
+		OSMO_LOG_PFCP_MSG(m, LOGL_ERROR, "Unknown message type\n");
+		return;
+	}
+}
+
+struct up_endpoint *up_endpoint_init(void *ctx, const struct osmo_sockaddr *local_addr)
+{
+	int rc;
+	struct up_endpoint *up_ep;
+	up_ep = talloc_zero(ctx, struct up_endpoint);
+	INIT_LLIST_HEAD(&up_ep->peers);
+
+	up_ep->pfcp_ep = osmo_pfcp_endpoint_create(up_ep, up_ep);
+	up_ep->pfcp_ep->cfg.local_addr = *local_addr;
+
+	up_ep->pfcp_ep->set_msg_ctx = up_endpoint_set_msg_ctx;
+	up_ep->pfcp_ep->rx_msg = up_endpoint_rx_cb;
+
+	osmo_pfcp_ie_node_id_from_osmo_sockaddr(&up_ep->pfcp_ep->cfg.local_node_id, local_addr);
+
+	rc = osmo_pfcp_endpoint_bind(up_ep->pfcp_ep);
+	if (rc) {
+		talloc_free(up_ep);
+		return NULL;
+	}
+	return up_ep;
+}
+
+static struct up_session *up_endpoint_find_session(struct up_endpoint *ep, uint64_t up_seid)
+{
+		struct up_peer *peer;
+		llist_for_each_entry(peer, &ep->peers, entry) {
+			struct up_session *session = up_session_find_by_up_seid(peer, up_seid);
+			if (session)
+				return session;
+		}
+		return NULL;
+}
+
+static struct up_session *up_endpoint_find_session_by_local_teid(struct up_endpoint *ep, uint32_t teid)
+{
+		struct up_peer *peer;
+		llist_for_each_entry(peer, &ep->peers, entry) {
+			struct up_session *session = up_session_find_by_local_teid(peer, teid);
+			if (session)
+				return session;
+		}
+		return NULL;
+}
+
+uint64_t up_endpoint_next_seid(struct up_endpoint *ep)
+{
+	uint64_t sanity;
+	for (sanity = 2342; sanity; sanity--) {
+		uint64_t next_seid = osmo_pfcp_next_seid(&ep->next_seid_state);
+		if (up_endpoint_find_session(ep, next_seid))
+			continue;
+		return next_seid;
+	}
+	return 0;
+}
+
+static uint32_t up_endpoint_inc_teid(struct up_endpoint *ep)
+{
+	ep->next_teid_state++;
+	if (!ep->next_teid_state)
+		ep->next_teid_state++;
+	return ep->next_teid_state;
+}
+
+uint32_t up_endpoint_next_teid(struct up_endpoint *ep)
+{
+	uint32_t sanity;
+	for (sanity = 2342; sanity; sanity--) {
+		uint32_t next_teid = up_endpoint_inc_teid(ep);
+		if (up_endpoint_find_session_by_local_teid(ep, next_teid))
+			continue;
+		return next_teid;
+	}
+	return 0;
+}
+
+void up_endpoint_free(struct up_endpoint **_ep)
+{
+	struct up_peer *peer;
+	struct up_endpoint *ep = *_ep;
+
+	while ((peer = llist_first_entry_or_null(&ep->peers, struct up_peer, entry)))
+		up_peer_free(peer);
+
+	osmo_pfcp_endpoint_free(&ep->pfcp_ep);
+	*_ep = NULL;
+}

src/osmo-upf/up_gtp_action.c

@@ -0,0 +1,162 @@
+/*
+ * (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/>.
+ *
+ */
+
+#include <errno.h>
+#include <string.h>
+
+#include <osmocom/core/utils.h>
+
+#include <osmocom/upf/upf.h>
+#include <osmocom/upf/up_gtp_action.h>
+#include <osmocom/upf/up_peer.h>
+#include <osmocom/upf/up_session.h>
+
+int up_gtp_action_cmp(const struct up_gtp_action *a, const struct up_gtp_action *b)
+{
+	int cmp;
+	if (a == b)
+		return 0;
+	if (!a)
+		return -1;
+	if (!b)
+		return 1;
+
+#define CMP_MEMB(MEMB) OSMO_CMP(a->MEMB, b->MEMB)
+
+	if ((cmp = CMP_MEMB(kind)))
+		return cmp;
+
+	switch (a->kind) {
+	case UP_GTP_U_ENDECAPS:
+		if ((cmp = CMP_MEMB(endecaps.local_teid)))
+			return cmp;
+		if ((cmp = CMP_MEMB(endecaps.remote_teid)))
+			return cmp;
+		cmp = osmo_sockaddr_cmp(&a->endecaps.gtp_remote_addr, &b->endecaps.gtp_remote_addr);
+		if (cmp)
+			return cmp;
+		cmp = osmo_sockaddr_cmp(&a->endecaps.ue_addr, &b->endecaps.ue_addr);
+		if (cmp)
+			return cmp;
+		break;
+
+	case UP_GTP_U_TUNMAP:
+		if ((cmp = CMP_MEMB(tunmap.access.local_teid)))
+			return cmp;
+		if ((cmp = CMP_MEMB(tunmap.access.remote_teid)))
+			return cmp;
+		if ((cmp = CMP_MEMB(tunmap.core.local_teid)))
+			return cmp;
+		if ((cmp = CMP_MEMB(tunmap.core.remote_teid)))
+			return cmp;
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+static int up_gtp_action_enable_disable(struct up_gtp_action *a, bool enable)
+{
+	struct upf_gtp_dev *gtp_dev;
+	int rc;
+
+	switch (a->kind) {
+	case UP_GTP_U_ENDECAPS:
+		/* use the first available GTP device.
+		 * TODO: select by interface name?
+		 */
+		gtp_dev = upf_gtp_dev_first();
+		if (!gtp_dev) {
+			LOG_UP_GTP_ACTION(a, LOGL_ERROR, "No GTP device open, cannot %s\n", enable ? "enable" : "disable");
+			return -EIO;
+		}
+
+		if (enable)
+			rc = upf_gtp_dev_tunnel_add(gtp_dev, &a->endecaps);
+		else
+			rc = upf_gtp_dev_tunnel_del(gtp_dev, &a->endecaps);
+		if (rc) {
+			LOG_UP_GTP_ACTION(a, LOGL_ERROR, "Failed to %s GTP tunnel: %d %s\n",
+					  enable ? "enable" : "disable", rc, strerror(-rc));
+			return rc;
+		}
+		LOG_UP_GTP_ACTION(a, LOGL_NOTICE, "%s GTP tunnel\n", enable ? "Enabled" : "Disabled");
+		return 0;
+	case UP_GTP_U_TUNMAP:
+		LOG_UP_GTP_ACTION(a, LOGL_ERROR, "TEID translation not yet implemented\n");
+		return -ENOTSUP;
+	default:
+		LOG_UP_GTP_ACTION(a, LOGL_ERROR, "Invalid action\n");
+		return -ENOTSUP;
+	}
+}
+
+int up_gtp_action_enable(struct up_gtp_action *a)
+{
+	return up_gtp_action_enable_disable(a, true);
+}
+
+int up_gtp_action_disable(struct up_gtp_action *a)
+{
+	return up_gtp_action_enable_disable(a, false);
+}
+
+int up_gtp_action_to_str_buf(char *buf, size_t buflen, const struct up_gtp_action *a)
+{
+	struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+	switch (a->kind) {
+	case UP_GTP_U_ENDECAPS:
+		OSMO_STRBUF_PRINTF(sb, "GTP:endecaps GTP-access:");
+		OSMO_STRBUF_APPEND(sb, osmo_sockaddr_to_str_buf2, &a->endecaps.gtp_remote_addr);
+		OSMO_STRBUF_PRINTF(sb, " TEID-r:0x%"PRIx32" TEID-l:0x%"PRIx32" IP-core:",
+				   a->endecaps.remote_teid, a->endecaps.local_teid);
+		OSMO_STRBUF_APPEND(sb, osmo_sockaddr_to_str_buf2, &a->endecaps.ue_addr);
+		break;
+	case UP_GTP_U_TUNMAP:
+		OSMO_STRBUF_PRINTF(sb, "GTP:tunmap GTP-access:");
+		OSMO_STRBUF_APPEND(sb, osmo_sockaddr_to_str_buf2, &a->tunmap.access.gtp_remote_addr);
+		OSMO_STRBUF_PRINTF(sb, " TEID-access-r:0x%"PRIx32" TEID-access-l:0x%"PRIx32" GTP-core:",
+				   a->tunmap.access.remote_teid, a->tunmap.access.local_teid);
+		OSMO_STRBUF_APPEND(sb, osmo_sockaddr_to_str_buf2, &a->tunmap.core.gtp_remote_addr);
+		OSMO_STRBUF_PRINTF(sb, " TEID-core-r:0x%"PRIx32" TEID-core-l:0x%"PRIx32,
+				   a->tunmap.core.remote_teid, a->tunmap.core.local_teid);
+		break;
+	case UP_GTP_DROP:
+		OSMO_STRBUF_PRINTF(sb, "GTP:drop");
+		break;
+	default:
+		OSMO_STRBUF_PRINTF(sb, "GTP:?");
+		break;
+	}
+	if (a->session)
+		OSMO_STRBUF_PRINTF(sb, " PFCP-peer:%s SEID-l:0x%"PRIx64" PDR:%d,%d",
+				   up_peer_remote_addr_str(a->session->up_peer),
+				   a->session->up_seid, a->pdr_core, a->pdr_access);
+	return sb.chars_needed;
+}
+
+char *up_gtp_action_to_str_c(void *ctx, const struct up_gtp_action *a)
+{
+	OSMO_NAME_C_IMPL(ctx, 128, "ERROR", up_gtp_action_to_str_buf, a)
+}

src/osmo-upf/up_peer.c

@@ -0,0 +1,545 @@
+/*
+ * (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/>.
+ *
+ */
+
+#include <errno.h>
+
+#include <osmocom/core/fsm.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/tdef.h>
+#include <osmocom/core/utils.h>
+
+#include <osmocom/pfcp/pfcp_msg.h>
+#include <osmocom/pfcp/pfcp_endpoint.h>
+
+#include <osmocom/upf/upf.h>
+#include <osmocom/upf/up_peer.h>
+#include <osmocom/upf/up_endpoint.h>
+#include <osmocom/upf/up_session.h>
+
+enum up_peer_fsm_state {
+	UP_PEER_ST_NOT_ASSOCIATED,
+	UP_PEER_ST_ASSOCIATED,
+	UP_PEER_ST_GRACEFUL_RELEASE,
+	UP_PEER_ST_WAIT_USE_COUNT,
+};
+
+static const struct value_string up_peer_fsm_event_names[] = {
+	OSMO_VALUE_STRING(UP_PEER_EV_RX_ASSOC_SETUP_REQ),
+	OSMO_VALUE_STRING(UP_PEER_EV_RX_ASSOC_UPD_REQ),
+	OSMO_VALUE_STRING(UP_PEER_EV_RX_ASSOC_REL_REQ),
+	OSMO_VALUE_STRING(UP_PEER_EV_RX_SESSION_EST_REQ),
+	OSMO_VALUE_STRING(UP_PEER_EV_HEARTBEAT_FAILURE),
+	OSMO_VALUE_STRING(UP_PEER_EV_USE_COUNT_ZERO),
+	OSMO_VALUE_STRING(UP_PEER_EV_SESSION_TERM),
+	{}
+};
+
+static struct osmo_fsm up_peer_fsm;
+
+static const struct osmo_tdef_state_timeout up_peer_fsm_timeouts[32] = {
+	[UP_PEER_ST_GRACEFUL_RELEASE] = { .T = -21 },
+};
+
+/* Transition to a state, using the T timer defined in up_peer_fsm_timeouts.
+ * Assumes local variable fi exists. */
+#define up_peer_fsm_state_chg(state) \
+	osmo_tdef_fsm_inst_state_chg(fi, state, \
+				     up_peer_fsm_timeouts, \
+				     osmo_pfcp_tdefs, \
+				     5)
+
+static int up_peer_use_cb(struct osmo_use_count_entry *e, int32_t old_use_count, const char *file, int line)
+{
+	struct up_peer *peer = e->use_count->talloc_object;
+	int32_t total;
+	int level;
+
+	if (!e->use)
+		return -EINVAL;
+
+	total = osmo_use_count_total(&peer->use_count);
+
+	if (total == 0
+	    || (total == 1 && old_use_count == 0 && e->count == 1))
+		level = LOGL_INFO;
+	else
+		level = LOGL_DEBUG;
+
+	LOGPFSMSLSRC(peer->fi, DREF, level, file, line,
+		     "%s %s: now used by %s\n",
+		     (e->count - old_use_count) > 0 ? "+" : "-", e->use,
+		     osmo_use_count_to_str_c(OTC_SELECT, &peer->use_count));
+
+	if (e->count < 0)
+		return -ERANGE;
+
+	if (total == 0)
+		osmo_fsm_inst_dispatch(peer->fi, UP_PEER_EV_USE_COUNT_ZERO, NULL);
+	return 0;
+}
+
+char *up_peer_remote_addr_str(struct up_peer *peer)
+{
+	struct osmo_sockaddr remote_addr = peer->remote_addr;
+
+	/* Zero the port, it is not interesting information. The port for PFCP is defined fixed, and there is no use
+	 * printing it in the logs */
+	osmo_sockaddr_set_port(&remote_addr.u.sa, 0);
+
+	return osmo_sockaddr_to_str_c(OTC_SELECT, &remote_addr);
+}
+
+static void up_peer_update_id(struct up_peer *peer)
+{
+	osmo_fsm_inst_update_id_f_sanitize(peer->fi, '-', "%s", up_peer_remote_addr_str(peer));
+	LOGPFSML(peer->fi, LOGL_DEBUG, "Updated id\n");
+}
+
+static struct up_peer *up_peer_add(struct up_endpoint *up_endpoint, const struct osmo_sockaddr *remote_addr)
+{
+	struct up_peer *peer;
+
+	struct osmo_fsm_inst *fi = osmo_fsm_inst_alloc(&up_peer_fsm, up_endpoint, NULL, LOGL_DEBUG, NULL);
+	OSMO_ASSERT(fi);
+
+	peer = talloc(fi, struct up_peer);
+	OSMO_ASSERT(peer);
+	fi->priv = peer;
+
+	*peer = (struct up_peer) {
+		.fi = fi,
+		.up_endpoint = up_endpoint,
+		.remote_addr = *remote_addr,
+		.heartbeat_fi = NULL /* FIXME */,
+		.use_count = {
+			.talloc_object = peer,
+			.use_cb = up_peer_use_cb,
+		},
+	};
+	osmo_use_count_make_static_entries(&peer->use_count, peer->use_count_buf, ARRAY_SIZE(peer->use_count_buf));
+	hash_init(peer->sessions_by_up_seid);
+	hash_init(peer->sessions_by_cp_seid);
+
+	osmo_pfcp_bits_set(peer->local_up_features.bits, OSMO_PFCP_UP_FEAT_BUNDL, true);
+	osmo_pfcp_bits_set(peer->local_up_features.bits, OSMO_PFCP_UP_FEAT_RTTL, true);
+	osmo_pfcp_bits_set(peer->local_up_features.bits, OSMO_PFCP_UP_FEAT_FTUP, true);
+
+	up_peer_update_id(peer);
+
+	llist_add(&peer->entry, &up_endpoint->peers);
+	return peer;
+}
+
+struct up_peer *up_peer_find(struct up_endpoint *up_endpoint, const struct osmo_sockaddr *remote_addr)
+{
+	struct up_peer *peer;
+	llist_for_each_entry(peer, &up_endpoint->peers, entry) {
+		if (osmo_sockaddr_cmp(&peer->remote_addr, remote_addr))
+			continue;
+		return peer;
+	}
+	return NULL;
+}
+
+struct up_peer *up_peer_find_or_add(struct up_endpoint *up_endpoint, const struct osmo_sockaddr *remote_addr)
+{
+	struct up_peer *peer = up_peer_find(up_endpoint, remote_addr);
+	if (peer)
+		return peer;
+	return up_peer_add(up_endpoint, remote_addr);
+}
+
+int up_peer_tx(struct up_peer *peer, struct osmo_pfcp_msg *m)
+{
+	return osmo_pfcp_endpoint_tx(peer->up_endpoint->pfcp_ep, m);
+}
+
+static int up_peer_fsm_timer_cb(struct osmo_fsm_inst *fi)
+{
+	//struct up_peer *peer = fi->priv;
+	/* Return 1 to terminate FSM instance, 0 to keep running */
+	return 1;
+}
+
+void up_peer_set_msg_ctx(struct up_peer *peer, struct osmo_pfcp_msg *m)
+{
+	OSMO_ASSERT(!m->ctx.peer_fi);
+
+	m->ctx.peer_fi = peer->fi;
+	m->ctx.peer_use_count = &peer->use_count;
+	m->ctx.peer_use_token = (m->rx ? UP_USE_MSG_RX : UP_USE_MSG_TX);
+	osmo_use_count_get_put(m->ctx.peer_use_count, m->ctx.peer_use_token, 1);
+}
+
+struct osmo_pfcp_msg *up_peer_init_tx(struct up_peer *peer, struct osmo_pfcp_msg *in_reply_to,
+				      enum osmo_pfcp_message_type message_type)
+{
+	struct osmo_pfcp_msg *tx = osmo_pfcp_msg_alloc_tx(OTC_SELECT, &peer->remote_addr,
+							  &peer->up_endpoint->pfcp_ep->cfg.local_node_id,
+							  in_reply_to, message_type);
+	up_peer_set_msg_ctx(peer, tx);
+	return tx;
+}
+
+static int up_peer_tx_assoc_setup_resp(struct up_peer *peer, struct osmo_pfcp_msg *m, enum osmo_pfcp_cause cause)
+{
+	struct osmo_pfcp_msg *resp;
+
+	resp = up_peer_init_tx(peer, m, OSMO_PFCP_MSGT_ASSOC_SETUP_RESP);
+
+	resp->ies.assoc_setup_resp = (struct osmo_pfcp_msg_assoc_setup_resp) {
+		.cause = cause,
+		.recovery_time_stamp = g_upf->pfcp.ep->pfcp_ep->recovery_time_stamp,
+		.up_function_features_present = true,
+		.up_function_features = peer->local_up_features,
+	};
+	resp->ies.assoc_setup_resp.recovery_time_stamp = g_upf->pfcp.ep->pfcp_ep->recovery_time_stamp;
+
+	if (osmo_pfcp_endpoint_tx(peer->up_endpoint->pfcp_ep, resp)) {
+		OSMO_LOG_PFCP_MSG(resp, LOGL_ERROR, "Error sending response, cannot associate with peer\n");
+		return -EIO;
+	}
+	return 0;
+}
+
+static int up_peer_tx_assoc_rel_resp(struct up_peer *peer, struct osmo_pfcp_msg *m, enum osmo_pfcp_cause cause)
+{
+	struct osmo_pfcp_msg *resp;
+
+	resp = up_peer_init_tx(peer, m, OSMO_PFCP_MSGT_ASSOC_RELEASE_RESP);
+
+	resp->ies.assoc_release_resp = (struct osmo_pfcp_msg_assoc_release_resp) {
+		.cause = cause,
+	};
+
+	if (osmo_pfcp_endpoint_tx(peer->up_endpoint->pfcp_ep, resp)) {
+		OSMO_LOG_PFCP_MSG(resp, LOGL_ERROR, "Error sending response\n");
+		return -EIO;
+	}
+	return 0;
+}
+
+static void up_peer_clear_sessions(struct up_peer *peer)
+{
+	struct up_session *session;
+	int bkt;
+	struct hlist_node *tmp;
+	int count = 0;
+	hash_for_each_safe(peer->sessions_by_up_seid, bkt, tmp, session, node_by_up_seid) {
+		count += up_session_discard(session);
+	}
+	if (count)
+		LOGPFSML(peer->fi, LOGL_NOTICE, "terminated %d sessions\n", count);
+}
+
+static void up_peer_rx_assoc_setup_req(struct up_peer *peer, struct osmo_pfcp_msg *m)
+{
+	struct osmo_fsm_inst *fi = peer->fi;
+	enum osmo_pfcp_cause cause = OSMO_PFCP_CAUSE_REQUEST_ACCEPTED;
+
+	if (fi->state == UP_PEER_ST_ASSOCIATED) {
+		/* Retransmissions of the ACK response happen in pfcp_endpoint.c. So if we get this, it is a genuine
+		 * duplicate association setup request. We could reject it. But why. Just "replace" with the new
+		 * association. Continue. */
+		/* If the peer has restarted, it has forgotten about all sessions. */
+		if (peer->remote_recovery_timestamp != m->ies.assoc_setup_req.recovery_time_stamp) {
+			LOGPFSML(fi, LOGL_NOTICE, "another Association Setup Request, with different Recovery Timestamp."
+				 " Clearing sessions, sending ACK.\n");
+			up_peer_clear_sessions(peer);
+		} else {
+			LOGPFSML(fi, LOGL_NOTICE, "another Association Setup Request, with same Recovery Timestamp."
+				 " Keeping sessions, sending ACK.\n");
+		}
+	} else if (up_peer_fsm_state_chg(UP_PEER_ST_ASSOCIATED)) {
+		/* Not allowed to transition to ST_ASSOCIATED */
+		cause = OSMO_PFCP_CAUSE_REQUEST_REJECTED;
+	} else {
+		/* Successfully transitioned to ST_ASSOCIATED */
+		peer->remote_recovery_timestamp = m->ies.assoc_setup_req.recovery_time_stamp;
+		peer->remote_node_id = m->ies.assoc_setup_req.node_id;
+		if (m->ies.assoc_setup_req.cp_function_features_present)
+			peer->peer_cp_features = m->ies.assoc_setup_req.cp_function_features;
+	}
+
+	if (up_peer_tx_assoc_setup_resp(peer, m, cause)
+	    || cause != OSMO_PFCP_CAUSE_REQUEST_ACCEPTED)
+		up_peer_fsm_state_chg(UP_PEER_ST_WAIT_USE_COUNT);
+
+	LOGPFSML(fi, LOGL_NOTICE, "Peer associated, Node-Id=%s. Local UP features: [%s]; Peer CP features: [%s]\n",
+		 osmo_pfcp_ie_node_id_to_str_c(OTC_SELECT, &peer->remote_node_id),
+		 osmo_pfcp_bits_to_str_c(OTC_SELECT, peer->local_up_features.bits, osmo_pfcp_up_feature_strs),
+		 osmo_pfcp_bits_to_str_c(OTC_SELECT, peer->peer_cp_features.bits, osmo_pfcp_cp_feature_strs));
+}
+
+static void up_peer_rx_assoc_rel_req(struct up_peer *peer, struct osmo_pfcp_msg *m)
+{
+	struct osmo_fsm_inst *fi = peer->fi;
+	up_peer_tx_assoc_rel_resp(peer, m, OSMO_PFCP_CAUSE_REQUEST_ACCEPTED);
+	up_peer_fsm_state_chg(UP_PEER_ST_WAIT_USE_COUNT);
+}
+
+static void up_peer_rx_session_est_req(struct up_peer *peer, struct osmo_pfcp_msg *m)
+{
+	enum osmo_pfcp_cause cause = OSMO_PFCP_CAUSE_REQUEST_ACCEPTED;
+	struct osmo_pfcp_msg *resp;
+	struct up_session *session = up_session_find_or_add(peer, &m->ies.session_est_req.cp_f_seid, NULL);
+
+	if (!session) {
+		cause = OSMO_PFCP_CAUSE_NO_RESOURCES_AVAILABLE;
+		goto nack_response;
+	}
+
+	up_session_set_msg_ctx(session, m);
+
+	if (osmo_fsm_inst_dispatch(session->fi, UP_SESSION_EV_RX_SESSION_EST_REQ, m)) {
+		cause = OSMO_PFCP_CAUSE_REQUEST_REJECTED;
+		goto nack_response;
+	}
+	return;
+
+nack_response:
+	resp = up_peer_init_tx(peer, m, OSMO_PFCP_MSGT_SESSION_EST_RESP);
+	resp->h.seid = m->ies.session_est_req.cp_f_seid.seid;
+	resp->h.seid_present = true;
+	resp->ies.session_est_resp = (struct osmo_pfcp_msg_session_est_resp){
+		.cause = cause,
+	};
+	osmo_pfcp_endpoint_tx(peer->up_endpoint->pfcp_ep, resp);
+}
+
+static void up_peer_not_associated_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct up_peer *peer = fi->priv;
+
+	switch (event) {
+
+	case UP_PEER_EV_RX_ASSOC_SETUP_REQ:
+		up_peer_rx_assoc_setup_req(peer, data);
+		break;
+
+	case UP_PEER_EV_USE_COUNT_ZERO:
+		/* Not associated and no pending messages. discard peer. */
+		up_peer_fsm_state_chg(UP_PEER_ST_WAIT_USE_COUNT);
+		return;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static void up_peer_associated_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct up_peer *peer = fi->priv;
+
+	switch (event) {
+
+	case UP_PEER_EV_RX_ASSOC_SETUP_REQ:
+		up_peer_rx_assoc_setup_req(peer, data);
+		break;
+
+	case UP_PEER_EV_RX_ASSOC_UPD_REQ:
+		// FIXME
+		break;
+
+	case UP_PEER_EV_RX_SESSION_EST_REQ:
+		up_peer_rx_session_est_req(peer, data);
+		break;
+
+	case UP_PEER_EV_HEARTBEAT_FAILURE:
+		// FIXME
+		break;
+
+	case UP_PEER_EV_USE_COUNT_ZERO:
+		/* Stay associated. */
+		return;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static void up_peer_associated_onleave(struct osmo_fsm_inst *fi, uint32_t next_state)
+{
+	struct up_peer *peer = fi->priv;
+	if (next_state != UP_PEER_ST_ASSOCIATED)
+		LOGPFSML(fi, LOGL_NOTICE, "Peer %s released\n",
+			 osmo_pfcp_ie_node_id_to_str_c(OTC_SELECT, &peer->remote_node_id));
+}
+
+static void up_peer_graceful_release_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	//struct up_peer *peer = fi->priv;
+	// FIXME
+}
+
+static void up_peer_graceful_release_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct up_peer *peer = fi->priv;
+
+	switch (event) {
+
+	case UP_PEER_EV_HEARTBEAT_FAILURE:
+		up_peer_fsm_state_chg(UP_PEER_ST_WAIT_USE_COUNT);
+		break;
+
+	case UP_PEER_EV_USE_COUNT_ZERO:
+		/* When there are still sessions, stay around. */
+		if (!hash_empty(peer->sessions_by_up_seid))
+			return;
+		up_peer_fsm_state_chg(UP_PEER_ST_WAIT_USE_COUNT);
+		return;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static void up_peer_wait_use_count_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct up_peer *peer = fi->priv;
+	up_peer_clear_sessions(peer);
+	if (!osmo_use_count_total(&peer->use_count))
+		osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
+}
+
+static void up_peer_wait_use_count_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct up_peer *peer = fi->priv;
+	switch (event) {
+
+	case UP_PEER_EV_USE_COUNT_ZERO:
+		osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
+		return;
+
+	case UP_PEER_EV_RX_ASSOC_SETUP_REQ:
+		up_peer_rx_assoc_setup_req(peer, data);
+		break;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+#define S(x)    (1 << (x))
+
+static const struct osmo_fsm_state up_peer_fsm_states[] = {
+	[UP_PEER_ST_NOT_ASSOCIATED] = {
+		.name = "NOT_ASSOCIATED",
+		.in_event_mask = 0
+			| S(UP_PEER_EV_RX_ASSOC_SETUP_REQ)
+			| S(UP_PEER_EV_USE_COUNT_ZERO)
+			,
+		.out_state_mask = 0
+			| S(UP_PEER_ST_ASSOCIATED)
+			| S(UP_PEER_ST_WAIT_USE_COUNT)
+			,
+		.action = up_peer_not_associated_action,
+	},
+	[UP_PEER_ST_ASSOCIATED] = {
+		.name = "ASSOCIATED",
+		.in_event_mask = 0
+			| S(UP_PEER_EV_RX_ASSOC_SETUP_REQ)
+			| S(UP_PEER_EV_RX_ASSOC_UPD_REQ)
+			| S(UP_PEER_EV_RX_SESSION_EST_REQ)
+			| S(UP_PEER_EV_HEARTBEAT_FAILURE)
+			| S(UP_PEER_EV_USE_COUNT_ZERO)
+			,
+		.out_state_mask = 0
+			| S(UP_PEER_ST_ASSOCIATED)
+			| S(UP_PEER_ST_GRACEFUL_RELEASE)
+			| S(UP_PEER_ST_WAIT_USE_COUNT)
+			,
+		.action = up_peer_associated_action,
+		.onleave = up_peer_associated_onleave,
+	},
+	[UP_PEER_ST_GRACEFUL_RELEASE] = {
+		.name = "GRACEFUL_RELEASE",
+		.in_event_mask = 0
+			| S(UP_PEER_EV_HEARTBEAT_FAILURE)
+			| S(UP_PEER_EV_USE_COUNT_ZERO)
+			,
+		.out_state_mask = 0
+			| S(UP_PEER_ST_WAIT_USE_COUNT)
+			,
+		.onenter = up_peer_graceful_release_onenter,
+		.action = up_peer_graceful_release_action,
+	},
+	[UP_PEER_ST_WAIT_USE_COUNT] = {
+		.name = "WAIT_USE_COUNT",
+		.in_event_mask = 0
+			| S(UP_PEER_EV_USE_COUNT_ZERO)
+			| S(UP_PEER_EV_RX_ASSOC_SETUP_REQ)
+			,
+		.out_state_mask = 0
+			| S(UP_PEER_ST_ASSOCIATED)
+			,
+		.onenter = up_peer_wait_use_count_onenter,
+		.action = up_peer_wait_use_count_action,
+	},
+};
+
+void up_peer_fsm_cleanup(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
+{
+	struct up_peer *peer = fi->priv;
+	LOGPFSML(fi, LOGL_NOTICE, "Peer removed\n");
+	llist_del(&peer->entry);
+}
+
+static void up_peer_allstate_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case UP_PEER_EV_SESSION_TERM:
+		/* ignore */
+		return;
+	case UP_PEER_EV_RX_ASSOC_REL_REQ:
+		up_peer_rx_assoc_rel_req(fi->priv, data);
+		return;
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static struct osmo_fsm up_peer_fsm = {
+	.name = "up_peer",
+	.log_subsys = DPEER,
+	.states = up_peer_fsm_states,
+	.num_states = ARRAY_SIZE(up_peer_fsm_states),
+	.event_names = up_peer_fsm_event_names,
+	.timer_cb = up_peer_fsm_timer_cb,
+	.cleanup = up_peer_fsm_cleanup,
+	.allstate_event_mask = 0
+		| S(UP_PEER_EV_RX_ASSOC_REL_REQ)
+		| S(UP_PEER_EV_SESSION_TERM)
+		,
+	.allstate_action = up_peer_allstate_action,
+};
+
+static __attribute__((constructor)) void up_peer_fsm_register(void)
+{
+	OSMO_ASSERT(osmo_fsm_register(&up_peer_fsm) == 0);
+}
+
+void up_peer_free(struct up_peer *peer)
+{
+	osmo_fsm_inst_term(peer->fi, OSMO_FSM_TERM_REGULAR, NULL);
+}

src/osmo-upf/up_peer_fsm.c

@@ -0,0 +1,196 @@
+/*
+ * (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/>.
+ *
+ */
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/fsm.h>
+
+#include <osmocom/upf/up_peer.h>
+
+enum up_peer_fsm_state {
+	UP_PEER_ST_NOT_ASSOCIATED,
+	UP_PEER_ST_ASSOCIATED,
+	UP_PEER_ST_GRACEFUL_RELEASE,
+};
+
+static const struct value_string up_peer_fsm_event_names[] = {
+	OSMO_VALUE_STRING(UP_PEER_EV_RX_ASSOC_SETUP_REQ),
+	OSMO_VALUE_STRING(UP_PEER_EV_RX_ASSOC_UPD_REQ),
+	OSMO_VALUE_STRING(UP_PEER_EV_RX_SESSION_EST_REQ),
+	OSMO_VALUE_STRING(UP_PEER_EV_HEARTBEAT_FAILURE),
+	{}
+};
+
+static struct osmo_fsm up_peer_fsm;
+
+static const struct osmo_tdef_state_timeout up_peer_fsm_timeouts[32] = {
+	[UP_PEER_ST_GRACEFUL_RELEASE] = { .T = -21 },
+};
+
+/* Transition to a state, using the T timer defined in up_peer_fsm_timeouts.
+ * Assumes local variable fi exists. */
+#define up_peer_fsm_state_chg(state) \
+	osmo_tdef_fsm_inst_state_chg(fi, state, \
+				     up_peer_fsm_timeouts, \
+				     g_upf_tdefs, \
+				     5)
+
+struct up_peer *up_peer_alloc(struct osmo_fsm_inst *parent_fi, uint32_t parent_event_term)
+{
+	struct up_peer *up_peer;
+
+	struct osmo_fsm_inst *fi = osmo_fsm_inst_alloc_child(&up_peer_fsm, parent_fi, parent_event_term);
+	OSMO_ASSERT(fi);
+
+	up_peer = talloc(fi, struct up_peer);
+	OSMO_ASSERT(up_peer);
+	fi->priv = up_peer;
+	*up_peer = (struct up_peer){
+		.fi = fi,
+	};
+
+	return up_peer;
+}
+
+static int up_peer_fsm_timer_cb(struct osmo_fsm_inst *fi)
+{
+	//struct up_peer *up_peer = fi->priv;
+	/* Return 1 to terminate FSM instance, 0 to keep running */
+	return 1;
+}
+
+static void up_peer_not_associated_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	//struct up_peer *up_peer = fi->priv;
+
+	switch (event) {
+
+	case UP_PEER_EV_RX_ASSOC_SETUP_REQ:
+		// FIXME
+		break;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static void up_peer_associated_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	//struct up_peer *up_peer = fi->priv;
+	// FIXME
+}
+
+static void up_peer_associated_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	//struct up_peer *up_peer = fi->priv;
+
+	switch (event) {
+
+	case UP_PEER_EV_RX_ASSOC_UPD_REQ:
+		// FIXME
+		break;
+
+	case UP_PEER_EV_RX_SESSION_EST_REQ:
+		// FIXME
+		break;
+
+	case UP_PEER_EV_HEARTBEAT_FAILURE:
+		// FIXME
+		break;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static void up_peer_graceful_release_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	//struct up_peer *up_peer = fi->priv;
+	// FIXME
+}
+
+static void up_peer_graceful_release_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	//struct up_peer *up_peer = fi->priv;
+
+	switch (event) {
+
+	case UP_PEER_EV_HEARTBEAT_FAILURE:
+		// FIXME
+		break;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+#define S(x)    (1 << (x))
+
+static const struct osmo_fsm_state up_peer_fsm_states[] = {
+	[UP_PEER_ST_NOT_ASSOCIATED] = {
+		.name = "not_associated",
+		.in_event_mask = 0
+			| S(UP_PEER_EV_RX_ASSOC_SETUP_REQ)
+			,
+		.out_state_mask = 0
+			| S(UP_PEER_ST_ASSOCIATED)
+			,
+		.action = up_peer_not_associated_action,
+	},
+	[UP_PEER_ST_ASSOCIATED] = {
+		.name = "associated",
+		.in_event_mask = 0
+			| S(UP_PEER_EV_RX_ASSOC_UPD_REQ)
+			| S(UP_PEER_EV_RX_SESSION_EST_REQ)
+			| S(UP_PEER_EV_HEARTBEAT_FAILURE)
+			,
+		.out_state_mask = 0
+			| S(UP_PEER_ST_GRACEFUL_RELEASE)
+			,
+		.onenter = up_peer_associated_onenter,
+		.action = up_peer_associated_action,
+	},
+	[UP_PEER_ST_GRACEFUL_RELEASE] = {
+		.name = "graceful_release",
+		.in_event_mask = 0
+			| S(UP_PEER_EV_HEARTBEAT_FAILURE)
+			,
+		.out_state_mask = 0
+			,
+		.onenter = up_peer_graceful_release_onenter,
+		.action = up_peer_graceful_release_action,
+	},
+};
+
+static struct osmo_fsm up_peer_fsm = {
+	.name = "up_peer",
+	.states = up_peer_fsm_states,
+	.num_states = ARRAY_SIZE(up_peer_fsm_states),
+	.log_subsys = DSESSION,
+	.event_names = up_peer_fsm_event_names,
+	.timer_cb = up_peer_fsm_timer_cb,
+};
+
+static __attribute__((constructor)) void up_peer_fsm_register(void)
+{
+	OSMO_ASSERT(osmo_fsm_register(&up_peer_fsm) == 0);
+}

src/osmo-upf/upf.c

@@ -23,13 +23,69 @@
 
 #include <osmocom/core/utils.h>
 #include <osmocom/core/talloc.h>
+#include <osmocom/core/sockaddr_str.h>
+
+#include <osmocom/pfcp/pfcp_endpoint.h>
 
 #include <osmocom/upf/upf.h>
+#include <osmocom/upf/up_endpoint.h>
+#include <osmocom/upf/upf_gtp.h>
 
 struct g_upf *g_upf = NULL;
 
+struct osmo_tdef_group g_upf_tdef_groups[] = {
+	{ "pfcp", "PFCP endpoint timers", osmo_pfcp_tdefs, },
+	{}
+};
+
 void g_upf_alloc(void *ctx)
 {
 	OSMO_ASSERT(g_upf == NULL);
 	g_upf = talloc_zero(ctx, struct g_upf);
+
+	*g_upf = (struct g_upf){
+		.pfcp = {
+			.vty_cfg = {
+				.local_addr = talloc_strdup(g_upf, UPF_PFCP_LISTEN_DEFAULT),
+				.local_port = OSMO_PFCP_PORT,
+			},
+		},
+	};
+
+	INIT_LLIST_HEAD(&g_upf->gtp.vty_cfg.devs);
+	INIT_LLIST_HEAD(&g_upf->gtp.devs);
+}
+
+int upf_pfcp_listen()
+{
+	struct osmo_sockaddr_str local_addr_str;
+	struct osmo_sockaddr local_addr;
+
+	OSMO_ASSERT(g_upf);
+	OSMO_ASSERT(g_upf->pfcp.ep == NULL);
+
+	/* Translate address string from VTY config to osmo_sockaddr: first read into osmo_sockaddr_str, then write to
+	 * osmo_sockaddr. */
+	osmo_sockaddr_str_from_str(&local_addr_str, g_upf->pfcp.vty_cfg.local_addr, g_upf->pfcp.vty_cfg.local_port);
+	osmo_sockaddr_str_to_sockaddr(&local_addr_str, &local_addr.u.sas);
+	LOGP(DLPFCP, LOGL_NOTICE, "PFCP: Listening on %s\n", osmo_sockaddr_to_str_c(OTC_SELECT, &local_addr));
+
+	g_upf->pfcp.ep = up_endpoint_init(g_upf, &local_addr);
+	if (!g_upf->pfcp.ep) {
+		fprintf(stderr, "Failed to allocate PFCP endpoint.\n");
+		return -1;
+	}
+	return 0;
+}
+
+int upf_gtp_devs_open()
+{
+	struct gtp_vty_cfg *c = &g_upf->gtp.vty_cfg;
+	struct gtp_vty_cfg_dev *d;
+
+	llist_for_each_entry(d, &c->devs, entry) {
+		if (upf_gtp_dev_open(d->dev_name, d->create, d->local_addr, false, false))
+			return -1;
+	}
+	return 0;
 }

src/osmo-upf/upf_gtp.c

@@ -0,0 +1,457 @@
+/*
+ * (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/>.
+ *
+ */
+
+#include <stdbool.h>
+#include <errno.h>
+#include <string.h>
+#include <net/if.h>
+#include <linux/gtp.h>
+
+#include <libgtpnl/gtpnl.h>
+#include <libgtpnl/gtp.h>
+
+#include <osmocom/core/socket.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/sockaddr_str.h>
+
+#include <osmocom/upf/upf.h>
+#include <osmocom/upf/upf_gtp.h>
+
+#define LOG_GTP_TUN(TUN, LEVEL, FMT, ARGS...) \
+	LOGP(DGTP, LEVEL, "%s: " FMT, upf_gtp_tun_to_str_c(OTC_SELECT, (TUN)), ##ARGS)
+
+int upf_gtp_dev_to_str_buf(char *buf, size_t buflen, const struct upf_gtp_dev *dev)
+{
+	uint16_t v0_port;
+	struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+	OSMO_STRBUF_PRINTF(sb, "%s", dev->name ? : "null");
+	if (dev->name && dev->ifidx)
+		OSMO_STRBUF_PRINTF(sb, " [%u]", dev->ifidx);
+	if (dev->sgsn_mode)
+		OSMO_STRBUF_PRINTF(sb, " (SGSN)");
+	OSMO_STRBUF_PRINTF(sb, " ");
+	OSMO_STRBUF_APPEND(sb, osmo_sockaddr_to_str_buf2, &dev->gtpv1.local_addr);
+	v0_port = osmo_sockaddr_port(&dev->gtpv0.local_addr.u.sa);
+	if (dev->gtpv0.enabled && v0_port)
+		OSMO_STRBUF_PRINTF(sb, "/%u", v0_port);
+	return sb.chars_needed;
+}
+
+char *upf_gtp_dev_to_str_c(void *ctx, const struct upf_gtp_dev *dev)
+{
+	OSMO_NAME_C_IMPL(ctx, 64, "ERROR", upf_gtp_dev_to_str_buf, dev)
+}
+
+struct upf_gtp_dev *upf_gtp_dev_find_by_name(const char *name)
+{
+	struct upf_gtp_dev *dev;
+	llist_for_each_entry(dev, &g_upf->gtp.devs, entry) {
+		if (!strcmp(name, dev->name))
+			return dev;
+	}
+	return NULL;
+}
+
+struct upf_gtp_dev *upf_gtp_dev_first()
+{
+	return llist_first_entry_or_null(&g_upf->gtp.devs, struct upf_gtp_dev, entry);
+}
+
+/* Tell the kernel to remove the GTP device. Called implicitly by talloc_free() (see upf_gtp_dev_destruct()). */
+static int upf_gtp_dev_delete(struct upf_gtp_dev *dev)
+{
+	int rc;
+	if (!dev->name)
+		return 0;
+	rc = gtp_dev_destroy(dev->name);
+	if (rc < 0) {
+		LOG_GTP_DEV(dev, LOGL_ERROR, "Error while deleting device: %s\n", strerror(errno));
+		return rc;
+	}
+	LOG_GTP_DEV(dev, LOGL_NOTICE, "Deleted GTP device\n");
+	dev->name = NULL;
+	return 0;
+}
+
+static int upf_gtp_dev_destruct(struct upf_gtp_dev *dev);
+
+static struct upf_gtp_dev *upf_gtp_dev_alloc(const char *name, const char *local_addr)
+{
+	struct upf_gtp_dev *dev = upf_gtp_dev_find_by_name(name);
+	struct osmo_sockaddr_str addr_conv;
+	local_addr = local_addr ? : "0.0.0.0";
+	if (dev) {
+		LOG_GTP_DEV(dev, LOGL_ERROR, "Device already exists. Cannot create %s %s\n", name, local_addr);
+		return NULL;
+	}
+	dev = talloc(g_upf, struct upf_gtp_dev);
+	*dev = (struct upf_gtp_dev){
+		.name = talloc_strdup(dev, name),
+		.gtpv0.ofd.fd = -1,
+		.gtpv1.ofd.fd = -1,
+	};
+	INIT_LLIST_HEAD(&dev->tunnels);
+
+	osmo_sockaddr_str_from_str(&addr_conv, local_addr, PORT_GTP0_U);
+
+	osmo_sockaddr_str_to_sockaddr(&addr_conv, &dev->gtpv0.local_addr.u.sas);
+
+	addr_conv.port = PORT_GTP1_U;
+	osmo_sockaddr_str_to_sockaddr(&addr_conv, &dev->gtpv1.local_addr.u.sas);
+
+	/* Need to add to list before setting up the destructor. A talloc_free() does automagically remove from the
+	 * list. */
+	llist_add(&dev->entry, &g_upf->gtp.devs);
+
+	talloc_set_destructor(dev, upf_gtp_dev_destruct);
+
+	return dev;
+}
+
+static int dev_resolve_ifidx(struct upf_gtp_dev *dev)
+{
+	int rc;
+
+	dev->ifidx = if_nametoindex(dev->name);
+	if (dev->ifidx == 0) {
+		LOG_GTP_DEV(dev, LOGL_ERROR, "No such device: '%s'\n", dev->name);
+		talloc_free(dev);
+		return -EIO;
+	}
+	/* Let's try something to see if talking to the device works. */
+	errno = 0;
+	rc = gtp_list_tunnel(g_upf->gtp.genl_id, g_upf->gtp.nl);
+	if (errno)
+		rc = -errno;
+	else if (rc)
+		rc = -EINVAL;
+	if (rc) {
+		LOG_GTP_DEV(dev, LOGL_ERROR, "Failed to open GTP device: %s\n", strerror(-rc));
+		talloc_free(dev);
+		return rc;
+	}
+
+	LOG_GTP_DEV(dev, LOGL_NOTICE, "GTP device ready (ifidx=%u)\n", dev->ifidx);
+	return 0;
+}
+
+int upf_gtp_dev_open(const char *name, bool create_gtp_dev, const char *local_addr, bool listen_for_gtpv0, bool sgsn_mode)
+{
+	struct osmo_sockaddr any = {
+		.u.sin = {
+			.sin_family = AF_INET,
+			.sin_port = 0,
+			.sin_addr = {
+				.s_addr = INADDR_ANY,
+			},
+		},
+	};
+	int rc;
+	struct upf_gtp_dev *dev = upf_gtp_dev_alloc(name, local_addr);
+	if (!dev)
+		return -EIO;
+
+	dev->sgsn_mode = sgsn_mode;
+
+	if (listen_for_gtpv0) {
+		rc = osmo_sock_init_osa_ofd(&dev->gtpv0.ofd, SOCK_DGRAM, 0, &dev->gtpv0.local_addr, &any,
+					    OSMO_SOCK_F_BIND);
+		if (rc < 0) {
+			LOG_GTP_DEV(dev, LOGL_ERROR, "Cannot bind GTPv0 on %s (rc=%d)\n",
+				    osmo_sockaddr_to_str_c(OTC_SELECT, &dev->gtpv0.local_addr), rc);
+			talloc_free(dev);
+			return -EIO;
+		}
+		dev->gtpv0.enabled = true;
+		LOG_GTP_DEV(dev, LOGL_DEBUG, "GTPv0 bound\n");
+	}
+
+	/* GTPv1 */
+	rc = osmo_sock_init_osa_ofd(&dev->gtpv1.ofd, SOCK_DGRAM, 0, &dev->gtpv1.local_addr, &any,
+				    OSMO_SOCK_F_BIND);
+	if (rc < 0) {
+		LOG_GTP_DEV(dev, LOGL_ERROR, "Cannot bind GTPv1 (rc=%d)\n", rc);
+		talloc_free(dev);
+		return -EIO;
+	}
+	LOG_GTP_DEV(dev, LOGL_DEBUG, "GTPv1 bound\n");
+
+	if (create_gtp_dev) {
+		int gtp0_fd = listen_for_gtpv0 ? dev->gtpv0.ofd.fd : -1;
+		int gtp1_fd = dev->gtpv1.ofd.fd;
+		if (dev->sgsn_mode)
+			rc = gtp_dev_create_sgsn(-1, dev->name, gtp0_fd, gtp1_fd);
+		else
+			rc = gtp_dev_create(-1, dev->name, gtp0_fd, gtp1_fd);
+		if (rc < 0) {
+			LOG_GTP_DEV(dev, LOGL_ERROR, "Cannot create GTP device: rc=%d\n", rc);
+			/* name = NULL: signal to the destructor that it does not need to delete the device */
+			dev->name = NULL;
+			talloc_free(dev);
+			return -EIO;
+		}
+
+		LOG_GTP_DEV(dev, LOGL_NOTICE, "created GTP device\n");
+		dev->created = true;
+	}
+
+	rc = dev_resolve_ifidx(dev);
+	if (rc) {
+		talloc_free(dev);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+void upf_gtp_devs_close()
+{
+	struct upf_gtp_dev *dev;
+	while ((dev = llist_first_entry_or_null(&g_upf->gtp.devs, struct upf_gtp_dev, entry)))
+		talloc_free(dev);
+}
+
+void upf_gtp_genl_close()
+{
+	if (!g_upf->gtp.nl)
+		return;
+	genl_socket_close(g_upf->gtp.nl);
+	g_upf->gtp.nl = NULL;
+	g_upf->gtp.genl_id = -1;
+
+	LOGP(DGTP, LOGL_NOTICE, "Closed mnl_socket\n");
+}
+
+/* Open an MNL socket which allows to create and remove GTP devices (requires CAP_NET_ADMIN). */
+int upf_gtp_genl_open()
+{
+	if (g_upf->gtp.nl && g_upf->gtp.genl_id >= 0)
+		return 0;
+
+	if (g_upf->gtp.nl)
+		upf_gtp_genl_close();
+
+	g_upf->gtp.nl = genl_socket_open();
+	if (!g_upf->gtp.nl) {
+		LOGP(DGTP, LOGL_ERROR, "Cannot open mnl_socket: %s\n", strerror(errno));
+		return -EIO;
+	}
+
+	g_upf->gtp.genl_id = genl_lookup_family(g_upf->gtp.nl, "gtp");
+	if (g_upf->gtp.genl_id < 0) {
+		LOGP(DGTP, LOGL_ERROR, "genl family 'gtp' not found\n");
+		return -ENOTSUP;
+	}
+
+	LOGP(DGTP, LOGL_NOTICE, "Opened mnl_socket\n");
+	return 0;
+}
+
+struct upf_gtp_tun {
+	struct llist_head entry;
+
+	struct upf_gtp_dev *dev;
+	struct upf_gtp_tun_desc desc;
+	bool active;
+};
+
+static int upf_gtp_tun_to_str_buf(char *buf, size_t buflen, const struct upf_gtp_tun *tun)
+{
+	struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+	OSMO_STRBUF_PRINTF(sb, "%s:tun{TEID=l:0x%x,r:0x%x UE=", tun->dev->name, tun->desc.local_teid,
+			   tun->desc.remote_teid);
+	OSMO_STRBUF_APPEND(sb, osmo_sockaddr_to_str_buf2, &tun->desc.ue_addr);
+	OSMO_STRBUF_PRINTF(sb, " GTP-dst=");
+	OSMO_STRBUF_APPEND(sb, osmo_sockaddr_to_str_buf2, &tun->desc.gtp_remote_addr);
+	OSMO_STRBUF_PRINTF(sb, "}");
+	return sb.chars_needed;
+}
+
+static char *upf_gtp_tun_to_str_c(void *ctx, const struct upf_gtp_tun *tun)
+{
+	OSMO_NAME_C_IMPL(ctx, 64, "ERROR", upf_gtp_tun_to_str_buf, tun)
+}
+
+static int upf_gtp_tun_deactivate(struct upf_gtp_tun *tun);
+
+static int upf_gtp_tun_destruct(struct upf_gtp_tun *tun)
+{
+	if (tun->active)
+		upf_gtp_tun_deactivate(tun);
+	llist_del(&tun->entry);
+	return 0;
+}
+
+static struct upf_gtp_tun *upf_gtp_tun_alloc(struct upf_gtp_dev *dev, const struct upf_gtp_tun_desc *desc)
+{
+	struct upf_gtp_tun *tun = talloc(dev, struct upf_gtp_tun);
+	OSMO_ASSERT(tun);
+	*tun = (struct upf_gtp_tun){
+		.dev = dev,
+		.desc = *desc,
+	};
+	llist_add(&tun->entry, &dev->tunnels);
+	talloc_set_destructor(tun, upf_gtp_tun_destruct);
+	return tun;
+}
+
+static struct gtp_tunnel *upf_gtp_tun_to_gtp_tunnel(struct upf_gtp_tun *tun)
+{
+	struct gtp_tunnel *t;
+
+	if (tun->desc.ue_addr.u.sas.ss_family != AF_INET || tun->desc.gtp_remote_addr.u.sas.ss_family != AF_INET) {
+		LOG_GTP_TUN(tun, LOGL_ERROR, "Only capabale of IPv4\n");
+		return NULL;
+	}
+
+	t = gtp_tunnel_alloc();
+	OSMO_ASSERT(t);
+	gtp_tunnel_set_ifidx(t, tun->dev->ifidx);
+	gtp_tunnel_set_version(t, GTP_V1);
+	gtp_tunnel_set_i_tei(t, tun->desc.local_teid);
+	gtp_tunnel_set_o_tei(t, tun->desc.remote_teid);
+	gtp_tunnel_set_ms_ip4(t, &tun->desc.ue_addr.u.sin.sin_addr);
+	gtp_tunnel_set_sgsn_ip4(t, &tun->desc.gtp_remote_addr.u.sin.sin_addr);
+	return t;
+}
+
+int upf_gtp_tun_activate(struct upf_gtp_tun *tun)
+{
+	int rc;
+	struct gtp_tunnel *t;
+
+	if (tun->active)
+		return -EALREADY;
+
+	t = upf_gtp_tun_to_gtp_tunnel(tun);
+	if (!t)
+		return -ENOTSUP;
+
+	errno = 0;
+	rc = gtp_add_tunnel(g_upf->gtp.genl_id, g_upf->gtp.nl, t);
+	if (errno) {
+		rc = -errno;
+	} else if (rc) {
+		rc = -EINVAL;
+	} else {
+		tun->active = true;
+	}
+
+	gtp_tunnel_free(t);
+	return rc;
+}
+
+static struct upf_gtp_tun *upf_gtp_dev_tunnel_find(struct upf_gtp_dev *dev, const struct upf_gtp_tun_desc *tun_desc)
+{
+	struct upf_gtp_tun *tun;
+	llist_for_each_entry(tun, &dev->tunnels, entry) {
+		if (upf_gtp_tun_desc_cmp(tun_desc, &tun->desc))
+			continue;
+		return tun;
+	}
+	return NULL;
+}
+
+int upf_gtp_dev_tunnel_add(struct upf_gtp_dev *dev, const struct upf_gtp_tun_desc *tun_desc)
+{
+	struct upf_gtp_tun *tun;
+	tun = upf_gtp_dev_tunnel_find(dev, tun_desc);
+	if (!tun)
+		tun = upf_gtp_tun_alloc(dev, tun_desc);
+	if (tun->active)
+		return 0;
+	return upf_gtp_tun_activate(tun);
+}
+
+int upf_gtp_dev_tunnel_del(struct upf_gtp_dev *dev, const struct upf_gtp_tun_desc *tun_desc)
+{
+	struct upf_gtp_tun *tun;
+	int rc;
+	tun = upf_gtp_dev_tunnel_find(dev, tun_desc);
+	if (!tun)
+		return 0;
+	if (tun->active) {
+		rc = upf_gtp_tun_deactivate(tun);
+		if (rc)
+			return rc;
+	}
+	talloc_free(tun);
+	return 0;
+}
+
+static int upf_gtp_tun_deactivate(struct upf_gtp_tun *tun)
+{
+	int rc;
+	struct gtp_tunnel *t;
+
+	if (!tun->active) {
+		LOG_GTP_TUN(tun, LOGL_ERROR, "Cannot deactivate, not active\n");
+		return -EINVAL;
+	}
+
+	t = upf_gtp_tun_to_gtp_tunnel(tun);
+	if (!t)
+		return -EINVAL;
+
+	rc = gtp_del_tunnel(g_upf->gtp.genl_id, g_upf->gtp.nl, t);
+	if (rc)
+		LOG_GTP_TUN(tun, LOGL_ERROR, "Failed to delete tunnel: %d %s\n", rc, strerror(rc));
+	else
+		tun->active = false;
+
+	gtp_tunnel_free(t);
+	return rc;
+}
+
+static int upf_gtp_dev_destruct(struct upf_gtp_dev *dev)
+{
+	struct upf_gtp_tun *t;
+	/* Destruct and clean up all active tunnels before deleting the device */
+	while ((t = llist_first_entry_or_null(&dev->tunnels, struct upf_gtp_tun, entry)))
+		talloc_free(t);
+	llist_del(&dev->entry);
+	osmo_fd_close(&dev->gtpv0.ofd);
+	osmo_fd_close(&dev->gtpv1.ofd);
+	if (dev->created)
+		upf_gtp_dev_delete(dev);
+	return 0;
+}
+
+int upf_gtp_tun_desc_cmp(const struct upf_gtp_tun_desc *a, const struct upf_gtp_tun_desc *b)
+{
+	int r;
+
+	if (a == b)
+		return 0;
+	if (!a)
+		return -1;
+	if (!b)
+		return 1;
+
+#define CMP_MEMB(MEMB) OSMO_CMP(a->MEMB, b->MEMB)
+	if ((r = CMP_MEMB(local_teid)))
+		return r;
+	if ((r = CMP_MEMB(remote_teid)))
+		return r;
+	return osmo_sockaddr_cmp(&a->gtp_remote_addr, &b->gtp_remote_addr);
+}

src/osmo-upf/upf_vty.c

@@ -0,0 +1,286 @@
+/* OsmoUpf interface to quagga VTY */
+/*
+ * (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/>.
+ *
+ */
+
+#include <osmocom/core/sockaddr_str.h>
+#include <osmocom/core/socket.h>
+
+#include <osmocom/pfcp/pfcp_endpoint.h>
+#include <osmocom/pfcp/pfcp_msg.h>
+
+#include <osmocom/vty/vty.h>
+#include <osmocom/vty/command.h>
+
+#include <osmocom/upf/upf.h>
+#include <osmocom/upf/upf_gtp.h>
+#include <osmocom/upf/up_endpoint.h>
+#include <osmocom/upf/up_peer.h>
+#include <osmocom/upf/up_session.h>
+#include <osmocom/upf/up_gtp_action.h>
+
+enum upf_vty_node {
+	PFCP_NODE = _LAST_OSMOVTY_NODE + 1,
+	GTP_NODE,
+};
+
+static struct cmd_node cfg_pfcp_node = {
+	PFCP_NODE,
+	"%s(config-pfcp)# ",
+	1,
+};
+
+#define pfcp_vty (g_upf->pfcp.vty_cfg)
+#define gtp_vty (g_upf->gtp.vty_cfg)
+
+DEFUN(cfg_pfcp, cfg_pfcp_cmd,
+      "pfcp",
+      "Enter the PFCP configuration node\n")
+{
+	vty->node = PFCP_NODE;
+	return CMD_SUCCESS;
+}
+
+static int config_write_pfcp(struct vty *vty)
+{
+	vty_out(vty, "pfcp%s", VTY_NEWLINE);
+	if (strcmp(UPF_PFCP_LISTEN_DEFAULT, pfcp_vty.local_addr))
+		vty_out(vty, " local-addr %s%s", pfcp_vty.local_addr, VTY_NEWLINE);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_pfcp_local_addr, cfg_pfcp_local_addr_cmd,
+      "local-addr IP_ADDR",
+      "Set the local IP address to bind on for PFCP\n"
+      "IP address\n")
+{
+	osmo_talloc_replace_string(g_upf, &pfcp_vty.local_addr, argv[0]);
+	return CMD_SUCCESS;
+}
+
+static struct cmd_node cfg_gtp_node = {
+	GTP_NODE,
+	"%s(config-gtp)# ",
+	1,
+};
+
+DEFUN(cfg_gtp, cfg_gtp_cmd,
+      "gtp",
+      "Enter the GTP configuration node\n")
+{
+	vty->node = GTP_NODE;
+	return CMD_SUCCESS;
+}
+
+static int config_write_gtp(struct vty *vty)
+{
+	struct gtp_vty_cfg_dev *d;
+	vty_out(vty, "gtp%s", VTY_NEWLINE);
+
+	llist_for_each_entry(d, &gtp_vty.devs, entry) {
+		if (d->create) {
+			vty_out(vty, " dev create %s", d->dev_name);
+			if (d->local_addr)
+				vty_out(vty, " %s", d->local_addr);
+			vty_out(vty, "%s", VTY_NEWLINE);
+		} else {
+			vty_out(vty, " dev use %s%s", d->dev_name, VTY_NEWLINE);
+		}
+	}
+	return CMD_SUCCESS;
+}
+
+#define DEV_STR "Configure the GTP device to use for encaps/decaps.\n"
+
+DEFUN(cfg_gtp_dev_create, cfg_gtp_dev_create_cmd,
+      "dev create DEVNAME [LISTEN_ADDR]",
+      DEV_STR
+      "create a new GTP device. Will listen on GTPv1 port " OSMO_STRINGIFY_VAL(PORT_GTP1_U)
+      " and GTPv0 port " OSMO_STRINGIFY_VAL(PORT_GTP0_U) " on the specified interface, or on ANY if LISTEN_ADDR is"
+      " omitted.\n"
+      "device name, e.g. 'apn0'\n"
+      "IPv4 or IPv6 address to listen on, omit for ANY\n")
+{
+	struct gtp_vty_cfg_dev *d = talloc_zero(g_upf, struct gtp_vty_cfg_dev);
+	d->create = true;
+	d->dev_name = talloc_strdup(d, argv[0]);
+	if (argc > 1)
+		d->local_addr = talloc_strdup(d, argv[1]);
+	llist_add(&d->entry, &gtp_vty.devs);
+	vty_out(vty, "Added GTP device %s (create new)%s", d->dev_name, VTY_NEWLINE);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_gtp_dev_use, cfg_gtp_dev_use_cmd,
+      "dev use DEVNAME",
+      DEV_STR
+      "use an existing GTP device, e.g. created by 'gtp-link'\n"
+      "device name, e.g. 'apn0'\n")
+{
+	struct gtp_vty_cfg_dev *d = talloc_zero(g_upf, struct gtp_vty_cfg_dev);
+	d->create = false;
+	d->dev_name = talloc_strdup(d, argv[0]);
+	llist_add(&d->entry, &gtp_vty.devs);
+	vty_out(vty, "Added GTP device %s (use existing)%s", d->dev_name, VTY_NEWLINE);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_gtp_dev_del, cfg_gtp_dev_del_cmd,
+      "dev delete DEVNAME",
+      DEV_STR
+      "Remove a GTP device from the configuration, and delete the device if it was created here.\n"
+      "device name, e.g. 'apn0'\n")
+{
+	const char *dev_name = argv[0];
+	struct gtp_vty_cfg_dev *d;
+	struct upf_gtp_dev *dev;
+
+	/* remove from VTY cfg */
+	llist_for_each_entry(d, &gtp_vty.devs, entry) {
+		if (strcmp(d->dev_name, dev_name))
+			continue;
+		llist_del(&d->entry);
+		break;
+	}
+
+	/* close device (and possibly delete from system, via talloc destructor) */
+	dev = upf_gtp_dev_find_by_name(dev_name);
+	if (dev)
+		talloc_free(dev);
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_pdr, show_pdr_cmd,
+      "show pdr",
+      SHOW_STR
+      "List all sessions' PDR and FAR status\n")
+{
+	struct up_peer *peer;
+	int active_count = 0;
+	int inactive_count = 0;
+	llist_for_each_entry(peer, &g_upf->pfcp.ep->peers, entry) {
+		struct up_session *session;
+		int bkt;
+		hash_for_each(peer->sessions_by_up_seid, bkt, session, node_by_up_seid) {
+			struct pdr *pdr;
+			llist_for_each_entry(pdr, &session->pdrs, entry) {
+				if (!pdr->active) {
+					vty_out(vty, "%s: inactive: %s%s%s%s",
+						session->fi->id, pdr_to_str_c(OTC_SELECT, pdr),
+						pdr->inactive_reason ? ": " : "",
+						pdr->inactive_reason ? : "",
+						VTY_NEWLINE);
+					inactive_count++;
+				} else {
+					vty_out(vty, "%s: active: %s%s",
+						session->fi->id, pdr_to_str_c(OTC_SELECT, pdr),
+						VTY_NEWLINE);
+					active_count++;
+				}
+			}
+		}
+	}
+	vty_out(vty, "(%d of %d active)%s", active_count, active_count + inactive_count, VTY_NEWLINE);
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_gtp, show_gtp_cmd,
+      "show gtp",
+      SHOW_STR
+      "Active GTP tunnels and forwardings\n")
+{
+	struct up_peer *peer;
+	int count = 0;
+
+	if (!upf_gtp_dev_first()) {
+		vty_out(vty, "No GTP device open%s", VTY_NEWLINE);
+		return CMD_SUCCESS;
+	}
+
+	llist_for_each_entry(peer, &g_upf->pfcp.ep->peers, entry) {
+		struct up_session *session;
+		int bkt;
+		hash_for_each(peer->sessions_by_up_seid, bkt, session, node_by_up_seid) {
+			struct up_gtp_action *a;
+			llist_for_each_entry(a, &session->active_gtp_actions, entry) {
+				vty_out(vty, "%s%s", up_gtp_action_to_str_c(OTC_SELECT, a), VTY_NEWLINE);
+				count++;
+			}
+		}
+	}
+	vty_out(vty, "(%d active)%s", count, VTY_NEWLINE);
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_session, show_session_cmd,
+      "show session",
+      SHOW_STR
+      "PFCP Session status\n")
+{
+	struct up_peer *peer;
+	int inactive_count = 0;
+	int active_count = 0;
+	int fully_active_count = 0;
+
+	llist_for_each_entry(peer, &g_upf->pfcp.ep->peers, entry) {
+		struct up_session *session;
+		int bkt;
+		hash_for_each(peer->sessions_by_up_seid, bkt, session, node_by_up_seid) {
+			vty_out(vty, "%s %s%s",
+				up_session_to_str_c(OTC_SELECT, session),
+				up_session_gtp_status(session), VTY_NEWLINE);
+			if (up_session_is_active(session)) {
+				if (up_session_is_fully_active(session, NULL, NULL))
+					fully_active_count++;
+				else
+					active_count++;
+			} else {
+				inactive_count++;
+			}
+		}
+	}
+	vty_out(vty, "(%d fully-active + %d partially active + %d inactive)%s",
+		fully_active_count, active_count, inactive_count, VTY_NEWLINE);
+	return CMD_SUCCESS;
+}
+
+void upf_vty_init()
+{
+	OSMO_ASSERT(g_upf != NULL);
+
+	install_element_ve(&show_pdr_cmd);
+	install_element_ve(&show_gtp_cmd);
+	install_element_ve(&show_session_cmd);
+
+	install_node(&cfg_pfcp_node, config_write_pfcp);
+	install_element(CONFIG_NODE, &cfg_pfcp_cmd);
+
+	install_element(PFCP_NODE, &cfg_pfcp_local_addr_cmd);
+
+	install_node(&cfg_gtp_node, config_write_gtp);
+	install_element(CONFIG_NODE, &cfg_gtp_cmd);
+
+	install_element(GTP_NODE, &cfg_gtp_dev_create_cmd);
+	install_element(GTP_NODE, &cfg_gtp_dev_use_cmd);
+	install_element(GTP_NODE, &cfg_gtp_dev_del_cmd);
+}
+

tests/upf.vty

@@ -2,3 +2,34 @@ OsmoUPF> enable
 OsmoUPF# configure terminal
 OsmoUPF(config)# show running-config
 ...
+
+OsmoUPF(config)# pfcp
+OsmoUPF(config-pfcp)# list
+...
+  local-addr IP_ADDR
+OsmoUPF(config-pfcp)# local-addr?
+  local-addr  Set the local IP address to bind on for PFCP
+OsmoUPF(config-pfcp)# local-addr ?
+  IP_ADDR  IP address
+OsmoUPF(config-pfcp)# exit
+
+OsmoUPF(config)# gtp
+OsmoUPF(config-gtp)# list
+...
+  dev create DEVNAME [LISTEN_ADDR]
+  dev use DEVNAME
+  dev delete DEVNAME
+
+OsmoUPF(config-gtp)# dev?
+  dev  Configure the GTP device to use for encaps/decaps.
+OsmoUPF(config-gtp)# dev ?
+  create  create a new GTP device. Will listen on GTPv1 port 2152 and GTPv0 port 3386 on the specified interface, or on ANY if LISTEN_ADDR is omitted.
+  use     use an existing GTP device, e.g. created by 'gtp-link'
+  delete  Remove a GTP device from the configuration, and delete the device if it was created here.
+OsmoUPF(config-gtp)# dev create ?
+  DEVNAME  device name, e.g. 'apn0'
+OsmoUPF(config-gtp)# dev create foo ?
+  [LISTEN_ADDR]  IPv4 or IPv6 address to listen on, omit for ANY
+OsmoUPF(config-gtp)# dev delete ?
+  DEVNAME  device name, e.g. 'apn0'
+OsmoUPF(config-gtp)# exit