add generic PFCP CP peer implementation0.1.0

Will be used by osmo-hnbgw, our first PFCP Control Plane entity. The
implementation is generic enough that it can be re-used by other CP
entities.

Related: SYS#5895
Change-Id: If8c5f69f596ea6ba8bd1723f4dc57b91d3799795

4 files changed, 469 insertions, 0 deletions

diff --git a/include/osmocom/pfcp/Makefile.am b/include/osmocom/pfcp/Makefile.am
index 5d2db19..898113f 100644
--- a/include/osmocom/pfcp/Makefile.am
+++ b/include/osmocom/pfcp/Makefile.am
@@ -5,6 +5,7 @@ pfcp_HEADERS = \
 	pfcp_msg.h \
 	pfcp_proto.h \
 	pfcp_strs.h \
+	pfcp_cp_peer.h \
 	$(NULL)
 
 pfcpdir = $(includedir)/osmocom/pfcp
diff --git a/include/osmocom/pfcp/pfcp_cp_peer.h b/include/osmocom/pfcp/pfcp_cp_peer.h
new file mode 100644
index 0000000..8c6e448
--- /dev/null
+++ b/include/osmocom/pfcp/pfcp_cp_peer.h
@@ -0,0 +1,63 @@
+/*
+ * (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 <stdbool.h>
+
+#include <osmocom/core/socket.h>
+#include <osmocom/core/use_count.h>
+#include <osmocom/pfcp/pfcp_proto.h>
+
+struct osmo_fsm_inst;
+struct osmo_pfcp_endpoint;
+struct osmo_pfcp_cp_peer;
+
+typedef void (*osmo_pfcp_cp_peer_assoc_cb)(struct osmo_pfcp_cp_peer *cp_peer, bool associated);
+
+struct osmo_pfcp_cp_peer {
+	struct osmo_fsm_inst *fi;
+	struct osmo_pfcp_endpoint *ep;
+	struct osmo_sockaddr remote_addr;
+	uint64_t next_seid_state;
+
+	/* If non-NULL, called whenever the peer completes a PFCP Association, and when it loses association.
+	 * Argument associated == true means the peer has just associated;
+	 * associated == false means the association has been lost. */
+	osmo_pfcp_cp_peer_assoc_cb assoc_cb;
+	/* Application private data for assoc_cb, in case ep->priv does not suffice. */
+	void *priv;
+
+	struct osmo_use_count use_count;
+	struct osmo_use_count_entry use_count_buf[128];
+};
+
+struct osmo_pfcp_cp_peer *osmo_pfcp_cp_peer_alloc(void *ctx,
+						  struct osmo_pfcp_endpoint *ep,
+						  const struct osmo_sockaddr *remote_addr);
+int osmo_pfcp_cp_peer_associate(struct osmo_pfcp_cp_peer *cp_peer);
+bool osmo_pfcp_cp_peer_is_associated(const struct osmo_pfcp_cp_peer *cp_peer);
+struct osmo_pfcp_msg *osmo_pfcp_cp_peer_new_msg_tx(struct osmo_pfcp_cp_peer *cp_peer,
+						   enum osmo_pfcp_message_type msg_type);
+void osmo_pfcp_cp_peer_set_msg_ctx(struct osmo_pfcp_cp_peer *cp_peer, struct osmo_pfcp_msg *m);
diff --git a/src/libosmo-pfcp/Makefile.am b/src/libosmo-pfcp/Makefile.am
index 1f4b80f..a1e9904 100644
--- a/src/libosmo-pfcp/Makefile.am
+++ b/src/libosmo-pfcp/Makefile.am
@@ -28,6 +28,7 @@ libosmo_pfcp_la_SOURCES = \
 	pfcp_ies_custom.c \
 	pfcp_msg.c \
 	pfcp_strs.c \
+	pfcp_cp_peer.c \
 	\
 	pfcp_ies_auto.c \
 	$(NULL)
diff --git a/src/libosmo-pfcp/pfcp_cp_peer.c b/src/libosmo-pfcp/pfcp_cp_peer.c
new file mode 100644
index 0000000..c47b440
--- /dev/null
+++ b/src/libosmo-pfcp/pfcp_cp_peer.c
@@ -0,0 +1,404 @@
+/*
+ * (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/utils.h>
+#include <osmocom/core/fsm.h>
+#include <osmocom/core/tdef.h>
+
+#include <osmocom/pfcp/pfcp_endpoint.h>
+#include <osmocom/pfcp/pfcp_cp_peer.h>
+
+#define LOG_CP_PEER(CP_PEER, LOGLEVEL, FMT, ARGS...) \
+	LOGPFSML((CP_PEER)->fi, LOGLEVEL, FMT, ##ARGS)
+
+enum pfcp_cp_peer_fsm_state {
+	PFCP_CP_PEER_ST_DISABLED,
+	PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP,
+	PFCP_CP_PEER_ST_WAIT_RETRY,
+	PFCP_CP_PEER_ST_ASSOCIATED,
+	PFCP_CP_PEER_ST_GRACEFUL_RELEASE,
+	PFCP_CP_PEER_ST_WAIT_USE_COUNT,
+};
+
+enum pfcp_cp_peer_fsm_event {
+	PFCP_CP_PEER_EV_RX_ASSOC_SETUP_RESP,
+	PFCP_CP_PEER_EV_RX_ASSOC_UPDATE_REQ,
+	PFCP_CP_PEER_EV_USE_COUNT_ZERO,
+};
+
+static const struct value_string pfcp_cp_peer_fsm_event_names[] = {
+	OSMO_VALUE_STRING(PFCP_CP_PEER_EV_RX_ASSOC_SETUP_RESP),
+	OSMO_VALUE_STRING(PFCP_CP_PEER_EV_RX_ASSOC_UPDATE_REQ),
+	OSMO_VALUE_STRING(PFCP_CP_PEER_EV_USE_COUNT_ZERO),
+	{}
+};
+
+static struct osmo_fsm pfcp_cp_peer_fsm;
+
+static const struct osmo_tdef_state_timeout pfcp_cp_peer_fsm_timeouts[32] = {
+	[PFCP_CP_PEER_ST_WAIT_RETRY] = { .T = -26 },
+	/* PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP is terminated by the on_pfcp_assoc_resp() callback */
+	[PFCP_CP_PEER_ST_GRACEFUL_RELEASE] = { .T = -21 },
+};
+
+/* Transition to a state, using the T timer defined in pfcp_cp_peer_fsm_timeouts.
+ * Assumes local variable fi exists. */
+#define osmo_pfcp_cp_peer_fsm_state_chg(state) \
+       osmo_tdef_fsm_inst_state_chg(fi, state, \
+				    pfcp_cp_peer_fsm_timeouts, \
+				    osmo_pfcp_tdefs, \
+				    5)
+
+static int pfcp_cp_peer_use_cb(struct osmo_use_count_entry *e, int32_t old_use_count, const char *file, int line)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = e->use_count->talloc_object;
+
+	if (!e->use)
+		return -EINVAL;
+
+	LOGPFSMSLSRC(cp_peer->fi, DLPFCP, LOGL_DEBUG, file, line,
+		     "%s %s: now used by %s\n",
+		     e->count > old_use_count ? "+" : "-", e->use,
+		     osmo_use_count_to_str_c(OTC_SELECT, &cp_peer->use_count));
+
+	if (e->count < 0)
+		return -ERANGE;
+
+	if (osmo_use_count_total(&cp_peer->use_count) == 0)
+		osmo_fsm_inst_dispatch(cp_peer->fi, PFCP_CP_PEER_EV_USE_COUNT_ZERO, NULL);
+	return 0;
+}
+
+/* Allocate PFCP CP peer FSM and start sending PFCP Association Setup Request messages to remote_addr, using endpoint
+ * ep. As soon as a successful response is received, change to state PFCP_CP_PEER_ST_ASSOCIATED.
+ */
+struct osmo_pfcp_cp_peer *osmo_pfcp_cp_peer_alloc(void *ctx,
+						  struct osmo_pfcp_endpoint *ep,
+						  const struct osmo_sockaddr *remote_addr)
+{
+	struct osmo_pfcp_cp_peer *cp_peer;
+	struct osmo_fsm_inst *fi = osmo_fsm_inst_alloc(&pfcp_cp_peer_fsm, ctx, NULL, LOGL_DEBUG, NULL);
+	OSMO_ASSERT(fi);
+
+	cp_peer = talloc(fi, struct osmo_pfcp_cp_peer);
+	OSMO_ASSERT(cp_peer);
+	fi->priv = cp_peer;
+	*cp_peer = (struct osmo_pfcp_cp_peer){
+		.fi = fi,
+		.ep = ep,
+		.remote_addr = *remote_addr,
+		.use_count = {
+			.talloc_object = cp_peer,
+			.use_cb = pfcp_cp_peer_use_cb,
+		},
+	};
+	osmo_use_count_make_static_entries(&cp_peer->use_count, cp_peer->use_count_buf, ARRAY_SIZE(cp_peer->use_count_buf));
+
+	osmo_fsm_inst_update_id_f_sanitize(fi, '-', osmo_sockaddr_to_str_c(OTC_SELECT, &cp_peer->remote_addr));
+	return cp_peer;
+}
+
+int osmo_pfcp_cp_peer_associate(struct osmo_pfcp_cp_peer *cp_peer)
+{
+	struct osmo_fsm_inst *fi = cp_peer->fi;
+
+	switch (fi->state) {
+	case PFCP_CP_PEER_ST_DISABLED:
+	case PFCP_CP_PEER_ST_WAIT_RETRY:
+		/* Idling. Send Association Setup Request now. */
+		return osmo_pfcp_cp_peer_fsm_state_chg(PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP);
+	default:
+		/* Already associated, or busy associating. */
+		return 0;
+	case PFCP_CP_PEER_ST_WAIT_USE_COUNT:
+		/* Already asked to deallocate. */
+		return -ENOLINK;
+	}
+	return 0;
+}
+
+static int pfcp_cp_peer_fsm_timer_cb(struct osmo_fsm_inst *fi)
+{
+	switch (fi->state) {
+
+	case PFCP_CP_PEER_ST_WAIT_RETRY:
+		osmo_pfcp_cp_peer_fsm_state_chg(PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP);
+		return 0;
+
+	default:
+		return 1;
+	}
+}
+
+static int on_pfcp_assoc_resp(struct osmo_pfcp_msg *req, struct osmo_pfcp_msg *rx_resp, const char *errmsg);
+
+/* Send PFCP Association Setup Request */
+static void pfcp_cp_peer_wait_assoc_setup_resp_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+	struct osmo_pfcp_msg *m;
+
+	m = osmo_pfcp_cp_peer_new_msg_tx(cp_peer, OSMO_PFCP_MSGT_ASSOC_SETUP_REQ);
+	m->ies.assoc_setup_req.recovery_time_stamp = cp_peer->ep->recovery_time_stamp;
+
+	m->ies.assoc_setup_req.cp_function_features_present = true;
+	osmo_pfcp_bits_set(m->ies.assoc_setup_req.cp_function_features.bits, OSMO_PFCP_CP_FEAT_BUNDL, true);
+
+	m->ctx.resp_cb = on_pfcp_assoc_resp;
+
+	LOG_CP_PEER(cp_peer, LOGL_NOTICE, "Associating with %s...\n",
+		    osmo_sockaddr_to_str_c(OTC_SELECT, &cp_peer->remote_addr));
+
+	if (osmo_pfcp_endpoint_tx(cp_peer->ep, m)) {
+		LOG_CP_PEER(cp_peer, LOGL_ERROR, "Failed to transmit PFCP Association Setup Request to UPF at %s\n",
+			    osmo_sockaddr_to_str_c(OTC_SELECT, &cp_peer->remote_addr));
+		osmo_pfcp_cp_peer_fsm_state_chg(PFCP_CP_PEER_ST_WAIT_RETRY);
+	}
+}
+
+static int on_pfcp_assoc_resp(struct osmo_pfcp_msg *req, struct osmo_pfcp_msg *rx_resp, const char *errmsg)
+{
+	struct osmo_fsm_inst *fi = req->ctx.peer_fi;
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+	enum osmo_pfcp_cause *cause;
+
+	if (!rx_resp) {
+		LOG_CP_PEER(cp_peer, LOGL_ERROR, "Error: PFCP Association Setup Response: %s\n",
+			    errmsg ? : "no response received");
+		goto assoc_failed;
+	}
+
+	cause = osmo_pfcp_msg_cause(rx_resp);
+	if (!cause) {
+		LOG_CP_PEER(cp_peer, LOGL_ERROR, "Invalid PFCP Association Setup Response: no Cause value\n");
+		goto assoc_failed;
+	}
+	if (*cause != OSMO_PFCP_CAUSE_REQUEST_ACCEPTED) {
+		LOG_CP_PEER(cp_peer, LOGL_ERROR, "UPF rejected PFCP Association Setup Request with Cause: %s\n",
+			    osmo_pfcp_cause_str(*cause));
+		goto assoc_failed;
+	}
+
+	osmo_fsm_inst_dispatch(fi, PFCP_CP_PEER_EV_RX_ASSOC_SETUP_RESP, rx_resp);
+	return 0;
+
+assoc_failed:
+	osmo_pfcp_cp_peer_fsm_state_chg(PFCP_CP_PEER_ST_WAIT_RETRY);
+	return 0;
+}
+
+static void pfcp_cp_peer_wait_assoc_setup_resp_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+
+	case PFCP_CP_PEER_EV_RX_ASSOC_SETUP_RESP:
+		osmo_pfcp_cp_peer_fsm_state_chg(PFCP_CP_PEER_ST_ASSOCIATED);
+		break;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static void pfcp_cp_peer_associated_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+	LOG_CP_PEER(cp_peer, LOGL_NOTICE, "Associated with UPF %s\n",
+		    osmo_sockaddr_to_str_c(OTC_SELECT, &cp_peer->remote_addr));
+	if (cp_peer->assoc_cb)
+		cp_peer->assoc_cb(cp_peer, true);
+}
+
+static void pfcp_cp_peer_associated_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+
+	switch (event) {
+
+	case PFCP_CP_PEER_EV_RX_ASSOC_UPDATE_REQ:
+		LOG_CP_PEER(cp_peer, LOGL_ERROR, "PFCP Association Update Request is not implemented\n");
+		break;
+
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+static void pfcp_cp_peer_associated_onleave(struct osmo_fsm_inst *fi, uint32_t next_state)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+	LOG_CP_PEER(cp_peer, LOGL_NOTICE, "Disassociating from UPF %s\n",
+		    osmo_sockaddr_to_str_c(OTC_SELECT, &cp_peer->remote_addr));
+	if (cp_peer->assoc_cb)
+		cp_peer->assoc_cb(cp_peer, false);
+}
+
+static void pfcp_cp_peer_graceful_release_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+	LOG_CP_PEER(cp_peer, LOGL_ERROR, "PFCP graceful release is not implemented\n");
+}
+
+static void pfcp_cp_peer_graceful_release_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+	LOG_CP_PEER(cp_peer, LOGL_ERROR, "PFCP graceful release is not implemented\n");
+}
+
+static void pfcp_cp_peer_wait_use_count_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state)
+{
+	struct osmo_pfcp_cp_peer *cp_peer = fi->priv;
+	if (!osmo_use_count_total(&cp_peer->use_count))
+		osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
+}
+
+static void pfcp_cp_peer_allstate_action(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case PFCP_CP_PEER_EV_USE_COUNT_ZERO:
+		switch (fi->state) {
+		default:
+			/* still busy, ignore. */
+			return;
+		case PFCP_CP_PEER_ST_WAIT_USE_COUNT:
+			/* Waiting for deallocation; now there are no more users, deallocate. */
+			osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REGULAR, NULL);
+			return;
+		}
+	default:
+		OSMO_ASSERT(false);
+	}
+}
+
+#define S(x) (1 << (x))
+
+static const struct osmo_fsm_state pfcp_cp_peer_fsm_states[] = {
+	[PFCP_CP_PEER_ST_DISABLED] = {
+		.name = "disabled",
+		.out_state_mask = 0
+			| S(PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP)
+			| S(PFCP_CP_PEER_ST_WAIT_USE_COUNT)
+			,
+	},
+	[PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP] = {
+		.name = "wait_assoc_setup_resp",
+		.in_event_mask = 0
+			| S(PFCP_CP_PEER_EV_RX_ASSOC_SETUP_RESP)
+			,
+		.out_state_mask = 0
+			| S(PFCP_CP_PEER_ST_ASSOCIATED)
+			| S(PFCP_CP_PEER_ST_WAIT_RETRY)
+			| S(PFCP_CP_PEER_ST_WAIT_USE_COUNT)
+			,
+		.onenter = pfcp_cp_peer_wait_assoc_setup_resp_onenter,
+		.action = pfcp_cp_peer_wait_assoc_setup_resp_action,
+	},
+	[PFCP_CP_PEER_ST_WAIT_RETRY] = {
+		.name = "wait_retry",
+		.out_state_mask = 0
+			| S(PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP)
+			| S(PFCP_CP_PEER_ST_WAIT_USE_COUNT)
+			,
+	},
+	[PFCP_CP_PEER_ST_ASSOCIATED] = {
+		.name = "associated",
+		.in_event_mask = 0
+			| S(PFCP_CP_PEER_EV_RX_ASSOC_UPDATE_REQ)
+			,
+		.out_state_mask = 0
+			| S(PFCP_CP_PEER_ST_WAIT_ASSOC_SETUP_RESP)
+			| S(PFCP_CP_PEER_ST_GRACEFUL_RELEASE)
+			| S(PFCP_CP_PEER_ST_WAIT_USE_COUNT)
+			,
+		.onenter = pfcp_cp_peer_associated_onenter,
+		.action = pfcp_cp_peer_associated_action,
+		.onleave = pfcp_cp_peer_associated_onleave,
+	},
+	[PFCP_CP_PEER_ST_GRACEFUL_RELEASE] = {
+		.name = "graceful_release",
+		.in_event_mask = 0
+			,
+		.out_state_mask = 0
+			| S(PFCP_CP_PEER_ST_WAIT_RETRY)
+			| S(PFCP_CP_PEER_ST_WAIT_USE_COUNT)
+			,
+		.onenter = pfcp_cp_peer_graceful_release_onenter,
+		.action = pfcp_cp_peer_graceful_release_action,
+	},
+	[PFCP_CP_PEER_ST_WAIT_USE_COUNT] = {
+		.name = "wait_use_count",
+		.in_event_mask = 0
+			| S(PFCP_CP_PEER_EV_USE_COUNT_ZERO)
+			,
+		.onenter = pfcp_cp_peer_wait_use_count_onenter,
+	},
+};
+
+static struct osmo_fsm pfcp_cp_peer_fsm = {
+	.name = "pfcp_cp_peer",
+	.states = pfcp_cp_peer_fsm_states,
+	.num_states = ARRAY_SIZE(pfcp_cp_peer_fsm_states),
+	.log_subsys = DLPFCP,
+	.event_names = pfcp_cp_peer_fsm_event_names,
+	.timer_cb = pfcp_cp_peer_fsm_timer_cb,
+	.allstate_action = pfcp_cp_peer_allstate_action,
+	.allstate_event_mask = 0
+		| S(PFCP_CP_PEER_EV_USE_COUNT_ZERO)
+		,
+};
+
+static __attribute__((constructor)) void pfcp_cp_peer_fsm_register(void)
+{
+	OSMO_ASSERT(osmo_fsm_register(&pfcp_cp_peer_fsm) == 0);
+}
+
+bool osmo_pfcp_cp_peer_is_associated(const struct osmo_pfcp_cp_peer *cp_peer)
+{
+	return cp_peer && cp_peer->fi->state == PFCP_CP_PEER_ST_ASSOCIATED;
+}
+
+void osmo_pfcp_cp_peer_set_msg_ctx(struct osmo_pfcp_cp_peer *cp_peer, struct osmo_pfcp_msg *m)
+{
+	if (m->ctx.peer_fi)
+		return;
+
+	m->ctx.peer_fi = cp_peer->fi;
+
+	m->ctx.peer_use_count = &cp_peer->use_count;
+	m->ctx.peer_use_token = (m->rx ? "PFCPrx" : "PFCPtx");
+	osmo_use_count_get_put(m->ctx.peer_use_count, m->ctx.peer_use_token, 1);
+}
+
+struct osmo_pfcp_msg *osmo_pfcp_cp_peer_new_msg_tx(struct osmo_pfcp_cp_peer *cp_peer,
+						   enum osmo_pfcp_message_type msg_type)
+{
+	struct osmo_pfcp_msg *m;
+	m = osmo_pfcp_msg_alloc_tx(cp_peer->ep, &cp_peer->remote_addr, &cp_peer->ep->cfg.local_node_id, NULL,
+				   msg_type);
+	if (!m)
+		return m;
+	osmo_pfcp_cp_peer_set_msg_ctx(cp_peer, m);
+	return m;
+}