tipc: enable tracepoints in tipc

As for the sake of debugging/tracing, the commit enables tracepoints in
TIPC along with some general trace_events as shown below. It also
defines some 'tipc_*_dump()' functions that allow to dump TIPC object
data whenever needed, that is, for general debug purposes, ie. not just
for the trace_events.

The following trace_events are now available:

- trace_tipc_skb_dump(): allows to trace and dump TIPC msg & skb data,
  e.g. message type, user, droppable, skb truesize, cloned skb, etc.

- trace_tipc_list_dump(): allows to trace and dump any TIPC buffers or
  queues, e.g. TIPC link transmq, socket receive queue, etc.

- trace_tipc_sk_dump(): allows to trace and dump TIPC socket data, e.g.
  sk state, sk type, connection type, rmem_alloc, socket queues, etc.

- trace_tipc_link_dump(): allows to trace and dump TIPC link data, e.g.
  link state, silent_intv_cnt, gap, bc_gap, link queues, etc.

- trace_tipc_node_dump(): allows to trace and dump TIPC node data, e.g.
  node state, active links, capabilities, link entries, etc.

How to use:
Put the trace functions at any places where we want to dump TIPC data
or events.

Note:
a) The dump functions will generate raw data only, that is, to offload
the trace event's processing, it can require a tool or script to parse
the data but this should be simple.

b) The trace_tipc_*_dump() should be reserved for a failure cases only
(e.g. the retransmission failure case) or where we do not expect to
happen too often, then we can consider enabling these events by default
since they will almost not take any effects under normal conditions,
but once the rare condition or failure occurs, we get the dumped data
fully for post-analysis.

For other trace purposes, we can reuse these trace classes as template
but different events.

c) A trace_event is only effective when we enable it. To enable the
TIPC trace_events, echo 1 to 'enable' files in the events/tipc/
directory in the 'debugfs' file system. Normally, they are located at:

/sys/kernel/debug/tracing/events/tipc/

For example:

To enable the tipc_link_dump event:

echo 1 > /sys/kernel/debug/tracing/events/tipc/tipc_link_dump/enable

To enable all the TIPC trace_events:

echo 1 > /sys/kernel/debug/tracing/events/tipc/enable

To collect the trace data:

cat trace

or

cat trace_pipe > /trace.out &

To disable all the TIPC trace_events:

echo 0 > /sys/kernel/debug/tracing/events/tipc/enable

To clear the trace buffer:

echo > trace

d) Like the other trace_events, the feature like 'filter' or 'trigger'
is also usable for the tipc trace_events.
For more details, have a look at:

Documentation/trace/ftrace.txt

MAINTAINERS | add two new files 'trace.h' & 'trace.c' in tipc
Acked-by: Ying Xue <ying.xue@windriver.com>
Tested-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/Makefile

@@ -9,7 +9,9 @@ tipc-y	+= addr.o bcast.o bearer.o \
 	   core.o link.o discover.o msg.o  \
 	   name_distr.o  subscr.o monitor.o name_table.o net.o  \
 	   netlink.o netlink_compat.o node.o socket.o eth_media.o \
-	   topsrv.o socket.o group.o
+	   topsrv.o socket.o group.o trace.o
+
+CFLAGS_trace.o += -I$(src)
 
 tipc-$(CONFIG_TIPC_MEDIA_UDP)	+= udp_media.o
 tipc-$(CONFIG_TIPC_MEDIA_IB)	+= ib_media.o

net/tipc/bearer.c

@@ -99,7 +99,7 @@ static struct tipc_media *media_find_id(u8 type)
 /**
  * tipc_media_addr_printf - record media address in print buffer
  */
-void tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a)
+int tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a)
 {
 	char addr_str[MAX_ADDR_STR];
 	struct tipc_media *m;
@@ -114,9 +114,10 @@ void tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a)
 
 		ret = scnprintf(buf, len, "UNKNOWN(%u)", a->media_id);
 		for (i = 0; i < sizeof(a->value); i++)
-			ret += scnprintf(buf - ret, len + ret,
-					    "-%02x", a->value[i]);
+			ret += scnprintf(buf + ret, len - ret,
+					    "-%x", a->value[i]);
 	}
+	return ret;
 }
 
 /**

net/tipc/bearer.h

@@ -207,7 +207,7 @@ int __tipc_nl_media_set(struct sk_buff *skb, struct genl_info *info);
 
 int tipc_media_set_priority(const char *name, u32 new_value);
 int tipc_media_set_window(const char *name, u32 new_value);
-void tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a);
+int tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a);
 int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b,
 			 struct nlattr *attrs[]);
 void tipc_disable_l2_media(struct tipc_bearer *b);

net/tipc/link.c

@@ -43,6 +43,7 @@
 #include "discover.h"
 #include "netlink.h"
 #include "monitor.h"
+#include "trace.h"
 
 #include <linux/pkt_sched.h>
 
@@ -2222,3 +2223,122 @@ void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
 {
 	l->abort_limit = limit;
 }
+
+char *tipc_link_name_ext(struct tipc_link *l, char *buf)
+{
+	if (!l)
+		scnprintf(buf, TIPC_MAX_LINK_NAME, "null");
+	else if (link_is_bc_sndlink(l))
+		scnprintf(buf, TIPC_MAX_LINK_NAME, "broadcast-sender");
+	else if (link_is_bc_rcvlink(l))
+		scnprintf(buf, TIPC_MAX_LINK_NAME,
+			  "broadcast-receiver, peer %x", l->addr);
+	else
+		memcpy(buf, l->name, TIPC_MAX_LINK_NAME);
+
+	return buf;
+}
+
+/**
+ * tipc_link_dump - dump TIPC link data
+ * @l: tipc link to be dumped
+ * @dqueues: bitmask to decide if any link queue to be dumped?
+ *           - TIPC_DUMP_NONE: don't dump link queues
+ *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
+ *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
+ *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
+ *           - TIPC_DUMP_INPUTQ: dump link input queue
+ *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
+ *           - TIPC_DUMP_ALL: dump all the link queues above
+ * @buf: returned buffer of dump data in format
+ */
+int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
+{
+	int i = 0;
+	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
+	struct sk_buff_head *list;
+	struct sk_buff *hskb, *tskb;
+	u32 len;
+
+	if (!l) {
+		i += scnprintf(buf, sz, "link data: (null)\n");
+		return i;
+	}
+
+	i += scnprintf(buf, sz, "link data: %x", l->addr);
+	i += scnprintf(buf + i, sz - i, " %x", l->state);
+	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
+	i += scnprintf(buf + i, sz - i, " %u", l->session);
+	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
+	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
+	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
+	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
+	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
+	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
+	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
+	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
+	i += scnprintf(buf + i, sz - i, " %u", l->prev_from);
+	i += scnprintf(buf + i, sz - i, " %u", l->stale_cnt);
+	i += scnprintf(buf + i, sz - i, " %u", l->acked);
+
+	list = &l->transmq;
+	len = skb_queue_len(list);
+	hskb = skb_peek(list);
+	tskb = skb_peek_tail(list);
+	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
+		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
+		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
+
+	list = &l->deferdq;
+	len = skb_queue_len(list);
+	hskb = skb_peek(list);
+	tskb = skb_peek_tail(list);
+	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
+		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
+		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
+
+	list = &l->backlogq;
+	len = skb_queue_len(list);
+	hskb = skb_peek(list);
+	tskb = skb_peek_tail(list);
+	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
+		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
+		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
+
+	list = l->inputq;
+	len = skb_queue_len(list);
+	hskb = skb_peek(list);
+	tskb = skb_peek_tail(list);
+	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
+		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
+		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
+
+	if (dqueues & TIPC_DUMP_TRANSMQ) {
+		i += scnprintf(buf + i, sz - i, "transmq: ");
+		i += tipc_list_dump(&l->transmq, false, buf + i);
+	}
+	if (dqueues & TIPC_DUMP_BACKLOGQ) {
+		i += scnprintf(buf + i, sz - i,
+			       "backlogq: <%u %u %u %u %u>, ",
+			       l->backlog[TIPC_LOW_IMPORTANCE].len,
+			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
+			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
+			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
+			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
+		i += tipc_list_dump(&l->backlogq, false, buf + i);
+	}
+	if (dqueues & TIPC_DUMP_DEFERDQ) {
+		i += scnprintf(buf + i, sz - i, "deferdq: ");
+		i += tipc_list_dump(&l->deferdq, false, buf + i);
+	}
+	if (dqueues & TIPC_DUMP_INPUTQ) {
+		i += scnprintf(buf + i, sz - i, "inputq: ");
+		i += tipc_list_dump(l->inputq, false, buf + i);
+	}
+	if (dqueues & TIPC_DUMP_WAKEUP) {
+		i += scnprintf(buf + i, sz - i, "wakeup: ");
+		i += tipc_list_dump(&l->wakeupq, false, buf + i);
+	}
+
+	return i;
+}

net/tipc/link.h

@@ -109,6 +109,7 @@ u16 tipc_link_rcv_nxt(struct tipc_link *l);
 u16 tipc_link_acked(struct tipc_link *l);
 u32 tipc_link_id(struct tipc_link *l);
 char *tipc_link_name(struct tipc_link *l);
+char *tipc_link_name_ext(struct tipc_link *l, char *buf);
 u32 tipc_link_state(struct tipc_link *l);
 char tipc_link_plane(struct tipc_link *l);
 int tipc_link_prio(struct tipc_link *l);

net/tipc/node.c

@@ -43,6 +43,7 @@
 #include "monitor.h"
 #include "discover.h"
 #include "netlink.h"
+#include "trace.h"
 
 #define INVALID_NODE_SIG	0x10000
 #define NODE_CLEANUP_AFTER	300000
@@ -2435,3 +2436,65 @@ int tipc_nl_node_dump_monitor_peer(struct sk_buff *skb,
 
 	return skb->len;
 }
+
+u32 tipc_node_get_addr(struct tipc_node *node)
+{
+	return (node) ? node->addr : 0;
+}
+
+/**
+ * tipc_node_dump - dump TIPC node data
+ * @n: tipc node to be dumped
+ * @more: dump more?
+ *        - false: dump only tipc node data
+ *        - true: dump node link data as well
+ * @buf: returned buffer of dump data in format
+ */
+int tipc_node_dump(struct tipc_node *n, bool more, char *buf)
+{
+	int i = 0;
+	size_t sz = (more) ? NODE_LMAX : NODE_LMIN;
+
+	if (!n) {
+		i += scnprintf(buf, sz, "node data: (null)\n");
+		return i;
+	}
+
+	i += scnprintf(buf, sz, "node data: %x", n->addr);
+	i += scnprintf(buf + i, sz - i, " %x", n->state);
+	i += scnprintf(buf + i, sz - i, " %d", n->active_links[0]);
+	i += scnprintf(buf + i, sz - i, " %d", n->active_links[1]);
+	i += scnprintf(buf + i, sz - i, " %x", n->action_flags);
+	i += scnprintf(buf + i, sz - i, " %u", n->failover_sent);
+	i += scnprintf(buf + i, sz - i, " %u", n->sync_point);
+	i += scnprintf(buf + i, sz - i, " %d", n->link_cnt);
+	i += scnprintf(buf + i, sz - i, " %u", n->working_links);
+	i += scnprintf(buf + i, sz - i, " %x", n->capabilities);
+	i += scnprintf(buf + i, sz - i, " %lu\n", n->keepalive_intv);
+
+	if (!more)
+		return i;
+
+	i += scnprintf(buf + i, sz - i, "link_entry[0]:\n");
+	i += scnprintf(buf + i, sz - i, " mtu: %u\n", n->links[0].mtu);
+	i += scnprintf(buf + i, sz - i, " media: ");
+	i += tipc_media_addr_printf(buf + i, sz - i, &n->links[0].maddr);
+	i += scnprintf(buf + i, sz - i, "\n");
+	i += tipc_link_dump(n->links[0].link, TIPC_DUMP_NONE, buf + i);
+	i += scnprintf(buf + i, sz - i, " inputq: ");
+	i += tipc_list_dump(&n->links[0].inputq, false, buf + i);
+
+	i += scnprintf(buf + i, sz - i, "link_entry[1]:\n");
+	i += scnprintf(buf + i, sz - i, " mtu: %u\n", n->links[1].mtu);
+	i += scnprintf(buf + i, sz - i, " media: ");
+	i += tipc_media_addr_printf(buf + i, sz - i, &n->links[1].maddr);
+	i += scnprintf(buf + i, sz - i, "\n");
+	i += tipc_link_dump(n->links[1].link, TIPC_DUMP_NONE, buf + i);
+	i += scnprintf(buf + i, sz - i, " inputq: ");
+	i += tipc_list_dump(&n->links[1].inputq, false, buf + i);
+
+	i += scnprintf(buf + i, sz - i, "bclink:\n ");
+	i += tipc_link_dump(n->bc_entry.link, TIPC_DUMP_NONE, buf + i);
+
+	return i;
+}

net/tipc/node.h

@@ -65,6 +65,7 @@ enum {
 
 void tipc_node_stop(struct net *net);
 bool tipc_node_get_id(struct net *net, u32 addr, u8 *id);
+u32 tipc_node_get_addr(struct tipc_node *node);
 u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr);
 void tipc_node_check_dest(struct net *net, u32 onode, u8 *peer_id128,
 			  struct tipc_bearer *bearer,

net/tipc/socket.c

@@ -46,6 +46,7 @@
 #include "bcast.h"
 #include "netlink.h"
 #include "group.h"
+#include "trace.h"
 
 #define CONN_TIMEOUT_DEFAULT    8000    /* default connect timeout = 8s */
 #define CONN_PROBING_INTV	msecs_to_jiffies(3600000)  /* [ms] => 1 h */
@@ -3564,3 +3565,92 @@ int tipc_nl_publ_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
 	return skb->len;
 }
+
+u32 tipc_sock_get_portid(struct sock *sk)
+{
+	return (sk) ? (tipc_sk(sk))->portid : 0;
+}
+
+/**
+ * tipc_sk_dump - dump TIPC socket
+ * @sk: tipc sk to be dumped
+ * @dqueues: bitmask to decide if any socket queue to be dumped?
+ *           - TIPC_DUMP_NONE: don't dump socket queues
+ *           - TIPC_DUMP_SK_SNDQ: dump socket send queue
+ *           - TIPC_DUMP_SK_RCVQ: dump socket rcv queue
+ *           - TIPC_DUMP_SK_BKLGQ: dump socket backlog queue
+ *           - TIPC_DUMP_ALL: dump all the socket queues above
+ * @buf: returned buffer of dump data in format
+ */
+int tipc_sk_dump(struct sock *sk, u16 dqueues, char *buf)
+{
+	int i = 0;
+	size_t sz = (dqueues) ? SK_LMAX : SK_LMIN;
+	struct tipc_sock *tsk;
+	struct publication *p;
+	bool tsk_connected;
+
+	if (!sk) {
+		i += scnprintf(buf, sz, "sk data: (null)\n");
+		return i;
+	}
+
+	tsk = tipc_sk(sk);
+	tsk_connected = !tipc_sk_type_connectionless(sk);
+
+	i += scnprintf(buf, sz, "sk data: %u", sk->sk_type);
+	i += scnprintf(buf + i, sz - i, " %d", sk->sk_state);
+	i += scnprintf(buf + i, sz - i, " %x", tsk_own_node(tsk));
+	i += scnprintf(buf + i, sz - i, " %u", tsk->portid);
+	i += scnprintf(buf + i, sz - i, " | %u", tsk_connected);
+	if (tsk_connected) {
+		i += scnprintf(buf + i, sz - i, " %x", tsk_peer_node(tsk));
+		i += scnprintf(buf + i, sz - i, " %u", tsk_peer_port(tsk));
+		i += scnprintf(buf + i, sz - i, " %u", tsk->conn_type);
+		i += scnprintf(buf + i, sz - i, " %u", tsk->conn_instance);
+	}
+	i += scnprintf(buf + i, sz - i, " | %u", tsk->published);
+	if (tsk->published) {
+		p = list_first_entry_or_null(&tsk->publications,
+					     struct publication, binding_sock);
+		i += scnprintf(buf + i, sz - i, " %u", (p) ? p->type : 0);
+		i += scnprintf(buf + i, sz - i, " %u", (p) ? p->lower : 0);
+		i += scnprintf(buf + i, sz - i, " %u", (p) ? p->upper : 0);
+	}
+	i += scnprintf(buf + i, sz - i, " | %u", tsk->snd_win);
+	i += scnprintf(buf + i, sz - i, " %u", tsk->rcv_win);
+	i += scnprintf(buf + i, sz - i, " %u", tsk->max_pkt);
+	i += scnprintf(buf + i, sz - i, " %x", tsk->peer_caps);
+	i += scnprintf(buf + i, sz - i, " %u", tsk->cong_link_cnt);
+	i += scnprintf(buf + i, sz - i, " %u", tsk->snt_unacked);
+	i += scnprintf(buf + i, sz - i, " %u", tsk->rcv_unacked);
+	i += scnprintf(buf + i, sz - i, " %u", atomic_read(&tsk->dupl_rcvcnt));
+	i += scnprintf(buf + i, sz - i, " %u", sk->sk_shutdown);
+	i += scnprintf(buf + i, sz - i, " | %d", sk_wmem_alloc_get(sk));
+	i += scnprintf(buf + i, sz - i, " %d", sk->sk_sndbuf);
+	i += scnprintf(buf + i, sz - i, " | %d", sk_rmem_alloc_get(sk));
+	i += scnprintf(buf + i, sz - i, " %d", sk->sk_rcvbuf);
+	i += scnprintf(buf + i, sz - i, " | %d\n", sk->sk_backlog.len);
+
+	if (dqueues & TIPC_DUMP_SK_SNDQ) {
+		i += scnprintf(buf + i, sz - i, "sk_write_queue: ");
+		i += tipc_list_dump(&sk->sk_write_queue, false, buf + i);
+	}
+
+	if (dqueues & TIPC_DUMP_SK_RCVQ) {
+		i += scnprintf(buf + i, sz - i, "sk_receive_queue: ");
+		i += tipc_list_dump(&sk->sk_receive_queue, false, buf + i);
+	}
+
+	if (dqueues & TIPC_DUMP_SK_BKLGQ) {
+		i += scnprintf(buf + i, sz - i, "sk_backlog:\n  head ");
+		i += tipc_skb_dump(sk->sk_backlog.head, false, buf + i);
+		if (sk->sk_backlog.tail != sk->sk_backlog.head) {
+			i += scnprintf(buf + i, sz - i, "  tail ");
+			i += tipc_skb_dump(sk->sk_backlog.tail, false,
+					   buf + i);
+		}
+	}
+
+	return i;
+}

net/tipc/socket.h

@@ -71,4 +71,6 @@ int tipc_nl_sk_walk(struct sk_buff *skb, struct netlink_callback *cb,
 int tipc_dump_start(struct netlink_callback *cb);
 int __tipc_dump_start(struct netlink_callback *cb, struct net *net);
 int tipc_dump_done(struct netlink_callback *cb);
+u32 tipc_sock_get_portid(struct sock *sk);
+
 #endif

net/tipc/trace.c

+/*
+ * net/tipc/trace.c: TIPC tracepoints code
+ *
+ * Copyright (c) 2018, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "ASIS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
+/**
+ * tipc_skb_dump - dump TIPC skb data
+ * @skb: skb to be dumped
+ * @more: dump more?
+ *        - false: dump only tipc msg data
+ *        - true: dump kernel-related skb data and tipc cb[] array as well
+ * @buf: returned buffer of dump data in format
+ */
+int tipc_skb_dump(struct sk_buff *skb, bool more, char *buf)
+{
+	int i = 0;
+	size_t sz = (more) ? SKB_LMAX : SKB_LMIN;
+	struct tipc_msg *hdr;
+	struct tipc_skb_cb *skbcb;
+
+	if (!skb) {
+		i += scnprintf(buf, sz, "msg: (null)\n");
+		return i;
+	}
+
+	hdr = buf_msg(skb);
+	skbcb = TIPC_SKB_CB(skb);
+
+	/* tipc msg data section */
+	i += scnprintf(buf, sz, "msg: %u", msg_user(hdr));
+	i += scnprintf(buf + i, sz - i, " %u", msg_type(hdr));
+	i += scnprintf(buf + i, sz - i, " %u", msg_hdr_sz(hdr));
+	i += scnprintf(buf + i, sz - i, " %u", msg_data_sz(hdr));
+	i += scnprintf(buf + i, sz - i, " %x", msg_orignode(hdr));
+	i += scnprintf(buf + i, sz - i, " %x", msg_destnode(hdr));
+	i += scnprintf(buf + i, sz - i, " %u", msg_seqno(hdr));
+	i += scnprintf(buf + i, sz - i, " %u", msg_ack(hdr));
+	i += scnprintf(buf + i, sz - i, " %u", msg_bcast_ack(hdr));
+	switch (msg_user(hdr)) {
+	case LINK_PROTOCOL:
+		i += scnprintf(buf + i, sz - i, " %c", msg_net_plane(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_probe(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_peer_stopping(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_session(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_next_sent(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_seq_gap(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_bc_snd_nxt(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_bc_gap(hdr));
+		break;
+	case TIPC_LOW_IMPORTANCE:
+	case TIPC_MEDIUM_IMPORTANCE:
+	case TIPC_HIGH_IMPORTANCE:
+	case TIPC_CRITICAL_IMPORTANCE:
+	case CONN_MANAGER:
+	case SOCK_WAKEUP:
+		i += scnprintf(buf + i, sz - i, " | %u", msg_origport(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_destport(hdr));
+		switch (msg_type(hdr)) {
+		case TIPC_NAMED_MSG:
+			i += scnprintf(buf + i, sz - i, " %u",
+				       msg_nametype(hdr));
+			i += scnprintf(buf + i, sz - i, " %u",
+				       msg_nameinst(hdr));
+			break;
+		case TIPC_MCAST_MSG:
+			i += scnprintf(buf + i, sz - i, " %u",
+				       msg_nametype(hdr));
+			i += scnprintf(buf + i, sz - i, " %u",
+				       msg_namelower(hdr));
+			i += scnprintf(buf + i, sz - i, " %u",
+				       msg_nameupper(hdr));
+			break;
+		default:
+			break;
+		};
+		i += scnprintf(buf + i, sz - i, " | %u",
+			       msg_src_droppable(hdr));
+		i += scnprintf(buf + i, sz - i, " %u",
+			       msg_dest_droppable(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_errcode(hdr));
+		i += scnprintf(buf + i, sz - i, " %u", msg_reroute_cnt(hdr));
+		break;
+	default:
+		/* need more? */
+		break;
+	};
+
+	i += scnprintf(buf + i, sz - i, "\n");
+	if (!more)
+		return i;
+
+	/* kernel-related skb data section */
+	i += scnprintf(buf + i, sz - i, "skb: %s",
+		       (skb->dev) ? skb->dev->name : "n/a");
+	i += scnprintf(buf + i, sz - i, " %u", skb->len);
+	i += scnprintf(buf + i, sz - i, " %u", skb->data_len);
+	i += scnprintf(buf + i, sz - i, " %u", skb->hdr_len);
+	i += scnprintf(buf + i, sz - i, " %u", skb->truesize);
+	i += scnprintf(buf + i, sz - i, " %u", skb_cloned(skb));
+	i += scnprintf(buf + i, sz - i, " %p", skb->sk);
+	i += scnprintf(buf + i, sz - i, " %u", skb_shinfo(skb)->nr_frags);
+	i += scnprintf(buf + i, sz - i, " %llx",
+		       ktime_to_ms(skb_get_ktime(skb)));
+	i += scnprintf(buf + i, sz - i, " %llx\n",
+		       ktime_to_ms(skb_hwtstamps(skb)->hwtstamp));
+
+	/* tipc skb cb[] data section */
+	i += scnprintf(buf + i, sz - i, "cb[]: %u", skbcb->bytes_read);
+	i += scnprintf(buf + i, sz - i, " %u", skbcb->orig_member);
+	i += scnprintf(buf + i, sz - i, " %u",
+		       jiffies_to_msecs(skbcb->nxt_retr));
+	i += scnprintf(buf + i, sz - i, " %u", skbcb->validated);
+	i += scnprintf(buf + i, sz - i, " %u", skbcb->chain_imp);
+	i += scnprintf(buf + i, sz - i, " %u\n", skbcb->ackers);
+
+	return i;
+}
+
+/**
+ * tipc_list_dump - dump TIPC skb list/queue
+ * @list: list of skbs to be dumped
+ * @more: dump more?
+ *        - false: dump only the head & tail skbs
+ *        - true: dump the first & last 5 skbs
+ * @buf: returned buffer of dump data in format
+ */
+int tipc_list_dump(struct sk_buff_head *list, bool more, char *buf)
+{
+	int i = 0;
+	size_t sz = (more) ? LIST_LMAX : LIST_LMIN;
+	u32 count, len;
+	struct sk_buff *hskb, *tskb, *skb, *tmp;
+
+	if (!list) {
+		i += scnprintf(buf, sz, "(null)\n");
+		return i;
+	}
+
+	len = skb_queue_len(list);
+	i += scnprintf(buf, sz, "len = %d\n", len);
+
+	if (!len)
+		return i;
+
+	if (!more) {
+		hskb = skb_peek(list);
+		i += scnprintf(buf + i, sz - i, "  head ");
+		i += tipc_skb_dump(hskb, false, buf + i);
+		if (len > 1) {
+			tskb = skb_peek_tail(list);
+			i += scnprintf(buf + i, sz - i, "  tail ");
+			i += tipc_skb_dump(tskb, false, buf + i);
+		}
+	} else {
+		count = 0;
+		skb_queue_walk_safe(list, skb, tmp) {
+			count++;
+			if (count == 6)
+				i += scnprintf(buf + i, sz - i, "  .\n  .\n");
+			if (count > 5 && count <= len - 5)
+				continue;
+			i += scnprintf(buf + i, sz - i, "  #%d ", count);
+			i += tipc_skb_dump(skb, false, buf + i);
+		}
+	}
+	return i;
+}

net/tipc/trace.h

+/*
+ * net/tipc/trace.h: TIPC tracepoints
+ *
+ * Copyright (c) 2018, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "ASIS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM tipc
+
+#if !defined(_TIPC_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TIPC_TRACE_H
+
+#include <linux/tracepoint.h>
+#include "core.h"
+#include "link.h"
+#include "socket.h"
+#include "node.h"
+
+#define SKB_LMIN	(100)
+#define SKB_LMAX	(SKB_LMIN * 2)
+#define LIST_LMIN	(SKB_LMIN * 3)
+#define LIST_LMAX	(SKB_LMIN * 11)
+#define SK_LMIN		(SKB_LMIN * 2)
+#define SK_LMAX		(SKB_LMIN * 11)
+#define LINK_LMIN	(SKB_LMIN)
+#define LINK_LMAX	(SKB_LMIN * 16)
+#define NODE_LMIN	(SKB_LMIN)
+#define NODE_LMAX	(SKB_LMIN * 11)
+
+#ifndef __TIPC_TRACE_ENUM
+#define __TIPC_TRACE_ENUM
+enum {
+	TIPC_DUMP_NONE		= 0,
+
+	TIPC_DUMP_TRANSMQ	= 1,
+	TIPC_DUMP_BACKLOGQ	= (1 << 1),
+	TIPC_DUMP_DEFERDQ	= (1 << 2),
+	TIPC_DUMP_INPUTQ	= (1 << 3),
+	TIPC_DUMP_WAKEUP        = (1 << 4),
+
+	TIPC_DUMP_SK_SNDQ	= (1 << 8),
+	TIPC_DUMP_SK_RCVQ	= (1 << 9),
+	TIPC_DUMP_SK_BKLGQ	= (1 << 10),
+	TIPC_DUMP_ALL		= 0xffffu
+};
+#endif
+
+int tipc_skb_dump(struct sk_buff *skb, bool more, char *buf);
+int tipc_list_dump(struct sk_buff_head *list, bool more, char *buf);
+int tipc_sk_dump(struct sock *sk, u16 dqueues, char *buf);
+int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf);
+int tipc_node_dump(struct tipc_node *n, bool more, char *buf);
+
+DECLARE_EVENT_CLASS(tipc_skb_class,
+
+	TP_PROTO(struct sk_buff *skb, bool more, const char *header),
+
+	TP_ARGS(skb, more, header),
+
+	TP_STRUCT__entry(
+		__string(header, header)
+		__dynamic_array(char, buf, (more) ? SKB_LMAX : SKB_LMIN)
+	),
+
+	TP_fast_assign(
+		__assign_str(header, header);
+		tipc_skb_dump(skb, more, __get_str(buf));
+	),
+
+	TP_printk("%s\n%s", __get_str(header), __get_str(buf))
+)
+
+#define DEFINE_SKB_EVENT(name) \
+DEFINE_EVENT(tipc_skb_class, name, \
+	TP_PROTO(struct sk_buff *skb, bool more, const char *header), \
+	TP_ARGS(skb, more, header))
+DEFINE_SKB_EVENT(tipc_skb_dump);
+
+DECLARE_EVENT_CLASS(tipc_list_class,
+
+	TP_PROTO(struct sk_buff_head *list, bool more, const char *header),
+
+	TP_ARGS(list, more, header),
+
+	TP_STRUCT__entry(
+		__string(header, header)
+		__dynamic_array(char, buf, (more) ? LIST_LMAX : LIST_LMIN)
+	),
+
+	TP_fast_assign(
+		__assign_str(header, header);
+		tipc_list_dump(list, more, __get_str(buf));
+	),
+
+	TP_printk("%s\n%s", __get_str(header), __get_str(buf))
+);
+
+#define DEFINE_LIST_EVENT(name) \
+DEFINE_EVENT(tipc_list_class, name, \
+	TP_PROTO(struct sk_buff_head *list, bool more, const char *header), \
+	TP_ARGS(list, more, header))
+DEFINE_LIST_EVENT(tipc_list_dump);
+
+DECLARE_EVENT_CLASS(tipc_sk_class,
+
+	TP_PROTO(struct sock *sk, struct sk_buff *skb, u16 dqueues,
+		 const char *header),
+
+	TP_ARGS(sk, skb, dqueues, header),
+
+	TP_STRUCT__entry(
+		__string(header, header)
+		__field(u32, portid)
+		__dynamic_array(char, buf, (dqueues) ? SK_LMAX : SK_LMIN)
+		__dynamic_array(char, skb_buf, (skb) ? SKB_LMIN : 1)
+	),
+
+	TP_fast_assign(
+		__assign_str(header, header);
+		__entry->portid = tipc_sock_get_portid(sk);
+		tipc_sk_dump(sk, dqueues, __get_str(buf));
+		if (skb)
+			tipc_skb_dump(skb, false, __get_str(skb_buf));
+		else
+			*(__get_str(skb_buf)) = '\0';
+	),
+
+	TP_printk("<%u> %s\n%s%s", __entry->portid, __get_str(header),
+		  __get_str(skb_buf), __get_str(buf))
+);
+
+#define DEFINE_SK_EVENT(name) \
+DEFINE_EVENT(tipc_sk_class, name, \
+	TP_PROTO(struct sock *sk, struct sk_buff *skb, u16 dqueues, \
+		 const char *header), \
+	TP_ARGS(sk, skb, dqueues, header))
+DEFINE_SK_EVENT(tipc_sk_dump);
+
+DECLARE_EVENT_CLASS(tipc_link_class,
+
+	TP_PROTO(struct tipc_link *l, u16 dqueues, const char *header),
+
+	TP_ARGS(l, dqueues, header),
+
+	TP_STRUCT__entry(
+		__string(header, header)
+		__array(char, name, TIPC_MAX_LINK_NAME)
+		__dynamic_array(char, buf, (dqueues) ? LINK_LMAX : LINK_LMIN)
+	),
+
+	TP_fast_assign(
+		__assign_str(header, header);
+		tipc_link_name_ext(l, __entry->name);
+		tipc_link_dump(l, dqueues, __get_str(buf));
+	),
+
+	TP_printk("<%s> %s\n%s", __entry->name, __get_str(header),
+		  __get_str(buf))
+);
+
+#define DEFINE_LINK_EVENT(name) \
+DEFINE_EVENT(tipc_link_class, name, \
+	TP_PROTO(struct tipc_link *l, u16 dqueues, const char *header), \
+	TP_ARGS(l, dqueues, header))
+DEFINE_LINK_EVENT(tipc_link_dump);
+
+DECLARE_EVENT_CLASS(tipc_node_class,
+
+	TP_PROTO(struct tipc_node *n, bool more, const char *header),
+
+	TP_ARGS(n, more, header),
+
+	TP_STRUCT__entry(
+		__string(header, header)
+		__field(u32, addr)
+		__dynamic_array(char, buf, (more) ? NODE_LMAX : NODE_LMIN)
+	),
+
+	TP_fast_assign(
+		__assign_str(header, header);
+		__entry->addr = tipc_node_get_addr(n);
+		tipc_node_dump(n, more, __get_str(buf));
+	),
+
+	TP_printk("<%x> %s\n%s", __entry->addr, __get_str(header),
+		  __get_str(buf))
+);
+
+#define DEFINE_NODE_EVENT(name) \
+DEFINE_EVENT(tipc_node_class, name, \
+	TP_PROTO(struct tipc_node *n, bool more, const char *header), \
+	TP_ARGS(n, more, header))
+DEFINE_NODE_EVENT(tipc_node_dump);
+
+#endif /* _TIPC_TRACE_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+#include <trace/define_trace.h>