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>

1 files changed, 200 insertions, 0 deletions

diff --git a/net/tipc/trace.c b/net/tipc/trace.c
new file mode 100644
index 000000000000..846196f0e810
--- /dev/null
+++ b/net/tipc/trace.c
@@ -0,0 +1,200 @@
+/*
+ * 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;
+}