From b63c5478e9cb1d1504eb02d9dac827ad24612b32 Mon Sep 17 00:00:00 2001
From: Justin Iurman <justin.iurman@uliege.be>
Date: Thu, 30 Dec 2021 18:10:04 +0100
Subject: [PATCH] ipv6: ioam: Support for Queue depth data field
v3:
- Report 'backlog' (bytes) instead of 'qlen' (number of packets)
v2:
- Fix sparse warning (use rcu_dereference)
This patch adds support for the queue depth in IOAM trace data fields.
The draft [1] says the following:
The "queue depth" field is a 4-octet unsigned integer field. This
field indicates the current length of the egress interface queue of
the interface from where the packet is forwarded out. The queue
depth is expressed as the current amount of memory buffers used by
the queue (a packet could consume one or more memory buffers,
depending on its size).
An existing function (i.e., qdisc_qstats_qlen_backlog) is used to
retrieve the current queue length without reinventing the wheel.
Note: it was tested and qlen is increasing when an artificial delay is
added on the egress with tc.
[1] https://datatracker.ietf.org/doc/html/draft-ietf-ippm-ioam-data#section-5.4.2.7
Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv6/ioam6.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/ioam6.c b/net/ipv6/ioam6.c
index 122a3d47424c7..e159eb4328a87 100644
--- a/net/ipv6/ioam6.c
+++ b/net/ipv6/ioam6.c
@@ -13,10 +13,12 @@
#include <linux/ioam6.h>
#include <linux/ioam6_genl.h>
#include <linux/rhashtable.h>
+#include <linux/netdevice.h>
#include <net/addrconf.h>
#include <net/genetlink.h>
#include <net/ioam6.h>
+#include <net/sch_generic.h>
static void ioam6_ns_release(struct ioam6_namespace *ns)
{
@@ -717,7 +719,19 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb,
/* queue depth */
if (trace->type.bit6) {
- *(__be32 *)data = cpu_to_be32(IOAM6_U32_UNAVAILABLE);
+ struct netdev_queue *queue;
+ struct Qdisc *qdisc;
+ __u32 qlen, backlog;
+
+ if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+ *(__be32 *)data = cpu_to_be32(IOAM6_U32_UNAVAILABLE);
+ } else {
+ queue = skb_get_tx_queue(skb_dst(skb)->dev, skb);
+ qdisc = rcu_dereference(queue->qdisc);
+ qdisc_qstats_qlen_backlog(qdisc, &qlen, &backlog);
+
+ *(__be32 *)data = cpu_to_be32(backlog);
+ }
data += sizeof(__be32);
}
--
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