netdev - [PATCH net-next v2] ipv6: ioam: Support for Queue depth data field

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211224135000.9291-1-justin.iurman@uliege.be>
Date:   Fri, 24 Dec 2021 14:50:00 +0100
From:   Justin Iurman <justin.iurman@...ege.be>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, dsahern@...nel.org,
        yoshfuji@...ux-ipv6.org, justin.iurman@...ege.be
Subject: [PATCH net-next v2] ipv6: ioam: Support for Queue depth data field

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@...ege.be>
---
 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 122a3d47424c..969a5adbaf5c 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(qlen);
+		}
 		data += sizeof(__be32);
 	}
 
-- 
2.25.1