Ferenc Fejes wrote:

On Fri, 2024-11-08 at 09:46 -0500, Willem de Bruijn wrote:

quoted

Willem de Bruijn wrote:

quoted

Anna Emese Nyiri wrote:

quoted

Extend cmsg_sender.c with a new option '-Q' to send SO_PRIORITY
ancillary data.

Add the `cmsg_so_priority.sh` script, which sets up two network  
namespaces (red and green) and uses the `cmsg_sender.c` program
to  
send messages between them. The script sets packet priorities
both  
via `setsockopt` and control messages (cmsg) and verifies
whether  
packets are routed to the same queue based on priority settings.

qdisc. queue is a more generic term, generally referring to hw
queues.
 

quoted

Suggested-by: Ido Schimmel <redacted>
Signed-off-by: Anna Emese Nyiri <redacted>
---
 tools/testing/selftests/net/cmsg_sender.c     |  11 +-
 .../testing/selftests/net/cmsg_so_priority.sh | 115
++++++++++++++++++
 2 files changed, 125 insertions(+), 1 deletion(-)
 create mode 100755
tools/testing/selftests/net/cmsg_so_priority.sh

quoted

diff --git a/tools/testing/selftests/net/cmsg_so_priority.sh

b/tools/testing/selftests/net/cmsg_so_priority.sh
new file mode 100755
index 000000000000..706d29b251e9

--- /dev/null
+++ b/tools/testing/selftests/net/cmsg_so_priority.sh

@@ -0,0 +1,115 @@
+#!/bin/bash

SPDX header

quoted

+
+source lib.sh
+
+IP4=192.168.0.2/16
+TGT4=192.168.0.3/16
+TGT4_NO_MASK=192.168.0.3
+IP6=2001:db8::2/64
+TGT6=2001:db8::3/64
+TGT6_NO_MASK=2001:db8::3
+IP4BR=192.168.0.1/16
+IP6BR=2001:db8::1/64
+PORT=8080
+DELAY=400000
+QUEUE_NUM=4
+
+
+cleanup() {
+    ip netns del red 2>/dev/null
+    ip netns del green 2>/dev/null
+    ip link del br0 2>/dev/null
+    ip link del vethcab0 2>/dev/null
+    ip link del vethcab1 2>/dev/null
+}
+
+trap cleanup EXIT
+
+priority_values=($(seq 0 $((QUEUE_NUM - 1))))
+
+queue_config=""
+for ((i=0; i<$QUEUE_NUM; i++)); do
+    queue_config+=" 1@$i"
+done
+
+map_config=$(seq 0 $((QUEUE_NUM - 1)) | tr '\n' ' ')
+
+ip netns add red
+ip netns add green
+ip link add br0 type bridge
+ip link set br0 up

Is this bridge needed? Can this just use a veth pair as is.

More importantly, it would be great if we can deduplicate this kind
of
setup boilerplate across similar tests as much as possible.

As a matter of fact, similar to cmsg_so_mark, this test can probably
use a dummy netdevice, no need for a second namespace and dev.

cmsg_so_mark.sh is probably small enough that it is fine to copy that
and create a duplicate. As trying to extend it to cover both tests
will probably double it in size and will just be harder to follow.

I'm afraid we don't have "ip rule" match argument for skb->priority
like we have for skb->mark (ip rule fwmark). AFAIU cmsg_so_mark.sh uses
rule matches to confirm if skb->mark is correct or not.

Using nftables meta priority would work with a dummy device:
add table so_prio
add chain so_prio so_prio_chain { type filter hook output priority 0; }
add rule so_prio so_prio_chain meta priority $SOPRIOVALUE counter

Is there anything simpler? I am afraid we cannot use nftables in
selftests, or can we? Thanks!

I'd use traffic shaper (tc). There are a variety of qdiscs/schedulers
and classifiers that act on skb->priority.