selftests: net: test SO_PRIORITY ancillary data with cmsg_sender

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

cmsg_so_priority.sh script added to validate SO_PRIORITY behavior
by creating VLAN device with egress QoS mapping and testing packet
priorities using flower filters. Verify that packets with different
priorities are correctly matched and counted by filters for multiple
protocols and IP versions.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Suggested-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Anna Emese Nyiri <annaemesenyiri@gmail.com>
Link: https://patch.msgid.link/20241213084457.45120-4-annaemesenyiri@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/Makefile

@@ -32,6 +32,7 @@ TEST_PROGS += ioam6.sh
 TEST_PROGS += gro.sh
 TEST_PROGS += gre_gso.sh
 TEST_PROGS += cmsg_so_mark.sh
+TEST_PROGS += cmsg_so_priority.sh
 TEST_PROGS += cmsg_time.sh cmsg_ipv6.sh
 TEST_PROGS += netns-name.sh
 TEST_PROGS += nl_netdev.py

tools/testing/selftests/net/cmsg_sender.c

@@ -59,6 +59,7 @@ struct options {
 		unsigned int proto;
 	} sock;
 	struct option_cmsg_u32 mark;
+	struct option_cmsg_u32 priority;
 	struct {
 		bool ena;
 		unsigned int delay;
@@ -97,6 +98,8 @@ static void __attribute__((noreturn)) cs_usage(const char *bin)
 	       "\n"
 	       "\t\t-m val  Set SO_MARK with given value\n"
 	       "\t\t-M val  Set SO_MARK via setsockopt\n"
+	       "\t\t-P val  Set SO_PRIORITY via setsockopt\n"
+	       "\t\t-Q val  Set SO_PRIORITY via cmsg\n"
 	       "\t\t-d val  Set SO_TXTIME with given delay (usec)\n"
 	       "\t\t-t      Enable time stamp reporting\n"
 	       "\t\t-f val  Set don't fragment via cmsg\n"
@@ -115,7 +118,7 @@ static void cs_parse_args(int argc, char *argv[])
 {
 	int o;
 
-	while ((o = getopt(argc, argv, "46sS:p:P:m:M:n:d:tf:F:c:C:l:L:H:")) != -1) {
+	while ((o = getopt(argc, argv, "46sS:p:P:m:M:n:d:tf:F:c:C:l:L:H:Q:")) != -1) {
 		switch (o) {
 		case 's':
 			opt.silent_send = true;
@@ -148,6 +151,10 @@ static void cs_parse_args(int argc, char *argv[])
 			opt.mark.ena = true;
 			opt.mark.val = atoi(optarg);
 			break;
+		case 'Q':
+			opt.priority.ena = true;
+			opt.priority.val = atoi(optarg);
+			break;
 		case 'M':
 			opt.sockopt.mark = atoi(optarg);
 			break;
@@ -252,6 +259,8 @@ cs_write_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
 
 	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
 			  SOL_SOCKET, SO_MARK, &opt.mark);
+	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
+			  SOL_SOCKET, SO_PRIORITY, &opt.priority);
 	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
 			  SOL_IPV6, IPV6_DONTFRAG, &opt.v6.dontfrag);
 	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,

tools/testing/selftests/net/cmsg_so_priority.sh

@@ -0,0 +1,151 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source lib.sh
+
+readonly KSFT_SKIP=4
+
+IP4=192.0.2.1/24
+TGT4=192.0.2.2
+TGT4_RAW=192.0.2.3
+IP6=2001:db8::1/64
+TGT6=2001:db8::2
+TGT6_RAW=2001:db8::3
+PORT=1234
+TOTAL_TESTS=0
+FAILED_TESTS=0
+
+if ! command -v jq &> /dev/null; then
+    echo "SKIP cmsg_so_priroity.sh test: jq is not installed." >&2
+    exit "$KSFT_SKIP"
+fi
+
+check_result() {
+    ((TOTAL_TESTS++))
+    if [ "$1" -ne 0 ]; then
+        ((FAILED_TESTS++))
+    fi
+}
+
+cleanup()
+{
+    cleanup_ns $NS
+}
+
+trap cleanup EXIT
+
+setup_ns NS
+
+create_filter() {
+    local handle=$1
+    local vlan_prio=$2
+    local ip_type=$3
+    local proto=$4
+    local dst_ip=$5
+    local ip_proto
+
+    if [[ "$proto" == "u" ]]; then
+        ip_proto="udp"
+    elif [[ "$ip_type" == "ipv4" && "$proto" == "i" ]]; then
+        ip_proto="icmp"
+    elif [[ "$ip_type" == "ipv6" && "$proto" == "i" ]]; then
+        ip_proto="icmpv6"
+    fi
+
+    tc -n $NS filter add dev dummy1 \
+        egress pref 1 handle "$handle" proto 802.1q \
+        flower vlan_prio "$vlan_prio" vlan_ethtype "$ip_type" \
+        dst_ip "$dst_ip" ${ip_proto:+ip_proto $ip_proto} \
+        action pass
+}
+
+ip -n $NS link set dev lo up
+ip -n $NS link add name dummy1 up type dummy
+
+ip -n $NS link add link dummy1 name dummy1.10 up type vlan id 10 \
+    egress-qos-map 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7
+
+ip -n $NS address add $IP4 dev dummy1.10
+ip -n $NS address add $IP6 dev dummy1.10 nodad
+
+ip netns exec $NS sysctl -wq net.ipv4.ping_group_range='0 2147483647'
+
+ip -n $NS neigh add $TGT4 lladdr 00:11:22:33:44:55 nud permanent \
+    dev dummy1.10
+ip -n $NS neigh add $TGT6 lladdr 00:11:22:33:44:55 nud permanent \
+    dev dummy1.10
+ip -n $NS neigh add $TGT4_RAW lladdr 00:11:22:33:44:66 nud permanent \
+    dev dummy1.10
+ip -n $NS neigh add $TGT6_RAW lladdr 00:11:22:33:44:66 nud permanent \
+    dev dummy1.10
+
+tc -n $NS qdisc add dev dummy1 clsact
+
+FILTER_COUNTER=10
+
+for i in 4 6; do
+    for proto in u i r; do
+        echo "Test IPV$i, prot: $proto"
+        for priority in {0..7}; do
+            if [[ $i == 4 && $proto == "r" ]]; then
+                TGT=$TGT4_RAW
+            elif [[ $i == 6 && $proto == "r" ]]; then
+                TGT=$TGT6_RAW
+            elif [ $i == 4 ]; then
+                TGT=$TGT4
+            else
+                TGT=$TGT6
+            fi
+
+            handle="${FILTER_COUNTER}${priority}"
+
+            create_filter $handle $priority ipv$i $proto $TGT
+
+            pkts=$(tc -n $NS -j -s filter show dev dummy1 egress \
+                | jq ".[] | select(.options.handle == ${handle}) | \
+                .options.actions[0].stats.packets")
+
+            if [[ $pkts == 0 ]]; then
+                check_result 0
+            else
+                echo "prio $priority: expected 0, got $pkts"
+                check_result 1
+            fi
+
+            ip netns exec $NS ./cmsg_sender -$i -Q $priority \
+	            -p $proto $TGT $PORT
+
+            pkts=$(tc -n $NS -j -s filter show dev dummy1 egress \
+                | jq ".[] | select(.options.handle == ${handle}) | \
+                .options.actions[0].stats.packets")
+            if [[ $pkts == 1 ]]; then
+                check_result 0
+            else
+                echo "prio $priority -Q: expected 1, got $pkts"
+                check_result 1
+            fi
+
+            ip netns exec $NS ./cmsg_sender -$i -P $priority \
+	            -p $proto $TGT $PORT
+
+            pkts=$(tc -n $NS -j -s filter show dev dummy1 egress \
+                | jq ".[] | select(.options.handle == ${handle}) | \
+                .options.actions[0].stats.packets")
+            if [[ $pkts == 2 ]]; then
+                check_result 0
+            else
+                echo "prio $priority -P: expected 2, got $pkts"
+                check_result 1
+            fi
+        done
+        FILTER_COUNTER=$((FILTER_COUNTER + 10))
+    done
+done
+
+if [ $FAILED_TESTS -ne 0 ]; then
+    echo "FAIL - $FAILED_TESTS/$TOTAL_TESTS tests failed"
+    exit 1
+else
+    echo "OK - All $TOTAL_TESTS tests passed"
+    exit 0
+fi