Merge branch 'add-support-for-so_priority-cmsg'

Anna Emese Nyiri says:

====================
Add support for SO_PRIORITY cmsg

Introduce a new helper function, `sk_set_prio_allowed`,
to centralize the logic for validating priority settings.
Add support for the `SO_PRIORITY` control message,
enabling user-space applications to set socket priority
via control messages (cmsg).
====================

Link: https://patch.msgid.link/20241213084457.45120-1-annaemesenyiri@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

arch/alpha/include/uapi/asm/socket.h

@@ -148,6 +148,8 @@
 
 #define SCM_TS_OPT_ID		81
 
+#define SO_RCVPRIORITY		82
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64

arch/mips/include/uapi/asm/socket.h

@@ -159,6 +159,8 @@
 
 #define SCM_TS_OPT_ID		81
 
+#define SO_RCVPRIORITY		82
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64

arch/parisc/include/uapi/asm/socket.h

@@ -140,6 +140,8 @@
 
 #define SCM_TS_OPT_ID		0x404C
 
+#define SO_RCVPRIORITY		0x404D
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64

arch/sparc/include/uapi/asm/socket.h

@@ -141,6 +141,8 @@
 
 #define SCM_TS_OPT_ID            0x005a
 
+#define SO_RCVPRIORITY           0x005b
+
 #if !defined(__KERNEL__)
 
 

include/net/inet_sock.h

@@ -172,7 +172,7 @@ struct inet_cork {
 	u8			tx_flags;
 	__u8			ttl;
 	__s16			tos;
-	char			priority;
+	u32			priority;
 	__u16			gso_size;
 	u32			ts_opt_id;
 	u64			transmit_time;

include/net/ip.h

@@ -81,7 +81,6 @@ struct ipcm_cookie {
 	__u8			protocol;
 	__u8			ttl;
 	__s16			tos;
-	char			priority;
 	__u16			gso_size;
 };
 
@@ -96,6 +95,7 @@ static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
 	ipcm_init(ipcm);
 
 	ipcm->sockc.mark = READ_ONCE(inet->sk.sk_mark);
+	ipcm->sockc.priority = READ_ONCE(inet->sk.sk_priority);
 	ipcm->sockc.tsflags = READ_ONCE(inet->sk.sk_tsflags);
 	ipcm->oif = READ_ONCE(inet->sk.sk_bound_dev_if);
 	ipcm->addr = inet->inet_saddr;

include/net/sock.h

@@ -953,6 +953,7 @@ enum sock_flags {
 	SOCK_XDP, /* XDP is attached */
 	SOCK_TSTAMP_NEW, /* Indicates 64 bit timestamps always */
 	SOCK_RCVMARK, /* Receive SO_MARK  ancillary data with packet */
+	SOCK_RCVPRIORITY, /* Receive SO_PRIORITY ancillary data with packet */
 };
 
 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
@@ -1814,13 +1815,15 @@ struct sockcm_cookie {
 	u32 mark;
 	u32 tsflags;
 	u32 ts_opt_id;
+	u32 priority;
 };
 
 static inline void sockcm_init(struct sockcm_cookie *sockc,
 			       const struct sock *sk)
 {
 	*sockc = (struct sockcm_cookie) {
-		.tsflags = READ_ONCE(sk->sk_tsflags)
+		.tsflags = READ_ONCE(sk->sk_tsflags),
+		.priority = READ_ONCE(sk->sk_priority),
 	};
 }
 
@@ -2658,7 +2661,8 @@ static inline void sock_recv_cmsgs(struct msghdr *msg, struct sock *sk,
 {
 #define FLAGS_RECV_CMSGS ((1UL << SOCK_RXQ_OVFL)			| \
 			   (1UL << SOCK_RCVTSTAMP)			| \
-			   (1UL << SOCK_RCVMARK))
+			   (1UL << SOCK_RCVMARK)			|\
+			   (1UL << SOCK_RCVPRIORITY))
 #define TSFLAGS_ANY	  (SOF_TIMESTAMPING_SOFTWARE			| \
 			   SOF_TIMESTAMPING_RAW_HARDWARE)
 

include/uapi/asm-generic/socket.h

@@ -143,6 +143,8 @@
 
 #define SCM_TS_OPT_ID		81
 
+#define SO_RCVPRIORITY		82
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))

net/can/raw.c

@@ -962,7 +962,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	}
 
 	skb->dev = dev;
-	skb->priority = READ_ONCE(sk->sk_priority);
+	skb->priority = sockc.priority;
 	skb->mark = READ_ONCE(sk->sk_mark);
 	skb->tstamp = sockc.transmit_time;
 

net/core/sock.c

@@ -454,6 +454,13 @@ static int sock_set_timeout(long *timeo_p, sockptr_t optval, int optlen,
 	return 0;
 }
 
+static bool sk_set_prio_allowed(const struct sock *sk, int val)
+{
+	return ((val >= TC_PRIO_BESTEFFORT && val <= TC_PRIO_INTERACTIVE) ||
+		sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) ||
+		sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN));
+}
+
 static bool sock_needs_netstamp(const struct sock *sk)
 {
 	switch (sk->sk_family) {
@@ -1193,9 +1200,7 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
 	/* handle options which do not require locking the socket. */
 	switch (optname) {
 	case SO_PRIORITY:
-		if ((val >= 0 && val <= 6) ||
-		    sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) ||
-		    sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
+		if (sk_set_prio_allowed(sk, val)) {
 			sock_set_priority(sk, val);
 			return 0;
 		}
@@ -1514,6 +1519,10 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
 		sock_valbool_flag(sk, SOCK_RCVMARK, valbool);
 		break;
 
+	case SO_RCVPRIORITY:
+		sock_valbool_flag(sk, SOCK_RCVPRIORITY, valbool);
+		break;
+
 	case SO_RXQ_OVFL:
 		sock_valbool_flag(sk, SOCK_RXQ_OVFL, valbool);
 		break;
@@ -1942,6 +1951,10 @@ int sk_getsockopt(struct sock *sk, int level, int optname,
 		v.val = sock_flag(sk, SOCK_RCVMARK);
 		break;
 
+	case SO_RCVPRIORITY:
+		v.val = sock_flag(sk, SOCK_RCVPRIORITY);
+		break;
+
 	case SO_RXQ_OVFL:
 		v.val = sock_flag(sk, SOCK_RXQ_OVFL);
 		break;
@@ -2942,6 +2955,13 @@ int __sock_cmsg_send(struct sock *sk, struct cmsghdr *cmsg,
 	case SCM_RIGHTS:
 	case SCM_CREDENTIALS:
 		break;
+	case SO_PRIORITY:
+		if (cmsg->cmsg_len != CMSG_LEN(sizeof(u32)))
+			return -EINVAL;
+		if (!sk_set_prio_allowed(sk, *(u32 *)CMSG_DATA(cmsg)))
+			return -EPERM;
+		sockc->priority = *(u32 *)CMSG_DATA(cmsg);
+		break;
 	default:
 		return -EINVAL;
 	}

net/ipv4/ip_output.c

@@ -1333,7 +1333,7 @@ static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
 	cork->ttl = ipc->ttl;
 	cork->tos = ipc->tos;
 	cork->mark = ipc->sockc.mark;
-	cork->priority = ipc->priority;
+	cork->priority = ipc->sockc.priority;
 	cork->transmit_time = ipc->sockc.transmit_time;
 	cork->tx_flags = 0;
 	sock_tx_timestamp(sk, &ipc->sockc, &cork->tx_flags);
@@ -1470,7 +1470,7 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
 		ip_options_build(skb, opt, cork->addr, rt);
 	}
 
-	skb->priority = (cork->tos != -1) ? cork->priority: READ_ONCE(sk->sk_priority);
+	skb->priority = cork->priority;
 	skb->mark = cork->mark;
 	if (sk_is_tcp(sk))
 		skb_set_delivery_time(skb, cork->transmit_time, SKB_CLOCK_MONOTONIC);

net/ipv4/ip_sockglue.c

@@ -315,7 +315,7 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg, struct ipcm_cookie *ipc,
 			if (val < 0 || val > 255)
 				return -EINVAL;
 			ipc->tos = val;
-			ipc->priority = rt_tos2priority(ipc->tos);
+			ipc->sockc.priority = rt_tos2priority(ipc->tos);
 			break;
 		case IP_PROTOCOL:
 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))

net/ipv4/raw.c

@@ -358,7 +358,7 @@ static int raw_send_hdrinc(struct sock *sk, struct flowi4 *fl4,
 	skb_reserve(skb, hlen);
 
 	skb->protocol = htons(ETH_P_IP);
-	skb->priority = READ_ONCE(sk->sk_priority);
+	skb->priority = sockc->priority;
 	skb->mark = sockc->mark;
 	skb_set_delivery_type_by_clockid(skb, sockc->transmit_time, sk->sk_clockid);
 	skb_dst_set(skb, &rt->dst);

net/ipv6/ip6_output.c

@@ -1401,6 +1401,7 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
 	cork->base.gso_size = ipc6->gso_size;
 	cork->base.tx_flags = 0;
 	cork->base.mark = ipc6->sockc.mark;
+	cork->base.priority = ipc6->sockc.priority;
 	sock_tx_timestamp(sk, &ipc6->sockc, &cork->base.tx_flags);
 	if (ipc6->sockc.tsflags & SOCKCM_FLAG_TS_OPT_ID) {
 		cork->base.flags |= IPCORK_TS_OPT_ID;
@@ -1942,7 +1943,7 @@ struct sk_buff *__ip6_make_skb(struct sock *sk,
 	hdr->saddr = fl6->saddr;
 	hdr->daddr = *final_dst;
 
-	skb->priority = READ_ONCE(sk->sk_priority);
+	skb->priority = cork->base.priority;
 	skb->mark = cork->base.mark;
 	if (sk_is_tcp(sk))
 		skb_set_delivery_time(skb, cork->base.transmit_time, SKB_CLOCK_MONOTONIC);

net/ipv6/ping.c

@@ -119,6 +119,7 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		return -EINVAL;
 
 	ipcm6_init_sk(&ipc6, sk);
+	ipc6.sockc.priority = READ_ONCE(sk->sk_priority);
 	ipc6.sockc.tsflags = READ_ONCE(sk->sk_tsflags);
 	ipc6.sockc.mark = READ_ONCE(sk->sk_mark);
 

net/ipv6/raw.c

@@ -619,7 +619,7 @@ static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length,
 	skb_reserve(skb, hlen);
 
 	skb->protocol = htons(ETH_P_IPV6);
-	skb->priority = READ_ONCE(sk->sk_priority);
+	skb->priority = sockc->priority;
 	skb->mark = sockc->mark;
 	skb_set_delivery_type_by_clockid(skb, sockc->transmit_time, sk->sk_clockid);
 
@@ -780,6 +780,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipcm6_init(&ipc6);
 	ipc6.sockc.tsflags = READ_ONCE(sk->sk_tsflags);
 	ipc6.sockc.mark = fl6.flowi6_mark;
+	ipc6.sockc.priority = READ_ONCE(sk->sk_priority);
 
 	if (sin6) {
 		if (addr_len < SIN6_LEN_RFC2133)

net/ipv6/udp.c

@@ -1448,6 +1448,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc6.gso_size = READ_ONCE(up->gso_size);
 	ipc6.sockc.tsflags = READ_ONCE(sk->sk_tsflags);
 	ipc6.sockc.mark = READ_ONCE(sk->sk_mark);
+	ipc6.sockc.priority = READ_ONCE(sk->sk_priority);
 
 	/* destination address check */
 	if (sin6) {

net/packet/af_packet.c

@@ -3126,7 +3126,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
 
 	skb->protocol = proto;
 	skb->dev = dev;
-	skb->priority = READ_ONCE(sk->sk_priority);
+	skb->priority = sockc.priority;
 	skb->mark = sockc.mark;
 	skb_set_delivery_type_by_clockid(skb, sockc.transmit_time, sk->sk_clockid);
 

net/socket.c

@@ -1008,12 +1008,23 @@ static void sock_recv_mark(struct msghdr *msg, struct sock *sk,
 	}
 }
 
+static void sock_recv_priority(struct msghdr *msg, struct sock *sk,
+			       struct sk_buff *skb)
+{
+	if (sock_flag(sk, SOCK_RCVPRIORITY) && skb) {
+		__u32 priority = skb->priority;
+
+		put_cmsg(msg, SOL_SOCKET, SO_PRIORITY, sizeof(__u32), &priority);
+	}
+}
+
 void __sock_recv_cmsgs(struct msghdr *msg, struct sock *sk,
 		       struct sk_buff *skb)
 {
 	sock_recv_timestamp(msg, sk, skb);
 	sock_recv_drops(msg, sk, skb);
 	sock_recv_mark(msg, sk, skb);
+	sock_recv_priority(msg, sk, skb);
 }
 EXPORT_SYMBOL_GPL(__sock_recv_cmsgs);
 

tools/include/uapi/asm-generic/socket.h

@@ -126,6 +126,8 @@
 
 #define SCM_TS_OPT_ID		78
 
+#define SO_RCVPRIORITY		79
+
 #if !defined(__KERNEL__)
 
 #if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))

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