ping: Stop using RTO_ONLINK.

Define a new helper to figure out the correct route scope to use on TX,
depending on socket configuration, ancillary data and send flags.

Use this new helper to properly initialise the scope in
flowi4_init_output(), instead of overriding tos with the RTO_ONLINK
flag.

The objective is to eventually remove RTO_ONLINK, which will allow
converting .flowi4_tos to dscp_t.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -240,6 +240,19 @@ static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 }
 
+/* Get the route scope that should be used when sending a packet. */
+static inline u8 ip_sendmsg_scope(const struct inet_sock *inet,
+				  const struct ipcm_cookie *ipc,
+				  const struct msghdr *msg)
+{
+	if (sock_flag(&inet->sk, SOCK_LOCALROUTE) ||
+	    msg->msg_flags & MSG_DONTROUTE ||
+	    (ipc->opt && ipc->opt->opt.is_strictroute))
+		return RT_SCOPE_LINK;
+
+	return RT_SCOPE_UNIVERSE;
+}
+
 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 {
 	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);

net/ipv4/ping.c

@@ -705,7 +705,7 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	struct ip_options_data opt_copy;
 	int free = 0;
 	__be32 saddr, daddr, faddr;
-	u8  tos;
+	u8 tos, scope;
 	int err;
 
 	pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
@@ -769,11 +769,7 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		faddr = ipc.opt->opt.faddr;
 	}
 	tos = get_rttos(&ipc, inet);
-	if (sock_flag(sk, SOCK_LOCALROUTE) ||
-	    (msg->msg_flags & MSG_DONTROUTE) ||
-	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
-		tos |= RTO_ONLINK;
-	}
+	scope = ip_sendmsg_scope(inet, &ipc, msg);
 
 	if (ipv4_is_multicast(daddr)) {
 		if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
@@ -783,10 +779,9 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	} else if (!ipc.oif)
 		ipc.oif = inet->uc_index;
 
-	flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
-			   RT_SCOPE_UNIVERSE, sk->sk_protocol,
-			   inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
-			   sk->sk_uid);
+	flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos, scope,
+			   sk->sk_protocol, inet_sk_flowi_flags(sk), faddr,
+			   saddr, 0, 0, sk->sk_uid);
 
 	fl4.fl4_icmp_type = user_icmph.type;
 	fl4.fl4_icmp_code = user_icmph.code;