ipv6: ipcm6_cookie initializer

Initialize the cookie in one location to reduce code duplication and
avoid bugs from inconsistent initialization, such as that fixed in
commit 9887cba199 ("ip: limit use of gso_size to udp").

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -301,6 +301,25 @@ struct ipcm6_cookie {
 	__u16 gso_size;
 };
 
+static inline void ipcm6_init(struct ipcm6_cookie *ipc6)
+{
+	*ipc6 = (struct ipcm6_cookie) {
+		.hlimit = -1,
+		.tclass = -1,
+		.dontfrag = -1,
+	};
+}
+
+static inline void ipcm6_init_sk(struct ipcm6_cookie *ipc6,
+				 const struct ipv6_pinfo *np)
+{
+	*ipc6 = (struct ipcm6_cookie) {
+		.hlimit = -1,
+		.tclass = np->tclass,
+		.dontfrag = np->dontfrag,
+	};
+}
+
 static inline struct ipv6_txoptions *txopt_get(const struct ipv6_pinfo *np)
 {
 	struct ipv6_txoptions *opt;

net/ipv6/icmp.c

@@ -545,7 +545,7 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
 	else if (!fl6.flowi6_oif)
 		fl6.flowi6_oif = np->ucast_oif;
 
-	ipc6.tclass = np->tclass;
+	ipcm6_init_sk(&ipc6, np);
 	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 
 	dst = icmpv6_route_lookup(net, skb, sk, &fl6);
@@ -553,8 +553,6 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
 		goto out;
 
 	ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
-	ipc6.dontfrag = np->dontfrag;
-	ipc6.opt = NULL;
 
 	msg.skb = skb;
 	msg.offset = skb_network_offset(skb);
@@ -726,10 +724,9 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
 	msg.offset = 0;
 	msg.type = ICMPV6_ECHO_REPLY;
 
+	ipcm6_init_sk(&ipc6, np);
 	ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 	ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));
-	ipc6.dontfrag = np->dontfrag;
-	ipc6.opt = NULL;
 
 	if (ip6_append_data(sk, icmpv6_getfrag, &msg,
 			    skb->len + sizeof(struct icmp6hdr),

net/ipv6/ping.c

@@ -119,7 +119,7 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	fl6.fl6_icmp_code = user_icmph.icmp6_code;
 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
-	ipc6.tclass = np->tclass;
+	ipcm6_init_sk(&ipc6, np);
 	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 
 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, daddr, false);
@@ -142,8 +142,6 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	pfh.family = AF_INET6;
 
 	ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
-	ipc6.dontfrag = np->dontfrag;
-	ipc6.opt = NULL;
 
 	lock_sock(sk);
 	err = ip6_append_data(sk, ping_getfrag, &pfh, len,

net/ipv6/raw.c

@@ -791,10 +791,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	fl6.flowi6_mark = sk->sk_mark;
 	fl6.flowi6_uid = sk->sk_uid;
 
-	ipc6.hlimit = -1;
+	ipcm6_init(&ipc6);
-	ipc6.tclass = -1;
-	ipc6.dontfrag = -1;
-	ipc6.opt = NULL;
 
 	if (sin6) {
 		if (addr_len < SIN6_LEN_RFC2133)

net/ipv6/udp.c

@@ -1143,9 +1143,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
 	struct sockcm_cookie sockc;
 
-	ipc6.hlimit = -1;
+	ipcm6_init(&ipc6);
-	ipc6.tclass = -1;
-	ipc6.dontfrag = -1;
 	ipc6.gso_size = up->gso_size;
 	sockc.tsflags = sk->sk_tsflags;
 	sockc.transmit_time = 0;

net/l2tp/l2tp_ip6.c

@@ -525,9 +525,7 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	fl6.flowi6_mark = sk->sk_mark;
 	fl6.flowi6_uid = sk->sk_uid;
 
-	ipc6.hlimit = -1;
+	ipcm6_init(&ipc6);
-	ipc6.tclass = -1;
-	ipc6.dontfrag = -1;
 
 	if (lsa) {
 		if (addr_len < SIN6_LEN_RFC2133)