net/ipv6: factor out MCAST_MSFILTER getsockopt helpers

Factor out one helper each for getting the native and compat
version of the MCAST_MSFILTER option.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ipv6_sockglue.c

@@ -1071,33 +1071,12 @@ static int ipv6_getsockopt_sticky(struct sock *sk, struct ipv6_txoptions *opt,
 	return len;
 }
 
-static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
-		    char __user *optval, int __user *optlen, unsigned int flags)
+static int ipv6_get_msfilter(struct sock *sk, void __user *optval,
+		int __user *optlen, int len)
 {
-	struct ipv6_pinfo *np = inet6_sk(sk);
-	int len;
-	int val;
-
-	if (ip6_mroute_opt(optname))
-		return ip6_mroute_getsockopt(sk, optname, optval, optlen);
-
-	if (get_user(len, optlen))
-		return -EFAULT;
-	switch (optname) {
-	case IPV6_ADDRFORM:
-		if (sk->sk_protocol != IPPROTO_UDP &&
-		    sk->sk_protocol != IPPROTO_UDPLITE &&
-		    sk->sk_protocol != IPPROTO_TCP)
-			return -ENOPROTOOPT;
-		if (sk->sk_state != TCP_ESTABLISHED)
-			return -ENOTCONN;
-		val = sk->sk_family;
-		break;
-	case MCAST_MSFILTER:
-	{
-		struct group_filter __user *p = (void __user *)optval;
-		struct group_filter gsf;
 	const int size0 = offsetof(struct group_filter, gf_slist);
+	struct group_filter __user *p = optval;
+	struct group_filter gsf;
 	int num;
 	int err;
 
@@ -1119,8 +1098,74 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
 	}
 	release_sock(sk);
 	return err;
-	}
+}
 
+#ifdef CONFIG_COMPAT
+static int compat_ipv6_get_msfilter(struct sock *sk, void __user *optval,
+		int __user *optlen)
+{
+	const int size0 = offsetof(struct compat_group_filter, gf_slist);
+	struct compat_group_filter __user *p = optval;
+	struct compat_group_filter gf32;
+	struct group_filter gf;
+	int len, err;
+	int num;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+	if (len < size0)
+		return -EINVAL;
+
+	if (copy_from_user(&gf32, p, size0))
+		return -EFAULT;
+	gf.gf_interface = gf32.gf_interface;
+	gf.gf_fmode = gf32.gf_fmode;
+	num = gf.gf_numsrc = gf32.gf_numsrc;
+	gf.gf_group = gf32.gf_group;
+
+	if (gf.gf_group.ss_family != AF_INET6)
+		return -EADDRNOTAVAIL;
+
+	lock_sock(sk);
+	err = ip6_mc_msfget(sk, &gf, p->gf_slist);
+	release_sock(sk);
+	if (err)
+		return err;
+	if (num > gf.gf_numsrc)
+		num = gf.gf_numsrc;
+	len = GROUP_FILTER_SIZE(num) - (sizeof(gf)-sizeof(gf32));
+	if (put_user(len, optlen) ||
+	    put_user(gf.gf_fmode, &p->gf_fmode) ||
+	    put_user(gf.gf_numsrc, &p->gf_numsrc))
+		return -EFAULT;
+	return 0;
+}
+#endif
+
+static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
+		    char __user *optval, int __user *optlen, unsigned int flags)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	int len;
+	int val;
+
+	if (ip6_mroute_opt(optname))
+		return ip6_mroute_getsockopt(sk, optname, optval, optlen);
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+	switch (optname) {
+	case IPV6_ADDRFORM:
+		if (sk->sk_protocol != IPPROTO_UDP &&
+		    sk->sk_protocol != IPPROTO_UDPLITE &&
+		    sk->sk_protocol != IPPROTO_TCP)
+			return -ENOPROTOOPT;
+		if (sk->sk_state != TCP_ESTABLISHED)
+			return -ENOTCONN;
+		val = sk->sk_family;
+		break;
+	case MCAST_MSFILTER:
+		return ipv6_get_msfilter(sk, optval, optlen, len);
 	case IPV6_2292PKTOPTIONS:
 	{
 		struct msghdr msg;
@@ -1481,44 +1526,8 @@ int compat_ipv6_getsockopt(struct sock *sk, int level, int optname,
 	if (level != SOL_IPV6)
 		return -ENOPROTOOPT;
 
-	if (optname == MCAST_MSFILTER) {
-		const int size0 = offsetof(struct compat_group_filter, gf_slist);
-		struct compat_group_filter __user *p = (void __user *)optval;
-		struct compat_group_filter gf32;
-		struct group_filter gf;
-		int ulen, err;
-		int num;
-
-		if (get_user(ulen, optlen))
-			return -EFAULT;
-
-		if (ulen < size0)
-			return -EINVAL;
-
-		if (copy_from_user(&gf32, p, size0))
-			return -EFAULT;
-
-		gf.gf_interface = gf32.gf_interface;
-		gf.gf_fmode = gf32.gf_fmode;
-		num = gf.gf_numsrc = gf32.gf_numsrc;
-		gf.gf_group = gf32.gf_group;
-
-		if (gf.gf_group.ss_family != AF_INET6)
-			return -EADDRNOTAVAIL;
-		lock_sock(sk);
-		err = ip6_mc_msfget(sk, &gf, p->gf_slist);
-		release_sock(sk);
-		if (err)
-			return err;
-		if (num > gf.gf_numsrc)
-			num = gf.gf_numsrc;
-		ulen = GROUP_FILTER_SIZE(num) - (sizeof(gf)-sizeof(gf32));
-		if (put_user(ulen, optlen) ||
-		    put_user(gf.gf_fmode, &p->gf_fmode) ||
-		    put_user(gf.gf_numsrc, &p->gf_numsrc))
-			return -EFAULT;
-		return 0;
-	}
+	if (optname == MCAST_MSFILTER)
+		return compat_ipv6_get_msfilter(sk, optval, optlen);
 
 	err = do_ipv6_getsockopt(sk, level, optname, optval, optlen,
 				 MSG_CMSG_COMPAT);