1 files changed, 49 insertions, 0 deletions
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index ea7c4d64a00a..d5fd3e799f86 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -758,6 +758,27 @@ static int ipv6_renew_option(void *ohdr,
 	return 0;
 }
 
+/**
+ * ipv6_renew_options - replace a specific ext hdr with a new one.
+ *
+ * @sk: sock from which to allocate memory
+ * @opt: original options
+ * @newtype: option type to replace in @opt
+ * @newopt: new option of type @newtype to replace (user-mem)
+ * @newoptlen: length of @newopt
+ *
+ * Returns a new set of options which is a copy of @opt with the
+ * option type @newtype replaced with @newopt.
+ *
+ * @opt may be NULL, in which case a new set of options is returned
+ * containing just @newopt.
+ *
+ * @newopt may be NULL, in which case the specified option type is
+ * not copied into the new set of options.
+ *
+ * The new set of options is allocated from the socket option memory
+ * buffer of @sk.
+ */
 struct ipv6_txoptions *
 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
 		   int newtype,
@@ -830,6 +851,34 @@ out:
 	return ERR_PTR(err);
 }
 
+/**
+ * ipv6_renew_options_kern - replace a specific ext hdr with a new one.
+ *
+ * @sk: sock from which to allocate memory
+ * @opt: original options
+ * @newtype: option type to replace in @opt
+ * @newopt: new option of type @newtype to replace (kernel-mem)
+ * @newoptlen: length of @newopt
+ *
+ * See ipv6_renew_options().  The difference is that @newopt is
+ * kernel memory, rather than user memory.
+ */
+struct ipv6_txoptions *
+ipv6_renew_options_kern(struct sock *sk, struct ipv6_txoptions *opt,
+			int newtype, struct ipv6_opt_hdr *newopt,
+			int newoptlen)
+{
+	struct ipv6_txoptions *ret_val;
+	const mm_segment_t old_fs = get_fs();
+
+	set_fs(KERNEL_DS);
+	ret_val = ipv6_renew_options(sk, opt, newtype,
+				     (struct ipv6_opt_hdr __user *)newopt,
+				     newoptlen);
+	set_fs(old_fs);
+	return ret_val;
+}
+
 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 					  struct ipv6_txoptions *opt)
 {