netfilter: ipset: Support comments for ipset entries in the core.

This adds the core support for having comments on ipset entries.

The comments are stored as standard null-terminated strings in
dynamically allocated memory after being passed to the kernel. As a
result of this, code has been added to the generic destroy function to
iterate all extensions and call that extension's destroy task if the set
has that extension activated, and if such a task is defined.

Signed-off-by: Oliver Smith <oliver@8.c.9.b.0.7.4.0.1.0.0.2.ip6.arpa>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

1 files changed, 57 insertions, 0 deletions

diff --git a/kernel/include/linux/netfilter/ipset/ip_set_comment.h b/kernel/include/linux/netfilter/ipset/ip_set_comment.h
new file mode 100644
index 0000000..21217ea
--- /dev/null
+++ b/kernel/include/linux/netfilter/ipset/ip_set_comment.h
@@ -0,0 +1,57 @@
+#ifndef _IP_SET_COMMENT_H
+#define _IP_SET_COMMENT_H
+
+/* Copyright (C) 2013 Oliver Smith <oliver@8.c.9.b.0.7.4.0.1.0.0.2.ip6.arpa>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifdef __KERNEL__
+
+static inline char*
+ip_set_comment_uget(struct nlattr *tb)
+{
+	return nla_data(tb);
+}
+
+static inline void
+ip_set_init_comment(struct ip_set_comment *comment,
+		    const struct ip_set_ext *ext)
+{
+	size_t len = ext->comment ? strlen(ext->comment) : 0;
+
+	if (unlikely(comment->str)) {
+		kfree(comment->str);
+		comment->str = NULL;
+	}
+	if (!len)
+		return;
+	if (unlikely(len > IPSET_MAX_COMMENT_SIZE))
+		len = IPSET_MAX_COMMENT_SIZE;
+	comment->str = kzalloc(len + 1, GFP_ATOMIC);
+	if (unlikely(!comment->str))
+		return;
+	strlcpy(comment->str, ext->comment, len + 1);
+}
+
+static inline int
+ip_set_put_comment(struct sk_buff *skb, struct ip_set_comment *comment)
+{
+	if (!comment->str)
+		return 0;
+	return nla_put_string(skb, IPSET_ATTR_COMMENT, comment->str);
+}
+
+static inline void
+ip_set_comment_free(struct ip_set_comment *comment)
+{
+	if (unlikely(!comment->str))
+		return;
+	kfree(comment->str);
+	comment->str = NULL;
+}
+
+#endif
+#endif