netfilter: xt_recent: IPv6 support

This updates xt_recent to support the IPv6 address family.
The new /proc/net/xt_recent directory must be used for this.
The old proc interface can also be configured out.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

Documentation/feature-removal-schedule.txt

@@ -250,6 +250,9 @@ What (Why):
 	- xt_mark match revision 0
 	  (superseded by xt_mark match revision 1)
 
+	- xt_recent: the old ipt_recent proc dir
+	  (superseded by /proc/net/xt_recent)
+
 When:	January 2009 or Linux 2.7.0, whichever comes first
 Why:	Superseded by newer revisions or modules
 Who:	Jan Engelhardt <jengelh@computergmbh.de>

net/netfilter/Kconfig

@@ -743,6 +743,13 @@ config NETFILTER_XT_MATCH_RECENT
 	Short options are available by using 'iptables -m recent -h'
 	Official Website: <http://snowman.net/projects/ipt_recent/>
 
+config NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+	bool 'Enable obsolete /proc/net/ipt_recent'
+	depends on NETFILTER_XT_MATCH_RECENT && PROC_FS
+	---help---
+	This option enables the old /proc/net/ipt_recent interface,
+	which has been obsoleted by /proc/net/xt_recent.
+
 config NETFILTER_XT_MATCH_SCTP
 	tristate  '"sctp" protocol match support (EXPERIMENTAL)'
 	depends on NETFILTER_XTABLES && EXPERIMENTAL

net/netfilter/xt_recent.c

 /*
  * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
+ * Copyright © CC Computer Consultants GmbH, 2007 - 2008
  *
  * 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
@@ -13,6 +14,8 @@
  */
 #include <linux/init.h>
 #include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
@@ -30,9 +33,11 @@
 #include <linux/netfilter/xt_recent.h>
 
 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching for IPv4");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("ipt_recent");
+MODULE_ALIAS("ip6t_recent");
 
 static unsigned int ip_list_tot = 100;
 static unsigned int ip_pkt_list_tot = 20;
@@ -49,14 +54,15 @@ module_param(ip_list_gid, uint, 0400);
 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
 MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
-MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/ipt_recent/* files");
-MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/ipt_recent/* files");
-MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/ipt_recent/* files");
+MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
+MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/xt_recent/* files");
+MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/xt_recent/* files");
 
 struct recent_entry {
 	struct list_head	list;
 	struct list_head	lru_list;
-	__be32			addr;
+	union nf_inet_addr	addr;
+	u_int16_t		family;
 	u_int8_t		ttl;
 	u_int8_t		index;
 	u_int16_t		nstamps;
@@ -67,7 +73,7 @@ struct recent_table {
 	struct list_head	list;
 	char			name[XT_RECENT_NAME_LEN];
 #ifdef CONFIG_PROC_FS
-	struct proc_dir_entry	*proc;
+	struct proc_dir_entry	*proc_old, *proc;
 #endif
 	unsigned int		refcnt;
 	unsigned int		entries;
@@ -80,31 +86,53 @@ static DEFINE_SPINLOCK(recent_lock);
 static DEFINE_MUTEX(recent_mutex);
 
 #ifdef CONFIG_PROC_FS
-static struct proc_dir_entry	*proc_dir;
-static const struct file_operations	recent_fops;
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+static struct proc_dir_entry *proc_old_dir;
+#endif
+static struct proc_dir_entry *recent_proc_dir;
+static const struct file_operations recent_old_fops, recent_mt_fops;
 #endif
 
 static u_int32_t hash_rnd;
-static int hash_rnd_initted;
+static bool hash_rnd_initted;
+
+static unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
+{
+	if (!hash_rnd_initted) {
+		get_random_bytes(&hash_rnd, sizeof(hash_rnd));
+		hash_rnd_initted = true;
+	}
+	return jhash_1word((__force u32)addr->ip, hash_rnd) &
+	       (ip_list_hash_size - 1);
+}
 
-static unsigned int recent_entry_hash(__be32 addr)
+static unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
 {
 	if (!hash_rnd_initted) {
-		get_random_bytes(&hash_rnd, 4);
-		hash_rnd_initted = 1;
+		get_random_bytes(&hash_rnd, sizeof(hash_rnd));
+		hash_rnd_initted = true;
 	}
-	return jhash_1word((__force u32)addr, hash_rnd) & (ip_list_hash_size - 1);
+	return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
+	       (ip_list_hash_size - 1);
 }
 
 static struct recent_entry *
-recent_entry_lookup(const struct recent_table *table, __be32 addr, u_int8_t ttl)
+recent_entry_lookup(const struct recent_table *table,
+		    const union nf_inet_addr *addrp, u_int16_t family,
+		    u_int8_t ttl)
 {
 	struct recent_entry *e;
 	unsigned int h;
 
-	h = recent_entry_hash(addr);
+	if (family == AF_INET)
+		h = recent_entry_hash4(addrp);
+	else
+		h = recent_entry_hash6(addrp);
+
 	list_for_each_entry(e, &table->iphash[h], list)
-		if (e->addr == addr && (ttl == e->ttl || !ttl || !e->ttl))
+		if (e->family == family &&
+		    memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
+		    (ttl == e->ttl || ttl == 0 || e->ttl == 0))
 			return e;
 	return NULL;
 }
@@ -118,7 +146,8 @@ static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
 }
 
 static struct recent_entry *
-recent_entry_init(struct recent_table *t, __be32 addr, u_int8_t ttl)
+recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
+		  u_int16_t family, u_int8_t ttl)
 {
 	struct recent_entry *e;
 
@@ -130,12 +159,16 @@ recent_entry_init(struct recent_table *t, __be32 addr, u_int8_t ttl)
 		    GFP_ATOMIC);
 	if (e == NULL)
 		return NULL;
-	e->addr      = addr;
+	memcpy(&e->addr, addr, sizeof(e->addr));
 	e->ttl       = ttl;
 	e->stamps[0] = jiffies;
 	e->nstamps   = 1;
 	e->index     = 1;
-	list_add_tail(&e->list, &t->iphash[recent_entry_hash(addr)]);
+	e->family    = family;
+	if (family == AF_INET)
+		list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
+	else
+		list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
 	list_add_tail(&e->lru_list, &t->lru_list);
 	t->entries++;
 	return e;
@@ -179,28 +212,42 @@ recent_mt(const struct sk_buff *skb, const struct net_device *in,
 	const struct xt_recent_mtinfo *info = matchinfo;
 	struct recent_table *t;
 	struct recent_entry *e;
-	__be32 addr;
+	union nf_inet_addr addr = {};
 	u_int8_t ttl;
 	bool ret = info->invert;
 
+	if (match->family == AF_INET) {
+		const struct iphdr *iph = ip_hdr(skb);
+
 		if (info->side == XT_RECENT_DEST)
-		addr = ip_hdr(skb)->daddr;
+			addr.ip = iph->daddr;
 		else
-		addr = ip_hdr(skb)->saddr;
+			addr.ip = iph->saddr;
+
+		ttl = iph->ttl;
+	} else {
+		const struct ipv6hdr *iph = ipv6_hdr(skb);
+
+		if (info->side == XT_RECENT_DEST)
+			memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
+		else
+			memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
+
+		ttl = iph->hop_limit;
+	}
 
-	ttl = ip_hdr(skb)->ttl;
 	/* use TTL as seen before forwarding */
 	if (out && !skb->sk)
 		ttl++;
 
 	spin_lock_bh(&recent_lock);
 	t = recent_table_lookup(info->name);
-	e = recent_entry_lookup(t, addr,
-				info->check_set & XT_RECENT_TTL ? ttl : 0);
+	e = recent_entry_lookup(t, &addr, match->family,
+				(info->check_set & XT_RECENT_TTL) ? ttl : 0);
 	if (e == NULL) {
 		if (!(info->check_set & XT_RECENT_SET))
 			goto out;
-		e = recent_entry_init(t, addr, ttl);
+		e = recent_entry_init(t, &addr, match->family, ttl);
 		if (e == NULL)
 			*hotdrop = true;
 		ret = !ret;
@@ -277,11 +324,24 @@ recent_mt_check(const char *tablename, const void *ip,
 	for (i = 0; i < ip_list_hash_size; i++)
 		INIT_LIST_HEAD(&t->iphash[i]);
 #ifdef CONFIG_PROC_FS
-	t->proc = proc_create(t->name, ip_list_perms, proc_dir, &recent_fops);
+	t->proc = proc_create(t->name, ip_list_perms, recent_proc_dir,
+		  &recent_mt_fops);
 	if (t->proc == NULL) {
 		kfree(t);
 		goto out;
 	}
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+	t->proc_old = proc_create(t->name, ip_list_perms, proc_old_dir,
+		      &recent_old_fops);
+	if (t->proc_old == NULL) {
+		remove_proc_entry(t->name, proc_old_dir);
+		kfree(t);
+		goto out;
+	}
+	t->proc_old->uid   = ip_list_uid;
+	t->proc_old->gid   = ip_list_gid;
+	t->proc_old->data  = t;
+#endif
 	t->proc->uid       = ip_list_uid;
 	t->proc->gid       = ip_list_gid;
 	t->proc->data      = t;
@@ -307,7 +367,10 @@ static void recent_mt_destroy(const struct xt_match *match, void *matchinfo)
 		list_del(&t->list);
 		spin_unlock_bh(&recent_lock);
 #ifdef CONFIG_PROC_FS
-		remove_proc_entry(t->name, proc_dir);
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+		remove_proc_entry(t->name, proc_old_dir);
+#endif
+		remove_proc_entry(t->name, recent_proc_dir);
 #endif
 		recent_table_flush(t);
 		kfree(t);
@@ -317,7 +380,7 @@ static void recent_mt_destroy(const struct xt_match *match, void *matchinfo)
 
 #ifdef CONFIG_PROC_FS
 struct recent_iter_state {
-	struct recent_table	*table;
+	const struct recent_table *table;
 	unsigned int		bucket;
 };
 
@@ -342,8 +405,8 @@ static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
 	struct recent_iter_state *st = seq->private;
 	const struct recent_table *t = st->table;
-	struct recent_entry *e = v;
-	struct list_head *head = e->list.next;
+	const struct recent_entry *e = v;
+	const struct list_head *head = e->list.next;
 
 	while (head == &t->iphash[st->bucket]) {
 		if (++st->bucket >= ip_list_hash_size)
@@ -366,8 +429,14 @@ static int recent_seq_show(struct seq_file *seq, void *v)
 	unsigned int i;
 
 	i = (e->index - 1) % ip_pkt_list_tot;
-	seq_printf(seq, "src=%u.%u.%u.%u ttl: %u last_seen: %lu oldest_pkt: %u",
-		   NIPQUAD(e->addr), e->ttl, e->stamps[i], e->index);
+	if (e->family == AF_INET)
+		seq_printf(seq, "src=" NIPQUAD_FMT " ttl: %u last_seen: %lu "
+			   "oldest_pkt: %u", NIPQUAD(e->addr.ip), e->ttl,
+			   e->stamps[i], e->index);
+	else
+		seq_printf(seq, "src=" NIP6_FMT " ttl: %u last_seen: %lu "
+			   "oldest_pkt: %u", NIP6(e->addr.in6), e->ttl,
+			   e->stamps[i], e->index);
 	for (i = 0; i < e->nstamps; i++)
 		seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
 	seq_printf(seq, "\n");
@@ -394,7 +463,21 @@ static int recent_seq_open(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static ssize_t recent_proc_write(struct file *file, const char __user *input,
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+static int recent_old_seq_open(struct inode *inode, struct file *filp)
+{
+	static bool warned_of_old;
+
+	if (unlikely(!warned_of_old)) {
+		printk(KERN_INFO KBUILD_MODNAME ": Use of /proc/net/ipt_recent"
+		       " is deprecated; use /proc/net/xt_recent.\n");
+		warned_of_old = true;
+	}
+	return recent_seq_open(inode, filp);
+}
+
+static ssize_t recent_old_proc_write(struct file *file,
+				     const char __user *input,
 				     size_t size, loff_t *loff)
 {
 	const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
@@ -408,6 +491,7 @@ static ssize_t recent_proc_write(struct file *file, const char __user *input,
 		size = sizeof(buf);
 	if (copy_from_user(buf, input, size))
 		return -EFAULT;
+
 	while (isspace(*c))
 		c++;
 
@@ -435,10 +519,10 @@ static ssize_t recent_proc_write(struct file *file, const char __user *input,
 	addr = in_aton(c);
 
 	spin_lock_bh(&recent_lock);
-	e = recent_entry_lookup(t, addr, 0);
+	e = recent_entry_lookup(t, (const void *)&addr, PF_INET, 0);
 	if (e == NULL) {
 		if (add)
-			recent_entry_init(t, addr, 0);
+			recent_entry_init(t, (const void *)&addr, PF_INET, 0);
 	} else {
 		if (add)
 			recent_entry_update(t, e);
@@ -449,23 +533,118 @@ static ssize_t recent_proc_write(struct file *file, const char __user *input,
 	return size;
 }
 
-static const struct file_operations recent_fops = {
+static const struct file_operations recent_old_fops = {
+	.open		= recent_old_seq_open,
+	.read		= seq_read,
+	.write		= recent_old_proc_write,
+	.release	= seq_release_private,
+	.owner		= THIS_MODULE,
+};
+#endif
+
+static ssize_t
+recent_mt_proc_write(struct file *file, const char __user *input,
+		     size_t size, loff_t *loff)
+{
+	const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
+	struct recent_table *t = pde->data;
+	struct recent_entry *e;
+	char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
+	const char *c = buf;
+	union nf_inet_addr addr;
+	u_int16_t family;
+	bool add, succ;
+
+	if (size == 0)
+		return 0;
+	if (size > sizeof(buf))
+		size = sizeof(buf);
+	if (copy_from_user(buf, input, size) != 0)
+		return -EFAULT;
+
+	/* Strict protocol! */
+	if (*loff != 0)
+		return -ESPIPE;
+	switch (*c) {
+	case '/': /* flush table */
+		spin_lock_bh(&recent_lock);
+		recent_table_flush(t);
+		spin_unlock_bh(&recent_lock);
+		return size;
+	case '-': /* remove address */
+		add = false;
+		break;
+	case '+': /* add address */
+		add = true;
+		break;
+	default:
+		printk(KERN_INFO KBUILD_MODNAME ": Need +ip, -ip or /\n");
+		return -EINVAL;
+	}
+
+	++c;
+	--size;
+	if (strnchr(c, size, ':') != NULL) {
+		family = AF_INET6;
+		succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
+	} else {
+		family = AF_INET;
+		succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
+	}
+
+	if (!succ) {
+		printk(KERN_INFO KBUILD_MODNAME ": illegal address written "
+		       "to procfs\n");
+		return -EINVAL;
+	}
+
+	spin_lock_bh(&recent_lock);
+	e = recent_entry_lookup(t, &addr, family, 0);
+	if (e == NULL) {
+		if (add)
+			recent_entry_init(t, &addr, family, 0);
+	} else {
+		if (add)
+			recent_entry_update(t, e);
+		else
+			recent_entry_remove(t, e);
+	}
+	spin_unlock_bh(&recent_lock);
+	/* Note we removed one above */
+	*loff += size + 1;
+	return size + 1;
+}
+
+static const struct file_operations recent_mt_fops = {
 	.open    = recent_seq_open,
 	.read    = seq_read,
-	.write		= recent_proc_write,
+	.write   = recent_mt_proc_write,
 	.release = seq_release_private,
 	.owner   = THIS_MODULE,
 };
 #endif /* CONFIG_PROC_FS */
 
-static struct xt_match recent_mt_reg __read_mostly = {
+static struct xt_match recent_mt_reg[] __read_mostly = {
+	{
 		.name       = "recent",
+		.revision   = 0,
 		.family     = AF_INET,
 		.match      = recent_mt,
 		.matchsize  = sizeof(struct xt_recent_mtinfo),
 		.checkentry = recent_mt_check,
 		.destroy    = recent_mt_destroy,
 		.me         = THIS_MODULE,
+	},
+	{
+		.name       = "recent",
+		.revision   = 0,
+		.family     = AF_INET6,
+		.match      = recent_mt,
+		.matchsize  = sizeof(struct xt_recent_mtinfo),
+		.checkentry = recent_mt_check,
+		.destroy    = recent_mt_destroy,
+		.me         = THIS_MODULE,
+	},
 };
 
 static int __init recent_mt_init(void)
@@ -476,15 +655,25 @@ static int __init recent_mt_init(void)
 		return -EINVAL;
 	ip_list_hash_size = 1 << fls(ip_list_tot);
 
-	err = xt_register_match(&recent_mt_reg);
+	err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 #ifdef CONFIG_PROC_FS
 	if (err)
 		return err;
-	proc_dir = proc_mkdir("ipt_recent", init_net.proc_net);
-	if (proc_dir == NULL) {
-		xt_unregister_match(&recent_mt_reg);
+	recent_proc_dir = proc_mkdir("xt_recent", init_net.proc_net);
+	if (recent_proc_dir == NULL) {
+		xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
+		err = -ENOMEM;
+	}
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+	if (err < 0)
+		return err;
+	proc_old_dir = proc_mkdir("ipt_recent", init_net.proc_net);
+	if (proc_old_dir == NULL) {
+		remove_proc_entry("xt_recent", init_net.proc_net);
+		xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 		err = -ENOMEM;
 	}
+#endif
 #endif
 	return err;
 }
@@ -492,9 +681,12 @@ static int __init recent_mt_init(void)
 static void __exit recent_mt_exit(void)
 {
 	BUG_ON(!list_empty(&tables));
-	xt_unregister_match(&recent_mt_reg);
+	xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 #ifdef CONFIG_PROC_FS
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
 	remove_proc_entry("ipt_recent", init_net.proc_net);
+#endif
+	remove_proc_entry("xt_recent", init_net.proc_net);
 #endif
 }