1 files changed, 612 insertions, 0 deletions

diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c
new file mode 100644
index 0000000..37a703b
--- /dev/null
+++ b/net/netfilter/nf_conntrack_expect.c
@@ -0,0 +1,612 @@
+/* Expectation handling for nf_conntrack. */
+
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
+ *
+ * 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.
+ */
+
+#include <linux/types.h>
+#include <linux/netfilter.h>
+#include <linux/skbuff.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stddef.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/percpu.h>
+#include <linux/kernel.h>
+#include <linux/jhash.h>
+#include <net/net_namespace.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_tuple.h>
+
+unsigned int nf_ct_expect_hsize __read_mostly;
+EXPORT_SYMBOL_GPL(nf_ct_expect_hsize);
+
+static unsigned int nf_ct_expect_hash_rnd __read_mostly;
+unsigned int nf_ct_expect_max __read_mostly;
+static int nf_ct_expect_hash_rnd_initted __read_mostly;
+
+static struct kmem_cache *nf_ct_expect_cachep __read_mostly;
+
+/* nf_conntrack_expect helper functions */
+void nf_ct_unlink_expect(struct nf_conntrack_expect *exp)
+{
+	struct nf_conn_help *master_help = nfct_help(exp->master);
+	struct net *net = nf_ct_exp_net(exp);
+
+	NF_CT_ASSERT(master_help);
+	NF_CT_ASSERT(!timer_pending(&exp->timeout));
+
+	hlist_del_rcu(&exp->hnode);
+	net->ct.expect_count--;
+
+	hlist_del(&exp->lnode);
+	master_help->expecting[exp->class]--;
+	nf_ct_expect_put(exp);
+
+	NF_CT_STAT_INC(net, expect_delete);
+}
+EXPORT_SYMBOL_GPL(nf_ct_unlink_expect);
+
+static void nf_ct_expectation_timed_out(unsigned long ul_expect)
+{
+	struct nf_conntrack_expect *exp = (void *)ul_expect;
+
+	spin_lock_bh(&nf_conntrack_lock);
+	nf_ct_unlink_expect(exp);
+	spin_unlock_bh(&nf_conntrack_lock);
+	nf_ct_expect_put(exp);
+}
+
+static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple)
+{
+	unsigned int hash;
+
+	if (unlikely(!nf_ct_expect_hash_rnd_initted)) {
+		get_random_bytes(&nf_ct_expect_hash_rnd, 4);
+		nf_ct_expect_hash_rnd_initted = 1;
+	}
+
+	hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
+		      (((tuple->dst.protonum ^ tuple->src.l3num) << 16) |
+		       (__force __u16)tuple->dst.u.all) ^ nf_ct_expect_hash_rnd);
+	return ((u64)hash * nf_ct_expect_hsize) >> 32;
+}
+
+struct nf_conntrack_expect *
+__nf_ct_expect_find(struct net *net, const struct nf_conntrack_tuple *tuple)
+{
+	struct nf_conntrack_expect *i;
+	struct hlist_node *n;
+	unsigned int h;
+
+	if (!net->ct.expect_count)
+		return NULL;
+
+	h = nf_ct_expect_dst_hash(tuple);
+	hlist_for_each_entry_rcu(i, n, &net->ct.expect_hash[h], hnode) {
+		if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask))
+			return i;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(__nf_ct_expect_find);
+
+/* Just find a expectation corresponding to a tuple. */
+struct nf_conntrack_expect *
+nf_ct_expect_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
+{
+	struct nf_conntrack_expect *i;
+
+	rcu_read_lock();
+	i = __nf_ct_expect_find(net, tuple);
+	if (i && !atomic_inc_not_zero(&i->use))
+		i = NULL;
+	rcu_read_unlock();
+
+	return i;
+}
+EXPORT_SYMBOL_GPL(nf_ct_expect_find_get);
+
+/* If an expectation for this connection is found, it gets delete from
+ * global list then returned. */
+struct nf_conntrack_expect *
+nf_ct_find_expectation(struct net *net, const struct nf_conntrack_tuple *tuple)
+{
+	struct nf_conntrack_expect *i, *exp = NULL;
+	struct hlist_node *n;
+	unsigned int h;
+
+	if (!net->ct.expect_count)
+		return NULL;
+
+	h = nf_ct_expect_dst_hash(tuple);
+	hlist_for_each_entry(i, n, &net->ct.expect_hash[h], hnode) {
+		if (!(i->flags & NF_CT_EXPECT_INACTIVE) &&
+		    nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask)) {
+			exp = i;
+			break;
+		}
+	}
+	if (!exp)
+		return NULL;
+
+	/* If master is not in hash table yet (ie. packet hasn't left
+	   this machine yet), how can other end know about expected?
+	   Hence these are not the droids you are looking for (if
+	   master ct never got confirmed, we'd hold a reference to it
+	   and weird things would happen to future packets). */
+	if (!nf_ct_is_confirmed(exp->master))
+		return NULL;
+
+	if (exp->flags & NF_CT_EXPECT_PERMANENT) {
+		atomic_inc(&exp->use);
+		return exp;
+	} else if (del_timer(&exp->timeout)) {
+		nf_ct_unlink_expect(exp);
+		return exp;
+	}
+
+	return NULL;
+}
+
+/* delete all expectations for this conntrack */
+void nf_ct_remove_expectations(struct nf_conn *ct)
+{
+	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_conntrack_expect *exp;
+	struct hlist_node *n, *next;
+
+	/* Optimization: most connection never expect any others. */
+	if (!help)
+		return;
+
+	hlist_for_each_entry_safe(exp, n, next, &help->expectations, lnode) {
+		if (del_timer(&exp->timeout)) {
+			nf_ct_unlink_expect(exp);
+			nf_ct_expect_put(exp);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(nf_ct_remove_expectations);
+
+/* Would two expected things clash? */
+static inline int expect_clash(const struct nf_conntrack_expect *a,
+			       const struct nf_conntrack_expect *b)
+{
+	/* Part covered by intersection of masks must be unequal,
+	   otherwise they clash */
+	struct nf_conntrack_tuple_mask intersect_mask;
+	int count;
+
+	intersect_mask.src.u.all = a->mask.src.u.all & b->mask.src.u.all;
+
+	for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){
+		intersect_mask.src.u3.all[count] =
+			a->mask.src.u3.all[count] & b->mask.src.u3.all[count];
+	}
+
+	return nf_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask);
+}
+
+static inline int expect_matches(const struct nf_conntrack_expect *a,
+				 const struct nf_conntrack_expect *b)
+{
+	return a->master == b->master && a->class == b->class
+		&& nf_ct_tuple_equal(&a->tuple, &b->tuple)
+		&& nf_ct_tuple_mask_equal(&a->mask, &b->mask);
+}
+
+/* Generally a bad idea to call this: could have matched already. */
+void nf_ct_unexpect_related(struct nf_conntrack_expect *exp)
+{
+	spin_lock_bh(&nf_conntrack_lock);
+	if (del_timer(&exp->timeout)) {
+		nf_ct_unlink_expect(exp);
+		nf_ct_expect_put(exp);
+	}
+	spin_unlock_bh(&nf_conntrack_lock);
+}
+EXPORT_SYMBOL_GPL(nf_ct_unexpect_related);
+
+/* We don't increase the master conntrack refcount for non-fulfilled
+ * conntracks. During the conntrack destruction, the expectations are
+ * always killed before the conntrack itself */
+struct nf_conntrack_expect *nf_ct_expect_alloc(struct nf_conn *me)
+{
+	struct nf_conntrack_expect *new;
+
+	new = kmem_cache_alloc(nf_ct_expect_cachep, GFP_ATOMIC);
+	if (!new)
+		return NULL;
+
+	new->master = me;
+	atomic_set(&new->use, 1);
+	INIT_RCU_HEAD(&new->rcu);
+	return new;
+}
+EXPORT_SYMBOL_GPL(nf_ct_expect_alloc);
+
+void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class,
+		       u_int8_t family,
+		       const union nf_inet_addr *saddr,
+		       const union nf_inet_addr *daddr,
+		       u_int8_t proto, const __be16 *src, const __be16 *dst)
+{
+	int len;
+
+	if (family == AF_INET)
+		len = 4;
+	else
+		len = 16;
+
+	exp->flags = 0;
+	exp->class = class;
+	exp->expectfn = NULL;
+	exp->helper = NULL;
+	exp->tuple.src.l3num = family;
+	exp->tuple.dst.protonum = proto;
+
+	if (saddr) {
+		memcpy(&exp->tuple.src.u3, saddr, len);
+		if (sizeof(exp->tuple.src.u3) > len)
+			/* address needs to be cleared for nf_ct_tuple_equal */
+			memset((void *)&exp->tuple.src.u3 + len, 0x00,
+			       sizeof(exp->tuple.src.u3) - len);
+		memset(&exp->mask.src.u3, 0xFF, len);
+		if (sizeof(exp->mask.src.u3) > len)
+			memset((void *)&exp->mask.src.u3 + len, 0x00,
+			       sizeof(exp->mask.src.u3) - len);
+	} else {
+		memset(&exp->tuple.src.u3, 0x00, sizeof(exp->tuple.src.u3));
+		memset(&exp->mask.src.u3, 0x00, sizeof(exp->mask.src.u3));
+	}
+
+	if (src) {
+		exp->tuple.src.u.all = *src;
+		exp->mask.src.u.all = htons(0xFFFF);
+	} else {
+		exp->tuple.src.u.all = 0;
+		exp->mask.src.u.all = 0;
+	}
+
+	memcpy(&exp->tuple.dst.u3, daddr, len);
+	if (sizeof(exp->tuple.dst.u3) > len)
+		/* address needs to be cleared for nf_ct_tuple_equal */
+		memset((void *)&exp->tuple.dst.u3 + len, 0x00,
+		       sizeof(exp->tuple.dst.u3) - len);
+
+	exp->tuple.dst.u.all = *dst;
+}
+EXPORT_SYMBOL_GPL(nf_ct_expect_init);
+
+static void nf_ct_expect_free_rcu(struct rcu_head *head)
+{
+	struct nf_conntrack_expect *exp;
+
+	exp = container_of(head, struct nf_conntrack_expect, rcu);
+	kmem_cache_free(nf_ct_expect_cachep, exp);
+}
+
+void nf_ct_expect_put(struct nf_conntrack_expect *exp)
+{
+	if (atomic_dec_and_test(&exp->use))
+		call_rcu(&exp->rcu, nf_ct_expect_free_rcu);
+}
+EXPORT_SYMBOL_GPL(nf_ct_expect_put);
+
+static void nf_ct_expect_insert(struct nf_conntrack_expect *exp)
+{
+	struct nf_conn_help *master_help = nfct_help(exp->master);
+	struct net *net = nf_ct_exp_net(exp);
+	const struct nf_conntrack_expect_policy *p;
+	unsigned int h = nf_ct_expect_dst_hash(&exp->tuple);
+
+	atomic_inc(&exp->use);
+
+	hlist_add_head(&exp->lnode, &master_help->expectations);
+	master_help->expecting[exp->class]++;
+
+	hlist_add_head_rcu(&exp->hnode, &net->ct.expect_hash[h]);
+	net->ct.expect_count++;
+
+	setup_timer(&exp->timeout, nf_ct_expectation_timed_out,
+		    (unsigned long)exp);
+	p = &master_help->helper->expect_policy[exp->class];
+	exp->timeout.expires = jiffies + p->timeout * HZ;
+	add_timer(&exp->timeout);
+
+	atomic_inc(&exp->use);
+	NF_CT_STAT_INC(net, expect_create);
+}
+
+/* Race with expectations being used means we could have none to find; OK. */
+static void evict_oldest_expect(struct nf_conn *master,
+				struct nf_conntrack_expect *new)
+{
+	struct nf_conn_help *master_help = nfct_help(master);
+	struct nf_conntrack_expect *exp, *last = NULL;
+	struct hlist_node *n;
+
+	hlist_for_each_entry(exp, n, &master_help->expectations, lnode) {
+		if (exp->class == new->class)
+			last = exp;
+	}
+
+	if (last && del_timer(&last->timeout)) {
+		nf_ct_unlink_expect(last);
+		nf_ct_expect_put(last);
+	}
+}
+
+static inline int refresh_timer(struct nf_conntrack_expect *i)
+{
+	struct nf_conn_help *master_help = nfct_help(i->master);
+	const struct nf_conntrack_expect_policy *p;
+
+	if (!del_timer(&i->timeout))
+		return 0;
+
+	p = &master_help->helper->expect_policy[i->class];
+	i->timeout.expires = jiffies + p->timeout * HZ;
+	add_timer(&i->timeout);
+	return 1;
+}
+
+int nf_ct_expect_related(struct nf_conntrack_expect *expect)
+{
+	const struct nf_conntrack_expect_policy *p;
+	struct nf_conntrack_expect *i;
+	struct nf_conn *master = expect->master;
+	struct nf_conn_help *master_help = nfct_help(master);
+	struct net *net = nf_ct_exp_net(expect);
+	struct hlist_node *n;
+	unsigned int h;
+	int ret;
+
+	NF_CT_ASSERT(master_help);
+
+	spin_lock_bh(&nf_conntrack_lock);
+	if (!master_help->helper) {
+		ret = -ESHUTDOWN;
+		goto out;
+	}
+	h = nf_ct_expect_dst_hash(&expect->tuple);
+	hlist_for_each_entry(i, n, &net->ct.expect_hash[h], hnode) {
+		if (expect_matches(i, expect)) {
+			/* Refresh timer: if it's dying, ignore.. */
+			if (refresh_timer(i)) {
+				ret = 0;
+				goto out;
+			}
+		} else if (expect_clash(i, expect)) {
+			ret = -EBUSY;
+			goto out;
+		}
+	}
+	/* Will be over limit? */
+	p = &master_help->helper->expect_policy[expect->class];
+	if (p->max_expected &&
+	    master_help->expecting[expect->class] >= p->max_expected) {
+		evict_oldest_expect(master, expect);
+		if (master_help->expecting[expect->class] >= p->max_expected) {
+			ret = -EMFILE;
+			goto out;
+		}
+	}
+
+	if (net->ct.expect_count >= nf_ct_expect_max) {
+		if (net_ratelimit())
+			printk(KERN_WARNING
+			       "nf_conntrack: expectation table full\n");
+		ret = -EMFILE;
+		goto out;
+	}
+
+	nf_ct_expect_insert(expect);
+	nf_ct_expect_event(IPEXP_NEW, expect);
+	ret = 0;
+out:
+	spin_unlock_bh(&nf_conntrack_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_ct_expect_related);
+
+#ifdef CONFIG_PROC_FS
+struct ct_expect_iter_state {
+	struct seq_net_private p;
+	unsigned int bucket;
+};
+
+static struct hlist_node *ct_expect_get_first(struct seq_file *seq)
+{
+	struct net *net = seq_file_net(seq);
+	struct ct_expect_iter_state *st = seq->private;
+	struct hlist_node *n;
+
+	for (st->bucket = 0; st->bucket < nf_ct_expect_hsize; st->bucket++) {
+		n = rcu_dereference(net->ct.expect_hash[st->bucket].first);
+		if (n)
+			return n;
+	}
+	return NULL;
+}
+
+static struct hlist_node *ct_expect_get_next(struct seq_file *seq,
+					     struct hlist_node *head)
+{
+	struct net *net = seq_file_net(seq);
+	struct ct_expect_iter_state *st = seq->private;
+
+	head = rcu_dereference(head->next);
+	while (head == NULL) {
+		if (++st->bucket >= nf_ct_expect_hsize)
+			return NULL;
+		head = rcu_dereference(net->ct.expect_hash[st->bucket].first);
+	}
+	return head;
+}
+
+static struct hlist_node *ct_expect_get_idx(struct seq_file *seq, loff_t pos)
+{
+	struct hlist_node *head = ct_expect_get_first(seq);
+
+	if (head)
+		while (pos && (head = ct_expect_get_next(seq, head)))
+			pos--;
+	return pos ? NULL : head;
+}
+
+static void *exp_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	rcu_read_lock();
+	return ct_expect_get_idx(seq, *pos);
+}
+
+static void *exp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return ct_expect_get_next(seq, v);
+}
+
+static void exp_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static int exp_seq_show(struct seq_file *s, void *v)
+{
+	struct nf_conntrack_expect *expect;
+	struct hlist_node *n = v;
+	char *delim = "";
+
+	expect = hlist_entry(n, struct nf_conntrack_expect, hnode);
+
+	if (expect->timeout.function)
+		seq_printf(s, "%ld ", timer_pending(&expect->timeout)
+			   ? (long)(expect->timeout.expires - jiffies)/HZ : 0);
+	else
+		seq_printf(s, "- ");
+	seq_printf(s, "l3proto = %u proto=%u ",
+		   expect->tuple.src.l3num,
+		   expect->tuple.dst.protonum);
+	print_tuple(s, &expect->tuple,
+		    __nf_ct_l3proto_find(expect->tuple.src.l3num),
+		    __nf_ct_l4proto_find(expect->tuple.src.l3num,
+				       expect->tuple.dst.protonum));
+
+	if (expect->flags & NF_CT_EXPECT_PERMANENT) {
+		seq_printf(s, "PERMANENT");
+		delim = ",";
+	}
+	if (expect->flags & NF_CT_EXPECT_INACTIVE)
+		seq_printf(s, "%sINACTIVE", delim);
+
+	return seq_putc(s, '\n');
+}
+
+static const struct seq_operations exp_seq_ops = {
+	.start = exp_seq_start,
+	.next = exp_seq_next,
+	.stop = exp_seq_stop,
+	.show = exp_seq_show
+};
+
+static int exp_open(struct inode *inode, struct file *file)
+{
+	return seq_open_net(inode, file, &exp_seq_ops,
+			sizeof(struct ct_expect_iter_state));
+}
+
+static const struct file_operations exp_file_ops = {
+	.owner   = THIS_MODULE,
+	.open    = exp_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release_net,
+};
+#endif /* CONFIG_PROC_FS */
+
+static int exp_proc_init(struct net *net)
+{
+#ifdef CONFIG_PROC_FS
+	struct proc_dir_entry *proc;
+
+	proc = proc_net_fops_create(net, "nf_conntrack_expect", 0440, &exp_file_ops);
+	if (!proc)
+		return -ENOMEM;
+#endif /* CONFIG_PROC_FS */
+	return 0;
+}
+
+static void exp_proc_remove(struct net *net)
+{
+#ifdef CONFIG_PROC_FS
+	proc_net_remove(net, "nf_conntrack_expect");
+#endif /* CONFIG_PROC_FS */
+}
+
+module_param_named(expect_hashsize, nf_ct_expect_hsize, uint, 0600);
+
+int nf_conntrack_expect_init(struct net *net)
+{
+	int err = -ENOMEM;
+
+	if (net_eq(net, &init_net)) {
+		if (!nf_ct_expect_hsize) {
+			nf_ct_expect_hsize = nf_conntrack_htable_size / 256;
+			if (!nf_ct_expect_hsize)
+				nf_ct_expect_hsize = 1;
+		}
+		nf_ct_expect_max = nf_ct_expect_hsize * 4;
+	}
+
+	net->ct.expect_count = 0;
+	net->ct.expect_hash = nf_ct_alloc_hashtable(&nf_ct_expect_hsize,
+						  &net->ct.expect_vmalloc);
+	if (net->ct.expect_hash == NULL)
+		goto err1;
+
+	if (net_eq(net, &init_net)) {
+		nf_ct_expect_cachep = kmem_cache_create("nf_conntrack_expect",
+					sizeof(struct nf_conntrack_expect),
+					0, 0, NULL);
+		if (!nf_ct_expect_cachep)
+			goto err2;
+	}
+
+	err = exp_proc_init(net);
+	if (err < 0)
+		goto err3;
+
+	return 0;
+
+err3:
+	if (net_eq(net, &init_net))
+		kmem_cache_destroy(nf_ct_expect_cachep);
+err2:
+	nf_ct_free_hashtable(net->ct.expect_hash, net->ct.expect_vmalloc,
+			     nf_ct_expect_hsize);
+err1:
+	return err;
+}
+
+void nf_conntrack_expect_fini(struct net *net)
+{
+	exp_proc_remove(net);
+	if (net_eq(net, &init_net))
+		kmem_cache_destroy(nf_ct_expect_cachep);
+	nf_ct_free_hashtable(net->ct.expect_hash, net->ct.expect_vmalloc,
+			     nf_ct_expect_hsize);
+}