--- /dev/null
+/*
+ * (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2011 Patrick McHardy <kaber@trash.net>
+ *
+ * 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/module.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/skbuff.h>
+#include <linux/gfp.h>
+#include <net/xfrm.h>
+#include <linux/jhash.h>
+#include <linux/rtnetlink.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_seqadj.h>
+#include <net/netfilter/nf_conntrack_l3proto.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+#include <linux/netfilter/nf_nat.h>
+
+static DEFINE_SPINLOCK(nf_nat_lock);
+
+static DEFINE_MUTEX(nf_nat_proto_mutex);
+static const struct nf_nat_l3proto __rcu *nf_nat_l3protos[NFPROTO_NUMPROTO]
+ __read_mostly;
+static const struct nf_nat_l4proto __rcu **nf_nat_l4protos[NFPROTO_NUMPROTO]
+ __read_mostly;
+
+
+inline const struct nf_nat_l3proto *
+__nf_nat_l3proto_find(u8 family)
+{
+ return rcu_dereference(nf_nat_l3protos[family]);
+}
+
+inline const struct nf_nat_l4proto *
+__nf_nat_l4proto_find(u8 family, u8 protonum)
+{
+ return rcu_dereference(nf_nat_l4protos[family][protonum]);
+}
+EXPORT_SYMBOL_GPL(__nf_nat_l4proto_find);
+
+#ifdef CONFIG_XFRM
+static void __nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl)
+{
+ const struct nf_nat_l3proto *l3proto;
+ const struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ enum ip_conntrack_dir dir;
+ unsigned long statusbit;
+ u8 family;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ if (ct == NULL)
+ return;
+
+ family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
+ rcu_read_lock();
+ l3proto = __nf_nat_l3proto_find(family);
+ if (l3proto == NULL)
+ goto out;
+
+ dir = CTINFO2DIR(ctinfo);
+ if (dir == IP_CT_DIR_ORIGINAL)
+ statusbit = IPS_DST_NAT;
+ else
+ statusbit = IPS_SRC_NAT;
+
+ l3proto->decode_session(skb, ct, dir, statusbit, fl);
+out:
+ rcu_read_unlock();
+}
+
+int nf_xfrm_me_harder(struct sk_buff *skb, unsigned int family)
+{
+ struct flowi fl;
+ unsigned int hh_len;
+ struct dst_entry *dst;
+ int err;
+
+ err = xfrm_decode_session(skb, &fl, family);
+ if (err < 0)
+ return err;
+
+ dst = skb_dst(skb);
+ if (dst->xfrm)
+ dst = ((struct xfrm_dst *)dst)->route;
+ dst_hold(dst);
+
+ dst = xfrm_lookup(dev_net(dst->dev), dst, &fl, skb->sk, 0);
+ if (IS_ERR(dst))
+ return PTR_ERR(dst);
+
+ skb_dst_drop(skb);
+ skb_dst_set(skb, dst);
+
+ /* Change in oif may mean change in hh_len. */
+ hh_len = skb_dst(skb)->dev->hard_header_len;
+ if (skb_headroom(skb) < hh_len &&
+ pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC))
+ return -ENOMEM;
+ return 0;
+}
+EXPORT_SYMBOL(nf_xfrm_me_harder);
+#endif /* CONFIG_XFRM */
+
+/* We keep an extra hash for each conntrack, for fast searching. */
+static inline unsigned int
+hash_by_src(const struct net *net, u16 zone,
+ const struct nf_conntrack_tuple *tuple)
+{
+ unsigned int hash;
+
+ /* Original src, to ensure we map it consistently if poss. */
+ hash = jhash2((u32 *)&tuple->src, sizeof(tuple->src) / sizeof(u32),
+ tuple->dst.protonum ^ zone ^ nf_conntrack_hash_rnd);
+
+ return reciprocal_scale(hash, net->ct.nat_htable_size);
+}
+
+/* Is this tuple already taken? (not by us) */
+int
+nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
+ const struct nf_conn *ignored_conntrack)
+{
+ /* Conntrack tracking doesn't keep track of outgoing tuples; only
+ * incoming ones. NAT means they don't have a fixed mapping,
+ * so we invert the tuple and look for the incoming reply.
+ *
+ * We could keep a separate hash if this proves too slow.
+ */
+ struct nf_conntrack_tuple reply;
+
+ nf_ct_invert_tuplepr(&reply, tuple);
+ return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
+}
+EXPORT_SYMBOL(nf_nat_used_tuple);
+
+/* If we source map this tuple so reply looks like reply_tuple, will
+ * that meet the constraints of range.
+ */
+static int in_range(const struct nf_nat_l3proto *l3proto,
+ const struct nf_nat_l4proto *l4proto,
+ const struct nf_conntrack_tuple *tuple,
+ const struct nf_nat_range *range)
+{
+ /* If we are supposed to map IPs, then we must be in the
+ * range specified, otherwise let this drag us onto a new src IP.
+ */
+ if (range->flags & NF_NAT_RANGE_MAP_IPS &&
+ !l3proto->in_range(tuple, range))
+ return 0;
+
+ if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) ||
+ l4proto->in_range(tuple, NF_NAT_MANIP_SRC,
+ &range->min_proto, &range->max_proto))
+ return 1;
+
+ return 0;
+}
+
+static inline int
+same_src(const struct nf_conn *ct,
+ const struct nf_conntrack_tuple *tuple)
+{
+ const struct nf_conntrack_tuple *t;
+
+ t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
+ return (t->dst.protonum == tuple->dst.protonum &&
+ nf_inet_addr_cmp(&t->src.u3, &tuple->src.u3) &&
+ t->src.u.all == tuple->src.u.all);
+}
+
+/* Only called for SRC manip */
+static int
+find_appropriate_src(struct net *net, u16 zone,
+ const struct nf_nat_l3proto *l3proto,
+ const struct nf_nat_l4proto *l4proto,
+ const struct nf_conntrack_tuple *tuple,
+ struct nf_conntrack_tuple *result,
+ const struct nf_nat_range *range)
+{
+ unsigned int h = hash_by_src(net, zone, tuple);
+ const struct nf_conn_nat *nat;
+ const struct nf_conn *ct;
+
+ hlist_for_each_entry_rcu(nat, &net->ct.nat_bysource[h], bysource) {
+ ct = nat->ct;
+ if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) {
+ /* Copy source part from reply tuple. */
+ nf_ct_invert_tuplepr(result,
+ &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+ result->dst = tuple->dst;
+
+ if (in_range(l3proto, l4proto, result, range))
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/* For [FUTURE] fragmentation handling, we want the least-used
+ * src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus
+ * if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
+ * 1-65535, we don't do pro-rata allocation based on ports; we choose
+ * the ip with the lowest src-ip/dst-ip/proto usage.
+ */
+static void
+find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple,
+ const struct nf_nat_range *range,
+ const struct nf_conn *ct,
+ enum nf_nat_manip_type maniptype)
+{
+ union nf_inet_addr *var_ipp;
+ unsigned int i, max;
+ /* Host order */
+ u32 minip, maxip, j, dist;
+ bool full_range;
+
+ /* No IP mapping? Do nothing. */
+ if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
+ return;
+
+ if (maniptype == NF_NAT_MANIP_SRC)
+ var_ipp = &tuple->src.u3;
+ else
+ var_ipp = &tuple->dst.u3;
+
+ /* Fast path: only one choice. */
+ if (nf_inet_addr_cmp(&range->min_addr, &range->max_addr)) {
+ *var_ipp = range->min_addr;
+ return;
+ }
+
+ if (nf_ct_l3num(ct) == NFPROTO_IPV4)
+ max = sizeof(var_ipp->ip) / sizeof(u32) - 1;
+ else
+ max = sizeof(var_ipp->ip6) / sizeof(u32) - 1;
+
+ /* Hashing source and destination IPs gives a fairly even
+ * spread in practice (if there are a small number of IPs
+ * involved, there usually aren't that many connections
+ * anyway). The consistency means that servers see the same
+ * client coming from the same IP (some Internet Banking sites
+ * like this), even across reboots.
+ */
+ j = jhash2((u32 *)&tuple->src.u3, sizeof(tuple->src.u3) / sizeof(u32),
+ range->flags & NF_NAT_RANGE_PERSISTENT ?
+ 0 : (__force u32)tuple->dst.u3.all[max] ^ zone);
+
+ full_range = false;
+ for (i = 0; i <= max; i++) {
+ /* If first bytes of the address are at the maximum, use the
+ * distance. Otherwise use the full range.
+ */
+ if (!full_range) {
+ minip = ntohl((__force __be32)range->min_addr.all[i]);
+ maxip = ntohl((__force __be32)range->max_addr.all[i]);
+ dist = maxip - minip + 1;
+ } else {
+ minip = 0;
+ dist = ~0;
+ }
+
+ var_ipp->all[i] = (__force __u32)
+ htonl(minip + reciprocal_scale(j, dist));
+ if (var_ipp->all[i] != range->max_addr.all[i])
+ full_range = true;
+
+ if (!(range->flags & NF_NAT_RANGE_PERSISTENT))
+ j ^= (__force u32)tuple->dst.u3.all[i];
+ }
+}
+
+/* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
+ * we change the source to map into the range. For NF_INET_PRE_ROUTING
+ * and NF_INET_LOCAL_OUT, we change the destination to map into the
+ * range. It might not be possible to get a unique tuple, but we try.
+ * At worst (or if we race), we will end up with a final duplicate in
+ * __ip_conntrack_confirm and drop the packet. */
+static void
+get_unique_tuple(struct nf_conntrack_tuple *tuple,
+ const struct nf_conntrack_tuple *orig_tuple,
+ const struct nf_nat_range *range,
+ struct nf_conn *ct,
+ enum nf_nat_manip_type maniptype)
+{
+ const struct nf_nat_l3proto *l3proto;
+ const struct nf_nat_l4proto *l4proto;
+ struct net *net = nf_ct_net(ct);
+ u16 zone = nf_ct_zone(ct);
+
+ rcu_read_lock();
+ l3proto = __nf_nat_l3proto_find(orig_tuple->src.l3num);
+ l4proto = __nf_nat_l4proto_find(orig_tuple->src.l3num,
+ orig_tuple->dst.protonum);
+
+ /* 1) If this srcip/proto/src-proto-part is currently mapped,
+ * and that same mapping gives a unique tuple within the given
+ * range, use that.
+ *
+ * This is only required for source (ie. NAT/masq) mappings.
+ * So far, we don't do local source mappings, so multiple
+ * manips not an issue.
+ */
+ if (maniptype == NF_NAT_MANIP_SRC &&
+ !(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
+ /* try the original tuple first */
+ if (in_range(l3proto, l4proto, orig_tuple, range)) {
+ if (!nf_nat_used_tuple(orig_tuple, ct)) {
+ *tuple = *orig_tuple;
+ goto out;
+ }
+ } else if (find_appropriate_src(net, zone, l3proto, l4proto,
+ orig_tuple, tuple, range)) {
+ pr_debug("get_unique_tuple: Found current src map\n");
+ if (!nf_nat_used_tuple(tuple, ct))
+ goto out;
+ }
+ }
+
+ /* 2) Select the least-used IP/proto combination in the given range */
+ *tuple = *orig_tuple;
+ find_best_ips_proto(zone, tuple, range, ct, maniptype);
+
+ /* 3) The per-protocol part of the manip is made to map into
+ * the range to make a unique tuple.
+ */
+
+ /* Only bother mapping if it's not already in range and unique */
+ if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
+ if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
+ if (l4proto->in_range(tuple, maniptype,
+ &range->min_proto,
+ &range->max_proto) &&
+ (range->min_proto.all == range->max_proto.all ||
+ !nf_nat_used_tuple(tuple, ct)))
+ goto out;
+ } else if (!nf_nat_used_tuple(tuple, ct)) {
+ goto out;
+ }
+ }
+
+ /* Last change: get protocol to try to obtain unique tuple. */
+ l4proto->unique_tuple(l3proto, tuple, range, maniptype, ct);
+out:
+ rcu_read_unlock();
+}
+
+struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct)
+{
+ struct nf_conn_nat *nat = nfct_nat(ct);
+ if (nat)
+ return nat;
+
+ if (!nf_ct_is_confirmed(ct))
+ nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
+
+ return nat;
+}
+EXPORT_SYMBOL_GPL(nf_ct_nat_ext_add);
+
+unsigned int
+nf_nat_setup_info(struct nf_conn *ct,
+ const struct nf_nat_range *range,
+ enum nf_nat_manip_type maniptype)
+{
+ struct net *net = nf_ct_net(ct);
+ struct nf_conntrack_tuple curr_tuple, new_tuple;
+ struct nf_conn_nat *nat;
+
+ /* nat helper or nfctnetlink also setup binding */
+ nat = nf_ct_nat_ext_add(ct);
+ if (nat == NULL)
+ return NF_ACCEPT;
+
+ NF_CT_ASSERT(maniptype == NF_NAT_MANIP_SRC ||
+ maniptype == NF_NAT_MANIP_DST);
+ BUG_ON(nf_nat_initialized(ct, maniptype));
+
+ /* What we've got will look like inverse of reply. Normally
+ * this is what is in the conntrack, except for prior
+ * manipulations (future optimization: if num_manips == 0,
+ * orig_tp = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
+ */
+ nf_ct_invert_tuplepr(&curr_tuple,
+ &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+
+ get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
+
+ if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
+ struct nf_conntrack_tuple reply;
+
+ /* Alter conntrack table so will recognize replies. */
+ nf_ct_invert_tuplepr(&reply, &new_tuple);
+ nf_conntrack_alter_reply(ct, &reply);
+
+ /* Non-atomic: we own this at the moment. */
+ if (maniptype == NF_NAT_MANIP_SRC)
+ ct->status |= IPS_SRC_NAT;
+ else
+ ct->status |= IPS_DST_NAT;
+
+ if (nfct_help(ct))
+ nfct_seqadj_ext_add(ct);
+ }
+
+ if (maniptype == NF_NAT_MANIP_SRC) {
+ unsigned int srchash;
+
+ srchash = hash_by_src(net, nf_ct_zone(ct),
+ &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+ spin_lock_bh(&nf_nat_lock);
+ /* nf_conntrack_alter_reply might re-allocate extension aera */
+ nat = nfct_nat(ct);
+ nat->ct = ct;
+ hlist_add_head_rcu(&nat->bysource,
+ &net->ct.nat_bysource[srchash]);
+ spin_unlock_bh(&nf_nat_lock);
+ }
+
+ /* It's done. */
+ if (maniptype == NF_NAT_MANIP_DST)
+ ct->status |= IPS_DST_NAT_DONE;
+ else
+ ct->status |= IPS_SRC_NAT_DONE;
+
+ return NF_ACCEPT;
+}
+EXPORT_SYMBOL(nf_nat_setup_info);
+
+static unsigned int
+__nf_nat_alloc_null_binding(struct nf_conn *ct, enum nf_nat_manip_type manip)
+{
+ /* Force range to this IP; let proto decide mapping for
+ * per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
+ * Use reply in case it's already been mangled (eg local packet).
+ */
+ union nf_inet_addr ip =
+ (manip == NF_NAT_MANIP_SRC ?
+ ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3 :
+ ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3);
+ struct nf_nat_range range = {
+ .flags = NF_NAT_RANGE_MAP_IPS,
+ .min_addr = ip,
+ .max_addr = ip,
+ };
+ return nf_nat_setup_info(ct, &range, manip);
+}
+
+unsigned int
+nf_nat_alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
+{
+ return __nf_nat_alloc_null_binding(ct, HOOK2MANIP(hooknum));
+}
+EXPORT_SYMBOL_GPL(nf_nat_alloc_null_binding);
+
+/* Do packet manipulations according to nf_nat_setup_info. */
+unsigned int nf_nat_packet(struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ unsigned int hooknum,
+ struct sk_buff *skb)
+{
+ const struct nf_nat_l3proto *l3proto;
+ const struct nf_nat_l4proto *l4proto;
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ unsigned long statusbit;
+ enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
+
+ if (mtype == NF_NAT_MANIP_SRC)
+ statusbit = IPS_SRC_NAT;
+ else
+ statusbit = IPS_DST_NAT;
+
+ /* Invert if this is reply dir. */
+ if (dir == IP_CT_DIR_REPLY)
+ statusbit ^= IPS_NAT_MASK;
+
+ /* Non-atomic: these bits don't change. */
+ if (ct->status & statusbit) {
+ struct nf_conntrack_tuple target;
+
+ /* We are aiming to look like inverse of other direction. */
+ nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
+
+ l3proto = __nf_nat_l3proto_find(target.src.l3num);
+ l4proto = __nf_nat_l4proto_find(target.src.l3num,
+ target.dst.protonum);
+ if (!l3proto->manip_pkt(skb, 0, l4proto, &target, mtype))
+ return NF_DROP;
+ }
+ return NF_ACCEPT;
+}
+EXPORT_SYMBOL_GPL(nf_nat_packet);
+
+struct nf_nat_proto_clean {
+ u8 l3proto;
+ u8 l4proto;
+};
+
+/* kill conntracks with affected NAT section */
+static int nf_nat_proto_remove(struct nf_conn *i, void *data)
+{
+ const struct nf_nat_proto_clean *clean = data;
+ struct nf_conn_nat *nat = nfct_nat(i);
+
+ if (!nat)
+ return 0;
+
+ if ((clean->l3proto && nf_ct_l3num(i) != clean->l3proto) ||
+ (clean->l4proto && nf_ct_protonum(i) != clean->l4proto))
+ return 0;
+
+ return i->status & IPS_NAT_MASK ? 1 : 0;
+}
+
+static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
+{
+ struct nf_conn_nat *nat = nfct_nat(ct);
+
+ if (nf_nat_proto_remove(ct, data))
+ return 1;
+
+ if (!nat || !nat->ct)
+ return 0;
+
+ /* This netns is being destroyed, and conntrack has nat null binding.
+ * Remove it from bysource hash, as the table will be freed soon.
+ *
+ * Else, when the conntrack is destoyed, nf_nat_cleanup_conntrack()
+ * will delete entry from already-freed table.
+ */
+ if (!del_timer(&ct->timeout))
+ return 1;
+
+ spin_lock_bh(&nf_nat_lock);
+ hlist_del_rcu(&nat->bysource);
+ ct->status &= ~IPS_NAT_DONE_MASK;
+ nat->ct = NULL;
+ spin_unlock_bh(&nf_nat_lock);
+
+ add_timer(&ct->timeout);
+
+ /* don't delete conntrack. Although that would make things a lot
+ * simpler, we'd end up flushing all conntracks on nat rmmod.
+ */
+ return 0;
+}
+
+static void nf_nat_l4proto_clean(u8 l3proto, u8 l4proto)
+{
+ struct nf_nat_proto_clean clean = {
+ .l3proto = l3proto,
+ .l4proto = l4proto,
+ };
+ struct net *net;
+
+ rtnl_lock();
+ for_each_net(net)
+ nf_ct_iterate_cleanup(net, nf_nat_proto_remove, &clean, 0, 0);
+ rtnl_unlock();
+}
+
+static void nf_nat_l3proto_clean(u8 l3proto)
+{
+ struct nf_nat_proto_clean clean = {
+ .l3proto = l3proto,
+ };
+ struct net *net;
+
+ rtnl_lock();
+
+ for_each_net(net)
+ nf_ct_iterate_cleanup(net, nf_nat_proto_remove, &clean, 0, 0);
+ rtnl_unlock();
+}
+
+/* Protocol registration. */
+int nf_nat_l4proto_register(u8 l3proto, const struct nf_nat_l4proto *l4proto)
+{
+ const struct nf_nat_l4proto **l4protos;
+ unsigned int i;
+ int ret = 0;
+
+ mutex_lock(&nf_nat_proto_mutex);
+ if (nf_nat_l4protos[l3proto] == NULL) {
+ l4protos = kmalloc(IPPROTO_MAX * sizeof(struct nf_nat_l4proto *),
+ GFP_KERNEL);
+ if (l4protos == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ for (i = 0; i < IPPROTO_MAX; i++)
+ RCU_INIT_POINTER(l4protos[i], &nf_nat_l4proto_unknown);
+
+ /* Before making proto_array visible to lockless readers,
+ * we must make sure its content is committed to memory.
+ */
+ smp_wmb();
+
+ nf_nat_l4protos[l3proto] = l4protos;
+ }
+
+ if (rcu_dereference_protected(
+ nf_nat_l4protos[l3proto][l4proto->l4proto],
+ lockdep_is_held(&nf_nat_proto_mutex)
+ ) != &nf_nat_l4proto_unknown) {
+ ret = -EBUSY;
+ goto out;
+ }
+ RCU_INIT_POINTER(nf_nat_l4protos[l3proto][l4proto->l4proto], l4proto);
+ out:
+ mutex_unlock(&nf_nat_proto_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_register);
+
+/* No one stores the protocol anywhere; simply delete it. */
+void nf_nat_l4proto_unregister(u8 l3proto, const struct nf_nat_l4proto *l4proto)
+{
+ mutex_lock(&nf_nat_proto_mutex);
+ RCU_INIT_POINTER(nf_nat_l4protos[l3proto][l4proto->l4proto],
+ &nf_nat_l4proto_unknown);
+ mutex_unlock(&nf_nat_proto_mutex);
+ synchronize_rcu();
+
+ nf_nat_l4proto_clean(l3proto, l4proto->l4proto);
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_unregister);
+
+int nf_nat_l3proto_register(const struct nf_nat_l3proto *l3proto)
+{
+ int err;
+
+ err = nf_ct_l3proto_try_module_get(l3proto->l3proto);
+ if (err < 0)
+ return err;
+
+ mutex_lock(&nf_nat_proto_mutex);
+ RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_TCP],
+ &nf_nat_l4proto_tcp);
+ RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_UDP],
+ &nf_nat_l4proto_udp);
+ mutex_unlock(&nf_nat_proto_mutex);
+
+ RCU_INIT_POINTER(nf_nat_l3protos[l3proto->l3proto], l3proto);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nf_nat_l3proto_register);
+
+void nf_nat_l3proto_unregister(const struct nf_nat_l3proto *l3proto)
+{
+ mutex_lock(&nf_nat_proto_mutex);
+ RCU_INIT_POINTER(nf_nat_l3protos[l3proto->l3proto], NULL);
+ mutex_unlock(&nf_nat_proto_mutex);
+ synchronize_rcu();
+
+ nf_nat_l3proto_clean(l3proto->l3proto);
+ nf_ct_l3proto_module_put(l3proto->l3proto);
+}
+EXPORT_SYMBOL_GPL(nf_nat_l3proto_unregister);
+
+/* No one using conntrack by the time this called. */
+static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
+{
+ struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
+
+ if (nat == NULL || nat->ct == NULL)
+ return;
+
+ NF_CT_ASSERT(nat->ct->status & IPS_SRC_NAT_DONE);
+
+ spin_lock_bh(&nf_nat_lock);
+ hlist_del_rcu(&nat->bysource);
+ spin_unlock_bh(&nf_nat_lock);
+}
+
+static void nf_nat_move_storage(void *new, void *old)
+{
+ struct nf_conn_nat *new_nat = new;
+ struct nf_conn_nat *old_nat = old;
+ struct nf_conn *ct = old_nat->ct;
+
+ if (!ct || !(ct->status & IPS_SRC_NAT_DONE))
+ return;
+
+ spin_lock_bh(&nf_nat_lock);
+ hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
+ spin_unlock_bh(&nf_nat_lock);
+}
+
+static struct nf_ct_ext_type nat_extend __read_mostly = {
+ .len = sizeof(struct nf_conn_nat),
+ .align = __alignof__(struct nf_conn_nat),
+ .destroy = nf_nat_cleanup_conntrack,
+ .move = nf_nat_move_storage,
+ .id = NF_CT_EXT_NAT,
+ .flags = NF_CT_EXT_F_PREALLOC,
+};
+
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
+ [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
+ [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
+};
+
+static int nfnetlink_parse_nat_proto(struct nlattr *attr,
+ const struct nf_conn *ct,
+ struct nf_nat_range *range)
+{
+ struct nlattr *tb[CTA_PROTONAT_MAX+1];
+ const struct nf_nat_l4proto *l4proto;
+ int err;
+
+ err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
+ if (err < 0)
+ return err;
+
+ l4proto = __nf_nat_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
+ if (l4proto->nlattr_to_range)
+ err = l4proto->nlattr_to_range(tb, range);
+
+ return err;
+}
+
+static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
+ [CTA_NAT_V4_MINIP] = { .type = NLA_U32 },
+ [CTA_NAT_V4_MAXIP] = { .type = NLA_U32 },
+ [CTA_NAT_V6_MINIP] = { .len = sizeof(struct in6_addr) },
+ [CTA_NAT_V6_MAXIP] = { .len = sizeof(struct in6_addr) },
+ [CTA_NAT_PROTO] = { .type = NLA_NESTED },
+};
+
+static int
+nfnetlink_parse_nat(const struct nlattr *nat,
+ const struct nf_conn *ct, struct nf_nat_range *range,
+ const struct nf_nat_l3proto *l3proto)
+{
+ struct nlattr *tb[CTA_NAT_MAX+1];
+ int err;
+
+ memset(range, 0, sizeof(*range));
+
+ err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
+ if (err < 0)
+ return err;
+
+ err = l3proto->nlattr_to_range(tb, range);
+ if (err < 0)
+ return err;
+
+ if (!tb[CTA_NAT_PROTO])
+ return 0;
+
+ return nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
+}
+
+/* This function is called under rcu_read_lock() */
+static int
+nfnetlink_parse_nat_setup(struct nf_conn *ct,
+ enum nf_nat_manip_type manip,
+ const struct nlattr *attr)
+{
+ struct nf_nat_range range;
+ const struct nf_nat_l3proto *l3proto;
+ int err;
+
+ /* Should not happen, restricted to creating new conntracks
+ * via ctnetlink.
+ */
+ if (WARN_ON_ONCE(nf_nat_initialized(ct, manip)))
+ return -EEXIST;
+
+ /* Make sure that L3 NAT is there by when we call nf_nat_setup_info to
+ * attach the null binding, otherwise this may oops.
+ */
+ l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct));
+ if (l3proto == NULL)
+ return -EAGAIN;
+
+ /* No NAT information has been passed, allocate the null-binding */
+ if (attr == NULL)
+ return __nf_nat_alloc_null_binding(ct, manip);
+
+ err = nfnetlink_parse_nat(attr, ct, &range, l3proto);
+ if (err < 0)
+ return err;
+
+ return nf_nat_setup_info(ct, &range, manip);
+}
+#else
+static int
+nfnetlink_parse_nat_setup(struct nf_conn *ct,
+ enum nf_nat_manip_type manip,
+ const struct nlattr *attr)
+{
+ return -EOPNOTSUPP;
+}
+#endif
+
+static int __net_init nf_nat_net_init(struct net *net)
+{
+ /* Leave them the same for the moment. */
+ net->ct.nat_htable_size = net->ct.htable_size;
+ net->ct.nat_bysource = nf_ct_alloc_hashtable(&net->ct.nat_htable_size, 0);
+ if (!net->ct.nat_bysource)
+ return -ENOMEM;
+ return 0;
+}
+
+static void __net_exit nf_nat_net_exit(struct net *net)
+{
+ struct nf_nat_proto_clean clean = {};
+
+ nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean, 0, 0);
+ synchronize_rcu();
+ nf_ct_free_hashtable(net->ct.nat_bysource, net->ct.nat_htable_size);
+}
+
+static struct pernet_operations nf_nat_net_ops = {
+ .init = nf_nat_net_init,
+ .exit = nf_nat_net_exit,
+};
+
+static struct nf_ct_helper_expectfn follow_master_nat = {
+ .name = "nat-follow-master",
+ .expectfn = nf_nat_follow_master,
+};
+
+static int __init nf_nat_init(void)
+{
+ int ret;
+
+ ret = nf_ct_extend_register(&nat_extend);
+ if (ret < 0) {
+ printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
+ return ret;
+ }
+
+ ret = register_pernet_subsys(&nf_nat_net_ops);
+ if (ret < 0)
+ goto cleanup_extend;
+
+ nf_ct_helper_expectfn_register(&follow_master_nat);
+
+ /* Initialize fake conntrack so that NAT will skip it */
+ nf_ct_untracked_status_or(IPS_NAT_DONE_MASK);
+
+ BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
+ RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook,
+ nfnetlink_parse_nat_setup);
+#ifdef CONFIG_XFRM
+ BUG_ON(nf_nat_decode_session_hook != NULL);
+ RCU_INIT_POINTER(nf_nat_decode_session_hook, __nf_nat_decode_session);
+#endif
+ return 0;
+
+ cleanup_extend:
+ nf_ct_extend_unregister(&nat_extend);
+ return ret;
+}
+
+static void __exit nf_nat_cleanup(void)
+{
+ unsigned int i;
+
+ unregister_pernet_subsys(&nf_nat_net_ops);
+ nf_ct_extend_unregister(&nat_extend);
+ nf_ct_helper_expectfn_unregister(&follow_master_nat);
+ RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL);
+#ifdef CONFIG_XFRM
+ RCU_INIT_POINTER(nf_nat_decode_session_hook, NULL);
+#endif
+ for (i = 0; i < NFPROTO_NUMPROTO; i++)
+ kfree(nf_nat_l4protos[i]);
+ synchronize_net();
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(nf_nat_init);
+module_exit(nf_nat_cleanup);
Code Review / kvmfornfv.git / blobdiff