diff options
author | Patrick McHardy <kaber@trash.net> | 2012-08-26 19:14:06 +0200 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2012-08-30 03:00:14 +0200 |
commit | c7232c9979cba684c50b64c513c4a83c9aa70563 (patch) | |
tree | dbe0fdac62191d85935f5a3dfe815c1b1add60f9 /net/netfilter/nf_nat_core.c | |
parent | 051966c0c644a1c96092d4206e00704ade813c9a (diff) | |
download | op-kernel-dev-c7232c9979cba684c50b64c513c4a83c9aa70563.zip op-kernel-dev-c7232c9979cba684c50b64c513c4a83c9aa70563.tar.gz |
netfilter: add protocol independent NAT core
Convert the IPv4 NAT implementation to a protocol independent core and
address family specific modules.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/netfilter/nf_nat_core.c')
-rw-r--r-- | net/netfilter/nf_nat_core.c | 854 |
1 files changed, 854 insertions, 0 deletions
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c new file mode 100644 index 0000000..c577b75 --- /dev/null +++ b/net/netfilter/nf_nat_core.c @@ -0,0 +1,854 @@ +/* + * (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_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; + + if (xfrm_decode_session(skb, &fl, family) < 0) + return -1; + + 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 -1; + + 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 -1; + 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 ((u64)hash * net->ct.nat_htable_size) >> 32; +} + +/* 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; + const struct hlist_node *n; + + hlist_for_each_entry_rcu(nat, n, &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)) { + rcu_read_unlock(); + 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), + 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 + (((u64)j * dist) >> 32)); + 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)) { + /* 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)) { + 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(); +} + +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 = nfct_nat(ct); + if (!nat) { + nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); + if (nat == NULL) { + pr_debug("failed to add NAT extension\n"); + 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 (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); + +/* 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; + bool hash; +}; + +/* Clear NAT section of all conntracks, in case we're loaded again. */ +static int nf_nat_proto_clean(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; + + if (clean->hash) { + spin_lock_bh(&nf_nat_lock); + hlist_del_rcu(&nat->bysource); + spin_unlock_bh(&nf_nat_lock); + } else { + memset(nat, 0, sizeof(*nat)); + i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | + IPS_SEQ_ADJUST); + } + 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(); + /* Step 1 - remove from bysource hash */ + clean.hash = true; + for_each_net(net) + nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean); + synchronize_rcu(); + + /* Step 2 - clean NAT section */ + clean.hash = false; + for_each_net(net) + nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean); + rtnl_unlock(); +} + +static void nf_nat_l3proto_clean(u8 l3proto) +{ + struct nf_nat_proto_clean clean = { + .l3proto = l3proto, + }; + struct net *net; + + rtnl_lock(); + /* Step 1 - remove from bysource hash */ + clean.hash = true; + for_each_net(net) + nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean); + synchronize_rcu(); + + /* Step 2 - clean NAT section */ + clean.hash = false; + for_each_net(net) + nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean); + 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 defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) + +#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_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; + + rcu_read_lock(); + l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct)); + if (l3proto == NULL) { + err = -EAGAIN; + goto out; + } + err = l3proto->nlattr_to_range(tb, range); + if (err < 0) + goto out; + + if (!tb[CTA_NAT_PROTO]) + goto out; + + err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range); +out: + rcu_read_unlock(); + return err; +} + +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; + int err; + + err = nfnetlink_parse_nat(attr, ct, &range); + if (err < 0) + return err; + if (nf_nat_initialized(ct, manip)) + return -EEXIST; + + 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); + 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 struct nfq_ct_nat_hook nfq_ct_nat = { + .seq_adjust = nf_nat_tcp_seq_adjust, +}; + +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(nf_nat_seq_adjust_hook != NULL); + RCU_INIT_POINTER(nf_nat_seq_adjust_hook, nf_nat_seq_adjust); + BUG_ON(nfnetlink_parse_nat_setup_hook != NULL); + RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, + nfnetlink_parse_nat_setup); + BUG_ON(nf_ct_nat_offset != NULL); + RCU_INIT_POINTER(nf_ct_nat_offset, nf_nat_get_offset); + RCU_INIT_POINTER(nfq_ct_nat_hook, &nfq_ct_nat); +#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(nf_nat_seq_adjust_hook, NULL); + RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL); + RCU_INIT_POINTER(nf_ct_nat_offset, NULL); + RCU_INIT_POINTER(nfq_ct_nat_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); |