diff options
Diffstat (limited to 'net/netfilter/nf_nat_core.c')
-rw-r--r-- | net/netfilter/nf_nat_core.c | 321 |
1 files changed, 283 insertions, 38 deletions
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 617693ff9f4c..b7df32a56e7e 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -32,6 +32,8 @@ #include <net/netfilter/nf_conntrack_zones.h> #include <linux/netfilter/nf_nat.h> +#include "nf_internals.h" + static spinlock_t nf_nat_locks[CONNTRACK_LOCKS]; static DEFINE_MUTEX(nf_nat_proto_mutex); @@ -39,11 +41,27 @@ 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; +static unsigned int nat_net_id __read_mostly; static struct hlist_head *nf_nat_bysource __read_mostly; static unsigned int nf_nat_htable_size __read_mostly; static unsigned int nf_nat_hash_rnd __read_mostly; +struct nf_nat_lookup_hook_priv { + struct nf_hook_entries __rcu *entries; + + struct rcu_head rcu_head; +}; + +struct nf_nat_hooks_net { + struct nf_hook_ops *nat_hook_ops; + unsigned int users; +}; + +struct nat_net { + struct nf_nat_hooks_net nat_proto_net[NFPROTO_NUMPROTO]; +}; + inline const struct nf_nat_l3proto * __nf_nat_l3proto_find(u8 family) { @@ -157,7 +175,7 @@ EXPORT_SYMBOL(nf_nat_used_tuple); 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) + const struct nf_nat_range2 *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. @@ -194,7 +212,7 @@ find_appropriate_src(struct net *net, const struct nf_nat_l4proto *l4proto, const struct nf_conntrack_tuple *tuple, struct nf_conntrack_tuple *result, - const struct nf_nat_range *range) + const struct nf_nat_range2 *range) { unsigned int h = hash_by_src(net, tuple); const struct nf_conn *ct; @@ -224,7 +242,7 @@ find_appropriate_src(struct net *net, static void find_best_ips_proto(const struct nf_conntrack_zone *zone, struct nf_conntrack_tuple *tuple, - const struct nf_nat_range *range, + const struct nf_nat_range2 *range, const struct nf_conn *ct, enum nf_nat_manip_type maniptype) { @@ -298,7 +316,7 @@ find_best_ips_proto(const struct nf_conntrack_zone *zone, static void get_unique_tuple(struct nf_conntrack_tuple *tuple, const struct nf_conntrack_tuple *orig_tuple, - const struct nf_nat_range *range, + const struct nf_nat_range2 *range, struct nf_conn *ct, enum nf_nat_manip_type maniptype) { @@ -349,9 +367,10 @@ get_unique_tuple(struct nf_conntrack_tuple *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) && + if (!(range->flags & NF_NAT_RANGE_PROTO_OFFSET) && + 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; @@ -360,7 +379,7 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple, } } - /* Last change: get protocol to try to obtain unique tuple. */ + /* Last chance: get protocol to try to obtain unique tuple. */ l4proto->unique_tuple(l3proto, tuple, range, maniptype, ct); out: rcu_read_unlock(); @@ -381,7 +400,7 @@ EXPORT_SYMBOL_GPL(nf_ct_nat_ext_add); unsigned int nf_nat_setup_info(struct nf_conn *ct, - const struct nf_nat_range *range, + const struct nf_nat_range2 *range, enum nf_nat_manip_type maniptype) { struct net *net = nf_ct_net(ct); @@ -459,7 +478,7 @@ __nf_nat_alloc_null_binding(struct nf_conn *ct, enum nf_nat_manip_type manip) (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 = { + struct nf_nat_range2 range = { .flags = NF_NAT_RANGE_MAP_IPS, .min_addr = ip, .max_addr = ip, @@ -474,17 +493,36 @@ nf_nat_alloc_null_binding(struct nf_conn *ct, unsigned int hooknum) } EXPORT_SYMBOL_GPL(nf_nat_alloc_null_binding); +static unsigned int nf_nat_manip_pkt(struct sk_buff *skb, struct nf_conn *ct, + enum nf_nat_manip_type mtype, + enum ip_conntrack_dir dir) +{ + const struct nf_nat_l3proto *l3proto; + const struct nf_nat_l4proto *l4proto; + 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; +} + /* 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 nf_nat_manip_type mtype = HOOK2MANIP(hooknum); enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); + unsigned int verdict = NF_ACCEPT; unsigned long statusbit; - enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum); if (mtype == NF_NAT_MANIP_SRC) statusbit = IPS_SRC_NAT; @@ -496,21 +534,87 @@ unsigned int nf_nat_packet(struct nf_conn *ct, statusbit ^= IPS_NAT_MASK; /* Non-atomic: these bits don't change. */ - if (ct->status & statusbit) { - struct nf_conntrack_tuple target; + if (ct->status & statusbit) + verdict = nf_nat_manip_pkt(skb, ct, mtype, dir); + + return verdict; +} +EXPORT_SYMBOL_GPL(nf_nat_packet); + +unsigned int +nf_nat_inet_fn(void *priv, struct sk_buff *skb, + const struct nf_hook_state *state) +{ + struct nf_conn *ct; + enum ip_conntrack_info ctinfo; + struct nf_conn_nat *nat; + /* maniptype == SRC for postrouting. */ + enum nf_nat_manip_type maniptype = HOOK2MANIP(state->hook); + + ct = nf_ct_get(skb, &ctinfo); + /* Can't track? It's not due to stress, or conntrack would + * have dropped it. Hence it's the user's responsibilty to + * packet filter it out, or implement conntrack/NAT for that + * protocol. 8) --RR + */ + if (!ct) + return NF_ACCEPT; - /* We are aiming to look like inverse of other direction. */ - nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); + nat = nfct_nat(ct); - 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; + switch (ctinfo) { + case IP_CT_RELATED: + case IP_CT_RELATED_REPLY: + /* Only ICMPs can be IP_CT_IS_REPLY. Fallthrough */ + case IP_CT_NEW: + /* Seen it before? This can happen for loopback, retrans, + * or local packets. + */ + if (!nf_nat_initialized(ct, maniptype)) { + struct nf_nat_lookup_hook_priv *lpriv = priv; + struct nf_hook_entries *e = rcu_dereference(lpriv->entries); + unsigned int ret; + int i; + + if (!e) + goto null_bind; + + for (i = 0; i < e->num_hook_entries; i++) { + ret = e->hooks[i].hook(e->hooks[i].priv, skb, + state); + if (ret != NF_ACCEPT) + return ret; + if (nf_nat_initialized(ct, maniptype)) + goto do_nat; + } +null_bind: + ret = nf_nat_alloc_null_binding(ct, state->hook); + if (ret != NF_ACCEPT) + return ret; + } else { + pr_debug("Already setup manip %s for ct %p (status bits 0x%lx)\n", + maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST", + ct, ct->status); + if (nf_nat_oif_changed(state->hook, ctinfo, nat, + state->out)) + goto oif_changed; + } + break; + default: + /* ESTABLISHED */ + WARN_ON(ctinfo != IP_CT_ESTABLISHED && + ctinfo != IP_CT_ESTABLISHED_REPLY); + if (nf_nat_oif_changed(state->hook, ctinfo, nat, state->out)) + goto oif_changed; } - return NF_ACCEPT; +do_nat: + return nf_nat_packet(ct, ctinfo, state->hook, skb); + +oif_changed: + nf_ct_kill_acct(ct, ctinfo, skb); + return NF_DROP; } -EXPORT_SYMBOL_GPL(nf_nat_packet); +EXPORT_SYMBOL_GPL(nf_nat_inet_fn); struct nf_nat_proto_clean { u8 l3proto; @@ -702,7 +806,7 @@ static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = { static int nfnetlink_parse_nat_proto(struct nlattr *attr, const struct nf_conn *ct, - struct nf_nat_range *range) + struct nf_nat_range2 *range) { struct nlattr *tb[CTA_PROTONAT_MAX+1]; const struct nf_nat_l4proto *l4proto; @@ -730,7 +834,7 @@ static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = { static int nfnetlink_parse_nat(const struct nlattr *nat, - const struct nf_conn *ct, struct nf_nat_range *range, + const struct nf_conn *ct, struct nf_nat_range2 *range, const struct nf_nat_l3proto *l3proto) { struct nlattr *tb[CTA_NAT_MAX+1]; @@ -758,7 +862,7 @@ nfnetlink_parse_nat_setup(struct nf_conn *ct, enum nf_nat_manip_type manip, const struct nlattr *attr) { - struct nf_nat_range range; + struct nf_nat_range2 range; const struct nf_nat_l3proto *l3proto; int err; @@ -800,6 +904,146 @@ static struct nf_ct_helper_expectfn follow_master_nat = { .expectfn = nf_nat_follow_master, }; +int nf_nat_register_fn(struct net *net, const struct nf_hook_ops *ops, + const struct nf_hook_ops *orig_nat_ops, unsigned int ops_count) +{ + struct nat_net *nat_net = net_generic(net, nat_net_id); + struct nf_nat_hooks_net *nat_proto_net; + struct nf_nat_lookup_hook_priv *priv; + unsigned int hooknum = ops->hooknum; + struct nf_hook_ops *nat_ops; + int i, ret; + + if (WARN_ON_ONCE(ops->pf >= ARRAY_SIZE(nat_net->nat_proto_net))) + return -EINVAL; + + nat_proto_net = &nat_net->nat_proto_net[ops->pf]; + + for (i = 0; i < ops_count; i++) { + if (WARN_ON(orig_nat_ops[i].pf != ops->pf)) + return -EINVAL; + if (orig_nat_ops[i].hooknum == hooknum) { + hooknum = i; + break; + } + } + + if (WARN_ON_ONCE(i == ops_count)) + return -EINVAL; + + mutex_lock(&nf_nat_proto_mutex); + if (!nat_proto_net->nat_hook_ops) { + WARN_ON(nat_proto_net->users != 0); + + nat_ops = kmemdup(orig_nat_ops, sizeof(*orig_nat_ops) * ops_count, GFP_KERNEL); + if (!nat_ops) { + mutex_unlock(&nf_nat_proto_mutex); + return -ENOMEM; + } + + for (i = 0; i < ops_count; i++) { + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (priv) { + nat_ops[i].priv = priv; + continue; + } + mutex_unlock(&nf_nat_proto_mutex); + while (i) + kfree(nat_ops[--i].priv); + kfree(nat_ops); + return -ENOMEM; + } + + ret = nf_register_net_hooks(net, nat_ops, ops_count); + if (ret < 0) { + mutex_unlock(&nf_nat_proto_mutex); + for (i = 0; i < ops_count; i++) + kfree(nat_ops[i].priv); + kfree(nat_ops); + return ret; + } + + nat_proto_net->nat_hook_ops = nat_ops; + } + + nat_ops = nat_proto_net->nat_hook_ops; + priv = nat_ops[hooknum].priv; + if (WARN_ON_ONCE(!priv)) { + mutex_unlock(&nf_nat_proto_mutex); + return -EOPNOTSUPP; + } + + ret = nf_hook_entries_insert_raw(&priv->entries, ops); + if (ret == 0) + nat_proto_net->users++; + + mutex_unlock(&nf_nat_proto_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(nf_nat_register_fn); + +void nf_nat_unregister_fn(struct net *net, const struct nf_hook_ops *ops, + unsigned int ops_count) +{ + struct nat_net *nat_net = net_generic(net, nat_net_id); + struct nf_nat_hooks_net *nat_proto_net; + struct nf_nat_lookup_hook_priv *priv; + struct nf_hook_ops *nat_ops; + int hooknum = ops->hooknum; + int i; + + if (ops->pf >= ARRAY_SIZE(nat_net->nat_proto_net)) + return; + + nat_proto_net = &nat_net->nat_proto_net[ops->pf]; + + mutex_lock(&nf_nat_proto_mutex); + if (WARN_ON(nat_proto_net->users == 0)) + goto unlock; + + nat_proto_net->users--; + + nat_ops = nat_proto_net->nat_hook_ops; + for (i = 0; i < ops_count; i++) { + if (nat_ops[i].hooknum == hooknum) { + hooknum = i; + break; + } + } + if (WARN_ON_ONCE(i == ops_count)) + goto unlock; + priv = nat_ops[hooknum].priv; + nf_hook_entries_delete_raw(&priv->entries, ops); + + if (nat_proto_net->users == 0) { + nf_unregister_net_hooks(net, nat_ops, ops_count); + + for (i = 0; i < ops_count; i++) { + priv = nat_ops[i].priv; + kfree_rcu(priv, rcu_head); + } + + nat_proto_net->nat_hook_ops = NULL; + kfree(nat_ops); + } +unlock: + mutex_unlock(&nf_nat_proto_mutex); +} +EXPORT_SYMBOL_GPL(nf_nat_unregister_fn); + +static struct pernet_operations nat_net_ops = { + .id = &nat_net_id, + .size = sizeof(struct nat_net), +}; + +static struct nf_nat_hook nat_hook = { + .parse_nat_setup = nfnetlink_parse_nat_setup, +#ifdef CONFIG_XFRM + .decode_session = __nf_nat_decode_session, +#endif + .manip_pkt = nf_nat_manip_pkt, +}; + static int __init nf_nat_init(void) { int ret, i; @@ -823,15 +1067,17 @@ static int __init nf_nat_init(void) for (i = 0; i < CONNTRACK_LOCKS; i++) spin_lock_init(&nf_nat_locks[i]); + ret = register_pernet_subsys(&nat_net_ops); + if (ret < 0) { + nf_ct_extend_unregister(&nat_extend); + return ret; + } + nf_ct_helper_expectfn_register(&follow_master_nat); - 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 + WARN_ON(nf_nat_hook != NULL); + RCU_INIT_POINTER(nf_nat_hook, &nat_hook); + return 0; } @@ -844,16 +1090,15 @@ static void __exit nf_nat_cleanup(void) 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 + RCU_INIT_POINTER(nf_nat_hook, NULL); + synchronize_rcu(); for (i = 0; i < NFPROTO_NUMPROTO; i++) kfree(nf_nat_l4protos[i]); synchronize_net(); nf_ct_free_hashtable(nf_nat_bysource, nf_nat_htable_size); + unregister_pernet_subsys(&nat_net_ops); } MODULE_LICENSE("GPL"); |