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alistair23-linux/net/netfilter/nf_nat_core.c
David S. Miller a01aa920b8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 
Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset contains Netfilter updates for your net-next
tree. A large bunch of code cleanups, simplify the conntrack extension
codebase, get rid of the fake conntrack object, speed up netns by
selective synchronize_net() calls. More specifically, they are:

1) Check for ct->status bit instead of using nfct_nat() from IPVS and
   Netfilter codebase, patch from Florian Westphal.

2) Use kcalloc() wherever possible in the IPVS code, from Varsha Rao.

3) Simplify FTP IPVS helper module registration path, from Arushi Singhal.

4) Introduce nft_is_base_chain() helper function.

5) Enforce expectation limit from userspace conntrack helper,
   from Gao Feng.

6) Add nf_ct_remove_expect() helper function, from Gao Feng.

7) NAT mangle helper function return boolean, from Gao Feng.

8) ctnetlink_alloc_expect() should only work for conntrack with
   helpers, from Gao Feng.

9) Add nfnl_msg_type() helper function to nfnetlink to build the
   netlink message type.

10) Get rid of unnecessary cast on void, from simran singhal.

11) Use seq_puts()/seq_putc() instead of seq_printf() where possible,
    also from simran singhal.

12) Use list_prev_entry() from nf_tables, from simran signhal.

13) Remove unnecessary & on pointer function in the Netfilter and IPVS
    code.

14) Remove obsolete comment on set of rules per CPU in ip6_tables,
    no longer true. From Arushi Singhal.

15) Remove duplicated nf_conntrack_l4proto_udplite4, from Gao Feng.

16) Remove unnecessary nested rcu_read_lock() in
    __nf_nat_decode_session(). Code running from hooks are already
    guaranteed to run under RCU read side.

17) Remove deadcode in nf_tables_getobj(), from Aaron Conole.

18) Remove double assignment in nf_ct_l4proto_pernet_unregister_one(),
    also from Aaron.

19) Get rid of unsed __ip_set_get_netlink(), from Aaron Conole.

20) Don't propagate NF_DROP error to userspace via ctnetlink in
    __nf_nat_alloc_null_binding() function, from Gao Feng.

21) Revisit nf_ct_deliver_cached_events() to remove unnecessary checks,
    from Gao Feng.

22) Kill the fake untracked conntrack objects, use ctinfo instead to
    annotate a conntrack object is untracked, from Florian Westphal.

23) Remove nf_ct_is_untracked(), now obsolete since we have no
    conntrack template anymore, from Florian.

24) Add event mask support to nft_ct, also from Florian.

25) Move nf_conn_help structure to
    include/net/netfilter/nf_conntrack_helper.h.

26) Add a fixed 32 bytes scratchpad area for conntrack helpers.
    Thus, we don't deal with variable conntrack extensions anymore.
    Make sure userspace conntrack helper doesn't go over that size.
    Remove variable size ct extension infrastructure now this code
    got no more clients. From Florian Westphal.

27) Restore offset and length of nf_ct_ext structure to 8 bytes now
    that wraparound is not possible any longer, also from Florian.

28) Allow to get rid of unassured flows under stress in conntrack,
    this applies to DCCP, SCTP and TCP protocols, from Florian.

29) Shrink size of nf_conntrack_ecache structure, from Florian.

30) Use TCP_MAX_WSCALE instead of hardcoded 14 in TCP tracker,
    from Gao Feng.

31) Register SYNPROXY hooks on demand, from Florian Westphal.

32) Use pernet hook whenever possible, instead of global hook
    registration, from Florian Westphal.

33) Pass hook structure to ebt_register_table() to consolidate some
    infrastructure code, from Florian Westphal.

34) Use consume_skb() and return NF_STOLEN, instead of NF_DROP in the
    SYNPROXY code, to make sure device stats are not fooled, patch
    from Gao Feng.

35) Remove NF_CT_EXT_F_PREALLOC this kills quite some code that we
    don't need anymore if we just select a fixed size instead of
    expensive runtime time calculation of this. From Florian.

36) Constify nf_ct_extend_register() and nf_ct_extend_unregister(),
    from Florian.

37) Simplify nf_ct_ext_add(), this kills nf_ct_ext_create(), from
    Florian.

38) Attach NAT extension on-demand from masquerade and pptp helper
    path, from Florian.

39) Get rid of useless ip_vs_set_state_timeout(), from Aaron Conole.

40) Speed up netns by selective calls of synchronize_net(), from
    Florian Westphal.

41) Silence stack size warning gcc in 32-bit arch in snmp helper,
    from Florian.

42) Inconditionally call nf_ct_ext_destroy(), even if we have no
    extensions, to deal with the NF_NAT_MANIP_SRC case. Patch from
    Liping Zhang.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-01 10:47:53 -04:00

896 lines
24 KiB
C
Raw Blame History

/*
* (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_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;
struct nf_nat_conn_key {
const struct net *net;
const struct nf_conntrack_tuple *tuple;
const struct nf_conntrack_zone *zone;
};
static struct rhltable nf_nat_bysource_table;
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 = nf_ct_l3num(ct);
l3proto = __nf_nat_l3proto_find(family);
if (l3proto == NULL)
return;
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);
}
int nf_xfrm_me_harder(struct net *net, 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(net, 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 */
static u32 nf_nat_bysource_hash(const void *data, u32 len, u32 seed)
{
const struct nf_conntrack_tuple *t;
const struct nf_conn *ct = data;
t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
/* Original src, to ensure we map it consistently if poss. */
seed ^= net_hash_mix(nf_ct_net(ct));
return jhash2((const u32 *)&t->src, sizeof(t->src) / sizeof(u32),
t->dst.protonum ^ seed);
}
/* 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);
}
static int nf_nat_bysource_cmp(struct rhashtable_compare_arg *arg,
const void *obj)
{
const struct nf_nat_conn_key *key = arg->key;
const struct nf_conn *ct = obj;
if (!same_src(ct, key->tuple) ||
!net_eq(nf_ct_net(ct), key->net) ||
!nf_ct_zone_equal(ct, key->zone, IP_CT_DIR_ORIGINAL))
return 1;
return 0;
}
static struct rhashtable_params nf_nat_bysource_params = {
.head_offset = offsetof(struct nf_conn, nat_bysource),
.obj_hashfn = nf_nat_bysource_hash,
.obj_cmpfn = nf_nat_bysource_cmp,
.nelem_hint = 256,
.min_size = 1024,
};
/* Only called for SRC manip */
static int
find_appropriate_src(struct net *net,
const struct nf_conntrack_zone *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)
{
const struct nf_conn *ct;
struct nf_nat_conn_key key = {
.net = net,
.tuple = tuple,
.zone = zone
};
struct rhlist_head *hl;
hl = rhltable_lookup(&nf_nat_bysource_table, &key,
nf_nat_bysource_params);
if (!hl)
return 0;
ct = container_of(hl, typeof(*ct), nat_bysource);
nf_ct_invert_tuplepr(result,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
result->dst = tuple->dst;
return in_range(l3proto, l4proto, result, range);
}
/* 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(const struct nf_conntrack_zone *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->id);
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_conntrack_zone *zone;
const struct nf_nat_l3proto *l3proto;
const struct nf_nat_l4proto *l4proto;
struct net *net = nf_ct_net(ct);
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 nf_conntrack_tuple curr_tuple, new_tuple;
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))
if (!nfct_seqadj_ext_add(ct))
return NF_DROP;
}
if (maniptype == NF_NAT_MANIP_SRC) {
struct nf_nat_conn_key key = {
.net = nf_ct_net(ct),
.tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
.zone = nf_ct_zone(ct),
};
int err;
err = rhltable_insert_key(&nf_nat_bysource_table,
&key,
&ct->nat_bysource,
nf_nat_bysource_params);
if (err)
return NF_DROP;
}
/* 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;
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)
{
if (nf_nat_proto_remove(ct, data))
return 1;
if ((ct->status & IPS_SRC_NAT_DONE) == 0)
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.
*/
ct->status &= ~IPS_NAT_DONE_MASK;
rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
nf_nat_bysource_params);
/* 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);
#ifdef CONFIG_NF_NAT_PROTO_DCCP
RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_DCCP],
&nf_nat_l4proto_dccp);
#endif
#ifdef CONFIG_NF_NAT_PROTO_SCTP
RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_SCTP],
&nf_nat_l4proto_sctp);
#endif
#ifdef CONFIG_NF_NAT_PROTO_UDPLITE
RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_UDPLITE],
&nf_nat_l4proto_udplite);
#endif
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)
{
if (ct->status & IPS_SRC_NAT_DONE)
rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
nf_nat_bysource_params);
}
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,
.id = NF_CT_EXT_NAT,
};
#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, NULL);
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, NULL);
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) == NF_DROP ? -ENOMEM : 0;
err = nfnetlink_parse_nat(attr, ct, &range, l3proto);
if (err < 0)
return err;
return nf_nat_setup_info(ct, &range, manip) == NF_DROP ? -ENOMEM : 0;
}
#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 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);
}
static struct pernet_operations nf_nat_net_ops = {
.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 = rhltable_init(&nf_nat_bysource_table, &nf_nat_bysource_params);
if (ret)
return ret;
ret = nf_ct_extend_register(&nat_extend);
if (ret < 0) {
rhltable_destroy(&nf_nat_bysource_table);
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);
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:
rhltable_destroy(&nf_nat_bysource_table);
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
synchronize_rcu();
for (i = 0; i < NFPROTO_NUMPROTO; i++)
kfree(nf_nat_l4protos[i]);
rhltable_destroy(&nf_nat_bysource_table);
}
MODULE_LICENSE("GPL");
module_init(nf_nat_init);
module_exit(nf_nat_cleanup);
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