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Date: Wed, 10 Sep 2014 17:10:26 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 09/25] netfilter: nat: move specific NAT IPv4 to core
Move the specific NAT IPv4 core functions that are called from the
hooks from iptable_nat.c to nf_nat_l3proto_ipv4.c. This prepares the
ground to allow iptables and nft to use the same NAT engine code that
comes in a follow up patch.
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/nf_nat_l3proto.h | 38 +++++
net/ipv4/netfilter/iptable_nat.c | 233 +++++-------------------------
net/ipv4/netfilter/nf_nat_l3proto_ipv4.c | 199 +++++++++++++++++++++++++
3 files changed, 271 insertions(+), 199 deletions(-)
diff --git a/include/net/netfilter/nf_nat_l3proto.h b/include/net/netfilter/nf_nat_l3proto.h
index 5a2919b..bc2d515 100644
--- a/include/net/netfilter/nf_nat_l3proto.h
+++ b/include/net/netfilter/nf_nat_l3proto.h
@@ -42,6 +42,44 @@ const struct nf_nat_l3proto *__nf_nat_l3proto_find(u8 l3proto);
int nf_nat_icmp_reply_translation(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int hooknum);
+
+unsigned int nf_nat_ipv4_in(const struct nf_hook_ops *ops, struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct));
+
+unsigned int nf_nat_ipv4_out(const struct nf_hook_ops *ops, struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct));
+
+unsigned int nf_nat_ipv4_local_fn(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct));
+
+unsigned int nf_nat_ipv4_fn(const struct nf_hook_ops *ops, struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct));
+
int nf_nat_icmpv6_reply_translation(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int hooknum, unsigned int hdrlen);
diff --git a/net/ipv4/netfilter/iptable_nat.c b/net/ipv4/netfilter/iptable_nat.c
index f1787c0..6b67d7e 100644
--- a/net/ipv4/netfilter/iptable_nat.c
+++ b/net/ipv4/netfilter/iptable_nat.c
@@ -28,222 +28,57 @@ static const struct xt_table nf_nat_ipv4_table = {
.af = NFPROTO_IPV4,
};
-static unsigned int alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
-{
- /* Force range to this IP; let proto decide mapping for
- * per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
- */
- struct nf_nat_range range;
-
- range.flags = 0;
- pr_debug("Allocating NULL binding for %p (%pI4)\n", ct,
- HOOK2MANIP(hooknum) == NF_NAT_MANIP_SRC ?
- &ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip :
- &ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip);
-
- return nf_nat_setup_info(ct, &range, HOOK2MANIP(hooknum));
-}
-
-static unsigned int nf_nat_rule_find(struct sk_buff *skb, unsigned int hooknum,
- const struct net_device *in,
- const struct net_device *out,
- struct nf_conn *ct)
+static unsigned int iptable_nat_do_chain(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
- unsigned int ret;
- ret = ipt_do_table(skb, hooknum, in, out, net->ipv4.nat_table);
- if (ret == NF_ACCEPT) {
- if (!nf_nat_initialized(ct, HOOK2MANIP(hooknum)))
- ret = alloc_null_binding(ct, hooknum);
- }
- return ret;
+ return ipt_do_table(skb, ops->hooknum, in, out, net->ipv4.nat_table);
}
-static unsigned int
-nf_nat_ipv4_fn(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
+static unsigned int iptable_nat_ipv4_fn(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ int (*okfn)(struct sk_buff *))
{
- 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(ops->hooknum);
-
- /* We never see fragments: conntrack defrags on pre-routing
- * and local-out, and nf_nat_out protects post-routing.
- */
- NF_CT_ASSERT(!ip_is_fragment(ip_hdr(skb)));
-
- 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;
-
- /* Don't try to NAT if this packet is not conntracked */
- if (nf_ct_is_untracked(ct))
- return NF_ACCEPT;
-
- nat = nf_ct_nat_ext_add(ct);
- if (nat == NULL)
- return NF_ACCEPT;
-
- switch (ctinfo) {
- case IP_CT_RELATED:
- case IP_CT_RELATED_REPLY:
- if (ip_hdr(skb)->protocol == IPPROTO_ICMP) {
- if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
- ops->hooknum))
- return NF_DROP;
- else
- return NF_ACCEPT;
- }
- /* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
- case IP_CT_NEW:
- /* Seen it before? This can happen for loopback, retrans,
- * or local packets.
- */
- if (!nf_nat_initialized(ct, maniptype)) {
- unsigned int ret;
-
- ret = nf_nat_rule_find(skb, ops->hooknum, in, out, ct);
- if (ret != NF_ACCEPT)
- return ret;
- } else {
- pr_debug("Already setup manip %s for ct %p\n",
- maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
- ct);
- if (nf_nat_oif_changed(ops->hooknum, ctinfo, nat, out))
- goto oif_changed;
- }
- break;
-
- default:
- /* ESTABLISHED */
- NF_CT_ASSERT(ctinfo == IP_CT_ESTABLISHED ||
- ctinfo == IP_CT_ESTABLISHED_REPLY);
- if (nf_nat_oif_changed(ops->hooknum, ctinfo, nat, out))
- goto oif_changed;
- }
-
- return nf_nat_packet(ct, ctinfo, ops->hooknum, skb);
-
-oif_changed:
- nf_ct_kill_acct(ct, ctinfo, skb);
- return NF_DROP;
+ return nf_nat_ipv4_fn(ops, skb, in, out, iptable_nat_do_chain);
}
-static unsigned int
-nf_nat_ipv4_in(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
+static unsigned int iptable_nat_ipv4_in(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ int (*okfn)(struct sk_buff *))
{
- unsigned int ret;
- __be32 daddr = ip_hdr(skb)->daddr;
-
- ret = nf_nat_ipv4_fn(ops, skb, in, out, okfn);
- if (ret != NF_DROP && ret != NF_STOLEN &&
- daddr != ip_hdr(skb)->daddr)
- skb_dst_drop(skb);
-
- return ret;
+ return nf_nat_ipv4_in(ops, skb, in, out, iptable_nat_do_chain);
}
-static unsigned int
-nf_nat_ipv4_out(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
+static unsigned int iptable_nat_ipv4_out(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ int (*okfn)(struct sk_buff *))
{
-#ifdef CONFIG_XFRM
- const struct nf_conn *ct;
- enum ip_conntrack_info ctinfo;
- int err;
-#endif
- unsigned int ret;
-
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr))
- return NF_ACCEPT;
-
- ret = nf_nat_ipv4_fn(ops, skb, in, out, okfn);
-#ifdef CONFIG_XFRM
- if (ret != NF_DROP && ret != NF_STOLEN &&
- !(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
- (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
- enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
-
- if ((ct->tuplehash[dir].tuple.src.u3.ip !=
- ct->tuplehash[!dir].tuple.dst.u3.ip) ||
- (ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMP &&
- ct->tuplehash[dir].tuple.src.u.all !=
- ct->tuplehash[!dir].tuple.dst.u.all)) {
- err = nf_xfrm_me_harder(skb, AF_INET);
- if (err < 0)
- ret = NF_DROP_ERR(err);
- }
- }
-#endif
- return ret;
+ return nf_nat_ipv4_out(ops, skb, in, out, iptable_nat_do_chain);
}
-static unsigned int
-nf_nat_ipv4_local_fn(const struct nf_hook_ops *ops,
- struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
+static unsigned int iptable_nat_ipv4_local_fn(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ int (*okfn)(struct sk_buff *))
{
- const struct nf_conn *ct;
- enum ip_conntrack_info ctinfo;
- unsigned int ret;
- int err;
-
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr))
- return NF_ACCEPT;
-
- ret = nf_nat_ipv4_fn(ops, skb, in, out, okfn);
- if (ret != NF_DROP && ret != NF_STOLEN &&
- (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
- enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
-
- if (ct->tuplehash[dir].tuple.dst.u3.ip !=
- ct->tuplehash[!dir].tuple.src.u3.ip) {
- err = ip_route_me_harder(skb, RTN_UNSPEC);
- if (err < 0)
- ret = NF_DROP_ERR(err);
- }
-#ifdef CONFIG_XFRM
- else if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
- ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMP &&
- ct->tuplehash[dir].tuple.dst.u.all !=
- ct->tuplehash[!dir].tuple.src.u.all) {
- err = nf_xfrm_me_harder(skb, AF_INET);
- if (err < 0)
- ret = NF_DROP_ERR(err);
- }
-#endif
- }
- return ret;
+ return nf_nat_ipv4_local_fn(ops, skb, in, out, iptable_nat_do_chain);
}
static struct nf_hook_ops nf_nat_ipv4_ops[] __read_mostly = {
/* Before packet filtering, change destination */
{
- .hook = nf_nat_ipv4_in,
+ .hook = iptable_nat_ipv4_in,
.owner = THIS_MODULE,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_PRE_ROUTING,
@@ -251,7 +86,7 @@ static struct nf_hook_ops nf_nat_ipv4_ops[] __read_mostly = {
},
/* After packet filtering, change source */
{
- .hook = nf_nat_ipv4_out,
+ .hook = iptable_nat_ipv4_out,
.owner = THIS_MODULE,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_POST_ROUTING,
@@ -259,7 +94,7 @@ static struct nf_hook_ops nf_nat_ipv4_ops[] __read_mostly = {
},
/* Before packet filtering, change destination */
{
- .hook = nf_nat_ipv4_local_fn,
+ .hook = iptable_nat_ipv4_local_fn,
.owner = THIS_MODULE,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_OUT,
@@ -267,7 +102,7 @@ static struct nf_hook_ops nf_nat_ipv4_ops[] __read_mostly = {
},
/* After packet filtering, change source */
{
- .hook = nf_nat_ipv4_fn,
+ .hook = iptable_nat_ipv4_fn,
.owner = THIS_MODULE,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_IN,
diff --git a/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c b/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
index 14f5ccd..fc37711 100644
--- a/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
@@ -254,6 +254,205 @@ int nf_nat_icmp_reply_translation(struct sk_buff *skb,
}
EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
+unsigned int
+nf_nat_ipv4_fn(const struct nf_hook_ops *ops, struct sk_buff *skb,
+ const struct net_device *in, const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct))
+{
+ 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(ops->hooknum);
+
+ /* We never see fragments: conntrack defrags on pre-routing
+ * and local-out, and nf_nat_out protects post-routing.
+ */
+ NF_CT_ASSERT(!ip_is_fragment(ip_hdr(skb)));
+
+ 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;
+
+ /* Don't try to NAT if this packet is not conntracked */
+ if (nf_ct_is_untracked(ct))
+ return NF_ACCEPT;
+
+ nat = nf_ct_nat_ext_add(ct);
+ if (nat == NULL)
+ return NF_ACCEPT;
+
+ switch (ctinfo) {
+ case IP_CT_RELATED:
+ case IP_CT_RELATED_REPLY:
+ if (ip_hdr(skb)->protocol == IPPROTO_ICMP) {
+ if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
+ ops->hooknum))
+ return NF_DROP;
+ else
+ return NF_ACCEPT;
+ }
+ /* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
+ case IP_CT_NEW:
+ /* Seen it before? This can happen for loopback, retrans,
+ * or local packets.
+ */
+ if (!nf_nat_initialized(ct, maniptype)) {
+ unsigned int ret;
+
+ ret = do_chain(ops, skb, in, out, ct);
+ if (ret != NF_ACCEPT)
+ return ret;
+
+ if (nf_nat_initialized(ct, HOOK2MANIP(ops->hooknum)))
+ break;
+
+ ret = nf_nat_alloc_null_binding(ct, ops->hooknum);
+ if (ret != NF_ACCEPT)
+ return ret;
+ } else {
+ pr_debug("Already setup manip %s for ct %p\n",
+ maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
+ ct);
+ if (nf_nat_oif_changed(ops->hooknum, ctinfo, nat, out))
+ goto oif_changed;
+ }
+ break;
+
+ default:
+ /* ESTABLISHED */
+ NF_CT_ASSERT(ctinfo == IP_CT_ESTABLISHED ||
+ ctinfo == IP_CT_ESTABLISHED_REPLY);
+ if (nf_nat_oif_changed(ops->hooknum, ctinfo, nat, out))
+ goto oif_changed;
+ }
+
+ return nf_nat_packet(ct, ctinfo, ops->hooknum, skb);
+
+oif_changed:
+ nf_ct_kill_acct(ct, ctinfo, skb);
+ return NF_DROP;
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv4_fn);
+
+unsigned int
+nf_nat_ipv4_in(const struct nf_hook_ops *ops, struct sk_buff *skb,
+ const struct net_device *in, const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct))
+{
+ unsigned int ret;
+ __be32 daddr = ip_hdr(skb)->daddr;
+
+ ret = nf_nat_ipv4_fn(ops, skb, in, out, do_chain);
+ if (ret != NF_DROP && ret != NF_STOLEN &&
+ daddr != ip_hdr(skb)->daddr)
+ skb_dst_drop(skb);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv4_in);
+
+unsigned int
+nf_nat_ipv4_out(const struct nf_hook_ops *ops, struct sk_buff *skb,
+ const struct net_device *in, const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct))
+{
+#ifdef CONFIG_XFRM
+ const struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ int err;
+#endif
+ unsigned int ret;
+
+ /* root is playing with raw sockets. */
+ if (skb->len < sizeof(struct iphdr) ||
+ ip_hdrlen(skb) < sizeof(struct iphdr))
+ return NF_ACCEPT;
+
+ ret = nf_nat_ipv4_fn(ops, skb, in, out, do_chain);
+#ifdef CONFIG_XFRM
+ if (ret != NF_DROP && ret != NF_STOLEN &&
+ !(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
+ (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if ((ct->tuplehash[dir].tuple.src.u3.ip !=
+ ct->tuplehash[!dir].tuple.dst.u3.ip) ||
+ (ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMP &&
+ ct->tuplehash[dir].tuple.src.u.all !=
+ ct->tuplehash[!dir].tuple.dst.u.all)) {
+ err = nf_xfrm_me_harder(skb, AF_INET);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+ }
+#endif
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv4_out);
+
+unsigned int
+nf_nat_ipv4_local_fn(const struct nf_hook_ops *ops, struct sk_buff *skb,
+ const struct net_device *in, const struct net_device *out,
+ unsigned int (*do_chain)(const struct nf_hook_ops *ops,
+ struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ struct nf_conn *ct))
+{
+ const struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ unsigned int ret;
+ int err;
+
+ /* root is playing with raw sockets. */
+ if (skb->len < sizeof(struct iphdr) ||
+ ip_hdrlen(skb) < sizeof(struct iphdr))
+ return NF_ACCEPT;
+
+ ret = nf_nat_ipv4_fn(ops, skb, in, out, do_chain);
+ if (ret != NF_DROP && ret != NF_STOLEN &&
+ (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if (ct->tuplehash[dir].tuple.dst.u3.ip !=
+ ct->tuplehash[!dir].tuple.src.u3.ip) {
+ err = ip_route_me_harder(skb, RTN_UNSPEC);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+#ifdef CONFIG_XFRM
+ else if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
+ ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMP &&
+ ct->tuplehash[dir].tuple.dst.u.all !=
+ ct->tuplehash[!dir].tuple.src.u.all) {
+ err = nf_xfrm_me_harder(skb, AF_INET);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+#endif
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv4_local_fn);
+
static int __init nf_nat_l3proto_ipv4_init(void)
{
int err;
--
1.7.10.4
--
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