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net: move the nat function to nf_nat_ovs for ovs and tc

Browse source 
There are two nat functions are nearly the same in both OVS and
TC code, (ovs_)ct_nat_execute() and ovs_ct_nat/tcf_ct_act_nat().

This patch creates nf_nat_ovs.c under netfilter and moves them
there then exports nf_ct_nat() so that it can be shared by both
OVS and TC, and keeps the nat (type) check and nat flag update
in OVS and TC's own place, as these parts are different between
OVS and TC.

Note that in OVS nat function it was using skb->protocol to get
the proto as it already skips vlans in key_extract(), while it
doesn't in TC, and TC has to call skb_protocol() to get proto.
So in nf_ct_nat_execute(), we keep using skb_protocol() which
works for both OVS and TC contrack.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Aaron Conole <aconole@redhat.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Xin Long 2022-12-08 11:56:12 -05:00 committed by David S. Miller
parent 0564c3e51b
commit ebddb14049
8 changed files with 165 additions and 251 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
include/net/netfilter/nf_nat.h
View file

@ -104,6 +104,10 @@ unsigned int
nf_nat_inet_fn(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state);
int nf_ct_nat(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo, int *action,
const struct nf_nat_range2 *range, bool commit);
static inline int nf_nat_initialized(const struct nf_conn *ct,
enum nf_nat_manip_type manip)
{

3
net/netfilter/Kconfig
View file

@ -459,6 +459,9 @@ config NF_NAT_REDIRECT
config NF_NAT_MASQUERADE
bool
config NF_NAT_OVS
bool
config NETFILTER_SYNPROXY
tristate

1
net/netfilter/Makefile
View file

@ -59,6 +59,7 @@ obj-$(CONFIG_NF_LOG_SYSLOG) += nf_log_syslog.o
obj-$(CONFIG_NF_NAT) += nf_nat.o
nf_nat-$(CONFIG_NF_NAT_REDIRECT) += nf_nat_redirect.o
nf_nat-$(CONFIG_NF_NAT_MASQUERADE) += nf_nat_masquerade.o
nf_nat-$(CONFIG_NF_NAT_OVS) += nf_nat_ovs.o
ifeq ($(CONFIG_NF_NAT),m)
nf_nat-$(CONFIG_DEBUG_INFO_BTF_MODULES) += nf_nat_bpf.o

135
net/netfilter/nf_nat_ovs.c Normal file
View file

@ -0,0 +1,135 @@
// SPDX-License-Identifier: GPL-2.0-only
/* Support nat functions for openvswitch and used by OVS and TC conntrack. */
#include <net/netfilter/nf_nat.h>
/* Modelled after nf_nat_ipv[46]_fn().
* range is only used for new, uninitialized NAT state.
* Returns either NF_ACCEPT or NF_DROP.
*/
static int nf_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo, int *action,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype)
{
__be16 proto = skb_protocol(skb, true);
int hooknum, err = NF_ACCEPT;
/* See HOOK2MANIP(). */
if (maniptype == NF_NAT_MANIP_SRC)
hooknum = NF_INET_LOCAL_IN; /* Source NAT */
else
hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
switch (ctinfo) {
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
if (proto == htons(ETH_P_IP) &&
ip_hdr(skb)->protocol == IPPROTO_ICMP) {
if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
hooknum))
err = NF_DROP;
goto out;
} else if (IS_ENABLED(CONFIG_IPV6) && proto == htons(ETH_P_IPV6)) {
__be16 frag_off;
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
int hdrlen = ipv6_skip_exthdr(skb,
sizeof(struct ipv6hdr),
&nexthdr, &frag_off);
if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
if (!nf_nat_icmpv6_reply_translation(skb, ct,
ctinfo,
hooknum,
hdrlen))
err = NF_DROP;
goto out;
}
}
/* Non-ICMP, fall thru to initialize if needed. */
fallthrough;
case IP_CT_NEW:
/* Seen it before? This can happen for loopback, retrans,
* or local packets.
*/
if (!nf_nat_initialized(ct, maniptype)) {
/* Initialize according to the NAT action. */
err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
/* Action is set up to establish a new
* mapping.
*/
? nf_nat_setup_info(ct, range, maniptype)
: nf_nat_alloc_null_binding(ct, hooknum);
if (err != NF_ACCEPT)
goto out;
}
break;
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
break;
default:
err = NF_DROP;
goto out;
}
err = nf_nat_packet(ct, ctinfo, hooknum, skb);
if (err == NF_ACCEPT)
*action |= BIT(maniptype);
out:
return err;
}
int nf_ct_nat(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo, int *action,
const struct nf_nat_range2 *range, bool commit)
{
enum nf_nat_manip_type maniptype;
int err, ct_action = *action;
*action = 0;
/* Add NAT extension if not confirmed yet. */
if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
return NF_DROP; /* Can't NAT. */
if (ctinfo != IP_CT_NEW && (ct->status & IPS_NAT_MASK) &&
(ctinfo != IP_CT_RELATED || commit)) {
/* NAT an established or related connection like before. */
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
/* This is the REPLY direction for a connection
* for which NAT was applied in the forward
* direction. Do the reverse NAT.
*/
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
else
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
} else if (ct_action & BIT(NF_NAT_MANIP_SRC)) {
maniptype = NF_NAT_MANIP_SRC;
} else if (ct_action & BIT(NF_NAT_MANIP_DST)) {
maniptype = NF_NAT_MANIP_DST;
} else {
return NF_ACCEPT;
}
err = nf_ct_nat_execute(skb, ct, ctinfo, action, range, maniptype);
if (err == NF_ACCEPT && ct->status & IPS_DST_NAT) {
if (ct->status & IPS_SRC_NAT) {
if (maniptype == NF_NAT_MANIP_SRC)
maniptype = NF_NAT_MANIP_DST;
else
maniptype = NF_NAT_MANIP_SRC;
err = nf_ct_nat_execute(skb, ct, ctinfo, action, range,
maniptype);
} else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
err = nf_ct_nat_execute(skb, ct, ctinfo, action, NULL,
NF_NAT_MANIP_SRC);
}
}
return err;
}
EXPORT_SYMBOL_GPL(nf_ct_nat);

1
net/openvswitch/Kconfig
View file

@ -15,6 +15,7 @@ config OPENVSWITCH
select NET_MPLS_GSO
select DST_CACHE
select NET_NSH
select NF_NAT_OVS if NF_NAT
help
Open vSwitch is a multilayer Ethernet switch targeted at virtualized
environments. In addition to supporting a variety of features

137
net/openvswitch/conntrack.c
View file

@ -726,144 +726,27 @@ static void ovs_nat_update_key(struct sw_flow_key *key,
}
}
/* Modelled after nf_nat_ipv[46]_fn().
* range is only used for new, uninitialized NAT state.
* Returns either NF_ACCEPT or NF_DROP.
*/
static int ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype, struct sw_flow_key *key)
{
int hooknum, err = NF_ACCEPT;
/* See HOOK2MANIP(). */
if (maniptype == NF_NAT_MANIP_SRC)
hooknum = NF_INET_LOCAL_IN; /* Source NAT */
else
hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
switch (ctinfo) {
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
if (IS_ENABLED(CONFIG_NF_NAT) &&
skb->protocol == htons(ETH_P_IP) &&
ip_hdr(skb)->protocol == IPPROTO_ICMP) {
if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
hooknum))
err = NF_DROP;
goto out;
} else if (IS_ENABLED(CONFIG_IPV6) &&
skb->protocol == htons(ETH_P_IPV6)) {
__be16 frag_off;
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
int hdrlen = ipv6_skip_exthdr(skb,
sizeof(struct ipv6hdr),
&nexthdr, &frag_off);
if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
if (!nf_nat_icmpv6_reply_translation(skb, ct,
ctinfo,
hooknum,
hdrlen))
err = NF_DROP;
goto out;
}
}
/* Non-ICMP, fall thru to initialize if needed. */
fallthrough;
case IP_CT_NEW:
/* Seen it before? This can happen for loopback, retrans,
* or local packets.
*/
if (!nf_nat_initialized(ct, maniptype)) {
/* Initialize according to the NAT action. */
err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
/* Action is set up to establish a new
* mapping.
*/
? nf_nat_setup_info(ct, range, maniptype)
: nf_nat_alloc_null_binding(ct, hooknum);
if (err != NF_ACCEPT)
goto out;
}
break;
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
break;
default:
err = NF_DROP;
goto out;
}
err = nf_nat_packet(ct, ctinfo, hooknum, skb);
out:
/* Update the flow key if NAT successful. */
if (err == NF_ACCEPT)
ovs_nat_update_key(key, skb, maniptype);
return err;
}
/* Returns NF_DROP if the packet should be dropped, NF_ACCEPT otherwise. */
static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
enum nf_nat_manip_type maniptype;
int err;
int err, action = 0;
if (!(info->nat & OVS_CT_NAT))
return NF_ACCEPT;
if (info->nat & OVS_CT_SRC_NAT)
action |= BIT(NF_NAT_MANIP_SRC);
if (info->nat & OVS_CT_DST_NAT)
action |= BIT(NF_NAT_MANIP_DST);
/* Add NAT extension if not confirmed yet. */
if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
return NF_DROP; /* Can't NAT. */
err = nf_ct_nat(skb, ct, ctinfo, &action, &info->range, info->commit);
/* Determine NAT type.
* Check if the NAT type can be deduced from the tracked connection.
* Make sure new expected connections (IP_CT_RELATED) are NATted only
* when committing.
*/
if (ctinfo != IP_CT_NEW && ct->status & IPS_NAT_MASK &&
(ctinfo != IP_CT_RELATED || info->commit)) {
/* NAT an established or related connection like before. */
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
/* This is the REPLY direction for a connection
* for which NAT was applied in the forward
* direction. Do the reverse NAT.
*/
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
else
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
} else if (info->nat & OVS_CT_SRC_NAT) {
maniptype = NF_NAT_MANIP_SRC;
} else if (info->nat & OVS_CT_DST_NAT) {
maniptype = NF_NAT_MANIP_DST;
} else {
return NF_ACCEPT; /* Connection is not NATed. */
}
err = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range, maniptype, key);
if (err == NF_ACCEPT && ct->status & IPS_DST_NAT) {
if (ct->status & IPS_SRC_NAT) {
if (maniptype == NF_NAT_MANIP_SRC)
maniptype = NF_NAT_MANIP_DST;
else
maniptype = NF_NAT_MANIP_SRC;
err = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range,
maniptype, key);
} else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
err = ovs_ct_nat_execute(skb, ct, ctinfo, NULL,
NF_NAT_MANIP_SRC, key);
}
}
if (action & BIT(NF_NAT_MANIP_SRC))
ovs_nat_update_key(key, skb, NF_NAT_MANIP_SRC);
if (action & BIT(NF_NAT_MANIP_DST))
ovs_nat_update_key(key, skb, NF_NAT_MANIP_DST);
return err;
}

1
net/sched/Kconfig
View file

@ -977,6 +977,7 @@ config NET_ACT_TUNNEL_KEY
config NET_ACT_CT
tristate "connection tracking tc action"
depends on NET_CLS_ACT && NF_CONNTRACK && (!NF_NAT || NF_NAT) && NF_FLOW_TABLE
select NF_NAT_OVS if NF_NAT
help
Say Y here to allow sending the packets to conntrack module.

134
net/sched/act_ct.c
View file

@ -864,90 +864,6 @@ static void tcf_ct_params_free_rcu(struct rcu_head *head)
tcf_ct_params_free(params);
}
#if IS_ENABLED(CONFIG_NF_NAT)
/* Modelled after nf_nat_ipv[46]_fn().
* range is only used for new, uninitialized NAT state.
* Returns either NF_ACCEPT or NF_DROP.
*/
static int ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype)
{
__be16 proto = skb_protocol(skb, true);
int hooknum, err = NF_ACCEPT;
/* See HOOK2MANIP(). */
if (maniptype == NF_NAT_MANIP_SRC)
hooknum = NF_INET_LOCAL_IN; /* Source NAT */
else
hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
switch (ctinfo) {
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
if (proto == htons(ETH_P_IP) &&
ip_hdr(skb)->protocol == IPPROTO_ICMP) {
if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
hooknum))
err = NF_DROP;
goto out;
} else if (IS_ENABLED(CONFIG_IPV6) && proto == htons(ETH_P_IPV6)) {
__be16 frag_off;
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
int hdrlen = ipv6_skip_exthdr(skb,
sizeof(struct ipv6hdr),
&nexthdr, &frag_off);
if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
if (!nf_nat_icmpv6_reply_translation(skb, ct,
ctinfo,
hooknum,
hdrlen))
err = NF_DROP;
goto out;
}
}
/* Non-ICMP, fall thru to initialize if needed. */
fallthrough;
case IP_CT_NEW:
/* Seen it before? This can happen for loopback, retrans,
* or local packets.
*/
if (!nf_nat_initialized(ct, maniptype)) {
/* Initialize according to the NAT action. */
err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
/* Action is set up to establish a new
* mapping.
*/
? nf_nat_setup_info(ct, range, maniptype)
: nf_nat_alloc_null_binding(ct, hooknum);
if (err != NF_ACCEPT)
goto out;
}
break;
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
break;
default:
err = NF_DROP;
goto out;
}
err = nf_nat_packet(ct, ctinfo, hooknum, skb);
out:
if (err == NF_ACCEPT) {
if (maniptype == NF_NAT_MANIP_SRC)
tc_skb_cb(skb)->post_ct_snat = 1;
if (maniptype == NF_NAT_MANIP_DST)
tc_skb_cb(skb)->post_ct_dnat = 1;
}
return err;
}
#endif /* CONFIG_NF_NAT */
static void tcf_ct_act_set_mark(struct nf_conn *ct, u32 mark, u32 mask)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
@ -987,52 +903,22 @@ static int tcf_ct_act_nat(struct sk_buff *skb,
bool commit)
{
#if IS_ENABLED(CONFIG_NF_NAT)
int err;
enum nf_nat_manip_type maniptype;
int err, action = 0;
if (!(ct_action & TCA_CT_ACT_NAT))
return NF_ACCEPT;
if (ct_action & TCA_CT_ACT_NAT_SRC)
action |= BIT(NF_NAT_MANIP_SRC);
if (ct_action & TCA_CT_ACT_NAT_DST)
action |= BIT(NF_NAT_MANIP_DST);
/* Add NAT extension if not confirmed yet. */
if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
return NF_DROP; /* Can't NAT. */
err = nf_ct_nat(skb, ct, ctinfo, &action, range, commit);
if (ctinfo != IP_CT_NEW && (ct->status & IPS_NAT_MASK) &&
(ctinfo != IP_CT_RELATED || commit)) {
/* NAT an established or related connection like before. */
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
/* This is the REPLY direction for a connection
* for which NAT was applied in the forward
* direction. Do the reverse NAT.
*/
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
else
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
} else if (ct_action & TCA_CT_ACT_NAT_SRC) {
maniptype = NF_NAT_MANIP_SRC;
} else if (ct_action & TCA_CT_ACT_NAT_DST) {
maniptype = NF_NAT_MANIP_DST;
} else {
return NF_ACCEPT;
}
if (action & BIT(NF_NAT_MANIP_SRC))
tc_skb_cb(skb)->post_ct_snat = 1;
if (action & BIT(NF_NAT_MANIP_DST))
tc_skb_cb(skb)->post_ct_dnat = 1;
err = ct_nat_execute(skb, ct, ctinfo, range, maniptype);
if (err == NF_ACCEPT && ct->status & IPS_DST_NAT) {
if (ct->status & IPS_SRC_NAT) {
if (maniptype == NF_NAT_MANIP_SRC)
maniptype = NF_NAT_MANIP_DST;
else
maniptype = NF_NAT_MANIP_SRC;
err = ct_nat_execute(skb, ct, ctinfo, range,
maniptype);
} else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
err = ct_nat_execute(skb, ct, ctinfo, NULL,
NF_NAT_MANIP_SRC);
}
}
return err;
#else
return NF_ACCEPT;