Extracted from the xtables TEE target. This creates two new modules for IPv4
and IPv6 that are shared between the TEE target and the new nf_tables dup
expressions.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/net/netfilter/ipv4/nf_dup_ipv4.h | 7 ++
include/net/netfilter/ipv6/nf_dup_ipv6.h | 7 ++
net/ipv4/netfilter/Kconfig | 6 ++
net/ipv4/netfilter/Makefile | 2 +
net/ipv4/netfilter/nf_dup_ipv4.c | 121 ++++++++++++++++++++++
net/ipv6/netfilter/Kconfig | 6 ++
net/ipv6/netfilter/Makefile | 2 +
net/ipv6/netfilter/nf_dup_ipv6.c | 97 ++++++++++++++++++
net/netfilter/Kconfig | 2 +
net/netfilter/xt_TEE.c | 162 ++----------------------------
10 files changed, 256 insertions(+), 156 deletions(-)
create mode 100644 include/net/netfilter/ipv4/nf_dup_ipv4.h
create mode 100644 include/net/netfilter/ipv6/nf_dup_ipv6.h
create mode 100644 net/ipv4/netfilter/nf_dup_ipv4.c
create mode 100644 net/ipv6/netfilter/nf_dup_ipv6.c
diff --git a/include/net/netfilter/ipv4/nf_dup_ipv4.h b/include/net/netfilter/ipv4/nf_dup_ipv4.h
new file mode 100644
index 0000000..dc54e30
--- /dev/null
+++ b/include/net/netfilter/ipv4/nf_dup_ipv4.h
@@ -0,0 +1,7 @@
+#ifndef _NF_DUP_IPV4_H_
+#define _NF_DUP_IPV4_H_
+
+unsigned int nf_dup_ipv4(struct sk_buff *skb, unsigned int hooknum,
+ const struct in_addr *gw, int oif);
+
+#endif /* _NF_DUP_IPV4_H_ */
diff --git a/include/net/netfilter/ipv6/nf_dup_ipv6.h b/include/net/netfilter/ipv6/nf_dup_ipv6.h
new file mode 100644
index 0000000..37b598a
--- /dev/null
+++ b/include/net/netfilter/ipv6/nf_dup_ipv6.h
@@ -0,0 +1,7 @@
+#ifndef _NF_DUP_IPV6_H_
+#define _NF_DUP_IPV6_H_
+
+unsigned int nf_dup_ipv6(struct sk_buff *skb, unsigned int hooknum,
+ const struct in6_addr *gw, int oif);
+
+#endif /* _NF_DUP_IPV6_H_ */
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 2199a5d..0142ea2 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -67,6 +67,12 @@ config NF_TABLES_ARP
endif # NF_TABLES
+config NF_DUP_IPV4
+ tristate "Netfilter IPv4 packet duplication to alternate destination"
+ help
+ This option enables the nf_dup_ipv4 core, which duplicates an IPv4
+ packet to be rerouted to another destination.
+
config NF_LOG_ARP
tristate "ARP packet logging"
default m if NETFILTER_ADVANCED=n
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 7fe6c70..9136ffc 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -70,3 +70,5 @@ obj-$(CONFIG_IP_NF_ARP_MANGLE) += arpt_mangle.o
# just filtering instance of ARP tables for now
obj-$(CONFIG_IP_NF_ARPFILTER) += arptable_filter.o
+
+obj-$(CONFIG_NF_DUP_IPV4) += nf_dup_ipv4.o
diff --git a/net/ipv4/netfilter/nf_dup_ipv4.c b/net/ipv4/netfilter/nf_dup_ipv4.c
new file mode 100644
index 0000000..feba24a
--- /dev/null
+++ b/net/ipv4/netfilter/nf_dup_ipv4.c
@@ -0,0 +1,121 @@
+/*
+ * (C) 2007 by Sebastian Claßen <sebastian.classen@xxxxxxxxxx>
+ * (C) 2007-2010 by Jan Engelhardt <jengelh@xxxxxxxxxx>
+ *
+ * Extracted from xt_TEE.c
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later, as
+ * published by the Free Software Foundation.
+ */
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/route.h>
+#include <linux/skbuff.h>
+#include <net/checksum.h>
+#include <net/icmp.h>
+#include <net/ip.h>
+#include <net/route.h>
+#include <net/netfilter/ipv4/nf_dup_ipv4.h>
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#include <net/netfilter/nf_conntrack.h>
+#endif
+
+static struct net *pick_net(struct sk_buff *skb)
+{
+#ifdef CONFIG_NET_NS
+ const struct dst_entry *dst;
+
+ if (skb->dev != NULL)
+ return dev_net(skb->dev);
+ dst = skb_dst(skb);
+ if (dst != NULL && dst->dev != NULL)
+ return dev_net(dst->dev);
+#endif
+ return &init_net;
+}
+
+static bool nf_dup_ipv4_route(struct sk_buff *skb, const struct in_addr *gw,
+ int oif)
+{
+ const struct iphdr *iph = ip_hdr(skb);
+ struct net *net = pick_net(skb);
+ struct rtable *rt;
+ struct flowi4 fl4;
+
+ memset(&fl4, 0, sizeof(fl4));
+ if (oif != -1)
+ fl4.flowi4_oif = oif;
+
+ fl4.daddr = gw->s_addr;
+ fl4.flowi4_tos = RT_TOS(iph->tos);
+ fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
+ fl4.flowi4_flags = FLOWI_FLAG_KNOWN_NH;
+ rt = ip_route_output_key(net, &fl4);
+ if (IS_ERR(rt))
+ return false;
+
+ skb_dst_drop(skb);
+ skb_dst_set(skb, &rt->dst);
+ skb->dev = rt->dst.dev;
+ skb->protocol = htons(ETH_P_IP);
+
+ return true;
+}
+
+unsigned int nf_dup_ipv4(struct sk_buff *skb, unsigned int hooknum,
+ const struct in_addr *gw, int oif)
+{
+ struct iphdr *iph;
+
+ if (__this_cpu_read(nf_skb_duplicated))
+ return XT_CONTINUE;
+ /*
+ * Copy the skb, and route the copy. Will later return %XT_CONTINUE for
+ * the original skb, which should continue on its way as if nothing has
+ * happened. The copy should be independently delivered to the gateway.
+ */
+ skb = pskb_copy(skb, GFP_ATOMIC);
+ if (skb == NULL)
+ return XT_CONTINUE;
+
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+ /* Avoid counting cloned packets towards the original connection. */
+ nf_conntrack_put(skb->nfct);
+ skb->nfct = &nf_ct_untracked_get()->ct_general;
+ skb->nfctinfo = IP_CT_NEW;
+ nf_conntrack_get(skb->nfct);
+#endif
+ /*
+ * If we are in PREROUTING/INPUT, the checksum must be recalculated
+ * since the length could have changed as a result of defragmentation.
+ *
+ * We also decrease the TTL to mitigate potential loops between two
+ * hosts.
+ *
+ * Set %IP_DF so that the original source is notified of a potentially
+ * decreased MTU on the clone route. IPv6 does this too.
+ */
+ iph = ip_hdr(skb);
+ iph->frag_off |= htons(IP_DF);
+ if (hooknum == NF_INET_PRE_ROUTING ||
+ hooknum == NF_INET_LOCAL_IN)
+ --iph->ttl;
+ ip_send_check(iph);
+
+ if (nf_dup_ipv4_route(skb, gw, oif)) {
+ __this_cpu_write(nf_skb_duplicated, true);
+ ip_local_out(skb);
+ __this_cpu_write(nf_skb_duplicated, false);
+ } else {
+ kfree_skb(skb);
+ }
+ return XT_CONTINUE;
+}
+EXPORT_SYMBOL_GPL(nf_dup_ipv4);
+
+MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@xxxxxxxxxx>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@xxxxxxxxxx>");
+MODULE_DESCRIPTION("nf_dup_ipv4: Duplicate IPv4 packet");
+MODULE_LICENSE("GPL");
diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index b552cf0..298daf3 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -50,6 +50,12 @@ config NFT_REJECT_IPV6
endif # NF_TABLES_IPV6
endif # NF_TABLES
+config NF_DUP_IPV6
+ tristate "Netfilter IPv6 packet duplication to alternate destination"
+ help
+ This option enables the nf_dup_ipv6 core, which duplicates an IPv6
+ packet to be rerouted to another destination.
+
config NF_REJECT_IPV6
tristate "IPv6 packet rejection"
default m if NETFILTER_ADVANCED=n
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index c36e0a5..dc6c732 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -30,6 +30,8 @@ obj-$(CONFIG_NF_LOG_IPV6) += nf_log_ipv6.o
# reject
obj-$(CONFIG_NF_REJECT_IPV6) += nf_reject_ipv6.o
+obj-$(CONFIG_NF_DUP_IPV6) += nf_dup_ipv6.o
+
# nf_tables
obj-$(CONFIG_NF_TABLES_IPV6) += nf_tables_ipv6.o
obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV6) += nft_chain_route_ipv6.o
diff --git a/net/ipv6/netfilter/nf_dup_ipv6.c b/net/ipv6/netfilter/nf_dup_ipv6.c
new file mode 100644
index 0000000..ca7e867
--- /dev/null
+++ b/net/ipv6/netfilter/nf_dup_ipv6.c
@@ -0,0 +1,97 @@
+/*
+ * (C) 2007 by Sebastian Claßen <sebastian.classen@xxxxxxxxxx>
+ * (C) 2007-2010 by Jan Engelhardt <jengelh@xxxxxxxxxx>
+ *
+ * Extracted from xt_TEE.c
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later, as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/skbuff.h>
+#include <net/ipv6.h>
+#include <net/ip6_route.h>
+#include <net/netfilter/ipv6/nf_dup_ipv6.h>
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#include <net/netfilter/nf_conntrack.h>
+#endif
+
+static struct net *pick_net(struct sk_buff *skb)
+{
+#ifdef CONFIG_NET_NS
+ const struct dst_entry *dst;
+
+ if (skb->dev != NULL)
+ return dev_net(skb->dev);
+ dst = skb_dst(skb);
+ if (dst != NULL && dst->dev != NULL)
+ return dev_net(dst->dev);
+#endif
+ return &init_net;
+}
+
+static bool nf_dup_ipv6_route(struct sk_buff *skb, const struct in6_addr *gw,
+ int oif)
+{
+ const struct ipv6hdr *iph = ipv6_hdr(skb);
+ struct net *net = pick_net(skb);
+ struct dst_entry *dst;
+ struct flowi6 fl6;
+
+ memset(&fl6, 0, sizeof(fl6));
+ if (oif != -1)
+ fl6.flowi6_oif = oif;
+
+ fl6.daddr = *gw;
+ fl6.flowlabel = ((iph->flow_lbl[0] & 0xF) << 16) |
+ (iph->flow_lbl[1] << 8) | iph->flow_lbl[2];
+ dst = ip6_route_output(net, NULL, &fl6);
+ if (dst->error) {
+ dst_release(dst);
+ return false;
+ }
+ skb_dst_drop(skb);
+ skb_dst_set(skb, dst);
+ skb->dev = dst->dev;
+ skb->protocol = htons(ETH_P_IPV6);
+
+ return true;
+}
+
+unsigned int nf_dup_ipv6(struct sk_buff *skb, unsigned int hooknum,
+ const struct in6_addr *gw, int oif)
+{
+ if (__this_cpu_read(nf_skb_duplicated))
+ return XT_CONTINUE;
+ skb = pskb_copy(skb, GFP_ATOMIC);
+ if (skb == NULL)
+ return XT_CONTINUE;
+
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+ nf_conntrack_put(skb->nfct);
+ skb->nfct = &nf_ct_untracked_get()->ct_general;
+ skb->nfctinfo = IP_CT_NEW;
+ nf_conntrack_get(skb->nfct);
+#endif
+ if (hooknum == NF_INET_PRE_ROUTING ||
+ hooknum == NF_INET_LOCAL_IN) {
+ struct ipv6hdr *iph = ipv6_hdr(skb);
+ --iph->hop_limit;
+ }
+ if (nf_dup_ipv6_route(skb, gw, oif)) {
+ __this_cpu_write(nf_skb_duplicated, true);
+ ip6_local_out(skb);
+ __this_cpu_write(nf_skb_duplicated, false);
+ } else {
+ kfree_skb(skb);
+ }
+ return XT_CONTINUE;
+}
+EXPORT_SYMBOL_GPL(nf_dup_ipv6);
+
+MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@xxxxxxxxxx>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@xxxxxxxxxx>");
+MODULE_DESCRIPTION("nf_dup_ipv6: IPv6 packet duplication");
+MODULE_LICENSE("GPL");
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 6eae69a..3e1b4ab 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -867,6 +867,8 @@ config NETFILTER_XT_TARGET_TEE
depends on NETFILTER_ADVANCED
depends on IPV6 || IPV6=n
depends on !NF_CONNTRACK || NF_CONNTRACK
+ select NF_DUP_IPV4
+ select NF_DUP_IPV6 if IP6_NF_IPTABLES
---help---
This option adds a "TEE" target with which a packet can be cloned and
this clone be rerouted to another nexthop.
diff --git a/net/netfilter/xt_TEE.c b/net/netfilter/xt_TEE.c
index 0ed9fb6..e86202b 100644
--- a/net/netfilter/xt_TEE.c
+++ b/net/netfilter/xt_TEE.c
@@ -10,23 +10,14 @@
* modify it under the terms of the GNU General Public License
* version 2 or later, as published by the Free Software Foundation.
*/
-#include <linux/ip.h>
#include <linux/module.h>
-#include <linux/percpu.h>
-#include <linux/route.h>
#include <linux/skbuff.h>
-#include <linux/notifier.h>
-#include <net/checksum.h>
-#include <net/icmp.h>
-#include <net/ip.h>
-#include <net/ipv6.h>
-#include <net/ip6_route.h>
-#include <net/route.h>
+#include <linux/route.h>
#include <linux/netfilter/x_tables.h>
+#include <net/route.h>
+#include <net/netfilter/ipv4/nf_dup_ipv4.h>
+#include <net/netfilter/ipv6/nf_dup_ipv6.h>
#include <linux/netfilter/xt_TEE.h>
-#if IS_ENABLED(CONFIG_NF_CONNTRACK)
-#include <net/netfilter/nf_conntrack.h>
-#endif
struct xt_tee_priv {
struct notifier_block notifier;
@@ -36,162 +27,21 @@ struct xt_tee_priv {
static const union nf_inet_addr tee_zero_address;
-static struct net *pick_net(struct sk_buff *skb)
-{
-#ifdef CONFIG_NET_NS
- const struct dst_entry *dst;
-
- if (skb->dev != NULL)
- return dev_net(skb->dev);
- dst = skb_dst(skb);
- if (dst != NULL && dst->dev != NULL)
- return dev_net(dst->dev);
-#endif
- return &init_net;
-}
-
-static bool
-tee_tg_route4(struct sk_buff *skb, const struct xt_tee_tginfo *info)
-{
- const struct iphdr *iph = ip_hdr(skb);
- struct net *net = pick_net(skb);
- struct rtable *rt;
- struct flowi4 fl4;
-
- memset(&fl4, 0, sizeof(fl4));
- if (info->priv) {
- if (info->priv->oif == -1)
- return false;
- fl4.flowi4_oif = info->priv->oif;
- }
- fl4.daddr = info->gw.ip;
- fl4.flowi4_tos = RT_TOS(iph->tos);
- fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
- fl4.flowi4_flags = FLOWI_FLAG_KNOWN_NH;
- rt = ip_route_output_key(net, &fl4);
- if (IS_ERR(rt))
- return false;
-
- skb_dst_drop(skb);
- skb_dst_set(skb, &rt->dst);
- skb->dev = rt->dst.dev;
- skb->protocol = htons(ETH_P_IP);
- return true;
-}
-
static unsigned int
tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_tee_tginfo *info = par->targinfo;
- struct iphdr *iph;
-
- if (__this_cpu_read(nf_skb_duplicated))
- return XT_CONTINUE;
- /*
- * Copy the skb, and route the copy. Will later return %XT_CONTINUE for
- * the original skb, which should continue on its way as if nothing has
- * happened. The copy should be independently delivered to the TEE
- * --gateway.
- */
- skb = pskb_copy(skb, GFP_ATOMIC);
- if (skb == NULL)
- return XT_CONTINUE;
-
-#if IS_ENABLED(CONFIG_NF_CONNTRACK)
- /* Avoid counting cloned packets towards the original connection. */
- nf_conntrack_put(skb->nfct);
- skb->nfct = &nf_ct_untracked_get()->ct_general;
- skb->nfctinfo = IP_CT_NEW;
- nf_conntrack_get(skb->nfct);
-#endif
- /*
- * If we are in PREROUTING/INPUT, the checksum must be recalculated
- * since the length could have changed as a result of defragmentation.
- *
- * We also decrease the TTL to mitigate potential TEE loops
- * between two hosts.
- *
- * Set %IP_DF so that the original source is notified of a potentially
- * decreased MTU on the clone route. IPv6 does this too.
- */
- iph = ip_hdr(skb);
- iph->frag_off |= htons(IP_DF);
- if (par->hooknum == NF_INET_PRE_ROUTING ||
- par->hooknum == NF_INET_LOCAL_IN)
- --iph->ttl;
- ip_send_check(iph);
- if (tee_tg_route4(skb, info)) {
- __this_cpu_write(nf_skb_duplicated, true);
- ip_local_out(skb);
- __this_cpu_write(nf_skb_duplicated, false);
- } else {
- kfree_skb(skb);
- }
- return XT_CONTINUE;
+ return nf_dup_ipv4(skb, par->hooknum, &info->gw.in, info->priv->oif);
}
#if IS_ENABLED(CONFIG_IPV6)
-static bool
-tee_tg_route6(struct sk_buff *skb, const struct xt_tee_tginfo *info)
-{
- const struct ipv6hdr *iph = ipv6_hdr(skb);
- struct net *net = pick_net(skb);
- struct dst_entry *dst;
- struct flowi6 fl6;
-
- memset(&fl6, 0, sizeof(fl6));
- if (info->priv) {
- if (info->priv->oif == -1)
- return false;
- fl6.flowi6_oif = info->priv->oif;
- }
- fl6.daddr = info->gw.in6;
- fl6.flowlabel = ((iph->flow_lbl[0] & 0xF) << 16) |
- (iph->flow_lbl[1] << 8) | iph->flow_lbl[2];
- fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
- dst = ip6_route_output(net, NULL, &fl6);
- if (dst->error) {
- dst_release(dst);
- return false;
- }
- skb_dst_drop(skb);
- skb_dst_set(skb, dst);
- skb->dev = dst->dev;
- skb->protocol = htons(ETH_P_IPV6);
- return true;
-}
-
static unsigned int
tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_tee_tginfo *info = par->targinfo;
- if (__this_cpu_read(nf_skb_duplicated))
- return XT_CONTINUE;
- skb = pskb_copy(skb, GFP_ATOMIC);
- if (skb == NULL)
- return XT_CONTINUE;
-
-#if IS_ENABLED(CONFIG_NF_CONNTRACK)
- nf_conntrack_put(skb->nfct);
- skb->nfct = &nf_ct_untracked_get()->ct_general;
- skb->nfctinfo = IP_CT_NEW;
- nf_conntrack_get(skb->nfct);
-#endif
- if (par->hooknum == NF_INET_PRE_ROUTING ||
- par->hooknum == NF_INET_LOCAL_IN) {
- struct ipv6hdr *iph = ipv6_hdr(skb);
- --iph->hop_limit;
- }
- if (tee_tg_route6(skb, info)) {
- __this_cpu_write(nf_skb_duplicated, true);
- ip6_local_out(skb);
- __this_cpu_write(nf_skb_duplicated, false);
- } else {
- kfree_skb(skb);
- }
- return XT_CONTINUE;
+ return nf_dup_ipv6(skb, par->hooknum, &info->gw.in6, info->priv->oif);
}
#endif
--
1.7.10.4
--
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