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Date: Mon, 30 Aug 2021 11:38:52 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org, kuba@...nel.org
Subject: [PATCH net-next 8/8] netfilter: add netfilter hooks to SRv6 data plane
From: Ryoga Saito <contact@...elbtn.com>
This patch introduces netfilter hooks for solving the problem that
conntrack couldn't record both inner flows and outer flows.
This patch also introduces a new sysctl toggle for enabling lightweight
tunnel netfilter hooks.
Signed-off-by: Ryoga Saito <contact@...elbtn.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
.../networking/nf_conntrack-sysctl.rst | 7 ++
include/net/lwtunnel.h | 3 +
include/net/netfilter/nf_hooks_lwtunnel.h | 7 ++
net/core/lwtunnel.c | 3 +
net/ipv6/seg6_iptunnel.c | 75 +++++++++++-
net/ipv6/seg6_local.c | 111 ++++++++++++------
net/netfilter/Makefile | 3 +
net/netfilter/nf_conntrack_standalone.c | 15 +++
net/netfilter/nf_hooks_lwtunnel.c | 53 +++++++++
9 files changed, 241 insertions(+), 36 deletions(-)
create mode 100644 include/net/netfilter/nf_hooks_lwtunnel.h
create mode 100644 net/netfilter/nf_hooks_lwtunnel.c
diff --git a/Documentation/networking/nf_conntrack-sysctl.rst b/Documentation/networking/nf_conntrack-sysctl.rst
index 024d784157c8..34ca762ea56f 100644
--- a/Documentation/networking/nf_conntrack-sysctl.rst
+++ b/Documentation/networking/nf_conntrack-sysctl.rst
@@ -184,6 +184,13 @@ nf_conntrack_gre_timeout_stream - INTEGER (seconds)
This extended timeout will be used in case there is an GRE stream
detected.
+nf_hooks_lwtunnel - BOOLEAN
+ - 0 - disabled (default)
+ - not 0 - enabled
+
+ If this option is enabled, the lightweight tunnel netfilter hooks are
+ enabled. This option cannot be disabled once it is enabled.
+
nf_flowtable_tcp_timeout - INTEGER (seconds)
default 30
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h
index 05cfd6ff6528..6f15e6fa154e 100644
--- a/include/net/lwtunnel.h
+++ b/include/net/lwtunnel.h
@@ -51,6 +51,9 @@ struct lwtunnel_encap_ops {
};
#ifdef CONFIG_LWTUNNEL
+
+DECLARE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled);
+
void lwtstate_free(struct lwtunnel_state *lws);
static inline struct lwtunnel_state *
diff --git a/include/net/netfilter/nf_hooks_lwtunnel.h b/include/net/netfilter/nf_hooks_lwtunnel.h
new file mode 100644
index 000000000000..52e27920f829
--- /dev/null
+++ b/include/net/netfilter/nf_hooks_lwtunnel.h
@@ -0,0 +1,7 @@
+#include <linux/sysctl.h>
+#include <linux/types.h>
+
+#ifdef CONFIG_SYSCTL
+int nf_hooks_lwtunnel_sysctl_handler(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos);
+#endif
diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c
index d0ae987d2de9..2820aca2173a 100644
--- a/net/core/lwtunnel.c
+++ b/net/core/lwtunnel.c
@@ -23,6 +23,9 @@
#include <net/ip6_fib.h>
#include <net/rtnh.h>
+DEFINE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled);
+EXPORT_SYMBOL_GPL(nf_hooks_lwtunnel_enabled);
+
#ifdef CONFIG_MODULES
static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type)
diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c
index 897fa59c47de..6ebc7aa24466 100644
--- a/net/ipv6/seg6_iptunnel.c
+++ b/net/ipv6/seg6_iptunnel.c
@@ -26,6 +26,8 @@
#ifdef CONFIG_IPV6_SEG6_HMAC
#include <net/seg6_hmac.h>
#endif
+#include <net/lwtunnel.h>
+#include <linux/netfilter.h>
static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
{
@@ -295,11 +297,19 @@ static int seg6_do_srh(struct sk_buff *skb)
ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+ nf_reset_ct(skb);
return 0;
}
-static int seg6_input(struct sk_buff *skb)
+static int seg6_input_finish(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
+{
+ return dst_input(skb);
+}
+
+static int seg6_input_core(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct dst_entry *dst = NULL;
@@ -337,10 +347,41 @@ static int seg6_input(struct sk_buff *skb)
if (unlikely(err))
return err;
- return dst_input(skb);
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+ dev_net(skb->dev), NULL, skb, NULL,
+ skb_dst(skb)->dev, seg6_input_finish);
+
+ return seg6_input_finish(dev_net(skb->dev), NULL, skb);
}
-static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+static int seg6_input_nf(struct sk_buff *skb)
+{
+ struct net_device *dev = skb_dst(skb)->dev;
+ struct net *net = dev_net(skb->dev);
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, NULL,
+ skb, NULL, dev, seg6_input_core);
+ case htons(ETH_P_IPV6):
+ return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, NULL,
+ skb, NULL, dev, seg6_input_core);
+ }
+
+ return -EINVAL;
+}
+
+static int seg6_input(struct sk_buff *skb)
+{
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return seg6_input_nf(skb);
+
+ return seg6_input_core(dev_net(skb->dev), NULL, skb);
+}
+
+static int seg6_output_core(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct dst_entry *dst = NULL;
@@ -387,12 +428,40 @@ static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
if (unlikely(err))
goto drop;
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb,
+ NULL, skb_dst(skb)->dev, dst_output);
+
return dst_output(net, sk, skb);
drop:
kfree_skb(skb);
return err;
}
+static int seg6_output_nf(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+ struct net_device *dev = skb_dst(skb)->dev;
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, sk, skb,
+ NULL, dev, seg6_output_core);
+ case htons(ETH_P_IPV6):
+ return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, sk, skb,
+ NULL, dev, seg6_output_core);
+ }
+
+ return -EINVAL;
+}
+
+static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return seg6_output_nf(net, sk, skb);
+
+ return seg6_output_core(net, sk, skb);
+}
+
static int seg6_build_state(struct net *net, struct nlattr *nla,
unsigned int family, const void *cfg,
struct lwtunnel_state **ts,
diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
index 60bf3b877957..ddc8dfcd4e2b 100644
--- a/net/ipv6/seg6_local.c
+++ b/net/ipv6/seg6_local.c
@@ -30,6 +30,8 @@
#include <net/seg6_local.h>
#include <linux/etherdevice.h>
#include <linux/bpf.h>
+#include <net/lwtunnel.h>
+#include <linux/netfilter.h>
#define SEG6_F_ATTR(i) BIT(i)
@@ -413,12 +415,33 @@ static int input_action_end_dx2(struct sk_buff *skb,
return -EINVAL;
}
+static int input_action_end_dx6_finish(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
+{
+ struct dst_entry *orig_dst = skb_dst(skb);
+ struct in6_addr *nhaddr = NULL;
+ struct seg6_local_lwt *slwt;
+
+ slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
+
+ /* The inner packet is not associated to any local interface,
+ * so we do not call netif_rx().
+ *
+ * If slwt->nh6 is set to ::, then lookup the nexthop for the
+ * inner packet's DA. Otherwise, use the specified nexthop.
+ */
+ if (!ipv6_addr_any(&slwt->nh6))
+ nhaddr = &slwt->nh6;
+
+ seg6_lookup_nexthop(skb, nhaddr, 0);
+
+ return dst_input(skb);
+}
+
/* decapsulate and forward to specified nexthop */
static int input_action_end_dx6(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
- struct in6_addr *nhaddr = NULL;
-
/* this function accepts IPv6 encapsulated packets, with either
* an SRH with SL=0, or no SRH.
*/
@@ -429,40 +452,30 @@ static int input_action_end_dx6(struct sk_buff *skb,
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto drop;
- /* The inner packet is not associated to any local interface,
- * so we do not call netif_rx().
- *
- * If slwt->nh6 is set to ::, then lookup the nexthop for the
- * inner packet's DA. Otherwise, use the specified nexthop.
- */
-
- if (!ipv6_addr_any(&slwt->nh6))
- nhaddr = &slwt->nh6;
-
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+ nf_reset_ct(skb);
- seg6_lookup_nexthop(skb, nhaddr, 0);
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
+ dev_net(skb->dev), NULL, skb, NULL,
+ skb_dst(skb)->dev, input_action_end_dx6_finish);
- return dst_input(skb);
+ return input_action_end_dx6_finish(dev_net(skb->dev), NULL, skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
-static int input_action_end_dx4(struct sk_buff *skb,
- struct seg6_local_lwt *slwt)
+static int input_action_end_dx4_finish(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
{
+ struct dst_entry *orig_dst = skb_dst(skb);
+ struct seg6_local_lwt *slwt;
struct iphdr *iph;
__be32 nhaddr;
int err;
- if (!decap_and_validate(skb, IPPROTO_IPIP))
- goto drop;
-
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
- goto drop;
-
- skb->protocol = htons(ETH_P_IP);
+ slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
iph = ip_hdr(skb);
@@ -470,14 +483,34 @@ static int input_action_end_dx4(struct sk_buff *skb,
skb_dst_drop(skb);
- skb_set_transport_header(skb, sizeof(struct iphdr));
-
err = ip_route_input(skb, nhaddr, iph->saddr, 0, skb->dev);
- if (err)
- goto drop;
+ if (err) {
+ kfree_skb(skb);
+ return -EINVAL;
+ }
return dst_input(skb);
+}
+
+static int input_action_end_dx4(struct sk_buff *skb,
+ struct seg6_local_lwt *slwt)
+{
+ if (!decap_and_validate(skb, IPPROTO_IPIP))
+ goto drop;
+
+ if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+ goto drop;
+
+ skb->protocol = htons(ETH_P_IP);
+ skb_set_transport_header(skb, sizeof(struct iphdr));
+ nf_reset_ct(skb);
+
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
+ dev_net(skb->dev), NULL, skb, NULL,
+ skb_dst(skb)->dev, input_action_end_dx4_finish);
+ return input_action_end_dx4_finish(dev_net(skb->dev), NULL, skb);
drop:
kfree_skb(skb);
return -EINVAL;
@@ -645,6 +678,7 @@ static struct sk_buff *end_dt_vrf_core(struct sk_buff *skb,
skb_dst_drop(skb);
skb_set_transport_header(skb, hdrlen);
+ nf_reset_ct(skb);
return end_dt_vrf_rcv(skb, family, vrf);
@@ -1078,7 +1112,8 @@ static void seg6_local_update_counters(struct seg6_local_lwt *slwt,
u64_stats_update_end(&pcounters->syncp);
}
-static int seg6_local_input(struct sk_buff *skb)
+static int seg6_local_input_core(struct net *net, struct sock *sk,
+ struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct seg6_action_desc *desc;
@@ -1086,11 +1121,6 @@ static int seg6_local_input(struct sk_buff *skb)
unsigned int len = skb->len;
int rc;
- if (skb->protocol != htons(ETH_P_IPV6)) {
- kfree_skb(skb);
- return -EINVAL;
- }
-
slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
desc = slwt->desc;
@@ -1104,6 +1134,21 @@ static int seg6_local_input(struct sk_buff *skb)
return rc;
}
+static int seg6_local_input(struct sk_buff *skb)
+{
+ if (skb->protocol != htons(ETH_P_IPV6)) {
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
+ dev_net(skb->dev), NULL, skb, skb->dev, NULL,
+ seg6_local_input_core);
+
+ return seg6_local_input_core(dev_net(skb->dev), NULL, skb);
+}
+
static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = {
[SEG6_LOCAL_ACTION] = { .type = NLA_U32 },
[SEG6_LOCAL_SRH] = { .type = NLA_BINARY },
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 049890e00a3d..aab20e575ecd 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -212,3 +212,6 @@ obj-$(CONFIG_IP_SET) += ipset/
# IPVS
obj-$(CONFIG_IP_VS) += ipvs/
+
+# lwtunnel
+obj-$(CONFIG_LWTUNNEL) += nf_hooks_lwtunnel.o
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index e84b499b7bfa..7e0d956da51d 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -22,6 +22,9 @@
#include <net/netfilter/nf_conntrack_acct.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/nf_conntrack_timestamp.h>
+#ifdef CONFIG_LWTUNNEL
+#include <net/netfilter/nf_hooks_lwtunnel.h>
+#endif
#include <linux/rculist_nulls.h>
static bool enable_hooks __read_mostly;
@@ -612,6 +615,9 @@ enum nf_ct_sysctl_index {
NF_SYSCTL_CT_PROTO_TIMEOUT_GRE,
NF_SYSCTL_CT_PROTO_TIMEOUT_GRE_STREAM,
#endif
+#ifdef CONFIG_LWTUNNEL
+ NF_SYSCTL_CT_LWTUNNEL,
+#endif
__NF_SYSCTL_CT_LAST_SYSCTL,
};
@@ -958,6 +964,15 @@ static struct ctl_table nf_ct_sysctl_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
+#endif
+#ifdef CONFIG_LWTUNNEL
+ [NF_SYSCTL_CT_LWTUNNEL] = {
+ .procname = "nf_hooks_lwtunnel",
+ .data = NULL,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = nf_hooks_lwtunnel_sysctl_handler,
+ },
#endif
{}
};
diff --git a/net/netfilter/nf_hooks_lwtunnel.c b/net/netfilter/nf_hooks_lwtunnel.c
new file mode 100644
index 000000000000..00e89ffd78f6
--- /dev/null
+++ b/net/netfilter/nf_hooks_lwtunnel.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/sysctl.h>
+#include <net/lwtunnel.h>
+#include <net/netfilter/nf_hooks_lwtunnel.h>
+
+static inline int nf_hooks_lwtunnel_get(void)
+{
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+ return 1;
+ else
+ return 0;
+}
+
+static inline int nf_hooks_lwtunnel_set(int enable)
+{
+ if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) {
+ if (!enable)
+ return -EBUSY;
+ } else if (enable) {
+ static_branch_enable(&nf_hooks_lwtunnel_enabled);
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_SYSCTL
+int nf_hooks_lwtunnel_sysctl_handler(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ int proc_nf_hooks_lwtunnel_enabled = 0;
+ struct ctl_table tmp = {
+ .procname = table->procname,
+ .data = &proc_nf_hooks_lwtunnel_enabled,
+ .maxlen = sizeof(int),
+ .mode = table->mode,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ };
+ int ret;
+
+ if (!write)
+ proc_nf_hooks_lwtunnel_enabled = nf_hooks_lwtunnel_get();
+
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+
+ if (write && ret == 0)
+ ret = nf_hooks_lwtunnel_set(proc_nf_hooks_lwtunnel_enabled);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nf_hooks_lwtunnel_sysctl_handler);
+#endif /* CONFIG_SYSCTL */
--
2.20.1
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