diff mbox series

[2/3] xfrm: Support GRO for IPv4 ESP in UDP encapsulation.

Message ID 2527cc66bfbcf70bcfd64efdf8ff79d60199827e.1674156645.git.antony.antony@secunet.com (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series [1/3] xfrm: Use the XFRM_GRO to indicate a GRO call on input. | expand

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netdev/header_inline success No static functions without inline keyword in header files
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Commit Message

Antony Antony Jan. 19, 2023, 7:33 p.m. UTC 
From: Steffen Klassert <steffen.klassert@secunet.com>

This patch enables the GRO codepath for IPv4 ESP in UDP encapsulated
packets. Decapsulation happens at L2 and saves a full round through
the stack for each packet. This is also needed to support HW offload
for ESP in UDP encapsulation.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Co-developed-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
---
 include/net/gro.h       |  2 +-
 include/net/xfrm.h      |  4 ++
 net/ipv4/esp4_offload.c | 11 ++++-
 net/ipv4/udp.c          |  4 +-
 net/ipv4/xfrm4_input.c  | 99 +++++++++++++++++++++++++++++++++--------
 5 files changed, 99 insertions(+), 21 deletions(-)

Comments

Eyal Birger Jan. 20, 2023, 11:04 a.m. UTC | #1 
Hi,

On Thu, Jan 19, 2023 at 10:00 PM Antony Antony
<antony.antony@secunet.com> wrote:
>
> From: Steffen Klassert <steffen.klassert@secunet.com>
>
> This patch enables the GRO codepath for IPv4 ESP in UDP encapsulated
> packets. Decapsulation happens at L2 and saves a full round through
> the stack for each packet. This is also needed to support HW offload
> for ESP in UDP encapsulation.
>
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
> Co-developed-by: Antony Antony <antony.antony@secunet.com>
> Signed-off-by: Antony Antony <antony.antony@secunet.com>
> ---
>  include/net/gro.h       |  2 +-
>  include/net/xfrm.h      |  4 ++
>  net/ipv4/esp4_offload.c | 11 ++++-
>  net/ipv4/udp.c          |  4 +-
>  net/ipv4/xfrm4_input.c  | 99 +++++++++++++++++++++++++++++++++--------
>  5 files changed, 99 insertions(+), 21 deletions(-)
>
> diff --git a/include/net/gro.h b/include/net/gro.h
> index a4fab706240d..41c12c5d1ea1 100644
> --- a/include/net/gro.h
> +++ b/include/net/gro.h
> @@ -29,7 +29,7 @@ struct napi_gro_cb {
>         /* Number of segments aggregated. */
>         u16     count;
>
> -       /* Used in ipv6_gro_receive() and foo-over-udp */
> +       /* Used in ipv6_gro_receive() and foo-over-udp and esp-in-udp */
>         u16     proto;
>
>         /* jiffies when first packet was created/queued */
> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
> index 3e1f70e8e424..74dba98fbf2c 100644
> --- a/include/net/xfrm.h
> +++ b/include/net/xfrm.h
> @@ -1666,6 +1666,8 @@ void xfrm_local_error(struct sk_buff *skb, int mtu);
>  int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb);
>  int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
>                     int encap_type);
> +struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
> +                                       struct sk_buff *skb);
>  int xfrm4_transport_finish(struct sk_buff *skb, int async);
>  int xfrm4_rcv(struct sk_buff *skb);
>
> @@ -1706,6 +1708,8 @@ int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb);
>  void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu);
>  int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);
>  int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);
> +struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
> +                                       struct sk_buff *skb);
>  int xfrm_user_policy(struct sock *sk, int optname, sockptr_t optval,
>                      int optlen);
>  #else
> diff --git a/net/ipv4/esp4_offload.c b/net/ipv4/esp4_offload.c
> index 77bb01032667..8769bb669fdd 100644
> --- a/net/ipv4/esp4_offload.c
> +++ b/net/ipv4/esp4_offload.c
> @@ -32,6 +32,7 @@ static struct sk_buff *esp4_gro_receive(struct list_head *head,
>         int offset = skb_gro_offset(skb);
>         struct xfrm_offload *xo;
>         struct xfrm_state *x;
> +       int encap_type = 0;
>         __be32 seq;
>         __be32 spi;
>
> @@ -69,6 +70,14 @@ static struct sk_buff *esp4_gro_receive(struct list_head *head,
>
>         xo->flags |= XFRM_GRO;
>
> +       if (NAPI_GRO_CB(skb)->proto == IPPROTO_UDP && skb->sk &&
> +           (udp_sk(skb->sk)->encap_type == UDP_ENCAP_ESPINUDP ||
> +            udp_sk(skb->sk)->encap_type == UDP_ENCAP_ESPINUDP_NON_IKE)) {
> +               encap_type = udp_sk(skb->sk)->encap_type;
> +               sock_put(skb->sk);
> +               skb->sk = NULL;
> +       }
> +
>         XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
>         XFRM_SPI_SKB_CB(skb)->family = AF_INET;
>         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
> @@ -76,7 +85,7 @@ static struct sk_buff *esp4_gro_receive(struct list_head *head,
>
>         /* We don't need to handle errors from xfrm_input, it does all
>          * the error handling and frees the resources on error. */
> -       xfrm_input(skb, IPPROTO_ESP, spi, 0);
> +       xfrm_input(skb, IPPROTO_ESP, spi, encap_type);
>
>         return ERR_PTR(-EINPROGRESS);
>  out_reset:
> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> index 9592fe3e444a..6a30d0210c4e 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -2729,9 +2729,11 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
>  #if IS_ENABLED(CONFIG_IPV6)
>                         if (sk->sk_family == AF_INET6)
>                                 up->encap_rcv = ipv6_stub->xfrm6_udp_encap_rcv;
> -                       else
>  #endif
> +                       if (sk->sk_family == AF_INET) {
>                                 up->encap_rcv = xfrm4_udp_encap_rcv;
> +                               up->gro_receive = xfrm4_gro_udp_encap_rcv;
> +                       }
>  #endif
>                         fallthrough;
>                 case UDP_ENCAP_L2TPINUDP:
> diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
> index ad2afeef4f10..768d12491a48 100644
> --- a/net/ipv4/xfrm4_input.c
> +++ b/net/ipv4/xfrm4_input.c
> @@ -17,6 +17,8 @@
>  #include <linux/netfilter_ipv4.h>
>  #include <net/ip.h>
>  #include <net/xfrm.h>
> +#include <net/protocol.h>
> +#include <net/gro.h>
>
>  static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
>                                    struct sk_buff *skb)
> @@ -72,14 +74,7 @@ int xfrm4_transport_finish(struct sk_buff *skb, int async)
>         return 0;
>  }
>
> -/* If it's a keepalive packet, then just eat it.
> - * If it's an encapsulated packet, then pass it to the
> - * IPsec xfrm input.
> - * Returns 0 if skb passed to xfrm or was dropped.
> - * Returns >0 if skb should be passed to UDP.
> - * Returns <0 if skb should be resubmitted (-ret is protocol)
> - */
> -int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
> +static int __xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull)
>  {
>         struct udp_sock *up = udp_sk(sk);
>         struct udphdr *uh;
> @@ -110,7 +105,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
>         case UDP_ENCAP_ESPINUDP:
>                 /* Check if this is a keepalive packet.  If so, eat it. */
>                 if (len == 1 && udpdata[0] == 0xff) {
> -                       goto drop;
> +                       return -EINVAL;
>                 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
>                         /* ESP Packet without Non-ESP header */
>                         len = sizeof(struct udphdr);
> @@ -121,7 +116,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
>         case UDP_ENCAP_ESPINUDP_NON_IKE:
>                 /* Check if this is a keepalive packet.  If so, eat it. */
>                 if (len == 1 && udpdata[0] == 0xff) {
> -                       goto drop;
> +                       return -EINVAL;
>                 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
>                            udpdata32[0] == 0 && udpdata32[1] == 0) {
>
> @@ -139,7 +134,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
>          * protocol to ESP, and then call into the transform receiver.
>          */
>         if (skb_unclone(skb, GFP_ATOMIC))
> -               goto drop;
> +               return -EINVAL;
>
>         /* Now we can update and verify the packet length... */
>         iph = ip_hdr(skb);
> @@ -147,24 +142,92 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
>         iph->tot_len = htons(ntohs(iph->tot_len) - len);
>         if (skb->len < iphlen + len) {
>                 /* packet is too small!?! */
> -               goto drop;
> +               return -EINVAL;
>         }
>
>         /* pull the data buffer up to the ESP header and set the
>          * transport header to point to ESP.  Keep UDP on the stack
>          * for later.
>          */
> -       __skb_pull(skb, len);
> -       skb_reset_transport_header(skb);
> +       if (pull) {
> +               __skb_pull(skb, len);
> +               skb_reset_transport_header(skb);
> +       } else {
> +               skb_set_transport_header(skb, len);
> +       }
>
>         /* process ESP */
> -       return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
> -
> -drop:
> -       kfree_skb(skb);
>         return 0;
>  }
>
> +/* If it's a keepalive packet, then just eat it.
> + * If it's an encapsulated packet, then pass it to the
> + * IPsec xfrm input.
> + * Returns 0 if skb passed to xfrm or was dropped.
> + * Returns >0 if skb should be passed to UDP.
> + * Returns <0 if skb should be resubmitted (-ret is protocol)
> + */
> +int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
> +{
> +       int ret;
> +
> +       ret = __xfrm4_udp_encap_rcv(sk, skb, true);
> +       if (!ret)
> +               return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0,
> +                                      udp_sk(sk)->encap_type);
> +
> +       if (ret < 0) {
> +               kfree_skb(skb);
> +               return 0;
> +       }
> +
> +       return ret;
> +}
> +
> +struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
> +                                       struct sk_buff *skb)
> +{
> +       int offset = skb_gro_offset(skb);
> +       const struct net_offload *ops;
> +       struct sk_buff *pp = NULL;
> +       int ret;
> +
> +       offset = offset - sizeof(struct udphdr);
> +
> +       if (!pskb_pull(skb, offset))
> +               return NULL;
> +
> +       if (!refcount_inc_not_zero(&sk->sk_refcnt))
> +               return NULL;
> +

Isn't a push needed in case of failure above?

> +       rcu_read_lock();
> +       ops = rcu_dereference(inet_offloads[IPPROTO_ESP]);
> +       if (!ops || !ops->callbacks.gro_receive)
> +               goto out;
> +
> +       ret = __xfrm4_udp_encap_rcv(sk, skb, false);
> +       if (ret)
> +               goto out;
> +
> +       skb->sk = sk;

Don't you need something like skb_set_owner_sk_safe() so the
destructor is also set?

> +       skb_push(skb, offset);
> +       NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
> +
> +       pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
> +       rcu_read_unlock();
> +
> +       return pp;
> +
> +out:
> +       rcu_read_unlock();
> +       sock_put(sk);
> +       skb_push(skb, offset);
> +       NAPI_GRO_CB(skb)->same_flow = 0;
> +       NAPI_GRO_CB(skb)->flush = 1;
> +
> +       return NULL;
> +}
> +
>  int xfrm4_rcv(struct sk_buff *skb)
>  {
>         return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
> --
> 2.30.2
>

Eyal.
diff mbox series

Patch

diff --git a/include/net/gro.h b/include/net/gro.h
index a4fab706240d..41c12c5d1ea1 100644
--- a/include/net/gro.h
+++ b/include/net/gro.h
@@ -29,7 +29,7 @@  struct napi_gro_cb {
 	/* Number of segments aggregated. */
 	u16	count;
 
-	/* Used in ipv6_gro_receive() and foo-over-udp */
+	/* Used in ipv6_gro_receive() and foo-over-udp and esp-in-udp */
 	u16	proto;
 
 	/* jiffies when first packet was created/queued */
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 3e1f70e8e424..74dba98fbf2c 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1666,6 +1666,8 @@  void xfrm_local_error(struct sk_buff *skb, int mtu);
 int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb);
 int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
 		    int encap_type);
+struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
+					struct sk_buff *skb);
 int xfrm4_transport_finish(struct sk_buff *skb, int async);
 int xfrm4_rcv(struct sk_buff *skb);
 
@@ -1706,6 +1708,8 @@  int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu);
 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);
 int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);
+struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
+					struct sk_buff *skb);
 int xfrm_user_policy(struct sock *sk, int optname, sockptr_t optval,
 		     int optlen);
 #else
diff --git a/net/ipv4/esp4_offload.c b/net/ipv4/esp4_offload.c
index 77bb01032667..8769bb669fdd 100644
--- a/net/ipv4/esp4_offload.c
+++ b/net/ipv4/esp4_offload.c
@@ -32,6 +32,7 @@  static struct sk_buff *esp4_gro_receive(struct list_head *head,
 	int offset = skb_gro_offset(skb);
 	struct xfrm_offload *xo;
 	struct xfrm_state *x;
+	int encap_type = 0;
 	__be32 seq;
 	__be32 spi;
 
@@ -69,6 +70,14 @@  static struct sk_buff *esp4_gro_receive(struct list_head *head,
 
 	xo->flags |= XFRM_GRO;
 
+	if (NAPI_GRO_CB(skb)->proto == IPPROTO_UDP && skb->sk &&
+	    (udp_sk(skb->sk)->encap_type == UDP_ENCAP_ESPINUDP ||
+	     udp_sk(skb->sk)->encap_type == UDP_ENCAP_ESPINUDP_NON_IKE)) {
+		encap_type = udp_sk(skb->sk)->encap_type;
+		sock_put(skb->sk);
+		skb->sk = NULL;
+	}
+
 	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
 	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
 	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
@@ -76,7 +85,7 @@  static struct sk_buff *esp4_gro_receive(struct list_head *head,
 
 	/* We don't need to handle errors from xfrm_input, it does all
 	 * the error handling and frees the resources on error. */
-	xfrm_input(skb, IPPROTO_ESP, spi, 0);
+	xfrm_input(skb, IPPROTO_ESP, spi, encap_type);
 
 	return ERR_PTR(-EINPROGRESS);
 out_reset:
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 9592fe3e444a..6a30d0210c4e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2729,9 +2729,11 @@  int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 #if IS_ENABLED(CONFIG_IPV6)
 			if (sk->sk_family == AF_INET6)
 				up->encap_rcv = ipv6_stub->xfrm6_udp_encap_rcv;
-			else
 #endif
+			if (sk->sk_family == AF_INET) {
 				up->encap_rcv = xfrm4_udp_encap_rcv;
+				up->gro_receive = xfrm4_gro_udp_encap_rcv;
+			}
 #endif
 			fallthrough;
 		case UDP_ENCAP_L2TPINUDP:
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index ad2afeef4f10..768d12491a48 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -17,6 +17,8 @@ 
 #include <linux/netfilter_ipv4.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
+#include <net/protocol.h>
+#include <net/gro.h>
 
 static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
 				   struct sk_buff *skb)
@@ -72,14 +74,7 @@  int xfrm4_transport_finish(struct sk_buff *skb, int async)
 	return 0;
 }
 
-/* If it's a keepalive packet, then just eat it.
- * If it's an encapsulated packet, then pass it to the
- * IPsec xfrm input.
- * Returns 0 if skb passed to xfrm or was dropped.
- * Returns >0 if skb should be passed to UDP.
- * Returns <0 if skb should be resubmitted (-ret is protocol)
- */
-int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
+static int __xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull)
 {
 	struct udp_sock *up = udp_sk(sk);
 	struct udphdr *uh;
@@ -110,7 +105,7 @@  int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	case UDP_ENCAP_ESPINUDP:
 		/* Check if this is a keepalive packet.  If so, eat it. */
 		if (len == 1 && udpdata[0] == 0xff) {
-			goto drop;
+			return -EINVAL;
 		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
 			/* ESP Packet without Non-ESP header */
 			len = sizeof(struct udphdr);
@@ -121,7 +116,7 @@  int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	case UDP_ENCAP_ESPINUDP_NON_IKE:
 		/* Check if this is a keepalive packet.  If so, eat it. */
 		if (len == 1 && udpdata[0] == 0xff) {
-			goto drop;
+			return -EINVAL;
 		} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
 			   udpdata32[0] == 0 && udpdata32[1] == 0) {
 
@@ -139,7 +134,7 @@  int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	 * protocol to ESP, and then call into the transform receiver.
 	 */
 	if (skb_unclone(skb, GFP_ATOMIC))
-		goto drop;
+		return -EINVAL;
 
 	/* Now we can update and verify the packet length... */
 	iph = ip_hdr(skb);
@@ -147,24 +142,92 @@  int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 	iph->tot_len = htons(ntohs(iph->tot_len) - len);
 	if (skb->len < iphlen + len) {
 		/* packet is too small!?! */
-		goto drop;
+		return -EINVAL;
 	}
 
 	/* pull the data buffer up to the ESP header and set the
 	 * transport header to point to ESP.  Keep UDP on the stack
 	 * for later.
 	 */
-	__skb_pull(skb, len);
-	skb_reset_transport_header(skb);
+	if (pull) {
+		__skb_pull(skb, len);
+		skb_reset_transport_header(skb);
+	} else {
+		skb_set_transport_header(skb, len);
+	}
 
 	/* process ESP */
-	return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
-
-drop:
-	kfree_skb(skb);
 	return 0;
 }
 
+/* If it's a keepalive packet, then just eat it.
+ * If it's an encapsulated packet, then pass it to the
+ * IPsec xfrm input.
+ * Returns 0 if skb passed to xfrm or was dropped.
+ * Returns >0 if skb should be passed to UDP.
+ * Returns <0 if skb should be resubmitted (-ret is protocol)
+ */
+int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	int ret;
+
+	ret = __xfrm4_udp_encap_rcv(sk, skb, true);
+	if (!ret)
+		return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0,
+				       udp_sk(sk)->encap_type);
+
+	if (ret < 0) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	return ret;
+}
+
+struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
+					struct sk_buff *skb)
+{
+	int offset = skb_gro_offset(skb);
+	const struct net_offload *ops;
+	struct sk_buff *pp = NULL;
+	int ret;
+
+	offset = offset - sizeof(struct udphdr);
+
+	if (!pskb_pull(skb, offset))
+		return NULL;
+
+	if (!refcount_inc_not_zero(&sk->sk_refcnt))
+		return NULL;
+
+	rcu_read_lock();
+	ops = rcu_dereference(inet_offloads[IPPROTO_ESP]);
+	if (!ops || !ops->callbacks.gro_receive)
+		goto out;
+
+	ret = __xfrm4_udp_encap_rcv(sk, skb, false);
+	if (ret)
+		goto out;
+
+	skb->sk = sk;
+	skb_push(skb, offset);
+	NAPI_GRO_CB(skb)->proto = IPPROTO_UDP;
+
+	pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
+	rcu_read_unlock();
+
+	return pp;
+
+out:
+	rcu_read_unlock();
+	sock_put(sk);
+	skb_push(skb, offset);
+	NAPI_GRO_CB(skb)->same_flow = 0;
+	NAPI_GRO_CB(skb)->flush = 1;
+
+	return NULL;
+}
+
 int xfrm4_rcv(struct sk_buff *skb)
 {
 	return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);