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Date: Wed, 16 Aug 2023 14:15:01 +0300
From: Eyal Birger <eyal.birger@...il.com>
To: antony.antony@...unet.com
Cc: Steffen Klassert <steffen.klassert@...unet.com>, Herbert Xu <herbert@...dor.apana.org.au>,
devel@...ux-ipsec.org, netdev@...r.kernel.org
Subject: Re: [PATCH v4 ipsec-next 2/3] xfrm: Support GRO for IPv4 ESP in UDP encapsulation.
Hi Antony,
On Wed, Aug 16, 2023 at 12:57 PM Antony Antony
<antony.antony@...unet.com> wrote:
>
> From: Steffen Klassert <steffen.klassert@...unet.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@...unet.com>
> Co-developed-by: Antony Antony <antony.antony@...unet.com>
> Signed-off-by: Antony Antony <antony.antony@...unet.com>
> ---
> include/net/gro.h | 2 +-
> include/net/xfrm.h | 4 ++
> net/ipv4/esp4_offload.c | 6 ++-
> net/ipv4/udp.c | 16 ++++++-
> net/ipv4/xfrm4_input.c | 98 ++++++++++++++++++++++++++++++++---------
> 5 files changed, 103 insertions(+), 23 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 33ee3f5936e6..e980f442ddcd 100644
> --- a/include/net/xfrm.h
> +++ b/include/net/xfrm.h
> @@ -1671,6 +1671,8 @@ 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);
Why does this function need to be declared twice in this file?
> int xfrm4_transport_finish(struct sk_buff *skb, int async);
> int xfrm4_rcv(struct sk_buff *skb);
>
> @@ -1711,6 +1713,8 @@ 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..34ebfdf0e986 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 +70,9 @@ static struct sk_buff *esp4_gro_receive(struct list_head *head,
>
> xo->flags |= XFRM_GRO;
>
> + if (NAPI_GRO_CB(skb)->proto == IPPROTO_UDP)
> + encap_type = UDP_ENCAP_ESPINUDP;
> +
> 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 +80,7 @@ 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 aa32afd871ee..337607b17ebd 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -2681,6 +2681,17 @@ void udp_destroy_sock(struct sock *sk)
> }
> }
>
> +static void set_xfrm_gro_udp_encap_rcv(__u16 encap_type, unsigned short family,
> + struct udp_sock *up)
> +{
> +#ifdef CONFIG_XFRM
> + if (up->gro_enabled && encap_type == UDP_ENCAP_ESPINUDP) {
> + if (family == AF_INET)
> + up->gro_receive = xfrm4_gro_udp_encap_rcv;
> + }
> +#endif
> +}
> +
> /*
> * Socket option code for UDP
> */
> @@ -2730,12 +2741,14 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
> case 0:
> #ifdef CONFIG_XFRM
> case UDP_ENCAP_ESPINUDP:
> + set_xfrm_gro_udp_encap_rcv(val, sk->sk_family, up);
> + fallthrough;
> case UDP_ENCAP_ESPINUDP_NON_IKE:
> #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)
Why is this change needed?
> up->encap_rcv = xfrm4_udp_encap_rcv;
> #endif
> fallthrough;
> @@ -2773,6 +2786,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
> udp_tunnel_encap_enable(sk->sk_socket);
> up->gro_enabled = valbool;
> up->accept_udp_l4 = valbool;
> + set_xfrm_gro_udp_encap_rcv(up->encap_type, sk->sk_family, up);
> release_sock(sk);
> break;
>
> diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
> index ad2afeef4f10..b57f477c745e 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;
> @@ -90,8 +85,8 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
> __be32 *udpdata32;
> __u16 encap_type = up->encap_type;
>
> - /* if this is not encapsulated socket, then just return now */
> - if (!encap_type)
> + /* if unknown encap_type then just return now */
> + if (encap_type != UDP_ENCAP_ESPINUDP && encap_type != UDP_ENCAP_ESPINUDP_NON_IKE)
This change is unclear to me - the patch adds support for GRO on
UDP_ENCAP_ESPINUDP.
How can we now get other encap types here? and why wasn't the old condition ok?
> return 1;
>
> /* If this is a paged skb, make sure we pull up
> @@ -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 +142,87 @@ 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;
> +
> + 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_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();
> + 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
>
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