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Date: Wed, 17 Oct 2007 00:05:47 +0900 (JST)
From: YOSHIFUJI Hideaki / 吉藤英明
<yoshfuji@...ux-ipv6.org>
To: herbert@...dor.apana.org.au
Cc: davem@...emloft.net, netdev@...r.kernel.org, kaber@...sh.net,
yoshfuji@...ux-ipv6.org, kozakai@...ux-ipv6.org
Subject: Re: [PATCH 11/12] [IPSEC]: Reinject packet instead of calling
netfilter directly on input
Herbert,
I think with this change, we parse extension headers, twice.
We really do not want to do this.
--yoshfuji
In article <E1IhnTz-0003HT-00@...dolin.me.apana.org.au> (at Tue, 16 Oct 2007 22:33:19 +0800), Herbert Xu <herbert@...dor.apana.org.au> says:
> [IPSEC]: Reinject packet instead of calling netfilter directly on input
>
> Currently we call netfilter directly on input after a series of transport
> mode transforms (and BEET but that's a separate bug). This is inconsistent
> because other parts of the stack such AF_PACKET cannot see the decapsulated
> packet. In fact this is a common complaint about the Linux IPsec stack.
>
> Another problem is that there is a potential for stack overflow if we
> encounter a DNAT rule which turns a foreign packet into a local one that
> contains another transport mode SA.
>
> This patch introduces a major behavioural change by reinjecting the
> packet instead of calling netfilter directly.
>
> This solves both of the aformentioned problems.
>
> It is still inconsistent with how we do things on output since we don't
> pass things through AF_PACKET there either but the same inconsistency
> exists for tunnel mode too so it's not a new problem.
>
> To make things easier I've added a new function called netif_rerx which
> resets netfilter and the dst before reinjecting the packet using netif_rx.
> This can be used by other tunnel code as well.
>
> I haven't added a reinject function for RO mode since it can never be
> called on that path and if it does we want to know about it through an
> OOPS.
>
> Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
> ---
>
> include/linux/netdevice.h | 1 +
> include/net/xfrm.h | 8 ++++++++
> net/core/dev.c | 12 ++++++++++++
> net/ipv4/xfrm4_input.c | 24 ++----------------------
> net/ipv4/xfrm4_mode_beet.c | 7 +++++++
> net/ipv4/xfrm4_mode_transport.c | 11 +++++++++++
> net/ipv4/xfrm4_mode_tunnel.c | 7 +++++++
> net/ipv6/xfrm6_input.c | 23 ++---------------------
> net/ipv6/xfrm6_mode_beet.c | 7 +++++++
> net/ipv6/xfrm6_mode_transport.c | 10 ++++++++++
> net/ipv6/xfrm6_mode_tunnel.c | 7 +++++++
> 11 files changed, 74 insertions(+), 43 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 39dd83b..097f911 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -1039,6 +1039,7 @@ extern void dev_kfree_skb_any(struct sk_buff *skb);
> #define HAVE_NETIF_RX 1
> extern int netif_rx(struct sk_buff *skb);
> extern int netif_rx_ni(struct sk_buff *skb);
> +extern int netif_rerx(struct sk_buff *skb);
> #define HAVE_NETIF_RECEIVE_SKB 1
> extern int netif_receive_skb(struct sk_buff *skb);
> extern int dev_valid_name(const char *name);
> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
> index a9e8247..e5ae5fa 100644
> --- a/include/net/xfrm.h
> +++ b/include/net/xfrm.h
> @@ -311,6 +311,14 @@ struct xfrm_mode {
> */
> int (*output)(struct xfrm_state *x,struct sk_buff *skb);
>
> + /*
> + * Reinject packet into stack.
> + *
> + * On entry, the packet is in the state as on exit from the
> + * input function above.
> + */
> + int (*reinject)(struct xfrm_state *x,struct sk_buff *skb);
> +
> struct xfrm_state_afinfo *afinfo;
> struct module *owner;
> unsigned int encap;
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 38b03da..b753ec8 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -1808,6 +1808,18 @@ int netif_rx_ni(struct sk_buff *skb)
>
> EXPORT_SYMBOL(netif_rx_ni);
>
> +/* Reinject a packet that has previously been processed, e.g., by tunneling. */
> +int netif_rerx(struct sk_buff *skb)
> +{
> + nf_reset(skb);
> +
> + dst_release(skb->dst);
> + skb->dst = NULL;
> +
> + return netif_rx(skb);
> +}
> +EXPORT_SYMBOL(netif_rerx);
> +
> static inline struct net_device *skb_bond(struct sk_buff *skb)
> {
> struct net_device *dev = skb->dev;
> diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
> index 5cb0b59..f5576d5 100644
> --- a/net/ipv4/xfrm4_input.c
> +++ b/net/ipv4/xfrm4_input.c
> @@ -41,7 +41,6 @@ int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
> struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
> struct xfrm_state *x;
> int xfrm_nr = 0;
> - int decaps = 0;
> unsigned int nhoff = offsetof(struct iphdr, protocol);
>
> seq = 0;
> @@ -95,7 +94,6 @@ int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
> goto drop;
>
> if (x->props.mode == XFRM_MODE_TUNNEL) {
> - decaps = 1;
> break;
> }
>
> @@ -122,26 +120,8 @@ int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
> xfrm_nr * sizeof(xfrm_vec[0]));
> skb->sp->len += xfrm_nr;
>
> - nf_reset(skb);
> -
> - if (decaps) {
> - dst_release(skb->dst);
> - skb->dst = NULL;
> - netif_rx(skb);
> - return 0;
> - } else {
> -#ifdef CONFIG_NETFILTER
> - __skb_push(skb, skb->data - skb_network_header(skb));
> - ip_hdr(skb)->tot_len = htons(skb->len);
> - ip_send_check(ip_hdr(skb));
> -
> - NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
> - xfrm4_rcv_encap_finish);
> - return 0;
> -#else
> - return -ip_hdr(skb)->protocol;
> -#endif
> - }
> + x->mode->reinject(x, skb);
> + return 0;
>
> drop_unlock:
> spin_unlock(&x->lock);
> diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
> index 73d2338..012ae98 100644
> --- a/net/ipv4/xfrm4_mode_beet.c
> +++ b/net/ipv4/xfrm4_mode_beet.c
> @@ -11,6 +11,7 @@
> #include <linux/init.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/netdevice.h>
> #include <linux/skbuff.h>
> #include <linux/stringify.h>
> #include <net/dst.h>
> @@ -109,9 +110,15 @@ out:
> return err;
> }
>
> +static int xfrm4_beet_reinject(struct xfrm_state *x, struct sk_buff *skb)
> +{
> + return netif_rerx(skb);
> +}
> +
> static struct xfrm_mode xfrm4_beet_mode = {
> .input = xfrm4_beet_input,
> .output = xfrm4_beet_output,
> + .reinject = xfrm4_beet_reinject,
> .owner = THIS_MODULE,
> .encap = XFRM_MODE_BEET,
> };
> diff --git a/net/ipv4/xfrm4_mode_transport.c b/net/ipv4/xfrm4_mode_transport.c
> index fd840c7..602418b 100644
> --- a/net/ipv4/xfrm4_mode_transport.c
> +++ b/net/ipv4/xfrm4_mode_transport.c
> @@ -7,6 +7,7 @@
> #include <linux/init.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/netdevice.h>
> #include <linux/skbuff.h>
> #include <linux/stringify.h>
> #include <net/dst.h>
> @@ -54,9 +55,19 @@ static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
> return 0;
> }
>
> +static int xfrm4_transport_reinject(struct xfrm_state *x, struct sk_buff *skb)
> +{
> + __skb_push(skb, skb->data - skb_network_header(skb));
> + ip_hdr(skb)->tot_len = htons(skb->len);
> + ip_send_check(ip_hdr(skb));
> +
> + return netif_rerx(skb);
> +}
> +
> static struct xfrm_mode xfrm4_transport_mode = {
> .input = xfrm4_transport_input,
> .output = xfrm4_transport_output,
> + .reinject = xfrm4_transport_reinject,
> .owner = THIS_MODULE,
> .encap = XFRM_MODE_TRANSPORT,
> };
> diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
> index 1ae9d32..780908a 100644
> --- a/net/ipv4/xfrm4_mode_tunnel.c
> +++ b/net/ipv4/xfrm4_mode_tunnel.c
> @@ -7,6 +7,7 @@
> #include <linux/init.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/netdevice.h>
> #include <linux/skbuff.h>
> #include <linux/stringify.h>
> #include <net/dst.h>
> @@ -134,9 +135,15 @@ out:
> return err;
> }
>
> +static int xfrm4_tunnel_reinject(struct xfrm_state *x, struct sk_buff *skb)
> +{
> + return netif_rerx(skb);
> +}
> +
> static struct xfrm_mode xfrm4_tunnel_mode = {
> .input = xfrm4_tunnel_input,
> .output = xfrm4_tunnel_output,
> + .reinject = xfrm4_tunnel_reinject,
> .owner = THIS_MODULE,
> .encap = XFRM_MODE_TUNNEL,
> };
> diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c
> index b1201c3..1347e0a 100644
> --- a/net/ipv6/xfrm6_input.c
> +++ b/net/ipv6/xfrm6_input.c
> @@ -23,7 +23,6 @@ int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
> struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
> struct xfrm_state *x;
> int xfrm_nr = 0;
> - int decaps = 0;
> unsigned int nhoff;
>
> nhoff = IP6CB(skb)->nhoff;
> @@ -72,7 +71,6 @@ int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
> goto drop;
>
> if (x->props.mode == XFRM_MODE_TUNNEL) { /* XXX */
> - decaps = 1;
> break;
> }
>
> @@ -98,25 +96,8 @@ int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
> xfrm_nr * sizeof(xfrm_vec[0]));
> skb->sp->len += xfrm_nr;
>
> - nf_reset(skb);
> -
> - if (decaps) {
> - dst_release(skb->dst);
> - skb->dst = NULL;
> - netif_rx(skb);
> - return -1;
> - } else {
> -#ifdef CONFIG_NETFILTER
> - ipv6_hdr(skb)->payload_len = htons(skb->len);
> - __skb_push(skb, skb->data - skb_network_header(skb));
> -
> - NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
> - ip6_rcv_finish);
> - return -1;
> -#else
> - return 1;
> -#endif
> - }
> + x->mode->reinject(x, skb);
> + return -1;
>
> drop_unlock:
> spin_unlock(&x->lock);
> diff --git a/net/ipv6/xfrm6_mode_beet.c b/net/ipv6/xfrm6_mode_beet.c
> index 13bb1e8..17622cf 100644
> --- a/net/ipv6/xfrm6_mode_beet.c
> +++ b/net/ipv6/xfrm6_mode_beet.c
> @@ -11,6 +11,7 @@
> #include <linux/init.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/netdevice.h>
> #include <linux/skbuff.h>
> #include <linux/stringify.h>
> #include <net/dsfield.h>
> @@ -74,9 +75,15 @@ out:
> return err;
> }
>
> +static int xfrm6_beet_reinject(struct xfrm_state *x, struct sk_buff *skb)
> +{
> + return netif_rerx(skb);
> +}
> +
> static struct xfrm_mode xfrm6_beet_mode = {
> .input = xfrm6_beet_input,
> .output = xfrm6_beet_output,
> + .reinject = xfrm6_beet_reinject,
> .owner = THIS_MODULE,
> .encap = XFRM_MODE_BEET,
> };
> diff --git a/net/ipv6/xfrm6_mode_transport.c b/net/ipv6/xfrm6_mode_transport.c
> index 4e34410..e165442 100644
> --- a/net/ipv6/xfrm6_mode_transport.c
> +++ b/net/ipv6/xfrm6_mode_transport.c
> @@ -8,6 +8,7 @@
> #include <linux/init.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/netdevice.h>
> #include <linux/skbuff.h>
> #include <linux/stringify.h>
> #include <net/dst.h>
> @@ -59,9 +60,18 @@ static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
> return 0;
> }
>
> +static int xfrm6_transport_reinject(struct xfrm_state *x, struct sk_buff *skb)
> +{
> + ipv6_hdr(skb)->payload_len = htons(skb->len);
> + __skb_push(skb, skb->data - skb_network_header(skb));
> +
> + return netif_rerx(skb);
> +}
> +
> static struct xfrm_mode xfrm6_transport_mode = {
> .input = xfrm6_transport_input,
> .output = xfrm6_transport_output,
> + .reinject = xfrm6_transport_reinject,
> .owner = THIS_MODULE,
> .encap = XFRM_MODE_TRANSPORT,
> };
> diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
> index ea22838..1329d6a 100644
> --- a/net/ipv6/xfrm6_mode_tunnel.c
> +++ b/net/ipv6/xfrm6_mode_tunnel.c
> @@ -8,6 +8,7 @@
> #include <linux/init.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/netdevice.h>
> #include <linux/skbuff.h>
> #include <linux/stringify.h>
> #include <net/dsfield.h>
> @@ -113,9 +114,15 @@ out:
> return err;
> }
>
> +static int xfrm6_tunnel_reinject(struct xfrm_state *x, struct sk_buff *skb)
> +{
> + return netif_rerx(skb);
> +}
> +
> static struct xfrm_mode xfrm6_tunnel_mode = {
> .input = xfrm6_tunnel_input,
> .output = xfrm6_tunnel_output,
> + .reinject = xfrm6_tunnel_reinject,
> .owner = THIS_MODULE,
> .encap = XFRM_MODE_TUNNEL,
> };
> -
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