aha/net/ipv4/xfrm4_output.c
Herbert Xu 09b8f7a93e [IPSEC]: Handle GSO packets
This patch segments GSO packets received by the IPsec stack.  This can
happen when a NIC driver injects GSO packets into the stack which are
then forwarded to another host.

The primary application of this is going to be Xen where its backend
driver may inject GSO packets into dom0.

Of course this also can be used by other virtualisation schemes such as
VMWare or UML since the tap device could be modified to inject GSO packets
received through splice.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-23 02:07:38 -07:00

173 lines
3.4 KiB
C

/*
* xfrm4_output.c - Common IPsec encapsulation code for IPv4.
* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/compiler.h>
#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/netfilter_ipv4.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
static int xfrm4_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
struct dst_entry *dst;
struct iphdr *iph = skb->nh.iph;
if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
goto out;
IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
if (!(iph->frag_off & htons(IP_DF)) || skb->local_df)
goto out;
dst = skb->dst;
mtu = dst_mtu(dst);
if (skb->len > mtu) {
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
ret = -EMSGSIZE;
}
out:
return ret;
}
static int xfrm4_output_one(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
struct xfrm_state *x = dst->xfrm;
int err;
if (skb->ip_summed == CHECKSUM_HW) {
err = skb_checksum_help(skb, 0);
if (err)
goto error_nolock;
}
if (x->props.mode) {
err = xfrm4_tunnel_check_size(skb);
if (err)
goto error_nolock;
}
do {
spin_lock_bh(&x->lock);
err = xfrm_state_check(x, skb);
if (err)
goto error;
err = x->mode->output(skb);
if (err)
goto error;
err = x->type->output(x, skb);
if (err)
goto error;
x->curlft.bytes += skb->len;
x->curlft.packets++;
spin_unlock_bh(&x->lock);
if (!(skb->dst = dst_pop(dst))) {
err = -EHOSTUNREACH;
goto error_nolock;
}
dst = skb->dst;
x = dst->xfrm;
} while (x && !x->props.mode);
IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
err = 0;
out_exit:
return err;
error:
spin_unlock_bh(&x->lock);
error_nolock:
kfree_skb(skb);
goto out_exit;
}
static int xfrm4_output_finish2(struct sk_buff *skb)
{
int err;
while (likely((err = xfrm4_output_one(skb)) == 0)) {
nf_reset(skb);
err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL,
skb->dst->dev, dst_output);
if (unlikely(err != 1))
break;
if (!skb->dst->xfrm)
return dst_output(skb);
err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL,
skb->dst->dev, xfrm4_output_finish2);
if (unlikely(err != 1))
break;
}
return err;
}
static int xfrm4_output_finish(struct sk_buff *skb)
{
struct sk_buff *segs;
#ifdef CONFIG_NETFILTER
if (!skb->dst->xfrm) {
IPCB(skb)->flags |= IPSKB_REROUTED;
return dst_output(skb);
}
#endif
if (!skb_shinfo(skb)->gso_size)
return xfrm4_output_finish2(skb);
skb->protocol = htons(ETH_P_IP);
segs = skb_gso_segment(skb, 0);
kfree_skb(skb);
if (unlikely(IS_ERR(segs)))
return PTR_ERR(segs);
do {
struct sk_buff *nskb = segs->next;
int err;
segs->next = NULL;
err = xfrm4_output_finish2(segs);
if (unlikely(err)) {
while ((segs = nskb)) {
nskb = segs->next;
segs->next = NULL;
kfree_skb(segs);
}
return err;
}
segs = nskb;
} while (segs);
return 0;
}
int xfrm4_output(struct sk_buff *skb)
{
return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev,
xfrm4_output_finish,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}