/*
* 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/if_ether.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
#include <linux/skbuff.h>
-#include <linux/spinlock.h>
-#include <net/inet_ecn.h>
+#include <linux/netfilter_ipv4.h>
+#include <net/dst.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
-/* Add encapsulation header.
- *
- * In transport mode, the IP header will be moved forward to make space
- * for the encapsulation header.
- *
- * In tunnel mode, the top IP header will be constructed per RFC 2401.
- * The following fields in it shall be filled in by x->type->output:
- * tot_len
- * check
- *
- * On exit, skb->h will be set to the start of the payload to be processed
- * by x->type->output and skb->nh will be set to the top IP header.
- */
-static void xfrm4_encap(struct sk_buff *skb)
-{
- struct dst_entry *dst = skb->dst;
- struct xfrm_state *x = dst->xfrm;
- struct iphdr *iph, *top_iph;
-
- iph = skb->nh.iph;
- skb->h.ipiph = iph;
-
- skb->nh.raw = skb_push(skb, x->props.header_len);
- top_iph = skb->nh.iph;
-
- if (!x->props.mode) {
- skb->h.raw += iph->ihl*4;
- memmove(top_iph, iph, iph->ihl*4);
- return;
- }
-
- top_iph->ihl = 5;
- top_iph->version = 4;
-
- /* DS disclosed */
- top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);
- if (x->props.flags & XFRM_STATE_NOECN)
- IP_ECN_clear(top_iph);
-
- top_iph->frag_off = iph->frag_off & htons(IP_DF);
- if (!top_iph->frag_off)
- __ip_select_ident(top_iph, dst, 0);
-
- top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);
-
- top_iph->saddr = x->props.saddr.a4;
- top_iph->daddr = x->id.daddr.a4;
- top_iph->protocol = IPPROTO_IPIP;
-
- memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
-}
-
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)
+ if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df)
goto out;
dst = skb->dst;
return ret;
}
-int xfrm4_output(struct sk_buff *skb)
+int xfrm4_extract_output(struct xfrm_state *x, 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;
- }
- spin_lock_bh(&x->lock);
- err = xfrm_state_check(x, skb);
+ err = xfrm4_tunnel_check_size(skb);
if (err)
- goto error;
+ return err;
- xfrm4_encap(skb);
+ XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
+
+ return xfrm4_extract_header(skb);
+}
- err = x->type->output(x, skb);
+int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ int err;
+
+ err = xfrm_inner_extract_output(x, skb);
if (err)
- goto error;
+ return err;
+
+ memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+ IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED;
- x->curlft.bytes += skb->len;
- x->curlft.packets++;
+ skb->protocol = htons(ETH_P_IP);
- spin_unlock_bh(&x->lock);
-
- if (!(skb->dst = dst_pop(dst))) {
- err = -EHOSTUNREACH;
- goto error_nolock;
+ return x->outer_mode->output2(x, skb);
+}
+EXPORT_SYMBOL(xfrm4_prepare_output);
+
+static int xfrm4_output_finish(struct sk_buff *skb)
+{
+#ifdef CONFIG_NETFILTER
+ if (!skb->dst->xfrm) {
+ IPCB(skb)->flags |= IPSKB_REROUTED;
+ return dst_output(skb);
}
- err = NET_XMIT_BYPASS;
-
-out_exit:
- return err;
-error:
- spin_unlock_bh(&x->lock);
-error_nolock:
- kfree_skb(skb);
- goto out_exit;
+
+ IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
+#endif
+
+ skb->protocol = htons(ETH_P_IP);
+ return xfrm_output(skb);
+}
+
+int xfrm4_output(struct sk_buff *skb)
+{
+ return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb,
+ NULL, skb->dst->dev, xfrm4_output_finish,
+ !(IPCB(skb)->flags & IPSKB_REROUTED));
}