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