144 lines
3.5 KiB
C
144 lines
3.5 KiB
C
/*
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* xfrm6_output.c - Common IPsec encapsulation code for IPv6.
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* Copyright (C) 2002 USAGI/WIDE Project
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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/skbuff.h>
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#include <linux/spinlock.h>
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#include <linux/icmpv6.h>
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#include <net/dsfield.h>
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#include <net/inet_ecn.h>
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#include <net/ipv6.h>
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#include <net/xfrm.h>
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/* Add encapsulation header.
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*
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* In transport mode, the IP header and mutable extension headers will be moved
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* forward to make space for the encapsulation header.
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*
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* In tunnel mode, the top IP header will be constructed per RFC 2401.
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* The following fields in it shall be filled in by x->type->output:
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* payload_len
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*
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* On exit, skb->h will be set to the start of the encapsulation header to be
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* filled in by x->type->output and skb->nh will be set to the nextheader field
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* of the extension header directly preceding the encapsulation header, or in
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* its absence, that of the top IP header. The value of skb->data will always
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* point to the top IP header.
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*/
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static void xfrm6_encap(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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struct ipv6hdr *iph, *top_iph;
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int dsfield;
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skb_push(skb, x->props.header_len);
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iph = skb->nh.ipv6h;
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if (!x->props.mode) {
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u8 *prevhdr;
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int hdr_len;
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hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
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skb->nh.raw = prevhdr - x->props.header_len;
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skb->h.raw = skb->data + hdr_len;
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memmove(skb->data, iph, hdr_len);
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return;
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}
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skb->nh.raw = skb->data;
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top_iph = skb->nh.ipv6h;
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skb->nh.raw = &top_iph->nexthdr;
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skb->h.ipv6h = top_iph + 1;
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top_iph->version = 6;
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top_iph->priority = iph->priority;
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top_iph->flow_lbl[0] = iph->flow_lbl[0];
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top_iph->flow_lbl[1] = iph->flow_lbl[1];
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top_iph->flow_lbl[2] = iph->flow_lbl[2];
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dsfield = ipv6_get_dsfield(top_iph);
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dsfield = INET_ECN_encapsulate(dsfield, dsfield);
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if (x->props.flags & XFRM_STATE_NOECN)
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dsfield &= ~INET_ECN_MASK;
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ipv6_change_dsfield(top_iph, 0, dsfield);
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top_iph->nexthdr = IPPROTO_IPV6;
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top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
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ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
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ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
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}
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static int xfrm6_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 = skb->dst;
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mtu = dst_mtu(dst);
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if (mtu < IPV6_MIN_MTU)
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mtu = IPV6_MIN_MTU;
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if (skb->len > mtu) {
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icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
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ret = -EMSGSIZE;
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}
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return ret;
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}
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int xfrm6_output(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 = xfrm6_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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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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xfrm6_encap(skb);
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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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skb->nh.raw = skb->data;
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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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err = NET_XMIT_BYPASS;
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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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