diff options
Diffstat (limited to 'net/ipv6/xfrm6_output.c')
| -rw-r--r-- | net/ipv6/xfrm6_output.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c new file mode 100644 index 00000000000..601a148f60f --- /dev/null +++ b/net/ipv6/xfrm6_output.c @@ -0,0 +1,143 @@ +/* + * xfrm6_output.c - Common IPsec encapsulation code for IPv6. + * Copyright (C) 2002 USAGI/WIDE Project + * 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/skbuff.h> +#include <linux/spinlock.h> +#include <linux/icmpv6.h> +#include <net/dsfield.h> +#include <net/inet_ecn.h> +#include <net/ipv6.h> +#include <net/xfrm.h> + +/* Add encapsulation header. + * + * In transport mode, the IP header and mutable extension headers 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: + * payload_len + * + * On exit, skb->h will be set to the start of the encapsulation header to be + * filled in by x->type->output and skb->nh will be set to the nextheader field + * of the extension header directly preceding the encapsulation header, or in + * its absence, that of the top IP header. The value of skb->data will always + * point to the top IP header. + */ +static void xfrm6_encap(struct sk_buff *skb) +{ + struct dst_entry *dst = skb->dst; + struct xfrm_state *x = dst->xfrm; + struct ipv6hdr *iph, *top_iph; + int dsfield; + + skb_push(skb, x->props.header_len); + iph = skb->nh.ipv6h; + + if (!x->props.mode) { + u8 *prevhdr; + int hdr_len; + + hdr_len = ip6_find_1stfragopt(skb, &prevhdr); + skb->nh.raw = prevhdr - x->props.header_len; + skb->h.raw = skb->data + hdr_len; + memmove(skb->data, iph, hdr_len); + return; + } + + skb->nh.raw = skb->data; + top_iph = skb->nh.ipv6h; + skb->nh.raw = &top_iph->nexthdr; + skb->h.ipv6h = top_iph + 1; + + top_iph->version = 6; + top_iph->priority = iph->priority; + top_iph->flow_lbl[0] = iph->flow_lbl[0]; + top_iph->flow_lbl[1] = iph->flow_lbl[1]; + top_iph->flow_lbl[2] = iph->flow_lbl[2]; + dsfield = ipv6_get_dsfield(top_iph); + dsfield = INET_ECN_encapsulate(dsfield, dsfield); + if (x->props.flags & XFRM_STATE_NOECN) + dsfield &= ~INET_ECN_MASK; + ipv6_change_dsfield(top_iph, 0, dsfield); + top_iph->nexthdr = IPPROTO_IPV6; + top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT); + ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr); + ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr); +} + +static int xfrm6_tunnel_check_size(struct sk_buff *skb) +{ + int mtu, ret = 0; + struct dst_entry *dst = skb->dst; + + mtu = dst_mtu(dst); + if (mtu < IPV6_MIN_MTU) + mtu = IPV6_MIN_MTU; + + if (skb->len > mtu) { + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); + ret = -EMSGSIZE; + } + + return ret; +} + +int xfrm6_output(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 = xfrm6_tunnel_check_size(skb); + if (err) + goto error_nolock; + } + + spin_lock_bh(&x->lock); + err = xfrm_state_check(x, skb); + if (err) + goto error; + + xfrm6_encap(skb); + + err = x->type->output(x, skb); + if (err) + goto error; + + x->curlft.bytes += skb->len; + x->curlft.packets++; + + spin_unlock_bh(&x->lock); + + skb->nh.raw = skb->data; + + if (!(skb->dst = dst_pop(dst))) { + err = -EHOSTUNREACH; + goto error_nolock; + } + err = NET_XMIT_BYPASS; + +out_exit: + return err; +error: + spin_unlock_bh(&x->lock); +error_nolock: + kfree_skb(skb); + goto out_exit; +} |