LXR linux/net/ipv6/xfrm6_mode

   1/*
   2 * xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
   3 *
   4 * Copyright (C) 2002 USAGI/WIDE Project
   5 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
   6 */
   7
   8#include <linux/init.h>
   9#include <linux/kernel.h>
  10#include <linux/module.h>
  11#include <linux/skbuff.h>
  12#include <linux/stringify.h>
  13#include <net/dst.h>
  14#include <net/ipv6.h>
  15#include <net/xfrm.h>
  16#include <net/protocol.h>
  17
  18/* Add encapsulation header.
  19 *
  20 * The IP header and mutable extension headers will be moved forward to make
  21 * space for the encapsulation header.
  22 */
  23static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
  24{
  25        struct ipv6hdr *iph;
  26        u8 *prevhdr;
  27        int hdr_len;
  28
  29        iph = ipv6_hdr(skb);
  30        skb_set_inner_transport_header(skb, skb_transport_offset(skb));
  31
  32        hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
  33        if (hdr_len < 0)
  34                return hdr_len;
  35        skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
  36        skb_set_network_header(skb, -x->props.header_len);
  37        skb->transport_header = skb->network_header + hdr_len;
  38        __skb_pull(skb, hdr_len);
  39        memmove(ipv6_hdr(skb), iph, hdr_len);
  40        return 0;
  41}
  42
  43/* Remove encapsulation header.
  44 *
  45 * The IP header will be moved over the top of the encapsulation header.
  46 *
  47 * On entry, skb->h shall point to where the IP header should be and skb->nh
  48 * shall be set to where the IP header currently is.  skb->data shall point
  49 * to the start of the payload.
  50 */
  51static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
  52{
  53        int ihl = skb->data - skb_transport_header(skb);
  54        struct xfrm_offload *xo = xfrm_offload(skb);
  55
  56        if (skb->transport_header != skb->network_header) {
  57                memmove(skb_transport_header(skb),
  58                        skb_network_header(skb), ihl);
  59                skb->network_header = skb->transport_header;
  60        }
  61        ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
  62                                           sizeof(struct ipv6hdr));
  63        if (!xo || !(xo->flags & XFRM_GRO))
  64                skb_reset_transport_header(skb);
  65        return 0;
  66}
  67
  68static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
  69                                                   struct sk_buff *skb,
  70                                                   netdev_features_t features)
  71{
  72        const struct net_offload *ops;
  73        struct sk_buff *segs = ERR_PTR(-EINVAL);
  74        struct xfrm_offload *xo = xfrm_offload(skb);
  75
  76        skb->transport_header += x->props.header_len;
  77        ops = rcu_dereference(inet6_offloads[xo->proto]);
  78        if (likely(ops && ops->callbacks.gso_segment))
  79                segs = ops->callbacks.gso_segment(skb, features);
  80
  81        return segs;
  82}
  83
  84static void xfrm6_transport_xmit(struct xfrm_state *x, struct sk_buff *skb)
  85{
  86        struct xfrm_offload *xo = xfrm_offload(skb);
  87
  88        skb_reset_mac_len(skb);
  89        pskb_pull(skb, skb->mac_len + sizeof(struct ipv6hdr) + x->props.header_len);
  90
  91        if (xo->flags & XFRM_GSO_SEGMENT) {
  92                 skb_reset_transport_header(skb);
  93                 skb->transport_header -= x->props.header_len;
  94        }
  95}
  96
  97
  98static struct xfrm_mode xfrm6_transport_mode = {
  99        .input = xfrm6_transport_input,
 100        .output = xfrm6_transport_output,
 101        .gso_segment = xfrm4_transport_gso_segment,
 102        .xmit = xfrm6_transport_xmit,
 103        .owner = THIS_MODULE,
 104        .encap = XFRM_MODE_TRANSPORT,
 105};
 106
 107static int __init xfrm6_transport_init(void)
 108{
 109        return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
 110}
 111
 112static void __exit xfrm6_transport_exit(void)
 113{
 114        int err;
 115
 116        err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
 117        BUG_ON(err);
 118}
 119
 120module_init(xfrm6_transport_init);
 121module_exit(xfrm6_transport_exit);
 122MODULE_LICENSE("GPL");
 123MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);
 124