/* * xfrm6_mode_transport.c - Transport mode encapsulation for IPv6. * * Copyright (C) 2002 USAGI/WIDE Project * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au> */ #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/skbuff.h> #include <linux/stringify.h> #include <net/dst.h> #include <net/ipv6.h> #include <net/xfrm.h> /* Add encapsulation header. * * The IP header and mutable extension headers will be moved forward to make * space for the encapsulation header. * * 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 int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb) { struct ipv6hdr *iph; u8 *prevhdr; int hdr_len; skb_push(skb, x->props.header_len); iph = skb->nh.ipv6h; hdr_len = x->type->hdr_offset(x, skb, &prevhdr); skb->nh.raw = prevhdr - x->props.header_len; skb->h.raw = skb->data + hdr_len; memmove(skb->data, iph, hdr_len); return 0; } /* Remove encapsulation header. * * The IP header will be moved over the top of the encapsulation header. * * On entry, skb->h shall point to where the IP header should be and skb->nh * shall be set to where the IP header currently is. skb->data shall point * to the start of the payload. */ static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb) { int ihl = skb->data - skb->h.raw; if (skb->h.raw != skb->nh.raw) skb->nh.raw = memmove(skb->h.raw, skb->nh.raw, ihl); skb->nh.ipv6h->payload_len = htons(skb->len + ihl - sizeof(struct ipv6hdr)); skb->h.raw = skb->data; return 0; } static struct xfrm_mode xfrm6_transport_mode = { .input = xfrm6_transport_input, .output = xfrm6_transport_output, .owner = THIS_MODULE, .encap = XFRM_MODE_TRANSPORT, }; static int __init xfrm6_transport_init(void) { return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6); } static void __exit xfrm6_transport_exit(void) { int err; err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6); BUG_ON(err); } module_init(xfrm6_transport_init); module_exit(xfrm6_transport_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);