| /* |
| * xfrm4_mode_transport.c - Transport mode encapsulation for IPv4. |
| * |
| * 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/ip.h> |
| #include <net/xfrm.h> |
| |
| /* Add encapsulation header. |
| * |
| * The IP header will be moved forward to make space for the encapsulation |
| * header. |
| */ |
| static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb) |
| { |
| struct iphdr *iph = ip_hdr(skb); |
| int ihl = iph->ihl * 4; |
| |
| skb_set_network_header(skb, -x->props.header_len); |
| skb->mac_header = skb->network_header + |
| offsetof(struct iphdr, protocol); |
| skb->transport_header = skb->network_header + ihl; |
| __skb_pull(skb, ihl); |
| memmove(skb_network_header(skb), iph, ihl); |
| 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 xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb) |
| { |
| int ihl = skb->data - skb_transport_header(skb); |
| struct xfrm_offload *xo = xfrm_offload(skb); |
| |
| if (skb->transport_header != skb->network_header) { |
| memmove(skb_transport_header(skb), |
| skb_network_header(skb), ihl); |
| skb->network_header = skb->transport_header; |
| } |
| ip_hdr(skb)->tot_len = htons(skb->len + ihl); |
| if (!xo || !(xo->flags & XFRM_GRO)) |
| skb_reset_transport_header(skb); |
| return 0; |
| } |
| |
| static struct xfrm_mode xfrm4_transport_mode = { |
| .input = xfrm4_transport_input, |
| .output = xfrm4_transport_output, |
| .owner = THIS_MODULE, |
| .encap = XFRM_MODE_TRANSPORT, |
| }; |
| |
| static int __init xfrm4_transport_init(void) |
| { |
| return xfrm_register_mode(&xfrm4_transport_mode, AF_INET); |
| } |
| |
| static void __exit xfrm4_transport_exit(void) |
| { |
| int err; |
| |
| err = xfrm_unregister_mode(&xfrm4_transport_mode, AF_INET); |
| BUG_ON(err); |
| } |
| |
| module_init(xfrm4_transport_init); |
| module_exit(xfrm4_transport_exit); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TRANSPORT); |