/* * xfrm6_mode_tunnel.c - Tunnel 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/dsfield.h> #include <net/dst.h> #include <net/inet_ecn.h> #include <net/ipv6.h> #include <net/xfrm.h> static inline void ipip6_ecn_decapsulate(struct sk_buff *skb) { struct ipv6hdr *outer_iph = ipv6_hdr(skb); struct ipv6hdr *inner_iph = ipipv6_hdr(skb); if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph))) IP6_ECN_set_ce(inner_iph); } /* Add encapsulation header. * * The top IP header will be constructed per RFC 2401. */ static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) { struct dst_entry *dst = skb->dst; struct ipv6hdr *top_iph; int dsfield; skb_set_network_header(skb, -x->props.header_len); skb->mac_header = skb->network_header + offsetof(struct ipv6hdr, nexthdr); skb->transport_header = skb->network_header + sizeof(*top_iph); top_iph = ipv6_hdr(skb); top_iph->version = 6; memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl, sizeof(top_iph->flow_lbl)); top_iph->nexthdr = xfrm_af2proto(skb->dst->ops->family); dsfield = XFRM_MODE_SKB_CB(skb)->tos; 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->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); return 0; } static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) { int err = -EINVAL; const unsigned char *old_mac; if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6) goto out; if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) goto out; if (skb_cloned(skb) && (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) goto out; if (x->props.flags & XFRM_STATE_DECAP_DSCP) ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)), ipipv6_hdr(skb)); if (!(x->props.flags & XFRM_STATE_NOECN)) ipip6_ecn_decapsulate(skb); old_mac = skb_mac_header(skb); skb_set_mac_header(skb, -skb->mac_len); memmove(skb_mac_header(skb), old_mac, skb->mac_len); skb_reset_network_header(skb); err = 0; out: return err; } static struct xfrm_mode xfrm6_tunnel_mode = { .input2 = xfrm6_mode_tunnel_input, .input = xfrm_prepare_input, .output2 = xfrm6_mode_tunnel_output, .output = xfrm6_prepare_output, .owner = THIS_MODULE, .encap = XFRM_MODE_TUNNEL, .flags = XFRM_MODE_FLAG_TUNNEL, }; static int __init xfrm6_mode_tunnel_init(void) { return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6); } static void __exit xfrm6_mode_tunnel_exit(void) { int err; err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6); BUG_ON(err); } module_init(xfrm6_mode_tunnel_init); module_exit(xfrm6_mode_tunnel_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);