1/* 2 * xfrm6_mode_tunnel.c - Tunnel 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/gfp.h> 9#include <linux/init.h> 10#include <linux/kernel.h> 11#include <linux/module.h> 12#include <linux/skbuff.h> 13#include <linux/stringify.h> 14#include <net/dsfield.h> 15#include <net/dst.h> 16#include <net/inet_ecn.h> 17#include <net/ipv6.h> 18#include <net/xfrm.h> 19 20static inline void ipip6_ecn_decapsulate(struct sk_buff *skb) 21{ 22 struct ipv6hdr *outer_iph = ipv6_hdr(skb); 23 struct ipv6hdr *inner_iph = ipipv6_hdr(skb); 24 25 if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph))) 26 IP6_ECN_set_ce(inner_iph); 27} 28 29/* Add encapsulation header. 30 * 31 * The top IP header will be constructed per RFC 2401. 32 */ 33static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) 34{ 35 struct dst_entry *dst = skb_dst(skb); 36 struct ipv6hdr *top_iph; 37 int dsfield; 38 39 skb_set_network_header(skb, -x->props.header_len); 40 skb->mac_header = skb->network_header + 41 offsetof(struct ipv6hdr, nexthdr); 42 skb->transport_header = skb->network_header + sizeof(*top_iph); 43 top_iph = ipv6_hdr(skb); 44 45 top_iph->version = 6; 46 47 memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl, 48 sizeof(top_iph->flow_lbl)); 49 top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family); 50 51 dsfield = XFRM_MODE_SKB_CB(skb)->tos; 52 dsfield = INET_ECN_encapsulate(dsfield, dsfield); 53 if (x->props.flags & XFRM_STATE_NOECN) 54 dsfield &= ~INET_ECN_MASK; 55 ipv6_change_dsfield(top_iph, 0, dsfield); 56 top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT); 57 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr); 58 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr); 59 return 0; 60} 61 62static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) 63{ 64 int err = -EINVAL; 65 const unsigned char *old_mac; 66 67 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6) 68 goto out; 69 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 70 goto out; 71 72 if (skb_cloned(skb) && 73 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) 74 goto out; 75 76 if (x->props.flags & XFRM_STATE_DECAP_DSCP) 77 ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)), 78 ipipv6_hdr(skb)); 79 if (!(x->props.flags & XFRM_STATE_NOECN)) 80 ipip6_ecn_decapsulate(skb); 81 82 old_mac = skb_mac_header(skb); 83 skb_set_mac_header(skb, -skb->mac_len); 84 memmove(skb_mac_header(skb), old_mac, skb->mac_len); 85 skb_reset_network_header(skb); 86 err = 0; 87 88out: 89 return err; 90} 91 92static struct xfrm_mode xfrm6_tunnel_mode = { 93 .input2 = xfrm6_mode_tunnel_input, 94 .input = xfrm_prepare_input, 95 .output2 = xfrm6_mode_tunnel_output, 96 .output = xfrm6_prepare_output, 97 .owner = THIS_MODULE, 98 .encap = XFRM_MODE_TUNNEL, 99 .flags = XFRM_MODE_FLAG_TUNNEL, 100}; 101 102static int __init xfrm6_mode_tunnel_init(void) 103{ 104 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6); 105} 106 107static void __exit xfrm6_mode_tunnel_exit(void) 108{ 109 int err; 110 111 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6); 112 BUG_ON(err); 113} 114 115module_init(xfrm6_mode_tunnel_init); 116module_exit(xfrm6_mode_tunnel_exit); 117MODULE_LICENSE("GPL"); 118MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL); 119