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/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/dsfield.h> 14#include <net/dst.h> 15#include <net/inet_ecn.h> 16#include <net/ipv6.h> 17#include <net/xfrm.h> 18 19static inline void ipip6_ecn_decapsulate(struct sk_buff *skb) 20{ 21 struct ipv6hdr *outer_iph = ipv6_hdr(skb); 22 struct ipv6hdr *inner_iph = ipipv6_hdr(skb); 23 24 if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph))) 25 IP6_ECN_set_ce(inner_iph); 26} 27 28static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb) 29{ 30 if (INET_ECN_is_ce(ipv6_get_dsfield(ipv6_hdr(skb)))) 31 IP_ECN_set_ce(ipip_hdr(skb)); 32} 33 34/* Add encapsulation header. 35 * 36 * The top IP header will be constructed per RFC 2401. The following fields 37 * in it shall be filled in by x->type->output: 38 * payload_len 39 * 40 * On exit, skb->h will be set to the start of the encapsulation header to be 41 * filled in by x->type->output and skb->nh will be set to the nextheader field 42 * of the extension header directly preceding the encapsulation header, or in 43 * its absence, that of the top IP header. The value of skb->data will always 44 * point to the top IP header. 45 */ 46static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) 47{ 48 struct dst_entry *dst = skb->dst; 49 struct xfrm_dst *xdst = (struct xfrm_dst*)dst; 50 struct ipv6hdr *iph, *top_iph; 51 int dsfield; 52 53 skb_push(skb, x->props.header_len); 54 iph = ipv6_hdr(skb); 55 56 skb_reset_network_header(skb); 57 top_iph = ipv6_hdr(skb); 58 skb->transport_header = skb->network_header + sizeof(struct ipv6hdr); 59 skb->network_header += offsetof(struct ipv6hdr, nexthdr); 60 61 top_iph->version = 6; 62 if (xdst->route->ops->family == AF_INET6) { 63 top_iph->priority = iph->priority; 64 top_iph->flow_lbl[0] = iph->flow_lbl[0]; 65 top_iph->flow_lbl[1] = iph->flow_lbl[1]; 66 top_iph->flow_lbl[2] = iph->flow_lbl[2]; 67 top_iph->nexthdr = IPPROTO_IPV6; 68 } else { 69 top_iph->priority = 0; 70 top_iph->flow_lbl[0] = 0; 71 top_iph->flow_lbl[1] = 0; 72 top_iph->flow_lbl[2] = 0; 73 top_iph->nexthdr = IPPROTO_IPIP; 74 } 75 dsfield = ipv6_get_dsfield(top_iph); 76 dsfield = INET_ECN_encapsulate(dsfield, dsfield); 77 if (x->props.flags & XFRM_STATE_NOECN) 78 dsfield &= ~INET_ECN_MASK; 79 ipv6_change_dsfield(top_iph, 0, dsfield); 80 top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT); 81 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr); 82 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr); 83 skb->protocol = htons(ETH_P_IPV6); 84 return 0; 85} 86 87static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) 88{ 89 int err = -EINVAL; 90 const unsigned char *old_mac; 91 const unsigned char *nh = skb_network_header(skb); 92 93 if (nh[IP6CB(skb)->nhoff] != IPPROTO_IPV6 && 94 nh[IP6CB(skb)->nhoff] != IPPROTO_IPIP) 95 goto out; 96 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 97 goto out; 98 99 if (skb_cloned(skb) && 100 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) 101 goto out; 102 103 nh = skb_network_header(skb); 104 if (nh[IP6CB(skb)->nhoff] == IPPROTO_IPV6) { 105 if (x->props.flags & XFRM_STATE_DECAP_DSCP) 106 ipv6_copy_dscp(ipv6_hdr(skb), ipipv6_hdr(skb)); 107 if (!(x->props.flags & XFRM_STATE_NOECN)) 108 ipip6_ecn_decapsulate(skb); 109 } else { 110 if (!(x->props.flags & XFRM_STATE_NOECN)) 111 ip6ip_ecn_decapsulate(skb); 112 skb->protocol = htons(ETH_P_IP); 113 } 114 old_mac = skb_mac_header(skb); 115 skb_set_mac_header(skb, -skb->mac_len); 116 memmove(skb_mac_header(skb), old_mac, skb->mac_len); 117 skb_reset_network_header(skb); 118 err = 0; 119 120out: 121 return err; 122} 123 124static struct xfrm_mode xfrm6_tunnel_mode = { 125 .input = xfrm6_tunnel_input, 126 .output = xfrm6_tunnel_output, 127 .owner = THIS_MODULE, 128 .encap = XFRM_MODE_TUNNEL, 129}; 130 131static int __init xfrm6_tunnel_init(void) 132{ 133 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6); 134} 135 136static void __exit xfrm6_tunnel_exit(void) 137{ 138 int err; 139 140 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6); 141 BUG_ON(err); 142} 143 144module_init(xfrm6_tunnel_init); 145module_exit(xfrm6_tunnel_exit); 146MODULE_LICENSE("GPL"); 147MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL); 148