148 lines
4.1 KiB
C
148 lines
4.1 KiB
C
/*
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* xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
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*
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* Copyright (C) 2002 USAGI/WIDE Project
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* Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/stringify.h>
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#include <net/dsfield.h>
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#include <net/dst.h>
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#include <net/inet_ecn.h>
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#include <net/ipv6.h>
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#include <net/xfrm.h>
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static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
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{
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struct ipv6hdr *outer_iph = ipv6_hdr(skb);
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struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
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if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
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IP6_ECN_set_ce(inner_iph);
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}
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static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb)
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{
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if (INET_ECN_is_ce(ipv6_get_dsfield(ipv6_hdr(skb))))
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IP_ECN_set_ce(ipip_hdr(skb));
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}
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/* Add encapsulation header.
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*
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* The top IP header will be constructed per RFC 2401. The following fields
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* in it shall be filled in by x->type->output:
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* payload_len
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*
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* On exit, skb->h will be set to the start of the encapsulation header to be
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* filled in by x->type->output and skb->nh will be set to the nextheader field
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* of the extension header directly preceding the encapsulation header, or in
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* its absence, that of the top IP header. The value of skb->data will always
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* point to the top IP header.
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*/
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static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct dst_entry *dst = skb->dst;
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struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
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struct ipv6hdr *iph, *top_iph;
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int dsfield;
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skb_push(skb, x->props.header_len);
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iph = ipv6_hdr(skb);
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skb_reset_network_header(skb);
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top_iph = ipv6_hdr(skb);
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skb->transport_header = skb->network_header + sizeof(struct ipv6hdr);
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skb->network_header += offsetof(struct ipv6hdr, nexthdr);
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top_iph->version = 6;
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if (xdst->route->ops->family == AF_INET6) {
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top_iph->priority = iph->priority;
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top_iph->flow_lbl[0] = iph->flow_lbl[0];
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top_iph->flow_lbl[1] = iph->flow_lbl[1];
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top_iph->flow_lbl[2] = iph->flow_lbl[2];
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top_iph->nexthdr = IPPROTO_IPV6;
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} else {
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top_iph->priority = 0;
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top_iph->flow_lbl[0] = 0;
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top_iph->flow_lbl[1] = 0;
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top_iph->flow_lbl[2] = 0;
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top_iph->nexthdr = IPPROTO_IPIP;
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}
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dsfield = ipv6_get_dsfield(top_iph);
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dsfield = INET_ECN_encapsulate(dsfield, dsfield);
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if (x->props.flags & XFRM_STATE_NOECN)
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dsfield &= ~INET_ECN_MASK;
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ipv6_change_dsfield(top_iph, 0, dsfield);
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top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
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ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
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ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
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skb->protocol = htons(ETH_P_IPV6);
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return 0;
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}
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static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err = -EINVAL;
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const unsigned char *old_mac;
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const unsigned char *nh = skb_network_header(skb);
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if (nh[IP6CB(skb)->nhoff] != IPPROTO_IPV6 &&
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nh[IP6CB(skb)->nhoff] != IPPROTO_IPIP)
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goto out;
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if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
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goto out;
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if (skb_cloned(skb) &&
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(err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
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goto out;
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nh = skb_network_header(skb);
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if (nh[IP6CB(skb)->nhoff] == IPPROTO_IPV6) {
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if (x->props.flags & XFRM_STATE_DECAP_DSCP)
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ipv6_copy_dscp(ipv6_hdr(skb), ipipv6_hdr(skb));
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if (!(x->props.flags & XFRM_STATE_NOECN))
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ipip6_ecn_decapsulate(skb);
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} else {
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if (!(x->props.flags & XFRM_STATE_NOECN))
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ip6ip_ecn_decapsulate(skb);
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skb->protocol = htons(ETH_P_IP);
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}
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old_mac = skb_mac_header(skb);
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skb_set_mac_header(skb, -skb->mac_len);
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memmove(skb_mac_header(skb), old_mac, skb->mac_len);
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skb_reset_network_header(skb);
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err = 0;
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out:
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return err;
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}
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static struct xfrm_mode xfrm6_tunnel_mode = {
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.input = xfrm6_tunnel_input,
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.output = xfrm6_tunnel_output,
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.owner = THIS_MODULE,
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.encap = XFRM_MODE_TUNNEL,
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};
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static int __init xfrm6_tunnel_init(void)
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{
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return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
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}
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static void __exit xfrm6_tunnel_exit(void)
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{
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int err;
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err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
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BUG_ON(err);
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}
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module_init(xfrm6_tunnel_init);
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module_exit(xfrm6_tunnel_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);
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