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36cf9acf93
With inter-family transforms the inner mode differs from the outer mode. Attempting to handle both sides from the same function means that it needs to handle both IPv4 and IPv6 which creates duplication and confusion. This patch separates the two parts on the output path so that each function deals with one family only. In particular, the functions xfrm4_extract_output/xfrm6_extract_output moves the pertinent fields from the IPv4/IPv6 IP headers into a neutral format stored in skb->cb. This is then used by the outer mode output functions to write the outer IP header. In this way the output function no longer has to know about the inner address family. Since the extract functions are only called by tunnel modes (the only modes that can support inter-family transforms), I've also moved the xfrm*_tunnel_check_size calls into them. This allows the correct ICMP message to be sent as opposed to now where you might call icmp_send with an IPv6 packet and vice versa. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
131 lines
3.4 KiB
C
131 lines
3.4 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.
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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 ipv6hdr *top_iph;
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int dsfield;
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skb_set_network_header(skb, -x->props.header_len);
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skb->mac_header = skb->network_header +
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offsetof(struct ipv6hdr, nexthdr);
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skb->transport_header = skb->network_header + sizeof(*top_iph);
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top_iph = ipv6_hdr(skb);
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top_iph->version = 6;
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memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
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sizeof(top_iph->flow_lbl));
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top_iph->nexthdr = x->inner_mode->afinfo->proto;
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dsfield = XFRM_MODE_SKB_CB(skb)->tos;
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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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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_get_dsfield(ipv6_hdr(skb)),
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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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.output2 = xfrm6_tunnel_output,
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.output = xfrm6_prepare_output,
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.owner = THIS_MODULE,
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.encap = XFRM_MODE_TUNNEL,
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.flags = XFRM_MODE_FLAG_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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