227620e295
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 input path so that each function deals with one family only. In particular, the functions xfrm4_extract_inut/xfrm6_extract_inut moves the pertinent fields from the IPv4/IPv6 IP headers into a neutral format stored in skb->cb. This is then used by the inner mode input functions to modify the inner IP header. In this way the input function no longer has to know about the outer address family. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
122 lines
2.9 KiB
C
122 lines
2.9 KiB
C
/*
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* xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
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*
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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/dst.h>
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#include <net/inet_ecn.h>
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#include <net/ip.h>
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#include <net/xfrm.h>
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static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
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{
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struct iphdr *inner_iph = ipip_hdr(skb);
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if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
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IP_ECN_set_ce(inner_iph);
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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 xfrm4_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 iphdr *top_iph;
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int flags;
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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 iphdr, protocol);
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skb->transport_header = skb->network_header + sizeof(*top_iph);
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top_iph = ip_hdr(skb);
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top_iph->ihl = 5;
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top_iph->version = 4;
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top_iph->protocol = x->inner_mode->afinfo->proto;
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/* DS disclosed */
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top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos,
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XFRM_MODE_SKB_CB(skb)->tos);
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flags = x->props.flags;
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if (flags & XFRM_STATE_NOECN)
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IP_ECN_clear(top_iph);
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top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
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0 : XFRM_MODE_SKB_CB(skb)->frag_off;
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ip_select_ident(top_iph, dst->child, NULL);
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top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);
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top_iph->saddr = x->props.saddr.a4;
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top_iph->daddr = x->id.daddr.a4;
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return 0;
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}
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static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
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{
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const unsigned char *old_mac;
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int err = -EINVAL;
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if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
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goto out;
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if (!pskb_may_pull(skb, sizeof(struct iphdr)))
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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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if (x->props.flags & XFRM_STATE_DECAP_DSCP)
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ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
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if (!(x->props.flags & XFRM_STATE_NOECN))
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ipip_ecn_decapsulate(skb);
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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 xfrm4_tunnel_mode = {
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.input2 = xfrm4_tunnel_input,
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.input = xfrm_prepare_input,
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.output2 = xfrm4_tunnel_output,
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.output = xfrm4_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 xfrm4_tunnel_init(void)
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{
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return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
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}
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static void __exit xfrm4_tunnel_exit(void)
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{
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int err;
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err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
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BUG_ON(err);
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}
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module_init(xfrm4_tunnel_init);
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module_exit(xfrm4_tunnel_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);
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