ceb1eec829
This patch moves the setting of the IP length and checksum fields out of the transforms and into the xfrmX_output functions. This would help future efforts in merging the transforms themselves. It also adds an optimisation to ipcomp due to the fact that the transport offset is guaranteed to be zero. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
161 lines
3.7 KiB
C
161 lines
3.7 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 *outer_iph = ip_hdr(skb);
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struct iphdr *inner_iph = ipip_hdr(skb);
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if (INET_ECN_is_ce(outer_iph->tos))
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IP_ECN_set_ce(inner_iph);
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}
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static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
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{
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if (INET_ECN_is_ce(iph->tos))
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IP6_ECN_set_ce(ipv6_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 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 xfrm_dst *xdst = (struct xfrm_dst*)dst;
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struct iphdr *iph, *top_iph;
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int flags;
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iph = ip_hdr(skb);
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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(*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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flags = x->props.flags;
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/* DS disclosed */
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if (xdst->route->ops->family == AF_INET) {
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top_iph->protocol = IPPROTO_IPIP;
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top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);
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top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
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0 : (iph->frag_off & htons(IP_DF));
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}
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#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
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else {
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struct ipv6hdr *ipv6h = (struct ipv6hdr*)iph;
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top_iph->protocol = IPPROTO_IPV6;
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top_iph->tos = INET_ECN_encapsulate(iph->tos, ipv6_get_dsfield(ipv6h));
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top_iph->frag_off = 0;
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}
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#endif
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if (flags & XFRM_STATE_NOECN)
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IP_ECN_clear(top_iph);
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if (!top_iph->frag_off)
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__ip_select_ident(top_iph, dst->child, 0);
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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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skb->protocol = htons(ETH_P_IP);
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memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
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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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struct iphdr *iph = ip_hdr(skb);
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const unsigned char *old_mac;
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int err = -EINVAL;
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switch (iph->protocol){
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case IPPROTO_IPIP:
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break;
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#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
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case IPPROTO_IPV6:
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break;
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#endif
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default:
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goto out;
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}
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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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iph = ip_hdr(skb);
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if (iph->protocol == IPPROTO_IPIP) {
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if (x->props.flags & XFRM_STATE_DECAP_DSCP)
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ipv4_copy_dscp(iph, 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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}
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#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
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else {
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if (!(x->props.flags & XFRM_STATE_NOECN))
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ipip6_ecn_decapsulate(iph, skb);
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skb->protocol = htons(ETH_P_IPV6);
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}
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#endif
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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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.input = xfrm4_tunnel_input,
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.output = xfrm4_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 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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