a947b0a93e
By default, DSCP is copying during encapsulation. Copying the DSCP in IPsec tunneling may be a bit dangerous because packets with different DSCP may get reordered relative to each other in the network and then dropped by the remote IPsec GW if the reordering becomes too big compared to the replay window. It is possible to avoid this copy with netfilter rules, but it's very convenient to be able to configure it for each SA directly. This patch adds a toogle for this purpose. By default, it's not set to maintain backward compatibility. Field flags in struct xfrm_usersa_info is full, hence I add a new attribute. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
121 lines
3 KiB
C
121 lines
3 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/gfp.h>
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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/ip6_route.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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const 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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/* 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_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct dst_entry *dst = skb_dst(skb);
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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 = xfrm_af2proto(skb_dst(skb)->ops->family);
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if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
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dsfield = 0;
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else
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dsfield = XFRM_MODE_SKB_CB(skb)->tos;
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dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
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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 = ip6_dst_hoplimit(dst->child);
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top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
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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_mode_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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if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
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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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err = skb_unclone(skb, GFP_ATOMIC);
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if (err)
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goto out;
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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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skb_reset_network_header(skb);
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skb_mac_header_rebuild(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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.input2 = xfrm6_mode_tunnel_input,
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.input = xfrm_prepare_input,
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.output2 = xfrm6_mode_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_mode_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_mode_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_mode_tunnel_init);
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module_exit(xfrm6_mode_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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