eae8dee992
Using ipv6_get_dsfield on the outer IP header implies that inner and outer header are of the the same address family. For interfamily tunnels, particularly 646, the code reading the DSCP field obtains the wrong values (IHL and the upper four bits of the DSCP field). This can cause the code to detect a congestion encoutered state in the outer header and enable the corresponding bits in the inner header, too. Since the DSCP field is stored in the xfrm mode common buffer independently from the IP version of the outer header, it's safe (and correct) to take this value from there. Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
126 lines
3.1 KiB
C
126 lines
3.1 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/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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struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
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if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
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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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#define for_each_input_rcu(head, handler) \
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for (handler = rcu_dereference(head); \
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handler != NULL; \
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handler = rcu_dereference(handler->next))
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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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