46d6c5ae95
If netfilter changes the packet mark when mangling, the packet is
rerouted using the route_me_harder set of functions. Prior to this
commit, there's one big difference between route_me_harder and the
ordinary initial routing functions, described in the comment above
__ip_queue_xmit():
/* Note: skb->sk can be different from sk, in case of tunnels */
int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
That function goes on to correctly make use of sk->sk_bound_dev_if,
rather than skb->sk->sk_bound_dev_if. And indeed the comment is true: a
tunnel will receive a packet in ndo_start_xmit with an initial skb->sk.
It will make some transformations to that packet, and then it will send
the encapsulated packet out of a *new* socket. That new socket will
basically always have a different sk_bound_dev_if (otherwise there'd be
a routing loop). So for the purposes of routing the encapsulated packet,
the routing information as it pertains to the socket should come from
that socket's sk, rather than the packet's original skb->sk. For that
reason __ip_queue_xmit() and related functions all do the right thing.
One might argue that all tunnels should just call skb_orphan(skb) before
transmitting the encapsulated packet into the new socket. But tunnels do
*not* do this -- and this is wisely avoided in skb_scrub_packet() too --
because features like TSQ rely on skb->destructor() being called when
that buffer space is truely available again. Calling skb_orphan(skb) too
early would result in buffers filling up unnecessarily and accounting
info being all wrong. Instead, additional routing must take into account
the new sk, just as __ip_queue_xmit() notes.
So, this commit addresses the problem by fishing the correct sk out of
state->sk -- it's already set properly in the call to nf_hook() in
__ip_local_out(), which receives the sk as part of its normal
functionality. So we make sure to plumb state->sk through the various
route_me_harder functions, and then make correct use of it following the
example of __ip_queue_xmit().
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
210 lines
5.8 KiB
C
210 lines
5.8 KiB
C
/* IPv6-specific defines for netfilter.
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* (C)1998 Rusty Russell -- This code is GPL.
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* (C)1999 David Jeffery
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* this header was blatantly ripped from netfilter_ipv4.h
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* it's amazing what adding a bunch of 6s can do =8^)
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*/
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#ifndef __LINUX_IP6_NETFILTER_H
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#define __LINUX_IP6_NETFILTER_H
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#include <uapi/linux/netfilter_ipv6.h>
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#include <net/tcp.h>
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/* Check for an extension */
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static inline int
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nf_ip6_ext_hdr(u8 nexthdr)
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{ return (nexthdr == IPPROTO_HOPOPTS) ||
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(nexthdr == IPPROTO_ROUTING) ||
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(nexthdr == IPPROTO_FRAGMENT) ||
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(nexthdr == IPPROTO_ESP) ||
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(nexthdr == IPPROTO_AH) ||
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(nexthdr == IPPROTO_NONE) ||
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(nexthdr == IPPROTO_DSTOPTS);
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}
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/* Extra routing may needed on local out, as the QUEUE target never returns
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* control to the table.
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*/
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struct ip6_rt_info {
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struct in6_addr daddr;
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struct in6_addr saddr;
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u_int32_t mark;
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};
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struct nf_queue_entry;
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struct nf_bridge_frag_data;
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/*
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* Hook functions for ipv6 to allow xt_* modules to be built-in even
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* if IPv6 is a module.
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*/
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struct nf_ipv6_ops {
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#if IS_MODULE(CONFIG_IPV6)
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int (*chk_addr)(struct net *net, const struct in6_addr *addr,
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const struct net_device *dev, int strict);
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int (*route_me_harder)(struct net *net, struct sock *sk, struct sk_buff *skb);
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int (*dev_get_saddr)(struct net *net, const struct net_device *dev,
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const struct in6_addr *daddr, unsigned int srcprefs,
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struct in6_addr *saddr);
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int (*route)(struct net *net, struct dst_entry **dst, struct flowi *fl,
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bool strict);
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u32 (*cookie_init_sequence)(const struct ipv6hdr *iph,
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const struct tcphdr *th, u16 *mssp);
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int (*cookie_v6_check)(const struct ipv6hdr *iph,
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const struct tcphdr *th, __u32 cookie);
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#endif
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void (*route_input)(struct sk_buff *skb);
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int (*fragment)(struct net *net, struct sock *sk, struct sk_buff *skb,
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int (*output)(struct net *, struct sock *, struct sk_buff *));
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int (*reroute)(struct sk_buff *skb, const struct nf_queue_entry *entry);
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#if IS_MODULE(CONFIG_IPV6)
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int (*br_fragment)(struct net *net, struct sock *sk,
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struct sk_buff *skb,
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struct nf_bridge_frag_data *data,
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int (*output)(struct net *, struct sock *sk,
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const struct nf_bridge_frag_data *data,
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struct sk_buff *));
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#endif
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};
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#ifdef CONFIG_NETFILTER
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#include <net/addrconf.h>
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extern const struct nf_ipv6_ops __rcu *nf_ipv6_ops;
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static inline const struct nf_ipv6_ops *nf_get_ipv6_ops(void)
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{
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return rcu_dereference(nf_ipv6_ops);
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}
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static inline int nf_ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
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const struct net_device *dev, int strict)
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{
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#if IS_MODULE(CONFIG_IPV6)
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const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
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if (!v6_ops)
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return 1;
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return v6_ops->chk_addr(net, addr, dev, strict);
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#elif IS_BUILTIN(CONFIG_IPV6)
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return ipv6_chk_addr(net, addr, dev, strict);
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#else
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return 1;
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#endif
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}
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int __nf_ip6_route(struct net *net, struct dst_entry **dst,
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struct flowi *fl, bool strict);
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static inline int nf_ip6_route(struct net *net, struct dst_entry **dst,
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struct flowi *fl, bool strict)
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{
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#if IS_MODULE(CONFIG_IPV6)
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const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
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if (v6ops)
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return v6ops->route(net, dst, fl, strict);
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return -EHOSTUNREACH;
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#endif
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#if IS_BUILTIN(CONFIG_IPV6)
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return __nf_ip6_route(net, dst, fl, strict);
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#else
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return -EHOSTUNREACH;
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#endif
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}
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#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
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int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
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struct nf_bridge_frag_data *data,
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int (*output)(struct net *, struct sock *sk,
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const struct nf_bridge_frag_data *data,
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struct sk_buff *));
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static inline int nf_br_ip6_fragment(struct net *net, struct sock *sk,
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struct sk_buff *skb,
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struct nf_bridge_frag_data *data,
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int (*output)(struct net *, struct sock *sk,
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const struct nf_bridge_frag_data *data,
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struct sk_buff *))
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{
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#if IS_MODULE(CONFIG_IPV6)
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const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
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if (!v6_ops)
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return 1;
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return v6_ops->br_fragment(net, sk, skb, data, output);
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#elif IS_BUILTIN(CONFIG_IPV6)
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return br_ip6_fragment(net, sk, skb, data, output);
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#else
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return 1;
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#endif
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}
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int ip6_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb);
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static inline int nf_ip6_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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#if IS_MODULE(CONFIG_IPV6)
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const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
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if (!v6_ops)
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return -EHOSTUNREACH;
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return v6_ops->route_me_harder(net, sk, skb);
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#elif IS_BUILTIN(CONFIG_IPV6)
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return ip6_route_me_harder(net, sk, skb);
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#else
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return -EHOSTUNREACH;
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#endif
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}
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static inline u32 nf_ipv6_cookie_init_sequence(const struct ipv6hdr *iph,
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const struct tcphdr *th,
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u16 *mssp)
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{
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#if IS_ENABLED(CONFIG_SYN_COOKIES)
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#if IS_MODULE(CONFIG_IPV6)
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const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
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if (v6_ops)
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return v6_ops->cookie_init_sequence(iph, th, mssp);
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#elif IS_BUILTIN(CONFIG_IPV6)
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return __cookie_v6_init_sequence(iph, th, mssp);
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#endif
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#endif
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return 0;
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}
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static inline int nf_cookie_v6_check(const struct ipv6hdr *iph,
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const struct tcphdr *th, __u32 cookie)
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{
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#if IS_ENABLED(CONFIG_SYN_COOKIES)
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#if IS_MODULE(CONFIG_IPV6)
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const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
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if (v6_ops)
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return v6_ops->cookie_v6_check(iph, th, cookie);
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#elif IS_BUILTIN(CONFIG_IPV6)
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return __cookie_v6_check(iph, th, cookie);
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#endif
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#endif
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return 0;
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}
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__sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
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unsigned int dataoff, u_int8_t protocol);
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int ipv6_netfilter_init(void);
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void ipv6_netfilter_fini(void);
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#else /* CONFIG_NETFILTER */
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static inline int ipv6_netfilter_init(void) { return 0; }
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static inline void ipv6_netfilter_fini(void) { return; }
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static inline const struct nf_ipv6_ops *nf_get_ipv6_ops(void) { return NULL; }
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#endif /* CONFIG_NETFILTER */
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#endif /*__LINUX_IP6_NETFILTER_H*/
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