#ifndef _NF_TPROXY_H_ #define _NF_TPROXY_H_ #include enum nf_tproxy_lookup_t { NF_TPROXY_LOOKUP_LISTENER, NF_TPROXY_LOOKUP_ESTABLISHED, }; static inline bool nf_tproxy_sk_is_transparent(struct sock *sk) { if (inet_sk_transparent(sk)) return true; sock_gen_put(sk); return false; } static inline void nf_tproxy_twsk_deschedule_put(struct inet_timewait_sock *tw) { local_bh_disable(); inet_twsk_deschedule_put(tw); local_bh_enable(); } /* assign a socket to the skb -- consumes sk */ static inline void nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk) { skb_orphan(skb); skb->sk = sk; skb->destructor = sock_edemux; } __be32 nf_tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr); /** * nf_tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections * @skb: The skb being processed. * @laddr: IPv4 address to redirect to or zero. * @lport: TCP port to redirect to or zero. * @sk: The TIME_WAIT TCP socket found by the lookup. * * We have to handle SYN packets arriving to TIME_WAIT sockets * differently: instead of reopening the connection we should rather * redirect the new connection to the proxy if there's a listener * socket present. * * nf_tproxy_handle_time_wait4() consumes the socket reference passed in. * * Returns the listener socket if there's one, the TIME_WAIT socket if * no such listener is found, or NULL if the TCP header is incomplete. */ struct sock * nf_tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb, __be32 laddr, __be16 lport, struct sock *sk); /* * This is used when the user wants to intercept a connection matching * an explicit iptables rule. In this case the sockets are assumed * matching in preference order: * * - match: if there's a fully established connection matching the * _packet_ tuple, it is returned, assuming the redirection * already took place and we process a packet belonging to an * established connection * * - match: if there's a listening socket matching the redirection * (e.g. on-port & on-ip of the connection), it is returned, * regardless if it was bound to 0.0.0.0 or an explicit * address. The reasoning is that if there's an explicit rule, it * does not really matter if the listener is bound to an interface * or to 0. The user already stated that he wants redirection * (since he added the rule). * * Please note that there's an overlap between what a TPROXY target * and a socket match will match. Normally if you have both rules the * "socket" match will be the first one, effectively all packets * belonging to established connections going through that one. */ struct sock * nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, const u8 protocol, const __be32 saddr, const __be32 daddr, const __be16 sport, const __be16 dport, const struct net_device *in, const enum nf_tproxy_lookup_t lookup_type); const struct in6_addr * nf_tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr, const struct in6_addr *daddr); /** * nf_tproxy_handle_time_wait6 - handle IPv6 TCP TIME_WAIT reopen redirections * @skb: The skb being processed. * @tproto: Transport protocol. * @thoff: Transport protocol header offset. * @net: Network namespace. * @laddr: IPv6 address to redirect to. * @lport: TCP port to redirect to or zero. * @sk: The TIME_WAIT TCP socket found by the lookup. * * We have to handle SYN packets arriving to TIME_WAIT sockets * differently: instead of reopening the connection we should rather * redirect the new connection to the proxy if there's a listener * socket present. * * nf_tproxy_handle_time_wait6() consumes the socket reference passed in. * * Returns the listener socket if there's one, the TIME_WAIT socket if * no such listener is found, or NULL if the TCP header is incomplete. */ struct sock * nf_tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff, struct net *net, const struct in6_addr *laddr, const __be16 lport, struct sock *sk); struct sock * nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff, const u8 protocol, const struct in6_addr *saddr, const struct in6_addr *daddr, const __be16 sport, const __be16 dport, const struct net_device *in, const enum nf_tproxy_lookup_t lookup_type); #endif /* _NF_TPROXY_H_ */