1 #ifndef _NF_CONNTRACK_SYNPROXY_H
2 #define _NF_CONNTRACK_SYNPROXY_H
3 
4 #include <net/netns/generic.h>
5 
6 struct nf_conn_synproxy {
7 	u32	isn;
8 	u32	its;
9 	u32	tsoff;
10 };
11 
12 static inline struct nf_conn_synproxy *nfct_synproxy(const struct nf_conn *ct)
13 {
14 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
15 	return nf_ct_ext_find(ct, NF_CT_EXT_SYNPROXY);
16 #else
17 	return NULL;
18 #endif
19 }
20 
21 static inline struct nf_conn_synproxy *nfct_synproxy_ext_add(struct nf_conn *ct)
22 {
23 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
24 	return nf_ct_ext_add(ct, NF_CT_EXT_SYNPROXY, GFP_ATOMIC);
25 #else
26 	return NULL;
27 #endif
28 }
29 
30 static inline bool nf_ct_add_synproxy(struct nf_conn *ct,
31 				      const struct nf_conn *tmpl)
32 {
33 	if (tmpl && nfct_synproxy(tmpl)) {
34 		if (!nfct_seqadj_ext_add(ct))
35 			return false;
36 
37 		if (!nfct_synproxy_ext_add(ct))
38 			return false;
39 	}
40 
41 	return true;
42 }
43 
44 struct synproxy_stats {
45 	unsigned int			syn_received;
46 	unsigned int			cookie_invalid;
47 	unsigned int			cookie_valid;
48 	unsigned int			cookie_retrans;
49 	unsigned int			conn_reopened;
50 };
51 
52 struct synproxy_net {
53 	struct nf_conn			*tmpl;
54 	struct synproxy_stats __percpu	*stats;
55 	unsigned int			hook_ref4;
56 	unsigned int			hook_ref6;
57 };
58 
59 extern unsigned int synproxy_net_id;
60 static inline struct synproxy_net *synproxy_pernet(struct net *net)
61 {
62 	return net_generic(net, synproxy_net_id);
63 }
64 
65 struct synproxy_options {
66 	u8				options;
67 	u8				wscale;
68 	u16				mss;
69 	u32				tsval;
70 	u32				tsecr;
71 };
72 
73 struct tcphdr;
74 struct xt_synproxy_info;
75 bool synproxy_parse_options(const struct sk_buff *skb, unsigned int doff,
76 			    const struct tcphdr *th,
77 			    struct synproxy_options *opts);
78 unsigned int synproxy_options_size(const struct synproxy_options *opts);
79 void synproxy_build_options(struct tcphdr *th,
80 			    const struct synproxy_options *opts);
81 
82 void synproxy_init_timestamp_cookie(const struct xt_synproxy_info *info,
83 				    struct synproxy_options *opts);
84 void synproxy_check_timestamp_cookie(struct synproxy_options *opts);
85 
86 unsigned int synproxy_tstamp_adjust(struct sk_buff *skb, unsigned int protoff,
87 				    struct tcphdr *th, struct nf_conn *ct,
88 				    enum ip_conntrack_info ctinfo,
89 				    const struct nf_conn_synproxy *synproxy);
90 
91 #endif /* _NF_CONNTRACK_SYNPROXY_H */
92