1 /*
2  * Header for use in defining a given L4 protocol for connection tracking.
3  *
4  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
5  *	- generalized L3 protocol dependent part.
6  *
7  * Derived from include/linux/netfiter_ipv4/ip_conntrack_protcol.h
8  */
9 
10 #ifndef _NF_CONNTRACK_L4PROTO_H
11 #define _NF_CONNTRACK_L4PROTO_H
12 #include <linux/netlink.h>
13 #include <net/netlink.h>
14 #include <net/netfilter/nf_conntrack.h>
15 
16 struct seq_file;
17 
18 struct nf_conntrack_l4proto {
19 	/* L3 Protocol number. */
20 	u_int16_t l3proto;
21 
22 	/* L4 Protocol number. */
23 	u_int8_t l4proto;
24 
25 	/* Try to fill in the third arg: dataoff is offset past network protocol
26            hdr.  Return true if possible. */
27 	bool (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int dataoff,
28 			     struct nf_conntrack_tuple *tuple);
29 
30 	/* Invert the per-proto part of the tuple: ie. turn xmit into reply.
31 	 * Some packets can't be inverted: return 0 in that case.
32 	 */
33 	bool (*invert_tuple)(struct nf_conntrack_tuple *inverse,
34 			     const struct nf_conntrack_tuple *orig);
35 
36 	/* Returns verdict for packet, or -1 for invalid. */
37 	int (*packet)(struct nf_conn *ct,
38 		      const struct sk_buff *skb,
39 		      unsigned int dataoff,
40 		      enum ip_conntrack_info ctinfo,
41 		      u_int8_t pf,
42 		      unsigned int hooknum,
43 		      unsigned int *timeouts);
44 
45 	/* Called when a new connection for this protocol found;
46 	 * returns TRUE if it's OK.  If so, packet() called next. */
47 	bool (*new)(struct nf_conn *ct, const struct sk_buff *skb,
48 		    unsigned int dataoff, unsigned int *timeouts);
49 
50 	/* Called when a conntrack entry is destroyed */
51 	void (*destroy)(struct nf_conn *ct);
52 
53 	int (*error)(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
54 		     unsigned int dataoff, enum ip_conntrack_info *ctinfo,
55 		     u_int8_t pf, unsigned int hooknum);
56 
57 	/* Print out the per-protocol part of the tuple. Return like seq_* */
58 	int (*print_tuple)(struct seq_file *s,
59 			   const struct nf_conntrack_tuple *);
60 
61 	/* Print out the private part of the conntrack. */
62 	int (*print_conntrack)(struct seq_file *s, struct nf_conn *);
63 
64 	/* Return the array of timeouts for this protocol. */
65 	unsigned int *(*get_timeouts)(struct net *net);
66 
67 	/* convert protoinfo to nfnetink attributes */
68 	int (*to_nlattr)(struct sk_buff *skb, struct nlattr *nla,
69 			 struct nf_conn *ct);
70 	/* Calculate protoinfo nlattr size */
71 	int (*nlattr_size)(void);
72 
73 	/* convert nfnetlink attributes to protoinfo */
74 	int (*from_nlattr)(struct nlattr *tb[], struct nf_conn *ct);
75 
76 	int (*tuple_to_nlattr)(struct sk_buff *skb,
77 			       const struct nf_conntrack_tuple *t);
78 	/* Calculate tuple nlattr size */
79 	int (*nlattr_tuple_size)(void);
80 	int (*nlattr_to_tuple)(struct nlattr *tb[],
81 			       struct nf_conntrack_tuple *t);
82 	const struct nla_policy *nla_policy;
83 
84 	size_t nla_size;
85 
86 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
87 	struct {
88 		size_t obj_size;
89 		int (*nlattr_to_obj)(struct nlattr *tb[], void *data);
90 		int (*obj_to_nlattr)(struct sk_buff *skb, const void *data);
91 
92 		unsigned int nlattr_max;
93 		const struct nla_policy *nla_policy;
94 	} ctnl_timeout;
95 #endif
96 
97 #ifdef CONFIG_SYSCTL
98 	struct ctl_table_header	**ctl_table_header;
99 	struct ctl_table	*ctl_table;
100 	unsigned int		*ctl_table_users;
101 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
102 	struct ctl_table_header	*ctl_compat_table_header;
103 	struct ctl_table	*ctl_compat_table;
104 #endif
105 #endif
106 	/* Protocol name */
107 	const char *name;
108 
109 	/* Module (if any) which this is connected to. */
110 	struct module *me;
111 };
112 
113 /* Existing built-in generic protocol */
114 extern struct nf_conntrack_l4proto nf_conntrack_l4proto_generic;
115 
116 #define MAX_NF_CT_PROTO 256
117 
118 extern struct nf_conntrack_l4proto *
119 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto);
120 
121 extern struct nf_conntrack_l4proto *
122 nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto);
123 extern void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p);
124 
125 /* Protocol registration. */
126 extern int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *proto);
127 extern void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *proto);
128 
129 /* Generic netlink helpers */
130 extern int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
131 				      const struct nf_conntrack_tuple *tuple);
132 extern int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
133 				      struct nf_conntrack_tuple *t);
134 extern int nf_ct_port_nlattr_tuple_size(void);
135 extern const struct nla_policy nf_ct_port_nla_policy[];
136 
137 #ifdef CONFIG_SYSCTL
138 #ifdef DEBUG_INVALID_PACKETS
139 #define LOG_INVALID(net, proto)				\
140 	((net)->ct.sysctl_log_invalid == (proto) ||	\
141 	 (net)->ct.sysctl_log_invalid == IPPROTO_RAW)
142 #else
143 #define LOG_INVALID(net, proto)				\
144 	(((net)->ct.sysctl_log_invalid == (proto) ||	\
145 	  (net)->ct.sysctl_log_invalid == IPPROTO_RAW)	\
146 	 && net_ratelimit())
147 #endif
148 #else
LOG_INVALID(struct net * net,int proto)149 static inline int LOG_INVALID(struct net *net, int proto) { return 0; }
150 #endif /* CONFIG_SYSCTL */
151 
152 #endif /*_NF_CONNTRACK_PROTOCOL_H*/
153