include/net/netfilter/nf_conntrack_l4proto.h

   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 /* Protocol registration. */
 122 extern int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *proto);
 123 extern void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *proto);
 124
 125 /* Generic netlink helpers */
 126 extern int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
 127                                       const struct nf_conntrack_tuple *tuple);
 128 extern int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
 129                                       struct nf_conntrack_tuple *t);
 130 extern int nf_ct_port_nlattr_tuple_size(void);
 131 extern const struct nla_policy nf_ct_port_nla_policy[];
 132
 133 #ifdef CONFIG_SYSCTL
 134 #ifdef DEBUG_INVALID_PACKETS
 135 #define LOG_INVALID(net, proto)                         \
 136         ((net)->ct.sysctl_log_invalid == (proto) ||     \
 137          (net)->ct.sysctl_log_invalid == IPPROTO_RAW)
 138 #else
 139 #define LOG_INVALID(net, proto)                         \
 140         (((net)->ct.sysctl_log_invalid == (proto) ||    \
 141           (net)->ct.sysctl_log_invalid == IPPROTO_RAW)  \
 142          && net_ratelimit())
 143 #endif
 144 #else
 145 static inline int LOG_INVALID(struct net *net, int proto) { return 0; }
 146 #endif /* CONFIG_SYSCTL */
 147
 148 #endif /*_NF_CONNTRACK_PROTOCOL_H*/