include/linux/netfilter/nfnetlink.h

   1 #ifndef _NFNETLINK_H
   2 #define _NFNETLINK_H
   3 #include <linux/types.h>
   4
   5 #ifndef __KERNEL__
   6 /* nfnetlink groups: Up to 32 maximum - backwards compatibility for userspace */
   7 #define NF_NETLINK_CONNTRACK_NEW                0x00000001
   8 #define NF_NETLINK_CONNTRACK_UPDATE             0x00000002
   9 #define NF_NETLINK_CONNTRACK_DESTROY            0x00000004
  10 #define NF_NETLINK_CONNTRACK_EXP_NEW            0x00000008
  11 #define NF_NETLINK_CONNTRACK_EXP_UPDATE         0x00000010
  12 #define NF_NETLINK_CONNTRACK_EXP_DESTROY        0x00000020
  13 #endif
  14
  15 enum nfnetlink_groups {
  16         NFNLGRP_NONE,
  17 #define NFNLGRP_NONE                    NFNLGRP_NONE
  18         NFNLGRP_CONNTRACK_NEW,
  19 #define NFNLGRP_CONNTRACK_NEW           NFNLGRP_CONNTRACK_NEW
  20         NFNLGRP_CONNTRACK_UPDATE,
  21 #define NFNLGRP_CONNTRACK_UPDATE        NFNLGRP_CONNTRACK_UPDATE
  22         NFNLGRP_CONNTRACK_DESTROY,
  23 #define NFNLGRP_CONNTRACK_DESTROY       NFNLGRP_CONNTRACK_DESTROY
  24         NFNLGRP_CONNTRACK_EXP_NEW,
  25 #define NFNLGRP_CONNTRACK_EXP_NEW       NFNLGRP_CONNTRACK_EXP_NEW
  26         NFNLGRP_CONNTRACK_EXP_UPDATE,
  27 #define NFNLGRP_CONNTRACK_EXP_UPDATE    NFNLGRP_CONNTRACK_EXP_UPDATE
  28         NFNLGRP_CONNTRACK_EXP_DESTROY,
  29 #define NFNLGRP_CONNTRACK_EXP_DESTROY   NFNLGRP_CONNTRACK_EXP_DESTROY
  30         __NFNLGRP_MAX,
  31 };
  32 #define NFNLGRP_MAX     (__NFNLGRP_MAX - 1)
  33
  34 /* Generic structure for encapsulation optional netfilter information.
  35  * It is reminiscent of sockaddr, but with sa_family replaced
  36  * with attribute type.
  37  * ! This should someday be put somewhere generic as now rtnetlink and
  38  * ! nfnetlink use the same attributes methods. - J. Schulist.
  39  */
  40
  41 struct nfattr
  42 {
  43         u_int16_t nfa_len;
  44         u_int16_t nfa_type;     /* we use 15 bits for the type, and the highest
  45                                  * bit to indicate whether the payload is nested */
  46 };
  47
  48 /* FIXME: Apart from NFNL_NFA_NESTED shamelessly copy and pasted from
  49  * rtnetlink.h, it's time to put this in a generic file */
  50
  51 #define NFNL_NFA_NEST   0x8000
  52 #define NFA_TYPE(attr)  ((attr)->nfa_type & 0x7fff)
  53
  54 #define NFA_ALIGNTO     4
  55 #define NFA_ALIGN(len)  (((len) + NFA_ALIGNTO - 1) & ~(NFA_ALIGNTO - 1))
  56 #define NFA_OK(nfa,len) ((len) > 0 && (nfa)->nfa_len >= sizeof(struct nfattr) \
  57         && (nfa)->nfa_len <= (len))
  58 #define NFA_NEXT(nfa,attrlen)   ((attrlen) -= NFA_ALIGN((nfa)->nfa_len), \
  59         (struct nfattr *)(((char *)(nfa)) + NFA_ALIGN((nfa)->nfa_len)))
  60 #define NFA_LENGTH(len) (NFA_ALIGN(sizeof(struct nfattr)) + (len))
  61 #define NFA_SPACE(len)  NFA_ALIGN(NFA_LENGTH(len))
  62 #define NFA_DATA(nfa)   ((void *)(((char *)(nfa)) + NFA_LENGTH(0)))
  63 #define NFA_PAYLOAD(nfa) ((int)((nfa)->nfa_len) - NFA_LENGTH(0))
  64 #define NFA_NEST(skb, type) \
  65 ({      struct nfattr *__start = (struct nfattr *) (skb)->tail; \
  66         NFA_PUT(skb, (NFNL_NFA_NEST | type), 0, NULL); \
  67         __start;  })
  68 #define NFA_NEST_END(skb, start) \
  69 ({      (start)->nfa_len = ((skb)->tail - (unsigned char *) (start)); \
  70         (skb)->len; })
  71 #define NFA_NEST_CANCEL(skb, start) \
  72 ({      if (start) \
  73                 skb_trim(skb, (unsigned char *) (start) - (skb)->data); \
  74         -1; })
  75
  76 /* General form of address family dependent message.
  77  */
  78 struct nfgenmsg {
  79         u_int8_t  nfgen_family;         /* AF_xxx */
  80         u_int8_t  version;              /* nfnetlink version */
  81         __be16    res_id;               /* resource id */
  82 };
  83
  84 #define NFNETLINK_V0    0
  85
  86 #define NFM_NFA(n)      ((struct nfattr *)(((char *)(n)) \
  87         + NLMSG_ALIGN(sizeof(struct nfgenmsg))))
  88 #define NFM_PAYLOAD(n)  NLMSG_PAYLOAD(n, sizeof(struct nfgenmsg))
  89
  90 /* netfilter netlink message types are split in two pieces:
  91  * 8 bit subsystem, 8bit operation.
  92  */
  93
  94 #define NFNL_SUBSYS_ID(x)       ((x & 0xff00) >> 8)
  95 #define NFNL_MSG_TYPE(x)        (x & 0x00ff)
  96
  97 /* No enum here, otherwise __stringify() trick of MODULE_ALIAS_NFNL_SUBSYS()
  98  * won't work anymore */
  99 #define NFNL_SUBSYS_NONE                0
 100 #define NFNL_SUBSYS_CTNETLINK           1
 101 #define NFNL_SUBSYS_CTNETLINK_EXP       2
 102 #define NFNL_SUBSYS_QUEUE               3
 103 #define NFNL_SUBSYS_ULOG                4
 104 #define NFNL_SUBSYS_COUNT               5
 105
 106 #ifdef __KERNEL__
 107
 108 #include <linux/netlink.h>
 109 #include <linux/capability.h>
 110
 111 struct nfnl_callback
 112 {
 113         int (*call)(struct sock *nl, struct sk_buff *skb,
 114                 struct nlmsghdr *nlh, struct nfattr *cda[], int *errp);
 115         u_int16_t attr_count;   /* number of nfattr's */
 116 };
 117
 118 struct nfnetlink_subsystem
 119 {
 120         const char *name;
 121         __u8 subsys_id;         /* nfnetlink subsystem ID */
 122         __u8 cb_count;          /* number of callbacks */
 123         struct nfnl_callback *cb; /* callback for individual types */
 124 };
 125
 126 extern void __nfa_fill(struct sk_buff *skb, int attrtype,
 127         int attrlen, const void *data);
 128 #define NFA_PUT(skb, attrtype, attrlen, data) \
 129 ({ if (skb_tailroom(skb) < (int)NFA_SPACE(attrlen)) goto nfattr_failure; \
 130    __nfa_fill(skb, attrtype, attrlen, data); })
 131
 132 extern struct semaphore nfnl_sem;
 133
 134 #define nfnl_shlock()           down(&nfnl_sem)
 135 #define nfnl_shlock_nowait()    down_trylock(&nfnl_sem)
 136
 137 #define nfnl_shunlock()         do { up(&nfnl_sem); \
 138                                      if(nfnl && nfnl->sk_receive_queue.qlen) \
 139                                             nfnl->sk_data_ready(nfnl, 0); \
 140                                 } while(0)
 141
 142 extern void nfnl_lock(void);
 143 extern void nfnl_unlock(void);
 144
 145 extern int nfnetlink_subsys_register(struct nfnetlink_subsystem *n);
 146 extern int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n);
 147
 148 extern void nfattr_parse(struct nfattr *tb[], int maxattr,
 149                         struct nfattr *nfa, int len);
 150
 151 #define nfattr_parse_nested(tb, max, nfa) \
 152         nfattr_parse((tb), (max), NFA_DATA((nfa)), NFA_PAYLOAD((nfa)))
 153
 154 #define nfattr_bad_size(tb, max, cta_min)                               \
 155 ({      int __i, __res = 0;                                             \
 156         for (__i=0; __i<max; __i++) {                                   \
 157                 if (!cta_min[__i])                                      \
 158                         continue;                                       \
 159                 if (tb[__i] && NFA_PAYLOAD(tb[__i]) < cta_min[__i]){    \
 160                         __res = 1;                                      \
 161                         break;                                          \
 162                 }                                                       \
 163         }                                                               \
 164         __res;                                                          \
 165 })
 166
 167 extern int nfnetlink_has_listeners(unsigned int group);
 168 extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group,
 169                           int echo);
 170 extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags);
 171
 172 #define MODULE_ALIAS_NFNL_SUBSYS(subsys) \
 173         MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys))
 174
 175 #endif  /* __KERNEL__ */
 176 #endif  /* _NFNETLINK_H */