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;
  45 } __attribute__ ((packed));
  46
  47 /* FIXME: Shamelessly copy and pasted from rtnetlink.h, it's time
  48  *        to put this in a generic file */
  49
  50 #define NFA_ALIGNTO     4
  51 #define NFA_ALIGN(len)  (((len) + NFA_ALIGNTO - 1) & ~(NFA_ALIGNTO - 1))
  52 #define NFA_OK(nfa,len) ((len) > 0 && (nfa)->nfa_len >= sizeof(struct nfattr) \
  53         && (nfa)->nfa_len <= (len))
  54 #define NFA_NEXT(nfa,attrlen)   ((attrlen) -= NFA_ALIGN((nfa)->nfa_len), \
  55         (struct nfattr *)(((char *)(nfa)) + NFA_ALIGN((nfa)->nfa_len)))
  56 #define NFA_LENGTH(len) (NFA_ALIGN(sizeof(struct nfattr)) + (len))
  57 #define NFA_SPACE(len)  NFA_ALIGN(NFA_LENGTH(len))
  58 #define NFA_DATA(nfa)   ((void *)(((char *)(nfa)) + NFA_LENGTH(0)))
  59 #define NFA_PAYLOAD(nfa) ((int)((nfa)->nfa_len) - NFA_LENGTH(0))
  60 #define NFA_NEST(skb, type) \
  61 ({      struct nfattr *__start = (struct nfattr *) (skb)->tail; \
  62         NFA_PUT(skb, type, 0, NULL); \
  63         __start;  })
  64 #define NFA_NEST_END(skb, start) \
  65 ({      (start)->nfa_len = ((skb)->tail - (unsigned char *) (start)); \
  66         (skb)->len; })
  67 #define NFA_NEST_CANCEL(skb, start) \
  68 ({      if (start) \
  69                 skb_trim(skb, (unsigned char *) (start) - (skb)->data); \
  70         -1; })
  71
  72 /* General form of address family dependent message.
  73  */
  74 struct nfgenmsg {
  75         u_int8_t  nfgen_family;         /* AF_xxx */
  76         u_int8_t  version;              /* nfnetlink version */
  77         u_int16_t res_id;               /* resource id */
  78 } __attribute__ ((packed));
  79
  80 #define NFNETLINK_V0    0
  81
  82 #define NFM_NFA(n)      ((struct nfattr *)(((char *)(n)) \
  83         + NLMSG_ALIGN(sizeof(struct nfgenmsg))))
  84 #define NFM_PAYLOAD(n)  NLMSG_PAYLOAD(n, sizeof(struct nfgenmsg))
  85
  86 /* netfilter netlink message types are split in two pieces:
  87  * 8 bit subsystem, 8bit operation.
  88  */
  89
  90 #define NFNL_SUBSYS_ID(x)       ((x & 0xff00) >> 8)
  91 #define NFNL_MSG_TYPE(x)        (x & 0x00ff)
  92
  93 /* No enum here, otherwise __stringify() trick of MODULE_ALIAS_NFNL_SUBSYS()
  94  * won't work anymore */
  95 #define NFNL_SUBSYS_NONE                0
  96 #define NFNL_SUBSYS_CTNETLINK           1
  97 #define NFNL_SUBSYS_CTNETLINK_EXP       2
  98 #define NFNL_SUBSYS_QUEUE               3
  99 #define NFNL_SUBSYS_ULOG                4
 100 #define NFNL_SUBSYS_COUNT               5
 101
 102 #ifdef __KERNEL__
 103
 104 #include <linux/netlink.h>
 105 #include <linux/capability.h>
 106
 107 struct nfnl_callback
 108 {
 109         int (*call)(struct sock *nl, struct sk_buff *skb,
 110                 struct nlmsghdr *nlh, struct nfattr *cda[], int *errp);
 111         kernel_cap_t cap_required; /* capabilities required for this msg */
 112         u_int16_t attr_count;   /* number of nfattr's */
 113 };
 114
 115 struct nfnetlink_subsystem
 116 {
 117         const char *name;
 118         __u8 subsys_id;         /* nfnetlink subsystem ID */
 119         __u8 cb_count;          /* number of callbacks */
 120         struct nfnl_callback *cb; /* callback for individual types */
 121 };
 122
 123 extern void __nfa_fill(struct sk_buff *skb, int attrtype,
 124         int attrlen, const void *data);
 125 #define NFA_PUT(skb, attrtype, attrlen, data) \
 126 ({ if (skb_tailroom(skb) < (int)NFA_SPACE(attrlen)) goto nfattr_failure; \
 127    __nfa_fill(skb, attrtype, attrlen, data); })
 128
 129 extern struct semaphore nfnl_sem;
 130
 131 #define nfnl_shlock()           down(&nfnl_sem)
 132 #define nfnl_shlock_nowait()    down_trylock(&nfnl_sem)
 133
 134 #define nfnl_shunlock()         do { up(&nfnl_sem); \
 135                                      if(nfnl && nfnl->sk_receive_queue.qlen) \
 136                                             nfnl->sk_data_ready(nfnl, 0); \
 137                                 } while(0)
 138
 139 extern void nfnl_lock(void);
 140 extern void nfnl_unlock(void);
 141
 142 extern int nfnetlink_subsys_register(struct nfnetlink_subsystem *n);
 143 extern int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n);
 144
 145 extern int nfattr_parse(struct nfattr *tb[], int maxattr,
 146                         struct nfattr *nfa, int len);
 147
 148 #define nfattr_parse_nested(tb, max, nfa) \
 149         nfattr_parse((tb), (max), NFA_DATA((nfa)), NFA_PAYLOAD((nfa)))
 150
 151 #define nfattr_bad_size(tb, max, cta_min)                               \
 152 ({      int __i, __res = 0;                                             \
 153         for (__i=0; __i<max; __i++)                                     \
 154                 if (tb[__i] && NFA_PAYLOAD(tb[__i]) < cta_min[__i]){    \
 155                         __res = 1;                                      \
 156                         break;                                          \
 157                 }                                                       \
 158         __res;                                                          \
 159 })
 160
 161 extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group,
 162                           int echo);
 163 extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags);
 164
 165 #define MODULE_ALIAS_NFNL_SUBSYS(subsys) \
 166         MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys))
 167
 168 #endif  /* __KERNEL__ */
 169 #endif  /* _NFNETLINK_H */