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      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 } __attribute__ ((packed));
     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 	u_int16_t res_id;		/* resource id */
     82 } __attribute__ ((packed));
     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 */
    177