include/uapi/linux/netfilter/nfnetlink_compat.h

Source file repositories/reference/linux-study-clean/include/uapi/linux/netfilter/nfnetlink_compat.h

File Facts

System
Linux kernel
Corpus path
include/uapi/linux/netfilter/nfnetlink_compat.h
Extension
.h
Size
2489 bytes
Lines
65
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct nfattr {
	__u16 nfa_len;
	__u16 nfa_type;	/* we use 15 bits for the type, and the highest
				 * bit to indicate whether the payload is nested */
};

/* FIXME: Apart from NFNL_NFA_NESTED shamelessly copy and pasted from
 * rtnetlink.h, it's time to put this in a generic file */

#define NFNL_NFA_NEST	0x8000
#define NFA_TYPE(attr) 	((attr)->nfa_type & 0x7fff)

#define NFA_ALIGNTO     4
#define NFA_ALIGN(len)	(((len) + NFA_ALIGNTO - 1) & ~(NFA_ALIGNTO - 1))
#define NFA_OK(nfa,len)	((len) > 0 && (nfa)->nfa_len >= sizeof(struct nfattr) \
	&& (nfa)->nfa_len <= (len))
#define NFA_NEXT(nfa,attrlen)	((attrlen) -= NFA_ALIGN((nfa)->nfa_len), \
	(struct nfattr *)(((char *)(nfa)) + NFA_ALIGN((nfa)->nfa_len)))
#define NFA_LENGTH(len)	(NFA_ALIGN(sizeof(struct nfattr)) + (len))
#define NFA_SPACE(len)	NFA_ALIGN(NFA_LENGTH(len))
#define NFA_DATA(nfa)   ((void *)(((char *)(nfa)) + NFA_LENGTH(0)))
#define NFA_PAYLOAD(nfa) ((int)((nfa)->nfa_len) - NFA_LENGTH(0))
#define NFA_NEST(skb, type) \
({	struct nfattr *__start = (struct nfattr *)skb_tail_pointer(skb); \
	NFA_PUT(skb, (NFNL_NFA_NEST | type), 0, NULL); \
	__start;  })
#define NFA_NEST_END(skb, start) \
({      (start)->nfa_len = skb_tail_pointer(skb) - (unsigned char *)(start); \
        (skb)->len; })
#define NFA_NEST_CANCEL(skb, start) \
({      if (start) \
                skb_trim(skb, (unsigned char *) (start) - (skb)->data); \
        -1; })

#define NFM_NFA(n)      ((struct nfattr *)(((char *)(n)) \
        + NLMSG_ALIGN(sizeof(struct nfgenmsg))))
#define NFM_PAYLOAD(n)  NLMSG_PAYLOAD(n, sizeof(struct nfgenmsg))

#endif /* ! __KERNEL__ */
#endif /* _NFNETLINK_COMPAT_H */

Annotation

Implementation Notes