1/* libnfnetlink.h: Header file for generic netfilter netlink interface
2 *
3 * (C) 2002 Harald Welte <laforge@gnumonks.org>
4 *
5 * 2005-10-29 Pablo Neira Ayuso <pablo@netfilter.org>:
6 * 	Fix NFNL_HEADER_LEN
7 * 2005-11-13 Pablo Neira Ayuso <pablo@netfilter.org>:
8 * 	Define NETLINK_NETFILTER if it's undefined
9 */
10
11#ifndef __LIBNFNETLINK_H
12#define __LIBNFNETLINK_H
13
14#ifndef aligned_u64
15#define aligned_u64 unsigned long long __attribute__((aligned(8)))
16#endif
17
18#include <sys/socket.h>	/* for sa_family_t */
19#include <linux/netlink.h>
20#include <libnfnetlink/linux_nfnetlink.h>
21
22#ifndef NETLINK_NETFILTER
23#define NETLINK_NETFILTER 12
24#endif
25
26#ifndef SOL_NETLINK
27#define SOL_NETLINK	270
28#endif
29
30#ifndef NETLINK_BROADCAST_SEND_ERROR
31#define NETLINK_BROADCAST_SEND_ERROR 4
32#endif
33
34#ifndef NETLINK_NO_ENOBUFS
35#define NETLINK_NO_ENOBUFS 5
36#endif
37
38#define NLMSG_TAIL(nlh) \
39	(((void *) (nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len))
40
41#define NFNL_HEADER_LEN	(NLMSG_ALIGN(sizeof(struct nlmsghdr))	\
42			 +NLMSG_ALIGN(sizeof(struct nfgenmsg)))
43
44#define NFNL_BUFFSIZE		8192
45
46#ifdef __cplusplus
47extern "C" {
48#endif
49
50struct nfnlhdr {
51	struct nlmsghdr nlh;
52	struct nfgenmsg nfmsg;
53};
54
55struct nfnl_callback {
56	int (*call)(struct nlmsghdr *nlh, struct nfattr *nfa[], void *data);
57	void *data;
58	u_int16_t attr_count;
59};
60
61struct nfnl_handle;
62struct nfnl_subsys_handle;
63
64extern int nfnl_fd(struct nfnl_handle *h);
65extern unsigned int nfnl_portid(const struct nfnl_handle *h);
66
67/* get a new library handle */
68extern struct nfnl_handle *nfnl_open(void);
69extern int nfnl_close(struct nfnl_handle *);
70
71extern struct nfnl_subsys_handle *nfnl_subsys_open(struct nfnl_handle *,
72						   u_int8_t, u_int8_t,
73						   unsigned int);
74extern void nfnl_subsys_close(struct nfnl_subsys_handle *);
75
76/* set and unset sequence tracking */
77void nfnl_set_sequence_tracking(struct nfnl_handle *h);
78void nfnl_unset_sequence_tracking(struct nfnl_handle *h);
79
80/* set receive buffer size (for nfnl_catch) */
81extern void nfnl_set_rcv_buffer_size(struct nfnl_handle *h, unsigned int size);
82
83/* sending of data */
84extern int nfnl_send(struct nfnl_handle *, struct nlmsghdr *);
85extern int nfnl_sendmsg(const struct nfnl_handle *, const struct msghdr *msg,
86			unsigned int flags);
87extern int nfnl_sendiov(const struct nfnl_handle *nfnlh,
88			const struct iovec *iov, unsigned int num,
89			unsigned int flags);
90extern void nfnl_fill_hdr(struct nfnl_subsys_handle *, struct nlmsghdr *,
91			  unsigned int, u_int8_t, u_int16_t, u_int16_t,
92			  u_int16_t);
93extern __attribute__((deprecated)) int
94nfnl_talk(struct nfnl_handle *, struct nlmsghdr *, pid_t,
95          unsigned, struct nlmsghdr *,
96          int (*)(struct sockaddr_nl *, struct nlmsghdr *, void *), void *);
97
98/* simple challenge/response */
99extern __attribute__((deprecated)) int
100nfnl_listen(struct nfnl_handle *,
101            int (*)(struct sockaddr_nl *, struct nlmsghdr *, void *), void *);
102
103/* receiving */
104extern ssize_t nfnl_recv(const struct nfnl_handle *h, unsigned char *buf, size_t len);
105extern int nfnl_callback_register(struct nfnl_subsys_handle *,
106				  u_int8_t type, struct nfnl_callback *cb);
107extern int nfnl_callback_unregister(struct nfnl_subsys_handle *, u_int8_t type);
108extern int nfnl_handle_packet(struct nfnl_handle *, char *buf, int len);
109
110/* parsing */
111extern struct nfattr *nfnl_parse_hdr(const struct nfnl_handle *nfnlh,
112				     const struct nlmsghdr *nlh,
113				     struct nfgenmsg **genmsg);
114extern int nfnl_check_attributes(const struct nfnl_handle *nfnlh,
115				 const struct nlmsghdr *nlh,
116				 struct nfattr *tb[]);
117extern struct nlmsghdr *nfnl_get_msg_first(struct nfnl_handle *h,
118					   const unsigned char *buf,
119					   size_t len);
120extern struct nlmsghdr *nfnl_get_msg_next(struct nfnl_handle *h,
121					  const unsigned char *buf,
122					  size_t len);
123
124/* callback verdict */
125enum {
126	NFNL_CB_FAILURE = -1,   /* failure */
127	NFNL_CB_STOP = 0,       /* stop the query */
128	NFNL_CB_CONTINUE = 1,   /* keep iterating */
129};
130
131/* join a certain netlink multicast group */
132extern int nfnl_join(const struct nfnl_handle *nfnlh, unsigned int group);
133
134/* process a netlink message */
135extern int nfnl_process(struct nfnl_handle *h,
136			const unsigned char *buf,
137			size_t len);
138
139/* iterator API */
140
141extern struct nfnl_iterator *
142nfnl_iterator_create(const struct nfnl_handle *h,
143		     const char *buf,
144		     size_t len);
145
146extern void nfnl_iterator_destroy(struct nfnl_iterator *it);
147
148extern int nfnl_iterator_process(struct nfnl_handle *h,
149				 struct nfnl_iterator *it);
150
151extern int nfnl_iterator_next(const struct nfnl_handle *h,
152			      struct nfnl_iterator *it);
153
154/* replacement for nfnl_listen */
155extern int nfnl_catch(struct nfnl_handle *h);
156
157/* replacement for nfnl_talk */
158extern int nfnl_query(struct nfnl_handle *h, struct nlmsghdr *nlh);
159
160#define nfnl_attr_present(tb, attr)			\
161	(tb[attr-1])
162
163#define nfnl_get_data(tb, attr, type)			\
164	({	type __ret = 0;				\
165	 if (tb[attr-1])				\
166	 __ret = *(type *)NFA_DATA(tb[attr-1]);		\
167	 __ret;						\
168	 })
169
170#define nfnl_get_pointer_to_data(tb, attr, type)	\
171	({	type *__ret = NULL;			\
172	 if (tb[attr-1])				\
173	 __ret = NFA_DATA(tb[attr-1]);			\
174	 __ret;						\
175	 })
176
177#ifndef NLA_F_NESTED
178#define NLA_F_NESTED            (1 << 15)
179#endif
180
181/* nfnl attribute handling functions */
182extern int nfnl_addattr_l(struct nlmsghdr *, int, int, const void *, int);
183extern int nfnl_addattr8(struct nlmsghdr *, int, int, u_int8_t);
184extern int nfnl_addattr16(struct nlmsghdr *, int, int, u_int16_t);
185extern int nfnl_addattr32(struct nlmsghdr *, int, int, u_int32_t);
186extern int nfnl_nfa_addattr_l(struct nfattr *, int, int, const void *, int);
187extern int nfnl_nfa_addattr16(struct nfattr *, int, int, u_int16_t);
188extern int nfnl_nfa_addattr32(struct nfattr *, int, int, u_int32_t);
189extern int nfnl_parse_attr(struct nfattr **, int, struct nfattr *, int);
190#define nfnl_parse_nested(tb, max, nfa) \
191	nfnl_parse_attr((tb), (max), NFA_DATA((nfa)), NFA_PAYLOAD((nfa)))
192#define nfnl_nest(nlh, bufsize, type) 				\
193({	struct nfattr *__start = NLMSG_TAIL(nlh);		\
194	nfnl_addattr_l(nlh, bufsize, (NLA_F_NESTED | type), NULL, 0); 	\
195	__start; })
196#define nfnl_nest_end(nlh, tail) 				\
197({	(tail)->nfa_len = (void *) NLMSG_TAIL(nlh) - (void *) tail; })
198
199extern void nfnl_build_nfa_iovec(struct iovec *iov, struct nfattr *nfa,
200				 u_int16_t type, u_int32_t len,
201				 unsigned char *val);
202extern unsigned int nfnl_rcvbufsiz(const struct nfnl_handle *h,
203				   unsigned int size);
204
205
206extern void nfnl_dump_packet(struct nlmsghdr *, int, char *);
207
208/*
209 * index to interface name API
210 */
211
212#ifndef IFNAMSIZ
213#define IFNAMSIZ 16
214#endif
215
216struct nlif_handle;
217
218struct nlif_handle *nlif_open(void);
219void nlif_close(struct nlif_handle *orig);
220int nlif_fd(struct nlif_handle *nlif_handle);
221int nlif_query(struct nlif_handle *nlif_handle);
222int nlif_catch(struct nlif_handle *nlif_handle);
223int nlif_index2name(struct nlif_handle *nlif_handle,
224		    unsigned int if_index,
225		    char *name);
226int nlif_get_ifflags(const struct nlif_handle *h,
227		     unsigned int index,
228		     unsigned int *flags);
229
230#ifdef __cplusplus
231} /* extern "C" */
232#endif
233
234/* Pablo: What is the equivalence of be64_to_cpu in userspace?
235 *
236 * Harald: Good question.  I don't think there's a standard way [yet?],
237 * so I'd suggest manually implementing it by "#if little endian" bitshift
238 * operations in C (at least for now).
239 *
240 * All the payload of any nfattr will always be in network byte order.
241 * This would allow easy transport over a real network in the future
242 * (e.g. jamal's netlink2).
243 *
244 * Pablo: I've called it __be64_to_cpu instead of be64_to_cpu, since maybe
245 * there will one in the userspace headers someday. We don't want to
246 * pollute POSIX space naming,
247 */
248
249#include <byteswap.h>
250#if __BYTE_ORDER == __BIG_ENDIAN
251#  ifndef __be64_to_cpu
252#  define __be64_to_cpu(x)	(x)
253#  endif
254# else
255# if __BYTE_ORDER == __LITTLE_ENDIAN
256#  ifndef __be64_to_cpu
257#  define __be64_to_cpu(x)	__bswap_64(x)
258#  endif
259# endif
260#endif
261
262#endif /* __LIBNFNETLINK_H */
263