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1 /* SPDX-License-Identifier: LGPL-2.1-only */
2 /*
3  * Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch>
4  */
5 
6 #ifndef NETLINK_MSG_H_
7 #define NETLINK_MSG_H_
8 
9 #include <netlink/netlink.h>
10 #include <netlink/object.h>
11 #include <netlink/attr.h>
12 
13 #ifdef __cplusplus
14 extern "C" {
15 #endif
16 
17 struct nlmsghdr;
18 
19 #define NL_DONTPAD	0
20 
21 /**
22  * @ingroup msg
23  * @brief
24  * Will cause the netlink port to be set to the port assigned to
25  * the netlink icoket ust before sending the message off.
26  *
27  * @note Requires the use of nl_send_auto()!
28  */
29 #define NL_AUTO_PORT	0
30 #define NL_AUTO_PID	NL_AUTO_PORT
31 
32 /**
33  * @ingroup msg
34  * @brief
35  * May be used to refer to a sequence number which should be
36  * automatically set just before sending the message off.
37  *
38  * @note Requires the use of nl_send_auto()!
39  */
40 #define NL_AUTO_SEQ	0
41 
42 struct nl_msg;
43 struct nl_tree;
44 struct ucred;
45 
46 extern int			nlmsg_size(int);
47 extern int			nlmsg_total_size(int);
48 extern int			nlmsg_padlen(int);
49 
50 extern void *			nlmsg_data(const struct nlmsghdr *);
51 extern int			nlmsg_datalen(const struct nlmsghdr *);
52 extern void *			nlmsg_tail(const struct nlmsghdr *);
53 
54 /* attribute access */
55 extern struct nlattr *	  nlmsg_attrdata(const struct nlmsghdr *, int);
56 extern int		  nlmsg_attrlen(const struct nlmsghdr *, int);
57 
58 /* message parsing */
59 extern int		  nlmsg_valid_hdr(const struct nlmsghdr *, int);
60 extern int		  nlmsg_ok(const struct nlmsghdr *, int);
61 extern struct nlmsghdr *  nlmsg_next(struct nlmsghdr *, int *);
62 extern int		  nlmsg_parse(struct nlmsghdr *, int, struct nlattr **,
63 				      int, const struct nla_policy *);
64 extern struct nlattr *	  nlmsg_find_attr(struct nlmsghdr *, int, int);
65 extern int		  nlmsg_validate(struct nlmsghdr *, int, int,
66 					 const struct nla_policy *);
67 
68 extern struct nl_msg *	  nlmsg_alloc(void);
69 extern struct nl_msg *	  nlmsg_alloc_size(size_t);
70 extern struct nl_msg *	  nlmsg_alloc_simple(int, int);
71 extern void		  nlmsg_set_default_size(size_t);
72 extern struct nl_msg *	  nlmsg_inherit(struct nlmsghdr *);
73 extern struct nl_msg *	  nlmsg_convert(struct nlmsghdr *);
74 extern void *		  nlmsg_reserve(struct nl_msg *, size_t, int);
75 extern int		  nlmsg_append(struct nl_msg *, void *, size_t, int);
76 extern int		  nlmsg_expand(struct nl_msg *, size_t);
77 
78 extern struct nlmsghdr *  nlmsg_put(struct nl_msg *, uint32_t, uint32_t,
79 				    int, int, int);
80 extern struct nlmsghdr *  nlmsg_hdr(struct nl_msg *);
81 extern void		  nlmsg_get(struct nl_msg *);
82 extern void		  nlmsg_free(struct nl_msg *);
83 
84 /* attribute modification */
85 extern void		  nlmsg_set_proto(struct nl_msg *, int);
86 extern int		  nlmsg_get_proto(struct nl_msg *);
87 extern size_t		  nlmsg_get_max_size(struct nl_msg *);
88 extern void		  nlmsg_set_src(struct nl_msg *, struct sockaddr_nl *);
89 extern struct sockaddr_nl *nlmsg_get_src(struct nl_msg *);
90 extern void		  nlmsg_set_dst(struct nl_msg *, struct sockaddr_nl *);
91 extern struct sockaddr_nl *nlmsg_get_dst(struct nl_msg *);
92 extern void		  nlmsg_set_creds(struct nl_msg *, struct ucred *);
93 extern struct ucred *	  nlmsg_get_creds(struct nl_msg *);
94 
95 extern char *		  nl_nlmsgtype2str(int, char *, size_t);
96 extern int		  nl_str2nlmsgtype(const char *);
97 
98 extern char *		  nl_nlmsg_flags2str(int, char *, size_t);
99 
100 extern int		  nl_msg_parse(struct nl_msg *,
101 				       void (*cb)(struct nl_object *, void *),
102 				       void *);
103 
104 extern void		nl_msg_dump(struct nl_msg *, FILE *);
105 
106 /**
107  * @name Iterators
108  * @{
109  */
110 
111 /**
112  * @ingroup msg
113  * Iterate over a stream of attributes in a message
114  * @arg pos	loop counter, set to current attribute
115  * @arg nlh	netlink message header
116  * @arg hdrlen	length of family header
117  * @arg rem	initialized to len, holds bytes currently remaining in stream
118  */
119 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
120 	nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
121 			  nlmsg_attrlen(nlh, hdrlen), rem)
122 
123 /**
124  * Iterate over a stream of messages
125  * @arg pos	loop counter, set to current message
126  * @arg head	head of message stream
127  * @arg len	length of message stream
128  */
129 #define nlmsg_for_each(pos, head, len) \
130 	for (int rem = len, pos = head; \
131 		nlmsg_ok(pos, rem); \
132 		pos = nlmsg_next(pos, &rem))
133 
134 #define nlmsg_for_each_msg(pos, head, len, rem) \
135 		nlmsg_for_each(pos, head, len)
136 
137 /** @} */
138 
139 #ifdef __cplusplus
140 }
141 #endif
142 
143 #endif
144