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1 | .TH libnetlink 3 |
2 | .SH NAME | |
3 | libnetlink \- A library for accessing the netlink service | |
4 | .SH SYNOPSIS | |
5 | .nf | |
6 | #include <asm/types.h> | |
7 | .br | |
8 | #include <libnetlink.h> | |
9 | .br | |
10 | #include <linux/netlink.h> | |
11 | .br | |
12 | #include <linux/rtnetlink.h> | |
13 | .sp | |
14 | int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions) | |
15 | .sp | |
16 | int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type) | |
17 | .sp | |
18 | int rtnl_send(struct rtnl_handle *rth, char *buf, int len) | |
19 | .sp | |
20 | int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) | |
21 | .sp | |
22 | int rtnl_dump_filter(struct rtnl_handle *rth, | |
23 | int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *), | |
24 | void *arg1, | |
25 | int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
26 | void *arg2) | |
27 | .sp | |
28 | int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer, | |
29 | unsigned groups, struct nlmsghdr *answer, | |
30 | .br | |
31 | int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
32 | .br | |
33 | void *jarg) | |
34 | .sp | |
35 | int rtnl_listen(struct rtnl_handle *rtnl, | |
36 | int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
37 | void *jarg) | |
38 | .sp | |
39 | int rtnl_from_file(FILE *rtnl, | |
40 | int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
41 | void *jarg) | |
42 | .sp | |
43 | int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data) | |
44 | .sp | |
45 | int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen) | |
46 | .sp | |
47 | int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data) | |
48 | .sp | |
49 | int rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen) | |
50 | .SH DESCRIPTION | |
51 | libnetlink provides a higher level interface to | |
52 | .BR rtnetlink(7). | |
53 | The read functions return 0 on success and a negative errno on failure. | |
54 | The send functions return the amount of data sent, or -1 on error. | |
55 | .TP | |
56 | rtnl_open | |
57 | Open a rtnetlink socket and save the state into the | |
58 | .B rth | |
59 | handle. This handle is passed to all subsequent calls. | |
60 | .B subscriptions | |
61 | is a bitmap of the rtnetlink multicast groups the socket will be | |
62 | a member of. | |
63 | ||
64 | .TP | |
65 | rtnl_wilddump_request | |
66 | Request a full dump of the | |
67 | .B type | |
68 | database for | |
69 | .B family | |
70 | addresses. | |
71 | .B type | |
72 | is a rtnetlink message type. | |
73 | .\" XXX | |
74 | ||
75 | .TP | |
76 | rtnl_dump_request | |
77 | Request a full dump of the | |
78 | .B type | |
79 | data buffer into | |
80 | .B buf | |
81 | with maximum length of | |
82 | .B len. | |
83 | .B type | |
84 | is a rtnetlink message type. | |
85 | ||
86 | .TP | |
87 | rtnl_dump_filter | |
88 | Receive netlink data after a request and filter it. | |
89 | The | |
90 | .B filter | |
91 | callback checks if the received message is wanted. It gets the source | |
92 | address of the message, the message itself and | |
93 | .B arg1 | |
94 | as arguments. 0 as return means that the filter passed, a negative | |
95 | value is returned | |
96 | by | |
97 | .I rtnl_dump_filter | |
98 | in case of error. NULL for | |
99 | .I filter | |
100 | means to not use a filter. | |
101 | .B junk | |
102 | is used to filter messages not destined to the local socket. | |
103 | Only one message bundle is received. Unless there is no message | |
104 | pending, this function does not block. | |
105 | ||
106 | .TP | |
107 | rtnl_listen | |
108 | Receive netlink data after a request and pass it to | |
109 | .I handler. | |
110 | .B handler | |
111 | is a callback that gets the message source address, the message itself, | |
112 | and the | |
113 | .B jarg | |
114 | cookie as arguments. It will get called for all received messages. | |
115 | Only one message bundle is received. Unless there is no message | |
116 | pending this function does not block. | |
117 | ||
118 | .TP | |
119 | rtnl_from_file | |
120 | Works like | |
121 | .I rtnl_listen, | |
122 | but reads a netlink message bundle from the file | |
123 | .B file | |
124 | and passes the messages to | |
125 | .B handler | |
126 | for parsing. The file contains raw data as received from a rtnetlink socket. | |
127 | .PP | |
128 | The following functions are useful to construct custom rtnetlink messages. For | |
129 | simple database dumping with filtering it is better to use the higher level | |
130 | functions above. See | |
131 | .BR rtnetlink(3) | |
132 | and | |
133 | .BR netlink(3) | |
134 | on how to generate a rtnetlink message. The following utility functions | |
135 | require a continuous buffer that already contains a netlink message header | |
136 | and a rtnetlink request. | |
137 | ||
138 | .TP | |
139 | rtnl_send | |
140 | Send the rtnetlink message in | |
141 | .B buf | |
142 | of length | |
143 | .B len | |
144 | to handle | |
145 | .B rth. | |
146 | ||
147 | .TP | |
148 | addattr32 | |
149 | Add a __u32 attribute of type | |
150 | .B type | |
151 | and with value | |
152 | .B data | |
153 | to netlink message | |
154 | .B n, | |
155 | which is part of a buffer of length | |
156 | .B maxlen. | |
157 | ||
158 | .TP | |
159 | addattr_l | |
160 | Add a variable length attribute of type | |
161 | .B type | |
162 | and with value | |
163 | .B data | |
164 | and | |
165 | .B alen | |
166 | length to netlink message | |
167 | .B n, | |
168 | which is part of a buffer of length | |
169 | .B maxlen. | |
170 | .B data | |
171 | is copied. | |
172 | ||
173 | .TP | |
174 | rta_addattr32 | |
175 | Initialize the rtnetlink attribute | |
176 | .B rta | |
177 | with a __u32 data value. | |
178 | ||
179 | .TP | |
180 | rta_addattr32 | |
181 | Initialize the rtnetlink attribute | |
182 | .B rta | |
183 | with a variable length data value. | |
184 | ||
185 | .SH BUGS | |
186 | The functions sometimes use fprintf and exit when a fatal error occurs. | |
187 | This library should be named librtnetlink. | |
188 | ||
189 | .SH AUTHORS | |
190 | netlink/rtnetlink was designed and writen by Alexey Kuznetsov. | |
191 | Andi Kleen wrote the man page. | |
192 | ||
193 | .SH SEE ALSO | |
194 | .BR netlink(7), | |
195 | .BR rtnetlink(7) | |
196 | .br | |
197 | /usr/include/linux/rtnetlink.h |