Commit | Line | Data |
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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef __LINUX_NETLINK_H |
3 | #define __LINUX_NETLINK_H | |
4 | ||
1da177e4 LT |
5 | |
6 | #include <linux/capability.h> | |
7 | #include <linux/skbuff.h> | |
abb17e6c | 8 | #include <linux/export.h> |
dbe9a417 | 9 | #include <net/scm.h> |
607ca46e | 10 | #include <uapi/linux/netlink.h> |
1da177e4 | 11 | |
56b49f4b OW |
12 | struct net; |
13 | ||
7e3ce05e MRL |
14 | void do_trace_netlink_extack(const char *msg); |
15 | ||
b529ccf2 ACM |
16 | static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb) |
17 | { | |
18 | return (struct nlmsghdr *)skb->data; | |
19 | } | |
20 | ||
9652e931 | 21 | enum netlink_skb_flags { |
2d7a85f4 | 22 | NETLINK_SKB_DST = 0x8, /* Dst set in sendto or sendmsg */ |
9652e931 PM |
23 | }; |
24 | ||
d94d9fee | 25 | struct netlink_skb_parms { |
dbe9a417 | 26 | struct scm_creds creds; /* Skb credentials */ |
15e47304 | 27 | __u32 portid; |
d629b836 | 28 | __u32 dst_group; |
9652e931 | 29 | __u32 flags; |
e32123e5 | 30 | struct sock *sk; |
59324cf3 ND |
31 | bool nsid_is_set; |
32 | int nsid; | |
1da177e4 LT |
33 | }; |
34 | ||
35 | #define NETLINK_CB(skb) (*(struct netlink_skb_parms*)&((skb)->cb)) | |
36 | #define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds) | |
37 | ||
38 | ||
aa9d6e0f SH |
39 | void netlink_table_grab(void); |
40 | void netlink_table_ungrab(void); | |
d136f1bd | 41 | |
9785e10a PNA |
42 | #define NL_CFG_F_NONROOT_RECV (1 << 0) |
43 | #define NL_CFG_F_NONROOT_SEND (1 << 1) | |
44 | ||
a31f2d17 PNA |
45 | /* optional Netlink kernel configuration parameters */ |
46 | struct netlink_kernel_cfg { | |
47 | unsigned int groups; | |
c9d2ea96 | 48 | unsigned int flags; |
a31f2d17 PNA |
49 | void (*input)(struct sk_buff *skb); |
50 | struct mutex *cb_mutex; | |
023e2cfa JB |
51 | int (*bind)(struct net *net, int group); |
52 | void (*unbind)(struct net *net, int group); | |
a31f2d17 PNA |
53 | }; |
54 | ||
aa9d6e0f | 55 | struct sock *__netlink_kernel_create(struct net *net, int unit, |
9f00d977 PNA |
56 | struct module *module, |
57 | struct netlink_kernel_cfg *cfg); | |
58 | static inline struct sock * | |
59 | netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg) | |
60 | { | |
61 | return __netlink_kernel_create(net, unit, THIS_MODULE, cfg); | |
62 | } | |
63 | ||
ba0dc5f6 JB |
64 | /* this can be increased when necessary - don't expose to userland */ |
65 | #define NETLINK_MAX_COOKIE_LEN 20 | |
51c352bd | 66 | #define NETLINK_MAX_FMTMSG_LEN 80 |
ba0dc5f6 | 67 | |
2d4bc933 JB |
68 | /** |
69 | * struct netlink_ext_ack - netlink extended ACK report struct | |
70 | * @_msg: message string to report - don't access directly, use | |
71 | * %NL_SET_ERR_MSG | |
72 | * @bad_attr: attribute with error | |
44f3625b | 73 | * @policy: policy for a bad attribute |
690252f1 JK |
74 | * @miss_type: attribute type which was missing |
75 | * @miss_nest: nest missing an attribute (%NULL if missing top level attr) | |
ba0dc5f6 JB |
76 | * @cookie: cookie data to return to userspace (for success) |
77 | * @cookie_len: actual cookie data length | |
51c352bd EC |
78 | * @_msg_buf: output buffer for formatted message strings - don't access |
79 | * directly, use %NL_SET_ERR_MSG_FMT | |
2d4bc933 JB |
80 | */ |
81 | struct netlink_ext_ack { | |
82 | const char *_msg; | |
83 | const struct nlattr *bad_attr; | |
44f3625b | 84 | const struct nla_policy *policy; |
690252f1 JK |
85 | const struct nlattr *miss_nest; |
86 | u16 miss_type; | |
ba0dc5f6 JB |
87 | u8 cookie[NETLINK_MAX_COOKIE_LEN]; |
88 | u8 cookie_len; | |
51c352bd | 89 | char _msg_buf[NETLINK_MAX_FMTMSG_LEN]; |
2d4bc933 JB |
90 | }; |
91 | ||
92 | /* Always use this macro, this allows later putting the | |
93 | * message into a separate section or such for things | |
94 | * like translation or listing all possible messages. | |
51c352bd | 95 | * If string formatting is needed use NL_SET_ERR_MSG_FMT. |
2d4bc933 | 96 | */ |
4d463c4d | 97 | #define NL_SET_ERR_MSG(extack, msg) do { \ |
6311b7ce | 98 | static const char __msg[] = msg; \ |
4d463c4d DB |
99 | struct netlink_ext_ack *__extack = (extack); \ |
100 | \ | |
7e3ce05e MRL |
101 | do_trace_netlink_extack(__msg); \ |
102 | \ | |
4d463c4d DB |
103 | if (__extack) \ |
104 | __extack->_msg = __msg; \ | |
2d4bc933 JB |
105 | } while (0) |
106 | ||
51c352bd EC |
107 | /* We splice fmt with %s at each end even in the snprintf so that both calls |
108 | * can use the same string constant, avoiding its duplication in .ro | |
109 | */ | |
110 | #define NL_SET_ERR_MSG_FMT(extack, fmt, args...) do { \ | |
111 | struct netlink_ext_ack *__extack = (extack); \ | |
112 | \ | |
113 | if (!__extack) \ | |
114 | break; \ | |
115 | if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \ | |
116 | "%s" fmt "%s", "", ##args, "") >= \ | |
117 | NETLINK_MAX_FMTMSG_LEN) \ | |
118 | net_warn_ratelimited("%s" fmt "%s", "truncated extack: ", \ | |
119 | ##args, "\n"); \ | |
120 | \ | |
121 | do_trace_netlink_extack(__extack->_msg_buf); \ | |
122 | \ | |
123 | __extack->_msg = __extack->_msg_buf; \ | |
124 | } while (0) | |
125 | ||
4d463c4d DB |
126 | #define NL_SET_ERR_MSG_MOD(extack, msg) \ |
127 | NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg) | |
45d9b378 | 128 | |
51c352bd EC |
129 | #define NL_SET_ERR_MSG_FMT_MOD(extack, fmt, args...) \ |
130 | NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args) | |
131 | ||
028fb19c LR |
132 | #define NL_SET_ERR_MSG_WEAK(extack, msg) do { \ |
133 | if ((extack) && !(extack)->_msg) \ | |
134 | NL_SET_ERR_MSG((extack), msg); \ | |
135 | } while (0) | |
136 | ||
137 | #define NL_SET_ERR_MSG_WEAK_MOD(extack, msg) do { \ | |
138 | if ((extack) && !(extack)->_msg) \ | |
139 | NL_SET_ERR_MSG_MOD((extack), msg); \ | |
140 | } while (0) | |
141 | ||
44f3625b JB |
142 | #define NL_SET_BAD_ATTR_POLICY(extack, attr, pol) do { \ |
143 | if ((extack)) { \ | |
c3ab2b4e | 144 | (extack)->bad_attr = (attr); \ |
44f3625b JB |
145 | (extack)->policy = (pol); \ |
146 | } \ | |
c3ab2b4e DA |
147 | } while (0) |
148 | ||
44f3625b JB |
149 | #define NL_SET_BAD_ATTR(extack, attr) NL_SET_BAD_ATTR_POLICY(extack, attr, NULL) |
150 | ||
151 | #define NL_SET_ERR_MSG_ATTR_POL(extack, attr, pol, msg) do { \ | |
152 | static const char __msg[] = msg; \ | |
153 | struct netlink_ext_ack *__extack = (extack); \ | |
154 | \ | |
7e3ce05e MRL |
155 | do_trace_netlink_extack(__msg); \ |
156 | \ | |
44f3625b JB |
157 | if (__extack) { \ |
158 | __extack->_msg = __msg; \ | |
159 | __extack->bad_attr = (attr); \ | |
160 | __extack->policy = (pol); \ | |
161 | } \ | |
9ae28727 DA |
162 | } while (0) |
163 | ||
3e4d5ba9 SA |
164 | #define NL_SET_ERR_MSG_ATTR_POL_FMT(extack, attr, pol, fmt, args...) do { \ |
165 | struct netlink_ext_ack *__extack = (extack); \ | |
166 | \ | |
167 | if (!__extack) \ | |
168 | break; \ | |
169 | \ | |
170 | if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \ | |
171 | "%s" fmt "%s", "", ##args, "") >= \ | |
172 | NETLINK_MAX_FMTMSG_LEN) \ | |
173 | net_warn_ratelimited("%s" fmt "%s", "truncated extack: ", \ | |
174 | ##args, "\n"); \ | |
175 | \ | |
176 | do_trace_netlink_extack(__extack->_msg_buf); \ | |
177 | \ | |
178 | __extack->_msg = __extack->_msg_buf; \ | |
179 | __extack->bad_attr = (attr); \ | |
180 | __extack->policy = (pol); \ | |
181 | } while (0) | |
182 | ||
44f3625b JB |
183 | #define NL_SET_ERR_MSG_ATTR(extack, attr, msg) \ |
184 | NL_SET_ERR_MSG_ATTR_POL(extack, attr, NULL, msg) | |
185 | ||
3e4d5ba9 SA |
186 | #define NL_SET_ERR_MSG_ATTR_FMT(extack, attr, msg, args...) \ |
187 | NL_SET_ERR_MSG_ATTR_POL_FMT(extack, attr, NULL, msg, ##args) | |
188 | ||
690252f1 JK |
189 | #define NL_SET_ERR_ATTR_MISS(extack, nest, type) do { \ |
190 | struct netlink_ext_ack *__extack = (extack); \ | |
191 | \ | |
192 | if (__extack) { \ | |
193 | __extack->miss_nest = (nest); \ | |
194 | __extack->miss_type = (type); \ | |
195 | } \ | |
196 | } while (0) | |
197 | ||
45dca157 JK |
198 | #define NL_REQ_ATTR_CHECK(extack, nest, tb, type) ({ \ |
199 | struct nlattr **__tb = (tb); \ | |
200 | u32 __attr = (type); \ | |
201 | int __retval; \ | |
202 | \ | |
203 | __retval = !__tb[__attr]; \ | |
204 | if (__retval) \ | |
205 | NL_SET_ERR_ATTR_MISS((extack), (nest), __attr); \ | |
206 | __retval; \ | |
207 | }) | |
208 | ||
801f8746 JB |
209 | static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack, |
210 | u64 cookie) | |
211 | { | |
55b474c4 MK |
212 | if (!extack) |
213 | return; | |
c6400e3f AD |
214 | memcpy(extack->cookie, &cookie, sizeof(cookie)); |
215 | extack->cookie_len = sizeof(cookie); | |
801f8746 JB |
216 | } |
217 | ||
aa9d6e0f SH |
218 | void netlink_kernel_release(struct sock *sk); |
219 | int __netlink_change_ngroups(struct sock *sk, unsigned int groups); | |
220 | int netlink_change_ngroups(struct sock *sk, unsigned int groups); | |
221 | void __netlink_clear_multicast_users(struct sock *sk, unsigned int group); | |
222 | void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, | |
223 | const struct netlink_ext_ack *extack); | |
224 | int netlink_has_listeners(struct sock *sk, unsigned int group); | |
59c28058 | 225 | bool netlink_strict_get_check(struct sk_buff *skb); |
aa9d6e0f SH |
226 | |
227 | int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock); | |
228 | int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid, | |
229 | __u32 group, gfp_t allocation); | |
aa9d6e0f SH |
230 | int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code); |
231 | int netlink_register_notifier(struct notifier_block *nb); | |
232 | int netlink_unregister_notifier(struct notifier_block *nb); | |
1da177e4 LT |
233 | |
234 | /* finegrained unicast helpers: */ | |
235 | struct sock *netlink_getsockbyfilp(struct file *filp); | |
9457afee | 236 | int netlink_attachskb(struct sock *sk, struct sk_buff *skb, |
c3d8d1e3 | 237 | long *timeo, struct sock *ssk); |
1da177e4 | 238 | void netlink_detachskb(struct sock *sk, struct sk_buff *skb); |
7ee015e0 | 239 | int netlink_sendskb(struct sock *sk, struct sk_buff *skb); |
1da177e4 | 240 | |
3a36515f PN |
241 | static inline struct sk_buff * |
242 | netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask) | |
243 | { | |
244 | struct sk_buff *nskb; | |
245 | ||
246 | nskb = skb_clone(skb, gfp_mask); | |
247 | if (!nskb) | |
248 | return NULL; | |
249 | ||
250 | /* This is a large skb, set destructor callback to release head */ | |
251 | if (is_vmalloc_addr(skb->head)) | |
252 | nskb->destructor = skb->destructor; | |
253 | ||
254 | return nskb; | |
255 | } | |
256 | ||
1da177e4 LT |
257 | /* |
258 | * skb should fit one page. This choice is good for headerless malloc. | |
fc910a27 DM |
259 | * But we should limit to 8K so that userspace does not have to |
260 | * use enormous buffer sizes on recvmsg() calls just to avoid | |
261 | * MSG_TRUNC when PAGE_SIZE is very large. | |
1da177e4 | 262 | */ |
fc910a27 DM |
263 | #if PAGE_SIZE < 8192UL |
264 | #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE) | |
265 | #else | |
266 | #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL) | |
267 | #endif | |
268 | ||
339bf98f | 269 | #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN) |
1da177e4 LT |
270 | |
271 | ||
d94d9fee | 272 | struct netlink_callback { |
3a6c2b41 PM |
273 | struct sk_buff *skb; |
274 | const struct nlmsghdr *nlh; | |
275 | int (*dump)(struct sk_buff * skb, | |
276 | struct netlink_callback *cb); | |
277 | int (*done)(struct netlink_callback *cb); | |
7175c883 | 278 | void *data; |
6dc878a8 G |
279 | /* the module that dump function belong to */ |
280 | struct module *module; | |
4a19edb6 | 281 | struct netlink_ext_ack *extack; |
c7ac8679 | 282 | u16 family; |
22e6c58b | 283 | u16 answer_flags; |
085c20ca | 284 | u32 min_dump_alloc; |
670dc283 | 285 | unsigned int prev_seq, seq; |
085c20ca | 286 | bool strict_check; |
362b87f5 JD |
287 | union { |
288 | u8 ctx[48]; | |
289 | ||
290 | /* args is deprecated. Cast a struct over ctx instead | |
291 | * for proper type safety. | |
292 | */ | |
293 | long args[6]; | |
294 | }; | |
1da177e4 LT |
295 | }; |
296 | ||
ec8f7d49 | 297 | #define NL_ASSERT_DUMP_CTX_FITS(type_name) \ |
2c7bc10d JK |
298 | BUILD_BUG_ON(sizeof(type_name) > \ |
299 | sizeof_field(struct netlink_callback, ctx)) | |
300 | ||
d94d9fee | 301 | struct netlink_notify { |
b4b51029 | 302 | struct net *net; |
0392d099 | 303 | u32 portid; |
1da177e4 LT |
304 | int protocol; |
305 | }; | |
306 | ||
a46621a3 | 307 | struct nlmsghdr * |
15e47304 | 308 | __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags); |
1da177e4 | 309 | |
80d326fa | 310 | struct netlink_dump_control { |
fc9e50f5 | 311 | int (*start)(struct netlink_callback *); |
80d326fa | 312 | int (*dump)(struct sk_buff *skb, struct netlink_callback *); |
6dc878a8 | 313 | int (*done)(struct netlink_callback *); |
7175c883 | 314 | void *data; |
6dc878a8 | 315 | struct module *module; |
ebfe3c51 | 316 | u32 min_dump_alloc; |
80d326fa PNA |
317 | }; |
318 | ||
aa9d6e0f | 319 | int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, |
6dc878a8 G |
320 | const struct nlmsghdr *nlh, |
321 | struct netlink_dump_control *control); | |
322 | static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, | |
323 | const struct nlmsghdr *nlh, | |
324 | struct netlink_dump_control *control) | |
325 | { | |
326 | if (!control->module) | |
327 | control->module = THIS_MODULE; | |
328 | ||
329 | return __netlink_dump_start(ssk, skb, nlh, control); | |
330 | } | |
1da177e4 | 331 | |
bcbde0d4 DB |
332 | struct netlink_tap { |
333 | struct net_device *dev; | |
334 | struct module *module; | |
335 | struct list_head list; | |
336 | }; | |
337 | ||
aa9d6e0f SH |
338 | int netlink_add_tap(struct netlink_tap *nt); |
339 | int netlink_remove_tap(struct netlink_tap *nt); | |
bcbde0d4 | 340 | |
aa4cf945 EB |
341 | bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, |
342 | struct user_namespace *ns, int cap); | |
343 | bool netlink_ns_capable(const struct sk_buff *skb, | |
344 | struct user_namespace *ns, int cap); | |
345 | bool netlink_capable(const struct sk_buff *skb, int cap); | |
346 | bool netlink_net_capable(const struct sk_buff *skb, int cap); | |
347 | ||
1da177e4 | 348 | #endif /* __LINUX_NETLINK_H */ |