xref: /openbmc/linux/net/ethtool/netlink.h (revision f8e17c17)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 
3 #ifndef _NET_ETHTOOL_NETLINK_H
4 #define _NET_ETHTOOL_NETLINK_H
5 
6 #include <linux/ethtool_netlink.h>
7 #include <linux/netdevice.h>
8 #include <net/genetlink.h>
9 #include <net/sock.h>
10 
11 struct ethnl_req_info;
12 
13 int ethnl_parse_header(struct ethnl_req_info *req_info,
14 		       const struct nlattr *nest, struct net *net,
15 		       struct netlink_ext_ack *extack, bool require_dev);
16 int ethnl_fill_reply_header(struct sk_buff *skb, struct net_device *dev,
17 			    u16 attrtype);
18 struct sk_buff *ethnl_reply_init(size_t payload, struct net_device *dev, u8 cmd,
19 				 u16 hdr_attrtype, struct genl_info *info,
20 				 void **ehdrp);
21 
22 /**
23  * ethnl_strz_size() - calculate attribute length for fixed size string
24  * @s: ETH_GSTRING_LEN sized string (may not be null terminated)
25  *
26  * Return: total length of an attribute with null terminated string from @s
27  */
28 static inline int ethnl_strz_size(const char *s)
29 {
30 	return nla_total_size(strnlen(s, ETH_GSTRING_LEN) + 1);
31 }
32 
33 /**
34  * ethnl_put_strz() - put string attribute with fixed size string
35  * @skb:     skb with the message
36  * @attrype: attribute type
37  * @s:       ETH_GSTRING_LEN sized string (may not be null terminated)
38  *
39  * Puts an attribute with null terminated string from @s into the message.
40  *
41  * Return: 0 on success, negative error code on failure
42  */
43 static inline int ethnl_put_strz(struct sk_buff *skb, u16 attrtype,
44 				 const char *s)
45 {
46 	unsigned int len = strnlen(s, ETH_GSTRING_LEN);
47 	struct nlattr *attr;
48 
49 	attr = nla_reserve(skb, attrtype, len + 1);
50 	if (!attr)
51 		return -EMSGSIZE;
52 
53 	memcpy(nla_data(attr), s, len);
54 	((char *)nla_data(attr))[len] = '\0';
55 	return 0;
56 }
57 
58 /**
59  * ethnl_update_u32() - update u32 value from NLA_U32 attribute
60  * @dst:  value to update
61  * @attr: netlink attribute with new value or null
62  * @mod:  pointer to bool for modification tracking
63  *
64  * Copy the u32 value from NLA_U32 netlink attribute @attr into variable
65  * pointed to by @dst; do nothing if @attr is null. Bool pointed to by @mod
66  * is set to true if this function changed the value of *dst, otherwise it
67  * is left as is.
68  */
69 static inline void ethnl_update_u32(u32 *dst, const struct nlattr *attr,
70 				    bool *mod)
71 {
72 	u32 val;
73 
74 	if (!attr)
75 		return;
76 	val = nla_get_u32(attr);
77 	if (*dst == val)
78 		return;
79 
80 	*dst = val;
81 	*mod = true;
82 }
83 
84 /**
85  * ethnl_update_u8() - update u8 value from NLA_U8 attribute
86  * @dst:  value to update
87  * @attr: netlink attribute with new value or null
88  * @mod:  pointer to bool for modification tracking
89  *
90  * Copy the u8 value from NLA_U8 netlink attribute @attr into variable
91  * pointed to by @dst; do nothing if @attr is null. Bool pointed to by @mod
92  * is set to true if this function changed the value of *dst, otherwise it
93  * is left as is.
94  */
95 static inline void ethnl_update_u8(u8 *dst, const struct nlattr *attr,
96 				   bool *mod)
97 {
98 	u8 val;
99 
100 	if (!attr)
101 		return;
102 	val = nla_get_u8(attr);
103 	if (*dst == val)
104 		return;
105 
106 	*dst = val;
107 	*mod = true;
108 }
109 
110 /**
111  * ethnl_update_bool32() - update u32 used as bool from NLA_U8 attribute
112  * @dst:  value to update
113  * @attr: netlink attribute with new value or null
114  * @mod:  pointer to bool for modification tracking
115  *
116  * Use the u8 value from NLA_U8 netlink attribute @attr to set u32 variable
117  * pointed to by @dst to 0 (if zero) or 1 (if not); do nothing if @attr is
118  * null. Bool pointed to by @mod is set to true if this function changed the
119  * logical value of *dst, otherwise it is left as is.
120  */
121 static inline void ethnl_update_bool32(u32 *dst, const struct nlattr *attr,
122 				       bool *mod)
123 {
124 	u8 val;
125 
126 	if (!attr)
127 		return;
128 	val = !!nla_get_u8(attr);
129 	if (!!*dst == val)
130 		return;
131 
132 	*dst = val;
133 	*mod = true;
134 }
135 
136 /**
137  * ethnl_update_binary() - update binary data from NLA_BINARY atribute
138  * @dst:  value to update
139  * @len:  destination buffer length
140  * @attr: netlink attribute with new value or null
141  * @mod:  pointer to bool for modification tracking
142  *
143  * Use the u8 value from NLA_U8 netlink attribute @attr to rewrite data block
144  * of length @len at @dst by attribute payload; do nothing if @attr is null.
145  * Bool pointed to by @mod is set to true if this function changed the logical
146  * value of *dst, otherwise it is left as is.
147  */
148 static inline void ethnl_update_binary(void *dst, unsigned int len,
149 				       const struct nlattr *attr, bool *mod)
150 {
151 	if (!attr)
152 		return;
153 	if (nla_len(attr) < len)
154 		len = nla_len(attr);
155 	if (!memcmp(dst, nla_data(attr), len))
156 		return;
157 
158 	memcpy(dst, nla_data(attr), len);
159 	*mod = true;
160 }
161 
162 /**
163  * ethnl_update_bitfield32() - update u32 value from NLA_BITFIELD32 attribute
164  * @dst:  value to update
165  * @attr: netlink attribute with new value or null
166  * @mod:  pointer to bool for modification tracking
167  *
168  * Update bits in u32 value which are set in attribute's mask to values from
169  * attribute's value. Do nothing if @attr is null or the value wouldn't change;
170  * otherwise, set bool pointed to by @mod to true.
171  */
172 static inline void ethnl_update_bitfield32(u32 *dst, const struct nlattr *attr,
173 					   bool *mod)
174 {
175 	struct nla_bitfield32 change;
176 	u32 newval;
177 
178 	if (!attr)
179 		return;
180 	change = nla_get_bitfield32(attr);
181 	newval = (*dst & ~change.selector) | (change.value & change.selector);
182 	if (*dst == newval)
183 		return;
184 
185 	*dst = newval;
186 	*mod = true;
187 }
188 
189 /**
190  * ethnl_reply_header_size() - total size of reply header
191  *
192  * This is an upper estimate so that we do not need to hold RTNL lock longer
193  * than necessary (to prevent rename between size estimate and composing the
194  * message). Accounts only for device ifindex and name as those are the only
195  * attributes ethnl_fill_reply_header() puts into the reply header.
196  */
197 static inline unsigned int ethnl_reply_header_size(void)
198 {
199 	return nla_total_size(nla_total_size(sizeof(u32)) +
200 			      nla_total_size(IFNAMSIZ));
201 }
202 
203 /* GET request handling */
204 
205 /* Unified processing of GET requests uses two data structures: request info
206  * and reply data. Request info holds information parsed from client request
207  * and its stays constant through all request processing. Reply data holds data
208  * retrieved from ethtool_ops callbacks or other internal sources which is used
209  * to compose the reply. When processing a dump request, request info is filled
210  * only once (when the request message is parsed) but reply data is filled for
211  * each reply message.
212  *
213  * Both structures consist of part common for all request types (struct
214  * ethnl_req_info and struct ethnl_reply_data defined below) and optional
215  * parts specific for each request type. Common part always starts at offset 0.
216  */
217 
218 /**
219  * struct ethnl_req_info - base type of request information for GET requests
220  * @dev:   network device the request is for (may be null)
221  * @flags: request flags common for all request types
222  *
223  * This is a common base for request specific structures holding data from
224  * parsed userspace request. These always embed struct ethnl_req_info at
225  * zero offset.
226  */
227 struct ethnl_req_info {
228 	struct net_device	*dev;
229 	u32			flags;
230 };
231 
232 /**
233  * struct ethnl_reply_data - base type of reply data for GET requests
234  * @dev:       device for current reply message; in single shot requests it is
235  *             equal to &ethnl_req_info.dev; in dumps it's different for each
236  *             reply message
237  *
238  * This is a common base for request specific structures holding data for
239  * kernel reply message. These always embed struct ethnl_reply_data at zero
240  * offset.
241  */
242 struct ethnl_reply_data {
243 	struct net_device		*dev;
244 };
245 
246 static inline int ethnl_ops_begin(struct net_device *dev)
247 {
248 	if (dev && dev->ethtool_ops->begin)
249 		return dev->ethtool_ops->begin(dev);
250 	else
251 		return 0;
252 }
253 
254 static inline void ethnl_ops_complete(struct net_device *dev)
255 {
256 	if (dev && dev->ethtool_ops->complete)
257 		dev->ethtool_ops->complete(dev);
258 }
259 
260 /**
261  * struct ethnl_request_ops - unified handling of GET requests
262  * @request_cmd:      command id for request (GET)
263  * @reply_cmd:        command id for reply (GET_REPLY)
264  * @hdr_attr:         attribute type for request header
265  * @max_attr:         maximum (top level) attribute type
266  * @req_info_size:    size of request info
267  * @reply_data_size:  size of reply data
268  * @request_policy:   netlink policy for message contents
269  * @allow_nodev_do:   allow non-dump request with no device identification
270  * @parse_request:
271  *	Parse request except common header (struct ethnl_req_info). Common
272  *	header is already filled on entry, the rest up to @repdata_offset
273  *	is zero initialized. This callback should only modify type specific
274  *	request info by parsed attributes from request message.
275  * @prepare_data:
276  *	Retrieve and prepare data needed to compose a reply message. Calls to
277  *	ethtool_ops handlers are limited to this callback. Common reply data
278  *	(struct ethnl_reply_data) is filled on entry, type specific part after
279  *	it is zero initialized. This callback should only modify the type
280  *	specific part of reply data. Device identification from struct
281  *	ethnl_reply_data is to be used as for dump requests, it iterates
282  *	through network devices while dev member of struct ethnl_req_info
283  *	points to the device from client request.
284  * @reply_size:
285  *	Estimate reply message size. Returned value must be sufficient for
286  *	message payload without common reply header. The callback may returned
287  *	estimate higher than actual message size if exact calculation would
288  *	not be worth the saved memory space.
289  * @fill_reply:
290  *	Fill reply message payload (except for common header) from reply data.
291  *	The callback must not generate more payload than previously called
292  *	->reply_size() estimated.
293  * @cleanup_data:
294  *	Optional cleanup called when reply data is no longer needed. Can be
295  *	used e.g. to free any additional data structures outside the main
296  *	structure which were allocated by ->prepare_data(). When processing
297  *	dump requests, ->cleanup() is called for each message.
298  *
299  * Description of variable parts of GET request handling when using the
300  * unified infrastructure. When used, a pointer to an instance of this
301  * structure is to be added to &ethnl_default_requests array and generic
302  * handlers ethnl_default_doit(), ethnl_default_dumpit(),
303  * ethnl_default_start() and ethnl_default_done() used in @ethtool_genl_ops;
304  * ethnl_default_notify() can be used in @ethnl_notify_handlers to send
305  * notifications of the corresponding type.
306  */
307 struct ethnl_request_ops {
308 	u8			request_cmd;
309 	u8			reply_cmd;
310 	u16			hdr_attr;
311 	unsigned int		max_attr;
312 	unsigned int		req_info_size;
313 	unsigned int		reply_data_size;
314 	const struct nla_policy *request_policy;
315 	bool			allow_nodev_do;
316 
317 	int (*parse_request)(struct ethnl_req_info *req_info,
318 			     struct nlattr **tb,
319 			     struct netlink_ext_ack *extack);
320 	int (*prepare_data)(const struct ethnl_req_info *req_info,
321 			    struct ethnl_reply_data *reply_data,
322 			    struct genl_info *info);
323 	int (*reply_size)(const struct ethnl_req_info *req_info,
324 			  const struct ethnl_reply_data *reply_data);
325 	int (*fill_reply)(struct sk_buff *skb,
326 			  const struct ethnl_req_info *req_info,
327 			  const struct ethnl_reply_data *reply_data);
328 	void (*cleanup_data)(struct ethnl_reply_data *reply_data);
329 };
330 
331 /* request handlers */
332 
333 extern const struct ethnl_request_ops ethnl_strset_request_ops;
334 extern const struct ethnl_request_ops ethnl_linkinfo_request_ops;
335 extern const struct ethnl_request_ops ethnl_linkmodes_request_ops;
336 extern const struct ethnl_request_ops ethnl_linkstate_request_ops;
337 extern const struct ethnl_request_ops ethnl_debug_request_ops;
338 extern const struct ethnl_request_ops ethnl_wol_request_ops;
339 
340 int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info);
341 int ethnl_set_linkmodes(struct sk_buff *skb, struct genl_info *info);
342 int ethnl_set_debug(struct sk_buff *skb, struct genl_info *info);
343 int ethnl_set_wol(struct sk_buff *skb, struct genl_info *info);
344 
345 #endif /* _NET_ETHTOOL_NETLINK_H */
346