net/ethtool/netlink.h

   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  */
 305 struct ethnl_request_ops {
 306         u8                      request_cmd;
 307         u8                      reply_cmd;
 308         u16                     hdr_attr;
 309         unsigned int            max_attr;
 310         unsigned int            req_info_size;
 311         unsigned int            reply_data_size;
 312         const struct nla_policy *request_policy;
 313         bool                    allow_nodev_do;
 314
 315         int (*parse_request)(struct ethnl_req_info *req_info,
 316                              struct nlattr **tb,
 317                              struct netlink_ext_ack *extack);
 318         int (*prepare_data)(const struct ethnl_req_info *req_info,
 319                             struct ethnl_reply_data *reply_data,
 320                             struct genl_info *info);
 321         int (*reply_size)(const struct ethnl_req_info *req_info,
 322                           const struct ethnl_reply_data *reply_data);
 323         int (*fill_reply)(struct sk_buff *skb,
 324                           const struct ethnl_req_info *req_info,
 325                           const struct ethnl_reply_data *reply_data);
 326         void (*cleanup_data)(struct ethnl_reply_data *reply_data);
 327 };
 328
 329 /* request handlers */
 330
 331 extern const struct ethnl_request_ops ethnl_strset_request_ops;
 332 extern const struct ethnl_request_ops ethnl_linkinfo_request_ops;
 333
 334 int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info);
 335
 336 #endif /* _NET_ETHTOOL_NETLINK_H */