1 /* 2 * netlink/attr.h Netlink Attributes 3 * 4 * This library is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Lesser General Public 6 * License as published by the Free Software Foundation version 2.1 7 * of the License. 8 * 9 * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch> 10 */ 11 12 #ifndef NETLINK_ATTR_H_ 13 #define NETLINK_ATTR_H_ 14 15 #include <netlink/netlink.h> 16 #include <netlink/object.h> 17 #include <netlink/addr.h> 18 #include <netlink/data.h> 19 20 #ifdef __cplusplus 21 extern "C" { 22 #endif 23 24 struct nl_msg; 25 26 /** 27 * @name Basic Attribute Data Types 28 * @{ 29 */ 30 31 /** 32 * @ingroup attr 33 * Basic attribute data types 34 * 35 * See \ref attr_datatypes for more details. 36 */ 37 enum { 38 NLA_UNSPEC, /**< Unspecified type, binary data chunk */ 39 NLA_U8, /**< 8 bit integer */ 40 NLA_U16, /**< 16 bit integer */ 41 NLA_U32, /**< 32 bit integer */ 42 NLA_U64, /**< 64 bit integer */ 43 NLA_STRING, /**< NUL terminated character string */ 44 NLA_FLAG, /**< Flag */ 45 NLA_MSECS, /**< Micro seconds (64bit) */ 46 NLA_NESTED, /**< Nested attributes */ 47 __NLA_TYPE_MAX, 48 }; 49 50 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1) 51 52 /** @} */ 53 54 /** 55 * @ingroup attr 56 * Attribute validation policy. 57 * 58 * See \ref attr_datatypes for more details. 59 */ 60 struct nla_policy { 61 /** Type of attribute or NLA_UNSPEC */ 62 uint16_t type; 63 64 /** Minimal length of payload required */ 65 uint16_t minlen; 66 67 /** Maximal length of payload allowed */ 68 uint16_t maxlen; 69 }; 70 71 /* Size calculations */ 72 extern int nla_attr_size(int payload); 73 extern int nla_total_size(int payload); 74 extern int nla_padlen(int payload); 75 76 /* Attribute parsing */ 77 extern int nla_type(const struct nlattr *); 78 extern void * nla_data(const struct nlattr *); 79 extern int nla_len(const struct nlattr *); 80 extern int nla_ok(const struct nlattr *, int); 81 extern struct nlattr * nla_next(const struct nlattr *, int *); 82 extern int nla_parse(struct nlattr **, int, struct nlattr *, 83 int, struct nla_policy *); 84 extern int nla_validate(struct nlattr *, int, int, 85 struct nla_policy *); 86 extern struct nlattr * nla_find(struct nlattr *, int, int); 87 88 /* Helper Functions */ 89 extern int nla_memcpy(void *, struct nlattr *, int); 90 extern size_t nla_strlcpy(char *, const struct nlattr *, size_t); 91 extern int nla_memcmp(const struct nlattr *, const void *, size_t); 92 extern int nla_strcmp(const struct nlattr *, const char *); 93 94 /* Unspecific attribute */ 95 extern struct nlattr * nla_reserve(struct nl_msg *, int, int); 96 extern int nla_put(struct nl_msg *, int, int, const void *); 97 extern int nla_put_data(struct nl_msg *, int, struct nl_data *); 98 extern int nla_put_addr(struct nl_msg *, int, struct nl_addr *); 99 100 /* Integer attribute */ 101 extern uint8_t nla_get_u8(struct nlattr *); 102 extern int nla_put_u8(struct nl_msg *, int, uint8_t); 103 extern uint16_t nla_get_u16(struct nlattr *); 104 extern int nla_put_u16(struct nl_msg *, int, uint16_t); 105 extern uint32_t nla_get_u32(struct nlattr *); 106 extern int nla_put_u32(struct nl_msg *, int, uint32_t); 107 extern uint64_t nla_get_u64(struct nlattr *); 108 extern int nla_put_u64(struct nl_msg *, int, uint64_t); 109 110 /* String attribute */ 111 extern char * nla_get_string(struct nlattr *); 112 extern char * nla_strdup(struct nlattr *); 113 extern int nla_put_string(struct nl_msg *, int, const char *); 114 115 /* Flag attribute */ 116 extern int nla_get_flag(struct nlattr *); 117 extern int nla_put_flag(struct nl_msg *, int); 118 119 /* Msec attribute */ 120 extern unsigned long nla_get_msecs(struct nlattr *); 121 extern int nla_put_msecs(struct nl_msg *, int, unsigned long); 122 123 /* Attribute nesting */ 124 extern int nla_put_nested(struct nl_msg *, int, struct nl_msg *); 125 extern struct nlattr * nla_nest_start(struct nl_msg *, int); 126 extern int nla_nest_end(struct nl_msg *, struct nlattr *); 127 extern int nla_parse_nested(struct nlattr **, int, struct nlattr *, 128 struct nla_policy *); 129 130 /** 131 * @name Attribute Construction (Exception Based) 132 * @{ 133 */ 134 135 /** 136 * @ingroup attr 137 * Add unspecific attribute to netlink message. 138 * @arg msg Netlink message. 139 * @arg attrtype Attribute type. 140 * @arg attrlen Length of attribute payload. 141 * @arg data Head of attribute payload. 142 */ 143 #define NLA_PUT(msg, attrtype, attrlen, data) \ 144 do { \ 145 if (nla_put(msg, attrtype, attrlen, data) < 0) \ 146 goto nla_put_failure; \ 147 } while(0) 148 149 /** 150 * @ingroup attr 151 * Add atomic type attribute to netlink message. 152 * @arg msg Netlink message. 153 * @arg type Atomic type. 154 * @arg attrtype Attribute type. 155 * @arg value Head of attribute payload. 156 */ 157 #define NLA_PUT_TYPE(msg, type, attrtype, value) \ 158 do { \ 159 type __tmp = value; \ 160 NLA_PUT(msg, attrtype, sizeof(type), &__tmp); \ 161 } while(0) 162 163 /** 164 * Add 8 bit integer attribute to netlink message. 165 * @arg msg Netlink message. 166 * @arg attrtype Attribute type. 167 * @arg value Numeric value. 168 */ 169 #define NLA_PUT_U8(msg, attrtype, value) \ 170 NLA_PUT_TYPE(msg, uint8_t, attrtype, value) 171 172 /** 173 * Add 16 bit integer attribute to netlink message. 174 * @arg msg Netlink message. 175 * @arg attrtype Attribute type. 176 * @arg value Numeric value. 177 */ 178 #define NLA_PUT_U16(msg, attrtype, value) \ 179 NLA_PUT_TYPE(msg, uint16_t, attrtype, value) 180 181 /** 182 * Add 32 bit integer attribute to netlink message. 183 * @arg msg Netlink message. 184 * @arg attrtype Attribute type. 185 * @arg value Numeric value. 186 */ 187 #define NLA_PUT_U32(msg, attrtype, value) \ 188 NLA_PUT_TYPE(msg, uint32_t, attrtype, value) 189 190 /** 191 * Add 64 bit integer attribute to netlink message. 192 * @arg msg Netlink message. 193 * @arg attrtype Attribute type. 194 * @arg value Numeric value. 195 */ 196 #define NLA_PUT_U64(msg, attrtype, value) \ 197 NLA_PUT_TYPE(msg, uint64_t, attrtype, value) 198 199 /** 200 * Add string attribute to netlink message. 201 * @arg msg Netlink message. 202 * @arg attrtype Attribute type. 203 * @arg value NUL terminated character string. 204 */ 205 #define NLA_PUT_STRING(msg, attrtype, value) \ 206 NLA_PUT(msg, attrtype, strlen(value) + 1, value) 207 208 /** 209 * Add flag attribute to netlink message. 210 * @arg msg Netlink message. 211 * @arg attrtype Attribute type. 212 */ 213 #define NLA_PUT_FLAG(msg, attrtype) \ 214 NLA_PUT(msg, attrtype, 0, NULL) 215 216 /** 217 * Add msecs attribute to netlink message. 218 * @arg msg Netlink message. 219 * @arg attrtype Attribute type. 220 * @arg msecs Numeric value in micro seconds. 221 */ 222 #define NLA_PUT_MSECS(msg, attrtype, msecs) \ 223 NLA_PUT_U64(msg, attrtype, msecs) 224 225 /** 226 * Add address attribute to netlink message. 227 * @arg msg Netlink message. 228 * @arg attrtype Attribute type. 229 * @arg addr Abstract address object. 230 */ 231 #define NLA_PUT_ADDR(msg, attrtype, addr) \ 232 NLA_PUT(msg, attrtype, nl_addr_get_len(addr), \ 233 nl_addr_get_binary_addr(addr)) 234 235 /** 236 * Add abstract data attribute to netlink message. 237 * @arg msg Netlink message. 238 * @arg attrtype Attribute type. 239 * @arg data Abstract data object. 240 */ 241 #define NLA_PUT_DATA(msg, attrtype, data) \ 242 NLA_PUT(msg, attrtype, nl_data_get_size(data), \ 243 nl_data_get(data)) 244 245 /** @} */ 246 247 /** 248 * @name Iterators 249 * @{ 250 */ 251 252 /** 253 * @ingroup attr 254 * Iterate over a stream of attributes 255 * @arg pos loop counter, set to current attribute 256 * @arg head head of attribute stream 257 * @arg len length of attribute stream 258 * @arg rem initialized to len, holds bytes currently remaining in stream 259 */ 260 #define nla_for_each_attr(pos, head, len, rem) \ 261 for (pos = head, rem = len; \ 262 nla_ok(pos, rem); \ 263 pos = nla_next(pos, &(rem))) 264 265 /** 266 * @ingroup attr 267 * Iterate over a stream of nested attributes 268 * @arg pos loop counter, set to current attribute 269 * @arg nla attribute containing the nested attributes 270 * @arg rem initialized to len, holds bytes currently remaining in stream 271 */ 272 #define nla_for_each_nested(pos, nla, rem) \ 273 for (pos = nla_data(nla), rem = nla_len(nla); \ 274 nla_ok(pos, rem); \ 275 pos = nla_next(pos, &(rem))) 276 277 /** @} */ 278 279 #ifdef __cplusplus 280 } 281 #endif 282 283 #endif 284