1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2021 Ng Peng Nam Sean 5 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef _NETLINK_NETLINK_MESSAGE_WRITER_H_ 30 #define _NETLINK_NETLINK_MESSAGE_WRITER_H_ 31 32 #ifdef _KERNEL 33 34 #include <netinet/in.h> 35 36 /* 37 * It is not meant to be included directly 38 */ 39 40 struct mbuf; 41 struct nl_writer; 42 typedef bool nl_writer_cb(struct nl_writer *nw, void *buf, int buflen, int cnt); 43 44 struct nl_writer { 45 int alloc_len; /* allocated buffer length */ 46 int offset; /* offset from the start of the buffer */ 47 struct nlmsghdr *hdr; /* Pointer to the currently-filled msg */ 48 char *data; /* pointer to the contiguous storage */ 49 void *_storage; /* Underlying storage pointer */ 50 nl_writer_cb *cb; /* Callback to flush data */ 51 union { 52 void *ptr; 53 struct { 54 uint16_t proto; 55 uint16_t id; 56 } group; 57 } arg; 58 int num_messages; /* Number of messages in the buffer */ 59 int malloc_flag; /* M_WAITOK or M_NOWAIT */ 60 uint8_t writer_type; /* NS_WRITER_TYPE_* */ 61 uint8_t writer_target; /* NS_WRITER_TARGET_* */ 62 bool ignore_limit; /* If true, ignores RCVBUF limit */ 63 bool enomem; /* True if ENOMEM occured */ 64 bool suppress_ack; /* If true, don't send NLMSG_ERR */ 65 }; 66 #define NS_WRITER_TARGET_SOCKET 0 67 #define NS_WRITER_TARGET_GROUP 1 68 #define NS_WRITER_TARGET_CHAIN 2 69 70 #define NS_WRITER_TYPE_MBUF 0 71 #define NS_WRITER_TYPE_BUF 1 72 #define NS_WRITER_TYPE_LBUF 2 73 #define NS_WRITER_TYPE_MBUFC 3 74 #define NS_WRITER_TYPE_STUB 4 75 76 77 #define NLMSG_SMALL 128 78 #define NLMSG_LARGE 2048 79 80 /* Message and attribute writing */ 81 82 struct nlpcb; 83 84 #if defined(NETLINK) || defined(NETLINK_MODULE) 85 /* Provide optimized calls to the functions inside the same linking unit */ 86 87 bool _nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp); 88 bool _nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id); 89 bool _nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm); 90 bool _nlmsg_flush(struct nl_writer *nw); 91 void _nlmsg_ignore_limit(struct nl_writer *nw); 92 93 bool _nlmsg_refill_buffer(struct nl_writer *nw, int required_size); 94 bool _nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type, 95 uint16_t flags, uint32_t len); 96 bool _nlmsg_end(struct nl_writer *nw); 97 void _nlmsg_abort(struct nl_writer *nw); 98 99 bool _nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr); 100 101 102 static inline bool 103 nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp) 104 { 105 return (_nlmsg_get_unicast_writer(nw, expected_size, nlp)); 106 } 107 108 static inline bool 109 nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id) 110 { 111 return (_nlmsg_get_group_writer(nw, expected_size, proto, group_id)); 112 } 113 114 static inline bool 115 nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm) 116 { 117 return (_nlmsg_get_chain_writer(nw, expected_size, pm)); 118 } 119 120 static inline bool 121 nlmsg_flush(struct nl_writer *nw) 122 { 123 return (_nlmsg_flush(nw)); 124 } 125 126 static inline void 127 nlmsg_ignore_limit(struct nl_writer *nw) 128 { 129 _nlmsg_ignore_limit(nw); 130 } 131 132 static inline bool 133 nlmsg_refill_buffer(struct nl_writer *nw, int required_size) 134 { 135 return (_nlmsg_refill_buffer(nw, required_size)); 136 } 137 138 static inline bool 139 nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type, 140 uint16_t flags, uint32_t len) 141 { 142 return (_nlmsg_add(nw, portid, seq, type, flags, len)); 143 } 144 145 static inline bool 146 nlmsg_end(struct nl_writer *nw) 147 { 148 return (_nlmsg_end(nw)); 149 } 150 151 static inline void 152 nlmsg_abort(struct nl_writer *nw) 153 { 154 return (_nlmsg_abort(nw)); 155 } 156 157 static inline bool 158 nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr) 159 { 160 return (_nlmsg_end_dump(nw, error, hdr)); 161 } 162 163 #else 164 /* Provide access to the functions via netlink_glue.c */ 165 166 bool nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp); 167 bool nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id); 168 bool nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm); 169 bool nlmsg_flush(struct nl_writer *nw); 170 void nlmsg_ignore_limit(struct nl_writer *nw); 171 172 bool nlmsg_refill_buffer(struct nl_writer *nw, int required_size); 173 bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type, 174 uint16_t flags, uint32_t len); 175 bool nlmsg_end(struct nl_writer *nw); 176 void nlmsg_abort(struct nl_writer *nw); 177 178 bool nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr); 179 180 #endif /* defined(NETLINK) || defined(NETLINK_MODULE) */ 181 182 static inline bool 183 nlmsg_reply(struct nl_writer *nw, const struct nlmsghdr *hdr, int payload_len) 184 { 185 return (nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, hdr->nlmsg_type, 186 hdr->nlmsg_flags, payload_len)); 187 } 188 189 #define nlmsg_data(_hdr) ((void *)((_hdr) + 1)) 190 191 /* 192 * KPI similar to mtodo(): 193 * current (uncompleted) header is guaranteed to be contiguous, 194 * but can be reallocated, thus pointers may need to be readjusted. 195 */ 196 static inline int 197 nlattr_save_offset(const struct nl_writer *nw) 198 { 199 return (nw->offset - ((char *)nw->hdr - nw->data)); 200 } 201 202 static inline void * 203 _nlattr_restore_offset(const struct nl_writer *nw, int off) 204 { 205 return ((void *)((char *)nw->hdr + off)); 206 } 207 #define nlattr_restore_offset(_ns, _off, _t) ((_t *)_nlattr_restore_offset(_ns, _off)) 208 209 static inline void 210 nlattr_set_len(const struct nl_writer *nw, int off) 211 { 212 struct nlattr *nla = nlattr_restore_offset(nw, off, struct nlattr); 213 nla->nla_len = nlattr_save_offset(nw) - off; 214 } 215 216 static inline void * 217 nlmsg_reserve_data_raw(struct nl_writer *nw, size_t sz) 218 { 219 sz = NETLINK_ALIGN(sz); 220 221 if (__predict_false(nw->offset + sz > nw->alloc_len)) { 222 if (!nlmsg_refill_buffer(nw, sz)) 223 return (NULL); 224 } 225 226 void *data_ptr = &nw->data[nw->offset]; 227 nw->offset += sz; 228 229 return (data_ptr); 230 } 231 #define nlmsg_reserve_object(_ns, _t) ((_t *)nlmsg_reserve_data_raw(_ns, sizeof(_t))) 232 #define nlmsg_reserve_data(_ns, _sz, _t) ((_t *)nlmsg_reserve_data_raw(_ns, _sz)) 233 234 static inline int 235 nlattr_add_nested(struct nl_writer *nw, uint16_t nla_type) 236 { 237 int off = nlattr_save_offset(nw); 238 struct nlattr *nla = nlmsg_reserve_data(nw, sizeof(struct nlattr), struct nlattr); 239 if (__predict_false(nla == NULL)) 240 return (0); 241 nla->nla_type = nla_type; 242 return (off); 243 } 244 245 static inline void * 246 _nlmsg_reserve_attr(struct nl_writer *nw, uint16_t nla_type, uint16_t sz) 247 { 248 sz += sizeof(struct nlattr); 249 250 struct nlattr *nla = nlmsg_reserve_data(nw, sz, struct nlattr); 251 if (__predict_false(nla == NULL)) 252 return (NULL); 253 nla->nla_type = nla_type; 254 nla->nla_len = sz; 255 256 return ((void *)(nla + 1)); 257 } 258 #define nlmsg_reserve_attr(_ns, _at, _t) ((_t *)_nlmsg_reserve_attr(_ns, _at, NLA_ALIGN(sizeof(_t)))) 259 260 static inline bool 261 nlattr_add(struct nl_writer *nw, int attr_type, int attr_len, const void *data) 262 { 263 int required_len = NLA_ALIGN(attr_len + sizeof(struct nlattr)); 264 265 if (__predict_false(nw->offset + required_len > nw->alloc_len)) { 266 if (!nlmsg_refill_buffer(nw, required_len)) 267 return (false); 268 } 269 270 struct nlattr *nla = (struct nlattr *)(&nw->data[nw->offset]); 271 272 nla->nla_len = attr_len + sizeof(struct nlattr); 273 nla->nla_type = attr_type; 274 if (attr_len > 0) { 275 if ((attr_len % 4) != 0) { 276 /* clear padding bytes */ 277 bzero((char *)nla + required_len - 4, 4); 278 } 279 memcpy((nla + 1), data, attr_len); 280 } 281 nw->offset += required_len; 282 return (true); 283 } 284 285 static inline bool 286 nlattr_add_raw(struct nl_writer *nw, const struct nlattr *nla_src) 287 { 288 int attr_len = nla_src->nla_len - sizeof(struct nlattr); 289 290 MPASS(attr_len >= 0); 291 292 return (nlattr_add(nw, nla_src->nla_type, attr_len, (const void *)(nla_src + 1))); 293 } 294 295 static inline bool 296 nlattr_add_u8(struct nl_writer *nw, int attrtype, uint8_t value) 297 { 298 return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value)); 299 } 300 301 static inline bool 302 nlattr_add_u16(struct nl_writer *nw, int attrtype, uint16_t value) 303 { 304 return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value)); 305 } 306 307 static inline bool 308 nlattr_add_u32(struct nl_writer *nw, int attrtype, uint32_t value) 309 { 310 return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value)); 311 } 312 313 static inline bool 314 nlattr_add_u64(struct nl_writer *nw, int attrtype, uint64_t value) 315 { 316 return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value)); 317 } 318 319 static inline bool 320 nlattr_add_s8(struct nl_writer *nw, int attrtype, int8_t value) 321 { 322 return (nlattr_add(nw, attrtype, sizeof(int8_t), &value)); 323 } 324 325 static inline bool 326 nlattr_add_s16(struct nl_writer *nw, int attrtype, int16_t value) 327 { 328 return (nlattr_add(nw, attrtype, sizeof(int16_t), &value)); 329 } 330 331 static inline bool 332 nlattr_add_s32(struct nl_writer *nw, int attrtype, int32_t value) 333 { 334 return (nlattr_add(nw, attrtype, sizeof(int32_t), &value)); 335 } 336 337 static inline bool 338 nlattr_add_s64(struct nl_writer *nw, int attrtype, int64_t value) 339 { 340 return (nlattr_add(nw, attrtype, sizeof(int64_t), &value)); 341 } 342 343 static inline bool 344 nlattr_add_flag(struct nl_writer *nw, int attrtype) 345 { 346 return (nlattr_add(nw, attrtype, 0, NULL)); 347 } 348 349 static inline bool 350 nlattr_add_string(struct nl_writer *nw, int attrtype, const char *str) 351 { 352 return (nlattr_add(nw, attrtype, strlen(str) + 1, str)); 353 } 354 355 static inline bool 356 nlattr_add_in_addr(struct nl_writer *nw, int attrtype, const struct in_addr *in) 357 { 358 return (nlattr_add(nw, attrtype, sizeof(*in), in)); 359 } 360 361 static inline bool 362 nlattr_add_in6_addr(struct nl_writer *nw, int attrtype, const struct in6_addr *in6) 363 { 364 return (nlattr_add(nw, attrtype, sizeof(*in6), in6)); 365 } 366 #endif 367 #endif 368