1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 #ifndef _NETLINK_NETLINK_SNL_H_ 28 #define _NETLINK_NETLINK_SNL_H_ 29 30 /* 31 * Simple Netlink Library 32 */ 33 34 #include <assert.h> 35 #include <errno.h> 36 #include <stddef.h> 37 #include <stdbool.h> 38 #include <stdint.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <unistd.h> 42 43 #include <sys/types.h> 44 #include <sys/socket.h> 45 #include <netlink/netlink.h> 46 47 #define _roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) 48 49 #define NETLINK_ALIGN_SIZE sizeof(uint32_t) 50 #define NETLINK_ALIGN(_len) _roundup2(_len, NETLINK_ALIGN_SIZE) 51 52 #define NLA_ALIGN_SIZE sizeof(uint32_t) 53 #define NLA_HDRLEN ((int)sizeof(struct nlattr)) 54 #define NLA_DATA_LEN(_nla) ((int)((_nla)->nla_len - NLA_HDRLEN)) 55 #define NLA_DATA(_nla) NL_ITEM_DATA(_nla, NLA_HDRLEN) 56 #define NLA_DATA_CONST(_nla) NL_ITEM_DATA_CONST(_nla, NLA_HDRLEN) 57 58 #define NLA_TYPE(_nla) ((_nla)->nla_type & 0x3FFF) 59 60 #define NLA_NEXT(_attr) (struct nlattr *)(void *)((char *)_attr + NLA_ALIGN(_attr->nla_len)) 61 62 #define _NLA_END(_start, _len) ((char *)(_start) + (_len)) 63 #define NLA_FOREACH(_attr, _start, _len) \ 64 for (_attr = (_start); \ 65 ((char *)_attr < _NLA_END(_start, _len)) && \ 66 ((char *)NLA_NEXT(_attr) <= _NLA_END(_start, _len)); \ 67 _attr = NLA_NEXT(_attr)) 68 69 #define NL_ARRAY_LEN(_a) (sizeof(_a) / sizeof((_a)[0])) 70 71 struct linear_buffer { 72 char *base; /* Base allocated memory pointer */ 73 uint32_t offset; /* Currently used offset */ 74 uint32_t size; /* Total buffer size */ 75 struct linear_buffer *next; /* Buffer chaining */ 76 }; 77 78 static inline struct linear_buffer * 79 lb_init(uint32_t size) 80 { 81 struct linear_buffer *lb = calloc(1, size); 82 83 if (lb != NULL) { 84 lb->base = (char *)(lb + 1); 85 lb->size = size - sizeof(*lb); 86 } 87 88 return (lb); 89 } 90 91 static inline void 92 lb_free(struct linear_buffer *lb) 93 { 94 free(lb); 95 } 96 97 static inline char * 98 lb_allocz(struct linear_buffer *lb, int len) 99 { 100 len = roundup2(len, sizeof(uint64_t)); 101 if (lb->offset + len > lb->size) 102 return (NULL); 103 void *data = (void *)(lb->base + lb->offset); 104 lb->offset += len; 105 return (data); 106 } 107 108 static inline void 109 lb_clear(struct linear_buffer *lb) 110 { 111 memset(lb->base, 0, lb->offset); 112 lb->offset = 0; 113 } 114 115 struct snl_state { 116 int fd; 117 char *buf; 118 size_t off; 119 size_t bufsize; 120 size_t datalen; 121 uint32_t seq; 122 bool init_done; 123 struct linear_buffer *lb; 124 }; 125 #define SCRATCH_BUFFER_SIZE 1024 126 #define SNL_WRITER_BUFFER_SIZE 256 127 128 typedef void snl_parse_field_f(struct snl_state *ss, void *hdr, void *target); 129 struct snl_field_parser { 130 uint16_t off_in; 131 uint16_t off_out; 132 snl_parse_field_f *cb; 133 }; 134 135 typedef bool snl_parse_attr_f(struct snl_state *ss, struct nlattr *attr, 136 const void *arg, void *target); 137 struct snl_attr_parser { 138 uint16_t type; /* Attribute type */ 139 uint16_t off; /* field offset in the target structure */ 140 snl_parse_attr_f *cb; /* parser function to call */ 141 const void *arg; /* Optional argument parser */ 142 }; 143 144 struct snl_hdr_parser { 145 int hdr_off; /* aligned header size */ 146 int fp_size; 147 int np_size; 148 const struct snl_field_parser *fp; /* array of header field parsers */ 149 const struct snl_attr_parser *np; /* array of attribute parsers */ 150 }; 151 152 #define SNL_DECLARE_PARSER(_name, _t, _fp, _np) \ 153 static const struct snl_hdr_parser _name = { \ 154 .hdr_off = sizeof(_t), \ 155 .fp = &((_fp)[0]), \ 156 .np = &((_np)[0]), \ 157 .fp_size = NL_ARRAY_LEN(_fp), \ 158 .np_size = NL_ARRAY_LEN(_np), \ 159 } 160 161 #define SNL_DECLARE_ATTR_PARSER(_name, _np) \ 162 static const struct snl_hdr_parser _name = { \ 163 .np = &((_np)[0]), \ 164 .np_size = NL_ARRAY_LEN(_np), \ 165 } 166 167 168 static inline void * 169 snl_allocz(struct snl_state *ss, int len) 170 { 171 void *data = lb_allocz(ss->lb, len); 172 173 if (data == NULL) { 174 uint32_t size = ss->lb->size * 2; 175 176 while (size < len + sizeof(struct linear_buffer)) 177 size *= 2; 178 179 struct linear_buffer *lb = lb_init(size); 180 181 if (lb != NULL) { 182 lb->next = ss->lb; 183 ss->lb = lb; 184 data = lb_allocz(ss->lb, len); 185 } 186 } 187 188 return (data); 189 } 190 191 static inline void 192 snl_clear_lb(struct snl_state *ss) 193 { 194 struct linear_buffer *lb = ss->lb; 195 196 lb_clear(lb); 197 lb = lb->next; 198 ss->lb->next = NULL; 199 /* Remove all linear bufs except the largest one */ 200 while (lb != NULL) { 201 struct linear_buffer *lb_next = lb->next; 202 lb_free(lb); 203 lb = lb_next; 204 } 205 } 206 207 static void 208 snl_free(struct snl_state *ss) 209 { 210 if (ss->init_done) { 211 close(ss->fd); 212 if (ss->buf != NULL) 213 free(ss->buf); 214 if (ss->lb != NULL) { 215 snl_clear_lb(ss); 216 lb_free(ss->lb); 217 } 218 } 219 } 220 221 static inline bool 222 snl_init(struct snl_state *ss, int netlink_family) 223 { 224 memset(ss, 0, sizeof(*ss)); 225 226 ss->fd = socket(AF_NETLINK, SOCK_RAW, netlink_family); 227 if (ss->fd == -1) 228 return (false); 229 ss->init_done = true; 230 231 int rcvbuf; 232 socklen_t optlen = sizeof(rcvbuf); 233 if (getsockopt(ss->fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &optlen) == -1) { 234 snl_free(ss); 235 return (false); 236 } 237 238 ss->bufsize = rcvbuf; 239 ss->buf = malloc(ss->bufsize); 240 if (ss->buf == NULL) { 241 snl_free(ss); 242 return (false); 243 } 244 245 ss->lb = lb_init(SCRATCH_BUFFER_SIZE); 246 if (ss->lb == NULL) { 247 snl_free(ss); 248 return (false); 249 } 250 251 return (true); 252 } 253 254 static inline bool 255 snl_send(struct snl_state *ss, void *data, int sz) 256 { 257 return (send(ss->fd, data, sz, 0) == sz); 258 } 259 260 static inline bool 261 snl_send_message(struct snl_state *ss, struct nlmsghdr *hdr) 262 { 263 ssize_t sz = NLMSG_ALIGN(hdr->nlmsg_len); 264 265 return (send(ss->fd, hdr, sz, 0) == sz); 266 } 267 268 static inline uint32_t 269 snl_get_seq(struct snl_state *ss) 270 { 271 return (++ss->seq); 272 } 273 274 static inline struct nlmsghdr * 275 snl_read_message(struct snl_state *ss) 276 { 277 if (ss->off == ss->datalen) { 278 struct sockaddr_nl nladdr; 279 struct iovec iov = { 280 .iov_base = ss->buf, 281 .iov_len = ss->bufsize, 282 }; 283 struct msghdr msg = { 284 .msg_name = &nladdr, 285 .msg_namelen = sizeof(nladdr), 286 .msg_iov = &iov, 287 .msg_iovlen = 1, 288 }; 289 ss->off = 0; 290 ss->datalen = 0; 291 for (;;) { 292 ssize_t datalen = recvmsg(ss->fd, &msg, 0); 293 if (datalen > 0) { 294 ss->datalen = datalen; 295 break; 296 } else if (errno != EINTR) 297 return (NULL); 298 } 299 } 300 struct nlmsghdr *hdr = (struct nlmsghdr *)(void *)&ss->buf[ss->off]; 301 ss->off += NLMSG_ALIGN(hdr->nlmsg_len); 302 return (hdr); 303 } 304 305 static inline struct nlmsghdr * 306 snl_read_reply(struct snl_state *ss, uint32_t nlmsg_seq) 307 { 308 struct nlmsghdr *hdr; 309 310 while ((hdr = snl_read_message(ss)) != NULL) { 311 if (hdr->nlmsg_seq == nlmsg_seq) 312 return (hdr); 313 } 314 315 return (NULL); 316 } 317 318 /* 319 * Checks that attributes are sorted by attribute type. 320 */ 321 static inline void 322 snl_verify_parsers(const struct snl_hdr_parser **parser, int count) 323 { 324 for (int i = 0; i < count; i++) { 325 const struct snl_hdr_parser *p = parser[i]; 326 int attr_type = 0; 327 for (int j = 0; j < p->np_size; j++) { 328 assert(p->np[j].type > attr_type); 329 attr_type = p->np[j].type; 330 } 331 } 332 } 333 #define SNL_VERIFY_PARSERS(_p) snl_verify_parsers((_p), NL_ARRAY_LEN(_p)) 334 335 static const struct snl_attr_parser * 336 find_parser(const struct snl_attr_parser *ps, int pslen, int key) 337 { 338 int left_i = 0, right_i = pslen - 1; 339 340 if (key < ps[0].type || key > ps[pslen - 1].type) 341 return (NULL); 342 343 while (left_i + 1 < right_i) { 344 int mid_i = (left_i + right_i) / 2; 345 if (key < ps[mid_i].type) 346 right_i = mid_i; 347 else if (key > ps[mid_i].type) 348 left_i = mid_i + 1; 349 else 350 return (&ps[mid_i]); 351 } 352 if (ps[left_i].type == key) 353 return (&ps[left_i]); 354 else if (ps[right_i].type == key) 355 return (&ps[right_i]); 356 return (NULL); 357 } 358 359 static inline bool 360 snl_parse_attrs_raw(struct snl_state *ss, struct nlattr *nla_head, int len, 361 const struct snl_attr_parser *ps, int pslen, void *target) 362 { 363 struct nlattr *nla; 364 365 NLA_FOREACH(nla, nla_head, len) { 366 if (nla->nla_len < sizeof(struct nlattr)) 367 return (false); 368 int nla_type = nla->nla_type & NLA_TYPE_MASK; 369 const struct snl_attr_parser *s = find_parser(ps, pslen, nla_type); 370 if (s != NULL) { 371 void *ptr = (void *)((char *)target + s->off); 372 if (!s->cb(ss, nla, s->arg, ptr)) 373 return (false); 374 } 375 } 376 return (true); 377 } 378 379 static inline bool 380 snl_parse_attrs(struct snl_state *ss, struct nlmsghdr *hdr, int hdrlen, 381 const struct snl_attr_parser *ps, int pslen, void *target) 382 { 383 int off = NLMSG_HDRLEN + NETLINK_ALIGN(hdrlen); 384 int len = hdr->nlmsg_len - off; 385 struct nlattr *nla_head = (struct nlattr *)(void *)((char *)hdr + off); 386 387 return (snl_parse_attrs_raw(ss, nla_head, len, ps, pslen, target)); 388 } 389 390 static inline void 391 snl_parse_fields(struct snl_state *ss, struct nlmsghdr *hdr, int hdrlen __unused, 392 const struct snl_field_parser *ps, int pslen, void *target) 393 { 394 for (int i = 0; i < pslen; i++) { 395 const struct snl_field_parser *fp = &ps[i]; 396 void *src = (char *)hdr + fp->off_in; 397 void *dst = (char *)target + fp->off_out; 398 399 fp->cb(ss, src, dst); 400 } 401 } 402 403 static inline bool 404 snl_parse_header(struct snl_state *ss, void *hdr, int len, 405 const struct snl_hdr_parser *parser, void *target) 406 { 407 /* Extract fields first (if any) */ 408 snl_parse_fields(ss, hdr, parser->hdr_off, parser->fp, parser->fp_size, target); 409 410 struct nlattr *nla_head = (struct nlattr *)(void *)((char *)hdr + parser->hdr_off); 411 bool result = snl_parse_attrs_raw(ss, nla_head, len - parser->hdr_off, 412 parser->np, parser->np_size, target); 413 414 return (result); 415 } 416 417 static inline bool 418 snl_parse_nlmsg(struct snl_state *ss, struct nlmsghdr *hdr, 419 const struct snl_hdr_parser *parser, void *target) 420 { 421 return (snl_parse_header(ss, hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, target)); 422 } 423 424 static inline bool 425 snl_attr_get_flag(struct snl_state *ss __unused, struct nlattr *nla, void *target) 426 { 427 if (NLA_DATA_LEN(nla) == 0) { 428 *((uint8_t *)target) = 1; 429 return (true); 430 } 431 return (false); 432 } 433 434 static inline bool 435 snl_attr_get_uint8(struct snl_state *ss __unused, struct nlattr *nla, 436 const void *arg __unused, void *target) 437 { 438 if (NLA_DATA_LEN(nla) == sizeof(uint8_t)) { 439 *((uint8_t *)target) = *((const uint8_t *)NLA_DATA_CONST(nla)); 440 return (true); 441 } 442 return (false); 443 } 444 445 static inline bool 446 snl_attr_get_uint16(struct snl_state *ss __unused, struct nlattr *nla, 447 const void *arg __unused, void *target) 448 { 449 if (NLA_DATA_LEN(nla) == sizeof(uint16_t)) { 450 *((uint16_t *)target) = *((const uint16_t *)NLA_DATA_CONST(nla)); 451 return (true); 452 } 453 return (false); 454 } 455 456 static inline bool 457 snl_attr_get_uint32(struct snl_state *ss __unused, struct nlattr *nla, 458 const void *arg __unused, void *target) 459 { 460 if (NLA_DATA_LEN(nla) == sizeof(uint32_t)) { 461 *((uint32_t *)target) = *((const uint32_t *)NLA_DATA_CONST(nla)); 462 return (true); 463 } 464 return (false); 465 } 466 467 static inline bool 468 snl_attr_get_uint64(struct snl_state *ss __unused, struct nlattr *nla, 469 const void *arg __unused, void *target) 470 { 471 if (NLA_DATA_LEN(nla) == sizeof(uint64_t)) { 472 memcpy(target, NLA_DATA_CONST(nla), sizeof(uint64_t)); 473 return (true); 474 } 475 return (false); 476 } 477 478 static inline bool 479 snl_attr_get_int8(struct snl_state *ss, struct nlattr *nla, const void *arg, 480 void *target) 481 { 482 return (snl_attr_get_uint8(ss, nla, arg, target)); 483 } 484 485 static inline bool 486 snl_attr_get_int16(struct snl_state *ss, struct nlattr *nla, const void *arg, 487 void *target) 488 { 489 return (snl_attr_get_uint16(ss, nla, arg, target)); 490 } 491 492 static inline bool 493 snl_attr_get_int32(struct snl_state *ss, struct nlattr *nla, const void *arg, 494 void *target) 495 { 496 return (snl_attr_get_uint32(ss, nla, arg, target)); 497 } 498 499 static inline bool 500 snl_attr_get_int64(struct snl_state *ss, struct nlattr *nla, const void *arg, 501 void *target) 502 { 503 return (snl_attr_get_uint64(ss, nla, arg, target)); 504 } 505 506 static inline bool 507 snl_attr_get_string(struct snl_state *ss __unused, struct nlattr *nla, 508 const void *arg __unused, void *target) 509 { 510 size_t maxlen = NLA_DATA_LEN(nla); 511 512 if (strnlen((char *)NLA_DATA(nla), maxlen) < maxlen) { 513 *((char **)target) = (char *)NLA_DATA(nla); 514 return (true); 515 } 516 return (false); 517 } 518 519 static inline bool 520 snl_attr_get_stringn(struct snl_state *ss, struct nlattr *nla, 521 const void *arg __unused, void *target) 522 { 523 int maxlen = NLA_DATA_LEN(nla); 524 525 char *buf = snl_allocz(ss, maxlen + 1); 526 if (buf == NULL) 527 return (false); 528 buf[maxlen] = '\0'; 529 memcpy(buf, NLA_DATA(nla), maxlen); 530 531 *((char **)target) = buf; 532 return (true); 533 } 534 535 static inline bool 536 snl_attr_get_nested(struct snl_state *ss, struct nlattr *nla, const void *arg, void *target) 537 { 538 const struct snl_hdr_parser *p = (const struct snl_hdr_parser *)arg; 539 540 /* Assumes target points to the beginning of the structure */ 541 return (snl_parse_header(ss, NLA_DATA(nla), NLA_DATA_LEN(nla), p, target)); 542 } 543 544 static inline bool 545 snl_attr_get_nla(struct snl_state *ss __unused, struct nlattr *nla, 546 const void *arg __unused, void *target) 547 { 548 *((struct nlattr **)target) = nla; 549 return (true); 550 } 551 552 static inline bool 553 snl_attr_copy_struct(struct snl_state *ss, struct nlattr *nla, 554 const void *arg __unused, void *target) 555 { 556 void *ptr = snl_allocz(ss, NLA_DATA_LEN(nla)); 557 558 if (ptr != NULL) { 559 memcpy(ptr, NLA_DATA(nla), NLA_DATA_LEN(nla)); 560 *((void **)target) = ptr; 561 return (true); 562 } 563 return (false); 564 } 565 566 static inline void 567 snl_field_get_uint8(struct snl_state *ss __unused, void *src, void *target) 568 { 569 *((uint8_t *)target) = *((uint8_t *)src); 570 } 571 572 static inline void 573 snl_field_get_uint16(struct snl_state *ss __unused, void *src, void *target) 574 { 575 *((uint16_t *)target) = *((uint16_t *)src); 576 } 577 578 static inline void 579 snl_field_get_uint32(struct snl_state *ss __unused, void *src, void *target) 580 { 581 *((uint32_t *)target) = *((uint32_t *)src); 582 } 583 584 static inline void 585 snl_field_get_ptr(struct snl_state *ss __unused, void *src, void *target) 586 { 587 *((void **)target) = src; 588 } 589 590 struct snl_errmsg_data { 591 struct nlmsghdr *orig_hdr; 592 int error; 593 uint32_t error_offs; 594 char *error_str; 595 struct nlattr *cookie; 596 }; 597 598 #define _IN(_field) offsetof(struct nlmsgerr, _field) 599 #define _OUT(_field) offsetof(struct snl_errmsg_data, _field) 600 static const struct snl_attr_parser nla_p_errmsg[] = { 601 { .type = NLMSGERR_ATTR_MSG, .off = _OUT(error_str), .cb = snl_attr_get_string }, 602 { .type = NLMSGERR_ATTR_OFFS, .off = _OUT(error_offs), .cb = snl_attr_get_uint32 }, 603 { .type = NLMSGERR_ATTR_COOKIE, .off = _OUT(cookie), .cb = snl_attr_get_nla }, 604 }; 605 606 static const struct snl_field_parser nlf_p_errmsg[] = { 607 { .off_in = _IN(error), .off_out = _OUT(error), .cb = snl_field_get_uint32 }, 608 { .off_in = _IN(msg), .off_out = _OUT(orig_hdr), .cb = snl_field_get_ptr }, 609 }; 610 #undef _IN 611 #undef _OUT 612 SNL_DECLARE_PARSER(snl_errmsg_parser, struct nlmsgerr, nlf_p_errmsg, nla_p_errmsg); 613 614 #define _IN(_field) offsetof(struct nlmsgerr, _field) 615 #define _OUT(_field) offsetof(struct snl_errmsg_data, _field) 616 static const struct snl_attr_parser nla_p_donemsg[] = {}; 617 618 static const struct snl_field_parser nlf_p_donemsg[] = { 619 { .off_in = _IN(error), .off_out = _OUT(error), .cb = snl_field_get_uint32 }, 620 }; 621 #undef _IN 622 #undef _OUT 623 SNL_DECLARE_PARSER(snl_donemsg_parser, struct nlmsgerr, nlf_p_donemsg, nla_p_donemsg); 624 625 static inline bool 626 snl_parse_errmsg(struct snl_state *ss, struct nlmsghdr *hdr, struct snl_errmsg_data *e) 627 { 628 if ((hdr->nlmsg_flags & NLM_F_CAPPED) != 0) 629 return (snl_parse_nlmsg(ss, hdr, &snl_errmsg_parser, e)); 630 631 const struct snl_hdr_parser *ps = &snl_errmsg_parser; 632 struct nlmsgerr *errmsg = (struct nlmsgerr *)(hdr + 1); 633 int hdrlen = sizeof(int) + NLMSG_ALIGN(errmsg->msg.nlmsg_len); 634 struct nlattr *attr_head = (struct nlattr *)(void *)((char *)errmsg + hdrlen); 635 int attr_len = hdr->nlmsg_len - sizeof(struct nlmsghdr) - hdrlen; 636 637 snl_parse_fields(ss, (struct nlmsghdr *)errmsg, hdrlen, ps->fp, ps->fp_size, e); 638 return (snl_parse_attrs_raw(ss, attr_head, attr_len, ps->np, ps->np_size, e)); 639 } 640 641 static inline bool 642 snl_read_reply_code(struct snl_state *ss, uint32_t nlmsg_seq, struct snl_errmsg_data *e) 643 { 644 struct nlmsghdr *hdr = snl_read_reply(ss, nlmsg_seq); 645 646 if (hdr == NULL) { 647 e->error = EINVAL; 648 } else if (hdr->nlmsg_type == NLMSG_ERROR) { 649 if (!snl_parse_errmsg(ss, hdr, e)) 650 e->error = EINVAL; 651 return (e->error == 0); 652 } 653 654 return (false); 655 } 656 657 /* 658 * Assumes e is zeroed 659 */ 660 static inline struct nlmsghdr * 661 snl_read_reply_multi(struct snl_state *ss, uint32_t nlmsg_seq, struct snl_errmsg_data *e) 662 { 663 struct nlmsghdr *hdr = snl_read_reply(ss, nlmsg_seq); 664 665 if (hdr == NULL) { 666 e->error = EINVAL; 667 } else if (hdr->nlmsg_type == NLMSG_ERROR) { 668 if (!snl_parse_errmsg(ss, hdr, e)) 669 e->error = EINVAL; 670 } else if (hdr->nlmsg_type == NLMSG_DONE) { 671 snl_parse_nlmsg(ss, hdr, &snl_donemsg_parser, e); 672 } else 673 return (hdr); 674 675 return (NULL); 676 } 677 678 679 /* writer logic */ 680 struct snl_writer { 681 char *base; 682 uint32_t offset; 683 uint32_t size; 684 struct nlmsghdr *hdr; 685 struct snl_state *ss; 686 bool error; 687 }; 688 689 static inline void 690 snl_init_writer(struct snl_state *ss, struct snl_writer *nw) 691 { 692 nw->size = SNL_WRITER_BUFFER_SIZE; 693 nw->base = snl_allocz(ss, nw->size); 694 if (nw->base == NULL) { 695 nw->error = true; 696 nw->size = 0; 697 } 698 699 nw->offset = 0; 700 nw->hdr = NULL; 701 nw->error = false; 702 nw->ss = ss; 703 } 704 705 static inline bool 706 snl_realloc_msg_buffer(struct snl_writer *nw, size_t sz) 707 { 708 uint32_t new_size = nw->size * 2; 709 710 while (new_size < nw->size + sz) 711 new_size *= 2; 712 713 if (nw->error) 714 return (false); 715 716 void *new_base = snl_allocz(nw->ss, new_size); 717 if (new_base == NULL) { 718 nw->error = true; 719 return (false); 720 } 721 722 memcpy(new_base, nw->base, nw->offset); 723 if (nw->hdr != NULL) { 724 int hdr_off = (char *)(nw->hdr) - nw->base; 725 nw->hdr = (struct nlmsghdr *)(void *)((char *)new_base + hdr_off); 726 } 727 nw->base = new_base; 728 729 return (true); 730 } 731 732 static inline void * 733 snl_reserve_msg_data_raw(struct snl_writer *nw, size_t sz) 734 { 735 sz = NETLINK_ALIGN(sz); 736 737 if (__predict_false(nw->offset + sz > nw->size)) { 738 if (!snl_realloc_msg_buffer(nw, sz)) 739 return (NULL); 740 } 741 742 void *data_ptr = &nw->base[nw->offset]; 743 nw->offset += sz; 744 745 return (data_ptr); 746 } 747 #define snl_reserve_msg_object(_ns, _t) ((_t *)snl_reserve_msg_data_raw(_ns, sizeof(_t))) 748 #define snl_reserve_msg_data(_ns, _sz, _t) ((_t *)snl_reserve_msg_data_raw(_ns, _sz)) 749 750 static inline void * 751 _snl_reserve_msg_attr(struct snl_writer *nw, uint16_t nla_type, uint16_t sz) 752 { 753 sz += sizeof(struct nlattr); 754 755 struct nlattr *nla = snl_reserve_msg_data(nw, sz, struct nlattr); 756 if (__predict_false(nla == NULL)) 757 return (NULL); 758 nla->nla_type = nla_type; 759 nla->nla_len = sz; 760 761 return ((void *)(nla + 1)); 762 } 763 #define snl_reserve_msg_attr(_ns, _at, _t) ((_t *)_snl_reserve_msg_attr(_ns, _at, sizeof(_t))) 764 765 static inline bool 766 snl_add_msg_attr(struct snl_writer *nw, int attr_type, int attr_len, const void *data) 767 { 768 int required_len = NLA_ALIGN(attr_len + sizeof(struct nlattr)); 769 770 if (__predict_false(nw->offset + required_len > nw->size)) { 771 if (!snl_realloc_msg_buffer(nw, required_len)) 772 return (false); 773 } 774 775 struct nlattr *nla = (struct nlattr *)(void *)(&nw->base[nw->offset]); 776 777 nla->nla_len = attr_len + sizeof(struct nlattr); 778 nla->nla_type = attr_type; 779 if (attr_len > 0) { 780 if ((attr_len % 4) != 0) { 781 /* clear padding bytes */ 782 bzero((char *)nla + required_len - 4, 4); 783 } 784 memcpy((nla + 1), data, attr_len); 785 } 786 nw->offset += required_len; 787 return (true); 788 } 789 790 static inline bool 791 snl_add_msg_attr_raw(struct snl_writer *nw, const struct nlattr *nla_src) 792 { 793 int attr_len = nla_src->nla_len - sizeof(struct nlattr); 794 795 assert(attr_len >= 0); 796 797 return (snl_add_msg_attr(nw, nla_src->nla_type, attr_len, (const void *)(nla_src + 1))); 798 } 799 800 static inline bool 801 snl_add_msg_attr_u8(struct snl_writer *nw, int attrtype, uint8_t value) 802 { 803 return (snl_add_msg_attr(nw, attrtype, sizeof(uint8_t), &value)); 804 } 805 806 static inline bool 807 snl_add_msg_attr_u16(struct snl_writer *nw, int attrtype, uint16_t value) 808 { 809 return (snl_add_msg_attr(nw, attrtype, sizeof(uint16_t), &value)); 810 } 811 812 static inline bool 813 snl_add_msg_attr_u32(struct snl_writer *nw, int attrtype, uint32_t value) 814 { 815 return (snl_add_msg_attr(nw, attrtype, sizeof(uint32_t), &value)); 816 } 817 818 static inline bool 819 snl_add_msg_attr_u64(struct snl_writer *nw, int attrtype, uint64_t value) 820 { 821 return (snl_add_msg_attr(nw, attrtype, sizeof(uint64_t), &value)); 822 } 823 824 static inline bool 825 snl_add_msg_attr_s8(struct snl_writer *nw, int attrtype, int8_t value) 826 { 827 return (snl_add_msg_attr(nw, attrtype, sizeof(int8_t), &value)); 828 } 829 830 static inline bool 831 snl_add_msg_attr_s16(struct snl_writer *nw, int attrtype, int16_t value) 832 { 833 return (snl_add_msg_attr(nw, attrtype, sizeof(int16_t), &value)); 834 } 835 836 static inline bool 837 snl_add_msg_attr_s32(struct snl_writer *nw, int attrtype, int32_t value) 838 { 839 return (snl_add_msg_attr(nw, attrtype, sizeof(int32_t), &value)); 840 } 841 842 static inline bool 843 snl_add_msg_attr_s64(struct snl_writer *nw, int attrtype, int64_t value) 844 { 845 return (snl_add_msg_attr(nw, attrtype, sizeof(int64_t), &value)); 846 } 847 848 static inline bool 849 snl_add_msg_attr_flag(struct snl_writer *nw, int attrtype) 850 { 851 return (snl_add_msg_attr(nw, attrtype, 0, NULL)); 852 } 853 854 static inline bool 855 snl_add_msg_attr_string(struct snl_writer *nw, int attrtype, const char *str) 856 { 857 return (snl_add_msg_attr(nw, attrtype, strlen(str) + 1, str)); 858 } 859 860 861 static inline int 862 snl_get_msg_offset(const struct snl_writer *nw) 863 { 864 return (nw->offset - ((char *)nw->hdr - nw->base)); 865 } 866 867 static inline void * 868 _snl_restore_msg_offset(const struct snl_writer *nw, int off) 869 { 870 return ((void *)((char *)nw->hdr + off)); 871 } 872 #define snl_restore_msg_offset(_ns, _off, _t) ((_t *)_snl_restore_msg_offset(_ns, _off)) 873 874 static inline int 875 snl_add_msg_attr_nested(struct snl_writer *nw, int attrtype) 876 { 877 int off = snl_get_msg_offset(nw); 878 struct nlattr *nla = snl_reserve_msg_data(nw, sizeof(struct nlattr), struct nlattr); 879 if (__predict_false(nla == NULL)) 880 return (0); 881 nla->nla_type = attrtype; 882 return (off); 883 } 884 885 static inline void 886 snl_end_attr_nested(const struct snl_writer *nw, int off) 887 { 888 if (!nw->error) { 889 struct nlattr *nla = snl_restore_msg_offset(nw, off, struct nlattr); 890 nla->nla_len = NETLINK_ALIGN(snl_get_msg_offset(nw) - off); 891 } 892 } 893 894 static inline struct nlmsghdr * 895 snl_create_msg_request(struct snl_writer *nw, int nlmsg_type) 896 { 897 assert(nw->hdr == NULL); 898 899 struct nlmsghdr *hdr = snl_reserve_msg_object(nw, struct nlmsghdr); 900 hdr->nlmsg_type = nlmsg_type; 901 hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; 902 nw->hdr = hdr; 903 904 return (hdr); 905 } 906 907 static void 908 snl_abort_msg(struct snl_writer *nw) 909 { 910 if (nw->hdr != NULL) { 911 int offset = (char *)(&nw->base[nw->offset]) - (char *)(nw->hdr); 912 913 nw->offset -= offset; 914 nw->hdr = NULL; 915 } 916 } 917 918 static inline struct nlmsghdr * 919 snl_finalize_msg(struct snl_writer *nw) 920 { 921 if (nw->error) 922 snl_abort_msg(nw); 923 if (nw->hdr != NULL) { 924 struct nlmsghdr *hdr = nw->hdr; 925 926 int offset = (char *)(&nw->base[nw->offset]) - (char *)(nw->hdr); 927 hdr->nlmsg_len = offset; 928 hdr->nlmsg_seq = snl_get_seq(nw->ss); 929 nw->hdr = NULL; 930 931 return (hdr); 932 } 933 return (NULL); 934 } 935 936 static inline bool 937 snl_send_msgs(struct snl_writer *nw) 938 { 939 int offset = nw->offset; 940 941 assert(nw->hdr == NULL); 942 nw->offset = 0; 943 944 return (snl_send(nw->ss, nw->base, offset)); 945 } 946 947 static const struct snl_hdr_parser *snl_all_core_parsers[] = { 948 &snl_errmsg_parser, &snl_donemsg_parser, 949 }; 950 951 #endif 952