1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> 4 * 5 * Development of this code funded by Astaro AG (http://www.astaro.com/) 6 */ 7 8 #include <asm/unaligned.h> 9 #include <linux/kernel.h> 10 #include <linux/netlink.h> 11 #include <linux/netfilter.h> 12 #include <linux/netfilter/nf_tables.h> 13 #include <linux/sctp.h> 14 #include <net/netfilter/nf_tables_core.h> 15 #include <net/netfilter/nf_tables.h> 16 #include <net/sctp/sctp.h> 17 #include <net/tcp.h> 18 19 struct nft_exthdr { 20 u8 type; 21 u8 offset; 22 u8 len; 23 u8 op; 24 u8 dreg; 25 u8 sreg; 26 u8 flags; 27 }; 28 29 static unsigned int optlen(const u8 *opt, unsigned int offset) 30 { 31 /* Beware zero-length options: make finite progress */ 32 if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0) 33 return 1; 34 else 35 return opt[offset + 1]; 36 } 37 38 static void nft_exthdr_ipv6_eval(const struct nft_expr *expr, 39 struct nft_regs *regs, 40 const struct nft_pktinfo *pkt) 41 { 42 struct nft_exthdr *priv = nft_expr_priv(expr); 43 u32 *dest = ®s->data[priv->dreg]; 44 unsigned int offset = 0; 45 int err; 46 47 if (pkt->skb->protocol != htons(ETH_P_IPV6)) 48 goto err; 49 50 err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL); 51 if (priv->flags & NFT_EXTHDR_F_PRESENT) { 52 nft_reg_store8(dest, err >= 0); 53 return; 54 } else if (err < 0) { 55 goto err; 56 } 57 offset += priv->offset; 58 59 dest[priv->len / NFT_REG32_SIZE] = 0; 60 if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0) 61 goto err; 62 return; 63 err: 64 regs->verdict.code = NFT_BREAK; 65 } 66 67 /* find the offset to specified option. 68 * 69 * If target header is found, its offset is set in *offset and return option 70 * number. Otherwise, return negative error. 71 * 72 * If the first fragment doesn't contain the End of Options it is considered 73 * invalid. 74 */ 75 static int ipv4_find_option(struct net *net, struct sk_buff *skb, 76 unsigned int *offset, int target) 77 { 78 unsigned char optbuf[sizeof(struct ip_options) + 40]; 79 struct ip_options *opt = (struct ip_options *)optbuf; 80 struct iphdr *iph, _iph; 81 unsigned int start; 82 bool found = false; 83 __be32 info; 84 int optlen; 85 86 iph = skb_header_pointer(skb, 0, sizeof(_iph), &_iph); 87 if (!iph) 88 return -EBADMSG; 89 start = sizeof(struct iphdr); 90 91 optlen = iph->ihl * 4 - (int)sizeof(struct iphdr); 92 if (optlen <= 0) 93 return -ENOENT; 94 95 memset(opt, 0, sizeof(struct ip_options)); 96 /* Copy the options since __ip_options_compile() modifies 97 * the options. 98 */ 99 if (skb_copy_bits(skb, start, opt->__data, optlen)) 100 return -EBADMSG; 101 opt->optlen = optlen; 102 103 if (__ip_options_compile(net, opt, NULL, &info)) 104 return -EBADMSG; 105 106 switch (target) { 107 case IPOPT_SSRR: 108 case IPOPT_LSRR: 109 if (!opt->srr) 110 break; 111 found = target == IPOPT_SSRR ? opt->is_strictroute : 112 !opt->is_strictroute; 113 if (found) 114 *offset = opt->srr + start; 115 break; 116 case IPOPT_RR: 117 if (!opt->rr) 118 break; 119 *offset = opt->rr + start; 120 found = true; 121 break; 122 case IPOPT_RA: 123 if (!opt->router_alert) 124 break; 125 *offset = opt->router_alert + start; 126 found = true; 127 break; 128 default: 129 return -EOPNOTSUPP; 130 } 131 return found ? target : -ENOENT; 132 } 133 134 static void nft_exthdr_ipv4_eval(const struct nft_expr *expr, 135 struct nft_regs *regs, 136 const struct nft_pktinfo *pkt) 137 { 138 struct nft_exthdr *priv = nft_expr_priv(expr); 139 u32 *dest = ®s->data[priv->dreg]; 140 struct sk_buff *skb = pkt->skb; 141 unsigned int offset; 142 int err; 143 144 if (skb->protocol != htons(ETH_P_IP)) 145 goto err; 146 147 err = ipv4_find_option(nft_net(pkt), skb, &offset, priv->type); 148 if (priv->flags & NFT_EXTHDR_F_PRESENT) { 149 nft_reg_store8(dest, err >= 0); 150 return; 151 } else if (err < 0) { 152 goto err; 153 } 154 offset += priv->offset; 155 156 dest[priv->len / NFT_REG32_SIZE] = 0; 157 if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0) 158 goto err; 159 return; 160 err: 161 regs->verdict.code = NFT_BREAK; 162 } 163 164 static void * 165 nft_tcp_header_pointer(const struct nft_pktinfo *pkt, 166 unsigned int len, void *buffer, unsigned int *tcphdr_len) 167 { 168 struct tcphdr *tcph; 169 170 if (pkt->tprot != IPPROTO_TCP || pkt->fragoff) 171 return NULL; 172 173 tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt), sizeof(*tcph), buffer); 174 if (!tcph) 175 return NULL; 176 177 *tcphdr_len = __tcp_hdrlen(tcph); 178 if (*tcphdr_len < sizeof(*tcph) || *tcphdr_len > len) 179 return NULL; 180 181 return skb_header_pointer(pkt->skb, nft_thoff(pkt), *tcphdr_len, buffer); 182 } 183 184 static void nft_exthdr_tcp_eval(const struct nft_expr *expr, 185 struct nft_regs *regs, 186 const struct nft_pktinfo *pkt) 187 { 188 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE]; 189 struct nft_exthdr *priv = nft_expr_priv(expr); 190 unsigned int i, optl, tcphdr_len, offset; 191 u32 *dest = ®s->data[priv->dreg]; 192 struct tcphdr *tcph; 193 u8 *opt; 194 195 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len); 196 if (!tcph) 197 goto err; 198 199 opt = (u8 *)tcph; 200 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) { 201 optl = optlen(opt, i); 202 203 if (priv->type != opt[i]) 204 continue; 205 206 if (i + optl > tcphdr_len || priv->len + priv->offset > optl) 207 goto err; 208 209 offset = i + priv->offset; 210 if (priv->flags & NFT_EXTHDR_F_PRESENT) { 211 *dest = 1; 212 } else { 213 dest[priv->len / NFT_REG32_SIZE] = 0; 214 memcpy(dest, opt + offset, priv->len); 215 } 216 217 return; 218 } 219 220 err: 221 if (priv->flags & NFT_EXTHDR_F_PRESENT) 222 *dest = 0; 223 else 224 regs->verdict.code = NFT_BREAK; 225 } 226 227 static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr, 228 struct nft_regs *regs, 229 const struct nft_pktinfo *pkt) 230 { 231 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE]; 232 struct nft_exthdr *priv = nft_expr_priv(expr); 233 unsigned int i, optl, tcphdr_len, offset; 234 struct tcphdr *tcph; 235 u8 *opt; 236 237 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len); 238 if (!tcph) 239 goto err; 240 241 opt = (u8 *)tcph; 242 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) { 243 union { 244 __be16 v16; 245 __be32 v32; 246 } old, new; 247 248 optl = optlen(opt, i); 249 250 if (priv->type != opt[i]) 251 continue; 252 253 if (i + optl > tcphdr_len || priv->len + priv->offset > optl) 254 goto err; 255 256 if (skb_ensure_writable(pkt->skb, 257 nft_thoff(pkt) + i + priv->len)) 258 goto err; 259 260 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, 261 &tcphdr_len); 262 if (!tcph) 263 goto err; 264 265 offset = i + priv->offset; 266 267 switch (priv->len) { 268 case 2: 269 old.v16 = (__force __be16)get_unaligned((u16 *)(opt + offset)); 270 new.v16 = (__force __be16)nft_reg_load16( 271 ®s->data[priv->sreg]); 272 273 switch (priv->type) { 274 case TCPOPT_MSS: 275 /* increase can cause connection to stall */ 276 if (ntohs(old.v16) <= ntohs(new.v16)) 277 return; 278 break; 279 } 280 281 if (old.v16 == new.v16) 282 return; 283 284 put_unaligned(new.v16, (__be16*)(opt + offset)); 285 inet_proto_csum_replace2(&tcph->check, pkt->skb, 286 old.v16, new.v16, false); 287 break; 288 case 4: 289 new.v32 = nft_reg_load_be32(®s->data[priv->sreg]); 290 old.v32 = (__force __be32)get_unaligned((u32 *)(opt + offset)); 291 292 if (old.v32 == new.v32) 293 return; 294 295 put_unaligned(new.v32, (__be32*)(opt + offset)); 296 inet_proto_csum_replace4(&tcph->check, pkt->skb, 297 old.v32, new.v32, false); 298 break; 299 default: 300 WARN_ON_ONCE(1); 301 break; 302 } 303 304 return; 305 } 306 return; 307 err: 308 regs->verdict.code = NFT_BREAK; 309 } 310 311 static void nft_exthdr_tcp_strip_eval(const struct nft_expr *expr, 312 struct nft_regs *regs, 313 const struct nft_pktinfo *pkt) 314 { 315 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE]; 316 struct nft_exthdr *priv = nft_expr_priv(expr); 317 unsigned int i, tcphdr_len, optl; 318 struct tcphdr *tcph; 319 u8 *opt; 320 321 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len); 322 if (!tcph) 323 goto err; 324 325 if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len)) 326 goto drop; 327 328 opt = (u8 *)nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len); 329 if (!opt) 330 goto err; 331 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) { 332 unsigned int j; 333 334 optl = optlen(opt, i); 335 if (priv->type != opt[i]) 336 continue; 337 338 if (i + optl > tcphdr_len) 339 goto drop; 340 341 for (j = 0; j < optl; ++j) { 342 u16 n = TCPOPT_NOP; 343 u16 o = opt[i+j]; 344 345 if ((i + j) % 2 == 0) { 346 o <<= 8; 347 n <<= 8; 348 } 349 inet_proto_csum_replace2(&tcph->check, pkt->skb, htons(o), 350 htons(n), false); 351 } 352 memset(opt + i, TCPOPT_NOP, optl); 353 return; 354 } 355 356 /* option not found, continue. This allows to do multiple 357 * option removals per rule. 358 */ 359 return; 360 err: 361 regs->verdict.code = NFT_BREAK; 362 return; 363 drop: 364 /* can't remove, no choice but to drop */ 365 regs->verdict.code = NF_DROP; 366 } 367 368 static void nft_exthdr_sctp_eval(const struct nft_expr *expr, 369 struct nft_regs *regs, 370 const struct nft_pktinfo *pkt) 371 { 372 unsigned int offset = nft_thoff(pkt) + sizeof(struct sctphdr); 373 struct nft_exthdr *priv = nft_expr_priv(expr); 374 u32 *dest = ®s->data[priv->dreg]; 375 const struct sctp_chunkhdr *sch; 376 struct sctp_chunkhdr _sch; 377 378 if (pkt->tprot != IPPROTO_SCTP) 379 goto err; 380 381 do { 382 sch = skb_header_pointer(pkt->skb, offset, sizeof(_sch), &_sch); 383 if (!sch || !sch->length) 384 break; 385 386 if (sch->type == priv->type) { 387 if (priv->flags & NFT_EXTHDR_F_PRESENT) { 388 nft_reg_store8(dest, true); 389 return; 390 } 391 if (priv->offset + priv->len > ntohs(sch->length) || 392 offset + ntohs(sch->length) > pkt->skb->len) 393 break; 394 395 dest[priv->len / NFT_REG32_SIZE] = 0; 396 if (skb_copy_bits(pkt->skb, offset + priv->offset, 397 dest, priv->len) < 0) 398 break; 399 return; 400 } 401 offset += SCTP_PAD4(ntohs(sch->length)); 402 } while (offset < pkt->skb->len); 403 err: 404 if (priv->flags & NFT_EXTHDR_F_PRESENT) 405 nft_reg_store8(dest, false); 406 else 407 regs->verdict.code = NFT_BREAK; 408 } 409 410 static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = { 411 [NFTA_EXTHDR_DREG] = { .type = NLA_U32 }, 412 [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 }, 413 [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 }, 414 [NFTA_EXTHDR_LEN] = { .type = NLA_U32 }, 415 [NFTA_EXTHDR_FLAGS] = { .type = NLA_U32 }, 416 [NFTA_EXTHDR_OP] = { .type = NLA_U32 }, 417 [NFTA_EXTHDR_SREG] = { .type = NLA_U32 }, 418 }; 419 420 static int nft_exthdr_init(const struct nft_ctx *ctx, 421 const struct nft_expr *expr, 422 const struct nlattr * const tb[]) 423 { 424 struct nft_exthdr *priv = nft_expr_priv(expr); 425 u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6; 426 int err; 427 428 if (!tb[NFTA_EXTHDR_DREG] || 429 !tb[NFTA_EXTHDR_TYPE] || 430 !tb[NFTA_EXTHDR_OFFSET] || 431 !tb[NFTA_EXTHDR_LEN]) 432 return -EINVAL; 433 434 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset); 435 if (err < 0) 436 return err; 437 438 err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len); 439 if (err < 0) 440 return err; 441 442 if (tb[NFTA_EXTHDR_FLAGS]) { 443 err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags); 444 if (err < 0) 445 return err; 446 447 if (flags & ~NFT_EXTHDR_F_PRESENT) 448 return -EINVAL; 449 } 450 451 if (tb[NFTA_EXTHDR_OP]) { 452 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op); 453 if (err < 0) 454 return err; 455 } 456 457 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]); 458 priv->offset = offset; 459 priv->len = len; 460 priv->flags = flags; 461 priv->op = op; 462 463 return nft_parse_register_store(ctx, tb[NFTA_EXTHDR_DREG], 464 &priv->dreg, NULL, NFT_DATA_VALUE, 465 priv->len); 466 } 467 468 static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx, 469 const struct nft_expr *expr, 470 const struct nlattr * const tb[]) 471 { 472 struct nft_exthdr *priv = nft_expr_priv(expr); 473 u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6; 474 int err; 475 476 if (!tb[NFTA_EXTHDR_SREG] || 477 !tb[NFTA_EXTHDR_TYPE] || 478 !tb[NFTA_EXTHDR_OFFSET] || 479 !tb[NFTA_EXTHDR_LEN]) 480 return -EINVAL; 481 482 if (tb[NFTA_EXTHDR_DREG] || tb[NFTA_EXTHDR_FLAGS]) 483 return -EINVAL; 484 485 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset); 486 if (err < 0) 487 return err; 488 489 err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len); 490 if (err < 0) 491 return err; 492 493 if (offset < 2) 494 return -EOPNOTSUPP; 495 496 switch (len) { 497 case 2: break; 498 case 4: break; 499 default: 500 return -EOPNOTSUPP; 501 } 502 503 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op); 504 if (err < 0) 505 return err; 506 507 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]); 508 priv->offset = offset; 509 priv->len = len; 510 priv->flags = flags; 511 priv->op = op; 512 513 return nft_parse_register_load(tb[NFTA_EXTHDR_SREG], &priv->sreg, 514 priv->len); 515 } 516 517 static int nft_exthdr_tcp_strip_init(const struct nft_ctx *ctx, 518 const struct nft_expr *expr, 519 const struct nlattr * const tb[]) 520 { 521 struct nft_exthdr *priv = nft_expr_priv(expr); 522 523 if (tb[NFTA_EXTHDR_SREG] || 524 tb[NFTA_EXTHDR_DREG] || 525 tb[NFTA_EXTHDR_FLAGS] || 526 tb[NFTA_EXTHDR_OFFSET] || 527 tb[NFTA_EXTHDR_LEN]) 528 return -EINVAL; 529 530 if (!tb[NFTA_EXTHDR_TYPE]) 531 return -EINVAL; 532 533 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]); 534 priv->op = NFT_EXTHDR_OP_TCPOPT; 535 536 return 0; 537 } 538 539 static int nft_exthdr_ipv4_init(const struct nft_ctx *ctx, 540 const struct nft_expr *expr, 541 const struct nlattr * const tb[]) 542 { 543 struct nft_exthdr *priv = nft_expr_priv(expr); 544 int err = nft_exthdr_init(ctx, expr, tb); 545 546 if (err < 0) 547 return err; 548 549 switch (priv->type) { 550 case IPOPT_SSRR: 551 case IPOPT_LSRR: 552 case IPOPT_RR: 553 case IPOPT_RA: 554 break; 555 default: 556 return -EOPNOTSUPP; 557 } 558 return 0; 559 } 560 561 static int nft_exthdr_dump_common(struct sk_buff *skb, const struct nft_exthdr *priv) 562 { 563 if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type)) 564 goto nla_put_failure; 565 if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset))) 566 goto nla_put_failure; 567 if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len))) 568 goto nla_put_failure; 569 if (nla_put_be32(skb, NFTA_EXTHDR_FLAGS, htonl(priv->flags))) 570 goto nla_put_failure; 571 if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op))) 572 goto nla_put_failure; 573 return 0; 574 575 nla_put_failure: 576 return -1; 577 } 578 579 static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr) 580 { 581 const struct nft_exthdr *priv = nft_expr_priv(expr); 582 583 if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg)) 584 return -1; 585 586 return nft_exthdr_dump_common(skb, priv); 587 } 588 589 static int nft_exthdr_dump_set(struct sk_buff *skb, const struct nft_expr *expr) 590 { 591 const struct nft_exthdr *priv = nft_expr_priv(expr); 592 593 if (nft_dump_register(skb, NFTA_EXTHDR_SREG, priv->sreg)) 594 return -1; 595 596 return nft_exthdr_dump_common(skb, priv); 597 } 598 599 static int nft_exthdr_dump_strip(struct sk_buff *skb, const struct nft_expr *expr) 600 { 601 const struct nft_exthdr *priv = nft_expr_priv(expr); 602 603 return nft_exthdr_dump_common(skb, priv); 604 } 605 606 static bool nft_exthdr_reduce(struct nft_regs_track *track, 607 const struct nft_expr *expr) 608 { 609 const struct nft_exthdr *priv = nft_expr_priv(expr); 610 const struct nft_exthdr *exthdr; 611 612 if (!nft_reg_track_cmp(track, expr, priv->dreg)) { 613 nft_reg_track_update(track, expr, priv->dreg, priv->len); 614 return false; 615 } 616 617 exthdr = nft_expr_priv(track->regs[priv->dreg].selector); 618 if (priv->type != exthdr->type || 619 priv->op != exthdr->op || 620 priv->flags != exthdr->flags || 621 priv->offset != exthdr->offset || 622 priv->len != exthdr->len) { 623 nft_reg_track_update(track, expr, priv->dreg, priv->len); 624 return false; 625 } 626 627 if (!track->regs[priv->dreg].bitwise) 628 return true; 629 630 return nft_expr_reduce_bitwise(track, expr); 631 } 632 633 static const struct nft_expr_ops nft_exthdr_ipv6_ops = { 634 .type = &nft_exthdr_type, 635 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), 636 .eval = nft_exthdr_ipv6_eval, 637 .init = nft_exthdr_init, 638 .dump = nft_exthdr_dump, 639 .reduce = nft_exthdr_reduce, 640 }; 641 642 static const struct nft_expr_ops nft_exthdr_ipv4_ops = { 643 .type = &nft_exthdr_type, 644 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), 645 .eval = nft_exthdr_ipv4_eval, 646 .init = nft_exthdr_ipv4_init, 647 .dump = nft_exthdr_dump, 648 .reduce = nft_exthdr_reduce, 649 }; 650 651 static const struct nft_expr_ops nft_exthdr_tcp_ops = { 652 .type = &nft_exthdr_type, 653 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), 654 .eval = nft_exthdr_tcp_eval, 655 .init = nft_exthdr_init, 656 .dump = nft_exthdr_dump, 657 .reduce = nft_exthdr_reduce, 658 }; 659 660 static const struct nft_expr_ops nft_exthdr_tcp_set_ops = { 661 .type = &nft_exthdr_type, 662 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), 663 .eval = nft_exthdr_tcp_set_eval, 664 .init = nft_exthdr_tcp_set_init, 665 .dump = nft_exthdr_dump_set, 666 .reduce = NFT_REDUCE_READONLY, 667 }; 668 669 static const struct nft_expr_ops nft_exthdr_tcp_strip_ops = { 670 .type = &nft_exthdr_type, 671 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), 672 .eval = nft_exthdr_tcp_strip_eval, 673 .init = nft_exthdr_tcp_strip_init, 674 .dump = nft_exthdr_dump_strip, 675 .reduce = NFT_REDUCE_READONLY, 676 }; 677 678 static const struct nft_expr_ops nft_exthdr_sctp_ops = { 679 .type = &nft_exthdr_type, 680 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), 681 .eval = nft_exthdr_sctp_eval, 682 .init = nft_exthdr_init, 683 .dump = nft_exthdr_dump, 684 .reduce = nft_exthdr_reduce, 685 }; 686 687 static const struct nft_expr_ops * 688 nft_exthdr_select_ops(const struct nft_ctx *ctx, 689 const struct nlattr * const tb[]) 690 { 691 u32 op; 692 693 if (!tb[NFTA_EXTHDR_OP]) 694 return &nft_exthdr_ipv6_ops; 695 696 if (tb[NFTA_EXTHDR_SREG] && tb[NFTA_EXTHDR_DREG]) 697 return ERR_PTR(-EOPNOTSUPP); 698 699 op = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OP])); 700 switch (op) { 701 case NFT_EXTHDR_OP_TCPOPT: 702 if (tb[NFTA_EXTHDR_SREG]) 703 return &nft_exthdr_tcp_set_ops; 704 if (tb[NFTA_EXTHDR_DREG]) 705 return &nft_exthdr_tcp_ops; 706 return &nft_exthdr_tcp_strip_ops; 707 case NFT_EXTHDR_OP_IPV6: 708 if (tb[NFTA_EXTHDR_DREG]) 709 return &nft_exthdr_ipv6_ops; 710 break; 711 case NFT_EXTHDR_OP_IPV4: 712 if (ctx->family != NFPROTO_IPV6) { 713 if (tb[NFTA_EXTHDR_DREG]) 714 return &nft_exthdr_ipv4_ops; 715 } 716 break; 717 case NFT_EXTHDR_OP_SCTP: 718 if (tb[NFTA_EXTHDR_DREG]) 719 return &nft_exthdr_sctp_ops; 720 break; 721 } 722 723 return ERR_PTR(-EOPNOTSUPP); 724 } 725 726 struct nft_expr_type nft_exthdr_type __read_mostly = { 727 .name = "exthdr", 728 .select_ops = nft_exthdr_select_ops, 729 .policy = nft_exthdr_policy, 730 .maxattr = NFTA_EXTHDR_MAX, 731 .owner = THIS_MODULE, 732 }; 733