1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 4 * 5 * Development of this code funded by Astaro AG (http://www.astaro.com/) 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/init.h> 10 #include <linux/module.h> 11 #include <linux/netlink.h> 12 #include <linux/netfilter.h> 13 #include <linux/if_arp.h> 14 #include <linux/netfilter/nf_tables.h> 15 #include <net/netfilter/nf_tables_core.h> 16 #include <net/netfilter/nf_tables_offload.h> 17 #include <net/netfilter/nf_tables.h> 18 19 struct nft_cmp_expr { 20 struct nft_data data; 21 u8 sreg; 22 u8 len; 23 enum nft_cmp_ops op:8; 24 }; 25 26 void nft_cmp_eval(const struct nft_expr *expr, 27 struct nft_regs *regs, 28 const struct nft_pktinfo *pkt) 29 { 30 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 31 int d; 32 33 d = memcmp(®s->data[priv->sreg], &priv->data, priv->len); 34 switch (priv->op) { 35 case NFT_CMP_EQ: 36 if (d != 0) 37 goto mismatch; 38 break; 39 case NFT_CMP_NEQ: 40 if (d == 0) 41 goto mismatch; 42 break; 43 case NFT_CMP_LT: 44 if (d == 0) 45 goto mismatch; 46 fallthrough; 47 case NFT_CMP_LTE: 48 if (d > 0) 49 goto mismatch; 50 break; 51 case NFT_CMP_GT: 52 if (d == 0) 53 goto mismatch; 54 fallthrough; 55 case NFT_CMP_GTE: 56 if (d < 0) 57 goto mismatch; 58 break; 59 } 60 return; 61 62 mismatch: 63 regs->verdict.code = NFT_BREAK; 64 } 65 66 static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { 67 [NFTA_CMP_SREG] = NLA_POLICY_MAX(NLA_BE32, NFT_REG32_MAX), 68 [NFTA_CMP_OP] = { .type = NLA_U32 }, 69 [NFTA_CMP_DATA] = { .type = NLA_NESTED }, 70 }; 71 72 static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 73 const struct nlattr * const tb[]) 74 { 75 struct nft_cmp_expr *priv = nft_expr_priv(expr); 76 struct nft_data_desc desc = { 77 .type = NFT_DATA_VALUE, 78 .size = sizeof(priv->data), 79 }; 80 int err; 81 82 err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]); 83 if (err < 0) 84 return err; 85 86 err = nft_parse_register_load(ctx, tb[NFTA_CMP_SREG], &priv->sreg, desc.len); 87 if (err < 0) 88 return err; 89 90 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 91 priv->len = desc.len; 92 return 0; 93 } 94 95 static int nft_cmp_dump(struct sk_buff *skb, 96 const struct nft_expr *expr, bool reset) 97 { 98 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 99 100 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 101 goto nla_put_failure; 102 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 103 goto nla_put_failure; 104 105 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 106 NFT_DATA_VALUE, priv->len) < 0) 107 goto nla_put_failure; 108 return 0; 109 110 nla_put_failure: 111 return -1; 112 } 113 114 union nft_cmp_offload_data { 115 u16 val16; 116 u32 val32; 117 u64 val64; 118 }; 119 120 static void nft_payload_n2h(union nft_cmp_offload_data *data, 121 const u8 *val, u32 len) 122 { 123 switch (len) { 124 case 2: 125 data->val16 = ntohs(*((__be16 *)val)); 126 break; 127 case 4: 128 data->val32 = ntohl(*((__be32 *)val)); 129 break; 130 case 8: 131 data->val64 = be64_to_cpu(*((__be64 *)val)); 132 break; 133 default: 134 WARN_ON_ONCE(1); 135 break; 136 } 137 } 138 139 static int __nft_cmp_offload(struct nft_offload_ctx *ctx, 140 struct nft_flow_rule *flow, 141 const struct nft_cmp_expr *priv) 142 { 143 struct nft_offload_reg *reg = &ctx->regs[priv->sreg]; 144 union nft_cmp_offload_data _data, _datamask; 145 u8 *mask = (u8 *)&flow->match.mask; 146 u8 *key = (u8 *)&flow->match.key; 147 u8 *data, *datamask; 148 149 if (priv->op != NFT_CMP_EQ || priv->len > reg->len) 150 return -EOPNOTSUPP; 151 152 if (reg->flags & NFT_OFFLOAD_F_NETWORK2HOST) { 153 nft_payload_n2h(&_data, (u8 *)&priv->data, reg->len); 154 nft_payload_n2h(&_datamask, (u8 *)®->mask, reg->len); 155 data = (u8 *)&_data; 156 datamask = (u8 *)&_datamask; 157 } else { 158 data = (u8 *)&priv->data; 159 datamask = (u8 *)®->mask; 160 } 161 162 memcpy(key + reg->offset, data, reg->len); 163 memcpy(mask + reg->offset, datamask, reg->len); 164 165 flow->match.dissector.used_keys |= BIT_ULL(reg->key); 166 flow->match.dissector.offset[reg->key] = reg->base_offset; 167 168 if (reg->key == FLOW_DISSECTOR_KEY_META && 169 reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) && 170 nft_reg_load16(priv->data.data) != ARPHRD_ETHER) 171 return -EOPNOTSUPP; 172 173 nft_offload_update_dependency(ctx, &priv->data, reg->len); 174 175 return 0; 176 } 177 178 static int nft_cmp_offload(struct nft_offload_ctx *ctx, 179 struct nft_flow_rule *flow, 180 const struct nft_expr *expr) 181 { 182 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 183 184 return __nft_cmp_offload(ctx, flow, priv); 185 } 186 187 static const struct nft_expr_ops nft_cmp_ops = { 188 .type = &nft_cmp_type, 189 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 190 .eval = nft_cmp_eval, 191 .init = nft_cmp_init, 192 .dump = nft_cmp_dump, 193 .offload = nft_cmp_offload, 194 }; 195 196 /* Calculate the mask for the nft_cmp_fast expression. On big endian the 197 * mask needs to include the *upper* bytes when interpreting that data as 198 * something smaller than the full u32, therefore a cpu_to_le32 is done. 199 */ 200 static u32 nft_cmp_fast_mask(unsigned int len) 201 { 202 __le32 mask = cpu_to_le32(~0U >> (sizeof_field(struct nft_cmp_fast_expr, 203 data) * BITS_PER_BYTE - len)); 204 205 return (__force u32)mask; 206 } 207 208 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 209 const struct nft_expr *expr, 210 const struct nlattr * const tb[]) 211 { 212 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 213 struct nft_data data; 214 struct nft_data_desc desc = { 215 .type = NFT_DATA_VALUE, 216 .size = sizeof(data), 217 }; 218 int err; 219 220 err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); 221 if (err < 0) 222 return err; 223 224 err = nft_parse_register_load(ctx, tb[NFTA_CMP_SREG], &priv->sreg, desc.len); 225 if (err < 0) 226 return err; 227 228 desc.len *= BITS_PER_BYTE; 229 230 priv->mask = nft_cmp_fast_mask(desc.len); 231 priv->data = data.data[0] & priv->mask; 232 priv->len = desc.len; 233 priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; 234 return 0; 235 } 236 237 static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx, 238 struct nft_flow_rule *flow, 239 const struct nft_expr *expr) 240 { 241 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 242 struct nft_cmp_expr cmp = { 243 .data = { 244 .data = { 245 [0] = priv->data, 246 }, 247 }, 248 .sreg = priv->sreg, 249 .len = priv->len / BITS_PER_BYTE, 250 .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, 251 }; 252 253 return __nft_cmp_offload(ctx, flow, &cmp); 254 } 255 256 static int nft_cmp_fast_dump(struct sk_buff *skb, 257 const struct nft_expr *expr, bool reset) 258 { 259 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 260 enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; 261 struct nft_data data; 262 263 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 264 goto nla_put_failure; 265 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op))) 266 goto nla_put_failure; 267 268 data.data[0] = priv->data; 269 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 270 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 271 goto nla_put_failure; 272 return 0; 273 274 nla_put_failure: 275 return -1; 276 } 277 278 const struct nft_expr_ops nft_cmp_fast_ops = { 279 .type = &nft_cmp_type, 280 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 281 .eval = NULL, /* inlined */ 282 .init = nft_cmp_fast_init, 283 .dump = nft_cmp_fast_dump, 284 .offload = nft_cmp_fast_offload, 285 }; 286 287 static u32 nft_cmp_mask(u32 bitlen) 288 { 289 return (__force u32)cpu_to_le32(~0U >> (sizeof(u32) * BITS_PER_BYTE - bitlen)); 290 } 291 292 static void nft_cmp16_fast_mask(struct nft_data *data, unsigned int bitlen) 293 { 294 int len = bitlen / BITS_PER_BYTE; 295 int i, words = len / sizeof(u32); 296 297 for (i = 0; i < words; i++) { 298 data->data[i] = 0xffffffff; 299 bitlen -= sizeof(u32) * BITS_PER_BYTE; 300 } 301 302 if (len % sizeof(u32)) 303 data->data[i++] = nft_cmp_mask(bitlen); 304 305 for (; i < 4; i++) 306 data->data[i] = 0; 307 } 308 309 static int nft_cmp16_fast_init(const struct nft_ctx *ctx, 310 const struct nft_expr *expr, 311 const struct nlattr * const tb[]) 312 { 313 struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); 314 struct nft_data_desc desc = { 315 .type = NFT_DATA_VALUE, 316 .size = sizeof(priv->data), 317 }; 318 int err; 319 320 err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]); 321 if (err < 0) 322 return err; 323 324 err = nft_parse_register_load(ctx, tb[NFTA_CMP_SREG], &priv->sreg, desc.len); 325 if (err < 0) 326 return err; 327 328 nft_cmp16_fast_mask(&priv->mask, desc.len * BITS_PER_BYTE); 329 priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; 330 priv->len = desc.len; 331 332 return 0; 333 } 334 335 static int nft_cmp16_fast_offload(struct nft_offload_ctx *ctx, 336 struct nft_flow_rule *flow, 337 const struct nft_expr *expr) 338 { 339 const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); 340 struct nft_cmp_expr cmp = { 341 .data = priv->data, 342 .sreg = priv->sreg, 343 .len = priv->len, 344 .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, 345 }; 346 347 return __nft_cmp_offload(ctx, flow, &cmp); 348 } 349 350 static int nft_cmp16_fast_dump(struct sk_buff *skb, 351 const struct nft_expr *expr, bool reset) 352 { 353 const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); 354 enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; 355 356 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 357 goto nla_put_failure; 358 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op))) 359 goto nla_put_failure; 360 361 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 362 NFT_DATA_VALUE, priv->len) < 0) 363 goto nla_put_failure; 364 return 0; 365 366 nla_put_failure: 367 return -1; 368 } 369 370 371 const struct nft_expr_ops nft_cmp16_fast_ops = { 372 .type = &nft_cmp_type, 373 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp16_fast_expr)), 374 .eval = NULL, /* inlined */ 375 .init = nft_cmp16_fast_init, 376 .dump = nft_cmp16_fast_dump, 377 .offload = nft_cmp16_fast_offload, 378 }; 379 380 static const struct nft_expr_ops * 381 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 382 { 383 struct nft_data data; 384 struct nft_data_desc desc = { 385 .type = NFT_DATA_VALUE, 386 .size = sizeof(data), 387 }; 388 enum nft_cmp_ops op; 389 u8 sreg; 390 int err; 391 392 if (tb[NFTA_CMP_SREG] == NULL || 393 tb[NFTA_CMP_OP] == NULL || 394 tb[NFTA_CMP_DATA] == NULL) 395 return ERR_PTR(-EINVAL); 396 397 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 398 switch (op) { 399 case NFT_CMP_EQ: 400 case NFT_CMP_NEQ: 401 case NFT_CMP_LT: 402 case NFT_CMP_LTE: 403 case NFT_CMP_GT: 404 case NFT_CMP_GTE: 405 break; 406 default: 407 return ERR_PTR(-EINVAL); 408 } 409 410 err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]); 411 if (err < 0) 412 return ERR_PTR(err); 413 414 sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); 415 416 if (op == NFT_CMP_EQ || op == NFT_CMP_NEQ) { 417 if (desc.len <= sizeof(u32)) 418 return &nft_cmp_fast_ops; 419 else if (desc.len <= sizeof(data) && 420 ((sreg >= NFT_REG_1 && sreg <= NFT_REG_4) || 421 (sreg >= NFT_REG32_00 && sreg <= NFT_REG32_12 && sreg % 2 == 0))) 422 return &nft_cmp16_fast_ops; 423 } 424 return &nft_cmp_ops; 425 } 426 427 struct nft_expr_type nft_cmp_type __read_mostly = { 428 .name = "cmp", 429 .select_ops = nft_cmp_select_ops, 430 .policy = nft_cmp_policy, 431 .maxattr = NFTA_CMP_MAX, 432 .owner = THIS_MODULE, 433 }; 434