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
nft_cmp_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)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] = { .type = NLA_U32 },
68 [NFTA_CMP_OP] = { .type = NLA_U32 },
69 [NFTA_CMP_DATA] = { .type = NLA_NESTED },
70 };
71
nft_cmp_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])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(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
nft_cmp_dump(struct sk_buff * skb,const struct nft_expr * expr)95 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr)
96 {
97 const struct nft_cmp_expr *priv = nft_expr_priv(expr);
98
99 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
100 goto nla_put_failure;
101 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op)))
102 goto nla_put_failure;
103
104 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data,
105 NFT_DATA_VALUE, priv->len) < 0)
106 goto nla_put_failure;
107 return 0;
108
109 nla_put_failure:
110 return -1;
111 }
112
113 union nft_cmp_offload_data {
114 u16 val16;
115 u32 val32;
116 u64 val64;
117 };
118
nft_payload_n2h(union nft_cmp_offload_data * data,const u8 * val,u32 len)119 static void nft_payload_n2h(union nft_cmp_offload_data *data,
120 const u8 *val, u32 len)
121 {
122 switch (len) {
123 case 2:
124 data->val16 = ntohs(*((__be16 *)val));
125 break;
126 case 4:
127 data->val32 = ntohl(*((__be32 *)val));
128 break;
129 case 8:
130 data->val64 = be64_to_cpu(*((__be64 *)val));
131 break;
132 default:
133 WARN_ON_ONCE(1);
134 break;
135 }
136 }
137
__nft_cmp_offload(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_cmp_expr * priv)138 static int __nft_cmp_offload(struct nft_offload_ctx *ctx,
139 struct nft_flow_rule *flow,
140 const struct nft_cmp_expr *priv)
141 {
142 struct nft_offload_reg *reg = &ctx->regs[priv->sreg];
143 union nft_cmp_offload_data _data, _datamask;
144 u8 *mask = (u8 *)&flow->match.mask;
145 u8 *key = (u8 *)&flow->match.key;
146 u8 *data, *datamask;
147
148 if (priv->op != NFT_CMP_EQ || priv->len > reg->len)
149 return -EOPNOTSUPP;
150
151 if (reg->flags & NFT_OFFLOAD_F_NETWORK2HOST) {
152 nft_payload_n2h(&_data, (u8 *)&priv->data, reg->len);
153 nft_payload_n2h(&_datamask, (u8 *)®->mask, reg->len);
154 data = (u8 *)&_data;
155 datamask = (u8 *)&_datamask;
156 } else {
157 data = (u8 *)&priv->data;
158 datamask = (u8 *)®->mask;
159 }
160
161 memcpy(key + reg->offset, data, reg->len);
162 memcpy(mask + reg->offset, datamask, reg->len);
163
164 flow->match.dissector.used_keys |= BIT(reg->key);
165 flow->match.dissector.offset[reg->key] = reg->base_offset;
166
167 if (reg->key == FLOW_DISSECTOR_KEY_META &&
168 reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) &&
169 nft_reg_load16(priv->data.data) != ARPHRD_ETHER)
170 return -EOPNOTSUPP;
171
172 nft_offload_update_dependency(ctx, &priv->data, reg->len);
173
174 return 0;
175 }
176
nft_cmp_offload(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_expr * expr)177 static int nft_cmp_offload(struct nft_offload_ctx *ctx,
178 struct nft_flow_rule *flow,
179 const struct nft_expr *expr)
180 {
181 const struct nft_cmp_expr *priv = nft_expr_priv(expr);
182
183 return __nft_cmp_offload(ctx, flow, priv);
184 }
185
186 static const struct nft_expr_ops nft_cmp_ops = {
187 .type = &nft_cmp_type,
188 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)),
189 .eval = nft_cmp_eval,
190 .init = nft_cmp_init,
191 .dump = nft_cmp_dump,
192 .reduce = NFT_REDUCE_READONLY,
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 */
nft_cmp_fast_mask(unsigned int len)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
nft_cmp_fast_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])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(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
nft_cmp_fast_offload(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_expr * expr)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
nft_cmp_fast_dump(struct sk_buff * skb,const struct nft_expr * expr)256 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr)
257 {
258 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
259 enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ;
260 struct nft_data data;
261
262 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
263 goto nla_put_failure;
264 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op)))
265 goto nla_put_failure;
266
267 data.data[0] = priv->data;
268 if (nft_data_dump(skb, NFTA_CMP_DATA, &data,
269 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0)
270 goto nla_put_failure;
271 return 0;
272
273 nla_put_failure:
274 return -1;
275 }
276
277 const struct nft_expr_ops nft_cmp_fast_ops = {
278 .type = &nft_cmp_type,
279 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)),
280 .eval = NULL, /* inlined */
281 .init = nft_cmp_fast_init,
282 .dump = nft_cmp_fast_dump,
283 .reduce = NFT_REDUCE_READONLY,
284 .offload = nft_cmp_fast_offload,
285 };
286
nft_cmp_mask(u32 bitlen)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
nft_cmp16_fast_mask(struct nft_data * data,unsigned int bitlen)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
nft_cmp16_fast_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])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(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
nft_cmp16_fast_offload(struct nft_offload_ctx * ctx,struct nft_flow_rule * flow,const struct nft_expr * expr)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
nft_cmp16_fast_dump(struct sk_buff * skb,const struct nft_expr * expr)350 static int nft_cmp16_fast_dump(struct sk_buff *skb, const struct nft_expr *expr)
351 {
352 const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr);
353 enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ;
354
355 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
356 goto nla_put_failure;
357 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op)))
358 goto nla_put_failure;
359
360 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data,
361 NFT_DATA_VALUE, priv->len) < 0)
362 goto nla_put_failure;
363 return 0;
364
365 nla_put_failure:
366 return -1;
367 }
368
369
370 const struct nft_expr_ops nft_cmp16_fast_ops = {
371 .type = &nft_cmp_type,
372 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp16_fast_expr)),
373 .eval = NULL, /* inlined */
374 .init = nft_cmp16_fast_init,
375 .dump = nft_cmp16_fast_dump,
376 .reduce = NFT_REDUCE_READONLY,
377 .offload = nft_cmp16_fast_offload,
378 };
379
380 static const struct nft_expr_ops *
nft_cmp_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])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
