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(p: ®s->data[priv->sreg], q: &priv->data, size: 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 | |
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, data: &priv->data, desc: &desc, nla: tb[NFTA_CMP_DATA]); |
83 | if (err < 0) |
84 | return err; |
85 | |
86 | err = nft_parse_register_load(attr: tb[NFTA_CMP_SREG], sreg: &priv->sreg, len: 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, attr: NFTA_CMP_SREG, reg: priv->sreg)) |
101 | goto nla_put_failure; |
102 | if (nla_put_be32(skb, attrtype: NFTA_CMP_OP, htonl(priv->op))) |
103 | goto nla_put_failure; |
104 | |
105 | if (nft_data_dump(skb, attr: NFTA_CMP_DATA, data: &priv->data, |
106 | type: NFT_DATA_VALUE, len: 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: &_data, val: (u8 *)&priv->data, len: reg->len); |
154 | nft_payload_n2h(data: &_datamask, val: (u8 *)®->mask, len: 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(sreg: priv->data.data) != ARPHRD_ETHER) |
171 | return -EOPNOTSUPP; |
172 | |
173 | nft_offload_update_dependency(ctx, data: &priv->data, len: 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 | .reduce = NFT_REDUCE_READONLY, |
194 | .offload = nft_cmp_offload, |
195 | }; |
196 | |
197 | /* Calculate the mask for the nft_cmp_fast expression. On big endian the |
198 | * mask needs to include the *upper* bytes when interpreting that data as |
199 | * something smaller than the full u32, therefore a cpu_to_le32 is done. |
200 | */ |
201 | static u32 nft_cmp_fast_mask(unsigned int len) |
202 | { |
203 | __le32 mask = cpu_to_le32(~0U >> (sizeof_field(struct nft_cmp_fast_expr, |
204 | data) * BITS_PER_BYTE - len)); |
205 | |
206 | return (__force u32)mask; |
207 | } |
208 | |
209 | static int nft_cmp_fast_init(const struct nft_ctx *ctx, |
210 | const struct nft_expr *expr, |
211 | const struct nlattr * const tb[]) |
212 | { |
213 | struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); |
214 | struct nft_data data; |
215 | struct nft_data_desc desc = { |
216 | .type = NFT_DATA_VALUE, |
217 | .size = sizeof(data), |
218 | }; |
219 | int err; |
220 | |
221 | err = nft_data_init(NULL, data: &data, desc: &desc, nla: tb[NFTA_CMP_DATA]); |
222 | if (err < 0) |
223 | return err; |
224 | |
225 | err = nft_parse_register_load(attr: tb[NFTA_CMP_SREG], sreg: &priv->sreg, len: desc.len); |
226 | if (err < 0) |
227 | return err; |
228 | |
229 | desc.len *= BITS_PER_BYTE; |
230 | |
231 | priv->mask = nft_cmp_fast_mask(len: desc.len); |
232 | priv->data = data.data[0] & priv->mask; |
233 | priv->len = desc.len; |
234 | priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; |
235 | return 0; |
236 | } |
237 | |
238 | static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx, |
239 | struct nft_flow_rule *flow, |
240 | const struct nft_expr *expr) |
241 | { |
242 | const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); |
243 | struct nft_cmp_expr cmp = { |
244 | .data = { |
245 | .data = { |
246 | [0] = priv->data, |
247 | }, |
248 | }, |
249 | .sreg = priv->sreg, |
250 | .len = priv->len / BITS_PER_BYTE, |
251 | .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, |
252 | }; |
253 | |
254 | return __nft_cmp_offload(ctx, flow, priv: &cmp); |
255 | } |
256 | |
257 | static int nft_cmp_fast_dump(struct sk_buff *skb, |
258 | const struct nft_expr *expr, bool reset) |
259 | { |
260 | const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); |
261 | enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; |
262 | struct nft_data data; |
263 | |
264 | if (nft_dump_register(skb, attr: NFTA_CMP_SREG, reg: priv->sreg)) |
265 | goto nla_put_failure; |
266 | if (nla_put_be32(skb, attrtype: NFTA_CMP_OP, htonl(op))) |
267 | goto nla_put_failure; |
268 | |
269 | data.data[0] = priv->data; |
270 | if (nft_data_dump(skb, attr: NFTA_CMP_DATA, data: &data, |
271 | type: NFT_DATA_VALUE, len: priv->len / BITS_PER_BYTE) < 0) |
272 | goto nla_put_failure; |
273 | return 0; |
274 | |
275 | nla_put_failure: |
276 | return -1; |
277 | } |
278 | |
279 | const struct nft_expr_ops nft_cmp_fast_ops = { |
280 | .type = &nft_cmp_type, |
281 | .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), |
282 | .eval = NULL, /* inlined */ |
283 | .init = nft_cmp_fast_init, |
284 | .dump = nft_cmp_fast_dump, |
285 | .reduce = NFT_REDUCE_READONLY, |
286 | .offload = nft_cmp_fast_offload, |
287 | }; |
288 | |
289 | static u32 nft_cmp_mask(u32 bitlen) |
290 | { |
291 | return (__force u32)cpu_to_le32(~0U >> (sizeof(u32) * BITS_PER_BYTE - bitlen)); |
292 | } |
293 | |
294 | static void nft_cmp16_fast_mask(struct nft_data *data, unsigned int bitlen) |
295 | { |
296 | int len = bitlen / BITS_PER_BYTE; |
297 | int i, words = len / sizeof(u32); |
298 | |
299 | for (i = 0; i < words; i++) { |
300 | data->data[i] = 0xffffffff; |
301 | bitlen -= sizeof(u32) * BITS_PER_BYTE; |
302 | } |
303 | |
304 | if (len % sizeof(u32)) |
305 | data->data[i++] = nft_cmp_mask(bitlen); |
306 | |
307 | for (; i < 4; i++) |
308 | data->data[i] = 0; |
309 | } |
310 | |
311 | static int nft_cmp16_fast_init(const struct nft_ctx *ctx, |
312 | const struct nft_expr *expr, |
313 | const struct nlattr * const tb[]) |
314 | { |
315 | struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); |
316 | struct nft_data_desc desc = { |
317 | .type = NFT_DATA_VALUE, |
318 | .size = sizeof(priv->data), |
319 | }; |
320 | int err; |
321 | |
322 | err = nft_data_init(NULL, data: &priv->data, desc: &desc, nla: tb[NFTA_CMP_DATA]); |
323 | if (err < 0) |
324 | return err; |
325 | |
326 | err = nft_parse_register_load(attr: tb[NFTA_CMP_SREG], sreg: &priv->sreg, len: desc.len); |
327 | if (err < 0) |
328 | return err; |
329 | |
330 | nft_cmp16_fast_mask(data: &priv->mask, bitlen: desc.len * BITS_PER_BYTE); |
331 | priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; |
332 | priv->len = desc.len; |
333 | |
334 | return 0; |
335 | } |
336 | |
337 | static int nft_cmp16_fast_offload(struct nft_offload_ctx *ctx, |
338 | struct nft_flow_rule *flow, |
339 | const struct nft_expr *expr) |
340 | { |
341 | const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); |
342 | struct nft_cmp_expr cmp = { |
343 | .data = priv->data, |
344 | .sreg = priv->sreg, |
345 | .len = priv->len, |
346 | .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, |
347 | }; |
348 | |
349 | return __nft_cmp_offload(ctx, flow, priv: &cmp); |
350 | } |
351 | |
352 | static int nft_cmp16_fast_dump(struct sk_buff *skb, |
353 | const struct nft_expr *expr, bool reset) |
354 | { |
355 | const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); |
356 | enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; |
357 | |
358 | if (nft_dump_register(skb, attr: NFTA_CMP_SREG, reg: priv->sreg)) |
359 | goto nla_put_failure; |
360 | if (nla_put_be32(skb, attrtype: NFTA_CMP_OP, htonl(op))) |
361 | goto nla_put_failure; |
362 | |
363 | if (nft_data_dump(skb, attr: NFTA_CMP_DATA, data: &priv->data, |
364 | type: NFT_DATA_VALUE, len: priv->len) < 0) |
365 | goto nla_put_failure; |
366 | return 0; |
367 | |
368 | nla_put_failure: |
369 | return -1; |
370 | } |
371 | |
372 | |
373 | const struct nft_expr_ops nft_cmp16_fast_ops = { |
374 | .type = &nft_cmp_type, |
375 | .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp16_fast_expr)), |
376 | .eval = NULL, /* inlined */ |
377 | .init = nft_cmp16_fast_init, |
378 | .dump = nft_cmp16_fast_dump, |
379 | .reduce = NFT_REDUCE_READONLY, |
380 | .offload = nft_cmp16_fast_offload, |
381 | }; |
382 | |
383 | static const struct nft_expr_ops * |
384 | nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) |
385 | { |
386 | struct nft_data data; |
387 | struct nft_data_desc desc = { |
388 | .type = NFT_DATA_VALUE, |
389 | .size = sizeof(data), |
390 | }; |
391 | enum nft_cmp_ops op; |
392 | u8 sreg; |
393 | int err; |
394 | |
395 | if (tb[NFTA_CMP_SREG] == NULL || |
396 | tb[NFTA_CMP_OP] == NULL || |
397 | tb[NFTA_CMP_DATA] == NULL) |
398 | return ERR_PTR(error: -EINVAL); |
399 | |
400 | op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); |
401 | switch (op) { |
402 | case NFT_CMP_EQ: |
403 | case NFT_CMP_NEQ: |
404 | case NFT_CMP_LT: |
405 | case NFT_CMP_LTE: |
406 | case NFT_CMP_GT: |
407 | case NFT_CMP_GTE: |
408 | break; |
409 | default: |
410 | return ERR_PTR(error: -EINVAL); |
411 | } |
412 | |
413 | err = nft_data_init(NULL, data: &data, desc: &desc, nla: tb[NFTA_CMP_DATA]); |
414 | if (err < 0) |
415 | return ERR_PTR(error: err); |
416 | |
417 | sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG])); |
418 | |
419 | if (op == NFT_CMP_EQ || op == NFT_CMP_NEQ) { |
420 | if (desc.len <= sizeof(u32)) |
421 | return &nft_cmp_fast_ops; |
422 | else if (desc.len <= sizeof(data) && |
423 | ((sreg >= NFT_REG_1 && sreg <= NFT_REG_4) || |
424 | (sreg >= NFT_REG32_00 && sreg <= NFT_REG32_12 && sreg % 2 == 0))) |
425 | return &nft_cmp16_fast_ops; |
426 | } |
427 | return &nft_cmp_ops; |
428 | } |
429 | |
430 | struct nft_expr_type nft_cmp_type __read_mostly = { |
431 | .name = "cmp" , |
432 | .select_ops = nft_cmp_select_ops, |
433 | .policy = nft_cmp_policy, |
434 | .maxattr = NFTA_CMP_MAX, |
435 | .owner = THIS_MODULE, |
436 | }; |
437 | |