libnftnl 1.2.9
bitwise.c
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
4 *
5 * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
6 */
7
8#include "internal.h"
9
10#include <stdio.h>
11#include <stdint.h>
12#include <string.h> /* for memcpy */
13#include <arpa/inet.h>
14#include <errno.h>
15#include <libmnl/libmnl.h>
16#include <linux/netfilter/nf_tables.h>
17#include <libnftnl/expr.h>
18#include <libnftnl/rule.h>
19
21 enum nft_registers sreg;
22 enum nft_registers sreg2;
23 enum nft_registers dreg;
24 enum nft_bitwise_ops op;
25 unsigned int len;
26 union nftnl_data_reg mask;
27 union nftnl_data_reg xor;
28 union nftnl_data_reg data;
29};
30
31static int
32nftnl_expr_bitwise_set(struct nftnl_expr *e, uint16_t type,
33 const void *data, uint32_t data_len)
34{
35 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
36
37 switch(type) {
38 case NFTNL_EXPR_BITWISE_SREG:
39 memcpy(&bitwise->sreg, data, data_len);
40 break;
41 case NFTNL_EXPR_BITWISE_SREG2:
42 memcpy(&bitwise->sreg2, data, sizeof(bitwise->sreg2));
43 break;
44 case NFTNL_EXPR_BITWISE_DREG:
45 memcpy(&bitwise->dreg, data, data_len);
46 break;
47 case NFTNL_EXPR_BITWISE_OP:
48 memcpy(&bitwise->op, data, data_len);
49 break;
50 case NFTNL_EXPR_BITWISE_LEN:
51 memcpy(&bitwise->len, data, data_len);
52 break;
53 case NFTNL_EXPR_BITWISE_MASK:
54 return nftnl_data_cpy(&bitwise->mask, data, data_len);
55 case NFTNL_EXPR_BITWISE_XOR:
56 return nftnl_data_cpy(&bitwise->xor, data, data_len);
57 case NFTNL_EXPR_BITWISE_DATA:
58 return nftnl_data_cpy(&bitwise->data, data, data_len);
59 }
60 return 0;
61}
62
63static const void *
64nftnl_expr_bitwise_get(const struct nftnl_expr *e, uint16_t type,
65 uint32_t *data_len)
66{
67 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
68
69 switch(type) {
70 case NFTNL_EXPR_BITWISE_SREG:
71 *data_len = sizeof(bitwise->sreg);
72 return &bitwise->sreg;
73 case NFTNL_EXPR_BITWISE_SREG2:
74 *data_len = sizeof(bitwise->sreg2);
75 return &bitwise->sreg2;
76 case NFTNL_EXPR_BITWISE_DREG:
77 *data_len = sizeof(bitwise->dreg);
78 return &bitwise->dreg;
79 case NFTNL_EXPR_BITWISE_OP:
80 *data_len = sizeof(bitwise->op);
81 return &bitwise->op;
82 case NFTNL_EXPR_BITWISE_LEN:
83 *data_len = sizeof(bitwise->len);
84 return &bitwise->len;
85 case NFTNL_EXPR_BITWISE_MASK:
86 *data_len = bitwise->mask.len;
87 return &bitwise->mask.val;
88 case NFTNL_EXPR_BITWISE_XOR:
89 *data_len = bitwise->xor.len;
90 return &bitwise->xor.val;
91 case NFTNL_EXPR_BITWISE_DATA:
92 *data_len = bitwise->data.len;
93 return &bitwise->data.val;
94 }
95 return NULL;
96}
97
98static int nftnl_expr_bitwise_cb(const struct nlattr *attr, void *data)
99{
100 const struct nlattr **tb = data;
101 int type = mnl_attr_get_type(attr);
102
103 if (mnl_attr_type_valid(attr, NFTA_BITWISE_MAX) < 0)
104 return MNL_CB_OK;
105
106 switch(type) {
107 case NFTA_BITWISE_SREG:
108 case NFTA_BITWISE_SREG2:
109 case NFTA_BITWISE_DREG:
110 case NFTA_BITWISE_OP:
111 case NFTA_BITWISE_LEN:
112 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
113 abi_breakage();
114 break;
115 case NFTA_BITWISE_MASK:
116 case NFTA_BITWISE_XOR:
117 case NFTA_BITWISE_DATA:
118 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
119 abi_breakage();
120 break;
121 }
122
123 tb[type] = attr;
124 return MNL_CB_OK;
125}
126
127static void
128nftnl_expr_bitwise_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
129{
130 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
131
132 if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG))
133 mnl_attr_put_u32(nlh, NFTA_BITWISE_SREG, htonl(bitwise->sreg));
134 if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG2))
135 mnl_attr_put_u32(nlh, NFTA_BITWISE_SREG2, htonl(bitwise->sreg2));
136 if (e->flags & (1 << NFTNL_EXPR_BITWISE_DREG))
137 mnl_attr_put_u32(nlh, NFTA_BITWISE_DREG, htonl(bitwise->dreg));
138 if (e->flags & (1 << NFTNL_EXPR_BITWISE_OP))
139 mnl_attr_put_u32(nlh, NFTA_BITWISE_OP, htonl(bitwise->op));
140 if (e->flags & (1 << NFTNL_EXPR_BITWISE_LEN))
141 mnl_attr_put_u32(nlh, NFTA_BITWISE_LEN, htonl(bitwise->len));
142 if (e->flags & (1 << NFTNL_EXPR_BITWISE_MASK)) {
143 struct nlattr *nest;
144
145 nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_MASK);
146 mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->mask.len,
147 bitwise->mask.val);
148 mnl_attr_nest_end(nlh, nest);
149 }
150 if (e->flags & (1 << NFTNL_EXPR_BITWISE_XOR)) {
151 struct nlattr *nest;
152
153 nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_XOR);
154 mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->xor.len,
155 bitwise->xor.val);
156 mnl_attr_nest_end(nlh, nest);
157 }
158 if (e->flags & (1 << NFTNL_EXPR_BITWISE_DATA)) {
159 struct nlattr *nest;
160
161 nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_DATA);
162 mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->data.len,
163 bitwise->data.val);
164 mnl_attr_nest_end(nlh, nest);
165 }
166}
167
168static int
169nftnl_expr_bitwise_parse(struct nftnl_expr *e, struct nlattr *attr)
170{
171 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
172 struct nlattr *tb[NFTA_BITWISE_MAX+1] = {};
173 int ret = 0;
174
175 if (mnl_attr_parse_nested(attr, nftnl_expr_bitwise_cb, tb) < 0)
176 return -1;
177
178 if (tb[NFTA_BITWISE_SREG]) {
179 bitwise->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_SREG]));
180 e->flags |= (1 << NFTNL_EXPR_BITWISE_SREG);
181 }
182 if (tb[NFTA_BITWISE_SREG2]) {
183 bitwise->sreg2 = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_SREG2]));
184 e->flags |= (1 << NFTNL_EXPR_BITWISE_SREG2);
185 }
186 if (tb[NFTA_BITWISE_DREG]) {
187 bitwise->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_DREG]));
188 e->flags |= (1 << NFTNL_EXPR_BITWISE_DREG);
189 }
190 if (tb[NFTA_BITWISE_OP]) {
191 bitwise->op = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_OP]));
192 e->flags |= (1 << NFTNL_EXPR_BITWISE_OP);
193 }
194 if (tb[NFTA_BITWISE_LEN]) {
195 bitwise->len = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_LEN]));
196 e->flags |= (1 << NFTNL_EXPR_BITWISE_LEN);
197 }
198 if (tb[NFTA_BITWISE_MASK]) {
199 ret = nftnl_parse_data(&bitwise->mask, tb[NFTA_BITWISE_MASK], NULL);
200 e->flags |= (1 << NFTA_BITWISE_MASK);
201 }
202 if (tb[NFTA_BITWISE_XOR]) {
203 ret = nftnl_parse_data(&bitwise->xor, tb[NFTA_BITWISE_XOR], NULL);
204 e->flags |= (1 << NFTA_BITWISE_XOR);
205 }
206 if (tb[NFTA_BITWISE_DATA]) {
207 ret = nftnl_parse_data(&bitwise->data, tb[NFTA_BITWISE_DATA], NULL);
208 e->flags |= (1 << NFTNL_EXPR_BITWISE_DATA);
209 }
210
211 return ret;
212}
213
214static int
215nftnl_expr_bitwise_snprintf_mask_xor(char *buf, size_t remain,
216 const struct nftnl_expr_bitwise *bitwise)
217{
218 int offset = 0, ret;
219
220 ret = snprintf(buf, remain, "reg %u = ( reg %u & ",
221 bitwise->dreg, bitwise->sreg);
222 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
223
224 ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->mask,
225 0, DATA_VALUE);
226 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
227
228 ret = snprintf(buf + offset, remain, ") ^ ");
229 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
230
231 ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->xor,
232 0, DATA_VALUE);
233 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
234
235 return offset;
236}
237
238static int
239nftnl_expr_bitwise_snprintf_shift(char *buf, size_t remain, const char *op,
240 const struct nftnl_expr_bitwise *bitwise)
241{ int offset = 0, ret;
242
243 ret = snprintf(buf, remain, "reg %u = ( reg %u %s ",
244 bitwise->dreg, bitwise->sreg, op);
245 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
246
247 ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->data,
248 0, DATA_VALUE);
249 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
250
251 ret = snprintf(buf + offset, remain, ") ");
252 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
253
254 return offset;
255}
256
257static int
258nftnl_expr_bitwise_snprintf_bool(char *buf, size_t remain, const char *op,
259 const struct nftnl_expr *e,
260 const struct nftnl_expr_bitwise *bitwise)
261{
262 int offset = 0, ret;
263
264 ret = snprintf(buf, remain, "reg %u = ( reg %u %s ",
265 bitwise->dreg, bitwise->sreg, op);
266 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
267
268 if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG2))
269 ret = snprintf(buf + offset, remain, "reg %u ", bitwise->sreg2);
270 else
271 ret = nftnl_data_reg_snprintf(buf + offset, remain,
272 &bitwise->data,
273 0, DATA_VALUE);
274 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
275
276 ret = snprintf(buf + offset, remain, ") ");
277 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
278
279 return offset;
280}
281
282static int
283nftnl_expr_bitwise_snprintf(char *buf, size_t size,
284 uint32_t flags, const struct nftnl_expr *e)
285{
286 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
287 int err = -1;
288
289 switch (bitwise->op) {
290 case NFT_BITWISE_MASK_XOR:
291 err = nftnl_expr_bitwise_snprintf_mask_xor(buf, size, bitwise);
292 break;
293 case NFT_BITWISE_LSHIFT:
294 err = nftnl_expr_bitwise_snprintf_shift(buf, size, "<<",
295 bitwise);
296 break;
297 case NFT_BITWISE_RSHIFT:
298 err = nftnl_expr_bitwise_snprintf_shift(buf, size, ">>",
299 bitwise);
300 break;
301 case NFT_BITWISE_AND:
302 err = nftnl_expr_bitwise_snprintf_bool(buf, size, "&", e,
303 bitwise);
304 break;
305 case NFT_BITWISE_OR:
306 err = nftnl_expr_bitwise_snprintf_bool(buf, size, "|", e,
307 bitwise);
308 break;
309 case NFT_BITWISE_XOR:
310 err = nftnl_expr_bitwise_snprintf_bool(buf, size, "^", e,
311 bitwise);
312 break;
313 }
314
315 return err;
316}
317
318static struct attr_policy bitwise_attr_policy[__NFTNL_EXPR_BITWISE_MAX] = {
319 [NFTNL_EXPR_BITWISE_SREG] = { .maxlen = sizeof(uint32_t) },
320 [NFTNL_EXPR_BITWISE_DREG] = { .maxlen = sizeof(uint32_t) },
321 [NFTNL_EXPR_BITWISE_LEN] = { .maxlen = sizeof(uint32_t) },
322 [NFTNL_EXPR_BITWISE_MASK] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
323 [NFTNL_EXPR_BITWISE_XOR] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
324 [NFTNL_EXPR_BITWISE_OP] = { .maxlen = sizeof(uint32_t) },
325 [NFTNL_EXPR_BITWISE_DATA] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
326};
327
328struct expr_ops expr_ops_bitwise = {
329 .name = "bitwise",
330 .alloc_len = sizeof(struct nftnl_expr_bitwise),
331 .nftnl_max_attr = __NFTNL_EXPR_BITWISE_MAX - 1,
332 .attr_policy = bitwise_attr_policy,
333 .set = nftnl_expr_bitwise_set,
334 .get = nftnl_expr_bitwise_get,
335 .parse = nftnl_expr_bitwise_parse,
336 .build = nftnl_expr_bitwise_build,
337 .output = nftnl_expr_bitwise_snprintf,
338};