libnftnl 1.2.8
bitwise.c
1/*
2 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published
6 * by the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
10 */
11
12#include "internal.h"
13
14#include <stdio.h>
15#include <stdint.h>
16#include <string.h> /* for memcpy */
17#include <arpa/inet.h>
18#include <errno.h>
19#include <libmnl/libmnl.h>
20#include <linux/netfilter/nf_tables.h>
21#include <libnftnl/expr.h>
22#include <libnftnl/rule.h>
23
25 enum nft_registers sreg;
26 enum nft_registers dreg;
27 enum nft_bitwise_ops op;
28 unsigned int len;
29 union nftnl_data_reg mask;
30 union nftnl_data_reg xor;
31 union nftnl_data_reg data;
32};
33
34static int
35nftnl_expr_bitwise_set(struct nftnl_expr *e, uint16_t type,
36 const void *data, uint32_t data_len)
37{
38 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
39
40 switch(type) {
41 case NFTNL_EXPR_BITWISE_SREG:
42 memcpy(&bitwise->sreg, data, data_len);
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_DREG:
74 *data_len = sizeof(bitwise->dreg);
75 return &bitwise->dreg;
76 case NFTNL_EXPR_BITWISE_OP:
77 *data_len = sizeof(bitwise->op);
78 return &bitwise->op;
79 case NFTNL_EXPR_BITWISE_LEN:
80 *data_len = sizeof(bitwise->len);
81 return &bitwise->len;
82 case NFTNL_EXPR_BITWISE_MASK:
83 *data_len = bitwise->mask.len;
84 return &bitwise->mask.val;
85 case NFTNL_EXPR_BITWISE_XOR:
86 *data_len = bitwise->xor.len;
87 return &bitwise->xor.val;
88 case NFTNL_EXPR_BITWISE_DATA:
89 *data_len = bitwise->data.len;
90 return &bitwise->data.val;
91 }
92 return NULL;
93}
94
95static int nftnl_expr_bitwise_cb(const struct nlattr *attr, void *data)
96{
97 const struct nlattr **tb = data;
98 int type = mnl_attr_get_type(attr);
99
100 if (mnl_attr_type_valid(attr, NFTA_BITWISE_MAX) < 0)
101 return MNL_CB_OK;
102
103 switch(type) {
104 case NFTA_BITWISE_SREG:
105 case NFTA_BITWISE_DREG:
106 case NFTA_BITWISE_OP:
107 case NFTA_BITWISE_LEN:
108 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
109 abi_breakage();
110 break;
111 case NFTA_BITWISE_MASK:
112 case NFTA_BITWISE_XOR:
113 case NFTA_BITWISE_DATA:
114 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
115 abi_breakage();
116 break;
117 }
118
119 tb[type] = attr;
120 return MNL_CB_OK;
121}
122
123static void
124nftnl_expr_bitwise_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
125{
126 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
127
128 if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG))
129 mnl_attr_put_u32(nlh, NFTA_BITWISE_SREG, htonl(bitwise->sreg));
130 if (e->flags & (1 << NFTNL_EXPR_BITWISE_DREG))
131 mnl_attr_put_u32(nlh, NFTA_BITWISE_DREG, htonl(bitwise->dreg));
132 if (e->flags & (1 << NFTNL_EXPR_BITWISE_OP))
133 mnl_attr_put_u32(nlh, NFTA_BITWISE_OP, htonl(bitwise->op));
134 if (e->flags & (1 << NFTNL_EXPR_BITWISE_LEN))
135 mnl_attr_put_u32(nlh, NFTA_BITWISE_LEN, htonl(bitwise->len));
136 if (e->flags & (1 << NFTNL_EXPR_BITWISE_MASK)) {
137 struct nlattr *nest;
138
139 nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_MASK);
140 mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->mask.len,
141 bitwise->mask.val);
142 mnl_attr_nest_end(nlh, nest);
143 }
144 if (e->flags & (1 << NFTNL_EXPR_BITWISE_XOR)) {
145 struct nlattr *nest;
146
147 nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_XOR);
148 mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->xor.len,
149 bitwise->xor.val);
150 mnl_attr_nest_end(nlh, nest);
151 }
152 if (e->flags & (1 << NFTNL_EXPR_BITWISE_DATA)) {
153 struct nlattr *nest;
154
155 nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_DATA);
156 mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->data.len,
157 bitwise->data.val);
158 mnl_attr_nest_end(nlh, nest);
159 }
160}
161
162static int
163nftnl_expr_bitwise_parse(struct nftnl_expr *e, struct nlattr *attr)
164{
165 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
166 struct nlattr *tb[NFTA_BITWISE_MAX+1] = {};
167 int ret = 0;
168
169 if (mnl_attr_parse_nested(attr, nftnl_expr_bitwise_cb, tb) < 0)
170 return -1;
171
172 if (tb[NFTA_BITWISE_SREG]) {
173 bitwise->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_SREG]));
174 e->flags |= (1 << NFTNL_EXPR_BITWISE_SREG);
175 }
176 if (tb[NFTA_BITWISE_DREG]) {
177 bitwise->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_DREG]));
178 e->flags |= (1 << NFTNL_EXPR_BITWISE_DREG);
179 }
180 if (tb[NFTA_BITWISE_OP]) {
181 bitwise->op = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_OP]));
182 e->flags |= (1 << NFTNL_EXPR_BITWISE_OP);
183 }
184 if (tb[NFTA_BITWISE_LEN]) {
185 bitwise->len = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_LEN]));
186 e->flags |= (1 << NFTNL_EXPR_BITWISE_LEN);
187 }
188 if (tb[NFTA_BITWISE_MASK]) {
189 ret = nftnl_parse_data(&bitwise->mask, tb[NFTA_BITWISE_MASK], NULL);
190 e->flags |= (1 << NFTA_BITWISE_MASK);
191 }
192 if (tb[NFTA_BITWISE_XOR]) {
193 ret = nftnl_parse_data(&bitwise->xor, tb[NFTA_BITWISE_XOR], NULL);
194 e->flags |= (1 << NFTA_BITWISE_XOR);
195 }
196 if (tb[NFTA_BITWISE_DATA]) {
197 ret = nftnl_parse_data(&bitwise->data, tb[NFTA_BITWISE_DATA], NULL);
198 e->flags |= (1 << NFTNL_EXPR_BITWISE_DATA);
199 }
200
201 return ret;
202}
203
204static int
205nftnl_expr_bitwise_snprintf_bool(char *buf, size_t remain,
206 const struct nftnl_expr_bitwise *bitwise)
207{
208 int offset = 0, ret;
209
210 ret = snprintf(buf, remain, "reg %u = ( reg %u & ",
211 bitwise->dreg, bitwise->sreg);
212 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
213
214 ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->mask,
215 0, DATA_VALUE);
216 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
217
218 ret = snprintf(buf + offset, remain, ") ^ ");
219 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
220
221 ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->xor,
222 0, DATA_VALUE);
223 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
224
225 return offset;
226}
227
228static int
229nftnl_expr_bitwise_snprintf_shift(char *buf, size_t remain, const char *op,
230 const struct nftnl_expr_bitwise *bitwise)
231{ int offset = 0, ret;
232
233 ret = snprintf(buf, remain, "reg %u = ( reg %u %s ",
234 bitwise->dreg, bitwise->sreg, op);
235 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
236
237 ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->data,
238 0, DATA_VALUE);
239 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
240
241 ret = snprintf(buf + offset, remain, ") ");
242 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
243
244 return offset;
245}
246
247static int
248nftnl_expr_bitwise_snprintf(char *buf, size_t size,
249 uint32_t flags, const struct nftnl_expr *e)
250{
251 struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e);
252 int err = -1;
253
254 switch (bitwise->op) {
255 case NFT_BITWISE_BOOL:
256 err = nftnl_expr_bitwise_snprintf_bool(buf, size, bitwise);
257 break;
258 case NFT_BITWISE_LSHIFT:
259 err = nftnl_expr_bitwise_snprintf_shift(buf, size, "<<", bitwise);
260 break;
261 case NFT_BITWISE_RSHIFT:
262 err = nftnl_expr_bitwise_snprintf_shift(buf, size, ">>", bitwise);
263 break;
264 }
265
266 return err;
267}
268
269static struct attr_policy bitwise_attr_policy[__NFTNL_EXPR_BITWISE_MAX] = {
270 [NFTNL_EXPR_BITWISE_SREG] = { .maxlen = sizeof(uint32_t) },
271 [NFTNL_EXPR_BITWISE_DREG] = { .maxlen = sizeof(uint32_t) },
272 [NFTNL_EXPR_BITWISE_LEN] = { .maxlen = sizeof(uint32_t) },
273 [NFTNL_EXPR_BITWISE_MASK] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
274 [NFTNL_EXPR_BITWISE_XOR] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
275 [NFTNL_EXPR_BITWISE_OP] = { .maxlen = sizeof(uint32_t) },
276 [NFTNL_EXPR_BITWISE_DATA] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
277};
278
279struct expr_ops expr_ops_bitwise = {
280 .name = "bitwise",
281 .alloc_len = sizeof(struct nftnl_expr_bitwise),
282 .nftnl_max_attr = __NFTNL_EXPR_BITWISE_MAX - 1,
283 .attr_policy = bitwise_attr_policy,
284 .set = nftnl_expr_bitwise_set,
285 .get = nftnl_expr_bitwise_get,
286 .parse = nftnl_expr_bitwise_parse,
287 .build = nftnl_expr_bitwise_build,
288 .output = nftnl_expr_bitwise_snprintf,
289};