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1/*
2 * BPF asm code parser
3 *
4 * This program is free software; you can distribute 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,
7 * or (at your option) any later version.
8 *
9 * Syntax kept close to:
10 *
11 * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new
12 * architecture for user-level packet capture. In Proceedings of the
13 * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993
14 * Conference Proceedings (USENIX'93). USENIX Association, Berkeley,
15 * CA, USA, 2-2.
16 *
17 * Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
18 * Licensed under the GNU General Public License, version 2.0 (GPLv2)
19 */
20
21%{
22
23#include <stdio.h>
24#include <string.h>
25#include <stdint.h>
26#include <stdlib.h>
27#include <stdbool.h>
28#include <unistd.h>
29#include <errno.h>
30#include <assert.h>
31#include <linux/filter.h>
32
33#include "bpf_exp.yacc.h"
34
35enum jmp_type { JTL, JFL, JKL };
36
37extern FILE *yyin;
38extern int yylex(void);
39extern void yyerror(const char *str);
40
41extern void bpf_asm_compile(FILE *fp, bool cstyle);
42static void bpf_set_curr_instr(uint16_t op, uint8_t jt, uint8_t jf, uint32_t k);
43static void bpf_set_curr_label(char *label);
44static void bpf_set_jmp_label(char *label, enum jmp_type type);
45
46%}
47
48%union {
49 char *label;
50 uint32_t number;
51}
52
53%token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE
54%token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH
55%token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI
56%token OP_LDXI
57
58%token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE
59%token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF
60
61%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%'
62
63%token number label
64
65%type <label> label
66%type <number> number
67
68%%
69
70prog
71 : line
72 | prog line
73 ;
74
75line
76 : instr
77 | labelled_instr
78 ;
79
80labelled_instr
81 : labelled instr
82 ;
83
84instr
85 : ldb
86 | ldh
87 | ld
88 | ldi
89 | ldx
90 | ldxi
91 | st
92 | stx
93 | jmp
94 | jeq
95 | jneq
96 | jlt
97 | jle
98 | jgt
99 | jge
100 | jset
101 | add
102 | sub
103 | mul
104 | div
105 | mod
106 | neg
107 | and
108 | or
109 | xor
110 | lsh
111 | rsh
112 | ret
113 | tax
114 | txa
115 ;
116
117labelled
118 : label ':' { bpf_set_curr_label($1); }
119 ;
120
121ldb
122 : OP_LDB '[' 'x' '+' number ']' {
123 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); }
124 | OP_LDB '[' '%' 'x' '+' number ']' {
125 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $6); }
126 | OP_LDB '[' number ']' {
127 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); }
128 | OP_LDB K_PROTO {
129 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
130 SKF_AD_OFF + SKF_AD_PROTOCOL); }
131 | OP_LDB K_TYPE {
132 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
133 SKF_AD_OFF + SKF_AD_PKTTYPE); }
134 | OP_LDB K_IFIDX {
135 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
136 SKF_AD_OFF + SKF_AD_IFINDEX); }
137 | OP_LDB K_NLATTR {
138 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
139 SKF_AD_OFF + SKF_AD_NLATTR); }
140 | OP_LDB K_NLATTR_NEST {
141 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
142 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
143 | OP_LDB K_MARK {
144 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
145 SKF_AD_OFF + SKF_AD_MARK); }
146 | OP_LDB K_QUEUE {
147 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
148 SKF_AD_OFF + SKF_AD_QUEUE); }
149 | OP_LDB K_HATYPE {
150 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
151 SKF_AD_OFF + SKF_AD_HATYPE); }
152 | OP_LDB K_RXHASH {
153 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
154 SKF_AD_OFF + SKF_AD_RXHASH); }
155 | OP_LDB K_CPU {
156 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
157 SKF_AD_OFF + SKF_AD_CPU); }
158 | OP_LDB K_VLANT {
159 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
160 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
161 | OP_LDB K_VLANP {
162 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
163 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
164 | OP_LDB K_POFF {
165 bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
166 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
167 ;
168
169ldh
170 : OP_LDH '[' 'x' '+' number ']' {
171 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); }
172 | OP_LDH '[' '%' 'x' '+' number ']' {
173 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $6); }
174 | OP_LDH '[' number ']' {
175 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); }
176 | OP_LDH K_PROTO {
177 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
178 SKF_AD_OFF + SKF_AD_PROTOCOL); }
179 | OP_LDH K_TYPE {
180 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
181 SKF_AD_OFF + SKF_AD_PKTTYPE); }
182 | OP_LDH K_IFIDX {
183 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
184 SKF_AD_OFF + SKF_AD_IFINDEX); }
185 | OP_LDH K_NLATTR {
186 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
187 SKF_AD_OFF + SKF_AD_NLATTR); }
188 | OP_LDH K_NLATTR_NEST {
189 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
190 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
191 | OP_LDH K_MARK {
192 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
193 SKF_AD_OFF + SKF_AD_MARK); }
194 | OP_LDH K_QUEUE {
195 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
196 SKF_AD_OFF + SKF_AD_QUEUE); }
197 | OP_LDH K_HATYPE {
198 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
199 SKF_AD_OFF + SKF_AD_HATYPE); }
200 | OP_LDH K_RXHASH {
201 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
202 SKF_AD_OFF + SKF_AD_RXHASH); }
203 | OP_LDH K_CPU {
204 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
205 SKF_AD_OFF + SKF_AD_CPU); }
206 | OP_LDH K_VLANT {
207 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
208 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
209 | OP_LDH K_VLANP {
210 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
211 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
212 | OP_LDH K_POFF {
213 bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
214 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
215 ;
216
217ldi
218 : OP_LDI '#' number {
219 bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
220 | OP_LDI number {
221 bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $2); }
222 ;
223
224ld
225 : OP_LD '#' number {
226 bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
227 | OP_LD K_PKT_LEN {
228 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_LEN, 0, 0, 0); }
229 | OP_LD K_PROTO {
230 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
231 SKF_AD_OFF + SKF_AD_PROTOCOL); }
232 | OP_LD K_TYPE {
233 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
234 SKF_AD_OFF + SKF_AD_PKTTYPE); }
235 | OP_LD K_IFIDX {
236 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
237 SKF_AD_OFF + SKF_AD_IFINDEX); }
238 | OP_LD K_NLATTR {
239 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
240 SKF_AD_OFF + SKF_AD_NLATTR); }
241 | OP_LD K_NLATTR_NEST {
242 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
243 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
244 | OP_LD K_MARK {
245 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
246 SKF_AD_OFF + SKF_AD_MARK); }
247 | OP_LD K_QUEUE {
248 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
249 SKF_AD_OFF + SKF_AD_QUEUE); }
250 | OP_LD K_HATYPE {
251 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
252 SKF_AD_OFF + SKF_AD_HATYPE); }
253 | OP_LD K_RXHASH {
254 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
255 SKF_AD_OFF + SKF_AD_RXHASH); }
256 | OP_LD K_CPU {
257 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
258 SKF_AD_OFF + SKF_AD_CPU); }
259 | OP_LD K_VLANT {
260 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
261 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
262 | OP_LD K_VLANP {
263 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
264 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
265 | OP_LD K_POFF {
266 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
267 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
268 | OP_LD 'M' '[' number ']' {
269 bpf_set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); }
270 | OP_LD '[' 'x' '+' number ']' {
271 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); }
272 | OP_LD '[' '%' 'x' '+' number ']' {
273 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $6); }
274 | OP_LD '[' number ']' {
275 bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); }
276 ;
277
278ldxi
279 : OP_LDXI '#' number {
280 bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
281 | OP_LDXI number {
282 bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $2); }
283 ;
284
285ldx
286 : OP_LDX '#' number {
287 bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
288 | OP_LDX K_PKT_LEN {
289 bpf_set_curr_instr(BPF_LDX | BPF_W | BPF_LEN, 0, 0, 0); }
290 | OP_LDX 'M' '[' number ']' {
291 bpf_set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); }
292 | OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
293 if ($2 != 4 || $9 != 0xf) {
294 fprintf(stderr, "ldxb offset not supported!\n");
295 exit(0);
296 } else {
297 bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
298 | OP_LDX number '*' '(' '[' number ']' '&' number ')' {
299 if ($2 != 4 || $9 != 0xf) {
300 fprintf(stderr, "ldxb offset not supported!\n");
301 exit(0);
302 } else {
303 bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
304 ;
305
306st
307 : OP_ST 'M' '[' number ']' {
308 bpf_set_curr_instr(BPF_ST, 0, 0, $4); }
309 ;
310
311stx
312 : OP_STX 'M' '[' number ']' {
313 bpf_set_curr_instr(BPF_STX, 0, 0, $4); }
314 ;
315
316jmp
317 : OP_JMP label {
318 bpf_set_jmp_label($2, JKL);
319 bpf_set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); }
320 ;
321
322jeq
323 : OP_JEQ '#' number ',' label ',' label {
324 bpf_set_jmp_label($5, JTL);
325 bpf_set_jmp_label($7, JFL);
326 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
327 | OP_JEQ 'x' ',' label ',' label {
328 bpf_set_jmp_label($4, JTL);
329 bpf_set_jmp_label($6, JFL);
330 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
331 | OP_JEQ '%' 'x' ',' label ',' label {
332 bpf_set_jmp_label($5, JTL);
333 bpf_set_jmp_label($7, JFL);
334 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
335 | OP_JEQ '#' number ',' label {
336 bpf_set_jmp_label($5, JTL);
337 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
338 | OP_JEQ 'x' ',' label {
339 bpf_set_jmp_label($4, JTL);
340 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
341 | OP_JEQ '%' 'x' ',' label {
342 bpf_set_jmp_label($5, JTL);
343 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
344 ;
345
346jneq
347 : OP_JNEQ '#' number ',' label {
348 bpf_set_jmp_label($5, JFL);
349 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
350 | OP_JNEQ 'x' ',' label {
351 bpf_set_jmp_label($4, JFL);
352 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
353 | OP_JNEQ '%' 'x' ',' label {
354 bpf_set_jmp_label($5, JFL);
355 bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
356 ;
357
358jlt
359 : OP_JLT '#' number ',' label {
360 bpf_set_jmp_label($5, JFL);
361 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
362 | OP_JLT 'x' ',' label {
363 bpf_set_jmp_label($4, JFL);
364 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
365 | OP_JLT '%' 'x' ',' label {
366 bpf_set_jmp_label($5, JFL);
367 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
368 ;
369
370jle
371 : OP_JLE '#' number ',' label {
372 bpf_set_jmp_label($5, JFL);
373 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
374 | OP_JLE 'x' ',' label {
375 bpf_set_jmp_label($4, JFL);
376 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
377 | OP_JLE '%' 'x' ',' label {
378 bpf_set_jmp_label($5, JFL);
379 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
380 ;
381
382jgt
383 : OP_JGT '#' number ',' label ',' label {
384 bpf_set_jmp_label($5, JTL);
385 bpf_set_jmp_label($7, JFL);
386 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
387 | OP_JGT 'x' ',' label ',' label {
388 bpf_set_jmp_label($4, JTL);
389 bpf_set_jmp_label($6, JFL);
390 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
391 | OP_JGT '%' 'x' ',' label ',' label {
392 bpf_set_jmp_label($5, JTL);
393 bpf_set_jmp_label($7, JFL);
394 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
395 | OP_JGT '#' number ',' label {
396 bpf_set_jmp_label($5, JTL);
397 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
398 | OP_JGT 'x' ',' label {
399 bpf_set_jmp_label($4, JTL);
400 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
401 | OP_JGT '%' 'x' ',' label {
402 bpf_set_jmp_label($5, JTL);
403 bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
404 ;
405
406jge
407 : OP_JGE '#' number ',' label ',' label {
408 bpf_set_jmp_label($5, JTL);
409 bpf_set_jmp_label($7, JFL);
410 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
411 | OP_JGE 'x' ',' label ',' label {
412 bpf_set_jmp_label($4, JTL);
413 bpf_set_jmp_label($6, JFL);
414 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
415 | OP_JGE '%' 'x' ',' label ',' label {
416 bpf_set_jmp_label($5, JTL);
417 bpf_set_jmp_label($7, JFL);
418 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
419 | OP_JGE '#' number ',' label {
420 bpf_set_jmp_label($5, JTL);
421 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
422 | OP_JGE 'x' ',' label {
423 bpf_set_jmp_label($4, JTL);
424 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
425 | OP_JGE '%' 'x' ',' label {
426 bpf_set_jmp_label($5, JTL);
427 bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
428 ;
429
430jset
431 : OP_JSET '#' number ',' label ',' label {
432 bpf_set_jmp_label($5, JTL);
433 bpf_set_jmp_label($7, JFL);
434 bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
435 | OP_JSET 'x' ',' label ',' label {
436 bpf_set_jmp_label($4, JTL);
437 bpf_set_jmp_label($6, JFL);
438 bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
439 | OP_JSET '%' 'x' ',' label ',' label {
440 bpf_set_jmp_label($5, JTL);
441 bpf_set_jmp_label($7, JFL);
442 bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
443 | OP_JSET '#' number ',' label {
444 bpf_set_jmp_label($5, JTL);
445 bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
446 | OP_JSET 'x' ',' label {
447 bpf_set_jmp_label($4, JTL);
448 bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
449 | OP_JSET '%' 'x' ',' label {
450 bpf_set_jmp_label($5, JTL);
451 bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
452 ;
453
454add
455 : OP_ADD '#' number {
456 bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); }
457 | OP_ADD 'x' {
458 bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
459 | OP_ADD '%' 'x' {
460 bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
461 ;
462
463sub
464 : OP_SUB '#' number {
465 bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); }
466 | OP_SUB 'x' {
467 bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
468 | OP_SUB '%' 'x' {
469 bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
470 ;
471
472mul
473 : OP_MUL '#' number {
474 bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); }
475 | OP_MUL 'x' {
476 bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
477 | OP_MUL '%' 'x' {
478 bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
479 ;
480
481div
482 : OP_DIV '#' number {
483 bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); }
484 | OP_DIV 'x' {
485 bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
486 | OP_DIV '%' 'x' {
487 bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
488 ;
489
490mod
491 : OP_MOD '#' number {
492 bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); }
493 | OP_MOD 'x' {
494 bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
495 | OP_MOD '%' 'x' {
496 bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
497 ;
498
499neg
500 : OP_NEG {
501 bpf_set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); }
502 ;
503
504and
505 : OP_AND '#' number {
506 bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); }
507 | OP_AND 'x' {
508 bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
509 | OP_AND '%' 'x' {
510 bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
511 ;
512
513or
514 : OP_OR '#' number {
515 bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); }
516 | OP_OR 'x' {
517 bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
518 | OP_OR '%' 'x' {
519 bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
520 ;
521
522xor
523 : OP_XOR '#' number {
524 bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); }
525 | OP_XOR 'x' {
526 bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
527 | OP_XOR '%' 'x' {
528 bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
529 ;
530
531lsh
532 : OP_LSH '#' number {
533 bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); }
534 | OP_LSH 'x' {
535 bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
536 | OP_LSH '%' 'x' {
537 bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
538 ;
539
540rsh
541 : OP_RSH '#' number {
542 bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); }
543 | OP_RSH 'x' {
544 bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
545 | OP_RSH '%' 'x' {
546 bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
547 ;
548
549ret
550 : OP_RET 'a' {
551 bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
552 | OP_RET '%' 'a' {
553 bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
554 | OP_RET 'x' {
555 bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
556 | OP_RET '%' 'x' {
557 bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
558 | OP_RET '#' number {
559 bpf_set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); }
560 ;
561
562tax
563 : OP_TAX {
564 bpf_set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); }
565 ;
566
567txa
568 : OP_TXA {
569 bpf_set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); }
570 ;
571
572%%
573
574static int curr_instr = 0;
575static struct sock_filter out[BPF_MAXINSNS];
576static char **labels, **labels_jt, **labels_jf, **labels_k;
577
578static void bpf_assert_max(void)
579{
580 if (curr_instr >= BPF_MAXINSNS) {
581 fprintf(stderr, "only max %u insns allowed!\n", BPF_MAXINSNS);
582 exit(0);
583 }
584}
585
586static void bpf_set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf,
587 uint32_t k)
588{
589 bpf_assert_max();
590 out[curr_instr].code = code;
591 out[curr_instr].jt = jt;
592 out[curr_instr].jf = jf;
593 out[curr_instr].k = k;
594 curr_instr++;
595}
596
597static void bpf_set_curr_label(char *label)
598{
599 bpf_assert_max();
600 labels[curr_instr] = label;
601}
602
603static void bpf_set_jmp_label(char *label, enum jmp_type type)
604{
605 bpf_assert_max();
606 switch (type) {
607 case JTL:
608 labels_jt[curr_instr] = label;
609 break;
610 case JFL:
611 labels_jf[curr_instr] = label;
612 break;
613 case JKL:
614 labels_k[curr_instr] = label;
615 break;
616 }
617}
618
619static int bpf_find_insns_offset(const char *label)
620{
621 int i, max = curr_instr, ret = -ENOENT;
622
623 for (i = 0; i < max; i++) {
624 if (labels[i] && !strcmp(label, labels[i])) {
625 ret = i;
626 break;
627 }
628 }
629
630 if (ret == -ENOENT) {
631 fprintf(stderr, "no such label \'%s\'!\n", label);
632 exit(0);
633 }
634
635 return ret;
636}
637
638static void bpf_stage_1_insert_insns(void)
639{
640 yyparse();
641}
642
643static void bpf_reduce_k_jumps(void)
644{
645 int i;
646
647 for (i = 0; i < curr_instr; i++) {
648 if (labels_k[i]) {
649 int off = bpf_find_insns_offset(labels_k[i]);
650 out[i].k = (uint32_t) (off - i - 1);
651 }
652 }
653}
654
655static void bpf_reduce_jt_jumps(void)
656{
657 int i;
658
659 for (i = 0; i < curr_instr; i++) {
660 if (labels_jt[i]) {
661 int off = bpf_find_insns_offset(labels_jt[i]);
662 out[i].jt = (uint8_t) (off - i -1);
663 }
664 }
665}
666
667static void bpf_reduce_jf_jumps(void)
668{
669 int i;
670
671 for (i = 0; i < curr_instr; i++) {
672 if (labels_jf[i]) {
673 int off = bpf_find_insns_offset(labels_jf[i]);
674 out[i].jf = (uint8_t) (off - i - 1);
675 }
676 }
677}
678
679static void bpf_stage_2_reduce_labels(void)
680{
681 bpf_reduce_k_jumps();
682 bpf_reduce_jt_jumps();
683 bpf_reduce_jf_jumps();
684}
685
686static void bpf_pretty_print_c(void)
687{
688 int i;
689
690 for (i = 0; i < curr_instr; i++)
691 printf("{ %#04x, %2u, %2u, %#010x },\n", out[i].code,
692 out[i].jt, out[i].jf, out[i].k);
693}
694
695static void bpf_pretty_print(void)
696{
697 int i;
698
699 printf("%u,", curr_instr);
700 for (i = 0; i < curr_instr; i++)
701 printf("%u %u %u %u,", out[i].code,
702 out[i].jt, out[i].jf, out[i].k);
703 printf("\n");
704}
705
706static void bpf_init(void)
707{
708 memset(out, 0, sizeof(out));
709
710 labels = calloc(BPF_MAXINSNS, sizeof(*labels));
711 assert(labels);
712 labels_jt = calloc(BPF_MAXINSNS, sizeof(*labels_jt));
713 assert(labels_jt);
714 labels_jf = calloc(BPF_MAXINSNS, sizeof(*labels_jf));
715 assert(labels_jf);
716 labels_k = calloc(BPF_MAXINSNS, sizeof(*labels_k));
717 assert(labels_k);
718}
719
720static void bpf_destroy_labels(void)
721{
722 int i;
723
724 for (i = 0; i < curr_instr; i++) {
725 free(labels_jf[i]);
726 free(labels_jt[i]);
727 free(labels_k[i]);
728 free(labels[i]);
729 }
730}
731
732static void bpf_destroy(void)
733{
734 bpf_destroy_labels();
735 free(labels_jt);
736 free(labels_jf);
737 free(labels_k);
738 free(labels);
739}
740
741void bpf_asm_compile(FILE *fp, bool cstyle)
742{
743 yyin = fp;
744
745 bpf_init();
746 bpf_stage_1_insert_insns();
747 bpf_stage_2_reduce_labels();
748 bpf_destroy();
749
750 if (cstyle)
751 bpf_pretty_print_c();
752 else
753 bpf_pretty_print();
754
755 if (fp != stdin)
756 fclose(yyin);
757}
758
759void yyerror(const char *str)
760{
761 exit(1);
762}