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man: netsniff-ng: include known bug from docs
[netsniff-ng.git] / bpf_parser.y
blob459ea99fa6a183f6418c5e60c28a819a89cac5d2
1 /*
2 * netsniff-ng - the packet sniffing beast
3 * By Daniel Borkmann <daniel@netsniff-ng.org>
4 * Copyright 2011 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,
5 * Swiss federal institute of technology (ETH Zurich)
6 * Subject to the GPL, version 2.
7 */
8
9 /* yaac-func-prefix: yy */
10
11 %{
12
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <stdbool.h>
16 #include <signal.h>
17 #include <stdint.h>
18 #include <errno.h>
19
20 #include "bpf.h"
21 #include "xmalloc.h"
22 #include "bpf_parser.tab.h"
23 #include "built_in.h"
24 #include "die.h"
25
26 #define MAX_INSTRUCTIONS 4096
27
28 int compile_filter(char *file, int verbose, int bypass, int format);
29
30 static int curr_instr = 0;
31
32 static struct sock_filter out[MAX_INSTRUCTIONS];
33
34 static char *labels[MAX_INSTRUCTIONS];
35
36 static char *labels_jt[MAX_INSTRUCTIONS];
37 static char *labels_jf[MAX_INSTRUCTIONS];
38 static char *labels_k[MAX_INSTRUCTIONS];
39
40 #define YYERROR_VERBOSE 0
41 #define YYDEBUG 0
42 #define YYENABLE_NLS 1
43 #define YYLTYPE_IS_TRIVIAL 1
44 #define ENABLE_NLS 1
45
46 extern FILE *yyin;
47 extern int yylex(void);
48 extern void yyerror(const char *);
49 extern int yylineno;
50 extern char *yytext;
51
52 static inline void check_max_instr(void)
53 {
54 if (curr_instr >= MAX_INSTRUCTIONS)
55 panic("Exceeded maximal number of instructions!\n");
56 }
57
58 static inline void set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf, uint32_t k)
59 {
60 check_max_instr();
61
62 out[curr_instr].code = code;
63 out[curr_instr].jt = jt;
64 out[curr_instr].jf = jf;
65 out[curr_instr].k = k;
66
67 curr_instr++;
68 }
69
70 static inline void set_curr_label(char *label)
71 {
72 check_max_instr();
73
74 labels[curr_instr] = label;
75 }
76
77 #define JTL 1
78 #define JFL 2
79 #define JKL 3
80
81 static inline void set_jmp_label(char *label, int which)
82 {
83 check_max_instr();
84
85 switch (which) {
86 case JTL:
87 labels_jt[curr_instr] = label;
88 break;
89 case JFL:
90 labels_jf[curr_instr] = label;
91 break;
92 case JKL:
93 labels_k[curr_instr] = label;
94 break;
95 default:
96 bug();
97 }
98 }
99
100 static int find_intr_offset_or_panic(char *label_to_search)
101 {
102 int i, max = curr_instr, ret = -ENOENT;
103
104 bug_on(!label_to_search);
105
106 for (i = 0; i < max; ++i) {
107 if (labels[i] != NULL) {
108 /* Both are \0-terminated! */
109 if (!strcmp(label_to_search, labels[i])) {
110 ret = i;
111 break;
112 }
113 }
114 }
115
116 if (ret == -ENOENT)
117 panic("No such label!\n");
118
119 return ret;
120 }
121
122 %}
123
124 %union {
125 char *label;
126 long int number;
127 }
128
129 %token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE
130 %token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH
131 %token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI
132 %token OP_LDXI
133
134 %token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE
135 %token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF
136
137 %token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#'
138
139 %token number label
140
141 %type <number> number
142 %type <label> label
143
144 %%
145
146 prog
147 : line
148 | prog line
149 ;
150
151 line
152 : instr
153 | labelled_instr
154 ;
155
156 labelled_instr
157 : labelled instr
158 ;
159
160 instr
161 : ldb
162 | ldh
163 | ld
164 | ldi
165 | ldx
166 | ldxi
167 | st
168 | stx
169 | jmp
170 | jeq
171 | jneq
172 | jlt
173 | jle
174 | jgt
175 | jge
176 | jset
177 | add
178 | sub
179 | mul
180 | div
181 | mod
182 | neg
183 | and
184 | or
185 | xor
186 | lsh
187 | rsh
188 | ret
189 | tax
190 | txa
191 ;
192
193 labelled
194 : label ':' { set_curr_label($1); }
195 ;
196
197 ldb
198 : OP_LDB '[' 'x' '+' number ']' {
199 set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); }
200 | OP_LDB '[' number ']' {
201 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); }
202 | OP_LDB K_PROTO {
203 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
204 SKF_AD_OFF + SKF_AD_PROTOCOL); }
205 | OP_LDB K_TYPE {
206 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
207 SKF_AD_OFF + SKF_AD_PKTTYPE); }
208 | OP_LDB K_IFIDX {
209 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
210 SKF_AD_OFF + SKF_AD_IFINDEX); }
211 | OP_LDB K_NLATTR {
212 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
213 SKF_AD_OFF + SKF_AD_NLATTR); }
214 | OP_LDB K_NLATTR_NEST {
215 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
216 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
217 | OP_LDB K_MARK {
218 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
219 SKF_AD_OFF + SKF_AD_MARK); }
220 | OP_LDB K_QUEUE {
221 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
222 SKF_AD_OFF + SKF_AD_QUEUE); }
223 | OP_LDB K_HATYPE {
224 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
225 SKF_AD_OFF + SKF_AD_HATYPE); }
226 | OP_LDB K_RXHASH {
227 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
228 SKF_AD_OFF + SKF_AD_RXHASH); }
229 | OP_LDB K_CPU {
230 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
231 SKF_AD_OFF + SKF_AD_CPU); }
232 | OP_LDB K_VLANT {
233 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
234 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
235 | OP_LDB K_VLANP {
236 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
237 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
238 | OP_LDB K_POFF {
239 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
240 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
241 ;
242
243 ldh
244 : OP_LDH '[' 'x' '+' number ']' {
245 set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); }
246 | OP_LDH '[' number ']' {
247 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); }
248 | OP_LDH K_PROTO {
249 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
250 SKF_AD_OFF + SKF_AD_PROTOCOL); }
251 | OP_LDH K_TYPE {
252 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
253 SKF_AD_OFF + SKF_AD_PKTTYPE); }
254 | OP_LDH K_IFIDX {
255 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
256 SKF_AD_OFF + SKF_AD_IFINDEX); }
257 | OP_LDH K_NLATTR {
258 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
259 SKF_AD_OFF + SKF_AD_NLATTR); }
260 | OP_LDH K_NLATTR_NEST {
261 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
262 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
263 | OP_LDH K_MARK {
264 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
265 SKF_AD_OFF + SKF_AD_MARK); }
266 | OP_LDH K_QUEUE {
267 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
268 SKF_AD_OFF + SKF_AD_QUEUE); }
269 | OP_LDH K_HATYPE {
270 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
271 SKF_AD_OFF + SKF_AD_HATYPE); }
272 | OP_LDH K_RXHASH {
273 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
274 SKF_AD_OFF + SKF_AD_RXHASH); }
275 | OP_LDH K_CPU {
276 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
277 SKF_AD_OFF + SKF_AD_CPU); }
278 | OP_LDH K_VLANT {
279 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
280 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
281 | OP_LDH K_VLANP {
282 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
283 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
284 | OP_LDH K_POFF {
285 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
286 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
287 ;
288
289 ldi
290 : OP_LDI number {
291 set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $2); }
292 ;
293
294 ld
295 : OP_LD '#' number {
296 set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
297 | OP_LD K_PKT_LEN {
298 set_curr_instr(BPF_LD | BPF_W | BPF_LEN, 0, 0, 0); }
299 | OP_LD K_PROTO {
300 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
301 SKF_AD_OFF + SKF_AD_PROTOCOL); }
302 | OP_LD K_TYPE {
303 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
304 SKF_AD_OFF + SKF_AD_PKTTYPE); }
305 | OP_LD K_IFIDX {
306 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
307 SKF_AD_OFF + SKF_AD_IFINDEX); }
308 | OP_LD K_NLATTR {
309 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
310 SKF_AD_OFF + SKF_AD_NLATTR); }
311 | OP_LD K_NLATTR_NEST {
312 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
313 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
314 | OP_LD K_MARK {
315 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
316 SKF_AD_OFF + SKF_AD_MARK); }
317 | OP_LD K_QUEUE {
318 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
319 SKF_AD_OFF + SKF_AD_QUEUE); }
320 | OP_LD K_HATYPE {
321 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
322 SKF_AD_OFF + SKF_AD_HATYPE); }
323 | OP_LD K_RXHASH {
324 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
325 SKF_AD_OFF + SKF_AD_RXHASH); }
326 | OP_LD K_CPU {
327 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
328 SKF_AD_OFF + SKF_AD_CPU); }
329 | OP_LD K_VLANT {
330 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
331 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
332 | OP_LD K_VLANP {
333 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
334 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
335 | OP_LD K_POFF {
336 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
337 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
338 | OP_LD 'M' '[' number ']' {
339 set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); }
340 | OP_LD '[' 'x' '+' number ']' {
341 set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); }
342 | OP_LD '[' number ']' {
343 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); }
344 ;
345
346 ldxi
347 : OP_LDXI number {
348 set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $2); }
349 ;
350
351 ldx
352 : OP_LDX '#' number {
353 set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
354 | OP_LDX 'M' '[' number ']' {
355 set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); }
356 | OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
357 if ($2 != 4 || $9 != 0xf) {
358 panic("ldxb offset not supported!\n");
359 } else {
360 set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
361 | OP_LDX number '*' '(' '[' number ']' '&' number ')' {
362 if ($2 != 4 || $9 != 0xf) {
363 panic("ldxb offset not supported!\n");
364 } else {
365 set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
366 ;
367
368 st
369 : OP_ST 'M' '[' number ']' {
370 set_curr_instr(BPF_ST, 0, 0, $4); }
371 ;
372
373 stx
374 : OP_STX 'M' '[' number ']' {
375 set_curr_instr(BPF_STX, 0, 0, $4); }
376 ;
377
378 jmp
379 : OP_JMP label {
380 set_jmp_label($2, JKL);
381 set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); }
382 ;
383
384 jeq
385 : OP_JEQ '#' number ',' label ',' label {
386 set_jmp_label($5, JTL);
387 set_jmp_label($7, JFL);
388 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
389 | OP_JEQ 'x' ',' label ',' label {
390 set_jmp_label($4, JTL);
391 set_jmp_label($6, JFL);
392 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
393 | OP_JEQ '#' number ',' label {
394 set_jmp_label($5, JTL);
395 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
396 | OP_JEQ 'x' ',' label {
397 set_jmp_label($4, JTL);
398 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
399 ;
400
401 jneq
402 : OP_JNEQ '#' number ',' label {
403 set_jmp_label($5, JFL);
404 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
405 | OP_JNEQ 'x' ',' label {
406 set_jmp_label($4, JFL);
407 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
408 ;
409
410 jlt
411 : OP_JLT '#' number ',' label {
412 set_jmp_label($5, JFL);
413 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
414 | OP_JLT 'x' ',' label {
415 set_jmp_label($4, JFL);
416 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
417 ;
418
419 jle
420 : OP_JLE '#' number ',' label {
421 set_jmp_label($5, JFL);
422 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
423 | OP_JLE 'x' ',' label {
424 set_jmp_label($4, JFL);
425 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
426 ;
427
428 jgt
429 : OP_JGT '#' number ',' label ',' label {
430 set_jmp_label($5, JTL);
431 set_jmp_label($7, JFL);
432 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
433 | OP_JGT 'x' ',' label ',' label {
434 set_jmp_label($4, JTL);
435 set_jmp_label($6, JFL);
436 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
437 | OP_JGT '#' number ',' label {
438 set_jmp_label($5, JTL);
439 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
440 | OP_JGT 'x' ',' label {
441 set_jmp_label($4, JTL);
442 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
443 ;
444
445 jge
446 : OP_JGE '#' number ',' label ',' label {
447 set_jmp_label($5, JTL);
448 set_jmp_label($7, JFL);
449 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
450 | OP_JGE 'x' ',' label ',' label {
451 set_jmp_label($4, JTL);
452 set_jmp_label($6, JFL);
453 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
454 | OP_JGE '#' number ',' label {
455 set_jmp_label($5, JTL);
456 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
457 | OP_JGE 'x' ',' label {
458 set_jmp_label($4, JTL);
459 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
460 ;
461
462 jset
463 : OP_JSET '#' number ',' label ',' label {
464 set_jmp_label($5, JTL);
465 set_jmp_label($7, JFL);
466 set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
467 | OP_JSET 'x' ',' label ',' label {
468 set_jmp_label($4, JTL);
469 set_jmp_label($6, JFL);
470 set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
471 | OP_JSET '#' number ',' label {
472 set_jmp_label($5, JTL);
473 set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
474 | OP_JSET 'x' ',' label {
475 set_jmp_label($4, JTL);
476 set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
477 ;
478
479 add
480 : OP_ADD '#' number {
481 set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); }
482 | OP_ADD 'x' {
483 set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
484 ;
485
486 sub
487 : OP_SUB '#' number {
488 set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); }
489 | OP_SUB 'x' {
490 set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
491 ;
492
493 mul
494 : OP_MUL '#' number {
495 set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); }
496 | OP_MUL 'x' {
497 set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
498 ;
499
500 div
501 : OP_DIV '#' number {
502 set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); }
503 | OP_DIV 'x' {
504 set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
505 ;
506
507 mod
508 : OP_MOD '#' number {
509 set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); }
510 | OP_MOD 'x' {
511 set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
512 ;
513
514 neg
515 : OP_NEG {
516 set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); }
517 ;
518
519 and
520 : OP_AND '#' number {
521 set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); }
522 | OP_AND 'x' {
523 set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
524 ;
525
526 or
527 : OP_OR '#' number {
528 set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); }
529 | OP_OR 'x' {
530 set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
531 ;
532
533 xor
534 : OP_XOR '#' number {
535 set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); }
536 | OP_XOR 'x' {
537 set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
538 ;
539
540 lsh
541 : OP_LSH '#' number {
542 set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); }
543 | OP_LSH 'x' {
544 set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
545 ;
546
547 rsh
548 : OP_RSH '#' number {
549 set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); }
550 | OP_RSH 'x' {
551 set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
552 ;
553
554 ret
555 : OP_RET 'a' {
556 set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
557 | OP_RET 'x' {
558 set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
559 | OP_RET '#' number {
560 set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); }
561 ;
562
563 tax
564 : OP_TAX {
565 set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); }
566 ;
567
568 txa
569 : OP_TXA {
570 set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); }
571 ;
572
573 %%
574
575 static void stage_1_inline(void)
576 {
577 yyparse();
578 }
579
580 static void stage_2_label_reduce(void)
581 {
582 int i, max = curr_instr, off;
583
584 /* 1. reduce k jumps */
585 for (i = 0; i < max; ++i) {
586 if (labels_k[i] != NULL) {
587 off = find_intr_offset_or_panic(labels_k[i]);
588 out[i].k = (uint32_t) (off - i - 1);
589 }
590 }
591
592 /* 1. reduce jt jumps */
593 for (i = 0; i < max; ++i) {
594 if (labels_jt[i] != NULL) {
595 off = find_intr_offset_or_panic(labels_jt[i]);
596 out[i].jt = (uint8_t) (off - i -1);
597 }
598 }
599
600 /* 1. reduce jf jumps */
601 for (i = 0; i < max; ++i) {
602 if (labels_jf[i] != NULL) {
603 off = find_intr_offset_or_panic(labels_jf[i]);
604 out[i].jf = (uint8_t) (off - i - 1);
605 }
606 }
607 }
608
609 static void pretty_printer_c(const struct sock_fprog *prog)
610 {
611 int i;
612
613 for (i = 0; i < prog->len; ++i) {
614 printf("{ 0x%x, %u, %u, 0x%08x },\n",
615 prog->filter[i].code, prog->filter[i].jt,
616 prog->filter[i].jf, prog->filter[i].k);
617 }
618 }
619
620 static void pretty_printer_xt_bpf(const struct sock_fprog *prog)
621 {
622 int i;
623
624 printf("%d,", prog->len);
625 for (i = 0; i < prog->len; ++i) {
626 printf("%u %u %u %u,",
627 prog->filter[i].code, prog->filter[i].jt,
628 prog->filter[i].jf, prog->filter[i].k);
629 }
630
631 fflush(stdout);
632 }
633
634 static void pretty_printer_tcpdump(const struct sock_fprog *prog)
635 {
636 int i;
637
638 for (i = 0; i < prog->len; ++i) {
639 printf("%u %u %u %u\n",
640 prog->filter[i].code, prog->filter[i].jt,
641 prog->filter[i].jf, prog->filter[i].k);
642 }
643 }
644
645 static void pretty_printer(const struct sock_fprog *prog, int format)
646 {
647 switch (format) {
648 case 0:
649 pretty_printer_c(prog);
650 break;
651 case 1:
652 pretty_printer_xt_bpf(prog);
653 break;
654 case 2:
655 pretty_printer_tcpdump(prog);
656 break;
657 default:
658 bug();
659 }
660 }
661
662 int compile_filter(char *file, int verbose, int bypass, int format)
663 {
664 int i;
665 struct sock_fprog res;
666
667 if (!strncmp("-", file, strlen("-")))
668 yyin = stdin;
669 else
670 yyin = fopen(file, "r");
671 if (!yyin)
672 panic("Cannot open file!\n");
673
674 memset(out, 0, sizeof(out));
675 memset(labels, 0, sizeof(labels));
676 memset(labels_jf, 0, sizeof(labels_jf));
677 memset(labels_jt, 0, sizeof(labels_jt));
678 memset(labels_k, 0, sizeof(labels_k));
679
680 stage_1_inline();
681 stage_2_label_reduce();
682
683 res.filter = out;
684 res.len = curr_instr;
685
686 if (verbose) {
687 printf("Generated program:\n");
688 bpf_dump_all(&res);
689 }
690
691 if (!bypass) {
692 if (verbose) {
693 printf("Validating: ");
694 fflush(stdout);
695 }
696
697 if (__bpf_validate(&res) == 0) {
698 if (verbose)
699 printf("Semantic error! BPF validation failed!\n");
700 else
701 panic("Semantic error! BPF validation failed! "
702 "Try -V for debugging output!\n");
703 } else if (verbose) {
704 printf("is runnable!\n");
705 }
706 }
707
708 if (verbose)
709 printf("Result:\n");
710
711 pretty_printer(&res, format);
712
713 for (i = 0; i < res.len; ++i) {
714 free(labels[i]);
715 free(labels_jt[i]);
716 free(labels_jf[i]);
717 free(labels_k[i]);
718 }
719
720 fclose(yyin);
721 return 0;
722 }
723
724 void yyerror(const char *err)
725 {
726 panic("Syntax error at line %d: %s! %s!\n",
727 yylineno, yytext, err);
728 }
netsniff-ng toolkit, the packet sniffing beast, staging tree