?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
bpf: ldi,ldxi: allow for '#' prefix in numbers
[netsniff-ng.git] / bpf_parser.y
blob48a6e4cd21161c298df696ecb2426008e1addf42
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 #include <libgen.h>
20 #include <linux/filter.h>
21
22 #include "bpf.h"
23 #include "str.h"
24 #include "xmalloc.h"
25 #include "bpf_parser.tab.h"
26 #include "built_in.h"
27 #include "die.h"
28
29 int compile_filter(char *file, int verbose, int bypass, int format,
30 bool invoke_cpp);
31
32 static int curr_instr = 0;
33
34 static struct sock_filter out[BPF_MAXINSNS];
35
36 static char *labels[BPF_MAXINSNS];
37 static char *labels_jt[BPF_MAXINSNS];
38 static char *labels_jf[BPF_MAXINSNS];
39 static char *labels_k[BPF_MAXINSNS];
40
41 #define YYERROR_VERBOSE 0
42 #define YYDEBUG 0
43 #define YYENABLE_NLS 1
44 #define YYLTYPE_IS_TRIVIAL 1
45 #define ENABLE_NLS 1
46
47 extern FILE *yyin;
48 extern int yylex(void);
49 extern void yyerror(const char *);
50 extern int yylineno;
51 extern char *yytext;
52
53 static inline void check_max_instr(void)
54 {
55 if (curr_instr >= BPF_MAXINSNS)
56 panic("Exceeded maximal number of instructions!\n");
57 }
58
59 static inline void set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf, uint32_t k)
60 {
61 check_max_instr();
62
63 out[curr_instr].code = code;
64 out[curr_instr].jt = jt;
65 out[curr_instr].jf = jf;
66 out[curr_instr].k = k;
67
68 curr_instr++;
69 }
70
71 static inline void set_curr_label(char *label)
72 {
73 check_max_instr();
74
75 labels[curr_instr] = label;
76 }
77
78 #define JTL 1
79 #define JFL 2
80 #define JKL 3
81
82 static inline void set_jmp_label(char *label, int which)
83 {
84 check_max_instr();
85
86 switch (which) {
87 case JTL:
88 labels_jt[curr_instr] = label;
89 break;
90 case JFL:
91 labels_jf[curr_instr] = label;
92 break;
93 case JKL:
94 labels_k[curr_instr] = label;
95 break;
96 default:
97 bug();
98 }
99 }
100
101 static int find_intr_offset_or_panic(char *label_to_search)
102 {
103 int i, max = curr_instr, ret = -ENOENT;
104
105 bug_on(!label_to_search);
106
107 for (i = 0; i < max; ++i) {
108 if (labels[i] != NULL) {
109 /* Both are \0-terminated! */
110 if (!strcmp(label_to_search, labels[i])) {
111 ret = i;
112 break;
113 }
114 }
115 }
116
117 if (ret == -ENOENT)
118 panic("No such label!\n");
119
120 return ret;
121 }
122
123 %}
124
125 %union {
126 char *label;
127 long int number;
128 }
129
130 %token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE
131 %token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH
132 %token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI
133 %token OP_LDXI
134
135 %token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE
136 %token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF
137
138 %token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#'
139
140 %token number label
141
142 %type <number> number
143 %type <label> label
144
145 %%
146
147 prog
148 : line
149 | prog line
150 ;
151
152 line
153 : instr
154 | labelled_instr
155 ;
156
157 labelled_instr
158 : labelled instr
159 ;
160
161 instr
162 : ldb
163 | ldh
164 | ld
165 | ldi
166 | ldx
167 | ldxi
168 | st
169 | stx
170 | jmp
171 | jeq
172 | jneq
173 | jlt
174 | jle
175 | jgt
176 | jge
177 | jset
178 | add
179 | sub
180 | mul
181 | div
182 | mod
183 | neg
184 | and
185 | or
186 | xor
187 | lsh
188 | rsh
189 | ret
190 | tax
191 | txa
192 ;
193
194 labelled
195 : label ':' { set_curr_label($1); }
196 ;
197
198 ldb
199 : OP_LDB '[' 'x' '+' number ']' {
200 set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); }
201 | OP_LDB '[' number ']' {
202 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); }
203 | OP_LDB K_PROTO {
204 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
205 SKF_AD_OFF + SKF_AD_PROTOCOL); }
206 | OP_LDB K_TYPE {
207 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
208 SKF_AD_OFF + SKF_AD_PKTTYPE); }
209 | OP_LDB K_IFIDX {
210 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
211 SKF_AD_OFF + SKF_AD_IFINDEX); }
212 | OP_LDB K_NLATTR {
213 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
214 SKF_AD_OFF + SKF_AD_NLATTR); }
215 | OP_LDB K_NLATTR_NEST {
216 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
217 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
218 | OP_LDB K_MARK {
219 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
220 SKF_AD_OFF + SKF_AD_MARK); }
221 | OP_LDB K_QUEUE {
222 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
223 SKF_AD_OFF + SKF_AD_QUEUE); }
224 | OP_LDB K_HATYPE {
225 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
226 SKF_AD_OFF + SKF_AD_HATYPE); }
227 | OP_LDB K_RXHASH {
228 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
229 SKF_AD_OFF + SKF_AD_RXHASH); }
230 | OP_LDB K_CPU {
231 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
232 SKF_AD_OFF + SKF_AD_CPU); }
233 | OP_LDB K_VLANT {
234 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
235 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
236 | OP_LDB K_VLANP {
237 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
238 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
239 | OP_LDB K_POFF {
240 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
241 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
242 ;
243
244 ldh
245 : OP_LDH '[' 'x' '+' number ']' {
246 set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); }
247 | OP_LDH '[' number ']' {
248 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); }
249 | OP_LDH K_PROTO {
250 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
251 SKF_AD_OFF + SKF_AD_PROTOCOL); }
252 | OP_LDH K_TYPE {
253 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
254 SKF_AD_OFF + SKF_AD_PKTTYPE); }
255 | OP_LDH K_IFIDX {
256 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
257 SKF_AD_OFF + SKF_AD_IFINDEX); }
258 | OP_LDH K_NLATTR {
259 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
260 SKF_AD_OFF + SKF_AD_NLATTR); }
261 | OP_LDH K_NLATTR_NEST {
262 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
263 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
264 | OP_LDH K_MARK {
265 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
266 SKF_AD_OFF + SKF_AD_MARK); }
267 | OP_LDH K_QUEUE {
268 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
269 SKF_AD_OFF + SKF_AD_QUEUE); }
270 | OP_LDH K_HATYPE {
271 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
272 SKF_AD_OFF + SKF_AD_HATYPE); }
273 | OP_LDH K_RXHASH {
274 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
275 SKF_AD_OFF + SKF_AD_RXHASH); }
276 | OP_LDH K_CPU {
277 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
278 SKF_AD_OFF + SKF_AD_CPU); }
279 | OP_LDH K_VLANT {
280 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
281 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
282 | OP_LDH K_VLANP {
283 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
284 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
285 | OP_LDH K_POFF {
286 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
287 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
288 ;
289
290 ldi
291 : OP_LDI '#' number {
292 set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
293 | OP_LDI number {
294 set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $2); }
295 ;
296
297 ld
298 : OP_LD '#' number {
299 set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); }
300 | OP_LD K_PKT_LEN {
301 set_curr_instr(BPF_LD | BPF_W | BPF_LEN, 0, 0, 0); }
302 | OP_LD K_PROTO {
303 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
304 SKF_AD_OFF + SKF_AD_PROTOCOL); }
305 | OP_LD K_TYPE {
306 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
307 SKF_AD_OFF + SKF_AD_PKTTYPE); }
308 | OP_LD K_IFIDX {
309 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
310 SKF_AD_OFF + SKF_AD_IFINDEX); }
311 | OP_LD K_NLATTR {
312 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
313 SKF_AD_OFF + SKF_AD_NLATTR); }
314 | OP_LD K_NLATTR_NEST {
315 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
316 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
317 | OP_LD K_MARK {
318 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
319 SKF_AD_OFF + SKF_AD_MARK); }
320 | OP_LD K_QUEUE {
321 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
322 SKF_AD_OFF + SKF_AD_QUEUE); }
323 | OP_LD K_HATYPE {
324 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
325 SKF_AD_OFF + SKF_AD_HATYPE); }
326 | OP_LD K_RXHASH {
327 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
328 SKF_AD_OFF + SKF_AD_RXHASH); }
329 | OP_LD K_CPU {
330 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
331 SKF_AD_OFF + SKF_AD_CPU); }
332 | OP_LD K_VLANT {
333 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
334 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
335 | OP_LD K_VLANP {
336 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
337 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
338 | OP_LD K_POFF {
339 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0,
340 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
341 | OP_LD 'M' '[' number ']' {
342 set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); }
343 | OP_LD '[' 'x' '+' number ']' {
344 set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); }
345 | OP_LD '[' number ']' {
346 set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); }
347 ;
348
349 ldxi
350 : OP_LDXI '#' number {
351 set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
352 | OP_LDXI number {
353 set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $2); }
354 ;
355
356 ldx
357 : OP_LDX '#' number {
358 set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
359 | OP_LDX K_PKT_LEN {
360 set_curr_instr(BPF_LDX | BPF_W | BPF_LEN, 0, 0, 0); }
361 | OP_LDX 'M' '[' number ']' {
362 set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); }
363 | OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
364 if ($2 != 4 || $9 != 0xf) {
365 panic("ldxb offset not supported!\n");
366 } else {
367 set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
368 | OP_LDX number '*' '(' '[' number ']' '&' number ')' {
369 if ($2 != 4 || $9 != 0xf) {
370 panic("ldxb offset not supported!\n");
371 } else {
372 set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
373 ;
374
375 st
376 : OP_ST 'M' '[' number ']' {
377 set_curr_instr(BPF_ST, 0, 0, $4); }
378 ;
379
380 stx
381 : OP_STX 'M' '[' number ']' {
382 set_curr_instr(BPF_STX, 0, 0, $4); }
383 ;
384
385 jmp
386 : OP_JMP label {
387 set_jmp_label($2, JKL);
388 set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); }
389 ;
390
391 jeq
392 : OP_JEQ '#' number ',' label ',' label {
393 set_jmp_label($5, JTL);
394 set_jmp_label($7, JFL);
395 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
396 | OP_JEQ 'x' ',' label ',' label {
397 set_jmp_label($4, JTL);
398 set_jmp_label($6, JFL);
399 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
400 | OP_JEQ '#' number ',' label {
401 set_jmp_label($5, JTL);
402 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
403 | OP_JEQ 'x' ',' label {
404 set_jmp_label($4, JTL);
405 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
406 ;
407
408 jneq
409 : OP_JNEQ '#' number ',' label {
410 set_jmp_label($5, JFL);
411 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
412 | OP_JNEQ 'x' ',' label {
413 set_jmp_label($4, JFL);
414 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
415 ;
416
417 jlt
418 : OP_JLT '#' number ',' label {
419 set_jmp_label($5, JFL);
420 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
421 | OP_JLT 'x' ',' label {
422 set_jmp_label($4, JFL);
423 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
424 ;
425
426 jle
427 : OP_JLE '#' number ',' label {
428 set_jmp_label($5, JFL);
429 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
430 | OP_JLE 'x' ',' label {
431 set_jmp_label($4, JFL);
432 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
433 ;
434
435 jgt
436 : OP_JGT '#' number ',' label ',' label {
437 set_jmp_label($5, JTL);
438 set_jmp_label($7, JFL);
439 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
440 | OP_JGT 'x' ',' label ',' label {
441 set_jmp_label($4, JTL);
442 set_jmp_label($6, JFL);
443 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
444 | OP_JGT '#' number ',' label {
445 set_jmp_label($5, JTL);
446 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
447 | OP_JGT 'x' ',' label {
448 set_jmp_label($4, JTL);
449 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
450 ;
451
452 jge
453 : OP_JGE '#' number ',' label ',' label {
454 set_jmp_label($5, JTL);
455 set_jmp_label($7, JFL);
456 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
457 | OP_JGE 'x' ',' label ',' label {
458 set_jmp_label($4, JTL);
459 set_jmp_label($6, JFL);
460 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
461 | OP_JGE '#' number ',' label {
462 set_jmp_label($5, JTL);
463 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
464 | OP_JGE 'x' ',' label {
465 set_jmp_label($4, JTL);
466 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
467 ;
468
469 jset
470 : OP_JSET '#' number ',' label ',' label {
471 set_jmp_label($5, JTL);
472 set_jmp_label($7, JFL);
473 set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
474 | OP_JSET 'x' ',' label ',' label {
475 set_jmp_label($4, JTL);
476 set_jmp_label($6, JFL);
477 set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
478 | OP_JSET '#' number ',' label {
479 set_jmp_label($5, JTL);
480 set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
481 | OP_JSET 'x' ',' label {
482 set_jmp_label($4, JTL);
483 set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
484 ;
485
486 add
487 : OP_ADD '#' number {
488 set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); }
489 | OP_ADD 'x' {
490 set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
491 ;
492
493 sub
494 : OP_SUB '#' number {
495 set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); }
496 | OP_SUB 'x' {
497 set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
498 ;
499
500 mul
501 : OP_MUL '#' number {
502 set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); }
503 | OP_MUL 'x' {
504 set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
505 ;
506
507 div
508 : OP_DIV '#' number {
509 set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); }
510 | OP_DIV 'x' {
511 set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
512 ;
513
514 mod
515 : OP_MOD '#' number {
516 set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); }
517 | OP_MOD 'x' {
518 set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
519 ;
520
521 neg
522 : OP_NEG {
523 set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); }
524 ;
525
526 and
527 : OP_AND '#' number {
528 set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); }
529 | OP_AND 'x' {
530 set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
531 ;
532
533 or
534 : OP_OR '#' number {
535 set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); }
536 | OP_OR 'x' {
537 set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
538 ;
539
540 xor
541 : OP_XOR '#' number {
542 set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); }
543 | OP_XOR 'x' {
544 set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
545 ;
546
547 lsh
548 : OP_LSH '#' number {
549 set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); }
550 | OP_LSH 'x' {
551 set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
552 ;
553
554 rsh
555 : OP_RSH '#' number {
556 set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); }
557 | OP_RSH 'x' {
558 set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
559 ;
560
561 ret
562 : OP_RET 'a' {
563 set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
564 | OP_RET 'x' {
565 set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
566 | OP_RET '#' number {
567 set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); }
568 ;
569
570 tax
571 : OP_TAX {
572 set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); }
573 ;
574
575 txa
576 : OP_TXA {
577 set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); }
578 ;
579
580 %%
581
582 static void stage_1_inline(void)
583 {
584 yyparse();
585 }
586
587 static void stage_2_label_reduce(void)
588 {
589 int i, max = curr_instr, off;
590
591 /* 1. reduce k jumps */
592 for (i = 0; i < max; ++i) {
593 if (labels_k[i] != NULL) {
594 off = find_intr_offset_or_panic(labels_k[i]);
595 out[i].k = (uint32_t) (off - i - 1);
596 }
597 }
598
599 /* 1. reduce jt jumps */
600 for (i = 0; i < max; ++i) {
601 if (labels_jt[i] != NULL) {
602 off = find_intr_offset_or_panic(labels_jt[i]);
603 out[i].jt = (uint8_t) (off - i -1);
604 }
605 }
606
607 /* 1. reduce jf jumps */
608 for (i = 0; i < max; ++i) {
609 if (labels_jf[i] != NULL) {
610 off = find_intr_offset_or_panic(labels_jf[i]);
611 out[i].jf = (uint8_t) (off - i - 1);
612 }
613 }
614 }
615
616 static void pretty_printer_c(const struct sock_fprog *prog)
617 {
618 int i;
619
620 for (i = 0; i < prog->len; ++i) {
621 printf("{ 0x%x, %u, %u, 0x%08x },\n",
622 prog->filter[i].code, prog->filter[i].jt,
623 prog->filter[i].jf, prog->filter[i].k);
624 }
625 }
626
627 static void pretty_printer_xt_bpf(const struct sock_fprog *prog)
628 {
629 int i;
630
631 printf("%d,", prog->len);
632 for (i = 0; i < prog->len; ++i) {
633 printf("%u %u %u %u,",
634 prog->filter[i].code, prog->filter[i].jt,
635 prog->filter[i].jf, prog->filter[i].k);
636 }
637
638 fflush(stdout);
639 }
640
641 static void pretty_printer_tcpdump(const struct sock_fprog *prog)
642 {
643 int i;
644
645 for (i = 0; i < prog->len; ++i) {
646 printf("%u %u %u %u\n",
647 prog->filter[i].code, prog->filter[i].jt,
648 prog->filter[i].jf, prog->filter[i].k);
649 }
650 }
651
652 static void pretty_printer(const struct sock_fprog *prog, int format)
653 {
654 switch (format) {
655 case 0:
656 pretty_printer_c(prog);
657 break;
658 case 1:
659 pretty_printer_xt_bpf(prog);
660 break;
661 case 2:
662 pretty_printer_tcpdump(prog);
663 break;
664 default:
665 bug();
666 }
667 }
668
669 int compile_filter(char *file, int verbose, int bypass, int format,
670 bool invoke_cpp)
671 {
672 int i;
673 struct sock_fprog res;
674 char tmp_file[128];
675
676 memset(tmp_file, 0, sizeof(tmp_file));
677
678 if (invoke_cpp) {
679 char cmd[256], *dir, *base, *a, *b;
680
681 dir = dirname((a = xstrdup(file)));
682 base = basename((b = xstrdup(file)));
683
684 slprintf(tmp_file, sizeof(tmp_file), "%s/.tmp-%u-%s", dir, rand(), base);
685 slprintf(cmd, sizeof(cmd), "cpp -I" PREFIX_STRING
686 "/etc/netsniff-ng/ %s > %s", file, tmp_file);
687 system(cmd);
688
689 file = tmp_file;
690 xfree(a);
691 xfree(b);
692 }
693
694 if (!strncmp("-", file, strlen("-")))
695 yyin = stdin;
696 else
697 yyin = fopen(file, "r");
698 if (!yyin)
699 panic("Cannot open file!\n");
700
701 memset(out, 0, sizeof(out));
702 memset(labels, 0, sizeof(labels));
703 memset(labels_jf, 0, sizeof(labels_jf));
704 memset(labels_jt, 0, sizeof(labels_jt));
705 memset(labels_k, 0, sizeof(labels_k));
706
707 stage_1_inline();
708 stage_2_label_reduce();
709
710 res.filter = out;
711 res.len = curr_instr;
712
713 if (verbose) {
714 printf("Generated program:\n");
715 bpf_dump_all(&res);
716 }
717
718 if (!bypass) {
719 if (verbose) {
720 printf("Validating: ");
721 fflush(stdout);
722 }
723
724 if (__bpf_validate(&res) == 0) {
725 if (verbose)
726 printf("Semantic error! BPF validation failed!\n");
727 else
728 panic("Semantic error! BPF validation failed! "
729 "Try -V for debugging output!\n");
730 } else if (verbose) {
731 printf("is runnable!\n");
732 }
733 }
734
735 if (verbose)
736 printf("Result:\n");
737
738 pretty_printer(&res, format);
739
740 for (i = 0; i < res.len; ++i) {
741 free(labels[i]);
742 free(labels_jt[i]);
743 free(labels_jf[i]);
744 free(labels_k[i]);
745 }
746
747 fclose(yyin);
748 if (invoke_cpp)
749 unlink(tmp_file);
750
751 return 0;
752 }
753
754 void yyerror(const char *err)
755 {
756 panic("Syntax error at line %d: %s! %s!\n",
757 yylineno, yytext, err);
758 }
netsniff-ng toolkit, the packet sniffing beast, staging tree