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ifpps: Rename variable containing top number of CPUs
[netsniff-ng.git] / bpf_parser.y
blob7734fb39414d8830616713ca71f3a6331817e03d
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
21 #include "bpf.h"
22 #include "xmalloc.h"
23 #include "bpf_parser.tab.h"
24 #include "built_in.h"
25 #include "die.h"
26 #include "xutils.h"
27
28 #define MAX_INSTRUCTIONS 4096
29
30 int compile_filter(char *file, int verbose, int bypass, int format,
31 bool invoke_cpp);
32
33 static int curr_instr = 0;
34
35 static struct sock_filter out[MAX_INSTRUCTIONS];
36
37 static char *labels[MAX_INSTRUCTIONS];
38
39 static char *labels_jt[MAX_INSTRUCTIONS];
40 static char *labels_jf[MAX_INSTRUCTIONS];
41 static char *labels_k[MAX_INSTRUCTIONS];
42
43 #define YYERROR_VERBOSE 0
44 #define YYDEBUG 0
45 #define YYENABLE_NLS 1
46 #define YYLTYPE_IS_TRIVIAL 1
47 #define ENABLE_NLS 1
48
49 extern FILE *yyin;
50 extern int yylex(void);
51 extern void yyerror(const char *);
52 extern int yylineno;
53 extern char *yytext;
54
55 static inline void check_max_instr(void)
56 {
57 if (curr_instr >= MAX_INSTRUCTIONS)
58 panic("Exceeded maximal number of instructions!\n");
59 }
60
61 static inline void set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf, uint32_t k)
62 {
63 check_max_instr();
64
65 out[curr_instr].code = code;
66 out[curr_instr].jt = jt;
67 out[curr_instr].jf = jf;
68 out[curr_instr].k = k;
69
70 curr_instr++;
71 }
72
73 static inline void set_curr_label(char *label)
74 {
75 check_max_instr();
76
77 labels[curr_instr] = label;
78 }
79
80 #define JTL 1
81 #define JFL 2
82 #define JKL 3
83
84 static inline void set_jmp_label(char *label, int which)
85 {
86 check_max_instr();
87
88 switch (which) {
89 case JTL:
90 labels_jt[curr_instr] = label;
91 break;
92 case JFL:
93 labels_jf[curr_instr] = label;
94 break;
95 case JKL:
96 labels_k[curr_instr] = label;
97 break;
98 default:
99 bug();
100 }
101 }
102
103 static int find_intr_offset_or_panic(char *label_to_search)
104 {
105 int i, max = curr_instr, ret = -ENOENT;
106
107 bug_on(!label_to_search);
108
109 for (i = 0; i < max; ++i) {
110 if (labels[i] != NULL) {
111 /* Both are \0-terminated! */
112 if (!strcmp(label_to_search, labels[i])) {
113 ret = i;
114 break;
115 }
116 }
117 }
118
119 if (ret == -ENOENT)
120 panic("No such label!\n");
121
122 return ret;
123 }
124
125 %}
126
127 %union {
128 char *label;
129 long int number;
130 }
131
132 %token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE
133 %token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH
134 %token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI
135 %token OP_LDXI
136
137 %token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE
138 %token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF
139
140 %token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#'
141
142 %token number label
143
144 %type <number> number
145 %type <label> label
146
147 %%
148
149 prog
150 : line
151 | prog line
152 ;
153
154 line
155 : instr
156 | labelled_instr
157 ;
158
159 labelled_instr
160 : labelled instr
161 ;
162
163 instr
164 : ldb
165 | ldh
166 | ld
167 | ldi
168 | ldx
169 | ldxi
170 | st
171 | stx
172 | jmp
173 | jeq
174 | jneq
175 | jlt
176 | jle
177 | jgt
178 | jge
179 | jset
180 | add
181 | sub
182 | mul
183 | div
184 | mod
185 | neg
186 | and
187 | or
188 | xor
189 | lsh
190 | rsh
191 | ret
192 | tax
193 | txa
194 ;
195
196 labelled
197 : label ':' { set_curr_label($1); }
198 ;
199
200 ldb
201 : OP_LDB '[' 'x' '+' number ']' {
202 set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); }
203 | OP_LDB '[' number ']' {
204 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); }
205 | OP_LDB K_PROTO {
206 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
207 SKF_AD_OFF + SKF_AD_PROTOCOL); }
208 | OP_LDB K_TYPE {
209 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
210 SKF_AD_OFF + SKF_AD_PKTTYPE); }
211 | OP_LDB K_IFIDX {
212 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
213 SKF_AD_OFF + SKF_AD_IFINDEX); }
214 | OP_LDB K_NLATTR {
215 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
216 SKF_AD_OFF + SKF_AD_NLATTR); }
217 | OP_LDB K_NLATTR_NEST {
218 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
219 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
220 | OP_LDB K_MARK {
221 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
222 SKF_AD_OFF + SKF_AD_MARK); }
223 | OP_LDB K_QUEUE {
224 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
225 SKF_AD_OFF + SKF_AD_QUEUE); }
226 | OP_LDB K_HATYPE {
227 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
228 SKF_AD_OFF + SKF_AD_HATYPE); }
229 | OP_LDB K_RXHASH {
230 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
231 SKF_AD_OFF + SKF_AD_RXHASH); }
232 | OP_LDB K_CPU {
233 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
234 SKF_AD_OFF + SKF_AD_CPU); }
235 | OP_LDB K_VLANT {
236 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
237 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
238 | OP_LDB K_VLANP {
239 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
240 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
241 | OP_LDB K_POFF {
242 set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0,
243 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
244 ;
245
246 ldh
247 : OP_LDH '[' 'x' '+' number ']' {
248 set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); }
249 | OP_LDH '[' number ']' {
250 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); }
251 | OP_LDH K_PROTO {
252 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
253 SKF_AD_OFF + SKF_AD_PROTOCOL); }
254 | OP_LDH K_TYPE {
255 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
256 SKF_AD_OFF + SKF_AD_PKTTYPE); }
257 | OP_LDH K_IFIDX {
258 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
259 SKF_AD_OFF + SKF_AD_IFINDEX); }
260 | OP_LDH K_NLATTR {
261 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
262 SKF_AD_OFF + SKF_AD_NLATTR); }
263 | OP_LDH K_NLATTR_NEST {
264 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
265 SKF_AD_OFF + SKF_AD_NLATTR_NEST); }
266 | OP_LDH K_MARK {
267 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
268 SKF_AD_OFF + SKF_AD_MARK); }
269 | OP_LDH K_QUEUE {
270 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
271 SKF_AD_OFF + SKF_AD_QUEUE); }
272 | OP_LDH K_HATYPE {
273 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
274 SKF_AD_OFF + SKF_AD_HATYPE); }
275 | OP_LDH K_RXHASH {
276 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
277 SKF_AD_OFF + SKF_AD_RXHASH); }
278 | OP_LDH K_CPU {
279 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
280 SKF_AD_OFF + SKF_AD_CPU); }
281 | OP_LDH K_VLANT {
282 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
283 SKF_AD_OFF + SKF_AD_VLAN_TAG); }
284 | OP_LDH K_VLANP {
285 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
286 SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); }
287 | OP_LDH K_POFF {
288 set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0,
289 SKF_AD_OFF + SKF_AD_PAY_OFFSET); }
290 ;
291
292 ldi
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, $2); }
352 ;
353
354 ldx
355 : OP_LDX '#' number {
356 set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); }
357 | OP_LDX 'M' '[' number ']' {
358 set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); }
359 | OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
360 if ($2 != 4 || $9 != 0xf) {
361 panic("ldxb offset not supported!\n");
362 } else {
363 set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
364 | OP_LDX number '*' '(' '[' number ']' '&' number ')' {
365 if ($2 != 4 || $9 != 0xf) {
366 panic("ldxb offset not supported!\n");
367 } else {
368 set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
369 ;
370
371 st
372 : OP_ST 'M' '[' number ']' {
373 set_curr_instr(BPF_ST, 0, 0, $4); }
374 ;
375
376 stx
377 : OP_STX 'M' '[' number ']' {
378 set_curr_instr(BPF_STX, 0, 0, $4); }
379 ;
380
381 jmp
382 : OP_JMP label {
383 set_jmp_label($2, JKL);
384 set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); }
385 ;
386
387 jeq
388 : OP_JEQ '#' number ',' label ',' label {
389 set_jmp_label($5, JTL);
390 set_jmp_label($7, JFL);
391 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
392 | OP_JEQ 'x' ',' label ',' label {
393 set_jmp_label($4, JTL);
394 set_jmp_label($6, JFL);
395 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
396 | OP_JEQ '#' number ',' label {
397 set_jmp_label($5, JTL);
398 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
399 | OP_JEQ 'x' ',' label {
400 set_jmp_label($4, JTL);
401 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
402 ;
403
404 jneq
405 : OP_JNEQ '#' number ',' label {
406 set_jmp_label($5, JFL);
407 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); }
408 | OP_JNEQ 'x' ',' label {
409 set_jmp_label($4, JFL);
410 set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); }
411 ;
412
413 jlt
414 : OP_JLT '#' number ',' label {
415 set_jmp_label($5, JFL);
416 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
417 | OP_JLT 'x' ',' label {
418 set_jmp_label($4, JFL);
419 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
420 ;
421
422 jle
423 : OP_JLE '#' number ',' label {
424 set_jmp_label($5, JFL);
425 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
426 | OP_JLE 'x' ',' label {
427 set_jmp_label($4, JFL);
428 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
429 ;
430
431 jgt
432 : OP_JGT '#' number ',' label ',' label {
433 set_jmp_label($5, JTL);
434 set_jmp_label($7, JFL);
435 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
436 | OP_JGT 'x' ',' label ',' label {
437 set_jmp_label($4, JTL);
438 set_jmp_label($6, JFL);
439 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
440 | OP_JGT '#' number ',' label {
441 set_jmp_label($5, JTL);
442 set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); }
443 | OP_JGT 'x' ',' label {
444 set_jmp_label($4, JTL);
445 set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); }
446 ;
447
448 jge
449 : OP_JGE '#' number ',' label ',' label {
450 set_jmp_label($5, JTL);
451 set_jmp_label($7, JFL);
452 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
453 | OP_JGE 'x' ',' label ',' label {
454 set_jmp_label($4, JTL);
455 set_jmp_label($6, JFL);
456 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
457 | OP_JGE '#' number ',' label {
458 set_jmp_label($5, JTL);
459 set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); }
460 | OP_JGE 'x' ',' label {
461 set_jmp_label($4, JTL);
462 set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); }
463 ;
464
465 jset
466 : OP_JSET '#' number ',' label ',' label {
467 set_jmp_label($5, JTL);
468 set_jmp_label($7, JFL);
469 set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
470 | OP_JSET 'x' ',' label ',' label {
471 set_jmp_label($4, JTL);
472 set_jmp_label($6, JFL);
473 set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
474 | OP_JSET '#' number ',' label {
475 set_jmp_label($5, JTL);
476 set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); }
477 | OP_JSET 'x' ',' label {
478 set_jmp_label($4, JTL);
479 set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); }
480 ;
481
482 add
483 : OP_ADD '#' number {
484 set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); }
485 | OP_ADD 'x' {
486 set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); }
487 ;
488
489 sub
490 : OP_SUB '#' number {
491 set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); }
492 | OP_SUB 'x' {
493 set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); }
494 ;
495
496 mul
497 : OP_MUL '#' number {
498 set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); }
499 | OP_MUL 'x' {
500 set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); }
501 ;
502
503 div
504 : OP_DIV '#' number {
505 set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); }
506 | OP_DIV 'x' {
507 set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); }
508 ;
509
510 mod
511 : OP_MOD '#' number {
512 set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); }
513 | OP_MOD 'x' {
514 set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); }
515 ;
516
517 neg
518 : OP_NEG {
519 set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); }
520 ;
521
522 and
523 : OP_AND '#' number {
524 set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); }
525 | OP_AND 'x' {
526 set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); }
527 ;
528
529 or
530 : OP_OR '#' number {
531 set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); }
532 | OP_OR 'x' {
533 set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); }
534 ;
535
536 xor
537 : OP_XOR '#' number {
538 set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); }
539 | OP_XOR 'x' {
540 set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); }
541 ;
542
543 lsh
544 : OP_LSH '#' number {
545 set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); }
546 | OP_LSH 'x' {
547 set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); }
548 ;
549
550 rsh
551 : OP_RSH '#' number {
552 set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); }
553 | OP_RSH 'x' {
554 set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); }
555 ;
556
557 ret
558 : OP_RET 'a' {
559 set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); }
560 | OP_RET 'x' {
561 set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); }
562 | OP_RET '#' number {
563 set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); }
564 ;
565
566 tax
567 : OP_TAX {
568 set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); }
569 ;
570
571 txa
572 : OP_TXA {
573 set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); }
574 ;
575
576 %%
577
578 static void stage_1_inline(void)
579 {
580 yyparse();
581 }
582
583 static void stage_2_label_reduce(void)
584 {
585 int i, max = curr_instr, off;
586
587 /* 1. reduce k jumps */
588 for (i = 0; i < max; ++i) {
589 if (labels_k[i] != NULL) {
590 off = find_intr_offset_or_panic(labels_k[i]);
591 out[i].k = (uint32_t) (off - i - 1);
592 }
593 }
594
595 /* 1. reduce jt jumps */
596 for (i = 0; i < max; ++i) {
597 if (labels_jt[i] != NULL) {
598 off = find_intr_offset_or_panic(labels_jt[i]);
599 out[i].jt = (uint8_t) (off - i -1);
600 }
601 }
602
603 /* 1. reduce jf jumps */
604 for (i = 0; i < max; ++i) {
605 if (labels_jf[i] != NULL) {
606 off = find_intr_offset_or_panic(labels_jf[i]);
607 out[i].jf = (uint8_t) (off - i - 1);
608 }
609 }
610 }
611
612 static void pretty_printer_c(const struct sock_fprog *prog)
613 {
614 int i;
615
616 for (i = 0; i < prog->len; ++i) {
617 printf("{ 0x%x, %u, %u, 0x%08x },\n",
618 prog->filter[i].code, prog->filter[i].jt,
619 prog->filter[i].jf, prog->filter[i].k);
620 }
621 }
622
623 static void pretty_printer_xt_bpf(const struct sock_fprog *prog)
624 {
625 int i;
626
627 printf("%d,", prog->len);
628 for (i = 0; i < prog->len; ++i) {
629 printf("%u %u %u %u,",
630 prog->filter[i].code, prog->filter[i].jt,
631 prog->filter[i].jf, prog->filter[i].k);
632 }
633
634 fflush(stdout);
635 }
636
637 static void pretty_printer_tcpdump(const struct sock_fprog *prog)
638 {
639 int i;
640
641 for (i = 0; i < prog->len; ++i) {
642 printf("%u %u %u %u\n",
643 prog->filter[i].code, prog->filter[i].jt,
644 prog->filter[i].jf, prog->filter[i].k);
645 }
646 }
647
648 static void pretty_printer(const struct sock_fprog *prog, int format)
649 {
650 switch (format) {
651 case 0:
652 pretty_printer_c(prog);
653 break;
654 case 1:
655 pretty_printer_xt_bpf(prog);
656 break;
657 case 2:
658 pretty_printer_tcpdump(prog);
659 break;
660 default:
661 bug();
662 }
663 }
664
665 int compile_filter(char *file, int verbose, int bypass, int format,
666 bool invoke_cpp)
667 {
668 int i;
669 struct sock_fprog res;
670 char tmp_file[128];
671
672 memset(tmp_file, 0, sizeof(tmp_file));
673
674 if (invoke_cpp) {
675 char cmd[256], *dir, *base, *a, *b;
676
677 dir = dirname((a = xstrdup(file)));
678 base = basename((b = xstrdup(file)));
679
680 slprintf(tmp_file, sizeof(tmp_file), "%s/.tmp-%u-%s", dir, rand(), base);
681 slprintf(cmd, sizeof(cmd), "cpp -I" PREFIX_STRING
682 "/etc/netsniff-ng/ %s > %s", file, tmp_file);
683 system(cmd);
684
685 file = tmp_file;
686 xfree(a);
687 xfree(b);
688 }
689
690 if (!strncmp("-", file, strlen("-")))
691 yyin = stdin;
692 else
693 yyin = fopen(file, "r");
694 if (!yyin)
695 panic("Cannot open file!\n");
696
697 memset(out, 0, sizeof(out));
698 memset(labels, 0, sizeof(labels));
699 memset(labels_jf, 0, sizeof(labels_jf));
700 memset(labels_jt, 0, sizeof(labels_jt));
701 memset(labels_k, 0, sizeof(labels_k));
702
703 stage_1_inline();
704 stage_2_label_reduce();
705
706 res.filter = out;
707 res.len = curr_instr;
708
709 if (verbose) {
710 printf("Generated program:\n");
711 bpf_dump_all(&res);
712 }
713
714 if (!bypass) {
715 if (verbose) {
716 printf("Validating: ");
717 fflush(stdout);
718 }
719
720 if (__bpf_validate(&res) == 0) {
721 if (verbose)
722 printf("Semantic error! BPF validation failed!\n");
723 else
724 panic("Semantic error! BPF validation failed! "
725 "Try -V for debugging output!\n");
726 } else if (verbose) {
727 printf("is runnable!\n");
728 }
729 }
730
731 if (verbose)
732 printf("Result:\n");
733
734 pretty_printer(&res, format);
735
736 for (i = 0; i < res.len; ++i) {
737 free(labels[i]);
738 free(labels_jt[i]);
739 free(labels_jf[i]);
740 free(labels_k[i]);
741 }
742
743 fclose(yyin);
744 if (invoke_cpp)
745 unlink(tmp_file);
746
747 return 0;
748 }
749
750 void yyerror(const char *err)
751 {
752 panic("Syntax error at line %d: %s! %s!\n",
753 yylineno, yytext, err);
754 }
netsniff-ng toolkit, the packet sniffing beast, staging tree