aboutsummaryrefslogtreecommitdiffstats
path: root/tools
diff options
context:
space:
mode:
authorDaniel Borkmann <dborkman@redhat.com>2013-12-11 17:43:44 -0500
committerDavid S. Miller <davem@davemloft.net>2013-12-11 20:28:35 -0500
commit3f356385e8a449e1d7cfc6b6f8d634ac4f5581a0 (patch)
tree6f330ea61260191ce50d539f0b95f3c3b26d0a00 /tools
parentfd981e3c321a7e8661e06fa6077aea89e8228c3a (diff)
filter: bpf_asm: add minimal bpf asm tool
There are a couple of valid use cases for a minimal low-level bpf asm like tool, for example, using/linking to libpcap is not an option, the required BPF filters use Linux extensions that are not supported by libpcap's compiler, a filter might be more complex and not cleanly implementable with libpcap's compiler, particular filter codes should be optimized differently than libpcap's internal BPF compiler does, or for security audits of emitted BPF JIT code for prepared set of BPF instructions resp. BPF JIT compiler development in general. Then, in such cases writing such a filter in low-level syntax can be an good alternative, for example, xt_bpf and cls_bpf users might have requirements that could result in more complex filter code, or one that cannot be expressed with libpcap (e.g. different return codes in cls_bpf for flowids on various BPF code paths). Moreover, BPF JIT implementors may wish to manually write test cases in order to verify the resulting JIT image, and thus need low-level access to BPF code generation as well. Therefore, complete the available toolchain for BPF with this small bpf_asm helper tool for the tools/net/ directory. These 3 complementary minimal helper tools round up and facilitate BPF development. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/net/Makefile18
-rw-r--r--tools/net/bpf_asm.c52
-rw-r--r--tools/net/bpf_exp.l143
-rw-r--r--tools/net/bpf_exp.y749
4 files changed, 960 insertions, 2 deletions
diff --git a/tools/net/Makefile b/tools/net/Makefile
index 0f30d923afa0..004cd74734b6 100644
--- a/tools/net/Makefile
+++ b/tools/net/Makefile
@@ -1,8 +1,16 @@
1prefix = /usr 1prefix = /usr
2 2
3CC = gcc 3CC = gcc
4LEX = flex
5YACC = bison
4 6
5all : bpf_jit_disasm bpf_dbg 7%.yacc.c: %.y
8 $(YACC) -o $@ -d $<
9
10%.lex.c: %.l
11 $(LEX) -o $@ $<
12
13all : bpf_jit_disasm bpf_dbg bpf_asm
6 14
7bpf_jit_disasm : CFLAGS = -Wall -O2 15bpf_jit_disasm : CFLAGS = -Wall -O2
8bpf_jit_disasm : LDLIBS = -lopcodes -lbfd -ldl 16bpf_jit_disasm : LDLIBS = -lopcodes -lbfd -ldl
@@ -12,9 +20,15 @@ bpf_dbg : CFLAGS = -Wall -O2
12bpf_dbg : LDLIBS = -lreadline 20bpf_dbg : LDLIBS = -lreadline
13bpf_dbg : bpf_dbg.o 21bpf_dbg : bpf_dbg.o
14 22
23bpf_asm : CFLAGS = -Wall -O2 -I.
24bpf_asm : LDLIBS =
25bpf_asm : bpf_asm.o bpf_exp.yacc.o bpf_exp.lex.o
26bpf_exp.lex.o : bpf_exp.yacc.c
27
15clean : 28clean :
16 rm -rf *.o bpf_jit_disasm bpf_dbg 29 rm -rf *.o bpf_jit_disasm bpf_dbg bpf_asm bpf_exp.yacc.* bpf_exp.lex.*
17 30
18install : 31install :
19 install bpf_jit_disasm $(prefix)/bin/bpf_jit_disasm 32 install bpf_jit_disasm $(prefix)/bin/bpf_jit_disasm
20 install bpf_dbg $(prefix)/bin/bpf_dbg 33 install bpf_dbg $(prefix)/bin/bpf_dbg
34 install bpf_asm $(prefix)/bin/bpf_asm
diff --git a/tools/net/bpf_asm.c b/tools/net/bpf_asm.c
new file mode 100644
index 000000000000..c15aef097b04
--- /dev/null
+++ b/tools/net/bpf_asm.c
@@ -0,0 +1,52 @@
1/*
2 * Minimal BPF assembler
3 *
4 * Instead of libpcap high-level filter expressions, it can be quite
5 * useful to define filters in low-level BPF assembler (that is kept
6 * close to Steven McCanne and Van Jacobson's original BPF paper).
7 * In particular for BPF JIT implementors, JIT security auditors, or
8 * just for defining BPF expressions that contain extensions which are
9 * not supported by compilers.
10 *
11 * How to get into it:
12 *
13 * 1) read Documentation/networking/filter.txt
14 * 2) Run `bpf_asm [-c] <filter-prog file>` to translate into binary
15 * blob that is loadable with xt_bpf, cls_bpf et al. Note: -c will
16 * pretty print a C-like construct.
17 *
18 * Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
19 * Licensed under the GNU General Public License, version 2.0 (GPLv2)
20 */
21
22#include <stdbool.h>
23#include <stdio.h>
24#include <string.h>
25
26extern void bpf_asm_compile(FILE *fp, bool cstyle);
27
28int main(int argc, char **argv)
29{
30 FILE *fp = stdin;
31 bool cstyle = false;
32 int i;
33
34 for (i = 1; i < argc; i++) {
35 if (!strncmp("-c", argv[i], 2)) {
36 cstyle = true;
37 continue;
38 }
39
40 fp = fopen(argv[i], "r");
41 if (!fp) {
42 fp = stdin;
43 continue;
44 }
45
46 break;
47 }
48
49 bpf_asm_compile(fp, cstyle);
50
51 return 0;
52}
diff --git a/tools/net/bpf_exp.l b/tools/net/bpf_exp.l
new file mode 100644
index 000000000000..bf7be77ddd62
--- /dev/null
+++ b/tools/net/bpf_exp.l
@@ -0,0 +1,143 @@
1/*
2 * BPF asm code lexer
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 <stdint.h>
25#include <stdlib.h>
26
27#include "bpf_exp.yacc.h"
28
29extern void yyerror(const char *str);
30
31%}
32
33%option align
34%option ecs
35
36%option nounput
37%option noreject
38%option noinput
39%option noyywrap
40
41%option 8bit
42%option caseless
43%option yylineno
44
45%%
46
47"ldb" { return OP_LDB; }
48"ldh" { return OP_LDH; }
49"ld" { return OP_LD; }
50"ldi" { return OP_LDI; }
51"ldx" { return OP_LDX; }
52"ldxi" { return OP_LDXI; }
53"ldxb" { return OP_LDXB; }
54"st" { return OP_ST; }
55"stx" { return OP_STX; }
56"jmp" { return OP_JMP; }
57"ja" { return OP_JMP; }
58"jeq" { return OP_JEQ; }
59"jneq" { return OP_JNEQ; }
60"jne" { return OP_JNEQ; }
61"jlt" { return OP_JLT; }
62"jle" { return OP_JLE; }
63"jgt" { return OP_JGT; }
64"jge" { return OP_JGE; }
65"jset" { return OP_JSET; }
66"add" { return OP_ADD; }
67"sub" { return OP_SUB; }
68"mul" { return OP_MUL; }
69"div" { return OP_DIV; }
70"mod" { return OP_MOD; }
71"neg" { return OP_NEG; }
72"and" { return OP_AND; }
73"xor" { return OP_XOR; }
74"or" { return OP_OR; }
75"lsh" { return OP_LSH; }
76"rsh" { return OP_RSH; }
77"ret" { return OP_RET; }
78"tax" { return OP_TAX; }
79"txa" { return OP_TXA; }
80
81"#"?("len") { return K_PKT_LEN; }
82"#"?("proto") { return K_PROTO; }
83"#"?("type") { return K_TYPE; }
84"#"?("poff") { return K_POFF; }
85"#"?("ifidx") { return K_IFIDX; }
86"#"?("nla") { return K_NLATTR; }
87"#"?("nlan") { return K_NLATTR_NEST; }
88"#"?("mark") { return K_MARK; }
89"#"?("queue") { return K_QUEUE; }
90"#"?("hatype") { return K_HATYPE; }
91"#"?("rxhash") { return K_RXHASH; }
92"#"?("cpu") { return K_CPU; }
93"#"?("vlan_tci") { return K_VLANT; }
94"#"?("vlan_pr") { return K_VLANP; }
95
96":" { return ':'; }
97"," { return ','; }
98"#" { return '#'; }
99"%" { return '%'; }
100"[" { return '['; }
101"]" { return ']'; }
102"(" { return '('; }
103")" { return ')'; }
104"x" { return 'x'; }
105"a" { return 'a'; }
106"+" { return '+'; }
107"M" { return 'M'; }
108"*" { return '*'; }
109"&" { return '&'; }
110
111([0][x][a-fA-F0-9]+) {
112 yylval.number = strtoul(yytext, NULL, 16);
113 return number;
114 }
115([0][b][0-1]+) {
116 yylval.number = strtol(yytext + 2, NULL, 2);
117 return number;
118 }
119(([0])|([-+]?[1-9][0-9]*)) {
120 yylval.number = strtol(yytext, NULL, 10);
121 return number;
122 }
123([0][0-9]+) {
124 yylval.number = strtol(yytext + 1, NULL, 8);
125 return number;
126 }
127[a-zA-Z_][a-zA-Z0-9_]+ {
128 yylval.label = strdup(yytext);
129 return label;
130 }
131
132"/*"([^\*]|\*[^/])*"*/" { /* NOP */ }
133";"[^\n]* { /* NOP */ }
134^#.* { /* NOP */ }
135[ \t]+ { /* NOP */ }
136[ \n]+ { /* NOP */ }
137
138. {
139 printf("unknown character \'%s\'", yytext);
140 yyerror("lex unknown character");
141 }
142
143%%
diff --git a/tools/net/bpf_exp.y b/tools/net/bpf_exp.y
new file mode 100644
index 000000000000..f524110643bb
--- /dev/null
+++ b/tools/net/bpf_exp.y
@@ -0,0 +1,749 @@
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(const char *label);
44static void bpf_set_jmp_label(const 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 const 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(const char *label)
598{
599 bpf_assert_max();
600 labels[curr_instr] = label;
601}
602
603static void bpf_set_jmp_label(const 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(void)
721{
722 free(labels);
723 free(labels_jt);
724 free(labels_jf);
725 free(labels_k);
726}
727
728void bpf_asm_compile(FILE *fp, bool cstyle)
729{
730 yyin = fp;
731
732 bpf_init();
733 bpf_stage_1_insert_insns();
734 bpf_stage_2_reduce_labels();
735 bpf_destroy();
736
737 if (cstyle)
738 bpf_pretty_print_c();
739 else
740 bpf_pretty_print();
741
742 if (fp != stdin)
743 fclose(yyin);
744}
745
746void yyerror(const char *str)
747{
748 exit(1);
749}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-20 17:46:01 -0500