diff --git a/tools/net/Makefile b/tools/net/Makefile index 0f30d923afa05e8747988ea19292ed6370e860bd..004cd74734b62b941cf64db1634d2774f70f6e3c 100644 --- a/tools/net/Makefile +++ b/tools/net/Makefile @@ -1,8 +1,16 @@ prefix = /usr CC = gcc +LEX = flex +YACC = bison -all : bpf_jit_disasm bpf_dbg +%.yacc.c: %.y + $(YACC) -o $@ -d $< + +%.lex.c: %.l + $(LEX) -o $@ $< + +all : bpf_jit_disasm bpf_dbg bpf_asm bpf_jit_disasm : CFLAGS = -Wall -O2 bpf_jit_disasm : LDLIBS = -lopcodes -lbfd -ldl @@ -12,9 +20,15 @@ bpf_dbg : CFLAGS = -Wall -O2 bpf_dbg : LDLIBS = -lreadline bpf_dbg : bpf_dbg.o +bpf_asm : CFLAGS = -Wall -O2 -I. +bpf_asm : LDLIBS = +bpf_asm : bpf_asm.o bpf_exp.yacc.o bpf_exp.lex.o +bpf_exp.lex.o : bpf_exp.yacc.c + clean : - rm -rf *.o bpf_jit_disasm bpf_dbg + rm -rf *.o bpf_jit_disasm bpf_dbg bpf_asm bpf_exp.yacc.* bpf_exp.lex.* install : install bpf_jit_disasm $(prefix)/bin/bpf_jit_disasm install bpf_dbg $(prefix)/bin/bpf_dbg + 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 0000000000000000000000000000000000000000..c15aef097b044164f6ad377f0eef820deeaac54e --- /dev/null +++ b/tools/net/bpf_asm.c @@ -0,0 +1,52 @@ +/* + * Minimal BPF assembler + * + * Instead of libpcap high-level filter expressions, it can be quite + * useful to define filters in low-level BPF assembler (that is kept + * close to Steven McCanne and Van Jacobson's original BPF paper). + * In particular for BPF JIT implementors, JIT security auditors, or + * just for defining BPF expressions that contain extensions which are + * not supported by compilers. + * + * How to get into it: + * + * 1) read Documentation/networking/filter.txt + * 2) Run `bpf_asm [-c] ` to translate into binary + * blob that is loadable with xt_bpf, cls_bpf et al. Note: -c will + * pretty print a C-like construct. + * + * Copyright 2013 Daniel Borkmann + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +#include +#include +#include + +extern void bpf_asm_compile(FILE *fp, bool cstyle); + +int main(int argc, char **argv) +{ + FILE *fp = stdin; + bool cstyle = false; + int i; + + for (i = 1; i < argc; i++) { + if (!strncmp("-c", argv[i], 2)) { + cstyle = true; + continue; + } + + fp = fopen(argv[i], "r"); + if (!fp) { + fp = stdin; + continue; + } + + break; + } + + bpf_asm_compile(fp, cstyle); + + return 0; +} diff --git a/tools/net/bpf_exp.l b/tools/net/bpf_exp.l new file mode 100644 index 0000000000000000000000000000000000000000..bf7be77ddd621238aa2a26ca2103b309bdcd089f --- /dev/null +++ b/tools/net/bpf_exp.l @@ -0,0 +1,143 @@ +/* + * BPF asm code lexer + * + * This program is free software; you can distribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, + * or (at your option) any later version. + * + * Syntax kept close to: + * + * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new + * architecture for user-level packet capture. In Proceedings of the + * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993 + * Conference Proceedings (USENIX'93). USENIX Association, Berkeley, + * CA, USA, 2-2. + * + * Copyright 2013 Daniel Borkmann + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +%{ + +#include +#include +#include + +#include "bpf_exp.yacc.h" + +extern void yyerror(const char *str); + +%} + +%option align +%option ecs + +%option nounput +%option noreject +%option noinput +%option noyywrap + +%option 8bit +%option caseless +%option yylineno + +%% + +"ldb" { return OP_LDB; } +"ldh" { return OP_LDH; } +"ld" { return OP_LD; } +"ldi" { return OP_LDI; } +"ldx" { return OP_LDX; } +"ldxi" { return OP_LDXI; } +"ldxb" { return OP_LDXB; } +"st" { return OP_ST; } +"stx" { return OP_STX; } +"jmp" { return OP_JMP; } +"ja" { return OP_JMP; } +"jeq" { return OP_JEQ; } +"jneq" { return OP_JNEQ; } +"jne" { return OP_JNEQ; } +"jlt" { return OP_JLT; } +"jle" { return OP_JLE; } +"jgt" { return OP_JGT; } +"jge" { return OP_JGE; } +"jset" { return OP_JSET; } +"add" { return OP_ADD; } +"sub" { return OP_SUB; } +"mul" { return OP_MUL; } +"div" { return OP_DIV; } +"mod" { return OP_MOD; } +"neg" { return OP_NEG; } +"and" { return OP_AND; } +"xor" { return OP_XOR; } +"or" { return OP_OR; } +"lsh" { return OP_LSH; } +"rsh" { return OP_RSH; } +"ret" { return OP_RET; } +"tax" { return OP_TAX; } +"txa" { return OP_TXA; } + +"#"?("len") { return K_PKT_LEN; } +"#"?("proto") { return K_PROTO; } +"#"?("type") { return K_TYPE; } +"#"?("poff") { return K_POFF; } +"#"?("ifidx") { return K_IFIDX; } +"#"?("nla") { return K_NLATTR; } +"#"?("nlan") { return K_NLATTR_NEST; } +"#"?("mark") { return K_MARK; } +"#"?("queue") { return K_QUEUE; } +"#"?("hatype") { return K_HATYPE; } +"#"?("rxhash") { return K_RXHASH; } +"#"?("cpu") { return K_CPU; } +"#"?("vlan_tci") { return K_VLANT; } +"#"?("vlan_pr") { return K_VLANP; } + +":" { return ':'; } +"," { return ','; } +"#" { return '#'; } +"%" { return '%'; } +"[" { return '['; } +"]" { return ']'; } +"(" { return '('; } +")" { return ')'; } +"x" { return 'x'; } +"a" { return 'a'; } +"+" { return '+'; } +"M" { return 'M'; } +"*" { return '*'; } +"&" { return '&'; } + +([0][x][a-fA-F0-9]+) { + yylval.number = strtoul(yytext, NULL, 16); + return number; + } +([0][b][0-1]+) { + yylval.number = strtol(yytext + 2, NULL, 2); + return number; + } +(([0])|([-+]?[1-9][0-9]*)) { + yylval.number = strtol(yytext, NULL, 10); + return number; + } +([0][0-9]+) { + yylval.number = strtol(yytext + 1, NULL, 8); + return number; + } +[a-zA-Z_][a-zA-Z0-9_]+ { + yylval.label = strdup(yytext); + return label; + } + +"/*"([^\*]|\*[^/])*"*/" { /* NOP */ } +";"[^\n]* { /* NOP */ } +^#.* { /* NOP */ } +[ \t]+ { /* NOP */ } +[ \n]+ { /* NOP */ } + +. { + printf("unknown character \'%s\'", yytext); + yyerror("lex unknown character"); + } + +%% diff --git a/tools/net/bpf_exp.y b/tools/net/bpf_exp.y new file mode 100644 index 0000000000000000000000000000000000000000..f524110643bbc2a9500fd7869002edac2683fe02 --- /dev/null +++ b/tools/net/bpf_exp.y @@ -0,0 +1,749 @@ +/* + * BPF asm code parser + * + * This program is free software; you can distribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, + * or (at your option) any later version. + * + * Syntax kept close to: + * + * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new + * architecture for user-level packet capture. In Proceedings of the + * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993 + * Conference Proceedings (USENIX'93). USENIX Association, Berkeley, + * CA, USA, 2-2. + * + * Copyright 2013 Daniel Borkmann + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +%{ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "bpf_exp.yacc.h" + +enum jmp_type { JTL, JFL, JKL }; + +extern FILE *yyin; +extern int yylex(void); +extern void yyerror(const char *str); + +extern void bpf_asm_compile(FILE *fp, bool cstyle); +static void bpf_set_curr_instr(uint16_t op, uint8_t jt, uint8_t jf, uint32_t k); +static void bpf_set_curr_label(const char *label); +static void bpf_set_jmp_label(const char *label, enum jmp_type type); + +%} + +%union { + char *label; + uint32_t number; +} + +%token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE +%token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH +%token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI +%token OP_LDXI + +%token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE +%token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF + +%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%' + +%token number label + +%type