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4cd3675ebf
Added a new ancillary load (bpf call in eBPF parlance) that produces a 32-bit random number. We are implementing it as an ancillary load (instead of an ISA opcode) because (a) it is simpler, (b) allows easy JITing, and (c) seems more in line with generic ISAs that do not have "get a random number" as a instruction, but as an OS call. The main use for this ancillary load is to perform random packet sampling. Signed-off-by: Chema Gonzalez <chema@google.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
144 lines
3.3 KiB
Text
144 lines
3.3 KiB
Text
/*
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* BPF asm code lexer
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*
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* This program is free software; you can distribute it and/or modify
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* it under the terms of the GNU General Public License as published
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* by the Free Software Foundation; either version 2 of the License,
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* or (at your option) any later version.
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*
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* Syntax kept close to:
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*
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* Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new
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* architecture for user-level packet capture. In Proceedings of the
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* USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993
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* Conference Proceedings (USENIX'93). USENIX Association, Berkeley,
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* CA, USA, 2-2.
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*
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* Copyright 2013 Daniel Borkmann <borkmann@redhat.com>
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* Licensed under the GNU General Public License, version 2.0 (GPLv2)
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*/
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%{
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include "bpf_exp.yacc.h"
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extern void yyerror(const char *str);
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%}
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%option align
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%option ecs
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%option nounput
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%option noreject
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%option noinput
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%option noyywrap
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%option 8bit
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%option caseless
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%option yylineno
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%%
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"ldb" { return OP_LDB; }
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"ldh" { return OP_LDH; }
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"ld" { return OP_LD; }
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"ldi" { return OP_LDI; }
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"ldx" { return OP_LDX; }
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"ldxi" { return OP_LDXI; }
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"ldxb" { return OP_LDXB; }
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"st" { return OP_ST; }
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"stx" { return OP_STX; }
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"jmp" { return OP_JMP; }
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"ja" { return OP_JMP; }
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"jeq" { return OP_JEQ; }
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"jneq" { return OP_JNEQ; }
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"jne" { return OP_JNEQ; }
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"jlt" { return OP_JLT; }
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"jle" { return OP_JLE; }
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"jgt" { return OP_JGT; }
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"jge" { return OP_JGE; }
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"jset" { return OP_JSET; }
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"add" { return OP_ADD; }
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"sub" { return OP_SUB; }
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"mul" { return OP_MUL; }
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"div" { return OP_DIV; }
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"mod" { return OP_MOD; }
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"neg" { return OP_NEG; }
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"and" { return OP_AND; }
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"xor" { return OP_XOR; }
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"or" { return OP_OR; }
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"lsh" { return OP_LSH; }
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"rsh" { return OP_RSH; }
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"ret" { return OP_RET; }
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"tax" { return OP_TAX; }
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"txa" { return OP_TXA; }
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"#"?("len") { return K_PKT_LEN; }
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"#"?("proto") { return K_PROTO; }
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"#"?("type") { return K_TYPE; }
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"#"?("poff") { return K_POFF; }
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"#"?("ifidx") { return K_IFIDX; }
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"#"?("nla") { return K_NLATTR; }
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"#"?("nlan") { return K_NLATTR_NEST; }
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"#"?("mark") { return K_MARK; }
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"#"?("queue") { return K_QUEUE; }
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"#"?("hatype") { return K_HATYPE; }
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"#"?("rxhash") { return K_RXHASH; }
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"#"?("cpu") { return K_CPU; }
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"#"?("vlan_tci") { return K_VLANT; }
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"#"?("vlan_pr") { return K_VLANP; }
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"#"?("rand") { return K_RAND; }
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":" { return ':'; }
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"," { return ','; }
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"#" { return '#'; }
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"%" { return '%'; }
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"[" { return '['; }
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"]" { return ']'; }
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"(" { return '('; }
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")" { return ')'; }
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"x" { return 'x'; }
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"a" { return 'a'; }
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"+" { return '+'; }
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"M" { return 'M'; }
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"*" { return '*'; }
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"&" { return '&'; }
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([0][x][a-fA-F0-9]+) {
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yylval.number = strtoul(yytext, NULL, 16);
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return number;
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}
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([0][b][0-1]+) {
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yylval.number = strtol(yytext + 2, NULL, 2);
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return number;
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}
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(([0])|([-+]?[1-9][0-9]*)) {
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yylval.number = strtol(yytext, NULL, 10);
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return number;
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}
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([0][0-9]+) {
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yylval.number = strtol(yytext + 1, NULL, 8);
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return number;
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}
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[a-zA-Z_][a-zA-Z0-9_]+ {
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yylval.label = strdup(yytext);
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return label;
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}
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"/*"([^\*]|\*[^/])*"*/" { /* NOP */ }
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";"[^\n]* { /* NOP */ }
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^#.* { /* NOP */ }
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[ \t]+ { /* NOP */ }
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[ \n]+ { /* NOP */ }
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. {
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printf("unknown character \'%s\'", yytext);
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yyerror("lex unknown character");
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}
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%%
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