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/* Copyright (C) 2000-2004 Boris Wesslowski */
/* $Id: netfilter.l,v 1.36 2004/03/22 21:59:24 bw Exp $ */
%option prefix="nf"
%option outfile="netfilter.c"
%option noyywrap
%{
#define YY_NO_UNPUT
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include "main.h"
#include "utils.h"
extern struct options opt;
void nf_parse_start(char *input);
void nf_parse_prefix(char *input, unsigned char mode);
void nf_parse_ip(char *input, unsigned char mode);
void nf_parse_proto(char *input);
%}
MONTH "Jan"|"Feb"|"Mar"|"Apr"|"May"|"Jun"|"Jul"|"Aug"|"Sep"|"Oct"|"Nov"|"Dec"
STRING [a-zA-Z][a-zA-Z0-9.-]*
PREFIX [ -OQ-~-]+|([ -OQ-~-]*P[ -GI-~-]*)|([ -OQ-~-]*PH[ -XZ-~-]*)|([ -OQ-~-]*PHY[ -RT-~-]*)
LOGHOST [0-9.a-zA-Z()_:-]*
DIGIT [0-9]
NUMBER {DIGIT}+
OCTET {DIGIT}{1,3}
PORT {DIGIT}{1,5}
HEXDIGIT [0-9a-fA-F]
HEXNUM "0x"{HEXDIGIT}+
PROTO "TCP"|"UDP"|"ICMP"|"ESP"|"AH"|"ICMPv6"|{NUMBER}
%%
{MONTH}[ ]{1,2}{DIGIT}{1,2}[ ]{DIGIT}{2}:{DIGIT}{2}:{DIGIT}{2}[ ]{LOGHOST} nf_parse_start(nftext);
" kernel: IN="{STRING}? nf_parse_prefix(nftext+12, NF_OPT_NOPREFIX);
" kernel: "{PREFIX}"IN="{STRING}? nf_parse_prefix(nftext+9, NF_OPT_PREFIX);
" klogd: IN="{STRING}? nf_parse_prefix(nftext+11, NF_OPT_NOPREFIX);
" klogd: "{PREFIX}"IN="{STRING}? nf_parse_prefix(nftext+8, NF_OPT_PREFIX);
" "{PREFIX}"IN="{STRING}? nf_parse_prefix(nftext+1, NF_OPT_PREFIX);
"OUT="{STRING}? /* ignore */
"PHYSIN="{STRING}? /* ignore */
"PHYSOUT="{STRING}? /* ignore */
"MAC="(({HEXDIGIT}{HEXDIGIT}:){13}{HEXDIGIT}{HEXDIGIT})? /* ignore */
"SRC="{OCTET}"."{OCTET}"."{OCTET}"."{OCTET} nf_parse_ip(nftext+4, NF_OPT_SRC);
"DST="{OCTET}"."{OCTET}"."{OCTET}"."{OCTET} nf_parse_ip(nftext+4, NF_OPT_DST);
"LEN="{NUMBER} opt.line->datalen = atoi(nftext+4);
"TOS="{HEXNUM} /* ignore */
"PREC="{HEXNUM} /* ignore */
"TTL="{NUMBER} /* ignore */
"ID="{NUMBER} /* ignore */
"CE" /* ignore */
"DF" /* ignore */
"MF" /* ignore */
"FRAG:"{NUMBER} /* ignore */
"PROTO="{PROTO} nf_parse_proto(nftext+6);
"INCOMPLETE ["{NUMBER}" bytes]" /* ignore */
"TYPE="{NUMBER} { opt.line->sport = atoi(nftext+5); opt.parser=opt.parser|NF_TYPE; }
"CODE="{NUMBER} /* ignore */
"SEQ="{NUMBER} /* ignore */
"ACK="{NUMBER} /* ignore */
"SPT="{PORT} { opt.line->sport = atoi(nftext+4); opt.parser=opt.parser|NF_SPT; }
"DPT="{PORT} { opt.line->dport = atoi(nftext+4); opt.parser=opt.parser|NF_DPT; }
"WINDOW="{NUMBER} /* ignore */
"RES="{HEXNUM} /* ignore */
"URG" opt.line->flags = opt.line->flags | TCP_URG;
"ACK" opt.line->flags = opt.line->flags | TCP_ACK;
"PSH" opt.line->flags = opt.line->flags | TCP_PSH;
"RST" opt.line->flags = opt.line->flags | TCP_RST;
"SYN" opt.line->flags = opt.line->flags | TCP_SYN;
"FIN" opt.line->flags = opt.line->flags | TCP_FIN;
"ECE" /* ignore */
"CWR" /* ignore */
"URGP="{NUMBER} /* ignore */
"OPT ("[0-9A-F]*")" /* ignore */
"SPI="{HEXNUM} /* ignore */
"GATEWAY="{OCTET}"."{OCTET}"."{OCTET}"."{OCTET} /* ignore */
"TC="{NUMBER} /* ignore */
"HOPLIMIT="{NUMBER} /* ignore */
"FLOWLBL="{NUMBER} /* ignore */
"[".+"]" /* ignore */
[ ]+ /* ignore whitespace */
[\n] return 0;
{STRING} if(opt.verbose) fprintf(stderr, "Unrecognized token: %s\n", nftext);
. if(opt.verbose) fprintf(stderr, "Unrecognized character: %s\n", nftext);
%%
void nf_parse_start(char *input)
{
int retval, day, hour, minute, second;
char smonth[3];
retval = sscanf(input,
"%3s %2d %2d:%2d:%2d %32s",
smonth, &day, &hour, &minute, &second,
opt.line->hostname);
if (retval != 6) {
return;
}
build_time(smonth, day, hour, minute, second);
opt.parser=opt.parser|NF_DATE;
}
void nf_parse_prefix(char *input, unsigned char mode)
{
size_t i=0;
if(mode == NF_OPT_PREFIX) {
while (i < strlen(input)) {
if(input[i] == 'I') {
if (input[i+1] == 'N') {
if (input[i+2] == '=') {
input[i] = '\0';
xstrncpy(opt.line->chainlabel, input, SHORTLEN);
xstrncpy(opt.line->interface, input+i+3, SHORTLEN);
break;
}
}
}
i++;
}
} else {
xstrncpy(opt.line->chainlabel, "-", SHORTLEN);
xstrncpy(opt.line->interface, input, SHORTLEN);
}
opt.parser=opt.parser|NF_IN;
}
void nf_parse_ip(char *input, unsigned char mode)
{
if (mode == NF_OPT_SRC) {
if(convert_ip(input, &opt.line->shost) == IN_ADDR_ERROR) return;
opt.parser=opt.parser|NF_SRC;
} else {
if(convert_ip(input, &opt.line->dhost) == IN_ADDR_ERROR) return;
opt.parser=opt.parser|NF_DST;
}
}
void nf_parse_proto(char *input)
{
if(isdigit((int)input[0])) {
opt.line->protocol = atoi(input);
} else {
if(strncmp(input, "TCP", 3) == 0) opt.line->protocol = 6;
else if(strncmp(input, "UDP", 3) == 0) opt.line->protocol = 17;
else if(strncmp(input, "ICMP", 4) == 0) opt.line->protocol = 1;
else if(strncmp(input, "ESP", 3) == 0) opt.line->protocol = 50;
else if(strncmp(input, "AH", 2) == 0) opt.line->protocol = 51;
else if(strncmp(input, "ICMPv6", 6) == 0) opt.line->protocol = 58;
}
if (opt.line->protocol != 0)
opt.parser=opt.parser|NF_PROTO;
}
unsigned char flex_netfilter(char *input, int linenum)
{
opt.parser = 0;
init_line();
nf_scan_string(input);
nflex();
nf_delete_buffer(YY_CURRENT_BUFFER);
xstrncpy(opt.line->branchname, "-", SHORTLEN);
opt.line->count = 1;
if (((opt.line->protocol == 6) || (opt.line->protocol == 17)) && (opt.parser == (NF_DATE|NF_PROTO|NF_IN|NF_SRC|NF_DST|NF_SPT|NF_DPT))) {
return PARSE_OK;
}
if ((opt.line->protocol == 1) && (opt.parser == (NF_DATE|NF_PROTO|NF_IN|NF_SRC|NF_DST|NF_TYPE))) {
return PARSE_OK;
}
if (((opt.line->protocol == 2) || (opt.line->protocol == 9) || (opt.line->protocol == 47) || (opt.line->protocol == 50)) && (opt.parser == (NF_DATE|NF_PROTO|NF_IN|NF_SRC|NF_DST))) {
return PARSE_OK;
}
if(opt.verbose)
fprintf(stderr, "netfilter parse error in line %d, ignoring.\n", linenum);
if(opt.verbose == 2)
fprintf(stderr, "input was: \"%s\"\n", input);
return PARSE_WRONG_FORMAT;
}
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