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/* Copyright (C) 2000-2006 Boris Wesslowski */
/* $Id: snort.l,v 1.9 2006/03/08 19:36:03 bw Exp $ */
%option prefix="snort"
%option outfile="snort.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 snort_parse_date(char *input);
void snort_parse_branch(char *input);
void snort_parse_ip(char *input, unsigned char mode);
%}
MONTH "Jan"|"Feb"|"Mar"|"Apr"|"May"|"Jun"|"Jul"|"Aug"|"Sep"|"Oct"|"Nov"|"Dec"
STRING [a-zA-Z0-9._-]*
STRING2 [ -Z\\^-~]*
STRING3 [a-zA-Z(][ a-zA-Z0-9()/._-]*[a-zA-Z)]
LOGHOST [0-9.a-zA-Z()_:-]*
DIGIT [0-9]
NUMBER {DIGIT}+
OCTET {DIGIT}{1,3}
PORT {DIGIT}{1,5}
PROTO "TCP"|"UDP"|"ICMP"
%%
{MONTH}[ ]{1,2}{DIGIT}{1,2}[ ]{DIGIT}{2}:{DIGIT}{2}:{DIGIT}{2}[ ]{LOGHOST} snort_parse_date(snorttext);
"snort: " /* ignore */
"snort["{NUMBER}"]: " /* ignore */
"["{NUMBER}":"{NUMBER}":"{DIGIT}"]" /* ignore */
{STRING3} xstrncpy(opt.line->chainlabel, snorttext, SHORTLEN); opt.parser=opt.parser|SNORT_CHAIN;
"[Classification: "{STRING2}"]" snort_parse_branch(snorttext+17);
"[Priority: "{DIGIT}"]:" /* ignore */
"{"{PROTO}"}"[ ]{OCTET}"."{OCTET}"."{OCTET}"."{OCTET} snort_parse_ip(snorttext+1, SNORT_OPT_SRC);
"{"{PROTO}"}"[ ]{OCTET}"."{OCTET}"."{OCTET}"."{OCTET}":"{PORT} snort_parse_ip(snorttext+1, SNORT_OPT_SRC|SNORT_OPT_PORT);
"-> "{OCTET}"."{OCTET}"."{OCTET}"."{OCTET} snort_parse_ip(snorttext, SNORT_OPT_DST);
"-> "{OCTET}"."{OCTET}"."{OCTET}"."{OCTET}":"{PORT} snort_parse_ip(snorttext, SNORT_OPT_DST|SNORT_OPT_PORT);
"spp_portscan: ".* opt.parser=SNORT_NO_HIT;
"spp_stream4: ".* opt.parser=SNORT_NO_HIT;
[ ]+ /* ignore whitespace */
[\n] /* ignore */
{STRING} if(opt.verbose) fprintf(stderr, "Unrecognized token: %s\n", snorttext);
. if(opt.verbose) fprintf(stderr, "Unrecognized character: %s\n", snorttext);
%%
void snort_parse_date(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|SNORT_DATE;
}
void snort_parse_branch(char *input)
{
char *ptr;
ptr = strchr(input, ']');
*ptr = '\0';
xstrncpy(opt.line->branchname, input, SHORTLEN);
opt.parser=opt.parser|SNORT_BRANCH;
}
void snort_parse_ip(char *input, unsigned char mode)
{
char ip[IPLEN];
int retval, host1, host2, host3, host4;
if ((mode & SNORT_OPT_SRC) != 0) {
char proto[8];
if ((mode & SNORT_OPT_PORT) != 0) {
retval = sscanf(input, "%8s %3d.%3d.%3d.%3d:%5d",
proto,
&host1, &host2, &host3, &host4,
&opt.line->sport);
if(retval != 6) return;
} else {
retval = sscanf(input, "%8s %3d.%3d.%3d.%3d",
proto,
&host1, &host2, &host3, &host4);
if(retval != 5) return;
}
if(strncmp(proto, "TCP", 3) == 0) opt.line->protocol = 6;
else if(strncmp(proto, "UDP", 3) == 0) opt.line->protocol = 17;
else if(strncmp(proto, "ICMP", 4) == 0) opt.line->protocol = 1;
if (opt.line->protocol != 0)
opt.parser=opt.parser|SNORT_PROTO;
} else if ((mode & SNORT_OPT_DST) != 0) {
if ((mode & SNORT_OPT_PORT) != 0) {
retval = sscanf(input, "-> %3d.%3d.%3d.%3d:%5d",
&host1, &host2, &host3, &host4,
&opt.line->sport);
if(retval != 5) return;
} else {
retval = sscanf(input, "-> %3d.%3d.%3d.%3d",
&host1, &host2, &host3, &host4);
if(retval != 4) return;
}
} else {
return;
}
snprintf(ip, IPLEN, "%d.%d.%d.%d", host1, host2, host3, host4);
if ((mode & SNORT_OPT_SRC) != 0) {
if(convert_ip(ip, &opt.line->shost) == IN_ADDR_ERROR) return;
opt.parser=opt.parser|SNORT_SRC;
} else if ((mode & SNORT_OPT_DST) != 0) {
if(convert_ip(ip, &opt.line->dhost) == IN_ADDR_ERROR) return;
opt.parser=opt.parser|SNORT_DST;
}
}
unsigned char flex_snort(char *input, int linenum)
{
opt.parser = 0;
init_line();
snort_scan_string(input);
snortlex();
snort_delete_buffer(YY_CURRENT_BUFFER);
xstrncpy(opt.line->interface, "-", SHORTLEN);
opt.line->count = 1;
if (opt.parser & SNORT_NO_HIT)
return PARSE_NO_HIT;
if (opt.parser == (SNORT_DATE|SNORT_CHAIN|SNORT_BRANCH|SNORT_PROTO|SNORT_SRC|SNORT_DST)) {
return PARSE_OK;
} else {
if(opt.verbose)
fprintf(stderr, "snort 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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