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openwrt-xburst/package/iptables/patches/002-layer7_2.17.patch
juhosg 10b8a21dd1 package/iptables: refresh patches 
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@20465 3c298f89-4303-0410-b956-a3cf2f4a3e73
2010-03-26 14:28:40 +00:00

389 lines
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--- /dev/null
+++ b/extensions/libxt_layer7.c
@@ -0,0 +1,368 @@
+/*
+ Shared library add-on to iptables for layer 7 matching support.
+
+ By Matthew Strait <quadong@users.sf.net>, Oct 2003-Aug 2008.
+
+ http://l7-filter.sf.net
+
+ This program is free software; you can redistribute 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.
+ http://www.gnu.org/licenses/gpl.txt
+*/
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <ctype.h>
+#include <dirent.h>
+
+#include <xtables.h>
+#include <linux/netfilter/xt_layer7.h>
+
+#define MAX_FN_LEN 256
+
+static char l7dir[MAX_FN_LEN] = "\0";
+
+/* Function which prints out usage message. */
+static void help(void)
+{
+ printf(
+ "layer7 match options:\n"
+ " --l7dir <directory> : Look for patterns here instead of /etc/l7-protocols/\n"
+ " (--l7dir must be specified before --l7proto if used)\n"
+ "[!] --l7proto <name>: Match named protocol using /etc/l7-protocols/.../name.pat\n");
+}
+
+static const struct option opts[] = {
+ { .name = "l7proto", .has_arg = 1, .val = 'p' },
+ { .name = "l7dir", .has_arg = 1, .val = 'd' },
+ { .name = NULL }
+};
+
+/* reads filename, puts protocol info into layer7_protocol_info, number of protocols to numprotos */
+static int parse_protocol_file(char * filename, const char * protoname, struct xt_layer7_info *info)
+{
+ FILE * f;
+ char * line = NULL;
+ size_t len = 0;
+
+ enum { protocol, pattern, done } datatype = protocol;
+
+ f = fopen(filename, "r");
+
+ if(!f)
+ return 0;
+
+ while(getline(&line, &len, f) != -1)
+ {
+ if(strlen(line) < 2 || line[0] == '#')
+ continue;
+
+ /* strip the pesky newline... */
+ if(line[strlen(line) - 1] == '\n')
+ line[strlen(line) - 1] = '\0';
+
+ if(datatype == protocol)
+ {
+ /* Ignore everything on the line beginning with the
+ first space or tab . For instance, this allows the
+ protocol line in http.pat to be "http " (or
+ "http I am so cool") instead of just "http". */
+ if(strchr(line, ' ')){
+ char * space = strchr(line, ' ');
+ space[0] = '\0';
+ }
+ if(strchr(line, '\t')){
+ char * space = strchr(line, '\t');
+ space[0] = '\0';
+ }
+
+ /* sanity check. First non-comment non-blank
+ line must be the same as the file name. */
+ if(strcmp(line, protoname))
+ xtables_error(OTHER_PROBLEM,
+ "Protocol name (%s) doesn't match file name (%s). Bailing out\n",
+ line, filename);
+
+ if(strlen(line) >= MAX_PROTOCOL_LEN)
+ xtables_error(PARAMETER_PROBLEM,
+ "Protocol name in %s too long!", filename);
+ strncpy(info->protocol, line, MAX_PROTOCOL_LEN);
+
+ datatype = pattern;
+ }
+ else if(datatype == pattern)
+ {
+ if(strlen(line) >= MAX_PATTERN_LEN)
+ xtables_error(PARAMETER_PROBLEM, "Pattern in %s too long!", filename);
+ strncpy(info->pattern, line, MAX_PATTERN_LEN);
+
+ datatype = done;
+ break;
+ }
+ else
+ xtables_error(OTHER_PROBLEM, "Internal error");
+ }
+
+ if(datatype != done)
+ xtables_error(OTHER_PROBLEM, "Failed to get all needed data from %s", filename);
+
+ if(line) free(line);
+ fclose(f);
+
+ return 1;
+}
+
+static int hex2dec(char c)
+{
+ switch (c)
+ {
+ case '0' ... '9':
+ return c - '0';
+ case 'a' ... 'f':
+ return c - 'a' + 10;
+ case 'A' ... 'F':
+ return c - 'A' + 10;
+ default:
+ xtables_error(OTHER_PROBLEM, "hex2dec: bad value!\n");
+ return 0;
+ }
+}
+
+/* takes a string with \xHH escapes and returns one with the characters
+they stand for */
+static char * pre_process(char * s)
+{
+ char * result = malloc(strlen(s) + 1);
+ int sindex = 0, rrindex = 0;
+ while( sindex < strlen(s) )
+ {
+ if( sindex + 3 < strlen(s) &&
+ s[sindex] == '\\' && s[sindex+1] == 'x' &&
+ isxdigit(s[sindex + 2]) && isxdigit(s[sindex + 3]) )
+ {
+ /* carefully remember to call tolower here... */
+ result[rrindex] = tolower( hex2dec(s[sindex + 2])*16 +
+ hex2dec(s[sindex + 3] ) );
+
+ switch ( result[rrindex] )
+ {
+ case 0x24:
+ case 0x28:
+ case 0x29:
+ case 0x2a:
+ case 0x2b:
+ case 0x2e:
+ case 0x3f:
+ case 0x5b:
+ case 0x5c:
+ case 0x5d:
+ case 0x5e:
+ case 0x7c:
+ fprintf(stderr,
+ "Warning: layer7 regexp contains a control character, %c, in hex (\\x%c%c).\n"
+ "I recommend that you write this as %c or \\%c, depending on what you meant.\n",
+ result[rrindex], s[sindex + 2], s[sindex + 3], result[rrindex], result[rrindex]);
+ break;
+ case 0x00:
+ fprintf(stderr,
+ "Warning: null (\\x00) in layer7 regexp. A null terminates the regexp string!\n");
+ break;
+ default:
+ break;
+ }
+
+
+ sindex += 3; /* 4 total */
+ }
+ else
+ result[rrindex] = tolower(s[sindex]);
+
+ sindex++;
+ rrindex++;
+ }
+ result[rrindex] = '\0';
+
+ return result;
+}
+
+#define MAX_SUBDIRS 128
+static char ** readl7dir(char * dirname)
+{
+ DIR * scratchdir;
+ struct dirent ** namelist;
+ char ** subdirs = malloc(MAX_SUBDIRS * sizeof(char *));
+
+ int n, d = 1;
+ subdirs[0] = "";
+
+ n = scandir(dirname, &namelist, 0, alphasort);
+
+ if (n < 0)
+ {
+ perror("scandir");
+ xtables_error(OTHER_PROBLEM, "Couldn't open %s\n", dirname);
+ }
+ else
+ {
+ while(n--)
+ {
+ char fulldirname[MAX_FN_LEN];
+
+ snprintf(fulldirname, MAX_FN_LEN, "%s/%s", dirname, namelist[n]->d_name);
+
+ if((scratchdir = opendir(fulldirname)) != NULL)
+ {
+ closedir(scratchdir);
+
+ if(!strcmp(namelist[n]->d_name, ".") ||
+ !strcmp(namelist[n]->d_name, ".."))
+ /* do nothing */ ;
+ else
+ {
+ subdirs[d] = malloc(strlen(namelist[n]->d_name) + 1);
+ strcpy(subdirs[d], namelist[n]->d_name);
+ d++;
+ if(d >= MAX_SUBDIRS - 1)
+ {
+ fprintf(stderr,
+ "Too many subdirectories, skipping the rest!\n");
+ break;
+ }
+ }
+ }
+ free(namelist[n]);
+ }
+ free(namelist);
+ }
+
+ subdirs[d] = NULL;
+
+ return subdirs;
+}
+
+static void parse_layer7_protocol(const char *s, struct xt_layer7_info *info)
+{
+ char filename[MAX_FN_LEN];
+ char * dir = NULL;
+ char ** subdirs;
+ int n = 0, done = 0;
+
+ if(strlen(l7dir) > 0) dir = l7dir;
+ else dir = "/etc/l7-protocols";
+
+ subdirs = readl7dir(dir);
+
+ while(subdirs[n] != NULL)
+ {
+ int c = snprintf(filename, MAX_FN_LEN, "%s/%s/%s.pat", dir, subdirs[n], s);
+
+ if(c > MAX_FN_LEN)
+ xtables_error(OTHER_PROBLEM,
+ "Filename beginning with %s is too long!\n", filename);
+
+ /* read in the pattern from the file */
+ if(parse_protocol_file(filename, s, info)){
+ done = 1;
+ break;
+ }
+
+ n++;
+ }
+
+ if(!done)
+ xtables_error(OTHER_PROBLEM,
+ "Couldn't find a pattern definition file for %s.\n", s);
+
+ /* process \xHH escapes and tolower everything. (our regex lib has no
+ case insensitivity option.) */
+ strncpy(info->pattern, pre_process(info->pattern), MAX_PATTERN_LEN);
+}
+
+/* Function which parses command options; returns true if it ate an option */
+static int parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry, struct xt_entry_match **match)
+{
+ struct xt_layer7_info *layer7info =
+ (struct xt_layer7_info *)(*match)->data;
+
+ switch (c) {
+ case 'p':
+ parse_layer7_protocol(argv[optind-1], layer7info);
+ if (invert)
+ layer7info->invert = true;
+ *flags = 1;
+ break;
+
+ case 'd':
+ if(strlen(argv[optind-1]) >= MAX_FN_LEN)
+ xtables_error(PARAMETER_PROBLEM, "directory name too long\n");
+
+ strncpy(l7dir, argv[optind-1], MAX_FN_LEN);
+
+ *flags = 1;
+ break;
+
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Final check; must have specified --l7proto */
+static void final_check(unsigned int flags)
+{
+ if (!flags)
+ xtables_error(PARAMETER_PROBLEM,
+ "LAYER7 match: You must specify `--l7proto'");
+}
+
+static void print_protocol(char s[], int invert, int numeric)
+{
+ fputs("l7proto ", stdout);
+ if (invert) fputc('!', stdout);
+ printf("%s ", s);
+}
+
+/* Prints out the matchinfo. */
+static void print(const void *ip,
+ const struct xt_entry_match *match,
+ int numeric)
+{
+ printf("LAYER7 ");
+ print_protocol(((struct xt_layer7_info *)match->data)->protocol,
+ ((struct xt_layer7_info *)match->data)->invert, numeric);
+}
+/* Saves the union ipt_matchinfo in parsable form to stdout. */
+static void save(const void *ip, const struct xt_entry_match *match)
+{
+ const struct xt_layer7_info *info =
+ (const struct xt_layer7_info*) match->data;
+
+ printf("--l7proto %s%s ", (info->invert)? "! ":"", info->protocol);
+}
+
+static struct xtables_match layer7 = {
+ .family = AF_INET,
+ .name = "layer7",
+ .version = XTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_layer7_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_layer7_info)),
+ .help = &help,
+ .parse = &parse,
+ .final_check = &final_check,
+ .print = &print,
+ .save = &save,
+ .extra_opts = opts
+};
+
+void _init(void)
+{
+ xtables_register_match(&layer7);
+}
--- /dev/null
+++ b/extensions/libxt_layer7.man
@@ -0,0 +1,14 @@
+This module matches packets based on the application layer data of
+their connections. It uses regular expression matching to compare
+the application layer data to regular expressions found it the layer7
+configuration files. This is an experimental module which can be found at
+http://l7-filter.sf.net. It takes two options.
+.TP
+.BI "--l7proto " "\fIprotocol\fP"
+Match the specified protocol. The protocol name must match a file
+name in /etc/l7-protocols/ or one of its first-level child directories.
+.TP
+.BI "--l7dir " "\fIdirectory\fP"
+Use \fIdirectory\fP instead of /etc/l7-protocols/. This option must be
+specified before --l7proto.
+
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