source: freewrt/package/iptables/patches/02-layer7-1.5nbd.patch@ 475ad56

extensions/.layer7-test

@@ +1 @@
+#! /bin/sh
+[ -f $KERNEL_DIR/include/linux/netfilter_ipv4/ipt_layer7.h ] && echo layer7

extensions/ipt_layer7.h

@@ +1 @@
+/* 
+  By Matthew Strait <quadong@users.sf.net>, Dec 2003.
+  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
+*/
+
+#ifndef _IPT_LAYER7_H
+#define _IPT_LAYER7_H
+
+#define MAX_PATTERN_LEN 8192
+#define MAX_PROTOCOL_LEN 256
+
+typedef char *(*proc_ipt_search) (char *, char, char *);
+
+struct ipt_layer7_info {
+    char protocol[MAX_PROTOCOL_LEN];
+    char invert:1;
+    char pattern[MAX_PATTERN_LEN];
+        char pkt;
+};
+
+#endif /* _IPT_LAYER7_H */

extensions/libipt_layer7.c

@@ +1 @@
+/* 
+   Shared library add-on to iptables to add layer 7 matching support. 
+  
+   By Matthew Strait <quadong@users.sf.net>, Oct 2003.
+
+   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
+
+   Based on libipt_string.c (C) 2000 Emmanuel Roger <winfield@freegates.be>
+*/
+
+#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 <iptables.h>
+#include "ipt_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 v%s 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 the protocol defined in /etc/l7-protocols/name.pat\n"
+        "--l7pkt              : Skip connection tracking and match individual packets\n",
+        IPTABLES_VERSION);
+        fputc('\n', stdout);
+}
+
+static struct option opts[] = {
+        { .name = "l7proto", .has_arg = 1, .flag = 0, .val = '1' },
+        { .name = "l7dir",   .has_arg = 1, .flag = 0, .val = '2' },
+        { .name = "l7pkt",   .has_arg = 0, .flag = 0, .val = '3' },
+        { .name = 0 }
+};
+
+/* reads filename, puts protocol info into layer7_protocol_info, number of protocols to numprotos */
+int parse_protocol_file(char * filename, const unsigned char * protoname, struct ipt_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)
+                {
+                        if(strcmp(line, protoname))
+                                exit_error(OTHER_PROBLEM, 
+                                        "Protocol name (%s) doesn't match file name (%s).  Bailing out\n",
+                                        protoname, filename);
+
+                        if(strlen(line) >= MAX_PROTOCOL_LEN)
+                                 exit_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)
+                                 exit_error(PARAMETER_PROBLEM, "Pattern in %s too long!", filename);
+                        strncpy(info->pattern, line, MAX_PATTERN_LEN);
+                        
+                        datatype = done;                        
+                        break;
+                }
+                else
+                        exit_error(OTHER_PROBLEM, "Internal error");
+        }
+
+        if(datatype != done)
+                exit_error(OTHER_PROBLEM, "Failed to get all needed data from %s", filename);
+
+        if(line) free(line);
+        fclose(f);
+
+        return 1;
+
+/*
+        fprintf(stderr, "protocol: %s\npattern: %s\n\n", 
+                        info->protocol,
+                        info->pattern);
+*/
+}
+
+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:
+                        exit_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, rindex = 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[rindex] = tolower( hex2dec(s[sindex + 2])*16 +
+                                                  hex2dec(s[sindex + 3] ) );
+                        sindex += 3; /* 4 total */
+                }
+                else
+                        result[rindex] = tolower(s[sindex]);
+
+                sindex++; 
+                rindex++;
+        }
+        result[rindex] = '\0';
+
+        return result;
+}
+
+#define MAX_SUBDIRS 128
+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");
+            exit_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 unsigned char *s, struct ipt_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);
+
+                //fprintf(stderr, "Trying to find pattern in %s ... ", filename);
+
+                if(c > MAX_FN_LEN)
+                {
+                        exit_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))
+                {
+                        //fprintf(stderr, "found\n");
+                        done = 1;
+                        break;
+                }
+                
+                //fprintf(stderr, "not found\n");
+
+                n++;
+        }
+
+        if(!done)
+                exit_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 struct ipt_entry *entry, unsigned int *nfcache,
+      struct ipt_entry_match **match)
+{
+        struct ipt_layer7_info *layer7info = 
+                (struct ipt_layer7_info *)(*match)->data;
+
+        switch (c) {
+        case '1':
+                check_inverse(optarg, &invert, &optind, 0);
+                parse_layer7_protocol(argv[optind-1], layer7info);
+                if (invert)
+                        layer7info->invert = 1;
+                *flags = 1;
+                break;
+
+        case '2':
+                /* not going to use this, but maybe we need to strip a ! anyway (?) */
+                check_inverse(optarg, &invert, &optind, 0);
+
+                if(strlen(argv[optind-1]) >= MAX_FN_LEN)
+                        exit_error(PARAMETER_PROBLEM, "directory name too long\n");
+
+                strncpy(l7dir, argv[optind-1], MAX_FN_LEN);
+
+                *flags = 1;
+                break;
+        case '3':
+                layer7info->pkt = 1;
+                break;
+
+        default:
+                return 0;
+        }
+
+        return 1;
+}
+
+/* Final check; must have specified --pattern. */
+static void final_check(unsigned int flags)
+{
+        if (!flags)
+                exit_error(PARAMETER_PROBLEM,
+                           "LAYER7 match: You must specify `--pattern'");
+}
+
+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 struct ipt_ip *ip,
+      const struct ipt_entry_match *match,
+      int numeric)
+{
+        printf("LAYER7 ");
+
+        print_protocol(((struct ipt_layer7_info *)match->data)->protocol,
+                  ((struct ipt_layer7_info *)match->data)->invert, numeric);
+
+        if (((struct ipt_layer7_info *)match->data)->pkt)
+                printf("l7pkt ");
+}
+/* Saves the union ipt_matchinfo in parsable form to stdout. */
+static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
+{
+        const struct ipt_layer7_info *info =
+            (const struct ipt_layer7_info*) match->data;
+
+        printf("--l7proto %s%s ", (info->invert)   ? "! ": "", info->protocol);
+}
+
+static struct iptables_match layer7 = { 
+    .name          = "layer7",
+    .version       = IPTABLES_VERSION,
+    .size          = IPT_ALIGN(sizeof(struct ipt_layer7_info)),
+    .userspacesize = IPT_ALIGN(sizeof(struct ipt_layer7_info)),
+    .help          = &help,
+    .parse         = &parse,
+    .final_check   = &final_check,
+    .print         = &print,
+    .save          = &save,
+    .extra_opts    = opts
+};
+
+void _init(void)
+{
+        register_match(&layer7);
+}

extensions/libipt_layer7.man

@@ +1 @@
+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/
+.TP
+.BI "--l7dir " "\fIdirectory\fP"
+Use \fIdirectory\fP instead of /etc/l7-protocols/
+