Emmanuel Roger's string matching patch.

diff --git a/extensions/.string-test b/extensions/.string-test
new file mode 100755 (executable)
index 0000000..609f1c2
--- /dev/null
+++ b/extensions/.string-test
@@ -0,0 +1,2 @@
+#! /bin/sh
+[ -f $KERNEL_DIR/include/linux/netfilter_ipv4/ipt_string.h ] && echo string

diff --git a/extensions/libipt_string.c b/extensions/libipt_string.c
new file mode 100644 (file)
index 0000000..25dacdc
--- /dev/null
+++ b/extensions/libipt_string.c
@@ -0,0 +1,127 @@
+/* Shared library add-on to iptables to add string matching support. 
+ * 
+ * Copyright (C) 2000 Emmanuel Roger  <winfield@freegates.be>
+ */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ipt_string.h>
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+       printf(
+"STRING match v%s options:\n"
+"--string [!] string             Match a string in a packet\n",
+NETFILTER_VERSION);
+
+       fputc('\n', stdout);
+}
+
+static struct option opts[] = {
+       { "string", 1, 0, '1' },
+       {0}
+};
+
+/* Initialize the match. */
+static void
+init(struct ipt_entry_match *m, unsigned int *nfcache)
+{
+       *nfcache |= NFC_UNKNOWN;
+}
+
+static void
+parse_string(const unsigned char *s, struct ipt_string_info *info)
+{      
+       if (strlen(s) <= 255) strcpy(info->string, s);
+       else exit_error(PARAMETER_PROBLEM, "STRING too long `%s'", s);
+}
+
+/* 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_string_info *stringinfo = (struct ipt_string_info *)(*match)->data;
+
+       switch (c) {
+       case '1':
+               if (check_inverse(optarg, &invert))
+                       optind++;
+               parse_string(argv[optind-1], stringinfo);
+               if (invert)
+                       stringinfo->invert = 1;
+               *flags = 1;
+               break;
+
+       default:
+               return 0;
+       }
+       return 1;
+}
+
+static void
+print_string(char string[], int invert, int numeric)
+{
+
+       if (invert)
+               fputc('!', stdout);
+       printf("%s ",string);
+}
+
+/* Final check; must have specified --string. */
+static void
+final_check(unsigned int flags)
+{
+       if (!flags)
+               exit_error(PARAMETER_PROBLEM,
+                          "STRING match: You must specify `--string'");
+}
+
+/* Prints out the matchinfo. */
+static void
+print(const struct ipt_ip *ip,
+      const struct ipt_entry_match *match,
+      int numeric)
+{
+       printf("STRING match ");
+       print_string(((struct ipt_string_info *)match->data)->string,
+                 ((struct ipt_string_info *)match->data)->invert, numeric);
+}
+
+/* Saves the union ipt_matchinfo in parsable form to stdout. */
+static void
+save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
+{
+       printf("--tos ");
+       print_string(((struct ipt_string_info *)match->data)->string,
+                 ((struct ipt_string_info *)match->data)->invert, 0);
+}
+
+struct iptables_match string
+= { NULL,
+    "string",
+    NETFILTER_VERSION,
+    IPT_ALIGN(sizeof(struct ipt_string_info)),
+    IPT_ALIGN(sizeof(struct ipt_string_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+       register_match(&string);
+}