summaryrefslogtreecommitdiffstats
path: root/extensions/libxt_u32.c
diff options
context:
space:
mode:
authorJan Engelhardt <jengelh@medozas.de>2007-09-10 11:50:46 +0000
committerPatrick McHardy <kaber@trash.net>2007-09-10 11:50:46 +0000
commit9640e529bd08c4c0458246fae0fd6b473c94ab46 (patch)
treecfffe7b11850caff98b483f62afbf896d24fd2e8 /extensions/libxt_u32.c
parent97fb2f1579f0794377db1dca7c5bb07fade1a0dc (diff)
Adds u32 to iptables.
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Diffstat (limited to 'extensions/libxt_u32.c')
-rw-r--r--extensions/libxt_u32.c307
1 files changed, 307 insertions, 0 deletions
diff --git a/extensions/libxt_u32.c b/extensions/libxt_u32.c
new file mode 100644
index 00000000..e2642f39
--- /dev/null
+++ b/extensions/libxt_u32.c
@@ -0,0 +1,307 @@
+/* Shared library add-on to iptables to add u32 matching,
+ * generalized matching on values found at packet offsets
+ *
+ * Detailed doc is in the kernel module source
+ * net/netfilter/xt_u32.c
+ *
+ * (C) 2002 by Don Cohen <don-netf@isis.cs3-inc.com>
+ * Copyright Jan Engelhardt <jengelh@gmx.de>, 2007
+ * Released under the terms of GNU GPL v2
+ */
+#include <sys/types.h>
+#include <ctype.h>
+#include <errno.h>
+#include <getopt.h>
+#include <netdb.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <xtables.h>
+#include "../include/linux/netfilter/xt_u32.h"
+
+static const struct option u32_opts[] = {
+ {"u32", 1, NULL, 'u'},
+ {NULL},
+};
+
+static void u32_help(void)
+{
+ printf(
+ "u32 v%s options:\n"
+ "[!] --u32 tests\n"
+ "\t\t""tests := location \"=\" value | tests \"&&\" location \"=\" value\n"
+ "\t\t""value := range | value \",\" range\n"
+ "\t\t""range := number | number \":\" number\n"
+ "\t\t""location := number | location operator number\n"
+ "\t\t""operator := \"&\" | \"<<\" | \">>\" | \"@\"\n",
+ IPTABLES_VERSION);
+ return;
+}
+
+static void u32_dump(const struct xt_u32 *data)
+{
+ const struct xt_u32_test *ct;
+ unsigned int testind, i;
+
+ for (testind = 0; testind < data->ntests; ++testind) {
+ ct = &data->tests[testind];
+
+ if (testind > 0)
+ printf("&&");
+
+ printf("0x%x", ct->location[0].number);
+ for (i = 1; i < ct->nnums; ++i) {
+ switch (ct->location[i].nextop) {
+ case XT_U32_AND:
+ printf("&");
+ break;
+ case XT_U32_LEFTSH:
+ printf("<<");
+ break;
+ case XT_U32_RIGHTSH:
+ printf(">>");
+ break;
+ case XT_U32_AT:
+ printf("@");
+ break;
+ }
+ printf("0x%x", ct->location[i].number);
+ }
+
+ printf("=");
+ for (i = 0; i < ct->nvalues; ++i) {
+ if (i > 0)
+ printf(",");
+ if (ct->value[i].min == ct->value[i].max)
+ printf("0x%x", ct->value[i].min);
+ else
+ printf("0x%x:0x%x", ct->value[i].min,
+ ct->value[i].max);
+ }
+ }
+ printf(" ");
+}
+
+/* string_to_number() is not quite what we need here ... */
+static u_int32_t parse_number(char **s, int pos)
+{
+ u_int32_t number;
+ char *end;
+
+ errno = 0;
+ number = strtoul(*s, &end, 0);
+ if (end == *s)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %d: expected number", pos);
+ if (errno != 0)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %d: error reading number", pos);
+ *s = end;
+ return number;
+}
+
+/* Function which parses command options; returns true if it ate an option */
+static int u32_parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry, struct xt_entry_match **match)
+{
+ struct xt_u32 *data = (void *)(*match)->data;
+ unsigned int testind = 0, locind = 0, valind = 0;
+ struct xt_u32_test *ct = &data->tests[testind]; /* current test */
+ char *arg = argv[optind-1]; /* the argument string */
+ char *start = arg;
+ int state = 0;
+
+ if (c != 'u')
+ return 0;
+
+ data->invert = invert;
+
+ /*
+ * states:
+ * 0 = looking for numbers and operations,
+ * 1 = looking for ranges
+ */
+ while (1) {
+ /* read next operand/number or range */
+ while (isspace(*arg))
+ ++arg;
+
+ if (*arg == '\0') {
+ /* end of argument found */
+ if (state == 0)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: abrupt end of input after location specifier");
+ if (valind == 0)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: test ended with no value specified");
+
+ ct->nnums = locind;
+ ct->nvalues = valind;
+ data->ntests = ++testind;
+
+ if (testind > XT_U32_MAXSIZE)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: too many \"&&\"s",
+ arg - start);
+ return 1;
+ }
+
+ if (state == 0) {
+ /*
+ * reading location: read a number if nothing read yet,
+ * otherwise either op number or = to end location spec
+ */
+ if (*arg == '=') {
+ if (locind == 0) {
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: "
+ "location spec missing",
+ arg - start);
+ } else {
+ ++arg;
+ state = 1;
+ }
+ } else {
+ if (locind != 0) {
+ /* need op before number */
+ if (*arg == '&') {
+ ct->location[locind].nextop = XT_U32_AND;
+ } else if (*arg == '<') {
+ if (*++arg != '<')
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: a second < expected", arg - start);
+ ct->location[locind].nextop = XT_U32_LEFTSH;
+ } else if (*arg == '>') {
+ if (*++arg != '>')
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: a second > expected", arg - start);
+ ct->location[locind].nextop = XT_U32_RIGHTSH;
+ } else if (*arg == '@') {
+ ct->location[locind].nextop = XT_U32_AT;
+ } else {
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: operator expected", arg - start);
+ }
+ ++arg;
+ }
+ /* now a number; string_to_number skips white space? */
+ ct->location[locind].number =
+ parse_number(&arg, arg - start);
+ if (++locind > XT_U32_MAXSIZE)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: too many operators", arg - start);
+ }
+ } else {
+ /*
+ * state 1 - reading values: read a range if nothing
+ * read yet, otherwise either ,range or && to end
+ * test spec
+ */
+ if (*arg == '&') {
+ if (*++arg != '&')
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: a second & was expected", arg - start);
+ if (valind == 0) {
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: value spec missing", arg - start);
+ } else {
+ ct->nnums = locind;
+ ct->nvalues = valind;
+ ct = &data->tests[++testind];
+ if (testind > XT_U32_MAXSIZE)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: too many \"&&\"s", arg - start);
+ ++arg;
+ state = 0;
+ locind = 0;
+ valind = 0;
+ }
+ } else { /* read value range */
+ if (valind > 0) { /* need , before number */
+ if (*arg != ',')
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: expected , or &&", arg - start);
+ ++arg;
+ }
+ ct->value[valind].min =
+ parse_number(&arg, arg - start);
+
+ while (isspace(*arg))
+ ++arg;
+
+ if (*arg == ':') {
+ ++arg;
+ ct->value[valind].max =
+ parse_number(&arg, arg-start);
+ } else {
+ ct->value[valind].max =
+ ct->value[valind].min;
+ }
+
+ if (++valind > XT_U32_MAXSIZE)
+ exit_error(PARAMETER_PROBLEM,
+ "u32: at char %ld: too many \",\"s", arg - start);
+ }
+ }
+ }
+}
+
+static void u32_check(unsigned int flags)
+{
+}
+
+static void u32_print(const void *ip, const struct xt_entry_match *match,
+ int numeric)
+{
+ const struct xt_u32 *data = (const void *)match->data;
+ printf("u32 ");
+ if (data->invert)
+ printf("! ");
+ u32_dump(data);
+ return;
+}
+
+static void u32_save(const void *ip, const struct xt_entry_match *match)
+{
+ const struct xt_u32 *data = (const void *)match->data;
+ if (data->invert)
+ printf("! ");
+ printf("--u32 ");
+ u32_dump(data);
+ return;
+}
+
+static struct xtables_match u32_reg = {
+ .name = "u32",
+ .version = IPTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_u32)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_u32)),
+ .help = u32_help,
+ .parse = u32_parse,
+ .final_check = u32_check,
+ .print = u32_print,
+ .save = u32_save,
+ .extra_opts = u32_opts,
+};
+
+static struct xtables_match u32_reg6 = {
+ .name = "u32",
+ .family = AF_INET6,
+ .version = IPTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_u32)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_u32)),
+ .help = u32_help,
+ .parse = u32_parse,
+ .final_check = u32_check,
+ .print = u32_print,
+ .save = u32_save,
+ .extra_opts = u32_opts,
+};
+
+void _init(void)
+{
+ xtables_register_match(&u32_reg);
+ xtables_register_match(&u32_reg6);
+ return;
+}