Merge commit 'origin/trunk@12184' into fedora

[iptables.git] / trunk / extensions / libxt_limit.c

diff --git a/trunk/extensions/libxt_limit.c b/trunk/extensions/libxt_limit.c
new file mode 100644 (file)
index 0000000..424635a
--- /dev/null
+++ b/trunk/extensions/libxt_limit.c
@@ -0,0 +1,184 @@
+/* Shared library add-on to iptables to add limit support.
+ *
+ * Jérôme de Vivie   <devivie@info.enserb.u-bordeaux.fr>
+ * Hervé Eychenne    <rv@wallfire.org>
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <xtables.h>
+#include <stddef.h>
+#include <linux/netfilter/x_tables.h>
+/* For 64bit kernel / 32bit userspace */
+#include "../include/linux/netfilter/xt_limit.h"
+
+#define XT_LIMIT_AVG   "3/hour"
+#define XT_LIMIT_BURST 5
+
+/* Function which prints out usage message. */
+static void limit_help(void)
+{
+       printf(
+"limit match options:\n"
+"--limit avg                   max average match rate: default "XT_LIMIT_AVG"\n"
+"                                [Packets per second unless followed by \n"
+"                                /sec /minute /hour /day postfixes]\n"
+"--limit-burst number          number to match in a burst, default %u\n",
+XT_LIMIT_BURST);
+}
+
+static const struct option limit_opts[] = {
+       { "limit", 1, NULL, '%' },
+       { "limit-burst", 1, NULL, '$' },
+       { .name = NULL }
+};
+
+static
+int parse_rate(const char *rate, u_int32_t *val)
+{
+       const char *delim;
+       u_int32_t r;
+       u_int32_t mult = 1;  /* Seconds by default. */
+
+       delim = strchr(rate, '/');
+       if (delim) {
+               if (strlen(delim+1) == 0)
+                       return 0;
+
+               if (strncasecmp(delim+1, "second", strlen(delim+1)) == 0)
+                       mult = 1;
+               else if (strncasecmp(delim+1, "minute", strlen(delim+1)) == 0)
+                       mult = 60;
+               else if (strncasecmp(delim+1, "hour", strlen(delim+1)) == 0)
+                       mult = 60*60;
+               else if (strncasecmp(delim+1, "day", strlen(delim+1)) == 0)
+                       mult = 24*60*60;
+               else
+                       return 0;
+       }
+       r = atoi(rate);
+       if (!r)
+               return 0;
+
+       /* This would get mapped to infinite (1/day is minimum they
+           can specify, so we're ok at that end). */
+       if (r / mult > XT_LIMIT_SCALE)
+               exit_error(PARAMETER_PROBLEM, "Rate too fast `%s'\n", rate);
+
+       *val = XT_LIMIT_SCALE * mult / r;
+       return 1;
+}
+
+/* Initialize the match. */
+static void limit_init(struct xt_entry_match *m)
+{
+       struct xt_rateinfo *r = (struct xt_rateinfo *)m->data;
+
+       parse_rate(XT_LIMIT_AVG, &r->avg);
+       r->burst = XT_LIMIT_BURST;
+
+}
+
+/* FIXME: handle overflow:
+       if (r->avg*r->burst/r->burst != r->avg)
+               exit_error(PARAMETER_PROBLEM,
+                          "Sorry: burst too large for that avg rate.\n");
+*/
+
+/* Function which parses command options; returns true if it
+   ate an option */
+static int
+limit_parse(int c, char **argv, int invert, unsigned int *flags,
+            const void *entry, struct xt_entry_match **match)
+{
+       struct xt_rateinfo *r = (struct xt_rateinfo *)(*match)->data;
+       unsigned int num;
+
+       switch(c) {
+       case '%':
+               if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
+               if (!parse_rate(optarg, &r->avg))
+                       exit_error(PARAMETER_PROBLEM,
+                                  "bad rate `%s'", optarg);
+               break;
+
+       case '$':
+               if (check_inverse(argv[optind-1], &invert, &optind, 0)) break;
+               if (string_to_number(optarg, 0, 10000, &num) == -1)
+                       exit_error(PARAMETER_PROBLEM,
+                                  "bad --limit-burst `%s'", optarg);
+               r->burst = num;
+               break;
+
+       default:
+               return 0;
+       }
+
+       if (invert)
+               exit_error(PARAMETER_PROBLEM,
+                          "limit does not support invert");
+
+       return 1;
+}
+
+static const struct rates
+{
+       const char *name;
+       u_int32_t mult;
+} rates[] = { { "day", XT_LIMIT_SCALE*24*60*60 },
+             { "hour", XT_LIMIT_SCALE*60*60 },
+             { "min", XT_LIMIT_SCALE*60 },
+             { "sec", XT_LIMIT_SCALE } };
+
+static void print_rate(u_int32_t period)
+{
+       unsigned int i;
+
+       for (i = 1; i < sizeof(rates)/sizeof(struct rates); i++) {
+               if (period > rates[i].mult
+            || rates[i].mult/period < rates[i].mult%period)
+                       break;
+       }
+
+       printf("%u/%s ", rates[i-1].mult / period, rates[i-1].name);
+}
+
+/* Prints out the matchinfo. */
+static void
+limit_print(const void *ip, const struct xt_entry_match *match, int numeric)
+{
+       struct xt_rateinfo *r = (struct xt_rateinfo *)match->data;
+       printf("limit: avg "); print_rate(r->avg);
+       printf("burst %u ", r->burst);
+}
+
+/* FIXME: Make minimalist: only print rate if not default --RR */
+static void limit_save(const void *ip, const struct xt_entry_match *match)
+{
+       struct xt_rateinfo *r = (struct xt_rateinfo *)match->data;
+
+       printf("--limit "); print_rate(r->avg);
+       if (r->burst != XT_LIMIT_BURST)
+               printf("--limit-burst %u ", r->burst);
+}
+
+static struct xtables_match limit_match = {
+       .family         = AF_UNSPEC,
+       .name           = "limit",
+       .version        = XTABLES_VERSION,
+       .size           = XT_ALIGN(sizeof(struct xt_rateinfo)),
+       .userspacesize  = offsetof(struct xt_rateinfo, prev),
+       .help           = limit_help,
+       .init           = limit_init,
+       .parse          = limit_parse,
+       .print          = limit_print,
+       .save           = limit_save,
+       .extra_opts     = limit_opts,
+};
+
+void _init(void)
+{
+       xtables_register_match(&limit_match);
+}