Tom Marshall <tommy_at_home.tig-grr.com>
diff --git a/extensions/ebt_limit.c b/extensions/ebt_limit.c
new file mode 100644
index 0000000..02b8f77
--- /dev/null
+++ b/extensions/ebt_limit.c
@@ -0,0 +1,219 @@
+/* Shared library add-on to ebtables to add limit support.
+ *
+ * Swipted from iptables' limit match.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include "../include/ebtables_u.h"
+#include <linux/netfilter_bridge/ebt_limit.h>
+
+#define EBT_LIMIT_AVG "3/hour"
+#define EBT_LIMIT_BURST 5
+
+/* from iptables.c */
+#include <errno.h>
+int
+string_to_number(const char *s, unsigned int min, unsigned int max,
+ unsigned int *ret)
+{
+ long number;
+ char *end;
+
+ /* Handle hex, octal, etc. */
+ errno = 0;
+ number = strtol(s, &end, 0);
+ if (*end == '\0' && end != s) {
+ /* we parsed a number, let's see if we want this */
+ if (errno != ERANGE && min <= number && number <= max) {
+ *ret = number;
+ return 0;
+ }
+ }
+ return -1;
+}
+
+#define FLAG_LIMIT 0x01
+#define FLAG_LIMIT_BURST 0x02
+
+#define ARG_LIMIT '1'
+#define ARG_LIMIT_BURST '2'
+
+static struct option opts[] =
+{
+ { "limit", required_argument, 0, ARG_LIMIT },
+ { "limit-burst", required_argument, 0, ARG_LIMIT_BURST },
+ { 0 }
+};
+
+static void print_help(void)
+{
+ printf(
+"limit options:\n"
+"--limit avg max average match rate: default "EBT_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, -1 < number < 10001,\n"
+" default %u\n"
+"\n", EBT_LIMIT_BURST);
+}
+
+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 > EBT_LIMIT_SCALE)
+ return 0;
+
+ *val = EBT_LIMIT_SCALE * mult / r;
+ return 1;
+}
+
+/* Initialize the match. */
+static void init(struct ebt_entry_match *m)
+{
+ struct ebt_limit_info *r = (struct ebt_limit_info *)m->data;
+
+ parse_rate(EBT_LIMIT_AVG, &r->avg);
+ r->burst = EBT_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");
+*/
+
+static int parse(int c, char **argv, int argc,
+ const struct ebt_u_entry *entry,
+ unsigned int *flags,
+ struct ebt_entry_match **match)
+{
+ struct ebt_limit_info *r = (struct ebt_limit_info *)(*match)->data;
+ unsigned int num;
+
+ switch(c) {
+ case ARG_LIMIT:
+ check_option(flags, FLAG_LIMIT);
+ if (check_inverse(optarg))
+ print_error("Unexpected `!' after --limit");
+ if (!parse_rate(optarg, &r->avg))
+ print_error("bad rate `%s'", optarg);
+ break;
+
+ case ARG_LIMIT_BURST:
+ check_option(flags, FLAG_LIMIT_BURST);
+ if (check_inverse(optarg))
+ print_error("Unexpected `!' after --limit-burst");
+
+ if (string_to_number(optarg, 0, 10000, &num) == -1)
+ print_error("bad --limit-burst `%s'", optarg);
+ r->burst = num;
+ break;
+
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+static void final_check(unsigned int flags)
+{
+ /* empty */
+}
+
+struct rates
+{
+ const char *name;
+ u_int32_t mult;
+};
+
+static struct rates g_rates[] =
+{
+ { "day", EBT_LIMIT_SCALE*24*60*60 },
+ { "hour", EBT_LIMIT_SCALE*60*60 },
+ { "min", EBT_LIMIT_SCALE*60 },
+ { "sec", EBT_LIMIT_SCALE }
+};
+
+static void print_rate(u_int32_t period)
+{
+ unsigned int i;
+
+ for (i = 1; i < sizeof(g_rates)/sizeof(struct rates); i++)
+ if (period > g_rates[i].mult ||
+ g_rates[i].mult/period < g_rates[i].mult%period)
+ break;
+
+ printf("%u/%s ", g_rates[i-1].mult / period, g_rates[i-1].name);
+}
+
+/* Prints out the matchinfo. */
+static void
+print(const struct ebt_u_entry *entry, const struct ebt_entry_match *match)
+{
+ struct ebt_limit_info *r = (struct ebt_limit_info *)match->data;
+
+ printf("limit: avg "); print_rate(r->avg);
+ printf("burst %u ", r->burst);
+}
+
+static int compare(const struct ebt_entry_match* m1, const struct ebt_entry_match *m2)
+{
+ struct ebt_limit_info* li1 = (struct ebt_limit_info*)m1->data;
+ struct ebt_limit_info* li2 = (struct ebt_limit_info*)m2->data;
+
+ if (li1->avg != li2->avg)
+ return 0;
+
+ if (li1->burst != li2->burst)
+ return 0;
+
+ return 1;
+}
+
+static struct ebt_u_match limit_match =
+{
+ .name EBT_LIMIT_MATCH,
+ .size sizeof(struct ebt_limit_info),
+ .help print_help,
+ .init init,
+ .parse parse,
+ .final_check final_check,
+ .print print,
+ .compare compare,
+ .extra_ops opts,
+};
+
+static void _init(void) __attribute((constructor));
+static void _init(void)
+{
+ register_match(&limit_match);
+}