add dstlimit extension (kernel code in patch-o-matic soon)

2 files changed, 308 insertions, 0 deletions

diff --git a/extensions/.dstlimit-test b/extensions/.dstlimit-test
new file mode 100755
index 0000000..b7c8ef9
--- /dev/null
+++ b/extensions/.dstlimit-test
@@ -0,0 +1,2 @@
+#! /bin/sh
+[ -f $KERNEL_DIR/net/ipv4/netfilter/ipt_dstlimit.c ] && echo dstlimit
diff --git a/extensions/libipt_dstlimit.c b/extensions/libipt_dstlimit.c
new file mode 100644
index 0000000..225da4d
--- /dev/null
+++ b/extensions/libipt_dstlimit.c
@@ -0,0 +1,306 @@
+/* iptables match extension for limiting packets per destination
+ *
+ * (C) 2003 by Harald Welte <laforge@netfilter.org>
+ *
+ * Development of this code was funded by Astaro AG, http://www.astaro.com/
+ *
+ * Based on ipt_limit.c by
+ * Jérôme de Vivie   <devivie@info.enserb.u-bordeaux.fr>
+ * Hervé Eychenne    <rv@wallfire.org>
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <iptables.h>
+#include <stddef.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_dstlimit.h>
+
+#define IPT_DSTLIMIT_BURST	5
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"dstlimit v%s options:\n"
+"--dstlimit <avg>		max average match rate\n"
+"                                [Packets per second unless followed by \n"
+"                                /sec /minute /hour /day postfixes]\n"
+"--dstlimit-mode <mode>		mode (destip|destip-destport)\n"
+"[--dstlimit-burst <num>]	number to match in a burst, default %u\n"
+"[--dstlimit-htable-size <num>]	number of hashtable buckets\n"
+"[--dstlimit-htable-max <num>]	number of hashtable entries\n"
+"[--dstlimit-htable-gcinterval]	interval between garbage collection runs\n"
+"[--dstlimit-htable-expire]	after which time are idle entries expired?\n"
+"\n", IPTABLES_VERSION, IPT_DSTLIMIT_BURST);
+}
+
+static struct option opts[] = {
+	{ "dstlimit", 1, 0, '%' },
+	{ "dstlimit-burst", 1, 0, '$' },
+	{ "dstlimit-htable-size", 1, 0, '&' },
+	{ "dstlimit-htable-max", 1, 0, '*' },
+	{ "dstlimit-htable-gcinterval", 1, 0, '(' },
+	{ "dstlimit-htable-expire", 1, 0, ')' },
+	{ "dstlimit-mode", 1, 0, '_' },
+	{ 0 }
+};
+
+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 > IPT_DSTLIMIT_SCALE)
+		exit_error(PARAMETER_PROBLEM, "Rate too fast `%s'\n", rate);
+
+	*val = IPT_DSTLIMIT_SCALE * mult / r;
+	return 1;
+}
+
+/* Initialize the match. */
+static void
+init(struct ipt_entry_match *m, unsigned int *nfcache)
+{
+	struct ipt_dstlimit_info *r = (struct ipt_dstlimit_info *)m->data;
+
+	r->burst = IPT_DSTLIMIT_BURST;
+
+	/* Can't cache this */
+	*nfcache |= NFC_UNKNOWN;
+}
+
+#define PARAM_LIMIT		0x00000001
+#define PARAM_BURST		0x00000002
+#define PARAM_MODE		0x00000004
+#define PARAM_SIZE		0x00000010
+#define PARAM_MAX		0x00000020
+#define PARAM_GCINTERVAL	0x00000040
+#define PARAM_EXPIRE		0x00000080
+
+/* 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_dstlimit_info *r = 
+			(struct ipt_dstlimit_info *)(*match)->data;
+	unsigned int num;
+
+	switch(c) {
+	case '%':
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM,
+				   "Unexpected `!' after --dstlimit");
+		if (!parse_rate(optarg, &r->avg))
+			exit_error(PARAMETER_PROBLEM,
+				   "bad rate `%s'", optarg);
+		*flags |= PARAM_LIMIT;
+		break;
+
+	case '$':
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM,
+				   "Unexpected `!' after --dstlimit-burst");
+
+		if (string_to_number(optarg, 0, 10000, &num) == -1)
+			exit_error(PARAMETER_PROBLEM,
+				   "bad --dstlimit-burst `%s'", optarg);
+		r->burst = num;
+		*flags |= PARAM_BURST;
+		break;
+	case '&':
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM,
+				"Unexpected `!' after --dstlimit-htable-size");
+
+		if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
+			exit_error(PARAMETER_PROBLEM,
+				"bad --dstlimit-htable-size: `%s'", optarg);
+		r->hinfo.size = num;
+		*flags |= PARAM_SIZE;
+		break;
+	case '*':
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM,
+				"Unexpected `!' after --dstlimit-htable-max");
+		if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
+			exit_error(PARAMETER_PROBLEM,
+				"bad --dstlimit-htable-max: `%s'", optarg);
+		r->hinfo.max = num;
+		*flags |= PARAM_MAX;
+		break;
+	case '(':
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM, "Unexpected `!' after "
+					"--dstlimit-htable-gcinterval");
+		if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
+			exit_error(PARAMETER_PROBLEM,
+				"bad --dstlimit-htable-gcinterval: `%s'", 
+				optarg);
+		/* FIXME: not HZ dependent!! */
+		r->hinfo.gc_interval = num;
+		*flags |= PARAM_GCINTERVAL;
+		break;
+	case ')':
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM, "Unexpected `!' after " 
+					"--dstlimit-htable-expire");
+		if (string_to_number(optarg, 0, 0xffffffff, &num) == -1)
+			exit_error(PARAMETER_PROBLEM,
+				"bad --dstlimit-htable-expire: `%s'", optarg);
+		/* FIXME: not HZ dependent */
+		r->hinfo.expire = num;
+		*flags |= PARAM_EXPIRE;
+		break;
+	case '_':
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM, "Unexpected `!' after "
+					"--dstlimit-mode");
+		if (!strcmp(optarg, "destip"))
+			r->mode = IPT_DSTLIMIT_MODE_DIP;
+		else if (!strcmp(optarg, "destip-destport"))
+			r->mode = IPT_DSTLIMIT_MODE_DIP_DPT;
+		else
+			exit_error(PARAMETER_PROBLEM, 
+				"bad --dstlimit-mode: `%s'\n", optarg);
+		*flags |= PARAM_MODE;
+		break;
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+/* Final check; nothing. */
+static void final_check(unsigned int flags)
+{
+	if (!(flags & PARAM_LIMIT))
+		exit_error(PARAMETER_PROBLEM,
+				"You have to specify --dstlimit-rate");
+	if (!(flags & PARAM_MODE))
+		exit_error(PARAMETER_PROBLEM,
+				"You have to specify --dstlimit-mode");
+}
+
+static struct rates
+{
+	const char *name;
+	u_int32_t mult;
+} rates[] = { { "day", IPT_DSTLIMIT_SCALE*24*60*60 },
+	      { "hour", IPT_DSTLIMIT_SCALE*60*60 },
+	      { "min", IPT_DSTLIMIT_SCALE*60 },
+	      { "sec", IPT_DSTLIMIT_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
+print(const struct ipt_ip *ip,
+      const struct ipt_entry_match *match,
+      int numeric)
+{
+	struct ipt_dstlimit_info *r = 
+		(struct ipt_dstlimit_info *)match->data;
+	printf("limit: avg "); print_rate(r->avg);
+	printf("burst %u ", r->burst);
+	switch (r->mode) {
+		case IPT_DSTLIMIT_MODE_DIP:
+			printf("mode dstip ");
+			break;
+		case IPT_DSTLIMIT_MODE_DIP_DPT:
+			printf("mode dstip-dstport ");
+			break;
+	}
+	printf("htable-size %u ", r->hinfo.size);
+	printf("htable-max %u ", r->hinfo.max);
+	printf("htable-gcinterval %u ", r->hinfo.gc_interval);
+	printf("htable-expire %u ", r->hinfo.expire);
+}
+
+/* FIXME: Make minimalist: only print rate if not default --RR */
+static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
+{
+	struct ipt_dstlimit_info *r = 
+		(struct ipt_dstlimit_info *)match->data;
+
+	printf("--limit "); print_rate(r->avg);
+	if (r->burst != IPT_DSTLIMIT_BURST)
+		printf("--limit-burst %u ", r->burst);
+	switch (r->mode) {
+		case IPT_DSTLIMIT_MODE_DIP:
+			printf("--mode dstip ");
+			break;
+		case IPT_DSTLIMIT_MODE_DIP_DPT:
+			printf("--mode dstip-dstport ");
+			break;
+	}
+	printf("--htable-size %u ", r->hinfo.size);
+	printf("--htable-max %u ", r->hinfo.max);
+	printf("--htable-gcinterval %u", r->hinfo.gc_interval);
+	printf("--htable-expire %u ", r->hinfo.expire);
+}
+
+static
+struct iptables_match dstlimit
+= { NULL,
+    "dstlimit",
+    IPTABLES_VERSION,
+    IPT_ALIGN(sizeof(struct ipt_dstlimit_info)),
+    IPT_ALIGN(sizeof(struct ipt_dstlimit_info)),
+    //offsetof(struct ipt_dstlimit_info, prev),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+	register_match(&dstlimit);
+}