Netfilter target: CLASSIFY (was Re: [LARTC] QoS in Linux: Project

[Patrick McHardy <kaber@trash.net>]

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Patrick McHardy wrote:

> Chris Wilson wrote:
>
>>
>> My proposed solution is a new Netfilter table which packets pass through
>> on their way out to a device.There would be just a single terminal 
>> target,
>> CLASSIFY, which would enqueue the packet in the specified classifier.
>> Unclassified packets which drop off the end of the entry chain would 
>> pass
>> on to the old-style tc filtering system, for backwards compatibility.
>>
>
> i think with netfilter table you mean iptables table. iptables can 
> only see ip, so you still
> have the need for tc filters as they exist. The classify target can 
> easily be made,
> just set skb->priority to the class id and the qdisc will take care of 
> the rest. if your company
> wishes to sponsor me for writing one for you, go ahead ;)

sorry if my last mail sounded arrogant, i think you deserve honour for 
beeing willing to sponsor linux QoS development.
As sign of my appologies, take this CLASSIFY target patch against latest 
netfiler CVS ;) It is untested, but despite possible
easy-to-fix typos i hope it works. chmod +x 
userspace/extensions/.CLASSIFY-test after applying the patch.
Usage is:
-j CLASSIFY --set-class MAJOR:MINOR

Bye,
Patrick







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diff -urN netfilter-clean/patch-o-matic/extra/CLASSIFY.patch netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch
--- netfilter-clean/patch-o-matic/extra/CLASSIFY.patch	1970-01-01 01:00:00.000000000 +0100
+++ netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch	2003-01-25 02:41:19.000000000 +0100
@@ -0,0 +1,83 @@
+diff -urN linux-2.4.20-clean/include/linux/netfilter_ipv4/ipt_CLASSIFY.h linux-2.4.20_nfclassify/include/linux/netfilter_ipv4/ipt_CLASSIFY.h
+--- linux-2.4.20-clean/include/linux/netfilter_ipv4/ipt_CLASSIFY.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.4.20_nfclassify/include/linux/netfilter_ipv4/ipt_CLASSIFY.h	2003-01-25 02:11:35.000000000 +0100
+@@ -0,0 +1,8 @@
++#ifndef _IPT_CLASSIFY_H
++#define _IPT_CLASSIFY_H
++
++struct ipt_classify_target_info {
++	unsigned int priority;
++};
++
++#endif /*_IPT_CLASSIFY_H */
+diff -urN linux-2.4.20-clean/net/ipv4/netfilter/ipt_CLASSIFY.c linux-2.4.20_nfclassify/net/ipv4/netfilter/ipt_CLASSIFY.c
+--- linux-2.4.20-clean/net/ipv4/netfilter/ipt_CLASSIFY.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.4.20_nfclassify/net/ipv4/netfilter/ipt_CLASSIFY.c	2003-01-25 02:09:36.000000000 +0100
+@@ -0,0 +1,67 @@
++/* This is a module which is used for setting the skb->priority field of an skb for qdisc classification. */
++#include <linux/module.h>
++#include <linux/skbuff.h>
++#include <linux/ip.h>
++#include <net/checksum.h>
++
++#include <linux/netfilter_ipv4/ip_tables.h>
++#include <linux/netfilter_ipv4/ipt_CLASSIFY.h>
++
++static unsigned int
++target(struct sk_buff **pskb,
++       unsigned int hooknum,
++       const struct net_device *in,
++       const struct net_device *out,
++       const void *targinfo,
++       void *userinfo)
++{
++	const struct ipt_classify_target_info *clinfo = targinfo;
++
++	if((*pskb)->priority != clinfo->priority) {
++		(*pskb)->priority = clinfo->priority;
++		(*pskb)->nfcache |= NFC_ALTERED;
++	}
++	return IPT_CONTINUE;
++}
++
++static int
++checkentry(const char *tablename,
++	   const struct ipt_entry *e,
++           void *targinfo,
++           unsigned int targinfosize,
++           unsigned int hook_mask)
++{
++	if (targinfosize != IPT_ALIGN(sizeof(struct ipt_classify_target_info))) {
++		printk(KERN_WARNING "MARK: targinfosize %u != %Zu\n",
++		       targinfosize,
++		       IPT_ALIGN(sizeof(struct ipt_classify_target_info)));
++		return 0;
++	}
++
++	if (strcmp(tablename, "mangle") != 0) {
++		printk(KERN_WARNING "CLASSIFY: can only be called from \"mangle\" table, not \"%s\"\n", tablename);
++		return 0;
++	}
++
++	return 1;
++}
++
++static struct ipt_target ipt_classify_reg
++= { { NULL, NULL }, "CLASSIFY", target, checkentry, NULL, THIS_MODULE };
++
++static int __init init(void)
++{
++	if (ipt_register_target(&ipt_classify_reg))
++		return -EINVAL;
++
++	return 0;
++}
++
++static void __exit fini(void)
++{
++	ipt_unregister_target(&ipt_classify_reg);
++}
++
++module_init(init);
++module_exit(fini);
++MODULE_LICENSE("GPL");
diff -urN netfilter-clean/patch-o-matic/extra/CLASSIFY.patch.config.in netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch.config.in
--- netfilter-clean/patch-o-matic/extra/CLASSIFY.patch.config.in	1970-01-01 01:00:00.000000000 +0100
+++ netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch.config.in	2003-01-25 02:45:03.000000000 +0100
@@ -0,0 +1,2 @@
+      dep_tristate '    MIRROR target support (EXPERIMENTAL)' CONFIG_IP_NF_TARGET_MIRROR $CONFIG_IP_NF_FILTER
+      dep_tristate '    CLASSIFY target support (EXPERIMENTAL)' CONFIG_IP_NF_TARGET_CLASSIFY $CONFIG_IP_NF_FILTER
diff -urN netfilter-clean/patch-o-matic/extra/CLASSIFY.patch.help netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch.help
--- netfilter-clean/patch-o-matic/extra/CLASSIFY.patch.help	1970-01-01 01:00:00.000000000 +0100
+++ netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch.help	2003-01-25 02:42:39.000000000 +0100
@@ -0,0 +1,5 @@
+Author: Patrick McHardy <kaber@trash.net>
+Status: untested
+
+This patch adds support for the CLASSIFY target which sets skb->priority.
+Some qdiscs can use this value for classifying packets.
diff -urN netfilter-clean/patch-o-matic/extra/CLASSIFY.patch.makefile netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch.makefile
--- netfilter-clean/patch-o-matic/extra/CLASSIFY.patch.makefile	1970-01-01 01:00:00.000000000 +0100
+++ netfilter_nfclassify/patch-o-matic/extra/CLASSIFY.patch.makefile	2003-01-25 02:44:26.000000000 +0100
@@ -0,0 +1,2 @@
+obj-$(CONFIG_IP_NF_TARGET_MIRROR) += ipt_MIRROR.o
+obj-$(CONFIG_IP_NF_TARGET_CLASSIFY) += ipt_CLASSIFY.o
diff -urN netfilter-clean/userspace/extensions/.CLASSIFY-test netfilter_nfclassify/userspace/extensions/.CLASSIFY-test
--- netfilter-clean/userspace/extensions/.CLASSIFY-test	1970-01-01 01:00:00.000000000 +0100
+++ netfilter_nfclassify/userspace/extensions/.CLASSIFY-test	2003-01-25 02:40:41.000000000 +0100
@@ -0,0 +1,3 @@
+#! /bin/sh
+[ -f $KERNEL_DIR/net/ipv4/netfilter/ipt_CLASSIFY.c ] && echo CLASSIFY
+
diff -urN netfilter-clean/userspace/extensions/libipt_CLASSIFY.c netfilter_nfclassify/userspace/extensions/libipt_CLASSIFY.c
--- netfilter-clean/userspace/extensions/libipt_CLASSIFY.c	1970-01-01 01:00:00.000000000 +0100
+++ netfilter_nfclassify/userspace/extensions/libipt_CLASSIFY.c	2003-01-25 02:40:00.000000000 +0100
@@ -0,0 +1,125 @@
+/* Shared library add-on to iptables to add CLASSIFY target support. */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_CLASSIFY.h>
+#include <linux/pkt_sched.h>
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"CLASSIFY target v%s options:\n"
+"  --set-class [MAJOR:MINOR]    Set skb->priority value\n"
+"\n",
+IPTABLES_VERSION);
+}
+
+static struct option opts[] = {
+	{ "set-class", 1, 0, '1' },
+	{ 0 }
+};
+
+/* Initialize the target. */
+static void
+init(struct ipt_entry_target *t, unsigned int *nfcache)
+{
+}
+
+unsigned int string_to_priority(const unsigned char *s)
+{
+	char *t;
+
+	if ((t = strstr(s, ":")) == NULL)
+		return atoi(s);
+	*t = '\0';
+	return TC_H_MAKE(atoi(s) << 16, atoi(t+1));
+}
+
+/* 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,
+      struct ipt_entry_target **target)
+{
+	struct ipt_classify_target_info *clinfo
+		= (struct ipt_classify_target_info *)(*target)->data;
+
+	switch (c) {
+	case '1':
+		clinfo->priority = string_to_priority(optarg);
+		if (*flags)
+			exit_error(PARAMETER_PROBLEM,
+			           "CLASSIFY: Can't specify --set-class twice");
+		*flags = 1;
+		break;
+
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+static void
+final_check(unsigned int flags)
+{
+	if (!flags)
+		exit_error(PARAMETER_PROBLEM,
+		           "CLASSIFY: Parameter --set-class is required");
+}
+
+static void
+print_class(unsigned int priority, int numeric)
+{
+	printf("%.4x:%.4x ", TC_H_MAJ(priority)>>16, TC_H_MIN(priority));
+}
+
+/* Prints out the targinfo. */
+static void
+print(const struct ipt_ip *ip,
+      const struct ipt_entry_target *target,
+      int numeric)
+{
+	const struct ipt_classify_target_info *clinfo =
+		(const struct ipt_classify_target_info *)target->data;
+	printf("CLASSIFY set ");
+	print_class(clinfo->priority, numeric);
+}
+
+/* Saves the union ipt_targinfo in parsable form to stdout. */
+static void
+save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
+{
+	const struct ipt_classify_target_info *clinfo =
+		(const struct ipt_classify_target_info *)target->data;
+
+	printf("--set-class %.4x:%.4x ", TC_H_MAJ(priority)>>16, TC_H_MIN(priority));
+}
+
+static
+struct iptables_target classify
+= { NULL,
+    "CLASSIFY",
+    IPTABLES_VERSION,
+    IPT_ALIGN(sizeof(struct ipt_classify_target_info)),
+    IPT_ALIGN(sizeof(struct ipt_classify_target_info)),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+	register_target(&classify);
+}