[PKT_SCHED]: Add generic packet editor.

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/tc_act/tc_pedit.h

+#ifndef __LINUX_TC_PED_H
+#define __LINUX_TC_PED_H
+
+#include <linux/pkt_cls.h>
+
+#define TCA_ACT_PEDIT 7
+
+enum
+{
+	TCA_PEDIT_UNSPEC,
+	TCA_PEDIT_TM,
+	TCA_PEDIT_PARMS,
+	__TCA_PEDIT_MAX
+};
+#define TCA_PEDIT_MAX (__TCA_PEDIT_MAX - 1)
+                                                                                
+struct tc_pedit_key
+{
+	__u32           mask;  /* AND */
+	__u32           val;   /*XOR */
+	__u32           off;  /*offset */
+	__u32           at;
+	__u32           offmask;
+	__u32           shift;
+};
+                                                                                
+struct tc_pedit_sel
+{
+	tc_gen;
+	unsigned char           nkeys;
+	unsigned char           flags;
+	struct tc_pedit_key     keys[0];
+};
+#define tc_pedit tc_pedit_sel
+
+#endif

include/net/tc_act/tc_pedit.h

+#ifndef __NET_TC_PED_H
+#define __NET_TC_PED_H
+
+#include <net/pkt_sched.h>
+
+struct tcf_pedit
+{
+	tca_gen(pedit);
+	unsigned char           nkeys;
+	unsigned char           flags;
+	struct tc_pedit_key     keys[0];
+};
+
+#endif

net/sched/Kconfig

@@ -406,3 +406,10 @@ config NET_ACT_MIRRED
         ---help---
         requires new iproute2
         This allows packets to be mirrored or redirected to netdevices
+
+config NET_ACT_PEDIT
+        tristate "Generic Packet Editor Actions"
+        depends on NET_CLS_ACT
+        ---help---
+        requires new iproute2
+        This allows for packets to be generically edited

net/sched/Makefile

@@ -12,6 +12,7 @@ obj-$(CONFIG_NET_ACT_POLICE)	+= police.o
 obj-$(CONFIG_NET_CLS_POLICE)	+= police.o
 obj-$(CONFIG_NET_ACT_GACT)      += gact.o
 obj-$(CONFIG_NET_ACT_MIRRED)    += mirred.o
+obj-$(CONFIG_NET_ACT_PEDIT)     += pedit.o
 obj-$(CONFIG_NET_SCH_CBQ)	+= sch_cbq.o
 obj-$(CONFIG_NET_SCH_HTB)	+= sch_htb.o
 obj-$(CONFIG_NET_SCH_HPFQ)	+= sch_hpfq.o

net/sched/pedit.c

+/*
+ * net/sched/pedit.c	Generic packet editor
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Authors:	Jamal Hadi Salim (2002-4)
+ */
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/bitops.h>
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/in.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <net/sock.h>
+#include <net/pkt_sched.h>
+#include <linux/tc_act/tc_pedit.h>
+#include <net/tc_act/tc_pedit.h>
+
+
+#define PEDIT_DEB 1
+
+/* use generic hash table */
+#define MY_TAB_SIZE     16
+#define MY_TAB_MASK     15
+static u32 idx_gen;
+static struct tcf_pedit *tcf_pedit_ht[MY_TAB_SIZE];
+static rwlock_t pedit_lock = RW_LOCK_UNLOCKED;
+
+#define tcf_st  tcf_pedit
+#define tc_st  tc_pedit
+#define tcf_t_lock   pedit_lock
+#define tcf_ht tcf_pedit_ht
+
+#define CONFIG_NET_ACT_INIT 1
+#include <net/pkt_act.h>
+
+
+int
+tcf_pedit_init(struct rtattr *rta, struct rtattr *est, struct tc_action *a,int ovr, int bind)
+{
+	struct rtattr *tb[TCA_PEDIT_MAX];
+	struct tc_pedit *parm;
+	int size = 0;
+	int ret = 0;
+	struct tcf_pedit *p = NULL;
+
+	if (rtattr_parse(tb, TCA_PEDIT_MAX, RTA_DATA(rta), RTA_PAYLOAD(rta)) < 0)
+		return -1;
+
+	if (NULL == a || NULL == tb[TCA_PEDIT_PARMS - 1]) {
+		printk("BUG: tcf_pedit_init called with NULL params\n");
+		return -1;
+	}
+
+	parm = RTA_DATA(tb[TCA_PEDIT_PARMS - 1]);
+
+	p = tcf_hash_check(parm, a, ovr, bind);
+
+	if (NULL == p) { /* new */
+
+		if (!parm->nkeys)
+			return -1;
+
+		size = sizeof (*p)+ (parm->nkeys*sizeof(struct tc_pedit_key));
+
+		p = tcf_hash_create(parm,est,a,size,ovr,bind);
+
+		if (NULL == p)
+			return -1;
+		ret = 1;
+		goto override;
+	} 
+
+	if (ovr) {
+override:
+		p->flags = parm->flags;
+		p->nkeys = parm->nkeys;
+		p->action = parm->action;
+		memcpy(p->keys,parm->keys,parm->nkeys*(sizeof(struct tc_pedit_key)));
+	}
+
+	return ret;
+}
+
+int
+tcf_pedit_cleanup(struct tc_action *a, int bind)
+{
+	struct tcf_pedit *p;
+	p = PRIV(a,pedit);
+	if (NULL != p)
+		return	tcf_hash_release(p, bind);
+	return 0;
+}
+
+/*
+**
+*/
+int
+tcf_pedit(struct sk_buff **pskb, struct tc_action *a)
+{
+	struct tcf_pedit *p;
+	struct sk_buff *skb = *pskb;
+	int i, munged = 0;
+	u8 *pptr;
+
+	p = PRIV(a,pedit);
+
+	if (NULL == p) {
+		printk("BUG: tcf_pedit called with NULL params\n");
+		return -1; /* change to something symbolic */
+	}
+
+	if (!(skb->tc_verd & TC_OK2MUNGE)) {
+		/* should we set skb->cloned? */
+		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
+			return p->action;
+		}
+	}
+
+	pptr = skb->nh.raw;
+
+	spin_lock(&p->lock);
+
+	p->tm.lastuse = jiffies;
+
+	if (0 < p->nkeys) {
+		struct tc_pedit_key *tkey = p->keys;
+
+		for (i = p->nkeys; i > 0; i--, tkey++) {
+			u32 *ptr ;
+
+			int offset = tkey->off;
+			if (tkey->offmask) {
+				if (skb->len > tkey->at) {
+					 char *j = pptr+tkey->at;
+					 offset +=((*j&tkey->offmask)>>tkey->shift);
+				} else {
+					goto bad;
+				}
+			}
+
+			if (offset % 4) {
+				printk("offset must be on 32 bit boundaries\n");
+				goto bad;
+			}
+
+			if (skb->len < 0 || (offset > 0 && offset > skb->len)) {
+				printk("offset %d cant exceed pkt length %d\n",
+						offset, skb->len);
+				goto bad;
+			}
+
+
+			ptr = (u32 *)(pptr+offset);
+			/* just do it, baby */
+			*ptr = ((*ptr & tkey->mask) ^ tkey->val);
+			munged++;
+		}
+		
+		if (munged)
+			skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
+		goto done;
+	} else {
+		printk("pedit BUG: index %d\n",p->index);
+	}
+
+bad:
+	p->stats.overlimits++;
+done:
+	p->stats.bytes += skb->len;
+	p->stats.packets++;
+	spin_unlock(&p->lock);
+	return p->action;
+}
+
+int
+tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,int bind, int ref)
+{
+	unsigned char *b = skb->tail;
+	struct tc_pedit *opt;
+	struct tcf_pedit *p;
+	struct tcf_t t;
+	int s; 
+		
+
+	p = PRIV(a,pedit);
+
+	if (NULL == p) {
+		printk("BUG: tcf_pedit_dump called with NULL params\n");
+		goto rtattr_failure;
+	}
+
+	s = sizeof (*opt)+(p->nkeys*sizeof(struct tc_pedit_key));
+
+	/* netlink spinlocks held above us - must use ATOMIC
+	 * */
+	opt = kmalloc(s, GFP_ATOMIC);
+	if (opt == NULL)
+		return -ENOBUFS;
+
+	memset(opt, 0, s);
+
+	memcpy(opt->keys,p->keys,p->nkeys*(sizeof(struct tc_pedit_key)));
+	opt->index = p->index;
+	opt->nkeys = p->nkeys;
+	opt->flags = p->flags;
+	opt->action = p->action;
+	opt->refcnt = p->refcnt - ref;
+	opt->bindcnt = p->bindcnt - bind;
+
+
+#ifdef PEDIT_DEB
+	{                
+		/* Debug - get rid of later */
+		int i;
+		struct tc_pedit_key *key = opt->keys;
+
+		for (i=0; i<opt->nkeys; i++, key++) {
+			printk( "\n key #%d",i);
+			printk( "  at %d: val %08x mask %08x",
+			(unsigned int)key->off,
+			(unsigned int)key->val,
+			(unsigned int)key->mask);
+												}
+											}
+#endif
+
+	RTA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
+	t.install = jiffies - p->tm.install;
+	t.lastuse = jiffies - p->tm.lastuse;
+	t.expires = p->tm.expires;
+	RTA_PUT(skb, TCA_PEDIT_TM, sizeof (t), &t);
+	return skb->len;
+
+rtattr_failure:
+	skb_trim(skb, b - skb->data);
+	return -1;
+}
+
+int
+tcf_pedit_stats(struct sk_buff *skb, struct tc_action *a)
+{
+	struct tcf_pedit *p;
+	p = PRIV(a,pedit);
+	if (NULL != p)
+		return qdisc_copy_stats(skb, &p->stats, p->stats_lock);
+
+	return 1;
+}
+
+static
+struct tc_action_ops act_pedit_ops = {
+	.kind		=	"pedit",
+	.type		=	TCA_ACT_PEDIT,
+	.capab		=	TCA_CAP_NONE,
+	.owner		=	THIS_MODULE,
+	.act		=	tcf_pedit,
+	.get_stats	=	tcf_pedit_stats,
+	.dump		=	tcf_pedit_dump,
+	.cleanup	=	tcf_pedit_cleanup,
+	.lookup		=	tcf_hash_search,
+	.init		=	tcf_pedit_init,
+	.walk		=	tcf_generic_walker
+};
+
+MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
+MODULE_DESCRIPTION("Generic Packet Editor actions");
+MODULE_LICENSE("GPL");
+
+static int __init
+pedit_init_module(void)
+{
+	return tcf_register_action(&act_pedit_ops);
+}
+
+static void __exit
+pedit_cleanup_module(void)
+{
+	tcf_unregister_action(&act_pedit_ops);
+}
+
+module_init(pedit_init_module);
+module_exit(pedit_cleanup_module);
+