[NETFILTER]: Move reroute-after-queue code up to the nf_queue layer.

The rerouting functionality is required by the core, therefore it has
to be implemented by the core and not in individual queue handlers.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter.h

@@ -198,6 +198,17 @@ extern void nf_invalidate_cache(int pf);
    Returns true or false. */
 extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
 
+struct nf_queue_rerouter {
+	void (*save)(const struct sk_buff *skb, struct nf_info *info);
+	int (*reroute)(struct sk_buff **skb, const struct nf_info *info);
+	int rer_size;
+};
+
+#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
+
+extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer);
+extern int nf_unregister_queue_rerouter(int pf);
+
 #else /* !CONFIG_NETFILTER */
 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}

include/linux/netfilter_ipv6.h

@@ -71,4 +71,7 @@ enum nf_ip6_hook_priorities {
 	NF_IP6_PRI_LAST = INT_MAX,
 };
 
+int ipv6_netfilter_init(void);
+void ipv6_netfilter_fini(void);
+
 #endif /*__LINUX_IP6_NETFILTER_H*/

net/core/netfilter.c

@@ -53,6 +53,9 @@ static struct nf_queue_handler_t {
 	nf_queue_outfn_t outfn;
 	void *data;
 } queue_handler[NPROTO];
+
+static struct nf_queue_rerouter *queue_rerouter;
+
 static DEFINE_RWLOCK(queue_handler_lock);
 
 int nf_register_hook(struct nf_hook_ops *reg)
@@ -260,11 +263,34 @@ int nf_unregister_queue_handler(int pf)
 	return 0;
 }
 
+int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer)
+{
+	if (pf >= NPROTO)
+		return -EINVAL;
+
+	write_lock_bh(&queue_handler_lock);
+	memcpy(&queue_rerouter[pf], rer, sizeof(queue_rerouter[pf]));
+	write_unlock_bh(&queue_handler_lock);
+
+	return 0;
+}
+
+int nf_unregister_queue_rerouter(int pf)
+{
+	if (pf >= NPROTO)
+		return -EINVAL;
+
+	write_lock_bh(&queue_handler_lock);
+	memset(&queue_rerouter[pf], 0, sizeof(queue_rerouter[pf]));
+	write_unlock_bh(&queue_handler_lock);
+	return 0;
+}
+
 /* 
  * Any packet that leaves via this function must come back 
  * through nf_reinject().
  */
-static int nf_queue(struct sk_buff *skb, 
+static int nf_queue(struct sk_buff **skb, 
 		    struct list_head *elem, 
 		    int pf, unsigned int hook,
 		    struct net_device *indev,
@@ -282,17 +308,17 @@ static int nf_queue(struct sk_buff *skb,
 	read_lock(&queue_handler_lock);
 	if (!queue_handler[pf].outfn) {
 		read_unlock(&queue_handler_lock);
-		kfree_skb(skb);
+		kfree_skb(*skb);
 		return 1;
 	}
 
-	info = kmalloc(sizeof(*info), GFP_ATOMIC);
+	info = kmalloc(sizeof(*info)+queue_rerouter[pf].rer_size, GFP_ATOMIC);
 	if (!info) {
 		if (net_ratelimit())
 			printk(KERN_ERR "OOM queueing packet %p\n",
-			       skb);
+			       *skb);
 		read_unlock(&queue_handler_lock);
-		kfree_skb(skb);
+		kfree_skb(*skb);
 		return 1;
 	}
 
@@ -311,15 +337,21 @@ static int nf_queue(struct sk_buff *skb,
 	if (outdev) dev_hold(outdev);
 
 #ifdef CONFIG_BRIDGE_NETFILTER
-	if (skb->nf_bridge) {
-		physindev = skb->nf_bridge->physindev;
+	if ((*skb)->nf_bridge) {
+		physindev = (*skb)->nf_bridge->physindev;
 		if (physindev) dev_hold(physindev);
-		physoutdev = skb->nf_bridge->physoutdev;
+		physoutdev = (*skb)->nf_bridge->physoutdev;
 		if (physoutdev) dev_hold(physoutdev);
 	}
 #endif
+	if (queue_rerouter[pf].save)
+		queue_rerouter[pf].save(*skb, info);
+
+	status = queue_handler[pf].outfn(*skb, info, queue_handler[pf].data);
+
+	if (status >= 0 && queue_rerouter[pf].reroute)
+		status = queue_rerouter[pf].reroute(skb, info);
 
-	status = queue_handler[pf].outfn(skb, info, queue_handler[pf].data);
 	read_unlock(&queue_handler_lock);
 
 	if (status < 0) {
@@ -332,9 +364,11 @@ static int nf_queue(struct sk_buff *skb,
 #endif
 		module_put(info->elem->owner);
 		kfree(info);
-		kfree_skb(skb);
+		kfree_skb(*skb);
+
 		return 1;
 	}
+
 	return 1;
 }
 
@@ -365,7 +399,7 @@ int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
 		ret = -EPERM;
 	} else if (verdict == NF_QUEUE) {
 		NFDEBUG("nf_hook: Verdict = QUEUE.\n");
-		if (!nf_queue(*pskb, elem, pf, hook, indev, outdev, okfn))
+		if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn))
 			goto next_hook;
 	}
 unlock:
@@ -428,7 +462,7 @@ void nf_reinject(struct sk_buff *skb, struct nf_info *info,
 		break;
 
 	case NF_QUEUE:
-		if (!nf_queue(skb, elem, info->pf, info->hook, 
+		if (!nf_queue(&skb, elem, info->pf, info->hook, 
 			      info->indev, info->outdev, info->okfn))
 			goto next_hook;
 		break;
@@ -555,6 +589,12 @@ void __init netfilter_init(void)
 {
 	int i, h;
 
+	queue_rerouter = kmalloc(NPROTO * sizeof(struct nf_queue_rerouter),
+				 GFP_KERNEL);
+	if (!queue_rerouter)
+		panic("netfilter: cannot allocate queue rerouter array\n");
+	memset(queue_rerouter, 0, NPROTO * sizeof(struct nf_queue_rerouter));
+
 	for (i = 0; i < NPROTO; i++) {
 		for (h = 0; h < NF_MAX_HOOKS; h++)
 			INIT_LIST_HEAD(&nf_hooks[i][h]);
@@ -573,4 +613,6 @@ EXPORT_SYMBOL(nf_reinject);
 EXPORT_SYMBOL(nf_setsockopt);
 EXPORT_SYMBOL(nf_unregister_hook);
 EXPORT_SYMBOL(nf_unregister_queue_handler);
+EXPORT_SYMBOL_GPL(nf_register_queue_rerouter);
+EXPORT_SYMBOL_GPL(nf_unregister_queue_rerouter);
 EXPORT_SYMBOL(nf_unregister_sockopt);

net/ipv4/netfilter.c

@@ -1,10 +1,11 @@
-#include <linux/config.h>
+/* IPv4 specific functions of netfilter core */
 
+#include <linux/config.h>
 #ifdef CONFIG_NETFILTER
 
-/* IPv4 specific functions of netfilter core */
 #include <linux/kernel.h>
 #include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
 
 #include <linux/tcp.h>
 #include <linux/udp.h>
@@ -76,4 +77,63 @@ int ip_route_me_harder(struct sk_buff **pskb)
 	return 0;
 }
 EXPORT_SYMBOL(ip_route_me_harder);
+
+/*
+ * Extra routing may needed on local out, as the QUEUE target never
+ * returns control to the table.
+ */
+
+struct ip_rt_info {
+	u_int32_t daddr;
+	u_int32_t saddr;
+	u_int8_t tos;
+};
+
+static void queue_save(const struct sk_buff *skb, struct nf_info *info)
+{
+	struct ip_rt_info *rt_info = nf_info_reroute(info);
+
+	if (info->hook == NF_IP_LOCAL_OUT) {
+		const struct iphdr *iph = skb->nh.iph;
+
+		rt_info->tos = iph->tos;
+		rt_info->daddr = iph->daddr;
+		rt_info->saddr = iph->saddr;
+	}
+}
+
+static int queue_reroute(struct sk_buff **pskb, const struct nf_info *info)
+{
+	const struct ip_rt_info *rt_info = nf_info_reroute(info);
+
+	if (info->hook == NF_IP_LOCAL_OUT) {
+		struct iphdr *iph = (*pskb)->nh.iph;
+
+		if (!(iph->tos == rt_info->tos
+		      && iph->daddr == rt_info->daddr
+		      && iph->saddr == rt_info->saddr))
+			return ip_route_me_harder(pskb);
+	}
+	return 0;
+}
+
+static struct nf_queue_rerouter ip_reroute = {
+	.rer_size	= sizeof(struct ip_rt_info),
+	.save		= queue_save,
+	.reroute	= queue_reroute,
+};
+
+static int init(void)
+{
+	return nf_register_queue_rerouter(PF_INET, &ip_reroute);
+}
+
+static void fini(void)
+{
+	nf_unregister_queue_rerouter(PF_INET);
+}
+
+module_init(init);
+module_exit(fini);
+
 #endif /* CONFIG_NETFILTER */

net/ipv4/netfilter/ip_queue.c

@@ -43,17 +43,10 @@
 #define NET_IPQ_QMAX 2088
 #define NET_IPQ_QMAX_NAME "ip_queue_maxlen"
 
-struct ipq_rt_info {
-	__u8 tos;
-	__u32 daddr;
-	__u32 saddr;
-};
-
 struct ipq_queue_entry {
 	struct list_head list;
 	struct nf_info *info;
 	struct sk_buff *skb;
-	struct ipq_rt_info rt_info;
 };
 
 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
@@ -305,14 +298,6 @@ ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
 	entry->info = info;
 	entry->skb = skb;
 
-	if (entry->info->hook == NF_IP_LOCAL_OUT) {
-		struct iphdr *iph = skb->nh.iph;
-
-		entry->rt_info.tos = iph->tos;
-		entry->rt_info.daddr = iph->daddr;
-		entry->rt_info.saddr = iph->saddr;
-	}
-
 	nskb = ipq_build_packet_message(entry, &status);
 	if (nskb == NULL)
 		goto err_out_free;
@@ -393,18 +378,6 @@ ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 	memcpy(e->skb->data, v->payload, v->data_len);
 	e->skb->ip_summed = CHECKSUM_NONE;
 
-	/*
-	 * Extra routing may needed on local out, as the QUEUE target never
-	 * returns control to the table.
-	 */
-	if (e->info->hook == NF_IP_LOCAL_OUT) {
-		struct iphdr *iph = e->skb->nh.iph;
-
-		if (!(iph->tos == e->rt_info.tos
-		      && iph->daddr == e->rt_info.daddr
-		      && iph->saddr == e->rt_info.saddr))
-			return ip_route_me_harder(&e->skb);
-	}
 	return 0;
 }
 

net/ipv6/af_inet6.c

@@ -44,6 +44,7 @@
 #include <linux/netdevice.h>
 #include <linux/icmpv6.h>
 #include <linux/smp_lock.h>
+#include <linux/netfilter_ipv6.h>
 
 #include <net/ip.h>
 #include <net/ipv6.h>
@@ -757,6 +758,9 @@ static int __init inet6_init(void)
 	err = igmp6_init(&inet6_family_ops);
 	if (err)
 		goto igmp_fail;
+	err = ipv6_netfilter_init();
+	if (err)
+		goto netfilter_fail;
 	/* Create /proc/foo6 entries. */
 #ifdef CONFIG_PROC_FS
 	err = -ENOMEM;
@@ -813,6 +817,8 @@ static int __init inet6_init(void)
 	raw6_proc_exit();
 proc_raw6_fail:
 #endif
+	ipv6_netfilter_fini();
+netfilter_fail:
 	igmp6_cleanup();
 igmp_fail:
 	ndisc_cleanup();
@@ -852,6 +858,7 @@ static void __exit inet6_exit(void)
 	ip6_route_cleanup();
 	ipv6_packet_cleanup();
 	igmp6_cleanup();
+	ipv6_netfilter_fini();
 	ndisc_cleanup();
 	icmpv6_cleanup();
 #ifdef CONFIG_SYSCTL