[IPV4]: Replace __in_dev_get with __in_dev_get_rcu/rtnl

The following patch renames __in_dev_get() to __in_dev_get_rtnl() and
introduces __in_dev_get_rcu() to cover the second case.

1) RCU with refcnt should use in_dev_get().
2) RCU without refcnt should use __in_dev_get_rcu().
3) All others must hold RTNL and use __in_dev_get_rtnl().

There is one exception in net/ipv4/route.c which is in fact a pre-existing
race condition.  I've marked it as such so that we remember to fix it.

This patch is based on suggestions and prior work by Suzanne Wood and
Paul McKenney.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -2776,7 +2776,7 @@ static u32 bond_glean_dev_ip(struct net_device *dev)
 		return 0;
 
 	rcu_read_lock();
-	idev = __in_dev_get(dev);
+	idev = __in_dev_get_rcu(dev);
 	if (!idev)
 		goto out;
 

drivers/net/wan/sdlamain.c

@@ -57,6 +57,7 @@
 #include <linux/ioport.h>	/* request_region(), release_region() */
 #include <linux/wanrouter.h>	/* WAN router definitions */
 #include <linux/wanpipe.h>	/* WANPIPE common user API definitions */
+#include <linux/rcupdate.h>
 
 #include <linux/in.h>
 #include <asm/io.h>		/* phys_to_virt() */
@@ -1268,37 +1269,41 @@ unsigned long get_ip_address(struct net_device *dev, int option)
 	
 	struct in_ifaddr *ifaddr;
 	struct in_device *in_dev;
+	unsigned long addr = 0;
 
-	if ((in_dev = __in_dev_get(dev)) == NULL){
-		return 0;
+	rcu_read_lock();
+	if ((in_dev = __in_dev_get_rcu(dev)) == NULL){
+		goto out;
 	}
 
 	if ((ifaddr = in_dev->ifa_list)== NULL ){
-		return 0;
+		goto out;
 	}
 	
 	switch (option){
 
 	case WAN_LOCAL_IP:
-		return ifaddr->ifa_local;
+		addr = ifaddr->ifa_local;
 		break;
 	
 	case WAN_POINTOPOINT_IP:
-		return ifaddr->ifa_address;
+		addr = ifaddr->ifa_address;
 		break;	
 
 	case WAN_NETMASK_IP:
-		return ifaddr->ifa_mask;
+		addr = ifaddr->ifa_mask;
 		break;
 
 	case WAN_BROADCAST_IP:
-		return ifaddr->ifa_broadcast;
+		addr = ifaddr->ifa_broadcast;
 		break;
 	default:
-		return 0;
+		break;
 	}
 
-	return 0;
+out:
+	rcu_read_unlock();
+	return addr;
 }	
 
 void add_gateway(sdla_t *card, struct net_device *dev)

drivers/net/wan/syncppp.c

@@ -769,7 +769,7 @@ static void sppp_cisco_input (struct sppp *sp, struct sk_buff *skb)
 		u32 addr = 0, mask = ~0; /* FIXME: is the mask correct? */
 #ifdef CONFIG_INET
 		rcu_read_lock();
-		if ((in_dev = __in_dev_get(dev)) != NULL)
+		if ((in_dev = __in_dev_get_rcu(dev)) != NULL)
 		{
 			for (ifa=in_dev->ifa_list; ifa != NULL;
 				ifa=ifa->ifa_next) {

drivers/net/wireless/strip.c

@@ -1352,7 +1352,7 @@ static unsigned char *strip_make_packet(unsigned char *buffer,
 		struct in_device *in_dev;
 
 		rcu_read_lock();
-		in_dev = __in_dev_get(strip_info->dev);
+		in_dev = __in_dev_get_rcu(strip_info->dev);
 		if (in_dev == NULL) {
 			rcu_read_unlock();
 			return NULL;
@@ -1508,7 +1508,7 @@ static void strip_send(struct strip *strip_info, struct sk_buff *skb)
 
 		brd = addr = 0;
 		rcu_read_lock();
-		in_dev = __in_dev_get(strip_info->dev);
+		in_dev = __in_dev_get_rcu(strip_info->dev);
 		if (in_dev) {
 			if (in_dev->ifa_list) {
 				brd = in_dev->ifa_list->ifa_broadcast;

drivers/parisc/led.c

@@ -37,6 +37,7 @@
 #include <linux/proc_fs.h>
 #include <linux/ctype.h>
 #include <linux/blkdev.h>
+#include <linux/rcupdate.h>
 #include <asm/io.h>
 #include <asm/processor.h>
 #include <asm/hardware.h>
@@ -358,9 +359,10 @@ static __inline__ int led_get_net_activity(void)
 	/* we are running as tasklet, so locking dev_base 
 	 * for reading should be OK */
 	read_lock(&dev_base_lock);
+	rcu_read_lock();
 	for (dev = dev_base; dev; dev = dev->next) {
 	    struct net_device_stats *stats;
-	    struct in_device *in_dev = __in_dev_get(dev);
+	    struct in_device *in_dev = __in_dev_get_rcu(dev);
 	    if (!in_dev || !in_dev->ifa_list)
 		continue;
 	    if (LOOPBACK(in_dev->ifa_list->ifa_local))
@@ -371,6 +373,7 @@ static __inline__ int led_get_net_activity(void)
 	    rx_total += stats->rx_packets;
 	    tx_total += stats->tx_packets;
 	}
+	rcu_read_unlock();
 	read_unlock(&dev_base_lock);
 
 	retval = 0;

drivers/s390/net/qeth_main.c

@@ -5200,7 +5200,7 @@ qeth_free_vlan_addresses4(struct qeth_card *card, unsigned short vid)
 	if (!card->vlangrp)
 		return;
 	rcu_read_lock();
-	in_dev = __in_dev_get(card->vlangrp->vlan_devices[vid]);
+	in_dev = __in_dev_get_rcu(card->vlangrp->vlan_devices[vid]);
 	if (!in_dev)
 		goto out;
 	for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
@@ -7725,7 +7725,7 @@ qeth_arp_constructor(struct neighbour *neigh)
 		goto out;
 
 	rcu_read_lock();
-	in_dev = rcu_dereference(__in_dev_get(dev));
+	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev == NULL) {
 		rcu_read_unlock();
 		return -EINVAL;

include/linux/inetdevice.h

@@ -142,13 +142,21 @@ static __inline__ int bad_mask(u32 mask, u32 addr)
 
 #define endfor_ifa(in_dev) }
 
+static inline struct in_device *__in_dev_get_rcu(const struct net_device *dev)
+{
+	struct in_device *in_dev = dev->ip_ptr;
+	if (in_dev)
+		in_dev = rcu_dereference(in_dev);
+	return in_dev;
+}
+
 static __inline__ struct in_device *
 in_dev_get(const struct net_device *dev)
 {
 	struct in_device *in_dev;
 
 	rcu_read_lock();
-	in_dev = dev->ip_ptr;
+	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev)
 		atomic_inc(&in_dev->refcnt);
 	rcu_read_unlock();
@@ -156,7 +164,7 @@ in_dev_get(const struct net_device *dev)
 }
 
 static __inline__ struct in_device *
-__in_dev_get(const struct net_device *dev)
+__in_dev_get_rtnl(const struct net_device *dev)
 {
 	return (struct in_device*)dev->ip_ptr;
 }

net/atm/clip.c

@@ -310,7 +310,7 @@ static int clip_constructor(struct neighbour *neigh)
 	if (neigh->type != RTN_UNICAST) return -EINVAL;
 
 	rcu_read_lock();
-	in_dev = rcu_dereference(__in_dev_get(dev));
+	in_dev = __in_dev_get_rcu(dev);
 	if (!in_dev) {
 		rcu_read_unlock();
 		return -EINVAL;

net/core/netpoll.c

@@ -703,7 +703,7 @@ int netpoll_setup(struct netpoll *np)
 
 	if (!np->local_ip) {
 		rcu_read_lock();
-		in_dev = __in_dev_get(ndev);
+		in_dev = __in_dev_get_rcu(ndev);
 
 		if (!in_dev || !in_dev->ifa_list) {
 			rcu_read_unlock();

net/core/pktgen.c

@@ -1667,7 +1667,7 @@ static void pktgen_setup_inject(struct pktgen_dev *pkt_dev)
 			struct in_device *in_dev; 
 
 			rcu_read_lock();
-			in_dev = __in_dev_get(pkt_dev->odev);
+			in_dev = __in_dev_get_rcu(pkt_dev->odev);
 			if (in_dev) {
 				if (in_dev->ifa_list) {
 					pkt_dev->saddr_min = in_dev->ifa_list->ifa_address;

net/econet/af_econet.c

@@ -406,7 +406,7 @@ static int econet_sendmsg(struct kiocb *iocb, struct socket *sock,
 		unsigned long network = 0;
 
 		rcu_read_lock();
-		idev = __in_dev_get(dev);
+		idev = __in_dev_get_rcu(dev);
 		if (idev) {
 			if (idev->ifa_list)
 				network = ntohl(idev->ifa_list->ifa_address) & 

net/ipv4/arp.c

@@ -241,7 +241,7 @@ static int arp_constructor(struct neighbour *neigh)
 	neigh->type = inet_addr_type(addr);
 
 	rcu_read_lock();
-	in_dev = rcu_dereference(__in_dev_get(dev));
+	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev == NULL) {
 		rcu_read_unlock();
 		return -EINVAL;
@@ -989,8 +989,8 @@ static int arp_req_set(struct arpreq *r, struct net_device * dev)
 			ipv4_devconf.proxy_arp = 1;
 			return 0;
 		}
-		if (__in_dev_get(dev)) {
-			__in_dev_get(dev)->cnf.proxy_arp = 1;
+		if (__in_dev_get_rtnl(dev)) {
+			__in_dev_get_rtnl(dev)->cnf.proxy_arp = 1;
 			return 0;
 		}
 		return -ENXIO;
@@ -1095,8 +1095,8 @@ static int arp_req_delete(struct arpreq *r, struct net_device * dev)
 				ipv4_devconf.proxy_arp = 0;
 				return 0;
 			}
-			if (__in_dev_get(dev)) {
-				__in_dev_get(dev)->cnf.proxy_arp = 0;
+			if (__in_dev_get_rtnl(dev)) {
+				__in_dev_get_rtnl(dev)->cnf.proxy_arp = 0;
 				return 0;
 			}
 			return -ENXIO;

net/ipv4/devinet.c

@@ -351,7 +351,7 @@ static int inet_insert_ifa(struct in_ifaddr *ifa)
 
 static int inet_set_ifa(struct net_device *dev, struct in_ifaddr *ifa)
 {
-	struct in_device *in_dev = __in_dev_get(dev);
+	struct in_device *in_dev = __in_dev_get_rtnl(dev);
 
 	ASSERT_RTNL();
 
@@ -449,7 +449,7 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg
 		goto out;
 
 	rc = -ENOBUFS;
-	if ((in_dev = __in_dev_get(dev)) == NULL) {
+	if ((in_dev = __in_dev_get_rtnl(dev)) == NULL) {
 		in_dev = inetdev_init(dev);
 		if (!in_dev)
 			goto out;
@@ -584,7 +584,7 @@ int devinet_ioctl(unsigned int cmd, void __user *arg)
 	if (colon)
 		*colon = ':';
 
-	if ((in_dev = __in_dev_get(dev)) != NULL) {
+	if ((in_dev = __in_dev_get_rtnl(dev)) != NULL) {
 		if (tryaddrmatch) {
 			/* Matthias Andree */
 			/* compare label and address (4.4BSD style) */
@@ -748,7 +748,7 @@ int devinet_ioctl(unsigned int cmd, void __user *arg)
 
 static int inet_gifconf(struct net_device *dev, char __user *buf, int len)
 {
-	struct in_device *in_dev = __in_dev_get(dev);
+	struct in_device *in_dev = __in_dev_get_rtnl(dev);
 	struct in_ifaddr *ifa;
 	struct ifreq ifr;
 	int done = 0;
@@ -791,7 +791,7 @@ u32 inet_select_addr(const struct net_device *dev, u32 dst, int scope)
 	struct in_device *in_dev;
 
 	rcu_read_lock();
-	in_dev = __in_dev_get(dev);
+	in_dev = __in_dev_get_rcu(dev);
 	if (!in_dev)
 		goto no_in_dev;
 
@@ -818,7 +818,7 @@ u32 inet_select_addr(const struct net_device *dev, u32 dst, int scope)
 	read_lock(&dev_base_lock);
 	rcu_read_lock();
 	for (dev = dev_base; dev; dev = dev->next) {
-		if ((in_dev = __in_dev_get(dev)) == NULL)
+		if ((in_dev = __in_dev_get_rcu(dev)) == NULL)
 			continue;
 
 		for_primary_ifa(in_dev) {
@@ -887,7 +887,7 @@ u32 inet_confirm_addr(const struct net_device *dev, u32 dst, u32 local, int scop
 
 	if (dev) {
 		rcu_read_lock();
-		if ((in_dev = __in_dev_get(dev)))
+		if ((in_dev = __in_dev_get_rcu(dev)))
 			addr = confirm_addr_indev(in_dev, dst, local, scope);
 		rcu_read_unlock();
 
@@ -897,7 +897,7 @@ u32 inet_confirm_addr(const struct net_device *dev, u32 dst, u32 local, int scop
 	read_lock(&dev_base_lock);
 	rcu_read_lock();
 	for (dev = dev_base; dev; dev = dev->next) {
-		if ((in_dev = __in_dev_get(dev))) {
+		if ((in_dev = __in_dev_get_rcu(dev))) {
 			addr = confirm_addr_indev(in_dev, dst, local, scope);
 			if (addr)
 				break;
@@ -957,7 +957,7 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
 			 void *ptr)
 {
 	struct net_device *dev = ptr;
-	struct in_device *in_dev = __in_dev_get(dev);
+	struct in_device *in_dev = __in_dev_get_rtnl(dev);
 
 	ASSERT_RTNL();
 
@@ -1078,7 +1078,7 @@ static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
 		if (idx > s_idx)
 			s_ip_idx = 0;
 		rcu_read_lock();
-		if ((in_dev = __in_dev_get(dev)) == NULL) {
+		if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
 			rcu_read_unlock();
 			continue;
 		}
@@ -1149,7 +1149,7 @@ void inet_forward_change(void)
 	for (dev = dev_base; dev; dev = dev->next) {
 		struct in_device *in_dev;
 		rcu_read_lock();
-		in_dev = __in_dev_get(dev);
+		in_dev = __in_dev_get_rcu(dev);
 		if (in_dev)
 			in_dev->cnf.forwarding = on;
 		rcu_read_unlock();

net/ipv4/fib_frontend.c

@@ -173,7 +173,7 @@ int fib_validate_source(u32 src, u32 dst, u8 tos, int oif,
 
 	no_addr = rpf = 0;
 	rcu_read_lock();
-	in_dev = __in_dev_get(dev);
+	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev) {
 		no_addr = in_dev->ifa_list == NULL;
 		rpf = IN_DEV_RPFILTER(in_dev);
@@ -607,7 +607,7 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event,
 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
 	struct net_device *dev = ptr;
-	struct in_device *in_dev = __in_dev_get(dev);
+	struct in_device *in_dev = __in_dev_get_rtnl(dev);
 
 	if (event == NETDEV_UNREGISTER) {
 		fib_disable_ip(dev, 2);

net/ipv4/fib_semantics.c

@@ -1087,7 +1087,7 @@ fib_convert_rtentry(int cmd, struct nlmsghdr *nl, struct rtmsg *rtm,
 		rta->rta_oif = &dev->ifindex;
 		if (colon) {
 			struct in_ifaddr *ifa;
-			struct in_device *in_dev = __in_dev_get(dev);
+			struct in_device *in_dev = __in_dev_get_rtnl(dev);
 			if (!in_dev)
 				return -ENODEV;
 			*colon = ':';
@@ -1268,7 +1268,7 @@ int fib_sync_up(struct net_device *dev)
 			}
 			if (nh->nh_dev == NULL || !(nh->nh_dev->flags&IFF_UP))
 				continue;
-			if (nh->nh_dev != dev || __in_dev_get(dev) == NULL)
+			if (nh->nh_dev != dev || !__in_dev_get_rtnl(dev))
 				continue;
 			alive++;
 			spin_lock_bh(&fib_multipath_lock);

net/ipv4/igmp.c

@@ -1323,7 +1323,7 @@ static struct in_device * ip_mc_find_dev(struct ip_mreqn *imr)
 	}
 	if (dev) {
 		imr->imr_ifindex = dev->ifindex;
-		idev = __in_dev_get(dev);
+		idev = __in_dev_get_rtnl(dev);
 	}
 	return idev;
 }

net/ipv4/ip_gre.c

@@ -1104,10 +1104,10 @@ static int ipgre_open(struct net_device *dev)
 			return -EADDRNOTAVAIL;
 		dev = rt->u.dst.dev;
 		ip_rt_put(rt);
-		if (__in_dev_get(dev) == NULL)
+		if (__in_dev_get_rtnl(dev) == NULL)
 			return -EADDRNOTAVAIL;
 		t->mlink = dev->ifindex;
-		ip_mc_inc_group(__in_dev_get(dev), t->parms.iph.daddr);
+		ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
 	}
 	return 0;
 }

net/ipv4/ipmr.c

@@ -149,7 +149,7 @@ struct net_device *ipmr_new_tunnel(struct vifctl *v)
 		if (err == 0 && (dev = __dev_get_by_name(p.name)) != NULL) {
 			dev->flags |= IFF_MULTICAST;
 
-			in_dev = __in_dev_get(dev);
+			in_dev = __in_dev_get_rtnl(dev);
 			if (in_dev == NULL && (in_dev = inetdev_init(dev)) == NULL)
 				goto failure;
 			in_dev->cnf.rp_filter = 0;
@@ -278,7 +278,7 @@ static int vif_delete(int vifi)
 
 	dev_set_allmulti(dev, -1);
 
-	if ((in_dev = __in_dev_get(dev)) != NULL) {
+	if ((in_dev = __in_dev_get_rtnl(dev)) != NULL) {
 		in_dev->cnf.mc_forwarding--;
 		ip_rt_multicast_event(in_dev);
 	}
@@ -421,7 +421,7 @@ static int vif_add(struct vifctl *vifc, int mrtsock)
 		return -EINVAL;
 	}
 
-	if ((in_dev = __in_dev_get(dev)) == NULL)
+	if ((in_dev = __in_dev_get_rtnl(dev)) == NULL)
 		return -EADDRNOTAVAIL;
 	in_dev->cnf.mc_forwarding++;
 	dev_set_allmulti(dev, +1);

net/ipv4/netfilter/ip_conntrack_netbios_ns.c

@@ -58,7 +58,7 @@ static int help(struct sk_buff **pskb,
 		goto out;
 
 	rcu_read_lock();
-	in_dev = __in_dev_get(rt->u.dst.dev);
+	in_dev = __in_dev_get_rcu(rt->u.dst.dev);
 	if (in_dev != NULL) {
 		for_primary_ifa(in_dev) {
 			if (ifa->ifa_broadcast == iph->daddr) {

net/ipv4/netfilter/ipt_REDIRECT.c

@@ -93,7 +93,7 @@ redirect_target(struct sk_buff **pskb,
 		newdst = 0;
 		
 		rcu_read_lock();
-		indev = __in_dev_get((*pskb)->dev);
+		indev = __in_dev_get_rcu((*pskb)->dev);
 		if (indev && (ifa = indev->ifa_list))
 			newdst = ifa->ifa_local;
 		rcu_read_unlock();

net/ipv4/route.c

@@ -2128,7 +2128,7 @@ int ip_route_input(struct sk_buff *skb, u32 daddr, u32 saddr,
 		struct in_device *in_dev;
 
 		rcu_read_lock();
-		if ((in_dev = __in_dev_get(dev)) != NULL) {
+		if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
 			int our = ip_check_mc(in_dev, daddr, saddr,
 				skb->nh.iph->protocol);
 			if (our
@@ -2443,7 +2443,9 @@ static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
 		err = -ENODEV;
 		if (dev_out == NULL)
 			goto out;
-		if (__in_dev_get(dev_out) == NULL) {
+
+		/* RACE: Check return value of inet_select_addr instead. */
+		if (__in_dev_get_rtnl(dev_out) == NULL) {
 			dev_put(dev_out);
 			goto out;	/* Wrong error code */
 		}

net/ipv6/addrconf.c

@@ -1806,7 +1806,7 @@ static void sit_add_v4_addrs(struct inet6_dev *idev)
 	}
 
         for (dev = dev_base; dev != NULL; dev = dev->next) {
-		struct in_device * in_dev = __in_dev_get(dev);
+		struct in_device * in_dev = __in_dev_get_rtnl(dev);
 		if (in_dev && (dev->flags & IFF_UP)) {
 			struct in_ifaddr * ifa;
 

net/irda/irlan/irlan_eth.c

@@ -310,7 +310,7 @@ void irlan_eth_send_gratuitous_arp(struct net_device *dev)
 #ifdef CONFIG_INET
 	IRDA_DEBUG(4, "IrLAN: Sending gratuitous ARP\n");
 	rcu_read_lock();
-	in_dev = __in_dev_get(dev);
+	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev == NULL)
 		goto out;
 	if (in_dev->ifa_list)

net/sctp/protocol.c

@@ -147,7 +147,7 @@ static void sctp_v4_copy_addrlist(struct list_head *addrlist,
 	struct sctp_sockaddr_entry *addr;
 
 	rcu_read_lock();
-	if ((in_dev = __in_dev_get(dev)) == NULL) {
+	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
 		rcu_read_unlock();
 		return;
 	}