neighbour: fix nlmsg_pid in notifications

neigh notifications today carry pid 0 for nlmsg_pid
in all cases. This patch fixes it to carry calling process
pid when available. Applications (eg. quagga) rely on
nlmsg_pid to ignore notifications generated by their own
netlink operations. This patch follows the routing subsystem
which already sets this correctly.
Reported-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/neighbour.h

@@ -314,7 +314,8 @@ static inline struct neighbour *neigh_create(struct neigh_table *tbl,
 }
 void neigh_destroy(struct neighbour *neigh);
 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
-int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
+int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
+		 u32 nlmsg_pid);
 void __neigh_set_probe_once(struct neighbour *neigh);
 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);

net/atm/clip.c

@@ -106,7 +106,7 @@ static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
 			entry->expires = jiffies - 1;
 			/* force resolution or expiration */
 			error = neigh_update(entry->neigh, NULL, NUD_NONE,
-					     NEIGH_UPDATE_F_ADMIN);
+					     NEIGH_UPDATE_F_ADMIN, 0);
 			if (error)
 				pr_crit("neigh_update failed with %d\n", error);
 			goto out;
@@ -481,7 +481,7 @@ static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
 		link_vcc(clip_vcc, entry);
 	}
 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
-			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
+			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN, 0);
 	neigh_release(neigh);
 	return error;
 }

net/core/neighbour.c

@@ -52,8 +52,9 @@ do {						\
 #define PNEIGH_HASHMASK		0xF
 
 static void neigh_timer_handler(unsigned long arg);
-static void __neigh_notify(struct neighbour *n, int type, int flags);
-static void neigh_update_notify(struct neighbour *neigh);
+static void __neigh_notify(struct neighbour *n, int type, int flags,
+			   u32 pid);
+static void neigh_update_notify(struct neighbour *neigh, u32 nlmsg_pid);
 static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 
 #ifdef CONFIG_PROC_FS
@@ -99,7 +100,7 @@ static void neigh_cleanup_and_release(struct neighbour *neigh)
 	if (neigh->parms->neigh_cleanup)
 		neigh->parms->neigh_cleanup(neigh);
 
-	__neigh_notify(neigh, RTM_DELNEIGH, 0);
+	__neigh_notify(neigh, RTM_DELNEIGH, 0, 0);
 	call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
 	neigh_release(neigh);
 }
@@ -948,7 +949,7 @@ static void neigh_timer_handler(unsigned long arg)
 	}
 
 	if (notify)
-		neigh_update_notify(neigh);
+		neigh_update_notify(neigh, 0);
 
 	neigh_release(neigh);
 }
@@ -1072,7 +1073,7 @@ static void neigh_update_hhs(struct neighbour *neigh)
  */
 
 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
-		 u32 flags)
+		 u32 flags, u32 nlmsg_pid)
 {
 	u8 old;
 	int err;
@@ -1229,7 +1230,7 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 	write_unlock_bh(&neigh->lock);
 
 	if (notify)
-		neigh_update_notify(neigh);
+		neigh_update_notify(neigh, nlmsg_pid);
 
 	return err;
 }
@@ -1260,7 +1261,7 @@ struct neighbour *neigh_event_ns(struct neigh_table *tbl,
 						 lladdr || !dev->addr_len);
 	if (neigh)
 		neigh_update(neigh, lladdr, NUD_STALE,
-			     NEIGH_UPDATE_F_OVERRIDE);
+			     NEIGH_UPDATE_F_OVERRIDE, 0);
 	return neigh;
 }
 EXPORT_SYMBOL(neigh_event_ns);
@@ -1638,7 +1639,8 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 	err = neigh_update(neigh, NULL, NUD_FAILED,
 			   NEIGH_UPDATE_F_OVERRIDE |
-			   NEIGH_UPDATE_F_ADMIN);
+			   NEIGH_UPDATE_F_ADMIN,
+			   NETLINK_CB(skb).portid);
 	neigh_release(neigh);
 
 out:
@@ -1729,7 +1731,8 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh)
 		neigh_event_send(neigh, NULL);
 		err = 0;
 	} else
-		err = neigh_update(neigh, lladdr, ndm->ndm_state, flags);
+		err = neigh_update(neigh, lladdr, ndm->ndm_state, flags,
+				   NETLINK_CB(skb).portid);
 	neigh_release(neigh);
 
 out:
@@ -2229,10 +2232,10 @@ static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
 	return -EMSGSIZE;
 }
 
-static void neigh_update_notify(struct neighbour *neigh)
+static void neigh_update_notify(struct neighbour *neigh, u32 nlmsg_pid)
 {
 	call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
-	__neigh_notify(neigh, RTM_NEWNEIGH, 0);
+	__neigh_notify(neigh, RTM_NEWNEIGH, 0, nlmsg_pid);
 }
 
 static bool neigh_master_filtered(struct net_device *dev, int master_idx)
@@ -2830,7 +2833,8 @@ static inline size_t neigh_nlmsg_size(void)
 	       + nla_total_size(4); /* NDA_PROBES */
 }
 
-static void __neigh_notify(struct neighbour *n, int type, int flags)
+static void __neigh_notify(struct neighbour *n, int type, int flags,
+			   u32 pid)
 {
 	struct net *net = dev_net(n->dev);
 	struct sk_buff *skb;
@@ -2840,7 +2844,7 @@ static void __neigh_notify(struct neighbour *n, int type, int flags)
 	if (skb == NULL)
 		goto errout;
 
-	err = neigh_fill_info(skb, n, 0, 0, type, flags);
+	err = neigh_fill_info(skb, n, pid, 0, type, flags);
 	if (err < 0) {
 		/* -EMSGSIZE implies BUG in neigh_nlmsg_size() */
 		WARN_ON(err == -EMSGSIZE);
@@ -2856,7 +2860,7 @@ static void __neigh_notify(struct neighbour *n, int type, int flags)
 
 void neigh_app_ns(struct neighbour *n)
 {
-	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
+	__neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST, 0);
 }
 EXPORT_SYMBOL(neigh_app_ns);
 

net/ipv4/arp.c

@@ -872,7 +872,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
 		    skb->pkt_type != PACKET_HOST)
 			state = NUD_STALE;
 		neigh_update(n, sha, state,
-			     override ? NEIGH_UPDATE_F_OVERRIDE : 0);
+			     override ? NEIGH_UPDATE_F_OVERRIDE : 0, 0);
 		neigh_release(n);
 	}
 
@@ -1033,7 +1033,7 @@ static int arp_req_set(struct net *net, struct arpreq *r,
 		err = neigh_update(neigh, (r->arp_flags & ATF_COM) ?
 				   r->arp_ha.sa_data : NULL, state,
 				   NEIGH_UPDATE_F_OVERRIDE |
-				   NEIGH_UPDATE_F_ADMIN);
+				   NEIGH_UPDATE_F_ADMIN, 0);
 		neigh_release(neigh);
 	}
 	return err;
@@ -1084,7 +1084,7 @@ static int arp_invalidate(struct net_device *dev, __be32 ip)
 		if (neigh->nud_state & ~NUD_NOARP)
 			err = neigh_update(neigh, NULL, NUD_FAILED,
 					   NEIGH_UPDATE_F_OVERRIDE|
-					   NEIGH_UPDATE_F_ADMIN);
+					   NEIGH_UPDATE_F_ADMIN, 0);
 		neigh_release(neigh);
 	}
 

net/ipv6/ndisc.c

@@ -732,7 +732,7 @@ void ndisc_update(const struct net_device *dev, struct neighbour *neigh,
 		  const u8 *lladdr, u8 new, u32 flags, u8 icmp6_type,
 		  struct ndisc_options *ndopts)
 {
-	neigh_update(neigh, lladdr, new, flags);
+	neigh_update(neigh, lladdr, new, flags, 0);
 	/* report ndisc ops about neighbour update */
 	ndisc_ops_update(dev, neigh, flags, icmp6_type, ndopts);
 }