[NETLINK]: illegal use of pid in rtnetlink

When a netlink message is not related to a netlink socket,
it is issued by kernel socket with pid 0. Netlink "pid" has nothing
to do with current->pid. I called it incorrectly, if it was named "port",
the confusion would be avoided.
Signed-off-by: NAlexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/rtnetlink.c

@@ -455,7 +455,7 @@ void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)
 	if (!skb)
 		return;
 
-	if (rtnetlink_fill_ifinfo(skb, dev, type, current->pid, 0, change, 0) < 0) {
+	if (rtnetlink_fill_ifinfo(skb, dev, type, 0, 0, change, 0) < 0) {
 		kfree_skb(skb);
 		return;
 	}

net/ipv4/devinet.c

@@ -1135,7 +1135,7 @@ static void rtmsg_ifa(int event, struct in_ifaddr* ifa)
 
 	if (!skb)
 		netlink_set_err(rtnl, 0, RTNLGRP_IPV4_IFADDR, ENOBUFS);
-	else if (inet_fill_ifaddr(skb, ifa, current->pid, 0, event, 0) < 0) {
+	else if (inet_fill_ifaddr(skb, ifa, 0, 0, event, 0) < 0) {
 		kfree_skb(skb);
 		netlink_set_err(rtnl, 0, RTNLGRP_IPV4_IFADDR, EINVAL);
 	} else {

net/ipv4/fib_semantics.c

@@ -1045,7 +1045,7 @@ fib_convert_rtentry(int cmd, struct nlmsghdr *nl, struct rtmsg *rtm,
 	}
 
 	nl->nlmsg_flags = NLM_F_REQUEST;
-	nl->nlmsg_pid = current->pid;
+	nl->nlmsg_pid = 0;
 	nl->nlmsg_seq = 0;
 	nl->nlmsg_len = NLMSG_LENGTH(sizeof(*rtm));
 	if (cmd == SIOCDELRT) {