From fd7de4624d694a57c56c995eedd7f3a8c37b1c28 Mon Sep 17 00:00:00 2001
From: Brian Swetland <swetland@google.com>
Date: Mon, 1 Nov 2010 14:50:57 +0800
Subject: Android ipv4: socket ioctl to reset connections matching local
 address

Introduce a new socket ioctl, SIOCKILLADDR, that nukes all sockets
bound to the same local address. This is useful in situations with
dynamic IPs, to kill stuck connections.

Signed-off-by: Brian Swetland <swetland@google.com>
---
 include/linux/sockios.h |  1 +
 include/net/tcp.h       |  2 ++
 net/ipv4/af_inet.c      |  1 +
 net/ipv4/devinet.c      |  9 ++++++++-
 net/ipv4/tcp_ipv4.c     | 43 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/include/linux/sockios.h b/include/linux/sockios.h
index 241f179347d9..f4fa1a164c74 100644
--- a/include/linux/sockios.h
+++ b/include/linux/sockios.h
@@ -65,6 +65,7 @@
 #define SIOCDIFADDR	0x8936		/* delete PA address		*/
 #define	SIOCSIFHWBROADCAST	0x8937	/* set hardware broadcast addr	*/
 #define SIOCGIFCOUNT	0x8938		/* get number of devices */
+#define SIOCKILLADDR	0x8939		/* kill sockets with this local addr */
 
 #define SIOCGIFBR	0x8940		/* Bridging support		*/
 #define SIOCSIFBR	0x8941		/* Set bridging options 	*/
diff --git a/include/net/tcp.h b/include/net/tcp.h
index a1449144848a..250698be4d99 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1433,6 +1433,8 @@ extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head,
 extern int tcp_gro_complete(struct sk_buff *skb);
 extern int tcp4_gro_complete(struct sk_buff *skb);
 
+extern void tcp_v4_nuke_addr(__u32 saddr);
+
 #ifdef CONFIG_PROC_FS
 extern int  tcp4_proc_init(void);
 extern void tcp4_proc_exit(void);
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 551ce564b035..6dac2d9f35ef 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -864,6 +864,7 @@ int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	case SIOCSIFPFLAGS:
 	case SIOCGIFPFLAGS:
 	case SIOCSIFFLAGS:
+	case SIOCKILLADDR:
 		err = devinet_ioctl(net, cmd, (void __user *)arg);
 		break;
 	default:
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index da14c49284f4..8b7dfaf3b6ea 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -58,6 +58,7 @@
 
 #include <net/arp.h>
 #include <net/ip.h>
+#include <net/tcp.h>
 #include <net/route.h>
 #include <net/ip_fib.h>
 #include <net/rtnetlink.h>
@@ -635,6 +636,7 @@ int devinet_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 	case SIOCSIFBRDADDR:	/* Set the broadcast address */
 	case SIOCSIFDSTADDR:	/* Set the destination address */
 	case SIOCSIFNETMASK: 	/* Set the netmask for the interface */
+	case SIOCKILLADDR:	/* Nuke all sockets on this address */
 		ret = -EACCES;
 		if (!capable(CAP_NET_ADMIN))
 			goto out;
@@ -686,7 +688,8 @@ int devinet_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 	}
 
 	ret = -EADDRNOTAVAIL;
-	if (!ifa && cmd != SIOCSIFADDR && cmd != SIOCSIFFLAGS)
+	if (!ifa && cmd != SIOCSIFADDR && cmd != SIOCSIFFLAGS
+	    && cmd != SIOCKILLADDR)
 		goto done;
 
 	switch (cmd) {
@@ -811,6 +814,10 @@ int devinet_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 			inet_insert_ifa(ifa);
 		}
 		break;
+	case SIOCKILLADDR:	/* Nuke all connections on this address */
+		ret = 0;
+		tcp_v4_nuke_addr(sin->sin_addr.s_addr);
+		break;
 	}
 done:
 	rtnl_unlock();
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index fe193e53af44..3c7b72437b58 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1963,6 +1963,49 @@ void tcp_v4_destroy_sock(struct sock *sk)
 
 EXPORT_SYMBOL(tcp_v4_destroy_sock);
 
+/*
+ * tcp_v4_nuke_addr - destroy all sockets on the given local address
+ */
+void tcp_v4_nuke_addr(__u32 saddr)
+{
+	unsigned int bucket;
+
+	for (bucket = 0; bucket < tcp_hashinfo.ehash_mask; bucket++) {
+		struct hlist_nulls_node *node;
+		struct sock *sk;
+		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, bucket);
+
+restart:
+		spin_lock_bh(lock);
+		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[bucket].chain) {
+			struct inet_sock *inet = inet_sk(sk);
+
+			if (inet->inet_rcv_saddr != saddr)
+				continue;
+			if (sysctl_ip_dynaddr && sk->sk_state == TCP_SYN_SENT)
+				continue;
+			if (sock_flag(sk, SOCK_DEAD))
+				continue;
+
+			sock_hold(sk);
+			spin_unlock_bh(lock);
+
+			local_bh_disable();
+			bh_lock_sock(sk);
+			sk->sk_err = ETIMEDOUT;
+			sk->sk_error_report(sk);
+
+			tcp_done(sk);
+			bh_unlock_sock(sk);
+			local_bh_enable();
+			sock_put(sk);
+
+			goto restart;
+		}
+		spin_unlock_bh(lock);
+	}
+}
+
 #ifdef CONFIG_PROC_FS
 /* Proc filesystem TCP sock list dumping. */
 
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