[PATCH 05/19] SUNRPC: track whether a request is coming from a loop-back interface.

[NeilBrown]

If an incoming NFS request is coming from the local host, then
nfsd will need to perform some special handling.  So detect that
possibility and make the source visible in rq_local.

Signed-off-by: NeilBrown <neilb at suse.de>
---
 include/linux/sunrpc/svc.h      |    1 +
 include/linux/sunrpc/svc_xprt.h |    1 +
 net/sunrpc/svcsock.c            |   10 ++++++++++
 3 files changed, 12 insertions(+)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 04e763221246..a0dbbd1e00e9 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -254,6 +254,7 @@ struct svc_rqst {
 	u32			rq_prot;	/* IP protocol */
 	unsigned short
 				rq_secure  : 1;	/* secure port */
+	unsigned short		rq_local   : 1;	/* local request */
 
 	void *			rq_argp;	/* decoded arguments */
 	void *			rq_resp;	/* xdr'd results */
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index b05963f09ebf..b99bdfb0fcf9 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -63,6 +63,7 @@ struct svc_xprt {
 #define	XPT_DETACHED	10		/* detached from tempsocks list */
 #define XPT_LISTENER	11		/* listening endpoint */
 #define XPT_CACHE_AUTH	12		/* cache auth info */
+#define XPT_LOCAL	13		/* connection from loopback interface */
 
 	struct svc_serv		*xpt_server;	/* service for transport */
 	atomic_t    	    	xpt_reserved;	/* space on outq that is rsvd */
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index b6e59f0a9475..193115fe968c 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -811,6 +811,7 @@ static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
 	struct socket	*newsock;
 	struct svc_sock	*newsvsk;
 	int		err, slen;
+	struct dst_entry *dst;
 	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 
 	dprintk("svc: tcp_accept %p sock %p\n", svsk, sock);
@@ -867,6 +868,14 @@ static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
 	}
 	svc_xprt_set_local(&newsvsk->sk_xprt, sin, slen);
 
+	clear_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
+	rcu_read_lock();
+	dst = rcu_dereference(newsock->sk->sk_dst_cache);
+	if (dst && dst->dev &&
+	    (dst->dev->features & NETIF_F_LOOPBACK))
+		set_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
+	rcu_read_unlock();
+
 	if (serv->sv_stats)
 		serv->sv_stats->nettcpconn++;
 
@@ -1112,6 +1121,7 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
 
 	rqstp->rq_xprt_ctxt   = NULL;
 	rqstp->rq_prot	      = IPPROTO_TCP;
+	rqstp->rq_local	      = !!test_bit(XPT_LOCAL, &svsk->sk_xprt.xpt_flags);
 
 	p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
 	calldir = p[1];