1 files changed, 40 insertions, 32 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 63ae94771b8e..32b94cf19f89 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -721,45 +721,23 @@ svc_write_space(struct sock *sk)
 	}
 }
 
-static void svc_udp_get_sender_address(struct svc_rqst *rqstp,
-					struct sk_buff *skb)
+static inline void svc_udp_get_dest_address(struct svc_rqst *rqstp,
+					    struct cmsghdr *cmh)
 {
 	switch (rqstp->rq_sock->sk_sk->sk_family) {
 	case AF_INET: {
-		/* this seems to come from net/ipv4/udp.c:udp_recvmsg */
-			struct sockaddr_in *sin = svc_addr_in(rqstp);
-
-			sin->sin_family = AF_INET;
-			sin->sin_port = skb->h.uh->source;
-			sin->sin_addr.s_addr = skb->nh.iph->saddr;
-			rqstp->rq_addrlen = sizeof(struct sockaddr_in);
-			/* Remember which interface received this request */
-			rqstp->rq_daddr.addr.s_addr = skb->nh.iph->daddr;
-		}
+		struct in_pktinfo *pki = CMSG_DATA(cmh);
+		rqstp->rq_daddr.addr.s_addr = pki->ipi_spec_dst.s_addr;
 		break;
+		}
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6: {
-		/* this is derived from net/ipv6/udp.c:udpv6_recvmesg */
-			struct sockaddr_in6 *sin6 = svc_addr_in6(rqstp);
-
-			sin6->sin6_family = AF_INET6;
-			sin6->sin6_port = skb->h.uh->source;
-			sin6->sin6_flowinfo = 0;
-			sin6->sin6_scope_id = 0;
-			if (ipv6_addr_type(&sin6->sin6_addr) &
-							IPV6_ADDR_LINKLOCAL)
-				sin6->sin6_scope_id = IP6CB(skb)->iif;
-			ipv6_addr_copy(&sin6->sin6_addr,
-							&skb->nh.ipv6h->saddr);
-			rqstp->rq_addrlen = sizeof(struct sockaddr_in);
-			/* Remember which interface received this request */
-			ipv6_addr_copy(&rqstp->rq_daddr.addr6,
-							&skb->nh.ipv6h->saddr);
-		}
+		struct in6_pktinfo *pki = CMSG_DATA(cmh);
+		ipv6_addr_copy(&rqstp->rq_daddr.addr6, &pki->ipi6_addr);
 		break;
+		}
 #endif
 	}
-	return;
 }
 
 /*
@@ -771,7 +749,15 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
 	struct svc_sock	*svsk = rqstp->rq_sock;
 	struct svc_serv	*serv = svsk->sk_server;
 	struct sk_buff	*skb;
+	char		buffer[CMSG_SPACE(sizeof(union svc_pktinfo_u))];
+	struct cmsghdr *cmh = (struct cmsghdr *)buffer;
 	int		err, len;
+	struct msghdr msg = {
+		.msg_name = svc_addr(rqstp),
+		.msg_control = cmh,
+		.msg_controllen = sizeof(buffer),
+		.msg_flags = MSG_DONTWAIT,
+	};
 
 	if (test_and_clear_bit(SK_CHNGBUF, &svsk->sk_flags))
 	    /* udp sockets need large rcvbuf as all pending
@@ -797,7 +783,9 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
 	}
 
 	clear_bit(SK_DATA, &svsk->sk_flags);
-	while ((skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err)) == NULL) {
+	while ((err == kernel_recvmsg(svsk->sk_sock, &msg, NULL,
+				      0, 0, MSG_PEEK | MSG_DONTWAIT)) < 0 ||
+	       (skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err)) == NULL) {
 		if (err == -EAGAIN) {
 			svc_sock_received(svsk);
 			return err;
@@ -805,6 +793,7 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
 		/* possibly an icmp error */
 		dprintk("svc: recvfrom returned error %d\n", -err);
 	}
+	rqstp->rq_addrlen = sizeof(rqstp->rq_addr);
 	if (skb->tstamp.off_sec == 0) {
 		struct timeval tv;
 
@@ -827,7 +816,16 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
 
 	rqstp->rq_prot = IPPROTO_UDP;
 
-	svc_udp_get_sender_address(rqstp, skb);
+	if (cmh->cmsg_level != IPPROTO_IP ||
+	    cmh->cmsg_type != IP_PKTINFO) {
+		if (net_ratelimit())
+			printk("rpcsvc: received unknown control message:"
+			       "%d/%d\n",
+			       cmh->cmsg_level, cmh->cmsg_type);
+		skb_free_datagram(svsk->sk_sk, skb);
+		return 0;
+	}
+	svc_udp_get_dest_address(rqstp, cmh);
 
 	if (skb_is_nonlinear(skb)) {
 		/* we have to copy */
@@ -884,6 +882,9 @@ svc_udp_sendto(struct svc_rqst *rqstp)
 static void
 svc_udp_init(struct svc_sock *svsk)
 {
+	int one = 1;
+	mm_segment_t oldfs;
+
 	svsk->sk_sk->sk_data_ready = svc_udp_data_ready;
 	svsk->sk_sk->sk_write_space = svc_write_space;
 	svsk->sk_recvfrom = svc_udp_recvfrom;
@@ -899,6 +900,13 @@ svc_udp_init(struct svc_sock *svsk)
 
 	set_bit(SK_DATA, &svsk->sk_flags); /* might have come in before data_ready set up */
 	set_bit(SK_CHNGBUF, &svsk->sk_flags);
+
+	oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	/* make sure we get destination address info */
+	svsk->sk_sock->ops->setsockopt(svsk->sk_sock, IPPROTO_IP, IP_PKTINFO,
+				       (char __user *)&one, sizeof(one));
+	set_fs(oldfs);
 }
 
 /*