kNFSd - 6 of 6 - Make sure nfsd replies from the address the request was sent to.

This is important on multi-homes hosts.

diff ./include/linux/sunrpc/svc.h~current~ ./include/linux/sunrpc/svc.h
-- ./include/linux/sunrpc/svc.h~current~ 2003-09-04 11:32:11.000000000 +1000
+++ ./include/linux/sunrpc/svc.h 2003-09-04 11:46:27.000000000 +1000

(quoted diff) +2 -0

@@ -112,6 +112,8 @@ struct svc_rqst {
 				rq_secure  : 1,	/* secure port */
 				rq_auth    : 1;	/* check client */
 
+	__u32			rq_daddr;	/* dest addr of request - reply from here */
+
 	void *			rq_argp;	/* decoded arguments */
 	void *			rq_resp;	/* xdr'd results */
 

diff ./net/sunrpc/svcsock.c~current~ ./net/sunrpc/svcsock.c
-- ./net/sunrpc/svcsock.c~current~ 2003-09-04 11:45:48.000000000 +1000
+++ ./net/sunrpc/svcsock.c 2003-09-04 11:46:27.000000000 +1000

(quoted diff) +15 -2

@@ -317,6 +317,9 @@ svc_sendto(struct svc_rqst *rqstp, struc
 	struct svc_sock	*svsk = rqstp->rq_sock;
 	struct socket	*sock = svsk->sk_sock;
 	struct msghdr	msg;
+	struct { struct cmsghdr cmh;
+		struct in_pktinfo pki;
+	} cm;
 	int		i, buflen, len;
 
 	for (i = buflen = 0; i < nr; i++)

@@ -326,8 +329,18 @@ svc_sendto(struct svc_rqst *rqstp, struc
 	msg.msg_namelen = sizeof(rqstp->rq_addr);
 	msg.msg_iov     = iov;
 	msg.msg_iovlen  = nr;
-	msg.msg_control = NULL;
-	msg.msg_controllen = 0;
+	if (rqstp->rq_prot == IPPROTO_UDP) {
+		msg.msg_control = &cm;
+		msg.msg_controllen = sizeof(cm);
+		cm.cmh.cmsg_len = sizeof(cm);
+		cm.cmh.cmsg_level = SOL_IP;
+		cm.cmh.cmsg_type = IP_PKTINFO;
+		cm.pki.ipi_ifindex = 0;
+		cm.pki.ipi_spec_dst.s_addr = rqstp->rq_daddr;
+	} else {
+		msg.msg_control = NULL;
+		msg.msg_controllen = 0;
+	}
 
 	/* This was MSG_DONTWAIT, but I now want it to wait.
 	 * The only thing that it would wait for is memory and

Hello,

the patch contains an alignment induced bug on 64-bit platforms:
sizeof(cm) becomes 32 bytes, instead of 16 + 12 = 28. This causes ip_cmsg_send to fail. See the attached fix.

Quoted 5 lines · Andreas Gruenbacher

Hello,

the patch contains an alignment induced bug on 64-bit platforms:
sizeof(cm) becomes 32 bytes, instead of 16 + 12 = 28. This causes ip_cmsg_send to fail. See the attached fix.

In addition, with the patch applied, I am seeing the following failure on ia64:

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