nfsd: populate sin6_scope_id on callback address with scopeid from rq_addr on SETCLIENTID call

When a SETCLIENTID call comes in, one of the args given is the svc_rqst.
This struct contains an rq_addr field which holds the address that sent
the call. If this is an IPv6 address, then we can use the sin6_scope_id
field in this address to populate the sin6_scope_id field in the
callback address.

AFAICT, the rq_addr.sin6_scope_id is non-zero if and only if the client
mounted the server's link-local address.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 044f531aee70..3d025588e56e 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -286,5 +286,20 @@ static inline bool rpc_copy_addr(struct sockaddr *dst,
         return false;
 }
 
+/**
+ * rpc_get_scope_id - return scopeid for a given sockaddr
+ * @sa: sockaddr to get scopeid from
+ *
+ * Returns the value of the sin6_scope_id for AF_INET6 addrs, or 0 if
+ * not an AF_INET6 address.
+ */
+static inline u32 rpc_get_scope_id(const struct sockaddr *sa)
+{
+        if (sa->sa_family != AF_INET6)
+                return 0;
+
+        return ((struct sockaddr_in6 *) sa)->sin6_scope_id;
+}
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_SUNRPC_CLNT_H */