SUNRPC: split upcall function to extract reusable parts

This is needed to share code between the current server upcall mechanism
and the new gssproxy upcall mechanism introduced in a following patch.
Signed-off-by: NSimo Sorce <simo@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

net/sunrpc/auth_gss/svcauth_gss.c

@@ -964,16 +964,17 @@ svcauth_gss_set_client(struct svc_rqst *rqstp)
 }
 
 static inline int
-gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp, struct rsi *rsip)
+gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp,
+		struct xdr_netobj *out_handle, int *major_status)
 {
 	struct rsc *rsci;
 	int        rc;
 
-	if (rsip->major_status != GSS_S_COMPLETE)
+	if (*major_status != GSS_S_COMPLETE)
 		return gss_write_null_verf(rqstp);
-	rsci = gss_svc_searchbyctx(cd, &rsip->out_handle);
+	rsci = gss_svc_searchbyctx(cd, out_handle);
 	if (rsci == NULL) {
-		rsip->major_status = GSS_S_NO_CONTEXT;
+		*major_status = GSS_S_NO_CONTEXT;
 		return gss_write_null_verf(rqstp);
 	}
 	rc = gss_write_verf(rqstp, rsci->mechctx, GSS_SEQ_WIN);
@@ -981,22 +982,13 @@ gss_write_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp, struct rsi
 	return rc;
 }
 
-/*
- * Having read the cred already and found we're in the context
- * initiation case, read the verifier and initiate (or check the results
- * of) upcalls to userspace for help with context initiation.  If
- * the upcall results are available, write the verifier and result.
- * Otherwise, drop the request pending an answer to the upcall.
- */
-static int svcauth_gss_handle_init(struct svc_rqst *rqstp,
-			struct rpc_gss_wire_cred *gc, __be32 *authp)
+static inline int
+gss_read_verf(struct rpc_gss_wire_cred *gc,
+	      struct kvec *argv, __be32 *authp,
+	      struct xdr_netobj *in_handle,
+	      struct xdr_netobj *in_token)
 {
-	struct kvec *argv = &rqstp->rq_arg.head[0];
-	struct kvec *resv = &rqstp->rq_res.head[0];
 	struct xdr_netobj tmpobj;
-	struct rsi *rsip, rsikey;
-	int ret;
-	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
 
 	/* Read the verifier; should be NULL: */
 	*authp = rpc_autherr_badverf;
@@ -1006,24 +998,67 @@ static int svcauth_gss_handle_init(struct svc_rqst *rqstp,
 		return SVC_DENIED;
 	if (svc_getnl(argv) != 0)
 		return SVC_DENIED;
-
 	/* Martial context handle and token for upcall: */
 	*authp = rpc_autherr_badcred;
 	if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
 		return SVC_DENIED;
-	memset(&rsikey, 0, sizeof(rsikey));
-	if (dup_netobj(&rsikey.in_handle, &gc->gc_ctx))
+	if (dup_netobj(in_handle, &gc->gc_ctx))
 		return SVC_CLOSE;
 	*authp = rpc_autherr_badverf;
 	if (svc_safe_getnetobj(argv, &tmpobj)) {
-		kfree(rsikey.in_handle.data);
+		kfree(in_handle->data);
 		return SVC_DENIED;
 	}
-	if (dup_netobj(&rsikey.in_token, &tmpobj)) {
-		kfree(rsikey.in_handle.data);
+	if (dup_netobj(in_token, &tmpobj)) {
+		kfree(in_handle->data);
 		return SVC_CLOSE;
 	}
 
+	return 0;
+}
+
+static inline int
+gss_write_resv(struct kvec *resv, size_t size_limit,
+	       struct xdr_netobj *out_handle, struct xdr_netobj *out_token,
+	       int major_status, int minor_status)
+{
+	if (resv->iov_len + 4 > size_limit)
+		return -1;
+	svc_putnl(resv, RPC_SUCCESS);
+	if (svc_safe_putnetobj(resv, out_handle))
+		return -1;
+	if (resv->iov_len + 3 * 4 > size_limit)
+		return -1;
+	svc_putnl(resv, major_status);
+	svc_putnl(resv, minor_status);
+	svc_putnl(resv, GSS_SEQ_WIN);
+	if (svc_safe_putnetobj(resv, out_token))
+		return -1;
+	return 0;
+}
+
+/*
+ * Having read the cred already and found we're in the context
+ * initiation case, read the verifier and initiate (or check the results
+ * of) upcalls to userspace for help with context initiation.  If
+ * the upcall results are available, write the verifier and result.
+ * Otherwise, drop the request pending an answer to the upcall.
+ */
+static int svcauth_gss_handle_init(struct svc_rqst *rqstp,
+			struct rpc_gss_wire_cred *gc, __be32 *authp)
+{
+	struct kvec *argv = &rqstp->rq_arg.head[0];
+	struct kvec *resv = &rqstp->rq_res.head[0];
+	struct rsi *rsip, rsikey;
+	int ret;
+	struct sunrpc_net *sn = net_generic(rqstp->rq_xprt->xpt_net, sunrpc_net_id);
+
+	memset(&rsikey, 0, sizeof(rsikey));
+	ret = gss_read_verf(gc, argv, authp,
+			    &rsikey.in_handle, &rsikey.in_token);
+	if (ret)
+		return ret;
+
 	/* Perform upcall, or find upcall result: */
 	rsip = rsi_lookup(sn->rsi_cache, &rsikey);
 	rsi_free(&rsikey);
@@ -1035,19 +1070,12 @@ static int svcauth_gss_handle_init(struct svc_rqst *rqstp,
 
 	ret = SVC_CLOSE;
 	/* Got an answer to the upcall; use it: */
-	if (gss_write_init_verf(sn->rsc_cache, rqstp, rsip))
+	if (gss_write_init_verf(sn->rsc_cache, rqstp,
+				&rsip->out_handle, &rsip->major_status))
 		goto out;
-	if (resv->iov_len + 4 > PAGE_SIZE)
-		goto out;
-	svc_putnl(resv, RPC_SUCCESS);
-	if (svc_safe_putnetobj(resv, &rsip->out_handle))
-		goto out;
-	if (resv->iov_len + 3 * 4 > PAGE_SIZE)
-		goto out;
-	svc_putnl(resv, rsip->major_status);
-	svc_putnl(resv, rsip->minor_status);
-	svc_putnl(resv, GSS_SEQ_WIN);
-	if (svc_safe_putnetobj(resv, &rsip->out_token))
+	if (gss_write_resv(resv, PAGE_SIZE,
+			   &rsip->out_handle, &rsip->out_token,
+			   rsip->major_status, rsip->minor_status))
 		goto out;
 
 	ret = SVC_COMPLETE;