1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Encode/decode NLM basic data types
4  *
5  * Basic NLMv3 XDR data types are not defined in an IETF standards
6  * document.  X/Open has a description of these data types that
7  * is useful.  See Chapter 10 of "Protocols for Interworking:
8  * XNFS, Version 3W".
9  *
10  * Basic NLMv4 XDR data types are defined in Appendix II.1.4 of
11  * RFC 1813: "NFS Version 3 Protocol Specification".
12  *
13  * Author: Chuck Lever <chuck.lever@oracle.com>
14  *
15  * Copyright (c) 2020, Oracle and/or its affiliates.
16  */
17 
18 #ifndef _LOCKD_SVCXDR_H_
19 #define _LOCKD_SVCXDR_H_
20 
21 static inline bool
svcxdr_decode_stats(struct xdr_stream * xdr,__be32 * status)22 svcxdr_decode_stats(struct xdr_stream *xdr, __be32 *status)
23 {
24 	__be32 *p;
25 
26 	p = xdr_inline_decode(xdr, XDR_UNIT);
27 	if (!p)
28 		return false;
29 	*status = *p;
30 
31 	return true;
32 }
33 
34 static inline bool
svcxdr_encode_stats(struct xdr_stream * xdr,__be32 status)35 svcxdr_encode_stats(struct xdr_stream *xdr, __be32 status)
36 {
37 	__be32 *p;
38 
39 	p = xdr_reserve_space(xdr, XDR_UNIT);
40 	if (!p)
41 		return false;
42 	*p = status;
43 
44 	return true;
45 }
46 
47 static inline bool
svcxdr_decode_string(struct xdr_stream * xdr,char ** data,unsigned int * data_len)48 svcxdr_decode_string(struct xdr_stream *xdr, char **data, unsigned int *data_len)
49 {
50 	__be32 *p;
51 	u32 len;
52 
53 	if (xdr_stream_decode_u32(xdr, &len) < 0)
54 		return false;
55 	if (len > NLM_MAXSTRLEN)
56 		return false;
57 	p = xdr_inline_decode(xdr, len);
58 	if (!p)
59 		return false;
60 	*data_len = len;
61 	*data = (char *)p;
62 
63 	return true;
64 }
65 
66 /*
67  * NLM cookies are defined by specification to be a variable-length
68  * XDR opaque no longer than 1024 bytes. However, this implementation
69  * limits their length to 32 bytes, and treats zero-length cookies
70  * specially.
71  */
72 static inline bool
svcxdr_decode_cookie(struct xdr_stream * xdr,struct nlm_cookie * cookie)73 svcxdr_decode_cookie(struct xdr_stream *xdr, struct nlm_cookie *cookie)
74 {
75 	__be32 *p;
76 	u32 len;
77 
78 	if (xdr_stream_decode_u32(xdr, &len) < 0)
79 		return false;
80 	if (len > NLM_MAXCOOKIELEN)
81 		return false;
82 	if (!len)
83 		goto out_hpux;
84 
85 	p = xdr_inline_decode(xdr, len);
86 	if (!p)
87 		return false;
88 	cookie->len = len;
89 	memcpy(cookie->data, p, len);
90 
91 	return true;
92 
93 	/* apparently HPUX can return empty cookies */
94 out_hpux:
95 	cookie->len = 4;
96 	memset(cookie->data, 0, 4);
97 	return true;
98 }
99 
100 static inline bool
svcxdr_encode_cookie(struct xdr_stream * xdr,const struct nlm_cookie * cookie)101 svcxdr_encode_cookie(struct xdr_stream *xdr, const struct nlm_cookie *cookie)
102 {
103 	__be32 *p;
104 
105 	if (xdr_stream_encode_u32(xdr, cookie->len) < 0)
106 		return false;
107 	p = xdr_reserve_space(xdr, cookie->len);
108 	if (!p)
109 		return false;
110 	memcpy(p, cookie->data, cookie->len);
111 
112 	return true;
113 }
114 
115 static inline bool
svcxdr_decode_owner(struct xdr_stream * xdr,struct xdr_netobj * obj)116 svcxdr_decode_owner(struct xdr_stream *xdr, struct xdr_netobj *obj)
117 {
118 	__be32 *p;
119 	u32 len;
120 
121 	if (xdr_stream_decode_u32(xdr, &len) < 0)
122 		return false;
123 	if (len > XDR_MAX_NETOBJ)
124 		return false;
125 	p = xdr_inline_decode(xdr, len);
126 	if (!p)
127 		return false;
128 	obj->len = len;
129 	obj->data = (u8 *)p;
130 
131 	return true;
132 }
133 
134 static inline bool
svcxdr_encode_owner(struct xdr_stream * xdr,const struct xdr_netobj * obj)135 svcxdr_encode_owner(struct xdr_stream *xdr, const struct xdr_netobj *obj)
136 {
137 	if (obj->len > XDR_MAX_NETOBJ)
138 		return false;
139 	return xdr_stream_encode_opaque(xdr, obj->data, obj->len) > 0;
140 }
141 
142 #endif /* _LOCKD_SVCXDR_H_ */
143