fs/lockd/svcxdr.h

   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
  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
  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
  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
  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
 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
 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
 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_ */