xref: /freebsd/sys/fs/nfs/nfsm_subs.h (revision af23369a6deaaeb612ab266eb88b8bb8d560c322)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Rick Macklem at The University of Guelph.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * $FreeBSD$
35  */
36 
37 #ifndef _NFS_NFSM_SUBS_H_
38 #define	_NFS_NFSM_SUBS_H_
39 
40 /*
41  * These macros do strange and peculiar things to mbuf chains for
42  * the assistance of the nfs code. To attempt to use them for any
43  * other purpose will be dangerous. (they make weird assumptions)
44  */
45 
46 /*
47  * First define what the actual subs. return
48  */
49 #define	NFSM_DATAP(m, s)	(m)->m_data += (s)
50 
51 /*
52  * Now for the macros that do the simple stuff and call the functions
53  * for the hard stuff.
54  * They use fields in struct nfsrv_descript to handle the mbuf queues.
55  * Replace most of the macro with an inline function, to minimize
56  * the machine code. The inline functions in lower case can be called
57  * directly, bypassing the macro.
58  */
59 static __inline void *
60 nfsm_build(struct nfsrv_descript *nd, int siz)
61 {
62 	void *retp;
63 	struct mbuf *mb2;
64 
65 	if ((nd->nd_flag & ND_EXTPG) == 0 &&
66 	    siz > M_TRAILINGSPACE(nd->nd_mb)) {
67 		NFSMCLGET(mb2, M_NOWAIT);
68 		if (siz > MLEN)
69 			panic("build > MLEN");
70 		mb2->m_len = 0;
71 		nd->nd_bpos = mtod(mb2, char *);
72 		nd->nd_mb->m_next = mb2;
73 		nd->nd_mb = mb2;
74 	} else if ((nd->nd_flag & ND_EXTPG) != 0) {
75 		if (siz > nd->nd_bextpgsiz) {
76 			mb2 = mb_alloc_ext_plus_pages(PAGE_SIZE, M_WAITOK);
77 			nd->nd_bpos = (char *)(void *)
78 			    PHYS_TO_DMAP(mb2->m_epg_pa[0]);
79 			nd->nd_bextpg = 0;
80 			nd->nd_bextpgsiz = PAGE_SIZE - siz;
81 			nd->nd_mb->m_next = mb2;
82 			nd->nd_mb = mb2;
83 		} else
84 			nd->nd_bextpgsiz -= siz;
85 		nd->nd_mb->m_epg_last_len += siz;
86 	}
87 	retp = (void *)(nd->nd_bpos);
88 	nd->nd_mb->m_len += siz;
89 	nd->nd_bpos += siz;
90 	return (retp);
91 }
92 
93 #define	NFSM_BUILD(a, c, s)	((a) = (c)nfsm_build(nd, (s)))
94 
95 static __inline void *
96 nfsm_dissect(struct nfsrv_descript *nd, int siz)
97 {
98 	int tt1;
99 	void *retp;
100 
101 	tt1 = mtod(nd->nd_md, caddr_t) + nd->nd_md->m_len - nd->nd_dpos;
102 	if (tt1 >= siz) {
103 		retp = (void *)nd->nd_dpos;
104 		nd->nd_dpos += siz;
105 	} else {
106 		retp = nfsm_dissct(nd, siz, M_WAITOK);
107 	}
108 	return (retp);
109 }
110 
111 static __inline void *
112 nfsm_dissect_nonblock(struct nfsrv_descript *nd, int siz)
113 {
114 	int tt1;
115 	void *retp;
116 
117 	tt1 = mtod(nd->nd_md, caddr_t) + nd->nd_md->m_len - nd->nd_dpos;
118 	if (tt1 >= siz) {
119 		retp = (void *)nd->nd_dpos;
120 		nd->nd_dpos += siz;
121 	} else {
122 		retp = nfsm_dissct(nd, siz, M_NOWAIT);
123 	}
124 	return (retp);
125 }
126 
127 #define	NFSM_DISSECT(a, c, s) 						\
128 	do {								\
129 		(a) = (c)nfsm_dissect(nd, (s));	 			\
130 		if ((a) == NULL) { 					\
131 			error = EBADRPC; 				\
132 			goto nfsmout; 					\
133 		}							\
134 	} while (0)
135 
136 #define	NFSM_DISSECT_NONBLOCK(a, c, s) 					\
137 	do {								\
138 		(a) = (c)nfsm_dissect_nonblock(nd, (s));		\
139 		if ((a) == NULL) { 					\
140 			error = EBADRPC; 				\
141 			goto nfsmout; 					\
142 		}							\
143 	} while (0)
144 
145 #define	NFSM_STRSIZ(s, m)  						\
146 	do {								\
147 		tl = (u_int32_t *)nfsm_dissect(nd, NFSX_UNSIGNED);	\
148 		if (!tl || ((s) = fxdr_unsigned(int32_t, *tl)) > (m)) { \
149 			error = EBADRPC; 				\
150 			goto nfsmout; 					\
151 		}							\
152 	} while (0)
153 
154 #define	NFSM_RNDUP(a)	(((a)+3)&(~0x3))
155 
156 #endif	/* _NFS_NFSM_SUBS_H_ */
157