xref: /freebsd/sys/fs/nfs/nfsm_subs.h (revision 2e3f49888ec8851bafb22011533217487764fdb0)
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 
35 #ifndef _NFS_NFSM_SUBS_H_
36 #define	_NFS_NFSM_SUBS_H_
37 
38 /*
39  * These macros do strange and peculiar things to mbuf chains for
40  * the assistance of the nfs code. To attempt to use them for any
41  * other purpose will be dangerous. (they make weird assumptions)
42  */
43 
44 /*
45  * First define what the actual subs. return
46  */
47 #define	NFSM_DATAP(m, s)	(m)->m_data += (s)
48 
49 /*
50  * Now for the macros that do the simple stuff and call the functions
51  * for the hard stuff.
52  * They use fields in struct nfsrv_descript to handle the mbuf queues.
53  * Replace most of the macro with an inline function, to minimize
54  * the machine code. The inline functions in lower case can be called
55  * directly, bypassing the macro.
56  */
57 static __inline void *
58 nfsm_build(struct nfsrv_descript *nd, int siz)
59 {
60 	void *retp;
61 	struct mbuf *mb2;
62 
63 	if ((nd->nd_flag & ND_EXTPG) == 0 &&
64 	    siz > M_TRAILINGSPACE(nd->nd_mb)) {
65 		NFSMCLGET(mb2, M_NOWAIT);
66 		if (siz > MLEN)
67 			panic("build > MLEN");
68 		mb2->m_len = 0;
69 		nd->nd_bpos = mtod(mb2, char *);
70 		nd->nd_mb->m_next = mb2;
71 		nd->nd_mb = mb2;
72 	} else if ((nd->nd_flag & ND_EXTPG) != 0) {
73 		if (siz > nd->nd_bextpgsiz) {
74 			mb2 = mb_alloc_ext_plus_pages(PAGE_SIZE, M_WAITOK);
75 			nd->nd_bpos = (char *)(void *)
76 			    PHYS_TO_DMAP(mb2->m_epg_pa[0]);
77 			nd->nd_bextpg = 0;
78 			nd->nd_bextpgsiz = PAGE_SIZE - siz;
79 			nd->nd_mb->m_next = mb2;
80 			nd->nd_mb = mb2;
81 		} else
82 			nd->nd_bextpgsiz -= siz;
83 		nd->nd_mb->m_epg_last_len += siz;
84 	}
85 	retp = (void *)(nd->nd_bpos);
86 	nd->nd_mb->m_len += siz;
87 	nd->nd_bpos += siz;
88 	return (retp);
89 }
90 
91 #define	NFSM_BUILD(a, c, s)	((a) = (c)nfsm_build(nd, (s)))
92 
93 static __inline void *
94 nfsm_dissect(struct nfsrv_descript *nd, int siz)
95 {
96 	int tt1;
97 	void *retp;
98 
99 	tt1 = mtod(nd->nd_md, caddr_t) + nd->nd_md->m_len - nd->nd_dpos;
100 	if (tt1 >= siz) {
101 		retp = (void *)nd->nd_dpos;
102 		nd->nd_dpos += siz;
103 	} else {
104 		retp = nfsm_dissct(nd, siz, M_WAITOK);
105 	}
106 	return (retp);
107 }
108 
109 static __inline void *
110 nfsm_dissect_nonblock(struct nfsrv_descript *nd, int siz)
111 {
112 	int tt1;
113 	void *retp;
114 
115 	tt1 = mtod(nd->nd_md, caddr_t) + nd->nd_md->m_len - nd->nd_dpos;
116 	if (tt1 >= siz) {
117 		retp = (void *)nd->nd_dpos;
118 		nd->nd_dpos += siz;
119 	} else {
120 		retp = nfsm_dissct(nd, siz, M_NOWAIT);
121 	}
122 	return (retp);
123 }
124 
125 #define	NFSM_DISSECT(a, c, s) 						\
126 	do {								\
127 		(a) = (c)nfsm_dissect(nd, (s));	 			\
128 		if ((a) == NULL) { 					\
129 			error = EBADRPC; 				\
130 			goto nfsmout; 					\
131 		}							\
132 	} while (0)
133 
134 #define	NFSM_DISSECT_NONBLOCK(a, c, s) 					\
135 	do {								\
136 		(a) = (c)nfsm_dissect_nonblock(nd, (s));		\
137 		if ((a) == NULL) { 					\
138 			error = EBADRPC; 				\
139 			goto nfsmout; 					\
140 		}							\
141 	} while (0)
142 
143 #define	NFSM_STRSIZ(s, m)  						\
144 	do {								\
145 		tl = (u_int32_t *)nfsm_dissect(nd, NFSX_UNSIGNED);	\
146 		if (!tl || ((s) = fxdr_unsigned(int32_t, *tl)) > (m)) { \
147 			error = EBADRPC; 				\
148 			goto nfsmout; 					\
149 		}							\
150 	} while (0)
151 
152 #define	NFSM_RNDUP(a)	(((a)+3)&(~0x3))
153 
154 #endif	/* _NFS_NFSM_SUBS_H_ */
155