1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
/* SPDX-License-Identifier: BSD-3-Clause */
/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)mbuf.h 8.3 (Berkeley) 1/21/94
* mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp
*/
#ifndef MBUF_H
#define MBUF_H
/*
* Macros for type conversion
* mtod(m,t) - convert mbuf pointer to data pointer of correct type
*/
#define mtod(m, t) ((t)(m)->m_data)
/* XXX About mbufs for slirp:
* Only one mbuf is ever used in a chain, for each "cell" of data.
* m_nextpkt points to the next packet, if fragmented.
* If the data is too large, the M_EXT is used, and a larger block
* is alloced. Therefore, m_free[m] must check for M_EXT and if set
* free the m_ext. This is inefficient memory-wise, but who cares.
*/
/*
* mbufs allow to have a gap between the start of the allocated buffer (m_ext if
* M_EXT is set, m_dat otherwise) and the in-use data:
*
* |--gapsize----->|---m_len------->
* |----------m_size------------------------------>
* |----M_ROOM-------------------->
* |-M_FREEROOM-->
*
* ^ ^ ^
* m_dat/m_ext m_data end of buffer
*/
/*
* How much room is in the mbuf, from m_data to the end of the mbuf
*/
#define M_ROOM(m) \
((m->m_flags & M_EXT) ? (((m)->m_ext + (m)->m_size) - (m)->m_data) : \
(((m)->m_dat + (m)->m_size) - (m)->m_data))
/*
* How much free room there is
*/
#define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
/*
* How much free room there is before m_data
*/
#define M_ROOMBEFORE(m) \
(((m)->m_flags & M_EXT) ? (m)->m_data - (m)->m_ext \
: (m)->m_data - (m)->m_dat)
struct mbuf {
/* XXX should union some of these! */
/* header at beginning of each mbuf: */
struct mbuf *m_next; /* Linked list of mbufs */
struct mbuf *m_prev;
struct mbuf *m_nextpkt; /* Next packet in queue/record */
struct mbuf *m_prevpkt; /* Flags aren't used in the output queue */
int m_flags; /* Misc flags */
int m_size; /* Size of mbuf, from m_dat or m_ext */
struct socket *m_so;
char *m_data; /* Current location of data */
int m_len; /* Amount of data in this mbuf, from m_data */
Slirp *slirp;
bool resolution_requested;
uint64_t expiration_date;
char *m_ext;
/* start of dynamic buffer area, must be last element */
char m_dat[];
};
#define ifq_prev m_prev
#define ifq_next m_next
#define ifs_prev m_prevpkt
#define ifs_next m_nextpkt
#define ifq_so m_so
#define M_EXT 0x01 /* m_ext points to more (malloced) data */
#define M_FREELIST 0x02 /* mbuf is on free list */
#define M_USEDLIST 0x04 /* XXX mbuf is on used list (for dtom()) */
#define M_DOFREE \
0x08 /* when m_free is called on the mbuf, free() \
* it rather than putting it on the free list */
void m_init(Slirp *);
void m_cleanup(Slirp *slirp);
struct mbuf *m_get(Slirp *);
void m_free(struct mbuf *);
void m_cat(register struct mbuf *, register struct mbuf *);
void m_inc(struct mbuf *, int);
void m_adj(struct mbuf *, int);
int m_copy(struct mbuf *, struct mbuf *, int, int);
struct mbuf *m_dup(Slirp *slirp, struct mbuf *m, bool copy_header, size_t header_size);
struct mbuf *dtom(Slirp *, void *);
static inline void ifs_init(struct mbuf *ifm)
{
ifm->ifs_next = ifm->ifs_prev = ifm;
}
#ifdef DEBUG
# define MBUF_DEBUG 1
#else
# ifdef HAVE_VALGRIND
# include <valgrind/valgrind.h>
# define MBUF_DEBUG RUNNING_ON_VALGRIND
# else
# define MBUF_DEBUG 0
# endif
#endif
/*
* When a function is given an mbuf as well as the responsibility to free it, we
* want valgrind etc. to properly identify the new responsible for the
* free. Achieve this by making a new copy. For instance:
*
* f0(void) {
* struct mbuf *m = m_get(slirp);
* [...]
* switch (something) {
* case 1:
* f1(m);
* break;
* case 2:
* f2(m);
* break;
* [...]
* }
* }
*
* f1(struct mbuf *m) {
* M_DUP_DEBUG(m->slirp, m);
* [...]
* m_free(m); // but author of f1 might be forgetting this
* }
*
* f0 transfers the freeing responsibility to f1, f2, etc. Without the
* M_DUP_DEBUG call in f1, valgrind would tell us that it is f0 where the buffer
* was allocated, but it's difficult to know whether a leak is actually in f0,
* or in f1, or in f2, etc. Duplicating the mbuf in M_DUP_DEBUG each time the
* responsibility is transferred allows to immediately know where the leak
* actually is.
*/
#define M_DUP_DEBUG(slirp, m, copy_header, header_size) do { \
if (MBUF_DEBUG) { \
struct mbuf *__n; \
__n = m_dup((slirp), (m), (copy_header), (header_size)); \
m_free(m); \
(m) = __n; \
} else { \
(void) (slirp); (void) (copy_header); \
g_assert(M_ROOMBEFORE(m) >= (header_size)); \
} \
} while(0)
#endif
|