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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* Copyright (c) 1995 Danny Gasparovski
*
* Please read the file COPYRIGHT for the
* terms and conditions of the copyright.
*/
/*
* mbuf's in SLiRP are much simpler than the real mbufs in
* FreeBSD. They are fixed size, determined by the MTU,
* so that one whole packet can fit. Mbuf's cannot be
* chained together. If there's more data than the mbuf
* could hold, an external g_malloced buffer is pointed to
* by m_ext (and the data pointers) and M_EXT is set in
* the flags
*/
#include "qemu/osdep.h"
#include "slirp.h"
#define MBUF_THRESH 30
/*
* Find a nice value for msize
*/
#define SLIRP_MSIZE\
(offsetof(struct mbuf, m_dat) + IF_MAXLINKHDR + TCPIPHDR_DELTA + IF_MTU)
void
m_init(Slirp *slirp)
{
slirp->m_freelist.qh_link = slirp->m_freelist.qh_rlink = &slirp->m_freelist;
slirp->m_usedlist.qh_link = slirp->m_usedlist.qh_rlink = &slirp->m_usedlist;
}
void m_cleanup(Slirp *slirp)
{
struct mbuf *m, *next;
m = (struct mbuf *) slirp->m_usedlist.qh_link;
while ((struct quehead *) m != &slirp->m_usedlist) {
next = m->m_next;
if (m->m_flags & M_EXT) {
g_free(m->m_ext);
}
g_free(m);
m = next;
}
m = (struct mbuf *) slirp->m_freelist.qh_link;
while ((struct quehead *) m != &slirp->m_freelist) {
next = m->m_next;
g_free(m);
m = next;
}
}
/*
* Get an mbuf from the free list, if there are none
* allocate one
*
* Because fragmentation can occur if we alloc new mbufs and
* free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
* which tells m_free to actually g_free() it
*/
struct mbuf *
m_get(Slirp *slirp)
{
register struct mbuf *m;
int flags = 0;
DEBUG_CALL("m_get");
if (slirp->m_freelist.qh_link == &slirp->m_freelist) {
m = g_malloc(SLIRP_MSIZE);
slirp->mbuf_alloced++;
if (slirp->mbuf_alloced > MBUF_THRESH)
flags = M_DOFREE;
m->slirp = slirp;
} else {
m = (struct mbuf *) slirp->m_freelist.qh_link;
remque(m);
}
/* Insert it in the used list */
insque(m,&slirp->m_usedlist);
m->m_flags = (flags | M_USEDLIST);
/* Initialise it */
m->m_size = SLIRP_MSIZE - offsetof(struct mbuf, m_dat);
m->m_data = m->m_dat;
m->m_len = 0;
m->m_nextpkt = NULL;
m->m_prevpkt = NULL;
m->resolution_requested = false;
m->expiration_date = (uint64_t)-1;
DEBUG_ARG("m = %p", m);
return m;
}
void
m_free(struct mbuf *m)
{
DEBUG_CALL("m_free");
DEBUG_ARG("m = %p", m);
if(m) {
/* Remove from m_usedlist */
if (m->m_flags & M_USEDLIST)
remque(m);
/* If it's M_EXT, free() it */
if (m->m_flags & M_EXT) {
g_free(m->m_ext);
}
/*
* Either free() it or put it on the free list
*/
if (m->m_flags & M_DOFREE) {
m->slirp->mbuf_alloced--;
g_free(m);
} else if ((m->m_flags & M_FREELIST) == 0) {
insque(m,&m->slirp->m_freelist);
m->m_flags = M_FREELIST; /* Clobber other flags */
}
} /* if(m) */
}
/*
* Copy data from one mbuf to the end of
* the other.. if result is too big for one mbuf, allocate
* an M_EXT data segment
*/
void
m_cat(struct mbuf *m, struct mbuf *n)
{
/*
* If there's no room, realloc
*/
if (M_FREEROOM(m) < n->m_len)
m_inc(m, m->m_len + n->m_len);
memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
m->m_len += n->m_len;
m_free(n);
}
/* make m 'size' bytes large from m_data */
void
m_inc(struct mbuf *m, int size)
{
int gapsize;
/* some compilers throw up on gotos. This one we can fake. */
if (M_ROOM(m) > size) {
return;
}
if (m->m_flags & M_EXT) {
gapsize = m->m_data - m->m_ext;
m->m_ext = g_realloc(m->m_ext, size + gapsize);
} else {
gapsize = m->m_data - m->m_dat;
m->m_ext = g_malloc(size + gapsize);
memcpy(m->m_ext, m->m_dat, m->m_size);
m->m_flags |= M_EXT;
}
m->m_data = m->m_ext + gapsize;
m->m_size = size + gapsize;
}
void
m_adj(struct mbuf *m, int len)
{
if (m == NULL)
return;
if (len >= 0) {
/* Trim from head */
m->m_data += len;
m->m_len -= len;
} else {
/* Trim from tail */
len = -len;
m->m_len -= len;
}
}
/*
* Copy len bytes from m, starting off bytes into n
*/
int
m_copy(struct mbuf *n, struct mbuf *m, int off, int len)
{
if (len > M_FREEROOM(n))
return -1;
memcpy((n->m_data + n->m_len), (m->m_data + off), len);
n->m_len += len;
return 0;
}
/*
* Given a pointer into an mbuf, return the mbuf
* XXX This is a kludge, I should eliminate the need for it
* Fortunately, it's not used often
*/
struct mbuf *
dtom(Slirp *slirp, void *dat)
{
struct mbuf *m;
DEBUG_CALL("dtom");
DEBUG_ARG("dat = %p", dat);
/* bug corrected for M_EXT buffers */
for (m = (struct mbuf *) slirp->m_usedlist.qh_link;
(struct quehead *) m != &slirp->m_usedlist;
m = m->m_next) {
if (m->m_flags & M_EXT) {
if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) )
return m;
} else {
if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) )
return m;
}
}
DEBUG_ERROR("dtom failed");
return (struct mbuf *)0;
}
|
