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
|
/*
* Copyright (c) 1995 Danny Gasparovski.
*
* Please read the file COPYRIGHT for the
* terms and conditions of the copyright.
*/
#include "slirp.h"
static void sbappendsb(struct sbuf *sb, struct mbuf *m);
void
sbfree(struct sbuf *sb)
{
free(sb->sb_data);
}
bool
sbdrop(struct sbuf *sb, int num)
{
int limit = sb->sb_datalen / 2;
/*
* We can only drop how much we have
* This should never succeed
*/
if(num > sb->sb_cc)
num = sb->sb_cc;
sb->sb_cc -= num;
sb->sb_rptr += num;
if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)
sb->sb_rptr -= sb->sb_datalen;
if (sb->sb_cc < limit && sb->sb_cc + num >= limit) {
return true;
}
return false;
}
void
sbreserve(struct sbuf *sb, int size)
{
if (sb->sb_data) {
/* Already alloced, realloc if necessary */
if (sb->sb_datalen != size) {
sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);
sb->sb_cc = 0;
if (sb->sb_wptr)
sb->sb_datalen = size;
else
sb->sb_datalen = 0;
}
} else {
sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);
sb->sb_cc = 0;
if (sb->sb_wptr)
sb->sb_datalen = size;
else
sb->sb_datalen = 0;
}
}
/*
* Try and write() to the socket, whatever doesn't get written
* append to the buffer... for a host with a fast net connection,
* this prevents an unnecessary copy of the data
* (the socket is non-blocking, so we won't hang)
*/
void
sbappend(struct socket *so, struct mbuf *m)
{
int ret = 0;
DEBUG_CALL("sbappend");
DEBUG_ARG("so = %p", so);
DEBUG_ARG("m = %p", m);
DEBUG_ARG("m->m_len = %d", m->m_len);
/* Shouldn't happen, but... e.g. foreign host closes connection */
if (m->m_len <= 0) {
m_free(m);
return;
}
/*
* If there is urgent data, call sosendoob
* if not all was sent, sowrite will take care of the rest
* (The rest of this function is just an optimisation)
*/
if (so->so_urgc) {
sbappendsb(&so->so_rcv, m);
m_free(m);
(void)sosendoob(so);
return;
}
/*
* We only write if there's nothing in the buffer,
* ottherwise it'll arrive out of order, and hence corrupt
*/
if (!so->so_rcv.sb_cc)
ret = slirp_send(so, m->m_data, m->m_len, 0);
if (ret <= 0) {
/*
* Nothing was written
* It's possible that the socket has closed, but
* we don't need to check because if it has closed,
* it will be detected in the normal way by soread()
*/
sbappendsb(&so->so_rcv, m);
} else if (ret != m->m_len) {
/*
* Something was written, but not everything..
* sbappendsb the rest
*/
m->m_len -= ret;
m->m_data += ret;
sbappendsb(&so->so_rcv, m);
} /* else */
/* Whatever happened, we free the mbuf */
m_free(m);
}
/*
* Copy the data from m into sb
* The caller is responsible to make sure there's enough room
*/
static void
sbappendsb(struct sbuf *sb, struct mbuf *m)
{
int len, n, nn;
len = m->m_len;
if (sb->sb_wptr < sb->sb_rptr) {
n = sb->sb_rptr - sb->sb_wptr;
if (n > len) n = len;
memcpy(sb->sb_wptr, m->m_data, n);
} else {
/* Do the right edge first */
n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;
if (n > len) n = len;
memcpy(sb->sb_wptr, m->m_data, n);
len -= n;
if (len) {
/* Now the left edge */
nn = sb->sb_rptr - sb->sb_data;
if (nn > len) nn = len;
memcpy(sb->sb_data,m->m_data+n,nn);
n += nn;
}
}
sb->sb_cc += n;
sb->sb_wptr += n;
if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)
sb->sb_wptr -= sb->sb_datalen;
}
/*
* Copy data from sbuf to a normal, straight buffer
* Don't update the sbuf rptr, this will be
* done in sbdrop when the data is acked
*/
void
sbcopy(struct sbuf *sb, int off, int len, char *to)
{
char *from;
from = sb->sb_rptr + off;
if (from >= sb->sb_data + sb->sb_datalen)
from -= sb->sb_datalen;
if (from < sb->sb_wptr) {
if (len > sb->sb_cc) len = sb->sb_cc;
memcpy(to,from,len);
} else {
/* re-use off */
off = (sb->sb_data + sb->sb_datalen) - from;
if (off > len) off = len;
memcpy(to,from,off);
len -= off;
if (len)
memcpy(to+off,sb->sb_data,len);
}
}
|
