root / slirp / mbuf.c @ a8d3431a
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1 | f0cbd3ec | bellard | /*
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2 | f0cbd3ec | bellard | * Copyright (c) 1995 Danny Gasparovski
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3 | f0cbd3ec | bellard | *
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4 | f0cbd3ec | bellard | * Please read the file COPYRIGHT for the
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5 | f0cbd3ec | bellard | * terms and conditions of the copyright.
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6 | f0cbd3ec | bellard | */
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7 | f0cbd3ec | bellard | |
8 | f0cbd3ec | bellard | /*
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9 | f0cbd3ec | bellard | * mbuf's in SLiRP are much simpler than the real mbufs in
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10 | f0cbd3ec | bellard | * FreeBSD. They are fixed size, determined by the MTU,
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11 | f0cbd3ec | bellard | * so that one whole packet can fit. Mbuf's cannot be
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12 | f0cbd3ec | bellard | * chained together. If there's more data than the mbuf
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13 | f0cbd3ec | bellard | * could hold, an external malloced buffer is pointed to
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14 | f0cbd3ec | bellard | * by m_ext (and the data pointers) and M_EXT is set in
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15 | f0cbd3ec | bellard | * the flags
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16 | f0cbd3ec | bellard | */
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17 | f0cbd3ec | bellard | |
18 | f0cbd3ec | bellard | #include <slirp.h> |
19 | f0cbd3ec | bellard | |
20 | f0cbd3ec | bellard | struct mbuf *mbutl;
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21 | f0cbd3ec | bellard | char *mclrefcnt;
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22 | f0cbd3ec | bellard | int mbuf_alloced = 0; |
23 | f0cbd3ec | bellard | struct mbuf m_freelist, m_usedlist;
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24 | f0cbd3ec | bellard | int mbuf_thresh = 30; |
25 | f0cbd3ec | bellard | int mbuf_max = 0; |
26 | f0cbd3ec | bellard | int msize;
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27 | f0cbd3ec | bellard | |
28 | f0cbd3ec | bellard | void
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29 | f0cbd3ec | bellard | m_init() |
30 | f0cbd3ec | bellard | { |
31 | f0cbd3ec | bellard | m_freelist.m_next = m_freelist.m_prev = &m_freelist; |
32 | f0cbd3ec | bellard | m_usedlist.m_next = m_usedlist.m_prev = &m_usedlist; |
33 | f0cbd3ec | bellard | msize_init(); |
34 | f0cbd3ec | bellard | } |
35 | f0cbd3ec | bellard | |
36 | f0cbd3ec | bellard | void
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37 | f0cbd3ec | bellard | msize_init() |
38 | f0cbd3ec | bellard | { |
39 | f0cbd3ec | bellard | /*
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40 | f0cbd3ec | bellard | * Find a nice value for msize
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41 | f0cbd3ec | bellard | * XXX if_maxlinkhdr already in mtu
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42 | f0cbd3ec | bellard | */
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43 | f0cbd3ec | bellard | msize = (if_mtu>if_mru?if_mtu:if_mru) + |
44 | f0cbd3ec | bellard | if_maxlinkhdr + sizeof(struct m_hdr ) + 6; |
45 | f0cbd3ec | bellard | } |
46 | f0cbd3ec | bellard | |
47 | f0cbd3ec | bellard | /*
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48 | f0cbd3ec | bellard | * Get an mbuf from the free list, if there are none
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49 | f0cbd3ec | bellard | * malloc one
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50 | f0cbd3ec | bellard | *
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51 | f0cbd3ec | bellard | * Because fragmentation can occur if we alloc new mbufs and
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52 | f0cbd3ec | bellard | * free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
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53 | f0cbd3ec | bellard | * which tells m_free to actually free() it
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54 | f0cbd3ec | bellard | */
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55 | f0cbd3ec | bellard | struct mbuf *
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56 | f0cbd3ec | bellard | m_get() |
57 | f0cbd3ec | bellard | { |
58 | f0cbd3ec | bellard | register struct mbuf *m; |
59 | f0cbd3ec | bellard | int flags = 0; |
60 | f0cbd3ec | bellard | |
61 | f0cbd3ec | bellard | DEBUG_CALL("m_get");
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62 | f0cbd3ec | bellard | |
63 | f0cbd3ec | bellard | if (m_freelist.m_next == &m_freelist) {
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64 | f0cbd3ec | bellard | m = (struct mbuf *)malloc(msize);
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65 | f0cbd3ec | bellard | if (m == NULL) goto end_error; |
66 | f0cbd3ec | bellard | mbuf_alloced++; |
67 | f0cbd3ec | bellard | if (mbuf_alloced > mbuf_thresh)
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68 | f0cbd3ec | bellard | flags = M_DOFREE; |
69 | f0cbd3ec | bellard | if (mbuf_alloced > mbuf_max)
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70 | f0cbd3ec | bellard | mbuf_max = mbuf_alloced; |
71 | f0cbd3ec | bellard | } else {
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72 | f0cbd3ec | bellard | m = m_freelist.m_next; |
73 | f0cbd3ec | bellard | remque(m); |
74 | f0cbd3ec | bellard | } |
75 | f0cbd3ec | bellard | |
76 | f0cbd3ec | bellard | /* Insert it in the used list */
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77 | f0cbd3ec | bellard | insque(m,&m_usedlist); |
78 | f0cbd3ec | bellard | m->m_flags = (flags | M_USEDLIST); |
79 | f0cbd3ec | bellard | |
80 | f0cbd3ec | bellard | /* Initialise it */
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81 | f0cbd3ec | bellard | m->m_size = msize - sizeof(struct m_hdr); |
82 | f0cbd3ec | bellard | m->m_data = m->m_dat; |
83 | f0cbd3ec | bellard | m->m_len = 0;
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84 | f0cbd3ec | bellard | m->m_nextpkt = 0;
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85 | f0cbd3ec | bellard | m->m_prevpkt = 0;
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86 | f0cbd3ec | bellard | end_error:
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87 | f0cbd3ec | bellard | DEBUG_ARG("m = %lx", (long )m); |
88 | f0cbd3ec | bellard | return m;
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89 | f0cbd3ec | bellard | } |
90 | f0cbd3ec | bellard | |
91 | f0cbd3ec | bellard | void
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92 | f0cbd3ec | bellard | m_free(m) |
93 | f0cbd3ec | bellard | struct mbuf *m;
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94 | f0cbd3ec | bellard | { |
95 | f0cbd3ec | bellard | |
96 | f0cbd3ec | bellard | DEBUG_CALL("m_free");
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97 | f0cbd3ec | bellard | DEBUG_ARG("m = %lx", (long )m); |
98 | f0cbd3ec | bellard | |
99 | f0cbd3ec | bellard | if(m) {
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100 | f0cbd3ec | bellard | /* Remove from m_usedlist */
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101 | f0cbd3ec | bellard | if (m->m_flags & M_USEDLIST)
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102 | f0cbd3ec | bellard | remque(m); |
103 | f0cbd3ec | bellard | |
104 | f0cbd3ec | bellard | /* If it's M_EXT, free() it */
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105 | f0cbd3ec | bellard | if (m->m_flags & M_EXT)
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106 | f0cbd3ec | bellard | free(m->m_ext); |
107 | f0cbd3ec | bellard | |
108 | f0cbd3ec | bellard | /*
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109 | f0cbd3ec | bellard | * Either free() it or put it on the free list
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110 | f0cbd3ec | bellard | */
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111 | f0cbd3ec | bellard | if (m->m_flags & M_DOFREE) {
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112 | f0cbd3ec | bellard | free(m); |
113 | f0cbd3ec | bellard | mbuf_alloced--; |
114 | f0cbd3ec | bellard | } else if ((m->m_flags & M_FREELIST) == 0) { |
115 | f0cbd3ec | bellard | insque(m,&m_freelist); |
116 | f0cbd3ec | bellard | m->m_flags = M_FREELIST; /* Clobber other flags */
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117 | f0cbd3ec | bellard | } |
118 | f0cbd3ec | bellard | } /* if(m) */
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119 | f0cbd3ec | bellard | } |
120 | f0cbd3ec | bellard | |
121 | f0cbd3ec | bellard | /*
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122 | f0cbd3ec | bellard | * Copy data from one mbuf to the end of
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123 | f0cbd3ec | bellard | * the other.. if result is too big for one mbuf, malloc()
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124 | f0cbd3ec | bellard | * an M_EXT data segment
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125 | f0cbd3ec | bellard | */
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126 | f0cbd3ec | bellard | void
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127 | f0cbd3ec | bellard | m_cat(m, n) |
128 | f0cbd3ec | bellard | register struct mbuf *m, *n; |
129 | f0cbd3ec | bellard | { |
130 | f0cbd3ec | bellard | /*
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131 | f0cbd3ec | bellard | * If there's no room, realloc
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132 | f0cbd3ec | bellard | */
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133 | f0cbd3ec | bellard | if (M_FREEROOM(m) < n->m_len)
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134 | f0cbd3ec | bellard | m_inc(m,m->m_size+MINCSIZE); |
135 | f0cbd3ec | bellard | |
136 | f0cbd3ec | bellard | memcpy(m->m_data+m->m_len, n->m_data, n->m_len); |
137 | f0cbd3ec | bellard | m->m_len += n->m_len; |
138 | f0cbd3ec | bellard | |
139 | f0cbd3ec | bellard | m_free(n); |
140 | f0cbd3ec | bellard | } |
141 | f0cbd3ec | bellard | |
142 | f0cbd3ec | bellard | |
143 | f0cbd3ec | bellard | /* make m size bytes large */
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144 | f0cbd3ec | bellard | void
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145 | f0cbd3ec | bellard | m_inc(m, size) |
146 | f0cbd3ec | bellard | struct mbuf *m;
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147 | f0cbd3ec | bellard | int size;
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148 | f0cbd3ec | bellard | { |
149 | f0cbd3ec | bellard | /* some compiles throw up on gotos. This one we can fake. */
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150 | f0cbd3ec | bellard | if(m->m_size>size) return; |
151 | f0cbd3ec | bellard | |
152 | f0cbd3ec | bellard | if (m->m_flags & M_EXT) {
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153 | f0cbd3ec | bellard | /* datasize = m->m_data - m->m_ext; */
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154 | f0cbd3ec | bellard | m->m_ext = (char *)realloc(m->m_ext,size);
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155 | f0cbd3ec | bellard | /* if (m->m_ext == NULL)
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156 | f0cbd3ec | bellard | * return (struct mbuf *)NULL;
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157 | f0cbd3ec | bellard | */
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158 | f0cbd3ec | bellard | /* m->m_data = m->m_ext + datasize; */
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159 | f0cbd3ec | bellard | } else {
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160 | f0cbd3ec | bellard | int datasize;
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161 | f0cbd3ec | bellard | char *dat;
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162 | f0cbd3ec | bellard | datasize = m->m_data - m->m_dat; |
163 | f0cbd3ec | bellard | dat = (char *)malloc(size);
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164 | f0cbd3ec | bellard | /* if (dat == NULL)
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165 | f0cbd3ec | bellard | * return (struct mbuf *)NULL;
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166 | f0cbd3ec | bellard | */
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167 | f0cbd3ec | bellard | memcpy(dat, m->m_dat, m->m_size); |
168 | f0cbd3ec | bellard | |
169 | f0cbd3ec | bellard | m->m_ext = dat; |
170 | f0cbd3ec | bellard | m->m_data = m->m_ext + datasize; |
171 | f0cbd3ec | bellard | m->m_flags |= M_EXT; |
172 | f0cbd3ec | bellard | } |
173 | f0cbd3ec | bellard | |
174 | f0cbd3ec | bellard | m->m_size = size; |
175 | f0cbd3ec | bellard | |
176 | f0cbd3ec | bellard | } |
177 | f0cbd3ec | bellard | |
178 | f0cbd3ec | bellard | |
179 | f0cbd3ec | bellard | |
180 | f0cbd3ec | bellard | void
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181 | f0cbd3ec | bellard | m_adj(m, len) |
182 | f0cbd3ec | bellard | struct mbuf *m;
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183 | f0cbd3ec | bellard | int len;
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184 | f0cbd3ec | bellard | { |
185 | f0cbd3ec | bellard | if (m == NULL) |
186 | f0cbd3ec | bellard | return;
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187 | f0cbd3ec | bellard | if (len >= 0) { |
188 | f0cbd3ec | bellard | /* Trim from head */
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189 | f0cbd3ec | bellard | m->m_data += len; |
190 | f0cbd3ec | bellard | m->m_len -= len; |
191 | f0cbd3ec | bellard | } else {
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192 | f0cbd3ec | bellard | /* Trim from tail */
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193 | f0cbd3ec | bellard | len = -len; |
194 | f0cbd3ec | bellard | m->m_len -= len; |
195 | f0cbd3ec | bellard | } |
196 | f0cbd3ec | bellard | } |
197 | f0cbd3ec | bellard | |
198 | f0cbd3ec | bellard | |
199 | f0cbd3ec | bellard | /*
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200 | f0cbd3ec | bellard | * Copy len bytes from m, starting off bytes into n
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201 | f0cbd3ec | bellard | */
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202 | f0cbd3ec | bellard | int
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203 | f0cbd3ec | bellard | m_copy(n, m, off, len) |
204 | f0cbd3ec | bellard | struct mbuf *n, *m;
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205 | f0cbd3ec | bellard | int off, len;
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206 | f0cbd3ec | bellard | { |
207 | f0cbd3ec | bellard | if (len > M_FREEROOM(n))
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208 | f0cbd3ec | bellard | return -1; |
209 | f0cbd3ec | bellard | |
210 | f0cbd3ec | bellard | memcpy((n->m_data + n->m_len), (m->m_data + off), len); |
211 | f0cbd3ec | bellard | n->m_len += len; |
212 | f0cbd3ec | bellard | return 0; |
213 | f0cbd3ec | bellard | } |
214 | f0cbd3ec | bellard | |
215 | f0cbd3ec | bellard | |
216 | f0cbd3ec | bellard | /*
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217 | f0cbd3ec | bellard | * Given a pointer into an mbuf, return the mbuf
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218 | f0cbd3ec | bellard | * XXX This is a kludge, I should eliminate the need for it
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219 | f0cbd3ec | bellard | * Fortunately, it's not used often
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220 | f0cbd3ec | bellard | */
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221 | f0cbd3ec | bellard | struct mbuf *
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222 | f0cbd3ec | bellard | dtom(dat) |
223 | f0cbd3ec | bellard | void *dat;
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224 | f0cbd3ec | bellard | { |
225 | f0cbd3ec | bellard | struct mbuf *m;
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226 | f0cbd3ec | bellard | |
227 | f0cbd3ec | bellard | DEBUG_CALL("dtom");
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228 | f0cbd3ec | bellard | DEBUG_ARG("dat = %lx", (long )dat); |
229 | f0cbd3ec | bellard | |
230 | f0cbd3ec | bellard | /* bug corrected for M_EXT buffers */
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231 | f0cbd3ec | bellard | for (m = m_usedlist.m_next; m != &m_usedlist; m = m->m_next) {
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232 | f0cbd3ec | bellard | if (m->m_flags & M_EXT) {
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233 | f0cbd3ec | bellard | if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) ) |
234 | f0cbd3ec | bellard | return m;
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235 | f0cbd3ec | bellard | } else {
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236 | f0cbd3ec | bellard | if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) ) |
237 | f0cbd3ec | bellard | return m;
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238 | f0cbd3ec | bellard | } |
239 | f0cbd3ec | bellard | } |
240 | f0cbd3ec | bellard | |
241 | f0cbd3ec | bellard | DEBUG_ERROR((dfd, "dtom failed"));
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242 | f0cbd3ec | bellard | |
243 | f0cbd3ec | bellard | return (struct mbuf *)0; |
244 | f0cbd3ec | bellard | } |