root / slirp / mbuf.c @ b5dc7732
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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 | 9634d903 | blueswir1 | #define MBUF_THRESH 30 |
25 | f0cbd3ec | bellard | int mbuf_max = 0; |
26 | 9634d903 | blueswir1 | |
27 | 9634d903 | blueswir1 | /*
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28 | 9634d903 | blueswir1 | * Find a nice value for msize
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29 | 9634d903 | blueswir1 | * XXX if_maxlinkhdr already in mtu
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30 | 9634d903 | blueswir1 | */
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31 | 9634d903 | blueswir1 | #define MSIZE (IF_MTU + IF_MAXLINKHDR + sizeof(struct m_hdr ) + 6) |
32 | f0cbd3ec | bellard | |
33 | f0cbd3ec | bellard | void
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34 | f0cbd3ec | bellard | m_init() |
35 | f0cbd3ec | bellard | { |
36 | f0cbd3ec | bellard | m_freelist.m_next = m_freelist.m_prev = &m_freelist; |
37 | f0cbd3ec | bellard | m_usedlist.m_next = m_usedlist.m_prev = &m_usedlist; |
38 | f0cbd3ec | bellard | } |
39 | f0cbd3ec | bellard | |
40 | f0cbd3ec | bellard | /*
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41 | f0cbd3ec | bellard | * Get an mbuf from the free list, if there are none
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42 | f0cbd3ec | bellard | * malloc one
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43 | 5fafdf24 | ths | *
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44 | f0cbd3ec | bellard | * Because fragmentation can occur if we alloc new mbufs and
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45 | f0cbd3ec | bellard | * free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
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46 | f0cbd3ec | bellard | * which tells m_free to actually free() it
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47 | f0cbd3ec | bellard | */
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48 | f0cbd3ec | bellard | struct mbuf *
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49 | f0cbd3ec | bellard | m_get() |
50 | f0cbd3ec | bellard | { |
51 | f0cbd3ec | bellard | register struct mbuf *m; |
52 | f0cbd3ec | bellard | int flags = 0; |
53 | 5fafdf24 | ths | |
54 | f0cbd3ec | bellard | DEBUG_CALL("m_get");
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55 | 5fafdf24 | ths | |
56 | f0cbd3ec | bellard | if (m_freelist.m_next == &m_freelist) {
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57 | 9634d903 | blueswir1 | m = (struct mbuf *)malloc(MSIZE);
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58 | f0cbd3ec | bellard | if (m == NULL) goto end_error; |
59 | f0cbd3ec | bellard | mbuf_alloced++; |
60 | 9634d903 | blueswir1 | if (mbuf_alloced > MBUF_THRESH)
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61 | f0cbd3ec | bellard | flags = M_DOFREE; |
62 | f0cbd3ec | bellard | if (mbuf_alloced > mbuf_max)
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63 | f0cbd3ec | bellard | mbuf_max = mbuf_alloced; |
64 | f0cbd3ec | bellard | } else {
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65 | f0cbd3ec | bellard | m = m_freelist.m_next; |
66 | f0cbd3ec | bellard | remque(m); |
67 | f0cbd3ec | bellard | } |
68 | 5fafdf24 | ths | |
69 | f0cbd3ec | bellard | /* Insert it in the used list */
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70 | f0cbd3ec | bellard | insque(m,&m_usedlist); |
71 | f0cbd3ec | bellard | m->m_flags = (flags | M_USEDLIST); |
72 | 5fafdf24 | ths | |
73 | f0cbd3ec | bellard | /* Initialise it */
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74 | 9634d903 | blueswir1 | m->m_size = MSIZE - sizeof(struct m_hdr); |
75 | f0cbd3ec | bellard | m->m_data = m->m_dat; |
76 | f0cbd3ec | bellard | m->m_len = 0;
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77 | f0cbd3ec | bellard | m->m_nextpkt = 0;
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78 | f0cbd3ec | bellard | m->m_prevpkt = 0;
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79 | f0cbd3ec | bellard | end_error:
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80 | f0cbd3ec | bellard | DEBUG_ARG("m = %lx", (long )m); |
81 | f0cbd3ec | bellard | return m;
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82 | f0cbd3ec | bellard | } |
83 | f0cbd3ec | bellard | |
84 | f0cbd3ec | bellard | void
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85 | f0cbd3ec | bellard | m_free(m) |
86 | f0cbd3ec | bellard | struct mbuf *m;
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87 | f0cbd3ec | bellard | { |
88 | 5fafdf24 | ths | |
89 | f0cbd3ec | bellard | DEBUG_CALL("m_free");
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90 | f0cbd3ec | bellard | DEBUG_ARG("m = %lx", (long )m); |
91 | 5fafdf24 | ths | |
92 | f0cbd3ec | bellard | if(m) {
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93 | f0cbd3ec | bellard | /* Remove from m_usedlist */
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94 | f0cbd3ec | bellard | if (m->m_flags & M_USEDLIST)
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95 | f0cbd3ec | bellard | remque(m); |
96 | 5fafdf24 | ths | |
97 | f0cbd3ec | bellard | /* If it's M_EXT, free() it */
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98 | f0cbd3ec | bellard | if (m->m_flags & M_EXT)
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99 | f0cbd3ec | bellard | free(m->m_ext); |
100 | f0cbd3ec | bellard | |
101 | f0cbd3ec | bellard | /*
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102 | f0cbd3ec | bellard | * Either free() it or put it on the free list
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103 | f0cbd3ec | bellard | */
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104 | f0cbd3ec | bellard | if (m->m_flags & M_DOFREE) {
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105 | f0cbd3ec | bellard | free(m); |
106 | f0cbd3ec | bellard | mbuf_alloced--; |
107 | f0cbd3ec | bellard | } else if ((m->m_flags & M_FREELIST) == 0) { |
108 | f0cbd3ec | bellard | insque(m,&m_freelist); |
109 | f0cbd3ec | bellard | m->m_flags = M_FREELIST; /* Clobber other flags */
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110 | f0cbd3ec | bellard | } |
111 | f0cbd3ec | bellard | } /* if(m) */
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112 | f0cbd3ec | bellard | } |
113 | f0cbd3ec | bellard | |
114 | f0cbd3ec | bellard | /*
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115 | f0cbd3ec | bellard | * Copy data from one mbuf to the end of
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116 | f0cbd3ec | bellard | * the other.. if result is too big for one mbuf, malloc()
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117 | f0cbd3ec | bellard | * an M_EXT data segment
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118 | f0cbd3ec | bellard | */
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119 | f0cbd3ec | bellard | void
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120 | f0cbd3ec | bellard | m_cat(m, n) |
121 | f0cbd3ec | bellard | register struct mbuf *m, *n; |
122 | f0cbd3ec | bellard | { |
123 | f0cbd3ec | bellard | /*
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124 | f0cbd3ec | bellard | * If there's no room, realloc
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125 | f0cbd3ec | bellard | */
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126 | f0cbd3ec | bellard | if (M_FREEROOM(m) < n->m_len)
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127 | f0cbd3ec | bellard | m_inc(m,m->m_size+MINCSIZE); |
128 | 5fafdf24 | ths | |
129 | f0cbd3ec | bellard | memcpy(m->m_data+m->m_len, n->m_data, n->m_len); |
130 | f0cbd3ec | bellard | m->m_len += n->m_len; |
131 | f0cbd3ec | bellard | |
132 | f0cbd3ec | bellard | m_free(n); |
133 | f0cbd3ec | bellard | } |
134 | f0cbd3ec | bellard | |
135 | f0cbd3ec | bellard | |
136 | f0cbd3ec | bellard | /* make m size bytes large */
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137 | f0cbd3ec | bellard | void
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138 | f0cbd3ec | bellard | m_inc(m, size) |
139 | f0cbd3ec | bellard | struct mbuf *m;
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140 | f0cbd3ec | bellard | int size;
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141 | f0cbd3ec | bellard | { |
142 | 4b6ccfde | bellard | int datasize;
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143 | 4b6ccfde | bellard | |
144 | f0cbd3ec | bellard | /* some compiles throw up on gotos. This one we can fake. */
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145 | f0cbd3ec | bellard | if(m->m_size>size) return; |
146 | f0cbd3ec | bellard | |
147 | f0cbd3ec | bellard | if (m->m_flags & M_EXT) {
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148 | 4b6ccfde | bellard | datasize = m->m_data - m->m_ext; |
149 | f0cbd3ec | bellard | m->m_ext = (char *)realloc(m->m_ext,size);
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150 | f0cbd3ec | bellard | /* if (m->m_ext == NULL)
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151 | f0cbd3ec | bellard | * return (struct mbuf *)NULL;
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152 | 3b46e624 | ths | */
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153 | 4b6ccfde | bellard | m->m_data = m->m_ext + datasize; |
154 | f0cbd3ec | bellard | } else {
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155 | f0cbd3ec | bellard | char *dat;
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156 | f0cbd3ec | bellard | datasize = m->m_data - m->m_dat; |
157 | f0cbd3ec | bellard | dat = (char *)malloc(size);
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158 | f0cbd3ec | bellard | /* if (dat == NULL)
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159 | f0cbd3ec | bellard | * return (struct mbuf *)NULL;
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160 | f0cbd3ec | bellard | */
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161 | f0cbd3ec | bellard | memcpy(dat, m->m_dat, m->m_size); |
162 | 3b46e624 | ths | |
163 | f0cbd3ec | bellard | m->m_ext = dat; |
164 | f0cbd3ec | bellard | m->m_data = m->m_ext + datasize; |
165 | f0cbd3ec | bellard | m->m_flags |= M_EXT; |
166 | f0cbd3ec | bellard | } |
167 | 5fafdf24 | ths | |
168 | f0cbd3ec | bellard | m->m_size = size; |
169 | f0cbd3ec | bellard | |
170 | f0cbd3ec | bellard | } |
171 | f0cbd3ec | bellard | |
172 | f0cbd3ec | bellard | |
173 | f0cbd3ec | bellard | |
174 | f0cbd3ec | bellard | void
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175 | f0cbd3ec | bellard | m_adj(m, len) |
176 | f0cbd3ec | bellard | struct mbuf *m;
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177 | f0cbd3ec | bellard | int len;
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178 | f0cbd3ec | bellard | { |
179 | f0cbd3ec | bellard | if (m == NULL) |
180 | f0cbd3ec | bellard | return;
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181 | f0cbd3ec | bellard | if (len >= 0) { |
182 | f0cbd3ec | bellard | /* Trim from head */
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183 | f0cbd3ec | bellard | m->m_data += len; |
184 | f0cbd3ec | bellard | m->m_len -= len; |
185 | f0cbd3ec | bellard | } else {
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186 | f0cbd3ec | bellard | /* Trim from tail */
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187 | f0cbd3ec | bellard | len = -len; |
188 | f0cbd3ec | bellard | m->m_len -= len; |
189 | f0cbd3ec | bellard | } |
190 | f0cbd3ec | bellard | } |
191 | f0cbd3ec | bellard | |
192 | f0cbd3ec | bellard | |
193 | f0cbd3ec | bellard | /*
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194 | f0cbd3ec | bellard | * Copy len bytes from m, starting off bytes into n
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195 | f0cbd3ec | bellard | */
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196 | f0cbd3ec | bellard | int
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197 | f0cbd3ec | bellard | m_copy(n, m, off, len) |
198 | f0cbd3ec | bellard | struct mbuf *n, *m;
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199 | f0cbd3ec | bellard | int off, len;
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200 | f0cbd3ec | bellard | { |
201 | f0cbd3ec | bellard | if (len > M_FREEROOM(n))
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202 | f0cbd3ec | bellard | return -1; |
203 | f0cbd3ec | bellard | |
204 | f0cbd3ec | bellard | memcpy((n->m_data + n->m_len), (m->m_data + off), len); |
205 | f0cbd3ec | bellard | n->m_len += len; |
206 | f0cbd3ec | bellard | return 0; |
207 | f0cbd3ec | bellard | } |
208 | f0cbd3ec | bellard | |
209 | f0cbd3ec | bellard | |
210 | f0cbd3ec | bellard | /*
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211 | f0cbd3ec | bellard | * Given a pointer into an mbuf, return the mbuf
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212 | f0cbd3ec | bellard | * XXX This is a kludge, I should eliminate the need for it
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213 | f0cbd3ec | bellard | * Fortunately, it's not used often
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214 | f0cbd3ec | bellard | */
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215 | f0cbd3ec | bellard | struct mbuf *
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216 | f0cbd3ec | bellard | dtom(dat) |
217 | f0cbd3ec | bellard | void *dat;
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218 | f0cbd3ec | bellard | { |
219 | f0cbd3ec | bellard | struct mbuf *m;
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220 | 5fafdf24 | ths | |
221 | f0cbd3ec | bellard | DEBUG_CALL("dtom");
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222 | f0cbd3ec | bellard | DEBUG_ARG("dat = %lx", (long )dat); |
223 | f0cbd3ec | bellard | |
224 | f0cbd3ec | bellard | /* bug corrected for M_EXT buffers */
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225 | f0cbd3ec | bellard | for (m = m_usedlist.m_next; m != &m_usedlist; m = m->m_next) {
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226 | f0cbd3ec | bellard | if (m->m_flags & M_EXT) {
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227 | f0cbd3ec | bellard | if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) ) |
228 | f0cbd3ec | bellard | return m;
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229 | f0cbd3ec | bellard | } else {
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230 | f0cbd3ec | bellard | if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) ) |
231 | f0cbd3ec | bellard | return m;
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232 | f0cbd3ec | bellard | } |
233 | f0cbd3ec | bellard | } |
234 | 5fafdf24 | ths | |
235 | f0cbd3ec | bellard | DEBUG_ERROR((dfd, "dtom failed"));
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236 | 5fafdf24 | ths | |
237 | f0cbd3ec | bellard | return (struct mbuf *)0; |
238 | f0cbd3ec | bellard | } |