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bellardf0cbd3e2004-04-22 00:10:48 +00001/*
2 * Copyright (c) 1995 Danny Gasparovski
3 *
4 * Please read the file COPYRIGHT for the
5 * terms and conditions of the copyright.
6 */
7
8/*
9 * mbuf's in SLiRP are much simpler than the real mbufs in
10 * FreeBSD. They are fixed size, determined by the MTU,
11 * so that one whole packet can fit. Mbuf's cannot be
12 * chained together. If there's more data than the mbuf
13 * could hold, an external malloced buffer is pointed to
14 * by m_ext (and the data pointers) and M_EXT is set in
15 * the flags
16 */
17
18#include <slirp.h>
19
blueswir19634d902007-10-26 19:01:16 +000020#define MBUF_THRESH 30
blueswir19634d902007-10-26 19:01:16 +000021
22/*
23 * Find a nice value for msize
24 * XXX if_maxlinkhdr already in mtu
25 */
Bruce Rogers53fae6d2011-02-05 14:47:56 -070026#define SLIRP_MSIZE (IF_MTU + IF_MAXLINKHDR + offsetof(struct mbuf, m_dat) + 6)
bellardf0cbd3e2004-04-22 00:10:48 +000027
28void
Jan Kiszka460fec62009-06-24 14:42:31 +020029m_init(Slirp *slirp)
bellardf0cbd3e2004-04-22 00:10:48 +000030{
Jan Kiszka460fec62009-06-24 14:42:31 +020031 slirp->m_freelist.m_next = slirp->m_freelist.m_prev = &slirp->m_freelist;
32 slirp->m_usedlist.m_next = slirp->m_usedlist.m_prev = &slirp->m_usedlist;
bellardf0cbd3e2004-04-22 00:10:48 +000033}
34
35/*
36 * Get an mbuf from the free list, if there are none
37 * malloc one
ths5fafdf22007-09-16 21:08:06 +000038 *
bellardf0cbd3e2004-04-22 00:10:48 +000039 * Because fragmentation can occur if we alloc new mbufs and
40 * free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
41 * which tells m_free to actually free() it
42 */
43struct mbuf *
Jan Kiszka460fec62009-06-24 14:42:31 +020044m_get(Slirp *slirp)
bellardf0cbd3e2004-04-22 00:10:48 +000045{
46 register struct mbuf *m;
47 int flags = 0;
ths5fafdf22007-09-16 21:08:06 +000048
bellardf0cbd3e2004-04-22 00:10:48 +000049 DEBUG_CALL("m_get");
ths5fafdf22007-09-16 21:08:06 +000050
Jan Kiszka460fec62009-06-24 14:42:31 +020051 if (slirp->m_freelist.m_next == &slirp->m_freelist) {
blueswir179383c92008-08-30 09:51:20 +000052 m = (struct mbuf *)malloc(SLIRP_MSIZE);
bellardf0cbd3e2004-04-22 00:10:48 +000053 if (m == NULL) goto end_error;
Jan Kiszka460fec62009-06-24 14:42:31 +020054 slirp->mbuf_alloced++;
55 if (slirp->mbuf_alloced > MBUF_THRESH)
bellardf0cbd3e2004-04-22 00:10:48 +000056 flags = M_DOFREE;
Jan Kiszka460fec62009-06-24 14:42:31 +020057 m->slirp = slirp;
bellardf0cbd3e2004-04-22 00:10:48 +000058 } else {
Jan Kiszka460fec62009-06-24 14:42:31 +020059 m = slirp->m_freelist.m_next;
bellardf0cbd3e2004-04-22 00:10:48 +000060 remque(m);
61 }
ths5fafdf22007-09-16 21:08:06 +000062
bellardf0cbd3e2004-04-22 00:10:48 +000063 /* Insert it in the used list */
Jan Kiszka460fec62009-06-24 14:42:31 +020064 insque(m,&slirp->m_usedlist);
bellardf0cbd3e2004-04-22 00:10:48 +000065 m->m_flags = (flags | M_USEDLIST);
ths5fafdf22007-09-16 21:08:06 +000066
bellardf0cbd3e2004-04-22 00:10:48 +000067 /* Initialise it */
Anthony Liguori8fe30462011-02-14 14:24:24 -060068 m->m_size = SLIRP_MSIZE - offsetof(struct mbuf, m_dat);
bellardf0cbd3e2004-04-22 00:10:48 +000069 m->m_data = m->m_dat;
70 m->m_len = 0;
blueswir1511d2b12009-03-07 15:32:56 +000071 m->m_nextpkt = NULL;
72 m->m_prevpkt = NULL;
bellardf0cbd3e2004-04-22 00:10:48 +000073end_error:
74 DEBUG_ARG("m = %lx", (long )m);
75 return m;
76}
77
78void
blueswir1511d2b12009-03-07 15:32:56 +000079m_free(struct mbuf *m)
bellardf0cbd3e2004-04-22 00:10:48 +000080{
ths5fafdf22007-09-16 21:08:06 +000081
bellardf0cbd3e2004-04-22 00:10:48 +000082 DEBUG_CALL("m_free");
83 DEBUG_ARG("m = %lx", (long )m);
ths5fafdf22007-09-16 21:08:06 +000084
bellardf0cbd3e2004-04-22 00:10:48 +000085 if(m) {
86 /* Remove from m_usedlist */
87 if (m->m_flags & M_USEDLIST)
88 remque(m);
ths5fafdf22007-09-16 21:08:06 +000089
bellardf0cbd3e2004-04-22 00:10:48 +000090 /* If it's M_EXT, free() it */
91 if (m->m_flags & M_EXT)
92 free(m->m_ext);
93
94 /*
95 * Either free() it or put it on the free list
96 */
97 if (m->m_flags & M_DOFREE) {
Jan Kiszka460fec62009-06-24 14:42:31 +020098 m->slirp->mbuf_alloced--;
Mark McLoughline0cf6d12009-11-20 18:13:10 +000099 free(m);
bellardf0cbd3e2004-04-22 00:10:48 +0000100 } else if ((m->m_flags & M_FREELIST) == 0) {
Jan Kiszka460fec62009-06-24 14:42:31 +0200101 insque(m,&m->slirp->m_freelist);
bellardf0cbd3e2004-04-22 00:10:48 +0000102 m->m_flags = M_FREELIST; /* Clobber other flags */
103 }
104 } /* if(m) */
105}
106
107/*
108 * Copy data from one mbuf to the end of
109 * the other.. if result is too big for one mbuf, malloc()
110 * an M_EXT data segment
111 */
112void
blueswir1511d2b12009-03-07 15:32:56 +0000113m_cat(struct mbuf *m, struct mbuf *n)
bellardf0cbd3e2004-04-22 00:10:48 +0000114{
115 /*
116 * If there's no room, realloc
117 */
118 if (M_FREEROOM(m) < n->m_len)
119 m_inc(m,m->m_size+MINCSIZE);
ths5fafdf22007-09-16 21:08:06 +0000120
bellardf0cbd3e2004-04-22 00:10:48 +0000121 memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
122 m->m_len += n->m_len;
123
124 m_free(n);
125}
126
127
128/* make m size bytes large */
129void
blueswir1511d2b12009-03-07 15:32:56 +0000130m_inc(struct mbuf *m, int size)
bellardf0cbd3e2004-04-22 00:10:48 +0000131{
bellard4b6ccfd2006-05-01 10:59:02 +0000132 int datasize;
133
bellardf0cbd3e2004-04-22 00:10:48 +0000134 /* some compiles throw up on gotos. This one we can fake. */
135 if(m->m_size>size) return;
136
137 if (m->m_flags & M_EXT) {
bellard4b6ccfd2006-05-01 10:59:02 +0000138 datasize = m->m_data - m->m_ext;
bellardf0cbd3e2004-04-22 00:10:48 +0000139 m->m_ext = (char *)realloc(m->m_ext,size);
bellard4b6ccfd2006-05-01 10:59:02 +0000140 m->m_data = m->m_ext + datasize;
bellardf0cbd3e2004-04-22 00:10:48 +0000141 } else {
bellardf0cbd3e2004-04-22 00:10:48 +0000142 char *dat;
143 datasize = m->m_data - m->m_dat;
144 dat = (char *)malloc(size);
bellardf0cbd3e2004-04-22 00:10:48 +0000145 memcpy(dat, m->m_dat, m->m_size);
ths3b46e622007-09-17 08:09:54 +0000146
bellardf0cbd3e2004-04-22 00:10:48 +0000147 m->m_ext = dat;
148 m->m_data = m->m_ext + datasize;
149 m->m_flags |= M_EXT;
150 }
ths5fafdf22007-09-16 21:08:06 +0000151
bellardf0cbd3e2004-04-22 00:10:48 +0000152 m->m_size = size;
153
154}
155
156
157
158void
blueswir1511d2b12009-03-07 15:32:56 +0000159m_adj(struct mbuf *m, int len)
bellardf0cbd3e2004-04-22 00:10:48 +0000160{
161 if (m == NULL)
162 return;
163 if (len >= 0) {
164 /* Trim from head */
165 m->m_data += len;
166 m->m_len -= len;
167 } else {
168 /* Trim from tail */
169 len = -len;
170 m->m_len -= len;
171 }
172}
173
174
175/*
176 * Copy len bytes from m, starting off bytes into n
177 */
178int
blueswir1511d2b12009-03-07 15:32:56 +0000179m_copy(struct mbuf *n, struct mbuf *m, int off, int len)
bellardf0cbd3e2004-04-22 00:10:48 +0000180{
181 if (len > M_FREEROOM(n))
182 return -1;
183
184 memcpy((n->m_data + n->m_len), (m->m_data + off), len);
185 n->m_len += len;
186 return 0;
187}
188
189
190/*
191 * Given a pointer into an mbuf, return the mbuf
192 * XXX This is a kludge, I should eliminate the need for it
193 * Fortunately, it's not used often
194 */
195struct mbuf *
Jan Kiszka460fec62009-06-24 14:42:31 +0200196dtom(Slirp *slirp, void *dat)
bellardf0cbd3e2004-04-22 00:10:48 +0000197{
198 struct mbuf *m;
ths5fafdf22007-09-16 21:08:06 +0000199
bellardf0cbd3e2004-04-22 00:10:48 +0000200 DEBUG_CALL("dtom");
201 DEBUG_ARG("dat = %lx", (long )dat);
202
203 /* bug corrected for M_EXT buffers */
Jan Kiszka460fec62009-06-24 14:42:31 +0200204 for (m = slirp->m_usedlist.m_next; m != &slirp->m_usedlist;
205 m = m->m_next) {
bellardf0cbd3e2004-04-22 00:10:48 +0000206 if (m->m_flags & M_EXT) {
207 if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) )
208 return m;
209 } else {
210 if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) )
211 return m;
212 }
213 }
ths5fafdf22007-09-16 21:08:06 +0000214
bellardf0cbd3e2004-04-22 00:10:48 +0000215 DEBUG_ERROR((dfd, "dtom failed"));
ths5fafdf22007-09-16 21:08:06 +0000216
bellardf0cbd3e2004-04-22 00:10:48 +0000217 return (struct mbuf *)0;
218}