src/slirp/mbuf.c

/*
 * 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 malloced buffer is pointed to
 * by m_ext (and the data pointers) and M_EXT is set in
 * the flags
 */

#include <stdlib.h>
#include <slirp.h>

struct  mbuf *mbutl;
char    *mclrefcnt;
int mbuf_alloced = 0;
struct mbuf m_freelist, m_usedlist;
int mbuf_thresh = 30;
int mbuf_max = 0;
int msize;

void
m_init()
{
        m_freelist.m_next = m_freelist.m_prev = &m_freelist;
        m_usedlist.m_next = m_usedlist.m_prev = &m_usedlist;
        msize_init();
}

void
msize_init()
{
        /*
         * Find a nice value for msize
         * XXX if_maxlinkhdr already in mtu
         */
        msize = (if_mtu>if_mru?if_mtu:if_mru) + 
                        if_maxlinkhdr + sizeof(struct m_hdr ) + 6;
}

/*
 * Get an mbuf from the free list, if there are none
 * malloc 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 free() it
 */
struct mbuf *
m_get()
{
        register struct mbuf *m;
        int flags = 0;
        
        DEBUG_CALL("m_get");
        
        if (m_freelist.m_next == &m_freelist) {
                m = (struct mbuf *)malloc(msize);
                if (m == NULL) goto end_error;
                mbuf_alloced++;
                if (mbuf_alloced > mbuf_thresh)
                        flags = M_DOFREE;
                if (mbuf_alloced > mbuf_max)
                        mbuf_max = mbuf_alloced;
        } else {
                m = m_freelist.m_next;
                remque(m);
        }
        
        /* Insert it in the used list */
        insque(m,&m_usedlist);
        m->m_flags = (flags | M_USEDLIST);
        
        /* Initialise it */
        m->m_size = msize - sizeof(struct m_hdr);
        m->m_data = m->m_dat;
        m->m_len = 0;
        m->m_nextpkt = 0;
        m->m_prevpkt = 0;
end_error:
        DEBUG_ARG("m = %lx", (long )m);
        return m;
}

void
m_free(m)
        struct mbuf *m;
{
        
  DEBUG_CALL("m_free");
  DEBUG_ARG("m = %lx", (long )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)
           free(m->m_ext);

        /*
         * Either free() it or put it on the free list
         */
        if (m->m_flags & M_DOFREE) {
                free(m);
                mbuf_alloced--;
        } else if ((m->m_flags & M_FREELIST) == 0) {
                insque(m,&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, malloc()
 * an M_EXT data segment
 */
void
m_cat(m, n)
        register struct mbuf *m, *n;
{
        /*
         * If there's no room, realloc
         */
        if (M_FREEROOM(m) < n->m_len)
                m_inc(m,m->m_size+MINCSIZE);
        
        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 */
void
m_inc(m, size)
        struct mbuf *m;
        int size;
{
       int datasize;

        /* some compiles throw up on gotos.  This one we can fake. */
        if(m->m_size>size) return;

        if (m->m_flags & M_EXT) {
         datasize = m->m_data - m->m_ext;
          m->m_ext = (char *)realloc(m->m_ext,size);
/*              if (m->m_ext == NULL)
 *                      return (struct mbuf *)NULL;
 */             
         m->m_data = m->m_ext + datasize;
        } else {
          char *dat;
          datasize = m->m_data - m->m_dat;
          dat = (char *)malloc(size);
/*              if (dat == NULL)
 *                      return (struct mbuf *)NULL;
 */
          memcpy(dat, m->m_dat, m->m_size);
          
          m->m_ext = dat;
          m->m_data = m->m_ext + datasize;
          m->m_flags |= M_EXT;
        }
 
        m->m_size = size;

}


void
m_adj(m, len)
        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(n, m, off, len)
        struct mbuf *n, *m;
        int off, 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(dat)
        void *dat;
{
        struct mbuf *m;
        
        DEBUG_CALL("dtom");
        DEBUG_ARG("dat = %lx", (long )dat);

        /* bug corrected for M_EXT buffers */
        for (m = m_usedlist.m_next; m != &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((dfd, "dtom failed"));
        
        return (struct mbuf *)0;
}

Revision:	1.3
Committed:	2007-01-22T14:48:40Z (17 years, 9 months ago) by asvitkine
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.2:	+1 -0 lines
Log Message:	fix compile warnings w/ slirp caused by not including stdlib
#	User	Rev	Content
1	gbeauche	1.1	/*
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	asvitkine	1.3	#include <stdlib.h>
19	gbeauche	1.1	#include <slirp.h>
20
21			struct mbuf *mbutl;
22			char *mclrefcnt;
23			int mbuf_alloced = 0;
24			struct mbuf m_freelist, m_usedlist;
25			int mbuf_thresh = 30;
26			int mbuf_max = 0;
27			int msize;
28
29			void
30			m_init()
31			{
32			m_freelist.m_next = m_freelist.m_prev = &m_freelist;
33			m_usedlist.m_next = m_usedlist.m_prev = &m_usedlist;
34			msize_init();
35			}
36
37			void
38			msize_init()
39			{
40			/*
41			* Find a nice value for msize
42			* XXX if_maxlinkhdr already in mtu
43			*/
44			msize = (if_mtu>if_mru?if_mtu:if_mru) +
45			if_maxlinkhdr + sizeof(struct m_hdr ) + 6;
46			}
47
48			/*
49			* Get an mbuf from the free list, if there are none
50			* malloc one
51			*
52			* Because fragmentation can occur if we alloc new mbufs and
53			* free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
54			* which tells m_free to actually free() it
55			*/
56			struct mbuf *
57			m_get()
58			{
59			register struct mbuf *m;
60			int flags = 0;
61
62			DEBUG_CALL("m_get");
63
64			if (m_freelist.m_next == &m_freelist) {
65			m = (struct mbuf *)malloc(msize);
66			if (m == NULL) goto end_error;
67			mbuf_alloced++;
68			if (mbuf_alloced > mbuf_thresh)
69			flags = M_DOFREE;
70			if (mbuf_alloced > mbuf_max)
71			mbuf_max = mbuf_alloced;
72			} else {
73			m = m_freelist.m_next;
74			remque(m);
75			}
76
77			/* Insert it in the used list */
78			insque(m,&m_usedlist);
79			m->m_flags = (flags \| M_USEDLIST);
80
81			/* Initialise it */
82			m->m_size = msize - sizeof(struct m_hdr);
83			m->m_data = m->m_dat;
84			m->m_len = 0;
85			m->m_nextpkt = 0;
86			m->m_prevpkt = 0;
87			end_error:
88			DEBUG_ARG("m = %lx", (long )m);
89			return m;
90			}
91
92			void
93			m_free(m)
94			struct mbuf *m;
95			{
96
97			DEBUG_CALL("m_free");
98			DEBUG_ARG("m = %lx", (long )m);
99
100			if(m) {
101			/* Remove from m_usedlist */
102			if (m->m_flags & M_USEDLIST)
103			remque(m);
104
105			/* If it's M_EXT, free() it */
106			if (m->m_flags & M_EXT)
107			free(m->m_ext);
108
109			/*
110			* Either free() it or put it on the free list
111			*/
112			if (m->m_flags & M_DOFREE) {
113			free(m);
114			mbuf_alloced--;
115			} else if ((m->m_flags & M_FREELIST) == 0) {
116			insque(m,&m_freelist);
117			m->m_flags = M_FREELIST; /* Clobber other flags */
118			}
119			} /* if(m) */
120			}
121
122			/*
123			* Copy data from one mbuf to the end of
124			* the other.. if result is too big for one mbuf, malloc()
125			* an M_EXT data segment
126			*/
127			void
128			m_cat(m, n)
129			register struct mbuf m, n;
130			{
131			/*
132			* If there's no room, realloc
133			*/
134			if (M_FREEROOM(m) < n->m_len)
135			m_inc(m,m->m_size+MINCSIZE);
136
137			memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
138			m->m_len += n->m_len;
139
140			m_free(n);
141			}
142
143
144			/* make m size bytes large */
145			void
146			m_inc(m, size)
147			struct mbuf *m;
148			int size;
149			{
150	gbeauche	1.2	int datasize;
151
152	gbeauche	1.1	/* some compiles throw up on gotos. This one we can fake. */
153			if(m->m_size>size) return;
154
155			if (m->m_flags & M_EXT) {
156	gbeauche	1.2	datasize = m->m_data - m->m_ext;
157	gbeauche	1.1	m->m_ext = (char *)realloc(m->m_ext,size);
158			/* if (m->m_ext == NULL)
159			* return (struct mbuf *)NULL;
160			*/
161	gbeauche	1.2	m->m_data = m->m_ext + datasize;
162	gbeauche	1.1	} else {
163			char *dat;
164			datasize = m->m_data - m->m_dat;
165			dat = (char *)malloc(size);
166			/* if (dat == NULL)
167			* return (struct mbuf *)NULL;
168			*/
169			memcpy(dat, m->m_dat, m->m_size);
170
171			m->m_ext = dat;
172			m->m_data = m->m_ext + datasize;
173			m->m_flags \|= M_EXT;
174			}
175
176			m->m_size = size;
177
178			}
179
180
181
182			void
183			m_adj(m, len)
184			struct mbuf *m;
185			int len;
186			{
187			if (m == NULL)
188			return;
189			if (len >= 0) {
190			/* Trim from head */
191			m->m_data += len;
192			m->m_len -= len;
193			} else {
194			/* Trim from tail */
195			len = -len;
196			m->m_len -= len;
197			}
198			}
199
200
201			/*
202			* Copy len bytes from m, starting off bytes into n
203			*/
204			int
205			m_copy(n, m, off, len)
206			struct mbuf n, m;
207			int off, len;
208			{
209			if (len > M_FREEROOM(n))
210			return -1;
211
212			memcpy((n->m_data + n->m_len), (m->m_data + off), len);
213			n->m_len += len;
214			return 0;
215			}
216
217
218			/*
219			* Given a pointer into an mbuf, return the mbuf
220			* XXX This is a kludge, I should eliminate the need for it
221			* Fortunately, it's not used often
222			*/
223			struct mbuf *
224			dtom(dat)
225			void *dat;
226			{
227			struct mbuf *m;
228
229			DEBUG_CALL("dtom");
230			DEBUG_ARG("dat = %lx", (long )dat);
231
232			/* bug corrected for M_EXT buffers */
233			for (m = m_usedlist.m_next; m != &m_usedlist; m = m->m_next) {
234			if (m->m_flags & M_EXT) {
235			if( (char )dat>=m->m_ext && (char )dat<(m->m_ext + m->m_size) )
236			return m;
237			} else {
238			if( (char )dat >= m->m_dat && (char )dat<(m->m_dat + m->m_size) )
239			return m;
240			}
241			}
242
243			DEBUG_ERROR((dfd, "dtom failed"));
244
245			return (struct mbuf *)0;
246			}
247