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1.1 root 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: #include <slirp.h>
19:
1.1.1.3 root 20: #define MBUF_THRESH 30
21:
22: /*
23: * Find a nice value for msize
24: * XXX if_maxlinkhdr already in mtu
25: */
1.1.1.4 root 26: #define SLIRP_MSIZE (IF_MTU + IF_MAXLINKHDR + sizeof(struct m_hdr ) + 6)
1.1 root 27:
28: void
1.1.1.5 root 29: m_init(Slirp *slirp)
1.1 root 30: {
1.1.1.5 root 31: 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;
1.1 root 33: }
34:
35: /*
36: * Get an mbuf from the free list, if there are none
37: * malloc one
1.1.1.3 root 38: *
1.1 root 39: * 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: */
43: struct mbuf *
1.1.1.5 root 44: m_get(Slirp *slirp)
1.1 root 45: {
46: register struct mbuf *m;
47: int flags = 0;
1.1.1.3 root 48:
1.1 root 49: DEBUG_CALL("m_get");
1.1.1.3 root 50:
1.1.1.5 root 51: if (slirp->m_freelist.m_next == &slirp->m_freelist) {
1.1.1.4 root 52: m = (struct mbuf *)malloc(SLIRP_MSIZE);
1.1 root 53: if (m == NULL) goto end_error;
1.1.1.5 root 54: slirp->mbuf_alloced++;
55: if (slirp->mbuf_alloced > MBUF_THRESH)
1.1 root 56: flags = M_DOFREE;
1.1.1.5 root 57: m->slirp = slirp;
1.1 root 58: } else {
1.1.1.5 root 59: m = slirp->m_freelist.m_next;
1.1 root 60: remque(m);
61: }
1.1.1.3 root 62:
1.1 root 63: /* Insert it in the used list */
1.1.1.5 root 64: insque(m,&slirp->m_usedlist);
1.1 root 65: m->m_flags = (flags | M_USEDLIST);
1.1.1.3 root 66:
1.1 root 67: /* Initialise it */
1.1.1.4 root 68: m->m_size = SLIRP_MSIZE - sizeof(struct m_hdr);
1.1 root 69: m->m_data = m->m_dat;
70: m->m_len = 0;
1.1.1.5 root 71: m->m_nextpkt = NULL;
72: m->m_prevpkt = NULL;
1.1 root 73: end_error:
74: DEBUG_ARG("m = %lx", (long )m);
75: return m;
76: }
77:
78: void
1.1.1.5 root 79: m_free(struct mbuf *m)
1.1 root 80: {
1.1.1.3 root 81:
1.1 root 82: DEBUG_CALL("m_free");
83: DEBUG_ARG("m = %lx", (long )m);
1.1.1.3 root 84:
1.1 root 85: if(m) {
86: /* Remove from m_usedlist */
87: if (m->m_flags & M_USEDLIST)
88: remque(m);
1.1.1.3 root 89:
1.1 root 90: /* 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) {
1.1.1.5 root 98: m->slirp->mbuf_alloced--;
1.1.1.6 ! root 99: free(m);
1.1 root 100: } else if ((m->m_flags & M_FREELIST) == 0) {
1.1.1.5 root 101: insque(m,&m->slirp->m_freelist);
1.1 root 102: 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: */
112: void
1.1.1.5 root 113: m_cat(struct mbuf *m, struct mbuf *n)
1.1 root 114: {
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);
1.1.1.3 root 120:
1.1 root 121: 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 */
129: void
1.1.1.5 root 130: m_inc(struct mbuf *m, int size)
1.1 root 131: {
1.1.1.2 root 132: int datasize;
133:
1.1 root 134: /* 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) {
1.1.1.2 root 138: datasize = m->m_data - m->m_ext;
1.1 root 139: m->m_ext = (char *)realloc(m->m_ext,size);
1.1.1.2 root 140: m->m_data = m->m_ext + datasize;
1.1 root 141: } else {
142: char *dat;
143: datasize = m->m_data - m->m_dat;
144: dat = (char *)malloc(size);
145: memcpy(dat, m->m_dat, m->m_size);
1.1.1.3 root 146:
1.1 root 147: m->m_ext = dat;
148: m->m_data = m->m_ext + datasize;
149: m->m_flags |= M_EXT;
150: }
1.1.1.3 root 151:
1.1 root 152: m->m_size = size;
153:
154: }
155:
156:
157:
158: void
1.1.1.5 root 159: m_adj(struct mbuf *m, int len)
1.1 root 160: {
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: */
178: int
1.1.1.5 root 179: m_copy(struct mbuf *n, struct mbuf *m, int off, int len)
1.1 root 180: {
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: */
195: struct mbuf *
1.1.1.5 root 196: dtom(Slirp *slirp, void *dat)
1.1 root 197: {
198: struct mbuf *m;
1.1.1.3 root 199:
1.1 root 200: DEBUG_CALL("dtom");
201: DEBUG_ARG("dat = %lx", (long )dat);
202:
203: /* bug corrected for M_EXT buffers */
1.1.1.5 root 204: for (m = slirp->m_usedlist.m_next; m != &slirp->m_usedlist;
205: m = m->m_next) {
1.1 root 206: 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: }
1.1.1.3 root 214:
1.1 root 215: DEBUG_ERROR((dfd, "dtom failed"));
1.1.1.3 root 216:
1.1 root 217: return (struct mbuf *)0;
218: }
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