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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: */
1.1.1.7 root 26: #define SLIRP_MSIZE (IF_MTU + IF_MAXLINKHDR + offsetof(struct mbuf, m_dat) + 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 */
1.1.1.7 root 68: m->m_size = SLIRP_MSIZE - offsetof(struct mbuf, m_dat);
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;
1.1.1.8 ! root 73: m->arp_requested = false;
! 74: m->expiration_date = (uint64_t)-1;
1.1 root 75: end_error:
76: DEBUG_ARG("m = %lx", (long )m);
77: return m;
78: }
79:
80: void
1.1.1.5 root 81: m_free(struct mbuf *m)
1.1 root 82: {
1.1.1.3 root 83:
1.1 root 84: DEBUG_CALL("m_free");
85: DEBUG_ARG("m = %lx", (long )m);
1.1.1.3 root 86:
1.1 root 87: if(m) {
88: /* Remove from m_usedlist */
89: if (m->m_flags & M_USEDLIST)
90: remque(m);
1.1.1.3 root 91:
1.1 root 92: /* If it's M_EXT, free() it */
93: if (m->m_flags & M_EXT)
94: free(m->m_ext);
95:
96: /*
97: * Either free() it or put it on the free list
98: */
99: if (m->m_flags & M_DOFREE) {
1.1.1.5 root 100: m->slirp->mbuf_alloced--;
1.1.1.6 root 101: free(m);
1.1 root 102: } else if ((m->m_flags & M_FREELIST) == 0) {
1.1.1.5 root 103: insque(m,&m->slirp->m_freelist);
1.1 root 104: m->m_flags = M_FREELIST; /* Clobber other flags */
105: }
106: } /* if(m) */
107: }
108:
109: /*
110: * Copy data from one mbuf to the end of
111: * the other.. if result is too big for one mbuf, malloc()
112: * an M_EXT data segment
113: */
114: void
1.1.1.5 root 115: m_cat(struct mbuf *m, struct mbuf *n)
1.1 root 116: {
117: /*
118: * If there's no room, realloc
119: */
120: if (M_FREEROOM(m) < n->m_len)
121: m_inc(m,m->m_size+MINCSIZE);
1.1.1.3 root 122:
1.1 root 123: memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
124: m->m_len += n->m_len;
125:
126: m_free(n);
127: }
128:
129:
130: /* make m size bytes large */
131: void
1.1.1.5 root 132: m_inc(struct mbuf *m, int size)
1.1 root 133: {
1.1.1.2 root 134: int datasize;
135:
1.1 root 136: /* some compiles throw up on gotos. This one we can fake. */
137: if(m->m_size>size) return;
138:
139: if (m->m_flags & M_EXT) {
1.1.1.2 root 140: datasize = m->m_data - m->m_ext;
1.1 root 141: m->m_ext = (char *)realloc(m->m_ext,size);
1.1.1.2 root 142: m->m_data = m->m_ext + datasize;
1.1 root 143: } else {
144: char *dat;
145: datasize = m->m_data - m->m_dat;
146: dat = (char *)malloc(size);
147: memcpy(dat, m->m_dat, m->m_size);
1.1.1.3 root 148:
1.1 root 149: m->m_ext = dat;
150: m->m_data = m->m_ext + datasize;
151: m->m_flags |= M_EXT;
152: }
1.1.1.3 root 153:
1.1 root 154: m->m_size = size;
155:
156: }
157:
158:
159:
160: void
1.1.1.5 root 161: m_adj(struct mbuf *m, int len)
1.1 root 162: {
163: if (m == NULL)
164: return;
165: if (len >= 0) {
166: /* Trim from head */
167: m->m_data += len;
168: m->m_len -= len;
169: } else {
170: /* Trim from tail */
171: len = -len;
172: m->m_len -= len;
173: }
174: }
175:
176:
177: /*
178: * Copy len bytes from m, starting off bytes into n
179: */
180: int
1.1.1.5 root 181: m_copy(struct mbuf *n, struct mbuf *m, int off, int len)
1.1 root 182: {
183: if (len > M_FREEROOM(n))
184: return -1;
185:
186: memcpy((n->m_data + n->m_len), (m->m_data + off), len);
187: n->m_len += len;
188: return 0;
189: }
190:
191:
192: /*
193: * Given a pointer into an mbuf, return the mbuf
194: * XXX This is a kludge, I should eliminate the need for it
195: * Fortunately, it's not used often
196: */
197: struct mbuf *
1.1.1.5 root 198: dtom(Slirp *slirp, void *dat)
1.1 root 199: {
200: struct mbuf *m;
1.1.1.3 root 201:
1.1 root 202: DEBUG_CALL("dtom");
203: DEBUG_ARG("dat = %lx", (long )dat);
204:
205: /* bug corrected for M_EXT buffers */
1.1.1.5 root 206: for (m = slirp->m_usedlist.m_next; m != &slirp->m_usedlist;
207: m = m->m_next) {
1.1 root 208: if (m->m_flags & M_EXT) {
209: if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) )
210: return m;
211: } else {
212: if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) )
213: return m;
214: }
215: }
1.1.1.3 root 216:
1.1 root 217: DEBUG_ERROR((dfd, "dtom failed"));
1.1.1.3 root 218:
1.1 root 219: return (struct mbuf *)0;
220: }
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