--- /dev/null
+/*
+ * 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 <slirp.h>
+
+#define MBUF_THRESH 30
+
+/*
+ * Find a nice value for msize
+ * XXX if_maxlinkhdr already in mtu
+ */
+#define SLIRP_MSIZE (IF_MTU + IF_MAXLINKHDR + offsetof(struct mbuf, m_dat) + 6)
+
+void
+m_init(Slirp *slirp)
+{
+ slirp->m_freelist.m_next = slirp->m_freelist.m_prev = &slirp->m_freelist;
+ slirp->m_usedlist.m_next = slirp->m_usedlist.m_prev = &slirp->m_usedlist;
+}
+
+void m_cleanup(Slirp *slirp)
+{
+ struct mbuf *m, *next;
+
+ m = slirp->m_usedlist.m_next;
+ while (m != &slirp->m_usedlist) {
+ next = m->m_next;
+ if (m->m_flags & M_EXT) {
+ free(m->m_ext);
+ }
+ free(m);
+ m = next;
+ }
+ m = slirp->m_freelist.m_next;
+ while (m != &slirp->m_freelist) {
+ next = m->m_next;
+ free(m);
+ m = next;
+ }
+}
+
+/*
+ * 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(Slirp *slirp)
+{
+ register struct mbuf *m;
+ int flags = 0;
+
+ DEBUG_CALL("m_get");
+
+ if (slirp->m_freelist.m_next == &slirp->m_freelist) {
+ m = (struct mbuf *)malloc(SLIRP_MSIZE);
+ if (m == NULL) goto end_error;
+ slirp->mbuf_alloced++;
+ if (slirp->mbuf_alloced > MBUF_THRESH)
+ flags = M_DOFREE;
+ m->slirp = slirp;
+ } else {
+ m = slirp->m_freelist.m_next;
+ remque(m);
+ }
+
+ /* Insert it in the used list */
+ insque(m,&slirp->m_usedlist);
+ m->m_flags = (flags | M_USEDLIST);
+
+ /* Initialise it */
+ m->m_size = SLIRP_MSIZE - offsetof(struct mbuf, m_dat);
+ m->m_data = m->m_dat;
+ m->m_len = 0;
+ m->m_nextpkt = NULL;
+ m->m_prevpkt = NULL;
+ m->arp_requested = false;
+ m->expiration_date = (uint64_t)-1;
+end_error:
+ DEBUG_ARG("m = %lx", (long )m);
+ return m;
+}
+
+void
+m_free(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) {
+ m->slirp->mbuf_alloced--;
+ free(m);
+ } else if ((m->m_flags & M_FREELIST) == 0) {
+ insque(m,&m->slirp->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(struct mbuf *m, struct mbuf *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(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);
+ m->m_data = m->m_ext + datasize;
+ } else {
+ char *dat;
+ datasize = m->m_data - m->m_dat;
+ dat = (char *)malloc(size);
+ 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(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(struct mbuf *n, struct mbuf *m, int off, int 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(Slirp *slirp, void *dat)
+{
+ struct mbuf *m;
+
+ DEBUG_CALL("dtom");
+ DEBUG_ARG("dat = %lx", (long )dat);
+
+ /* bug corrected for M_EXT buffers */
+ for (m = slirp->m_usedlist.m_next; m != &slirp->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;
+}
Code Review / kvmfornfv.git / blobdiff