diff options
Diffstat (limited to 'slirp/src/mbuf.c')
| -rw-r--r-- | slirp/src/mbuf.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/slirp/src/mbuf.c b/slirp/src/mbuf.c new file mode 100644 index 0000000000..521c02c967 --- /dev/null +++ b/slirp/src/mbuf.c @@ -0,0 +1,237 @@ +/* + * 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 g_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 + */ +#define SLIRP_MSIZE\ + (offsetof(struct mbuf, m_dat) + IF_MAXLINKHDR + TCPIPHDR_DELTA + IF_MTU) + +void +m_init(Slirp *slirp) +{ + slirp->m_freelist.qh_link = slirp->m_freelist.qh_rlink = &slirp->m_freelist; + slirp->m_usedlist.qh_link = slirp->m_usedlist.qh_rlink = &slirp->m_usedlist; +} + +void m_cleanup(Slirp *slirp) +{ + struct mbuf *m, *next; + + m = (struct mbuf *) slirp->m_usedlist.qh_link; + while ((struct quehead *) m != &slirp->m_usedlist) { + next = m->m_next; + if (m->m_flags & M_EXT) { + g_free(m->m_ext); + } + g_free(m); + m = next; + } + m = (struct mbuf *) slirp->m_freelist.qh_link; + while ((struct quehead *) m != &slirp->m_freelist) { + next = m->m_next; + g_free(m); + m = next; + } +} + +/* + * Get an mbuf from the free list, if there are none + * allocate 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 g_free() it + */ +struct mbuf * +m_get(Slirp *slirp) +{ + register struct mbuf *m; + int flags = 0; + + DEBUG_CALL("m_get"); + + if (slirp->m_freelist.qh_link == &slirp->m_freelist) { + m = g_malloc(SLIRP_MSIZE); + slirp->mbuf_alloced++; + if (slirp->mbuf_alloced > MBUF_THRESH) + flags = M_DOFREE; + m->slirp = slirp; + } else { + m = (struct mbuf *) slirp->m_freelist.qh_link; + 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->resolution_requested = false; + m->expiration_date = (uint64_t)-1; + DEBUG_ARG("m = %p", m); + return m; +} + +void +m_free(struct mbuf *m) +{ + + DEBUG_CALL("m_free"); + DEBUG_ARG("m = %p", 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) { + g_free(m->m_ext); + } + /* + * Either free() it or put it on the free list + */ + if (m->m_flags & M_DOFREE) { + m->slirp->mbuf_alloced--; + g_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, allocate + * 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_len + n->m_len); + + 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 from m_data */ +void +m_inc(struct mbuf *m, int size) +{ + int gapsize; + + /* some compilers throw up on gotos. This one we can fake. */ + if (M_ROOM(m) > size) { + return; + } + + if (m->m_flags & M_EXT) { + gapsize = m->m_data - m->m_ext; + m->m_ext = g_realloc(m->m_ext, size + gapsize); + } else { + gapsize = m->m_data - m->m_dat; + m->m_ext = g_malloc(size + gapsize); + memcpy(m->m_ext, m->m_dat, m->m_size); + m->m_flags |= M_EXT; + } + + m->m_data = m->m_ext + gapsize; + m->m_size = size + gapsize; +} + + + +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 = %p", dat); + + /* bug corrected for M_EXT buffers */ + for (m = (struct mbuf *) slirp->m_usedlist.qh_link; + (struct quehead *) 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("dtom failed"); + + return (struct mbuf *)0; +} |