/* * Copyright (c) 1982, 1986, 1988, 1991, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94 * $FreeBSD$ */ #include "opt_param.h" #include #include #include #include #include #include #include #include #include #include #include #ifdef INVARIANTS #include #endif static void mbinit __P((void *)); SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) struct mbuf *mbutl; struct mbstat mbstat; u_long mbtypes[MT_NTYPES]; struct mbuf *mmbfree; union mcluster *mclfree; union mext_refcnt *mext_refcnt_free; int max_linkhdr; int max_protohdr; int max_hdr; int max_datalen; int nmbclusters; int nmbufs; u_int m_mballoc_wid = 0; u_int m_clalloc_wid = 0; SYSCTL_DECL(_kern_ipc); SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW, &max_linkhdr, 0, ""); SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW, &max_protohdr, 0, ""); SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, ""); SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW, &max_datalen, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW, &mbuf_wait, 0, ""); SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RD, &mbstat, mbstat, ""); SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes, sizeof(mbtypes), "LU", ""); SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD, &nmbclusters, 0, "Maximum number of mbuf clusters available"); SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RD, &nmbufs, 0, "Maximum number of mbufs available"); #ifndef NMBCLUSTERS #define NMBCLUSTERS (512 + MAXUSERS * 16) #endif TUNABLE_INT_DECL("kern.ipc.nmbclusters", NMBCLUSTERS, nmbclusters); TUNABLE_INT_DECL("kern.ipc.nmbufs", NMBCLUSTERS * 4, nmbufs); static void m_reclaim __P((void)); #define NCL_INIT 2 #define NMB_INIT 16 #define REF_INIT (NMBCLUSTERS * 2) /* ARGSUSED*/ static void mbinit(dummy) void *dummy; { int s; mmbfree = NULL; mclfree = NULL; mext_refcnt_free = NULL; mbstat.m_msize = MSIZE; mbstat.m_mclbytes = MCLBYTES; mbstat.m_minclsize = MINCLSIZE; mbstat.m_mlen = MLEN; mbstat.m_mhlen = MHLEN; s = splimp(); if (m_alloc_ref(REF_INIT) == 0) goto bad; if (m_mballoc(NMB_INIT, M_DONTWAIT) == 0) goto bad; #if MCLBYTES <= PAGE_SIZE if (m_clalloc(NCL_INIT, M_DONTWAIT) == 0) goto bad; #else /* It's OK to call contigmalloc in this context. */ if (m_clalloc(16, M_WAIT) == 0) goto bad; #endif splx(s); return; bad: panic("mbinit: failed to initialize mbuf subsystem!"); } /* * Allocate at least nmb reference count structs and place them * on the ref cnt free list. * Must be called at splimp. */ int m_alloc_ref(nmb) u_int nmb; { caddr_t p; u_int nbytes; int i; /* * XXX: * We don't cap the amount of memory that can be used * by the reference counters, like we do for mbufs and * mbuf clusters. The reason is that we don't really expect * to have to be allocating too many of these guys with m_alloc_ref(), * and if we are, we're probably not out of the woods anyway, * so leave this way for now. */ if (mb_map_full) return (0); nbytes = round_page(nmb * sizeof(union mext_refcnt)); if ((p = (caddr_t)kmem_malloc(mb_map, nbytes, M_NOWAIT)) == NULL) return (0); nmb = nbytes / sizeof(union mext_refcnt); for (i = 0; i < nmb; i++) { ((union mext_refcnt *)p)->next_ref = mext_refcnt_free; mext_refcnt_free = (union mext_refcnt *)p; p += sizeof(union mext_refcnt); mbstat.m_refree++; } mbstat.m_refcnt += nmb; return (1); } /* * Allocate at least nmb mbufs and place on mbuf free list. * Must be called at splimp. */ /* ARGSUSED */ int m_mballoc(nmb, how) register int nmb; int how; { register caddr_t p; register int i; int nbytes; /* * If we've hit the mbuf limit, stop allocating from mb_map, * (or trying to) in order to avoid dipping into the section of * mb_map which we've "reserved" for clusters. */ if ((nmb + mbstat.m_mbufs) > nmbufs) return (0); /* * Once we run out of map space, it will be impossible to get * any more (nothing is ever freed back to the map) * -- however you are not dead as m_reclaim might * still be able to free a substantial amount of space. * * XXX Furthermore, we can also work with "recycled" mbufs (when * we're calling with M_WAIT the sleep procedure will be woken * up when an mbuf is freed. See m_mballoc_wait()). */ if (mb_map_full) return (0); nbytes = round_page(nmb * MSIZE); p = (caddr_t)kmem_malloc(mb_map, nbytes, M_NOWAIT); if (p == 0 && how == M_WAIT) { mbstat.m_wait++; p = (caddr_t)kmem_malloc(mb_map, nbytes, M_WAITOK); } /* * Either the map is now full, or `how' is M_NOWAIT and there * are no pages left. */ if (p == NULL) return (0); nmb = nbytes / MSIZE; for (i = 0; i < nmb; i++) { ((struct mbuf *)p)->m_next = mmbfree; mmbfree = (struct mbuf *)p; p += MSIZE; } mbstat.m_mbufs += nmb; mbtypes[MT_FREE] += nmb; return (1); } /* * Once the mb_map has been exhausted and if the call to the allocation macros * (or, in some cases, functions) is with M_WAIT, then it is necessary to rely * solely on reclaimed mbufs. Here we wait for an mbuf to be freed for a * designated (mbuf_wait) time. */ struct mbuf * m_mballoc_wait(int caller, int type) { struct mbuf *p; int s; m_mballoc_wid++; if ((tsleep(&m_mballoc_wid, PVM, "mballc", mbuf_wait)) == EWOULDBLOCK) m_mballoc_wid--; /* * Now that we (think) that we've got something, we will redo an * MGET, but avoid getting into another instance of m_mballoc_wait() * XXX: We retry to fetch _even_ if the sleep timed out. This is left * this way, purposely, in the [unlikely] case that an mbuf was * freed but the sleep was not awakened in time. */ p = NULL; switch (caller) { case MGET_C: MGET(p, M_DONTWAIT, type); break; case MGETHDR_C: MGETHDR(p, M_DONTWAIT, type); break; default: panic("m_mballoc_wait: invalid caller (%d)", caller); } s = splimp(); if (p != NULL) { /* We waited and got something... */ mbstat.m_wait++; /* Wake up another if we have more free. */ if (mmbfree != NULL) MMBWAKEUP(); } splx(s); return (p); } #if MCLBYTES > PAGE_SIZE static int i_want_my_mcl; static void kproc_mclalloc(void) { int status; while (1) { tsleep(&i_want_my_mcl, PVM, "mclalloc", 0); for (; i_want_my_mcl; i_want_my_mcl--) { if (m_clalloc(1, M_WAIT) == 0) printf("m_clalloc failed even in process context!\n"); } } } static struct proc *mclallocproc; static struct kproc_desc mclalloc_kp = { "mclalloc", kproc_mclalloc, &mclallocproc }; SYSINIT(mclallocproc, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY, kproc_start, &mclalloc_kp); #endif /* * Allocate some number of mbuf clusters * and place on cluster free list. * Must be called at splimp. */ /* ARGSUSED */ int m_clalloc(ncl, how) register int ncl; int how; { register caddr_t p; register int i; int npg; /* * If we've hit the mcluster number limit, stop allocating from * mb_map, (or trying to) in order to avoid dipping into the section * of mb_map which we've "reserved" for mbufs. */ if ((ncl + mbstat.m_clusters) > nmbclusters) { mbstat.m_drops++; return (0); } /* * Once we run out of map space, it will be impossible * to get any more (nothing is ever freed back to the * map). From this point on, we solely rely on freed * mclusters. */ if (mb_map_full) { mbstat.m_drops++; return (0); } #if MCLBYTES > PAGE_SIZE if (how != M_WAIT) { i_want_my_mcl += ncl; wakeup(&i_want_my_mcl); mbstat.m_wait++; p = 0; } else { p = contigmalloc1(MCLBYTES * ncl, M_DEVBUF, M_WAITOK, 0ul, ~0ul, PAGE_SIZE, 0, mb_map); } #else npg = ncl; p = (caddr_t)kmem_malloc(mb_map, ctob(npg), how != M_WAIT ? M_NOWAIT : M_WAITOK); ncl = ncl * PAGE_SIZE / MCLBYTES; #endif /* * Either the map is now full, or `how' is M_NOWAIT and there * are no pages left. */ if (p == NULL) { mbstat.m_drops++; return (0); } for (i = 0; i < ncl; i++) { ((union mcluster *)p)->mcl_next = mclfree; mclfree = (union mcluster *)p; p += MCLBYTES; mbstat.m_clfree++; } mbstat.m_clusters += ncl; return (1); } /* * Once the mb_map submap has been exhausted and the allocation is called with * M_WAIT, we rely on the mclfree union pointers. If nothing is free, we will * sleep for a designated amount of time (mbuf_wait) or until we're woken up * due to sudden mcluster availability. */ caddr_t m_clalloc_wait(void) { caddr_t p; int s; #ifdef __i386__ /* If in interrupt context, and INVARIANTS, maintain sanity and die. */ KASSERT(intr_nesting_level == 0, ("CLALLOC: CANNOT WAIT IN INTERRUPT")); #endif /* Sleep until something's available or until we expire. */ m_clalloc_wid++; if ((tsleep(&m_clalloc_wid, PVM, "mclalc", mbuf_wait)) == EWOULDBLOCK) m_clalloc_wid--; /* * Now that we (think) that we've got something, we will redo and * MGET, but avoid getting into another instance of m_clalloc_wait() */ p = NULL; _MCLALLOC(p, M_DONTWAIT); s = splimp(); if (p != NULL) { /* We waited and got something... */ mbstat.m_wait++; /* Wake up another if we have more free. */ if (mclfree != NULL) MCLWAKEUP(); } splx(s); return (p); } /* * When MGET fails, ask protocols to free space when short of memory, * then re-attempt to allocate an mbuf. */ struct mbuf * m_retry(i, t) int i, t; { register struct mbuf *m; /* * Must only do the reclaim if not in an interrupt context. */ if (i == M_WAIT) { #ifdef __i386__ KASSERT(intr_nesting_level == 0, ("MBALLOC: CANNOT WAIT IN INTERRUPT")); #endif m_reclaim(); } /* * Both m_mballoc_wait and m_retry must be nulled because * when the MGET macro is run from here, we deffinately do _not_ * want to enter an instance of m_mballoc_wait() or m_retry() (again!) */ #define m_mballoc_wait(caller,type) (struct mbuf *)0 #define m_retry(i, t) (struct mbuf *)0 MGET(m, i, t); #undef m_retry #undef m_mballoc_wait if (m != NULL) mbstat.m_wait++; else mbstat.m_drops++; return (m); } /* * As above; retry an MGETHDR. */ struct mbuf * m_retryhdr(i, t) int i, t; { register struct mbuf *m; /* * Must only do the reclaim if not in an interrupt context. */ if (i == M_WAIT) { #ifdef __i386__ KASSERT(intr_nesting_level == 0, ("MBALLOC: CANNOT WAIT IN INTERRUPT")); #endif m_reclaim(); } #define m_mballoc_wait(caller,type) (struct mbuf *)0 #define m_retryhdr(i, t) (struct mbuf *)0 MGETHDR(m, i, t); #undef m_retryhdr #undef m_mballoc_wait if (m != NULL) mbstat.m_wait++; else mbstat.m_drops++; return (m); } static void m_reclaim() { register struct domain *dp; register struct protosw *pr; int s = splimp(); for (dp = domains; dp; dp = dp->dom_next) for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) if (pr->pr_drain) (*pr->pr_drain)(); splx(s); mbstat.m_drain++; } /* * Space allocation routines. * These are also available as macros * for critical paths. */ struct mbuf * m_get(how, type) int how, type; { register struct mbuf *m; MGET(m, how, type); return (m); } struct mbuf * m_gethdr(how, type) int how, type; { register struct mbuf *m; MGETHDR(m, how, type); return (m); } struct mbuf * m_getclr(how, type) int how, type; { register struct mbuf *m; MGET(m, how, type); if (m == 0) return (0); bzero(mtod(m, caddr_t), MLEN); return (m); } struct mbuf * m_free(m) struct mbuf *m; { register struct mbuf *n; MFREE(m, n); return (n); } void m_freem(m) register struct mbuf *m; { register struct mbuf *n; if (m == NULL) return; do { /* * we do need to check non-first mbuf, since some of existing * code does not call M_PREPEND properly. * (example: call to bpf_mtap from drivers) */ if ((m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.aux) { m_freem(m->m_pkthdr.aux); m->m_pkthdr.aux = NULL; } MFREE(m, n); m = n; } while (m); } /* * Mbuffer utility routines. */ /* * Lesser-used path for M_PREPEND: * allocate new mbuf to prepend to chain, * copy junk along. */ struct mbuf * m_prepend(m, len, how) register struct mbuf *m; int len, how; { struct mbuf *mn; MGET(mn, how, m->m_type); if (mn == (struct mbuf *)NULL) { m_freem(m); return ((struct mbuf *)NULL); } if (m->m_flags & M_PKTHDR) { M_COPY_PKTHDR(mn, m); m->m_flags &= ~M_PKTHDR; } mn->m_next = m; m = mn; if (len < MHLEN) MH_ALIGN(m, len); m->m_len = len; return (m); } /* * Make a copy of an mbuf chain starting "off0" bytes from the beginning, * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller. * Note that the copy is read-only, because clusters are not copied, * only their reference counts are incremented. */ #define MCFail (mbstat.m_mcfail) struct mbuf * m_copym(m, off0, len, wait) register struct mbuf *m; int off0, wait; register int len; { register struct mbuf *n, **np; register int off = off0; struct mbuf *top; int copyhdr = 0; KASSERT(off >= 0, ("m_copym, negative off %d", off)); KASSERT(len >= 0, ("m_copym, negative len %d", len)); if (off == 0 && m->m_flags & M_PKTHDR) copyhdr = 1; while (off > 0) { KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } np = ⊤ top = 0; while (len > 0) { if (m == 0) { KASSERT(len == M_COPYALL, ("m_copym, length > size of mbuf chain")); break; } MGET(n, wait, m->m_type); *np = n; if (n == 0) goto nospace; if (copyhdr) { M_COPY_PKTHDR(n, m); if (len == M_COPYALL) n->m_pkthdr.len -= off0; else n->m_pkthdr.len = len; copyhdr = 0; } n->m_len = min(len, m->m_len - off); if (m->m_flags & M_EXT) { n->m_data = m->m_data + off; n->m_ext = m->m_ext; n->m_flags |= M_EXT; MEXT_ADD_REF(m); } else bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), (unsigned)n->m_len); if (len != M_COPYALL) len -= n->m_len; off = 0; m = m->m_next; np = &n->m_next; } if (top == 0) MCFail++; return (top); nospace: m_freem(top); MCFail++; return (0); } /* * Copy an entire packet, including header (which must be present). * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. * Note that the copy is read-only, because clusters are not copied, * only their reference counts are incremented. */ struct mbuf * m_copypacket(m, how) struct mbuf *m; int how; { struct mbuf *top, *n, *o; MGET(n, how, m->m_type); top = n; if (!n) goto nospace; M_COPY_PKTHDR(n, m); n->m_len = m->m_len; if (m->m_flags & M_EXT) { n->m_data = m->m_data; n->m_ext = m->m_ext; n->m_flags |= M_EXT; MEXT_ADD_REF(m); } else { bcopy(mtod(m, char *), mtod(n, char *), n->m_len); } m = m->m_next; while (m) { MGET(o, how, m->m_type); if (!o) goto nospace; n->m_next = o; n = n->m_next; n->m_len = m->m_len; if (m->m_flags & M_EXT) { n->m_data = m->m_data; n->m_ext = m->m_ext; n->m_flags |= M_EXT; MEXT_ADD_REF(m); } else { bcopy(mtod(m, char *), mtod(n, char *), n->m_len); } m = m->m_next; } return top; nospace: m_freem(top); MCFail++; return 0; } /* * Copy data from an mbuf chain starting "off" bytes from the beginning, * continuing for "len" bytes, into the indicated buffer. */ void m_copydata(m, off, len, cp) register struct mbuf *m; register int off; register int len; caddr_t cp; { register unsigned count; KASSERT(off >= 0, ("m_copydata, negative off %d", off)); KASSERT(len >= 0, ("m_copydata, negative len %d", len)); while (off > 0) { KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); count = min(m->m_len - off, len); bcopy(mtod(m, caddr_t) + off, cp, count); len -= count; cp += count; off = 0; m = m->m_next; } } /* * Copy a packet header mbuf chain into a completely new chain, including * copying any mbuf clusters. Use this instead of m_copypacket() when * you need a writable copy of an mbuf chain. */ struct mbuf * m_dup(m, how) struct mbuf *m; int how; { struct mbuf **p, *top = NULL; int remain, moff, nsize; /* Sanity check */ if (m == NULL) return (0); KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __FUNCTION__)); /* While there's more data, get a new mbuf, tack it on, and fill it */ remain = m->m_pkthdr.len; moff = 0; p = ⊤ while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ struct mbuf *n; /* Get the next new mbuf */ MGET(n, how, m->m_type); if (n == NULL) goto nospace; if (top == NULL) { /* first one, must be PKTHDR */ M_COPY_PKTHDR(n, m); nsize = MHLEN; } else /* not the first one */ nsize = MLEN; if (remain >= MINCLSIZE) { MCLGET(n, how); if ((n->m_flags & M_EXT) == 0) { (void)m_free(n); goto nospace; } nsize = MCLBYTES; } n->m_len = 0; /* Link it into the new chain */ *p = n; p = &n->m_next; /* Copy data from original mbuf(s) into new mbuf */ while (n->m_len < nsize && m != NULL) { int chunk = min(nsize - n->m_len, m->m_len - moff); bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); moff += chunk; n->m_len += chunk; remain -= chunk; if (moff == m->m_len) { m = m->m_next; moff = 0; } } /* Check correct total mbuf length */ KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), ("%s: bogus m_pkthdr.len", __FUNCTION__)); } return (top); nospace: m_freem(top); MCFail++; return (0); } /* * Concatenate mbuf chain n to m. * Both chains must be of the same type (e.g. MT_DATA). * Any m_pkthdr is not updated. */ void m_cat(m, n) register struct mbuf *m, *n; { while (m->m_next) m = m->m_next; while (n) { if (m->m_flags & M_EXT || m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { /* just join the two chains */ m->m_next = n; return; } /* splat the data from one into the other */ bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, (u_int)n->m_len); m->m_len += n->m_len; n = m_free(n); } } void m_adj(mp, req_len) struct mbuf *mp; int req_len; { register int len = req_len; register struct mbuf *m; register int count; if ((m = mp) == NULL) return; if (len >= 0) { /* * Trim from head. */ while (m != NULL && len > 0) { if (m->m_len <= len) { len -= m->m_len; m->m_len = 0; m = m->m_next; } else { m->m_len -= len; m->m_data += len; len = 0; } } m = mp; if (mp->m_flags & M_PKTHDR) m->m_pkthdr.len -= (req_len - len); } else { /* * Trim from tail. Scan the mbuf chain, * calculating its length and finding the last mbuf. * If the adjustment only affects this mbuf, then just * adjust and return. Otherwise, rescan and truncate * after the remaining size. */ len = -len; count = 0; for (;;) { count += m->m_len; if (m->m_next == (struct mbuf *)0) break; m = m->m_next; } if (m->m_len >= len) { m->m_len -= len; if (mp->m_flags & M_PKTHDR) mp->m_pkthdr.len -= len; return; } count -= len; if (count < 0) count = 0; /* * Correct length for chain is "count". * Find the mbuf with last data, adjust its length, * and toss data from remaining mbufs on chain. */ m = mp; if (m->m_flags & M_PKTHDR) m->m_pkthdr.len = count; for (; m; m = m->m_next) { if (m->m_len >= count) { m->m_len = count; break; } count -= m->m_len; } while (m->m_next) (m = m->m_next) ->m_len = 0; } } /* * Rearange an mbuf chain so that len bytes are contiguous * and in the data area of an mbuf (so that mtod and dtom * will work for a structure of size len). Returns the resulting * mbuf chain on success, frees it and returns null on failure. * If there is room, it will add up to max_protohdr-len extra bytes to the * contiguous region in an attempt to avoid being called next time. */ #define MPFail (mbstat.m_mpfail) struct mbuf * m_pullup(n, len) register struct mbuf *n; int len; { register struct mbuf *m; register int count; int space; /* * If first mbuf has no cluster, and has room for len bytes * without shifting current data, pullup into it, * otherwise allocate a new mbuf to prepend to the chain. */ if ((n->m_flags & M_EXT) == 0 && n->m_data + len < &n->m_dat[MLEN] && n->m_next) { if (n->m_len >= len) return (n); m = n; n = n->m_next; len -= m->m_len; } else { if (len > MHLEN) goto bad; MGET(m, M_DONTWAIT, n->m_type); if (m == 0) goto bad; m->m_len = 0; if (n->m_flags & M_PKTHDR) { M_COPY_PKTHDR(m, n); n->m_flags &= ~M_PKTHDR; } } space = &m->m_dat[MLEN] - (m->m_data + m->m_len); do { count = min(min(max(len, max_protohdr), space), n->m_len); bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, (unsigned)count); len -= count; m->m_len += count; n->m_len -= count; space -= count; if (n->m_len) n->m_data += count; else n = m_free(n); } while (len > 0 && n); if (len > 0) { (void) m_free(m); goto bad; } m->m_next = n; return (m); bad: m_freem(n); MPFail++; return (0); } /* * Partition an mbuf chain in two pieces, returning the tail -- * all but the first len0 bytes. In case of failure, it returns NULL and * attempts to restore the chain to its original state. */ struct mbuf * m_split(m0, len0, wait) register struct mbuf *m0; int len0, wait; { register struct mbuf *m, *n; unsigned len = len0, remain; for (m = m0; m && len > m->m_len; m = m->m_next) len -= m->m_len; if (m == 0) return (0); remain = m->m_len - len; if (m0->m_flags & M_PKTHDR) { MGETHDR(n, wait, m0->m_type); if (n == 0) return (0); n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; n->m_pkthdr.len = m0->m_pkthdr.len - len0; m0->m_pkthdr.len = len0; if (m->m_flags & M_EXT) goto extpacket; if (remain > MHLEN) { /* m can't be the lead packet */ MH_ALIGN(n, 0); n->m_next = m_split(m, len, wait); if (n->m_next == 0) { (void) m_free(n); return (0); } else return (n); } else MH_ALIGN(n, remain); } else if (remain == 0) { n = m->m_next; m->m_next = 0; return (n); } else { MGET(n, wait, m->m_type); if (n == 0) return (0); M_ALIGN(n, remain); } extpacket: if (m->m_flags & M_EXT) { n->m_flags |= M_EXT; n->m_ext = m->m_ext; MEXT_ADD_REF(m); m->m_ext.ext_size = 0; /* For Accounting XXXXXX danger */ n->m_data = m->m_data + len; } else { bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); } n->m_len = remain; m->m_len = len; n->m_next = m->m_next; m->m_next = 0; return (n); } /* * Routine to copy from device local memory into mbufs. */ struct mbuf * m_devget(buf, totlen, off0, ifp, copy) char *buf; int totlen, off0; struct ifnet *ifp; void (*copy) __P((char *from, caddr_t to, u_int len)); { register struct mbuf *m; struct mbuf *top = 0, **mp = ⊤ register int off = off0, len; register char *cp; char *epkt; cp = buf; epkt = cp + totlen; if (off) { cp += off + 2 * sizeof(u_short); totlen -= 2 * sizeof(u_short); } MGETHDR(m, M_DONTWAIT, MT_DATA); if (m == 0) return (0); m->m_pkthdr.rcvif = ifp; m->m_pkthdr.len = totlen; m->m_len = MHLEN; while (totlen > 0) { if (top) { MGET(m, M_DONTWAIT, MT_DATA); if (m == 0) { m_freem(top); return (0); } m->m_len = MLEN; } len = min(totlen, epkt - cp); if (len >= MINCLSIZE) { MCLGET(m, M_DONTWAIT); if (m->m_flags & M_EXT) m->m_len = len = min(len, MCLBYTES); else len = m->m_len; } else { /* * Place initial small packet/header at end of mbuf. */ if (len < m->m_len) { if (top == 0 && len + max_linkhdr <= m->m_len) m->m_data += max_linkhdr; m->m_len = len; } else len = m->m_len; } if (copy) copy(cp, mtod(m, caddr_t), (unsigned)len); else bcopy(cp, mtod(m, caddr_t), (unsigned)len); cp += len; *mp = m; mp = &m->m_next; totlen -= len; if (cp == epkt) cp = buf; } return (top); } /* * Copy data from a buffer back into the indicated mbuf chain, * starting "off" bytes from the beginning, extending the mbuf * chain if necessary. */ void m_copyback(m0, off, len, cp) struct mbuf *m0; register int off; register int len; caddr_t cp; { register int mlen; register struct mbuf *m = m0, *n; int totlen = 0; if (m0 == 0) return; while (off > (mlen = m->m_len)) { off -= mlen; totlen += mlen; if (m->m_next == 0) { n = m_getclr(M_DONTWAIT, m->m_type); if (n == 0) goto out; n->m_len = min(MLEN, len + off); m->m_next = n; } m = m->m_next; } while (len > 0) { mlen = min (m->m_len - off, len); bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen); cp += mlen; len -= mlen; mlen += off; off = 0; totlen += mlen; if (len == 0) break; if (m->m_next == 0) { n = m_get(M_DONTWAIT, m->m_type); if (n == 0) break; n->m_len = min(MLEN, len); m->m_next = n; } m = m->m_next; } out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) m->m_pkthdr.len = totlen; } void m_print(const struct mbuf *m) { int len; const struct mbuf *m2; len = m->m_pkthdr.len; m2 = m; while (len) { printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-"); len -= m2->m_len; m2 = m2->m_next; } return; }