diff options
Diffstat (limited to 'sys/kern/uipc_mbuf.c')
| -rw-r--r-- | sys/kern/uipc_mbuf.c | 1165 |
1 files changed, 1165 insertions, 0 deletions
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c new file mode 100644 index 0000000..ca43324 --- /dev/null +++ b/sys/kern/uipc_mbuf.c @@ -0,0 +1,1165 @@ +/* + * 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 <sys/param.h> +#include <sys/systm.h> +#include <sys/malloc.h> +#include <sys/mbuf.h> +#include <sys/kernel.h> +#include <sys/sysctl.h> +#include <sys/domain.h> +#include <sys/protosw.h> + +#include <vm/vm.h> +#include <vm/vm_kern.h> +#include <vm/vm_extern.h> + +#ifdef INVARIANTS +#include <machine/cpu.h> +#endif + +static void mbinit __P((void *)); +SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) + +struct mbuf *mbutl; +char *mclrefcnt; +struct mbstat mbstat; +struct mbuf *mmbfree; +union mcluster *mclfree; +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_RW, &mbstat, mbstat, ""); +SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RD, + &nmbclusters, 0, "Maximum number of mbuf clusters avaliable"); +#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); /* XXX fixup? */ + +static void m_reclaim __P((void)); + +/* "number of clusters of pages" */ +#define NCL_INIT 1 + +#define NMB_INIT 16 + +/* ARGSUSED*/ +static void +mbinit(dummy) + void *dummy; +{ + int s; + + mmbfree = NULL; mclfree = 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_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"); +} + +/* + * 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; + + /* + * 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; + 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; + + /* + * 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 { + 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; + if(!m->m_ext.ext_ref) + mclrefcnt[mtocl(m->m_ext.ext_buf)]++; + else + (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, + m->m_ext.ext_size); + n->m_ext = m->m_ext; + n->m_flags |= M_EXT; + } 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; + if(!m->m_ext.ext_ref) + mclrefcnt[mtocl(m->m_ext.ext_buf)]++; + else + (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, + m->m_ext.ext_size); + n->m_ext = m->m_ext; + n->m_flags |= M_EXT; + } 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; + if(!m->m_ext.ext_ref) + mclrefcnt[mtocl(m->m_ext.ext_buf)]++; + else + (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, + m->m_ext.ext_size); + n->m_ext = m->m_ext; + n->m_flags |= M_EXT; + } 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; + if(!m->m_ext.ext_ref) + mclrefcnt[mtocl(m->m_ext.ext_buf)]++; + else + (*(m->m_ext.ext_ref))(m->m_ext.ext_buf, + m->m_ext.ext_size); + 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; + 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; +} |
