063d811465
Discussed with: rwatson
1260 lines
29 KiB
C
1260 lines
29 KiB
C
/*
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* Copyright (c) 1982, 1986, 1988, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_mac.h"
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#include "opt_param.h"
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#include "opt_mbuf_stress_test.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/limits.h>
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#include <sys/lock.h>
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#include <sys/mac.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/sysctl.h>
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#include <sys/domain.h>
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#include <sys/protosw.h>
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#include <sys/uio.h>
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int max_linkhdr;
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int max_protohdr;
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int max_hdr;
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int max_datalen;
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#ifdef MBUF_STRESS_TEST
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int m_defragpackets;
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int m_defragbytes;
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int m_defraguseless;
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int m_defragfailure;
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int m_defragrandomfailures;
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#endif
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/*
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* sysctl(8) exported objects
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*/
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SYSCTL_DECL(_kern_ipc);
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SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW,
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&max_linkhdr, 0, "");
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SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW,
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&max_protohdr, 0, "");
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SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, "");
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SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
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&max_datalen, 0, "");
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#ifdef MBUF_STRESS_TEST
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SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
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&m_defragpackets, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
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&m_defragbytes, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
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&m_defraguseless, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
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&m_defragfailure, 0, "");
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SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
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&m_defragrandomfailures, 0, "");
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#endif
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/*
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* Malloc-type for external ext_buf ref counts.
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*/
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MALLOC_DEFINE(M_MBUF, "mbextcnt", "mbuf external ref counts");
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/*
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* Allocate a given length worth of mbufs and/or clusters (whatever fits
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* best) and return a pointer to the top of the allocated chain. If an
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* existing mbuf chain is provided, then we will append the new chain
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* to the existing one but still return the top of the newly allocated
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* chain.
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*/
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struct mbuf *
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m_getm(struct mbuf *m, int len, int how, short type)
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{
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struct mbuf *mb, *top, *cur, *mtail;
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int num, rem;
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int i;
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KASSERT(len >= 0, ("m_getm(): len is < 0"));
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MBUF_CHECKSLEEP(how);
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/* If m != NULL, we will append to the end of that chain. */
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if (m != NULL)
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for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next);
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else
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mtail = NULL;
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/*
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* Calculate how many mbufs+clusters ("packets") we need and how much
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* leftover there is after that and allocate the first mbuf+cluster
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* if required.
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*/
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num = len / MCLBYTES;
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rem = len % MCLBYTES;
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top = cur = NULL;
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if (num > 0) {
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if ((top = cur = m_getcl(how, type, 0)) == NULL)
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goto failed;
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top->m_len = 0;
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}
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num--;
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for (i = 0; i < num; i++) {
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mb = m_getcl(how, type, 0);
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if (mb == NULL)
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goto failed;
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mb->m_len = 0;
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cur = (cur->m_next = mb);
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}
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if (rem > 0) {
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mb = (rem > MINCLSIZE) ?
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m_getcl(how, type, 0) : m_get(how, type);
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if (mb == NULL)
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goto failed;
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mb->m_len = 0;
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if (cur == NULL)
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top = mb;
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else
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cur->m_next = mb;
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}
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if (mtail != NULL)
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mtail->m_next = top;
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return top;
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failed:
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if (top != NULL)
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m_freem(top);
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return NULL;
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}
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/*
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* Free an entire chain of mbufs and associated external buffers, if
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* applicable.
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*/
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void
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m_freem(struct mbuf *mb)
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{
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while (mb != NULL)
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mb = m_free(mb);
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}
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/*-
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* Configure a provided mbuf to refer to the provided external storage
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* buffer and setup a reference count for said buffer. If the setting
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* up of the reference count fails, the M_EXT bit will not be set. If
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* successfull, the M_EXT bit is set in the mbuf's flags.
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*
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* Arguments:
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* mb The existing mbuf to which to attach the provided buffer.
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* buf The address of the provided external storage buffer.
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* size The size of the provided buffer.
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* freef A pointer to a routine that is responsible for freeing the
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* provided external storage buffer.
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* args A pointer to an argument structure (of any type) to be passed
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* to the provided freef routine (may be NULL).
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* flags Any other flags to be passed to the provided mbuf.
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* type The type that the external storage buffer should be
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* labeled with.
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*
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* Returns:
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* Nothing.
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*/
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void
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m_extadd(struct mbuf *mb, caddr_t buf, u_int size,
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void (*freef)(void *, void *), void *args, int flags, int type)
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{
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u_int *ref_cnt = NULL;
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/* XXX Shouldn't be adding EXT_CLUSTER with this API */
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if (type == EXT_CLUSTER)
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ref_cnt = (u_int *)uma_find_refcnt(zone_clust,
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mb->m_ext.ext_buf);
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else if (type == EXT_EXTREF)
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ref_cnt = mb->m_ext.ref_cnt;
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mb->m_ext.ref_cnt = (ref_cnt == NULL) ?
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malloc(sizeof(u_int), M_MBUF, M_NOWAIT) : (u_int *)ref_cnt;
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if (mb->m_ext.ref_cnt != NULL) {
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*(mb->m_ext.ref_cnt) = 1;
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mb->m_flags |= (M_EXT | flags);
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mb->m_ext.ext_buf = buf;
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mb->m_data = mb->m_ext.ext_buf;
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mb->m_ext.ext_size = size;
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mb->m_ext.ext_free = freef;
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mb->m_ext.ext_args = args;
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mb->m_ext.ext_type = type;
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}
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}
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/*
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* Non-directly-exported function to clean up after mbufs with M_EXT
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* storage attached to them if the reference count hits 0.
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*/
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void
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mb_free_ext(struct mbuf *m)
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{
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u_int cnt;
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/*
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* This is tricky. We need to make sure to decrement the
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* refcount in a safe way but to also clean up if we're the
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* last reference. This method seems to do it without race.
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*/
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do {
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cnt = *(m->m_ext.ref_cnt);
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if (atomic_cmpset_int(m->m_ext.ref_cnt, cnt, cnt - 1)) {
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if (cnt == 1) {
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/*
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* Do the free, should be safe.
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*/
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if (m->m_ext.ext_type == EXT_PACKET) {
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uma_zfree(zone_pack, m);
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return;
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} else if (m->m_ext.ext_type == EXT_CLUSTER) {
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uma_zfree(zone_clust, m->m_ext.ext_buf);
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m->m_ext.ext_buf = NULL;
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} else {
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(*(m->m_ext.ext_free))(m->m_ext.ext_buf,
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m->m_ext.ext_args);
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if (m->m_ext.ext_type != EXT_EXTREF)
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free(m->m_ext.ref_cnt, M_MBUF);
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m->m_ext.ext_buf = NULL;
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}
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}
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/* Decrement (and potentially free) done, safely. */
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break;
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}
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} while (1);
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uma_zfree(zone_mbuf, m);
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}
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/*
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* "Move" mbuf pkthdr from "from" to "to".
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* "from" must have M_PKTHDR set, and "to" must be empty.
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*/
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void
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m_move_pkthdr(struct mbuf *to, struct mbuf *from)
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{
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#if 0
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/* see below for why these are not enabled */
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M_ASSERTPKTHDR(to);
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/* Note: with MAC, this may not be a good assertion. */
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KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags),
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("m_move_pkthdr: to has tags"));
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#endif
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KASSERT((to->m_flags & M_EXT) == 0, ("m_move_pkthdr: to has cluster"));
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#ifdef MAC
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/*
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* XXXMAC: It could be this should also occur for non-MAC?
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*/
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if (to->m_flags & M_PKTHDR)
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m_tag_delete_chain(to, NULL);
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#endif
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to->m_flags = from->m_flags & M_COPYFLAGS;
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to->m_data = to->m_pktdat;
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to->m_pkthdr = from->m_pkthdr; /* especially tags */
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SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */
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from->m_flags &= ~M_PKTHDR;
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}
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/*
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* Duplicate "from"'s mbuf pkthdr in "to".
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* "from" must have M_PKTHDR set, and "to" must be empty.
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* In particular, this does a deep copy of the packet tags.
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*/
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int
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m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how)
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{
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#if 0
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/*
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* The mbuf allocator only initializes the pkthdr
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* when the mbuf is allocated with MGETHDR. Many users
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* (e.g. m_copy*, m_prepend) use MGET and then
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* smash the pkthdr as needed causing these
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* assertions to trip. For now just disable them.
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*/
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M_ASSERTPKTHDR(to);
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/* Note: with MAC, this may not be a good assertion. */
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KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags"));
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#endif
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MBUF_CHECKSLEEP(how);
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#ifdef MAC
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if (to->m_flags & M_PKTHDR)
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m_tag_delete_chain(to, NULL);
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#endif
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to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
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if ((to->m_flags & M_EXT) == 0)
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to->m_data = to->m_pktdat;
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to->m_pkthdr = from->m_pkthdr;
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SLIST_INIT(&to->m_pkthdr.tags);
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return (m_tag_copy_chain(to, from, MBTOM(how)));
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}
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|
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/*
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* Lesser-used path for M_PREPEND:
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* allocate new mbuf to prepend to chain,
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* copy junk along.
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*/
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struct mbuf *
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m_prepend(struct mbuf *m, int len, int how)
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{
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struct mbuf *mn;
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MBUF_CHECKSLEEP(how);
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if (m->m_flags & M_PKTHDR)
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MGETHDR(mn, how, m->m_type);
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else
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MGET(mn, how, m->m_type);
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if (mn == NULL) {
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m_freem(m);
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return (NULL);
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}
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if (m->m_flags & M_PKTHDR)
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M_MOVE_PKTHDR(mn, m);
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mn->m_next = m;
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m = mn;
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if (len < MHLEN)
|
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MH_ALIGN(m, len);
|
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m->m_len = len;
|
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return (m);
|
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}
|
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|
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/*
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* Make a copy of an mbuf chain starting "off0" bytes from the beginning,
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* continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
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* The wait parameter is a choice of M_TRYWAIT/M_DONTWAIT from caller.
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* Note that the copy is read-only, because clusters are not copied,
|
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* only their reference counts are incremented.
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*/
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struct mbuf *
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m_copym(struct mbuf *m, int off0, int len, int wait)
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{
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struct mbuf *n, **np;
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int off = off0;
|
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struct mbuf *top;
|
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int copyhdr = 0;
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|
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KASSERT(off >= 0, ("m_copym, negative off %d", off));
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KASSERT(len >= 0, ("m_copym, negative len %d", len));
|
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MBUF_CHECKSLEEP(wait);
|
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if (off == 0 && m->m_flags & M_PKTHDR)
|
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copyhdr = 1;
|
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while (off > 0) {
|
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KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
|
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if (off < m->m_len)
|
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break;
|
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off -= m->m_len;
|
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m = m->m_next;
|
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}
|
|
np = ⊤
|
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top = 0;
|
|
while (len > 0) {
|
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if (m == NULL) {
|
|
KASSERT(len == M_COPYALL,
|
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("m_copym, length > size of mbuf chain"));
|
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break;
|
|
}
|
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if (copyhdr)
|
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MGETHDR(n, wait, m->m_type);
|
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else
|
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MGET(n, wait, m->m_type);
|
|
*np = n;
|
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if (n == NULL)
|
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goto nospace;
|
|
if (copyhdr) {
|
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if (!m_dup_pkthdr(n, m, wait))
|
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goto nospace;
|
|
if (len == M_COPYALL)
|
|
n->m_pkthdr.len -= off0;
|
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else
|
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n->m_pkthdr.len = len;
|
|
copyhdr = 0;
|
|
}
|
|
n->m_len = min(len, m->m_len - off);
|
|
if (m->m_flags & M_EXT) {
|
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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),
|
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(u_int)n->m_len);
|
|
if (len != M_COPYALL)
|
|
len -= n->m_len;
|
|
off = 0;
|
|
m = m->m_next;
|
|
np = &n->m_next;
|
|
}
|
|
if (top == NULL)
|
|
mbstat.m_mcfail++; /* XXX: No consistency. */
|
|
|
|
return (top);
|
|
nospace:
|
|
m_freem(top);
|
|
mbstat.m_mcfail++; /* XXX: No consistency. */
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
* Preserve alignment of the first mbuf so if the creator has left
|
|
* some room at the beginning (e.g. for inserting protocol headers)
|
|
* the copies still have the room available.
|
|
*/
|
|
struct mbuf *
|
|
m_copypacket(struct mbuf *m, int how)
|
|
{
|
|
struct mbuf *top, *n, *o;
|
|
|
|
MBUF_CHECKSLEEP(how);
|
|
MGET(n, how, m->m_type);
|
|
top = n;
|
|
if (n == NULL)
|
|
goto nospace;
|
|
|
|
if (!m_dup_pkthdr(n, m, how))
|
|
goto nospace;
|
|
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 {
|
|
n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
|
|
bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
|
|
}
|
|
|
|
m = m->m_next;
|
|
while (m) {
|
|
MGET(o, how, m->m_type);
|
|
if (o == NULL)
|
|
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);
|
|
mbstat.m_mcfail++; /* XXX: No consistency. */
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Copy data from an mbuf chain starting "off" bytes from the beginning,
|
|
* continuing for "len" bytes, into the indicated buffer.
|
|
*/
|
|
void
|
|
m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
|
|
{
|
|
u_int 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(struct mbuf *m, int how)
|
|
{
|
|
struct mbuf **p, *top = NULL;
|
|
int remain, moff, nsize;
|
|
|
|
MBUF_CHECKSLEEP(how);
|
|
/* Sanity check */
|
|
if (m == NULL)
|
|
return (NULL);
|
|
M_ASSERTPKTHDR(m);
|
|
|
|
/* 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 */
|
|
if (remain >= MINCLSIZE) {
|
|
n = m_getcl(how, m->m_type, 0);
|
|
nsize = MCLBYTES;
|
|
} else {
|
|
n = m_get(how, m->m_type);
|
|
nsize = MLEN;
|
|
}
|
|
if (n == NULL)
|
|
goto nospace;
|
|
|
|
if (top == NULL) { /* First one, must be PKTHDR */
|
|
if (!m_dup_pkthdr(n, m, how)) {
|
|
m_free(n);
|
|
goto nospace;
|
|
}
|
|
nsize = MHLEN;
|
|
}
|
|
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", __func__));
|
|
}
|
|
return (top);
|
|
|
|
nospace:
|
|
m_freem(top);
|
|
mbstat.m_mcfail++; /* XXX: No consistency. */
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* 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(struct mbuf *m, struct mbuf *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(struct mbuf *mp, int req_len)
|
|
{
|
|
int len = req_len;
|
|
struct mbuf *m;
|
|
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.
|
|
*/
|
|
struct mbuf *
|
|
m_pullup(struct mbuf *n, int len)
|
|
{
|
|
struct mbuf *m;
|
|
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 == NULL)
|
|
goto bad;
|
|
m->m_len = 0;
|
|
if (n->m_flags & M_PKTHDR)
|
|
M_MOVE_PKTHDR(m, n);
|
|
}
|
|
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,
|
|
(u_int)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);
|
|
mbstat.m_mpfail++; /* XXX: No consistency. */
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* Note that the resulting mbufs might be read-only, because the new
|
|
* mbuf can end up sharing an mbuf cluster with the original mbuf if
|
|
* the "breaking point" happens to lie within a cluster mbuf. Use the
|
|
* M_WRITABLE() macro to check for this case.
|
|
*/
|
|
struct mbuf *
|
|
m_split(struct mbuf *m0, int len0, int wait)
|
|
{
|
|
struct mbuf *m, *n;
|
|
u_int len = len0, remain;
|
|
|
|
MBUF_CHECKSLEEP(wait);
|
|
for (m = m0; m && len > m->m_len; m = m->m_next)
|
|
len -= m->m_len;
|
|
if (m == NULL)
|
|
return (NULL);
|
|
remain = m->m_len - len;
|
|
if (m0->m_flags & M_PKTHDR) {
|
|
MGETHDR(n, wait, m0->m_type);
|
|
if (n == NULL)
|
|
return (NULL);
|
|
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 == NULL) {
|
|
(void) m_free(n);
|
|
return (NULL);
|
|
} else {
|
|
n->m_len = 0;
|
|
return (n);
|
|
}
|
|
} else
|
|
MH_ALIGN(n, remain);
|
|
} else if (remain == 0) {
|
|
n = m->m_next;
|
|
m->m_next = NULL;
|
|
return (n);
|
|
} else {
|
|
MGET(n, wait, m->m_type);
|
|
if (n == NULL)
|
|
return (NULL);
|
|
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);
|
|
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 = NULL;
|
|
return (n);
|
|
}
|
|
/*
|
|
* Routine to copy from device local memory into mbufs.
|
|
* Note that `off' argument is offset into first mbuf of target chain from
|
|
* which to begin copying the data to.
|
|
*/
|
|
struct mbuf *
|
|
m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
|
|
void (*copy)(char *from, caddr_t to, u_int len))
|
|
{
|
|
struct mbuf *m;
|
|
struct mbuf *top = NULL, **mp = ⊤
|
|
int len;
|
|
|
|
if (off < 0 || off > MHLEN)
|
|
return (NULL);
|
|
|
|
while (totlen > 0) {
|
|
if (top == NULL) { /* First one, must be PKTHDR */
|
|
if (totlen + off >= MINCLSIZE) {
|
|
m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
|
|
len = MCLBYTES;
|
|
} else {
|
|
m = m_gethdr(M_DONTWAIT, MT_DATA);
|
|
len = MHLEN;
|
|
|
|
/* Place initial small packet/header at end of mbuf */
|
|
if (m && totlen + off + max_linkhdr <= MLEN) {
|
|
m->m_data += max_linkhdr;
|
|
len -= max_linkhdr;
|
|
}
|
|
}
|
|
if (m == NULL)
|
|
return NULL;
|
|
m->m_pkthdr.rcvif = ifp;
|
|
m->m_pkthdr.len = totlen;
|
|
} else {
|
|
if (totlen + off >= MINCLSIZE) {
|
|
m = m_getcl(M_DONTWAIT, MT_DATA, 0);
|
|
len = MCLBYTES;
|
|
} else {
|
|
m = m_get(M_DONTWAIT, MT_DATA);
|
|
len = MLEN;
|
|
}
|
|
if (m == NULL) {
|
|
m_freem(top);
|
|
return NULL;
|
|
}
|
|
}
|
|
if (off) {
|
|
m->m_data += off;
|
|
len -= off;
|
|
off = 0;
|
|
}
|
|
m->m_len = len = min(totlen, len);
|
|
if (copy)
|
|
copy(buf, mtod(m, caddr_t), (u_int)len);
|
|
else
|
|
bcopy(buf, mtod(m, caddr_t), (u_int)len);
|
|
buf += len;
|
|
*mp = m;
|
|
mp = &m->m_next;
|
|
totlen -= len;
|
|
}
|
|
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(struct mbuf *m0, int off, int len, c_caddr_t cp)
|
|
{
|
|
int mlen;
|
|
struct mbuf *m = m0, *n;
|
|
int totlen = 0;
|
|
|
|
if (m0 == NULL)
|
|
return;
|
|
while (off > (mlen = m->m_len)) {
|
|
off -= mlen;
|
|
totlen += mlen;
|
|
if (m->m_next == NULL) {
|
|
n = m_get(M_DONTWAIT, m->m_type);
|
|
if (n == NULL)
|
|
goto out;
|
|
bzero(mtod(n, caddr_t), MLEN);
|
|
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), (u_int)mlen);
|
|
cp += mlen;
|
|
len -= mlen;
|
|
mlen += off;
|
|
off = 0;
|
|
totlen += mlen;
|
|
if (len == 0)
|
|
break;
|
|
if (m->m_next == NULL) {
|
|
n = m_get(M_DONTWAIT, m->m_type);
|
|
if (n == NULL)
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Apply function f to the data in an mbuf chain starting "off" bytes from
|
|
* the beginning, continuing for "len" bytes.
|
|
*/
|
|
int
|
|
m_apply(struct mbuf *m, int off, int len,
|
|
int (*f)(void *, void *, u_int), void *arg)
|
|
{
|
|
u_int count;
|
|
int rval;
|
|
|
|
KASSERT(off >= 0, ("m_apply, negative off %d", off));
|
|
KASSERT(len >= 0, ("m_apply, negative len %d", len));
|
|
while (off > 0) {
|
|
KASSERT(m != NULL, ("m_apply, 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_apply, offset > size of mbuf chain"));
|
|
count = min(m->m_len - off, len);
|
|
rval = (*f)(arg, mtod(m, caddr_t) + off, count);
|
|
if (rval)
|
|
return (rval);
|
|
len -= count;
|
|
off = 0;
|
|
m = m->m_next;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Return a pointer to mbuf/offset of location in mbuf chain.
|
|
*/
|
|
struct mbuf *
|
|
m_getptr(struct mbuf *m, int loc, int *off)
|
|
{
|
|
|
|
while (loc >= 0) {
|
|
/* Normal end of search. */
|
|
if (m->m_len > loc) {
|
|
*off = loc;
|
|
return (m);
|
|
} else {
|
|
loc -= m->m_len;
|
|
if (m->m_next == NULL) {
|
|
if (loc == 0) {
|
|
/* Point at the end of valid data. */
|
|
*off = m->m_len;
|
|
return (m);
|
|
}
|
|
return (NULL);
|
|
}
|
|
m = m->m_next;
|
|
}
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
u_int
|
|
m_fixhdr(struct mbuf *m0)
|
|
{
|
|
u_int len;
|
|
|
|
len = m_length(m0, NULL);
|
|
m0->m_pkthdr.len = len;
|
|
return (len);
|
|
}
|
|
|
|
u_int
|
|
m_length(struct mbuf *m0, struct mbuf **last)
|
|
{
|
|
struct mbuf *m;
|
|
u_int len;
|
|
|
|
len = 0;
|
|
for (m = m0; m != NULL; m = m->m_next) {
|
|
len += m->m_len;
|
|
if (m->m_next == NULL)
|
|
break;
|
|
}
|
|
if (last != NULL)
|
|
*last = m;
|
|
return (len);
|
|
}
|
|
|
|
/*
|
|
* Defragment a mbuf chain, returning the shortest possible
|
|
* chain of mbufs and clusters. If allocation fails and
|
|
* this cannot be completed, NULL will be returned, but
|
|
* the passed in chain will be unchanged. Upon success,
|
|
* the original chain will be freed, and the new chain
|
|
* will be returned.
|
|
*
|
|
* If a non-packet header is passed in, the original
|
|
* mbuf (chain?) will be returned unharmed.
|
|
*/
|
|
struct mbuf *
|
|
m_defrag(struct mbuf *m0, int how)
|
|
{
|
|
struct mbuf *m_new = NULL, *m_final = NULL;
|
|
int progress = 0, length;
|
|
|
|
MBUF_CHECKSLEEP(how);
|
|
if (!(m0->m_flags & M_PKTHDR))
|
|
return (m0);
|
|
|
|
m_fixhdr(m0); /* Needed sanity check */
|
|
|
|
#ifdef MBUF_STRESS_TEST
|
|
if (m_defragrandomfailures) {
|
|
int temp = arc4random() & 0xff;
|
|
if (temp == 0xba)
|
|
goto nospace;
|
|
}
|
|
#endif
|
|
|
|
if (m0->m_pkthdr.len > MHLEN)
|
|
m_final = m_getcl(how, MT_DATA, M_PKTHDR);
|
|
else
|
|
m_final = m_gethdr(how, MT_DATA);
|
|
|
|
if (m_final == NULL)
|
|
goto nospace;
|
|
|
|
if (m_dup_pkthdr(m_final, m0, how) == 0)
|
|
goto nospace;
|
|
|
|
m_new = m_final;
|
|
|
|
while (progress < m0->m_pkthdr.len) {
|
|
length = m0->m_pkthdr.len - progress;
|
|
if (length > MCLBYTES)
|
|
length = MCLBYTES;
|
|
|
|
if (m_new == NULL) {
|
|
if (length > MLEN)
|
|
m_new = m_getcl(how, MT_DATA, 0);
|
|
else
|
|
m_new = m_get(how, MT_DATA);
|
|
if (m_new == NULL)
|
|
goto nospace;
|
|
}
|
|
|
|
m_copydata(m0, progress, length, mtod(m_new, caddr_t));
|
|
progress += length;
|
|
m_new->m_len = length;
|
|
if (m_new != m_final)
|
|
m_cat(m_final, m_new);
|
|
m_new = NULL;
|
|
}
|
|
#ifdef MBUF_STRESS_TEST
|
|
if (m0->m_next == NULL)
|
|
m_defraguseless++;
|
|
#endif
|
|
m_freem(m0);
|
|
m0 = m_final;
|
|
#ifdef MBUF_STRESS_TEST
|
|
m_defragpackets++;
|
|
m_defragbytes += m0->m_pkthdr.len;
|
|
#endif
|
|
return (m0);
|
|
nospace:
|
|
#ifdef MBUF_STRESS_TEST
|
|
m_defragfailure++;
|
|
#endif
|
|
if (m_new)
|
|
m_free(m_new);
|
|
if (m_final)
|
|
m_freem(m_final);
|
|
return (NULL);
|
|
}
|
|
|
|
#ifdef MBUF_STRESS_TEST
|
|
|
|
/*
|
|
* Fragment an mbuf chain. There's no reason you'd ever want to do
|
|
* this in normal usage, but it's great for stress testing various
|
|
* mbuf consumers.
|
|
*
|
|
* If fragmentation is not possible, the original chain will be
|
|
* returned.
|
|
*
|
|
* Possible length values:
|
|
* 0 no fragmentation will occur
|
|
* > 0 each fragment will be of the specified length
|
|
* -1 each fragment will be the same random value in length
|
|
* -2 each fragment's length will be entirely random
|
|
* (Random values range from 1 to 256)
|
|
*/
|
|
struct mbuf *
|
|
m_fragment(struct mbuf *m0, int how, int length)
|
|
{
|
|
struct mbuf *m_new = NULL, *m_final = NULL;
|
|
int progress = 0;
|
|
|
|
if (!(m0->m_flags & M_PKTHDR))
|
|
return (m0);
|
|
|
|
if ((length == 0) || (length < -2))
|
|
return (m0);
|
|
|
|
m_fixhdr(m0); /* Needed sanity check */
|
|
|
|
m_final = m_getcl(how, MT_DATA, M_PKTHDR);
|
|
|
|
if (m_final == NULL)
|
|
goto nospace;
|
|
|
|
if (m_dup_pkthdr(m_final, m0, how) == 0)
|
|
goto nospace;
|
|
|
|
m_new = m_final;
|
|
|
|
if (length == -1)
|
|
length = 1 + (arc4random() & 255);
|
|
|
|
while (progress < m0->m_pkthdr.len) {
|
|
int fraglen;
|
|
|
|
if (length > 0)
|
|
fraglen = length;
|
|
else
|
|
fraglen = 1 + (arc4random() & 255);
|
|
if (fraglen > m0->m_pkthdr.len - progress)
|
|
fraglen = m0->m_pkthdr.len - progress;
|
|
|
|
if (fraglen > MCLBYTES)
|
|
fraglen = MCLBYTES;
|
|
|
|
if (m_new == NULL) {
|
|
m_new = m_getcl(how, MT_DATA, 0);
|
|
if (m_new == NULL)
|
|
goto nospace;
|
|
}
|
|
|
|
m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t));
|
|
progress += fraglen;
|
|
m_new->m_len = fraglen;
|
|
if (m_new != m_final)
|
|
m_cat(m_final, m_new);
|
|
m_new = NULL;
|
|
}
|
|
m_freem(m0);
|
|
m0 = m_final;
|
|
return (m0);
|
|
nospace:
|
|
if (m_new)
|
|
m_free(m_new);
|
|
if (m_final)
|
|
m_freem(m_final);
|
|
/* Return the original chain on failure */
|
|
return (m0);
|
|
}
|
|
|
|
#endif
|
|
|
|
struct mbuf *
|
|
m_uiotombuf(struct uio *uio, int how, int len)
|
|
{
|
|
struct mbuf *m_new = NULL, *m_final = NULL;
|
|
int progress = 0, error = 0, length, total;
|
|
|
|
if (len > 0)
|
|
total = min(uio->uio_resid, len);
|
|
else
|
|
total = uio->uio_resid;
|
|
if (total > MHLEN)
|
|
m_final = m_getcl(how, MT_DATA, M_PKTHDR);
|
|
else
|
|
m_final = m_gethdr(how, MT_DATA);
|
|
if (m_final == NULL)
|
|
goto nospace;
|
|
m_new = m_final;
|
|
while (progress < total) {
|
|
length = total - progress;
|
|
if (length > MCLBYTES)
|
|
length = MCLBYTES;
|
|
if (m_new == NULL) {
|
|
if (length > MLEN)
|
|
m_new = m_getcl(how, MT_DATA, 0);
|
|
else
|
|
m_new = m_get(how, MT_DATA);
|
|
if (m_new == NULL)
|
|
goto nospace;
|
|
}
|
|
error = uiomove(mtod(m_new, void *), length, uio);
|
|
if (error)
|
|
goto nospace;
|
|
progress += length;
|
|
m_new->m_len = length;
|
|
if (m_new != m_final)
|
|
m_cat(m_final, m_new);
|
|
m_new = NULL;
|
|
}
|
|
m_fixhdr(m_final);
|
|
return (m_final);
|
|
nospace:
|
|
if (m_new)
|
|
m_free(m_new);
|
|
if (m_final)
|
|
m_freem(m_final);
|
|
return (NULL);
|
|
}
|