405 lines
11 KiB
C
405 lines
11 KiB
C
/* $FreeBSD$ */
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/* $KAME: uipc_mbuf2.c,v 1.31 2001/11/28 11:08:53 itojun Exp $ */
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/* $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $ */
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/*
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* Copyright (C) 1999 WIDE Project.
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* 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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* 3. Neither the name of the project 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 PROJECT 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 PROJECT 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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/*
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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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 8.4 (Berkeley) 2/14/95
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*/
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/*#define PULLDOWN_DEBUG*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/mutex.h>
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/* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
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static struct mbuf *m_dup1(struct mbuf *, int, int, int);
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/*
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* ensure that [off, off + len) is contiguous on the mbuf chain "m".
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* packet chain before "off" is kept untouched.
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* if offp == NULL, the target will start at <retval, 0> on resulting chain.
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* if offp != NULL, the target will start at <retval, *offp> on resulting chain.
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*
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* on error return (NULL return value), original "m" will be freed.
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*
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* XXX: M_TRAILINGSPACE/M_LEADINGSPACE only permitted on writable ext_buf.
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*/
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struct mbuf *
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m_pulldown(struct mbuf *m, int off, int len, int *offp)
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{
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struct mbuf *n, *o;
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int hlen, tlen, olen;
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int writable;
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/* check invalid arguments. */
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if (m == NULL)
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panic("m == NULL in m_pulldown()");
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if (len > MCLBYTES) {
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m_freem(m);
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return NULL; /* impossible */
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}
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#ifdef PULLDOWN_DEBUG
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{
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struct mbuf *t;
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printf("before:");
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for (t = m; t; t = t->m_next)
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printf(" %d", t->m_len);
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printf("\n");
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}
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#endif
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n = m;
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while (n != NULL && off > 0) {
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if (n->m_len > off)
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break;
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off -= n->m_len;
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n = n->m_next;
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}
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/* be sure to point non-empty mbuf */
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while (n != NULL && n->m_len == 0)
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n = n->m_next;
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if (!n) {
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m_freem(m);
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return NULL; /* mbuf chain too short */
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}
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/*
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* XXX: This code is flawed because it considers a "writable" mbuf
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* data region to require all of the following:
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* (i) mbuf _has_ to have M_EXT set; if it is just a regular
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* mbuf, it is still not considered "writable."
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* (ii) since mbuf has M_EXT, the ext_type _has_ to be
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* EXT_CLUSTER. Anything else makes it non-writable.
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* (iii) M_WRITABLE() must evaluate true.
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* Ideally, the requirement should only be (iii).
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*
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* If we're writable, we're sure we're writable, because the ref. count
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* cannot increase from 1, as that would require posession of mbuf
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* n by someone else (which is impossible). However, if we're _not_
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* writable, we may eventually become writable )if the ref. count drops
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* to 1), but we'll fail to notice it unless we re-evaluate
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* M_WRITABLE(). For now, we only evaluate once at the beginning and
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* live with this.
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*/
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/*
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* XXX: This is dumb. If we're just a regular mbuf with no M_EXT,
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* then we're not "writable," according to this code.
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*/
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writable = 0;
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if ((n->m_flags & M_EXT) == 0 ||
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(n->m_ext.ext_type == EXT_CLUSTER && M_WRITABLE(n)))
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writable = 1;
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/*
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* the target data is on <n, off>.
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* if we got enough data on the mbuf "n", we're done.
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*/
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if ((off == 0 || offp) && len <= n->m_len - off && writable)
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goto ok;
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/*
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* when len <= n->m_len - off and off != 0, it is a special case.
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* len bytes from <n, off> sits in single mbuf, but the caller does
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* not like the starting position (off).
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* chop the current mbuf into two pieces, set off to 0.
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*/
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if (len <= n->m_len - off) {
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o = m_dup1(n, off, n->m_len - off, M_DONTWAIT);
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if (o == NULL) {
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m_freem(m);
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return NULL; /* ENOBUFS */
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}
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n->m_len = off;
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o->m_next = n->m_next;
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n->m_next = o;
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n = n->m_next;
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off = 0;
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goto ok;
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}
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/*
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* we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
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* and construct contiguous mbuf with m_len == len.
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* note that hlen + tlen == len, and tlen > 0.
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*/
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hlen = n->m_len - off;
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tlen = len - hlen;
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/*
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* ensure that we have enough trailing data on mbuf chain.
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* if not, we can do nothing about the chain.
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*/
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olen = 0;
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for (o = n->m_next; o != NULL; o = o->m_next)
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olen += o->m_len;
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if (hlen + olen < len) {
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m_freem(m);
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return NULL; /* mbuf chain too short */
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}
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/*
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* easy cases first.
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* we need to use m_copydata() to get data from <n->m_next, 0>.
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*/
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if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
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&& writable) {
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m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
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n->m_len += tlen;
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m_adj(n->m_next, tlen);
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goto ok;
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}
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if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
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&& writable) {
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n->m_next->m_data -= hlen;
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n->m_next->m_len += hlen;
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bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
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n->m_len -= hlen;
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n = n->m_next;
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off = 0;
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goto ok;
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}
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/*
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* now, we need to do the hard way. don't m_copy as there's no room
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* on both end.
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*/
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MGET(o, M_DONTWAIT, m->m_type);
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if (o && len > MLEN) {
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MCLGET(o, M_DONTWAIT);
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if ((o->m_flags & M_EXT) == 0) {
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m_free(o);
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o = NULL;
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}
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}
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if (!o) {
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m_freem(m);
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return NULL; /* ENOBUFS */
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}
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/* get hlen from <n, off> into <o, 0> */
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o->m_len = hlen;
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bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
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n->m_len -= hlen;
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/* get tlen from <n->m_next, 0> into <o, hlen> */
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m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
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o->m_len += tlen;
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m_adj(n->m_next, tlen);
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o->m_next = n->m_next;
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n->m_next = o;
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n = o;
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off = 0;
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ok:
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#ifdef PULLDOWN_DEBUG
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{
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struct mbuf *t;
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printf("after:");
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for (t = m; t; t = t->m_next)
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printf("%c%d", t == n ? '*' : ' ', t->m_len);
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printf(" (off=%d)\n", off);
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}
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#endif
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if (offp)
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*offp = off;
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return n;
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}
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static struct mbuf *
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m_dup1(struct mbuf *m, int off, int len, int wait)
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{
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struct mbuf *n;
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int l;
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int copyhdr;
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if (len > MCLBYTES)
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return NULL;
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if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {
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copyhdr = 1;
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MGETHDR(n, wait, m->m_type);
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l = MHLEN;
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} else {
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copyhdr = 0;
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MGET(n, wait, m->m_type);
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l = MLEN;
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}
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if (n && len > l) {
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MCLGET(n, wait);
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if ((n->m_flags & M_EXT) == 0) {
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m_free(n);
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n = NULL;
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}
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}
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if (!n)
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return NULL;
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if (copyhdr)
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M_COPY_PKTHDR(n, m);
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m_copydata(m, off, len, mtod(n, caddr_t));
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return n;
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}
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/*
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* pkthdr.aux chain manipulation.
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* we don't allow clusters at this moment.
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*/
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struct mbuf *
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m_aux_add2(struct mbuf *m, int af, int type, void *p)
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{
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struct mbuf *n;
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struct mauxtag *t;
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if ((m->m_flags & M_PKTHDR) == 0)
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return NULL;
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n = m_aux_find(m, af, type);
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if (n)
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return n;
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MGET(n, M_DONTWAIT, m->m_type);
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if (n == NULL)
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return NULL;
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t = mtod(n, struct mauxtag *);
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bzero(t, sizeof(*t));
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t->af = af;
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t->type = type;
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t->p = p;
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n->m_data += sizeof(struct mauxtag);
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n->m_len = 0;
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n->m_next = m->m_pkthdr.aux;
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m->m_pkthdr.aux = n;
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return n;
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}
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struct mbuf *
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m_aux_find2(struct mbuf *m, int af, int type, void *p)
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{
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struct mbuf *n;
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struct mauxtag *t;
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if ((m->m_flags & M_PKTHDR) == 0)
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return NULL;
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for (n = m->m_pkthdr.aux; n; n = n->m_next) {
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t = (struct mauxtag *)n->m_dat;
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if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) {
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printf("m_aux_find: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data);
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continue;
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}
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if (t->af == af && t->type == type && t->p == p)
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return n;
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}
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return NULL;
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}
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struct mbuf *
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m_aux_find(struct mbuf *m, int af, int type)
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{
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return m_aux_find2(m, af, type, NULL);
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}
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struct mbuf *
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m_aux_add(struct mbuf *m, int af, int type)
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{
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return m_aux_add2(m, af, type, NULL);
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}
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void
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m_aux_delete(struct mbuf *m, struct mbuf *victim)
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{
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struct mbuf *n, *prev, *next;
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struct mauxtag *t;
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if ((m->m_flags & M_PKTHDR) == 0)
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return;
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prev = NULL;
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n = m->m_pkthdr.aux;
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while (n) {
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t = (struct mauxtag *)n->m_dat;
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next = n->m_next;
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if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) {
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printf("m_aux_delete: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data);
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prev = n;
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n = next;
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continue;
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}
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if (n == victim) {
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if (prev)
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prev->m_next = n->m_next;
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else
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m->m_pkthdr.aux = n->m_next;
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n->m_next = NULL;
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m_free(n);
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return;
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} else
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prev = n;
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n = next;
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}
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}
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