395 lines
10 KiB
C
395 lines
10 KiB
C
/* $NetBSD: uipc_mbuf2.c,v 1.12 2003/01/17 08:11:52 itojun Exp $ */
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/* $KAME: uipc_mbuf2.c,v 1.29 2001/02/14 13:42:10 itojun 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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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: uipc_mbuf2.c,v 1.12 2003/01/17 08:11:52 itojun Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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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 on shared cluster (sharedcluster)
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*/
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struct mbuf *
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m_pulldown(m, off, len, offp)
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struct mbuf *m;
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int off, len;
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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 sharedcluster;
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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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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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sharedcluster = M_READONLY(n);
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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 && !sharedcluster)
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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_dup(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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!sharedcluster) {
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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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!sharedcluster) {
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n->m_next->m_data -= hlen;
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n->m_next->m_len += hlen;
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memcpy(mtod(n->m_next, caddr_t), mtod(n, caddr_t) + off, 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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memcpy(mtod(o, caddr_t), mtod(n, caddr_t) + off, 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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if (offp)
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*offp = off;
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return n;
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}
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/* Get a packet tag structure along with specified data following. */
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struct m_tag *
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m_tag_get(type, len, wait)
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int type;
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int len;
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int wait;
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{
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struct m_tag *t;
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if (len < 0)
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return (NULL);
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t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait);
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if (t == NULL)
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return (NULL);
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t->m_tag_id = type;
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t->m_tag_len = len;
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return (t);
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}
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/* Free a packet tag. */
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void
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m_tag_free(t)
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struct m_tag *t;
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{
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free(t, M_PACKET_TAGS);
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}
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/* Prepend a packet tag. */
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void
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m_tag_prepend(m, t)
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struct mbuf *m;
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struct m_tag *t;
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{
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SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
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}
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/* Unlink a packet tag. */
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void
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m_tag_unlink(m, t)
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struct mbuf *m;
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struct m_tag *t;
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{
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SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
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}
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/* Unlink and free a packet tag. */
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void
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m_tag_delete(m, t)
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struct mbuf *m;
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struct m_tag *t;
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{
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m_tag_unlink(m, t);
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m_tag_free(t);
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}
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/* Unlink and free a packet tag chain, starting from given tag. */
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void
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m_tag_delete_chain(m, t)
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struct mbuf *m;
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struct m_tag *t;
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{
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struct m_tag *p, *q;
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if (t != NULL)
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p = t;
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else
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p = SLIST_FIRST(&m->m_pkthdr.tags);
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if (p == NULL)
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return;
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while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
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m_tag_delete(m, q);
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m_tag_delete(m, p);
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}
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/* Find a tag, starting from a given position. */
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struct m_tag *
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m_tag_find(m, type, t)
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struct mbuf *m;
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int type;
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struct m_tag *t;
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{
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struct m_tag *p;
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if (t == NULL)
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p = SLIST_FIRST(&m->m_pkthdr.tags);
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else
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p = SLIST_NEXT(t, m_tag_link);
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while (p != NULL) {
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if (p->m_tag_id == type)
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return (p);
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p = SLIST_NEXT(p, m_tag_link);
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}
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return (NULL);
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}
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/* Copy a single tag. */
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struct m_tag *
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m_tag_copy(t)
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struct m_tag *t;
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{
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struct m_tag *p;
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p = m_tag_get(t->m_tag_id, t->m_tag_len, M_NOWAIT);
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if (p == NULL)
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return (NULL);
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bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */
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return (p);
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}
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/*
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* Copy two tag chains. The destination mbuf (to) loses any attached
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* tags even if the operation fails. This should not be a problem, as
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* m_tag_copy_chain() is typically called with a newly-allocated
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* destination mbuf.
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*/
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int
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m_tag_copy_chain(to, from)
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struct mbuf *to;
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struct mbuf *from;
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{
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struct m_tag *p, *t, *tprev = NULL;
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m_tag_delete_chain(to, NULL);
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SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
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t = m_tag_copy(p);
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if (t == NULL) {
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m_tag_delete_chain(to, NULL);
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return (0);
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}
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if (tprev == NULL)
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SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
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else
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SLIST_INSERT_AFTER(tprev, t, m_tag_link);
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tprev = t;
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}
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return (1);
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}
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/* Initialize tags on an mbuf. */
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void
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m_tag_init(m)
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struct mbuf *m;
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{
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SLIST_INIT(&m->m_pkthdr.tags);
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}
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/* Get first tag in chain. */
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struct m_tag *
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m_tag_first(m)
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struct mbuf *m;
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{
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return (SLIST_FIRST(&m->m_pkthdr.tags));
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}
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/* Get next tag in chain. */
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struct m_tag *
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m_tag_next(m, t)
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struct mbuf *m;
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struct m_tag *t;
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{
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return (SLIST_NEXT(t, m_tag_link));
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}
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