390 lines
10 KiB
C
390 lines
10 KiB
C
/* $OpenBSD: uipc_mbuf2.c,v 1.45 2020/12/12 11:48:54 jan Exp $ */
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/* $KAME: uipc_mbuf2.c,v 1.29 2001/02/14 13:42:10 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. 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/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/pool.h>
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#include <sys/mbuf.h>
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extern struct pool mtagpool;
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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 on shared cluster (sharedcluster)
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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 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 ((n = m_getptr(m, off, &off)) == NULL) {
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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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struct mbuf *mlast;
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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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for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next)
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;
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n->m_len = off;
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mlast->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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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 && n->m_next->m_len >= tlen) {
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n->m_next->m_data -= hlen;
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n->m_next->m_len += hlen;
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memmove(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_copym as there's no room
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* on both ends.
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*/
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if (len > MAXMCLBYTES) {
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m_freem(m);
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return (NULL);
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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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MCLGETL(o, M_DONTWAIT, len);
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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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memmove(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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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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if (len > MAXMCLBYTES)
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return (NULL);
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if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {
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MGETHDR(n, wait, m->m_type);
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if (n == NULL)
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return (NULL);
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if (m_dup_pkthdr(n, m, wait)) {
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m_free(n);
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return (NULL);
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}
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l = MHLEN;
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} else {
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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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MCLGETL(n, wait, len);
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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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m_copydata(m, off, len, mtod(n, caddr_t));
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n->m_len = len;
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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(int type, int len, 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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if (len > PACKET_TAG_MAXSIZE)
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panic("requested tag size for pool %#x is too big", type);
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t = pool_get(&mtagpool, wait == M_WAITOK ? PR_WAITOK : PR_NOWAIT);
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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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/* Prepend a packet tag. */
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void
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m_tag_prepend(struct mbuf *m, struct m_tag *t)
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{
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SLIST_INSERT_HEAD(&m->m_pkthdr.ph_tags, t, m_tag_link);
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m->m_pkthdr.ph_tagsset |= t->m_tag_id;
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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(struct mbuf *m, struct m_tag *t)
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{
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u_int32_t ph_tagsset = 0;
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struct m_tag *p;
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SLIST_REMOVE(&m->m_pkthdr.ph_tags, t, m_tag, m_tag_link);
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pool_put(&mtagpool, t);
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SLIST_FOREACH(p, &m->m_pkthdr.ph_tags, m_tag_link)
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ph_tagsset |= p->m_tag_id;
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m->m_pkthdr.ph_tagsset = ph_tagsset;
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}
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/* Unlink and free a packet tag chain. */
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void
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m_tag_delete_chain(struct mbuf *m)
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{
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struct m_tag *p;
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while ((p = SLIST_FIRST(&m->m_pkthdr.ph_tags)) != NULL) {
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SLIST_REMOVE_HEAD(&m->m_pkthdr.ph_tags, m_tag_link);
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pool_put(&mtagpool, p);
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}
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m->m_pkthdr.ph_tagsset = 0;
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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(struct mbuf *m, int type, struct m_tag *t)
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{
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struct m_tag *p;
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if (!(m->m_pkthdr.ph_tagsset & type))
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return (NULL);
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if (t == NULL)
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p = SLIST_FIRST(&m->m_pkthdr.ph_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(struct m_tag *t, int wait)
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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, wait);
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if (p == NULL)
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return (NULL);
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memcpy(p + 1, t + 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(struct mbuf *to, struct mbuf *from, int wait)
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{
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struct m_tag *p, *t, *tprev = NULL;
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m_tag_delete_chain(to);
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SLIST_FOREACH(p, &from->m_pkthdr.ph_tags, m_tag_link) {
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t = m_tag_copy(p, wait);
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if (t == NULL) {
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m_tag_delete_chain(to);
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return (ENOBUFS);
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}
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if (tprev == NULL)
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SLIST_INSERT_HEAD(&to->m_pkthdr.ph_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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to->m_pkthdr.ph_tagsset |= t->m_tag_id;
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}
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return (0);
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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(struct mbuf *m)
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{
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SLIST_INIT(&m->m_pkthdr.ph_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(struct mbuf *m)
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{
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return (SLIST_FIRST(&m->m_pkthdr.ph_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(struct mbuf *m, 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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