228 lines
5.6 KiB
C
228 lines
5.6 KiB
C
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/* $NetBSD: npf_mbuf.c,v 1.1 2010/08/22 18:56:22 rmind Exp $ */
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/*-
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* Copyright (c) 2009-2010 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This material is based upon work partially supported by The
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* NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* NPF network buffer management interface.
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*
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* Network buffer in NetBSD is mbuf. Internal mbuf structures are
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* abstracted within this source.
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*/
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#ifdef _KERNEL
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: npf_mbuf.c,v 1.1 2010/08/22 18:56:22 rmind Exp $");
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#endif
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#include <sys/param.h>
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#include <sys/mbuf.h>
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#include "npf_impl.h"
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/*
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* nbuf_dataptr: return a pointer to data in nbuf.
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*/
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void *
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nbuf_dataptr(nbuf_t *nbuf)
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{
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const struct mbuf *m = nbuf;
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return mtod(m, void *);
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}
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/*
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* nbuf_advance: advance in mbuf or chain by specified amount of bytes.
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*
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* => Returns new pointer to data in mbuf and NULL if offset gets invalid.
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* => Sets nbuf to current (after advance) mbuf in the chain.
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*/
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void *
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nbuf_advance(nbuf_t **nbuf, void *n_ptr, u_int n)
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{
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struct mbuf *m = *nbuf;
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u_int off, wmark;
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uint8_t *d;
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/* Offset with amount to advance. */
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off = (uintptr_t)n_ptr - mtod(m, uintptr_t) + n;
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wmark = m->m_len;
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/* Find the mbuf according to offset. */
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while (__predict_false(wmark <= off)) {
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m = m->m_next;
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if (__predict_false(m == NULL)) {
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/*
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* If out of chain, then offset is
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* higher than packet length.
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*/
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return NULL;
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}
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wmark += m->m_len;
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}
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/* Offset in mbuf data. */
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d = mtod(m, uint8_t *);
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KASSERT(off >= (wmark - m->m_len));
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d += (off - (wmark - m->m_len));
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*nbuf = (void *)m;
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return d;
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}
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/*
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* nbuf_rw_datum: read or write a datum of specified length at current
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* offset in the nbuf chain and copy datum into passed buffer.
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*
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* => Datum is allowed to overlap between two or more mbufs.
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* => Note: all data in nbuf is in network byte order.
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* => Returns 0 on success, error code on failure.
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*
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* Note: this function must be static inline with constant operation
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* parameter - we expect constant propagation.
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*/
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#define NBUF_DATA_READ 0
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#define NBUF_DATA_WRITE 1
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static inline int
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nbuf_rw_datum(const int wr, nbuf_t *nbuf, void *n_ptr, size_t len, void *buf)
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{
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uint8_t *d = n_ptr, *b = buf;
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struct mbuf *m = nbuf;
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u_int off, wmark, end;
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/* Current offset in mbuf. */
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off = (uintptr_t)n_ptr - mtod(m, uintptr_t);
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KASSERT(off < m->m_len);
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wmark = m->m_len;
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/* Is datum overlapping? */
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end = off + len;
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while (__predict_false(end > wmark)) {
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u_int l;
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/* Get the part of current mbuf. */
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l = m->m_len - off;
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KASSERT(l < len);
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len -= l;
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if (wr) {
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while (l--)
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*d++ = *b++;
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} else {
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while (l--)
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*b++ = *d++;
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}
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KASSERT(len > 0);
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/* Take next mbuf and continue. */
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m = m->m_next;
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if (__predict_false(m == NULL)) {
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/*
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* If out of chain, then offset with datum
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* length exceed the packet length.
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*/
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return EINVAL;
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}
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wmark += m->m_len;
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d = mtod(m, uint8_t *);
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off = 0;
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}
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KASSERT(n_ptr == d || mtod(m, uint8_t *) == d);
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KASSERT(len <= m->m_len);
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/* Non-overlapping case: fetch the actual data. */
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if (wr) {
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while (len--)
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*d++ = *b++;
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} else {
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while (len--)
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*b++ = *d++;
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}
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return 0;
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}
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/*
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* nbuf_{fetch|store}_datum: read/write absraction calls on nbuf_rw_datum().
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*/
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int
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nbuf_fetch_datum(nbuf_t *nbuf, void *n_ptr, size_t len, void *buf)
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{
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return nbuf_rw_datum(NBUF_DATA_READ, nbuf, n_ptr, len, buf);
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}
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int
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nbuf_store_datum(nbuf_t *nbuf, void *n_ptr, size_t len, void *buf)
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{
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return nbuf_rw_datum(NBUF_DATA_WRITE, nbuf, n_ptr, len, buf);
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}
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/*
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* nbuf_add_tag: add a tag to specified network buffer.
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*
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* => Returns 0 on success, or errno on failure.
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*/
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int
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nbuf_add_tag(nbuf_t *nbuf, uint32_t key, uint32_t val)
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{
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struct mbuf *m = nbuf;
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struct m_tag *mt;
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uint32_t *dat;
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mt = m_tag_get(PACKET_TAG_NPF, sizeof(uint32_t), M_NOWAIT);
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if (__predict_false(mt == NULL)) {
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return ENOMEM;
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}
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dat = (uint32_t *)(mt + 1);
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*dat = val;
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m_tag_prepend(m, mt);
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return 0;
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}
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/*
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* nbuf_find_tag: find a tag in specified network buffer.
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*
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* => Returns 0 on success, or errno on failure.
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*/
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int
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nbuf_find_tag(nbuf_t *nbuf, uint32_t key, void **data)
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{
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struct mbuf *m = nbuf;
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struct m_tag *mt;
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mt = m_tag_find(m, PACKET_TAG_NPF, NULL);
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if (__predict_false(mt == NULL)) {
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return EINVAL;
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}
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*data = (void *)(mt + 1);
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return 0;
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}
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