diff options
Diffstat (limited to 'sys/kern/uipc_mbuf2.c')
| -rw-r--r-- | sys/kern/uipc_mbuf2.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/sys/kern/uipc_mbuf2.c b/sys/kern/uipc_mbuf2.c new file mode 100644 index 0000000..37ee53e --- /dev/null +++ b/sys/kern/uipc_mbuf2.c @@ -0,0 +1,404 @@ +/* $FreeBSD$ */ +/* $KAME: uipc_mbuf2.c,v 1.31 2001/11/28 11:08:53 itojun Exp $ */ +/* $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $ */ + +/* + * Copyright (C) 1999 WIDE Project. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the project nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* + * Copyright (c) 1982, 1986, 1988, 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95 + */ + +/*#define PULLDOWN_DEBUG*/ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/lock.h> +#include <sys/malloc.h> +#include <sys/mbuf.h> +#include <sys/mutex.h> + +/* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ +static struct mbuf *m_dup1(struct mbuf *, int, int, int); + +/* + * ensure that [off, off + len) is contiguous on the mbuf chain "m". + * packet chain before "off" is kept untouched. + * if offp == NULL, the target will start at <retval, 0> on resulting chain. + * if offp != NULL, the target will start at <retval, *offp> on resulting chain. + * + * on error return (NULL return value), original "m" will be freed. + * + * XXX: M_TRAILINGSPACE/M_LEADINGSPACE only permitted on writable ext_buf. + */ +struct mbuf * +m_pulldown(struct mbuf *m, int off, int len, int *offp) +{ + struct mbuf *n, *o; + int hlen, tlen, olen; + int writable; + + /* check invalid arguments. */ + if (m == NULL) + panic("m == NULL in m_pulldown()"); + if (len > MCLBYTES) { + m_freem(m); + return NULL; /* impossible */ + } + +#ifdef PULLDOWN_DEBUG + { + struct mbuf *t; + printf("before:"); + for (t = m; t; t = t->m_next) + printf(" %d", t->m_len); + printf("\n"); + } +#endif + n = m; + while (n != NULL && off > 0) { + if (n->m_len > off) + break; + off -= n->m_len; + n = n->m_next; + } + /* be sure to point non-empty mbuf */ + while (n != NULL && n->m_len == 0) + n = n->m_next; + if (!n) { + m_freem(m); + return NULL; /* mbuf chain too short */ + } + + /* + * XXX: This code is flawed because it considers a "writable" mbuf + * data region to require all of the following: + * (i) mbuf _has_ to have M_EXT set; if it is just a regular + * mbuf, it is still not considered "writable." + * (ii) since mbuf has M_EXT, the ext_type _has_ to be + * EXT_CLUSTER. Anything else makes it non-writable. + * (iii) M_WRITABLE() must evaluate true. + * Ideally, the requirement should only be (iii). + * + * If we're writable, we're sure we're writable, because the ref. count + * cannot increase from 1, as that would require posession of mbuf + * n by someone else (which is impossible). However, if we're _not_ + * writable, we may eventually become writable )if the ref. count drops + * to 1), but we'll fail to notice it unless we re-evaluate + * M_WRITABLE(). For now, we only evaluate once at the beginning and + * live with this. + */ + /* + * XXX: This is dumb. If we're just a regular mbuf with no M_EXT, + * then we're not "writable," according to this code. + */ + writable = 0; + if ((n->m_flags & M_EXT) == 0 || + (n->m_ext.ext_type == EXT_CLUSTER && M_WRITABLE(n))) + writable = 1; + + /* + * the target data is on <n, off>. + * if we got enough data on the mbuf "n", we're done. + */ + if ((off == 0 || offp) && len <= n->m_len - off && writable) + goto ok; + + /* + * when len <= n->m_len - off and off != 0, it is a special case. + * len bytes from <n, off> sits in single mbuf, but the caller does + * not like the starting position (off). + * chop the current mbuf into two pieces, set off to 0. + */ + if (len <= n->m_len - off) { + o = m_dup1(n, off, n->m_len - off, M_DONTWAIT); + if (o == NULL) { + m_freem(m); + return NULL; /* ENOBUFS */ + } + n->m_len = off; + o->m_next = n->m_next; + n->m_next = o; + n = n->m_next; + off = 0; + goto ok; + } + + /* + * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, + * and construct contiguous mbuf with m_len == len. + * note that hlen + tlen == len, and tlen > 0. + */ + hlen = n->m_len - off; + tlen = len - hlen; + + /* + * ensure that we have enough trailing data on mbuf chain. + * if not, we can do nothing about the chain. + */ + olen = 0; + for (o = n->m_next; o != NULL; o = o->m_next) + olen += o->m_len; + if (hlen + olen < len) { + m_freem(m); + return NULL; /* mbuf chain too short */ + } + + /* + * easy cases first. + * we need to use m_copydata() to get data from <n->m_next, 0>. + */ + if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen + && writable) { + m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); + n->m_len += tlen; + m_adj(n->m_next, tlen); + goto ok; + } + if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen + && writable) { + n->m_next->m_data -= hlen; + n->m_next->m_len += hlen; + bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen); + n->m_len -= hlen; + n = n->m_next; + off = 0; + goto ok; + } + + /* + * now, we need to do the hard way. don't m_copy as there's no room + * on both end. + */ + MGET(o, M_DONTWAIT, m->m_type); + if (o && len > MLEN) { + MCLGET(o, M_DONTWAIT); + if ((o->m_flags & M_EXT) == 0) { + m_free(o); + o = NULL; + } + } + if (!o) { + m_freem(m); + return NULL; /* ENOBUFS */ + } + /* get hlen from <n, off> into <o, 0> */ + o->m_len = hlen; + bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); + n->m_len -= hlen; + /* get tlen from <n->m_next, 0> into <o, hlen> */ + m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); + o->m_len += tlen; + m_adj(n->m_next, tlen); + o->m_next = n->m_next; + n->m_next = o; + n = o; + off = 0; + +ok: +#ifdef PULLDOWN_DEBUG + { + struct mbuf *t; + printf("after:"); + for (t = m; t; t = t->m_next) + printf("%c%d", t == n ? '*' : ' ', t->m_len); + printf(" (off=%d)\n", off); + } +#endif + if (offp) + *offp = off; + return n; +} + +static struct mbuf * +m_dup1(struct mbuf *m, int off, int len, int wait) +{ + struct mbuf *n; + int l; + int copyhdr; + + if (len > MCLBYTES) + return NULL; + if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { + copyhdr = 1; + MGETHDR(n, wait, m->m_type); + l = MHLEN; + } else { + copyhdr = 0; + MGET(n, wait, m->m_type); + l = MLEN; + } + if (n && len > l) { + MCLGET(n, wait); + if ((n->m_flags & M_EXT) == 0) { + m_free(n); + n = NULL; + } + } + if (!n) + return NULL; + + if (copyhdr) + M_COPY_PKTHDR(n, m); + m_copydata(m, off, len, mtod(n, caddr_t)); + return n; +} + +/* + * pkthdr.aux chain manipulation. + * we don't allow clusters at this moment. + */ +struct mbuf * +m_aux_add2(struct mbuf *m, int af, int type, void *p) +{ + struct mbuf *n; + struct mauxtag *t; + + if ((m->m_flags & M_PKTHDR) == 0) + return NULL; + + n = m_aux_find(m, af, type); + if (n) + return n; + + MGET(n, M_DONTWAIT, m->m_type); + if (n == NULL) + return NULL; + + t = mtod(n, struct mauxtag *); + bzero(t, sizeof(*t)); + t->af = af; + t->type = type; + t->p = p; + n->m_data += sizeof(struct mauxtag); + n->m_len = 0; + n->m_next = m->m_pkthdr.aux; + m->m_pkthdr.aux = n; + return n; +} + +struct mbuf * +m_aux_find2(struct mbuf *m, int af, int type, void *p) +{ + struct mbuf *n; + struct mauxtag *t; + + if ((m->m_flags & M_PKTHDR) == 0) + return NULL; + + for (n = m->m_pkthdr.aux; n; n = n->m_next) { + t = (struct mauxtag *)n->m_dat; + if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) { + printf("m_aux_find: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data); + continue; + } + if (t->af == af && t->type == type && t->p == p) + return n; + } + return NULL; +} + +struct mbuf * +m_aux_find(struct mbuf *m, int af, int type) +{ + + return m_aux_find2(m, af, type, NULL); +} + +struct mbuf * +m_aux_add(struct mbuf *m, int af, int type) +{ + + return m_aux_add2(m, af, type, NULL); +} + +void +m_aux_delete(struct mbuf *m, struct mbuf *victim) +{ + struct mbuf *n, *prev, *next; + struct mauxtag *t; + + if ((m->m_flags & M_PKTHDR) == 0) + return; + + prev = NULL; + n = m->m_pkthdr.aux; + while (n) { + t = (struct mauxtag *)n->m_dat; + next = n->m_next; + if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) { + printf("m_aux_delete: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data); + prev = n; + n = next; + continue; + } + if (n == victim) { + if (prev) + prev->m_next = n->m_next; + else + m->m_pkthdr.aux = n->m_next; + n->m_next = NULL; + m_free(n); + return; + } else + prev = n; + n = next; + } +} |
