| /* $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. |
| * 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 |
| */ |
| |
| #include <sys/bsd_cdefs.h> |
| //__FBSDID("$FreeBSD$"); |
| |
| /*#define PULLDOWN_DEBUG*/ |
| |
| #include <sys/bsd_param.h> |
| #include <sys/bsd_systm.h> |
| #include <sys/bsd_kernel.h> |
| #include <sys/bsd_lock.h> |
| #include <sys/bsd_malloc.h> |
| #include <sys/bsd_mbuf.h> |
| #include <sys/bsd_mutex.h> |
| |
| //#include <security/mac/bsd_mac_framework.h> |
| |
| static MALLOC_DEFINE(M_PACKET_TAGS, MBUF_TAG_MEM_NAME, |
| "packet-attached information"); |
| |
| /* 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; |
| |
| CHECK_ADD_LINKCNT(n, o, n->m_next, "m_pulldown"); |
| 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. |
| */ |
| if (len > MLEN) |
| o = m_getcl(M_DONTWAIT, m->m_type, 0); |
| else |
| o = m_get(M_DONTWAIT, m->m_type); |
| 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); |
| |
| CHECK_ADD_LINKCNT(n, o, n->m_next, "m_pulldown"); |
| 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 copyhdr; |
| |
| if (len > MCLBYTES) |
| return NULL; |
| if (off == 0 && (m->m_flags & M_PKTHDR) != 0) |
| copyhdr = 1; |
| else |
| copyhdr = 0; |
| if (len >= MINCLSIZE) { |
| if (copyhdr == 1) |
| n = m_getcl(wait, m->m_type, M_PKTHDR); |
| else |
| n = m_getcl(wait, m->m_type, 0); |
| } else { |
| if (copyhdr == 1) |
| n = m_gethdr(wait, m->m_type); |
| else |
| n = m_get(wait, m->m_type); |
| } |
| if (!n) |
| return NULL; /* ENOBUFS */ |
| |
| if (copyhdr && !m_dup_pkthdr(n, m, wait)) { |
| m_free(n); |
| return NULL; |
| } |
| m_copydata(m, off, len, mtod(n, caddr_t)); |
| n->m_len = len; |
| return n; |
| } |
| |
| /* Free a packet tag. */ |
| void |
| m_tag_free_default(struct m_tag *t) |
| { |
| #ifdef MAC |
| if (t->m_tag_id == PACKET_TAG_MACLABEL) |
| mac_mbuf_tag_destroy(t); |
| #endif |
| bsd_free(t, M_PACKET_TAGS); |
| } |
| |
| /* Get a packet tag structure along with specified data following. */ |
| struct m_tag * |
| m_tag_alloc(u_int32_t cookie, int type, int len, int wait) |
| { |
| struct m_tag *t; |
| |
| MBUF_CHECKSLEEP(wait); |
| if (len < 0) |
| return NULL; |
| t = bsd_malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait); |
| if (t == NULL) |
| return NULL; |
| m_tag_setup(t, cookie, type, len); |
| t->m_tag_free = m_tag_free_default; |
| return t; |
| } |
| |
| /* Unlink and free a packet tag. */ |
| void |
| m_tag_delete(struct mbuf *m, struct m_tag *t) |
| { |
| |
| KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t)); |
| m_tag_unlink(m, t); |
| m_tag_free(t); |
| } |
| |
| /* Unlink and free a packet tag chain, starting from given tag. */ |
| void |
| m_tag_delete_chain(struct mbuf *m, struct m_tag *t) |
| { |
| struct m_tag *p, *q; |
| |
| KASSERT(m, ("m_tag_delete_chain: null mbuf")); |
| if (t != NULL) |
| p = t; |
| else |
| p = SLIST_FIRST(&m->m_pkthdr.tags); |
| if (p == NULL) |
| return; |
| while ((q = SLIST_NEXT(p, m_tag_link)) != NULL) |
| m_tag_delete(m, q); |
| m_tag_delete(m, p); |
| } |
| |
| /* |
| * Strip off all tags that would normally vanish when |
| * passing through a network interface. Only persistent |
| * tags will exist after this; these are expected to remain |
| * so long as the mbuf chain exists, regardless of the |
| * path the mbufs take. |
| */ |
| void |
| m_tag_delete_nonpersistent(struct mbuf *m) |
| { |
| struct m_tag *p, *q; |
| |
| SLIST_FOREACH_SAFE(p, &m->m_pkthdr.tags, m_tag_link, q) |
| if ((p->m_tag_id & MTAG_PERSISTENT) == 0) |
| m_tag_delete(m, p); |
| } |
| |
| /* Find a tag, starting from a given position. */ |
| struct m_tag * |
| m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t) |
| { |
| struct m_tag *p; |
| |
| KASSERT(m, ("m_tag_locate: null mbuf")); |
| if (t == NULL) |
| p = SLIST_FIRST(&m->m_pkthdr.tags); |
| else |
| p = SLIST_NEXT(t, m_tag_link); |
| while (p != NULL) { |
| if (p->m_tag_cookie == cookie && p->m_tag_id == type) |
| return p; |
| p = SLIST_NEXT(p, m_tag_link); |
| } |
| return NULL; |
| } |
| |
| /* Copy a single tag. */ |
| struct m_tag * |
| m_tag_copy(struct m_tag *t, int how) |
| { |
| struct m_tag *p; |
| |
| MBUF_CHECKSLEEP(how); |
| KASSERT(t, ("m_tag_copy: null tag")); |
| p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how); |
| if (p == NULL) |
| return (NULL); |
| #ifdef MAC |
| /* |
| * XXXMAC: we should probably pass off the initialization, and |
| * copying here? can we hide that PACKET_TAG_MACLABEL is |
| * special from the mbuf code? |
| */ |
| if (t->m_tag_id == PACKET_TAG_MACLABEL) { |
| if (mac_mbuf_tag_init(p, how) != 0) { |
| m_tag_free(p); |
| return (NULL); |
| } |
| mac_mbuf_tag_copy(t, p); |
| } else |
| #endif |
| bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */ |
| return p; |
| } |
| |
| /* |
| * Copy two tag chains. The destination mbuf (to) loses any attached |
| * tags even if the operation fails. This should not be a problem, as |
| * m_tag_copy_chain() is typically called with a newly-allocated |
| * destination mbuf. |
| */ |
| int |
| m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int how) |
| { |
| struct m_tag *p, *t, *tprev = NULL; |
| |
| MBUF_CHECKSLEEP(how); |
| KASSERT(to && from, |
| ("m_tag_copy_chain: null argument, to %p from %p", to, from)); |
| m_tag_delete_chain(to, NULL); |
| SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) { |
| t = m_tag_copy(p, how); |
| if (t == NULL) { |
| m_tag_delete_chain(to, NULL); |
| return 0; |
| } |
| if (tprev == NULL) |
| SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link); |
| else |
| SLIST_INSERT_AFTER(tprev, t, m_tag_link); |
| tprev = t; |
| } |
| return 1; |
| } |