/* $FreeBSD$ */ /* $KAME: uipc_mbuf2.c,v 1.15 2000/02/22 14:01:37 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 #include #include #include #include /* * 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 on resulting chain. * if offp != NULL, the target will start at on resulting chain. * * on error return (NULL return value), original "m" will be freed. * * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster) */ struct mbuf * m_pulldown(m, off, len, offp) struct mbuf *m; int off, len; int *offp; { struct mbuf *n, *o; int hlen, tlen, olen; int sharedcluster; /* 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 */ } /* * the target data is on . * if we got enough data on the mbuf "n", we're done. */ if ((off == 0 || offp) && len <= n->m_len - off) goto ok; /* * when len < n->m_len - off and off != 0, it is a special case. * len bytes from 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_copym(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 and tlen from 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 m_next, 0>. */ if ((n->m_flags & M_EXT) == 0) sharedcluster = 0; else { if (n->m_ext.ext_free) sharedcluster = 1; else if (mclrefcnt[mtocl(n->m_ext.ext_buf)] > 1) sharedcluster = 1; else sharedcluster = 0; } if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen && !sharedcluster) { 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 && !sharedcluster) { 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 == NULL) { m_freem(m); return NULL; /* ENOBUFS */ } if (len > MHLEN) { /* use MHLEN just for safety */ MCLGET(o, M_DONTWAIT); if ((o->m_flags & M_EXT) == 0) { m_freem(m); m_free(o); return NULL; /* ENOBUFS */ } } /* get hlen from into */ o->m_len = hlen; bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen); n->m_len -= hlen; /* get tlen from m_next, 0> into */ 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; } /* * pkthdr.aux chain manipulation. * we don't allow clusters at this moment. */ struct mbuf * m_aux_add(m, af, type) struct mbuf *m; int af, type; { 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 *); t->af = af; t->type = type; 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_find(m, af, type) struct mbuf *m; int af, type; { 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 (t->af == af && t->type == type) return n; } return NULL; } void m_aux_delete(m, victim) 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 == victim) { if (prev) prev->m_next = n->m_next; else m->m_pkthdr.aux = n->m_next; n->m_next = NULL; m_free(n); } else prev = n; n = next; } }