/* $NetBSD: uipc_mbuf.c,v 1.73 2003/09/07 12:04:13 yamt Exp $ */ /*- * Copyright (c) 1999, 2001 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, * NASA Ames Research Center. * * 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 NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. 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 __KERNEL_RCSID(0, "$NetBSD: uipc_mbuf.c,v 1.73 2003/09/07 12:04:13 yamt Exp $"); #include "opt_mbuftrace.h" #include #include #include #include #define MBTYPES #include #include #include #include #include #include #include #include #include #include struct pool mbpool; /* mbuf pool */ struct pool mclpool; /* mbuf cluster pool */ struct pool_cache mbpool_cache; struct pool_cache mclpool_cache; struct mbstat mbstat; int max_linkhdr; int max_protohdr; int max_hdr; int max_datalen; static int mb_ctor(void *, void *, int); void *mclpool_alloc(struct pool *, int); void mclpool_release(struct pool *, void *); struct pool_allocator mclpool_allocator = { mclpool_alloc, mclpool_release, 0, }; static struct mbuf *m_copym0 __P((struct mbuf *, int, int, int, int)); const char mclpool_warnmsg[] = "WARNING: mclpool limit reached; increase NMBCLUSTERS"; MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf"); #ifdef MBUFTRACE struct mownerhead mowners = LIST_HEAD_INITIALIZER(mowners); struct mowner unknown_mowners[] = { { "unknown", "free" }, { "unknown", "data" }, { "unknown", "header" }, { "unknown", "soname" }, { "unknown", "soopts" }, { "unknown", "ftable" }, { "unknown", "control" }, { "unknown", "oobdata" }, }; struct mowner revoked_mowner = { "revoked", "" }; #endif /* * Initialize the mbuf allocator. */ void mbinit(void) { KASSERT(sizeof(struct _m_ext) <= MHLEN); KASSERT(sizeof(struct mbuf) == MSIZE); pool_init(&mbpool, msize, 0, 0, 0, "mbpl", NULL); pool_init(&mclpool, mclbytes, 0, 0, 0, "mclpl", &mclpool_allocator); pool_set_drain_hook(&mbpool, m_reclaim, NULL); pool_set_drain_hook(&mclpool, m_reclaim, NULL); pool_cache_init(&mbpool_cache, &mbpool, mb_ctor, NULL, NULL); pool_cache_init(&mclpool_cache, &mclpool, NULL, NULL, NULL); /* * Set the hard limit on the mclpool to the number of * mbuf clusters the kernel is to support. Log the limit * reached message max once a minute. */ pool_sethardlimit(&mclpool, nmbclusters, mclpool_warnmsg, 60); /* * Set a low water mark for both mbufs and clusters. This should * help ensure that they can be allocated in a memory starvation * situation. This is important for e.g. diskless systems which * must allocate mbufs in order for the pagedaemon to clean pages. */ pool_setlowat(&mbpool, mblowat); pool_setlowat(&mclpool, mcllowat); #ifdef MBUFTRACE { /* * Attach the unknown mowners. */ int i; MOWNER_ATTACH(&revoked_mowner); for (i = sizeof(unknown_mowners)/sizeof(unknown_mowners[0]); i-- > 0; ) MOWNER_ATTACH(&unknown_mowners[i]); } #endif } int sysctl_dombuf(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen) { int error, newval; /* All sysctl names at this level are terminal. */ if (namelen != 1) return (ENOTDIR); /* overloaded */ switch (name[0]) { case MBUF_MSIZE: return (sysctl_rdint(oldp, oldlenp, newp, msize)); case MBUF_MCLBYTES: return (sysctl_rdint(oldp, oldlenp, newp, mclbytes)); case MBUF_NMBCLUSTERS: /* * If we have direct-mapped pool pages, we can adjust this * number on the fly. If not, we're limited by the size * of mb_map, and cannot change this value. * * Note: we only allow the value to be increased, never * decreased. */ if (mb_map == NULL) { newval = nmbclusters; error = sysctl_int(oldp, oldlenp, newp, newlen, &newval); if (error != 0) return (error); if (newp != NULL) { if (newval >= nmbclusters) { nmbclusters = newval; pool_sethardlimit(&mclpool, nmbclusters, mclpool_warnmsg, 60); } else error = EINVAL; } return (error); } else return (sysctl_rdint(oldp, oldlenp, newp, nmbclusters)); case MBUF_MBLOWAT: case MBUF_MCLLOWAT: /* New value must be >= 0. */ newval = (name[0] == MBUF_MBLOWAT) ? mblowat : mcllowat; error = sysctl_int(oldp, oldlenp, newp, newlen, &newval); if (error != 0) return (error); if (newp != NULL) { if (newval >= 0) { if (name[0] == MBUF_MBLOWAT) { mblowat = newval; pool_setlowat(&mbpool, newval); } else { mcllowat = newval; pool_setlowat(&mclpool, newval); } } else error = EINVAL; } return (error); case MBUF_STATS: return (sysctl_rdstruct(oldp, oldlenp, newp, &mbstat, sizeof(mbstat))); #ifdef MBUFTRACE case MBUF_MOWNERS: { struct mowner *mo; size_t len = 0; if (newp != NULL) return (EPERM); error = 0; LIST_FOREACH(mo, &mowners, mo_link) { if (oldp != NULL) { if (*oldlenp - len < sizeof(*mo)) { error = ENOMEM; break; } error = copyout(mo, (caddr_t) oldp + len, sizeof(*mo)); if (error) break; } len += sizeof(*mo); } *oldlenp = len; return (error); } #endif default: return (EOPNOTSUPP); } /* NOTREACHED */ } void * mclpool_alloc(struct pool *pp, int flags) { boolean_t waitok = (flags & PR_WAITOK) ? TRUE : FALSE; return ((void *)uvm_km_alloc_poolpage1(mb_map, NULL, waitok)); } void mclpool_release(struct pool *pp, void *v) { uvm_km_free_poolpage1(mb_map, (vaddr_t)v); } /*ARGSUSED*/ static int mb_ctor(void *arg, void *object, int flags) { struct mbuf *m = object; #ifdef POOL_VTOPHYS m->m_paddr = POOL_VTOPHYS(m); #else m->m_paddr = M_PADDR_INVALID; #endif return (0); } void m_reclaim(void *arg, int flags) { struct domain *dp; struct protosw *pr; struct ifnet *ifp; int s = splvm(); for (dp = domains; dp; dp = dp->dom_next) for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) if (pr->pr_drain) (*pr->pr_drain)(); for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list)) if (ifp->if_drain) (*ifp->if_drain)(ifp); splx(s); mbstat.m_drain++; } /* * Space allocation routines. * These are also available as macros * for critical paths. */ struct mbuf * m_get(int nowait, int type) { struct mbuf *m; MGET(m, nowait, type); return (m); } struct mbuf * m_gethdr(int nowait, int type) { struct mbuf *m; MGETHDR(m, nowait, type); return (m); } struct mbuf * m_getclr(int nowait, int type) { struct mbuf *m; MGET(m, nowait, type); if (m == 0) return (NULL); memset(mtod(m, caddr_t), 0, MLEN); return (m); } void m_clget(struct mbuf *m, int nowait) { MCLGET(m, nowait); } struct mbuf * m_free(struct mbuf *m) { struct mbuf *n; MFREE(m, n); return (n); } void m_freem(struct mbuf *m) { struct mbuf *n; if (m == NULL) return; do { MFREE(m, n); m = n; } while (m); } #ifdef MBUFTRACE void m_claim(struct mbuf *m, struct mowner *mo) { for (; m != NULL; m = m->m_next) MCLAIM(m, mo); } #endif /* * Mbuffer utility routines. */ /* * Lesser-used path for M_PREPEND: * allocate new mbuf to prepend to chain, * copy junk along. */ struct mbuf * m_prepend(struct mbuf *m, int len, int how) { struct mbuf *mn; MGET(mn, how, m->m_type); if (mn == (struct mbuf *)NULL) { m_freem(m); return ((struct mbuf *)NULL); } if (m->m_flags & M_PKTHDR) { M_COPY_PKTHDR(mn, m); m->m_flags &= ~M_PKTHDR; } else { MCLAIM(mn, m->m_owner); } mn->m_next = m; m = mn; if (len < MHLEN) MH_ALIGN(m, len); m->m_len = len; return (m); } /* * Make a copy of an mbuf chain starting "off0" bytes from the beginning, * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf. * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller. */ int MCFail; struct mbuf * m_copym(struct mbuf *m, int off0, int len, int wait) { return m_copym0(m, off0, len, wait, 0); /* shallow copy on M_EXT */ } struct mbuf * m_dup(struct mbuf *m, int off0, int len, int wait) { return m_copym0(m, off0, len, wait, 1); /* deep copy */ } static struct mbuf * m_copym0(struct mbuf *m, int off0, int len, int wait, int deep) { struct mbuf *n, **np; int off = off0; struct mbuf *top; int copyhdr = 0; if (off < 0 || len < 0) panic("m_copym: off %d, len %d", off, len); if (off == 0 && m->m_flags & M_PKTHDR) copyhdr = 1; while (off > 0) { if (m == 0) panic("m_copym: m == 0"); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } np = ⊤ top = 0; while (len > 0) { if (m == 0) { if (len != M_COPYALL) panic("m_copym: m == 0 and not COPYALL"); break; } MGET(n, wait, m->m_type); *np = n; if (n == 0) goto nospace; MCLAIM(n, m->m_owner); if (copyhdr) { M_COPY_PKTHDR(n, m); if (len == M_COPYALL) n->m_pkthdr.len -= off0; else n->m_pkthdr.len = len; copyhdr = 0; } n->m_len = min(len, m->m_len - off); if (m->m_flags & M_EXT) { if (!deep) { n->m_data = m->m_data + off; n->m_ext = m->m_ext; MCLADDREFERENCE(m, n); } else { /* * we are unsure about the way m was allocated. * copy into multiple MCLBYTES cluster mbufs. */ MCLGET(n, wait); n->m_len = 0; n->m_len = M_TRAILINGSPACE(n); n->m_len = min(n->m_len, len); n->m_len = min(n->m_len, m->m_len - off); memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, (unsigned)n->m_len); } } else memcpy(mtod(n, caddr_t), mtod(m, caddr_t)+off, (unsigned)n->m_len); if (len != M_COPYALL) len -= n->m_len; off += n->m_len; #ifdef DIAGNOSTIC if (off > m->m_len) panic("m_copym0 overrun"); #endif if (off == m->m_len) { m = m->m_next; off = 0; } np = &n->m_next; } if (top == 0) MCFail++; return (top); nospace: m_freem(top); MCFail++; return (NULL); } /* * Copy an entire packet, including header (which must be present). * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'. */ struct mbuf * m_copypacket(struct mbuf *m, int how) { struct mbuf *top, *n, *o; MGET(n, how, m->m_type); top = n; if (!n) goto nospace; MCLAIM(n, m->m_owner); M_COPY_PKTHDR(n, m); n->m_len = m->m_len; if (m->m_flags & M_EXT) { n->m_data = m->m_data; n->m_ext = m->m_ext; MCLADDREFERENCE(m, n); } else { memcpy(mtod(n, char *), mtod(m, char *), n->m_len); } m = m->m_next; while (m) { MGET(o, how, m->m_type); if (!o) goto nospace; MCLAIM(o, m->m_owner); n->m_next = o; n = n->m_next; n->m_len = m->m_len; if (m->m_flags & M_EXT) { n->m_data = m->m_data; n->m_ext = m->m_ext; MCLADDREFERENCE(m, n); } else { memcpy(mtod(n, char *), mtod(m, char *), n->m_len); } m = m->m_next; } return top; nospace: m_freem(top); MCFail++; return NULL; } /* * Copy data from an mbuf chain starting "off" bytes from the beginning, * continuing for "len" bytes, into the indicated buffer. */ void m_copydata(struct mbuf *m, int off, int len, caddr_t cp) { unsigned count; if (off < 0 || len < 0) panic("m_copydata"); while (off > 0) { if (m == 0) panic("m_copydata"); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { if (m == 0) panic("m_copydata"); count = min(m->m_len - off, len); memcpy(cp, mtod(m, caddr_t) + off, count); len -= count; cp += count; off = 0; m = m->m_next; } } /* * Concatenate mbuf chain n to m. * n might be copied into m (when n->m_len is small), therefore data portion of * n could be copied into an mbuf of different mbuf type. * Therefore both chains should be of the same type (e.g. MT_DATA). * Any m_pkthdr is not updated. */ void m_cat(struct mbuf *m, struct mbuf *n) { KASSERT(n == NULL || m->m_type == n->m_type); while (m->m_next) m = m->m_next; while (n) { if (m->m_flags & M_EXT || m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) { /* just join the two chains */ m->m_next = n; return; } /* splat the data from one into the other */ memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), (u_int)n->m_len); m->m_len += n->m_len; n = m_free(n); } } void m_adj(struct mbuf *mp, int req_len) { int len = req_len; struct mbuf *m; int count; if ((m = mp) == NULL) return; if (len >= 0) { /* * Trim from head. */ while (m != NULL && len > 0) { if (m->m_len <= len) { len -= m->m_len; m->m_len = 0; m = m->m_next; } else { m->m_len -= len; m->m_data += len; len = 0; } } m = mp; if (mp->m_flags & M_PKTHDR) m->m_pkthdr.len -= (req_len - len); } else { /* * Trim from tail. Scan the mbuf chain, * calculating its length and finding the last mbuf. * If the adjustment only affects this mbuf, then just * adjust and return. Otherwise, rescan and truncate * after the remaining size. */ len = -len; count = 0; for (;;) { count += m->m_len; if (m->m_next == (struct mbuf *)0) break; m = m->m_next; } if (m->m_len >= len) { m->m_len -= len; if (mp->m_flags & M_PKTHDR) mp->m_pkthdr.len -= len; return; } count -= len; if (count < 0) count = 0; /* * Correct length for chain is "count". * Find the mbuf with last data, adjust its length, * and toss data from remaining mbufs on chain. */ m = mp; if (m->m_flags & M_PKTHDR) m->m_pkthdr.len = count; for (; m; m = m->m_next) { if (m->m_len >= count) { m->m_len = count; break; } count -= m->m_len; } while (m->m_next) (m = m->m_next) ->m_len = 0; } } /* * Rearange an mbuf chain so that len bytes are contiguous * and in the data area of an mbuf (so that mtod and dtom * will work for a structure of size len). Returns the resulting * mbuf chain on success, frees it and returns null on failure. * If there is room, it will add up to max_protohdr-len extra bytes to the * contiguous region in an attempt to avoid being called next time. */ int MPFail; struct mbuf * m_pullup(struct mbuf *n, int len) { struct mbuf *m; int count; int space; /* * If first mbuf has no cluster, and has room for len bytes * without shifting current data, pullup into it, * otherwise allocate a new mbuf to prepend to the chain. */ if ((n->m_flags & M_EXT) == 0 && n->m_data + len < &n->m_dat[MLEN] && n->m_next) { if (n->m_len >= len) return (n); m = n; n = n->m_next; len -= m->m_len; } else { if (len > MHLEN) goto bad; MGET(m, M_DONTWAIT, n->m_type); if (m == 0) goto bad; MCLAIM(m, n->m_owner); m->m_len = 0; if (n->m_flags & M_PKTHDR) { M_COPY_PKTHDR(m, n); n->m_flags &= ~M_PKTHDR; } } space = &m->m_dat[MLEN] - (m->m_data + m->m_len); do { count = min(min(max(len, max_protohdr), space), n->m_len); memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), (unsigned)count); len -= count; m->m_len += count; n->m_len -= count; space -= count; if (n->m_len) n->m_data += count; else n = m_free(n); } while (len > 0 && n); if (len > 0) { (void) m_free(m); goto bad; } m->m_next = n; return (m); bad: m_freem(n); MPFail++; return (NULL); } /* * Like m_pullup(), except a new mbuf is always allocated, and we allow * the amount of empty space before the data in the new mbuf to be specified * (in the event that the caller expects to prepend later). */ int MSFail; struct mbuf * m_copyup(struct mbuf *n, int len, int dstoff) { struct mbuf *m; int count, space; if (len > (MHLEN - dstoff)) goto bad; MGET(m, M_DONTWAIT, n->m_type); if (m == NULL) goto bad; MCLAIM(m, n->m_owner); m->m_len = 0; if (n->m_flags & M_PKTHDR) { M_COPY_PKTHDR(m, n); n->m_flags &= ~M_PKTHDR; } m->m_data += dstoff; space = &m->m_dat[MLEN] - (m->m_data + m->m_len); do { count = min(min(max(len, max_protohdr), space), n->m_len); memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t), (unsigned)count); len -= count; m->m_len += count; n->m_len -= count; space -= count; if (n->m_len) n->m_data += count; else n = m_free(n); } while (len > 0 && n); if (len > 0) { (void) m_free(m); goto bad; } m->m_next = n; return (m); bad: m_freem(n); MSFail++; return (NULL); } /* * Partition an mbuf chain in two pieces, returning the tail -- * all but the first len0 bytes. In case of failure, it returns NULL and * attempts to restore the chain to its original state. */ struct mbuf * m_split(struct mbuf *m0, int len0, int wait) { struct mbuf *m, *n; unsigned len = len0, remain, len_save; for (m = m0; m && len > m->m_len; m = m->m_next) len -= m->m_len; if (m == 0) return (NULL); remain = m->m_len - len; if (m0->m_flags & M_PKTHDR) { MGETHDR(n, wait, m0->m_type); if (n == 0) return (NULL); MCLAIM(m, m0->m_owner); n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; n->m_pkthdr.len = m0->m_pkthdr.len - len0; len_save = m0->m_pkthdr.len; m0->m_pkthdr.len = len0; if (m->m_flags & M_EXT) goto extpacket; if (remain > MHLEN) { /* m can't be the lead packet */ MH_ALIGN(n, 0); n->m_next = m_split(m, len, wait); if (n->m_next == 0) { (void) m_free(n); m0->m_pkthdr.len = len_save; return (NULL); } else return (n); } else MH_ALIGN(n, remain); } else if (remain == 0) { n = m->m_next; m->m_next = 0; return (n); } else { MGET(n, wait, m->m_type); if (n == 0) return (NULL); MCLAIM(n, m->m_owner); M_ALIGN(n, remain); } extpacket: if (m->m_flags & M_EXT) { n->m_ext = m->m_ext; MCLADDREFERENCE(m, n); n->m_data = m->m_data + len; } else { memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + len, remain); } n->m_len = remain; m->m_len = len; n->m_next = m->m_next; m->m_next = 0; return (n); } /* * Routine to copy from device local memory into mbufs. */ struct mbuf * m_devget(char *buf, int totlen, int off0, struct ifnet *ifp, void (*copy)(const void *from, void *to, size_t len)) { struct mbuf *m; struct mbuf *top = 0, **mp = ⊤ int off = off0, len; char *cp; char *epkt; cp = buf; epkt = cp + totlen; if (off) { /* * If 'off' is non-zero, packet is trailer-encapsulated, * so we have to skip the type and length fields. */ cp += off + 2 * sizeof(u_int16_t); totlen -= 2 * sizeof(u_int16_t); } MGETHDR(m, M_DONTWAIT, MT_DATA); if (m == 0) return (NULL); m->m_pkthdr.rcvif = ifp; m->m_pkthdr.len = totlen; m->m_len = MHLEN; while (totlen > 0) { if (top) { MGET(m, M_DONTWAIT, MT_DATA); if (m == 0) { m_freem(top); return (NULL); } m->m_len = MLEN; } len = min(totlen, epkt - cp); if (len >= MINCLSIZE) { MCLGET(m, M_DONTWAIT); if ((m->m_flags & M_EXT) == 0) { m_free(m); m_freem(top); return (NULL); } m->m_len = len = min(len, MCLBYTES); } else { /* * Place initial small packet/header at end of mbuf. */ if (len < m->m_len) { if (top == 0 && len + max_linkhdr <= m->m_len) m->m_data += max_linkhdr; m->m_len = len; } else len = m->m_len; } if (copy) copy(cp, mtod(m, caddr_t), (size_t)len); else memcpy(mtod(m, caddr_t), cp, (size_t)len); cp += len; *mp = m; mp = &m->m_next; totlen -= len; if (cp == epkt) cp = buf; } return (top); } /* * Copy data from a buffer back into the indicated mbuf chain, * starting "off" bytes from the beginning, extending the mbuf * chain if necessary. */ void m_copyback(struct mbuf *m0, int off, int len, caddr_t cp) { int mlen; struct mbuf *m = m0, *n; int totlen = 0; if (m0 == 0) return; while (off > (mlen = m->m_len)) { off -= mlen; totlen += mlen; if (m->m_next == 0) { n = m_getclr(M_DONTWAIT, m->m_type); if (n == 0) goto out; n->m_len = min(MLEN, len + off); m->m_next = n; } m = m->m_next; } while (len > 0) { mlen = min (m->m_len - off, len); memcpy(mtod(m, caddr_t) + off, cp, (unsigned)mlen); cp += mlen; len -= mlen; mlen += off; off = 0; totlen += mlen; if (len == 0) break; if (m->m_next == 0) { n = m_get(M_DONTWAIT, m->m_type); if (n == 0) break; n->m_len = min(MLEN, len); m->m_next = n; } m = m->m_next; } out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) m->m_pkthdr.len = totlen; } /* * Apply function f to the data in an mbuf chain starting "off" bytes from the * beginning, continuing for "len" bytes. */ int m_apply(struct mbuf *m, int off, int len, int (*f)(void *, caddr_t, unsigned int), void *arg) { unsigned int count; int rval; KASSERT(len >= 0); KASSERT(off >= 0); while (off > 0) { KASSERT(m != NULL); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { KASSERT(m != NULL); count = min(m->m_len - off, len); rval = (*f)(arg, mtod(m, caddr_t) + off, count); if (rval) return (rval); len -= count; off = 0; m = m->m_next; } return (0); } /* * Return a pointer to mbuf/offset of location in mbuf chain. */ struct mbuf * m_getptr(struct mbuf *m, int loc, int *off) { while (loc >= 0) { /* Normal end of search */ if (m->m_len > loc) { *off = loc; return (m); } else { loc -= m->m_len; if (m->m_next == NULL) { if (loc == 0) { /* Point at the end of valid data */ *off = m->m_len; return (m); } else return (NULL); } else m = m->m_next; } } return (NULL); }