/* $OpenBSD: uipc_mbuf.c,v 1.84 2007/06/02 09:45:32 art Exp $ */ /* $NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $ */ /* * 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 8.2 (Berkeley) 1/4/94 */ /* * @(#)COPYRIGHT 1.1 (NRL) 17 January 1995 * * NRL grants permission for redistribution and use in source and binary * forms, with or without modification, of the software and documentation * created at NRL 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 acknowledgements: * This product includes software developed by the University of * California, Berkeley and its contributors. * This product includes software developed at the Information * Technology Division, US Naval Research Laboratory. * 4. Neither the name of the NRL nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL 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 NRL 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. * * The views and conclusions contained in the software and documentation * are those of the authors and should not be interpreted as representing * official policies, either expressed or implied, of the US Naval * Research Laboratory (NRL). */ #include #include #include #include #define MBTYPES #include #include #include #include #include #include #include #include struct mbstat mbstat; /* mbuf stats */ struct pool mbpool; /* mbuf pool */ struct pool mclpool; /* mbuf cluster pool */ int max_linkhdr; /* largest link-level header */ int max_protohdr; /* largest protocol header */ int max_hdr; /* largest link+protocol header */ int max_datalen; /* MHLEN - max_hdr */ struct mbuf *m_copym0(struct mbuf *, int, int, int, int); void nmbclust_update(void); const char *mclpool_warnmsg = "WARNING: mclpool limit reached; increase kern.maxclusters"; /* * Initialize the mbuf allocator. */ void mbinit(void) { pool_init(&mbpool, MSIZE, 0, 0, 0, "mbpl", NULL); pool_init(&mclpool, MCLBYTES, 0, 0, 0, "mclpl", NULL); nmbclust_update(); /* * 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); } void nmbclust_update(void) { /* * 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. */ (void)pool_sethardlimit(&mclpool, nmbclust, mclpool_warnmsg, 60); pool_sethiwat(&mbpool, nmbclust); } void m_reclaim(void *arg, int flags) { struct domain *dp; struct protosw *pr; 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)(); splx(s); mbstat.m_drain++; } /* * Space allocation routines. */ struct mbuf * m_get(int nowait, int type) { struct mbuf *m; int s; s = splvm(); m = pool_get(&mbpool, nowait == M_WAIT ? PR_WAITOK|PR_LIMITFAIL : 0); if (m) { m->m_type = type; mbstat.m_mtypes[type]++; m->m_next = (struct mbuf *)NULL; m->m_nextpkt = (struct mbuf *)NULL; m->m_data = m->m_dat; m->m_flags = 0; } splx(s); return (m); } struct mbuf * m_gethdr(int nowait, int type) { struct mbuf *m; int s; s = splvm(); m = pool_get(&mbpool, nowait == M_WAIT ? PR_WAITOK|PR_LIMITFAIL : 0); if (m) { m->m_type = type; mbstat.m_mtypes[type]++; m->m_next = (struct mbuf *)NULL; m->m_nextpkt = (struct mbuf *)NULL; m->m_data = m->m_pktdat; m->m_flags = M_PKTHDR; m->m_pkthdr.rcvif = NULL; SLIST_INIT(&m->m_pkthdr.tags); m->m_pkthdr.csum_flags = 0; m->m_pkthdr.pf.hdr = NULL; m->m_pkthdr.pf.rtableid = 0; m->m_pkthdr.pf.qid = 0; m->m_pkthdr.pf.tag = 0; m->m_pkthdr.pf.flags = 0; m->m_pkthdr.pf.routed = 0; } splx(s); return (m); } struct mbuf * m_getclr(int nowait, int type) { struct mbuf *m; MGET(m, nowait, type); if (m == NULL) return (NULL); memset(mtod(m, caddr_t), 0, MLEN); return (m); } void m_clget(struct mbuf *m, int how) { int s; s = splvm(); m->m_ext.ext_buf = pool_get(&mclpool, how == M_WAIT ? (PR_WAITOK|PR_LIMITFAIL) : 0); splx(s); if (m->m_ext.ext_buf != NULL) { m->m_data = m->m_ext.ext_buf; m->m_flags |= M_EXT|M_CLUSTER; m->m_ext.ext_size = MCLBYTES; m->m_ext.ext_free = NULL; m->m_ext.ext_arg = NULL; MCLINITREFERENCE(m); } } 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); } while ((m = n) != NULL); } /* * 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; if (len > MHLEN) panic("mbuf prepend length too big"); MGET(mn, how, m->m_type); if (mn == NULL) { m_freem(m); return (NULL); } if (m->m_flags & M_PKTHDR) M_MOVE_PKTHDR(mn, m); mn->m_next = m; m = mn; MH_ALIGN(m, len); m->m_len = len; return (m); } /* * Make a copy of an mbuf chain starting "off" 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 off, int len, int wait) { return m_copym0(m, off, len, wait, 0); /* shallow copy on M_EXT */ } /* * m_copym2() is like m_copym(), except it COPIES cluster mbufs, instead * of merely bumping the reference count. */ struct mbuf * m_copym2(struct mbuf *m, int off, int len, int wait) { return m_copym0(m, off, len, wait, 1); /* deep copy */ } struct mbuf * m_copym0(struct mbuf *m, int off, int len, int wait, int deep) { struct mbuf *n, **np; struct mbuf *top; int copyhdr = 0; if (off < 0 || len < 0) panic("m_copym0: off %d, len %d", off, len); if (off == 0 && m->m_flags & M_PKTHDR) copyhdr = 1; while (off > 0) { if (m == NULL) panic("m_copym0: null mbuf"); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } np = ⊤ top = NULL; while (len > 0) { if (m == NULL) { if (len != M_COPYALL) panic("m_copym0: m == NULL and not COPYALL"); break; } MGET(n, wait, m->m_type); *np = n; if (n == NULL) goto nospace; if (copyhdr) { M_DUP_PKTHDR(n, m); if (len != M_COPYALL) 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 == NULL) MCFail++; 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) panic("m_copydata: off %d < 0", off); if (len < 0) panic("m_copydata: len %d < 0", len); while (off > 0) { if (m == NULL) panic("m_copydata: null mbuf in skip"); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { if (m == NULL) panic("m_copydata: null mbuf"); count = min(m->m_len - off, len); bcopy(mtod(m, caddr_t) + off, cp, count); len -= count; cp += count; off = 0; m = m->m_next; } } /* * Copy data from a buffer back into the indicated mbuf chain, * starting "off" bytes from the beginning, extending the mbuf * chain if necessary. The mbuf needs to be properly initialized * including the setting of m_len. */ void m_copyback(struct mbuf *m0, int off, int len, const void *_cp) { int mlen; struct mbuf *m = m0, *n; int totlen = 0; caddr_t cp = (caddr_t)_cp; if (m0 == NULL) return; while (off > (mlen = m->m_len)) { off -= mlen; totlen += mlen; if (m->m_next == NULL) { n = m_getclr(M_DONTWAIT, m->m_type); if (n == NULL) 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); bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen); cp += mlen; len -= mlen; mlen += off; off = 0; totlen += mlen; if (len == 0) break; if (m->m_next == NULL) { n = m_get(M_DONTWAIT, m->m_type); if (n == NULL) 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; } /* * 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) { while (m->m_next) m = m->m_next; while (n) { if (M_READONLY(m) || n->m_len > M_TRAILINGSPACE(m)) { /* just join the two chains */ m->m_next = n; return; } /* splat the data from one into the other */ bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, (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 == NULL) 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->m_next) != NULL) m->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 == NULL) goto bad; m->m_len = 0; if (n->m_flags & M_PKTHDR) M_MOVE_PKTHDR(m, n); } space = &m->m_dat[MLEN] - (m->m_data + m->m_len); do { count = min(min(max(len, max_protohdr), space), n->m_len); bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, (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); } /* * m_pullup2() works like m_pullup, save that len can be <= MCLBYTES. * m_pullup2() only works on values of len such that MHLEN < len <= MCLBYTES, * it calls m_pullup() for values <= MHLEN. It also only coagulates the * reqested number of bytes. (For those of us who expect unwieldly option * headers. * * KEBE SAYS: Remember that dtom() calls with data in clusters does not work! */ struct mbuf * m_pullup2(struct mbuf *n, int len) { struct mbuf *m; int count; if (len <= MHLEN) return m_pullup(n, len); if ((n->m_flags & M_EXT) != 0 && n->m_data + len < &n->m_data[MCLBYTES] && n->m_next) { if (n->m_len >= len) return (n); m = n; n = n->m_next; len -= m->m_len; } else { if (len > MCLBYTES) goto bad; MGET(m, M_DONTWAIT, n->m_type); if (m == NULL) goto bad; MCLGET(m, M_DONTWAIT); if ((m->m_flags & M_EXT) == 0) goto bad; m->m_len = 0; if (n->m_flags & M_PKTHDR) { /* Too many adverse side effects. */ /* M_MOVE_PKTHDR(m, n); */ m->m_flags = (n->m_flags & M_COPYFLAGS) | M_EXT | M_CLUSTER; M_MOVE_HDR(m, n); /* n->m_data is cool. */ } } do { count = min(len, n->m_len); bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len, (unsigned)count); len -= count; m->m_len += count; n->m_len -= 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); } /* * 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); } /* * Inject a new mbuf chain of length siz in mbuf chain m0 at * position len0. Returns a pointer to the first injected mbuf, or * NULL on failure (m0 is left undisturbed). Note that if there is * enough space for an object of size siz in the appropriate position, * no memory will be allocated. Also, there will be no data movement in * the first len0 bytes (pointers to that will remain valid). * * XXX It is assumed that siz is less than the size of an mbuf at the moment. */ struct mbuf * m_inject(struct mbuf *m0, int len0, int siz, int wait) { struct mbuf *m, *n, *n2 = NULL, *n3; unsigned len = len0, remain; if ((siz >= MHLEN) || (len0 <= 0)) return (NULL); for (m = m0; m && len > m->m_len; m = m->m_next) len -= m->m_len; if (m == NULL) return (NULL); remain = m->m_len - len; if (remain == 0) { if ((m->m_next) && (M_LEADINGSPACE(m->m_next) >= siz)) { m->m_next->m_len += siz; if (m0->m_flags & M_PKTHDR) m0->m_pkthdr.len += siz; m->m_next->m_data -= siz; return m->m_next; } } else { n2 = m_copym2(m, len, remain, wait); if (n2 == NULL) return (NULL); } MGET(n, wait, MT_DATA); if (n == NULL) { if (n2) m_freem(n2); return (NULL); } n->m_len = siz; if (m0->m_flags & M_PKTHDR) m0->m_pkthdr.len += siz; m->m_len -= remain; /* Trim */ if (n2) { for (n3 = n; n3->m_next != NULL; n3 = n3->m_next) ; n3->m_next = n2; } else n3 = n; for (; n3->m_next != NULL; n3 = n3->m_next) ; n3->m_next = m->m_next; m->m_next = n; return n; } /* * 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, olen; for (m = m0; m && len > m->m_len; m = m->m_next) len -= m->m_len; if (m == NULL) return (NULL); remain = m->m_len - len; if (m0->m_flags & M_PKTHDR) { MGETHDR(n, wait, m0->m_type); if (n == NULL) return (NULL); M_DUP_PKTHDR(n, m0); n->m_pkthdr.len -= len0; olen = 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 == NULL) { (void) m_free(n); m0->m_pkthdr.len = olen; return (NULL); } else return (n); } else MH_ALIGN(n, remain); } else if (remain == 0) { n = m->m_next; m->m_next = NULL; return (n); } else { MGET(n, wait, m->m_type); if (n == NULL) return (NULL); 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 { bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain); } n->m_len = remain; m->m_len = len; n->m_next = m->m_next; m->m_next = NULL; return (n); } /* * Routine to copy from device local memory into mbufs. */ struct mbuf * m_devget(char *buf, int totlen, int off, struct ifnet *ifp, void (*copy)(const void *, void *, size_t)) { struct mbuf *m; struct mbuf *top = NULL, **mp = ⊤ int 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 == NULL) return (NULL); m->m_pkthdr.rcvif = ifp; m->m_pkthdr.len = totlen; m->m_len = MHLEN; while (totlen > 0) { if (top != NULL) { MGET(m, M_DONTWAIT, MT_DATA); if (m == NULL) { 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) m->m_len = len = min(len, MCLBYTES); else len = m->m_len; } else { /* * Place initial small packet/header at end of mbuf. */ if (len < m->m_len) { if (top == NULL && 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 bcopy(cp, mtod(m, caddr_t), (size_t)len); cp += len; *mp = m; mp = &m->m_next; totlen -= len; if (cp == epkt) cp = buf; } return (top); } void m_zero(struct mbuf *m) { while (m) { #ifdef DIAGNOSTIC if (M_READONLY(m)) panic("m_zero: M_READONLY"); #endif /* DIAGNOSTIC */ if (m->m_flags & M_EXT) memset(m->m_ext.ext_buf, 0, m->m_ext.ext_size); else { if (m->m_flags & M_PKTHDR) memset(m->m_pktdat, 0, MHLEN); else memset(m->m_dat, 0, MLEN); } m = m->m_next; } } /* * 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)(caddr_t, caddr_t, unsigned int), caddr_t fstate) { int rval; unsigned int count; if (len < 0) panic("m_apply: len %d < 0", len); if (off < 0) panic("m_apply: off %d < 0", off); while (off > 0) { if (m == NULL) panic("m_apply: null mbuf in skip"); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { if (m == NULL) panic("m_apply: null mbuf"); count = min(m->m_len - off, len); rval = f(fstate, mtod(m, caddr_t) + off, count); if (rval) return (rval); len -= count; off = 0; m = m->m_next; } return (0); }