/* $OpenBSD: uipc_mbuf.c,v 1.64 2004/01/28 20:19:24 dhartmei 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 */ struct vm_map *mb_map; 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 */ void *mclpool_alloc(struct pool *, int); void mclpool_release(struct pool *, void *); struct mbuf *m_copym0(struct mbuf *, int, int, int, int); const char *mclpool_warnmsg = "WARNING: mclpool limit reached; increase NMBCLUSTERS"; struct pool_allocator mclpool_allocator = { mclpool_alloc, mclpool_release, 0, }; /* * Initialize the mbuf allcator. */ void mbinit() { vaddr_t minaddr, maxaddr; minaddr = vm_map_min(kernel_map); mb_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr, nmbclust*(MCLBYTES), VM_MAP_INTRSAFE, FALSE, NULL); 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); /* * 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); /* * 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 * mclpool_alloc(struct pool *pp, int flags) { boolean_t waitok = (flags & PR_WAITOK) ? TRUE : FALSE; return ((void *)uvm_km_alloc_poolpage1(mb_map, uvmexp.mb_object, waitok)); } void mclpool_release(struct pool *pp, void *v) { uvm_km_free_poolpage1(mb_map, (vaddr_t)v); } void m_reclaim(void *arg, int flags) { register struct domain *dp; register struct protosw *pr; int s = splimp(); 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. * These are also available as macros * for critical paths. */ struct mbuf * m_get(nowait, type) int nowait, type; { register struct mbuf *m; MGET(m, nowait, type); return (m); } struct mbuf * m_gethdr(nowait, type) int nowait, type; { register struct mbuf *m; MGETHDR(m, nowait, type); return (m); } struct mbuf * m_getclr(nowait, type) int nowait, type; { register struct mbuf *m; MGET(m, nowait, type); if (m == NULL) return (NULL); memset(mtod(m, caddr_t), 0, MLEN); return (m); } struct mbuf * m_free(m) struct mbuf *m; { register struct mbuf *n; MFREE(m, n); return (n); } void m_freem(m) register struct mbuf *m; { register 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(m, len, how) register struct mbuf *m; int len, how; { struct mbuf *mn; 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; 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(m, off0, len, wait) struct mbuf *m; int off0, wait; int len; { return m_copym0(m, off0, 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(m, off0, len, wait) struct mbuf *m; int off0, wait; int len; { return m_copym0(m, off0, len, wait, 1); /* deep copy */ } struct mbuf * m_copym0(m, off0, len, wait, deep) struct mbuf *m; int off0, wait; int len; int deep; /* deep copy */ { struct mbuf *n, **np; int off = off0; 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 == 0) panic("m_copym0: null mbuf"); 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_copym0: m == 0 and not COPYALL"); break; } MGET(n, wait, m->m_type); *np = n; if (n == 0) goto nospace; if (copyhdr) { M_DUP_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 (0); } /* * Copy data from an mbuf chain starting "off" bytes from the beginning, * continuing for "len" bytes, into the indicated buffer. */ void m_copydata(m, off, len, cp) register struct mbuf *m; register int off; register int len; caddr_t cp; { register 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(m0, off, len, cp) struct mbuf *m0; register int off; register int len; const void *cp; { register int mlen; register 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); 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 == 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; } /* * Concatenate mbuf chain n to m. * Both chains must be of the same type (e.g. MT_DATA). * Any m_pkthdr is not updated. */ void m_cat(m, n) register struct mbuf *m, *n; { 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 */ 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(mp, req_len) struct mbuf *mp; int req_len; { register int len = req_len; register struct mbuf *m; register 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(n, len) register struct mbuf *n; int len; { register struct mbuf *m; register 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(n, len) register struct mbuf *n; int len; { register struct mbuf *m; register int count; int space; 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_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; 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); } /* * Return a pointer to mbuf/offset of location in mbuf chain. */ struct mbuf * m_getptr(m, loc, off) 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(m0, len0, siz, wait) register struct mbuf *m0; int len0, siz, wait; { register 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(m0, len0, wait) register struct mbuf *m0; int len0, wait; { register 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(buf, totlen, off0, ifp, copy) char *buf; int totlen, off0; struct ifnet *ifp; void (*copy)(const void *, void *, size_t); { register struct mbuf *m; struct mbuf *top = NULL, **mp = ⊤ register int off = off0, len; register 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(m) 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(m, off, len, f, fstate) struct mbuf *m; int off; int len; /* fstate, data, 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); } #ifdef SMALL_KERNEL /* * The idea of adding code in a small kernel might look absurd, but this is * instead of macros. */ struct mbuf * _sk_mget(int how, int type) { struct mbuf *m; _MGET(m, how, type); return m; } struct mbuf * _sk_mgethdr(int how, int type) { struct mbuf *m; _MGETHDR(m, how, type); return m; } void _sk_mclget(struct mbuf *m, int how) { _MCLGET(m, how); } #endif /* SMALL_KERNEL */