/* uipc_mbuf.c,v 1.84 2004/07/21 12:06:46 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, "uipc_mbuf.c,v 1.84 2004/07/21 12:06:46 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(struct mbuf *, int, int, int, int); static struct mbuf *m_split0(struct mbuf *, int, int, int); static int m_copyback0(struct mbuf **, int, int, const void *, int, int); /* flags for m_copyback0 */ #define M_COPYBACK0_COPYBACK 0x0001 /* copyback from cp */ #define M_COPYBACK0_PRESERVE 0x0002 /* preserve original data */ #define M_COPYBACK0_COW 0x0004 /* do copy-on-write */ #define M_COPYBACK0_EXTEND 0x0008 /* extend chain */ 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 } /* * sysctl helper routine for the kern.mbuf subtree. nmbclusters may * or may not be writable, and mblowat and mcllowat need range * checking and pool tweaking after being reset. */ static int sysctl_kern_mbuf(SYSCTLFN_ARGS) { int error, newval; struct sysctlnode node; node = *rnode; node.sysctl_data = &newval; switch (rnode->sysctl_num) { case MBUF_NMBCLUSTERS: if (mb_map != NULL) { node.sysctl_flags &= ~CTLFLAG_READWRITE; node.sysctl_flags |= CTLFLAG_READONLY; } /* FALLTHROUGH */ case MBUF_MBLOWAT: case MBUF_MCLLOWAT: newval = *(int*)rnode->sysctl_data; break; default: return (EOPNOTSUPP); } error = sysctl_lookup(SYSCTLFN_CALL(&node)); if (error || newp == NULL) return (error); if (newval < 0) return (EINVAL); switch (node.sysctl_num) { case MBUF_NMBCLUSTERS: if (newval < nmbclusters) return (EINVAL); nmbclusters = newval; pool_sethardlimit(&mclpool, nmbclusters, mclpool_warnmsg, 60); break; case MBUF_MBLOWAT: mblowat = newval; pool_setlowat(&mbpool, mblowat); break; case MBUF_MCLLOWAT: mcllowat = newval; pool_setlowat(&mclpool, mcllowat); break; } return (0); } #ifdef MBUFTRACE static int sysctl_kern_mbuf_mowners(SYSCTLFN_ARGS) { struct mowner *mo; size_t len = 0; int error = 0; if (namelen != 0) return (EINVAL); if (newp != NULL) return (EPERM); 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); } if (error == 0) *oldlenp = len; return (error); } #endif /* MBUFTRACE */ SYSCTL_SETUP(sysctl_kern_mbuf_setup, "sysctl kern.mbuf subtree setup") { sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "kern", NULL, NULL, 0, NULL, 0, CTL_KERN, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "mbuf", SYSCTL_DESCR("mbuf control variables"), NULL, 0, NULL, 0, CTL_KERN, KERN_MBUF, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE, CTLTYPE_INT, "msize", SYSCTL_DESCR("mbuf base size"), NULL, msize, NULL, 0, CTL_KERN, KERN_MBUF, MBUF_MSIZE, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE, CTLTYPE_INT, "mclbytes", SYSCTL_DESCR("mbuf cluster size"), NULL, mclbytes, NULL, 0, CTL_KERN, KERN_MBUF, MBUF_MCLBYTES, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "nmbclusters", SYSCTL_DESCR("Limit on the number of mbuf clusters"), sysctl_kern_mbuf, 0, &nmbclusters, 0, CTL_KERN, KERN_MBUF, MBUF_NMBCLUSTERS, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "mblowat", SYSCTL_DESCR("mbuf low water mark"), sysctl_kern_mbuf, 0, &mblowat, 0, CTL_KERN, KERN_MBUF, MBUF_MBLOWAT, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "mcllowat", SYSCTL_DESCR("mbuf cluster low water mark"), sysctl_kern_mbuf, 0, &mcllowat, 0, CTL_KERN, KERN_MBUF, MBUF_MCLLOWAT, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_STRUCT, "stats", SYSCTL_DESCR("mbuf allocation statistics"), NULL, 0, &mbstat, sizeof(mbstat), CTL_KERN, KERN_MBUF, MBUF_STATS, CTL_EOL); #ifdef MBUFTRACE sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_STRUCT, "mowners", SYSCTL_DESCR("Information about mbuf owners"), sysctl_kern_mbuf_mowners, 0, NULL, 0, CTL_KERN, KERN_MBUF, MBUF_MOWNERS, CTL_EOL); #endif /* MBUFTRACE */ } 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; const struct protosw *pr; struct ifnet *ifp; int s = splvm(); DOMAIN_FOREACH(dp) { for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) if (pr->pr_drain) (*pr->pr_drain)(); } IFNET_FOREACH(ifp) { 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 /* * Walk a chain of mbufs, claiming ownership of each mbuf in the chain. */ void m_claimm(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_tag_delete_chain(m, NULL); 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, off %d", off); 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, len %d [!COPYALL]", len); 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, void *vp) { unsigned count; char *cp = vp; if (off < 0 || len < 0) panic("m_copydata: off %d, len %d", off, len); while (off > 0) { if (m == 0) panic("m_copydata: m == 0, off %d", off); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { if (m == 0) panic("m_copydata: m == 0, len %d", len); 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. * 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 */ 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); m_tag_delete_chain(n, NULL); 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); m_tag_delete_chain(n, NULL); 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) { return m_split0(m0, len0, wait, 1); } static struct mbuf * m_split0(struct mbuf *m0, int len0, int wait, int copyhdr) { 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 (copyhdr && (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, const void *cp) { #if defined(DEBUG) struct mbuf *origm = m0; int error; #endif /* defined(DEBUG) */ if (m0 == NULL) return; #if defined(DEBUG) error = #endif /* defined(DEBUG) */ m_copyback0(&m0, off, len, cp, M_COPYBACK0_COPYBACK|M_COPYBACK0_EXTEND, M_DONTWAIT); #if defined(DEBUG) if (error != 0 || (m0 != NULL && origm != m0)) panic("m_copyback"); #endif /* defined(DEBUG) */ } struct mbuf * m_copyback_cow(struct mbuf *m0, int off, int len, const void *cp, int how) { int error; /* don't support chain expansion */ KDASSERT(off + len <= m_length(m0)); error = m_copyback0(&m0, off, len, cp, M_COPYBACK0_COPYBACK|M_COPYBACK0_COW, how); if (error) { /* * no way to recover from partial success. * just free the chain. */ m_freem(m0); return NULL; } return m0; } /* * m_makewritable: ensure the specified range writable. */ int m_makewritable(struct mbuf **mp, int off, int len, int how) { int error; #if defined(DEBUG) struct mbuf *n; int origlen, reslen; origlen = m_length(*mp); #endif /* defined(DEBUG) */ #if 0 /* M_COPYALL is large enough */ if (len == M_COPYALL) len = m_length(*mp) - off; /* XXX */ #endif error = m_copyback0(mp, off, len, NULL, M_COPYBACK0_PRESERVE|M_COPYBACK0_COW, how); #if defined(DEBUG) reslen = 0; for (n = *mp; n; n = n->m_next) reslen += n->m_len; if (origlen != reslen) panic("m_makewritable: length changed"); if (((*mp)->m_flags & M_PKTHDR) != 0 && reslen != (*mp)->m_pkthdr.len) panic("m_makewritable: inconsist"); #endif /* defined(DEBUG) */ return error; } int m_copyback0(struct mbuf **mp0, int off, int len, const void *vp, int flags, int how) { int mlen; struct mbuf *m, *n; struct mbuf **mp; int totlen = 0; const char *cp = vp; KASSERT(mp0 != NULL); KASSERT(*mp0 != NULL); KASSERT((flags & M_COPYBACK0_PRESERVE) == 0 || cp == NULL); KASSERT((flags & M_COPYBACK0_COPYBACK) == 0 || cp != NULL); mp = mp0; m = *mp; while (off > (mlen = m->m_len)) { off -= mlen; totlen += mlen; if (m->m_next == 0) { if ((flags & M_COPYBACK0_EXTEND) == 0) goto out; n = m_getclr(how, m->m_type); if (n == 0) goto out; n->m_len = min(MLEN, len + off); m->m_next = n; } mp = &m->m_next; m = m->m_next; } while (len > 0) { mlen = m->m_len - off; if (mlen != 0 && M_READONLY(m)) { char *datap; int eatlen; /* * this mbuf is read-only. * allocate a new writable mbuf and try again. */ #if defined(DIAGNOSTIC) if ((flags & M_COPYBACK0_COW) == 0) panic("m_copyback0: read-only"); #endif /* defined(DIAGNOSTIC) */ /* * if we're going to write into the middle of * a mbuf, split it first. */ if (off > 0 && len < mlen) { n = m_split0(m, off, how, 0); if (n == NULL) goto enobufs; m->m_next = n; mp = &m->m_next; m = n; off = 0; continue; } /* * XXX TODO coalesce into the trailingspace of * the previous mbuf when possible. */ /* * allocate a new mbuf. copy packet header if needed. */ MGET(n, how, m->m_type); if (n == NULL) goto enobufs; MCLAIM(n, m->m_owner); if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { /* XXX M_MOVE_PKTHDR */ M_COPY_PKTHDR(n, m); n->m_len = MHLEN; } else { if (len >= MINCLSIZE) MCLGET(n, M_DONTWAIT); n->m_len = (n->m_flags & M_EXT) ? MCLBYTES : MLEN; } if (n->m_len > len) n->m_len = len; /* * free the region which has been overwritten. * copying data from old mbufs if requested. */ if (flags & M_COPYBACK0_PRESERVE) datap = mtod(n, char *); else datap = NULL; eatlen = n->m_len; KDASSERT(off == 0 || eatlen >= mlen); if (off > 0) { KDASSERT(len >= mlen); m->m_len = off; m->m_next = n; if (datap) { m_copydata(m, off, mlen, datap); datap += mlen; } eatlen -= mlen; mp = &m->m_next; m = m->m_next; } while (m != NULL && M_READONLY(m) && n->m_type == m->m_type && eatlen > 0) { mlen = min(eatlen, m->m_len); if (datap) { m_copydata(m, 0, mlen, datap); datap += mlen; } m->m_data += mlen; m->m_len -= mlen; eatlen -= mlen; if (m->m_len == 0) *mp = m = m_free(m); } if (eatlen > 0) n->m_len -= eatlen; n->m_next = m; *mp = m = n; continue; } mlen = min(mlen, len); if (flags & M_COPYBACK0_COPYBACK) { 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) { if ((flags & M_COPYBACK0_EXTEND) == 0) goto out; n = m_get(how, m->m_type); if (n == 0) break; n->m_len = min(MLEN, len); m->m_next = n; } mp = &m->m_next; m = m->m_next; } out: if (((m = *mp0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen)) m->m_pkthdr.len = totlen; return 0; enobufs: return ENOBUFS; } /* * 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); }