/* * Copyright (c) 2004 Jeffrey M. Hsu. All rights reserved. * Copyright (c) 2004 The DragonFly Project. All rights reserved. * * This code is derived from software contributed to The DragonFly Project * by Jeffrey M. Hsu. * * 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 DragonFly Project nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific, prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 * COPYRIGHT HOLDERS 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) 2004 Jeffrey M. Hsu. All rights reserved. * * License terms: all terms for the DragonFly license above plus the following: * * 4. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * * This product includes software developed by Jeffrey M. Hsu * for the DragonFly Project. * * This requirement may be waived with permission from Jeffrey Hsu. * This requirement will sunset and may be removed on July 8 2005, * after which the standard DragonFly license (as shown above) will * apply. */ /* * Copyright (c) 1982, 1986, 1988, 1991, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94 * $FreeBSD: src/sys/kern/uipc_mbuf.c,v 1.51.2.24 2003/04/15 06:59:29 silby Exp $ * $DragonFly: src/sys/kern/uipc_mbuf.c,v 1.52 2005/06/17 18:58:02 dillon Exp $ */ #include "opt_param.h" #include "opt_ddb.h" #include "opt_mbuf_stress_test.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INVARIANTS #include #endif /* * mbuf cluster meta-data */ struct mbcluster { int32_t mcl_refs; void *mcl_data; }; static void mbinit(void *); SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbinit, NULL) static u_long mbtypes[MT_NTYPES]; struct mbstat mbstat; int max_linkhdr; int max_protohdr; int max_hdr; int max_datalen; int m_defragpackets; int m_defragbytes; int m_defraguseless; int m_defragfailure; #ifdef MBUF_STRESS_TEST int m_defragrandomfailures; #endif struct objcache *mbuf_cache, *mbufphdr_cache; struct objcache *mclmeta_cache; struct objcache *mbufcluster_cache, *mbufphdrcluster_cache; int nmbclusters; int nmbufs; SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RW, &max_linkhdr, 0, ""); SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RW, &max_protohdr, 0, ""); SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RW, &max_hdr, 0, ""); SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW, &max_datalen, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, mbuf_wait, CTLFLAG_RW, &mbuf_wait, 0, ""); SYSCTL_STRUCT(_kern_ipc, KIPC_MBSTAT, mbstat, CTLFLAG_RW, &mbstat, mbstat, ""); SYSCTL_OPAQUE(_kern_ipc, OID_AUTO, mbtypes, CTLFLAG_RD, mbtypes, sizeof(mbtypes), "LU", ""); SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters, CTLFLAG_RW, &nmbclusters, 0, "Maximum number of mbuf clusters available"); SYSCTL_INT(_kern_ipc, OID_AUTO, nmbufs, CTLFLAG_RW, &nmbufs, 0, "Maximum number of mbufs available"); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD, &m_defragpackets, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD, &m_defragbytes, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD, &m_defraguseless, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD, &m_defragfailure, 0, ""); #ifdef MBUF_STRESS_TEST SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW, &m_defragrandomfailures, 0, ""); #endif static MALLOC_DEFINE(M_MBUF, "mbuf", "mbuf"); static MALLOC_DEFINE(M_MBUFCL, "mbufcl", "mbufcl"); static MALLOC_DEFINE(M_MCLMETA, "mclmeta", "mclmeta"); static void m_reclaim (void); static void m_mclref(void *arg); static void m_mclfree(void *arg); #ifndef NMBCLUSTERS #define NMBCLUSTERS (512 + maxusers * 16) #endif #ifndef NMBUFS #define NMBUFS (nmbclusters * 2) #endif /* * Perform sanity checks of tunables declared above. */ static void tunable_mbinit(void *dummy) { /* * This has to be done before VM init. */ nmbclusters = NMBCLUSTERS; TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters); nmbufs = NMBUFS; TUNABLE_INT_FETCH("kern.ipc.nmbufs", &nmbufs); /* Sanity checks */ if (nmbufs < nmbclusters * 2) nmbufs = nmbclusters * 2; return; } SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_mbinit, NULL); /* "number of clusters of pages" */ #define NCL_INIT 1 #define NMB_INIT 16 /* * The mbuf object cache only guarantees that m_next and m_nextpkt are * NULL and that m_data points to the beginning of the data area. In * particular, m_len and m_pkthdr.len are uninitialized. It is the * responsibility of the caller to initialize those fields before use. */ static boolean_t __inline mbuf_ctor(void *obj, void *private, int ocflags) { struct mbuf *m = obj; m->m_next = NULL; m->m_nextpkt = NULL; m->m_data = m->m_dat; m->m_flags = 0; return (TRUE); } /* * Initialize the mbuf and the packet header fields. */ static boolean_t mbufphdr_ctor(void *obj, void *private, int ocflags) { struct mbuf *m = obj; m->m_next = NULL; m->m_nextpkt = NULL; m->m_data = m->m_pktdat; m->m_flags = M_PKTHDR | M_PHCACHE; m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */ SLIST_INIT(&m->m_pkthdr.tags); m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */ m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */ return (TRUE); } /* * A mbcluster object consists of 2K (MCLBYTES) cluster and a refcount. */ static boolean_t mclmeta_ctor(void *obj, void *private, int ocflags) { struct mbcluster *cl = obj; void *buf; if (ocflags & M_NOWAIT) buf = malloc(MCLBYTES, M_MBUFCL, M_NOWAIT | M_ZERO); else buf = malloc(MCLBYTES, M_MBUFCL, M_INTWAIT | M_ZERO); if (buf == NULL) return (FALSE); cl->mcl_refs = 0; cl->mcl_data = buf; return (TRUE); } static void mclmeta_dtor(void *obj, void *private) { struct mbcluster *mcl = obj; KKASSERT(mcl->mcl_refs == 0); free(mcl->mcl_data, M_MBUFCL); } static void linkcluster(struct mbuf *m, struct mbcluster *cl) { /* * Add the cluster to the mbuf. The caller will detect that the * mbuf now has an attached cluster. */ m->m_ext.ext_arg = cl; m->m_ext.ext_buf = cl->mcl_data; m->m_ext.ext_ref = m_mclref; m->m_ext.ext_free = m_mclfree; m->m_ext.ext_size = MCLBYTES; ++cl->mcl_refs; m->m_data = m->m_ext.ext_buf; m->m_flags |= M_EXT | M_EXT_CLUSTER; } static boolean_t mbufphdrcluster_ctor(void *obj, void *private, int ocflags) { struct mbuf *m = obj; struct mbcluster *cl; mbufphdr_ctor(obj, private, ocflags); cl = objcache_get(mclmeta_cache, ocflags); if (cl == NULL) return (FALSE); m->m_flags |= M_CLCACHE; linkcluster(m, cl); return (TRUE); } static boolean_t mbufcluster_ctor(void *obj, void *private, int ocflags) { struct mbuf *m = obj; struct mbcluster *cl; mbuf_ctor(obj, private, ocflags); cl = objcache_get(mclmeta_cache, ocflags); if (cl == NULL) return (FALSE); m->m_flags |= M_CLCACHE; linkcluster(m, cl); return (TRUE); } /* * Used for both the cluster and cluster PHDR caches. * * The mbuf may have lost its cluster due to sharing, deal * with the situation by checking M_EXT. */ static void mbufcluster_dtor(void *obj, void *private) { struct mbuf *m = obj; struct mbcluster *mcl; if (m->m_flags & M_EXT) { KKASSERT((m->m_flags & M_EXT_CLUSTER) != 0); mcl = m->m_ext.ext_arg; KKASSERT(mcl->mcl_refs == 1); mcl->mcl_refs = 0; objcache_put(mclmeta_cache, mcl); } } struct objcache_malloc_args mbuf_malloc_args = { MSIZE, M_MBUF }; struct objcache_malloc_args mclmeta_malloc_args = { sizeof(struct mbcluster), M_MCLMETA }; /* ARGSUSED*/ static void mbinit(void *dummy) { mbstat.m_msize = MSIZE; mbstat.m_mclbytes = MCLBYTES; mbstat.m_minclsize = MINCLSIZE; mbstat.m_mlen = MLEN; mbstat.m_mhlen = MHLEN; mbuf_cache = objcache_create("mbuf", nmbufs, 0, mbuf_ctor, null_dtor, NULL, objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args); mbufphdr_cache = objcache_create("mbuf pkt hdr", nmbufs, 64, mbufphdr_ctor, null_dtor, NULL, objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args); mclmeta_cache = objcache_create("cluster mbuf", nmbclusters , 0, mclmeta_ctor, mclmeta_dtor, NULL, objcache_malloc_alloc, objcache_malloc_free, &mclmeta_malloc_args); mbufcluster_cache = objcache_create("mbuf + cluster", nmbclusters, 0, mbufcluster_ctor, mbufcluster_dtor, NULL, objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args); mbufphdrcluster_cache = objcache_create("mbuf pkt hdr + cluster", nmbclusters, 64, mbufphdrcluster_ctor, mbufcluster_dtor, NULL, objcache_malloc_alloc, objcache_malloc_free, &mbuf_malloc_args); return; } /* * Return the number of references to this mbuf's data. 0 is returned * if the mbuf is not M_EXT, a reference count is returned if it is * M_EXT | M_EXT_CLUSTER, and 99 is returned if it is a special M_EXT. */ int m_sharecount(struct mbuf *m) { switch (m->m_flags & (M_EXT | M_EXT_CLUSTER)) { case 0: return (0); case M_EXT: return (99); case M_EXT | M_EXT_CLUSTER: return (((struct mbcluster *)m->m_ext.ext_arg)->mcl_refs); } /* NOTREACHED */ return (0); /* to shut up compiler */ } /* * change mbuf to new type */ void m_chtype(struct mbuf *m, int type) { crit_enter(); ++mbtypes[type]; --mbtypes[m->m_type]; m->m_type = type; crit_exit(); } static void m_reclaim(void) { struct domain *dp; struct protosw *pr; crit_enter(); SLIST_FOREACH(dp, &domains, dom_next) { for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) { if (pr->pr_drain) (*pr->pr_drain)(); } } crit_exit(); mbstat.m_drain++; } static void __inline updatestats(struct mbuf *m, int type) { m->m_type = type; crit_enter(); ++mbtypes[type]; ++mbstat.m_mbufs; crit_exit(); } /* * Allocate an mbuf. */ struct mbuf * m_get(int how, int type) { struct mbuf *m; int ntries = 0; int ocf = MBTOM(how); retryonce: m = objcache_get(mbuf_cache, ocf); if (m == NULL) { if ((how & MB_TRYWAIT) && ntries++ == 0) { struct objcache *reclaimlist[] = { mbufphdr_cache, mbufcluster_cache, mbufphdrcluster_cache }; const int nreclaims = __arysize(reclaimlist); if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf)) m_reclaim(); goto retryonce; } return (NULL); } updatestats(m, type); return (m); } struct mbuf * m_gethdr(int how, int type) { struct mbuf *m; int ocf = MBTOM(how); int ntries = 0; retryonce: m = objcache_get(mbufphdr_cache, ocf); if (m == NULL) { if ((how & MB_TRYWAIT) && ntries++ == 0) { struct objcache *reclaimlist[] = { mbuf_cache, mbufcluster_cache, mbufphdrcluster_cache }; const int nreclaims = __arysize(reclaimlist); if (!objcache_reclaimlist(reclaimlist, nreclaims, ocf)) m_reclaim(); goto retryonce; } return (NULL); } updatestats(m, type); return (m); } /* * Get a mbuf (not a mbuf cluster!) and zero it. * Deprecated. */ struct mbuf * m_getclr(int how, int type) { struct mbuf *m; m = m_get(how, type); if (m != NULL) bzero(m->m_data, MLEN); return (m); } /* * Returns an mbuf with an attached cluster. * Because many network drivers use this kind of buffers a lot, it is * convenient to keep a small pool of free buffers of this kind. * Even a small size such as 10 gives about 10% improvement in the * forwarding rate in a bridge or router. */ struct mbuf * m_getcl(int how, short type, int flags) { struct mbuf *m; int ocflags = MBTOM(how); int ntries = 0; retryonce: if (flags & M_PKTHDR) m = objcache_get(mbufphdrcluster_cache, ocflags); else m = objcache_get(mbufcluster_cache, ocflags); if (m == NULL) { if ((how & MB_TRYWAIT) && ntries++ == 0) { struct objcache *reclaimlist[1]; if (flags & M_PKTHDR) reclaimlist[0] = mbufcluster_cache; else reclaimlist[0] = mbufphdrcluster_cache; if (!objcache_reclaimlist(reclaimlist, 1, ocflags)) m_reclaim(); goto retryonce; } return (NULL); } m->m_type = type; crit_enter(); ++mbtypes[type]; ++mbstat.m_clusters; crit_exit(); return (m); } /* * Allocate chain of requested length. */ struct mbuf * m_getc(int len, int how, int type) { struct mbuf *n, *nfirst = NULL, **ntail = &nfirst; int nsize; while (len > 0) { n = m_getl(len, how, type, 0, &nsize); if (n == NULL) goto failed; n->m_len = 0; *ntail = n; ntail = &n->m_next; len -= nsize; } return (nfirst); failed: m_freem(nfirst); return (NULL); } /* * Allocate len-worth of mbufs and/or mbuf clusters (whatever fits best) * and return a pointer to the head of the allocated chain. If m0 is * non-null, then we assume that it is a single mbuf or an mbuf chain to * which we want len bytes worth of mbufs and/or clusters attached, and so * if we succeed in allocating it, we will just return a pointer to m0. * * If we happen to fail at any point during the allocation, we will free * up everything we have already allocated and return NULL. * * Deprecated. Use m_getc() and m_cat() instead. */ struct mbuf * m_getm(struct mbuf *m0, int len, int how, int type) { struct mbuf *nfirst; nfirst = m_getc(len, how, type); if (m0 != NULL) { m_last(m0)->m_next = nfirst; return (m0); } return (nfirst); } /* * Adds a cluster to a normal mbuf, M_EXT is set on success. * Deprecated. Use m_getcl() instead. */ void m_mclget(struct mbuf *m, int how) { struct mbcluster *mcl; KKASSERT((m->m_flags & M_EXT) == 0); mcl = objcache_get(mclmeta_cache, MBTOM(how)); if (mcl != NULL) { linkcluster(m, mcl); crit_enter(); ++mbstat.m_clusters; /* leave the m_mbufs count intact for original mbuf */ crit_exit(); } } static void m_mclref(void *arg) { struct mbcluster *mcl = arg; atomic_add_int(&mcl->mcl_refs, 1); } static void m_mclfree(void *arg) { struct mbcluster *mcl = arg; /* XXX interrupt race. Currently called from a critical section */ if (mcl->mcl_refs > 1) { atomic_subtract_int(&mcl->mcl_refs, 1); } else { KKASSERT(mcl->mcl_refs == 1); mcl->mcl_refs = 0; objcache_put(mclmeta_cache, mcl); } } extern void db_print_backtrace(void); /* * Free a single mbuf and any associated external storage. The successor, * if any, is returned. * * We do need to check non-first mbuf for m_aux, since some of existing * code does not call M_PREPEND properly. * (example: call to bpf_mtap from drivers) */ struct mbuf * m_free(struct mbuf *m) { struct mbuf *n; KASSERT(m->m_type != MT_FREE, ("freeing free mbuf %p", m)); --mbtypes[m->m_type]; n = m->m_next; /* * Make sure the mbuf is in constructed state before returning it * to the objcache. */ m->m_next = NULL; #ifdef notyet KKASSERT(m->m_nextpkt == NULL); #else if (m->m_nextpkt != NULL) { #ifdef DDB static int afewtimes = 10; if (afewtimes-- > 0) { printf("mfree: m->m_nextpkt != NULL\n"); db_print_backtrace(); } #endif m->m_nextpkt = NULL; } #endif if (m->m_flags & M_PKTHDR) { m_tag_delete_chain(m); /* eliminate XXX JH */ } m->m_flags &= (M_EXT | M_EXT_CLUSTER | M_CLCACHE | M_PHCACHE); /* * Clean the M_PKTHDR state so we can return the mbuf to its original * cache. This is based on the PHCACHE flag which tells us whether * the mbuf was originally allocated out of a packet-header cache * or a non-packet-header cache. */ if (m->m_flags & M_PHCACHE) { m->m_flags |= M_PKTHDR; m->m_pkthdr.rcvif = NULL; /* eliminate XXX JH */ m->m_pkthdr.csum_flags = 0; /* eliminate XXX JH */ m->m_pkthdr.fw_flags = 0; /* eliminate XXX JH */ SLIST_INIT(&m->m_pkthdr.tags); } /* * Handle remaining flags combinations. M_CLCACHE tells us whether * the mbuf was originally allocated from a cluster cache or not, * and is totally separate from whether the mbuf is currently * associated with a cluster. */ crit_enter(); switch(m->m_flags & (M_CLCACHE | M_EXT | M_EXT_CLUSTER)) { case M_CLCACHE | M_EXT | M_EXT_CLUSTER: /* * mbuf+cluster cache case. The mbuf was allocated from the * combined mbuf_cluster cache and can be returned to the * cache if the cluster hasn't been shared. */ if (m_sharecount(m) == 1) { /* * The cluster has not been shared, we can just * reset the data pointer and return the mbuf * to the cluster cache. Note that the reference * count is left intact (it is still associated with * an mbuf). */ m->m_data = m->m_ext.ext_buf; if (m->m_flags & M_PHCACHE) objcache_put(mbufphdrcluster_cache, m); else objcache_put(mbufcluster_cache, m); } else { /* * Hell. Someone else has a ref on this cluster, * we have to disconnect it which means we can't * put it back into the mbufcluster_cache, we * have to destroy the mbuf. * * XXX we could try to connect another cluster to * it. */ m->m_ext.ext_free(m->m_ext.ext_arg); m->m_flags &= ~(M_EXT | M_EXT_CLUSTER); if (m->m_flags & M_PHCACHE) objcache_dtor(mbufphdrcluster_cache, m); else objcache_dtor(mbufcluster_cache, m); } --mbstat.m_clusters; break; case M_EXT | M_EXT_CLUSTER: /* * Normal cluster associated with an mbuf that was allocated * from the normal mbuf pool rather then the cluster pool. * The cluster has to be independantly disassociated from the * mbuf. */ --mbstat.m_clusters; /* fall through */ case M_EXT: /* * Normal cluster association case, disconnect the cluster from * the mbuf. The cluster may or may not be custom. */ m->m_ext.ext_free(m->m_ext.ext_arg); m->m_flags &= ~(M_EXT | M_EXT_CLUSTER); /* fall through */ case 0: /* * return the mbuf to the mbuf cache. */ if (m->m_flags & M_PHCACHE) { m->m_data = m->m_pktdat; objcache_put(mbufphdr_cache, m); } else { m->m_data = m->m_dat; objcache_put(mbuf_cache, m); } --mbstat.m_mbufs; break; default: if (!panicstr) panic("bad mbuf flags %p %08x\n", m, m->m_flags); break; } crit_exit(); return (n); } void m_freem(struct mbuf *m) { crit_enter(); while (m) m = m_free(m); crit_exit(); } /* * mbuf utility routines */ /* * Lesser-used path for M_PREPEND: allocate new mbuf to prepend to chain and * copy junk along. */ struct mbuf * m_prepend(struct mbuf *m, int len, int how) { struct mbuf *mn; if (m->m_flags & M_PKTHDR) mn = m_gethdr(how, m->m_type); else mn = m_get(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 MB_WAIT/MB_DONTWAIT from caller. * Note that the copy is read-only, because clusters are not copied, * only their reference counts are incremented. */ struct mbuf * m_copym(const struct mbuf *m, int off0, int len, int wait) { struct mbuf *n, **np; int off = off0; struct mbuf *top; int copyhdr = 0; KASSERT(off >= 0, ("m_copym, negative off %d", off)); KASSERT(len >= 0, ("m_copym, negative len %d", len)); if (off == 0 && m->m_flags & M_PKTHDR) copyhdr = 1; while (off > 0) { KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain")); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } np = ⊤ top = 0; while (len > 0) { if (m == NULL) { KASSERT(len == M_COPYALL, ("m_copym, length > size of mbuf chain")); break; } /* * Because we are sharing any cluster attachment below, * be sure to get an mbuf that does not have a cluster * associated with it. */ if (copyhdr) n = m_gethdr(wait, m->m_type); else n = m_get(wait, m->m_type); *np = n; if (n == NULL) goto nospace; if (copyhdr) { if (!m_dup_pkthdr(n, m, wait)) goto nospace; 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) { KKASSERT((n->m_flags & M_EXT) == 0); n->m_data = m->m_data + off; m->m_ext.ext_ref(m->m_ext.ext_arg); n->m_ext = m->m_ext; n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); } else { bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t), (unsigned)n->m_len); } if (len != M_COPYALL) len -= n->m_len; off = 0; m = m->m_next; np = &n->m_next; } if (top == NULL) mbstat.m_mcfail++; return (top); nospace: m_freem(top); mbstat.m_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)'. * Note that the copy is read-only, because clusters are not copied, * only their reference counts are incremented. * Preserve alignment of the first mbuf so if the creator has left * some room at the beginning (e.g. for inserting protocol headers) * the copies also have the room available. */ struct mbuf * m_copypacket(struct mbuf *m, int how) { struct mbuf *top, *n, *o; n = m_gethdr(how, m->m_type); top = n; if (!n) goto nospace; if (!m_dup_pkthdr(n, m, how)) goto nospace; n->m_len = m->m_len; if (m->m_flags & M_EXT) { KKASSERT((n->m_flags & M_EXT) == 0); n->m_data = m->m_data; m->m_ext.ext_ref(m->m_ext.ext_arg); n->m_ext = m->m_ext; n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); } else { n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat ); bcopy(mtod(m, char *), mtod(n, char *), n->m_len); } m = m->m_next; while (m) { o = m_get(how, m->m_type); if (!o) goto nospace; n->m_next = o; n = n->m_next; n->m_len = m->m_len; if (m->m_flags & M_EXT) { KKASSERT((n->m_flags & M_EXT) == 0); n->m_data = m->m_data; m->m_ext.ext_ref(m->m_ext.ext_arg); n->m_ext = m->m_ext; n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); } else { bcopy(mtod(m, char *), mtod(n, char *), n->m_len); } m = m->m_next; } return top; nospace: m_freem(top); mbstat.m_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(const struct mbuf *m, int off, int len, caddr_t cp) { unsigned count; KASSERT(off >= 0, ("m_copydata, negative off %d", off)); KASSERT(len >= 0, ("m_copydata, negative len %d", len)); while (off > 0) { KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain")); if (off < m->m_len) break; off -= m->m_len; m = m->m_next; } while (len > 0) { KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain")); 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 a packet header mbuf chain into a completely new chain, including * copying any mbuf clusters. Use this instead of m_copypacket() when * you need a writable copy of an mbuf chain. */ struct mbuf * m_dup(struct mbuf *m, int how) { struct mbuf **p, *top = NULL; int remain, moff, nsize; /* Sanity check */ if (m == NULL) return (NULL); KASSERT((m->m_flags & M_PKTHDR) != 0, ("%s: !PKTHDR", __func__)); /* While there's more data, get a new mbuf, tack it on, and fill it */ remain = m->m_pkthdr.len; moff = 0; p = ⊤ while (remain > 0 || top == NULL) { /* allow m->m_pkthdr.len == 0 */ struct mbuf *n; /* Get the next new mbuf */ n = m_getl(remain, how, m->m_type, top == NULL ? M_PKTHDR : 0, &nsize); if (n == NULL) goto nospace; if (top == NULL) if (!m_dup_pkthdr(n, m, how)) goto nospace0; /* Link it into the new chain */ *p = n; p = &n->m_next; /* Copy data from original mbuf(s) into new mbuf */ n->m_len = 0; while (n->m_len < nsize && m != NULL) { int chunk = min(nsize - n->m_len, m->m_len - moff); bcopy(m->m_data + moff, n->m_data + n->m_len, chunk); moff += chunk; n->m_len += chunk; remain -= chunk; if (moff == m->m_len) { m = m->m_next; moff = 0; } } /* Check correct total mbuf length */ KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL), ("%s: bogus m_pkthdr.len", __func__)); } return (top); nospace: m_freem(top); nospace0: mbstat.m_mcfail++; return (NULL); } /* * 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(struct mbuf *m, struct mbuf *n) { m = m_last(m); 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(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; } } /* * Rearrange an mbuf chain so that len bytes are contiguous * and in the data area of an mbuf (so that mtod 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. */ 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) && 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; if (n->m_flags & M_PKTHDR) m = m_gethdr(MB_DONTWAIT, n->m_type); else m = m_get(MB_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) { m_free(m); goto bad; } m->m_next = n; return (m); bad: m_freem(n); mbstat.m_mpfail++; 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. * * Note that the resulting mbufs might be read-only, because the new * mbuf can end up sharing an mbuf cluster with the original mbuf if * the "breaking point" happens to lie within a cluster mbuf. Use the * M_WRITABLE() macro to check for this case. */ struct mbuf * m_split(struct mbuf *m0, int len0, int wait) { struct mbuf *m, *n; unsigned len = len0, remain; 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) { n = m_gethdr(wait, m0->m_type); if (n == NULL) return (NULL); n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif; n->m_pkthdr.len = m0->m_pkthdr.len - len0; 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) { m_free(n); return (NULL); } else { n->m_len = 0; return (n); } } else MH_ALIGN(n, remain); } else if (remain == 0) { n = m->m_next; m->m_next = 0; return (n); } else { n = m_get(wait, m->m_type); if (n == NULL) return (NULL); M_ALIGN(n, remain); } extpacket: if (m->m_flags & M_EXT) { KKASSERT((n->m_flags & M_EXT) == 0); n->m_data = m->m_data + len; m->m_ext.ext_ref(m->m_ext.ext_arg); n->m_ext = m->m_ext; n->m_flags |= m->m_flags & (M_EXT | M_EXT_CLUSTER); } 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 = 0; return (n); } /* * Routine to copy from device local memory into mbufs. * Note: "offset" is ill-defined and always called as 0, so ignore it. */ struct mbuf * m_devget(char *buf, int len, int offset, struct ifnet *ifp, void (*copy)(volatile const void *from, volatile void *to, size_t length)) { struct mbuf *m, *mfirst = NULL, **mtail; int nsize, flags; if (copy == NULL) copy = bcopy; mtail = &mfirst; flags = M_PKTHDR; while (len > 0) { m = m_getl(len, MB_DONTWAIT, MT_DATA, flags, &nsize); if (m == NULL) { m_freem(mfirst); return (NULL); } m->m_len = min(len, nsize); if (flags & M_PKTHDR) { if (len + max_linkhdr <= nsize) m->m_data += max_linkhdr; m->m_pkthdr.rcvif = ifp; m->m_pkthdr.len = len; flags = 0; } copy(buf, m->m_data, (unsigned)m->m_len); buf += m->m_len; len -= m->m_len; *mtail = m; mtail = &m->m_next; } return (mfirst); } /* * 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 == NULL) return; while (off > (mlen = m->m_len)) { off -= mlen; totlen += mlen; if (m->m_next == NULL) { n = m_getclr(MB_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(MB_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; } void m_print(const struct mbuf *m) { int len; const struct mbuf *m2; len = m->m_pkthdr.len; m2 = m; while (len) { printf("%p %*D\n", m2, m2->m_len, (u_char *)m2->m_data, "-"); len -= m2->m_len; m2 = m2->m_next; } return; } /* * "Move" mbuf pkthdr from "from" to "to". * "from" must have M_PKTHDR set, and "to" must be empty. */ void m_move_pkthdr(struct mbuf *to, struct mbuf *from) { KASSERT((to->m_flags & M_PKTHDR), ("m_move_pkthdr: not packet header")); to->m_flags |= from->m_flags & M_COPYFLAGS; to->m_pkthdr = from->m_pkthdr; /* especially tags */ SLIST_INIT(&from->m_pkthdr.tags); /* purge tags from src */ } /* * Duplicate "from"'s mbuf pkthdr in "to". * "from" must have M_PKTHDR set, and "to" must be empty. * In particular, this does a deep copy of the packet tags. */ int m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how) { KASSERT((to->m_flags & M_PKTHDR), ("m_dup_pkthdr: not packet header")); to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & ~M_COPYFLAGS); to->m_pkthdr = from->m_pkthdr; SLIST_INIT(&to->m_pkthdr.tags); return (m_tag_copy_chain(to, from, how)); } /* * Defragment a mbuf chain, returning the shortest possible * chain of mbufs and clusters. If allocation fails and * this cannot be completed, NULL will be returned, but * the passed in chain will be unchanged. Upon success, * the original chain will be freed, and the new chain * will be returned. * * If a non-packet header is passed in, the original * mbuf (chain?) will be returned unharmed. * * m_defrag_nofree doesn't free the passed in mbuf. */ struct mbuf * m_defrag(struct mbuf *m0, int how) { struct mbuf *m_new; if ((m_new = m_defrag_nofree(m0, how)) == NULL) return (NULL); if (m_new != m0) m_freem(m0); return (m_new); } struct mbuf * m_defrag_nofree(struct mbuf *m0, int how) { struct mbuf *m_new = NULL, *m_final = NULL; int progress = 0, length, nsize; if (!(m0->m_flags & M_PKTHDR)) return (m0); #ifdef MBUF_STRESS_TEST if (m_defragrandomfailures) { int temp = arc4random() & 0xff; if (temp == 0xba) goto nospace; } #endif m_final = m_getl(m0->m_pkthdr.len, how, MT_DATA, M_PKTHDR, &nsize); if (m_final == NULL) goto nospace; m_final->m_len = 0; /* in case m0->m_pkthdr.len is zero */ if (m_dup_pkthdr(m_final, m0, how) == NULL) goto nospace; m_new = m_final; while (progress < m0->m_pkthdr.len) { length = m0->m_pkthdr.len - progress; if (length > MCLBYTES) length = MCLBYTES; if (m_new == NULL) { m_new = m_getl(length, how, MT_DATA, 0, &nsize); if (m_new == NULL) goto nospace; } m_copydata(m0, progress, length, mtod(m_new, caddr_t)); progress += length; m_new->m_len = length; if (m_new != m_final) m_cat(m_final, m_new); m_new = NULL; } if (m0->m_next == NULL) m_defraguseless++; m_defragpackets++; m_defragbytes += m_final->m_pkthdr.len; return (m_final); nospace: m_defragfailure++; if (m_new) m_free(m_new); m_freem(m_final); return (NULL); } /* * Move data from uio into mbufs. */ struct mbuf * m_uiomove(struct uio *uio) { struct mbuf *m; /* current working mbuf */ struct mbuf *head = NULL; /* result mbuf chain */ struct mbuf **mp = &head; int resid = uio->uio_resid, nsize, flags = M_PKTHDR, error; do { m = m_getl(resid, MB_WAIT, MT_DATA, flags, &nsize); if (flags) { m->m_pkthdr.len = 0; /* Leave room for protocol headers. */ if (resid < MHLEN) MH_ALIGN(m, resid); flags = 0; } m->m_len = min(nsize, resid); error = uiomove(mtod(m, caddr_t), m->m_len, uio); if (error) { m_free(m); goto failed; } *mp = m; mp = &m->m_next; head->m_pkthdr.len += m->m_len; resid -= m->m_len; } while (resid > 0); return (head); failed: m_freem(head); return (NULL); } struct mbuf * m_last(struct mbuf *m) { while (m->m_next) m = m->m_next; return (m); } /* * Return the number of bytes in an mbuf chain. * If lastm is not NULL, also return the last mbuf. */ u_int m_lengthm(struct mbuf *m, struct mbuf **lastm) { u_int len = 0; struct mbuf *prev = m; while (m) { len += m->m_len; prev = m; m = m->m_next; } if (lastm != NULL) *lastm = prev; return (len); } /* * Like m_lengthm(), except also keep track of mbuf usage. */ u_int m_countm(struct mbuf *m, struct mbuf **lastm, u_int *pmbcnt) { u_int len = 0, mbcnt = 0; struct mbuf *prev = m; while (m) { len += m->m_len; mbcnt += MSIZE; if (m->m_flags & M_EXT) mbcnt += m->m_ext.ext_size; prev = m; m = m->m_next; } if (lastm != NULL) *lastm = prev; *pmbcnt = mbcnt; return (len); }