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IABSD.fr/src/sys/kern/uipc_mbuf2.c
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- sys/kern/uipc_mbuf2.c
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/* $OpenBSD: uipc_mbuf2.c,v 1.50 2025/06/25 20:26:32 miod Exp $ */ /* $KAME: uipc_mbuf2.c,v 1.29 2001/02/14 13:42:10 itojun Exp $ */ /* $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $ */ /* * Copyright (C) 1999 WIDE Project. * 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 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 PROJECT 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 PROJECT 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 <sys/param.h> #include <sys/systm.h> #include <sys/malloc.h> #include <sys/pool.h> #include <sys/percpu.h> #include <sys/mbuf.h> extern struct pool mtagpool; /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */ static struct mbuf *m_dup1(struct mbuf *, int, int, int); /* * ensure that [off, off + len] is contiguous on the mbuf chain "m". * packet chain before "off" is kept untouched. * if offp == NULL, the target will start at <retval, 0> on resulting chain. * if offp != NULL, the target will start at <retval, *offp> on resulting chain. * * on error return (NULL return value), original "m" will be freed. * * XXX m_trailingspace/m_leadingspace on shared cluster (sharedcluster) */ struct mbuf * m_pulldown(struct mbuf *m, int off, int len, int *offp) { struct mbuf *n, *o; int hlen, tlen, olen; int sharedcluster; /* check invalid arguments. */ if (m == NULL) panic("m == NULL in m_pulldown()"); if ((n = m_getptr(m, off, &off)) == NULL) { m_freem(m); return (NULL); /* mbuf chain too short */ } sharedcluster = M_READONLY(n); /* * the target data is on <n, off>. * if we got enough data on the mbuf "n", we're done. */ if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster) goto ok; /* * when len <= n->m_len - off and off != 0, it is a special case. * len bytes from <n, off> sits in single mbuf, but the caller does * not like the starting position (off). * chop the current mbuf into two pieces, set off to 0. */ if (len <= n->m_len - off) { struct mbuf *mlast; mbstat_inc(mbs_pulldown_alloc); o = m_dup1(n, off, n->m_len - off, M_DONTWAIT); if (o == NULL) { m_freem(m); return (NULL); /* ENOBUFS */ } for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next) ; n->m_len = off; mlast->m_next = n->m_next; n->m_next = o; n = o; off = 0; goto ok; } /* * we need to take hlen from <n, off> and tlen from <n->m_next, 0>, * and construct contiguous mbuf with m_len == len. * note that hlen + tlen == len, and tlen > 0. */ hlen = n->m_len - off; tlen = len - hlen; /* * ensure that we have enough trailing data on mbuf chain. * if not, we can do nothing about the chain. */ olen = 0; for (o = n->m_next; o != NULL; o = o->m_next) olen += o->m_len; if (hlen + olen < len) { m_freem(m); return (NULL); /* mbuf chain too short */ } /* * easy cases first. * we need to use m_copydata() to get data from <n->m_next, 0>. */ if ((off == 0 || offp) && m_trailingspace(n) >= tlen && !sharedcluster) { mbstat_inc(mbs_pulldown_copy); m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len); n->m_len += tlen; m_adj(n->m_next, tlen); goto ok; } if ((off == 0 || offp) && m_leadingspace(n->m_next) >= hlen && !sharedcluster && n->m_next->m_len >= tlen) { n->m_next->m_data -= hlen; n->m_next->m_len += hlen; mbstat_inc(mbs_pulldown_copy); memcpy(mtod(n->m_next, caddr_t), mtod(n, caddr_t) + off, hlen); n->m_len -= hlen; n = n->m_next; off = 0; goto ok; } /* * now, we need to do the hard way. don't m_copym as there's no room * on both ends. */ if (len > MAXMCLBYTES) { m_freem(m); return (NULL); } mbstat_inc(mbs_pulldown_alloc); MGET(o, M_DONTWAIT, m->m_type); if (o && len > MLEN) { MCLGETL(o, M_DONTWAIT, len); if ((o->m_flags & M_EXT) == 0) { m_free(o); o = NULL; } } if (!o) { m_freem(m); return (NULL); /* ENOBUFS */ } /* get hlen from <n, off> into <o, 0> */ o->m_len = hlen; memcpy(mtod(o, caddr_t), mtod(n, caddr_t) + off, hlen); n->m_len -= hlen; /* get tlen from <n->m_next, 0> into <o, hlen> */ m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len); o->m_len += tlen; m_adj(n->m_next, tlen); o->m_next = n->m_next; n->m_next = o; n = o; off = 0; ok: KASSERT(n->m_len >= off + len); if (offp) *offp = off; return (n); } static struct mbuf * m_dup1(struct mbuf *m, int off, int len, int wait) { struct mbuf *n; int l; if (len > MAXMCLBYTES) return (NULL); if (off == 0 && (m->m_flags & M_PKTHDR) != 0) { MGETHDR(n, wait, m->m_type); if (n == NULL) return (NULL); if (m_dup_pkthdr(n, m, wait)) { m_free(n); return (NULL); } l = MHLEN; } else { MGET(n, wait, m->m_type); l = MLEN; } if (n && len > l) { MCLGETL(n, wait, len); if ((n->m_flags & M_EXT) == 0) { m_free(n); n = NULL; } } if (!n) return (NULL); m_copydata(m, off, len, mtod(n, caddr_t)); n->m_len = len; return (n); } /* Get a packet tag structure along with specified data following. */ struct m_tag * m_tag_get(int type, int len, int wait) { struct m_tag *t; if (len < 0) return (NULL); if (len > PACKET_TAG_MAXSIZE) panic("requested tag size for pool %#x is too big", type); t = pool_get(&mtagpool, wait == M_WAITOK ? PR_WAITOK : PR_NOWAIT); if (t == NULL) return (NULL); t->m_tag_id = type; t->m_tag_len = len; return (t); } /* Prepend a packet tag. */ void m_tag_prepend(struct mbuf *m, struct m_tag *t) { SLIST_INSERT_HEAD(&m->m_pkthdr.ph_tags, t, m_tag_link); m->m_pkthdr.ph_tagsset |= t->m_tag_id; } /* Unlink and free a packet tag. */ void m_tag_delete(struct mbuf *m, struct m_tag *t) { u_int32_t ph_tagsset = 0; struct m_tag *p; SLIST_REMOVE(&m->m_pkthdr.ph_tags, t, m_tag, m_tag_link); pool_put(&mtagpool, t); SLIST_FOREACH(p, &m->m_pkthdr.ph_tags, m_tag_link) ph_tagsset |= p->m_tag_id; m->m_pkthdr.ph_tagsset = ph_tagsset; } /* Unlink and free a packet tag chain. */ void m_tag_delete_chain(struct mbuf *m) { struct m_tag *p; while ((p = SLIST_FIRST(&m->m_pkthdr.ph_tags)) != NULL) { SLIST_REMOVE_HEAD(&m->m_pkthdr.ph_tags, m_tag_link); pool_put(&mtagpool, p); } m->m_pkthdr.ph_tagsset = 0; } /* Find a tag, starting from a given position. */ struct m_tag * m_tag_find(struct mbuf *m, int type, struct m_tag *t) { struct m_tag *p; if (!(m->m_pkthdr.ph_tagsset & type)) return (NULL); if (t == NULL) p = SLIST_FIRST(&m->m_pkthdr.ph_tags); else p = SLIST_NEXT(t, m_tag_link); while (p != NULL) { if (p->m_tag_id == type) return (p); p = SLIST_NEXT(p, m_tag_link); } return (NULL); } /* Copy a single tag. */ struct m_tag * m_tag_copy(struct m_tag *t, int wait) { struct m_tag *p; p = m_tag_get(t->m_tag_id, t->m_tag_len, wait); if (p == NULL) return (NULL); memcpy(p + 1, t + 1, t->m_tag_len); /* Copy the data */ return (p); } /* * Copy two tag chains. The destination mbuf (to) loses any attached * tags even if the operation fails. This should not be a problem, as * m_tag_copy_chain() is typically called with a newly-allocated * destination mbuf. */ int m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int wait) { struct m_tag *p, *t, *tprev = NULL; m_tag_delete_chain(to); SLIST_FOREACH(p, &from->m_pkthdr.ph_tags, m_tag_link) { t = m_tag_copy(p, wait); if (t == NULL) { m_tag_delete_chain(to); return (ENOBUFS); } if (tprev == NULL) SLIST_INSERT_HEAD(&to->m_pkthdr.ph_tags, t, m_tag_link); else SLIST_INSERT_AFTER(tprev, t, m_tag_link); tprev = t; to->m_pkthdr.ph_tagsset |= t->m_tag_id; } return (0); } /* Get first tag in chain. */ struct m_tag * m_tag_first(struct mbuf *m) { return (SLIST_FIRST(&m->m_pkthdr.ph_tags)); } /* Get next tag in chain. */ struct m_tag * m_tag_next(struct mbuf *m, struct m_tag *t) { return (SLIST_NEXT(t, m_tag_link)); }