/*- * Copyright (c) 1982, 1986, 1988, 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. *
*/
/* * __Userspace__ version of /usr/src/sys/kern/kern_mbuf.c * We are initializing two zones for Mbufs and Clusters. *
*/
#define KIPC_MAX_LINKHDR 4 /* int: max length of link header (see sys/sysclt.h) */ #define KIPC_MAX_PROTOHDR 5 /* int: max length of network header (see sys/sysclt.h)*/ int max_linkhdr = KIPC_MAX_LINKHDR; int max_protohdr = KIPC_MAX_PROTOHDR; /* Size of largest protocol layer header. */
/* * Zones from which we allocate.
*/
sctp_zone_t zone_mbuf;
sctp_zone_t zone_clust;
sctp_zone_t zone_ext_refcnt;
/* __Userspace__ clust_mb_args will be passed as callback data to mb_ctor_clust * and mb_dtor_clust. * Note: I had to use struct clust_args as an encapsulation for an mbuf pointer. * struct mbuf * clust_mb_args; does not work.
*/ struct clust_args clust_mb_args;
/* The following setter function is not yet being enclosed within * #if USING_MBUF_CONSTRUCTOR - #endif, until I have thoroughly tested * mb_dtor_mbuf. See comment there
*/
mbuf_mb_args.flags = 0;
mbuf_mb_args.type = type; #endif /* Mbuf master zone, zone_mbuf, has already been
* created in mbuf_initialize() */
mret = SCTP_ZONE_GET(zone_mbuf, struct mbuf); #ifdefined(SCTP_SIMPLE_ALLOCATOR)
mb_ctor_mbuf(mret, &mbuf_mb_args, 0); #endif /*mret = ((struct mbuf *)umem_cache_alloc(zone_mbuf, UMEM_DEFAULT));*/
/* There are cases when an object available in the current CPU's * loaded magazine and in those cases the object's constructor is not applied. * If that is the case, then we are duplicating constructor initialization here, * so that the mbuf is properly constructed before returning it.
*/ if (mret) { #if USING_MBUF_CONSTRUCTOR if (! (mret->m_type == type) ) {
mbuf_constructor_dup(mret, 0, type);
} #else
mbuf_constructor_dup(mret, 0, type); #endif
/* The following setter function is not yet being enclosed within * #if USING_MBUF_CONSTRUCTOR - #endif, until I have thoroughly tested * mb_dtor_mbuf. See comment there
*/
mbuf_mb_args.flags = M_PKTHDR;
mbuf_mb_args.type = type; #endif
mret = SCTP_ZONE_GET(zone_mbuf, struct mbuf); #ifdefined(SCTP_SIMPLE_ALLOCATOR)
mb_ctor_mbuf(mret, &mbuf_mb_args, 0); #endif /*mret = ((struct mbuf *)umem_cache_alloc(zone_mbuf, UMEM_DEFAULT));*/ /* There are cases when an object available in the current CPU's * loaded magazine and in those cases the object's constructor is not applied. * If that is the case, then we are duplicating constructor initialization here, * so that the mbuf is properly constructed before returning it.
*/ if (mret) { #if USING_MBUF_CONSTRUCTOR if (! ((mret->m_flags & M_PKTHDR) && (mret->m_type == type)) ) {
mbuf_constructor_dup(mret, M_PKTHDR, type);
} #else
mbuf_constructor_dup(mret, M_PKTHDR, type); #endif
} return mret;
}
/* Book keeping. */
len -= size; if (mtail != NULL)
mtail->m_next = mb; else
nm = mb;
mtail = mb;
flags &= ~M_PKTHDR; /* Only valid on the first mbuf. */
} if (flags & M_EOR) {
mtail->m_flags |= M_EOR; /* Only valid on the last mbuf. */
}
/* If mbuf was supplied, append new chain to the end of it. */ if (m != NULL) { for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next);
mtail->m_next = nm;
mtail->m_flags &= ~M_EOR;
} else {
m = nm;
}
return (m);
}
/* * Copy the contents of uio into a properly sized mbuf chain.
*/ struct mbuf *
m_uiotombuf(struct uio *uio, int how, int len, int align, int flags)
{ struct mbuf *m, *mb; int error, length;
ssize_t total; int progress = 0;
/* * len can be zero or an arbitrary large value bound by * the total data supplied by the uio.
*/ if (len > 0)
total = min(uio->uio_resid, len); else
total = uio->uio_resid; /* * The smallest unit returned by m_getm2() is a single mbuf * with pkthdr. We can't align past it.
*/ if (align >= MHLEN) return (NULL); /* * Give us the full allocation or nothing. * If len is zero return the smallest empty mbuf.
*/
m = m_getm2(NULL, (int)max(total + align, 1), how, MT_DATA, flags, 0); if (m == NULL) return (NULL);
m->m_data += align;
/* Fill all mbufs with uio data and update header information. */ for (mb = m; mb != NULL; mb = mb->m_next) {
length = (int)min(M_TRAILINGSPACE(mb), total - progress);
error = uiomove(mtod(mb, void *), length, uio); if (error) {
m_freem(m); return (NULL);
}
/* * Reclaim resources associated with a tag.
*/ static __inlinevoid
m_tag_free(struct m_tag *t)
{
(*t->m_tag_free)(t);
}
/* * Set up the contents of a tag. Note that this does not fill in the free * method; the caller is expected to do that. * * XXX probably should be called m_tag_init, but that was already taken.
*/ static __inlinevoid
m_tag_setup(struct m_tag *t, uint32_t cookie, int type, int len)
{
/* __Userspace__ Add umem_reap here for low memory situation? *
*/
}
/* * __Userspace__ * * Constructor for Mbuf master zone. We have a different constructor * for allocating the cluster. * * The 'arg' pointer points to a mb_args structure which * contains call-specific information required to support the * mbuf allocation API. See user_mbuf.h. * * The flgs parameter below can be UMEM_DEFAULT or UMEM_NOFAIL depending on what * was passed when umem_cache_alloc was called. * TODO: Use UMEM_NOFAIL in umem_cache_alloc and also define a failure handler * and call umem_nofail_callback(my_failure_handler) in the stack initialization routines * The advantage of using UMEM_NOFAIL is that we don't have to check if umem_cache_alloc * was successful or not. The failure handler would take care of it, if we use the UMEM_NOFAIL * flag. * * NOTE Ref: http://docs.sun.com/app/docs/doc/819-2243/6n4i099p2?l=en&a=view&q=umem_zalloc) * The umem_nofail_callback() function sets the **process-wide** UMEM_NOFAIL callback. * It also mentions that umem_nofail_callback is Evolving. *
*/ staticint
mb_ctor_mbuf(void *mem, void *arg, int flgs)
{ #if USING_MBUF_CONSTRUCTOR struct mbuf *m; struct mb_args *args;
int flags; short type;
m = (struct mbuf *)mem;
args = (struct mb_args *)arg;
flags = args->flags;
type = args->type;
/* * __Userspace__ * The Mbuf master zone destructor. * This would be called in response to umem_cache_destroy * TODO: Recheck if this is what we want to do in this destructor. * (Note: the number of times mb_dtor_mbuf is called is equal to the * number of individual mbufs allocated from zone_mbuf.
*/ staticvoid
mb_dtor_mbuf(void *mem, void *arg)
{ struct mbuf *m;
m = (struct mbuf *)mem; if ((m->m_flags & M_PKTHDR) != 0) {
m_tag_delete_chain(m, NULL);
}
}
/* __Userspace__ * The Cluster zone constructor. * * Here the 'arg' pointer points to the Mbuf which we * are configuring cluster storage for. If 'arg' is * empty we allocate just the cluster without setting * the mbuf to it. See mbuf.h.
*/ staticint
mb_ctor_clust(void *mem, void *arg, int flgs)
{
/* mem is of type caddr_t. In sys/types.h we have typedef char * caddr_t; */ /* mb_dtor_clust is called at time of umem_cache_destroy() (the number of times * mb_dtor_clust is called is equal to the number of individual mbufs allocated * from zone_clust. Similarly for mb_dtor_mbuf). * At this point the following: * struct mbuf *m; * m = (struct mbuf *)arg; * assert (*(m->m_ext.ref_cnt) == 0); is not meaningful since m->m_ext.ref_cnt = NULL; * has been done in mb_free_ext().
*/
}
/* Unlink and free a packet tag. */ void
m_tag_delete(struct mbuf *m, struct m_tag *t)
{
KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", (void *)m, (void *)t));
m_tag_unlink(m, t);
m_tag_free(t);
}
/* Unlink and free a packet tag chain, starting from given tag. */ void
m_tag_delete_chain(struct mbuf *m, struct m_tag *t)
{
struct m_tag *p, *q;
KASSERT(m, ("m_tag_delete_chain: null mbuf")); if (t != NULL)
p = t; else
p = SLIST_FIRST(&m->m_pkthdr.tags); if (p == NULL) return; while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
m_tag_delete(m, q);
m_tag_delete(m, p);
}
/* * Free an entire chain of mbufs and associated external buffers, if * applicable.
*/ void
m_freem(struct mbuf *mb)
{ while (mb != NULL)
mb = m_free(mb);
}
/* * __Userspace__ * clean mbufs with M_EXT storage attached to them * if the reference count hits 1.
*/ void
mb_free_ext(struct mbuf *m)
{
int skipmbuf;
KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
/* * check if the header is embedded in the cluster
*/
skipmbuf = (m->m_flags & M_NOFREE);
/* Free the external attached storage if this * mbuf is the only reference to it. *__Userspace__ TODO: jumbo frames *
*/ /* NOTE: We had the same code that SCTP_DECREMENT_AND_CHECK_REFCOUNT reduces to here before but the IPHONE malloc commit had changed this to compare to 0 instead of 1 (see next line). Why? . .. this caused a huge memory leak in Linux.
*/ #ifdef IPHONE if (atomic_fetchadd_int(m->m_ext.ref_cnt, -1) == 0) #else if (SCTP_DECREMENT_AND_CHECK_REFCOUNT(m->m_ext.ref_cnt)) #endif
{ if (m->m_ext.ext_type == EXT_CLUSTER){ #ifdefined(SCTP_SIMPLE_ALLOCATOR)
mb_dtor_clust(m->m_ext.ext_buf, &clust_mb_args); #endif
SCTP_ZONE_FREE(zone_clust, m->m_ext.ext_buf);
SCTP_ZONE_FREE(zone_ext_refcnt, (u_int*)m->m_ext.ref_cnt);
m->m_ext.ref_cnt = NULL;
}
}
if (skipmbuf) return;
/* __Userspace__ Also freeing the storage for ref_cnt * Free this mbuf back to the mbuf zone with all m_ext * information purged.
*/
m->m_ext.ext_buf = NULL;
m->m_ext.ext_free = NULL;
m->m_ext.ext_args = NULL;
m->m_ext.ref_cnt = NULL;
m->m_ext.ext_size = 0;
m->m_ext.ext_type = 0;
m->m_flags &= ~M_EXT; #ifdefined(SCTP_SIMPLE_ALLOCATOR)
mb_dtor_mbuf(m, NULL); #endif
SCTP_ZONE_FREE(zone_mbuf, m);
/*umem_cache_free(zone_mbuf, m);*/
}
/* * "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)
{
/* * 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.
*/ 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_NOWAIT, n->m_type); if (m == NULL) goto bad;
m->m_len = 0; if (n->m_flags & M_PKTHDR)
M_MOVE_PKTHDR(m, n);
}
space = (int)(&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), (u_int)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); return (NULL);
}
staticstruct mbuf *
m_dup1(struct mbuf *m, int off, int len, int wait)
{ struct mbuf *n = NULL; int copyhdr;
if (len > MCLBYTES) return NULL; if (off == 0 && (m->m_flags & M_PKTHDR) != 0)
copyhdr = 1; else
copyhdr = 0; if (len >= MINCLSIZE) { if (copyhdr == 1) {
m_clget(n, wait); /* TODO: include code for copying the header */
m_dup_pkthdr(n, m, wait);
} else
m_clget(n, wait);
} else { if (copyhdr == 1)
n = m_gethdr(wait, m->m_type); else
n = m_get(wait, m->m_type);
} if (!n) return NULL; /* ENOBUFS */
/* Taken from sys/kern/uipc_mbuf2.c */ struct mbuf *
m_pulldown(struct mbuf *m, int off, int len, int *offp)
{ struct mbuf *n, *o; int hlen, tlen, olen; int writable;
#ifdef PULLDOWN_DEBUG
{ struct mbuf *t;
SCTP_DEBUG_USR(SCTP_DEBUG_USR, "before:"); for (t = m; t; t = t->m_next)
SCTP_DEBUG_USR(SCTP_DEBUG_USR, " %d", t->m_len);
SCTP_DEBUG_USR(SCTP_DEBUG_USR, "\n");
} #endif
n = m; while (n != NULL && off > 0) { if (n->m_len > off) break;
off -= n->m_len;
n = n->m_next;
} /* be sure to point non-empty mbuf */ while (n != NULL && n->m_len == 0)
n = n->m_next; if (!n) {
m_freem(m); return NULL; /* mbuf chain too short */
}
/* * 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 && writable) 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) {
o = m_dup1(n, off, n->m_len - off, M_NOWAIT); if (o == NULL) {
m_freem(m); return NULL; /* ENOBUFS */
}
n->m_len = off;
o->m_next = n->m_next;
n->m_next = o;
n = n->m_next;
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) && writable) {
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;
}
/* * now, we need to do the hard way. don't m_copy as there's no room * on both end.
*/ if (len > MLEN)
m_clget(o, M_NOWAIT); /* o = m_getcl(M_NOWAIT, m->m_type, 0);*/ else
o = m_get(M_NOWAIT, m->m_type); 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: #ifdef PULLDOWN_DEBUG
{ struct mbuf *t;
SCTP_DEBUG_USR(SCTP_DEBUG_USR, "after:"); for (t = m; t; t = t->m_next)
SCTP_DEBUG_USR(SCTP_DEBUG_USR, "%c%d", t == n ? '*' : ' ', t->m_len);
SCTP_DEBUG_USR(SCTP_DEBUG_USR, " (off=%d)\n", off);
} #endif if (offp)
*offp = off; return n;
}
/* * Attach the the cluster from *m to *n, set up m_ext in *n * and bump the refcount of the cluster.
*/ staticvoid
mb_dupcl(struct mbuf *n, struct mbuf *m)
{
KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
KASSERT((n->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
/* * 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_TRYWAIT/M_NOWAIT from caller. * Note that the copy is read-only, because clusters are not copied, * only their reference counts are incremented.
*/
struct mbuf *
m_copym(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));
KASSERT(m != NULL, ("m_copym, m is NULL"));
#if !defined(INVARIANTS) if (m == NULL) { return (NULL);
} #endif 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;
} if (copyhdr)
MGETHDR(n, wait, m->m_type); else
MGET(n, 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) {
n->m_data = m->m_data + off;
mb_dupcl(n, m);
} else
memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, (u_int)n->m_len); if (len != M_COPYALL)
len -= n->m_len;
off = 0;
m = m->m_next;
np = &n->m_next;
}
/* * 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, struct mbuf *from, int how)
{
KASSERT(to, ("m_dup_pkthdr: to is NULL"));
KASSERT(from, ("m_dup_pkthdr: from is NULL"));
to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT); if ((to->m_flags & M_EXT) == 0)
to->m_data = to->m_pktdat;
to->m_pkthdr = from->m_pkthdr;
SLIST_INIT(&to->m_pkthdr.tags); return (m_tag_copy_chain(to, from, MBTOM(how)));
}
/* Copy a single tag. */ struct m_tag *
m_tag_copy(struct m_tag *t, int how)
{ struct m_tag *p;
KASSERT(t, ("m_tag_copy: null tag"));
p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how); if (p == NULL) return (NULL);
memcpy(p + 1, t + 1, t->m_tag_len); /* Copy the data */ return p;
}
/* Get a packet tag structure along with specified data following. */ struct m_tag *
m_tag_alloc(uint32_t cookie, int type, int len, int wait)
{ struct m_tag *t;
if (len < 0) return NULL;
t = malloc(len + sizeof(struct m_tag)); if (t == NULL) return NULL;
m_tag_setup(t, cookie, type, len);
t->m_tag_free = m_tag_free_default; return t;
}
/* * 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_get(M_NOWAIT, m->m_type); if (n == NULL) goto out;
memset(mtod(n, caddr_t), 0, MLEN);
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);
memcpy(off + mtod(m, caddr_t), cp, (u_int)mlen);
cp += mlen;
len -= mlen;
mlen += off;
off = 0;
totlen += mlen; if (len == 0) break; if (m->m_next == NULL) {
n = m_get(M_NOWAIT, 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;
}
/* * 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 *, void *, u_int), void *arg)
{
u_int count; int rval;
KASSERT(off >= 0, ("m_apply, negative off %d", off));
KASSERT(len >= 0, ("m_apply, negative len %d", len)); while (off > 0) {
KASSERT(m != NULL, ("m_apply, 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_apply, offset > size of mbuf chain"));
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);
}
/* * Lesser-used path for M_PREPEND: * allocate new mbuf to prepend to chain, * copy junk along.
*/ struct mbuf *
m_prepend(struct mbuf *m, int len, int how)
{ struct mbuf *mn;
if (m->m_flags & M_PKTHDR)
MGETHDR(mn, how, m->m_type); else
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 (m->m_flags & M_PKTHDR) { if (len < MHLEN)
MH_ALIGN(m, len);
} else { if (len < MLEN)
M_ALIGN(m, len);
}
m->m_len = len; return (m);
}
/* * Copy data from an mbuf chain starting "off" bytes from the beginning, * continuing for "len" bytes, into the indicated buffer.
*/ void
m_copydata(conststruct mbuf *m, int off, int len, caddr_t cp)
{
u_int 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);
memcpy(cp, mtod(m, caddr_t) + off, count);
len -= count;
cp += count;
off = 0;
m = m->m_next;
}
}
/* * 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)
{ 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 */
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; if (m->m_next != NULL) {
m_freem(m->m_next);
m->m_next = NULL;
} break;
}
count -= m->m_len;
}
}
}
/* m_split is used within sctp_handle_cookie_echo. */
/* * 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;
u_int len = len0, remain;
/* MBUF_CHECKSLEEP(wait); */ for (m = m0; m && (int)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);
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) {
(void) m_free(n); return (NULL);
} else {
n->m_len = 0; return (n);
}
} else
MH_ALIGN(n, remain);
} elseif (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_data = m->m_data + len;
mb_dupcl(n, m);
} 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 = NULL; return (n);
}
int
pack_send_buffer(caddr_t buffer, struct mbuf* mb){
int count_to_copy; int total_count_copied = 0; int offset = 0;
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.
