diff options
| -rw-r--r-- | share/man/man9/Makefile | 12 | ||||
| -rw-r--r-- | share/man/man9/mbuf.9 | 607 |
2 files changed, 617 insertions, 2 deletions
diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile index 6ad8170411a..966c8f3f61b 100644 --- a/share/man/man9/Makefile +++ b/share/man/man9/Makefile @@ -1,4 +1,4 @@ -# $OpenBSD: Makefile,v 1.42 2001/10/04 22:33:49 gluk Exp $ +# $OpenBSD: Makefile,v 1.43 2001/12/06 10:08:47 jjbg Exp $ # $NetBSD: Makefile,v 1.4 1996/01/09 03:23:01 thorpej Exp $ # Makefile for section 9 (kernel function and variable) manual pages. @@ -8,7 +8,7 @@ MAN= altq.9 audio.9 boot.9 bus_dma.9 bus_space.9 copy.9 crypto.9 ctxsw.9 \ dohooks.9 dopowerhooks.9 doshutdownhooks.9 dostartuphooks.9 \ fetch.9 fork1.9 extent.9 \ hardclock.9 hook_establish.9 hz.9 hzto.9 intro.9 inittodr.9 log.9 \ - kthread.9 malloc.9 mbuf_tags.9 md5.9 microtime.9 \ + kthread.9 malloc.9 mbuf.9 mbuf_tags.9 md5.9 microtime.9 \ panic.9 pfind.9 physio.9 \ pool.9 powerhook_establish.9 ppsratecheck.9 printf.9 psignal.9 \ ratecheck.9 resettodr.9 radio.9 random.9 \ @@ -73,6 +73,14 @@ MLINKS+=kthread.9 kthread_create.9 kthread.9 kthread_exit.9 \ kthread.9 kthread_create_deferred.9 MLINKS+=log.9 addlog.9 MLINKS+=md5.9 MD5Init.9 md5.9 MD5Transform.9 +MLINKS+=mbuf.9 m_copym2.9 m_copym.9 m_free.9 MFREE.9 m_get.9 MGET.9 \ + mbuf.9 m_getclr.9 m_gethdr.9 MGETHDR.9 m_prepend.9 M_PREPEND.9 \ + mbuf.9 m_pulldown.9 m_pullup.9 m_pullup2.9 m_retry.9 m_retryhdr.9 \ + mbuf.9 m_split.9 m_inject.9 m_getptr.9 m_adj.9 m_copyback.9 \ + mbuf.9 m_freem.9 m_reclaim.9 m_copydata.9 m_cat.9 m_devget.9 \ + mbuf.9 m_zero.9 m_apply.9 MEXTALLOC.9 MCLGET.9 MEXTADD.9 \ + mbuf.9 M_ALIGN.9 MH_ALIGN.9 M_READONLY.9 M_LEADINGSPACE.9 \ + mbuf.9 M_TRAILINGSPACE.9 MCHTYPE.9 MLINKS+=pfind.9 pgfind.9 MLINKS+=pool.9 pool_init.9 pool.9 pool_destroy.9 pool.9 pool_get.9 \ pool.9 pool_put.9 pool.9 pool_prime.9 pool.9 pool_sethiwat.9 \ diff --git a/share/man/man9/mbuf.9 b/share/man/man9/mbuf.9 new file mode 100644 index 00000000000..9ca4ce2f4b1 --- /dev/null +++ b/share/man/man9/mbuf.9 @@ -0,0 +1,607 @@ +.\" $OpenBSD: mbuf.9,v 1.3 2001/12/06 10:08:47 jjbg Exp $ +.\" +.\" Copyright (c) 2001 Jean-Jacques Bernard-Gundol <jjbg@openbsd.org> +.\" 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. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. +.\" +.Dd December 4, 2001 +.Dt MBUF 9 +.Os +.Sh NAME +.Nm mbuf +.Nd Kernel memory management for networking protocols +.Sh SYNOPSIS +.Fd #include <sys/mbuf.h> +.Ft struct mbuf * +.Fn m_copym2 "struct mbuf *m" "int off0" "int len" "int wait" +.Ft struct mbuf * +.Fn m_copym "struct mbuf *m" "int off0" "int len" "int wait" +.Ft struct mbuf * +.Fn m_free "struct mbuf *m" +.Fn MFREE "struct mbuf *m" "struct mbuf *n" +.Ft struct mbuf * +.Fn m_get "int nowait" "int type" +.Fn MGET "struct mbuf *m" "int how" "int type" +.Ft struct mbuf * +.Fn m_getclr "int nowait" "int type" +.Ft struct mbuf * +.Fn m_gethdr "int nowait" "int type" +.Fn MGETHDR "struct mbuf *m" "int how" "int type" +.Ft struct mbuf * +.Fn m_prepend "struct mbuf *m" "int len" "int how" +.Fn M_PREPEND "struct mbuf *m" "int plen" "int how" +.Ft struct mbuf * +.Fn m_pulldown "struct mbuf *m" "int off" "int len" "int *offp" +.Ft struct mbuf * +.Fn m_pullup "struct mbuf *n" "int len" +.Ft struct mbuf * +.Fn m_pullup2 "struct mbuf *n" "int len" +.Ft struct mbuf * +.Fn m_retry "int i" "int t" +.Ft struct mbuf * +.Fn m_retryhdr "int i" "int t" +.Ft struct mbuf * +.Fn m_split "struct mbuf *m0" "int len0" "int wait" +.Ft struct mbuf * +.Fn m_inject "struct mbuf *m0" "int len0" "int siz" "int wait" +.Ft struct mbuf * +.Fn m_getptr "struct mbuf *m" "int loc" "int *off" +.Ft void +.Fn m_adj "struct mbuf *mp" "int req_len" +.Ft void +.Fn m_copyback "struct mbuf *m0" "int off" "int len" "caddr_t cp" +.Ft void +.Fn m_freem "struct mbuf *m" +.Ft void +.Fn m_reclaim "void" +.Ft void +.Fn m_copydata "struct mbuf *m" "int off" "int len" "caddr_t cp" +.Ft void +.Fn m_cat "struct mbuf *m" "struct mbuf *n" +.Ft struct mbuf * +.Fn m_devget "char *buf" "int totlen" "int off0" "struct ifnet *ifp" \ +"void (*func)(const void *, void *, size_t)" +.Ft void +.Fn m_zero "struct mbuf *m" +.Ft int +.Fn m_apply "struct mbuf *m" "int off" "int len" \ +"int (*func)(caddr_t, caddr_t, unsigned int)" "caddr_t fstate" +.Fn MEXTALLOC "struct mbuf *m" "int size" "int how" +.Fn MCLGET "struct mbuf *m" "int how" +.Fn MEXTADD "struct mbuf *m" "caddr_t buf" "int type" \ +"void (*free)(caddr_t, u_int, void *)" "void *arg" +.Fn M_ALIGN "struct mbuf *m" "int len" +.Fn MH_ALIGN "struct mbuf *m" "int len" +.Fn M_READONLY "struct mbuf *m" +.Fn M_LEADINGSPACE "struct mbuf *m" +.Fn M_TRAILINGSPACE "struct mbuf *m" +.Fn MCHTYPE "struct mbuf *m" "int type" +.Pp +.Bd -literal +#define MLEN (MSIZE - sizeof(struct m_hdr)) +#define MHLEN (MLEN - sizeof(struct pkthdr)) + +#define MINCLSIZE (MHLEN + 1) +#define M_MAXCOMPRESS (MHLEN / 2) + +#define mtod(m,t) ((t)((m)->m_data)) + +struct m_hdr { + struct mbuf *mh_next; + struct mbuf *mh_nextpkt; + caddr_t mh_data; + u_int mh_len; + short mh_type; + short mh_flags; +}; + +struct pkthdr { + struct ifnet *rcvif; + int len; + void *tdbi; + +}; + +struct m_ext { + caddr_t ext_buf; + void (*ext_free) + __P((struct mbuf *)); + u_int ext_size; + void (*ext_ref) + __P((struct mbuf *)); + void *ext_handle; +}; + +struct mbuf { + struct m_hdr m_hdr; + union { + struct { + struct pkthdr MH_pkthdr; + union { + struct m_ext MH_ext; + char MH_databuf[MHLEN]; + } MH_dat; + } MH; + char M_databuf[MLEN]; + } M_dat; +}; + +union mcluster { + union mcluster *mcl_next; + char mcl_buf[MCLBYTES]; +}; + +#define m_next m_hdr.mh_next +#define m_len m_hdr.mh_len +#define m_data m_hdr.mh_data +#define m_type m_hdr.mh_type +#define m_flags m_hdr.mh_flags +#define m_nextpkt m_hdr.mh_nextpkt +#define m_act m_nextpkt +#define m_pkthdr M_dat.MH.MH_pkthdr +#define m_ext M_dat.MH.MH_dat.MH_ext +#define m_pktdat M_dat.MH.MH_dat.MH_databuf +#define m_dat M_dat.M_databuf +.Ed +.Sh DESCRIPTION +The +.Nm +functions provide a way to manage the memory buffers used by the +Several functions and macros are used to allocate and deallocate mbufs, +but also to get, inject, remove, copy, modify, prepend or append data +inside these mbufs. +The size of an +.Nm +is MSIZE +.Pq defined in Aq Pa machine/param.h . +.Pp +An +.Nm +structure is defined as an +.Fa m_hdr +structure followed by a +union. +The header contains the following elements: +.Bl -tag -width foobarmoocow +.It Fa mh_next +A pointer to the next mbuf in the mbuf chain. +.It Fa mh_nextpkt +A pointer to the next mbuf chain (i.e., packet) in the queue. +.It Fa mh_data +Indicates the address of the beginning of data in the mbuf. +.It Fa mh_type +Indicates the type of data contained in the mbuf (see below). +.It Fa mh_flags +Flags (see below). +.El +.Pp +The +.Fa mh_type +variable can take the following values: +.Bl -tag -compact -offset indent -width XXXXXXXXXXXXXXXXXX +.It Dv MT_FREE +the mbuf should be on the free list. +.It Dv MT_DATA +the data in the mbuf was dynamically allocated. +.It Dv MT_HEADER +the data contains a packet header. +.It Dv MT_SONAME +the data is a socket name. +.It Dv MT_SOOPTS +the data are socket options. +.It Dv MT_FTABLE +the data is a fragment reassembly header. +.It Dv MT_CONTROL +the mbuf contains extra-data protocol message. +.It Dv MT_OOBDATA +the data consists of out-of-banddata. +.El +.Pp +The +.Fa mh_flags +variable can take the following values: +.Bl -tag -compact -offset indent -width XXXXXXXXXXXXXXXXXX +.It Dv M_EXT +mbuf has associated external storage. +.It Dv M_PKTHDR +the mbuf is the first that forms a packet. +.It Dv M_EOR +end of record. +.It Dv M_CLUSTER +the external storage is a cluster. +.It Dv M_PROTO1 +protocol-specific. +.It Dv M_BCAST +packet send/received as link-level broadcast. +.It Dv M_MCAST +packet send/received as link-level multicast. +.It Dv M_CONF +packet was encrypted (ESP-transport). +.It Dv M_AUTH +packet was authenticated (AH). +.It Dv M_COMP +packet was compressed (IPCOMP). +.It Dv M_IPV4_CSUM_OUT +IPv4 checksum needed. +.It Dv M_TCPV4_CSUM_OUT +TCP checksum needed. +.It Dv M_UDPV4_CSUM_OUT +UDP checksum needed. +.It Dv M_IPV4_CSUM_IN_OK +IPv4 checksum verified. +.It Dv M_IPV4_CSUM_IN_BAD +IPv4 checksum bad. +.It Dv M_TCP_CSUM_IN_OK +TCP/IPv4 checksum verified. +.It Dv M_TCP_CSUM_IN_BAD +TCP/IPv4 checksum bad. +.It Dv M_UDP_CSUM_IN_OK +UDP/IPv4 checksum verified. +.It Dv M_UDP_CSUM_IN_BAD +UDP/IPv4 checksum bad. +.It Dv M_ANYCAST6 +received as IPv6 anycast. +.It Dv M_LOOP +for mbuf statistics. +.El +.Pp +An external cluster is used when the data to hold in the mbuf is +large. +The size of an external cluster is MCLBYTES +.Pq also defined in Aq Pa machine/param.h . +A cluster should be used when the size of the data reach MINCLSIZE +(the minimum size to be held by an external cluster). +.Pp +The combination of the M_EXT and M_PKTHDR flags give four types of +mbuf. +When none of these constants are in use, the mbuf is a "normal" +one, where the data part of the mbuf has the following elements: +.Bl -tag -width foobarmoocow +.It Fa m_dat +buffer holding the data (size MLEN). +.El +.Pp +When the M_PKTHDR is set, it means that the data contained in the mbuf +is a packet header. +The data itself is contained in the mbuf (just like the previous case) +but 8 bytes are taken from the data portion to store a packet +header. +The data part has then the following elements: +.Bl -tag -width foobarmoocow +.It Fa m_pkthdr +packet header, containing the length of the data, a pointer to the +interface onwhich the data was received and a generic pointer to a +structure containing information for IPsec processing. +.It Fa m_pktdat +buffer holding the data (size MHLEN). +.El +.Pp +When the M_EXT flag is set, it means that an external storage buffer +is used to hold the data, which is no more stored in the mbuf. +The data part of the mbuf has now the following elements: +.Bl -tag -width foobarmoocow +.It Fa m_pkthdr +a packet header, just like the previous case, but it is empty. +No information is stored here +.It Fa m_ext +a structure containing information about the external storage +buffer. +The information consists of the address of the external buffer, +a pointer to the function used to free the buffer, a pointer to the +arguments of the function, the size of the buffer, the type of the +buffer, and pointers to the previous and next mbufs using this +cluster. +.El +.Pp +When both the M_EXT and M_PKTHDR flags are set, it means that an +external storage buffer is used to store the data and this data +contains a packet header. +The structure used is the same than the previous one except that the +.Fa m_pkthdr +element is not empty, it contains the same information than when +M_PKTHDR is used alone. +.Pp +.Bl -tag -width compact +.It Fn m_copym "struct mbuf *m" "int off0" "int len" "int wait" +Make a copy of an mbuf chain starting at +.Fa off0 +bytes from the beginning +and continuing for +.Fa len +bytes. +The +.Fa wait +parameter can be M_WAIT or +M_DONTWAIT. +It does not copy clusters, it just increases their reference count. +.It Fn m_copym2 "struct mbuf *m" "int off0" "int len" "int wait" +The same as +.Fn m_copym +except that it copies cluster mbufs, where +.Fn m_copym +just increase the reference count of the clusters. +.It Fn m_free "struct mbuf *m" +Free the mbuf pointed to by +.Fa m . +A pointer to the successor of the mbuf, +if it exists, is returned by the function. +.It Fn MFREE "m" "n" +Free the mbuf pointed to by +.Fa m +and use +.Fa n +to point to the next mbuf in +the chain if it exists. +See +.Fn m_free . +.It Fn m_get "int nowait" "int type" +Return a pointer to an mbuf of the type specified. +.It Fn MGET "m" "how" "type" +Return a pointer to an mbuf in +.Fa m +of the type specified. +See +.Fn m_get . +.It Fn m_getclr "int nowait" "int type" +Return a pointer to an mbuf of the type specified, and clear the data +area of the mbuf. +.It Fn m_gethdr "int nowait" "int type" +Return a pointer to an mbuf after initializing it to contain a packet +header. +The type is specified. +.It Fn MGETHDR "m" "int how" "int type" +Return a pointer to an mbuf in m after initializing it to contain a +packet header. +See +.Fn m_gethdr . +.It Fn m_prepend "struct mbuf *m" "int len" "int how" +Allocates a new mbuf and prepend it to the mbuf chain pointed to by +.Fa m . +If +.Fa m +points to an mbuf with a packet header, it is moved to the new +mbuf that has been prepended. +The return value is a pointer on the new mbuf chain. +.It Fn M_PREPEND "m" "plen" "how" +Prepend space of size +.Fa plen +to the mbuf pointed to by +.Fa m . +If a new mbuf must be allocated, +.Fa how +specifies whether to wait or not. +.It Fn m_pulldown "struct mbuf *m" "int off" "int len" "int *offp" +Ensure that the data in the mbuf chain starting at +.Fa off +and ending at +.Fa off+len +will be put in a continuous memory region. +.Fa len +must be smaller or equal than MCLBYTES. +The pointer returned points to an mbuf in the chain and the new offset +for data in this mbuf is +.Fa *offp . +.It Fn m_pullup "struct mbuf *n" "int len" +Ensure that the data in the mbuf chain starting at the beginning of +the chain and ending at +.Fa len +will be put in continuous memory region. +The +.Fa len +argument must be smaller or equal than MHLEN. +.It Fn m_pullup2 "struct mbuf *n" "int len" +Just like +.Fn m_pullup , +ensure that the data starting at the beginning of the mbuf chain and +ending at +.Fa len +will be put in continuous memory region. +The +.Fa len +argument can be up to MCLBYTES. +.Fn m_pullup2 +will simply call +.Fn m_pullup +if +.Fa len +is smaller or equal to MHLEN. +.It Fn m_retry "int i" "int t" +Used when +.Fn MGET +fails. +.Fn m_retry +asks protocols to free memory space and re-attempts to allocate an mbuf. +.It Fn m_retryhdr "int i" "int t" +Same as +.Fn m_retry +except it retries a failed +.Fn MRETRYHDR . +.It Fn m_split "struct mbuf *m0" "int len0" "int wait" +Attempts to split an mbuf chain in 2 pieces, returning a pointer on +the tail (which is made of the previous mbuf chain but the first +.Fa len0 +bytes). +.It Fn m_inject "struct mbuf *m0" "int len0" "int siz" "int wait" +Injects a new mbuf chain of length +.Fa siz +in the mbuf chain pointed to by +.Fa m0 +at position +.Fa len0 . +If there is enough space for an object of size +.Fa siz +in the appropriate location, no memory will be allocated. +On failure, the function returns NULL (the mbuf is left untouched) and +on success, a pointer to the first injected mbuf is returned. +.It Fn m_getptr "struct mbuf *m" "int loc" "int *off" +Returns a pointer to the mbuf containing the data located at +.Fa loc +bytes of the beginning. +The offset in the new mbuf is pointed to by +.Fa off . +.It Fn m_adj "struct mbuf *mp" "int req_len" +Trims +.Fa req_len +bytes of data from the mbuf chain pointed to by +.Fa mp . +If +.Fa req_len +is positive, the data will be trimmed from the head of the mbuf chain +and if it is negative, it will be trimmed from the tail of the mbuf +chain. +.It Fn m_copyback "struct mbuf *m0" "int off" "int len" "caddr_t cp" +Copy data from a buffer back into the mbuf chain pointed to by +.Fa m0 +starting at +.Fa off +bytes from the beginning and extending the mbuf chain if +necessary. +The mbufs need to be initialized properly, including the setting of +.Fa m_len . +.It Fn m_freem "struct mbuf *m" +Free the mbuf chain pointed to by +.Fa m . +.It Fn m_reclaim "void" +Ask protocols to free unused memory space. +.It Fn m_copydata "struct mbuf *m" "int off" "int len" "caddr_t cp" +Copy data from the mbuf chain pointed to by +.Fa m +starting at +.Fa off +bytes from the beginning and continuing for +.Fa len +bytes into the buffer pointed to by +.Fa cp . +.It Fn m_cat "struct mbuf *m" "struct mbuf *n" +Concatenate the mbuf chain pointed to by +.Fa n +to the mbuf chain pointed to by +.Fa m . +The mbuf chains must be of the same type. +.It Fn m_devget "char *buf" "int totlen" "int off0" "struct ifnet *ifp" \ +"void (*func)(const void *, void *, size_t)" +Copy +.Fa totlen +bytes of data from device local memory pointed to by +.Fa buf +using the function +.Fa func . +The data is copied into an mbuf chain and a pointer to the head of it +is returned. +If +.Fa off0 +is non-zero, it means the packet is trailer-encapsulated and +.Fa off0 +bytes plus the type and length fields will be skipped before doing the +copy. +.It Fn m_zero "struct mbuf *m" +Zeroize the data part of the mbufs in the mbuf chain pointed to by +.Fa m +.It Fn m_apply "struct mbuf *m" "int off" "int len" \ +"int (*func)(caddr_t, caddr_t, unsigned int)" "caddr_t fstate" +Apply the function +.Fa func +to the data in the mbuf chain pointed to by +.Fa m +starting at +.Fa off +bytes from the beginning and continuing for +.Fa len +bytes. +.It Fn mtod "struct mbuf *m" "datatype" +Return a pointer to the data contained in the specified mbuf +.Fa m +casted to +.Fa datatype . +.It Fn MCLGET "struct mbuf *m" "int how" +Allocate and add an mbuf cluster to the mbuf pointed to by +.Fa m . +On success, the flag M_EXT is set in the mbuf. +.It Fn MEXTALLOC "struct mbuf *m" "int size" "int how" +Allocate external storage of size +.Fa size +and add it to the mbuf pointed to by +.Fa m . +On success, the flag M_EXT is set in the mbuf. +.It Fn MEXTADD "struct mbuf *m" "caddr_t buf" "int type" \ +"void (*free)(caddr_t, u_int, void *)" "void *arg" +Add pre-allocated storage to the mbuf pointed to by +.Fa m . +On success, the flag M_EXT is set in the mbuf. +.It Fn M_ALIGN "m" "len" +Set the +.Fa m_data +pointer of the newly allocated mbuf with +.Fn m_get +or +.Fn MGET +pointed to by +.Fa m +to an object of the specified size +.Fa len +at the end of the mbuf, longword aligned. +.It Fn MH_ALIGN "m" "len" +Same as +.Fn M_ALIGN +except it is for an mbuf allocated with +.Fn m_gethdr +or +.Fn MGETHDR . +.It Fn M_READONLY "m" +Check if the data of the mbuf pointed to by +.Fa m +is read-only. +This is true for non-cluster external storage and for clusters that +are being referenced by more than one mbuf. +.It Fn M_LEADINGSPACE "m" +Compute the amount of space available before the current start of data +in the mbuf pointed to by +.Fa m . +.It Fn M_TRAILINGSPACE "m" +Compute the amount of space available after the end of data in the +mbuf pointed to by +.Fa m . +.It Fn MCHTYPE "m" "type" +Change the type of the mbuf pointed to by +.Fa m +to +.Fa type . +.El +.Sh SEE ALSO +.Xr netstat 1 , +.Xr mbuf_tags 9 , +.Pa /usr/share/doc/smm/18.net. +.Rs +.%A Jun-Ichiro Hagino +.%T "Mbuf issues in 4.4BSD IPv6/IPsec support (experiences from KAME IPv6/IPsec implementation)" +.%B "Proceedings of the freenix track: 2000 USENIX annual technical conference" +.%D June 2000 +.Re +.Sh CODE REFERENCES +The mbuf management functions are implemented in the files +.Pa sys/kern/uipc_mbuf.c +and +.Pa sys/kern/uipc_mbuf2.c . +The function prototypes and the macros are located in +.Pa sys/sys/mbuf.h . |