2000-02-03 Roland McGrath <roland@baalperazim.frob.com>

	Complete overhaul of pfinet based on the IPv4 networking code from the
	Linux 2.2.12 kernel sources.  This page describes a single unified set
	of interdependent changes, but there are so many changes that I have
	broken up the log entry into paragraphs based on rough topical
	divisions of the work involved.

	Subset of verbatim Linux 2.2.12 sources imported on a vendor branch.
	* linux-src: New directory, see README for details.
	* README: New file, describes linux-src layout and procedures for
	tracking Linux source updates.

	Light modifications to linux-src files to avoid really bending over
	backwards with the glue macros.  All modifications to files in
	linux-src are conditionalized by #ifdef _HURD_.
	* linux-src/include/linux/net.h [_HURD_] (struct socket): New members
	refcnt and identity; elide members fasync_list, file.
	* linux-src/include/linux/rtnetlink.h [! CONFIG_RTNETLINK]
	(rtnl_shlock, rtnl_shunlock) [! _HURD_]: Conditionalize contents on
	this, making these no-ops #ifdef _HURD_.
	* linux-src/net/core/dev.c [_HURD_] (dev_ioctl): Don't define the
	function, instead #define it to 0.
	* linux-src/net/ipv4/af_inet.c [_HURD_] (inet_ioctl): Likewise.
	* linux-src/net/ipv4/arp.c [_HURD_] (arp_ioctl): Likewise.
	* linux-src/net/ipv4/udp.c [_HURD_] (udp_ioctl): Likewise.
	* linux-src/net/ipv4/tcp.c [_HURD_] (tcp_ioctl): Likewise.
	[_HURD_] (tcp_tiocinq): New function, TIOCINQ code from tcp_ioctl.
	* linux-src/net/ipv4/devinet.c [_HURD_] (devinet_ioctl): Don't define
	the function, instead #define it to 0.
	[_HURD_] (configure_device): New function, cobbled from SIOCSIFADDR
	and SIOCSIFNETMASK code from devinet_ioctl.

	* glue-include/asm, glue-include/linux: New directories.
	These contain glue kludge headers that replace all of the
	Linux <asm/*.h> headers except checksum.h, and several of
	the Linux <linux/*.h> headers (the remainder come from
	linux-src/include/linux and are mostly unmodified).
	* glue-include/asm/atomic.h: New file, glue replacement header.
	* glue-include/asm/bitops.h: New file, glue replacement header.
	* glue-include/asm/byteorder.h: New file, glue replacement header.
	* glue-include/asm/checksum.h: New file, glue replacement header.
	* glue-include/asm/errno.h: New file, glue replacement header.
	* glue-include/asm/hardirq.h: New file, glue replacement header.
	* glue-include/asm/init.h: New file, glue replacement header.
	* glue-include/asm/segment.h: New file, glue replacement header.
	* glue-include/asm/spinlock.h: New file, glue replacement header.
	* glue-include/asm/system.h: New file, glue replacement header.
	* glue-include/asm/types.h: New file, glue replacement header.
	* glue-include/asm/uaccess.h: New file, glue replacement header.
	* glue-include/linux/autoconf.h: New file, glue replacement header.
	* glue-include/linux/binfmts.h: New file, glue replacement header.
	* glue-include/linux/config.h: New file, glue replacement header.
	* glue-include/linux/errno.h: New file, glue replacement header.
	* glue-include/linux/fcntl.h: New file, glue replacement header.
	* glue-include/linux/fs.h: New file, glue replacement header.
	* glue-include/linux/in.h: New file, glue replacement header.
	* glue-include/linux/in6.h: New file, glue replacement header.
	* glue-include/linux/interrupt.h: New file, glue replacement header.
	* glue-include/linux/ioctl.h: New file, glue replacement header.
	* glue-include/linux/ipv6.h: New file, glue replacement header.
	* glue-include/linux/kernel.h: New file, glue replacement header.
	* glue-include/linux/limits.h: New file, glue replacement header.
	* glue-include/linux/major.h: New file, glue replacement header.
	* glue-include/linux/malloc.h: New file, glue replacement header.
	* glue-include/linux/mm.h: New file, glue replacement header.
	* glue-include/linux/param.h: New file, glue replacement header.
	* glue-include/linux/personality.h: New file, glue replacement header.
	* glue-include/linux/poll.h: New file, glue replacement header.
	* glue-include/linux/proc_fs.h: New file, glue replacement header.
	* glue-include/linux/sched.h: New file, glue replacement header.
	* glue-include/linux/slab.h: New file, glue replacement header.
	* glue-include/linux/socket.h: New file, glue replacement header.
	* glue-include/linux/sockios.h: New file, glue replacement header.
	* glue-include/linux/stat.h: New file, glue replacement header.
	* glue-include/linux/string.h: New file, glue replacement header.
	* glue-include/linux/termios.h: New file, glue replacement header.
	* glue-include/linux/time.h: New file, glue replacement header.
	* glue-include/linux/timer.h: New file, glue replacement header.
	* glue-include/linux/timex.h: New file, glue replacement header.
	* glue-include/linux/types.h: New file, glue replacement header.
	* glue-include/linux/un.h: New file, glue replacement header.
	* glue-include/linux/version.h: New file, glue replacement header.
	* glue-include/linux/wait.h: New file, glue replacement header.

	* kmem_cache.c: New file.  Glue code replaces Linux kmem_cache_t et al.
	* stubs.c: New file.  No-op functions and stub variables for a few
	things the Linux networking code needs to link.

	* Makefile (core-srcs, arch-lib-srcs, ethernet-srcs, ipv4-srcs): New
	variables, listing sources used from linux-src subdirectories.
	(LINUXSRCS): Define using those.
	(SRCS): Remove devices.c; add kmem_cache.c, stubs.c.
	(UNUSEDSRC): Variable removed.
	(vpath %.c): Remove vpath for $(srcdir)/linux-inet directory.
	Add vpaths for $(srcdir)/linux-src subdirectories.
	(CPPFLAGS): Add -D_HURD_SYSTYPE defining it to $(asm_syntax) as a
	double-quoted string.  Add -I's for glue-include and linux-src/include.

	* pfinet.h: Include <sys/socket.h>, and not <linux/netdevice.h>.
	(master_device): Remove decl.
	(global_lock, packet_queue_lock): Remove common defns.
	(global_lock, net_bh_lock): Declare them as externs.
	(struct sockaddr): Remove len member, make address member just a
	struct sockaddr rather than a 0-length array.
	(setup_loopback_device, become_task_protid, become_task): Remove decls.
	(ethernet_initialize): Declare it.
	(input_work_thread): Remove decl.
	(net_bh_thread): Declare it.
	(tcp_readable): Remove decl.
	(tcp_tiocinq): Declare it.

	* config.h: Rewritten based on Linux 2.2.12 set of CONFIG_* options.
	(CONFIG_NET, CONFIG_INET, CONFIG_SKB_LARGE): These are the only
	Linux config options we set.
	(CONFIG_IP_NOSIOCRT): New macro (not a proper config option, but
	used conveniently in the code).
	* ethernet.c (ethernet_set_multi): Take only one parameter.
	Remove assert, since we always get passed IGMP_ALL_HOSTS.
	(ethernet_thread): Make static.
	(ethernet_demuxer): Use __mutex_lock in place of mutex_lock, so as to
	get cthreads instead of linux/spinlock.h glue macros.  Lock
	net_bh_lock instead of global_lock.  Set SKB->protocol with
	eth_type_trans before calling netif_rx.
	(ethernet_initialize): New function, one-time initialization broken
	out of ethernet_open.
	(ethernet_open): Ports setup moved to ethernet_initialize.
	Don't use `errno' to avoid glue conflicts.
	Use get_privileged_ports here to get the master device port, and
	deallocate it after calling device_open.
	(ethernet_xmit): Use assert_perror.  Only one arg to dev_kfree_skb now.
	(setup_ethernet_device): Change initializations for structure changes.
	Call dev_init_buffers and register_netdevice on the device.
	* timer-emul.c (all functions): Use __mutex_lock instead of mutex_lock.
	Adjust for renaming of `prevp' member to `prev' in struct timer_list.
	(mod_timer): New function.
	* socket.c (proto_ops): Variable removed.
	(net_families): New variable replaces it.
	(sock_register): Rewritten for new calling convention, set
	net_families rather than proto_ops.
	(make_sock_user, clean_socketport, sock_alloc, sock_release):
	Functions moved here from misc.c.
	* sched.c (packet_queue_lock): Variable removed.
	(net_bh_lock, net_bh_wakeup): New variables.
	(current): Variable removed (now a macro in the glue headers).
	(interruptible_sleep_on, wake_up_interruptible): Functions removed.
	They are replaced by inlines in the glue headers.
	(become_task, become_task_protid): Functions removed; they are
	replaced by macros in glue-include/linux/sched.h.
	(net_bh_worker): New function.
	* loopback.c: Completely rewritten, mostly copied from linux-2.2.12's
	drivers/net/loopback.c source file.

	* io-ops.c (all functions): Use __mutex_lock in place of mutex_lock.
	(S_io_write): Call ops->sendmsg instead of ops->write,
	which no longer exists.  If O_NONBLOCK is set, set MSG_DONTWAIT in
	msg_flags.
	(S_io_read): Call ops->recvmsg instead of ops->read,
	which no longer exists  If O_NONBLOCK is set, pass MSG_DONTWAIT.
	(S_io_readable): Use USER->sock->data in place of USER->sock->sk.
	For SOCK_STREAM and SOCK_SEQPACKET types, call tcp_tiocinq.
	(S_io_set_all_openmodes, S_io_get_openmodes, S_io_set_some_openmodes,
	S_io_clear_some_openmodes): Member USER->sock->userflags is now
	renamed USER->sock->flags.
	(S_io_select): Completely rewritten using ops->poll.
	(select_wait): Function removed.
	(S_io_stat): Set st_mode to reflect S_IFSOCK.
	* socket-ops.c (all functions): Use __mutex_lock instead of mutex_lock.
	(S_socket_create): Don't set SOCK->ops or call SOCK->ops->create.
	Instead, call net_families[PF_INET]->create.
	(S_socket_listen): Remove extra checks; just call ops->listen.
	(S_socket_accept): Remove extra checks before ops->accept call.
	Avoid use of goto.
	(S_socket_connect): Remove extra checks; just call ops->connect.
	(S_socket_bind): Adjust for struct sock_addr changes.
	(S_socket_create_address): Likewise.
	(S_socket_whatis_address): Likewise.
	(S_socket_connect2): Don't diddle data structures after
	ops->socketpair call.
	(S_socket_getopt): Use sock_getsockopt if LEVEL is SOL_SOCKET.
	Accept any data size, not just sizeof (int).
	(S_socket_setopt): Use sock_setsockopt if LEVEL is SOL_SOCKET.
	(S_socket_send): Always use ops->sendmsg instead of ops->send or
	ops->sendto, which no longer exist.  If O_NONBLOCK is set, set
	MSG_DONTWAIT in msg_flags.
	(S_socket_recv): Always use ops->recvmsg instead of ops->recv, which
	no longer exists.  If O_NONBLOCK is set, set MSG_DONTWAIT in flags.
	Check for error from S_socket_create_address.

	* main.c (find_device): Don't try to set ether_dev.pa_mask (it's gone).
	(main): Don't call init_devices.  Call ethernet_initialize.
	Start net_bh_worker instead of input_work_thread.  Don't call
	setup_loopback_device.  Instead, take global_lock, do prepare_current,
	and then call sk_init, skb_init, inet_proto_init, and net_dev_init.
	Keep global_lock held while calling argp_parse.
	Call arrange_shutdown_notification only after all that.
	Fix error call for "contacting parent" to pass ERR instead of errno.
	* options.c (ADDR): #undef before defining macro.
	(parse_opt): #if 0 out EDESTADDRREQ check (I don't understand it).
	To apply settings, call configure_devices.
	(ADD_ADDR_OPT): #if 0 --address and --netmask options.  Needs fixed.
	* misc.c (make_sock_user, clean_socketport, sock_alloc, sock_release):
	Functions moved to socket.c.
	(sock_release_peer): Function removed.
	(make_sockaddr_port): Use struct sockaddr_storage to size buffer.
	Fix size calculation for new struct sock_addr layout.
	Initialize sa_family and sa_len of new struct sock_addr.

	Remove the old Linux (2.0.??) network stack and the glue code for it.
	* linux-inet, asm, linux: Directories and all files removed.
	Some of the new files in glue-include came from the old glue headers
	in the asm and linux directories, but most were substantially modified.
	* devices.c: File removed.  The equivalent glue is now elsewhere.

1 files changed, 0 insertions, 257 deletions

diff --git a/pfinet/linux-inet/proc.c b/pfinet/linux-inet/proc.c
deleted file mode 100644
index aec473a2..00000000
--- a/pfinet/linux-inet/proc.c
+++ /dev/null
@@ -1,257 +0,0 @@
-/*
- * INET		An implementation of the TCP/IP protocol suite for the LINUX
- *		operating system.  INET is implemented using the  BSD Socket
- *		interface as the means of communication with the user level.
- *
- *		This file implements the various access functions for the
- *		PROC file system.  It is mainly used for debugging and
- *		statistics.
- *
- * Version:	@(#)proc.c	1.0.5	05/27/93
- *
- * Authors:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
- *		Gerald J. Heim, <heim@peanuts.informatik.uni-tuebingen.de>
- *		Fred Baumgarten, <dc6iq@insu1.etec.uni-karlsruhe.de>
- *		Erik Schoenfelder, <schoenfr@ibr.cs.tu-bs.de>
- *
- * Fixes:
- *		Alan Cox	:	UDP sockets show the rxqueue/txqueue
- *					using hint flag for the netinfo.
- *	Pauline Middelink	:	identd support
- *		Alan Cox	:	Make /proc safer.
- *	Erik Schoenfelder	:	/proc/net/snmp
- *		Alan Cox	:	Handle dead sockets properly.
- *
- *		This program is free software; you can redistribute it and/or
- *		modify it under the terms of the GNU General Public License
- *		as published by the Free Software Foundation; either version
- *		2 of the License, or (at your option) any later version.
- */
-#include <asm/system.h>
-#include <linux/autoconf.h>
-#include <linux/sched.h>
-#include <linux/socket.h>
-#include <linux/net.h>
-#include <linux/un.h>
-#include <linux/in.h>
-#include <linux/param.h>
-#include <linux/inet.h>
-#include <linux/netdevice.h>
-#include "ip.h"
-#include "icmp.h"
-#include "protocol.h"
-#include "tcp.h"
-#include "udp.h"
-#include <linux/skbuff.h>
-#include "sock.h"
-#include "raw.h"
-
-/*
- * Get__netinfo returns the length of that string.
- *
- * KNOWN BUGS
- *  As in get_unix_netinfo, the buffer might be too small. If this
- *  happens, get__netinfo returns only part of the available infos.
- */
-static int
-get__netinfo(struct proto *pro, char *buffer, int format, char **start, off_t offset, int length)
-{
-	struct sock **s_array;
-	struct sock *sp;
-	int i;
-	int timer_active;
-	unsigned long  dest, src;
-	unsigned short destp, srcp;
-	int len=0;
-	off_t pos=0;
-	off_t begin=0;
-  
-	s_array = pro->sock_array;
-	len+=sprintf(buffer, "sl  local_address rem_address   st tx_queue rx_queue tr tm->when uid\n");
-/*
- *	This was very pretty but didn't work when a socket is destroyed at the wrong moment
- *	(eg a syn recv socket getting a reset), or a memory timer destroy. Instead of playing
- *	with timers we just concede defeat and cli().
- */
-	for(i = 0; i < SOCK_ARRAY_SIZE; i++) 
-	{
-	  	cli();
-		sp = s_array[i];
-		while(sp != NULL) 
-		{
-			dest  = sp->daddr;
-			src   = sp->saddr;
-			destp = sp->dummy_th.dest;
-			srcp  = sp->dummy_th.source;
-
-			/* Since we are Little Endian we need to swap the bytes :-( */
-			destp = ntohs(destp);
-			srcp  = ntohs(srcp);
-			timer_active = del_timer(&sp->timer);
-			if (!timer_active)
-				sp->timer.expires = 0;
-			len+=sprintf(buffer+len, "%2d: %08lX:%04X %08lX:%04X %02X %08lX:%08lX %02X:%08lX %08X %d %d\n",
-				i, src, srcp, dest, destp, sp->state, 
-				format==0?sp->write_seq-sp->rcv_ack_seq:sp->rmem_alloc, 
-				format==0?sp->acked_seq-sp->copied_seq:sp->wmem_alloc,
-				timer_active, sp->timer.expires, (unsigned) sp->retransmits,
-				sp->socket?SOCK_INODE(sp->socket)->i_uid:0,
-				timer_active?sp->timeout:0);
-			if (timer_active)
-				add_timer(&sp->timer);
-			/*
-			 * All sockets with (port mod SOCK_ARRAY_SIZE) = i
-			 * are kept in sock_array[i], so we must follow the
-			 * 'next' link to get them all.
-			 */
-			sp = sp->next;
-			pos=begin+len;
-			if(pos<offset)
-			{
-				len=0;
-				begin=pos;
-			}
-			if(pos>offset+length)
-				break;
-		}
-		sti();	/* We only turn interrupts back on for a moment, but because the interrupt queues anything built up
-			   before this will clear before we jump back and cli, so it's not as bad as it looks */
-		if(pos>offset+length)
-			break;
-	}
-	*start=buffer+(offset-begin);
-	len-=(offset-begin);
-	if(len>length)
-	  	len=length;
-	return len;
-} 
-
-
-int tcp_get_info(char *buffer, char **start, off_t offset, int length)
-{
-	return get__netinfo(&tcp_prot, buffer,0, start, offset, length);
-}
-
-
-int udp_get_info(char *buffer, char **start, off_t offset, int length)
-{
-	return get__netinfo(&udp_prot, buffer,1, start, offset, length);
-}
-
-
-int raw_get_info(char *buffer, char **start, off_t offset, int length)
-{
-	return get__netinfo(&raw_prot, buffer,1, start, offset, length);
-}
-
-
-/*
- *	Report socket allocation statistics [mea@utu.fi]
- */
-int afinet_get_info(char *buffer, char **start, off_t offset, int length)
-{
-	/* From  net/socket.c  */
-	extern int socket_get_info(char *, char **, off_t, int);
-#ifndef _HURD_
-	extern struct proto packet_prot;
-	int len  = socket_get_info(buffer,start,offset,length);
-#else
-	int len = 0;
-#endif
-
-
-	len += sprintf(buffer+len,"SOCK_ARRAY_SIZE=%d\n",SOCK_ARRAY_SIZE);
-	len += sprintf(buffer+len,"TCP: inuse %d highest %d\n",
-		       tcp_prot.inuse, tcp_prot.highestinuse);
-	len += sprintf(buffer+len,"UDP: inuse %d highest %d\n",
-		       udp_prot.inuse, udp_prot.highestinuse);
-	len += sprintf(buffer+len,"RAW: inuse %d highest %d\n",
-		       raw_prot.inuse, raw_prot.highestinuse);
-#ifndef _HURD_
-	len += sprintf(buffer+len,"PAC: inuse %d highest %d\n",
-		       packet_prot.inuse, packet_prot.highestinuse);
-#endif
-	*start = buffer + offset;
-	len -= offset;
-	if (len > length)
-		len = length;
-	return len;
-}
-
-
-/* 
- *	Called from the PROCfs module. This outputs /proc/net/snmp.
- */
- 
-int snmp_get_info(char *buffer, char **start, off_t offset, int length)
-{
-	extern struct tcp_mib tcp_statistics;
-	extern struct udp_mib udp_statistics;
-	int len;
-/*
-  extern unsigned long tcp_rx_miss, tcp_rx_hit1,tcp_rx_hit2;
-*/
-
-	len = sprintf (buffer,
-		"Ip: Forwarding DefaultTTL InReceives InHdrErrors InAddrErrors ForwDatagrams InUnknownProtos InDiscards InDelivers OutRequests OutDiscards OutNoRoutes ReasmTimeout ReasmReqds ReasmOKs ReasmFails FragOKs FragFails FragCreates\n"
-		"Ip: %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
-		    ip_statistics.IpForwarding, ip_statistics.IpDefaultTTL, 
-		    ip_statistics.IpInReceives, ip_statistics.IpInHdrErrors, 
-		    ip_statistics.IpInAddrErrors, ip_statistics.IpForwDatagrams, 
-		    ip_statistics.IpInUnknownProtos, ip_statistics.IpInDiscards, 
-		    ip_statistics.IpInDelivers, ip_statistics.IpOutRequests, 
-		    ip_statistics.IpOutDiscards, ip_statistics.IpOutNoRoutes, 
-		    ip_statistics.IpReasmTimeout, ip_statistics.IpReasmReqds, 
-		    ip_statistics.IpReasmOKs, ip_statistics.IpReasmFails, 
-		    ip_statistics.IpFragOKs, ip_statistics.IpFragFails, 
-		    ip_statistics.IpFragCreates);
-		    		
-	len += sprintf (buffer + len,
-		"Icmp: InMsgs InErrors InDestUnreachs InTimeExcds InParmProbs InSrcQuenchs InRedirects InEchos InEchoReps InTimestamps InTimestampReps InAddrMasks InAddrMaskReps OutMsgs OutErrors OutDestUnreachs OutTimeExcds OutParmProbs OutSrcQuenchs OutRedirects OutEchos OutEchoReps OutTimestamps OutTimestampReps OutAddrMasks OutAddrMaskReps\n"
-		"Icmp: %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
-		    icmp_statistics.IcmpInMsgs, icmp_statistics.IcmpInErrors,
-		    icmp_statistics.IcmpInDestUnreachs, icmp_statistics.IcmpInTimeExcds,
-		    icmp_statistics.IcmpInParmProbs, icmp_statistics.IcmpInSrcQuenchs,
-		    icmp_statistics.IcmpInRedirects, icmp_statistics.IcmpInEchos,
-		    icmp_statistics.IcmpInEchoReps, icmp_statistics.IcmpInTimestamps,
-		    icmp_statistics.IcmpInTimestampReps, icmp_statistics.IcmpInAddrMasks,
-		    icmp_statistics.IcmpInAddrMaskReps, icmp_statistics.IcmpOutMsgs,
-		    icmp_statistics.IcmpOutErrors, icmp_statistics.IcmpOutDestUnreachs,
-		    icmp_statistics.IcmpOutTimeExcds, icmp_statistics.IcmpOutParmProbs,
-		    icmp_statistics.IcmpOutSrcQuenchs, icmp_statistics.IcmpOutRedirects,
-		    icmp_statistics.IcmpOutEchos, icmp_statistics.IcmpOutEchoReps,
-		    icmp_statistics.IcmpOutTimestamps, icmp_statistics.IcmpOutTimestampReps,
-		    icmp_statistics.IcmpOutAddrMasks, icmp_statistics.IcmpOutAddrMaskReps);
-	
-	len += sprintf (buffer + len,
-		"Tcp: RtoAlgorithm RtoMin RtoMax MaxConn ActiveOpens PassiveOpens AttemptFails EstabResets CurrEstab InSegs OutSegs RetransSegs\n"
-		"Tcp: %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
-		    tcp_statistics.TcpRtoAlgorithm, tcp_statistics.TcpRtoMin,
-		    tcp_statistics.TcpRtoMax, tcp_statistics.TcpMaxConn,
-		    tcp_statistics.TcpActiveOpens, tcp_statistics.TcpPassiveOpens,
-		    tcp_statistics.TcpAttemptFails, tcp_statistics.TcpEstabResets,
-		    tcp_statistics.TcpCurrEstab, tcp_statistics.TcpInSegs,
-		    tcp_statistics.TcpOutSegs, tcp_statistics.TcpRetransSegs);
-		
-	len += sprintf (buffer + len,
-		"Udp: InDatagrams NoPorts InErrors OutDatagrams\nUdp: %lu %lu %lu %lu\n",
-		    udp_statistics.UdpInDatagrams, udp_statistics.UdpNoPorts,
-		    udp_statistics.UdpInErrors, udp_statistics.UdpOutDatagrams);	    
-/*	
-	  len += sprintf( buffer + len,
-	  	"TCP fast path RX:  H2: %ul H1: %ul L: %ul\n",
-	  		tcp_rx_hit2,tcp_rx_hit1,tcp_rx_miss);
-*/
-	
-	if (offset >= len)
-	{
-		*start = buffer;
-		return 0;
-	}
-	*start = buffer + offset;
-	len -= offset;
-	if (len > length)
-		len = length;
-	return len;
-}
-