SPARC/Solaris 8下快速终结TCP有限状态机的TIME_WAIT状态

　　1987年10月1日(可真够早的)cdjohns@nswc-g.arpa提供了一个shell script，用于

　　SunOS 4.x系统下快速终结TCP有限状态机的TIME_WAIT状态。很奇怪，这个脚本并未

　　得到人们的足够重视并广泛流传，直到SunOS 4.x退出历史舞台，它也就销声匿迹了。

　　昨天被backend从故纸堆里翻了出来，我们就趁机移植到SPARC/Solaris 8下来。

　　/usr/include/netinet里的文件多是为用户空间编程准备的，/usr/include/inet里

　　的文件多是为内核空间编程准备的。下面内容取自SPARC/Solaris 8

　　--------------------------------------------------------------------------

　　* /usr/include/inet/tcp.h

　　* TCP states

　　#define TCPS_CLOSED -6

　　#define TCPS_IDLE -5 /* idle (opened， but not bound) */

　　#define TCPS_BOUND -4 /* bound， ready to connect or accept */

　　#define TCPS_LISTEN -3 /* listening for connection */

　　#define TCPS_SYN_SENT -2 /* active， have sent syn */

　　#define TCPS_SYN_RCVD -1 /* have received syn (and sent ours) */

　　* states < TCPS_ESTABLISHED are those where connections not established

　　#define TCPS_ESTABLISHED 0 /* established */

　　#define TCPS_CLOSE_WAIT 1 /* rcvd fin， waiting for close */

　　* states > TCPS_CLOSE_WAIT are those where user has closed

　　#define TCPS_FIN_WAIT_1 2 /* have closed and sent fin */

　　#define TCPS_CLOSING 3 /* closed， xchd FIN， await FIN ACK */

　　#define TCPS_LAST_ACK 4 /* had fin and close; await FIN ACK */

　　* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN

　　#define TCPS_FIN_WAIT_2 5 /* have closed， fin is acked */

　　#define TCPS_TIME_WAIT 6 /* in 2*msl quiet wait after close */

　　#if (defined(_KERNEL) || defined(_KMEMUSER))

　　* If the information represented by the field is required even in the

　　* TIME_WAIT state， it must be part of tcpb_t. Otherwise it must be part

　　* of tcp_t. In other words， the tcp_t captures the information that is

　　* not required， after a connection has entered the TIME_WAIT state.

　　typedef struct tcp_base_s

　　{

　　struct tcp_base_s *tcpb_bind_hash; /* Bind hash chain */

　　struct tcp_base_s **tcpb_ptpbhn; /* Pointer to previous bind hash next. */

　　struct tcp_base_s *tcpb_conn_hash; /* Connect hash chain */

　　struct tcp_base_s **tcpb_ptpchn; /* Pointer to previous conn hash next. */

　　struct tcp_base_s *tcpb_time_wait_next; /* Pointer to next T/W block */

　　struct tcp_base_s *tcpb_time_wait_prev; /* Pointer to previous T/W next */

　　* /usr/include/sys/types.h

　　* typedef long clock_t;

　　* offset: 8 * 6 -> 48 -> 0x30，clock_t占8个字节(64-bit kernel mode)

　　clock_t tcpb_time_wait_expire; /* time in hz when t/w expires */

　　clock_t tcpb_last_rcv_lbolt; /* lbolt on last packet， used for PAWS */

　　* offset: 0x40

　　int32_t tcpb_state;

　　int32_t tcpb_rcv_ws; /* My window scale power */

　　int32_t tcpb_snd_ws; /* Sender's window scale power */

　　uint32_t tcpb_ts_recent; /* Timestamp of earliest unacked */

　　* data segment

　　* offset: 0x50

　　clock_t tcpb_rto; /* Round trip timeout */

　　uint32_t tcpb_snd_ts_ok : 1，

　　tcpb_snd_ws_ok : 1，

　　tcpb_is_secure : 1，

　　tcpb_reuseaddr : 1， /* SO_REUSEADDR "socket" option. */

　　tcpb_exclbind : 1， /* ``exclusive'' binding */

　　tcpb_junk_fill_thru_bit_31 : 27;

　　* offset: 0x5c

　　uint32_t tcpb_snxt; /* Senders next seq num */

　　uint32_t tcpb_swnd; /* Senders window (relative to suna) */

　　uint32_t tcpb_mss; /* Max segment size */

　　uint32_t tcpb_iss; /* Initial send seq num */

　　* offset: 0x6c

　　uint32_t tcpb_rnxt; /* Seq we expect to recv next */

　　uint32_t tcpb_rwnd; /* Current receive window */

　　* /usr/include/sys/mutex.h

　　* 无论64-bit还是32-bit kernel mode，kmutex_t都占8字节空间，这里需要对

　　* 齐在数据类型自然连界上，0x6c + 8 -> 0x74不在kmutex_t自然边界上，继

　　* 续后移4个字节

　　* offset: 0x78

　　kmutex_t tcpb_reflock; /* Protects tcp_refcnt */

　　* offset: 0x80

　　ushort_t tcpb_refcnt; /* Number of pending upstream msg */

　　union

　　{

　　struct

　　{

　　uchar_t v4_ttl; /* Dup of tcp_ipha.iph_type_of_service */

　　uchar_t v4_tos; /* Dup of tcp_ipha.iph_ttl */

　　} v4_hdr_info;

　　struct

　　{

　　* 对齐在uint_t的自然边界上

　　* offset: 0x84

　　uint_t v6_vcf; /* Dup of tcp_ip6h.ip6h_vcf */

　　* offset: 0x88

　　uchar_t v6_hops; /* Dup of tcp_ip6h.ip6h_hops */

　　} v6_hdr_info;

　　} tcpb_hdr_info;

　　#define tcpb_ttl tcpb_hdr_info.v4_hdr_info.v4_ttl

　　#define tcpb_tos tcpb_hdr_info.v4_hdr_info.v4_tos

　　#define tcpb_ip6_vcf tcpb_hdr_info.v6_hdr_info.v6_vcf

　　#define tcpb_ip6_hops tcpb_hdr_info.v6_hdr_info.v6_hops

　　* offset: 0x8c，先是远端地址，后是本地地址

　　* /usr/include/netinet/in.h

　　* in6_addr_t长16字节，在内核空间里这个结构对齐在uint32_t的自然边界上

　　in6_addr_t tcpb_remote_v6; /* true remote address - needed for */

　　/* source routing. */

　　in6_addr_t tcpb_bound_source_v6; /* IP address in bind_req */

　　* offset: 0xac

　　in6_addr_t tcpb_ip_src_v6; /* same as tcp_iph.iph_src. */

　　#ifdef _KERNEL

　　* Note: V4_PART_OF_V6 is meant to be used only for _KERNEL defined stuff

　　#define tcpb_remote V4_PART_OF_V6(tcpb_remote_v6)

　　#define tcpb_bound_source V4_PART_OF_V6(tcpb_bound_source_v6)

　　#define tcpb_ip_src V4_PART_OF_V6(tcpb_ip_src_v6)

　　#endif /* _KERNEL */

　　* These fields contain the same information as tcp_tcph->th_*port.

　　* However， the lookup functions can not use the header fields

　　* since during IP option manipulation the tcp_tcph pointer

　　* changes.

　　* offset: 0xbc，先是远端端口，后是本地端口

　　union

　　{

　　struct

　　{

　　in_port_t tcpu_fport; /* Remote port */

　　in_port_t tcpu_lport; /* Local port */

　　} tcpu_ports1;

　　uint32_t tcpu_ports2; /* Rem port， local port */

　　* Used for TCP_MATCH performance

　　} tcpb_tcpu;

　　#define tcpb_fport tcpb_tcpu.tcpu_ports1.tcpu_fport

　　#define tcpb_lport tcpb_tcpu.tcpu_ports1.tcpu_lport

　　#define tcpb_ports tcpb_tcpu.tcpu_ports2

　　* IP sends back 2 mblks with the unbind ACK for handling

　　* IPSEC policy for detached connections. Following two fields

　　* are initialized then.

　　mblk_t *tcpb_ipsec_out;

　　mblk_t *tcpb_ipsec_req_in;

　　* offset: 0xd0

　　tcp_t *tcpb_tcp;

　　* offset: 0xd8

　　* IP format that packets transmitted from this struct should use.

　　* Value can be IPV4_VERSION or IPV6_VERSION. Determines whether

　　* IP+TCP header template above stores an IPv4 or IPv6 header.

　　ushort_t tcpb_ipversion;

　　uint_t tcpb_bound_if; /* IPV6_BOUND_IF */

　　uid_t tcpb_ownerid; /* uid of process that did open */

　　#define tcp_bind_hash tcp_base->tcpb_bind_hash

　　#define tcp_ptpbhn tcp_base->tcpb_ptpbhn

　　#define tcp_conn_hash tcp_base->tcpb_conn_hash

　　#define tcp_ptpchn tcp_base->tcpb_ptpchn

　　#define tcp_time_wait_next tcp_base->tcpb_time_wait_next

　　#define tcp_time_wait_prev tcp_base->tcpb_time_wait_prev

　　#define tcp_time_wait_expire tcp_base->tcpb_time_wait_expire

　　#define tcp_last_rcv_lbolt tcp_base->tcpb_last_rcv_lbolt

　　#define tcp_state tcp_base->tcpb_state

　　#define tcp_rcv_ws tcp_base->tcpb_rcv_ws

　　#define tcp_snd_ws tcp_base->tcpb_snd_ws

　　#define tcp_ts_recent tcp_base->tcpb_ts_recent

　　#define tcp_rto tcp_base->tcpb_rto

　　#define tcp_snd_ts_ok tcp_base->tcpb_snd_ts_ok

　　#define tcp_snd_ws_ok tcp_base->tcpb_snd_ws_ok

　　#define tcp_is_secure tcp_base->tcpb_is_secure

　　#define tcp_snxt tcp_base->tcpb_snxt

　　#define tcp_swnd tcp_base->tcpb_swnd

　　#define tcp_mss tcp_base->tcpb_mss

　　#define tcp_iss tcp_base->tcpb_iss

　　#define tcp_rnxt tcp_base->tcpb_rnxt

　　#define tcp_rwnd tcp_base->tcpb_rwnd

　　#define tcp_reflock tcp_base->tcpb_reflock

　　#define tcp_refcnt tcp_base->tcpb_refcnt

　　#define tcp_remote_v6 tcp_base->tcpb_remote_v6

　　#define tcp_remote tcp_base->tcpb_remote

　　#define tcp_bound_source_v6 tcp_base->tcpb_bound_source_v6

　　#define tcp_bound_source tcp_base->tcpb_bound_source

　　#define tcp_lport tcp_base->tcpb_tcpu.tcpu_ports1.tcpu_lport

　　#define tcp_fport tcp_base->tcpb_tcpu.tcpu_ports1.tcpu_fport

　　#define tcp_ports tcp_base->tcpb_tcpu.tcpu_ports2

　　#define tcp_ipsec_out tcp_base->tcpb_ipsec_out

　　#define tcp_ipsec_req_in tcp_base->tcpb_ipsec_req_in

　　#define tcp_ipversion tcp_base->tcpb_ipversion

　　#define tcp_bound_if tcp_base->tcpb_bound_if

　　#define tcp_reuseaddr tcp_base->tcpb_reuseaddr

　　#define tcp_exclbind tcp_base->tcpb_exclbind

　　#define tcp_ownerid tcp_base->tcpb_ownerid

　　} tcpb_t;

　　#endif /* (defined(_KERNEL) || defined(_KMEMUSER)) */

　　--------------------------------------------------------------------------

　　下面这两条命令其实是用分号连在一起执行的，否则前后数据不对应，我是telnet上

　　去执行命令。

　　# ndd /dev/tcp tcp_status | grep ESTABLISHED

　　TCPB dest snxt suna swnd rnxt rack rwnd rto mss w sw rw t recent [lport，fport] state

　　30000cc21d0 ::ffff:192.168.5.8 8e0e46dc 8e0e46da 0000064010 3d49e751 3d49e751 0000024820 00583 01460 0 00 00 0 00000000 [23， 4613] TCP_ESTABLISHED

　　# skd64 0x30000cc21d0 256

　　byteArray [ 256 bytes ] ---->

　　0000000000000000 00 00 03 00 00 47 C1 80-00 00 00 00 10 48 18 88 .....G羳.....H.?

　　0000000000000010 00 00 00 00 00 00 00 00-00 00 03 00 00 3A 60 80 .............:`�

　　0000000000000020 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................

　　0000000000000030 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................

　　0000000000000040 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................

　　0000000000000050 00 00 00 00 00 00 02 47-10 00 00 00 8E 0E 46 DC .......G....?F?

　　0000000000000060 00 00 FA 0A 00 00 05 B4-8E 0B 77 07 3D 49 E7 51 ..?...磶.w.=I鏠

　　0000000000000070 00 00 60 F4 00 00 00 00-00 00 00 00 00 00 00 00 ..`?...........

　　0000000000000080 00 01 00 00 3C 00 00 00-3C 00 00 00 00 00 00 00 ....<...<.......

　　0000000000000090 00 00 00 00 00 00 FF FF-C0 A8 05 08 00 00 00 00 ......��括......

　　00000000000000A0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................

　　00000000000000B0 00 00 00 00 00 00 FF FF-C0 A8 05 82 12 05 00 17 ......��括.?...

　　00000000000000C0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................

　　00000000000000D0 00 00 03 00 00 BB 6F D0-00 04 00 00 00 00 00 00 .....籵?.......

　　00000000000000E0 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................

　　00000000000000F0 00 00 03 00 00 08 2B 68-00 00 00 00 00 00 00 00 ......+h........

　　显然0x30000cc21d0对应着一个tcpb_t结构。

　　# adb -k /dev/ksyms /dev/mem

　　physmem 3b68

　　0x30000cc21d0$

　　30000cc21d0: tcp_bind_hash tcp_ptpbhn tcp_conn_hash

　　3000047c180 10481888 0

　　30000cc21e8: tcp_ptpchn time_wait_next time_wait_prev

　　300003a6080 0 0

　　30000cc2200: time_wait_expir last_rcv_lbolt tcp_state

　　0 0 0

　　30000cc2214: tcp_rcv_ws tcp_snd_ws tcp_ts_recent

　　0 0 0

　　30000cc2220: tcp_rto

　　24c

　　snd_ts_ok 0

　　snd_ws_ok 0

　　is_secure 0

　　reuseaddr 1

　　exclbind 0

　　30000cc222c: tcp_snxt tcp_swnd tcp_mss

　　8e176ce4 f8dc 5b4

　　30000cc2238: tcp_iss tcp_rnxt tcp_rwnd

　　8e0b7707 3d49ecf0 60f4

　　30000cc2248: tcpb_reflock

　　30000cc2248: owner/waiters

　　30000cc2250: tcp_refcnt tcpb_vcf tcpb_hops

　　1 3c000000 3c

　　30000cc225c: tcpb_remote_v6

　　30000cc225c: 0 0 ffff c0a80508

　　30000cc226c: tcpb_bound_source_v6

　　30000cc226c: 0 0 0 0

　　30000cc227c: tcpb_ip_src_v6

　　30000cc227c: 0 0 ffff c0a80582

　　30000cc228c: tcpu_fport tcpu_lport ipsec_out

　　1205 17 0

　　30000cc2298: ipsec_req_in tcpb_tcp tcpb_ipversion

　　0 30000bb6fd0 4

　　30000cc22ac: bound_if ownerid

　　0 0

　　于是我们可以写这样一个脚本kill_timewait.sh

　　--------------------------------------------------------------------------

　　#! /sbin/sh

　　# @(#)kill_timewait.sh 2002-07-07 NSFocus Copyleft 2002-2012

　　# Notice here is copyleft but not copyright， enjoy it by yourself.

　　# ------------------------------------------------------------------------

　　# File : kill_timewait.sh

　　# Platform : SPARC/Solaris 8 64-bit kernel mode

　　# Author : NSFocus Security Team

　　# :

　　# Date : 2002-07-07 12:27

　　# Modify :

　　# Thanks :cdjohns@nswc-g.arpa for SunOS 4.x implementation

　　netstat -na -P tcp -f inet | grep TIME_WAIT

　　echo

　　echo 'TCPB dest [lport，fport] state'

　　echo

　　ndd /dev/tcp tcp_status | nawk '{print $1 " " $2 " " $16 $17 " " $18}' | egrep 'TIME_WAIT'

　　echo

　　/usr/bin/echo 'TCPB address to terminate: \c'

　　read tcpb_addr

　　echo

　　adb -k /dev/ksyms /dev/mem << NSFOCUS_EOF

　　$tcpb_addr$

　　NSFOCUS_EOF

　　# Check to see if this was the correct address and TCPB. state should be 6

　　echo

　　echo 'tcp_state = 6 = TCPS_TIME_WAIT'

　　/usr/bin/echo 'Is this the correct TCPB (y/n)? \c'

　　read answer

　　echo

　　case $answer in

　　[Yy]*)

　　;;

　　echo 'No Changes.'

　　exit

　　;;

　　esac

　　# Kernel Hacking， please. These value are expressed in hexadecimal.

　　TIME_WAIT_EXPIRE_OFFSET=0x30

　　STATE_OFFSET=0x40

　　# This value is expressed in decimal and must be greater than zero.

　　TIME_WAIT_EXPIRE=0t06

　　# Use adb on kernel to set the tcpb_time_wait_expire=6 and

　　# tcpb_state=TCPS_CLOSED (-6)

　　adb -kw /dev/ksyms /dev/mem << NSFOCUS_EOF

　　$tcpb_addr+$TIME_WAIT_EXPIRE_OFFSET/Z $TIME_WAIT_EXPIRE

　　$tcpb_addr+$STATE_OFFSET/W -6

　　NSFOCUS_EOF

　　echo

　　echo "TIME_WAIT state will disappear."

　　echo

　　netstat -na -P tcp -f inet | grep TIME_WAIT

　　--------------------------------------------------------------------------

　　不要设置tcpb_time_wait_expire成零，只要是一个很小的值就可以了。这里必须同

　　时设置tcpb_time_wait_expire和tcpb_state，只设置其中一个达不到效果。

　　利用adb从TCPS_ESTABLISHED变为TCPS_CLOSE_WAIT，可以使一条TCP连接不再工作，

　　但这条连接并未销毁，tcpb_t结构也未删除。

　　利用adb从TCPS_ESTABLISHED变为TCPS_CLOSED，会导致整个操作系统崩溃�？赡苁窍�

　　层tcpb_t结构被删除，而上层socket并不了解，出现非法指针。

　　简化一下kill_timewait.sh

　　--------------------------------------------------------------------------

　　#! /sbin/sh

　　ndd /dev/tcp tcp_status | nawk '{print $1 " " $2 " " $16 $17 " " $18}' | egrep 'TIME_WAIT'

　　echo

　　/usr/bin/echo 'TCPB address to terminate: \c'

　　read tcpb_addr

　　echo

　　adb -kw /dev/ksyms /dev/mem << NSFOCUS_EOF

　　$tcpb_addr+0x30/Z 0t6

　　$tcpb_addr+0x40/W -6

　　NSFOCUS_EOF

　　--------------------------------------------------------------------------

　　还可以写一个脚本自动清除所有TIME_WAIT状态TCP连接

　　--------------------------------------------------------------------------

　　#! /sbin/sh

　　ndd /dev/tcp tcp_status | nawk '{print $1 " " $2 " " $16 $17 " " $18}' | \

　　egrep 'TIME_WAIT' | cut -d' ' -f1 | while read tcpb_addr

　　adb -kw /dev/ksyms /dev/mem << NSFOCUS_EOF

　　$tcpb_addr+0x30/Z 0t6

　　$tcpb_addr+0x40/W -6

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