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    主页 > 养生保健 > SPARC/Solaris 8下快速终结TCP有限状态机的TIME_WAIT状态

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

    发表日期:2020-10-15 | 来源 :澳洲幸运5群 | 点击数: 次 收听:
     

      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

      0

      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

      $q

      #

      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

      $tcpb_addr$

      $q

      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

      $q

      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

      $q

      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

      do

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

      $tcpb_addr+0x30/Z 0t6

      $tcpb_addr+0x40/W -6

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