医院网站建设费用,无锡建设银行网站,wordpress 数据库端口,wordpress 3.8.3下载由于要使用网络通讯#xff0c;所以不可避免的要用到dhcp。理想的网络通讯方式是下面3种都要支持: 1,接入已有网络。这便要求可以作为dhcp客户端。 2,作为DHCP服务器#xff0c;动态分配IP。 3,指定固定IP 第3种情况没有什么好说的#xff0c;简单说下前2种情况。 使用步骤所以不可避免的要用到dhcp。理想的网络通讯方式是下面3种都要支持: 1,接入已有网络。这便要求可以作为dhcp客户端。 2,作为DHCP服务器动态分配IP。 3,指定固定IP 第3种情况没有什么好说的简单说下前2种情况。 使用步骤 1在内核的网络项里面把DHCP配置上 2在busybox里面把[*]udhcp server(udhcpd) [*]udhcp client(udhcpc)都选上。 udhcpd就是终端设备作为DHCP服务器 udhcpc就是终端设备作为DHCP客户端 busybox里面对dhcp都已经给出例子了 [zhhlocalhost busybox-1.14.1]$ ls ./examples/udhcp/ sample.bound sample.deconfig sample.nak sample.renew sample.script simple.script udhcpd.conf 比如使用udhcpc时 就可以直接把simple.script拿来使用改不改名字都可以busybox里面默认的目录文件是/usr/share/udhcpc/default.script 可以查看下帮助 # udhcpc --help BusyBox v1.14.1 (2010-01-22 10:35:16 CST) multi-call binary Usage: udhcpc [-Cfbnqtvo] [-c CID] [-V VCLS] [-H HOSTNAME] [-i INTERFACE] [-p pidfile] [-r IP] [-s script] [-O dhcp-option]... [-P N] -V CLASSID Vendor class identifier -i INTERFACE Interface to use (default: eth0) -H,-h HOSTNAME Client hostname -c CLIENTID Client identifier -C Suppress default client identifier -p file Create pidfile -r IP IP address to request -s file Run file at DHCP events (default /usr/share/udhcpc/default.script) -t N Send up to N request packets -T N Try to get a lease for N seconds (default 3) -A N Wait N seconds (default 20) after failure -O OPT Request DHCP option OPT (cumulative) -o Do not request any options (unless -O is also given) -f Run in foreground -b Background if lease is not immediately obtained -S Log to syslog too -n Exit with failure if lease is not immediately obtained -q Quit after obtaining lease -R Release IP on quit -P N Use port N instead of default 68 -a Use arping to validate offered address # 这样就很好理解了。 下面就说说使用udhcpd同样可以直接把busybox自带的udhcpd.conf作为参考怎么设置该文件就不详述了去参考相关文档即可。看看udhcpd怎么使用 # udhcpd --help BusyBox v1.14.1 (2010-01-22 10:35:16 CST) multi-call binary Usage: udhcpd [-fS] [-P N] [configfile] DHCP server -f Run in foreground -S Log to syslog too -P N Use port N instead of default 67 帮助一目了然。 我使用的时候直接 #udhcpd /etc/udhcpd.conf 即可。 还有一个租约文件要简要说说使用udhcpd时会要求建立一个租约文件按照提示创建一个就行了它起什么作用呢就是为了记录客户端所获得的IP如果没有租约文件则会重新给客户端分配一个新IP如果有则使用原先分配的IP。 例如udhcpc -i wlan0是获取wlan0的ip地址如果想获取之后直接退出添加 -q参数即udhcpc -q -i wlan0 udhcpc切换到后台 它自带参数可以实现该功能。如下 udhcpc -b -i eth0 -p /var/run/udhcpc.pid -R 解释一下-b就是切换到后台指令-i是指定使用哪个网络接口双网卡的时候一定要使用它来指定eth0 or eth1。 对于 -R参数其实也很重要在关闭udhcpc时可以向dhcpserver发送release取消租约。 udhcpc scripts Heres some debian scripts I wrote for udhcpc 0.9.6. I wanted to make it easy to run local scripts for DHCP changes so I created /etc/udhcpc.d. All the /usr/share/udhcpc/default.* scripts have been merged into /etc/udhcpc.d/S50default. S99local is an example script that patches resolv.conf and calls a DNS update script. /etc/init.d/udhcpc /etc/udhcpc.script /etc/udhcpc.d/S50default /etc/udhcpc.d/S99local http://udhcp.busybox.net/README.udhcpc udhcp client (udhcpc) -------------------- The udhcp client negotiates a lease with the DHCP server and notifies a set of scripts when a leases is obtained or lost. command line options ------------------- The command line options for the udhcp client are: -c, --clientidCLIENTID Client identifier -H, --hostnameHOSTNAME Client hostname -h, Alias for -H -f, --foreground Do not fork after getting lease -b, --background Fork to background if lease cannot be immediately negotiated. -i, --interfaceINTERFACE Interface to use (default: eth0) -n, --now Exit with failure if lease cannot be immediately negotiated. -p, --pidfilefile Store process ID of daemon in file -q, --quit Quit after obtaining lease -r, --requestIP IP address to request (default: none) -s, --scriptfile Run file at dhcp events (default: /usr/share/udhcpc/default.script) -v, --version Display version If the requested IP address cannot be obtained, the client accepts the address that the server offers. udhcp client scripts ------------------- When an event occurs, udhcpc calls the action script. The script by default is /usr/share/udhcpc/default.script but this can be changed via the command line arguments. The three possible arguments to the script are: deconfig: This argument is used when udhcpc starts, and when a leases is lost. The script should put the interface in an up, but deconfigured state, ie: ifconfig $interface 0.0.0.0. bound: This argument is used when udhcpc moves from an unbound, to a bound state. All of the paramaters are set in enviromental variables, The script should configure the interface, and set any other relavent parameters (default gateway, dns server, etc). renew: This argument is used when a DHCP lease is renewed. All of the paramaters are set in enviromental variables. This argument is used when the interface is already configured, so the IP address, will not change, however, the other DHCP paramaters, such as the default gateway, subnet mask, and dns server may change. nak: This argument is used with udhcpc receives a NAK message. The script with the deconfig argument will be called directly afterwards, so no changes to the network interface are neccessary. This hook is provided for purely informational purposes (the message option may contain a reason for the NAK). The paramaters for enviromental variables are as follows: $HOME - The set $HOME env or / $PATH - the set $PATH env or /bin:/usr/bin:/sbin:/usr/sbin $1 - What action the script should perform interface - The interface this was obtained on ip - The obtained IP siaddr - The bootp next server option sname - The bootp server name option boot_file - The bootp boot file option subnet - The assigend subnet mask timezone - Offset in seconds from UTC router - A list of routers timesvr - A list of time servers namesvr - A list of IEN 116 name servers dns - A list of DNS server logsvr - A list of MIT-LCS UDP log servers cookiesvr - A list of RFC 865 cookie servers lprsvr - A list of LPR servers hostname - The assigned hostname bootsize - The length in 512 octect blocks of the bootfile domain - The domain name of the network swapsvr - The IP address of the clients swap server rootpath - The path name of the clients root disk ipttl - The TTL to use for this network mtu - The MTU to use for this network broadcast - The broadcast address for this network ntpsrv - A list of NTP servers wins - A list of WINS servers lease - The lease time, in seconds dhcptype - DHCP message type (safely ignored) serverid - The IP of the server message - Reason for a DHCPNAK tftp - The TFTP server name bootfile - The bootfile name additional options are easily added in options.c. note on udhcpcs random seed --------------------------- udhcpc will seed its random number generator (used for generating xids) by reading /dev/urandom. If you have a lot of embedded systems on the same network, with no entropy, you can either seed /dev/urandom by a method of your own, or doing the following on startup: ifconfig eth0 /dev/urandom in order to seed /dev/urandom with some data (mac address) unique to your system. If reading /dev/urandom fails, udhcpc will fall back to its old behavior of seeding with time(0). signals accepted by udhcpc ------------------------- udhcpc also responds to SIGUSR1 and SIGUSR2. SIGUSR1 will force a renew state, and SIGUSR2 will force a release of the current lease, and cause udhcpc to go into an inactive state (until it is killed, or receives a SIGUSR1). You do not need to sleep between sending signals, as signals received are processed sequencially in the order they are received. compile time options ------------------- options.c contains a set of dhcp options for the client: name[10]: The name of the option as it will appear in scripts flags: The type of option, as well as if it will be requested by the client (OPTION_REQ) code: The DHCP code for this option 实现DHCP自动获取IP地址 分类 LINUX 前提系统已经实现DNS即使用pingwww.baidu.com测试时能ping通。 1 在内核中添加以下选项 Networking --- [*] Networking support Networking options --- * Packet socket //添加.配置CONFIG_PACKET [ * ] IP: DHCP support //添加 [ * ] Network packet filtering (replaces ipchains) --- //添加后面子选项可不选配置CONFIG_NETFILTER 说明若没选* Packet socket, [ * ] Network packet filtering (replaces ipchains) ---选项在执行udhcpc命令时出现如下错误 ~ # udhcpc udhcpc (v0.9.9-pre) started udhcpc[208]: udhcpc (v0.9.9-pre) started FATAL: couldnt listen on socket, Address family not supported by protocol udhcpc[208]: FATAL: couldnt listen on socket, Address family not supported by protocol 2 Busybox中添加以下选项 Networking Utilities --- udhcp Server/Client --- [] udhcp Server (udhcpd) //在此不作服务端故不选。生成udhcpd命令 [*] udhcp Client (udhcpc) //生成udhcpc命令 [ ] Lease display utility (dumpleases) [ ] Log udhcp messages to syslog (instead of stdout) [ ] Compile udhcp with noisy debugging messages 若busybox没编译相应选项也可从网上下载相应文件用arm-linux交叉编译得到udhcpd,udhcpc命令copy到usr/sbin下就可以了。 我从 网上 下的udhcp_0.9.8cvs20050303.orig.tar.gz文件 解压后修改Makefile文件 在19行添加CROSS_COMPILEarm-linux- 注释12行的COMBINED_BINARY1否则不生成udhcpc命令。 3 建相关配置文件 从busybox的examples/udhcp/下copy simple.script文件到开发板/usr/share/udhcpc/下并重命名为default.scriptudhcp_0.9.8cvs20050303.orig.tar.gz中也有这样的文件。 [rootlocalhost root]# vi usr/share/udhcpc/default.script #!/bin/sh # udhcpc script edited by Tim Riker TimRikers.org [ -z $1 ] echo Error: should be called from udhcpc exit 1 RESOLV_CONF/etc/resolv.conf [ -n $broadcast ] BROADCASTbroadcast $broadcast [ -n $subnet ] NETMASKnetmask $subnet case $1 in deconfig) /sbin/ifconfig $interface 0.0.0.0 ;; renew|bound) /sbin/ifconfig $interface $ip $BROADCAST $NETMASK if [ -n $router ] ; then echo deleting routers while route del default gw 0.0.0.0 dev $interface ; do : done for i in $router ; do route add default gw $i dev $interface done fi echo -n $RESOLV_CONF [ -n $domain ] echo search $domain $RESOLV_CONF for i in $dns ; do echo adding dns $i echo nameserver $i $RESOLV_CONF done ;; esac exit 0 4 重启开发板执行udhcpc就可自动获取IP地址了以下是执行udhcpc的输出信息 ~ # udhcpc udhcpc (v0.9.9-pre) started udhcpc[228]: udhcpc (v0.9.9-pre) started Sending discover... udhcpc[228]: Sending discover... Sending select for 192.168.1.109... udhcpc[228]: Sending select for 192.168.1.109... Lease of 192.168.1.109 obtained, lease time 86400 udhcpc[228]: Lease of 192.168.1.109 obtained, lease time 86400 deleting routers route: SIOC[ADD|DEL]RT: No such process adding dns 192.168.0.1 ~ # ping www.baidu.com PING www.a.shifen.com (220.181.38.4): 56 data bytes 64 bytes from 220.181.38.4: icmp_seq0 ttl52 time1219.0 ms [1] Stopped ping www.baidu.com 5 如果是双网卡必须用参数指明 例udhcpc -i eth1 Linux下hosts、host.conf、resolv.conf的区别 分类 LINUX 这三个文件都位于 /etc/目录下在这里区分一下 1.hosts文件. 和Windows系统下的host的文件相类似就是一个文本文件里面存放一些IP和域名的对应关系。 2.host.conf. #解析器查询顺序配置文件 例vi /etc/host.conf order hosts bind 表示先查询本地hosts文件如果没有结果再尝试查找BIND dns服务器。 3. resolv.conf 配置Linux系统DNS服务器的配置文件 vi /etc/resolv.conf nameserver 192.168.0.1 nameserver 202.99.96.68
