BeagleBone Black 之 TFTP 的搭建配置

TFTP: Trivial File Transport Protocol

TFTP 是一种简单的文件传输协议，通过UDP（User Datagram Protocol）的端口号69 来实现。TFTP 缺少很多正规的FTP的特征，主要是为小型和易于实现而设计的。TFTP仅仅读写文件到远程服务器，或从远端服务器读写文件。它无法列出目录，且不提供用户授权。因此安全性匮乏，主要用于私人本地文件传输。

xinted: eXtended InterNET Deamon

上图可以看到左图的每个服务都要自己的守护进程，来监听和处理对应端口号进来的请求；右图则有xinetd一个守护进程来监听各种端口的请求，并加载相应的服务进行处理这些请求，起到代理的作用，从而可以有效提高系统的性能；有些例外如，SMTP服务器，用于传递e-mail ，一般要求拥有自己独立的进程。

ubuntu host 端 TFTP服务器搭建：

1. 安装xinetd daemon 、tftp客户端， tftpd服务器

$ sudo apt-get install xinetd tftp tftpd

2. 配置tftp，通过xinetd daemon 来实现监听

$ cd /etc/xinetd.d  

$ sudo gedit  tftp 

   写入如下内容，并保存

service tftp {   protocol = udp   port = 69   socket_type = dgram   wait = yes   user = nobody   server = /usr/sbin/in.tftpd    server_args = "-s $tftproot"   disable = no}

3. 建立tftp的根目录

$ sudo mkdir /tftpboot

$ chmod 777 /tftpboot

4. 重载xinet.d daemon

$ sudo /etc/init.d/xinetd reload

5. 在主机上测试tftp，首先在/tftpboot目录任意建个文件

$ cd /tftpboot

$ touch test

 选择要加载目，执行相应操作命令

$ cd ~

$ tftp localhost

$ tftp > get test

 配置正确，在“～”目录下就可以找到刚建立的“test”文件了。

BBBlack 客户端操作

1. BBB的angstorm 系统已经装好 BusyBox的tftp命令，以下是命令格式

用法： tftp [OPTIONS] HOST [PORT]

传输文件来（或去）tftp 服务器

Options:

        -l FILE 本地文件        -r FILE 远端文件        -g      下载文件        -p      上传文件        

2. 在BBB terminal 上，下载文件“test”

# tftp -g -r  test 192.168.7.1

也可以这样，加上端口号

# tftp -g -r test 192.168.7.1:69

3. 修改“test”文件，上传

#tftp -p -l test 192.168.7.1

注意：上传的文件仅限制在服务器目录下，具有读写权限的同名文件，否则会如下错误提示

tftp: server error: (2) Access violation 

备注：192.168.7.1 为ubuntu host 端的ipaddress;

另附一份shell的安装命令脚本:tftp_setup.sh

#!/bin/bash# author: wiwa# date:20140613# revision:01# The document has referenced TI relative setup files.revision="revison_01"echo "The TFTP setup $revision  will be touch now...."packages2install="tftpd xinetd tftp tftpd"cmd="sudo apt-get install"check_status() {status=$?if [ "$status" != "0" ]; thenecho "Sorry Failed setup"exit 1else echo -e "Good Jobs"fi}entry_header() {cat << EOF-------------------------------------------------------------------------------Welcome TFTP server setup Interface:^_^-------------------------------------------------------------------------------EOF}stage2_install() {cat << EOF-------------------------------------------------------------------------------We now step into stage2 phase:^_^-------------------------------------------------------------------------------EOF}exit_footer() {cat << EOF-------------------------------------------------------------------------------OK OK here , see you :^_^-------------------------------------------------------------------------------EOF}# Program  startentry_header# check the missing packapgesfor i in $packages2install; dois_installed=`dpkg-query -l $i 2>/dev/null`if [ "$?" != "0" ]; thenneeds_install=`echo $needs_instal`" "$inew_cmd=`echo $cmd`" "$icmd=$new_cmdfidoneif [ "$needs_install" = "" ]; thenecho "System has all required packages"elseecho "The requires packages:$needs_install to be installed"echo "Installation requires administrator priviliges"echo "on your host. Do you wiil authorize it?"# Force the user to answer.may be you want to exitwhile true;do read -p "Type 'y' to continue or 'n' to abort:  " yn[ "$yn" == "Y" -o "$yn" == "y" -o "$yn" == "N" -o "$yn" == "n" ] && break; doneif [ "$yn" = 'n' -o "$yn" = 'N' ]; thenecho "Abort now... Thanks"exitfiecho "Performing $cmd"$cmdcheck_statusfi# enter into stage 2stage2_installtftprootdefault="/tftpboot"tftpcfg=/etc/xinetd.d/tftptftp() {    echo "service tftp{protocol = udpport = 69socket_type = dgramwait = yesuser = nobodyserver = /usr/sbin/in.tftpd server_args = "-s $tftproot"disable = no}" | sudo tee /etc/xinetd.d/tftp > /dev/null}echo "choose the directory you want to be tftp root directory"read -p "[ $tftprootdefault"] tftprootif [ "" == "$tftproot" ]; thentftproot=$tftprootdefaultfiecho "Now will set up the tftp server in the $tftproot directory."if  [ -d $tftproot ]; thenecho echo "The $tftproot exists, quit.."else sudo mkdir -p $tftprootcheck_statussudo chmod 777 $tftprootcheck_statussudo chown nobody $tftprootcheck_statusfiif [ -n "$tftpcfg" ]; then if [ -f $tftpcfg  ]; then#Use = instead of == for POSIX and dash shell complianceif [ "`cat $tftpcfg | grep args | cut -d = -f2 | sed 's/^[ ]*//'`" \      = " $tftproot" ]; then    echo "$tftproot already exported for TFTP, skipping.."else      echo "Copying old $tftpcfg to $tftpcfg.old"    sudo cp $tftpcfg $tftpcfg.old    check_status    tftpfielsetftpfielse exit 1;fiechoecho "reload the tftp server..."echo /etc/init.d/xinetd reloadcheck_statussleep 1echo "Finish the TFTP server configure."# Print the exit statement to the consoleexit_footer

参考资料列表：

wikipedia：Trivial File Transfer Protocol

配置TFTP服务器：Configuring a TFTP Server for Linux

inted 和 xinetd 介绍：http://www.ibm.com/developerworks/aix/library/au-spunix-inetd/index.html

[BusyBox] tftp usage for newbie