configuration training ~ lua script ~

Yamaha Router Configuration Training

~ Lua script ~

© Yamaha Corporation

Lua script

Simple and powerful scripting language. - http://www.lua.org Lua script interpreter is embedded in Yamaha router. With Yamaha router … - Monitor the system log and change the configuration. - Send e-mail to report the network status . - Change the routing policy dynamically. - Shutdown the switch’s port that connect to malicious computer. - Write a simple network server/client with LuaSocket library.

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http://www.lua.org/


Topology

RTX810

Console cable (Tera Term)

LAN cable

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© Yamaha Corporation 4

Hello, world!

Make a script that print out the string “Hello, world!”.

1. Start the memo. 2. Write “ print (“Hello, world!”) “. 3. Create a new line at the bottom of file. 4. Save the memo as “helloworld.lua” with ascii code.

Challenge

© Yamaha Corporation 5 5

USB Memory settings

1. Save helloworld.lua to USB memory. In this case, save to root directory.

2. Connect the USB Memory to RTX810’s USB port.


Execute Lua script

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Sample:

・helloworld.lua is automatically compiled and execute. ・script output is displayed on console.

Lua <LUA_SCRIPT>

Command


Other method of executing Lua 1. Transfer the Lua script file to router by using TFTP.

1-1. Set “tftp host any” on router console. 1-2. Transfer the Lua script to router.

2. Execute “ Lua <LUA_SCRIPT>” on router console.

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Other method of executing Lua

・calculate the number. ・calculate negative number. ・decimal number can not be calculate.

Lua –e ‘<LUA_SCRIPT>’

Command

Sample:

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Test case (variable)

Number

a = 12 b = 2 a = a * b print(a)

String

str1 = “I like “ str2 = “music.” str1 = str1 .. str2 print(str1) Addition of strings

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Test case (for loop)

for i=1, 10 do print (i, “Hello, world!”) end

Check the result of following script.

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Lua status check

・Use “show status lua”. ・Check Compile error.

In case of Lua script was not executed correctly …

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Training1

# lua /double.lua 1 1 2 4 3 9 4 16 ･･･ 10 100

Result for i = 0, 10 do print (i, i * i) end

Example i = 0 while i < 10 do print (i, i * i) i = i + 1 end

Example

Make a Lua script that calculate n2 (n = 1～10) Challenge

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Training2

# lua /factorial.lua 1! = 1 2! = 2 3! = 6 4! = 24 ･･･ 10! = 3628800

Result tostring () … connect the string and number. Example (I am 30 years old.) ------------------------------------------------------------ age = 30 print (“I am ” .. tostring (age) .. “ years old”) ------------------------------------------------------------

Hint

factorial = 1 for i = 1, 10 do factorial = factorial * i print (tostring(i) .. “! = “ .. tostring(factorial)) end

Example

Make a Lua script that calculate n! (n = 1～10) Challenge

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Execute router command

ARG1 … true or false ARG2 … output of COMMAND ARG1, ARG2 = rt.command (<COMMAND>)

Lua script library

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Execute router command Example

In case of ping is available, rtn is true.

In case of ping is not available, rtn is false.

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Training 3

Make a Lua script that display the status of all lan interface. Hint: use for loop and “show status lanN” command.

Challenge

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Training 3

cmd = “show status lan” for i = 1, 2 do cmd_n = cmd .. tostring (i) rtn, str = rt.command(cmd_n) if rtn then print (cmd_n .. “ output:¥r¥n” .. str) else print (“Command error:” .. cmd_n) end end

Example code

・ ¥r¥n means line feed.

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Terminate Lua In case of Lua script become an infinite loop process …

while true do i = 1 end

Example Infinite loop

terminate lua <LUA_TASK_ID> terminate lua file ‘<LUA_SCRIPT>’

Command

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Send E-mail

・Make table for mail. ※ If necessary, set ID & password. smtp_auth_name = ID smtp_auth_password = password ・Check the result.

rt.mail (<TABLE>)

Lua script library

Sample:

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Training 4

Make a Lua script that send e-mail to you. E-mail title is command. E-mail contents is the output of “show environment”. Hint: Set the string to table factor. mail_tbl.subject = NAME mail_tbl.text = STRING

Challenge

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Training 4

・Set the output of command. ・Set the command to subject. ・In case of fail to send email, error output print to console.

cmd = “show environment” mail_tbl = { smtp_address = “mail.test.test”, from = [email protected], to = [email protected] } rtn, str = rt.command(cmd) if rtn then mail_tbl.text = str mail_tbl.subject = cmd if not rt.mail(mail_tbl) then print(“Send mail failure”) end end

Example

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Execute command regularly

・Make a Lua script that show the configuration at 30 second intervals. ・Delay the process of Lua script until after the specified time.

rt.sleep (<SLEEP_TIME>)

Lua script library

Sample:

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Function definition

・Make a function that execute ping. ・Delay the process of Lua script until after the specified time.

Sample:

Make a Lua script that execute ping to www.example.com at 30 second intervals.

Challenge

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Take out the string

string.match(<STRING>, <PATTERN>) Search the <PATTERN> from <STRING>

Lua script library

Sample:

Make a Lua script that print the number of dhcp leased addresses. Challenge

・Search “Leased: “ and print the number that following the string “Leased: “.

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Training 5

Make a Lua script that send e-mail to you at 30 second intervals. E-mail title is “CPU utilization”. E-mail contents is “Current CPU utilization is ○○%.” Hint: For Getting the number of CPU utilization, string.match (str, “CPU:%s+(%d+)%%”)

Challenge

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Training 5

-- execute command and return result function exec_cmd(cmd) rtn, str = rt.command (cmd) if rtn and str then return true, str else return false end end mail_tbl = { subject = "CPU utilization" ･･･ (omission) } cmd = "show environment"

Example interval = 30 output = "Current CPU utilization is " while true do rtn, str = exec_cmd (cmd) if rtn then mail_tbl.text = output .. string.match(str, "CPU:%s+(%d+)%%") .. "%" if not rt.mail(mail_tbl) then print ("Fail") end end rt.sleep (interval) end

Continuation of Example

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Get number from system log

rt.syslogwatch (<PATTERN>) Search the <PATTERN> from router’s system log.

Lua script library

Sample:

Make a Lua script that print the information of LAN linkup. Challenge

・Monitor the system log and detect the specified log, move to next process. ・Get the port number from detected system log.

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Training 6

Make a Lua script that output the information of LAN2 linkup and linkdown to system log. format : “LAN2 interface linked up/down” In default, LAN2 linked up. Hint: The system log that you should detect. - linkup … LAN2: link up - linkdown … LAN2: link down Use rt.syslog(<TYPE>, <TEXT>) to output the string to system log.

Challenge

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Training 6 Example

Pattern = “LAN2: link” While true do rtn = rt.syslogwatch (pattern .. “down”) if rtn then rt.syslog (“info”, “LAN2 interface linked down”) end rtn = rt.syslogwatch (pattern .. “up”) if rtn then rt.syslog (“info”, “LAN2 interface linked up”) end end

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Training 7

・Send E-mail to you at 60 second intervals. ・E-mail title is router’s current time, format is YEAR/MONTH/DATE XX:XX:XX. ・E-mail contents are following ----------------------------- CPU: XX% (5sec) CPU: XX% (1min) CPU: XX% (5min) Memory: XX% used -----------------------------

Make a Lua script that …

Procedure

1. Get the information about current time and CPU from “show environment”. 2. Make a content from the information.

Hint : Use string.find() and string.sub. ※ But you may use other functions. 3. Send E-mail to yourself.

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Training 8

Internet

・If the PPPoE is disconnected, use the route through USB 3G to access internet and output the log “Change the route to mobile”. ・If the PPPoE is connected, use the route through PPPoE to access internet and output the log “Change the route to PPPoE”.

Make a Lua script that …

PPPoE (LAN2)

USB

3G

LAN1

192.168.100.0/24

Procedure

1. Make a environment to access internet with PPPoE and USB 3G.

2. Monitor the following log - “PPPOE[01] PPPoE Connect” - “PPPOE[01] Disconnected”

3. Change the route “ip route default gateway **”.

4. Check the connectivity by using ping from PC.

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configuration training ~ lua script ~

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