Howto: Getting CUPs working on OpenWRT guide

TP-LINK WR1043ND

This has been so painful.

I’ve spent hours trying to get this working with little info on google searches for when things have gone wrong.

Fortunately, I have got it working! Hopefully this guide will be of some help if you’re trying to get CUPs working on your wireless router.

What is CUPs? printing….from your wireless router???
CUPs is a linux print server. Using a wireless router, such as the TP-LINK WR1043ND, we’re able to install a new open source firmware such as OpenWrt, and further install different packages, such as CUPs, allowing us to do a lot more with our devices than the manufacturer originally intended.

Issues upon issues…

My first attempt at this saw many different issues.  If you really want to see what I was struggling with, I have a forum post about them here: https://forum.openwrt.org/viewtopic.php?id=39990

A fresh start

It was time I started again from scratch. I decided I would try out a bleeding edge build and I am now running OpenWrt Attitude Adjustment 12.09-beta, LuCI Trunk (trunk+svn9220). My reason for this is the off chance a package I had installed may have been having issues with “stable” which hasn’t been updated in almost a year (http://downloads.openwrt.org/backfire/10.03.1/ar71xx/ shows Dec 2011).

Equipment:
- TP-Link WR1043ND Wireless router
- 10 port powered USB hub (overkill but I got it cheap. The WR1043ND doesn’t do a good job providing power to USB devices, so without a powered hub, you may see strange issues, especially with USB 3G modems.)
- 2GB USB stick (This will be used for spooling for CUPs)
- Brother HL5240 Laser Printer
- Canon MX310 Multifunction Printer

Step 1: Install OpenWRT on your wireless router.

There are enough guides online on this, and I won’t cover it here. All I’m going to say is if you’re currently running OpenWRT and you want to try another version of it, login to your router via the web, then System > Backup / Flash Firmware > Flash new firmware image.

Normally you would download a sysupgrade .bin but I used a factory.bin. This is because I was going between different versions of OpenWRT and I’m not sure if a sysupgrade version may have caused issues. I also unticked “keep settings” since I wanted it back to default config.

Flash the firmware then re-setup any of your basic config (passwords, ip address, wireless SSID etc).

Step 2: Prepare your router for CUPs

At this point, you’ve probably already seen the CUPs guide on the OpenWRT site and are probably stuck on it. Hopefully the below steps will be of some help.

For me running ATTITUDE ADJUSTMENT (12.09-beta, r33312), all the required usb packages were already installed. You can check what packages are installed by entering opkg list-installed, or via web by going System > Software.

Basically before you install CUPs you need:
kmod-usb-core
kmod-usb-ohci
libusb

I think you may also need kmod-usb2, and hotplug2.  I have them installed anyway.

CUPs also needs:
zlib, libpthread,  libpng, libjpeg, libstdcpp, and if you’re using a canon printer, you may need cups-bjnp. Note, for all of the above, except cups-bjnp, they may be dependencies for CUPs and I didn’t have to manually install any of them. I have a feeling they all just installed when I installed CUPs.

To install:

opkg update
opkg install kmod-usb-core kmod-usb-ohci libusb kmod-usb2 hotplug2

Make sure you don’t have kmod-usb-printer installed or running.
Why? because CUPs talks directly to the printers and kmod-use-printer is another layer which is used by other apps such as p910nd to communicate with the printer. This is also the reason why you won’t see lp0 under /dev.

Right! Prerequisites are out of the way, lets actually install CUPs!

Step 3: Installing CUPs

From the command line: opkg install cups

That was probably the easiest step of the lot.

Now that CUPs is installed, there’s a bit of config you need to do before it will probably work. As detailed on a forum post on www.newren.com.au, you need to do the following:

Use a text editor (e.g. vi) to open  /etc/cups/cupsd.conf, so:

root@OpenWrt:/# vi /etc/cups/cupsd.conf

change
User Nobody
Group Nobody

to:
User root
Group root

And change AuthClass to AuthClass Anonymous.

Remember to change allowed network to your network,  otherwise you won’t be able to find the printer. E.G:

<Location />
Order Deny,Allow
Allow From 127.0.0.1
Allow From 192.168.0.0/24
</Location>

Change “Allow From 192.168.0.0/24″ to the IP subnet you’re using.

Use “:wq” to save the file and quit. Personally I prefer using the text editor nano, so I did opkg install nano, and then nano /etc/cups/cupsd.conf, edited the file, then ctrl + x, Y, enter.

Then, you need to change the permissions on /usr/lib/cups/backend/usb to 700.

To do this, enter: chmod 700 /usr/lib/cups/backend/usb.

This changes the behavior of cups, which normally tries to execute the backend through a user account other than root. This forces the backend to run as root from cups.

Okay! Got this far? Try entering the following command:

root@OpenWrt:/# /usr/lib/cups/backend/usb

You should hopefully see something like:

DEBUG: list_devices
DEBUG: usb_find_busses=1
DEBUG: usb_find_devices=7
direct usb://Canon/MX310%20series?serial=406F4E&interface=1 “Canon MX310 series” “Canon MX310 series” “MFG:Canon;CMD:BJL,BJRaster3,BSCCe,PLI;SOJ:TXT01;MDL:MX310 series;CLS:PRINTER;DES:Canon MX310 series;VER:1.030;STA:10;HRI:EU;MSI:E3;” “”

Yus! This is a good sign! This means that CUPs is talking correctly with your printers. Get an error? I originally had:

root@OpenWrt:/usr/lib/cups/backend# /usr/lib/cups/backend/usb
/usr/lib/cups/backend/usb: can’t load library ‘libusb-0.1.so.4′

 

Fix:
root@OpenWrt:/usr/lib# opkg update
Downloading http://downloads.openwrt.org/backfire/10.03.1/ar71xx/packages/Packages.gz.
root@OpenWrt:/usr/lib# opkg install libusb

Step 4: Accessing CUPs

To access cups, enter http://ip-address-of-your-router:631/admin, so for me it’s http://192.168.0.1:631/admin

You may be requested to login, just use your root account, unless you’ve created another account.

Next go Admin > Add Printer, and you should be presented with the following screen:

CUPs add printerAs you can see, CUPs HAS picked up both my printers correctly, and I’m able to go through each following step in setting them up. What if CUPs doesn’t show anything there for you?

Try the following, which was posted on http://9m2tpt.blogspot.co.nz/2012/01/cups-hl-2140-usb-printer-wzr-hp-g300nh.html:

To add the printer, just go to http://your-router-ip-address:631 Go to administration, add printer, select the AppSocket/HP JetDirect option. Remember the output from /usr/lib/cups/backend/usb? Use the URI there and paste it into the “Connection” field. Example, for my printer, the URI returned by the backend command is: usb://Brother/HL-2140%20series?serial=F9J555425

Okay! So if your printers DID show up and you didn’t have to do the paragraph above, select your printer and click next. There’s two ways you can install your printer. You can either install it as RAW, or you can install a PPD file for your printer. Without going into detail, I believe you’re better off installing using a ppd file. If my case with the Brother HL5240, I was able to get the ppd file from: http://www.openprinting.org/printer/Brother/Brother-HL-5240

Go through all the steps and you should have your printer sitting as idle under printers. At this point, you should be able to add your printer on a client and try printing a test page.

Note: Due to limited functionality of CUPs on the router, you can’t print a test page from within CUPs on the device.

Step 5: Configuring a Windows 7 Client for the CUPs Printer

1. Click Start, and type add a printer.
2. Click add a network, wireless, or Bluetooth printer.
3. Click “The printer  that I want isn’t listed.”

4. Select the second option, and paste the full URL to the printer. In CUPs, select Printers > followed by the printer itself. The url in your address bar is what you should paste below. Then install the correct drivers for your device. On the last screen you could click “print a test page” followed by finish.

At this point, hopefully a test page has printed. Wohoo!!

I spent hours getting to this point. And it’s a fantastic feeling having your wireless router act as a print server. The thing to remember is, it’s not over yet….

Configure a USB drive for spooling storage

One issue that we face having a wireless router act as a print server, is that this wasn’t its original function, and therefore there are certain constraints that we must get around. 1 is that the router has an extremely small and limited internal memory. With CUPs, when a user sends a job to the printer, the whole file gets transferred across, and needs to be stored, or cached somewhere while the printer gets ready to start printing. Therefore, we need to set up a usb drive for spooling. You may get away with not having to do this step, but you also may have print job issues down the track if you’re printing a big file. Chances are you have a spare usb flash drive lying around not being used, so why not just do the extra step.

For this step, there are other guides online for configuring a flash drive for OpenWrt, not to mention the OpenWrt usb storage page. There’s quite a good guide on it here. For me though, I have a linux Mint laptop, so I just plugged in my spare usb drive, apt-get installed gparted, and then configured 90% of the flash drive with ext4, and the last 10% as SWAP. I also changed the permissions on the flash drive and used permissions you probably shouldn’t use by doing “sudo chmod 777 /mnt/flash drive” which basically gives all users read write and execute permissions. For me I don’t think there will be any issues with this.

Following the guides above, I did:
opkg update
opkg install kmod-usb-storage kmod-fs-ext4 block-mount

At this point there is two ways you could mount your storage, either using the CLI/SSH or via the gui web page. Personally doing it with the web page, as I find it easier.

If you don’t have the tab “Mount Points” it’s probably because you don’t have all the right packages installed. It didn’t appear for me till I added “block-mount”.

openwrt add usbNext reboot your router and make sure the usb device comes up mounted correctly on the above page. At this point it may be a good idea just to do a blank page print to your printer to ensure everything is still working fine. Okay next step!

Configure CUPs to use your USB device for print jobs

Time to re-edit your CUPs config. Either use VI or your text editor of choice and edit your cupsd.conf file:

nano /etc/cups/cupsd.conf

Change:
RequestRoot /var/cups
TempDir /var/cups

I changed both to /usb/cups/ since as you can see in the above screen cap I mounted my usb drive as /usb

You probably should restart CUPs now.Do this by:
root@OpenWrt:~# /etc/init.d/cupsd restart

Also if at some point you’ve restarted your device and CUPs hasn’t started, do either of the following:

enter “/etc/init.d/cupsd enable” or alternatively in the gui go to System > Started, and make sure cupsd has enabled beside it.

Speaking of cleaning up
Could be a good point to get rid of those default printers you’re not using.

Firstly stop the cups service: /etc/init.d/cupsd stop

I just commented out the printers doing nano /etc/cups/printers.conf and putting a # beside them eg #<Printer LP> and #<DefaultPrinter USB> syslog will throw up a couple of errors on start up but that shouldn’t matter. Alternatively just delete everything for the two defaults.
Then do:
/etc/init.d/cupsd start

Adding the printers on a Mac Client.
I had issues adding the printers through the default mac config, but then suddenly remembered that Macs actually run a local version of CUPs so I just added them by going into the web browser http://127.0.0.1:631 and adding the printers in there! Works great!

 

Hopefully you made it this far, and have a working version of CUPs on your wireless router! Congrats!

Got an issue that you’ve been stuck in for hours?  Always try doing some debug, E.g. via the web interface, go Status > System Log, or Kernel Log. Both of which can be pretty helpful.

As a last resort, if you’ve really stuffed things up, a fresh install might be the way to go. Fixed things for me!

Got any questions? feel free to write below.

 

—————————————————————————————————————————
Other Resources:

Quite a good guide if you’re wanting to use p910nd as your print server:
– http://chee-yang.blogspot.co.nz/2011/11/make-host-based-usb-printer-work-with.html

USB flash drive on OpenWRT 10.03 Backfire HOWTO:
http://asomewhatintegratedlife.blogspot.co.nz/2010/09/usb-flash-drive-on-openwrt-1003.html

Other CUPs on OpenWrt install guides around the web:
- www.newren.com.au/ibbs/forum.php?mod=viewthread&tid=392
- http://9m2tpt.blogspot.co.nz/2012/01/cups-hl-2140-usb-printer-wzr-hp-g300nh.html

Another all in one guide which covers pretty much everything except a print server:
– http://knowhow.bart.prokop.name/install/openwrt/wr1043nd

24 thoughts on “Howto: Getting CUPs working on OpenWRT guide

  1. Thanks very much. I’ve tried that on Backfire box and it works. Especially that chmod part was what I missed. I have HP printer so I installed also hplip, so I chmoded backend/hp instead of usb. Since then Find new printer worked but only raw queue seems to work but haven’t tried a lot.

    • Glad to hear that was of help! Yeah I possibly could have mentioned something about HP printers, but not having one I didn’t have to do any config regarding it. In terms of only raw queue working, have you tried installing PPD files for your printers? To be honest, I’m not sure if that was needed, but I did it anyway for both my printers. The other thing to mention, have you got the windows/mac drivers (depending on your OS)? On each machine, I installed the network printers with the actual drivers, rather than RAW. Works for me on all the devices I’ve tried. I guess it’s a matter of potentially finding the drivers though.

      Next step for me is to try get scanning working (using SANE).

      Thanks,

      Matt

      • There is no problem to have the printer as RAW queue (precisely “Driver: Local Raw Printer (grayscale)”). We have also Windows PC. So the printer is added to Linux/Win systems by URL with appropriate drivers from system. It seems to me as best possible option. I’d like to have SANE working too, but there is even less resources of information then these about CUPS. You will hear from me as soon as I discover something.

      • Hi again, yesterday I have made SANE working. I think main problem is to have propper backend such as hp.conf or any else in /etc/sane.d/. I wrote down what I did, maybe something help you, but I did everything what I have found and I don’t know whether everything written is required or something still missing.

  2. To enable a CUPS printer on MAC, just install the PPD and use URL lpd://router.name/printername

    That’s all.

  3. Hi Matt,
    thanks for the howto. It worked for me but my TP-link needed some tweaking because it needs to upload fimrware to my HP laserjet P1005. Maybe you can add the following to your HowTo?

    The above installation worked well but when I wanted to print something, nothing happens. There is a job in the job que and it also calls it finished. This is because the printer needs firmware uploaded via USB to function properly.

    Download the appropriate firmware for your HP laserjet from: http://oleg.wl500g.info/hplj/ and put it in /usr/lib.

    Then use the following command to upload the firmware to the printer:

    DEVICE_URI=”usb://HP/HP%20LaserJet%20P1005?serial=BB0417Y” /usr/lib/cups/backend/usb 1 1 1 1 ” /usr/lib/sihpP1005.dl

    Where “usb://HP/HP%20LaserJet%20P1005?serial=BB0417Y” needs to be replaced with yours. You can find it by using the /usr/lib/cups/backend/usb command.

    The next thing to do is to create some hotplug script to upload the firmware each time the printer turns on. I will put it here when I have a working hotplug script.

    • As promised:

      #!/bin/sh
      #Hotplug script to auto upload firmware on connect or power on with CUPS USB backend
      #
      #Path to your firmware (for HP FW see http://oleg.wl500g.info/hplj/):
      FIRMWARE=”/usr/lib/sihpP1005.dl”
      #$Product = IDvendor/IDproduct/bcdDevice (get it with lsusb -v)
      if [ "$PRODUCT" = "3f0/3d17/100" -a "$ACTION" = "add" ]
      then
      logger -t HotplugScript Activating HP LaserJet FW upload script…..
      sleep 10
      logger -t HotplugScript Sending firmware to printer……
      DEVICE_URI=”usb://HP/HP%20LaserJet%20P1005?serial=BB0417Y” /usr/lib/cups/backend/usb 1 1 1 1 ” $FIRMWARE
      logger -t HotplugScript done!
      fi
      sleep 1

      Save it in /etc/hotplug.d/usb

      • Cheers. I’m sure this will help someone. Just added a link to the comment on the OpenWrt CUPs wiki page.

  4. I’ve followed your steps for adding a printer under Win7. When I try to add my printer in the Windows configuration dialog (“http://192.168.0.3:631/printers/HP_LaserJet_1200″), I always get the message “cannot connect to printer”. Any ideas for help? :-)

  5. Hi,

    Having issues getting my printer listed when running this command. Any advice?

    root@OpenWrt:~# /usr/lib/cups/backend/usb
    DEBUG: list_devices
    DEBUG: usb_find_busses=1
    DEBUG: usb_find_devices=3

    • Hi there,

      I’m currently overseas and not really able to offer that much advice.

      Not knowing anything about your setup my suggestions can only be:

      – Reread the stuff above that point in the guide.
      – Are you able to try another printer and see if it detects it?
      – could also be your version of openwrt. As above I had issues with certain versions.
      – if you are using a USB hub make sure it’s a powered one.
      – you haven’t tried installing p910nd or something else that attempts to take control of printers or USB devices? If so, personally a re install of openwrt might be the best option.

      If nothing above is helpful, more info about your set up would be e.g. devices you’re using and connecting, version of openwrt etc.

      Thanks,

      Matt

  6. Pingback: OpenWRT a CUPS | Honzův blog

  7. Hi,
    I followed your great guide. I’m stuck however with one problem.
    Printing txt files, printer self-test pages or webpages from chrome is no problem. When I try to print a docx or pdf file, I does not work. I already increased CUPS cache but that didn’t help.

    • Hmmm. I wonder if its worth trying to find some different drivers for your printer? My understanding of printers is you have two types of drivers, postscript and PCL. I forget which does what, but from memory one simply sends the file straight to the printer and the printer does the processing, and the other processes the file on the computer first before sending to the printer. I could be talking rubbish here but it could be worth looking into.

    • Hi Rini,

      I presume 192.168.1.1 is in fact the IP address of your OpenWRT device?

      Are you sure you followed Step 3 onwards correctly? you need to make sure your wireless routers IP subnet is permitted.

      Also worth confirming cups is actually running:

      root@OpenWrt:~# ps | grep cups
      1596 root 4192 S /usr/sbin/cupsd -C /etc/cups/cupsd.conf

      If it’s not, enter:
      /etc/init.d/cupsd start

      Thanks,

      Matt :)

      • Hi,

        I have the same problem but in my case cupsd will not even start.

        When I run:

        /etc/init.d/cupsd restart

        I get

        cupsd: Child exited with status 1!

        cupsd is enabled in System > Startup and I cannot find the CUPS log in /var/log/cups/error_log (I tried setting the LogLevel to debug just to try and catch any startup errors but nothing.)

        Do you have any idea where to look into why cups is not starting? Since there is no cupsd process, the admin panel is unavailable.

        Also, thank you for the blog post, it really simplified the CUPS installation process! :)

        • Hi Slaven,

          I’m really not too sure sorry.

          I wonder if cups initially installed properly. I also wonder if the current cups version in the repo is compatible with all versions of OpenWRT.

          I don’t actually use Cups anymore, as I now just have 2 network printers, so my knowledge of cups and openwrt isn’t as good as it was 2 years ago when I did this.

          If you do manage to figure it out, I’d suggest following up to your comment, in case someone does a google with the same problem.

          Thanks,

          Matt

  8. Hi Mattie,
    Sorry for late respon your advice. my network printer done after I enter /etc/init.d/cupsd start

    but I still confuse,
    i runs 3 printers on my router, and it all worked. When I configured my laptop to add printer, one of the printer (hp deskjet 3900) wasn’t listet in add printer wizard. So But, when I used other laptop, the printer was listed.
    would u like to explain me this case?

    Thanks a lot :D

    • Hi Rini,

      “When I configured my laptop to add printer, one of the printer (hp deskjet 3900) wasn’t listet in add printer wizard.”

      I assume you mean when you’re trying to add the printer on your PC.

      In other words, the printer shows up within CUPs.

      Are you sure you did Step 5 above correctly?

      If the issue is something more than this, I’m not sure if I can help. I now only have network printers, and don’t use CUPs or OpenWRT anymore.

      Thanks,

      Matt

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