Some problems in usage part on RT-AC86U

[BonnieLi1]

Hi, When I operated on Asus rt-ac86u as instruction suggests, I met the following problems.

1. After interface is up, running admin@RT-AC86U:/jffs# ./nexutil -Ieth6 -s500 -b -l34 -vm+IBEQGIAgAAESIzRFWqu6q7q rsAAAAAAAAAAAAAAAAAAA== the error shows: __nex_driver_io: error However, when running the code without -s500, the error disappears. I have no idea...

2. Does anyone know if I need to download the tcpdump in RT-AC86U? Since it shows -sh: tcpdump: not found

Thanks for kindly reading and reply!!!!!

[jlinktu]

Hi,

1. make sure the patched dhd.ko is loaded, dmesg should show a line containing 10.10.122.20 (nexmon.org/csi when you omit -s500, nexutil won't do anything -> no error

2. one option is to cross compile tcpdump for the rt-ac86u from the https://github.com/RMerl/asuswrt-merlin.ng repository using the https://github.com/RMerl/am-toolchains toolchain, tested on a x86_64 linux host: a) clone the am-toolchains repo and do exports and path settings according to the readme instructions for bcm-hnd b) clone the asuswrt-merlin.ng repo, change directory to release/src/router/tcpdump-4.4.0, then:

   CC=aarch64-linux-gcc AR=aarch64-linux-ar RANLIB=aarch64-linux-ranlib AS=aarch64-linux-as LD=aarch64-linux-ld NM=aarch64-linux-nm ac_cv_linux_vers=2 CFLAGS=-static CPPFLAGS=-static LDFLAGS=-static ./configure --host=x86_64-unknown-linux-gnu && make

[BonnieLi1]

Hi,

1. make sure the patched dhd.ko is loaded, `dmesg` should show a line containing `10.10.122.20 (nexmon.org/csi`
   when you omit _-s500_, nexutil won't do anything -> no error

2. one option is to cross compile tcpdump for the rt-ac86u from the https://github.com/RMerl/asuswrt-merlin.ng repository using the https://github.com/RMerl/am-toolchains toolchain, tested on a x86_64 linux host:
   a) clone the am-toolchains repo and do exports and path settings according to the readme instructions for bcm-hnd
   b) clone the asuswrt-merlin.ng repo, change directory to `release/src/router/tcpdump-4.4.0`, then:
   ```
   CC=aarch64-linux-gcc AR=aarch64-linux-ar RANLIB=aarch64-linux-ranlib AS=aarch64-linux-as LD=aarch64-linux-ld NM=aarch64-linux-nm ac_cv_linux_vers=2 CFLAGS=-static CPPFLAGS=-static LDFLAGS=-static ./configure --host=x86_64-unknown-linux-gnu && make
   ```

Thanks for your kindly replying!!!! @jlinktu I can ensure that dhd.ko has loaded. So according to your reply, I run dmesg. However, it showed the following message: dhd_prot_ioctl: status ret value is -4 CONSOLE: 346239.493 wl0: wlc_scan_request_ex, can not scan while driver is down CONSOLE: 346239.493 wl0: wlc_scan_request_ex, can not scan due to error -4

May I know how to fix it? Thanks a lot!!!

[jlinktu]

Also make sure the interface you want to use is up:

wl -i <interface> up
wl -i <interface> radio on
ifconfig <interface> up

[BonnieLi1]

Thanks for your reply again!!! @jlinktu Now it did not display the driver error anymore!! However, when I cross compile tcpdump and operate as you said, it shows the error:

configure: error: C compiler cannot create executables

See `config.log' for more details

And log displays:

./configure: line 2704: aarch64-linux-gcc: command not found

Since I haven't done this kind of compiling before, I have no idea about it. Thanks a lot!!! Sorry for taking your time!!!

[jlinktu]

This is basically a repetition of my first response but with all required commands easy to follow. From a directory of your choice clone the toolchain:

git clone https://github.com/RMerl/am-toolchains.git

add the toolchain to your environment (this is only temporary):

export PATH=$PWD/am-toolchains/brcm-arm-hnd/crosstools-aarch64-gcc-5.3-linux-4.1-glibc-2.22-binutils-2.25/usr/bin:$PATH
export LD_LIBRARY_PATH=$PWD/am-toolchains/brcm-arm-hnd/crosstools-aarch64-gcc-5.3-linux-4.1-glibc-2.22-binutils-2.25/lib:$LD_LIBRARY_PATH

Proceed by cloning the source code and compiling libpcap (forgot about that earlier) and tcpdump (step 2b from my first response):

git clone https://github.com/RMerl/asuswrt-merlin.ng.git
cd asuswrt-merlin.ng/release/src/router/libpcap
CC=aarch64-linux-gcc AR=aarch64-linux-ar RANLIB=aarch64-linux-ranlib AS=aarch64-linux-as LD=aarch64-linux-ld NM=aarch64-linux-nm ./configure --host=x86_64-unknown-linux-gnu --with-pcap=linux && make
cd ../tcpdump-4.4.0
CC=aarch64-linux-gcc AR=aarch64-linux-ar RANLIB=aarch64-linux-ranlib AS=aarch64-linux-as LD=aarch64-linux-ld NM=aarch64-linux-nm ac_cv_linux_vers=2 CFLAGS=-static CPPFLAGS=-static LDFLAGS=-static ./configure --host=x86_64-unknown-linux-gnu && make

[yujianyuanhaha]

Hello, I also met the issue that at final step, the tool tcpdump is not found on RT-AC86 Router, did you finally fixed that? @BonnieLi1

however, this tool does exist on ubuntu machine at /usr/sbin/tcpdump, unfortunately, we are supposed to execute this tool Usage: step 6 on RT-AC86 Router.

Thanks for @jlinktu answer, I did follow your instruction and the compile pass, but when I ssh to the RT-AC86, i still did not found tcpdump installed.

Best Regards

---

[update] I later figure out nexutil is cross compile then scp copy, hence tcpdump can be scp in similiar way.

thanks @jlinktu

[tweigel-dev]

@zeroby0 I just retried the cross-compiling of nexon if this works currently and it is. But the crosscompilation of tcpdump fails at the crosscomplie of LibPCAP with the same error discribed at #123. I did everything within sudo su and start at step one at the bcm4366c0 tutorial of nexmoncsi and continue with the extention for tcp dump discribed here: #123

gcc --version --> 7.5.0

If I configure the LibPCAP without the crosscompilation environments everything works perfectly but obviously with the output is x86

I'am running out of ideas. I Will try to cross compile it at an arm based environment like pi3.

[zeroby0]

I don't know why that's happening. What does the log file say? There should be a log folder with log files. Has g++ been installed and source setup_env.sh been run?

Here is the tcpdump executable I compiled. You can extract it and scp to /jffs/ and it should run.

tcpdump.zip

[tweigel-dev]

Nice it works. Thanks! It would be great if we can deliver the nexutil and tcpdump as bin for the asus at this repo, isn't it?

[zeroby0]

Great idea! Those and dhd.ko. Would save a great deal of time for people.