Awesome
esp32ppp
Micropython idf3 official binary
It doesn't have IP forwarding so we will use socks to connect. ESP32 must first active PPP and then connect to WiFi network. If PPP is started after WiFi, it will spoil WiFi routing.
To verify that ESP32 WiFi internet routing is still working, we can check by trying to set NTP time. If WiFi internet (still) works it will just give prompt, if not some some error will appear.
from ntptime import settime
settime()
ESP32 PPP has limited time (about 10 seconds) when it tries to connect with linux and then it will give up. PPP must be started before WiFi, otherwise if PPP is started after, it will spoil WiFi routing. For the same reason PPP can't be restarted to retry, so we have one chance in a time window to connect.
In practice we power up board with autostart scripts. ESP32 autostart script first waits 50 seconds and then starts ppp, wifi, uftpd, socks, in this order. Saxonsoc linux bistream is writen in flash, boots about 50 seconds and then it runs autostart scripts from "/etc/init.d/". Script "S30ppp" starts pppd daemon before ethernet networking.
Copy "main.py", "ppptun.py" and other dependencies to root of ESP32 micropython internal flash disk. Copy "S30ppp" to "/etc/init.d/S30ppp" at saxonsoc linux. Few seconds after saxonsoc boots, you should see them connected with ppp interface:
ifconfig
ppp0 Link encap:Point-to-Point Protocol
inet addr:10.0.5.2 P-t-P:10.0.5.1 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:5 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:90 (90.0 B) TX bytes:58 (58.0 B)
Try getting something from internet IP with curl:
curl --proxy socks5://10.0.5.1:1080 http://87.248.100.216/index.html
... webpage should be printed to stdout ...
Using the named host should also work:
curl --proxy socks5h://10.0.5.1:1080 http://www.google.com/index.html
Micropython compiled with IP forward
Paul Ruiz recompiled micropython with IP forwarding enabled
#define IP_FORWARD 1
Load this to ESP32 first.
Linux can connect to secondary serial port of ESP32 where PPP traffic will be active.
output wire wifi_gpio16, // RX input on ESP32
input wire wifi_gpio17, // TX output on ESP32
This will activate PPP:
>>> import ppptun
>>> p=ppptun.ppptun()
Now we have cca 15 seconds to connect. ESP32 should start PPP packets on serial line which look like this:
~�}#�!}!}!} }4}"}&} } } } }%}&y��#}'}"}(}"b\~
run this command as linux root user (prepare it in a script):
stty -F /dev/ttySL0 raw
pppd /dev/ttySL0 115200 10.0.5.2:10.0.5.1 noauth local debug dump defaultroute nocrtscts nodetach
it should print something like this as successful connect:
sent [LCP ProtRej id=0x2 80 57 01 01 00 0e 01 0a 19 48 30 02 45 eb 9a 9a]
rcvd [IPCP ConfAck id=0x1 <compress VJ 0f 01> <addr 10.0.5.2>]
rcvd [IPCP ConfReq id=0x2 <compress VJ 0f 01> <addr 0.0.0.0>]
sent [IPCP ConfNak id=0x2 <addr 10.0.5.1>]
rcvd [IPCP ConfReq id=0x3 <compress VJ 0f 01> <addr 10.0.5.1>]
sent [IPCP ConfAck id=0x3 <compress VJ 0f 01> <addr 10.0.5.1>]
not replacing default route to enp2s0 [192.168.18.254]
local IP address 10.0.5.2
remote IP address 10.0.5.1
If ESP32 is running FTP server you can connect there:
ftp 10.0.5.1
Connected to 10.0.5.1.
220 Hello, this is the ESP8266.
230 Logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
200 OK
150 Directory listing:
-rw-r--r-- 1 owner group 137 Jan 1 00:01 boot.py
-rw-r--r-- 1 owner group 14 Jan 1 07:38 webrepl_cfg.py
...
More details on Linux PPP setup
ESP32 will route PPP traffic but can't do NAT so some static routes are required for the computer connected to ESP32 PPP:
route add default gw 10.0.5.1
DNS can be set by editing file "/etc/resolv.conf"
domain lan
search lan
nameserver 192.168.28.254
and route for the other computer on WiFi network which needs to know how to return packet back to ESP32. Assume ESP32 has been assigned WiFi address 192.168.28.118:
route add -host 10.0.5.2 gw 192.168.28.118
remote linux on LAN can be used to provide internet access by activating its masquerade option:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables --table nat --append POSTROUTING -s 10.0.5.2 -j MASQUERADE
iptables --append FORWARD -d 10.0.5.2 -j ACCEPT
ESP32 has no NAT but linux can use IPIP or GRE kernel module to get full featured internet access. Howto is here:
SOCKS server
KOST released socks server for micropython that means you can tunnel any SOCKS5 connection over ESP32 since micropython does not come with NAT support, that means you can go to the internet over ESP32 using SOCKS server. Installation is simple if you have connected ESP32 already to the internet: You have to run this on ulx3s repl shell:
import upip
upip.install('micropython-socks')
and then you can just simply say:
import socks
socks.start()
it will start listening on 0.0.0.0:1080 for SOCKS5 connections. Then you can simply from SaxonSoc test it with the following (or any other host):
curl --socks5 10.0.5.1:1080 http://87.248.100.216/index.html