https://github.com/huawenyu/curl_tunnel

A tool proxy tunnel using libcurl, which forces another command tunneled over a proxy. Fork https://repo.or.cz/w/curltunnel.git
https://github.com/huawenyu/curl_tunnel

curl libcurl proxy tunnel

Last synced: 23 days ago
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A tool proxy tunnel using libcurl, which forces another command tunneled over a proxy. Fork https://repo.or.cz/w/curltunnel.git

• Host: GitHub
• URL: https://github.com/huawenyu/curl_tunnel
• Owner: huawenyu
• License: mit
• Created: 2022-09-28T06:05:37.000Z (about 2 years ago)
• Default Branch: master
• Last Pushed: 2022-10-27T20:11:02.000Z (about 2 years ago)
• Last Synced: 2024-09-30T02:40:59.311Z (about 1 month ago)
• Topics: curl, libcurl, proxy, tunnel
• Language: C
• Homepage:
• Size: 10.7 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# curl_tunnel

A proxy tunnel using libcurl, fork https://repo.or.cz/w/curltunnel.git

# Usage

	echo hello | curltunnel -p ":" -u "a:a" -d "www.google.com:80"

# Build

## ubuntu

Choose one mode to install libcurl, depending on which we want to use for SSL:

+ gnutls,

+ openssl,

+ nss,

```bash

	$ sudo apt-get install libcurl4-gnutls-dev

	$ sudo apt-get install libcurl4-openssl-dev

	$ sudo apt-get install libcurl4-nss-dev

	$ make

```

# Design

Using iptable redirect the outbout traffic to local-in,

  then `curltunnel` listen on this local-in port as the dummy-server side,

  bypass the following traffic after setup tunnel to proxy/network-device by HTTP/HTTPS.

Firstly, let check iptables works:

    (LinuxPC) $ sudo iptables -t nat -A OUTPUT -p tcp --dport 54321 -j DNAT --to-destination 127.0.0.1:4444

    (LinuxPC-shell_1) $ netcat -l 4444                  ### setup local-in listen

    (LinuxPC-shell_2) $ netcat www.google.com 54321     ### try to connect outboud public server

    ... try to input something  ...

    (LinuxPC-shell_1) $

    ... Will show up the string input by shell_2 ...

```C:  Get the orginal server's IP address

    // Get the original server address

    struct sockaddr_in addr;

    socklen_t addr_sz = sizeof(addr);

    memset(&addr, 0, addr_sz);

    addr.sin_family = AF_INET;

    getsockopt(clientfd, SOL_IP, 80/*SO_ORIGINAL_DST*/, &addr, &addr_sz);

    printf("The original server address is %s\n", inet_ntoa(addr.sin_addr));

```