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saga420/fw.go

Created August 28, 2022 10:07
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  1. saga420 created this gist Aug 28, 2022.
    81 changes: 81 additions & 0 deletions fw.go
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,81 @@
    package main

    import (
    "github.com/gin-gonic/gin"
    "net"
    "net/http"
    "os/exec"
    )

    var privateNetworks []*net.IPNet

    func init() {
    for _, cidr := range []string{
    // RFC 1918: private IPv4 networks
    "10.0.0.0/8",
    "172.16.0.0/12",
    "192.168.0.0/16",
    // RFC 4193: IPv6 ULAs
    "fc00::/7",
    // RFC 6598: reserved prefix for CGNAT
    "100.64.0.0/10",
    } {
    _, subnet, _ := net.ParseCIDR(cidr)
    privateNetworks = append(privateNetworks, subnet)
    }
    }

    // IsPrivateAddress returns whether an IP address belongs to the LAN.
    func IsPrivateAddress(ip net.IP) bool {
    for _, network := range privateNetworks {
    if network.Contains(ip) {
    return true
    }
    }
    return false
    }

    func main() {
    r := gin.Default()
    r.GET("/a", func(c *gin.Context) {
    ip := net.ParseIP(c.RemoteIP())
    if IsPrivateAddress(ip) == true {
    c.JSON(http.StatusOK, gin.H{
    "e": "private",
    })
    return
    }
    s, e := exec.Command("/usr/sbin/ufw", "allow", "from", ip.String(), "to", "any").Output()
    if e != nil {
    c.JSON(http.StatusOK, gin.H{
    "ri": e.Error(),
    })
    return
    }
    c.JSON(http.StatusOK, gin.H{
    "ri": ip.String(),
    "s": string(s),
    "ci": c.ClientIP(),
    })
    return
    })
    r.GET("/d", func(c *gin.Context) {
    ip := net.ParseIP(c.RemoteIP())
    if IsPrivateAddress(ip) == true {
    c.JSON(http.StatusOK, gin.H{
    "e": "private",
    })
    return
    }
    exec.Command("/usr/sbin/ufw", "--force", "reset").Output()
    exec.Command("/usr/sbin/ufw", "allow", "80").Output()
    exec.Command("/usr/sbin/ufw", "allow", "22").Output()
    exec.Command("/usr/sbin/ufw", "--force", "enable").Output()
    c.JSON(http.StatusOK, gin.H{
    "ri": ip.String(),
    "ci": c.ClientIP(),
    })
    return
    })
    r.Run(":80")
    }