mirror of
https://github.com/zhigang1992/cow.git
synced 2026-01-12 22:46:29 +08:00
156 lines
3.8 KiB
Go
156 lines
3.8 KiB
Go
package main
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import (
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"bytes"
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"fmt"
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"io"
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"os"
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"text/template"
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"time"
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)
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var errPageRawTmpl = `<!DOCTYPE html>
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<html>
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<head> <title>COW Proxy</title> </head>
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<body>
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<h1>{{.H1}}</h1>
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{{.Msg}}
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{{.Form}}
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<hr />
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Generated by <i>COW</i> at {{.T}}
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</body>
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</html>
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`
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var blockedFormRawTmpl = `<p></p>
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<b>Refresh to retry</b> or add <b>{{.Domain}}</b> to
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<form action="http://{{.ProxyAddr}}/blocked" method="get">
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<input type="hidden" name="host" value={{.Host}}>
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<b>blocked sites</b>
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<input type="submit" name="submit" value="blocked">
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</form>
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`
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var directFormRawTmpl = `<form action="http://{{.ProxyAddr}}/direct" method="get">
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<input type="hidden" name="host" value={{.Host}}>
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<b>direct accessible sites</b>
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<input type="submit" name="submit" value="direct">
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</form>
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`
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// Do not end with "\r\n" so we can add more header later
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var headRawTmpl = "HTTP/1.1 {{.CodeReason}}\r\n" +
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"Connection: keep-alive\r\n" +
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"Cache-Control: no-cache\r\n" +
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"Pragma: no-cache\r\n" +
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"Content-Type: text/html\r\n" +
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"Content-Length: {{.Length}}\r\n"
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var errPageTmpl, headTmpl, blockedFormTmpl, directFormTmpl *template.Template
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func init() {
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var err error
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if headTmpl, err = template.New("errorHead").Parse(headRawTmpl); err != nil {
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fmt.Println("Internal error on generating error head template")
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os.Exit(1)
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}
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if errPageTmpl, err = template.New("errorPage").Parse(errPageRawTmpl); err != nil {
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fmt.Println("Internal error on generating error page template")
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os.Exit(1)
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}
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if blockedFormTmpl, err = template.New("blockedForm").Parse(blockedFormRawTmpl); err != nil {
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fmt.Println("Internal error on generating blocked form template")
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os.Exit(1)
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}
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if directFormTmpl, err = template.New("directForm").Parse(directFormRawTmpl); err != nil {
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fmt.Println("Internal error on generating direct form template")
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os.Exit(1)
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}
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}
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func genErrorPage(h1, msg, form string) (string, error) {
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var err error
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data := struct {
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H1 string
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Msg string
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Form string
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T string
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}{
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h1,
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msg,
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form,
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time.Now().Format(time.ANSIC),
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}
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buf := new(bytes.Buffer)
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err = errPageTmpl.Execute(buf, data)
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return buf.String(), err
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}
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func sendPageGeneric(w io.Writer, codeReason, h1, msg, form, addHeader string) {
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page, err := genErrorPage(h1, msg, form)
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if err != nil {
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errl.Println("Error generating error page:", err)
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return
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}
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data := struct {
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CodeReason string
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Length int
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}{
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codeReason,
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len(page),
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}
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buf := new(bytes.Buffer)
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if err := headTmpl.Execute(buf, data); err != nil {
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errl.Println("Error generating error page header:", err)
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return
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}
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buf.WriteString(addHeader)
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buf.WriteString("\r\n")
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buf.WriteString(page)
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w.Write(buf.Bytes())
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}
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func sendErrorPage(w io.Writer, codeReason, h1, msg string) {
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sendPageGeneric(w, codeReason, "[Error] "+h1, msg, "", "")
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}
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func sendRedirectPage(w io.Writer, location string) {
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sendPageGeneric(w, "302 Found", "Domain added to blocked list", "Redirect to "+location,
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"", fmt.Sprintf("Location: %s\r\n", location))
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}
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func sendBlockedErrorPage(c *clientConn, codeReason, h1, msg string, r *Request) {
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// If host is IP or in always DS, we can't add it to blocked or direct domain list. Just
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// return ordinary error page.
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h, _ := splitHostPort(r.URL.Host)
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if hostIsIP(r.URL.Host) || domainSet.isHostInAlwaysDs(h) {
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sendErrorPage(c, codeReason, h1, msg)
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return
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}
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data := struct {
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ProxyAddr string
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Host string
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Domain string
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}{
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c.proxy.addr,
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h,
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host2Domain(r.URL.Host),
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}
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buf := new(bytes.Buffer)
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if err := blockedFormTmpl.Execute(buf, data); err != nil {
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errl.Println("Error generating blocked form:", err)
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return
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}
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if !domainSet.isHostDirect(h) {
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if err := directFormTmpl.Execute(buf, data); err != nil {
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errl.Println("Error generating direct form:", err)
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return
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}
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}
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sendPageGeneric(c, codeReason, "[Error] "+h1, msg, buf.String(), "")
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}
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