v0.2.0

ADDED:
* The ability to show both IPv4 and IPv6 addresses (if the client has
  dual-stack and either the server does as well or a separate ClientInfo
  is running on the "other" net family).

TODO

@@ -3,5 +3,3 @@
 - also link to https://www.useragentstring.com/
 -- or maybe https://www.whatsmyua.info/
 -- see https://www.useragentstring.com/pages/api.php
-- note that though lynx and elinks are "graphical", links is considered text. w3m is considered graphical.
-- fix the text/plain issue for the json (et. al.) renderer

_extras/clientinfo.env

@@ -34,3 +34,22 @@
 # The GID or group name of the group to chown the socket directory to.
 # Uses the primary group of the runtime user if not specified.
 #CINFO_DGRP=http
+
+# If specified, IPv4 clients can have their IPv6 address detected
+# by using this URL (e.g. 'https://c6.r00t2.io/').
+# It is expected that this URL is also serving ClientInfo.
+#CINFO_V6U='https://c6.r00t2.io/'
+
+# If specified, IPv6 clients can have their IPv4 address detected
+# by using this URL (e.g. 'https://c4.r00t2.io/').
+# It is expected that this URL is also serving ClientInfo.
+#CINFO_V4U='https://c4.r00t2.io/'
+
+# Specify additional/explicit CORS origin(s).
+# If you're using -4/--ipv4/$CINFO_V4U and/or
+# -6/--ipv6/$CINFO_V6U, they will be added
+# automatically but you should add any
+# dual-stack domains that serve ClientInfo here,
+# separated by commas.
+# (e.g. 'https://c.r00t2.io'
+#CINFO_CORS='https://c.r00t2.io'

args/types.go

@@ -1,7 +1,7 @@
 package args
 
 import (
-	`io/fs`
+	"io/fs"
 )
 
 type Args struct {
@@ -12,11 +12,14 @@ type Args struct {
 	SockDirMode   fs.FileMode `env:"CINFO_DMODE" short:"M" long:"dmode" default:"0o0700" description:"If using a UDS, attempt to set the directory containing the socket to use this permission. This should probably be either 0o0700 or 0o0770."`
 	SockGrp       *string     `env:"CINFO_FGRP" short:"g" long:"fgroup" description:"If specified and using a UDS, attempt to set the socket to this GID/group name. (If unspecified, the default is current user's primary group.)"`
 	SockDirGrp    *string     `env:"CINFO_DGRP" short:"G" long:"dgroup" description:"If specified and using a UDS, attempt to set the directory containing the socket to this GID/group name. (If unspecified, the default is current user's primary group.)"`
+	V4Url         *string     `env:"CINFO_V4U" short:"4" long:"ipv4" description:"If specified, IPv6 clients can have their IPv4 address detected by using this URL (e.g. 'https://c4.r00t2.io/').\nIt is expected that this URL is also serving ClientInfo." validate:"omitempty,url"`
+	V6Url         *string     `env:"CINFO_V6U" short:"6" long:"ipv6" description:"If specified, IPv4 clients can have their IPv6 address detected by using this URL (e.g. 'https://c6.r00t2.io/').\nIt is expected that this URL is also serving ClientInfo." validate:"omitempty,url"`
+	CORS          []string    `env:"CINFO_CORS" short:"c" long:"cors" description:"Specify additional/explicit CORS origin(s). If you're using -4/--ipv4 and/or -6/--ipv6, they will be added automatically but you should add any dual-stack domains that serve ClientInfo here (e.g. '--cors https://r00t2.io'"`
 	Listen        ListenArgs  `positional-args:"true"`
 }
 
 type ListenArgs struct {
-	Listen string `env:"CINFO_URI" positional-arg-name:"LISTEN_URI" default:"unix:///var/run/clientinfo/fcgi.sock" description:"The specification to listen on.\nIf the scheme is 'unix', a FastCGI UDS/IPC socket is used (default); any host, query parameters, etc. component is ignored and the URI path is used to specify the socket.\nIf 'tcp', a FastCGI socket over TCP is opened on the <host:port>.\nIf 'http', an HTTP listener is opened on the <host:port>; any path, query parameters, etc. components are ignored.\nHTTPS is unsupported; terminate with a reverse proxy. All other schemes will cause a fatal error.\nThe default is 'unix:///var/run/clientinfo/fcgi.sock'." validate:"required,uri"`
+	Listen string `env:"CINFO_URI" positional-arg-name:"LISTEN_URI" default:"unix:///var/run/clientinfo/fcgi.sock" description:"The specification to listen on.\nIf the scheme is 'unix', a FastCGI UDS/IPC socket is used (default); any host, query parameters, etc. component is ignored and the URI path is used to specify the socket.\nIf 'tcp', a FastCGI socket over TCP is opened on the <host:port>.\nIf 'http', an HTTP listener is opened on the <host:port>; any path, query parameters, etc. components are ignored.\nHTTPS is unsupported; terminate with a reverse proxy. All other schemes will cause a fatal error." validate:"required,uri"`
 }
 
 type UdsPerms struct {

go.mod

@@ -1,30 +1,30 @@
 module r00t2.io/clientinfo
 
-go 1.23.3
+go 1.25.5
 
 require (
 	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
 	github.com/creasty/defaults v1.8.0
 	github.com/davecgh/go-spew v1.1.1
-	github.com/go-playground/validator/v10 v10.23.0
+	github.com/go-playground/validator/v10 v10.29.0
-	github.com/goccy/go-yaml v1.15.7
+	github.com/goccy/go-yaml v1.19.0
 	github.com/jessevdk/go-flags v1.6.1
 	github.com/mileusna/useragent v1.3.5
-	golang.org/x/mod v0.22.0
+	golang.org/x/mod v0.31.0
-	r00t2.io/goutils v1.7.1
+	r00t2.io/goutils v1.13.0
-	r00t2.io/sysutils v1.12.0
+	r00t2.io/sysutils v1.15.0
 )
 
 require (
+	github.com/coreos/go-systemd/v22 v22.6.0 // indirect
 	github.com/djherbis/times v1.6.0 // indirect
-	github.com/gabriel-vasile/mimetype v1.4.7 // indirect
+	github.com/gabriel-vasile/mimetype v1.4.12 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
-	golang.org/x/crypto v0.30.0 // indirect
+	golang.org/x/crypto v0.46.0 // indirect
-	golang.org/x/net v0.32.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
-	golang.org/x/sync v0.10.0 // indirect
+	golang.org/x/sys v0.39.0 // indirect
-	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/text v0.32.0 // indirect
-	golang.org/x/text v0.21.0 // indirect
 )

go.sum

@@ -1,27 +1,25 @@
 github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf h1:iW4rZ826su+pqaw19uhpSCzhj44qo35pNgKFGqzDKkU=
 github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
+github.com/coreos/go-systemd/v22 v22.6.0 h1:aGVa/v8B7hpb0TKl0MWoAavPDmHvobFe5R5zn0bCJWo=
+github.com/coreos/go-systemd/v22 v22.6.0/go.mod h1:iG+pp635Fo7ZmV/j14KUcmEyWF+0X7Lua8rrTWzYgWU=
 github.com/creasty/defaults v1.8.0 h1:z27FJxCAa0JKt3utc0sCImAEb+spPucmKoOdLHvHYKk=
 github.com/creasty/defaults v1.8.0/go.mod h1:iGzKe6pbEHnpMPtfDXZEr0NVxWnPTjb1bbDy08fPzYM=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/djherbis/times v1.6.0 h1:w2ctJ92J8fBvWPxugmXIv7Nz7Q3iDMKNx9v5ocVH20c=
 github.com/djherbis/times v1.6.0/go.mod h1:gOHeRAz2h+VJNZ5Gmc/o7iD9k4wW7NMVqieYCY99oc0=
-github.com/gabriel-vasile/mimetype v1.4.3 h1:in2uUcidCuFcDKtdcBxlR0rJ1+fsokWf+uqxgUFjbI0=
+github.com/gabriel-vasile/mimetype v1.4.12 h1:e9hWvmLYvtp846tLHam2o++qitpguFiYCKbn0w9jyqw=
-github.com/gabriel-vasile/mimetype v1.4.3/go.mod h1:d8uq/6HKRL6CGdk+aubisF/M5GcPfT7nKyLpA0lbSSk=
+github.com/gabriel-vasile/mimetype v1.4.12/go.mod h1:d+9Oxyo1wTzWdyVUPMmXFvp4F9tea18J8ufA774AB3s=
-github.com/gabriel-vasile/mimetype v1.4.7 h1:SKFKl7kD0RiPdbht0s7hFtjl489WcQ1VyPW8ZzUMYCA=
-github.com/gabriel-vasile/mimetype v1.4.7/go.mod h1:GDlAgAyIRT27BhFl53XNAFtfjzOkLaF35JdEG0P7LtU=
 github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
 github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
 github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
 github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
 github.com/go-playground/universal-translator v0.18.1/go.mod h1:xekY+UJKNuX9WP91TpwSH2VMlDf28Uj24BCp08ZFTUY=
-github.com/go-playground/validator/v10 v10.23.0 h1:/PwmTwZhS0dPkav3cdK9kV1FsAmrL8sThn8IHr/sO+o=
+github.com/go-playground/validator/v10 v10.29.0 h1:lQlF5VNJWNlRbRZNeOIkWElR+1LL/OuHcc0Kp14w1xk=
-github.com/go-playground/validator/v10 v10.23.0/go.mod h1:dbuPbCMFw/DrkbEynArYaCwl3amGuJotoKCe95atGMM=
+github.com/go-playground/validator/v10 v10.29.0/go.mod h1:D6QxqeMlgIPuT02L66f2ccrZ7AGgHkzKmmTMZhk/Kc4=
-github.com/goccy/go-yaml v1.15.7 h1:L7XuKpd/A66X4w/dlk08lVfiIADdy79a1AzRoIefC98=
+github.com/goccy/go-yaml v1.19.0 h1:EmkZ9RIsX+Uq4DYFowegAuJo8+xdX3T/2dwNPXbxEYE=
-github.com/goccy/go-yaml v1.15.7/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
+github.com/goccy/go-yaml v1.19.0/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
-github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
-github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/jessevdk/go-flags v1.6.1 h1:Cvu5U8UGrLay1rZfv/zP7iLpSHGUZ/Ou68T0iX1bBK4=
@@ -34,33 +32,20 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-golang.org/x/crypto v0.19.0 h1:ENy+Az/9Y1vSrlrvBSyna3PITt4tiZLf7sgCjZBX7Wo=
+golang.org/x/crypto v0.46.0 h1:cKRW/pmt1pKAfetfu+RCEvjvZkA9RimPbh7bhFjGVBU=
-golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
+golang.org/x/crypto v0.46.0/go.mod h1:Evb/oLKmMraqjZ2iQTwDwvCtJkczlDuTmdJXoZVzqU0=
-golang.org/x/crypto v0.30.0 h1:RwoQn3GkWiMkzlX562cLB7OxWvjH1L8xutO2WoJcRoY=
+golang.org/x/mod v0.31.0 h1:HaW9xtz0+kOcWKwli0ZXy79Ix+UW/vOfmWI5QVd2tgI=
-golang.org/x/crypto v0.30.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
+golang.org/x/mod v0.31.0/go.mod h1:43JraMp9cGx1Rx3AqioxrbrhNsLl2l/iNAvuBkrezpg=
-golang.org/x/mod v0.22.0 h1:D4nJWe9zXqHOmWqj4VMOJhvzj7bEZg4wEYa759z1pH4=
+golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
-golang.org/x/mod v0.22.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
+golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
-golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
-golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
-golang.org/x/net v0.32.0 h1:ZqPmj8Kzc+Y6e0+skZsuACbx+wzMgo5MQsJh9Qd6aYI=
-golang.org/x/net v0.32.0/go.mod h1:CwU0IoeOlnQQWJ6ioyFrfRuomB8GKF6KbYXZVyeXNfs=
-golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
-golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220615213510-4f61da869c0c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws=
+golang.org/x/sys v0.39.0 h1:CvCKL8MeisomCi6qNZ+wbb0DN9E5AATixKsvNtMoMFk=
-golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.39.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
+golang.org/x/text v0.32.0 h1:ZD01bjUt1FQ9WJ0ClOL5vxgxOI/sVCNgX1YtKwcY0mU=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/text v0.32.0/go.mod h1:o/rUWzghvpD5TXrTIBuJU77MTaN0ljMWE47kxGJQ7jY=
-golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
-golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
-golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
-golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-r00t2.io/goutils v1.7.1 h1:Yzl9rxX1sR9WT0FcjK60qqOgBoFBOGHYKZVtReVLoQc=
+r00t2.io/goutils v1.13.0 h1:103QR2eUu42TNF7h9r6YgahbSgRAJ8VtFxSzw9rMaXI=
-r00t2.io/goutils v1.7.1/go.mod h1:9ObJI9S71wDLTOahwoOPs19DhZVYrOh4LEHmQ8SW4Lk=
+r00t2.io/goutils v1.13.0/go.mod h1:/0M+6fW2VAgdtAvwGE9oNV259MoEZeJ84rLCZsxe8uI=
-r00t2.io/sysutils v1.1.1 h1:q2P5u50HIIRk6muCPo1Gpapy6sNT4oaB1l2O/C/mi3A=
+r00t2.io/sysutils v1.15.0 h1:FSnREfbXDhBQEO7LMpnRQeKlPshozxk9XHw3YgWRgRg=
-r00t2.io/sysutils v1.1.1/go.mod h1:Wlfi1rrJpoKBOjWiYM9rw2FaiZqraD6VpXyiHgoDo/o=
+r00t2.io/sysutils v1.15.0/go.mod h1:28qB0074EIRQ8Sy/ybaA5jC3qA32iW2aYLkMCRhyAFM=
-r00t2.io/sysutils v1.12.0 h1:Ce3qUOyLixE1ZtFT/+SVwOT5kSkzg5+l1VloGeGugrU=
-r00t2.io/sysutils v1.12.0/go.mod h1:bNTKNBk9MnUhj9coG9JBNicSi5FrtJHEM645um85pyw=

server/consts.go

@@ -24,7 +24,7 @@ const (
 	trueUaFieldStr  string = "Yes"
 	falseUaFieldStr string = "No"
 	dfltIndent      string = "  "
-	httpRealHdr     string = "X-ClientInfo-RealIP"
+	httpRealHdr     string = "X-ClientInfo-RealIP" // TODO: advise https://nginx.org/en/docs/http/ngx_http_realip_module.html NGINX module? Allow config for user-specified header?
 )
 
 var (
@@ -35,6 +35,8 @@ var (
 			Funcs(
 				template.FuncMap{
 					"getTitle": getTitle,
+					"getIpver": getIpver,
+					"safeUrl": safeUrl,
 				},
 			).ParseFS(tplDir, "tpl/*.tpl"),
 	)

server/funcs.go

@@ -46,6 +46,7 @@ func NewClient(uaStr string) (r *R00tClient, err error) {
 func NewServer(log logging.Logger, cliArgs *args.Args) (srv *Server, err error) {
 
 	var s Server
+	var origin string
 	var udsSockPerms args.UdsPerms
 
 	if log == nil {
@@ -62,6 +63,7 @@ func NewServer(log logging.Logger, cliArgs *args.Args) (srv *Server, err error)
 		args:       cliArgs,
 		mux:        http.NewServeMux(),
 		sock:       nil,
+		corsOrigins: nil,
 		reloadChan: make(chan os.Signal),
 		stopChan:   make(chan os.Signal),
 	}
@@ -73,6 +75,42 @@ func NewServer(log logging.Logger, cliArgs *args.Args) (srv *Server, err error)
 	s.mux.HandleFunc("/usage.html", s.handleUsage)
 	s.mux.HandleFunc("/favicon.ico", s.explicit404)
 
+	if cliArgs.CORS != nil && len(cliArgs.CORS) > 0 {
+		if s.corsOrigins == nil {
+			s.corsOrigins = make(map[string]struct{})
+		}
+		for _, origin = range cliArgs.CORS {
+			s.corsOrigins[strings.ToLower(origin)] = struct{}{}
+		}
+	}
+
+	if cliArgs.V4Url != nil {
+		if s.v4Url, err = url.Parse(*cliArgs.V4Url); err != nil {
+			s.log.Err("server.NewServer: Failed to parse IPv4 URI '%s': %v", *cliArgs.V4Url, err)
+			return
+		}
+		if s.corsOrigins == nil {
+			s.corsOrigins = make(map[string]struct{})
+		}
+		origin = strings.ToLower(fmt.Sprintf("%s://%s", s.v4Url.Scheme, s.v4Url.Host))
+		s.corsOrigins[origin] = struct{}{}
+	}
+	if cliArgs.V6Url != nil {
+		if s.v6Url, err = url.Parse(*cliArgs.V6Url); err != nil {
+			s.log.Err("server.NewServer: Failed to parse IPv6 URI '%s': %v", *cliArgs.V6Url, err)
+			return
+		}
+		if s.corsOrigins == nil {
+			s.corsOrigins = make(map[string]struct{})
+		}
+		origin = strings.ToLower(fmt.Sprintf("%s://%s", s.v6Url.Scheme, s.v6Url.Host))
+		s.corsOrigins[origin] = struct{}{}
+	}
+
+	if s.corsOrigins != nil {
+		s.log.Debug("server.NewServer: CORS origins: %#v", s.corsOrigins)
+	}
+
 	if s.listenUri, err = url.Parse(cliArgs.Listen.Listen); err != nil {
 		s.log.Err("server.NewServer: Failed to parse listener URI: %v", err)
 		return

server/funcs_page.go

@@ -4,6 +4,48 @@ import (
 	`fmt`
 )
 
+func (p *Page) AltURL() (altUrl string) {
+
+	if !p.HasAltURL() {
+		return
+	}
+
+	if p.Info.IP.Is4() {
+		altUrl = p.srv.v6Url.String()
+	} else if p.Info.IP.Is6() {
+		altUrl = p.srv.v4Url.String()
+	}
+
+	return
+}
+
+func (p *Page) AltVer() (altVer string) {
+
+	if !p.HasAltURL() {
+		return
+	}
+
+	if p.Info.IP.Is4() {
+		altVer = "v6"
+	} else if p.Info.IP.Is6() {
+		altVer = "v4"
+	}
+
+	return
+}
+
+func (p *Page) HasAltURL() (hasAlt bool) {
+
+	if p.Info == nil {
+		return
+	}
+
+	hasAlt = (p.Info.IP.Is4() && p.srv.v6Url != nil) ||
+		(p.Info.IP.Is6() && p.srv.v4Url != nil)
+
+	return
+}
+
 func (p *Page) RenderIP(indent uint) (s string) {
 
 	s = fmt.Sprintf("<a href=\"https://ipinfo.io/%s\">%s</a>", p.Info.IP.String(), p.Info.IP.String())

server/funcs_server.go

@@ -3,24 +3,24 @@ package server
 import (
 	`encoding/json`
 	`encoding/xml`
-	"errors"
+	`errors`
-	"fmt"
+	`fmt`
-	"net"
+	`net`
-	"net/http"
+	`net/http`
 	`net/http/fcgi`
-	"net/netip"
+	`net/netip`
-	"net/url"
+	`net/url`
-	"os"
+	`os`
-	"os/signal"
+	`os/signal`
-	"strings"
+	`strings`
-	"sync"
+	`sync`
 	`syscall`
 
-	sysd "github.com/coreos/go-systemd/daemon"
+	sysd `github.com/coreos/go-systemd/daemon`
-	"github.com/davecgh/go-spew/spew"
+	`github.com/davecgh/go-spew/spew`
 	`github.com/goccy/go-yaml`
 	`r00t2.io/clientinfo/version`
-	"r00t2.io/goutils/multierr"
+	`r00t2.io/goutils/multierr`
 )
 
 // Close cleanly closes any remnants of a Server. Stop should be used instead to cleanly shut down; this is a little more aggressive.
@@ -267,8 +267,10 @@ func (s *Server) explicit404(resp http.ResponseWriter, req *http.Request) {
 func (s *Server) handleDefault(resp http.ResponseWriter, req *http.Request) {
 
 	var err error
+	var ok bool
 	var page *Page
 	var uas []string
+	var origin string
 	var reqdMimes []string
 	var parsedUA *R00tClient
 	var nAP netip.AddrPort
@@ -280,13 +282,20 @@ func (s *Server) handleDefault(resp http.ResponseWriter, req *http.Request) {
 	var outerFmt string = mediaJSON
 
 	s.log.Debug("server.Server.handleDefault: Handling request:\n%s", spew.Sdump(req))
+	origin = req.Header.Get("Origin")
+	if s.corsOrigins != nil && len(s.corsOrigins) != 0 && origin != "" {
+		if _, ok = s.corsOrigins[origin]; ok {
+			resp.Header().Set("Access-Control-Allow-Origin", origin)
+			resp.Header().Add("Vary", "Origin")
+		}
+	}
 
 	resp.Header().Set("ClientInfo-Version", version.Ver.Short())
 
 	page = &Page{
 		Info: &R00tInfo{
 			Client:  nil,
-			IP:      nil,
+			IP:      netip.Addr{},
 			Port:    0,
 			Headers: XmlHeaders(req.Header),
 			Req:     req,
@@ -301,7 +310,7 @@ func (s *Server) handleDefault(resp http.ResponseWriter, req *http.Request) {
 	// First the client info.
 	remAddrPort = req.RemoteAddr
 	if s.isHttp && req.Header.Get(httpRealHdr) != "" {
-		// TODO: WHitelist explicit reverse proxy addr(s)?
+		// TODO: Whitelist explicit reverse proxy addr(s)?
 		remAddrPort = req.Header.Get(httpRealHdr)
 		req.Header.Del(httpRealHdr)
 	}
@@ -315,7 +324,7 @@ func (s *Server) handleDefault(resp http.ResponseWriter, req *http.Request) {
 			*/
 			err = nil
 		}
-		page.Info.IP = net.ParseIP(nAP.Addr().String())
+		page.Info.IP = nAP.Addr().Unmap()
 		page.Info.Port = nAP.Port()
 	}
 	if req.URL != nil {
@@ -547,6 +556,8 @@ func (s *Server) renderHTML(page *Page, resp http.ResponseWriter) (err error) {
 
 	var b []byte
 
+	page.srv = s
+
 	if page.RawFmt != nil {
 		switch *page.RawFmt {
 		case mediaHTML:

server/funcs_tpl.go

@@ -2,9 +2,22 @@ package server
 
 import (
 	`fmt`
+	`net/netip`
 	`strings`
+	`html/template`
 )
 
+func getIpver(a netip.Addr) (verStr string) {
+
+	if a.Is4() {
+		verStr = "v4"
+	} else if a.Is6() {
+		verStr = "v6"
+	}
+
+	return
+}
+
 func getTitle(subPage string) (title string) {
 
 	if subPage == "" || subPage == "index" {
@@ -16,3 +29,10 @@ func getTitle(subPage string) (title string) {
 
 	return
 }
+
+func safeUrl(urlStr string) (u template.URL) {
+
+	u = template.URL(urlStr)
+	
+	return
+}

server/tpl/meta.info.html.tpl

@@ -4,9 +4,35 @@
 {{- $linkico := "🔗" }}
 					<h2 id="client">Client/Browser Information<a href="#client">{{ $linkico }}</a></h2>
 					<p>
-						<b>Your IP Address is <i><a href="https://ipinfo.io/{{ $page.Info.IP.String }}">{{ $page.Info.IP.String }}</a></i>.</b>
+						<b>Your IP{{ getIpver $page.Info.IP }} Address is <i><a href="https://ipinfo.io/{{ $page.Info.IP.String }}">{{ $page.Info.IP.String }}</a></i>.</b>
 						<br/>
 						<i>You are connecting with port <b>{{ $page.Info.Port }}</b> outbound.</i>
+						{{- if $page.HasAltURL }}
+						<div id="alt_addr"></div>
+						<script>
+							async function fetchAltAddr() {
+								try {
+									const resp = await fetch('{{ safeUrl $page.AltURL }}', {
+										headers: {
+											'Accept': 'application/json'
+										}
+									});
+									if (resp.ok) {
+										const dat = await resp.json();
+										const addr = dat.ip;
+										const infoDiv = document.getElementById('alt_addr');
+										infoDiv.innerHTML = `
+						<i>You also have IP{{ $page.AltVer }} address <b><a href="https://ipinfo.io/${addr}">${addr}</a></b>.</i>
+						<br/>
+						<i>Try loading <b><a href="{{ $page.AltURL }}">{{ $page.AltURL }}</a></b> for more information.</i>`;
+										}
+								} catch (error) {
+									console.info('Did not fetch alternate address: ', error);
+								}
+							}
+							fetchAltAddr()
+						</script>
+						{{- end }}
 					</p>
 					{{- if $page.Raw }}
 					<h3 id="client_raw">Raw Block ({{ $page.RawFmt }})<a href="#client_raw">{{ $linkico }}</a></h3>

server/types.go

@@ -1,19 +1,22 @@
 package server
 
 import (
-	`encoding/xml`
+	"encoding/xml"
-	`net`
+	"net"
-	`net/http`
+	"net/http"
-	`net/url`
+	"net/netip"
-	`os`
+	"net/url"
+	"os"
 
-	`github.com/mileusna/useragent`
+	"github.com/mileusna/useragent"
-	`r00t2.io/clientinfo/args`
+	"r00t2.io/clientinfo/args"
-	`r00t2.io/goutils/logging`
+	"r00t2.io/goutils/logging"
 )
 
-type outerRenderer func(page *Page, resp http.ResponseWriter) (err error)
+type (
-type XmlHeaders map[string][]string
+	outerRenderer func(page *Page, resp http.ResponseWriter) (err error)
+	XmlHeaders    map[string][]string
+)
 
 // R00tInfo is the structure of data returned to the client.
 type R00tInfo struct {
@@ -22,7 +25,7 @@ type R00tInfo struct {
 	// Client is the UA/Client info, if any passed by the client.
 	Client []*R00tClient `json:"ua,omitempty" xml:"ua,omitempty" yaml:"Client/User Agent,omitempty"`
 	// IP is the client IP address.
-	IP net.IP `json:"ip" xml:"ip,attr" yaml:"Client IP Address"`
+	IP netip.Addr `json:"ip" xml:"ip,attr" yaml:"Client IP Address"`
 	// Port is the client's port number.
 	Port uint16 `json:"port" xml:"port,attr" yaml:"Client Port"`
 	// Headers are the collection of the request headers sent by the client.
@@ -84,6 +87,7 @@ type Page struct {
 	Indent string
 	// DoIndent indicates if indenting was enabled.
 	DoIndent bool
+	srv      *Server
 }
 
 type Server struct {
@@ -96,6 +100,9 @@ type Server struct {
 	doneChan    chan bool
 	stopChan    chan os.Signal
 	reloadChan  chan os.Signal
+	v4Url       *url.URL
+	v6Url       *url.URL
+	corsOrigins map[string]struct{}
 	isStopping  bool
 }