optional public IP fetching

Overlord-Client/cmd/agent/config/config.go

@@ -32,6 +32,7 @@ var DefaultAgentToken = ""
 var DefaultBuildTag = ""
 var DefaultSleepSeconds = "0"
 var DefaultCriticalProcess = "false"
+var DefaultFetchPublicIP = "false"
 
 const settingsFile = "config/settings.json"
 const serverIndexFile = "config/server_index.json"
@@ -72,6 +73,7 @@ type Config struct {
 	AgentToken            string
 	BuildTag              string
 	SleepSeconds          int
+	FetchPublicIP         bool
 }
 
 func Load() Config {
@@ -169,6 +171,11 @@ func Load() Config {
 
 	criticalProcess := strings.ToLower(DefaultCriticalProcess) == "true"
 
+	fetchPublicIP := isTruthy(DefaultFetchPublicIP)
+	if v := strings.TrimSpace(os.Getenv("OVERLORD_FETCH_PUBLIC_IP")); v != "" {
+		fetchPublicIP = isTruthy(v)
+	}
+
 	tlsInsecureSkipVerify := true
 	if v := strings.ToLower(strings.TrimSpace(os.Getenv("OVERLORD_TLS_INSECURE_SKIP_VERIFY"))); v != "" {
 		tlsInsecureSkipVerify = v == "true" || v == "1" || v == "yes"
@@ -215,6 +222,7 @@ func Load() Config {
 		AgentToken:            agentToken,
 		BuildTag:              strings.TrimSpace(DefaultBuildTag),
 		SleepSeconds:          parseSleepSeconds(DefaultSleepSeconds),
+		FetchPublicIP:         fetchPublicIP,
 	}
 }
 

Overlord-Client/cmd/agent/config/public_ip.go

@@ -0,0 +1,39 @@
+//go:build fetch_public_ip
+
+package config
+
+import (
+	"encoding/json"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"time"
+)
+
+func FetchPublicIPAddress() string {
+	client := &http.Client{Timeout: 5 * time.Second}
+	resp, err := client.Get("https://api.ipify.org?format=json")
+	if err != nil {
+		return ""
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return ""
+	}
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 256))
+	if err != nil {
+		return ""
+	}
+	var payload struct {
+		IP string `json:"ip"`
+	}
+	if err := json.Unmarshal(body, &payload); err != nil {
+		return ""
+	}
+	ip := strings.TrimSpace(payload.IP)
+	if net.ParseIP(ip) == nil {
+		return ""
+	}
+	return ip
+}

Overlord-Client/cmd/agent/config/public_ip_stub.go

@@ -0,0 +1,5 @@
+//go:build !fetch_public_ip
+
+package config
+
+func FetchPublicIPAddress() string { return "" }

Overlord-Client/cmd/agent/session.go

@@ -653,6 +653,9 @@ func runSession(ctx context.Context, cancel context.CancelFunc, conn *websocket.
 	hello.Elevation = sysinfo.Elevation()
 	hello.Permissions = sysinfo.DarwinPermissions()
 	hello.HostArch = sysinfo.HostArch()
+	if cfg.FetchPublicIP {
+		hello.PublicIP = config.FetchPublicIPAddress()
+	}
 
 	if err := wire.WriteMsg(ctx, env.Conn, hello); err != nil {
 		return fmt.Errorf("send hello: %w", err)

Overlord-Client/cmd/agent/wire/protocol.go

@@ -23,6 +23,7 @@ type Hello struct {
 	IsAdmin     bool            `msgpack:"isAdmin,omitempty"`
 	Elevation   string          `msgpack:"elevation,omitempty"`
 	Permissions map[string]bool `msgpack:"permissions,omitempty"`
+	PublicIP    string          `msgpack:"publicIP,omitempty"`
 }
 
 type EnrollmentChallenge struct {