From a7cca80731d35ed4780a8e347287187504e0422b Mon Sep 17 00:00:00 2001
From: David Coles <david.coles@global.com>
Date: Mon, 24 Jun 2024 11:17:35 +0100
Subject: [PATCH] command channel for reattaching interfaces

---
 cmd/config.pl |  2 ++
 cmd/go.mod    |  2 +-
 cmd/go.sum    |  4 ++--
 cmd/main.go   | 17 ++++++++++++++++
 cmd/xvs.go    | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/cmd/config.pl b/cmd/config.pl
index 70d4866..fb84084 100755
--- a/cmd/config.pl
+++ b/cmd/config.pl
@@ -239,6 +239,8 @@ sub expect {
     my($expect) = @_;
     my @expect;
 
+    return [ 0 ] if $expect eq 'any';
+    
     foreach (split(/\s+/, $expect)) {
 	my @val;
 	
diff --git a/cmd/go.mod b/cmd/go.mod
index 392efaf..928bb0a 100644
--- a/cmd/go.mod
+++ b/cmd/go.mod
@@ -3,7 +3,7 @@ module vc5
 go 1.19
 
 require (
-	github.com/davidcoles/cue v0.1.1
+	github.com/davidcoles/cue v0.1.2
 	github.com/davidcoles/xvs v0.1.15
 	github.com/elastic/go-elasticsearch/v7 v7.17.10
 )
diff --git a/cmd/go.sum b/cmd/go.sum
index f56cd47..dc15fe6 100644
--- a/cmd/go.sum
+++ b/cmd/go.sum
@@ -1,5 +1,5 @@
-github.com/davidcoles/cue v0.1.1 h1:R2hG4gSVKuCj7UmTQGhZS/ZRmfDULqmA03uXwx7rgOg=
-github.com/davidcoles/cue v0.1.1/go.mod h1:26FTBytVHJ1XQWOGC+Cfnx4Q9xV8k1xr6K5uZ7s/EBw=
+github.com/davidcoles/cue v0.1.2 h1:UZnjl6ezaG7WC9iFbarB/+u7rDVa4aExSCx1ugtwMIU=
+github.com/davidcoles/cue v0.1.2/go.mod h1:26FTBytVHJ1XQWOGC+Cfnx4Q9xV8k1xr6K5uZ7s/EBw=
 github.com/davidcoles/xvs v0.1.15 h1:FJ5CN0VEqyoilK/R0Pvc51lKpLsOTqcstPilkkxgbZw=
 github.com/davidcoles/xvs v0.1.15/go.mod h1:NQg6Ob9zLr49qH3I6E6zqnGp4tVBu4cT/3vXUB2XA8w=
 github.com/elastic/go-elasticsearch/v7 v7.17.10 h1:TCQ8i4PmIJuBunvBS6bwT2ybzVFxxUhhltAs3Gyu1yo=
diff --git a/cmd/main.go b/cmd/main.go
index cc57c09..3c06475 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -63,6 +63,7 @@ func main() {
 	mp := flag.Bool("M", false, "Use multiprotocol extensions on loopback BGP") // experimental - may change
 	delay := flag.Uint("D", 0, "Delay between initialisaton of interfaces")     // experimental - may change
 	flows := flag.Uint("F", 0, "Set maximum number of flows")                   // experimental - may change
+	cmd_path := flag.String("C", "", "Command channel path")                    // experimental - may change
 
 	// Changing number of flows will only work on some kernels
 	// Not supported: 5.4.0-171-generic
@@ -148,6 +149,18 @@ func main() {
 		go bgpListener(l, logs.sub("bgp"))
 	}
 
+	var cmd_sock net.Listener
+
+	if *cmd_path != "" {
+		os.Remove(*cmd_path)
+
+		cmd_sock, err = net.Listen("unix", *cmd_path)
+
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
 	for _, i := range nics {
 		ethtool(i)
 	}
@@ -170,6 +183,10 @@ func main() {
 		log.Fatal("Couldn't start client: ", err)
 	}
 
+	if cmd_sock != nil {
+		go readCommands(cmd_sock, client, logs.sub("command"))
+	}
+
 	routerID := address.As4()
 
 	if *asn > 0 {
diff --git a/cmd/xvs.go b/cmd/xvs.go
index e4156e7..ce6ca67 100644
--- a/cmd/xvs.go
+++ b/cmd/xvs.go
@@ -32,6 +32,7 @@ import (
 	"net/netip"
 	"os"
 	"os/exec"
+	"regexp"
 	"sync/atomic"
 	"time"
 
@@ -367,3 +368,57 @@ func multicast_recv(c Client, address string) {
 		}
 	}
 }
+
+func readCommands(sock net.Listener, client Client, log *sub) {
+	// eg.: echo enp130s0f0 | socat - UNIX-CLIENT:/var/run/vc5
+
+	re := regexp.MustCompile(`\s+`)
+
+	for {
+		conn, err := sock.Accept()
+		if err != nil {
+			log.ERR("accept", err.Error())
+		} else {
+			go func() {
+				s := bufio.NewScanner(conn)
+
+				for s.Scan() {
+
+					line := s.Text()
+
+					var cmd []string
+
+					for _, s := range re.Split(line, -1) {
+						if s != "" {
+							cmd = append(cmd, s)
+						}
+					}
+
+					l := len(cmd)
+
+					if l < 1 {
+						continue
+					}
+
+					switch cmd[0] {
+					case "reattach":
+						if l != 2 {
+							fmt.Println("Usage: reattach <interface>")
+							continue
+						}
+
+						nic := cmd[1]
+						if err := client.ReattachBPF(nic); err != nil {
+							log.ERR(cmd[0], fmt.Sprintf("%s: %s\n", nic, err.Error()))
+						} else {
+							log.NOTICE(cmd[0], fmt.Sprintf("%s: OK\n", nic))
+						}
+
+					default:
+						log.ERR("unknown", fmt.Sprintf("Unknown command: %s", cmd[0]))
+					}
+				}
+			}()
+		}
+	}
+}