Replace (undocumented) "link-l3" option with argument for "link"

diff --git a/README.adoc b/README.adoc
index 5cc1b86e5f10ac2a80689b0bf654b25aaae1a508..1ec8238fd7c831d05e830c55f0c73d00054e2489 100644 (file)
--- a/README.adoc
+++ b/README.adoc
@@ -141,13 +141,15 @@ new interface "lo2".
 
 === Option "link"
 
-    "link" <node> <node> <net-name>
+    "link" <node> <node> <net-name> ["l3"]
 
-"link" creates (veth-)links between nodes. The IP addresses are taken from the
-given network name. /31 is used for IPv4- and /127 for IPv6-prefixes. The MAC
+"link" creates links between nodes. The IP addresses are taken from the given
+network name. /31 is used for IPv4- and /127 for IPv6-prefixes. The MAC
 address is not static and allocated by the kernel. The link is named after the
 node "on the other side". Multiple links can be created between two nodes. In
-this case "_2", "_3", etc. is appended to the interface name.
+this case "_2", "_3", etc. is appended to the interface name. By default veth
+interfaces are used, adding "l3" changes this to netkit which provide a
+layer-3 connection without needing ARP (requires kernel 6.7, iproute2 6.8).
 
 === Option "cmd"
 

diff --git a/ci/examples b/ci/examples
index 0a86b9321f40ffe45190a3f6d5d76d750d529ff8..ff5a73d227a39dfd70184f33d84b0eb428fe8ff4 100755 (executable)
--- a/ci/examples
+++ b/ci/examples
@@ -40,6 +40,14 @@ linux-network-namespace-labs down lab.conf
 test -z "$(ip netns)"
 test "$(cd /etc/netns; find)" = "." # directory empty
 
+cd "$examples/layer3"
+linux-network-namespace-labs up lab.conf
+ip netns exec r1 ip route add 3fff::1/128 dev r2
+ip netns exec r1 ping -c1 3fff::1
+linux-network-namespace-labs down lab.conf
+test -z "$(ip netns)"
+test "$(cd /etc/netns; find)" = "." # directory empty
+
 cd "$examples/podman-frr"
 ./run.sh
 wait_for_route r1 3fff::1

diff --git a/config.go b/config.go
index 66cefc07e6c5738c5dbdc13196e14988a18fc8a9..2773b8dacc4bba8289b6bafb80e423286a4e9ee5 100644 (file)
--- a/config.go
+++ b/config.go
@@ -93,11 +93,8 @@ func LoadConfig(path string) (*Config, error) {
                        usage = `"node" <name> [<loopback-net-name>...]`
                        err = parseConfigNode(&cfg, xs[1:])
                case "link":
-                       usage = `"link" <node> <node> <net-name>`
-                       err = parseConfigLink(&cfg, xs[1:], false)
-               case "link-l3":
-                       usage = `"link-l3" <node> <node> <net-name>`
-                       err = parseConfigLink(&cfg, xs[1:], true)
+                       usage = `"link" <node> <node> <net-name> ["l3"]`
+                       err = parseConfigLink(&cfg, xs[1:])
                case "cmd":
                        usage = `"cmd" <string-passed-to-sh-c>`
                        x := strings.TrimSpace(strings.TrimPrefix(l, "cmd"))
@@ -183,11 +180,20 @@ func parseConfigNode(cfg *Config, args []string) error {
        return nil
 }
 
-func parseConfigLink(cfg *Config, args []string, l3 bool) error {
-       if len(args) != 3 {
+func parseConfigLink(cfg *Config, args []string) error {
+       if len(args) != 3 && len(args) != 4 {
                return fmt.Errorf("invalid arguments")
        }
 
+       var l3 bool
+       if len(args) == 4 {
+               if args[3] == "l3" {
+                       l3 = true
+               } else {
+                       return fmt.Errorf("invalid arguments")
+               }
+       }
+
        n1 := cfg.Nodes[args[0]]
        if n1 == nil {
                return fmt.Errorf("node %q does not exist", args[0])

diff --git a/examples/layer3/README.adoc b/examples/layer3/README.adoc
new file mode 100644 (file)
index 0000000..9cf9e04
--- /dev/null
+++ b/examples/layer3/README.adoc
@@ -0,0 +1,40 @@
+= README
+
+Proof of concept lab with two nodes (routers) using a layer-3 link which
+doesn't require ARP.
+
+You need kernel 6.7 and iproute2 6.8.
+
+Then start the lab (as root) with:
+
+    # ./run.sh
+
+To enter the node use:
+
+    # ip netns exec r1 sh
+
+    # ip route add 3fff::1/128 dev r2
+    # ip -br a
+    lo               UNKNOWN        127.0.0.1/8 ::1/128
+    lo2              UNKNOWN        3fff::/128 fe80::dc87:34ff:fe4e:ccee/64
+    r2@if335         UP             2001:db8::/127 fe80::200:ff:fe00:0/64
+    # ip -br l
+    lo               UNKNOWN        00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
+    lo2              UNKNOWN        de:87:34:4e:cc:ee <BROADCAST,NOARP,UP,LOWER_UP>
+    r2@if335         UP             00:00:00:00:00:00 <BROADCAST,MULTICAST,NOARP,UP,LOWER_UP>
+    # ip -6 r
+    2001:db8::/127 dev r2 proto kernel metric 256 pref medium
+    3fff:: dev lo2 proto kernel metric 256 pref medium
+    3fff::1 dev r2 metric 1024 pref medium
+    fe80::/64 dev lo2 proto kernel metric 256 pref medium
+    fe80::/64 dev r2 proto kernel metric 256 pref medium
+    # ping -c1 3fff::1
+    PING 3fff::1(3fff::1) 56 data bytes
+    64 bytes from 3fff::1: icmp_seq=1 ttl=64 time=0.093 ms
+    --- 3fff::1 ping statistics ---
+    1 packets transmitted, 1 received, 0% packet loss, time 0ms
+    rtt min/avg/max/mdev = 0.093/0.093/0.093/0.000 ms
+
+To stop the lab use:
+
+    # linux-network-namespace-labs down lab.conf

diff --git a/examples/layer3/lab.conf b/examples/layer3/lab.conf
new file mode 100644 (file)
index 0000000..9a67eed
--- /dev/null
+++ b/examples/layer3/lab.conf
@@ -0,0 +1,13 @@
+# Start lab with: linux-network-namespace-labs up lab.conf
+
+# r1 <-> r2
+
+
+net loops 3fff::/20
+net addrs 2001:db8::/32
+
+node r1 loops
+node r2 loops
+
+# Create a layer-3 link which doesn't require ARP
+link r1 r2 addrs l3