From 9a947b32a74e5f2866f12d9552e1265c3e3650a6 Mon Sep 17 00:00:00 2001
From: Nat Lasseter <user@4574.co.uk>
Date: Wed, 8 May 2024 14:23:26 +0100
Subject: Demo ends. For now...

---
 03-switch3.rb | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 03-switch3.rb

(limited to '03-switch3.rb')

diff --git a/03-switch3.rb b/03-switch3.rb
new file mode 100644
index 0000000..7cbdc2f
--- /dev/null
+++ b/03-switch3.rb
@@ -0,0 +1,61 @@
+require './level'
+require './frame2'
+
+$levels << Level.new do
+  @interfaces = %w(1 2 3)
+  @description = <<~EOD
+    You are now a three-port switch.
+    When a frame comes in on a port, you should keep track of the source address,
+      and any frames destined for that address in future clicks should only be
+      forwarded to that port. All other frames should be broadcast as before.
+  EOD
+  @clicks = 8
+
+  @fib = @interfaces.product([nil]).to_h
+  @next_fib = @fib.dup
+
+  def target(frame)
+    ifib = @fib.invert
+    if ifib.keys.include?(frame.dst_addr)
+      [frame.to(ifib[frame.dst_addr])]
+    else
+      case frame.iface
+      when ?1
+        [frame.to(?2), frame.to(?3)]
+      when ?2
+        [frame.to(?1), frame.to(?3)]
+      when ?3
+        [frame.to(?1), frame.to(?2)]
+      else
+        []
+      end
+    end
+  end
+
+  def generate
+    frames = {}
+    @interfaces.each do |iface|
+      next if rand < 0.3
+
+      if rand < 0.4 || @fib[iface].nil?
+        src = Frame2.gen_addr
+        @next_fib[iface] = src
+      else
+        src = @fib[iface]
+      end
+
+      dst = nil
+      dst = (@fib.values.compact - [src]).sample if rand < 0.5
+      dst = Frame2.gen_addr if dst.nil?
+
+      frames[@count.to_s] = Frame2.new(iface, src, dst)
+      @count += 1
+    end
+    frames
+  end
+
+  def click
+    @fib = @next_fib
+    @next_fib = @fib.dup
+  end
+end
-- 
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