Adds support for interface on BSD and MacOS

Signed-off-by: Clinton Wolfe <clintoncwolfe@gmail.com>

docs/resources/interface.md.erb

@@ -9,7 +9,7 @@ Use the `interface` Chef InSpec audit resource to test basic network adapter pro
 
 * On Linux platforms, `/sys/class/net/#{iface}` is used as source
 * On the Windows platform, the `Get-NetAdapter` cmdlet is used as source
-* The MacOS platform is not currently supported.
+* On BSD and MacOS platforms, the `ifconfig` command is used as source. Link speed may not be available.
 
 <br>
 
@@ -81,7 +81,7 @@ The `name` property returns the name of the interface:
 
 ### speed
 
-The `speed` property tests the speed of the network interface, in MB/sec:
+The `speed` property tests the speed of the network interface, in MB/sec. Note: On BSD and MacOS platforms, this value may be nil, because it difficult to obtain reliably.
 
     its('speed') { should eq 1000 }
 

lib/inspec/resources/interface.rb

@@ -85,6 +85,7 @@ module Inspec::Resources
       @cache ||= begin
                    provider = LinuxInterface.new(inspec) if inspec.os.linux?
                    provider = WindowsInterface.new(inspec) if inspec.os.windows?
+                   provider = BsdInterface.new(inspec) if inspec.os.bsd? # includes macOS
                    Hash(provider && provider.interface_info(@iface))
                  end
     end
@@ -98,6 +99,52 @@ module Inspec::Resources
     end
   end
 
+  class BsdInterface < InterfaceInfo
+    def interface_info(iface)
+      cmd = inspec.command("ifconfig #{iface}")
+      return nil if cmd.exit_status.to_i != 0
+
+      lines = cmd.stdout.split("\n")
+      iface_info = {
+        name: iface,
+        ipv4_addresses: [], # Actually CIDRs
+        ipv6_addresses: [], # are expected to go here
+      }
+
+      iface_info[:up] = lines[0].include?("UP")
+      lines.each do |line|
+        # IPv4 case
+        m = line.match(/^\s+inet\s+((?:\d{1,3}\.){3}\d{1,3})\s+netmask\s+(0x[a-f0-9]{8})/)
+        if m
+          ip = m[1]
+          hex_mask = m[2]
+          cidr = hex_mask.to_i(16).to_s(2).count("1")
+          iface_info[:ipv4_addresses] << "#{ip}/#{cidr}"
+          next
+        end
+
+        # IPv6 case
+        m = line.match(/^\s+inet6\s+([a-f0-9:]+)%#{iface}\s+prefixlen\s+(\d+)/)
+        if m
+          ip = m[1]
+          cidr = m[2]
+          iface_info[:ipv6_addresses] << "#{ip}/#{cidr}"
+          next
+        end
+
+        # Speed detect, crummy - can't detect wifi, finds any number in the string
+        # Ethernet autoselect (1000baseT <full-duplex>)
+        m = line.match(/^\s+media:\D+(\d+)/)
+        if m
+          iface_info[:speed] = m[1].to_i
+          next
+        end
+      end
+
+      iface_info
+    end
+  end
+
   class LinuxInterface < InterfaceInfo
     def interface_info(iface)
       # will return "[mtu]\n1500\n[type]\n1"

test/fixtures/cmd/ifconfig-en0

@@ -0,0 +1,7 @@
+en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
+	ether ac:bc:32:c7:30:e7
+	inet6 fe80::8b6:c2cc:2928:3b61%en0 prefixlen 64 secured scopeid 0x5
+	inet 192.168.1.2 netmask 0xffffff00 broadcast 192.168.1.255
+	nd6 options=201<PERFORMNUD,DAD>
+	media: Ethernet autoselect (1000baseT <full-duplex>)
+	status: active

test/helpers/mock_loader.rb

@@ -314,6 +314,7 @@ class MockLoader
       "/sbin/ip -br -6 address show dev eth0" => cmd.call("interface-addresses-6"),
       "Get-NetAdapter | Select-Object -Property Name, InterfaceDescription, Status, State, MacAddress, LinkSpeed, ReceiveLinkSpeed, TransmitLinkSpeed, Virtual | ConvertTo-Json" => cmd.call("Get-NetAdapter"),
       "Get-NetIPAddress | Select-Object -Property IPv6Address, IPv4Address, InterfaceAlias, PrefixLength | ConvertTo-Json" => cmd.call("Get-NetIPAddress"),
+      "ifconfig en0" => cmd.call("ifconfig-en0"),
       # bridge on linux
       "ls -1 /sys/class/net/br0/brif/" => cmd.call("ls-sys-class-net-br"),
       # bridge on Windows

test/unit/resources/interface_test.rb

@@ -81,6 +81,21 @@ describe "Inspec::Resources::Interface" do
     _(resource.ipv6_cidrs).must_be_empty
   end
 
+  it "verify interface on macos" do
+    resource = MockLoader.new(:osx104).load_resource("interface", "en0")
+    _(resource.exists?).must_equal true
+    _(resource.up?).must_equal true
+    _(resource.speed).must_equal 1000
+    _(resource.name).must_equal "en0"
+    _(resource.ipv4_cidrs).must_include "192.168.1.2/24"
+    _(resource.ipv4_addresses).must_include "192.168.1.2"
+    _(resource.ipv4_addresses_netmask).must_include "192.168.1.2/255.255.255.0"
+    _(resource.ipv6_cidrs).must_include "fe80::8b6:c2cc:2928:3b61/64"
+    _(resource.ipv6_addresses).must_include "fe80::8b6:c2cc:2928:3b61"
+    _(resource.ipv4_address?).must_equal true
+    _(resource.ipv6_address?).must_equal true
+  end
+
   # undefined
   it "verify interface on unsupported os" do
     resource = MockLoader.new(:undefined).load_resource("interface", "eth0")