Adding CircuitId parsing logic into dhcpv4 lib (#255)

3 files changed, 223 insertions, 0 deletions

diff --git a/dhcpv4/option_relay_agent_information.go b/dhcpv4/option_relay_agent_information.go
index 8b88b0c..56d93f2 100644
--- a/dhcpv4/option_relay_agent_information.go
+++ b/dhcpv4/option_relay_agent_information.go
@@ -36,3 +36,23 @@ func (r *RelayOptions) FromBytes(data []byte) error {
 func OptRelayAgentInfo(o ...Option) Option {
 	return Option{Code: OptionRelayAgentInformation, Value: RelayOptions{OptionsFromList(o...)}}
 }
+
+type raiSubOptionCode uint8
+
+func (o raiSubOptionCode) Code() uint8 {
+	return uint8(o)
+}
+
+func (o raiSubOptionCode) String() string {
+	if s, ok := raiSubOptionCodeToString[o]; ok {
+		return s
+	}
+	return fmt.Sprintf("unknown (%d)", o)
+}
+
+// AgentCircuitIDSubOption as per https://tools.ietf.org/html/rfc3046#section-2.0
+const AgentCircuitIDSubOption raiSubOptionCode = 1
+
+var raiSubOptionCodeToString = map[raiSubOptionCode]string{
+	AgentCircuitIDSubOption: "Agent Circuit ID Sub-option",
+}
diff --git a/dhcpv4/ztpv4/parse_circuitid.go b/dhcpv4/ztpv4/parse_circuitid.go
new file mode 100644
index 0000000..b9db358
--- /dev/null
+++ b/dhcpv4/ztpv4/parse_circuitid.go
@@ -0,0 +1,94 @@
+package ztpv4
+
+import (
+	"fmt"
+	"regexp"
+
+	"github.com/insomniacslk/dhcp/dhcpv4"
+)
+
+// CircuitID represents the structure of network vendor interface formats
+type CircuitID struct {
+	Slot    string
+	Module  string
+	Port    string
+	SubPort string
+	Vlan    string
+}
+
+var circuitRegexs = []*regexp.Regexp{
+	// Juniper QFX et-0/0/0:0.0
+	regexp.MustCompile("^et-(?P<slot>[0-9]+)/(?P<mod>[0-9]+)/(?P<port>[0-9]+):(?P<subport>[0-9]+).*$"),
+	// Juniper PTX et-0/0/0.0
+	regexp.MustCompile("^et-(?P<slot>[0-9]+)/(?P<mod>[0-9]+)/(?P<port>[0-9]+).(?P<subport>[0-9]+)$"),
+	// Arista Ethernet3/17/1
+	regexp.MustCompile("^Ethernet(?P<slot>[0-9]+)/(?P<mod>[0-9]+)/(?P<port>[0-9]+)$"),
+	// Juniper QFX et-1/0/61
+	regexp.MustCompile("^et-(?P<slot>[0-9]+)/(?P<mod>[0-9]+)/(?P<port>[0-9]+)$"),
+	// Arista Ethernet14:Vlan2001
+	// Arista Ethernet10:2020
+	regexp.MustCompile("^Ethernet(?P<port>[0-9]+):(?P<vlan>.*)$"),
+	// Cisco Gi1/10:2020
+	regexp.MustCompile("^Gi(?P<slot>[0-9]+)/(?P<port>[0-9]+):(?P<vlan>.*)$"),
+	// Nexus Ethernet1/3
+	regexp.MustCompile("^Ethernet(?P<slot>[0-9]+)/(?P<port>[0-9]+)$"),
+	// Juniper bundle interface ae52.0
+	regexp.MustCompile("^ae(?P<port>[0-9]+).(?P<subport>[0-9])$"),
+}
+
+// ParseCircuitID will parse dhcpv4 packet and return CircuitID info
+func ParseCircuitID(packet *dhcpv4.DHCPv4) (*CircuitID, error) {
+	// CircuitId info is stored as sub-option field in RelayAgentInformationOption
+	relayOptions := packet.RelayAgentInfo()
+
+	if relayOptions == nil {
+		return nil, fmt.Errorf("No relay agent information option found in the dhcpv4 pkt")
+	}
+
+	// As per RFC 3046 sub-Option 1 is circuit-id. Look at 2.0 section in that RFC
+	// https://tools.ietf.org/html/rfc3046
+	circuitIdStr := string(relayOptions.Options.Get(dhcpv4.AgentCircuitIDSubOption))
+	if circuitIdStr == "" {
+		return nil, fmt.Errorf("no circuit-id suboption found in dhcpv4 packet")
+	}
+	circuitId, err := matchCircuitID(circuitIdStr)
+	if err != nil {
+		return nil, err
+	}
+	return circuitId, nil
+}
+
+func matchCircuitID(circuitIdStr string) (*CircuitID, error) {
+
+	for _, re := range circuitRegexs {
+
+		match := re.FindStringSubmatch(circuitIdStr)
+		if len(match) == 0 {
+			continue
+		}
+
+		c := CircuitID{}
+		for i, k := range re.SubexpNames() {
+			switch k {
+			case "slot":
+				c.Slot = match[i]
+			case "mod":
+				c.Module = match[i]
+			case "port":
+				c.Port = match[i]
+			case "subport":
+				c.SubPort = match[i]
+			case "vlan":
+				c.Vlan = match[i]
+			}
+		}
+
+		return &c, nil
+	}
+	return nil, fmt.Errorf("Unable to match circuit id : %s with listed regexes of interface types", circuitIdStr)
+}
+
+// FormatCircuitID is the CircuitID format we send in our Bootfile URL for ZTP devices
+func (c *CircuitID) FormatCircuitID() string {
+	return fmt.Sprintf("%v,%v,%v,%v,%v", c.Slot, c.Module, c.Port, c.SubPort, c.Vlan)
+}
diff --git a/dhcpv4/ztpv4/parse_circuitid_test.go b/dhcpv4/ztpv4/parse_circuitid_test.go
new file mode 100644
index 0000000..b075a16
--- /dev/null
+++ b/dhcpv4/ztpv4/parse_circuitid_test.go
@@ -0,0 +1,109 @@
+package ztpv4
+
+import (
+	"testing"
+
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMatchCircuitID(t *testing.T) {
+	tt := []struct {
+		name    string
+		circuit string
+		want    *CircuitID
+		fail    bool
+	}{
+		{name: "Bogus string", circuit: "bogus_interface", fail: true, want: nil},
+		{name: "juniperQFX pattern", circuit: "et-0/0/0:0.0", want: &CircuitID{Slot: "0", Module: "0", Port: "0", SubPort: "0"}},
+		{name: "juniperPTX pattern", circuit: "et-0/0/0.0", want: &CircuitID{Slot: "0", Module: "0", Port: "0", SubPort: "0"}},
+		{name: "Arista pattern", circuit: "Ethernet3/17/1", want: &CircuitID{Slot: "3", Module: "17", Port: "1"}},
+		{name: "Juniper QFX pattern", circuit: "et-1/0/61", want: &CircuitID{Slot: "1", Module: "0", Port: "61"}},
+		{name: "Arista Vlan pattern 1", circuit: "Ethernet14:Vlan2001", want: &CircuitID{Port: "14", Vlan: "Vlan2001"}},
+		{name: "Arista Vlan pattern 2", circuit: "Ethernet10:2020", want: &CircuitID{Port: "10", Vlan: "2020"}},
+		{name: "Cisco pattern", circuit: "Gi1/10:2020", want: &CircuitID{Slot: "1", Port: "10", Vlan: "2020"}},
+		{name: "Cisco Nexus pattern", circuit: "Ethernet1/3", want: &CircuitID{Slot: "1", Port: "3"}},
+		{name: "Juniper Bundle Pattern", circuit: "ae52.0", want: &CircuitID{Port: "52", SubPort: "0"}},
+	}
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			circuit, err := matchCircuitID(tc.circuit)
+			if err != nil && !tc.fail {
+				t.Errorf("unexpected failure: %v", err)
+			}
+			if circuit != nil {
+				require.Equal(t, tc.want, circuit, "comparing CircuitID")
+			} else {
+				require.Equal(t, tc.want, circuit, "comparing CircuitID")
+			}
+		})
+	}
+}
+
+func TestFormatCircuitID(t *testing.T) {
+	tt := []struct {
+		name    string
+		circuit *CircuitID
+		want    string
+		fail    bool
+	}{
+		{name: "empty", circuit: &CircuitID{}, want: ",,,,"},
+		{name: "juniperQFX pattern", circuit: &CircuitID{Slot: "0", Module: "0", Port: "0", SubPort: "0"}, want: "0,0,0,0,"},
+		{name: "juniperPTX pattern", circuit: &CircuitID{Slot: "0", Module: "0", Port: "0"}, want: "0,0,0,,"},
+		{name: "Arista pattern", circuit: &CircuitID{Slot: "3", Module: "17", Port: "1"}, want: "3,17,1,,"},
+		{name: "Juniper QFX pattern", circuit: &CircuitID{Slot: "1", Module: "0", Port: "61"}, want: "1,0,61,,"},
+		{name: "Arista Vlan pattern 1", circuit: &CircuitID{Port: "14", Vlan: "Vlan2001"}, want: ",,14,,Vlan2001"},
+		{name: "Arista Vlan pattern 2", circuit: &CircuitID{Port: "10", Vlan: "2020"}, want: ",,10,,2020"},
+		{name: "Cisco Nexus pattern", circuit: &CircuitID{Slot: "1", Port: "3"}, want: "1,,3,,"},
+		{name: "Juniper Bundle Pattern", circuit: &CircuitID{Port: "52", SubPort: "0"}, want: ",,52,0,"},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			circuit := tc.circuit.FormatCircuitID()
+			require.Equal(t, tc.want, circuit, "FormatCircuitID data")
+		})
+	}
+
+}
+
+func TestParseCircuitID(t *testing.T) {
+	tt := []struct {
+		name    string
+		circuit []byte
+		want    *CircuitID
+		fail    bool
+	}{
+		{name: "Bogus test", circuit: []byte("bogusInterface"), fail: true, want: nil},
+		{name: "juniperQFX pattern", circuit: []byte("et-0/0/0:0.0"), want: &CircuitID{Slot: "0", Module: "0", Port: "0", SubPort: "0"}},
+		{name: "Bogus string", circuit: []byte("bogus_interface"), fail: true, want: nil},
+		{name: "juniperQFX pattern", circuit: []byte("et-0/0/0:0.0"), want: &CircuitID{Slot: "0", Module: "0", Port: "0", SubPort: "0"}},
+		{name: "juniperPTX pattern", circuit: []byte("et-0/0/0.0"), want: &CircuitID{Slot: "0", Module: "0", Port: "0", SubPort: "0"}},
+		{name: "Arista pattern", circuit: []byte("Ethernet3/17/1"), want: &CircuitID{Slot: "3", Module: "17", Port: "1"}},
+		{name: "Juniper QFX pattern", circuit: []byte("et-1/0/61"), want: &CircuitID{Slot: "1", Module: "0", Port: "61"}},
+		{name: "Arista Vlan pattern 1", circuit: []byte("Ethernet14:Vlan2001"), want: &CircuitID{Port: "14", Vlan: "Vlan2001"}},
+		{name: "Arista Vlan pattern 2", circuit: []byte("Ethernet10:2020"), want: &CircuitID{Port: "10", Vlan: "2020"}},
+		{name: "Cisco pattern", circuit: []byte("Gi1/10:2020"), want: &CircuitID{Slot: "1", Port: "10", Vlan: "2020"}},
+		{name: "Cisco Nexus pattern", circuit: []byte("Ethernet1/3"), want: &CircuitID{Slot: "1", Port: "3"}},
+		{name: "Juniper Bundle Pattern", circuit: []byte("ae52.0"), want: &CircuitID{Port: "52", SubPort: "0"}},
+	}
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+
+			addOption := dhcpv4.WithOption(dhcpv4.OptRelayAgentInfo(dhcpv4.OptGeneric(dhcpv4.GenericOptionCode(1), tc.circuit)))
+			packet, err := dhcpv4.New(addOption)
+			if err != nil {
+				t.Errorf("Unable to create dhcpv4 packet with circuiti")
+			}
+			c, err := ParseCircuitID(packet)
+			if err != nil && !tc.fail {
+				t.Errorf("Testcase Failed %v", err)
+			}
+			if c != nil {
+				require.Equal(t, *tc.want, *c, "Comparing DHCPv4 Relay Agent Info CircuitId")
+			} else {
+				require.Equal(t, tc.want, c, "Comparing DHCPv4 Relay Agent Info CircuitId")
+			}
+		})
+	}
+}