1 files changed, 94 insertions, 0 deletions
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)
+}