[ztp] add Opt60 (vc) and Opt124 (vico) parsing

1 files changed, 139 insertions, 0 deletions

diff --git a/dhcpv4/ztp/ztp.go b/dhcpv4/ztp/ztp.go
new file mode 100644
index 0000000..7e1009f
--- /dev/null
+++ b/dhcpv4/ztp/ztp.go
@@ -0,0 +1,139 @@
+package ztpv4
+
+import (
+	"bytes"
+	"errors"
+	"strings"
+
+	"github.com/golang/glog"
+	"github.com/insomniacslk/dhcp/dhcpv4"
+)
+
+// VendorData is optional data a particular vendor may or may not include
+// in the Vendor Class options.  All values are optional and will be zero
+// values if not found.
+type VendorData struct {
+	VendorName string
+	Model      string
+	Serial     string
+}
+
+var errVendorOptionMalformed = errors.New("malformed vendor option")
+
+// VendorDataV4 will try to parse dhcp4 options data looking for more specific
+// vendor data (like model, serial number, etc).  If the options are missing
+func VendorDataV4(packet *dhcpv4.DHCPv4) VendorData {
+	vd := VendorData{}
+
+	if err := parseV4VendorClass(&vd, packet); err != nil {
+		glog.Errorf("failed to parse vendor data from vendor class: %v", err)
+	}
+
+	if err := parseV4VIVC(&vd, packet); err != nil {
+		glog.Errorf("failed to parse vendor data from vendor-idenitifying vendor class: %v", err)
+	}
+
+	return vd
+}
+
+// parseV4Opt60 will attempt to look at the Vendor Class option (Option 60) on
+// DHCPv4.  The option is formatted as a string with the content being specific
+// for the vendor, usually using a deliminator to separate the values.
+// See: https://tools.ietf.org/html/rfc1533#section-9.11
+func parseV4VendorClass(vd *VendorData, packet *dhcpv4.DHCPv4) error {
+	opt := packet.GetOneOption(dhcpv4.OptionClassIdentifier)
+	if opt == nil {
+		return nil
+	}
+	vc := opt.(*dhcpv4.OptClassIdentifier).Identifier
+
+	switch {
+	// Arista;DCS-7050S-64;01.23;JPE12221671
+	case strings.HasPrefix(vc, "Arista;"):
+		p := strings.Split(vc, ";")
+		if len(p) < 4 {
+			return errVendorOptionMalformed
+		}
+
+		vd.VendorName = p[0]
+		vd.Model = p[1]
+		vd.Serial = p[3]
+		return nil
+
+	// ZPESystems:NSC:002251623
+	case strings.HasPrefix(vc, "ZPESystems:"):
+		p := strings.Split(vc, ":")
+		if len(p) < 3 {
+			return errVendorOptionMalformed
+		}
+
+		vd.VendorName = p[0]
+		vd.Model = p[1]
+		vd.Serial = p[2]
+		return nil
+
+	// Juniper option 60 parsing is a bit more nuanced.  The following are all
+	// "valid" indetifing stings for Juniper:
+	//    Juniper-ptx1000-DD576      <vendor>-<model>-<serial
+	//    Juniper-qfx10008           <vendor>-<model> (serial in hostname option)
+	//    Juniper-qfx10002-361-DN817 <vendor>-<model>-<serial> (model has a dash in it!)
+	case strings.HasPrefix(vc, "Juniper-"):
+		// strip of the prefix
+		vc := vc[len("Juniper-"):]
+		vd.VendorName = "Juniper"
+
+		sepIdx := strings.LastIndex(vc, "-")
+		if sepIdx == -1 {
+			// No separator was found. Attempt serial number from the hostname
+			if opt := packet.GetOneOption(dhcpv4.OptionHostName); opt != nil {
+				vd.Serial = opt.(*dhcpv4.OptHostName).HostName
+			}
+		} else {
+			vd.Serial = vc[sepIdx+1:]
+			vc = vc[:sepIdx]
+		}
+		vd.Model = vc
+
+		return nil
+	}
+
+	// We didn't match anything, just return an empty vendor data.
+	return nil
+}
+
+const entIDCiscoSystems = 0x9
+
+// parseV4Opt124 will attempt to read the Vendor-Identifying Vendor Class
+// (Option 124) on a DHCPv4 packet.  The data is represented in a length/value
+// format with an indentifying enterprise number.
+//
+// See: https://tools.ietf.org/html/rfc3925
+func parseV4VIVC(vd *VendorData, packet *dhcpv4.DHCPv4) error {
+	opt := packet.GetOneOption(dhcpv4.OptionVendorIdentifyingVendorClass)
+	if opt == nil {
+		return nil
+	}
+	ids := opt.(*dhcpv4.OptVIVC).Identifiers
+
+	for _, id := range ids {
+		if id.EntID == entIDCiscoSystems {
+			vd.VendorName = "Cisco Systems"
+
+			//SN:0;PID:R-IOSXRV9000-CC
+			for _, f := range bytes.Split(id.Data, []byte(";")) {
+				p := bytes.SplitN(f, []byte(":"), 2)
+				if len(p) != 2 {
+					return errVendorOptionMalformed
+				}
+
+				switch string(p[0]) {
+				case "SN":
+					vd.Serial = string(p[1])
+				case "PID":
+					vd.Model = string(p[1])
+				}
+			}
+		}
+	}
+	return nil
+}