[dhcpv6/ztpv6] Adding Parsing Vendor Opts and Parsing Remote Id Opts lib for ztpv6 (#208)

1 files changed, 84 insertions, 0 deletions

diff --git a/dhcpv6/ztpv6/parse_remote_id.go b/dhcpv6/ztpv6/parse_remote_id.go
new file mode 100644
index 0000000..5991e96
--- /dev/null
+++ b/dhcpv6/ztpv6/parse_remote_id.go
@@ -0,0 +1,84 @@
+package ztpv6
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+
+	"github.com/insomniacslk/dhcp/dhcpv6"
+)
+
+var (
+	// Arista Port, Vlan Pattern
+	aristaPVPattern = regexp.MustCompile("Ethernet(?P<port>[0-9]+):(?P<vlan>[0-9]+)")
+	// Arista Slot, Mod, Port Pattern
+	aristaSMPPattern = regexp.MustCompile("Ethernet(?P<slot>[0-9]+)/(?P<module>[0-9]+)/(?P<port>[0-9]+)")
+)
+
+// CircuitID represents the structure of network vendor interface formats
+type CircuitID struct {
+	Slot    string
+	Module  string
+	Port    string
+	SubPort string
+	Vlan    string
+}
+
+// ParseRemoteId will parse the RemoteId Option data for Vendor Specific data
+func ParseRemoteId(packet dhcpv6.DHCPv6) (*CircuitID, error) {
+	// Need to decapsulate the packet after multiple relays in order to reach RemoteId data
+	inner, err := dhcpv6.DecapsulateRelayIndex(packet, -1)
+	if err != nil {
+		return nil, fmt.Errorf("failed to decapsulate relay index: %v", err)
+	}
+
+	if rid := inner.GetOneOption(dhcpv6.OptionRemoteID); rid != nil {
+		remoteID := string(rid.(*dhcpv6.OptRemoteId).RemoteID())
+		circ, err := matchCircuitId(remoteID)
+		if err != nil {
+			return nil, err
+		}
+		return circ, nil
+	}
+	return nil, errors.New("failed to parse RemoteID option data")
+}
+
+func matchCircuitId(remoteID string) (*CircuitID, error) {
+	var names, matches []string
+
+	switch {
+	case aristaPVPattern.MatchString(remoteID):
+		matches = aristaPVPattern.FindStringSubmatch(remoteID)
+		names = aristaPVPattern.SubexpNames()
+	case aristaSMPPattern.MatchString(remoteID):
+		matches = aristaSMPPattern.FindStringSubmatch(remoteID)
+		names = aristaSMPPattern.SubexpNames()
+	}
+
+	if len(matches) == 0 {
+		return nil, fmt.Errorf("no circuitId regex matches for %v", remoteID)
+	}
+
+	var circuit CircuitID
+	for i, match := range matches {
+		switch names[i] {
+		case "port":
+			circuit.Port = match
+		case "slot":
+			circuit.Slot = match
+		case "module":
+			circuit.Module = match
+		case "subport":
+			circuit.SubPort = match
+		case "vlan":
+			circuit.Vlan = match
+		}
+	}
+
+	return &circuit, nil
+}
+
+// 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)
+}