// SPDX-License-Identifier: Apache-2.0
// Copyright Authors of Cilium

package api

import (
	"fmt"
)

// DropMin numbers less than this are non-drop reason codes
var DropMin uint8 = 130

// DropInvalid is the Invalid packet reason.
var DropInvalid uint8 = 2

// These values are shared with bpf/lib/common.h and api/v1/flow/flow.proto.
var errors = map[uint8]string{
	0:   "Success",
	2:   "Invalid packet",
	3:   "Interface",
	4:   "Interface Decrypted",
	5:   "LB, sock cgroup: No backend slot entry found",
	6:   "LB, sock cgroup: No backend entry found",
	7:   "LB, sock cgroup: Reverse entry update failed",
	8:   "LB, sock cgroup: Reverse entry stale",
	9:   "Fragmented packet",
	10:  "Fragmented packet entry update failed",
	11:  "Missed tail call to custom program",
	130: "Invalid source mac",      // Unused
	131: "Invalid destination mac", // Unused
	132: "Invalid source ip",
	133: "Policy denied",
	134: "Invalid packet",
	135: "CT: Truncated or invalid header",
	136: "Fragmentation needed",
	137: "CT: Unknown L4 protocol",
	138: "CT: Can't create entry from packet", // Unused
	139: "Unsupported L3 protocol",
	140: "Missed tail call",
	141: "Error writing to packet",
	142: "Unknown L4 protocol",
	143: "Unknown ICMPv4 code",
	144: "Unknown ICMPv4 type",
	145: "Unknown ICMPv6 code",
	146: "Unknown ICMPv6 type",
	147: "Error retrieving tunnel key",
	148: "Error retrieving tunnel options", // Unused
	149: "Invalid Geneve option",           // Unused
	150: "Unknown L3 target address",
	151: "Stale or unroutable IP",
	152: "No matching local container found", // Unused
	153: "Error while correcting L3 checksum",
	154: "Error while correcting L4 checksum",
	155: "CT: Map insertion failed",
	156: "Invalid IPv6 extension header",
	157: "IP fragmentation not supported",
	158: "Service backend not found",
	160: "No tunnel/encapsulation endpoint (datapath BUG!)",
	161: "NAT 46/64 not enabled",
	162: "Reached EDT rate-limiting drop horizon",
	163: "Unknown connection tracking state",
	164: "Local host is unreachable",
	165: "No configuration available to perform policy decision", // Unused
	166: "Unsupported L2 protocol",
	167: "No mapping for NAT masquerade",
	168: "Unsupported protocol for NAT masquerade",
	169: "FIB lookup failed",
	170: "Encapsulation traffic is prohibited",
	171: "Invalid identity",
	172: "Unknown sender",
	173: "NAT not needed",
	174: "Is a ClusterIP",
	175: "First logical datagram fragment not found",
	176: "Forbidden ICMPv6 message",
	177: "Denied by LB src range check",
	178: "Socket lookup failed",
	179: "Socket assign failed",
	180: "Proxy redirection not supported for protocol",
	181: "Policy denied by denylist",
	182: "VLAN traffic disallowed by VLAN filter",
	183: "Incorrect VNI from VTEP",
	184: "Failed to update or lookup TC buffer",
	185: "No SID was found for the IP address",
	186: "SRv6 state was removed during tail call",
	187: "L3 translation from IPv4 to IPv6 failed (NAT46)",
	188: "L3 translation from IPv6 to IPv4 failed (NAT64)",
	189: "Authentication required",
	190: "No conntrack map found",
	191: "No nat map found",
	192: "Invalid ClusterID",
	193: "Unsupported packet protocol for DSR encapsulation",
	194: "No egress gateway found",
}

func extendedReason(reason uint8, extError int8) string {
	if extError == int8(0) {
		return ""
	}
	return fmt.Sprintf("%d", extError)
}

func DropReasonExt(reason uint8, extError int8) string {
	if err, ok := errors[reason]; ok {
		if ext := extendedReason(reason, extError); ext == "" {
			return err
		} else {
			return err + ", " + ext
		}
	}
	return fmt.Sprintf("%d, %d", reason, extError)
}

// DropReason prints the drop reason in a human readable string
func DropReason(reason uint8) string {
	return DropReasonExt(reason, int8(0))
}
