simulator.go

/*
Copyright (c) 2014 VMware, Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package ipmi

import (
	"bytes"

	"hash/adler32"
	"log"
	"net"
	"sync"
)

const authTypeSupport = (1 << AuthTypeNone) | (1 << AuthTypeMD5) | (1 << AuthTypePassword)

// Handler function
type Handler func(*Message) Response

// Simulator for IPMI
type Simulator struct {
	wg       sync.WaitGroup
	addr     net.UDPAddr
	conn     *net.UDPConn
	handlers map[NetworkFunction]map[Command]Handler
	ids      map[uint32]string
	bopts    [BootParamInitMbox + 1][]uint8
}

// NewSimulator constructs a Simulator with the given addr
func NewSimulator(addr net.UDPAddr) *Simulator {
	s := &Simulator{
		addr:     addr,
		ids:      map[uint32]string{},
		handlers: map[NetworkFunction]map[Command]Handler{},
	}

	// Built-in handlers for session management
	s.handlers[NetworkFunctionApp] = map[Command]Handler{
		CommandGetDeviceID:              s.deviceID,
		CommandGetAuthCapabilities:      s.authCapabilities,
		CommandGetSessionChallenge:      s.sessionChallenge,
		CommandActivateSession:          s.sessionActivate,
		CommandSetSessionPrivilegeLevel: s.sessionPrivilege,
		CommandCloseSession:             s.sessionClose,
		CommandGetUserName:              s.getUserName,
		CommandSetUserName:              s.setUserName,
	}

	// Built-in handlers for chassis commands
	s.handlers[NetworkFunctionChassis] = map[Command]Handler{
		CommandChassisStatus:        s.chassisStatus,
		CommandGetSystemBootOptions: s.getSystemBootOptions,
		CommandSetSystemBootOptions: s.setSystemBootOptions,
	}

	return s
}

// SetHandler sets the command handler for the given netfn and command
func (s *Simulator) SetHandler(netfn NetworkFunction, command Command, handler Handler) {
	s.handlers[netfn][command] = handler
}

// NewConnection to this Simulator instance
func (s *Simulator) NewConnection() *Connection {
	addr := s.LocalAddr()
	return &Connection{
		Hostname:  addr.IP.String(),
		Port:      addr.Port,
		Interface: "lan",
	}
}

// LocalAddr returns the address the server is bound to.
func (s *Simulator) LocalAddr() *net.UDPAddr {
	if s.conn != nil {
		return s.conn.LocalAddr().(*net.UDPAddr)
	}
	return nil
}

// Run the Simulator.
func (s *Simulator) Run() error {
	var err error
	s.conn, err = net.ListenUDP("udp4", &s.addr)
	if err != nil {
		return err
	}

	s.wg.Add(1)

	go func() {
		_ = s.serve()
		s.wg.Done()
	}()

	return nil
}

// Stop the Simulator.
func (s *Simulator) Stop() {
	_ = s.conn.Close()
	s.wg.Wait()
}

func (s *Simulator) chassisStatus(*Message) Response {
	return &ChassisStatusResponse{
		CompletionCode: CommandCompleted,
		PowerState:     SystemPower,
	}
}

func (s *Simulator) getSystemBootOptions(m *Message) Response {
	r := &SystemBootOptionsRequest{}
	if err := m.Request(r); err != nil {
		return err
	}

	return &SystemBootOptionsResponse{
		CompletionCode: CommandCompleted,
		Version:        0x01,
		Param:          r.Param,
		Data:           s.bopts[r.Param],
	}
}

func (s *Simulator) setSystemBootOptions(m *Message) Response {
	r := &SetSystemBootOptionsRequest{}
	if err := m.Request(r); err != nil {
		return err
	}

	s.bopts[r.Param] = r.Data

	return &SetSystemBootOptionsResponse{}
}

func (s *Simulator) deviceID(*Message) Response {
	return &DeviceIDResponse{
		CompletionCode: CommandCompleted,
		IPMIVersion:    0x51, // 1.5
	}
}

var users = []string{"admin", "", "", "", ""}

func (s *Simulator) getUserName(m *Message) Response {
	req := &GetUserNameRequest{}
	if err := m.Request(req); err != nil {
		return err
	}
	return &GetUserNameResponse{
		CompletionCode: CommandCompleted,
		Username:       users[req.UserID],
	}
}

func (s *Simulator) setUserName(m *Message) Response {
	req := &SetUserNameRequest{}
	if err := m.Request(req); err != nil {
		return err
	}
	users[req.UserID] = req.Username
	return &SetUserNameResponse{
		CompletionCode: CommandCompleted,
	}
}

func (s *Simulator) authCapabilities(*Message) Response {
	return &AuthCapabilitiesResponse{
		CompletionCode:  CommandCompleted,
		ChannelNumber:   0x01,
		AuthTypeSupport: authTypeSupport,
	}
}

func (s *Simulator) sessionChallenge(m *Message) Response {
	// Convert username to a uint32 and use as the SessionID.
	// The SessionID will be propagated such that all requests
	// for this session include the ID, which can be used to
	// dispatch requests.
	username := bytes.TrimRight(m.Data[1:], "\000")
	hash := adler32.New()
	_, err := hash.Write(username)
	if err != nil {
		panic(err)
	}
	id := hash.Sum32()

	s.ids[id] = string(username)

	return &SessionChallengeResponse{
		CompletionCode:     CommandCompleted,
		TemporarySessionID: id,
	}
}

func (s *Simulator) sessionActivate(m *Message) Response {
	return &ActivateSessionResponse{
		CompletionCode: CommandCompleted,
		AuthType:       m.AuthType,
		SessionID:      m.SessionID,
		InboundSeq:     m.Sequence,
		MaxPriv:        PrivLevelAdmin,
	}
}

func (s *Simulator) sessionPrivilege(m *Message) Response {
	return &SessionPrivilegeLevelResponse{
		CompletionCode:    CommandCompleted,
		NewPrivilegeLevel: m.Data[0],
	}
}

func (s *Simulator) sessionClose(*Message) Response {
	return CommandCompleted
}

func (s *Simulator) ipmiCommand(m *Message) []byte {
	response := Response(ErrInvalidCommand)

	if commands, ok := s.handlers[m.NetFn()]; ok {
		if handler, ok := commands[m.Command]; ok {
			m.RequestID = s.ids[m.SessionID]
			response = handler(m)
		}
	}

	return m.toBytes(response)
}

func (s *Simulator) asfCommand(m *asfMessage) []byte {
	if m.MessageType != asfMessageTypePing {
		log.Print(m.unsupportedMessageType())
		return []byte{} // TODO: general ASF error code?
	}

	m.MessageType = asfMessageTypePong
	response := asfPong{
		IANAEnterpriseNumber: asfIANA,
		SupportedEntities:    0x81, // IPMI
	}

	return m.toBytes(&response)
}

func (s *Simulator) serve() error {
	buf := make([]byte, ipmiBufSize)

	for {
		var response []byte
		var err error

		n, addr, err := s.conn.ReadFrom(buf)
		if err != nil {
			return err // conn closed
		}

		header, err := rmcpHeaderFromBytes(buf)
		if err != nil {
			log.Print(err)
			continue
		}

		switch header.Class {
		case rmcpClassASF:
			m, err := asfMessageFromBytes(buf)
			if err != nil {
				log.Print(err)
				continue
			}

			response = s.asfCommand(m)
		case rmcpClassIPMI:
			m, err := messageFromBytes(buf[:n])
			if err != nil {
				log.Print(err)
				continue
			}

			response = s.ipmiCommand(m)
		default:
			log.Print(header.unsupportedClass())
			continue
		}

		_, err = s.conn.WriteTo(response, addr)
		if err != nil {
			return err // conn closed
		}
	}
}