forked from hashicorp/consul
/
config.go
402 lines (336 loc) · 11.8 KB
/
config.go
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package consul
import (
"crypto/tls"
"crypto/x509"
"fmt"
"io"
"io/ioutil"
"net"
"os"
"time"
"github.com/hashicorp/memberlist"
"github.com/hashicorp/raft"
"github.com/hashicorp/serf/serf"
)
const (
DefaultDC = "dc1"
DefaultLANSerfPort = 8301
DefaultWANSerfPort = 8302
)
var (
DefaultRPCAddr = &net.TCPAddr{IP: net.ParseIP("0.0.0.0"), Port: 8300}
)
// ProtocolVersionMap is the mapping of Consul protocol versions
// to Serf protocol versions. We mask the Serf protocols using
// our own protocol version.
var protocolVersionMap map[uint8]uint8
func init() {
protocolVersionMap = map[uint8]uint8{
1: 4,
2: 4,
}
}
// Config is used to configure the server
type Config struct {
// Bootstrap mode is used to bring up the first Consul server.
// It is required so that it can elect a leader without any
// other nodes being present
Bootstrap bool
// BootstrapExpect mode is used to automatically bring up a collection of
// Consul servers. This can be used to automatically bring up a collection
// of nodes.
BootstrapExpect int
// Datacenter is the datacenter this Consul server represents
Datacenter string
// DataDir is the directory to store our state in
DataDir string
// Node name is the name we use to advertise. Defaults to hostname.
NodeName string
// RaftConfig is the configuration used for Raft in the local DC
RaftConfig *raft.Config
// RPCAddr is the RPC address used by Consul. This should be reachable
// by the WAN and LAN
RPCAddr *net.TCPAddr
// RPCAdvertise is the address that is advertised to other nodes for
// the RPC endpoint. This can differ from the RPC address, if for example
// the RPCAddr is unspecified "0.0.0.0:8300", but this address must be
// reachable
RPCAdvertise *net.TCPAddr
// SerfLANConfig is the configuration for the intra-dc serf
SerfLANConfig *serf.Config
// SerfWANConfig is the configuration for the cross-dc serf
SerfWANConfig *serf.Config
// ReconcileInterval controls how often we reconcile the strongly
// consistent store with the Serf info. This is used to handle nodes
// that are force removed, as well as intermittent unavailability during
// leader election.
ReconcileInterval time.Duration
// LogOutput is the location to write logs to. If this is not set,
// logs will go to stderr.
LogOutput io.Writer
// ProtocolVersion is the protocol version to speak. This must be between
// ProtocolVersionMin and ProtocolVersionMax.
ProtocolVersion uint8
// VerifyIncoming is used to verify the authenticity of incoming connections.
// This means that TCP requests are forbidden, only allowing for TLS. TLS connections
// must match a provided certificate authority. This can be used to force client auth.
VerifyIncoming bool
// VerifyOutgoing is used to verify the authenticity of outgoing connections.
// This means that TLS requests are used, and TCP requests are not made. TLS connections
// must match a provided certificate authority. This is used to verify authenticity of
// server nodes.
VerifyOutgoing bool
// CAFile is a path to a certificate authority file. This is used with VerifyIncoming
// or VerifyOutgoing to verify the TLS connection.
CAFile string
// CertFile is used to provide a TLS certificate that is used for serving TLS connections.
// Must be provided to serve TLS connections.
CertFile string
// KeyFile is used to provide a TLS key that is used for serving TLS connections.
// Must be provided to serve TLS connections.
KeyFile string
// ServerName is used with the TLS certificate to ensure the name we
// provide matches the certificate
ServerName string
// RejoinAfterLeave controls our interaction with Serf.
// When set to false (default), a leave causes a Consul to not rejoin
// the cluster until an explicit join is received. If this is set to
// true, we ignore the leave, and rejoin the cluster on start.
RejoinAfterLeave bool
// Build is a string that is gossiped around, and can be used to help
// operators track which versions are actively deployed
Build string
// ACLToken is the default token to use when making a request.
// If not provided, the anonymous token is used. This enables
// backwards compatibility as well.
ACLToken string
// ACLMasterToken is used to bootstrap the ACL system. It should be specified
// on the servers in the ACLDatacenter. When the leader comes online, it ensures
// that the Master token is available. This provides the initial token.
ACLMasterToken string
// ACLDatacenter provides the authoritative datacenter for ACL
// tokens. If not provided, ACL verification is disabled.
ACLDatacenter string
// ACLTTL controls the time-to-live of cached ACL policies.
// It can be set to zero to disable caching, but this adds
// a substantial cost.
ACLTTL time.Duration
// ACLDefaultPolicy is used to control the ACL interaction when
// there is no defined policy. This can be "allow" which means
// ACLs are used to black-list, or "deny" which means ACLs are
// white-lists.
ACLDefaultPolicy string
// ACLDownPolicy controls the behavior of ACLs if the ACLDatacenter
// cannot be contacted. It can be either "deny" to deny all requests,
// or "extend-cache" which ignores the ACLCacheInterval and uses
// cached policies. If a policy is not in the cache, it acts like deny.
// "allow" can be used to allow all requests. This is not recommended.
ACLDownPolicy string
// ServerUp callback can be used to trigger a notification that
// a Consul server is now up and known about.
ServerUp func()
// UserEventHandler callback can be used to handle incoming
// user events. This function should not block.
UserEventHandler func(serf.UserEvent)
}
// CheckVersion is used to check if the ProtocolVersion is valid
func (c *Config) CheckVersion() error {
if c.ProtocolVersion < ProtocolVersionMin {
return fmt.Errorf("Protocol version '%d' too low. Must be in range: [%d, %d]",
c.ProtocolVersion, ProtocolVersionMin, ProtocolVersionMax)
} else if c.ProtocolVersion > ProtocolVersionMax {
return fmt.Errorf("Protocol version '%d' too high. Must be in range: [%d, %d]",
c.ProtocolVersion, ProtocolVersionMin, ProtocolVersionMax)
}
return nil
}
// CheckACL is used to sanity check the ACL configuration
func (c *Config) CheckACL() error {
switch c.ACLDefaultPolicy {
case "allow":
case "deny":
default:
return fmt.Errorf("Unsupported default ACL policy: %s", c.ACLDefaultPolicy)
}
switch c.ACLDownPolicy {
case "allow":
case "deny":
case "extend-cache":
default:
return fmt.Errorf("Unsupported down ACL policy: %s", c.ACLDownPolicy)
}
return nil
}
// AppendCA opens and parses the CA file and adds the certificates to
// the provided CertPool.
func (c *Config) AppendCA(pool *x509.CertPool) error {
if c.CAFile == "" {
return nil
}
// Read the file
data, err := ioutil.ReadFile(c.CAFile)
if err != nil {
return fmt.Errorf("Failed to read CA file: %v", err)
}
if !pool.AppendCertsFromPEM(data) {
return fmt.Errorf("Failed to parse any CA certificates")
}
return nil
}
// KeyPair is used to open and parse a certificate and key file
func (c *Config) KeyPair() (*tls.Certificate, error) {
if c.CertFile == "" || c.KeyFile == "" {
return nil, nil
}
cert, err := tls.LoadX509KeyPair(c.CertFile, c.KeyFile)
if err != nil {
return nil, fmt.Errorf("Failed to load cert/key pair: %v", err)
}
return &cert, err
}
// OutgoingTLSConfig generates a TLS configuration for outgoing
// requests. It will return a nil config if this configuration should
// not use TLS for outgoing connections.
func (c *Config) OutgoingTLSConfig() (*tls.Config, error) {
if !c.VerifyOutgoing {
return nil, nil
}
// Create the tlsConfig
tlsConfig := &tls.Config{
RootCAs: x509.NewCertPool(),
InsecureSkipVerify: true,
}
if c.ServerName != "" {
tlsConfig.ServerName = c.ServerName
tlsConfig.InsecureSkipVerify = false
}
// Ensure we have a CA if VerifyOutgoing is set
if c.VerifyOutgoing && c.CAFile == "" {
return nil, fmt.Errorf("VerifyOutgoing set, and no CA certificate provided!")
}
// Parse the CA cert if any
err := c.AppendCA(tlsConfig.RootCAs)
if err != nil {
return nil, err
}
// Add cert/key
cert, err := c.KeyPair()
if err != nil {
return nil, err
} else if cert != nil {
tlsConfig.Certificates = []tls.Certificate{*cert}
}
return tlsConfig, nil
}
// Wrap a net.Conn into a client tls connection, performing any
// additional verification as needed.
//
// As of go 1.3, crypto/tls only supports either doing no certificate
// verification, or doing full verification including of the peer's
// DNS name. For consul, we want to validate that the certificate is
// signed by a known CA, but because consul doesn't use DNS names for
// node names, we don't verify the certificate DNS names. Since go 1.3
// no longer supports this mode of operation, we have to do it
// manually.
func wrapTLSClient(conn net.Conn, tlsConfig *tls.Config) (net.Conn, error) {
var err error
var tlsConn *tls.Conn
tlsConn = tls.Client(conn, tlsConfig)
// If crypto/tls is doing verification, there's no need to do
// our own.
if tlsConfig.InsecureSkipVerify == false {
return tlsConn, nil
}
if err = tlsConn.Handshake(); err != nil {
tlsConn.Close()
return nil, err
}
// The following is lightly-modified from the doFullHandshake
// method in crypto/tls's handshake_client.go.
opts := x509.VerifyOptions{
Roots: tlsConfig.RootCAs,
CurrentTime: time.Now(),
DNSName: "",
Intermediates: x509.NewCertPool(),
}
certs := tlsConn.ConnectionState().PeerCertificates
for i, cert := range certs {
if i == 0 {
continue
}
opts.Intermediates.AddCert(cert)
}
_, err = certs[0].Verify(opts)
if err != nil {
tlsConn.Close()
return nil, err
}
return tlsConn, err
}
// IncomingTLSConfig generates a TLS configuration for incoming requests
func (c *Config) IncomingTLSConfig() (*tls.Config, error) {
// Create the tlsConfig
tlsConfig := &tls.Config{
ServerName: c.ServerName,
ClientCAs: x509.NewCertPool(),
ClientAuth: tls.NoClientCert,
}
if tlsConfig.ServerName == "" {
tlsConfig.ServerName = c.NodeName
}
// Parse the CA cert if any
err := c.AppendCA(tlsConfig.ClientCAs)
if err != nil {
return nil, err
}
// Add cert/key
cert, err := c.KeyPair()
if err != nil {
return nil, err
} else if cert != nil {
tlsConfig.Certificates = []tls.Certificate{*cert}
}
// Check if we require verification
if c.VerifyIncoming {
tlsConfig.ClientAuth = tls.RequireAndVerifyClientCert
if c.CAFile == "" {
return nil, fmt.Errorf("VerifyIncoming set, and no CA certificate provided!")
}
if cert == nil {
return nil, fmt.Errorf("VerifyIncoming set, and no Cert/Key pair provided!")
}
}
return tlsConfig, nil
}
// DefaultConfig is used to return a sane default configuration
func DefaultConfig() *Config {
hostname, err := os.Hostname()
if err != nil {
panic(err)
}
conf := &Config{
Datacenter: DefaultDC,
NodeName: hostname,
RPCAddr: DefaultRPCAddr,
RaftConfig: raft.DefaultConfig(),
SerfLANConfig: serf.DefaultConfig(),
SerfWANConfig: serf.DefaultConfig(),
ReconcileInterval: 60 * time.Second,
ProtocolVersion: ProtocolVersionMax,
ACLTTL: 30 * time.Second,
ACLDefaultPolicy: "allow",
ACLDownPolicy: "extend-cache",
}
// Increase our reap interval to 3 days instead of 24h.
conf.SerfLANConfig.ReconnectTimeout = 3 * 24 * time.Hour
conf.SerfWANConfig.ReconnectTimeout = 3 * 24 * time.Hour
// WAN Serf should use the WAN timing, since we are using it
// to communicate between DC's
conf.SerfWANConfig.MemberlistConfig = memberlist.DefaultWANConfig()
// Ensure we don't have port conflicts
conf.SerfLANConfig.MemberlistConfig.BindPort = DefaultLANSerfPort
conf.SerfWANConfig.MemberlistConfig.BindPort = DefaultWANSerfPort
// Disable shutdown on removal
conf.RaftConfig.ShutdownOnRemove = false
return conf
}