lib

Documentation

Index

• type Client
  • func (c *Client) EstablishTime(chain *config.Chain, quorum int, servers []config.Server, localAddr *snet.Addr) (TimeResult, error)
• type ServerInfo
• type TimeResult

Types

type Client

type Client struct {
	// Permutation returns a random permutation of [0‥n) that is used to
	// query servers in a random order. If nil, a sensible default is used.
	Permutation func(n int) []int

	// MaxRadiusUs is the maximum interval radius that will be accepted
	// from a server. If zero, a sensible default is used.
	MaxRadius time.Duration

	// MaxDifference is the maximum difference in time between any sample
	// from a server and the quorum-agreed time before that sample is
	// considered suspect. If zero, a sensible default is used.
	MaxDifference time.Duration

	// QueryTimeout is the amount of time a server has to reply to a query.
	// If zero, a sensible default will be used.
	QueryTimeout time.Duration

	// NumQueries is the maximum number of times a query will be sent to a
	// specific server before giving up. If <= zero, a sensible default
	// will be used.
	NumQueries int
	// contains filtered or unexported fields
}

Client represents a Roughtime client and exposes a number of members that can be set in order to configure it. The zero value of a Client is always ready to use and will set sensible defaults.

func (*Client) EstablishTime

func (c *Client) EstablishTime(chain *config.Chain, quorum int, servers []config.Server, localAddr *snet.Addr) (TimeResult, error)

EstablishTime queries a number of servers until it has a quorum of overlapping results, or it runs out of servers. Results from the querying the servers are appended to chain. TODO: Save local snet addr in Client object, remove from arguments

type ServerInfo

type ServerInfo struct {
	// QueryDuration is the amount of time that the server took to answer.
	QueryDuration time.Duration

	// Min and Max specify the time window given by the server. These
	// values have been adjusted so that they are comparible across
	// servers, even though they are queried at different times.
	Min, Max *big.Int
}

ServerInfo contains information from a specific server.

type TimeResult

type TimeResult struct {
	// MonoUTCDelta may be nil, in which case a time could not be
	// established. Otherwise it contains the difference between the
	// Roughtime epoch and the monotonic clock.
	MonoUTCDelta *time.Duration

	// ServerErrors maps from server name to query error.
	ServerErrors map[string]error

	// ServerInfo contains information about each server that was queried.
	ServerInfo map[string]ServerInfo

	// OutOfRangeAnswer is true if one or more of the queries contained a
	// significantly incorrect time, as defined by MaxDifference. In this
	// case, the reply will have been recorded in the chain.
	OutOfRangeAnswer bool

	// Overlapping midpoint time from server replies
	Midpoint *big.Int
}

TimeResult is the result of trying to establish the current time by querying a number of servers.