upterm

const (
	// host
	HostSSHClientVersion  = "SSH-2.0-upterm-host-client"
	HostSSHServerVersion  = "SSH-2.0-upterm-host-server"
	HostAdminSocketEnvVar = "UPTERM_ADMIN_SOCKET"
	HostSessionNameEnvVar = "UPTERM_SESSION_NAME"

	// client
	ClientSSHClientVersion  = "SSH-2.0-upterm-client-client"
	AttachSSHClientVersion  = "SSH-2.0-upterm-attach"
	AttachInteractiveEnvVar = "UPTERM_ATTACH_INTERACTIVE"

	// server
	ServerSSHServerVersion         = "SSH-2.0-uptermd"
	ServerServerInfoRequestType    = "upterm-server-info@upterm.dev"
	ServerCreateSessionRequestType = "upterm-create-session@upterm.dev"

	// header
	HeaderUptermClientVersion = "Upterm-Client-Version"

	// misc
	OpenSSHKeepAliveRequestType = "keepalive@openssh.com"

	SSHCertExtension = "upterm-auth-request"

	EventClientJoined = "client-joined"
	EventClientLeft   = "client-left"

	// Forwarding presence is visible, but does not qualify as a first guest join.
	EventForwardingClientJoined = "forwarding-client-joined"
)

const (
	// BannerNoHostFormat is sent, with the session ID, when no host is
	// connected for the session. join matches it by BannerNoHostPrefix.
	BannerNoHostFormat = "upterm: no host is connected for session %s right now. " +
		"If it is reconnecting, this same ssh command will work again once it's back. " +
		"Try again in a few seconds.\n"
	BannerNoHostPrefix = "upterm: no host is connected for session "
	// BannerLookupFailed is sent when the relay's session store failed.
	BannerLookupFailed = "upterm: the relay can't look up sessions right now. Try again shortly.\n"

	// The messages of a rejected session channel, when the relay completed a
	// guest's handshake and then failed upstream (server/sshstock.go,
	// upstreamFailureReason).
	UpstreamUnavailable     = "upstream unavailable"
	UpstreamAuthFailed      = "ssh: unable to authenticate with the upstream"
	UpstreamHostKeyMismatch = "ssh: host key mismatch"
	// The next hop's verdict, kept: the relay node that receives the session
	// node's banner turns it into one of these. A node that predates these
	// verdicts reports UpstreamAuthFailed instead, which therefore stays
	// ambiguous: "refused, or no session". Nodes nearer the guest forward a
	// converted verdict unchanged, older ones included.
	UpstreamNoHost       = "upstream has no session"
	UpstreamLookupFailed = "upstream can't look up sessions"
	UpstreamKeyRefused   = "upstream refused the key"

	// HopBannerKeyRefused is what the node holding a session sends another
	// relay node, never a guest, when it refuses the key that node presents.
	// It is read only by relays; no person sees it.
	HopBannerKeyRefused = "upterm-hop: key refused\n"

	// JoinSSHClientVersion is upterm join's SSH version string. The relay
	// treats anything but the exact HostSSHClientVersion as a guest.
	JoinSSHClientVersion = "SSH-2.0-upterm-join"
)