Fix: legacy clients expect ssh_session_id in handshake response

psiphon/common/protocol.go

@@ -81,6 +81,7 @@ func TunnelProtocolUsesMeekHTTPS(protocol string) bool {
 }
 
 type HandshakeResponse struct {
+	SSHSessionID         string              `json:"ssh_session_id"`
 	Homepages            []string            `json:"homepages"`
 	UpgradeClientVersion string              `json:"upgrade_client_version"`
 	PageViewRegexes      []map[string]string `json:"page_view_regexes"`

psiphon/server/api.go

@@ -169,6 +169,7 @@ func handshakeAPIRequestHandler(
 	// Note: no guarantee that PsinetDatabase won't reload between database calls
 	db := support.PsinetDatabase
 	handshakeResponse := common.HandshakeResponse{
+		SSHSessionID:         sessionID,
 		Homepages:            db.GetRandomHomepage(sponsorID, geoIPData.Country, isMobile),
 		UpgradeClientVersion: db.GetUpgradeClientVersion(clientVersion, normalizedPlatform),
 		PageViewRegexes:      make([]map[string]string, 0),