diff options
Diffstat (limited to 'middleware/kubernetes/parse.go')
| -rw-r--r-- | middleware/kubernetes/parse.go | 121 |
1 files changed, 64 insertions, 57 deletions
diff --git a/middleware/kubernetes/parse.go b/middleware/kubernetes/parse.go index 700dc654a..4b09b15f9 100644 --- a/middleware/kubernetes/parse.go +++ b/middleware/kubernetes/parse.go @@ -13,80 +13,87 @@ type recordRequest struct { port string // The protocol is usually _udp or _tcp (if set), and comes from the protocol part of a well formed // SRV record. - protocol string - endpoint string - service string + protocol string + endpoint string + // The servicename used in Kubernetes. + service string + // The namespace used in Kubernetes. namespace string - // A each name can be for a pod or a service, here we track what we've seen. This value is true for - // pods and false for services. If we ever need to extend this well use a typed value. + // A each name can be for a pod or a service, here we track what we've seen, either "pod" or "service". podOrSvc string } -// parseRequest parses the qname to find all the elements we need for querying k8s. +// parseRequest parses the qname to find all the elements we need for querying k8s. Anything +// that is not parsed will have the wildcard "*" value (except r.endpoint). +// Potential underscores are stripped from _port and _protocol. func (k *Kubernetes) parseRequest(state request.Request) (r recordRequest, err error) { // 3 Possible cases: - // o SRV Request: _port._protocol.service.namespace.type.zone - // o A Request (endpoint): endpoint.service.namespace.type.zone - // o A Request (service): service.namespace.type.zone - // Federations are handled in the federation middleware. + // 1. _port._protocol.service.namespace.pod|svc.zone + // 2. (endpoint): endpoint.service.namespace.pod|svc.zone + // 3. (service): service.namespace.pod|svc.zone + // + // Federations are handled in the federation middleware. And aren't parsed here. base, _ := dnsutil.TrimZone(state.Name(), state.Zone) segs := dns.SplitDomainName(base) - offset := 0 - if state.QType() == dns.TypeSRV { - // The kubernetes peer-finder expects queries with empty port and service to resolve - // If neither is specified, treat it as a wildcard - if len(segs) == 3 { - r.port = "*" - r.service = "*" - offset = 0 - } else { - if len(segs) != 5 { - return r, errInvalidRequest - } - // This is a SRV style request, get first two elements as port and - // protocol, stripping leading underscores if present. - if segs[0][0] == '_' { - r.port = segs[0][1:] - } else { - r.port = segs[0] - if !wildcard(r.port) { - return r, errInvalidRequest - } - } - if segs[1][0] == '_' { - r.protocol = segs[1][1:] - if r.protocol != "tcp" && r.protocol != "udp" { - return r, errInvalidRequest - } - } else { - r.protocol = segs[1] - if !wildcard(r.protocol) { - return r, errInvalidRequest - } - } - if r.port == "" || r.protocol == "" { - return r, errInvalidRequest - } - offset = 2 - } + r.port = "*" + r.protocol = "*" + r.service = "*" + r.namespace = "*" + // r.endpoint is the odd one out, we need to know if it has been set or not. If it is + // empty we should skip the endpoint check in k.get(). Hence we cannot set if to "*". + + // start at the right and fill out recordRequest with the bits we find, so we look for + // pod|svc.namespace.service and then either + // * endpoint + // *_protocol._port + + last := len(segs) - 1 + r.podOrSvc = segs[last] + if r.podOrSvc != Pod && r.podOrSvc != Svc { + return r, errInvalidRequest } - if (state.QType() == dns.TypeA || state.QType() == dns.TypeAAAA) && len(segs) == 4 { - // This is an endpoint A/AAAA record request. Get first element as endpoint. - r.endpoint = segs[0] - offset = 1 + last-- + if last < 0 { + return r, nil } - if len(segs) == (offset + 3) { - r.service = segs[offset] - r.namespace = segs[offset+1] - r.podOrSvc = segs[offset+2] + r.namespace = segs[last] + last-- + if last < 0 { + return r, nil + } + r.service = segs[last] + last-- + if last < 0 { return r, nil } - return r, errInvalidRequest + // Becuase of ambiquity we check the labels left: 1: an endpoint. 2: port and protocol. + // Anything else is a query that is too long to answer and can safely be delegated to return an nxdomain. + switch last { + + case 0: // endpoint only + r.endpoint = segs[last] + case 1: // service and port + r.protocol = stripUnderscore(segs[last]) + r.port = stripUnderscore(segs[last-1]) + + default: // too long + return r, errInvalidRequest + } + + return r, nil +} + +// stripUnderscore removes a prefixed underscore from s. +func stripUnderscore(s string) string { + if s[0] != '_' { + return s + } + return s[1:] } // String return a string representation of r, it just returns all fields concatenated with dots. |