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Diffstat (limited to 'middleware/autopath/autopath.go')
-rw-r--r--middleware/autopath/autopath.go152
1 files changed, 0 insertions, 152 deletions
diff --git a/middleware/autopath/autopath.go b/middleware/autopath/autopath.go
deleted file mode 100644
index 94db8bc56..000000000
--- a/middleware/autopath/autopath.go
+++ /dev/null
@@ -1,152 +0,0 @@
-/*
-Package autopath implements autopathing. This is a hack; it shortcuts the
-client's search path resolution by performing these lookups on the server...
-
-The server has a copy (via AutoPathFunc) of the client's search path and on
-receiving a query it first establish if the suffix matches the FIRST configured
-element. If no match can be found the query will be forwarded up the middleware
-chain without interference (iff 'fallthrough' has been set).
-
-If the query is deemed to fall in the search path the server will perform the
-queries with each element of the search path appended in sequence until a
-non-NXDOMAIN answer has been found. That reply will then be returned to the
-client - with some CNAME hackery to let the client accept the reply.
-
-If all queries return NXDOMAIN we return the original as-is and let the client
-continue searching. The client will go to the next element in the search path,
-but we won’t do any more autopathing. It means that in the failure case, you do
-more work, since the server looks it up, then the client still needs to go
-through the search path.
-
-It is assume the search path ordering is identical between server and client.
-
-Midldeware implementing autopath, must have a function called `AutoPath` of type
-autopath.Func. Note the searchpath must be ending with the empty string.
-
-I.e:
-
-func (m Middleware ) AutoPath(state request.Request) []string {
- return []string{"first", "second", "last", ""}
-}
-*/
-package autopath
-
-import (
- "log"
-
- "github.com/coredns/coredns/middleware"
- "github.com/coredns/coredns/middleware/pkg/dnsutil"
- "github.com/coredns/coredns/middleware/pkg/nonwriter"
- "github.com/coredns/coredns/request"
-
- "github.com/miekg/dns"
- "golang.org/x/net/context"
-)
-
-// Func defines the function middleware should implement to return a search
-// path to the autopath middleware. The last element of the slice must be the empty string.
-// If Func returns a nil slice, no autopathing will be done.
-type Func func(request.Request) []string
-
-// AutoPath perform autopath: service side search path completion.
-type AutoPath struct {
- Next middleware.Handler
- Zones []string
-
- // Search always includes "" as the last element, so we try the base query with out any search paths added as well.
- search []string
- searchFunc Func
-}
-
-// ServeDNS implements the middleware.Handle interface.
-func (a *AutoPath) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
- state := request.Request{W: w, Req: r}
-
- zone := middleware.Zones(a.Zones).Matches(state.Name())
- if zone == "" {
- return middleware.NextOrFailure(a.Name(), a.Next, ctx, w, r)
- }
-
- // Check if autopath should be done, searchFunc takes precedence over the local configured search path.
- var err error
- searchpath := a.search
-
- if a.searchFunc != nil {
- searchpath = a.searchFunc(state)
- }
-
- if len(searchpath) == 0 {
- log.Printf("[WARNING] No search path available for autopath")
- return middleware.NextOrFailure(a.Name(), a.Next, ctx, w, r)
- }
-
- if !firstInSearchPath(state.Name(), searchpath) {
- return middleware.NextOrFailure(a.Name(), a.Next, ctx, w, r)
- }
-
- origQName := state.QName()
-
- // Establish base name of the query. I.e what was originally asked.
- base, err := dnsutil.TrimZone(state.QName(), searchpath[0]) // TODO(miek): we loose the original case of the query here.
- if err != nil {
- return dns.RcodeServerFailure, err
- }
-
- firstReply := new(dns.Msg)
- firstRcode := 0
- var firstErr error
-
- ar := r.Copy()
- // Walk the search path and see if we can get a non-nxdomain - if they all fail we return the first
- // query we've done and return that as-is. This means the client will do the search path walk again...
- for i, s := range searchpath {
- newQName := base + "." + s
- ar.Question[0].Name = newQName
- nw := nonwriter.New(w)
-
- rcode, err := middleware.NextOrFailure(a.Name(), a.Next, ctx, nw, ar)
- if err != nil {
- // Return now - not sure if this is the best. We should also check if the write has happened.
- return rcode, err
- }
- if i == 0 {
- firstReply = nw.Msg
- firstRcode = rcode
- firstErr = err
- }
-
- if !middleware.ClientWrite(rcode) {
- continue
- }
-
- if nw.Msg.Rcode == dns.RcodeNameError {
- continue
- }
-
- msg := nw.Msg
- cnamer(msg, origQName)
-
- // Write whatever non-nxdomain answer we've found.
- w.WriteMsg(msg)
- return rcode, err
-
- }
- if middleware.ClientWrite(firstRcode) {
- w.WriteMsg(firstReply)
- }
- return firstRcode, firstErr
-}
-
-// Name implements the Handler interface.
-func (a *AutoPath) Name() string { return "autopath" }
-
-// firstInSearchPath checks if name is equal to are a sibling of the first element in the search path.
-func firstInSearchPath(name string, searchpath []string) bool {
- if name == searchpath[0] {
- return true
- }
- if dns.IsSubDomain(searchpath[0], name) {
- return true
- }
- return false
-}