/
router_handle.go
290 lines (258 loc) · 6.79 KB
/
router_handle.go
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package router
import (
"context"
"math/rand/v2"
"net/netip"
"github.com/IrineSistiana/gopool"
"github.com/IrineSistiana/mosproxy/internal/dnsmsg"
"github.com/IrineSistiana/mosproxy/internal/pool"
)
func (r *Router) handleQueryAsync(q *dnsmsg.Msg, qm QueryMeta, w RespWriter) {
resp := r.handleQueryMsg(q, qm, w)
if resp != nil {
w.WriteResp(resp)
dnsmsg.ReleaseMsg(resp)
}
}
func (r *Router) handleQuerySync(q *dnsmsg.Msg, qm QueryMeta) *dnsmsg.Msg {
return r.handleQueryMsg(q, qm, nil)
}
// If w != nil, then it run blocking funcs asynchronously, and write resp to w, return nil.
// Otherwise, it returns resp.
func (r *Router) handleQueryMsg(q *dnsmsg.Msg, qMeta QueryMeta, w RespWriter) *dnsmsg.Msg {
resp, err := middlewareImpl().PreHandling(q, qMeta)
if err != nil {
r.logger.Warn().Err(err).Msg("middleware pre-handling error")
return makeEmptyRespM(q, dnsmsg.RCodeServerFailure)
}
if resp != nil {
postProcessResp(getQueryInfo(q), resp)
return resp
}
hdr := q.Header
notImpl := hdr.Response ||
!hdr.RecursionDesired ||
hdr.OpCode != dnsmsg.OpCode(0) ||
len(q.Questions) != 1
if notImpl {
e := r.logger.Debug()
if e != nil {
e.Stringer("remote", qMeta.RemoteAddr).
Stringer("local", qMeta.LocalAddr).
Msg("not impl query")
}
return makeEmptyRespM(q, dnsmsg.RCodeNotImplemented)
} else {
qc := qCtx{
uid: rand.Uint32(),
q: q.Questions[0].Copy(),
qMeta: qMeta,
qInfo: getQueryInfo(q)}
defer dnsmsg.ReleaseQuestion(qc.q)
dnsmsg.ToLowerName(qc.q.Name)
if r.opt.Log.TraceMsgs {
r.debugLogMsg(qc, q, "received query from client")
}
resp, meta := r.handleQuestion(qc, w)
if resp != nil {
postProcessResp(qc.qInfo, resp)
if r.opt.Log.Queries {
r.logQueryResp(qc, resp, meta)
}
if r.opt.Log.TraceMsgs {
r.debugLogMsg(qc, resp, "sending response to client")
}
}
return resp
}
}
func getQueryInfo(m *dnsmsg.Msg) QueryInfo {
i := QueryInfo{
Id: m.ID,
OpCode: m.OpCode,
Rd: m.RecursionDesired,
ECS: findECS(m),
}
for _, rr := range m.Additionals {
if rr.Hdr().Type == dnsmsg.TypeOPT {
i.EDNS0 = true
break
}
}
return i
}
// Set resp hdr.
// Set/remove resp edns0.
func postProcessResp(qInfo QueryInfo, resp *dnsmsg.Msg) {
resp.Header.ID = qInfo.Id
resp.Header.Response = true
resp.Header.OpCode = qInfo.OpCode
resp.Header.RecursionAvailable = true
resp.Header.RecursionDesired = qInfo.Rd
if qInfo.EDNS0 {
addOrReplaceOpt(resp, udpSize)
} else {
// remove opt from resp
rr := dnsmsg.PopEDNS0(resp)
if rr != nil {
dnsmsg.ReleaseResource(rr)
}
}
}
func (r *Router) handleQuestion(q qCtx, w RespWriter) (*dnsmsg.Msg, RespMeta) {
var remoteAddr netip.Addr
if usefulECS(q.qInfo.ECS) {
remoteAddr = q.qInfo.ECS.Addr()
} else {
remoteAddr = q.qMeta.RemoteAddr.Addr()
}
resp, upstream, respMeta := r.nonblockingFuncs(q, remoteAddr)
if resp != nil {
return resp, respMeta
}
if w != nil {
args := blockingJobArgs{
r: r,
q: qCtx{
uid: q.uid,
q: q.q.Copy(),
qMeta: q.qMeta,
qInfo: q.qInfo,
},
remoteAddr: remoteAddr,
respMeta: respMeta,
upstream: upstream,
w: w,
}
r.bJobPool.GoJob(gopool.Job[blockingJobArgs]{
Args: args,
Fn: doBlockingJob,
})
return nil, RespMeta{}
} else {
return r.blockingFuncs(qCtx{q: q.q, qMeta: q.qMeta, qInfo: q.qInfo}, remoteAddr, respMeta, upstream)
}
}
type blockingJobArgs struct {
r *Router
q qCtx
remoteAddr netip.Addr
respMeta RespMeta
upstream *upstreamWrapper
w RespWriter
}
func doBlockingJob(a blockingJobArgs) {
defer dnsmsg.ReleaseQuestion(a.q.q)
resp, meta := a.r.blockingFuncs(a.q, a.remoteAddr, a.respMeta, a.upstream)
defer dnsmsg.ReleaseMsg(resp)
postProcessResp(a.q.qInfo, resp)
if a.r.opt.Log.Queries {
a.r.logQueryResp(a.q, resp, meta)
}
if a.r.opt.Log.TraceMsgs {
a.r.debugLogMsg(a.q, resp, "sending response to client")
}
a.w.WriteResp(resp)
}
func usefulECS(p netip.Prefix) bool {
if !p.IsValid() {
return false
}
addr := p.Addr().Unmap()
bits := p.Bits()
if addr.Is4() {
return bits >= 24
}
return bits >= 48 // v6
}
// return (resp, nil, meta)
// or (nil, upstream, meta)
func (r *Router) nonblockingFuncs(q qCtx, remoteAddr netip.Addr) (*dnsmsg.Msg, *upstreamWrapper, RespMeta) {
var respMeta RespMeta
// Match rules
var matchedRule *rule
for i, rule := range r.rules {
matcher := rule.matcher.m.Load()
if matcher != nil {
matched := matcher.Match(q.q.Name)
if rule.reverse {
matched = !matched
}
if !matched {
continue
}
}
respMeta.RuleIdx = i
matchedRule = rule
break
}
if matchedRule == nil {
resp := makeEmptyRespMQ(q.q, uint16(dnsmsg.RCodeRefused))
return resp, nil, respMeta
}
if rejectRCode := matchedRule.reject; rejectRCode > 0 {
resp := makeEmptyRespMQ(q.q, rejectRCode)
return resp, nil, respMeta
}
if matchedRule.upstream == nil {
resp := makeEmptyRespMQ(q.q, uint16(dnsmsg.RCodeRefused))
return resp, nil, respMeta
}
upstream := matchedRule.upstream
// lookup cache
cacheKey, mark := r.cache.Key(q.q, remoteAddr)
respMeta.IpMark = mark
resp, storedTime, expireTime := r.cache.GetMemoryCache(cacheKey)
pool.ReleaseBuf(cacheKey)
if resp != nil { // mem cache hit
if needPrefetch(storedTime, expireTime) {
r.asyncSingleFlightPrefetch(q, remoteAddr, upstream)
}
r.queryCacheHitTotal.Inc()
r.limiterAllowN(remoteAddr, costFromCache)
respMeta.Cached = true
return resp, nil, respMeta
}
return nil, upstream, respMeta
}
// always returns a resp
func (r *Router) blockingFuncs(q qCtx, remoteAddr netip.Addr, respMeta RespMeta, upstream *upstreamWrapper) (*dnsmsg.Msg, RespMeta) {
ctx, cancel := context.WithTimeout(r.ctx, queryTimeout)
defer cancel()
cacheKey, _ := r.cache.Key(q.q, remoteAddr)
resp, storedTime, expireTime := r.cache.GetRedisCache(ctx, cacheKey)
pool.ReleaseBuf(cacheKey)
if resp != nil {
if needPrefetch(storedTime, expireTime) {
r.asyncSingleFlightPrefetch(q, remoteAddr, upstream)
}
r.queryCacheHitTotal.Inc()
r.limiterAllowN(remoteAddr, costFromCache)
respMeta.Cached = true
return resp, respMeta
}
if ctxDone(ctx) { // check if redis server timed out
resp := makeEmptyRespMQ(q.q, uint16(dnsmsg.RCodeServerFailure))
return resp, respMeta
}
r.limiterAllowN(remoteAddr, costFromUpstream)
resp, err := r.forward(ctx, q, remoteAddr, upstream)
if err != nil {
r.logger.Warn().
Str("upstream", upstream.tag).
Err(err).
Msg("failed to forward query")
resp := makeEmptyRespMQ(q.q, uint16(dnsmsg.RCodeServerFailure))
return resp, respMeta
}
err = middlewareImpl().PostForwarding(ctx, q.q, q.qMeta, q.qInfo, resp)
if err != nil {
dnsmsg.ReleaseMsg(resp)
r.logger.Warn().
Err(err).
Msg("postprocessor error")
return nil, respMeta
}
r.cache.Store(q.q, remoteAddr, resp)
return resp, respMeta
}