init

2026-07-24 13:29:16 +00:00
commit 2275bd7dc4
29 changed files with 3641 additions and 0 deletions
@@ -0,0 +1,111 @@
+package engine
+
+import (
+	"github.com/sagernet/sing-box/option"
+)
+
+func dnsActionOf(r option.DNSRule) actionInfo {
+	var a option.DNSRuleAction
+	if r.Type == "logical" {
+		a = r.LogicalOptions.DNSRuleAction
+	} else {
+		a = r.DefaultOptions.DNSRuleAction
+	}
+	typ := a.Action
+	if typ == "" {
+		typ = "route"
+	}
+	ai := actionInfo{typ: typ}
+	switch typ {
+	case "route":
+		ai.server = a.RouteOptions.Server
+		ai.terminal = true
+		ai.detail = "route → server " + orDefault(ai.server, "(default)")
+	case "route-options":
+		ai.detail = "route-options (non-terminal)"
+	case "reject":
+		m := a.RejectOptions.Method
+		if m == "" {
+			m = "default"
+		}
+		ai.terminal = true
+		ai.detail = "reject (" + m + ")"
+	case "predefined":
+		ai.terminal = true
+		ai.detail = "predefined response"
+	case "evaluate":
+		ai.server = a.RouteOptions.Server
+		ai.detail = "evaluate (non-terminal)"
+	case "respond":
+		ai.terminal = true
+		ai.detail = "respond"
+	default:
+		ai.terminal = true
+		ai.detail = typ
+	}
+	return ai
+}
+
+// matchDNS evaluates DNS rules for the host to determine which DNS server / DNS
+// rule action is hit. Evaluated for A queries (the common resolution path).
+func (ec *evalCtx) matchDNS(cfg *Config) *DNSTrace {
+	prevQT := ec.queryType
+	ec.queryType = 1 // dns.TypeA
+	defer func() { ec.queryType = prevQT }()
+
+	tr := &DNSTrace{QueryType: "A", MatchedIndex: -1, Final: cfg.effectiveDNSFinal()}
+	hadConditional := false
+
+	for i, r := range cfg.DNSRules {
+		re := ec.evalDNSRuleNode(r)
+		re.Index = i
+		re.Reached = true
+		a := dnsActionOf(r)
+		re.ActionType = a.typ
+		re.ActionText = a.detail
+		re.Terminal = a.terminal
+
+		switch re.Status {
+		case StatusMatch:
+			if !a.terminal {
+				re.Effect = "matched but non-terminal; continues scanning"
+				tr.Steps = append(tr.Steps, re)
+				continue
+			}
+			tr.Steps = append(tr.Steps, re)
+			tr.MatchedIndex = i
+			tr.Decision = ec.dnsDecision(cfg, a, false, hadConditional)
+			return tr
+		case StatusUnknown:
+			if a.terminal {
+				re.Effect = "could match here if its undetermined conditions hold"
+				hadConditional = true
+			}
+			tr.Steps = append(tr.Steps, re)
+		default:
+			tr.Steps = append(tr.Steps, re)
+		}
+	}
+
+	// Fall through to dns.final.
+	final := cfg.effectiveDNSFinal()
+	tr.Decision = ec.dnsDecision(cfg, actionInfo{typ: "route", server: final, terminal: true, detail: "route → server " + orDefault(final, "(first server)")}, true, hadConditional)
+	if len(cfg.DNSRules) == 0 {
+		tr.Note = "no DNS rules; the final server is always used"
+	}
+	return tr
+}
+
+func (ec *evalCtx) dnsDecision(cfg *Config, a actionInfo, fromFinal, assumed bool) *DNSDecision {
+	d := &DNSDecision{
+		ActionType: a.typ,
+		Server:     a.server,
+		Detail:     a.detail,
+		FromFinal:  fromFinal,
+		Assumed:    assumed,
+	}
+	if a.server != "" {
+		d.ServerInfo = cfg.findDNSServer(a.server)
+	}
+	return d
+}