various: reduce file I/O & pre-parse CIDRs

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I288c299d35fdc833c802e22682f14b8e6a6a6964

internal/api/handler.go

@@ -5,6 +5,7 @@ import (
 	"net"
 	"net/http"
 	"strings"
+	"time"
 
 	"notashelf.dev/watchdog/internal/aggregate"
 	"notashelf.dev/watchdog/internal/config"
@@ -14,14 +15,16 @@ import (
 
 // Handles incoming analytics events
 type IngestionHandler struct {
-	cfg          *config.Config
-	domainMap    map[string]bool // O(1) domain validation
-	pathNorm     *normalize.PathNormalizer
-	pathRegistry *aggregate.PathRegistry
-	refRegistry  *normalize.ReferrerRegistry
-	metricsAgg   *aggregate.MetricsAggregator
-	rateLimiter  *ratelimit.TokenBucket
-	rng          *rand.Rand
+	cfg             *config.Config
+	domainMap       map[string]bool // O(1) domain validation
+	corsOriginMap   map[string]bool // O(1) CORS origin validation
+	pathNorm        *normalize.PathNormalizer
+	pathRegistry    *aggregate.PathRegistry
+	refRegistry     *normalize.ReferrerRegistry
+	metricsAgg      *aggregate.MetricsAggregator
+	rateLimiter     *ratelimit.TokenBucket
+	rng             *rand.Rand
+	trustedNetworks []*net.IPNet // Pre-parsed CIDR networks
 }
 
 // Creates a new ingestion handler
@@ -47,15 +50,40 @@ func NewIngestionHandler(
 		domainMap[domain] = true
 	}
 
+	// Build CORS origin map for O(1) lookup
+	corsOriginMap := make(map[string]bool, len(cfg.Security.CORS.AllowedOrigins))
+	for _, origin := range cfg.Security.CORS.AllowedOrigins {
+		corsOriginMap[origin] = true
+	}
+
+	// Pre-parse trusted proxy CIDRs to avoid re-parsing on each request
+	trustedNetworks := make([]*net.IPNet, 0, len(cfg.Security.TrustedProxies))
+	for _, cidr := range cfg.Security.TrustedProxies {
+		if _, network, err := net.ParseCIDR(cidr); err == nil {
+			trustedNetworks = append(trustedNetworks, network)
+		} else if ip := net.ParseIP(cidr); ip != nil {
+			// Single IP - create a /32 or /128 network
+			var mask net.IPMask
+			if ip.To4() != nil {
+				mask = net.CIDRMask(32, 32)
+			} else {
+				mask = net.CIDRMask(128, 128)
+			}
+			trustedNetworks = append(trustedNetworks, &net.IPNet{IP: ip, Mask: mask})
+		}
+	}
+
 	return &IngestionHandler{
-		cfg:          cfg,
-		domainMap:    domainMap,
-		pathNorm:     pathNorm,
-		pathRegistry: pathRegistry,
-		refRegistry:  refRegistry,
-		metricsAgg:   metricsAgg,
-		rateLimiter:  limiter,
-		rng:          rand.New(rand.NewSource(42)),
+		cfg:             cfg,
+		domainMap:       domainMap,
+		corsOriginMap:   corsOriginMap,
+		pathNorm:        pathNorm,
+		pathRegistry:    pathRegistry,
+		refRegistry:     refRegistry,
+		metricsAgg:      metricsAgg,
+		rateLimiter:     limiter,
+		rng:             rand.New(rand.NewSource(time.Now().UnixNano())),
+		trustedNetworks: trustedNetworks,
 	}
 }
 
@@ -213,13 +241,8 @@ func (h *IngestionHandler) extractIP(r *http.Request) string {
 
 	// Check if we should trust proxy headers
 	trustProxy := false
-	if len(h.cfg.Security.TrustedProxies) > 0 {
-		for _, trustedCIDR := range h.cfg.Security.TrustedProxies {
-			if h.ipInCIDR(remoteIP, trustedCIDR) {
-				trustProxy = true
-				break
-			}
-		}
+	if len(h.trustedNetworks) > 0 {
+		trustProxy = h.ipInNetworks(remoteIP, h.trustedNetworks)
 	}
 
 	// If not trusting proxy, return direct IP
@@ -233,10 +256,9 @@ func (h *IngestionHandler) extractIP(r *http.Request) string {
 		ips := strings.Split(xff, ",")
 		for i := len(ips) - 1; i >= 0; i-- {
 			ip := strings.TrimSpace(ips[i])
-			if !h.ipInCIDR(ip, "0.0.0.0/0") {
-				continue
+			if testIP := net.ParseIP(ip); testIP != nil {
+				return ip
 			}
-			return ip
 		}
 	}
 
@@ -249,26 +271,20 @@ func (h *IngestionHandler) extractIP(r *http.Request) string {
 	return remoteIP
 }
 
-// Checks if an IP address is within a CIDR range
-func (h *IngestionHandler) ipInCIDR(ip, cidr string) bool {
-	// Parse the IP address
+// Checks if an IP address is within any of the trusted networks
+func (h *IngestionHandler) ipInNetworks(ip string, networks []*net.IPNet) bool {
 	testIP := net.ParseIP(ip)
 	if testIP == nil {
 		return false
 	}
 
-	// Parse the CIDR
-	_, network, err := net.ParseCIDR(cidr)
-	if err != nil {
-		// If it's not a CIDR, try as a single IP
-		cidrIP := net.ParseIP(cidr)
-		if cidrIP == nil {
-			return false
+	for _, network := range networks {
+		if network.Contains(testIP) {
+			return true
 		}
-		return testIP.Equal(cidrIP)
 	}
 
-	return network.Contains(testIP)
+	return false
 }
 
 // Classifies device using both screen width and User-Agent parsing