add pkgs from core

internal/util/matcher/matcher.go

@@ -0,0 +1,99 @@
+package matcher
+
+import (
+	"net"
+	"strings"
+
+	"github.com/gobwas/glob"
+)
+
+// Matcher is a generic pattern matcher,
+// it gives the match result of the given pattern for specific v.
+type Matcher interface {
+	Match(v string) bool
+}
+
+// NewMatcher creates a Matcher for the given pattern.
+// The acutal Matcher depends on the pattern:
+// IP Matcher if pattern is a valid IP address.
+// CIDR Matcher if pattern is a valid CIDR address.
+// Domain Matcher if both of the above are not.
+func NewMatcher(pattern string) Matcher {
+	if pattern == "" {
+		return nil
+	}
+	if ip := net.ParseIP(pattern); ip != nil {
+		return IPMatcher(ip)
+	}
+	if _, inet, err := net.ParseCIDR(pattern); err == nil {
+		return CIDRMatcher(inet)
+	}
+	return DomainMatcher(pattern)
+}
+
+type ipMatcher struct {
+	ip net.IP
+}
+
+// IPMatcher creates a Matcher for a specific IP address.
+func IPMatcher(ip net.IP) Matcher {
+	return &ipMatcher{
+		ip: ip,
+	}
+}
+
+func (m *ipMatcher) Match(ip string) bool {
+	if m == nil {
+		return false
+	}
+	return m.ip.Equal(net.ParseIP(ip))
+}
+
+type cidrMatcher struct {
+	ipNet *net.IPNet
+}
+
+// CIDRMatcher creates a Matcher for a specific CIDR notation IP address.
+func CIDRMatcher(inet *net.IPNet) Matcher {
+	return &cidrMatcher{
+		ipNet: inet,
+	}
+}
+
+func (m *cidrMatcher) Match(ip string) bool {
+	if m == nil || m.ipNet == nil {
+		return false
+	}
+	return m.ipNet.Contains(net.ParseIP(ip))
+}
+
+type domainMatcher struct {
+	pattern string
+	glob    glob.Glob
+}
+
+// DomainMatcher creates a Matcher for a specific domain pattern,
+// the pattern can be a plain domain such as 'example.com',
+// a wildcard such as '*.exmaple.com' or a special wildcard '.example.com'.
+func DomainMatcher(pattern string) Matcher {
+	p := pattern
+	if strings.HasPrefix(pattern, ".") {
+		p = pattern[1:] // trim the prefix '.'
+		pattern = "*" + p
+	}
+	return &domainMatcher{
+		pattern: p,
+		glob:    glob.MustCompile(pattern),
+	}
+}
+
+func (m *domainMatcher) Match(domain string) bool {
+	if m == nil || m.glob == nil {
+		return false
+	}
+
+	if domain == m.pattern {
+		return true
+	}
+	return m.glob.Match(domain)
+}