Use per-source address configs

internal/perm/config.go

@@ -56,7 +56,7 @@ func (a Action) MarshalText() ([]byte, error) {
 	return []byte(name), nil
 }
 
-// Config is a list of address and actions.
+// Config is a list of address and actions, for each source address.
 // It can just be Marshal/Unmarshaled into/from json.
 type Config struct {
 	DefaultAction Action // What we should do when no action is matched.

internal/perm/perm.go

@@ -3,72 +3,96 @@ package perm
 import (
 	"net"
 	"strconv"
+	"strings"
 	"sync"
 )
 
+type int_perm struct {
+	match map[string]Action
+	def   Action
+}
+
 // Perm matches address:port strings to Actions
 // loaded from a Config.
 //
+// global permissions are stored under the "$global" address.
+//
 // It's thread safe.
 type Perm struct {
 	lock sync.RWMutex
 
-	perm map[string]Action
-	def  Action
+	global int_perm
+
+	source map[string]int_perm
 }
 
 // New creates a new Perm struct from a Config.
 //
 // You can also &perm.Perm{} and then call Load on it.
-func New(c *Config) (p *Perm) {
+func New(c map[string]Config) (p *Perm) {
 	p = &Perm{}
 	p.Load(c)
 	return
 }
 
 // Load loads/reloads the Perm struct.
-func (p *Perm) Load(c *Config) {
+func (p *Perm) Load(cs map[string]Config) {
 	p.lock.Lock()
 	defer p.lock.Unlock()
 
-	if p.perm == nil {
-		p.perm = make(map[string]Action)
+	if p.source == nil {
+		p.source = make(map[string]int_perm)
 	} else {
-		clear(p.perm)
+		clear(p.source)
 	}
 
-	p.def = c.DefaultAction
+	// helper to load every source addr
+	load_per_source := func(c Config) (p_int int_perm) {
+		p_int.match = make(map[string]Action)
+		p_int.def = c.DefaultAction
 
-	// insert helper to use the most severe action existing
-	insert := func(addrport string, action Action) {
-		existing_action, ok := p.perm[addrport]
-		if ok {
-			p.perm[addrport] = MostSevere(existing_action, action)
-		} else {
-			p.perm[addrport] = action
-		}
-	}
-
-	// loop around the Match map
-	for addrport, act := range c.Match {
-		addr, port := splitHostPort(addrport)
-		if port != "" {
-			insert(net.JoinHostPort(addr, port), act)
-		} else {
-			// so this is why def_port shouldn't be that big
-			// TODO change this to sth faster
-			for def_port := range c.DefaultPort {
-				insert(net.JoinHostPort(addr, strconv.Itoa(def_port)), act)
+		// insert helper to use the most severe action existing
+		insert := func(addrport string, action Action) {
+			existing_action, ok := p_int.match[addrport]
+			if ok {
+				p_int.match[addrport] = MostSevere(existing_action, action)
+			} else {
+				p_int.match[addrport] = action
 			}
 		}
+
+		// loop around the Match map
+		for addrport, act := range c.Match {
+			addr, port := splitHostPort(addrport)
+			if port != "" {
+				insert(net.JoinHostPort(addr, port), act)
+			} else {
+				// so this is why def_port shouldn't be that big
+				// TODO change this to sth faster
+				for def_port := range c.DefaultPort {
+					insert(net.JoinHostPort(addr, strconv.Itoa(def_port)), act)
+				}
+			}
+		}
+		return
+	}
+
+	for src, c := range cs {
+		if strings.EqualFold(src, "$global") {
+			p.global = load_per_source(c)
+		} else {
+			p.source[src] = load_per_source(c)
+		}
 	}
 
 	return
 }
 
 // Match matches an address to an action.
-// addr must be in net.JoinHostPort format.
-func (p *Perm) Match(addr string) Action {
+//
+// src must be a host (either ipv4 or v6), while
+// dest must be in net.JoinHostPort format.
+func (p *Perm) Match(src, dest string) Action {
 	// sanity check
 	if p == nil {
 		return ActionDeny
@@ -77,14 +101,28 @@ func (p *Perm) Match(addr string) Action {
 	p.lock.RLock()
 	defer p.lock.RUnlock()
 
-	// sanity check no.2
-	if p.perm == nil {
-		return p.def
+	// find its source struct
+	p_int, ok_int := p.source[src]
+	// only check if dest is directly listed
+	if ok_int && p_int.match != nil {
+		if action, ok := p_int.match[dest]; ok {
+			return action
+		}
 	}
 
-	action, ok := p.perm[addr]
-	if !ok {
-		return p.def
+	// then check the global struct, also only directly listed
+	if p.global.match != nil {
+		if action, ok := p.global.match[dest]; ok {
+			return action
+		}
+	}
+
+	// directly listed in neither.
+	if ok_int {
+		// if source struct exists, use source struct default.
+		return p_int.def
+	} else {
+		// if not exist, use global default.
+		return p.global.def
 	}
-	return action
 }