Basic filtering infrastructure.

Makefile

@@ -7,10 +7,10 @@ DEFINES = $(PLATFORM_DEFINES)
 CFLAGS = $(CDEBUGFLAGS) $(DEFINES) $(EXTRA_DEFINES)
 
 SRCS = babel.c net.c kernel.c util.c source.c neighbour.c \
-       route.c xroute.c message.c request.c
+       route.c xroute.c message.c request.c filter.c
 
 OBJS = babel.o net.o kernel.o util.o source.o neighbour.o \
-       route.o xroute.o message.o request.o
+       route.o xroute.o message.o request.o filter.o
 
 babel: $(OBJS)
 	$(CC) $(CFLAGS) $(LDFLAGS) -o babel $(OBJS) $(LDLIBS)

filter.c

+/*
+Copyright (c) 2007 by Juliusz Chroboczek
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+int
+import_filter(const unsigned char *id,
+              const unsigned char *prefix, unsigned short plen,
+              const unsigned char *nexthop)
+{
+    return 0;
+}
+
+int
+export_filter(const unsigned char *id,
+              const unsigned char *prefix, unsigned short plen)
+{
+    return 0;
+}
+

filter.h

+/*
+Copyright (c) 2007 by Juliusz Chroboczek
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+int import_filter(const unsigned char *id,
+                  const unsigned char *prefix, unsigned short plen,
+                  const unsigned char *nexthop);
+int export_filter(const unsigned char *id,
+                  const unsigned char *prefix, unsigned short plen);

message.c

@@ -36,6 +36,7 @@ THE SOFTWARE.
 #include "xroute.h"
 #include "request.h"
 #include "message.h"
+#include "filter.h"
 
 struct timeval update_flush_time = {0, 0};
 
@@ -522,15 +523,17 @@ really_send_update(struct network *net,
                    const unsigned char *prefix, unsigned char plen,
                    unsigned short seqno, unsigned short metric)
 {
-    if(in_prefix(address, prefix, plen)) {
-        send_message(net, 3, plen, 0, seqno, metric, address);
-    } else {
-        unsigned const char *sid;
-        start_message(net, 48);
-        sid = message_source_id(net);
-        if(sid == NULL || memcmp(address, sid, 16) != 0)
-            send_message(net, 3, 0xFF, 0, 0, 0xFFFF, address);
-        send_message(net, 4, plen, 0, seqno, metric, prefix);
+    if(!export_filter(address, prefix, plen)) {
+        if(in_prefix(address, prefix, plen)) {
+            send_message(net, 3, plen, 0, seqno, metric, address);
+        } else {
+            unsigned const char *sid;
+            start_message(net, 48);
+            sid = message_source_id(net);
+            if(sid == NULL || memcmp(address, sid, 16) != 0)
+                send_message(net, 3, 0xFF, 0, 0, 0xFFFF, address);
+            send_message(net, 4, plen, 0, seqno, metric, prefix);
+        }
     }
     satisfy_request(prefix, plen, seqno, hash_id(address), net);
 }

request.c

@@ -30,6 +30,7 @@ THE SOFTWARE.
 #include "neighbour.h"
 #include "request.h"
 #include "message.h"
+#include "filter.h"
 
 int request_resend_time = 0;
 struct request *recorded_requests = NULL;
@@ -69,6 +70,10 @@ record_request(const unsigned char *prefix, unsigned char plen,
 {
     struct request *request;
 
+    if(import_filter(NULL, prefix, plen, NULL) ||
+       export_filter(NULL, prefix, plen))
+        return 0;
+
     request = find_request(prefix, plen, NULL);
     if(request) {
         if(request->resend && resend)

route.c

@@ -35,6 +35,7 @@ THE SOFTWARE.
 #include "xroute.h"
 #include "message.h"
 #include "request.h"
+#include "filter.h"
 
 struct route routes[MAXROUTES];
 int numroutes = 0;
@@ -318,6 +319,9 @@ update_route(const unsigned char *a, const unsigned char *p, unsigned char plen,
         return NULL;
     }
 
+    if(import_filter(a, p, plen, nexthop->id))
+        return NULL;
+
     src = find_source(a, p, plen, 1, seqno);
     if(src == NULL)
         return NULL;