Implement forwarding of replies.

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
+       route.c xroute.c message.c request.c
 
 OBJS = babel.o net.o kernel.o util.o source.o neighbour.o \
-       route.o xroute.o message.o
+       route.o xroute.o message.o request.o
 
 babel: $(OBJS)
 	$(CC) $(CFLAGS) $(LDFLAGS) -o babel $(OBJS) $(LDLIBS)

babel.c

@@ -47,6 +47,7 @@ THE SOFTWARE.
 #include "route.h"
 #include "xroute.h"
 #include "message.h"
+#include "request.h"
 
 struct timeval now;
 
@@ -497,6 +498,7 @@ main(int argc, char **argv)
 
         if(now.tv_sec >= expiry_time) {
             expire_routes();
+            expire_requests();
             expiry_time = now.tv_sec + 20 + random() % 20;
         }
 

message.c

@@ -34,6 +34,7 @@ THE SOFTWARE.
 #include "neighbour.h"
 #include "route.h"
 #include "xroute.h"
+#include "request.h"
 #include "message.h"
 
 struct timeval update_flush_time = {0, 0};
@@ -248,7 +249,8 @@ handle_request(struct neighbour *neigh, const unsigned char *prefix,
             if(hop_count > 1) {
                 send_unicast_request(route->nexthop, prefix, plen,
                                      hop_count - 1, seqno, router_hash);
-                /* We should record sending this request at this point. */
+                record_request(prefix, plen, seqno, router_hash,
+                               neigh->network);
             }
         } else {
             send_update(neigh->network, 1, prefix, plen);
@@ -512,7 +514,8 @@ static void
 really_send_update(struct network *net,
                    const unsigned char *address,
                    const unsigned char *prefix, unsigned char plen,
-                   unsigned short seqno, unsigned short metric)
+                   unsigned short seqno, unsigned short metric,
+                   unsigned short router_hash)
 {
     if(in_prefix(address, prefix, plen)) {
         send_message(net, 3, plen, 0, seqno, metric, address);
@@ -524,6 +527,7 @@ really_send_update(struct network *net,
             send_message(net, 3, 0xFF, 0, 0, 0xFFFF, address);
         send_message(net, 4, plen, 0, seqno, metric, prefix);
     }
+    satisfy_request(prefix, plen, seqno, router_hash, net);
 }
 
 void
@@ -551,7 +555,8 @@ flushupdates(void)
             if(xroute) {
                 really_send_update(net, myid,
                                    xroute->prefix, xroute->plen,
-                                   myseqno, xroute->metric);
+                                   myseqno, xroute->metric,
+                                   hash_id(myid));
                 continue;
             }
             route = find_installed_route(buffered_updates[i].prefix,
@@ -565,7 +570,8 @@ flushupdates(void)
                 really_send_update(net, route->src->address,
                                    route->src->prefix,
                                    route->src->plen,
-                                   seqno, metric);
+                                   seqno, metric,
+                                   hash_id(route->src->address));
                 update_source(route->src, seqno, metric);
                 continue;
             }
@@ -575,7 +581,7 @@ flushupdates(void)
                 really_send_update(net, src->address, src->prefix, src->plen,
                                    src->metric >= INFINITY ?
                                    src->seqno : seqno_plus(src->seqno, 1),
-                                   INFINITY);
+                                   INFINITY, hash_id(src->address));
                 continue;
             }
         }
@@ -628,6 +634,20 @@ send_update(struct network *net, int urgent,
             const unsigned char *prefix, unsigned char plen)
 {
     int i;
+    struct request *request;
+
+    /* This is needed here, since really_send_update only handles the
+       case where network is not null. */
+    request = find_request(prefix, plen, NULL);
+    if(request) {
+        struct route *route;
+        route = find_installed_route(prefix, plen);
+        if(route) {
+            urgent = 1;
+            satisfy_request(prefix, plen, route->seqno,
+                            hash_id(route->src->address), net);
+        }
+    }
 
     if(net == NULL) {
         for(i = 0; i < numnets; i++)
@@ -722,7 +742,7 @@ send_self_retract(struct network *net)
     for(i = 0; i < numxroutes; i++) {
         if(xroutes[i].exported)
             really_send_update(net, myid, xroutes[i].prefix, xroutes[i].plen,
-                               myseqno, 0xFFFF);
+                               myseqno, 0xFFFF, hash_id(myid));
     }
     schedule_update_flush(net, 1);
 }

request.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.
+*/
+
+#include <sys/time.h>
+#include <time.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "babel.h"
+#include "util.h"
+#include "neighbour.h"
+#include "request.h"
+
+struct request *recorded_requests = NULL;
+
+static int
+request_match(struct request *request,
+              const unsigned char *prefix, unsigned char plen)
+{
+    return request->plen == plen && memcmp(request->prefix, prefix, 16) == 0;
+}
+
+struct request *
+find_request(const unsigned char *prefix, unsigned char plen,
+             struct request **previous_return)
+{
+    struct request *request, *previous;
+
+    previous = NULL;
+    request = recorded_requests;
+    while(request) {
+        if(request_match(request, prefix, plen)) {
+            if(previous_return)
+                *previous_return = previous;
+            return request;
+        }
+        previous = request;
+        request = request->next;
+    }
+
+    return NULL;
+}
+
+int
+record_request(const unsigned char *prefix, unsigned char plen,
+               unsigned short seqno, unsigned short router_hash,
+               struct network *network)
+{
+    struct request *request;
+
+    request = find_request(prefix, plen, NULL);
+    if(request) {
+        if(request->router_hash == router_hash ||
+           seqno_compare(request->seqno, seqno) > 0) {
+            return 0;
+        } else {
+            request->router_hash = router_hash;
+            request->seqno = seqno;
+            request->time = now.tv_sec;
+            if(request->network != network)
+                request->network = NULL;
+            return 1;
+        }
+    } else {
+        request = malloc(sizeof(struct request));
+        if(request == NULL)
+            return -1;
+        memcpy(request->prefix, prefix, 16);
+        request->plen = plen;
+        request->seqno = seqno;
+        request->router_hash = router_hash;
+        request->time = now.tv_sec;
+        request->network = network;
+        request->next = recorded_requests;
+        recorded_requests = request;
+        return 1;
+    }
+}
+
+int
+satisfy_request(const unsigned char *prefix, unsigned char plen,
+                unsigned short seqno, unsigned short router_hash,
+                struct network *network)
+{
+    struct request *request, *previous;
+
+    request = find_request(prefix, plen, &previous);
+    if(request == NULL)
+        return 0;
+
+    if(network != NULL && request->network != network)
+        return 0;
+
+    if(request->router_hash != router_hash ||
+       seqno_compare(request->seqno, seqno) <= 0) {
+        if(previous == NULL)
+            recorded_requests = request->next;
+        else
+            previous->next = request->next;
+        free(request);
+        return 1;
+    }
+
+    return 0;
+
+    
+}
+
+void
+expire_requests()
+{
+    struct request *request, *previous;
+
+    previous = NULL;
+    request = recorded_requests;
+    while(request) {
+        if(request->time < now.tv_sec - 60) {
+            if(previous == NULL) {
+                recorded_requests = request->next;
+                request = recorded_requests;
+            } else {
+                previous->next = request->next;
+                request = previous->next;
+            }
+            free(request);
+        } else {
+            request = request->next;
+        }
+    }
+}
+

request.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.
+*/
+
+struct request {
+    unsigned char prefix[16];
+    unsigned char plen;
+    unsigned short seqno;
+    unsigned short router_hash;
+    struct network *network;
+    int time;
+    struct request *next;
+};
+
+struct request *find_request(const unsigned char *prefix, unsigned char plen,
+                             struct request **previous_return);
+int record_request(const unsigned char *prefix, unsigned char plen,
+                   unsigned short seqno, unsigned short router_hash,
+                   struct network *net);
+int satisfy_request(const unsigned char *prefix, unsigned char plen,
+                    unsigned short seqno, unsigned short router_hash,
+                    struct network *net);
+
+void expire_requests(void);
+
+

route.c

@@ -34,6 +34,7 @@ THE SOFTWARE.
 #include "route.h"
 #include "xroute.h"
 #include "message.h"
+#include "request.h"
 
 struct route routes[MAXROUTES];
 int numroutes = 0;
@@ -452,7 +453,8 @@ send_triggered_update(struct route *route, struct source *oldsrc, int oldmetric)
     /* Switching sources can cause transient routing loops, so always send
        updates in that case.  Retractions are always urgent. */
     urgent = (route->src != oldsrc) ||
-        (oldmetric < INFINITY && newmetric >= INFINITY);
+        (oldmetric < INFINITY && newmetric >= INFINITY) ||
+        find_request(route->src->prefix, route->src->plen, NULL);
 
     if(urgent ||
        (newmetric >= oldmetric + 256 || oldmetric >= newmetric + 256))