* add todo list

* beef up packet scheduler


git-svn-id: file:///home/lennart/svn/public/avahi/trunk@18 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 217 insertions, 59 deletions

diff --git a/psched.c b/psched.c
index db72ec3..162c1b2 100644
--- a/psched.c
+++ b/psched.c
@@ -1,6 +1,14 @@
+#include <string.h>
+
 #include "util.h"
 #include "psched.h"
 
+#define FLX_QUERY_HISTORY_MSEC 700
+#define FLX_QUERY_DEFER_MSEC 100
+#define FLX_RESPONSE_HISTORY_MSEC 700
+#define FLX_RESPONSE_DEFER_MSEC 20
+#define FLX_RESPONSE_JITTER_MSEC 100
+
 flxPacketScheduler *flx_packet_scheduler_new(flxServer *server, flxInterface *i) {
     flxPacketScheduler *s;
 
@@ -68,9 +76,11 @@ static guint8* packet_add_query_job(flxPacketScheduler *s, flxDnsPacket *p, flxQ
 
         qj->done = 1;
 
-        /* Drop query after 100ms from history */
-        flx_elapse_time(&tv, 100, 0);
+        /* Drop query after some time from history from history */
+        flx_elapse_time(&tv, FLX_QUERY_HISTORY_MSEC, 0);
         flx_time_event_queue_update(s->server->time_event_queue, qj->time_event, &tv);
+
+        g_get_current_time(&qj->delivery);
     }
 
     return d;
@@ -127,25 +137,47 @@ static flxQueryJob* look_for_query(flxPacketScheduler *s, flxKey *key) {
     return NULL;
 }
 
-void flx_packet_scheduler_post_query(flxPacketScheduler *s, flxKey *key) {
+flxQueryJob* query_job_new(flxPacketScheduler *s, flxKey *key) {
     flxQueryJob *qj;
-    GTimeVal tv;
     
     g_assert(s);
     g_assert(key);
 
-    if (look_for_query(s, key))
-        return;
-
     qj = g_new(flxQueryJob, 1);
+    qj->scheduler = s;
     qj->key = flx_key_ref(key);
     qj->done = FALSE;
+    qj->time_event = NULL;
+    
+    FLX_LLIST_PREPEND(flxQueryJob, jobs, s->query_jobs, qj);
 
-    flx_elapse_time(&tv, 100, 0);
-    qj->time_event = flx_time_event_queue_add(s->server->time_event_queue, &tv, query_elapse, qj);
-    qj->scheduler = s;
+    return qj;
+}
 
-    FLX_LLIST_PREPEND(flxQueryJob, jobs, s->query_jobs, qj);
+void flx_packet_scheduler_post_query(flxPacketScheduler *s, flxKey *key, gboolean immediately) {
+    GTimeVal tv;
+    flxQueryJob *qj;
+    
+    g_assert(s);
+    g_assert(key);
+
+    flx_elapse_time(&tv, immediately ? 0 : FLX_QUERY_DEFER_MSEC, 0);
+    
+    if ((qj = look_for_query(s, key))) {
+        glong d = flx_timeval_diff(&tv, &qj->delivery);
+
+        /* Duplicate questions suppression */
+        if (d >= 0 && d <= FLX_QUERY_HISTORY_MSEC*1000) {
+            g_message("WARNING! DUPLICATE QUERY SUPPRESSION ACTIVE!");
+            return;
+        }
+
+        query_job_free(s, qj);
+    }
+
+    qj = query_job_new(s, key);
+    qj->delivery = tv;
+    qj->time_event = flx_time_event_queue_add(s->server->time_event_queue, &qj->delivery, query_elapse, qj);
 }
 
 static guint8* packet_add_response_job(flxPacketScheduler *s, flxDnsPacket *p, flxResponseJob *rj) {
@@ -160,35 +192,32 @@ static guint8* packet_add_response_job(flxPacketScheduler *s, flxDnsPacket *p, f
 
         rj->done = 1;
 
-        /* Drop response after 1s from history */
-        flx_elapse_time(&tv, 1000, 0);
+        /* Drop response after some time from history */
+        flx_elapse_time(&tv, FLX_RESPONSE_HISTORY_MSEC, 0);
         flx_time_event_queue_update(s->server->time_event_queue, rj->time_event, &tv);
+
+        g_get_current_time(&rj->delivery);
     }
 
     return d;
 }
-                                 
 
-static void response_elapse(flxTimeEvent *e, gpointer data) {
-    flxResponseJob *rj = data;
-    flxPacketScheduler *s;
+static void send_response_packet(flxPacketScheduler *s, flxResponseJob *rj) {
     flxDnsPacket *p;
     guint n;
-    guint8 *d;
-
-    g_assert(rj);
-    s = rj->scheduler;
 
-    if (rj->done) {
-        /* Lets remove it  from the history */
-        response_job_free(s, rj);
-        return;
-    }
+    g_assert(s);
 
     p = flx_dns_packet_new_response(s->interface->hardware->mtu - 200);
-    d = packet_add_response_job(s, p, rj);
-    g_assert(d);
-    n = 1;
+    n = 0;
+
+    /* If a job was specified, put it in the packet. */
+    if (rj) {
+        guint8 *d;
+        d = packet_add_response_job(s, p, rj);
+        g_assert(d);
+        n++;
+    }
 
     /* Try to fill up packet with more responses, if available */
     for (rj = s->response_jobs; rj; rj = rj->jobs_next) {
@@ -207,6 +236,22 @@ static void response_elapse(flxTimeEvent *e, gpointer data) {
     flx_dns_packet_free(p);
 }
 
+static void response_elapse(flxTimeEvent *e, gpointer data) {
+    flxResponseJob *rj = data;
+    flxPacketScheduler *s;
+
+    g_assert(rj);
+    s = rj->scheduler;
+
+    if (rj->done) {
+        /* Lets remove it  from the history */
+        response_job_free(s, rj);
+        return;
+    }
+
+    send_response_packet(s, rj);
+}
+
 static flxResponseJob* look_for_response(flxPacketScheduler *s, flxRecord *record) {
     flxResponseJob *rj;
 
@@ -220,67 +265,180 @@ static flxResponseJob* look_for_response(flxPacketScheduler *s, flxRecord *recor
     return NULL;
 }
 
-void flx_packet_scheduler_post_response(flxPacketScheduler *s, flxRecord *record) {
+static flxResponseJob* response_job_new(flxPacketScheduler *s, flxRecord *record) {
     flxResponseJob *rj;
-    GTimeVal tv;
     
     g_assert(s);
     g_assert(record);
 
-    if (look_for_response(s, record))
-        return;
-
     rj = g_new(flxResponseJob, 1);
+    rj->scheduler = s;
     rj->record = flx_record_ref(record);
     rj->done = FALSE;
+    rj->time_event = NULL;
+    
+    FLX_LLIST_PREPEND(flxResponseJob, jobs, s->response_jobs, rj);
 
-    flx_elapse_time(&tv, 20, 100);
-    rj->time_event = flx_time_event_queue_add(s->server->time_event_queue, &tv, response_elapse, rj);
-    rj->scheduler = s;
+    return rj;
+}
 
-    FLX_LLIST_PREPEND(flxResponseJob, jobs, s->response_jobs, rj);
+void flx_packet_scheduler_post_response(flxPacketScheduler *s, flxRecord *record, gboolean immediately) {
+    flxResponseJob *rj;
+    GTimeVal tv;
+    gchar *t;
+    
+    g_assert(s);
+    g_assert(record);
+
+    flx_elapse_time(&tv, immediately ? 0 : FLX_RESPONSE_DEFER_MSEC, immediately ? 0 : FLX_RESPONSE_JITTER_MSEC);
+    
+    /* Don't send out duplicates */
+    
+    if ((rj = look_for_response(s, record))) {
+        glong d;
+
+        d = flx_timeval_diff(&tv, &rj->delivery);
+        
+        /* If there's already a matching packet in our history or in
+         * the schedule, we do nothing. */
+        if (!!record->ttl == !!rj->record->ttl &&
+            d >= 0 && d <= FLX_RESPONSE_HISTORY_MSEC*1000) {
+            g_message("WARNING! DUPLICATE RESPONSE SUPPRESSION ACTIVE!");
+            return;
+        }
+
+        /* Either one was a goodbye packet, but the other was not, so
+         * let's drop the older one. */
+        response_job_free(s, rj);
+    }
+
+    g_message("ACCEPTED NEW RESPONSE [%s]", t = flx_record_to_string(record));
+    g_free(t);
+
+    /* Create a new job and schedule it */
+    rj = response_job_new(s, record);
+    rj->delivery = tv;
+    rj->time_event = flx_time_event_queue_add(s->server->time_event_queue, &rj->delivery, response_elapse, rj);
 }
 
-void flx_packet_scheduler_drop_query(flxPacketScheduler *s, flxKey *key) {
+void flx_packet_scheduler_incoming_query(flxPacketScheduler *s, flxKey *key) {
+    GTimeVal tv;
     flxQueryJob *qj;
     
     g_assert(s);
     g_assert(key);
 
+    /* This function is called whenever an incoming query was
+     * receieved. We drop all scheduled queries which match here. The
+     * keyword is "DUPLICATE QUESTION SUPPRESION". */
+
     for (qj = s->query_jobs; qj; qj = qj->jobs_next)
         if (flx_key_equal(qj->key, key)) {
 
-            if (!qj->done) {
-                GTimeVal tv;
-                qj->done = TRUE;
-                
-                /* Drop query after 100ms from history */
-                flx_elapse_time(&tv, 100, 0);
-                flx_time_event_queue_update(s->server->time_event_queue, qj->time_event, &tv);
-            }
+            if (qj->done)
+                return;
 
-            break;
+            goto mark_done;
         }
+
+
+    /* No matching job was found. Add the query to the history */
+    qj = query_job_new(s, key);
+
+mark_done:
+    qj->done = TRUE;
+
+    /* Drop the query after some time */
+    flx_elapse_time(&tv, FLX_QUERY_HISTORY_MSEC, 0);
+    qj->time_event = flx_time_event_queue_add(s->server->time_event_queue, &tv, query_elapse, qj);
+
+    g_get_current_time(&qj->delivery);
+}
+
+void response_job_set_elapse_time(flxPacketScheduler *s, flxResponseJob *rj, guint msec, guint jitter) {
+    GTimeVal tv;
+
+    g_assert(s);
+    g_assert(rj);
+
+    flx_elapse_time(&tv, msec, jitter);
+
+    if (rj->time_event)
+        flx_time_event_queue_update(s->server->time_event_queue, rj->time_event, &tv);
+    else
+        rj->time_event = flx_time_event_queue_add(s->server->time_event_queue, &tv, response_elapse, rj);
+    
 }
 
-void flx_packet_scheduler_drop_response(flxPacketScheduler *s, flxRecord *record) {
+void flx_packet_scheduler_incoming_response(flxPacketScheduler *s, flxRecord *record) {
     flxResponseJob *rj;
     
     g_assert(s);
     g_assert(record);
 
-    for  (rj = s->response_jobs; rj; rj = rj->jobs_next)
+    /* This function is called whenever an incoming response was
+     * receieved. We drop all scheduled responses which match
+     * here. The keyword is "DUPLICATE ANSWER SUPPRESION". */
+    
+    for (rj = s->response_jobs; rj; rj = rj->jobs_next)
         if (flx_record_equal_no_ttl(rj->record, record)) {
 
-            if (!rj->done) {
-                GTimeVal tv;
-                rj->done = TRUE;
-                
-                /* Drop response after 100ms from history */
-                flx_elapse_time(&tv, 100, 0);
-                flx_time_event_queue_update(s->server->time_event_queue, rj->time_event, &tv);
+            if (rj->done) {
+
+                if (!!record->ttl == !!rj->record->ttl) {
+                    /* An entry like this is already in our history,
+                     * so let's get out of here! */
+                    
+                    return;
+                    
+                } else {
+                    /* Either one was a goodbye packet but other was
+                     * none. We remove the history entry, and add a
+                     * new one */
+                    
+                    response_job_free(s, rj);
+                    break;
+                }
+        
+            } else {
+
+                if (!!record->ttl == !!rj->record->ttl) {
+
+                    /* The incoming packet matches our scheduled
+                     * record, so let's mark that one as done */
+
+                    goto mark_done;
+                    
+                } else {
+
+                    /* Either one was a goodbye packet but other was
+                     * none. We ignore the incoming packet. */
+
+                    return;
+                }
             }
-
-            break;
         }
+
+    /* No matching job was found. Add the query to the history */
+    rj = response_job_new(s, record);
+
+mark_done:
+    rj->done = TRUE;
+                    
+    /* Drop response after 500ms from history */
+    response_job_set_elapse_time(s, rj, FLX_RESPONSE_HISTORY_MSEC, 0);
+
+    g_get_current_time(&rj->delivery);
+}
+
+void flx_packet_scheduler_flush_responses(flxPacketScheduler *s) {
+    flxResponseJob *rj;
+    
+    g_assert(s);
+
+    /* Send all scheduled responses, ignoring the scheduled time */
+    
+    for (rj = s->response_jobs; rj; rj = rj->jobs_next)
+        if (!rj->done)
+            send_response_packet(s, rj);
 }