* split packet scheduler into three seperate parts

* test against Aplle test suit, most tests pass now
* suppress auxiliary records by known answers
* handle very large records


git-svn-id: file:///home/lennart/svn/public/avahi/trunk@74 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 273 insertions, 0 deletions

diff --git a/avahi-core/probe-sched.c b/avahi-core/probe-sched.c
new file mode 100644
index 0000000..9cea3e0
--- /dev/null
+++ b/avahi-core/probe-sched.c
@@ -0,0 +1,273 @@
+/* $Id$ */
+
+/***
+  This file is part of avahi.
+ 
+  avahi is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+ 
+  avahi is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
+  Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "probe-sched.h"
+#include "util.h"
+
+#define AVAHI_PROBE_DEFER_MSEC 70
+
+typedef struct AvahiProbeJob AvahiProbeJob;
+
+struct AvahiProbeJob {
+    AvahiProbeScheduler *scheduler;
+    AvahiTimeEvent *time_event;
+    
+    gboolean chosen; /* Use for packet assembling */
+    GTimeVal delivery;
+
+    AvahiRecord *record;
+    
+    AVAHI_LLIST_FIELDS(AvahiProbeJob, jobs);
+};
+
+struct AvahiProbeScheduler {
+    AvahiInterface *interface;
+    AvahiTimeEventQueue *time_event_queue;
+
+    AVAHI_LLIST_HEAD(AvahiProbeJob, jobs);
+};
+
+static AvahiProbeJob* job_new(AvahiProbeScheduler *s, AvahiRecord *record) {
+    AvahiProbeJob *pj;
+    
+    g_assert(s);
+    g_assert(record);
+
+    pj = g_new(AvahiProbeJob, 1);
+    pj->scheduler = s;
+    pj->record = avahi_record_ref(record);
+    pj->time_event = NULL;
+    pj->chosen = FALSE;
+    
+    AVAHI_LLIST_PREPEND(AvahiProbeJob, jobs, s->jobs, pj);
+
+    return pj;
+}
+
+static void job_free(AvahiProbeScheduler *s, AvahiProbeJob *pj) {
+    g_assert(pj);
+
+    if (pj->time_event)
+        avahi_time_event_queue_remove(s->time_event_queue, pj->time_event);
+
+    AVAHI_LLIST_REMOVE(AvahiProbeJob, jobs, s->jobs, pj);
+
+    avahi_record_unref(pj->record);
+    g_free(pj);
+}
+
+
+AvahiProbeScheduler *avahi_probe_scheduler_new(AvahiInterface *i) {
+    AvahiProbeScheduler *s;
+
+    g_assert(i);
+
+    s = g_new(AvahiProbeScheduler, 1);
+    s->interface = i;
+    s->time_event_queue = i->monitor->server->time_event_queue;
+
+    AVAHI_LLIST_HEAD_INIT(AvahiProbeJob, s->jobs);
+    
+    return s;
+}
+
+void avahi_probe_scheduler_free(AvahiProbeScheduler *s) {
+    g_assert(s);
+
+    avahi_probe_scheduler_clear(s);
+    g_free(s);
+}
+
+void avahi_probe_scheduler_clear(AvahiProbeScheduler *s) {
+    g_assert(s);
+    
+    while (s->jobs)
+        job_free(s, s->jobs);
+}
+ 
+static gboolean packet_add_probe_query(AvahiProbeScheduler *s, AvahiDnsPacket *p, AvahiProbeJob *pj) {
+    guint size;
+    AvahiKey *k;
+    gboolean b;
+
+    g_assert(s);
+    g_assert(p);
+    g_assert(pj);
+
+    g_assert(!pj->chosen);
+    
+    /* Estimate the size for this record */
+    size =
+        avahi_key_get_estimate_size(pj->record->key) +
+        avahi_record_get_estimate_size(pj->record);
+
+    /* Too large */
+    if (size > avahi_dns_packet_space(p))
+        return FALSE;
+
+    /* Create the probe query */
+    k = avahi_key_new(pj->record->key->name, pj->record->key->class, AVAHI_DNS_TYPE_ANY);
+    b = !!avahi_dns_packet_append_key(p, k, FALSE);
+    g_assert(b);
+
+    /* Mark this job for addition to the packet */
+    pj->chosen = TRUE;
+
+    /* Scan for more jobs whith matching key pattern */
+    for (pj = s->jobs; pj; pj = pj->jobs_next) {
+        if (pj->chosen)
+            continue;
+
+        /* Does the record match the probe? */
+        if (k->class != pj->record->key->class || !avahi_domain_equal(k->name, pj->record->key->name))
+            continue;
+        
+        /* This job wouldn't fit in */
+        if (avahi_record_get_estimate_size(pj->record) > avahi_dns_packet_space(p))
+            break;
+
+        /* Mark this job for addition to the packet */
+        pj->chosen = TRUE;
+    }
+
+    avahi_key_unref(k);
+            
+    return TRUE;
+}
+
+static void elapse_callback(AvahiTimeEvent *e, gpointer data) {
+    AvahiProbeJob *pj = data, *next;
+    AvahiProbeScheduler *s;
+    AvahiDnsPacket *p;
+    guint n;
+
+    g_assert(pj);
+    s = pj->scheduler;
+
+    p = avahi_dns_packet_new_query(s->interface->hardware->mtu);
+    n = 1;
+    
+    /* Add the import probe */
+    if (!packet_add_probe_query(s, p, pj)) {
+        guint size;
+        AvahiKey *k;
+        gboolean b;
+
+        avahi_dns_packet_free(p);
+
+        /* The probe didn't fit in the package, so let's allocate a larger one */
+
+        size =
+            avahi_key_get_estimate_size(pj->record->key) +
+            avahi_record_get_estimate_size(pj->record) +
+            AVAHI_DNS_PACKET_HEADER_SIZE;
+        
+        if (size > AVAHI_DNS_PACKET_MAX_SIZE)
+            size = AVAHI_DNS_PACKET_MAX_SIZE;
+        
+        p = avahi_dns_packet_new_query(size);
+
+        k = avahi_key_new(pj->record->key->name, pj->record->key->class, AVAHI_DNS_TYPE_ANY);
+        b = avahi_dns_packet_append_key(p, k, FALSE) && avahi_dns_packet_append_record(p, pj->record, FALSE, 0);
+        avahi_key_unref(k);
+
+        if (b) {
+            avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, 1);
+            avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, 1);
+            avahi_interface_send_packet(s->interface, p);
+        } else
+            g_warning("Probe record too large, cannot send");   
+        
+        avahi_dns_packet_free(p);
+        job_free(s, pj);
+
+        return;
+    }
+
+    /* Try to fill up packet with more probes, if available */
+    for (pj = s->jobs; pj; pj = pj->jobs_next) {
+
+        if (pj->chosen)
+            continue;
+        
+        if (!packet_add_probe_query(s, p, pj))
+            break;
+        
+        n++;
+    }
+
+    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n);
+
+    n = 0;
+
+    /* Now add the chosen records to the authorative section */
+    for (pj = s->jobs; pj; pj = next) {
+
+        next = pj->jobs_next;
+
+        if (!pj->chosen)
+            continue;
+
+        if (!avahi_dns_packet_append_record(p, pj->record, FALSE, 0)) {
+            g_warning("Bad probe size estimate!");
+
+            /* Unmark all following jobs */
+            for (; pj; pj = pj->jobs_next)
+                pj->chosen = FALSE;
+            
+            break;
+        }
+
+        job_free(s, pj);
+        
+        n ++;
+    }
+    
+    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, n);
+
+    /* Send it now */
+    avahi_interface_send_packet(s->interface, p);
+    avahi_dns_packet_free(p);
+}
+
+gboolean avahi_probe_scheduler_post(AvahiProbeScheduler *s, AvahiRecord *record, gboolean immediately) {
+    AvahiProbeJob *pj;
+    GTimeVal tv;
+    
+    g_assert(s);
+    g_assert(record);
+    g_assert(!avahi_key_is_pattern(record->key));
+    
+    avahi_elapse_time(&tv, immediately ? 0 : AVAHI_PROBE_DEFER_MSEC, 0);
+
+    /* Create a new job and schedule it */
+    pj = job_new(s, record);
+    pj->delivery = tv;
+    pj->time_event = avahi_time_event_queue_add(s->time_event_queue, &pj->delivery, elapse_callback, pj);
+
+    g_message("Accepted new probe job.");
+
+    return TRUE;
+}