Branching for wide-area publishing work

  


git-svn-id: file:///home/lennart/svn/public/avahi/branches/federico@1344 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 812 insertions, 0 deletions

diff --git a/trunk/avahi-core/iface.c b/trunk/avahi-core/iface.c
new file mode 100644
index 0000000..5685618
--- /dev/null
+++ b/trunk/avahi-core/iface.c
@@ -0,0 +1,812 @@
+/* $Id$ */
+
+/***
+  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 <string.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include <avahi-common/error.h>
+#include <avahi-common/malloc.h>
+#include <avahi-common/domain.h>
+
+#include "iface.h"
+#include "dns.h"
+#include "socket.h"
+#include "announce.h"
+#include "util.h"
+#include "log.h"
+#include "multicast-lookup.h"
+#include "querier.h"
+
+void avahi_interface_address_update_rrs(AvahiInterfaceAddress *a, int remove_rrs) {
+    AvahiInterfaceMonitor *m;
+
+    assert(a);
+    m = a->monitor;
+
+    if (a->interface->announcing &&
+        m->list_complete &&
+        avahi_interface_address_is_relevant(a) &&
+        !remove_rrs &&
+        m->server->config.publish_addresses &&
+        (m->server->state == AVAHI_SERVER_RUNNING ||
+        m->server->state == AVAHI_SERVER_REGISTERING)) {
+
+        /* Fill the entry group */
+        if (!a->entry_group) 
+            a->entry_group = avahi_s_entry_group_new(m->server, avahi_host_rr_entry_group_callback, NULL);
+
+        if (!a->entry_group) /* OOM */
+            return;
+        
+        if (avahi_s_entry_group_is_empty(a->entry_group)) {
+            char t[AVAHI_ADDRESS_STR_MAX];
+            avahi_address_snprint(t, sizeof(t), &a->address);
+
+            avahi_log_info("Registering new address record for %s on %s.", t, a->interface->hardware->name);
+
+            if (avahi_server_add_address(m->server, a->entry_group, a->interface->hardware->index, a->interface->protocol, 0, NULL, &a->address) < 0) {
+                avahi_log_warn(__FILE__": avahi_server_add_address() failed: %s", avahi_strerror(m->server->error));
+                avahi_s_entry_group_free(a->entry_group);
+                a->entry_group = NULL;
+                return;
+            }
+
+            avahi_s_entry_group_commit(a->entry_group);
+        }
+    } else {
+
+        /* Clear the entry group */
+
+        if (a->entry_group && !avahi_s_entry_group_is_empty(a->entry_group)) {
+            char t[AVAHI_ADDRESS_STR_MAX];
+            avahi_address_snprint(t, sizeof(t), &a->address);
+
+            if (avahi_s_entry_group_get_state(a->entry_group) == AVAHI_ENTRY_GROUP_REGISTERING &&
+		m->server->state == AVAHI_SERVER_REGISTERING)
+                avahi_server_decrease_host_rr_pending(m->server);
+
+            avahi_log_info("Withdrawing address record for %s on %s.", t, a->interface->hardware->name);
+            
+            avahi_s_entry_group_reset(a->entry_group);
+        }
+    } 
+}
+
+void avahi_interface_update_rrs(AvahiInterface *i, int remove_rrs) {
+    AvahiInterfaceAddress *a;
+    
+    assert(i);
+
+    for (a = i->addresses; a; a = a->address_next)
+        avahi_interface_address_update_rrs(a, remove_rrs);
+}
+
+void avahi_hw_interface_update_rrs(AvahiHwInterface *hw, int remove_rrs) {
+    AvahiInterface *i;
+    AvahiInterfaceMonitor *m;
+
+    assert(hw);
+    m = hw->monitor;
+
+    for (i = hw->interfaces; i; i = i->by_hardware_next)
+        avahi_interface_update_rrs(i, remove_rrs);
+
+    if (m->list_complete &&
+        !remove_rrs &&
+        m->server->config.publish_workstation &&
+        (m->server->state == AVAHI_SERVER_RUNNING)) {
+
+        if (!hw->entry_group)
+            hw->entry_group = avahi_s_entry_group_new(m->server, avahi_host_rr_entry_group_callback, NULL);
+
+        if (!hw->entry_group)
+            return; /* OOM */
+        
+        if (avahi_s_entry_group_is_empty(hw->entry_group)) {
+            char name[AVAHI_LABEL_MAX], mac[256];
+
+            avahi_format_mac_address(mac, sizeof(mac), hw->mac_address, hw->mac_address_size);
+            snprintf(name, sizeof(name), "%s [%s]", m->server->host_name, mac);
+
+            if (avahi_server_add_service(m->server, hw->entry_group, hw->index, AVAHI_PROTO_UNSPEC, 0, name, "_workstation._tcp", NULL, NULL, 9, NULL) < 0) { 
+                avahi_log_warn(__FILE__": avahi_server_add_service() failed: %s", avahi_strerror(m->server->error));
+                avahi_s_entry_group_free(hw->entry_group);
+                hw->entry_group = NULL;
+            } else
+                avahi_s_entry_group_commit(hw->entry_group);
+        }
+        
+    } else {
+
+        if (hw->entry_group && !avahi_s_entry_group_is_empty(hw->entry_group)) {
+
+            if (avahi_s_entry_group_get_state(hw->entry_group) == AVAHI_ENTRY_GROUP_REGISTERING)
+                avahi_server_decrease_host_rr_pending(m->server);
+
+            avahi_s_entry_group_reset(hw->entry_group);
+        }
+    }
+}
+
+void avahi_interface_monitor_update_rrs(AvahiInterfaceMonitor *m, int remove_rrs) {
+    AvahiHwInterface *hw;
+
+    assert(m);
+
+    for (hw = m->hw_interfaces; hw; hw = hw->hardware_next)
+        avahi_hw_interface_update_rrs(hw, remove_rrs);
+}
+
+static int interface_mdns_mcast_join(AvahiInterface *i, int join) {
+    char at[AVAHI_ADDRESS_STR_MAX];
+    int r;
+    assert(i);
+
+    if (!!join  == !!i->mcast_joined)
+        return 0;
+    
+    if (join) {
+        AvahiInterfaceAddress *a;
+
+        /* Look if there's an address with global scope */
+        for (a = i->addresses; a; a = a->address_next)
+            if (a->global_scope)
+                break;
+
+        /* No address with a global scope has been found, so let's use
+         * any. */
+        if (!a)
+            a = i->addresses;
+
+        /* Hmm, there is no address available. */
+        if (!a) {
+            avahi_log_warn(__FILE__": interface_mdns_mcast_join() called but no local address available."); 
+            return -1;
+        }
+
+        i->local_mcast_address = a->address;
+    }
+
+    avahi_log_info("%s mDNS multicast group on interface %s.%s with address %s.",
+                   join ? "Joining" : "Leaving",
+                   i->hardware->name,
+                   avahi_proto_to_string(i->protocol),
+                   avahi_address_snprint(at, sizeof(at), &i->local_mcast_address));
+
+    if (i->protocol == AVAHI_PROTO_INET6)
+        r = avahi_mdns_mcast_join_ipv6(i->monitor->server->fd_ipv6, &i->local_mcast_address.data.ipv6, i->hardware->index, join);
+    else {
+        assert(i->protocol == AVAHI_PROTO_INET);
+            
+        r = avahi_mdns_mcast_join_ipv4(i->monitor->server->fd_ipv4, &i->local_mcast_address.data.ipv4, i->hardware->index, join);
+    }
+
+    if (r < 0)
+        i->mcast_joined = 0;
+    else
+        i->mcast_joined = join;
+    
+    return 0;
+}
+
+static int interface_mdns_mcast_rejoin(AvahiInterface *i) {
+    AvahiInterfaceAddress *a, *usable = NULL, *found = NULL;
+    assert(i);
+
+    if (!i->mcast_joined)
+        return 0;
+
+    /* Check whether old address we joined with is still available. If
+     * not, rejoin using an other address. */
+    
+    for (a = i->addresses; a; a = a->address_next) {
+        if (a->global_scope && !usable)
+            usable = a;
+        
+        if (avahi_address_cmp(&a->address, &i->local_mcast_address) == 0) {
+
+            if (a->global_scope)
+                /* No action necessary: the address still exists and
+                 * has global scope. */
+                return 0;
+
+            found = a;
+        }
+    }
+
+    if (found && !usable)
+        /* No action necessary: the address still exists and no better one has been found */
+        return 0;
+    
+    interface_mdns_mcast_join(i, 0);
+    return interface_mdns_mcast_join(i, 1);
+}
+
+void avahi_interface_address_free(AvahiInterfaceAddress *a) {
+    assert(a);
+    assert(a->interface);
+
+    avahi_interface_address_update_rrs(a, 1);
+    AVAHI_LLIST_REMOVE(AvahiInterfaceAddress, address, a->interface->addresses, a);
+
+    if (a->entry_group)
+        avahi_s_entry_group_free(a->entry_group);
+
+    interface_mdns_mcast_rejoin(a->interface);
+    
+    avahi_free(a);
+}
+
+void avahi_interface_free(AvahiInterface *i, int send_goodbye) {
+    assert(i);
+
+    /* Handle goodbyes and remove announcers */
+    avahi_goodbye_interface(i->monitor->server, i, send_goodbye, 1);
+    avahi_response_scheduler_force(i->response_scheduler);
+    assert(!i->announcers);
+
+    if (i->mcast_joined)
+        interface_mdns_mcast_join(i, 0);
+    
+    /* Remove queriers */
+    avahi_querier_free_all(i);
+    avahi_hashmap_free(i->queriers_by_key);
+
+    /* Remove local RRs */
+    avahi_interface_update_rrs(i, 1);
+    
+    while (i->addresses)
+        avahi_interface_address_free(i->addresses);
+
+    avahi_response_scheduler_free(i->response_scheduler);
+    avahi_query_scheduler_free(i->query_scheduler);
+    avahi_probe_scheduler_free(i->probe_scheduler);
+    avahi_cache_free(i->cache);
+    
+    AVAHI_LLIST_REMOVE(AvahiInterface, interface, i->monitor->interfaces, i);
+    AVAHI_LLIST_REMOVE(AvahiInterface, by_hardware, i->hardware->interfaces, i);
+    
+    avahi_free(i);
+}
+
+void avahi_hw_interface_free(AvahiHwInterface *hw, int send_goodbye) {
+    assert(hw);
+
+    avahi_hw_interface_update_rrs(hw, 1);
+    
+    while (hw->interfaces)
+        avahi_interface_free(hw->interfaces, send_goodbye);
+
+    if (hw->entry_group)
+        avahi_s_entry_group_free(hw->entry_group);
+    
+    AVAHI_LLIST_REMOVE(AvahiHwInterface, hardware, hw->monitor->hw_interfaces, hw);
+    avahi_hashmap_remove(hw->monitor->hashmap, &hw->index);
+
+    avahi_free(hw->name);
+    avahi_free(hw);
+}
+
+AvahiInterface* avahi_interface_new(AvahiInterfaceMonitor *m, AvahiHwInterface *hw, AvahiProtocol protocol) {
+    AvahiInterface *i;
+    
+    assert(m);
+    assert(hw);
+    assert(AVAHI_PROTO_VALID(protocol));
+
+    if (!(i = avahi_new(AvahiInterface, 1)))
+        goto fail; /* OOM */
+        
+    i->monitor = m;
+    i->hardware = hw;
+    i->protocol = protocol;
+    i->announcing = 0;
+    i->mcast_joined = 0;
+
+    AVAHI_LLIST_HEAD_INIT(AvahiInterfaceAddress, i->addresses);
+    AVAHI_LLIST_HEAD_INIT(AvahiAnnouncer, i->announcers);
+
+    AVAHI_LLIST_HEAD_INIT(AvahiQuerier, i->queriers);
+    i->queriers_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, NULL, NULL);
+
+    i->cache = avahi_cache_new(m->server, i);
+    i->response_scheduler = avahi_response_scheduler_new(i);
+    i->query_scheduler = avahi_query_scheduler_new(i);
+    i->probe_scheduler = avahi_probe_scheduler_new(i);
+
+    if (!i->cache || !i->response_scheduler || !i->query_scheduler || !i->probe_scheduler)
+        goto fail; /* OOM */
+
+    AVAHI_LLIST_PREPEND(AvahiInterface, by_hardware, hw->interfaces, i);
+    AVAHI_LLIST_PREPEND(AvahiInterface, interface, m->interfaces, i);
+
+    return i;
+    
+fail:
+
+    if (i) {
+        if (i->cache)
+            avahi_cache_free(i->cache);
+        if (i->response_scheduler)
+            avahi_response_scheduler_free(i->response_scheduler);
+        if (i->query_scheduler)
+            avahi_query_scheduler_free(i->query_scheduler);
+        if (i->probe_scheduler)
+            avahi_probe_scheduler_free(i->probe_scheduler);
+    }
+
+    return NULL;
+}
+
+AvahiHwInterface *avahi_hw_interface_new(AvahiInterfaceMonitor *m, AvahiIfIndex idx) {
+    AvahiHwInterface *hw;
+    
+    assert(m);
+    assert(AVAHI_IF_VALID(idx));
+
+    if  (!(hw = avahi_new(AvahiHwInterface, 1)))
+        return NULL;
+        
+    hw->monitor = m;
+    hw->name = NULL;
+    hw->flags_ok = 0;
+    hw->mtu = 1500;
+    hw->index = idx;
+    hw->mac_address_size = 0;
+    hw->entry_group = NULL;
+
+    AVAHI_LLIST_HEAD_INIT(AvahiInterface, hw->interfaces);
+    AVAHI_LLIST_PREPEND(AvahiHwInterface, hardware, m->hw_interfaces, hw);
+            
+    avahi_hashmap_insert(m->hashmap, &hw->index, hw);
+
+    if (m->server->fd_ipv4 >= 0)
+        avahi_interface_new(m, hw, AVAHI_PROTO_INET);
+    if (m->server->fd_ipv6 >= 0)
+        avahi_interface_new(m, hw, AVAHI_PROTO_INET6);
+
+    return hw;
+}
+
+AvahiInterfaceAddress *avahi_interface_address_new(AvahiInterfaceMonitor *m, AvahiInterface *i, const AvahiAddress *addr, unsigned prefix_len) {
+    AvahiInterfaceAddress *a;
+
+    assert(m);
+    assert(i);
+
+    if (!(a = avahi_new(AvahiInterfaceAddress, 1)))
+        return NULL;
+
+    a->interface = i;
+    a->monitor = m;
+    a->address = *addr;
+    a->prefix_len = prefix_len;
+    a->global_scope = 0;
+    a->entry_group = NULL;
+
+    AVAHI_LLIST_PREPEND(AvahiInterfaceAddress, address, i->addresses, a);
+
+    return a;
+}
+
+void avahi_interface_check_relevant(AvahiInterface *i) {
+    int b;
+    AvahiInterfaceMonitor *m;
+
+    assert(i);
+    m = i->monitor;
+
+    b = avahi_interface_is_relevant(i);
+
+    if (m->list_complete && b && !i->announcing) {
+        avahi_log_info("New relevant interface %s.%s for mDNS.", i->hardware->name, avahi_proto_to_string(i->protocol));
+
+        interface_mdns_mcast_join(i, 1);
+
+        i->announcing = 1;
+        avahi_announce_interface(m->server, i);
+        avahi_multicast_lookup_engine_new_interface(m->server->multicast_lookup_engine, i);
+    } else if (!b && i->announcing) {
+        avahi_log_info("Interface %s.%s no longer relevant for mDNS.", i->hardware->name, avahi_proto_to_string(i->protocol));
+
+        interface_mdns_mcast_join(i, 0);
+
+        avahi_goodbye_interface(m->server, i, 0, 1);
+        avahi_querier_free_all(i);
+
+        avahi_response_scheduler_clear(i->response_scheduler);
+        avahi_query_scheduler_clear(i->query_scheduler);
+        avahi_probe_scheduler_clear(i->probe_scheduler);
+        avahi_cache_flush(i->cache);
+
+        i->announcing = 0;
+        
+    } else
+        interface_mdns_mcast_rejoin(i);
+}
+
+void avahi_hw_interface_check_relevant(AvahiHwInterface *hw) {
+    AvahiInterface *i;
+    
+    assert(hw);
+
+    for (i = hw->interfaces; i; i = i->by_hardware_next)
+        avahi_interface_check_relevant(i);
+}
+
+void avahi_interface_monitor_check_relevant(AvahiInterfaceMonitor *m) {
+    AvahiInterface *i;
+
+    assert(m);
+
+    for (i = m->interfaces; i; i = i->interface_next)
+        avahi_interface_check_relevant(i);
+}
+
+AvahiInterfaceMonitor *avahi_interface_monitor_new(AvahiServer *s) {
+    AvahiInterfaceMonitor *m = NULL;
+
+    if (!(m = avahi_new0(AvahiInterfaceMonitor, 1)))
+        return NULL; /* OOM */
+        
+    m->server = s;
+    m->list_complete = 0;
+    m->hashmap = avahi_hashmap_new(avahi_int_hash, avahi_int_equal, NULL, NULL);
+
+    AVAHI_LLIST_HEAD_INIT(AvahiInterface, m->interfaces);
+    AVAHI_LLIST_HEAD_INIT(AvahiHwInterface, m->hw_interfaces);
+
+    if (avahi_interface_monitor_init_osdep(m) < 0)
+        goto fail;
+
+    return m;
+
+fail:
+    avahi_interface_monitor_free(m);
+    return NULL;
+}
+
+void avahi_interface_monitor_free(AvahiInterfaceMonitor *m) {
+    assert(m);
+
+    while (m->hw_interfaces)
+        avahi_hw_interface_free(m->hw_interfaces, 1);
+
+    assert(!m->interfaces);
+
+    avahi_interface_monitor_free_osdep(m);
+    
+    if (m->hashmap)
+        avahi_hashmap_free(m->hashmap);
+
+    avahi_free(m);
+}
+
+
+AvahiInterface* avahi_interface_monitor_get_interface(AvahiInterfaceMonitor *m, AvahiIfIndex idx, AvahiProtocol protocol) {
+    AvahiHwInterface *hw;
+    AvahiInterface *i;
+    
+    assert(m);
+    assert(idx >= 0);
+    assert(protocol != AVAHI_PROTO_UNSPEC);
+
+    if (!(hw = avahi_interface_monitor_get_hw_interface(m, idx)))
+        return NULL;
+
+    for (i = hw->interfaces; i; i = i->by_hardware_next)
+        if (i->protocol == protocol)
+            return i;
+
+    return NULL;
+}
+
+AvahiHwInterface* avahi_interface_monitor_get_hw_interface(AvahiInterfaceMonitor *m, AvahiIfIndex idx) {
+    assert(m);
+    assert(idx > 0);
+
+    return avahi_hashmap_lookup(m->hashmap, &idx);
+}
+
+AvahiInterfaceAddress* avahi_interface_monitor_get_address(AvahiInterfaceMonitor *m, AvahiInterface *i, const AvahiAddress *raddr) {
+    AvahiInterfaceAddress *ia;
+    
+    assert(m);
+    assert(i);
+    assert(raddr);
+
+    for (ia = i->addresses; ia; ia = ia->address_next)
+        if (avahi_address_cmp(&ia->address, raddr) == 0)
+            return ia;
+
+    return NULL;
+}
+
+void avahi_interface_send_packet_unicast(AvahiInterface *i, AvahiDnsPacket *p, const AvahiAddress *a, uint16_t port) {
+    assert(i);
+    assert(p);
+
+    if (!avahi_interface_is_relevant(i))
+        return;
+    
+    assert(!a || a->proto == i->protocol);
+
+    if (i->protocol == AVAHI_PROTO_INET && i->monitor->server->fd_ipv4 >= 0)
+        avahi_send_dns_packet_ipv4(i->monitor->server->fd_ipv4, i->hardware->index, p, i->mcast_joined ? &i->local_mcast_address.data.ipv4 : NULL, a ? &a->data.ipv4 : NULL, port);
+    else if (i->protocol == AVAHI_PROTO_INET6 && i->monitor->server->fd_ipv6 >= 0)
+        avahi_send_dns_packet_ipv6(i->monitor->server->fd_ipv6, i->hardware->index, p, i->mcast_joined ? &i->local_mcast_address.data.ipv6 : NULL, a ? &a->data.ipv6 : NULL, port);
+}
+
+void avahi_interface_send_packet(AvahiInterface *i, AvahiDnsPacket *p) {
+    assert(i);
+    assert(p);
+
+    avahi_interface_send_packet_unicast(i, p, NULL, 0);
+}
+
+int avahi_interface_post_query(AvahiInterface *i, AvahiKey *key, int immediately, unsigned *ret_id) {
+    assert(i);
+    assert(key);
+
+    if (avahi_interface_is_relevant(i))
+        return avahi_query_scheduler_post(i->query_scheduler, key, immediately, ret_id);
+
+    return 0;
+}
+
+int avahi_interface_withraw_query(AvahiInterface *i, unsigned id) {
+
+    return avahi_query_scheduler_withdraw_by_id(i->query_scheduler, id);
+}
+
+int avahi_interface_post_response(AvahiInterface *i, AvahiRecord *record, int flush_cache, const AvahiAddress *querier, int immediately) {
+    assert(i);
+    assert(record);
+
+    if (avahi_interface_is_relevant(i))
+        return avahi_response_scheduler_post(i->response_scheduler, record, flush_cache, querier, immediately);
+
+    return 0;
+}
+
+int avahi_interface_post_probe(AvahiInterface *i, AvahiRecord *record, int immediately) {
+    assert(i);
+    assert(record);
+    
+    if (avahi_interface_is_relevant(i))
+        return avahi_probe_scheduler_post(i->probe_scheduler, record, immediately);
+
+    return 0;
+}
+
+int avahi_dump_caches(AvahiInterfaceMonitor *m, AvahiDumpCallback callback, void* userdata) {
+    AvahiInterface *i;
+    assert(m);
+
+    for (i = m->interfaces; i; i = i->interface_next) {
+        if (avahi_interface_is_relevant(i)) {
+            char ln[256];
+            snprintf(ln, sizeof(ln), ";;; INTERFACE %s.%s ;;;", i->hardware->name, avahi_proto_to_string(i->protocol));
+            callback(ln, userdata);
+            if (avahi_cache_dump(i->cache, callback, userdata) < 0)
+                return -1;
+        }
+    }
+
+    return 0;
+}
+
+int avahi_interface_is_relevant(AvahiInterface *i) {
+    AvahiInterfaceAddress *a;
+    int relevant_address;
+    
+    assert(i);
+
+    relevant_address = 0;
+    
+    for (a = i->addresses; a; a = a->address_next)
+        if (avahi_interface_address_is_relevant(a)) {
+            relevant_address = 1;
+            break;
+        }
+
+    return i->hardware->flags_ok && relevant_address;
+}
+
+int avahi_interface_address_is_relevant(AvahiInterfaceAddress *a) {
+    AvahiInterfaceAddress *b;
+    assert(a);
+
+    /* Publish public IP addresses */
+    if (a->global_scope)
+        return 1;
+    else {
+        
+        /* Publish link local IP addresses if they are the only ones on the link */
+        for (b = a->interface->addresses; b; b = b->address_next) {
+            if (b == a)
+                continue;
+            
+            if (b->global_scope)
+                return 0;
+        }
+
+        return 1;
+    }
+
+    return 0;
+}
+
+int avahi_interface_match(AvahiInterface *i, AvahiIfIndex idx, AvahiProtocol protocol) {
+    assert(i);
+    
+    if (idx != AVAHI_IF_UNSPEC && idx != i->hardware->index)
+        return 0;
+
+    if (protocol != AVAHI_PROTO_UNSPEC && protocol != i->protocol)
+        return 0;
+
+    return 1;
+}
+
+void avahi_interface_monitor_walk(AvahiInterfaceMonitor *m, AvahiIfIndex interface, AvahiProtocol protocol, AvahiInterfaceMonitorWalkCallback callback, void* userdata) {
+    assert(m);
+    assert(callback);
+    
+    if (interface != AVAHI_IF_UNSPEC) {
+        if (protocol != AVAHI_PROTO_UNSPEC) {
+            AvahiInterface *i;
+            
+            if ((i = avahi_interface_monitor_get_interface(m, interface, protocol)))
+                callback(m, i, userdata);
+            
+        } else {
+            AvahiHwInterface *hw;
+            AvahiInterface *i;
+
+            if ((hw = avahi_interface_monitor_get_hw_interface(m, interface)))
+                for (i = hw->interfaces; i; i = i->by_hardware_next)
+                    if (avahi_interface_match(i, interface, protocol))
+                        callback(m, i, userdata);
+        }
+        
+    } else {
+        AvahiInterface *i;
+        
+        for (i = m->interfaces; i; i = i->interface_next)
+            if (avahi_interface_match(i, interface, protocol))
+                callback(m, i, userdata);
+    }
+}
+
+
+int avahi_address_is_local(AvahiInterfaceMonitor *m, const AvahiAddress *a) {
+    AvahiInterface *i;
+    AvahiInterfaceAddress *ia;
+    assert(m);
+    assert(a);
+
+    for (i = m->interfaces; i; i = i->interface_next)
+        for (ia = i->addresses; ia; ia = ia->address_next)
+            if (avahi_address_cmp(a, &ia->address) == 0)
+                return 1;
+
+    return 0;
+}
+
+int avahi_interface_address_on_link(AvahiInterface *i, const AvahiAddress *a) {
+    AvahiInterfaceAddress *ia;
+    
+    assert(i);
+    assert(a);
+
+    if (a->proto != i->protocol)
+        return 0;
+
+    for (ia = i->addresses; ia; ia = ia->address_next) {
+
+        if (a->proto == AVAHI_PROTO_INET) {
+            uint32_t m;
+            
+            m = ~(((uint32_t) -1) >> ia->prefix_len);
+            
+            if ((ntohl(a->data.ipv4.address) & m) == (ntohl(ia->address.data.ipv4.address) & m))
+                return 1;
+        } else {
+            unsigned j;
+            unsigned char pl;
+            assert(a->proto == AVAHI_PROTO_INET6);
+
+            pl = ia->prefix_len;
+            
+            for (j = 0; j < 16; j++) {
+                uint8_t m;
+
+                if (pl == 0)
+                    return 1;
+                
+                if (pl >= 8) {
+                    m = 0xFF;
+                    pl -= 8;
+                } else {
+                    m = ~(0xFF >> pl);
+                    pl = 0;
+                }
+                
+                if ((a->data.ipv6.address[j] & m) != (ia->address.data.ipv6.address[j] & m))
+                    break;
+            }
+        }
+    }
+
+    return 0;
+}
+
+int avahi_interface_has_address(AvahiInterfaceMonitor *m, AvahiIfIndex iface, const AvahiAddress *a) {
+    AvahiInterface *i;
+    AvahiInterfaceAddress *j;
+    
+    assert(m);
+    assert(iface != AVAHI_IF_UNSPEC);
+    assert(a);
+
+    if (!(i = avahi_interface_monitor_get_interface(m, iface, a->proto)))
+        return 0;
+
+    for (j = i->addresses; j; j = j->address_next)
+        if (avahi_address_cmp(a, &j->address) == 0)
+            return 1;
+
+    return 0;
+}
+
+AvahiIfIndex avahi_find_interface_for_address(AvahiInterfaceMonitor *m, const AvahiAddress *a) {
+    AvahiInterface *i;
+    assert(m);
+
+    /* Some stupid OS don't support passing the interface index when a
+     * packet is recieved. We have to work around that limitation by
+     * looking for an interface that has the incoming address
+     * attached. This is sometimes ambiguous, but we have to live with
+     * it. */
+
+    for (i = m->interfaces; i; i = i->interface_next) {
+        AvahiInterfaceAddress *ai;
+
+        if (i->protocol != a->proto)
+            continue;
+        
+        for (ai = i->addresses; ai; ai = ai->address_next)
+            if (avahi_address_cmp(a, &ai->address) == 0)
+                return i->hardware->index;
+    }
+
+    return AVAHI_IF_UNSPEC;
+}