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authorJeremy Allison <jra@samba.org>2010-02-10 12:32:05 -0800
committerJeremy Allison <jra@samba.org>2010-02-10 12:32:05 -0800
commitc2f3ed48c5ac253bb17387800579f94d933b71e1 (patch)
tree9c540dd760b965af0fa993b60c82a5d11e37c1ce /source3
parent84fba3c1bc962804259f201d465acfdf0cd3c6a8 (diff)
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More of the fix for bug #7118 - nmbd problems with socket address.
Add a simple "processed packet queue" cache to stop nmbd responding to packets received on the broadcast and non-broadcast socket (which it has opened when "nmbd bind explicit broadcast = yes"). This is a very simple packet queue - it only keeps the packets processed during a single call to listen_for_packets() (i.e. one select call). This means that if the delivery notification for a packet received on both broadcast and non-broadcast addresses is done in two different select calls, the packet will still be processed twice. This is a very rare occurrance and we can just live with it when it does as the protocol is stateless. If this is ever flagged as a repeatable problem then we can add a longer lived cache, using timeout processing to clear etc. etc. But without storing all packets processed we can never be *sure* we've eliminated the race condition so I'm going to go with this simple solution until someone proves a more complex one is needed :-). Jeremy.
Diffstat (limited to 'source3')
-rw-r--r--source3/nmbd/nmbd_packets.c89
1 files changed, 89 insertions, 0 deletions
diff --git a/source3/nmbd/nmbd_packets.c b/source3/nmbd/nmbd_packets.c
index 55fd24dc35..a753b2841d 100644
--- a/source3/nmbd/nmbd_packets.c
+++ b/source3/nmbd/nmbd_packets.c
@@ -1765,6 +1765,83 @@ only use %d.\n", count, FD_SETSIZE));
}
/****************************************************************************
+ List of packets we're processing this select.
+***************************************************************************/
+
+struct processed_packet {
+ struct processed_packet *next;
+ struct processed_packet *prev;
+ enum packet_type packet_type;
+ struct in_addr ip;
+ int packet_id;
+};
+
+/****************************************************************************
+ Have we seen this before ?
+***************************************************************************/
+
+static bool is_processed_packet(struct processed_packet *processed_packet_list,
+ struct packet_struct *packet)
+{
+ struct processed_packet *p = NULL;
+
+ for (p = processed_packet_list; p; p = p->next) {
+ if (ip_equal_v4(p->ip, packet->ip) && p->packet_type == packet->packet_type) {
+ if ((p->packet_type == NMB_PACKET) &&
+ (p->packet_id ==
+ packet->packet.nmb.header.name_trn_id)) {
+ return true;
+ } else if ((p->packet_type == DGRAM_PACKET) &&
+ (p->packet_id ==
+ packet->packet.dgram.header.dgm_id)) {
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+/****************************************************************************
+ Keep a list of what we've seen before.
+***************************************************************************/
+
+static bool store_processed_packet(struct processed_packet **pp_processed_packet_list,
+ struct packet_struct *packet)
+{
+ struct processed_packet *p = SMB_MALLOC_P(struct processed_packet);
+ if (!p) {
+ return false;
+ }
+ p->packet_type = packet->packet_type;
+ p->ip = packet->ip;
+ if (packet->packet_type == NMB_PACKET) {
+ p->packet_id = packet->packet.nmb.header.name_trn_id;
+ } else if (packet->packet_type == DGRAM_PACKET) {
+ p->packet_id = packet->packet.dgram.header.dgm_id;
+ } else {
+ return false;
+ }
+
+ DLIST_ADD(*pp_processed_packet_list, p);
+ return true;
+}
+
+/****************************************************************************
+ Throw away what we've seen before.
+***************************************************************************/
+
+static void free_processed_packet_list(struct processed_packet **pp_processed_packet_list)
+{
+ struct processed_packet *p = NULL, *next = NULL;
+
+ for (p = *pp_processed_packet_list; p; p = next) {
+ next = p->next;
+ DLIST_REMOVE(*pp_processed_packet_list, p);
+ SAFE_FREE(p);
+ }
+}
+
+/****************************************************************************
Listens for NMB or DGRAM packets, and queues them.
return True if the socket is dead
***************************************************************************/
@@ -1784,6 +1861,7 @@ bool listen_for_packets(bool run_election)
#ifndef SYNC_DNS
int dns_fd;
#endif
+ struct processed_packet *processed_packet_list = NULL;
if(listen_set == NULL || rescan_listen_set) {
if(create_listen_fdset(&listen_set, &sock_array, &listen_number, &maxfd)) {
@@ -1906,6 +1984,16 @@ bool listen_for_packets(bool run_election)
}
}
+
+ if (is_processed_packet(processed_packet_list, packet)) {
+ DEBUG(7,("discarding duplicate packet from %s:%d\n",
+ inet_ntoa(packet->ip),packet->port));
+ free_packet(packet);
+ continue;
+ }
+
+ store_processed_packet(&processed_packet_list, packet);
+
/*
* 0,2,4,... are unicast sockets
* 1,3,5,... are broadcast sockets
@@ -1926,6 +2014,7 @@ bool listen_for_packets(bool run_election)
queue_packet(packet);
}
+ free_processed_packet_list(&processed_packet_list);
return False;
}