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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.
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@ -1764,6 +1764,83 @@ only use %d.\n", count, FD_SETSIZE));
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return False;
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}
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/****************************************************************************
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List of packets we're processing this select.
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***************************************************************************/
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struct processed_packet {
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struct processed_packet *next;
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struct processed_packet *prev;
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enum packet_type packet_type;
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struct in_addr ip;
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int packet_id;
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};
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/****************************************************************************
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Have we seen this before ?
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***************************************************************************/
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static bool is_processed_packet(struct processed_packet *processed_packet_list,
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struct packet_struct *packet)
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{
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struct processed_packet *p = NULL;
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for (p = processed_packet_list; p; p = p->next) {
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if (ip_equal_v4(p->ip, packet->ip) && p->packet_type == packet->packet_type) {
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if ((p->packet_type == NMB_PACKET) &&
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(p->packet_id ==
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packet->packet.nmb.header.name_trn_id)) {
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return true;
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} else if ((p->packet_type == DGRAM_PACKET) &&
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(p->packet_id ==
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packet->packet.dgram.header.dgm_id)) {
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return true;
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}
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}
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}
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return false;
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}
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/****************************************************************************
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Keep a list of what we've seen before.
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***************************************************************************/
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static bool store_processed_packet(struct processed_packet **pp_processed_packet_list,
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struct packet_struct *packet)
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{
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struct processed_packet *p = SMB_MALLOC_P(struct processed_packet);
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if (!p) {
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return false;
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}
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p->packet_type = packet->packet_type;
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p->ip = packet->ip;
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if (packet->packet_type == NMB_PACKET) {
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p->packet_id = packet->packet.nmb.header.name_trn_id;
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} else if (packet->packet_type == DGRAM_PACKET) {
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p->packet_id = packet->packet.dgram.header.dgm_id;
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} else {
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return false;
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}
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DLIST_ADD(*pp_processed_packet_list, p);
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return true;
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}
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/****************************************************************************
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Throw away what we've seen before.
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***************************************************************************/
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static void free_processed_packet_list(struct processed_packet **pp_processed_packet_list)
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{
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struct processed_packet *p = NULL, *next = NULL;
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for (p = *pp_processed_packet_list; p; p = next) {
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next = p->next;
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DLIST_REMOVE(*pp_processed_packet_list, p);
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SAFE_FREE(p);
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}
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}
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/****************************************************************************
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Listens for NMB or DGRAM packets, and queues them.
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return True if the socket is dead
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@ -1784,6 +1861,7 @@ bool listen_for_packets(bool run_election)
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#ifndef SYNC_DNS
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int dns_fd;
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#endif
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struct processed_packet *processed_packet_list = NULL;
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if(listen_set == NULL || rescan_listen_set) {
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if(create_listen_fdset(&listen_set, &sock_array, &listen_number, &maxfd)) {
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@ -1906,6 +1984,16 @@ bool listen_for_packets(bool run_election)
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}
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}
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if (is_processed_packet(processed_packet_list, packet)) {
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DEBUG(7,("discarding duplicate packet from %s:%d\n",
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inet_ntoa(packet->ip),packet->port));
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free_packet(packet);
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continue;
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}
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store_processed_packet(&processed_packet_list, packet);
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/*
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* 0,2,4,... are unicast sockets
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* 1,3,5,... are broadcast sockets
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@ -1926,6 +2014,7 @@ bool listen_for_packets(bool run_election)
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queue_packet(packet);
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}
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free_processed_packet_list(&processed_packet_list);
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return False;
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}
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