Documentation update
[l2tpns.git] / cluster.c
index 7c14160..14b994a 100644 (file)
--- a/cluster.c
+++ b/cluster.c
@@ -1,6 +1,6 @@
 // L2TPNS Clustering Stuff
 
-char const *cvs_id_cluster = "$Id: cluster.c,v 1.4 2004/06/28 02:43:13 fred_nerk Exp $";
+char const *cvs_id_cluster = "$Id: cluster.c,v 1.9 2004/07/11 07:57:35 bodea Exp $";
 
 #include <stdio.h>
 #include <sys/file.h>
@@ -44,8 +44,6 @@ ipt my_address = 0;           // The network address of my ethernet port.
 static int walk_session_number = 0;    // The next session to send when doing the slow table walk.
 static int walk_tunnel_number = 0;     // The next tunnel to send when doing the slow table walk.
 
-static int hsess, fsess;       // Saved copies of the highest used session id, and the first free one.
-
 #define MAX_HEART_SIZE (8192)  // Maximum size of heartbeat packet. Must be less than max IP packet size :)
 #define MAX_CHANGES  (MAX_HEART_SIZE/(sizeof(sessiont) + sizeof(int) ) - 2)    // Assumes a session is the biggest type!
 
@@ -68,7 +66,6 @@ static struct {
        int     uptodate;
 } peers[CLUSTER_MAX_SIZE];     // List of all the peers we've heard from.
 static int num_peers;          // Number of peers in list.
-static int have_peers;         // At least one peer
 
 int rle_decompress(u8 ** src_p, int ssize, u8 *dst, int dsize);
 int rle_compress(u8 ** src_p, int ssize, u8 *dst, int dsize);
@@ -94,7 +91,7 @@ int cluster_init()
     if (!*config->cluster_interface)
        return 0;
 
-    cluster_sockfd = socket(AF_INET, SOCK_DGRAM, UDP);
+    cluster_sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 
     memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
@@ -158,8 +155,6 @@ int cluster_send_data(void *data, int datalen)
     addr.sin_port = htons(CLUSTERPORT);
     addr.sin_family = AF_INET;
 
-//    log_hex(4, "Cluster send", data, datalen); // VERY big data packets. How about we don't..
-
     log(5,0,0,0, "Cluster send data: %d bytes\n", datalen);
 
     if (sendto(cluster_sockfd, data, datalen, MSG_NOSIGNAL, (void *) &addr, sizeof(addr)) < 0)
@@ -202,18 +197,13 @@ void cluster_uptodate(void)
 
        log(0,0,0,0, "Now uptodate with master.\n");
 
-               // If we're not a master, or if we have no slaves
-               // then start taking traffic..
-       if (!config->cluster_iam_master || !have_peers)
-       {
 #ifdef BGP
-               if (bgp_configured)
-                       bgp_enable_routing(1);
-               else
+       if (bgp_configured)
+               bgp_enable_routing(1);
+       else
 #endif /* BGP */
-                       if (config->send_garp)
-                               send_garp(config->bind_address);        // Start taking traffic.
-       }
+               if (config->send_garp)
+                       send_garp(config->bind_address);        // Start taking traffic.
 }
 
 //
@@ -343,6 +333,7 @@ static void send_heartbeat(int seq, char * data, int size)
     if (size > sizeof(past_hearts[0].data)) {
        log(0,0,0,0, "Tried to heartbeat something larger than the maximum packet!\n");
        kill(0, SIGTERM);
+       exit(1);
     }
     i = seq % HB_HISTORY_SIZE;
     past_hearts[i].seq = seq;
@@ -427,6 +418,48 @@ void master_update_counts(void)
        return;
 }
 
+//
+// On the master, check how our slaves are going. If
+// one of them's not up-to-date we'll heartbeat faster.
+// If we don't have any of them, then we need to turn
+// on our own packet handling!
+//
+void cluster_check_slaves(void)
+{
+       int i;
+       static int have_peers = 0;
+       int had_peers = have_peers;
+       clockt t = TIME;
+
+       if (!config->cluster_iam_master)
+               return;         // Only runs on the master...
+
+       config->cluster_iam_uptodate = 1;       // cleared in loop below
+
+       for (i = have_peers = 0; i < num_peers; i++)
+       {
+               if ((peers[i].timestamp + config->cluster_hb_timeout) < t)
+                       continue;       // Stale peer! Skip them.
+
+               if (!peers[i].basetime)
+                       continue;       // Shutdown peer! Skip them.
+
+               if (peers[i].uptodate)
+                       have_peers = 1;
+
+               if (!peers[i].uptodate)
+                       config->cluster_iam_uptodate = 0; // Start fast heartbeats
+       }
+
+#ifdef BGP
+       // master lost all slaves, need to handle traffic ourself
+       if (bgp_configured && had_peers && !have_peers)
+               bgp_enable_routing(1);
+       else if (bgp_configured && !had_peers && have_peers)
+               bgp_enable_routing(0);
+#endif /* BGP */
+}
+
 //
 // Check that we have a master. If it's been too
 // long since we heard from a master then hold an election.
@@ -435,25 +468,47 @@ void cluster_check_master(void)
 {
        int i, count, tcount, high_sid = 0;
        int last_free = 0;
-       int had_peers = have_peers;
        clockt t = TIME;
+       static int probed = 0;
 
-       if (TIME < (config->cluster_last_hb + config->cluster_hb_timeout) )
-               return;         // Everything's ok. return.
+       if (config->cluster_iam_master)
+               return;         // Only runs on the slaves...
 
-       if (!config->cluster_iam_master)
-               log(0,0,0,0, "Master timed out! Holding election...\n");
+               // If the master is late (missed 2 hearbeats by a second and a
+               // hair) it may be that the switch has dropped us from the
+               // multicast group, try unicasting one probe to the master
+               // which will hopefully respond with a unicast heartbeat that
+               // will allow us to limp along until the querier next runs.
+       if (TIME > (config->cluster_last_hb + 2 * config->cluster_hb_interval + 11))
+       {
+               if (!probed && config->cluster_master_address)
+               {
+                       probed = 1;
+                       log(1, 0, 0, 0, "Heartbeat from master %.1fs late, probing...\n",
+                           0.1 * (TIME - (config->cluster_last_hb + config->cluster_hb_interval)));
+
+                       peer_send_message(config->cluster_master_address,
+                           C_LASTSEEN, config->cluster_seq_number, NULL, 0);
+               }
+       } else {        // We got a recent heartbeat; reset the probe flag.
+               probed = 0;
+       }
 
-       config->cluster_last_hb = TIME + 1;
+       if (TIME < (config->cluster_last_hb + config->cluster_hb_timeout))
+               return; // Everything's ok!
 
-       for (i = have_peers = 0; i < num_peers ; ++i) {
+       config->cluster_last_hb = TIME + 1;     // Just the one election thanks.
+
+       log(0,0,0,0, "Master timed out! Holding election...\n");
+
+       for (i = 0; i < num_peers; i++)
+       {
                if ((peers[i].timestamp + config->cluster_hb_timeout) < t)
                        continue;       // Stale peer! Skip them.
 
                if (!peers[i].basetime)
                        continue;       // Shutdown peer! Skip them.
 
-               have_peers = 1;
                if (peers[i].basetime < basetime) {
                        log(1,0,0,0, "Expecting %s to become master\n", inet_toa(peers[i].peer) );
                        return;         // They'll win the election. Get out of here.
@@ -466,16 +521,6 @@ void cluster_check_master(void)
                }
        }
 
-       if (config->cluster_iam_master)         // If we're the master, we've already won
-       {
-#ifdef BGP
-               // master lost all slaves, need to handle traffic ourself
-               if (bgp_configured && had_peers && !have_peers)
-                       bgp_enable_routing(1);
-#endif /* BGP */
-               return;
-       }
-
                // Wow. it's been ages since I last heard a heartbeat
                // and I'm better than an of my peers so it's time
                // to become a master!!!
@@ -485,11 +530,6 @@ void cluster_check_master(void)
 
        log(0,0,0,0, "I am declaring myself the master!\n");
 
-#ifdef BGP
-       if (bgp_configured && have_peers)
-               bgp_enable_routing(0); /* stop handling traffic */
-#endif /* BGP */
-
        if (config->cluster_seq_number == -1)
                config->cluster_seq_number = 0;
 
@@ -571,12 +611,11 @@ void cluster_check_master(void)
 
        config->cluster_undefined_sessions = 0;
        config->cluster_undefined_tunnels = 0;
+       config->cluster_iam_uptodate = 1; // assume all peers are up-to-date
 
-               //
-               // FIXME. We need to fix up the tunnel control message
-               // queue here! There's a number of other variables we
-               // should also update.
-       cluster_uptodate();
+       // FIXME. We need to fix up the tunnel control message
+       // queue here! There's a number of other variables we
+       // should also update.
 }
 
 
@@ -684,6 +723,7 @@ int hb_add_type(char **p, int type, int id)
                default:
                        log(0,0,0,0, "Found an invalid type in heart queue! (%d)\n", type);
                        kill(0, SIGTERM);
+                       exit(1);
        }
        return 0;
 }
@@ -691,31 +731,33 @@ int hb_add_type(char **p, int type, int id)
 //
 // Send a heartbeat, incidently sending out any queued changes..
 //
-void cluster_heartbeat(int highsession, int freesession, int hightunnel)
+void cluster_heartbeat()
 {
        int i, count = 0, tcount = 0;
        char buff[MAX_HEART_SIZE + sizeof(heartt) + sizeof(int) ];
        heartt h;
-       char * p = buff;
+       char *p = buff;
 
        if (!config->cluster_iam_master)        // Only the master does this.
                return;
 
-       hsess = highsession;
-       fsess = freesession;
-               // Fill out the heartbeat header.
+       // Fill out the heartbeat header.
+       memset(&h, 0, sizeof(h));
+
        h.version = HB_VERSION;
        h.seq = config->cluster_seq_number;
        h.basetime = basetime;
        h.clusterid = config->bind_address;     // Will this do??
        h.basetime = basetime;
-       h.highsession = highsession;
-       h.freesession = freesession;
-       h.hightunnel = hightunnel;
+       h.highsession = config->cluster_highest_sessionid;
+       h.freesession = sessionfree;
+       h.hightunnel = config->cluster_highest_tunnelid;
        h.size_sess = sizeof(sessiont);         // Just in case.
        h.size_tunn = sizeof(tunnelt);
+       h.interval = config->cluster_hb_interval;
+       h.timeout  = config->cluster_hb_timeout;
 
-       add_type(&p, C_HEARTBEAT, HB_VERSION, (char*) &h, sizeof(h) );
+       add_type(&p, C_HEARTBEAT, HB_VERSION, (char*) &h, sizeof(h));
 
        for (i = 0; i < config->cluster_num_changes; ++i) {
                hb_add_type(&p, cluster_changes[i].type, cluster_changes[i].id);
@@ -724,6 +766,7 @@ void cluster_heartbeat(int highsession, int freesession, int hightunnel)
        if (p > (buff + sizeof(buff))) {        // Did we somehow manage to overun the buffer?
                log(0,0,0,0, "FATAL: Overran the heartbeat buffer! This is fatal. Exiting. (size %d)\n", p - buff);
                kill(0, SIGTERM);
+               exit(1);
        }
 
                //
@@ -734,11 +777,11 @@ void cluster_heartbeat(int highsession, int freesession, int hightunnel)
                if (!walk_session_number)       // session #0 isn't valid.
                        ++walk_session_number;
 
-               if (count >= highsession)       // If we're a small cluster, don't go wild.
+               if (count >= config->cluster_highest_sessionid) // If we're a small cluster, don't go wild.
                        break;
 
                hb_add_type(&p, C_CSESSION, walk_session_number);
-               walk_session_number = (1+walk_session_number)%(highsession+1);  // +1 avoids divide by zero.
+               walk_session_number = (1+walk_session_number)%(config->cluster_highest_sessionid+1);    // +1 avoids divide by zero.
 
                ++count;                        // Count the number of extra sessions we're sending.
        }
@@ -768,10 +811,11 @@ void cluster_heartbeat(int highsession, int freesession, int hightunnel)
        if (p > (buff + sizeof(buff))) {        // Did we somehow manage to overun the buffer?
                log(0,0,0,0, "Overran the heartbeat buffer now! This is fatal. Exiting. (size %d)\n", p - buff);
                kill(0, SIGTERM);
+               exit(1);
        }
 
-       log(3,0,0,0, "Sending heartbeat with %d changes (%d x-sess, %d x-tunnels, %d highsess, %d hightun size %d)\n",
-                       config->cluster_num_changes, count, tcount, config->cluster_highest_sessionid,
+       log(3,0,0,0, "Sending heartbeat #%d with %d changes (%d x-sess, %d x-tunnels, %d highsess, %d hightun size %d)\n",
+                       h.seq, config->cluster_num_changes, count, tcount, config->cluster_highest_sessionid,
                        config->cluster_highest_tunnelid, (p-buff));
 
        config->cluster_num_changes = 0;
@@ -798,7 +842,7 @@ int type_changed(int type, int id)
        ++config->cluster_num_changes;
 
        if (config->cluster_num_changes > MAX_CHANGES)
-               cluster_heartbeat(config->cluster_highest_sessionid, fsess, config->cluster_highest_tunnelid);
+               cluster_heartbeat(); // flush now
 
        return 1;
 }
@@ -867,12 +911,25 @@ int cluster_catchup_slave(int seq, u32 slave)
 // We've heard from another peer! Add it to the list
 // that we select from at election time.
 //
-int cluster_add_peer(u32 peer, time_t basetime, pingt *p)
+int cluster_add_peer(u32 peer, time_t basetime, pingt *pp, int size)
 {
        int i;
        u32 clusterid;
+       pingt p;
+       
+
+               // Allow for backward compatability.
+               // Just the ping packet into a new structure to allow
+               // for the possibility that we might have received
+               // more or fewer elements than we were expecting.
+       if (size > sizeof(p))
+               size = sizeof(p);
+
+       memset( (void*) &p, 0, sizeof(p) );
+       memcpy( (void*) &p, (void*) pp, size);
+       
 
-       clusterid = p->addr;
+       clusterid = p.addr;
        if (clusterid != config->bind_address)
        {
                // Is this for us?
@@ -880,14 +937,6 @@ int cluster_add_peer(u32 peer, time_t basetime, pingt *p)
                return 0;
        }
 
-               // Is this the master shutting down??
-       if (peer == config->cluster_master_address && !basetime) {
-               config->cluster_master_address = 0;
-               config->cluster_last_hb = 0; // Force an election.
-               cluster_check_master();
-               return 0;
-       }
-
        for (i = 0; i < num_peers ; ++i)
        {
                if (peers[i].peer != peer)
@@ -896,9 +945,19 @@ int cluster_add_peer(u32 peer, time_t basetime, pingt *p)
                // This peer already exists. Just update the timestamp.
                peers[i].basetime = basetime;
                peers[i].timestamp = TIME;
+               peers[i].uptodate = !p.undef;
                break;
        }
 
+               // Is this the master shutting down??
+       if (peer == config->cluster_master_address && !basetime) {
+               log(3,0,0,0, "Master %s shutting down...\n", inet_toa(config->cluster_master_address));
+               config->cluster_master_address = 0;
+               config->cluster_last_hb = 0; // Force an election.
+               cluster_check_master();
+               return 0;
+       }
+
        if (i >= num_peers)
        {
                log(4,0,0,0, "Adding %s as a peer\n", inet_toa(peer));
@@ -906,8 +965,9 @@ int cluster_add_peer(u32 peer, time_t basetime, pingt *p)
                // Not found. Is there a stale slot to re-use?
                for (i = 0; i < num_peers ; ++i)
                {
-                       if (peers[i].peer != peer)
-                               continue;
+                       if (!peers[i].basetime) // Shutdown
+                               break;
+
                        if ((peers[i].timestamp + config->cluster_hb_timeout * 10) < TIME) // Stale.
                                break;
                }
@@ -922,20 +982,13 @@ int cluster_add_peer(u32 peer, time_t basetime, pingt *p)
                peers[i].peer = peer;
                peers[i].basetime = basetime;
                peers[i].timestamp = TIME;
+               peers[i].uptodate = !p.undef;
                if (i == num_peers)
                        ++num_peers;
 
                log(1,0,0,0, "Added %s as a new peer. Now %d peers\n", inet_toa(peer), num_peers);
        }
 
-#ifdef BGP
-       /* drop routes if we've now got a peer */
-       if (bgp_configured && config->cluster_iam_master && !have_peers)
-               bgp_enable_routing(0);
-#endif /* BGP */
-
-       have_peers = 1;
-
        return 1;
 }
 
@@ -1002,6 +1055,7 @@ static int cluster_recv_session(int more , u8 * p)
 
        if (!config->cluster_iam_uptodate)
                cluster_uptodate();     // Check to see if we're up to date.
+
        return 0;
 }
 
@@ -1039,23 +1093,28 @@ static int cluster_recv_tunnel(int more, u8 *p)
 
 
 //
-// Process a version one heartbeat..
+// Process a heartbeat..
 //
-static int cluster_process_heartbeat_v2(u8 * data, int size, int more, u8 * p, u32 addr)
+static int cluster_process_heartbeat(u8 * data, int size, int more, u8 * p, u32 addr)
 {
        heartt * h;
        int s = size - (p-data);
        int i, type;
 
-       if (more != HB_VERSION) {
-               log(0,0,0,0, "Received a heartbeat version that I don't understand!\n");
+#if HB_VERSION != 3
+# error "need to update cluster_process_heartbeat()"
+#endif
+
+       // we handle version 2+
+       if (more < 2 || more > HB_VERSION) {
+               log(0,0,0,0, "Received a heartbeat version that I don't support (%d)!\n", more);
                return -1; // Ignore it??
        }
+
                // Ok. It's a heartbeat packet from a cluster master!
        if (s < sizeof(*h))
                goto shortpacket;
 
-
        h = (heartt*) p;
        p += sizeof(*h);
        s -= sizeof(*h);
@@ -1068,16 +1127,18 @@ static int cluster_process_heartbeat_v2(u8 * data, int size, int more, u8 * p, u
 
                log(0,0,0,0, "I just got a packet claiming to be from a master but _I_ am the master!\n");
                if (!h->basetime) {
-                       log(0,0,0,0, "Heartbeat from addr %s with zero basetime!\n", inet_toa(htonl(addr)) );
+                       log(0,0,0,0, "Heartbeat from addr %s with zero basetime!\n", inet_toa(addr) );
                        return -1; // Skip it.
                }
                if (basetime > h->basetime) {
-                       log(0,0,0,0, "They're (%s) an older master than me so I'm gone!\n", inet_toa(htonl(addr)));
+                       log(0,0,0,0, "They're (%s) an older master than me so I'm gone!\n", inet_toa(addr));
                        kill(0, SIGTERM);
+                       exit(1);
                }
                if (basetime == h->basetime && my_address < addr) { // Tie breaker.
                        log(0,0,0,0, "They're a higher IP address than me, so I'm gone!\n");
                        kill(0, SIGTERM);
+                       exit(1);
                }
                return -1; // Skip it.
        }
@@ -1111,6 +1172,25 @@ static int cluster_process_heartbeat_v2(u8 * data, int size, int more, u8 * p, u
                        // that the free session pointer is correct.
        cluster_check_sessions(h->highsession, h->freesession, h->hightunnel);
 
+       if (more > 2) // reserved section of heartt was not initialized prior to v3
+       {
+               if (h->interval != config->cluster_hb_interval)
+               {
+                       log(2, 0, 0, 0, "Master set ping/heartbeat interval to %u (was %u)\n",
+                           h->interval, config->cluster_hb_interval);
+
+                       config->cluster_hb_interval = h->interval;
+               }
+
+               if (h->timeout != config->cluster_hb_timeout)
+               {
+                       log(2, 0, 0, 0, "Master set heartbeat timeout to %u (was %u)\n",
+                           h->timeout, config->cluster_hb_timeout);
+
+                       config->cluster_hb_timeout = h->timeout;
+               }
+       }
+
                // Ok. process the packet...
        while ( s > 0) {
 
@@ -1230,7 +1310,7 @@ int processcluster(char * data, int size, u32 addr)
 
        switch (type) {
        case C_PING:    // Update the peers table.
-               return cluster_add_peer(addr, more, (pingt*)p);
+               return cluster_add_peer(addr, more, (pingt*)p, s);
 
        case C_LASTSEEN:        // Catch up a slave (slave missed a packet).
                return cluster_catchup_slave(more, addr);
@@ -1298,14 +1378,14 @@ int processcluster(char * data, int size, u32 addr)
 
        case C_HEARTBEAT:
                log(4,0,0,0, "Got a heartbeat from %s\n", inet_toa(addr));
-
-               return cluster_process_heartbeat_v2(data, size, more, p, addr);
+               return cluster_process_heartbeat(data, size, more, p, addr);
 
        default:
                log(0,0,0,0, "Strange type packet received on cluster socket (%d)\n", type);
                return -1;
        }
        return 0;
+
 shortpacket:
        log(0,0,0,0, "I got an cluster heartbeat packet! This means I'm probably out of sync!!\n");
        return -1;