viced-host-nat-20060207

When we discover a new address for an existing host we can take the
opportunity to cleanup the hash table and the interface list if the
new address differs from an existing address only by the port number.
In that case we know the client is communicating to us from behind a
NAT and the old addr/port number combination is no longer going to
be of use to us.

diff --git a/src/viced/host.c b/src/viced/host.c
index d3fe54fc52b148e63fac963296dec2748ed565c2..550ae9762017e997153d15e7117a154f01aaa751 100644 (file)
--- a/src/viced/host.c
+++ b/src/viced/host.c
@@ -1011,6 +1011,61 @@ addInterfaceAddr_r(struct host *host, afs_uint32 addr, afs_uint16 port)
 }
 
 
+/*
+ * This is called with host locked and held. At this point, the
+ * hostHashTable should not be having entries for the alternate
+ * interfaces. This function has to insert these entries in the
+ * hostHashTable.
+ *
+ * All addresses are in network byte order.
+ */
+int
+removeInterfaceAddr_r(struct host *host, afs_uint32 addr, afs_uint16 port)
+{
+    int i;
+    int number;
+    int found;
+    struct Interface *interface;
+    char hoststr[16], hoststr2[16];
+
+    assert(host);
+    assert(host->interface);
+
+    ViceLog(125, ("removeInterfaceAddr : host %s:d addr %s:%d\n", 
+                  afs_inet_ntoa_r(host->host, hoststr), ntohs(host->port), 
+                  afs_inet_ntoa_r(addr, hoststr2), ntohs(port)));
+
+    /*
+     * Make sure this address is on the list of known addresses
+     * for this host.
+     */
+    interface = host->interface;
+    number = host->interface->numberOfInterfaces;
+    for (i = 0, found = 0; i < number; i++) {
+       if (interface->interface[i].addr == addr &&
+           interface->interface[i].port == port) {
+           found = 1;
+           break;
+       }
+    }
+    if (found) {
+       number--;
+       for (; i < number; i++) {
+           interface->interface[i].addr = interface->interface[i+1].addr;
+           interface->interface[i].port = interface->interface[i+1].port;
+       }
+       interface->numberOfInterfaces = number;
+    }
+
+    /*
+     * Remove the hash table entry for this address
+     */
+    hashDelete_r(addr, port, host);
+
+    return 0;
+}
+
+
 /* Host is returned held */
 struct host *
 h_GetHost_r(struct rx_connection *tcon)
@@ -1283,13 +1338,38 @@ h_GetHost_r(struct rx_connection *tcon)
                    /* This is a new address for an existing host. Update
                     * the list of interfaces for the existing host and
                     * delete the host structure we just allocated. */
+                   if (oldHost->host != haddr || oldHost->port != hport) {
                    ViceLog(25,
                            ("CB: new addr %s:%d for old host %s:%d\n",
                             afs_inet_ntoa_r(host->host, hoststr),
-                            ntohs(host->port), afs_inet_ntoa_r(oldHost->host,
-                                                               hoststr2),
+                               ntohs(host->port), 
+                               afs_inet_ntoa_r(oldHost->host, hoststr2),
                             ntohs(oldHost->port)));
+                       if (oldHost->host == haddr) {
+                           /* We have just been contacted by a client behind a NAT */
+                           removeInterfaceAddr_r(oldHost, oldHost->host, oldHost->port);
+                       } else {
+                           int i, found;
+                           struct Interface *interface = oldHost->interface;
+                           int number = oldHost->interface->numberOfInterfaces;
+                           for (i = 0, found = 0; i < number; i++) {
+                               if (interface->interface[i].addr == haddr &&
+                                   interface->interface[i].port != hport) {
+                                   found = 1;
+                                   break;
+                               }
+                           }
+                           if (found) {
+                               /* We have just been contacted by a client that has been
+                                * seen from behind a NAT and at least one other address.
+                                */
+                               removeInterfaceAddr_r(oldHost, haddr, interface->interface[i].port);
+                           }
+                       }
                    addInterfaceAddr_r(oldHost, haddr, hport);
+                       oldHost->host = haddr;
+                       oldHost->port = hport;
+                   }
                    host->hostFlags |= HOSTDELETED;
                    h_Unlock_r(host);
                    if (!held)
@@ -1323,9 +1403,12 @@ h_GetHost_r(struct rx_connection *tcon)
                        ("CB: RCallBackConnectBack failed for %s:%d\n",
                         hoststr, ntohs(host->port)));
                host->hostFlags |= VENUSDOWN;
-           } else
+           } else {
+               ViceLog(125,
+                       ("CB: RCallBackConnectBack succeeded for %s:%d\n",
+                        hoststr, ntohs(host->port)));
                host->hostFlags |= RESETDONE;
-
+           }
        }
        if (caps.Capabilities_val
            && (caps.Capabilities_val[0] & CLIENT_CAPABILITY_ERRORTRANS))