as,rsrv: use real client IP instead of untrusted host name

modules/database/src/ioc/rsrv/camessage.c

@@ -861,6 +861,14 @@ static int host_name_action ( caHdrLargeArray *mp, void *pPayload,
         return RSRV_ERROR;
     }
 
+    /* after all validation */
+    if(asUseIP) {
+
+        DLOG (2, ( "CAS: host_name_action for \"%s\" ignores clist provided host name\n",
+            client->pHostName ) );
+        return RSRV_OK;
+    }
+
     /*
      * user name will not change if there isnt enough memory
      */

modules/database/src/ioc/rsrv/caservertask.c

@@ -1421,6 +1421,20 @@ struct client *create_tcp_client (SOCKET sock , const osiSockAddr *peerAddr)
     }
 
     client->addr = peerAddr->ia;
+    if(asUseIP) {
+        epicsUInt32 ip = ntohl(client->addr.sin_addr.s_addr);
+        client->pHostName = malloc(24);
+        if(!client->pHostName) {
+            destroy_client ( client );
+            return NULL;
+        }
+        epicsSnprintf(client->pHostName, 24,
+                      "%u.%u.%u.%u",
+                      (ip>>24)&0xff,
+                      (ip>>16)&0xff,
+                      (ip>>8)&0xff,
+                      (ip>>0)&0xff);
+    }
 
     /*
      * see TCP(4P) this seems to make unsolicited single events much

modules/database/src/ioc/rsrv/server.h

@@ -86,7 +86,7 @@ typedef struct client {
   ELLLIST               chanList;
   ELLLIST               chanPendingUpdateARList;
   ELLLIST               putNotifyQue;
-  struct sockaddr_in    addr;
+  struct sockaddr_in    addr; /* peer address, TCP only */
   epicsTimeStamp        time_at_last_send;
   epicsTimeStamp        time_at_last_recv;
   void                  *evuser;