Fix the netlink socket read logic for dump/bulk-get

To accommodate a stream interface (TCP) to vRouter, logic was added to
detect when to break out of a socket receive in place of a clean sweep
of the socket buffer for datagram sockets (stream interface is blocking,
since non-blocking interface does not make sense for utilities) and that
logic has turned out to be buggy.

For a dump/bulk get, vRouter sends a response message, followed by the
bulk record message, followed by a netlink DONE message. The bulk record
message is limited to what can be held in a single page. If there are
more records to be fetched, more dump requests have to be sent with
appropriate last seen record, which serves as a marker.

With the current logic present in all the utilities, for a single dump
request, all messages are read from the socket except for the DONE. When
a subsequent dump request is sent with the last seen record and read is
performed on the socket, the DONE message is returned with no valid
sandesh message. Since the application knows that more records are to be
read, it sends the same dump request again, resulting in two identical
bulk record responses and duplicate outputs.

For dump/bulk-get, the fix ensures that all messages are read from the
socket till a DONE is processed.

Change-Id: Ia52dce5df9191abc30b9a5e9b76786e1fad4646f
Closes-BUG: #1459106

utils/mpls.c

@@ -56,7 +56,10 @@ vr_mpls_req_process(void *s_req)
    if (mpls_op == SANDESH_OP_DUMP)
        dump_marker = req->mr_label;
 
-   response_pending = false;
+   if (mpls_op != SANDESH_OP_DUMP)
+       response_pending = false;
+
+   return;
 }
 
 void
@@ -143,6 +146,8 @@ vr_mpls_op(void)
             if (resp->nl_op == SANDESH_REQUEST) {
                 sandesh_decode(resp->nl_data, resp->nl_len,
                                vr_find_sandesh_info, &ret);
+            } else if (resp->nl_type == NL_MSG_TYPE_DONE) {
+                response_pending = false;
             }
         }
 

utils/nh.c

@@ -249,7 +249,8 @@ vr_nexthop_req_process(void *s_req)
         dump_marker = req->nhr_id;
     }
 
-    response_pending = false;
+    if (command != 3)
+        response_pending = false;
     printf("\n");
 }
 
@@ -386,6 +387,8 @@ vr_nh_op(int opt, int mode, uint32_t nh_id, uint32_t if_id, uint32_t vrf_id,
             resp = nl_parse_reply(cl);
             if (resp->nl_op == SANDESH_REQUEST) {
                 sandesh_decode(resp->nl_data, resp->nl_len, vr_find_sandesh_info, &ret);
+            } else if (resp->nl_type == NL_MSG_TYPE_DONE) {
+                response_pending = false;
             }
         }
 

utils/rt.c

@@ -241,7 +241,9 @@ vr_route_req_process(void *s_req)
         printf(" %10d\n", rt->rtr_nh_id);
     }
 
-    response_pending = false;
+    if (cmd_op != SANDESH_OP_DUMP)
+        response_pending = false;
+
     return;
 }
 
@@ -406,9 +408,12 @@ vr_send_one_message(void)
     while (response_pending) {
         if ((ret = nl_recvmsg(cl)) > 0) {
             resp = nl_parse_reply(cl);
-            if (resp->nl_op == SANDESH_REQUEST)
+            if (resp->nl_op == SANDESH_REQUEST) {
                 sandesh_decode(resp->nl_data, resp->nl_len,
                                vr_find_sandesh_info, &ret);
+            } else if (resp->nl_type == NL_MSG_TYPE_DONE) {
+                response_pending = false;
+            }
         }
     }
     return resp_code;

utils/vif.c

@@ -343,7 +343,9 @@ vr_interface_req_process(void *s)
         vr_ifindex = req->vifr_idx;
     }
 
-    response_pending = false;
+    if (vr_op != SANDESH_OP_DUMP)
+        response_pending = false;
+
     return;
 }
 
@@ -494,6 +496,8 @@ vr_intf_send_msg(void *request, char *request_string)
             if (resp->nl_op == SANDESH_REQUEST) {
                 sandesh_decode(resp->nl_data, resp->nl_len,
                                vr_find_sandesh_info, &ret);
+            } else if (resp->nl_type == NL_MSG_TYPE_DONE) {
+                response_pending = false;
             }
         }
 

utils/vxlan.c

@@ -61,7 +61,8 @@ vr_vxlan_req_process(void *s_req)
 
    dump_marker = req->vxlanr_vnid;
 
-   response_pending = false;
+   if (vxlan_op != SANDESH_OP_DUMP)
+       response_pending = false;
 
    return;
 }
@@ -151,6 +152,8 @@ vr_vxlan_op(void)
             if (resp->nl_op == SANDESH_REQUEST) {
                 sandesh_decode(resp->nl_data, resp->nl_len,
                                vr_find_sandesh_info, &ret);
+            } else if (resp->nl_type == NL_MSG_TYPE_DONE) {
+                response_pending = false;
             }
         }