mpmd: Fixed MPM marking wrong device as reachable

During MPMd find routine, added a check when connecting to a CHDR
interface to make sure we're talking to the correct device.
Without this check MPMd would sometimes incorrectly mark a device as
reachable because they shared an addr (ie. 192.168.10.2 existed on
multiple devices).

1 files changed, 12 insertions, 1 deletions

diff --git a/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp b/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp
index 244fab344..8cad29f6b 100644
--- a/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp
+++ b/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp
@@ -271,7 +271,18 @@ boost::optional<device_addr_t> mpmd_mboard_impl::is_device_reachable(
                 "Was able to ping device, trying RPC connection.");
             auto chdr_rpcc = uhd::rpc_client::make(chdr_addr, rpc_port);
             chdr_rpcc->set_timeout(MPMD_SHORT_RPC_TIMEOUT);
-            chdr_rpcc->request<dev_info>("get_device_info");
+            auto dev_info_chdr = chdr_rpcc->request<dev_info>("get_device_info");
+            if (dev_info_chdr["serial"] != device_info_dict["serial"]) {
+                UHD_LOG_DEBUG("MPMD", boost::format(
+                    "Connected to CHDR interface, but got wrong device. "
+                    "Tried to reach serial %s, got %s")
+                     % device_info_dict["serial"] % dev_info_chdr["serial"]);
+                return boost::optional<device_addr_t>();
+            } else {
+                UHD_LOG_TRACE("MPMD", boost::format(
+                    "Reachable device matches expected device (serial=%s)")
+                    % device_info_dict["serial"] );
+            }
             device_addr_t device_addr_copy = device_addr;
             device_addr_copy["addr"] = chdr_addr;
             return boost::optional<device_addr_t>(device_addr_copy);