patchpanel: mcast: improve logs

BUG=b:163386838
TEST=Unit tests

Change-Id: I0a18168c288f4dafbe0ee6bae0ea5814f4af13bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2354127
Reviewed-by: Jason Jeremy Iman <jasongustaman@chromium.org>
Reviewed-by: Garrick Evans <garrick@chromium.org>
Tested-by: Hugo Benichi <hugobenichi@google.com>
Commit-Queue: Hugo Benichi <hugobenichi@google.com>
diff --git a/patchpanel/multicast_proxy.cc b/patchpanel/multicast_proxy.cc
index 45294fe..7aa6cec 100644
--- a/patchpanel/multicast_proxy.cc
+++ b/patchpanel/multicast_proxy.cc
@@ -67,7 +67,8 @@
     LOG(INFO) << "Starting mDNS forwarding between " << dev_ifname << " and "
               << msg.br_ifname();
     if (!mdns_fwd->second->AddGuest(msg.br_ifname())) {
-      LOG(WARNING) << "mDNS forwarder could not be started on " << dev_ifname;
+      LOG(WARNING) << "mDNS forwarder could not be started between "
+                   << dev_ifname << " and " << msg.br_ifname();
     }
 
     if (ssdp_fwd == ssdp_fwds_.end()) {
@@ -80,7 +81,8 @@
     LOG(INFO) << "Starting SSDP forwarding between " << dev_ifname << " and "
               << msg.br_ifname();
     if (!ssdp_fwd->second->AddGuest(msg.br_ifname())) {
-      LOG(WARNING) << "SSDP forwarder could not be started on " << dev_ifname;
+      LOG(WARNING) << "SSDP forwarder could not be started on " << dev_ifname
+                   << " and " << msg.br_ifname();
     }
 
     if (bcast_fwd == bcast_fwds_.end()) {
@@ -92,7 +94,8 @@
     LOG(INFO) << "Starting broadcast forwarding between " << dev_ifname
               << " and " << msg.br_ifname();
     if (!bcast_fwd->second->AddGuest(msg.br_ifname())) {
-      LOG(WARNING) << "SSDP forwarder could not be started on " << dev_ifname;
+      LOG(WARNING) << "Broadcast forwarder could not be started on "
+                   << dev_ifname << " and " << msg.br_ifname();
     }
 
     return;