Implement waiting for IPv4 address for an interface

Bug: 239577572
Test: build, flash, check Internet
Change-Id: I339d6ae595fac13690a90d98ef82a6659819406c
diff --git a/automotive/can/1.0/default/libnetdevice/ifreqs.cpp b/automotive/can/1.0/default/libnetdevice/ifreqs.cpp
index 8df6434..8471173 100644
--- a/automotive/can/1.0/default/libnetdevice/ifreqs.cpp
+++ b/automotive/can/1.0/default/libnetdevice/ifreqs.cpp
@@ -47,7 +47,7 @@
     return params;
 }
 
-bool send(unsigned long request, struct ifreq& ifr) {
+int trySend(unsigned long request, struct ifreq& ifr) {
     const auto sp = getSocketParams(socketDomain);
     base::unique_fd sock(socket(sp.domain, sp.type, sp.protocol));
     if (!sock.ok()) {
@@ -55,7 +55,12 @@
         return false;
     }
 
-    if (ioctl(sock.get(), request, &ifr) < 0) {
+    if (ioctl(sock.get(), request, &ifr) < 0) return errno;
+    return 0;
+}
+
+bool send(unsigned long request, struct ifreq& ifr) {
+    if (trySend(request, ifr) != 0) {
         PLOG(ERROR) << "ioctl(" << std::hex << request << std::dec << ") failed";
         return false;
     }