Avoid netlink socket address conflict
NetlinkManager previously bound all netlink sockets with nl_pid =
getpid(). Unfortunately only the first such socket is allowed to claim
nl_pid = getpid(). The kernel is happy to assign this value
automatically if nl_pid = 0. For more information on nl_pid see "man 7
netlink".
When NFLogListener was added, it created a socket with a kernel assigned
nl_pid, unfortunately the kernel assigns getpid() to the first such
socket and listener was initialized earlier in the startup process than
NetlinkManager.
This change alters NetlinkManager to request a kernel assigned nl_pid and
defensively moves the initialization of NFLogListener later in the
startup sequence to favor proper operation of existing code in
NetlinkManager. Error logging is also slightly improved.
Test: as follows
- built
- flashed
- booted
- "runtest -x .../netd_unit_test.cpp" passes
- "cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t
android.os.cts.StrictModeTest" passes
Bug: 62353125
Change-Id: I9c1c76e5769de75ff624bf43634ac4061c447a72
diff --git a/server/NetlinkManager.cpp b/server/NetlinkManager.cpp
index 7a7627a..698de9f 100644
--- a/server/NetlinkManager.cpp
+++ b/server/NetlinkManager.cpp
@@ -77,7 +77,8 @@
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
- nladdr.nl_pid = getpid();
+ // Kernel will assign a unique nl_pid if set to zero.
+ nladdr.nl_pid = 0;
nladdr.nl_groups = groups;
if ((*sock = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, netlinkFamily)) < 0) {
diff --git a/server/main.cpp b/server/main.cpp
index 50570fd..27596f7 100644
--- a/server/main.cpp
+++ b/server/main.cpp
@@ -83,19 +83,8 @@
exit(1);
};
- std::unique_ptr<NFLogListener> logListener;
- {
- auto result = makeNFLogListener();
- if (!isOk(result)) {
- ALOGE("Unable to create NFLogListener: %s", result.status().msg().c_str());
- exit(1);
- }
- logListener = std::move(result.value());
- }
-
gCtls = new android::net::Controllers();
gCtls->init();
- gCtls->wakeupCtrl.init(logListener.get());
CommandListener cl;
nm->setBroadcaster((SocketListener *) &cl);
@@ -105,6 +94,21 @@
exit(1);
}
+ std::unique_ptr<NFLogListener> logListener;
+ {
+ auto result = makeNFLogListener();
+ if (!isOk(result)) {
+ ALOGE("Unable to create NFLogListener: %s", toString(result).c_str());
+ exit(1);
+ }
+ logListener = std::move(result.value());
+ auto status = gCtls->wakeupCtrl.init(logListener.get());
+ if (!isOk(result)) {
+ ALOGE("Unable to init WakeupController: %s", toString(result).c_str());
+ // We can still continue without wakeup packet logging.
+ }
+ }
+
// Set local DNS mode, to prevent bionic from proxying
// back to this service, recursively.
setenv("ANDROID_DNS_MODE", "local", 1);