socket: uevent: use SO_RCVBUF instead of SO_RCVBUFFORCE

The SO_RCVBUFFORCE option requires the caller of uevent_create_socket()
to have net_admin capabilities.

Set platform default rcv/snd buffer sizes to 256kb that will always be
overridden by the device/target. However, it will allow
ueventd / healthd to use the uevent_create_socket() API w/o requiring
the net_admin capability.

Note: All devices override the buffer sizes according to the technology
maximum to at least ~8MB. So, the init.rc change here is to make sure
platform code can work w/o any overrides.

Test: no SELinux failures for healthd with 'net_admin' removed.

Bug: https://b/32733887

Change-Id: Ida346468cd550ad07901bf3a78ad508939849906
Signed-off-by: Sandeep Patil <sspatil@google.com>
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 8903255..249b9e2 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -125,6 +125,12 @@
     write /proc/sys/kernel/sched_rt_runtime_us 950000
     write /proc/sys/kernel/sched_rt_period_us 1000000
 
+    # Assign reasonable ceiling values for socket rcv/snd buffers.
+    # These should almost always be overridden by the target per the
+    # the corresponding technology maximums.
+    write /proc/sys/net/core/rmem_max  262144
+    write /proc/sys/net/core/wmem_max  262144
+
     # reflect fwmark from incoming packets onto generated replies
     write /proc/sys/net/ipv4/fwmark_reflect 1
     write /proc/sys/net/ipv6/fwmark_reflect 1