Merge changes I05202eff,I26f5d5ee,I04534a09,Ia8978a12

* changes:
  Reject duplicate logger_nodes nodes
  Merge Connections as well as Channels
  Disallow logging timestamps without data
  Don't crash on channels with timestamps but no data
diff --git a/aos/network/sctp_lib.cc b/aos/network/sctp_lib.cc
index 4651d82..b9840c6 100644
--- a/aos/network/sctp_lib.cc
+++ b/aos/network/sctp_lib.cc
@@ -444,22 +444,19 @@
 }
 
 void SctpReadWrite::DoSetMaxSize() {
-  // Have the kernel give us a factor of 10 more.  This lets us have more than
-  // one full sized packet in flight.
-  size_t max_size = max_size_ * 10;
+  size_t max_size = max_size_;
 
-  CHECK_GE(ReadRMemMax(), max_size)
-      << "rmem_max is too low. To increase rmem_max temporarily, do sysctl "
-         "-w net.core.rmem_max="
-      << max_size;
+  // This sets the max packet size that we can send.
   CHECK_GE(ReadWMemMax(), max_size)
       << "wmem_max is too low. To increase wmem_max temporarily, do sysctl "
          "-w net.core.wmem_max="
       << max_size;
-  PCHECK(setsockopt(fd(), SOL_SOCKET, SO_RCVBUF, &max_size, sizeof(max_size)) ==
-         0);
   PCHECK(setsockopt(fd(), SOL_SOCKET, SO_SNDBUF, &max_size, sizeof(max_size)) ==
          0);
+
+  // The SO_RCVBUF option (also controlled by net.core.rmem_default) needs to be
+  // decently large but the actual size can be measured by tuning.  The defaults
+  // should be fine.  If it isn't big enough, transmission will fail.
 }
 
 bool SctpReadWrite::ProcessNotification(const Message *message) {
diff --git a/frc971/config/setup_roborio.sh b/frc971/config/setup_roborio.sh
index 47e1f7d..86f11d4 100755
--- a/frc971/config/setup_roborio.sh
+++ b/frc971/config/setup_roborio.sh
@@ -43,8 +43,6 @@
 
 ssh "admin@${ROBOT_HOSTNAME}" "sed -i 's/vm\.overcommit_memory=2/vm\.overcommit_memory=0/' /etc/sysctl.conf"
 
-ssh "admin@${ROBOT_HOSTNAME}" 'echo "net.core.wmem_max=1262560" >> /etc/sysctl.conf'
-ssh "admin@${ROBOT_HOSTNAME}" 'echo "net.core.rmem_max=1262560" >> /etc/sysctl.conf'
 ssh "admin@${ROBOT_HOSTNAME}" 'echo "vm.min_free_kbytes=4000" >> /etc/sysctl.conf'
 
 ssh "admin@${ROBOT_HOSTNAME}" mkdir "/lib/modules/4.14.87-rt49-cg-7.0.0f0-xilinx-zynq-189/kernel/net/sctp/ -p"