commit 0b0156887b8f575d8162f508f54c0c4e770a1dc1
author Davide Pesavento <davidepesa@gmail.com> Mon Dec 12 21:00:04 2022 -0500
committer Davide Pesavento <davidepesa@gmail.com> Mon Dec 12 22:01:28 2022 -0500
tree 1a956a6a4b0c081a42b95583a20dfc20f892a229
parent 6b78a53cf75d01a7223d6adcd5a239c2a8ea2192

face: put the pcap handle in non-blocking mode

This prevents NFD from getting stuck in pcap_next_ex()
when the network interface goes down

Change-Id: I5760fcc7c950b46aecb7619bd889508ee24133aa

daemon/face/ethernet-transport.cpp

diff --git a/daemon/face/ethernet-transport.cpp b/daemon/face/ethernet-transport.cpp
index c122a80..a1c23f2 100644
--- a/daemon/face/ethernet-transport.cpp
+++ b/daemon/face/ethernet-transport.cpp
@@ -167,7 +167,7 @@
 
   auto [pkt, readErr] = m_pcap.readNextPacket();
   if (pkt.empty()) {
-    NFD_LOG_FACE_WARN("Read error: " << readErr);
+    NFD_LOG_FACE_DEBUG("Read error: " << readErr);
   }
   else {
     auto [eh, frameErr] = ethernet::checkFrameHeader(pkt, m_srcAddress,

daemon/face/pcap-helper.cpp

diff --git a/daemon/face/pcap-helper.cpp b/daemon/face/pcap-helper.cpp
index 637faaf..230e5af 100644
--- a/daemon/face/pcap-helper.cpp
+++ b/daemon/face/pcap-helper.cpp
@@ -69,6 +69,10 @@
       NDN_THROW(Error("pcap_activate: " + std::string(pcap_statustostr(ret))));
   });
 
+  char errbuf[PCAP_ERRBUF_SIZE] = {};
+  if (pcap_setnonblock(m_pcap, 1, errbuf) < 0)
+    NDN_THROW(Error("pcap_setnonblock: " + std::string(errbuf)));
+
   if (pcap_set_datalink(m_pcap, dlt) < 0)
     NDN_THROW(Error("pcap_set_datalink: " + getLastError()));
 
@@ -136,7 +140,7 @@
   if (ret < 0)
     return {span<uint8_t>{}, getLastError()};
   else if (ret == 0)
-    return {span<uint8_t>{}, "timed out"};
+    return {span<uint8_t>{}, "Nothing to read"};
   else
     return {{packet, header->caplen}, ""};
 }