Support basic /proc/net/dev metrics for netstack

Fixes #506

PiperOrigin-RevId: 302540404

2 files changed, 105 insertions, 21 deletions

diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go
index 0692482e9..a8e2e8c24 100644
--- a/pkg/sentry/socket/netstack/stack.go
+++ b/pkg/sentry/socket/netstack/stack.go
@@ -200,36 +200,66 @@ func (s *Stack) SetTCPSACKEnabled(enabled bool) error {
 // Statistics implements inet.Stack.Statistics.
 func (s *Stack) Statistics(stat interface{}, arg string) error {
 	switch stats := stat.(type) {
+	case *inet.StatDev:
+		for _, ni := range s.Stack.NICInfo() {
+			if ni.Name != arg {
+				continue
+			}
+			// TODO(gvisor.dev/issue/2103) Support stubbed stats.
+			*stats = inet.StatDev{
+				// Receive section.
+				ni.Stats.Rx.Bytes.Value(),   // bytes.
+				ni.Stats.Rx.Packets.Value(), // packets.
+				0,                           // errs.
+				0,                           // drop.
+				0,                           // fifo.
+				0,                           // frame.
+				0,                           // compressed.
+				0,                           // multicast.
+				// Transmit section.
+				ni.Stats.Tx.Bytes.Value(),   // bytes.
+				ni.Stats.Tx.Packets.Value(), // packets.
+				0,                           // errs.
+				0,                           // drop.
+				0,                           // fifo.
+				0,                           // colls.
+				0,                           // carrier.
+				0,                           // compressed.
+			}
+			break
+		}
 	case *inet.StatSNMPIP:
 		ip := Metrics.IP
+		// TODO(gvisor.dev/issue/969) Support stubbed stats.
 		*stats = inet.StatSNMPIP{
-			0,                          // TODO(gvisor.dev/issue/969): Support Ip/Forwarding.
-			0,                          // TODO(gvisor.dev/issue/969): Support Ip/DefaultTTL.
+			0,                          // Ip/Forwarding.
+			0,                          // Ip/DefaultTTL.
 			ip.PacketsReceived.Value(), // InReceives.
-			0,                          // TODO(gvisor.dev/issue/969): Support Ip/InHdrErrors.
+			0,                          // Ip/InHdrErrors.
 			ip.InvalidDestinationAddressesReceived.Value(), // InAddrErrors.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/ForwDatagrams.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/InUnknownProtos.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/InDiscards.
+			0,                               // Ip/ForwDatagrams.
+			0,                               // Ip/InUnknownProtos.
+			0,                               // Ip/InDiscards.
 			ip.PacketsDelivered.Value(),     // InDelivers.
 			ip.PacketsSent.Value(),          // OutRequests.
 			ip.OutgoingPacketErrors.Value(), // OutDiscards.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/OutNoRoutes.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/ReasmTimeout.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/ReasmReqds.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/ReasmOKs.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/ReasmFails.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/FragOKs.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/FragFails.
-			0,                               // TODO(gvisor.dev/issue/969): Support Ip/FragCreates.
+			0,                               // Ip/OutNoRoutes.
+			0,                               // Support Ip/ReasmTimeout.
+			0,                               // Support Ip/ReasmReqds.
+			0,                               // Support Ip/ReasmOKs.
+			0,                               // Support Ip/ReasmFails.
+			0,                               // Support Ip/FragOKs.
+			0,                               // Support Ip/FragFails.
+			0,                               // Support Ip/FragCreates.
 		}
 	case *inet.StatSNMPICMP:
 		in := Metrics.ICMP.V4PacketsReceived.ICMPv4PacketStats
 		out := Metrics.ICMP.V4PacketsSent.ICMPv4PacketStats
+		// TODO(gvisor.dev/issue/969) Support stubbed stats.
 		*stats = inet.StatSNMPICMP{
-			0, // TODO(gvisor.dev/issue/969): Support Icmp/InMsgs.
+			0, // Icmp/InMsgs.
 			Metrics.ICMP.V4PacketsSent.Dropped.Value(), // InErrors.
-			0,                         // TODO(gvisor.dev/issue/969): Support Icmp/InCsumErrors.
+			0,                         // Icmp/InCsumErrors.
 			in.DstUnreachable.Value(), // InDestUnreachs.
 			in.TimeExceeded.Value(),   // InTimeExcds.
 			in.ParamProblem.Value(),   // InParmProbs.
@@ -241,7 +271,7 @@ func (s *Stack) Statistics(stat interface{}, arg string) error {
 			in.TimestampReply.Value(), // InTimestampReps.
 			in.InfoRequest.Value(),    // InAddrMasks.
 			in.InfoReply.Value(),      // InAddrMaskReps.
-			0,                         // TODO(gvisor.dev/issue/969): Support Icmp/OutMsgs.
+			0,                         // Icmp/OutMsgs.
 			Metrics.ICMP.V4PacketsReceived.Invalid.Value(), // OutErrors.
 			out.DstUnreachable.Value(),                     // OutDestUnreachs.
 			out.TimeExceeded.Value(),                       // OutTimeExcds.
@@ -277,15 +307,16 @@ func (s *Stack) Statistics(stat interface{}, arg string) error {
 		}
 	case *inet.StatSNMPUDP:
 		udp := Metrics.UDP
+		// TODO(gvisor.dev/issue/969) Support stubbed stats.
 		*stats = inet.StatSNMPUDP{
 			udp.PacketsReceived.Value(),     // InDatagrams.
 			udp.UnknownPortErrors.Value(),   // NoPorts.
-			0,                               // TODO(gvisor.dev/issue/969): Support Udp/InErrors.
+			0,                               // Udp/InErrors.
 			udp.PacketsSent.Value(),         // OutDatagrams.
 			udp.ReceiveBufferErrors.Value(), // RcvbufErrors.
-			0,                               // TODO(gvisor.dev/issue/969): Support Udp/SndbufErrors.
-			0,                               // TODO(gvisor.dev/issue/969): Support Udp/InCsumErrors.
-			0,                               // TODO(gvisor.dev/issue/969): Support Udp/IgnoredMulti.
+			0,                               // Udp/SndbufErrors.
+			0,                               // Udp/InCsumErrors.
+			0,                               // Udp/IgnoredMulti.
 		}
 	default:
 		return syserr.ErrEndpointOperation.ToError()
diff --git a/test/syscalls/linux/proc_net.cc b/test/syscalls/linux/proc_net.cc
index 05c952b99..4e23d1e78 100644
--- a/test/syscalls/linux/proc_net.cc
+++ b/test/syscalls/linux/proc_net.cc
@@ -92,6 +92,59 @@ TEST(ProcSysNetIpv4Sack, CanReadAndWrite) {
   EXPECT_EQ(buf, to_write);
 }
 
+// DeviceEntry is an entry in /proc/net/dev
+struct DeviceEntry {
+  std::string name;
+  uint64_t stats[16];
+};
+
+PosixErrorOr<std::vector<DeviceEntry>> GetDeviceMetricsFromProc(
+    const std::string dev) {
+  std::vector<std::string> lines = absl::StrSplit(dev, '\n');
+  std::vector<DeviceEntry> entries;
+
+  // /proc/net/dev prints 2 lines of headers followed by a line of metrics for
+  // each network interface.
+  for (unsigned i = 2; i < lines.size(); i++) {
+    // Ignore empty lines.
+    if (lines[i].empty()) {
+      continue;
+    }
+
+    std::vector<std::string> values =
+        absl::StrSplit(lines[i], ' ', absl::SkipWhitespace());
+
+    // Interface name + 16 values.
+    if (values.size() != 17) {
+      return PosixError(EINVAL, "invalid line: " + lines[i]);
+    }
+
+    DeviceEntry entry;
+    entry.name = values[0];
+    // Skip the interface name and read only the values.
+    for (unsigned j = 1; j < 17; j++) {
+      uint64_t num;
+      if (!absl::SimpleAtoi(values[j], &num)) {
+        return PosixError(EINVAL, "invalid value: " + values[j]);
+      }
+      entry.stats[j - 1] = num;
+    }
+
+    entries.push_back(entry);
+  }
+
+  return entries;
+}
+
+// TEST(ProcNetDev, Format) tests that /proc/net/dev is parsable and
+// contains at least one entry.
+TEST(ProcNetDev, Format) {
+  auto dev = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/net/dev"));
+  auto entries = ASSERT_NO_ERRNO_AND_VALUE(GetDeviceMetricsFromProc(dev));
+
+  EXPECT_GT(entries.size(), 0);
+}
+
 PosixErrorOr<uint64_t> GetSNMPMetricFromProc(const std::string snmp,
                                              const std::string& type,
                                              const std::string& item) {