Add MPLS push module

bessctl/conf/samples/mpls_push.bess

@@ -0,0 +1,11 @@
+import scapy.all as scapy
+
+eth = scapy.Ether(src='02:1e:67:9f:4d:ae', dst='06:16:3e:1b:72:32')
+ip = scapy.IP(src='192.168.0.1', dst='10.0.0.1')
+udp = scapy.UDP(sport=10001, dport=10002)
+test_packet = bytes(eth/ip/udp)
+
+mpls_push::MPLSPush()
+mpls_push.set(label=7, ttl=64, tc=0, is_bottom_of_stack=True)
+
+Source() -> Rewrite(templates=[test_packet]) -> mpls_push -> Sink()

core/modules/mpls_push.cc

@@ -0,0 +1,52 @@
+#include "mpls_push.h"
+
+#include "../utils/endian.h"
+#include "../utils/ether.h"
+#include "../utils/mpls.h"
+
+using bess::utils::Ethernet;
+using bess::utils::be16_t;
+using bess::utils::Mpls;
+
+const Commands MPLSPush::cmds = {{"set", "MplsPushArg",
+                                  MODULE_CMD_FUNC(&MPLSPush::CommandSet),
+                                  Command::THREAD_UNSAFE}};
+
+MPLSPush::MPLSPush() : label_(0), ttl_(64), tc_(0), is_bottom_of_stack_(true) {}
+
+
+CommandResponse MPLSPush::Init(const bess::pb::MplsPushArg &arg) {
+  return CommandSet(arg);
+}
+
+void MPLSPush::ProcessBatch(bess::PacketBatch *batch) {
+  int cnt = batch->cnt();
+  for (int i = 0; i < cnt; i++) {
+    bess::Packet *pkt = batch->pkts()[i];
+    Ethernet *eth = pkt->head_data<Ethernet *>();
+
+    Ethernet::Address src_addr = eth->src_addr;
+    Ethernet::Address dst_addr = eth->dst_addr;
+
+    pkt->prepend(4);
+    eth = pkt->head_data<Ethernet *>();
+    eth->src_addr = src_addr;
+    eth->dst_addr = dst_addr;
+    eth->ether_type = be16_t(Ethernet::Type::kMpls);
+
+    Mpls *mpls_hdr = reinterpret_cast<Mpls *>(eth + 1);
+    mpls_hdr->SetEntry(label_, ttl_, tc_, is_bottom_of_stack_);
+  }
+
+  RunNextModule(batch);
+}
+
+CommandResponse MPLSPush::CommandSet(const bess::pb::MplsPushArg &arg) {
+  label_ = arg.label();
+  ttl_ = arg.ttl();
+  is_bottom_of_stack_ = arg.is_bottom_of_stack();
+  tc_ = arg.tc();
+  return CommandSuccess();
+}
+
+ADD_MODULE(MPLSPush, "mpls_push", "Push MPLS label")

core/modules/mpls_push.h

@@ -0,0 +1,29 @@
+#ifndef BESS_MODULES_MPLSPUSH_H_
+#define BESS_MODULES_MPLSPUSH_H_
+
+#include "../module.h"
+#include "../module_msg.pb.h"
+
+class MPLSPush final : public Module {
+ public:
+  static const gate_idx_t kNumIGates = 1;
+  static const gate_idx_t kNumOGates = 1;
+
+  static const Commands cmds;
+
+  MPLSPush();  // constructor
+
+  CommandResponse Init(const bess::pb::MplsPushArg &arg);
+
+  void ProcessBatch(bess::PacketBatch *batch) override;
+
+  CommandResponse CommandSet(const bess::pb::MplsPushArg &arg);
+
+ private:
+  uint32_t label_;
+  uint8_t ttl_;
+  uint8_t tc_;
+  bool is_bottom_of_stack_;
+};
+
+#endif  // BESS_MODULES_MPLSPUSH_H_

protobuf/module_msg.proto

@@ -995,3 +995,16 @@ message MplsPopArg {
    bool remove_eth_header = 1; // Remove ETH header with the pop
    uint32 next_eth_type = 2; /// The next ETH type to set
 }
+
+/**
+ * The MPLS push module adds MPLS label
+ *
+ * __Input Gates__: 1
+ * __Output Gates__: 1
+ */
+message MplsPushArg {
+   uint32 label = 1;
+   uint32 ttl = 2;
+   uint32 tc = 3;
+   bool is_bottom_of_stack = 4;
+}