Method ProcessBatch

core/modules/ip_checksum.cc:37–77

#include "../utils/ip.h"

void IPChecksum::ProcessBatch(Context *ctx, bess::PacketBatch *batch) {
  using bess::utils::Ethernet;
  using bess::utils::Ipv4;
  using bess::utils::Vlan;
  using bess::utils::be16_t;

  int cnt = batch->cnt();

  for (int i = 0; i < cnt; i++) {
    Ethernet *eth = batch->pkts()[i]->head_data<Ethernet *>();
    void *data = eth + 1;
    Ipv4 *ip;

    be16_t ether_type = eth->ether_type;

    if (ether_type == be16_t(Ethernet::Type::kQinQ)) {
      Vlan *qinq = reinterpret_cast<Vlan *>(data);
      data = qinq + 1;
      ether_type = qinq->ether_type;
      if (ether_type != be16_t(Ethernet::Type::kVlan)) {
        continue;
      }
    }

    if (ether_type == be16_t(Ethernet::Type::kVlan)) {
      Vlan *vlan = reinterpret_cast<Vlan *>(data);
      data = vlan + 1;
      ether_type = vlan->ether_type;
    }

    if (ether_type == be16_t(Ethernet::Type::kIpv4)) {
      ip = reinterpret_cast<Ipv4 *>(data);
    } else {
      continue;
    }

    ip->checksum = CalculateIpv4Checksum(*ip);
  }

  RunNextModule(ctx, batch);
}

ADD_MODULE(IPChecksum, "ip_checksum", "recomputes the IPv4 checksum")