ARP.cpp

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#include <arpa/inet.h>
#include <rte_arp.h>
#include <rte_ethdev.h>
 
#include <iomanip>
#include <iostream>
#include <sstream>
 
#include "dpdklibs/arp/ARP.hpp"
 
namespace dunedaq {
namespace dpdklibs {
namespace arp {
 
void
pktgen_send_garp(struct rte_mbuf* m, uint32_t port_id, rte_be32_t ip_add_bin)
{
  struct rte_ether_hdr* eth = rte_pktmbuf_mtod(m, struct rte_ether_hdr*);
  struct rte_arp_hdr* arp = (struct rte_arp_hdr*)&eth[1];
 
  /* src and dest addr */
  memset(&eth->dst_addr, 0xFF, 6);
  // MAC addr of port
  struct rte_ether_addr mac_addr;
  rte_eth_macaddr_get(port_id, &mac_addr);
  rte_ether_addr_copy(&mac_addr, &eth->src_addr);
  // Set ETH type
  eth->ether_type = htons(RTE_ETHER_TYPE_ARP);
 
  memset(arp, 0, sizeof(struct rte_arp_hdr));
  rte_memcpy(&arp->arp_data.arp_sha, &mac_addr, 6);
 
  inetAddrCopy(&arp->arp_data.arp_sip, &ip_add_bin);
 
  rte_memcpy(&arp->arp_data.arp_tha, &mac_addr, 6);
  inetAddrCopy(&arp->arp_data.arp_tip, &ip_add_bin);
 
  /* Fill in the rest of the ARP packet header */
  arp->arp_hardware = htons(RTE_ARP_HRD_ETHER);
  arp->arp_protocol = htons(RTE_ETHER_TYPE_IPV4);
  arp->arp_hlen = 6;
  arp->arp_plen = 4;
  arp->arp_opcode = htons(RTE_ARP_OP_REQUEST);
 
  m->pkt_len = 60;
  m->data_len = 60;
 
  struct rte_mbuf* arp_tx_mbuf[1];
  arp_tx_mbuf[0] = m;
 
  std::string srcaddr = dunedaq::dpdklibs::udp::get_ipv4_decimal_addr_str(
    dunedaq::dpdklibs::udp::ip_address_binary_to_dotdecimal(rte_be_to_cpu_32(arp->arp_data.arp_sip)));
  std::string dstaddr = dunedaq::dpdklibs::udp::get_ipv4_decimal_addr_str(
    dunedaq::dpdklibs::udp::ip_address_binary_to_dotdecimal(rte_be_to_cpu_32(arp->arp_data.arp_tip)));
  std::string localaddr = dunedaq::dpdklibs::udp::get_ipv4_decimal_addr_str(
    dunedaq::dpdklibs::udp::ip_address_binary_to_dotdecimal(rte_be_to_cpu_32(ip_add_bin)));
  TLOG_DEBUG(10) << "GARP SRC IP: " << srcaddr;
  TLOG_DEBUG(10) << "GARP DEST IP: " << dstaddr;
  TLOG_DEBUG(10) << "LOCAL IP: " << localaddr;
 
  rte_eth_tx_burst(port_id, 0, arp_tx_mbuf, 1);
}
 
inline void
hex_digits_to_stream(std::ostringstream& ostrs, int value, char separator = ':', char fill = '0', int digits = 2)
{
  ostrs << std::setfill(fill) << std::setw(digits) << std::hex << value << std::dec << separator;
}
 
void
pktgen_process_arp(struct rte_mbuf* m, uint32_t port_id, rte_be32_t ip_add_bin)
{
  struct rte_ether_hdr* eth = rte_pktmbuf_mtod(m, struct rte_ether_hdr*);
  struct rte_arp_hdr* arp = (struct rte_arp_hdr*)&eth[1];
 
  if (arp->arp_opcode == rte_cpu_to_be_16(RTE_ARP_OP_REQUEST)) {
    arp->arp_opcode = rte_cpu_to_be_16(RTE_ARP_OP_REPLY);
 
    /* Grab the source MAC addresses */
    struct rte_ether_addr mac_addr;
    rte_eth_macaddr_get(port_id, &mac_addr);
 
    std::string srcaddr = dunedaq::dpdklibs::udp::get_ipv4_decimal_addr_str(
      dunedaq::dpdklibs::udp::ip_address_binary_to_dotdecimal(rte_be_to_cpu_32(arp->arp_data.arp_sip)));
    std::string dstaddr = dunedaq::dpdklibs::udp::get_ipv4_decimal_addr_str(
      dunedaq::dpdklibs::udp::ip_address_binary_to_dotdecimal(rte_be_to_cpu_32(arp->arp_data.arp_tip)));
    std::string localaddr = dunedaq::dpdklibs::udp::get_ipv4_decimal_addr_str(
      dunedaq::dpdklibs::udp::ip_address_binary_to_dotdecimal(rte_be_to_cpu_32(ip_add_bin)));
 
    TLOG_DEBUG(10) << "ARP SRC IP: " << srcaddr;
    TLOG_DEBUG(10) << "ARP DEST IP: " << dstaddr;
    TLOG_DEBUG(10) << "ARP LOCAL IP: " << localaddr;
 
    // Bail out if not our ipaddress
    if (arp->arp_data.arp_tip != ip_add_bin)
      return;
 
    TLOG_DEBUG(10) << "ARP Received " << dstaddr << " I'm the target " << localaddr << " (port id = " << port_id << ")";
 
    /* Swap the two MAC addresses */
    ethAddrSwap(&arp->arp_data.arp_sha, &arp->arp_data.arp_tha);
 
    /* Swap the two IP addresses */
    inetAddrSwap(&arp->arp_data.arp_tip, &arp->arp_data.arp_sip);
 
    /* Set the packet to ARP reply */
    arp->arp_opcode = htons(RTE_ARP_OP_REPLY);
 
    /* Swap the MAC addresses */
    ethAddrSwap(&eth->dst_addr, &eth->src_addr);
 
    /* Copy in the MAC address for the reply. */
    rte_memcpy(&arp->arp_data.arp_sha, &mac_addr, 6);
    rte_memcpy(&eth->src_addr, &mac_addr, 6);
 
    struct rte_mbuf* arp_tx_mbuf[1];
    arp_tx_mbuf[0] = m;
 
    rte_eth_tx_burst(port_id, 0, arp_tx_mbuf, 1);
    TLOG_DEBUG(10) << "Sending ARP reply";
 
    /* No need to free mbuf as it was reused */
    return;
  }
}
 
} // namespace arp
} // namespace dpdklibs
} // namespace dunedaq