get_ips.hpp

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#ifndef UTILITIES_INCLUDE_UTILITIES_GET_IPS_HPP_
#define UTILITIES_INCLUDE_UTILITIES_GET_IPS_HPP_
 
#include "logging/Logging.hpp"
#include "utilities/Issues.hpp"
 
#include <arpa/nameser.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <netinet/in.h>
#include <resolv.h>
#include <sys/types.h>
 
#include <cerrno> // NOLINT(runtime/output_format
#include <string>
#include <vector>
 
namespace dunedaq::utilities {
 
inline std::vector<std::string>
get_hostname_ips(std::string hostname)
{
  std::vector<std::string> output;
 
  TLOG_DEBUG(12) << "Name is " << hostname;
 
  struct addrinfo* addrinfo = nullptr;
  auto s = getaddrinfo(hostname.c_str(), nullptr, nullptr, &addrinfo);
 
  if (s != 0) {
    ers::error(NameNotFound(ERS_HERE, hostname, std::string(gai_strerror(s))));
    return output;
  }
 
  for (auto rp = addrinfo; rp != nullptr; rp = rp->ai_next) {
    char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV]; // NOLINT
 
    // Let's skip all the IPv6 here
    if (rp->ai_family == AF_INET6)
      continue;
 
    getnameinfo(rp->ai_addr, rp->ai_addrlen, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV);
    auto ipaddr = std::string(hbuf);
    bool duplicate = false;
    for (auto& ip : output) {
      if (ip == ipaddr) {
        duplicate = true;
        break;
      }
    }
    if (!duplicate) {
      TLOG_DEBUG(13) << "Found address " << ipaddr << " for hostname " << hostname;
      output.push_back(ipaddr);
    }
  }
 
  freeaddrinfo(addrinfo);
 
  return output;
}
 
inline std::string
get_interface_ip(std::string eth_device_name, bool throw_if_missing = false)
{
  std::string ipaddr = "0.0.0.0";
  char hostname[NI_MAXHOST]; // NOLINT This is a char array for interfacing with the C networking API
  if (gethostname(&hostname[0], NI_MAXHOST) == 0) {
    ipaddr = std::string(hostname);
  }
  bool eth_found = false;
  if (eth_device_name != "") {
    // Work out which ip address goes with this device
    struct ifaddrs* ifaddr = nullptr;
    getifaddrs(&ifaddr);
 
    for (auto ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next) {
      if (ifa->ifa_addr == nullptr || std::string(ifa->ifa_name) != eth_device_name) {
        continue;
      }
 
      char ip[NI_MAXHOST]; // NOLINT This is a char array for interfacing with the C networking API
      int status = getnameinfo(ifa->ifa_addr, sizeof(struct sockaddr_in), ip, NI_MAXHOST, nullptr, 0, NI_NUMERICHOST);
      if (status != 0) {
        continue;
      }
      eth_found = true;
      ipaddr = std::string(ip);
      break;
    }
    freeifaddrs(ifaddr);
 
    if (!eth_found) {
      auto err = InterfaceNotFound(ERS_HERE, eth_device_name);
 
      if (throw_if_missing)
        throw err;
      else
        ers::warning(err);
    }
  }
 
  return ipaddr;
}
 
} // namespace dunedaq::utilities
 
#endif // UTILITIES_INCLUDE_UTILITIES_GET_IPS_HPP_