uint8_t set_gid()

in tensorflow_networking/verbs/rdma.cc [267:315]

• 46 lines of code
• 10 McCabe index (conditional complexity)

uint8_t set_gid(uint8_t port_num, ibv_context* context) {
  ibv_port_attr port_attr;
  string gid_str;
  int rc, i, gids_num = 0, v2_ip_num = 0;
  union ibv_gid gid;
  uint8_t gid_index = 0;

  rc = ibv_query_port(context, port_num, &port_attr);
  CHECK(!rc) << "Failed to query the port" << port_num;

  for (i = 0; i < port_attr.gid_tbl_len; i++) {
    rc = ibv_query_gid(context, port_num, i, &gid);
    CHECK(!rc) << "Failed to query gid to port " << (int)port_num << " index "
               << i;
    if (gid.global.interface_id) {
      gids_num++;
      if (gid.global.subnet_prefix == 0 &&
          is_gid_type_roce_v2(context, port_num, i)) {
        if (v2_ip_num == 0) {
          // can be overwritten by RDMA_GID_INDEX later
          gid_index = i;
        }
        v2_ip_num++;
      }
    }
  }
  switch (port_attr.link_layer) {
    case (IBV_LINK_LAYER_ETHERNET):
      gid_str = get_env_var("RDMA_GID_INDEX");
      if (!gid_str.empty()) {
        gid_index = stoi(gid_str);
        CHECK(gid_index < gids_num)
            << "RDMA_GID_INDEX should be less than GIDs amount" << gids_num;
      } else {
        CHECK(v2_ip_num <= 1)
            << "More than one IP is available, please specify GID_INDEX";
      }
      break;
    case (IBV_LINK_LAYER_INFINIBAND):  // no need in GID index
      break;
    default:
      LOG(INFO) << "Unknown port link layer. Currently supporting Ethernet and "
                   "InfiniBand only. ";
  }
  if (!is_gid_type_roce_v2(context, port_num, gid_index)) {
    LOG(INFO) << "RoCE v2 is not configured for GID_INDEX " << (int)gid_index;
  }
  return gid_index;
}