RDM receiver

  hints = fi_allocinfo();
  hints->ep_attr->type  = FI_EP_RDM;
  hints->caps = FI_MSG;
  
  fi_getinfo(FI_VERSION(1, 1), "0.0.0.0", "12345, FI_SOURCE, hints, &socket->fi);
  fi_fabric(socket->fi->fabric_attr, &socket->fabric, &socket->prov_ctx);
  fi_domain(socket->fabric, socket->fi, &socket->domain, &socket->prov_ctx);
  fi_endpoint(socket->domain, socket->fi, &socket->ep, &socket->prov_ctx);

  struct fi_av_attr av_attr;
  av_attr.type = socket->fi->domain_attr->av_type;  /* type of AV */
  av_attr.count = 1;                                /* expected # entries for AV */
  av_attr.ep_per_node = 0;                          /* # endpoints per fabric address */
  av_attr.name = NULL;                              /* system name of AV */
  av_attr.map_addr = 0;                             /* base mmap address */
  av_attr.flags = 0;                                /* operation flags */

  fi_av_open(socket->domain, &av_attr, &socket->av, &socket->prov_ctx);

  fi_ep_bind(socket->ep, &socket->av->fid, 0);

  struct fi_cq_attr cq_attr;
  cq_attr.size = socket->fi->rx_attr->size;     /* # entries for CQ */
  cq_attr.flags = 0;                            /* operation flags */
  cq_attr.format = FI_CQ_FORMAT_CONTEXT;        /* completion format */
  cq_attr.wait_obj= FI_WAIT_NONE;               /* requested wait object */
  cq_attr.signaling_vector = 0;                 /* interrupt affinity */
  cq_attr.wait_cond = FI_CQ_COND_NONE;          /* wait condition format */
  cq_attr.wait_set = NULL;                      /* optional wait set */

  fi_cq_open(socket->domain, &cq_attr, &socket->cq, NULL);
  fi_ep_bind((socket->ep), &socket->cq->fid, FI_TRANSMIT|FI_RECV);

  fi_enable(socket->ep);

  fi_mr_reg(socket->domain, buf->data, buf->size, access, 0, 0, 0, &buf->mr,
                      &socket->prov_ctx);
  desc = fi_mr_desc(buf->mr);
  fi_recv(socket->ep, buf->data, buf->size, desc, FI_ADDR_UNSPEC, &socket->prov_ctx); // succeeds

RDM sender

  hints = fi_allocinfo();
  hints->ep_attr->type  = FI_EP_RDM;
  hints->caps = FI_MSG;
 
  fi_getinfo(FI_VERSION(1, 1), "192.168.56.2", "12345, 0, hints, &socket->fi);
  fi_fabric(socket->fi->fabric_attr, &socket->fabric, &socket->prov_ctx);
  fi_domain(socket->fabric, socket->fi, &socket->domain, &socket->prov_ctx);
  fi_endpoint(socket->domain, socket->fi, &socket->ep, &socket->prov_ctx);

  struct fi_av_attr av_attr;
  av_attr.type = socket->fi->domain_attr->av_type;   /* type of AV */
  av_attr.count = 1;                                 /* expected # entries for AV */
  av_attr.ep_per_node = 0;                           /* # endpoints per fabric address */
  av_attr.name = NULL;                               /* system name of AV */
  av_attr.map_addr = 0;                              /* base mmap address */
  av_attr.flags = 0;                                 /* operation flags */

  fi_av_open(socket->domain, &av_attr, &socket->av, &socket->prov_ctx);
  fi_ep_bind(socket->ep, &socket->av->fid, 0);

  struct fi_cq_attr cq_attr;
  cq_attr.size =  socket->fi->tx_attr->size;   /* # entries for CQ */
  cq_attr.flags = 0;                           /* operation flags */
  cq_attr.format = FI_CQ_FORMAT_CONTEXT;       /* completion format */
  cq_attr.wait_obj= FI_WAIT_NONE;              /* requested wait object */
  cq_attr.signaling_vector = 0;                /* interrupt affinity */
  cq_attr.wait_cond = FI_CQ_COND_NONE;         /* wait condition format */
  cq_attr.wait_set = NULL;                     /* optional wait set */

  fi_cq_open(socket->domain, &cq_attr, &socket->cq, NULL);
  fi_ep_bind((socket->ep), &socket->cq->fid, FI_TRANSMIT|FI_RECV);
  fi_enable(socket->ep);

  fi_mr_reg(socket->domain, buf->data, buf->size, access, 0, 0, 0, &buf->mr, &config.socket.prov_ctx);
  
  fi_addr_t addr;
  fi_av_insert(socket->av, socket->fi->dest_addr, 1, &addr, 0, &config.socket.prov_ctx);
  desc = fi_mr_desc(buf->mr);

  fi_send(config.socket.ep, buf->data, buf->size, desc, addr, &config.socket.prov_ctx);
  // returns -11: Resource temporarily unavailable