在RDMA传输中，RDMA读保护可以用于防止远程节点读取本地内存中的数据，以加强系统的安全性。以下是使用InfiniBand Verbs API实现本地内存操作的RDMA读保护的示例代码：

//设置内存访问权限，该内存只能由本地主机读写 ibv_mr* mr = ibv_reg_mr(pd, local_buffer, length, IBV_ACCESS_LOCAL_WRITE);

//获取本地主机ID struct ibv_device_attr device_attr; ibv_query_device(context, &device_attr); uint64_t local_id = device_attr.node_guid;

//建立QP struct ibv_qp_init_attr qp_init_attr; qp_init_attr.send_cq = cq; qp_init_attr.recv_cq = cq; qp_init_attr.qp_type = IBV_QPT_RC; qp_init_attr.cap.max_send_wr = 10; qp_init_attr.cap.max_recv_wr = 10; qp_init_attr.cap.max_send_sge = 1; qp_init_attr.cap.max_recv_sge = 1; struct ibv_qp* qp = ibv_create_qp(pd, &qp_init_attr);

//设置本地QP的地址 struct ibv_port_attr port_attr; ibv_query_port(context, 1, &port_attr); //1表示端口号 union ibv_gid gid; ibv_query_gid(context, 1, 0, &gid); //0表示GID的索引号 struct ibv_ah_attr ah_attr; memset(&ah_attr, 0, sizeof(ah_attr)); ah_attr.is_global = 1; ah_attr.grh.hop_limit = 1; ah_attr.grh.dgid = gid; ah_attr.grh.sgid_index = 0; ibv_attach_mcast(qp, &ah_attr);

//在本地地址向RDMA远端发送数据 struct ibv_send_wr send_wr; memset(&send_wr, 0, sizeof(send_wr)); send_wr.opcode = IBV_WR_RDMA_WRITE_WITH_IMM; send_wr.send_flags = IBV_SEND_SIGNALED; send_wr.imm_data = htonl(local_id); send_wr.sg_list = sge; send_wr.num_sge = 1; send_wr.wr.rdma.remote_addr = remote_buffer_addr; send_wr.wr.rdma.rkey = remote_buffer_rkey; ibv_post_send(qp, &send_wr, &bad_send_wr);

//在本地地址接收来自RDMA远端的数据 struct ibv_recv_wr recv_wr; memset(&recv_wr, 0, sizeof(recv_wr)); recv_wr.sg_list = sge;