网络编程常用函数

一、Linux 协议栈

1. IP 地址转换

• 将IP地址从点数格式转换成无符号长整型

struct sockaddr_in ina;
ina.sin_addr.s_addr = inet_addr("132.241.5.10");

• 将无符号长整型转换为点数格式

a1 = inet_ntoa(ina1.sin_addr); /* 这是198.92.129.1 */
a2 = inet_ntoa(ina2.sin_addr); /* 这是132.241.5.10 */
printf("address 1: %s ",a1);
printf("address 2: %s ",a2);
// 输出如下：
// address 1: 132.241.5.10
// address 2: 132.241.5.10

2. 字节顺序

• 将主机顺序转换为网络字节顺序

htons()
htonl()

• 将网络字节顺序转换为主机顺序

ntohs()
ntohl()

---

二、DPDK

1. 程序初始化

/* Check that there is an even number of ports to send/receive on. */
	// 获取有效网卡的个数
	nb_ports = rte_eth_dev_count_avail();
	if (nb_ports < 2 || (nb_ports & 1))
		rte_exit(EXIT_FAILURE, "Error: number of ports must be even\n");

2. 端口初始化

struct rte_eth_conf port_conf = {
	  .rxmode = {
		  .split_hdr_size = 0,
	  },
	  .txmode = {
		  .offloads =
		  DEV_TX_OFFLOAD_VLAN_INSERT |
			  DEV_TX_OFFLOAD_IPV4_CKSUM |
			  DEV_TX_OFFLOAD_UDP_CKSUM |
			  DEV_TX_OFFLOAD_TCP_CKSUM |
			  DEV_TX_OFFLOAD_SCTP_CKSUM |
			  DEV_TX_OFFLOAD_TCP_TSO,
	  },
  };
  struct rte_eth_txconf txq_conf;
  struct rte_eth_rxconf rxq_conf;
  struct rte_eth_dev_info dev_info;

  ret = rte_eth_dev_info_get(port_id, &dev_info);
  if (ret != 0)
	rte_exit(EXIT_FAILURE,
			 "Error during getting device (port %u) info: %s\n",
			 port_id, strerror(-ret));

  port_conf.txmode.offloads &= dev_info.tx_offload_capa;
  printf(":: initializing port: %d\n", port_id);
  ret = rte_eth_dev_configure(port_id,
							  nr_queues, nr_queues, &port_conf);
  if (ret < 0) {
	rte_exit(EXIT_FAILURE,
			 ":: cannot configure device: err=%d, port=%u\n",
			 ret, port_id);
  }

  rxq_conf = dev_info.default_rxconf;
  rxq_conf.offloads = port_conf.rxmode.offloads;