#include <stdint.h>
#include <inttypes.h>
#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_cycles.h>
#include <rte_lcore.h>
#include <rte_mbuf.h>
#define RX_RING_SIZE 128 //接收环大小
#define TX_RING_SIZE 512 //发送环大小
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
#define BURST_SIZE 32
static const struct rte_eth_conf port_conf_default = {
.rxmode = { .max_rx_pkt_len = ETHER_MAX_LEN }
};
/* basicfwd.c: Basic DPDK skeleton forwarding example. */
/*
* Initializes a given port using global settings and with the RX buffers
* coming from the mbuf_pool passed as a parameter.
*/
/*
指定网口的队列数，本列中指定的是但队列
在tx、rx两个方向上，设置缓冲区
*/
static inline int
port_init(uint8_t port, struct rte_mempool *mbuf_pool)
{
struct rte_eth_conf port_conf = port_conf_default; //网口配置=默认的网口配置
const uint16_t rx_rings = 1, tx_rings = 1; //网口tx、rx队列的个数
int retval; //临时变量，返回值
uint16_t q; //临时变量，队列号
if (port >= rte_eth_dev_count())
return -1;
/* Configure the Ethernet device. */
//配置以太网口设备
//网口号、发送队列个数、接收队列个数、网口的配置
retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf); //设置网卡设备
if (retval != 0)
return retval;
/* Allocate and set up 1 RX queue per Ethernet port. */
//RX队列初始化
for (q = 0; q < rx_rings; q++) { //遍历指定网口的所有rx队列
//申请并设置一个收包队列
//指定网口，指定队列，指定队列RING的大小，指定SOCKET_ID号，指定队列选项（默认NULL），指定内存池
//其中rte_eth_dev_socket_id(port)不理解,通过port号来获取dev_socket_id??
//dev_socket_id作用未知，有待研究
retval = rte_eth_rx_queue_setup(port, q, RX_RING_SIZE,
rte_eth_dev_socket_id(port), NULL, mbuf_pool);
if (retval < 0)
return retval;
}
//TX队列初始化
/* Allocate and set up 1 TX queue per Ethernet port. */
for (q = 0; q < tx_rings; q++) { //遍历指定网口的所有tx队列
//申请并设置一个发包队列
//指定网口，指定队列，指定队列RING大小，指定SOCKET_ID号，指定选项（NULL为默认）
//??TX为何没指定内存池，此特征有待研究
retval = rte_eth_tx_queue_setup(port, q, TX_RING_SIZE, //申请并设置一个发包队列
rte_eth_dev_socket_id(port), NULL);
if (retval < 0)
return retval;
}
/* Start the Ethernet port. */
retval = rte_eth_dev_start(port); //启动网卡
if (retval < 0)
return retval;
/* Display the port MAC address. */
struct ether_addr addr;
rte_eth_macaddr_get(port, &addr); //获取网卡的MAC地址，并打印
printf("Port %u MAC: %02" PRIx8 " %02" PRIx8 " %02" PRIx8
" %02" PRIx8 " %02" PRIx8 " %02" PRIx8 "\n",
(unsigned)port,
addr.addr_bytes[0], addr.addr_bytes[1],
addr.addr_bytes[2], addr.addr_bytes[3],
addr.addr_bytes[4], addr.addr_bytes[5]);
/* Enable RX in promiscuous mode for the Ethernet device. */
rte_eth_promiscuous_enable(port); //设置网卡为混杂模式
return 0;
}
/*
* The lcore main. This is the main thread that does the work, reading from
* an input port and writing to an output port.
*/
/*
//业务函数入口点
//__attribute__((noreturn))用法
//标明函数无返回值
//用来修饰lcore_main函数，标明lcore_main无返回值
*/
/*
//1、检测CPU与网卡是否匹配
//2、建议使用本地CPU就近网卡？？？，不理解
//3、数据接收、发送的while(1)
*/
static __attribute__((noreturn)) void
lcore_main(void)
{
const uint8_t nb_ports = rte_eth_dev_count(); //网口总数
uint8_t port; //临时变量，网口号
/*
* Check that the port is on the same NUMA node as the polling thread
* for best performance.
* 检测CPU和网口是否匹配
* ？？？？，不理解，姑且看作是一个检测机制
*/
for (port = 0; port < nb_ports; port++) //遍历所有网口
if (rte_eth_dev_socket_id(port) > 0 && //检测的IF语句
rte_eth_dev_socket_id(port) !=
(int)rte_socket_id())
printf("WARNING, port %u is on remote NUMA node to "
"polling thread.\n\tPerformance will "
"not be optimal.\n", port);
printf("\nCore %u forwarding packets. [Ctrl+C to quit]\n",
rte_lcore_id());
/* Run until the application is quit or killed. */
/*运行 直到 应用程序 推出 或 被kill*/
for (;;) {
/*
* Receive packets on a port and forward them on the paired
* port. The mapping is 0 -> 1, 1 -> 0, 2 -> 3, 3 -> 2, etc.
* 从Eth接收数据包 ，并发送到 ETH上。
* 发送顺序为：0 的接收 到 1的 发送，
* 1 的接收 到 0的 发送
* 每两个端口为一对
*/
for (port = 0; port < nb_ports; port++) { //遍历所有网口
/* Get burst of RX packets, from first port of pair. */
struct rte_mbuf *bufs[BURST_SIZE];
//收包，接收到nb_tx个包
//端口，队列，收包队列，队列大小
const uint16_t nb_rx = rte_eth_rx_burst(port, 0,
bufs, BURST_SIZE);
if (unlikely(nb_rx == 0))
continue;
/* Send burst of TX packets, to second port of pair. */
//发包，发送nb_rx个包
//端口，队列，发送缓冲区，发包个数
const uint16_t nb_tx = rte_eth_tx_burst(port ^ 1, 0,
bufs, nb_rx);
//*****注意：以上流程为：从x收到的包，发送到x^1口
//其中，0^1 = 1, 1^1 = 0
//此运算可以达到测试要求的收、发包逻辑
/* Free any unsent packets. */
//释放不发送的数据包
//1、收到nb_rx个包，转发了nb_tx个，剩余nb_rx-nb_tx个
//2、把剩余的包释放掉
if (unlikely(nb_tx < nb_rx)) {
uint16_t buf;
for (buf = nb_tx; buf < nb_rx; buf++)
rte_pktmbuf_free(bufs[buf]); //释放包
}
}
}
}
/*
* The main function, which does initialization and calls the per-lcore
* functions.
*/
int
main(int argc, char *argv[])
{
struct rte_mempool *mbuf_pool; //指向内存池结构的指针变量
unsigned nb_ports; //网口个数
uint8_t portid; //网口号，临时的标记变量
/* Initialize the Environment Abstraction Layer (EAL). */
int ret = rte_eal_init(argc, argv); //初始化
if (ret < 0)
rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
argc -= ret; //??本操作莫名其妙,似乎一点用处也没有
argv += ret; //??本操作莫名其妙,似乎一点用处也没有
/* Check that there is an even number of ports to send/receive on. */
nb_ports = rte_eth_dev_count(); //获取当前有效网口的个数
if (nb_ports < 2 || (nb_ports & 1)) //如果有效网口数小于2或有效网口数为奇数0，则出错
rte_exit(EXIT_FAILURE, "Error: number of ports must be even\n");
/* Creates a new mempool in memory to hold the mbufs. */
/*创建一个新的内存池*/
//"MBUF_POOL"内存池名, NUM_MBUFS * nb_ports网口数,
// MBUF_CACHE_SIZE ??, 0, RTE_MBUF_DEFAULT_BUF_SIZE ??, rte_socket_id()??
//此函数为rte_mempoll_create()的封装
//此函数疑惑比较多，需要进一步看代码，先放着
mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL", NUM_MBUFS * nb_ports,
MBUF_CACHE_SIZE, 0, RTE_MBUF_DEFAULT_BUF_SIZE, rte_socket_id());
if (mbuf_pool == NULL)
rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");
//初始化所有的网口
/* Initialize all ports. */
for (portid = 0; portid < nb_ports; portid++) //遍历所有网口
if (port_init(portid, mbuf_pool) != 0) //初始化指定网口，需要网口号和内存池，此函数为自定义函数，看前面定义
rte_exit(EXIT_FAILURE, "Cannot init port %"PRIu8 "\n",
portid);
//如果逻辑核心总数>1 ,打印警告信息，此程序用不上多个逻辑核心
//逻辑核心可以通过传递参数 -c 逻辑核掩码来设置
if (rte_lcore_count() > 1)
printf("\nWARNING: Too many lcores enabled. Only 1 used.\n");
/* Call lcore_main on the master core only. */
//执行主函数
lcore_main();
return 0;
}
时间： 2024-11-09 12:34:24