https://blog.csdn.net/pangyemeng/article/details/78281829
0x01 缘由
年初，学习了l3fwd的例子，进行三层转发，现在学习下特定转发，这个在虚拟化设备中常见，也是加强对dpdk的熟悉。
0x02 介绍
在虚拟化环境下的L3层转发应用是用DPDK处理数据包的一个简单例子。这个L3层转发应用充分发挥SR-IOV的特征。
这个应用演示如何使用hash和LPM DPDK库去实现数据包转发。这个转发策略是基于输入包的信息。
查询方法既有基于hash的也有基于LPM的，你如何选择在编译的时候决定。当所选择的查找方法是基于hash时，使用hash对象来模拟流分类阶段。 哈希对象与流表相关使用，以便在运行时将每个输入数据包映射到其流。
哈希查询键由DiffServ 5元组表示，它由从输入数据包读取的以下字段组成：源IP地址，目标IP地址，协议，源端口和目标端口。 从识别的流表条目读取输入数据包的输出接口的ID。应用程序使用的一组流在初始化时静态配置并加载到散列中。 当选择的查找方法是基于LPM时，使用LPM对象来模拟IPv4分组的转发阶段。 LPM对象用作路由表，用于在运行时识别每个输入数据包的下一跳。
LPM查找键由从输入数据包读取的目标IP地址字段表示。 输入数据包的输出接口的ID是LPM查询返回的下一跳。 应用程序使用的一组LPM规则在初始化时被静态配置并加载到LPM对象中。
0x03 运行环境
运行参数样板：
./build/l3fwd-vf [EAL options] -- -p PORTMASK --config(port,queue,lcore)[,(port,queue,lcore)]
参数解释：
[EAL options] EAL选项已经在其他例子中已有说明。
-p [端口掩码 -- 网卡掩码，在部署DPDK运行环境时绑定的网卡]： 十六进制表示
--config: 哪个网口哪个队列绑定到哪个逻辑核
–no-numa： 是否关闭对numa结构的识别
运行实例：
./l3fwd-vf -l 1,2 -n 4 -- -p 0x3 --config="(0,0,1),(1,0,2)"
-这个实例占用的逻辑核为1,2
-启动1、2号网卡
-端口映射关系为：
0号网卡0号队列映射到1号逻辑核上；
1号网卡0号队列映射到2号逻辑核上；
运行效果如下（添加了一些提示信息）：
LPM作为路由查询表：
<span style="font-size:18px;">Initializing port 0 ... Creating queues: nb_rxq=1 nb_txq=1... Address:A0:36:9F:03:A8:CA, Allocated mbuf pool on socket 0
LPM: Adding route 0x01010100 / 24 (0)
LPM: Adding route 0x02010100 / 24 (1)
LPM: Adding route 0x03010100 / 24 (2)
LPM: Adding route 0x04010100 / 24 (3)
LPM: Adding route 0x05010100 / 24 (4)
LPM: Adding route 0x06010100 / 24 (5)
LPM: Adding route 0x07010100 / 24 (6)
LPM: Adding route 0x08010100 / 24 (7)
txq=0,0,0 PMD: eth_igb_tx_queue_setup(): sw_ring=0x7ffc3814d2c0 hw_ring=0x7ffc3814f300 dma_addr=0x6734f300
Initializing port 1 ... Creating queues: nb_rxq=1 nb_txq=1... Address:A0:36:9F:03:A8:CB, txq=1,0,0 PMD: eth_igb_tx_queue_setup(): sw_ring=0x
7ffc3813b040 hw_ring=0x7ffc3813d080 dma_addr=0x6733d080
Initializing rx queues on lcore 1 ... rxq=0,0,0 PMD: eth_igb_rx_queue_setup(): sw_ring=0x7ffc3812aac0 hw_ring=0x7ffc3812af00 dma_addr=0x6732a
f00
Initializing rx queues on lcore 2 ... rxq=1,0,0 PMD: eth_igb_rx_queue_setup(): sw_ring=0x7ffc3811a540 hw_ring=0x7ffc3811a980 dma_addr=0x6731a
980
PMD: eth_igb_start(): <<
done: Port 0
PMD: eth_igb_start(): <<
done: Port 1
L3FWD: entering main loop on lcore 2
L3FWD: -- lcoreid=2 portid=1 rxqueueid=0
L3FWD: entering main loop on lcore 1
L3FWD: -- lcoreid=1 portid=0 rxqueueid=0</span>
Hash作为路由查询表：
<span style="font-size:18px;">Initializing port 0 ... Creating queues: nb_rxq=1 nb_txq=1... Address:A0:36:9F:03:A8:CA, Allocated mbuf pool on socket 0
Hash: Adding key
IP dst = 640a0001, IP src = c80a0001, port dst = 101, port src = 11, proto = 6
Hash: Adding key
IP dst = 64140002, IP src = c8140002, port dst = 102, port src = 12, proto = 6
Hash: Adding key
IP dst = 641e0003, IP src = c81e0003, port dst = 103, port src = 13, proto = 6
Hash: Adding key
IP dst = 64280004, IP src = c8280004, port dst = 104, port src = 14, proto = 6
txq=0,0,0 PMD: eth_igb_tx_queue_setup(): sw_ring=0x7fd48af7fcc0 hw_ring=0x7fd48af81d00 dma_addr=0x67381d00
Initializing port 1 ... Creating queues: nb_rxq=1 nb_txq=1... Address:A0:36:9F:03:A8:CB, txq=1,0,0 PMD: eth_igb_tx_queue_setup(): sw_ring=0x
7fd48af6da40 hw_ring=0x7fd48af6fa80 dma_addr=0x6736fa80
Initializing rx queues on lcore 1 ... rxq=0,0,0 PMD: eth_igb_rx_queue_setup(): sw_ring=0x7fd48af5d4c0 hw_ring=0x7fd48af5d900 dma_addr=0x6735d
900
Initializing rx queues on lcore 2 ... rxq=1,0,0 PMD: eth_igb_rx_queue_setup(): sw_ring=0x7fd48af4cf40 hw_ring=0x7fd48af4d380 dma_addr=0x6734d
380
PMD: eth_igb_start(): <<
done: Port 0
PMD: eth_igb_start(): <<
done: Port 1
L3FWD: entering main loop on lcore 2
L3FWD: -- lcoreid=2 portid=1 rxqueueid=0
L3FWD: entering main loop on lcore 1
L3FWD: -- lcoreid=1 portid=0 rxqueueid=0</span>
模拟发包去查询（添加一些实际输出）：
绑定两个网口0，1,连接到另一台服务器，另一台服务器抓包，分析数据包修改的情况，运行效果如下：
数据包分析：
0x04 整体源码分析
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <sys/types.h>
#include <string.h>
#include <sys/queue.h>
#include <stdarg.h>
#include <errno.h>
#include <getopt.h>
#include <signal.h>
#include <rte_common.h>
#include <rte_byteorder.h>
#include <rte_log.h>
#include <rte_memory.h>
#include <rte_memcpy.h>
#include <rte_memzone.h>
#include <rte_eal.h>
#include <rte_per_lcore.h>
#include <rte_launch.h>
#include <rte_atomic.h>
#include <rte_spinlock.h>
#include <rte_cycles.h>
#include <rte_prefetch.h>
#include <rte_lcore.h>
#include <rte_per_lcore.h>
#include <rte_branch_prediction.h>
#include <rte_interrupts.h>
#include <rte_pci.h>
#include <rte_random.h>
#include <rte_debug.h>
#include <rte_ether.h>
#include <rte_ethdev.h>
#include <rte_ring.h>
#include <rte_mempool.h>
#include <rte_mbuf.h>
#include <rte_ip.h>
#include <rte_tcp.h>
#include <rte_udp.h>
#include <rte_string_fns.h>
#define APP_LOOKUP_EXACT_MATCH 0 //精确匹配算法
#define APP_LOOKUP_LPM 1 //最长匹配算法
#define DO_RFC_1812_CHECKS //校验检查 如ip头的合法性
//#define APP_LOOKUP_METHOD APP_LOOKUP_EXACT_MATCH //使用何种查询表
#ifndef APP_LOOKUP_METHOD
#define APP_LOOKUP_METHOD APP_LOOKUP_LPM
#endif
/* 下面是一些相关头文件 */
#if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH)
#include <rte_hash.h>
#elif (APP_LOOKUP_METHOD == APP_LOOKUP_LPM)
#include <rte_lpm.h>
#else
#error "APP_LOOKUP_METHOD set to incorrect value"
#endif
#define RTE_LOGTYPE_L3FWD RTE_LOGTYPE_USER1
/* 内存池缓存大小 */
#define MEMPOOL_CACHE_SIZE 256
/*
* 该表达式用于根据用户输入计算所需的mbufs数，考虑到rx和tx硬件环的内存，每lcore的缓存和每个端口的mtable .
* RTE_MAX用于确保NB_MBUF不会低于最小值 8192。
*/
#define NB_MBUF RTE_MAX ( \
(nb_ports*nb_rx_queue*RTE_TEST_RX_DESC_DEFAULT + \
nb_ports*nb_lcores*MAX_PKT_BURST + \
nb_ports*n_tx_queue*RTE_TEST_TX_DESC_DEFAULT + \
nb_lcores*MEMPOOL_CACHE_SIZE), \
(unsigned)8192)
/*
*应优先设置RX和TX预取，主机和写回阈值以获得最佳性能。 请参阅网络控制器的数据表和支持DPDK文档，
*了解如何设置这些参数的指导。
*/
#define RX_PTHRESH 8 /**< Default values of RX prefetch threshold reg. */
#define RX_HTHRESH 8 /**< Default values of RX host threshold reg. */
#define RX_WTHRESH 4 /**< Default values of RX write-back threshold reg. */
/*
*这些默认值经过优化，可与Intel（R）82599 10 GbE控制器和DPDK ixgbe PMD配合使用。 考虑为其他网络控
*制器和/或网络驱动程序使用其他值。
*/
#define TX_PTHRESH 36 /**< Default values of TX prefetch threshold reg. */
#define TX_HTHRESH 0 /**< Default values of TX host threshold reg. */
#define TX_WTHRESH 0 /**< Default values of TX write-back threshold reg. */
#define MAX_PKT_BURST 32
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
#define NB_SOCKETS 8
#define SOCKET0 0
/* 在读取数据包时，配置预取数据包数。 */
#define PREFETCH_OFFSET 3
/*
* 可配置的RX / TX环形描述符数量。
*/
#define RTE_TEST_RX_DESC_DEFAULT 128
#define RTE_TEST_TX_DESC_DEFAULT 512
static uint16_t nb_rxd = RTE_TEST_RX_DESC_DEFAULT;
static uint16_t nb_txd = RTE_TEST_TX_DESC_DEFAULT;
/* 网口的地址 */
static struct ether_addr ports_eth_addr[RTE_MAX_ETHPORTS];
/* mask of enabled ports */
static uint32_t enabled_port_mask = 0;
static int numa_on = 1; /**< 默认启动numa特性 */
/* mbuf表*/
struct mbuf_table {
uint16_t len; //长度
struct rte_mbuf *m_table[MAX_PKT_BURST];//对应的rte_mbuf结构指针数组。
};
/* 与该逻辑核关联的网口和队列id */
struct lcore_rx_queue {
uint8_t port_id; //网口ID
uint8_t queue_id; //接收队列ID
} __rte_cache_aligned;
#define MAX_RX_QUEUE_PER_LCORE 16 //每个逻辑核最多有16个接收队列
#define MAX_TX_QUEUE_PER_PORT 1 //每个网口一个发送队列
#define MAX_RX_QUEUE_PER_PORT 1 //每个网口一个接受队列
#define MAX_LCORE_PARAMS 1024 //最多1024个lcore参数
struct lcore_params {
uint8_t port_id; //网口id
uint8_t queue_id; //队列id
uint8_t lcore_id; //逻辑核id
} __rte_cache_aligned;
static struct lcore_params lcore_params_array[MAX_LCORE_PARAMS]; //静态全局逻辑核参数
//当未配置时使用默认值
static struct lcore_params lcore_params_array_default[] = {
{0, 0, 2},
{0, 1, 2},
{0, 2, 2},
{1, 0, 2},
{1, 1, 2},
{1, 2, 2},
{2, 0, 2},
{3, 0, 3},
{3, 1, 3},
};
static struct lcore_params * lcore_params = lcore_params_array_default; //使用一个全局指针
//配置多少个参数
static uint16_t nb_lcore_params = sizeof(lcore_params_array_default) /
sizeof(lcore_params_array_default[0]);
//网口的一些属性设置，如模式，如巨型侦的处理。
static struct rte_eth_conf port_conf = {
.rxmode = {
.mq_mode = ETH_MQ_RX_RSS,
.max_rx_pkt_len = ETHER_MAX_LEN,
.split_hdr_size = 0,
.header_split = 0, /**< Header Split disabled */
.hw_ip_checksum = 1, /**< IP checksum offload enabled */
.hw_vlan_filter = 0, /**< VLAN filtering disabled */
.jumbo_frame = 0, /**< Jumbo Frame Support disabled */
.hw_strip_crc = 0, /**< CRC stripped by hardware */
},
.rx_adv_conf = {
.rss_conf = {
.rss_key = NULL,
.rss_hf = ETH_RSS_IP,
},
},
.txmode = {
.mq_mode = ETH_MQ_TX_NONE,
},
};
//内存池指针，对应物理CPU颗数。
static struct rte_mempool * pktmbuf_pool[NB_SOCKETS];
//下面是用hash的方式进行精确匹配
#if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH)
#ifdef RTE_MACHINE_CPUFLAG_SSE4_2
#include <rte_hash_crc.h>
#define DEFAULT_HASH_FUNC rte_hash_crc
#else
#include <rte_jhash.h>
#define DEFAULT_HASH_FUNC rte_jhash
#endif
//五元组
struct ipv4_5tuple {
uint32_t ip_dst; //目的IP地址
uint32_t ip_src; //源IP地址
uint16_t port_dst; //目的端口
uint16_t port_src; //源端口
uint8_t proto; //协议类型
} __attribute__((__packed__));
//三层转发路由
struct l3fwd_route {
struct ipv4_5tuple key; //五元组key
uint8_t if_out; //出口网口
};
//配置hash 路由参数
static struct l3fwd_route l3fwd_route_array[] = {
{{IPv4(100,10,0,1), IPv4(200,10,0,1), 101, 11, IPPROTO_TCP}, 0},
{{IPv4(100,20,0,2), IPv4(200,20,0,2), 102, 12, IPPROTO_TCP}, 1},
{{IPv4(100,30,0,3), IPv4(200,30,0,3), 103, 13, IPPROTO_TCP}, 2},
{{IPv4(100,40,0,4), IPv4(200,40,0,4), 104, 14, IPPROTO_TCP}, 3},
};
typedef struct rte_hash lookup_struct_t; //rte hash结构
static lookup_struct_t *l3fwd_lookup_struct[NB_SOCKETS]; //申请指针数组
#define L3FWD_HASH_ENTRIES 1024
//hash 参数
struct rte_hash_parameters l3fwd_hash_params = {
.name = "l3fwd_hash_0",
.entries = L3FWD_HASH_ENTRIES,
.key_len = sizeof(struct ipv4_5tuple),
.hash_func = DEFAULT_HASH_FUNC,
.hash_func_init_val = 0,
.socket_id = SOCKET0,
};
#define L3FWD_NUM_ROUTES \
(sizeof(l3fwd_route_array) / sizeof(l3fwd_route_array[0]))
static uint8_t l3fwd_out_if[L3FWD_HASH_ENTRIES] __rte_cache_aligned;
#endif
//LPM 相关结构和初始化
#if (APP_LOOKUP_METHOD == APP_LOOKUP_LPM)
//三层路由结构
struct l3fwd_route {
uint32_t ip; //ip
uint8_t depth; //深度
uint8_t if_out; //出口
};
//相关参数
static struct l3fwd_route l3fwd_route_array[] = {
{IPv4(1,1,1,0), 24, 0},
{IPv4(2,1,1,0), 24, 1},
{IPv4(3,1,1,0), 24, 2},
{IPv4(4,1,1,0), 24, 3},
{IPv4(5,1,1,0), 24, 4},
{IPv4(6,1,1,0), 24, 5},
{IPv4(7,1,1,0), 24, 6},
{IPv4(8,1,1,0), 24, 7},
};
//理由参数个数
#define L3FWD_NUM_ROUTES \
(sizeof(l3fwd_route_array) / sizeof(l3fwd_route_array[0]))
//规则个数
#define L3FWD_LPM_MAX_RULES 1024
typedef struct rte_lpm lookup_struct_t;
static lookup_struct_t *l3fwd_lookup_struct[NB_SOCKETS];
#endif
//逻辑核配置
struct lcore_conf {
uint16_t n_rx_queue; //接收队列个数
struct lcore_rx_queue rx_queue_list[MAX_RX_QUEUE_PER_LCORE]; //接收队列配置数组
uint16_t tx_queue_id; //发送队列id
struct mbuf_table tx_mbufs[RTE_MAX_ETHPORTS]; //数据包缓存
lookup_struct_t * lookup_struct; //查询结构
} __rte_cache_aligned;
static struct lcore_conf lcore_conf[RTE_MAX_LCORE]; //逻辑核参数
static rte_spinlock_t spinlock_conf[RTE_MAX_ETHPORTS] = {RTE_SPINLOCK_INITIALIZER}; //自旋锁，来保证对一个网口竞争访问；
/* 在一个发送网口发送数据包 */
static inline int
send_burst(struct lcore_conf *qconf, uint16_t n, uint8_t port)
{
struct rte_mbuf **m_table; //包结构表
int ret;
uint16_t queueid;
queueid = qconf->tx_queue_id;
m_table = (struct rte_mbuf **)qconf->tx_mbufs[port].m_table;
rte_spinlock_lock(&spinlock_conf[port]); //上锁（在这盘旋）
ret = rte_eth_tx_burst(port, queueid, m_table, n); //发送数据
rte_spinlock_unlock(&spinlock_conf[port]); //释放锁，其他线程可以访问
if (unlikely(ret < n)) {
do {
rte_pktmbuf_free(m_table[ret]); //释放结构
} while (++ret < n);
}
return 0;
}
/* 将一个包插入队列，当队列满时将数据发送。*/
static inline int
send_single_packet(struct rte_mbuf *m, uint8_t port)
{
uint32_t lcore_id;
uint16_t len;
struct lcore_conf *qconf;
lcore_id = rte_lcore_id(); //获取当前线程处于哪个逻辑核上
qconf = &lcore_conf[lcore_id]; //根据对应的逻辑核找对对应的配置
len = qconf->tx_mbufs[port].len; //此时发送队列中的包个数
qconf->tx_mbufs[port].m_table[len] = m; //将对应的数据放到对应的位置
len++; //包长度加1
/* 当队列数据包达到了MAX_PKT_BURST ，则立刻发送 */
if (unlikely(len == MAX_PKT_BURST)) {
send_burst(qconf, MAX_PKT_BURST, port); //发送对应的数据包
len = 0; //长度置0
}
qconf->tx_mbufs[port].len = len; //这个网口的发送队列置0
return 0;
}
#ifdef DO_RFC_1812_CHECKS
//此处做相关校验。
static inline int
is_valid_ipv4_pkt(struct ipv4_hdr *pkt, uint32_t link_len)
{
/* From http://www.rfc-editor.org/rfc/rfc1812.txt section 5.2.2 */
/*
* 1. The packet length reported by the Link Layer must be large
* enough to hold the minimum length legal IP datagram (20 bytes).
*/
if (link_len < sizeof(struct ipv4_hdr))
return -1;
/* 2. The IP checksum must be correct. */
/* this is checked in H/W */
/*
* 3. The IP version number must be 4. If the version number is not 4
* then the packet may be another version of IP, such as IPng or
* ST-II.
*/
if (((pkt->version_ihl) >> 4) != 4)
return -3;
/*
* 4. The IP header length field must be large enough to hold the
* minimum length legal IP datagram (20 bytes = 5 words).
*/
if ((pkt->version_ihl & 0xf) < 5)
return -4;
/*
* 5. The IP total length field must be large enough to hold the IP
* datagram header, whose length is specified in the IP header length
* field.
*/
if (rte_cpu_to_be_16(pkt->total_length) < sizeof(struct ipv4_hdr))
return -5;
return 0;
}
#endif
#if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH)
static void
print_key(struct ipv4_5tuple key)
{
//打印5元组
printf("IP dst = %08x, IP src = %08x, port dst = %d, port src = %d, proto = %d\n",
(unsigned)key.ip_dst, (unsigned)key.ip_src, key.port_dst, key.port_src, key.proto);
}
//得到转发网口
static inline uint8_t
get_dst_port(struct ipv4_hdr *ipv4_hdr, uint8_t portid, lookup_struct_t * l3fwd_lookup_struct)
{
struct ipv4_5tuple key; //五元组key
struct tcp_hdr *tcp; //tcp 头部结构
struct udp_hdr *udp; //udp 头部结构
int ret = 0;
//将整数值从大端模式转化到cpu序列
key.ip_dst = rte_be_to_cpu_32(ipv4_hdr->dst_addr);
key.ip_src = rte_be_to_cpu_32(ipv4_hdr->src_addr);
key.proto = ipv4_hdr->next_proto_id; //ip层下的协议号，如tcp/udp
switch (ipv4_hdr->next_proto_id) {
case IPPROTO_TCP:
tcp = (struct tcp_hdr *)((unsigned char *) ipv4_hdr +
sizeof(struct ipv4_hdr));
key.port_dst = rte_be_to_cpu_16(tcp->dst_port); //目的端口
key.port_src = rte_be_to_cpu_16(tcp->src_port); //源端口
break;
case IPPROTO_UDP:
udp = (struct udp_hdr *)((unsigned char *) ipv4_hdr +
sizeof(struct ipv4_hdr));
key.port_dst = rte_be_to_cpu_16(udp->dst_port);
key.port_src = rte_be_to_cpu_16(udp->src_port);
break;
default:
key.port_dst = 0;
key.port_src = 0;
}
/* 查找目的端口 */
ret = rte_hash_lookup(l3fwd_lookup_struct, (const void *)&key);
//找不到默认从输入队列出，找到就从l3fwd_out_if[ret]返回；
return (uint8_t)((ret < 0)? portid : l3fwd_out_if[ret]);
}
#endif
#if (APP_LOOKUP_METHOD == APP_LOOKUP_LPM)
static inline uint8_t
get_dst_port(struct ipv4_hdr *ipv4_hdr, uint8_t portid, lookup_struct_t * l3fwd_lookup_struct)
{
uint32_t next_hop;
//将目的地址传入进行查询下一条信息。
return (uint8_t) ((rte_lpm_lookup(l3fwd_lookup_struct,
rte_be_to_cpu_32(ipv4_hdr->dst_addr), &next_hop) == 0)?
next_hop : portid);
}
#endif
//三层转发
static inline void
l3fwd_simple_forward(struct rte_mbuf *m, uint8_t portid, lookup_struct_t * l3fwd_lookup_struct)
{
struct ether_hdr *eth_hdr; //以太网头结构
struct ipv4_hdr *ipv4_hdr; //IP头
void *tmp;
uint8_t dst_port;
//找到以太网头偏移地址
eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
//找到IP头偏移地址 偏移了sizeof(struct ether_hdr)位
ipv4_hdr = rte_pktmbuf_mtod_offset(m, struct ipv4_hdr *,
sizeof(struct ether_hdr));
#ifdef DO_RFC_1812_CHECKS
//做头部检查
/* Check to make sure the packet is valid (RFC1812) */
if (is_valid_ipv4_pkt(ipv4_hdr, m->pkt_len) < 0) {
rte_pktmbuf_free(m);
return;
}
#endif
//查找路由
dst_port = get_dst_port(ipv4_hdr, portid, l3fwd_lookup_struct);
if (dst_port >= RTE_MAX_ETHPORTS || (enabled_port_mask & 1 << dst_port) == 0)
dst_port = portid; //查出来的dst_port有问题，或者是未启动的port，则用默认的port
printf("forward to %d port\n", dst_port);
/* 02:00:00:00:00:xx ，修改目的mac地址*/
tmp = ð_hdr->d_addr.addr_bytes[0];
*((uint64_t *)tmp) = 0x000000000002 + ((uint64_t)dst_port << 40);
#ifdef DO_RFC_1812_CHECKS
/* Update time to live and header checksum */
--(ipv4_hdr->time_to_live); //更新TTL
++(ipv4_hdr->hdr_checksum);
#endif
/* src addr 复制源地址 */
ether_addr_copy(&ports_eth_addr[dst_port], ð_hdr->s_addr);
send_single_packet(m, dst_port);
}
/* main processing loop */
static int
main_loop(__attribute__((unused)) void *dummy)
{
//每个逻辑核都会有一个线程处理
struct rte_mbuf *pkts_burst[MAX_PKT_BURST]; //数据包发送缓存
unsigned lcore_id;
uint64_t prev_tsc, diff_tsc, cur_tsc;
int i, j, nb_rx;
uint8_t portid, queueid;
struct lcore_conf *qconf;
const uint64_t drain_tsc = (rte_get_tsc_hz() + US_PER_S - 1) / US_PER_S * BURST_TX_DRAIN_US;
prev_tsc = 0;
lcore_id = rte_lcore_id(); //获取逻辑核ID
qconf = &lcore_conf[lcore_id]; //逻辑核对应的配置，逻辑核可以找到自己处理那些端口，哪些队列等。
if (qconf->n_rx_queue == 0) {
//逻辑核为配置任何队列，说明没啥事干，退出
RTE_LOG(INFO, L3FWD, "lcore %u has nothing to do\n", lcore_id);
return 0;
}
RTE_LOG(INFO, L3FWD, "entering main loop on lcore %u\n", lcore_id);
for (i = 0; i < qconf->n_rx_queue; i++) {
portid = qconf->rx_queue_list[i].port_id; //对应的网卡
queueid = qconf->rx_queue_list[i].queue_id; //对应的接收队列id
RTE_LOG(INFO, L3FWD, " -- lcoreid=%u portid=%hhu rxqueueid=%hhu\n", lcore_id,
portid, queueid);
}
while (1) {
//计时
cur_tsc = rte_rdtsc();
/*
* 发送数据包
*/
diff_tsc = cur_tsc - prev_tsc;
if (unlikely(diff_tsc > drain_tsc)) {
/*
* This could be optimized (use queueid instead of
* portid), but it is not called so often
*/
for (portid = 0; portid < RTE_MAX_ETHPORTS; portid++) {
//每个网口就一个发送队列
if (qconf->tx_mbufs[portid].len == 0)
continue;
//发送数据包
send_burst(&lcore_conf[lcore_id],
qconf->tx_mbufs[portid].len,
portid);
qconf->tx_mbufs[portid].len = 0;
}
prev_tsc = cur_tsc;
}
/*
* 从RX queues 读取数据包
*/
for (i = 0; i < qconf->n_rx_queue; ++i) {
portid = qconf->rx_queue_list[i].port_id; //端口
queueid = qconf->rx_queue_list[i].queue_id; //队列id
nb_rx = rte_eth_rx_burst(portid, queueid, pkts_burst, MAX_PKT_BURST);
/* 第一次逾期数据包 */
for (j = 0; j < PREFETCH_OFFSET && j < nb_rx; j++) {
rte_prefetch0(rte_pktmbuf_mtod(
pkts_burst[j], void *));
}
/* 预取并转发已经预取的数据包 */
for (j = 0; j < (nb_rx - PREFETCH_OFFSET); j++) {
rte_prefetch0(rte_pktmbuf_mtod(pkts_burst[
j + PREFETCH_OFFSET], void *));
l3fwd_simple_forward(pkts_burst[j], portid, qconf->lookup_struct);
}
/* 转发剩余的数据包 */
for (; j < nb_rx; j++) {
l3fwd_simple_forward(pkts_burst[j], portid, qconf->lookup_struct);
}
}
}
}
//检查逻辑核相关参数
static int
check_lcore_params(void)
{
uint8_t queue, lcore;
uint16_t i;
int socketid;
for (i = 0; i < nb_lcore_params; ++i) {
//队列是否在范围内
queue = lcore_params[i].queue_id;
if (queue >= MAX_RX_QUEUE_PER_PORT) {
printf("invalid queue number: %hhu\n", queue);
return -1;
}
//逻辑核是否在启动参数中指定
lcore = lcore_params[i].lcore_id;
if (!rte_lcore_is_enabled(lcore)) {
printf("error: lcore %hhu is not enabled in lcore mask\n", lcore);
return -1;
}
//numa结构
if ((socketid = rte_lcore_to_socket_id(lcore) != 0) &&
(numa_on == 0)) {
printf("warning: lcore %hhu is on socket %d with numa off \n",
lcore, socketid);
}
}
return 0;
}
//检查网口配置
static int
check_port_config(const unsigned nb_ports)
{
unsigned portid;
uint16_t i;
for (i = 0; i < nb_lcore_params; ++i) {
//是否在运行参数中指定
portid = lcore_params[i].port_id;
if ((enabled_port_mask & (1 << portid)) == 0) {
printf("port %u is not enabled in port mask\n", portid);
return -1;
}
if (portid >= nb_ports) {
printf("port %u is not present on the board\n", portid);
return -1;
}
}
return 0;
}
//得到网口的接收队列数
static uint8_t
get_port_n_rx_queues(const uint8_t port)
{
int queue = -1;
uint16_t i;
for (i = 0; i < nb_lcore_params; ++i) {
if (lcore_params[i].port_id == port && lcore_params[i].queue_id > queue)
queue = lcore_params[i].queue_id;
}
return (uint8_t)(++queue);
}
//初始化接收队列逻辑核配置结构
static int
init_lcore_rx_queues(void)
{
uint16_t i, nb_rx_queue;
uint8_t lcore;
for (i = 0; i < nb_lcore_params; ++i) {
lcore = lcore_params[i].lcore_id; //逻辑核ID
nb_rx_queue = lcore_conf[lcore].n_rx_queue; //此逻辑核队列数
if (nb_rx_queue >= MAX_RX_QUEUE_PER_LCORE) { //检查合法性
printf("error: too many queues (%u) for lcore: %u\n",
(unsigned)nb_rx_queue + 1, (unsigned)lcore);
return -1;
} else {
lcore_conf[lcore].rx_queue_list[nb_rx_queue].port_id =
lcore_params[i].port_id; //
lcore_conf[lcore].rx_queue_list[nb_rx_queue].queue_id =
lcore_params[i].queue_id;
lcore_conf[lcore].n_rx_queue++;
}
}
return 0;
}
/* display usage */
static void
print_usage(const char *prgname)
{
printf ("%s [EAL options] -- -p PORTMASK"
" [--config (port,queue,lcore)[,(port,queue,lcore]]\n"
" -p PORTMASK: hexadecimal bitmask of ports to configure\n"
" --config (port,queue,lcore): rx queues configuration\n"
" --no-numa: optional, disable numa awareness\n",
prgname);
}
/* 捕获从终端获取的信号，进行善后处理。*/
static void
signal_handler(int signum)
{
uint8_t portid;
uint8_t nb_ports = rte_eth_dev_count();
/* When we receive a SIGINT signal */
if (signum == SIGINT) {
for (portid = 0; portid < nb_ports; portid++) {
/* skip ports that are not enabled 检查哪些网卡启动 */
if ((enabled_port_mask & (1 << portid)) == 0)
continue;
rte_eth_dev_close(portid); //关闭相关网卡
}
}
rte_exit(EXIT_SUCCESS, "\n User forced exit\n");
}
//处理网口掩码
static int
parse_portmask(const char *portmask)
{
char *end = NULL;
unsigned long pm;
/* parse hexadecimal string */
pm = strtoul(portmask, &end, 16);
/*strtoul()会将参数nptr字符串根据参数base来转换成无符号的长整型数。
参数base范围从2至36，或0。参数base代表采用的进制方式，如base值为10
则采用10进制，若base值为16则采用16进制数等。*/
if ((portmask[0] == '\0') || (end == NULL) || (*end != '\0'))
return -1;
if (pm == 0)
return -1;
return pm;
}
//解析--config这个参数
static int
parse_config(const char *q_arg)
{
char s[256];
const char *p, *p0 = q_arg;
char *end;
enum fieldnames {
FLD_PORT = 0,
FLD_QUEUE,
FLD_LCORE,
_NUM_FLD
};
unsigned long int_fld[_NUM_FLD];
char *str_fld[_NUM_FLD];
int i;
unsigned size;
nb_lcore_params = 0;
while ((p = strchr(p0,'(')) != NULL) {
++p;
if((p0 = strchr(p,')')) == NULL)
return -1;
size = p0 - p;
if(size >= sizeof(s))
return -1;
snprintf(s, sizeof(s), "%.*s", size, p);
if (rte_strsplit(s, sizeof(s), str_fld, _NUM_FLD, ',') != _NUM_FLD)
return -1;
for (i = 0; i < _NUM_FLD; i++){
errno = 0;
int_fld[i] = strtoul(str_fld[i], &end, 0);
if (errno != 0 || end == str_fld[i] || int_fld[i] > 255)
return -1;
}
if (nb_lcore_params >= MAX_LCORE_PARAMS) {
printf("exceeded max number of lcore params: %hu\n",
nb_lcore_params);
return -1;
}
lcore_params_array[nb_lcore_params].port_id = (uint8_t)int_fld[FLD_PORT];
lcore_params_array[nb_lcore_params].queue_id = (uint8_t)int_fld[FLD_QUEUE];
lcore_params_array[nb_lcore_params].lcore_id = (uint8_t)int_fld[FLD_LCORE];
++nb_lcore_params;
}
lcore_params = lcore_params_array;
return 0;
}
/* Parse the argument given in the command line of the application */
static int
parse_args(int argc, char **argv)
{
int opt, ret;
char **argvopt;
int option_index;
char *prgname = argv[0];
static struct option lgopts[] = {
{"config", 1, 0, 0},
{"no-numa", 0, 0, 0},
{NULL, 0, 0, 0}
};
argvopt = argv;
while ((opt = getopt_long(argc, argvopt, "p:",
lgopts, &option_index)) != EOF) {
switch (opt) {
/* portmask */
case 'p':
enabled_port_mask = parse_portmask(optarg);
if (enabled_port_mask == 0) {
printf("invalid portmask\n");
print_usage(prgname);
return -1;
}
break;
/* long options */
case 0:
if (!strcmp(lgopts[option_index].name, "config")) {
ret = parse_config(optarg);
if (ret) {
printf("invalid config\n");
print_usage(prgname);
return -1;
}
}
if (!strcmp(lgopts[option_index].name, "no-numa")) {
printf("numa is disabled \n");
numa_on = 0;
}
break;
default:
print_usage(prgname);
return -1;
}
}
if (optind >= 0)
argv[optind-1] = prgname;
ret = optind-1;
optind = 0; /* reset getopt lib */
return ret;
}
//打印mac地址
static void
print_ethaddr(const char *name, const struct ether_addr *eth_addr)
{
char buf[ETHER_ADDR_FMT_SIZE];
ether_format_addr(buf, ETHER_ADDR_FMT_SIZE, eth_addr);
printf("%s%s", name, buf);
}
#if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH)
//构建hash表
static void
setup_hash(int socketid)
{
unsigned i;
int ret;
char s[64];
/* create hashes */
snprintf(s, sizeof(s), "l3fwd_hash_%d", socketid);
l3fwd_hash_params.name = s; //hash表名称
l3fwd_hash_params.socket_id = socketid; //对应的物理cpu id
l3fwd_lookup_struct[socketid] = rte_hash_create(&l3fwd_hash_params); //创建相关结构
if (l3fwd_lookup_struct[socketid] == NULL)
rte_exit(EXIT_FAILURE, "Unable to create the l3fwd hash on "
"socket %d\n", socketid);
/* 根据配置添加key,计算hash值 */
for (i = 0; i < L3FWD_NUM_ROUTES; i++) {
ret = rte_hash_add_key (l3fwd_lookup_struct[socketid],
(void *) &l3fwd_route_array[i].key);
if (ret < 0) {
rte_exit(EXIT_FAILURE, "Unable to add entry %u to the"
"l3fwd hash on socket %d\n", i, socketid);
}
l3fwd_out_if[ret] = l3fwd_route_array[i].if_out; //每个hash条目对应的输入网口
printf("Hash: Adding key\n");
print_key(l3fwd_route_array[i].key);
}
}
#endif
#if (APP_LOOKUP_METHOD == APP_LOOKUP_LPM)
//最长匹配算法
static void
setup_lpm(int socketid)
{
unsigned i;
int ret;
char s[64];
struct rte_lpm_config lpm_ipv4_config;
lpm_ipv4_config.max_rules = L3FWD_LPM_MAX_RULES;
lpm_ipv4_config.number_tbl8s = 256;
lpm_ipv4_config.flags = 0;
/* create the LPM table */
snprintf(s, sizeof(s), "L3FWD_LPM_%d", socketid);
l3fwd_lookup_struct[socketid] =
rte_lpm_create(s, socketid, &lpm_ipv4_config);
if (l3fwd_lookup_struct[socketid] == NULL)
rte_exit(EXIT_FAILURE, "Unable to create the l3fwd LPM table"
" on socket %d\n", socketid);
/* populate the LPM table */
for (i = 0; i < L3FWD_NUM_ROUTES; i++) {
ret = rte_lpm_add(l3fwd_lookup_struct[socketid],
l3fwd_route_array[i].ip,
l3fwd_route_array[i].depth,
l3fwd_route_array[i].if_out);
if (ret < 0) {
rte_exit(EXIT_FAILURE, "Unable to add entry %u to the "
"l3fwd LPM table on socket %d\n",
i, socketid);
}
printf("LPM: Adding route 0x%08x / %d (%d)\n",
(unsigned)l3fwd_route_array[i].ip,
l3fwd_route_array[i].depth,
l3fwd_route_array[i].if_out);
}
}
#endif
//初始化相关内存结构
static int
init_mem(unsigned nb_mbuf)
{
struct lcore_conf *qconf;
int socketid;
unsigned lcore_id;
char s[64];
for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
if (rte_lcore_is_enabled(lcore_id) == 0)
continue;
//numa结构
if (numa_on)
socketid = rte_lcore_to_socket_id(lcore_id);
else
socketid = 0;
if (socketid >= NB_SOCKETS) {
rte_exit(EXIT_FAILURE, "Socket %d of lcore %u is out of range %d\n",
socketid, lcore_id, NB_SOCKETS);
}
if (pktmbuf_pool[socketid] == NULL) {
//创建内存池
snprintf(s, sizeof(s), "mbuf_pool_%d", socketid);
pktmbuf_pool[socketid] = rte_pktmbuf_pool_create(s,
nb_mbuf, MEMPOOL_CACHE_SIZE, 0,
RTE_MBUF_DEFAULT_BUF_SIZE, socketid);
if (pktmbuf_pool[socketid] == NULL)
rte_exit(EXIT_FAILURE, "Cannot init mbuf pool on socket %d\n", socketid);
else
printf("Allocated mbuf pool on socket %d\n", socketid);
#if (APP_LOOKUP_METHOD == APP_LOOKUP_LPM)
setup_lpm(socketid);
#else
setup_hash(socketid);
#endif
}
qconf = &lcore_conf[lcore_id];
qconf->lookup_struct = l3fwd_lookup_struct[socketid];
}
return 0;
}
int
main(int argc, char **argv)
{
struct lcore_conf *qconf;
struct rte_eth_dev_info dev_info;
struct rte_eth_txconf *txconf;
int ret;
unsigned nb_ports;
uint16_t queueid;
unsigned lcore_id;
uint32_t nb_lcores;
uint16_t n_tx_queue;
uint8_t portid, nb_rx_queue, queue, socketid;
//处理信号
signal(SIGINT, signal_handler);
/* init EAL */
ret = rte_eal_init(argc, argv);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Invalid EAL parameters\n");
argc -= ret;
argv += ret;
/* parse application arguments (after the EAL ones) */
ret = parse_args(argc, argv);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Invalid L3FWD-VF parameters\n");
if (check_lcore_params() < 0)
rte_exit(EXIT_FAILURE, "check_lcore_params failed\n");
ret = init_lcore_rx_queues();
if (ret < 0)
rte_exit(EXIT_FAILURE, "init_lcore_rx_queues failed\n");
nb_ports = rte_eth_dev_count();
if (nb_ports > RTE_MAX_ETHPORTS)
nb_ports = RTE_MAX_ETHPORTS;
if (check_port_config(nb_ports) < 0)
rte_exit(EXIT_FAILURE, "check_port_config failed\n");
nb_lcores = rte_lcore_count();
/* initialize all ports */
for (portid = 0; portid < nb_ports; portid++) {
/* skip ports that are not enabled */
if ((enabled_port_mask & (1 << portid)) == 0) {
printf("\nSkipping disabled port %d\n", portid);
continue;
}
/* init port */
printf("Initializing port %d ... ", portid );
fflush(stdout);
/* must always equal(=1) */
nb_rx_queue = get_port_n_rx_queues(portid);
n_tx_queue = MAX_TX_QUEUE_PER_PORT;
printf("Creating queues: nb_rxq=%d nb_txq=%u... ",
nb_rx_queue, (unsigned)1 );
//队列配置
ret = rte_eth_dev_configure(portid, nb_rx_queue, n_tx_queue, &port_conf);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Cannot configure device: err=%d, port=%d\n",
ret, portid);
rte_eth_macaddr_get(portid, &ports_eth_addr[portid]);
print_ethaddr(" Address:", &ports_eth_addr[portid]);
printf(", ");
ret = init_mem(NB_MBUF);
if (ret < 0)
rte_exit(EXIT_FAILURE, "init_mem failed\n");
/* init one TX queue */
socketid = (uint8_t)rte_lcore_to_socket_id(rte_get_master_lcore());
printf("txq=%d,%d,%d ", portid, 0, socketid);
fflush(stdout);
rte_eth_dev_info_get(portid, &dev_info);
txconf = &dev_info.default_txconf;
if (port_conf.rxmode.jumbo_frame)
txconf->txq_flags = 0;
//发送队列配置
ret = rte_eth_tx_queue_setup(portid, 0, nb_txd,
socketid, txconf);
if (ret < 0)
rte_exit(EXIT_FAILURE, "rte_eth_tx_queue_setup: err=%d, "
"port=%d\n", ret, portid);
printf("\n");
}
for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
if (rte_lcore_is_enabled(lcore_id) == 0)
continue;
qconf = &lcore_conf[lcore_id];
qconf->tx_queue_id = 0;
printf("\nInitializing rx queues on lcore %u ... ", lcore_id );
fflush(stdout);
/* init RX queues */
for(queue = 0; queue < qconf->n_rx_queue; ++queue) {
portid = qconf->rx_queue_list[queue].port_id;
queueid = qconf->rx_queue_list[queue].queue_id;
if (numa_on)
socketid = (uint8_t)rte_lcore_to_socket_id(lcore_id);
else
socketid = 0;
printf("rxq=%d,%d,%d ", portid, queueid, socketid);
fflush(stdout);
//接收队列初始化
ret = rte_eth_rx_queue_setup(portid, queueid, nb_rxd,
socketid, NULL,
pktmbuf_pool[socketid]);
if (ret < 0)
rte_exit(EXIT_FAILURE, "rte_eth_rx_queue_setup: err=%d,"
"port=%d\n", ret, portid);
}
}
printf("\n");
/* start ports */
for (portid = 0; portid < nb_ports; portid++) {
if ((enabled_port_mask & (1 << portid)) == 0) {
continue;
}
/* Start device，开启设备 */
ret = rte_eth_dev_start(portid);
if (ret < 0)
rte_exit(EXIT_FAILURE, "rte_eth_dev_start: err=%d, port=%d\n",
ret, portid);
printf("done: Port %d\n", portid);
}
/* launch per-lcore init on every lcore */
rte_eal_mp_remote_launch(main_loop, NULL, CALL_MASTER);
RTE_LCORE_FOREACH_SLAVE(lcore_id) {
if (rte_eal_wait_lcore(lcore_id) < 0)
return -1;
}
return 0;
}
0x05 总结
遇到一个问题，发现这个程序无法处理TCP的数据包，看后期慢慢熟悉能否解决这个问题。