linux 网络数据接收流程

free

17

DMA

cacheRX FIFO

socket

+ sk : struct sock*

dma_map_single

used

__netif_receive_skb

3

net_rx_action

disable IRQ

inet_recvmsg

10

14

NIC driver

DDR

napi_gro_receive

RDT

__do_softirq

buf

read

11

8

__skb_queue_tail

e1000_probe

process_backlog

wenfh2020.comLinux 5.0.1

skb_put_data

e1000_receive_skb

IRQ

12

tcp_v4_rcv

e1000_irq_enable

napi_struct

5

struct e1000_rx_desc {    __le64 buffer_addr; /* Address of the descriptor's data buffer */    __le16 length;      /* Length of data DMAed into data buffer */    __le16 csum;        /* Packet checksum */    u8 status;          /* Descriptor status */    u8 errors;          /* Descriptor Errors */    __le16 special;};

ring buffer

e1000_adapter

+ napi : struct napi_struct

010101011010101...

vfs_read

16

7

napi_poll

2

sock

+ sk_receive_queue : struct sk_buff_head

9

ip_rcv

sk_buff

dma_sync_single_for_cpu

drop

APPLICATION LAYER

6

__napi_schedule

1

softnet_data

+ poll_list : struct list_head+ process_queue : struct sk_buff_head+ input_pkt_queue : struct sk_buff_head+ backlog : struct napi_struct

RDH

e1000_alloc_rx_buffers

DATALINK / PHYSICAL LAYER

e1000_copybreak

tcp_recvmsg

e1000_clean

wakeup

rps

e1000_intr

13

dma_alloc_coherent

__raise_softirq_irqoff(NET_RX_SOFTIRQ)

NETWORK / TRANSPORT LAYER

e1000_clean_rx_irq

Y

CPU

4

tcp_data_ready

enqueue_to_backlog

qlen > netdev_max_backlog

15

N

NIC

e1000_open