kernel socket

socket流程
(af_inet udp)

 

数据结构

struct socket;

struct sock;

socket创建

socket() 

sys_socket()  --> kernel, socket.c

sock_create()

pf->create()  --> net_families,sock_register(),Create a packet,struct sock.

socket接收

应用层调用recvfrom()

sys_recvfrom()

sock_recvmsg()

__sock_recvmsg()

sock->ops->recvmsg() --> 在socket被创建时赋值inet_dgram_ops.

sock_common_recvmsg()

sk->sk_prot->recvmsg() --> sk_prot在sk_alloc()中被赋值为udp_prot.

udp_recvmsg()

skb_recv_datagram() --> 检查等待sk->sk_receive_queue中的数据

自下而上往sk_receive_queue中填充数据

...... 这里省略

udp_rcv()

__udp4_lib_rcv()

__udp4_lib_lookup() --> 查找到对应的sock

udp_queue_rcv_skb()

sock_queue_rcv_skb() --> jump to sock.c

skb_queue_tail() --> add to sk->sk_receive_queue

socket发送

sys_sendto()

sock_sendmsg()

__sock_sendmsg()

sock->ops->sendmsg()

inet_sendmsg()

sk->sk_prot->sendmsg()

udp_sendmsg()

ip_route_output_flow() --> 交给路由，之后省略