本文主要记录Linux协议栈相关的主要系统调用的一些主要的函数调用栈，备忘。目前添加socket/connect
1.sys_socket
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bsd socket layer
=> sys_create net/socket.c
=> socket_create net/socket.c
=> __socket_create net/socket.c
=> sock_alloc net/socket.c
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inet sock layer
=> net_families[family]->create net/socket.c
=> inet_create net/ipv4/af_inet.c
=> list_for_each_entry_rcu(answer, &inetsw[sock->type], list)
=> sock->ops = answer->ops //绑定每个协议族的proto_ops到socket结构上，proto_ops通常是与下层传输层的接口比如inet_connect,inet_*
=> sk_alloc(net, PF_INET, GFP_KERNEL, answer->prot) net/core/sock.c
=> sk_prot_alloc net/core/sock.c
=> kmem_cache_alloc(prot->slab) net/core/sock.c
=> sk->sk_prot = prot; sk->family = family net/core/sock.c
=> sock_init_data net/core/sock.c
=> skb_queue_head_init(&sk->sk_receive_queue) net/core/sock.c
skb_queue_head_init(&sk->sk_write_queue)
skb_queue_head_init(&sk->sk_error_queue)=> sk->sk_state = TCP_CLOSE
sk_set_socket(sk, sock)=> sk->sk_prot->init(sk)
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transport layer
=> tcp_v4_init_sock net/ipv4/tcp_ipv4.c
=> tcp_init_sock net/ipv4/tcp.c
=> icsk->icsk_af_ops = &ipv4_specific net/ipv4/tcp_ipv4.c //这里挂接传输层的读写处理，每个sock结构有一个inet_connection_sock的队列负责接收对端的socket
2.connect
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bsd socket layer
=> sys_connect net/socket.c
=> sock->ops->connect(sock->proto_ops->connect) net/socket.c
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inet sock layer
=> inet_stream_ops->connect net/ipv4/af_inet.c
=> inet_stream_connect net/ipv4/af_inet.c
=> __inet_stream_connect net/ipv4/af_inet.c
=> sock->sk->sk_prot->connect net/ipv4/af_inet.c
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transport layer
=> tcp_prot->connect(tcp_v4_connect) net/ipv4/tcp_ipv4.c
=> ip_route_connect net/ipv4/tcp_ipv4.c
=> ip_route_connect_init include/net/route.h
=> flowi4_init_output include/net/flow.h
=> tcp_set_state(sk, TCP_SYN_SENT) net/ipv4/tcp_ipv4.c
=> tcp_connect net/ipv4/tcp_output.c
=> tcp_connect_init net/ipv4/tcp_output.c
=> sk_stream_alloc_skb net/ipv4/tcp.c
=> __alloc_skb net/core/skbuff.c
=> kmem_cache_alloc_node
=> tcp_connect_queue_skb net/ipv4/tcp_output.c
=> __tcp_add_write_queue_tail include/net/tcp.h
=> tcp_transmit_skb net/ipv4/tcp_output.c
=> icsk->icsk_af_ops->queue_xmit
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ip layer
=> ip_queue_xmit net/ipv4/ip_output.c
=> ip_route_output_ports net/ipv4/ip_output.c 路由
=> ip_local_out include/net/ip.h
=> ip_local_out_sk net/ipv4/ip_output.c
=> __ip_local_out net/ipv4/ip_output.c netfilter检查
=> nf_hook (netfilter hooks) include/linux/netfilter.h
=> nf_hook_thresh include/linux/netfilter.h
=> nf_hook_slow include/linux/netfilter.h
=> nf_iterate net/netfilter/core.c
=> dst_output_sk include/net/dst.h
=> dst_entry->output include/net/dst.h
=> ip_output? net/ipv4/ip_output.c
=> ip_finish_output net/ipv4/ip_output.c
=> ip_fragment net/ipv4/ip_output.c
=> ip_finish_output2 net/ipv4/ip_output.c
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hardware related layer
=> dst_neigh_output include/net/dst.h
=> neigh_hh_output include/net/neighbour.h
=> dev_queue_xmit net/core/dev.c
=> __dev_queue_xmit net/core/dev.c
=> netdev_pick_tx net/core/flow_dissector.c
=> __dev_xmit_skb net/core/dev.c
=> q->enqueue
=> __qdisc_run(q) net/sched/sch_generic.c
=> qdisc_restart net/sched/sch_generic.c
=> dequeue_skb net/sched/sch_generic.c
=> skb_get_tx_queue net/sched/sch_generic.c
=> netdev_get_tx_queue net/sched/sch_generic.c
=> sch_direct_xmit net/sched/sch_generic.c
=> validate_xmit_skb_list net/sched/sch_generic.c
=> dev_hard_start_xmit net/core/dev.c
=> xmit_one net/core/dev.c
=> netdev_start_xmit include/linux/netdevice.h
=> net_device_ops->ndo_start_xmit include/linux/netdevice.h
=> driver layer?
ref:
1. linux-3.19.3 src
2. Linux IP Networking A Guide to the Implementation and Modification of the Linux Protocol Stack
