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Linux 内核 TCP 套接字函数

tag-icon • tag-icon tcp linux-kernel sockets
Linux 内核 TCP 套接字函数

因此，我一直在查看 Linux 内核 v3.8.0-19-generic 源代码，我注意到 proto 结构体（其成员是用于套接字操作的虚拟函数，具体取决于所使用的特定协议和 tcp 的 proto 结构体）称为 tcp_prot，如下所示：

struct proto tcp_prot = {
    .name           = "TCP",
    .owner          = THIS_MODULE,
    .close          = tcp_close,
    .connect        = tcp_v4_connect,
    .disconnect     = tcp_disconnect,
    .accept         = inet_csk_accept,
    .ioctl          = tcp_ioctl,
    .init           = tcp_v4_init_sock,
    .destroy        = tcp_v4_destroy_sock,
    .shutdown       = tcp_shutdown,
    .setsockopt     = tcp_setsockopt,
    .getsockopt     = tcp_getsockopt,
    .recvmsg        = tcp_recvmsg,
    .sendmsg        = tcp_sendmsg,
    .sendpage       = tcp_sendpage,
    .backlog_rcv        = tcp_v4_do_rcv,
    .release_cb     = tcp_release_cb,
    .mtu_reduced        = tcp_v4_mtu_reduced,
    .hash           = inet_hash,
    .unhash         = inet_unhash,
    .get_port       = inet_csk_get_port,
    .enter_memory_pressure  = tcp_enter_memory_pressure,
    .sockets_allocated  = &tcp_sockets_allocated,
    .orphan_count       = &tcp_orphan_count,
    .memory_allocated   = &tcp_memory_allocated,
    .memory_pressure    = &tcp_memory_pressure,
    .sysctl_wmem        = sysctl_tcp_wmem,
    .sysctl_rmem        = sysctl_tcp_rmem,
    .max_header     = MAX_TCP_HEADER,
    .obj_size       = sizeof(struct tcp_sock),
    .slab_flags     = SLAB_DESTROY_BY_RCU,
    .twsk_prot      = &tcp_timewait_sock_ops,
    .rsk_prot       = &tcp_request_sock_ops,
    .h.hashinfo     = &tcp_hashinfo,
    .no_autobind        = true,
#ifdef CONFIG_COMPAT
    .compat_setsockopt  = compat_tcp_setsockopt,
    .compat_getsockopt  = compat_tcp_getsockopt,
#endif
#ifdef CONFIG_MEMCG_KMEM
    .init_cgroup        = tcp_init_cgroup,
    .destroy_cgroup     = tcp_destroy_cgroup,
    .proto_cgroup       = tcp_proto_cgroup,
#endif
};
EXPORT_SYMBOL(tcp_prot);

所以我注意到不此结构中为“bind()”函数添加了条目！SCTP 的 proto 结构定义为 sctp_prot，它有一个 find bind 函数列表（它与 sctp_bind 挂钩），但 tcp 套接字绑定函数在哪里？我之所以问这个问题，是因为事实上，GCC 套接字 API 中的绑定函数一直在给我的 TCP 套接字带来麻烦；而且纯粹是出于好奇。

答案1

一切都结束了net/ipv4/af_inet.c

const struct proto_ops inet_stream_ops = {
        .family            = PF_INET,
        .owner             = THIS_MODULE,
        .release           = inet_release,
        .bind              = inet_bind,      <---- here
        .connect           = inet_stream_connect,
        .socketpair        = sock_no_socketpair,
        .accept            = inet_accept,
        .getname           = inet_getname,
        .poll              = tcp_poll,
...

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