TCP/IP socket.c

最新推荐文章于 2023-11-18 11:25:07 发布

最新推荐文章于 2023-11-18 11:25:07 发布 · 90 阅读

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#网络

本文深入解析了Linux Socket编程的关键概念和技术细节，包括socket结构、地址结构、协议注册过程及socket创建流程等。通过分析核心代码，揭示了网络编程在Linux内核中的实现机制。

linux/net/socket.c

1. pops is inited in the sock_register() function, and sock_register is called in inet_proto_init/ipx_proto_init, and inet_proto_init/ipx_proto_init is used to initialize the global protocol table.

/*
* The protocol list. Each protocol is registered in here.
*/
static struct proto_ops *pops[NPROTO];

/*
* Protocol Table
*/
struct net_proto protocols[] = {
#ifdef CONFIG_IPX
{ "IPX", ipx_proto_init },

#endif

...

}

and the protocols init is like following,

void proto_init(void)
{
extern struct net_proto protocols[]; /* Network protocols */
struct net_proto *pro;

/* Kick all configured protocols. */
pro = protocols;
while (pro->name != NULL)
{
(*pro->init_func)(pro);
pro++;
}
/* We're all done... */
}

and start_kernel -> sock_init -> proto_init

2. definition of sockaddr

struct sockaddr {
unsigned short sa_family; /* address family, AF_xxx */
char sa_data[14]; /* 14 bytes of protocol address */
};

3. __asm__ and __volatile__ 内嵌汇编用法

例如： # define barrier() _asm__volatile_("": : :"memory")

refer to : http://www.dzsc.com/data/html/2009-5-31/76505.html

4. the struct of socket is below,

/*
* Internal representation of a socket. not all the fields are used by
* all configurations:
*
* server client
* conn client connected to server connected to
* iconn list of clients -unused-
* awaiting connections
* wait sleep for clients, sleep for connection,
* sleep for i/o sleep for i/o
*/
struct socket {
short type; /* SOCK_STREAM, ... */
socket_state state;
long flags;
struct proto_ops *ops; /* protocols do most everything */
void *data; /* protocol data */
struct socket *conn; /* server socket connected to */
struct socket *iconn; /* incomplete client conn.s */
struct socket *next;
struct wait_queue **wait; /* ptr to place to wait on */
struct inode *inode;
struct fasync_struct *fasync_list; /* Asynchronous wake up list */
};