socket实现分析series(5)

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Linux Version：2.6.33

提示：本文是关于linux 如何实现socket 通信的介绍！

 

ipv4网络在内核初始化时进行来一些设置，以后对socket操作都跟这些设置有关，

先来看看inet的初始化过程

static int __init inet_init(void) {
    struct sk_buff *dummy_skb;
    struct inet_protosw *q;
    struct list_head *r;
    int rc = -EINVAL;

    BUILD_BUG_ON(sizeof(struct inet_skb_parm) > sizeof(dummy_skb->cb));

    rc = proto_register(&tcp_prot, 1);
    if (rc) goto out;

    rc = proto_register(&udp_prot, 1);
    if (rc) goto out_unregister_tcp_proto;

    rc = proto_register(&raw_prot, 1);
    if (rc) goto out_unregister_udp_proto;

    /* Tell SOCKET that we are alive... */
    (void)sock_register(&inet_family_ops);

#ifdef CONFIG_SYSCTL
    ip_static_sysctl_init();
#endif

    /* Add all the base protocols. */

    if (inet_add_protocol(&icmp_protocol, IPPROTO_ICMP) < 0)
        printk(KERN_CRIT "inet_init: Cannot add ICMP protocol\n");
    if (inet_add_protocol(&udp_protocol, IPPROTO_UDP) < 0)
        printk(KERN_CRIT "inet_init: Cannot add UDP protocol\n");
    if (inet_add_protocol(&tcp_protocol, IPPROTO_TCP) < 0)
        printk(KERN_CRIT "inet_init: Cannot add TCP protocol\n");
#ifdef CONFIG_IP_MULTICAST
    if (inet_add_protocol(&igmp_protocol, IPPROTO_IGMP) < 0)
        printk(KERN_CRIT "inet_init: Cannot add IGMP protocol\n");
#endif

    /* Register the socket-side information for inet_create. */
    for (r = &inetsw[0]; r < &inetsw[SOCK_MAX]; ++r)
        INIT_LIST_HEAD(r);

    for (q = inetsw_array; q < &inetsw_array[INETSW_ARRAY_LEN]; ++q)
        inet_register_protosw(q);

    /* Set the ARP module up */
    arp_init();

    /* Set the IP module up */
    ip_init();

    tcp_v4_init();

    /* Setup TCP slab cache for open requests. */
    tcp_init();

    /* Setup UDP memory threshold */
    udp_init();

    /* Add UDP-Lite (RFC 3828) */
    udplite4_register();

    /* Set the ICMP layer up */

    if (icmp_init() < 0)
        panic("Failed to create the ICMP control socket.\n");

    /* Initialise the multicast router */
#if defined(CONFIG_IP_MROUTE)
    if (ip_mr_init())
        printk(KERN_CRIT "inet_init: Cannot init ipv4 mroute\n");
#endif
    /* Initialise per-cpu ipv4 mibs */

    if (init_ipv4_mibs())
        printk(KERN_CRIT "inet_init: Cannot init ipv4 mibs\n");

    ipv4_proc_init();

    ipfrag_init();

    dev_add_pack(&ip_packet_type);

    rc = 0;
out:
    return rc;
out_unregister_udp_proto:
    proto_unregister(&udp_prot);
out_unregister_tcp_proto:
    proto_unregister(&tcp_prot);
    goto out;
}


 

先关注字体加大加粗的方法，其它慢慢介绍

 

 

 

 

 

 

 

 

 

最后把tcp ,udp , raw 这3种关于socket的数据结构的一览表贴出来，以后说明时一眼就能看出区别。