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| // net/ipv4/af_net.c
static int __init inet_init(void)
{
struct inet_protosw *q;
struct list_head *r;
int rc;
// 检查 inet_skb_parm 大小是否与 sk_buff 控制块的大小匹配
sock_skb_cb_check_size(sizeof(struct inet_skb_parm));
// 协议注册，将其挂载到/proc文件系统上。通过/proc/net/protocols可以看到注册协议的统计信息
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;
rc = proto_register(&ping_prot, 1);
if (rc)
goto out_unregister_raw_proto;
/*
* Tell SOCKET that we are alive...
*/
// 注册socket family, 当使用 socket(2) 中指定 family 时就能通过 inet_family_ops 中的inet_create 创建 ipv4 socket
(void)sock_register(&inet_family_ops);
#ifdef CONFIG_SYSCTL
ip_static_sysctl_init();
#endif
/*
* Add all the base protocols.
*/
// 注册传输层协议处理函数
if (inet_add_protocol(&icmp_protocol, IPPROTO_ICMP) < 0)
pr_crit("%s: Cannot add ICMP protocol\n", __func__);
if (inet_add_protocol(&udp_protocol, IPPROTO_UDP) < 0)
pr_crit("%s: Cannot add UDP protocol\n", __func__);
if (inet_add_protocol(&tcp_protocol, IPPROTO_TCP) < 0)
pr_crit("%s: Cannot add TCP protocol\n", __func__);
#ifdef CONFIG_IP_MULTICAST
if (inet_add_protocol(&igmp_protocol, IPPROTO_IGMP) < 0)
pr_crit("%s: Cannot add IGMP protocol\n", __func__);
#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();
/* Setup TCP slab cache for open requests. */
tcp_init();
/* Setup UDP memory threshold */
udp_init();
/* Add UDP-Lite (RFC 3828) */
udplite4_register();
raw_init();
ping_init();
/*
* 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())
pr_crit("%s: Cannot init ipv4 mroute\n", __func__);
#endif
if (init_inet_pernet_ops())
pr_crit("%s: Cannot init ipv4 inet pernet ops\n", __func__);
/*
* Initialise per-cpu ipv4 mibs
*/
if (init_ipv4_mibs())
pr_crit("%s: Cannot init ipv4 mibs\n", __func__);
ipv4_proc_init();
ipfrag_init();
dev_add_pack(&ip_packet_type);
ip_tunnel_core_init();
rc = 0;
out:
return rc;
out_unregister_raw_proto:
proto_unregister(&raw_prot);
out_unregister_udp_proto:
proto_unregister(&udp_prot);
out_unregister_tcp_proto:
proto_unregister(&tcp_prot);
goto out;
}
|