1：简单网络管理（snmp）：是指管理指定协议的网络，如ip协议、icmp协议等，其中会将收到的ip数据存放到指定的文件夹中。 2：关于内核中的代码他的执行和平时写的c代码执行是有些不同的，（我的理解，我们写一些简单的内核模块时、是将一些代码写成一个小的工具，然后执行这个小的工具）。
内核中使用__init ipv6_misc_proc_init这个函数函数执行这个我们写的函数，使用ipv6_misc_proc_exit退出这个程序。
同时内核中使用insmode安装内核模块，将内核模块安装到内核中。
3：接下来说关于snmp的源码（我这里是在Linux内核4.1.51中寻找的源码）。
首先我们先将proc.c文件内容中的各种函数粘贴到这里，我这里逐一解释函数的作用。
//将套接口的状态显示到文件中。
static int sockstat6_seq_show(struct seq_file *seq, void *v)；
//打开保存套接口状态的文件。
static int sockstat6_seq_open(struct inode *inode, struct file *file)；
//将icmp6的数据显示到保存icmp6的文件中，可以在Linux系统/proc/net目录下找到。
static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, atomic_long_t *smib)；
//将snmp6的一些项显示到文件中，下面两个函数就是这个功能。
static void snmp6_seq_show_item(struct seq_file *seq, void __percpu *pcpumib,atomic_long_t *smib, const struct snmp_mib *itemlist)；
static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu *mib, const struct snmp_mib *itemlist, size_t syncpoff)；
//将各种信息调用上面两个函数分别显示到文件中
static int snmp6_seq_show(struct seq_file *seq, void *v)；
//这是将打开要显示的snmp6文件。
static int snmp6_seq_open(struct inode *inode, struct file *file)；
//dev文件的打开，我猜测是类似/proc/net/dev文件。
static int snmp6_dev_seq_show(struct seq_file *seq, void *v)；
static int snmp6_dev_seq_open(struct inode *inode, struct file *file)；
//下面六个文件前两个分别是snmp6文件的注册和解注册，中间两个是ipv6文件的注册和解注册，最后两个是程序的入口。
int snmp6_register_dev(struct inet6_dev *idev)；
int snmp6_unregister_dev(struct inet6_dev *idev)；
static int __net_init ipv6_proc_init_net(struct net *net)；
static void __net_exit ipv6_proc_exit_net(struct net *net)；
int __init ipv6_misc_proc_init(void)；
void ipv6_misc_proc_exit(void)；
第二部分：接下来我们说明一下此文档的数据结构。
下面这部分是其中一部分数据结构，snmp_mib是一个结构体（结构体中内容为名字和保存位置的行数。SNMP_MIB_ITEM是结构体内容初始化函数。
如果想看结构体数组中的具体内容，我们可以参考对应的rfc文档。如下面第一个黑体字。有些没有写对应rfc文档的根据名字就可以知道是干什么用的了。
static const struct snmp_mib snmp6_ipstats_list[] = {
/* ipv6 mib according to** RFC 2465** */
SNMP_MIB_ITEM("Ip6InReceives", IPSTATS_MIB_INPKTS),
SNMP_MIB_ITEM("Ip6InHdrErrors", IPSTATS_MIB_INHDRERRORS),
SNMP_MIB_ITEM("Ip6InTooBigErrors", IPSTATS_MIB_INTOOBIGERRORS),
SNMP_MIB_ITEM("Ip6InNoRoutes", IPSTATS_MIB_INNOROUTES),
SNMP_MIB_ITEM("Ip6InAddrErrors", IPSTATS_MIB_INADDRERRORS),
SNMP_MIB_ITEM("Ip6InUnknownProtos", IPSTATS_MIB_INUNKNOWNPROTOS),
SNMP_MIB_ITEM("Ip6InTruncatedPkts", IPSTATS_MIB_INTRUNCATEDPKTS),
SNMP_MIB_ITEM("Ip6InDiscards", IPSTATS_MIB_INDISCARDS),
SNMP_MIB_ITEM("Ip6InDelivers", IPSTATS_MIB_INDELIVERS),
SNMP_MIB_ITEM("Ip6OutForwDatagrams", IPSTATS_MIB_OUTFORWDATAGRAMS),
SNMP_MIB_ITEM("Ip6OutRequests", IPSTATS_MIB_OUTPKTS),
SNMP_MIB_ITEM("Ip6OutDiscards", IPSTATS_MIB_OUTDISCARDS),
SNMP_MIB_ITEM("Ip6OutNoRoutes", IPSTATS_MIB_OUTNOROUTES),
SNMP_MIB_ITEM("Ip6ReasmTimeout", IPSTATS_MIB_REASMTIMEOUT),
SNMP_MIB_ITEM("Ip6ReasmReqds", IPSTATS_MIB_REASMREQDS),
SNMP_MIB_ITEM("Ip6ReasmOKs", IPSTATS_MIB_REASMOKS),
SNMP_MIB_ITEM("Ip6ReasmFails", IPSTATS_MIB_REASMFAILS),
SNMP_MIB_ITEM("Ip6FragOKs", IPSTATS_MIB_FRAGOKS),
SNMP_MIB_ITEM("Ip6FragFails", IPSTATS_MIB_FRAGFAILS),
SNMP_MIB_ITEM("Ip6FragCreates", IPSTATS_MIB_FRAGCREATES),
SNMP_MIB_ITEM("Ip6InMcastPkts", IPSTATS_MIB_INMCASTPKTS),
SNMP_MIB_ITEM("Ip6OutMcastPkts", IPSTATS_MIB_OUTMCASTPKTS),
SNMP_MIB_ITEM("Ip6InOctets", IPSTATS_MIB_INOCTETS),
SNMP_MIB_ITEM("Ip6OutOctets", IPSTATS_MIB_OUTOCTETS),
SNMP_MIB_ITEM("Ip6InMcastOctets", IPSTATS_MIB_INMCASTOCTETS),
SNMP_MIB_ITEM("Ip6OutMcastOctets", IPSTATS_MIB_OUTMCASTOCTETS),
SNMP_MIB_ITEM("Ip6InBcastOctets", IPSTATS_MIB_INBCASTOCTETS),
SNMP_MIB_ITEM("Ip6OutBcastOctets", IPSTATS_MIB_OUTBCASTOCTETS),
/* IPSTATS_MIB_CSUMERRORS is not relevant in IPv6 (no checksum) */
SNMP_MIB_ITEM("Ip6InNoECTPkts", IPSTATS_MIB_NOECTPKTS),
SNMP_MIB_ITEM("Ip6InECT1Pkts", IPSTATS_MIB_ECT1PKTS),
SNMP_MIB_ITEM("Ip6InECT0Pkts", IPSTATS_MIB_ECT0PKTS),
SNMP_MIB_ITEM("Ip6InCEPkts", IPSTATS_MIB_CEPKTS),
SNMP_MIB_SENTINEL
};
static const struct snmp_mib snmp6_icmp6_list[] = {
/* icmpv6 mib according to RFC 2466 */
SNMP_MIB_ITEM("Icmp6InMsgs", ICMP6_MIB_INMSGS),
SNMP_MIB_ITEM("Icmp6InErrors", ICMP6_MIB_INERRORS),
SNMP_MIB_ITEM("Icmp6OutMsgs", ICMP6_MIB_OUTMSGS),
SNMP_MIB_ITEM("Icmp6OutErrors", ICMP6_MIB_OUTERRORS),
SNMP_MIB_ITEM("Icmp6InCsumErrors", ICMP6_MIB_CSUMERRORS),
SNMP_MIB_SENTINEL
};
/* RFC 4293 v6 ICMPMsgStatsTable; named items for RFC 2466 compatibility */
static const char *const icmp6type2name[256] = {
[ICMPV6_DEST_UNREACH] = "DestUnreachs",
[ICMPV6_PKT_TOOBIG] = "PktTooBigs",
[ICMPV6_TIME_EXCEED] = "TimeExcds",
[ICMPV6_PARAMPROB] = "ParmProblems",
[ICMPV6_ECHO_REQUEST] = "Echos",
[ICMPV6_ECHO_REPLY] = "EchoReplies",
[ICMPV6_MGM_QUERY] = "GroupMembQueries",
[ICMPV6_MGM_REPORT] = "GroupMembResponses",
[ICMPV6_MGM_REDUCTION] = "GroupMembReductions",
[ICMPV6_MLD2_REPORT] = "MLDv2Reports",
[NDISC_ROUTER_ADVERTISEMENT] = "RouterAdvertisements",
[NDISC_ROUTER_SOLICITATION] = "RouterSolicits",
[NDISC_NEIGHBOUR_ADVERTISEMENT] = "NeighborAdvertisements",
[NDISC_NEIGHBOUR_SOLICITATION] = "NeighborSolicits",
[NDISC_REDIRECT] = "Redirects",
};
static const struct snmp_mib snmp6_udp6_list[] = {
SNMP_MIB_ITEM("Udp6InDatagrams", UDP_MIB_INDATAGRAMS),
SNMP_MIB_ITEM("Udp6NoPorts", UDP_MIB_NOPORTS),
SNMP_MIB_ITEM("Udp6InErrors", UDP_MIB_INERRORS),
SNMP_MIB_ITEM("Udp6OutDatagrams", UDP_MIB_OUTDATAGRAMS),
SNMP_MIB_ITEM("Udp6RcvbufErrors", UDP_MIB_RCVBUFERRORS),
SNMP_MIB_ITEM("Udp6SndbufErrors", UDP_MIB_SNDBUFERRORS),
SNMP_MIB_ITEM("Udp6InCsumErrors", UDP_MIB_CSUMERRORS),
SNMP_MIB_ITEM("Udp6IgnoredMulti", UDP_MIB_IGNOREDMULTI),
SNMP_MIB_SENTINEL
};
static const struct snmp_mib snmp6_udplite6_list[] = {
SNMP_MIB_ITEM("UdpLite6InDatagrams", UDP_MIB_INDATAGRAMS),
SNMP_MIB_ITEM("UdpLite6NoPorts", UDP_MIB_NOPORTS),
SNMP_MIB_ITEM("UdpLite6InErrors", UDP_MIB_INERRORS),
SNMP_MIB_ITEM("UdpLite6OutDatagrams", UDP_MIB_OUTDATAGRAMS),
SNMP_MIB_ITEM("UdpLite6RcvbufErrors", UDP_MIB_RCVBUFERRORS),
SNMP_MIB_ITEM("UdpLite6SndbufErrors", UDP_MIB_SNDBUFERRORS),
SNMP_MIB_ITEM("UdpLite6InCsumErrors", UDP_MIB_CSUMERRORS),
SNMP_MIB_SENTINEL
};
接下来这部分结构体如下所示。他是定位到文件的指定位置。
static const struct file_operations snmp6_seq_fops = {
.owner = THIS_MODULE,
.open = snmp6_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release_net,
};
第三部分：这部分我将源代码贴上去，并且将进入函数执行流程分析一边，对应的分析退出函数的流程。
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* This file implements the various access functions for the
* PROC file system. This is very similar to the IPv4 version,
* except it reports the sockets in the INET6 address family.
*
* Authors: David S. Miller (davem@caip.rutgers.edu)
* YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/ipv6.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stddef.h>
#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/transp_v6.h>
#include <net/ipv6.h>
static int sockstat6_seq_show(struct seq_file *seq, void *v)
{
struct net *net = seq->private;
unsigned int frag_mem = ip6_frag_mem(net);
seq_printf(seq, "TCP6: inuse %d\n",
sock_prot_inuse_get(net, &tcpv6_prot));
seq_printf(seq, "UDP6: inuse %d\n",
sock_prot_inuse_get(net, &udpv6_prot));
seq_printf(seq, "UDPLITE6: inuse %d\n",
sock_prot_inuse_get(net, &udplitev6_prot));
seq_printf(seq, "RAW6: inuse %d\n",
sock_prot_inuse_get(net, &rawv6_prot));
seq_printf(seq, "FRAG6: inuse %u memory %u\n", !!frag_mem, frag_mem);
return 0;
}
static int sockstat6_seq_open(struct inode *inode, struct file *file)
{
return single_open_net(inode, file, sockstat6_seq_show);
}
static const struct file_operations sockstat6_seq_fops = {
.owner = THIS_MODULE,
.open = sockstat6_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release_net,
};
static const struct snmp_mib snmp6_ipstats_list[] = {
/* ipv6 mib according to RFC 2465 */
SNMP_MIB_ITEM("Ip6InReceives", IPSTATS_MIB_INPKTS),
SNMP_MIB_ITEM("Ip6InHdrErrors", IPSTATS_MIB_INHDRERRORS),
SNMP_MIB_ITEM("Ip6InTooBigErrors", IPSTATS_MIB_INTOOBIGERRORS),
SNMP_MIB_ITEM("Ip6InNoRoutes", IPSTATS_MIB_INNOROUTES),
SNMP_MIB_ITEM("Ip6InAddrErrors", IPSTATS_MIB_INADDRERRORS),
SNMP_MIB_ITEM("Ip6InUnknownProtos", IPSTATS_MIB_INUNKNOWNPROTOS),
SNMP_MIB_ITEM("Ip6InTruncatedPkts", IPSTATS_MIB_INTRUNCATEDPKTS),
SNMP_MIB_ITEM("Ip6InDiscards", IPSTATS_MIB_INDISCARDS),
SNMP_MIB_ITEM("Ip6InDelivers", IPSTATS_MIB_INDELIVERS),
SNMP_MIB_ITEM("Ip6OutForwDatagrams", IPSTATS_MIB_OUTFORWDATAGRAMS),
SNMP_MIB_ITEM("Ip6OutRequests", IPSTATS_MIB_OUTPKTS),
SNMP_MIB_ITEM("Ip6OutDiscards", IPSTATS_MIB_OUTDISCARDS),
SNMP_MIB_ITEM("Ip6OutNoRoutes", IPSTATS_MIB_OUTNOROUTES),
SNMP_MIB_ITEM("Ip6ReasmTimeout", IPSTATS_MIB_REASMTIMEOUT),
SNMP_MIB_ITEM("Ip6ReasmReqds", IPSTATS_MIB_REASMREQDS),
SNMP_MIB_ITEM("Ip6ReasmOKs", IPSTATS_MIB_REASMOKS),
SNMP_MIB_ITEM("Ip6ReasmFails", IPSTATS_MIB_REASMFAILS),
SNMP_MIB_ITEM("Ip6FragOKs", IPSTATS_MIB_FRAGOKS),
SNMP_MIB_ITEM("Ip6FragFails", IPSTATS_MIB_FRAGFAILS),
SNMP_MIB_ITEM("Ip6FragCreates", IPSTATS_MIB_FRAGCREATES),
SNMP_MIB_ITEM("Ip6InMcastPkts", IPSTATS_MIB_INMCASTPKTS),
SNMP_MIB_ITEM("Ip6OutMcastPkts", IPSTATS_MIB_OUTMCASTPKTS),
SNMP_MIB_ITEM("Ip6InOctets", IPSTATS_MIB_INOCTETS),
SNMP_MIB_ITEM("Ip6OutOctets", IPSTATS_MIB_OUTOCTETS),
SNMP_MIB_ITEM("Ip6InMcastOctets", IPSTATS_MIB_INMCASTOCTETS),
SNMP_MIB_ITEM("Ip6OutMcastOctets", IPSTATS_MIB_OUTMCASTOCTETS),
SNMP_MIB_ITEM("Ip6InBcastOctets", IPSTATS_MIB_INBCASTOCTETS),
SNMP_MIB_ITEM("Ip6OutBcastOctets", IPSTATS_MIB_OUTBCASTOCTETS),
/* IPSTATS_MIB_CSUMERRORS is not relevant in IPv6 (no checksum) */
SNMP_MIB_ITEM("Ip6InNoECTPkts", IPSTATS_MIB_NOECTPKTS),
SNMP_MIB_ITEM("Ip6InECT1Pkts", IPSTATS_MIB_ECT1PKTS),
SNMP_MIB_ITEM("Ip6InECT0Pkts", IPSTATS_MIB_ECT0PKTS),
SNMP_MIB_ITEM("Ip6InCEPkts", IPSTATS_MIB_CEPKTS),
SNMP_MIB_SENTINEL
};
static const struct snmp_mib snmp6_icmp6_list[] = {
/* icmpv6 mib according to RFC 2466 */
SNMP_MIB_ITEM("Icmp6InMsgs", ICMP6_MIB_INMSGS),
SNMP_MIB_ITEM("Icmp6InErrors", ICMP6_MIB_INERRORS),
SNMP_MIB_ITEM("Icmp6OutMsgs", ICMP6_MIB_OUTMSGS),
SNMP_MIB_ITEM("Icmp6OutErrors", ICMP6_MIB_OUTERRORS),
SNMP_MIB_ITEM("Icmp6InCsumErrors", ICMP6_MIB_CSUMERRORS),
SNMP_MIB_SENTINEL
};
/* RFC 4293 v6 ICMPMsgStatsTable; named items for RFC 2466 compatibility */
static const char *const icmp6type2name[256] = {
[ICMPV6_DEST_UNREACH] = "DestUnreachs",
[ICMPV6_PKT_TOOBIG] = "PktTooBigs",
[ICMPV6_TIME_EXCEED] = "TimeExcds",
[ICMPV6_PARAMPROB] = "ParmProblems",
[ICMPV6_ECHO_REQUEST] = "Echos",
[ICMPV6_ECHO_REPLY] = "EchoReplies",
[ICMPV6_MGM_QUERY] = "GroupMembQueries",
[ICMPV6_MGM_REPORT] = "GroupMembResponses",
[ICMPV6_MGM_REDUCTION] = "GroupMembReductions",
[ICMPV6_MLD2_REPORT] = "MLDv2Reports",
[NDISC_ROUTER_ADVERTISEMENT] = "RouterAdvertisements",
[NDISC_ROUTER_SOLICITATION] = "RouterSolicits",
[NDISC_NEIGHBOUR_ADVERTISEMENT] = "NeighborAdvertisements",
[NDISC_NEIGHBOUR_SOLICITATION] = "NeighborSolicits",
[NDISC_REDIRECT] = "Redirects",
};
static const struct snmp_mib snmp6_udp6_list[] = {
SNMP_MIB_ITEM("Udp6InDatagrams", UDP_MIB_INDATAGRAMS),
SNMP_MIB_ITEM("Udp6NoPorts", UDP_MIB_NOPORTS),
SNMP_MIB_ITEM("Udp6InErrors", UDP_MIB_INERRORS),
SNMP_MIB_ITEM("Udp6OutDatagrams", UDP_MIB_OUTDATAGRAMS),
SNMP_MIB_ITEM("Udp6RcvbufErrors", UDP_MIB_RCVBUFERRORS),
SNMP_MIB_ITEM("Udp6SndbufErrors", UDP_MIB_SNDBUFERRORS),
SNMP_MIB_ITEM("Udp6InCsumErrors", UDP_MIB_CSUMERRORS),
SNMP_MIB_ITEM("Udp6IgnoredMulti", UDP_MIB_IGNOREDMULTI),
SNMP_MIB_SENTINEL
};
static const struct snmp_mib snmp6_udplite6_list[] = {
SNMP_MIB_ITEM("UdpLite6InDatagrams", UDP_MIB_INDATAGRAMS),
SNMP_MIB_ITEM("UdpLite6NoPorts", UDP_MIB_NOPORTS),
SNMP_MIB_ITEM("UdpLite6InErrors", UDP_MIB_INERRORS),
SNMP_MIB_ITEM("UdpLite6OutDatagrams", UDP_MIB_OUTDATAGRAMS),
SNMP_MIB_ITEM("UdpLite6RcvbufErrors", UDP_MIB_RCVBUFERRORS),
SNMP_MIB_ITEM("UdpLite6SndbufErrors", UDP_MIB_SNDBUFERRORS),
SNMP_MIB_ITEM("UdpLite6InCsumErrors", UDP_MIB_CSUMERRORS),
SNMP_MIB_SENTINEL
};
static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, atomic_long_t *smib)
{
char name[32];
int i;
/* print by name -- deprecated items */
for (i = 0; i < ICMP6MSG_MIB_MAX; i++) {
int icmptype;
const char *p;
icmptype = i & 0xff;
p = icmp6type2name[icmptype];
if (!p) /* don't print un-named types here */
continue;
snprintf(name, sizeof(name), "Icmp6%s%s",
i & 0x100 ? "Out" : "In", p);
seq_printf(seq, "%-32s\t%lu\n", name,
atomic_long_read(smib + i));
}
/* print by number (nonzero only) - ICMPMsgStat format */
for (i = 0; i < ICMP6MSG_MIB_MAX; i++) {
unsigned long val;
val = atomic_long_read(smib + i);
if (!val)
continue;
snprintf(name, sizeof(name), "Icmp6%sType%u",
i & 0x100 ? "Out" : "In", i & 0xff);
seq_printf(seq, "%-32s\t%lu\n", name, val);
}
}
/* can be called either with percpu mib (pcpumib != NULL),
* or shared one (smib != NULL)
*/
static void snmp6_seq_show_item(struct seq_file *seq, void __percpu *pcpumib,
atomic_long_t *smib,
const struct snmp_mib *itemlist)
{
int i;
unsigned long val;
for (i = 0; itemlist[i].name; i++) {
val = pcpumib ?
snmp_fold_field(pcpumib, itemlist[i].entry) :
atomic_long_read(smib + itemlist[i].entry);
seq_printf(seq, "%-32s\t%lu\n", itemlist[i].name, val);
}
}
static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu *mib,
const struct snmp_mib *itemlist, size_t syncpoff)
{
int i;
for (i = 0; itemlist[i].name; i++)
seq_printf(seq, "%-32s\t%llu\n", itemlist[i].name,
snmp_fold_field64(mib, itemlist[i].entry, syncpoff));
}
static int snmp6_seq_show(struct seq_file *seq, void *v)
{
struct net *net = (struct net *)seq->private;
snmp6_seq_show_item64(seq, net->mib.ipv6_statistics,
snmp6_ipstats_list, offsetof(struct ipstats_mib, syncp));
snmp6_seq_show_item(seq, net->mib.icmpv6_statistics,
NULL, snmp6_icmp6_list);
snmp6_seq_show_icmpv6msg(seq, net->mib.icmpv6msg_statistics->mibs);
snmp6_seq_show_item(seq, net->mib.udp_stats_in6,
NULL, snmp6_udp6_list);
snmp6_seq_show_item(seq, net->mib.udplite_stats_in6,
NULL, snmp6_udplite6_list);
return 0;
}
static int snmp6_seq_open(struct inode *inode, struct file *file)
{
return single_open_net(inode, file, snmp6_seq_show);
}
static const struct file_operations snmp6_seq_fops = {
.owner = THIS_MODULE,
.open = snmp6_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release_net,
};
static int snmp6_dev_seq_show(struct seq_file *seq, void *v)
{
struct inet6_dev *idev = (struct inet6_dev *)seq->private;
seq_printf(seq, "%-32s\t%u\n", "ifIndex", idev->dev->ifindex);
snmp6_seq_show_item64(seq, idev->stats.ipv6,
snmp6_ipstats_list, offsetof(struct ipstats_mib, syncp));
snmp6_seq_show_item(seq, NULL, idev->stats.icmpv6dev->mibs,
snmp6_icmp6_list);
snmp6_seq_show_icmpv6msg(seq, idev->stats.icmpv6msgdev->mibs);
return 0;
}
static int snmp6_dev_seq_open(struct inode *inode, struct file *file)
{
return single_open(file, snmp6_dev_seq_show, PDE_DATA(inode));
}
static const struct file_operations snmp6_dev_seq_fops = {
.owner = THIS_MODULE,
.open = snmp6_dev_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
int snmp6_register_dev(struct inet6_dev *idev)
{
struct proc_dir_entry *p;
struct net *net;
if (!idev || !idev->dev)
return -EINVAL;
net = dev_net(idev->dev);
if (!net->mib.proc_net_devsnmp6)
return -ENOENT;
p = proc_create_data(idev->dev->name, S_IRUGO,
net->mib.proc_net_devsnmp6,
&snmp6_dev_seq_fops, idev);
if (!p)
return -ENOMEM;
idev->stats.proc_dir_entry = p;
return 0;
}
int snmp6_unregister_dev(struct inet6_dev *idev)
{
struct net *net = dev_net(idev->dev);
if (!net->mib.proc_net_devsnmp6)
return -ENOENT;
if (!idev->stats.proc_dir_entry)
return -EINVAL;
proc_remove(idev->stats.proc_dir_entry);
idev->stats.proc_dir_entry = NULL;
return 0;
}
static int __net_init ipv6_proc_init_net(struct net *net)
{
if (!proc_create("sockstat6", S_IRUGO, net->proc_net,
&sockstat6_seq_fops))
return -ENOMEM;
if (!proc_create("snmp6", S_IRUGO, net->proc_net, &snmp6_seq_fops))
goto proc_snmp6_fail;
net->mib.proc_net_devsnmp6 = proc_mkdir("dev_snmp6", net->proc_net);
if (!net->mib.proc_net_devsnmp6)
goto proc_dev_snmp6_fail;
return 0;
proc_dev_snmp6_fail:
remove_proc_entry("snmp6", net->proc_net);
proc_snmp6_fail:
remove_proc_entry("sockstat6", net->proc_net);
return -ENOMEM;
}
static void __net_exit ipv6_proc_exit_net(struct net *net)
{
remove_proc_entry("sockstat6", net->proc_net);
remove_proc_entry("dev_snmp6", net->proc_net);
remove_proc_entry("snmp6", net->proc_net);
}
static struct pernet_operations ipv6_proc_ops = {
.init = ipv6_proc_init_net,
.exit = ipv6_proc_exit_net,
};
int __init ipv6_misc_proc_init(void)
{
return register_pernet_subsys(&ipv6_proc_ops);
}
void ipv6_misc_proc_exit(void)
{
unregister_pernet_subsys(&ipv6_proc_ops);
}
是u先是从从ipv6_misc_proc_init函数中调用函数进行注册，也就是接下来执行ipv6_proc_init_net这个函数。在这个函数中分别进行创建对应的内容，然后执行如if (!proc_create("sockstat6", S_IRUGO, net->proc_net, &sockstat6_seq_fops))中的sockstat6_seq_fops部分中的sockstat6_seq_open，之后执行single_open_net(inode, file, sockstat6_seq_show);中的sockstat6_seq_show函数，最后就是将各种数据显示到对应的文件中去了。
关于snmp文件可以参考rfc文档，
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