blocks|key|4448530|text|您可以使用strtol将每个部分转换为整数形式。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4448531|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cplusplus.com/reference/clibrary/cstdlib/strtol.html^0|5|6|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

You can use <a href="http://www.cplusplus.com/reference/clibrary/cstdlib/strtol.html" rel="nofollow noreferrer">strtol</a> to convert each piece to it's integer form.

blocks|key|384151|text|很简单。“x.x”格式的IP地址被称为点分四元组是有原因的。每个数字代表一个字节，在您的地址中总共有4个字节。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|384152|因此，对于4字节的地址，您只需打印每个字节的十进制值。|384153|简单明了的示例(将printf替换为您选择的输出函数)：|384154|unsigned+char+*addr+=+(unsigned+char*)sk_buff->addr;
printf("%25d.%25d.%25d.%25d",+addr[0],+addr[1],+addr[2],+addr[3]);|code-block|syntax|javascript|384155|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Simple. The IP address in "x.x.x.x" format is called dotted-quad for a reason. Each number represents a byte, for a total of 4 bytes in your address.

So, with the 4 byte address, you would simply print the decimal value of each byte.

Quick and dirty example (replace printf with your output function of choice):

<pre><code>unsigned char *addr = (unsigned char*)sk_buff-&gt;addr;
printf("%d.%d.%d.%d", addr[0], addr[1], addr[2], addr[3]);
</code></pre>

blocks|key|384182|text|/*+Convinience+union+to+__be32+to+ip+address++*/
union+ip_address+{
++++u8+a[4];
++++__be32+saddr;
};|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|384183|IP地址可以获取a.a1.a2.a3|unstyled|384184|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>/* Convinience union to __be32 to ip address */
union ip_address {
 u8 a[4];
 __be32 saddr;
};
</code></pre>

IP Address could be obtained a[0].a[1].a[2].a[3]

blocks|key|1054619|text|include/linux/kernel.h中定义了两个宏|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1054620|ipv4地址的NIP6和ipv6地址的NIPQUAD。|1054621|#define+NIPQUAD(addr)+\
++++((unsigned+char+*)&addr)[0],+\
++++((unsigned+char+*)&addr)[1],+\
++++((unsigned+char+*)&addr)[2],+\
++++((unsigned+char+*)&addr)[3]

#define+NIP6(addr)+\
++++ntohs((addr).s6_addr16[0]),+\
++++ntohs((addr).s6_addr16[1]),+\
++++ntohs((addr).s6_addr16[2]),+\
++++ntohs((addr).s6_addr16[3]),+\
++++ntohs((addr).s6_addr16[4]),+\
++++ntohs((addr).s6_addr16[5]),+\
++++ntohs((addr).s6_addr16[6]),+\
++++ntohs((addr).s6_addr16[7])|code-block|syntax|javascript|1054622|内核源代码中有大量的示例，它们利用这些示例以人类可读的格式打印ip地址。例如：|1054623|printk(KERN_DEBUG+"Received+packet+from+source+address:+%25d.%25d.%25d.%25d!\n",NIPQUAD(iph->saddr));|1054624|希望这能有所帮助。|1054625|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

There are two macros defined in include/linux/kernel.h 

NIPQUAD for ipv4 addresses and NIP6 for ipv6 addresses. 

<pre><code>#define NIPQUAD(addr) \
 ((unsigned char *)&amp;addr)[0], \
 ((unsigned char *)&amp;addr)[1], \
 ((unsigned char *)&amp;addr)[2], \
 ((unsigned char *)&amp;addr)[3]

#define NIP6(addr) \
 ntohs((addr).s6_addr16[0]), \
 ntohs((addr).s6_addr16[1]), \
 ntohs((addr).s6_addr16[2]), \
 ntohs((addr).s6_addr16[3]), \
 ntohs((addr).s6_addr16[4]), \
 ntohs((addr).s6_addr16[5]), \
 ntohs((addr).s6_addr16[6]), \
 ntohs((addr).s6_addr16[7])
</code></pre>

There are ample examples in the kernel sources that make use of these to print ip addresses in human-readable format. For instance:

<pre><code>printk(KERN_DEBUG "Received packet from source address: %d.%d.%d.%d!\n",NIPQUAD(iph-&gt;saddr));
</code></pre>

Hope this helps.

blocks|key|4448669|text|您应该使用printk()提供的%25pI4扩展格式说明符：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4448670|printk(KERN_DEBUG+"IP+addres+=+%25pI4\n",+&local_ip);|code-block|syntax|javascript|4448671|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You should use the %pI4 extended format specifiers provided by printk():

<pre><code>printk(KERN_DEBUG "IP addres = %pI4\n", &amp;local_ip);
</code></pre>

blocks|key|384292|text|printk可以直接处理这个问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|384293|IPv4地址：|384294|%25pI4++++1.2.3.4
%25pi4++++001.002.003.004
%25p[Ii]4[hnbl]

For+printing+IPv4+dot-separated+decimal+addresses.+The+'I4'+and+'i4'
specifiers+result+in+a+printed+address+with+('i4')+or+without+('I4')
leading+zeros.

The+additional+'h',+'n',+'b',+and+'l'+specifiers+are+used+to+specify
host,+network,+big+or+little+endian+order+addresses+respectively.+Where
no+specifier+is+provided+the+default+network/big+endian+order+is+used.

Passed+by+reference.|code-block|syntax|javascript|384295|IPv6地址：|384296|%25pI6++++0001:0002:0003:0004:0005:0006:0007:0008
%25pi6++++00010002000300040005000600070008
%25pI6c+++1:2:3:4:5:6:7:8

For+printing+IPv6+network-order+16-bit+hex+addresses.+The+'I6'+and+'i6'
specifiers+result+in+a+printed+address+with+('I6')+or+without+('i6')
colon-separators.+Leading+zeros+are+always+used.

The+additional+'c'+specifier+can+be+used+with+the+'I'+specifier+to
print+a+compressed+IPv6+address+as+described+by
http://tools.ietf.org/html/rfc5952

Passed+by+reference.|384297|参考：https://www.kernel.org/doc/Documentation/printk-formats.txt|offset|length|384298|entityMap|0|LINK|mutability|MUTABLE|url|https://www.kernel.org/doc/Documentation/printk-formats.txt^0|0|0|0|0|0|3|1N|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|13|8|@]|9|@$O|14|P|15|1|16]]|A|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]]]

printk can handle this directly:

IPv4 addresses:

<pre><code>%pI4 1.2.3.4
%pi4 001.002.003.004
%p[Ii]4[hnbl]

For printing IPv4 dot-separated decimal addresses. The 'I4' and 'i4'
specifiers result in a printed address with ('i4') or without ('I4')
leading zeros.

The additional 'h', 'n', 'b', and 'l' specifiers are used to specify
host, network, big or little endian order addresses respectively. Where
no specifier is provided the default network/big endian order is used.

Passed by reference.
</code></pre>

IPv6 addresses:

<pre><code>%pI6 0001:0002:0003:0004:0005:0006:0007:0008
%pi6 00010002000300040005000600070008
%pI6c 1:2:3:4:5:6:7:8

For printing IPv6 network-order 16-bit hex addresses. The 'I6' and 'i6'
specifiers result in a printed address with ('I6') or without ('i6')
colon-separators. Leading zeros are always used.

The additional 'c' specifier can be used with the 'I' specifier to
print a compressed IPv6 address as described by
http://tools.ietf.org/html/rfc5952

Passed by reference.
</code></pre>

Reference: <a href="https://www.kernel.org/doc/Documentation/printk-formats.txt" rel="nofollow">https://www.kernel.org/doc/Documentation/printk-formats.txt</a>

I am writing a kernel module which registers a netfilter hook. I am trying to get the ip address of the caller by using the <code>sk_buff-&gt;saddr</code> member. Is there a way I can get the IP in human readable i.e. x.x.x.x format? 

I found the function <code>inet_ntop()</code> but it doesn't seem to be available in kernel headers. How do I convert \xC0\xA8\x00\x01 to 192.168.0.1 ?

IP-address from sk_buff

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在编写一个注册netfilter钩子的内核模块。我正在尝试使用sk_buff->saddr成员获取呼叫者的ip地址。有没有办法获得人类可读的IP，即x.x格式？我找到了函数inet_ntop()，但它似乎在内核头文件中不可用。如何将\xC0\xA8\x00\x01转换为192.168.0.1？

问来自sk_buff的IP地址
EN

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问来自sk_buff的IP地址EN