DHCP: Analysis of 2 implementation methods for dynamically acquiring IP on the Development Board _c language

Dhcp
The Dynamic Host Setup protocol, which is a network protocol of a LAN, uses UDP protocol to work for two main purposes: Configuration Protocol, DHCP.
1. Automatically assign IP addresses to internal networks or network service providers
2. Give the user to the internal network administrator as a means of central management of all computers.

method One: Dhclient
1. Download
https://www.isc.org/software/dhcp/
2. Decompression
TAR-ZXVF dhcp-3.1.3.tar.gz
3. Configure
cddhcp-3.1.3
./configure
The work.linux-2.2 folder is generated after success.
4. Compile
Make "Cc=/opt/hisi-linux/x86-arm/gcc-3.4.3-uclibc-0.9.28/usr/bin/arm-hismall-linux-gcc-static"
You can make it in the Work.linux-2.2/client directory or in the dhcp-3.1.3 directory,
5. Copy
Build Dhclient in Work.linux-2.2\client compilation.
Copy configuration filedhcp-3.1.3/client/dhclient.confAnd/dhcp-3.1.3/client/scripts/linuxTo the/sbin/directory of the developer board, and the Linux file is renamed toDhclient-script, and modify the first line of the file#!/bin/bashFor#!/bin/sh, after saving, modify permissionschmod +x/sbin/dhclient-script
6. Create a table of contents
mkdir-p/var/state/dhcp
Create a state directory under the/var directory, and then create a DHCP directory under the State directory.
7. Run
Dhclient RA0
Results:

Copy Code code as follows:

Internetsystems Consortium DHCP Client V3.1.3
copyright2004-2009 Internet Systems Consortium.
Allrights reserved.
Forinfo, please visit https://www.isc.org/software/dhcp/
Listeningon lpf/ra0/7c:dd:90:25:9f:a9
Sendingon lpf/ra0/7c:dd:90:25:9f:a9
Sendingon Socket/fallback
Dhcpdiscoveron ra0 to 255.255.255.255 port interval 6
Dhcpdiscoveron ra0 to 255.255.255.255 port interval 12
Dhcpdiscoveron ra0 to 255.255.255.255 port interval 14
Dhcpofferfrom 192.168.1.1
Dhcprequeston RA0 to 255.255.255.255 port 67
Dhcpackfrom 192.168.1.1
Bound to 192.168.1.31-renewal in 282261 seconds.

Method Two, Udhcpc
Udhcpc is a very small DHCP client for embedded systems, the initials micro-DHCP-client (ΜDHCPC).
1.udhcpc-i eth0
udhcpc Just get an IP, we need to put \busybox-1.1.2\examples\ UDHCP script Simple.script renamed to Default.script, placed on the Development Board/usr/share/dhcpc/directory, in order to write the acquired IP to the specified network card.
2.ifconfig