先說說為什麼要搭建本地軟體源，openwrt/LEDE穩定版軟體，驅動版本都比較舊，trunk版呢又更新的很快，系統裝上幾天又想要從官方伺服器上使用opkg裝軟體可能就裝不上了，所以最好的解決辦法就是在本地搭建一個軟體源，把正在使用的系統版本的所有軟體儲存下來。而且官方的源在國外，訪問速度極慢，使用本地的源可以跑滿內網頻寬。

官方的軟體源只有系統的基本軟體和不多的功能外掛，克隆到本地後，就有了對本地源完全的許可權，我們就可以往源新增新編譯的軟體了。

為了保證軟體的相容性，一般來說新增到源上的軟體都應該使用從相應的源提供的SDK打包，直接從系統原始碼和版本不一致的SDK打包的軟體都有可能裝不上。

給源新增軟體首先肯定是把編譯出來的ipk檔案上傳到伺服器，接著就是在索引中新增新增的軟體包的資訊，在軟體包生成的目錄中我們可以發現除了我們選中的軟體包之外還有三個檔案生成——Packages,Packages.gz,Packages.manifest，這幾個檔案就是提供軟體包的索引（在SDK下使用make package/xxxx/compile生成軟體包後不會生成索引，要直接使用make），索引類似下面的一段內容

Package: gdut-drcom
Version: 1.6.8-3
Depends: libc
License: GPL-3.0+
Section: net
Architecture
 
: mips_24kc
Installed-Size: 18513
Filename: gdut-drcom_1.6.8-3_mips_24kc.ipk
Size: 19427
SHA256sum: 4e35ea4c3efd54b0e7c02e90706dd61eb5645f1b8e7466b3c87f5247a0cdcc6e
Description:  gdut-drcom for openwrt is a third party drcom client openwrt.

得到索引資訊之後就是把這些資訊插到軟體源伺服器的索引中，最好按照軟體包的字母順序插入，儘量不要打亂原有檔案結構。

更新了3個索引檔案之後，先去路由裡面修改源伺服器，配置檔案是
/etc/opkg/distfeeds.conf ,按照原來的格式把伺服器地址改為本地伺服器地址

#src/gz reboot_core http://downloads.lede-project.org/snapshots/targets/ar71xx/generic/packages                                                   
#src/gz reboot_base http://downloads.lede-project.org/snapshots/packages/mips_24kc/base                                                           
#src/gz reboot_luci http://downloads.lede-project.org/snapshots/packages/mips_24kc/luci                                                           
#src/gz reboot_packages http://downloads.lede-project.org/snapshots/packages/mips_24kc/packages                                                   
#src/gz reboot_routing http://downloads.lede-project.org/snapshots/packages/mips_24kc/routing                                                     
#src/gz reboot_telephony http://downloads.lede-project.org/snapshots/packages/mips_24kc/telephony                                                 

src/gz reboot_packages http://10.99.100.160:8082/lede/package/mips_24kc/packages                                                                  
src/gz reboot_base http://10.99.100.160:8082/lede/package/mips_24kc/base                                                                          
src/gz reboot_luci http://10.99.100.160:8082/lede/package/mips_24kc/luci                                                                          
src/gz reboot_routing http://10.99.100.160:8082/lede/package/mips_24kc/routing                                                                    
src/gz reboot_telephony http://10.99.100.160:8082/lede/package/mips_24kc/telephony  

儲存之後執行opkg update更新本地索引

root@LEDE:~# opkg update
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_packages
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/packages/Packages.sig
Signature check passed.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/base/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_base
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/base/Packages.sig
Signature check failed.
Remove wrong Signature file.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/luci/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_luci
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/luci/Packages.sig
Signature check passed.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/routing/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_routing
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/routing/Packages.sig
Signature check passed.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/telephony/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_telephony
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/telephony/Packages.sig
Signature check passed.

可以看到路由已經從本地的源伺服器更新索引了，但是……我們修改過的那個base中的package簽名不通過，上網搜尋了一晚上，終於在openwrt官方論壇上找到了簽名的生成方法，我在這裡再翻譯一遍吧
首先，找到生成簽名的工具——usign，ubuntu中apt安裝不成功，納悶了許久最終在sdk裡面找到了這個工具，這個工具藏在，sdk目錄/staging_dir/host/bin中，下面就可以跟著官方論壇上的方法生成簽名了
第一步，生成一對公鑰和私鑰，公鑰用於路由對簽名檔案進行校驗，私鑰用於我們生成簽名檔案

[email protected]-linux:~/lede-sdk-ar71xx-generic_gcc-5.4.0_musl.Linux-x86_64/staging_dir/host/bin$ ./usign -G -s mime.key -p mime.pub

第二步，利用生成的私鑰對伺服器上的Packages檔案生成簽名檔案，Packages檔案不在當前目錄的話要加上路徑

[email protected]-linux:~/lede-sdk-ar71xx-generic_gcc-5.4.0_musl.Linux-x86_64/staging_dir/host/bin$ ./usign -S -m Packages -s mime.key -x Packages.sig

第三步，把簽名檔案上傳到伺服器上，把公鑰上傳到路由，在路由上新增我們生成的公鑰

root@LEDE:~# scp [email protected]:~/lede-sdk-ar71xx-generic_gcc-5.4.0_musl.Linux-x86_64/staging_dir/host/bin/mime.pub /tmp
hokamyuen@192.168.1.150's password: 
mime.pub                                                                                                        100%  104     0.1KB/s   00:00    
root@LEDE:~# cd /tmp
root@LEDE:/tmp# opkg-key add mime.pub
root@LEDE:/tmp# 

最後，在路由上重新更新軟體索引

root@LEDE:/tmp# opkg update
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_packages
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/packages/Packages.sig
Signature check passed.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/base/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_base
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/base/Packages.sig
Signature check passed.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/luci/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_luci
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/luci/Packages.sig
Signature check passed.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/routing/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_routing
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/routing/Packages.sig
Signature check passed.
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/telephony/Packages.gz
Updated list of available packages in /var/opkg-lists/reboot_telephony
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/telephony/Packages.sig
Signature check passed.

可以看到，簽名通過了，哈哈哈哈！
接下來就可以用opkg直接從伺服器上新編譯安裝軟體了

root@LEDE:/tmp# opkg install gdut-drcom
Installing gdut-drcom (1.6.8-3) to root...
Downloading http://10.99.100.160:8082/lede/package/mips_24kc/base/gdut-drcom_1.6.8-3_mips_24kc.ipk
Configuring gdut-drcom.
post install: patching ppp.sh
patched!
post install: patching ppp.sh
patched!
'radio0' is disabled
root@LEDE:/tmp# 

最後再寫一個新增索引的注意事項
有些包的索引會比伺服器上的多了一些奇怪的東西，例如

Package: libstdcpp
Version: 5.4.0-1
License: GPL-3.0-with-GCC-exception
Section: libs
Status: unknown hold not-installed
Essential: yes
Architecture: mips_24kc
Installed-Size: 375927
Filename: libstdcpp_5.4.0-1_mips_24kc.ipk
Size: 374075
SHA256sum: 689a6a67156f76afcafb4f3d545b02ac7972aa87ddb7b165406d98abe63fc070
Description:  GNU Standard C++ Library v3

只要把多出來的Status和Essential項刪掉就好。