HOSTAPD wpa_supplicant Madwifi Detailed analysis (14)--End of article

Note: This article does not talk about technology

Check out the "HOSTAPD wpa_supplicant Madwifi Detailed analysis" series of articles, intermittent update to now, found that the middle of the duration is nearly two years. Remember that time just graduated to the company, the team leader asked me to see the wireless part of the project code, their own silly look at one months, the leader asked me:

How is VAP created? How are the STA and AP connected? How does WDS work? What is the difference between pin and pushbutton in WPS? How are several encryption methods in our DUT implemented? What is HOSTAPD used for?

I was so embarrassed by these questions that I felt that what I had spent one months learning was trivial to them. Later decided to start from HOSTAPD deep learning, while summing up their own ideas.

Although the above problems have been clear, but for various reasons have been interrupted, failed to update in a timely manner. More importantly, the more you find that there are more things to add, the more you will find their own description of the loopholes too much, the more dare not easy to write, so as not to bring anything misleading.

Then do Cisco's project, responsible for the function of the captive portal, a figure is two months, careless right, and then own the Netgear Extender project, busy before busy, a full nine months, small rookie always because of various problems to get the burn, Will because can not think of the solution and distracted, that period of time, overtime is simply a routine, if one day did not work overtime in the heart but will feel empty, now think about then really wayward!

The first article in this series is what does the HOSTAPD do? ", in fact, when the answer is not good, as the end of the article, here to answer:

HOSTAPD is an application that, as a process of working in the application layer, can do what it does, much depends on the kernel and the driver, and HOSTAPD is the wireless-related process, so it is more dependent on the WiFi driver. If you want to ask HOSTAPD is why, mainly based on WiFi driver to ask, different wireless chip manufacturers have different implementations, have to provide different WiFi driver, so the need to hostapd to supplement the corresponding features of the WiFi driver, HOSTAPD is the right-arm for Wireless LAN, such as QCA, but for a WiFi driver that does not require HOSTAPD to provide services that can encapsulate the functionality, HOSTAPD is not very useful. such as MTK.

HOSTAPD can accomplish almost any wireless configuration work that other wireless tools can accomplish, such as Iwconfig,iwpriv, Wlanconfig, Iwlist, and so on, HOSTAPD it can be done.

HOSTAPD can also complete the work that the wireless tool does not do, including WPA/WPA2 encryption, RADIUS encryption, Wps,pin, and other functions.

So in the application layer, WiFi this piece often as long as a HOSTAPD process is enough, especially for the STA interface, such as mobile phones, often as long as a wpa_supplicant process can do most of the WiFi work. Therefore, HOSTAPD can not only complete the configuration of the wireless interface in the application layer, but also obtain the information of the wireless interface, and can realize the encryption function of the corresponding interface.

The previous series of articles, although the introduction of HOSTAPD and wpa_supplicant Some of the things, is not very comprehensive, most of it is just a summary, not in depth, of course, for an application to go deep to where it seems not too realistic, Unless you know more about driver and wireless network protocols. Later should not write this series of articles, but will be on the previous article maintenance, to enrich, but also maintain a hostapd.git warehouse, some of the code to comment, interested students can come here clone view [email protected] : Lee244868149/hostapd.git.

In front of those articles, the main information is from the Web search (there are offensive to the original author's Place also pointed out, will be corrected) as well as the RfC, personal referral to the official standard documents, after all, through other people's collation, there may be errors, other people's books or articles should be used to help us better understand the RFC, Ultimately, it's up to the RFC to find the original basis. The following is the relevant RFC:

802.1x-2004.pdf

IEEE STD 802.1x-2010.pdf

rfc4137. state-machines-for-extensible-authentication-protocol-(EAP)-peer-and-authenticator.pdf

802.11-2012.pdf

Wi-fi_simple_configuration_technical_specification_v2.0.5.pdf

Wpa_supplicant-devel.pdf

IEEE STD 802.1ar-2009 IEEE Standard for Local and metropolitan area Networks-secure Device identity.pdf

HOSTAPD wpa_supplicant Madwifi Detailed analysis (14)--end of article