osi protocol stack

I use Ubuntu in Linux, which comes with the bluetooth protocol stack. However, there is a problem with the bluetooth protocol stack, that is, retransmission. Data loss is inevitable during transmission, to ensure effective data transmission, we only need to enter the command $ sudoaptitudesearchbluez * When we need to

kernel State based on NetFilter constructs SKB data packetThe previous fourth article introduces the NetFilter hook mechanism, we know that packets in the protocol stack pass through different hook points, and each hook point is NetFilter pre-registration a series of hook callback function, Each packet passes through the processing of these hook functions. In the hook callback function, you can do anything

Analysis of TCP/IP protocol stack (1) 1. layer: TCP/IP is divided into four layers: link layer, network layer, transmission layer, and application layer. The most critical two layers are the network layer and transmission layer. The network layer provides point-to-point services for IP addressing, the Transport Layer implements end-to-end services for reliable TCP data transmission and UDP data transmission

When looking at the source code, it generally starts from the entrance of the entire code, and the source code of the Ti ble protocol stack is no exception. Its main () function is the entry of the entire program, which is automatically called when the system powers on. It mainly does the following: (1) underlying hardware Initialization Configuration (2) create a task and initialize the task Configuration

# Sysctl-wNet. ipv4.conf. all. mc_forwarding=0 The OpenBSD3-4 is already the default setting Solaris8-10 # Ndd-set/dev/ip ip_forward_src_routed 0 # Ndd-set/dev/ip ip6_forward_src_routed 0 2. Sound force check, also known as entry filter or exit Filter Linux2.4-2.6 #sysctl-wnet.ipv4.conf.all.rp_filter=1 3. log and discard "Martian" packets Linux2.4-2.6 #sysctl-wnet.ipv4.conf.all.log_martians=1 The attack content of the IP

When looking at the source code, it generally starts from the entrance of the entire code, and the source code of the ti ble protocol stack is no exception. Its main () function is the entry of the entire program, which is automatically called when the system powers on. It mainly does the following: (1) underlying hardware Initialization Configuration (2) create a task and initialize the task Configuration

Reinforce the TCP/IP protocol stack by listing the registry values related to TCP/IP. You can configure these values on a computer directly connected to the Internet to reinforce the TCP/IP protocol stack. All these values are in the following registry key: HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services Not

Recently in the porting QQ IoT protocol, you need to read the device MAC address.Read the CC2541 device MAC address method, there is a direct read Mac register, you can also call the protocol stack API. This takes the form of a call API.1 /*use the protocol stack API to re

and TCP have the test that overwrites their header and data. UDP checks are optional, while TCP checks are required. Although the basic calculation method of UDP test is similar to the IP Address Header test and calculation method described in the preceding section (16-bit binary anticode and, but slightly different, some processing is added when the field type is determined to be UDP or TCP, and you can see the code), but there are differences between them. First, the UDP datagram length can b

Some of the things that have recently been written about network programming have encountered minor problems with transport. Because there is a simple look at some of the TCP/IP to explain some of the things, so simply find this "tracking LINUXTCP/IP code Run" book Read all morning, the results found that the first contact with these core aspects of things, harvest very little. And then on the Internet to find related categories of the Great God blog, to read, although still see is not too clear

Preface:Actually, this articleArticleI don't know what the name should be. I don't feel like I'm talking about anything. Alas... In fact, my intention is to describe the IP layer of the Linux protocol stack to route data packets. For example, if there are two Nic devices, where should the data packets go?And so on... First, understand the concept of routing cache:Although the data structure of route table

The core data structure of Linux network is socket buffer (skb. It represents a message to be sent or processed and runs through the entire protocol stack. 1. Socket Cache Skb consists of two parts: (1) packet data: It stores the data actually transmitted in the network; (2) management data: additional data for the kernel to process packets, which constitute control information exchanged between protocols.

Number 17, TCP protocol number 6, ICMP protocol number 114. ARP flood ARP requests are constantly sent, occupying Internet resources, and thus users cannot access the Internet. A little similar to DDoS x×x, causing the server to fail to work normally.15. ARP spoofing XXX (man-in-the-middle XXX) ××× Bind your Mac to A. The destination IP address of the ARP request sent to B is B. Bind the destination IP add

The lab's desktop is not on the network after the upgrade drive, the cable network card driver uninstalled after the reload, or not, through Windows diagnostics found that "Windows cannot automatically bind the IP protocol stack to the network adapter solution." Workaround: Open Control Panel >> Network and Internet >> Network Connections, right-click the network you want to view, select Properties, Unchec

mechanism, using the Sliding Window Algorithm, TCP can provide a congestion control and recovery mechanism, there are multiple TCP congestion control models. TCP can negotiate the length of data packets sent. TCP header. 0 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 4 5 6 7 8 9 0 1+- +-+| Source Port | Destination Port |+- +-+| Sequence Number |+- +-+| Acknowledgment Number |+- +-+| Data | U | A | P | R | S | F || Offset | Reserved | R | C | S | Y | I | Window || G | K | H | T | N |+- +-

dialog_initialize_rtp function to initialize the RTP information of the peer. Whether the peer has RTP. If yes, the encoding is set. When setting the RTP engine, it must be noted that the RTP protocol stack was greatly changed at the beginning of asterisk1.8. By default, the RTP protocol stack provided by asteirsk is

I. Summary The protocol stack used for TCP/IP implementation in the later version of The Altera software niosii (7.2 or later, which is used in this routine) is nichestack. There are two common routines, web_server and simple_socket_server.ArticleOnly describes the implementation process of simple_socket_server routine. Here, the driver of dm9000a is different from the Driver Based on LWIP in the previous

port number with a unique identity on the network can be combined to form a uniquely identifiable identifier socket. socket principle mechanism:? There are sockets on both ends of the communication. ? network communication is actually the communication between sockets. ? data is transmitted via IO between two sockets. UDP Transport Datagramsocket and Datagrampacket establish the sending end, the receiving end. set up the data package. invokes the Send receive method of th

, saddr, SIN->SIN_ADDR.S_ADDR, Skb->len-tmp, SK);//Calculate the checksum of the UDP header /* * Send the datagram to the interface. */ Udp_statistics. udpoutdatagrams++; Sk->prot->queue_xmit (SK, Dev, SKB, 1);//Call the IP layer function to send the data return (LEN); } This sends the data to the Sk_buff structure that is populated after the IP data header and the Mac frame header are added to the UDP packet. Finally, the Send function of the IP layer is called to send t

into the network protocol stack, complete route protocol stack. In step 2, if the MAC address corresponding to the destination IP address does not exist (or the next hop), arp_find is used to find the MAC address corresponding to the corresponding IP address. The general process is as follows: ARP will have an ARP c