c Archives - BinaryTides https://www.binarytides.com/tag/c/ News, Technology, Entertainment and more Mon, 10 Aug 2020 11:07:12 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.2 C Program to get MAC Address from Interface Name on Linux https://www.binarytides.com/c-program-to-get-mac-address-from-interface-name-on-linux/ https://www.binarytides.com/c-program-to-get-mac-address-from-interface-name-on-linux/#comments Sat, 17 Mar 2012 14:00:25 +0000 http://www.binarytides.com/blog/?p=1466 MAC Address The mac address (media access control address) or the hardware address or the ethernet address of an interface is a 48 bit number that looks like this : 00:1c:c0:f8:79:ee. Every machine connected to a network has a unique mac address that is used to deliver network packets to the correct machine. The mac... Read More »

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]]> https://www.binarytides.com/c-program-to-get-mac-address-from-interface-name-on-linux/feed/ 4 C Program to Get IP Address from Interface Name on Linux https://www.binarytides.com/c-program-to-get-ip-address-from-interface-name-on-linux/ https://www.binarytides.com/c-program-to-get-ip-address-from-interface-name-on-linux/#comments Sat, 17 Mar 2012 13:51:16 +0000 http://www.binarytides.com/blog/?p=1462 On a Linux system, all network interfaces have a unique name that is shows up when you run the ifconfig command for example. The main network adapter often has the name eth0 or enp1s0 on linux systems. The ip address is configured using desktop gui tools, or through commands like ifconfig. If you are writing... Read More »

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]]> https://www.binarytides.com/c-program-to-get-ip-address-from-interface-name-on-linux/feed/ 4 Get time difference in microtime in C https://www.binarytides.com/get-time-difference-in-microtime-in-c/ https://www.binarytides.com/get-time-difference-in-microtime-in-c/#comments Fri, 09 Mar 2012 12:06:54 +0000 http://www.binarytides.com/blog/?p=1417 The function gettimeofday can be used to retrieve the total number of seconds and balance microseconds elapsed since EPOCH. Structure timeval looks like this : struct timeval { time_t tv_sec; /* seconds */ suseconds_t tv_usec; /* microseconds */ }; On Linux it can be done like this : /** * Get time difference in microseconds... Read More »

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]]> https://www.binarytides.com/get-time-difference-in-microtime-in-c/feed/ 1 Data type u_int8_t , u_int16_t , u_int32_t on windows https://www.binarytides.com/data-type-u_int8_t-u_int16_t-u_int32_t-on-windows/ https://www.binarytides.com/data-type-u_int8_t-u_int16_t-u_int32_t-on-windows/#respond Fri, 09 Mar 2012 06:36:41 +0000 http://www.binarytides.com/blog/?p=1414 On Linux the header file sys/types.h provides the fixed sized integer data types like these : u_int8_t; u_int16_t; u_int32_t; On windows the header file stdint.h provides similar ones but with slightly different names , uint8_t etc. So if you are writing cross platform code you can get the same ones on windows as in a... Read More »

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]]> https://www.binarytides.com/data-type-u_int8_t-u_int16_t-u_int32_t-on-windows/feed/ 0 How to Get IP Whois Data in C with Sockets on Linux – Code Example https://www.binarytides.com/c-code-to-perform-ip-whois/ https://www.binarytides.com/c-code-to-perform-ip-whois/#respond Thu, 16 Feb 2012 06:11:41 +0000 http://www.binarytides.com/blog/?p=1396 Theory The whois information of an ip address provides various details like its network, range, isp etc. This information is maintained by various regional registry servers. Read the wikipedia article on regional internet registries for more information. There are a total of 5 regional registries spanning various geographical regions of the world. For example if... Read More »

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]]> https://www.binarytides.com/c-code-to-perform-ip-whois/feed/ 0 Handle multiple socket connections with fd_set and select on Linux https://www.binarytides.com/multiple-socket-connections-fdset-select-linux/ https://www.binarytides.com/multiple-socket-connections-fdset-select-linux/#comments Sun, 25 Dec 2011 14:20:51 +0000 http://www.binarytides.com/blog/?p=1297 Handle multiple socket connections When writing server programs using sockets , it becomes necessary to handle multiple connections at a time , since a server needs to serve multiple clients. There are many ways to do so. On linux this can be done in various ways like forking , threading , select method etc. In... Read More »

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]]> https://www.binarytides.com/multiple-socket-connections-fdset-select-linux/feed/ 31 How to Get Domain Whois Data in C with Sockets on Linux – Code Example https://www.binarytides.com/whois-client-code-in-c-with-linux-sockets/ https://www.binarytides.com/whois-client-code-in-c-with-linux-sockets/#comments Fri, 23 Dec 2011 06:47:17 +0000 http://www.binarytides.com/blog/?p=1266 Whois A whois client is a program that will simply fetch the whois information for a domain/ip address from the whois servers. The code over here works according to the algorithm discussed here. A whois server runs a whois service on port 43 (whois port). We need to connect to this port with sockets and... Read More »

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]]> https://www.binarytides.com/whois-client-code-in-c-with-linux-sockets/feed/ 4 str_replace for C https://www.binarytides.com/str_replace-for-c/ https://www.binarytides.com/str_replace-for-c/#comments Thu, 22 Dec 2011 12:33:25 +0000 http://www.binarytides.com/blog/?p=1262 Php has a useful function called str_replace which can search and replace a certain string in another big string. However there is no such function in C. So I wrote up one for myself. Here is the code. /* * Search and replace a string with another string , in a string * */ char... Read More »

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]]> https://www.binarytides.com/str_replace-for-c/feed/ 3 How to Get Local IP in C using sockets on Linux https://www.binarytides.com/get-local-ip-c-linux/ https://www.binarytides.com/get-local-ip-c-linux/#comments Tue, 20 Dec 2011 06:41:04 +0000 http://www.binarytides.com/blog/?p=1248 Local Ip address The local ip is the source ip in IP packets send out from a system. When the system is a part of a local area network then the local ip in most cases is something like 192.168.*.* . The network interface (eth0) is assigned an ip address of that range. However when... Read More »

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]]> https://www.binarytides.com/get-local-ip-c-linux/feed/ 3 How to Code a Packet Sniffer in C with Winpcap https://www.binarytides.com/code-packet-sniffer-c-winpcap/ https://www.binarytides.com/code-packet-sniffer-c-winpcap/#comments Sun, 18 Dec 2011 11:15:43 +0000 http://www.binarytides.com/blog/?p=1244 Winpcap Winpcap is a packet capture library for Windows used for packet sniffing and sending raw packets. Wireshark is a popular sniffer tool that uses winpcap to sniff packets. Here is a sample code which shows how winpcap can be used to sniff incoming packets on a particular interface. Code /* Simple Sniffer with winpcap... Read More »

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]]> https://www.binarytides.com/code-packet-sniffer-c-winpcap/feed/ 15 How to get MAC address from ip in winsock https://www.binarytides.com/get-mac-address-from-ip-in-winsock/ https://www.binarytides.com/get-mac-address-from-ip-in-winsock/#comments Fri, 16 Dec 2011 09:55:06 +0000 http://www.binarytides.com/blog/?p=1235 MAC Address Mac address (Media Access Control Address) or hardware address is a 48 bit (6 character) wide address assigned to a network interface. It is important for the packet delivery between 2 devices like your computer and the router. Ethernet protocol uses the mac address to deliver it to the right network node. It... Read More »

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]]> https://www.binarytides.com/get-mac-address-from-ip-in-winsock/feed/ 4 How to code a Packet Sniffer in C with Linux Sockets – Part 2 https://www.binarytides.com/packet-sniffer-code-in-c-using-linux-sockets-bsd-part-2/ https://www.binarytides.com/packet-sniffer-code-in-c-using-linux-sockets-bsd-part-2/#comments Thu, 01 Dec 2011 12:27:46 +0000 http://www.binarytides.com/blog/?p=1045 In the previous part we made a simple sniffer which created a raw socket and started receiving on it. But it had few drawbacks : 1. Could sniff only incoming data. 2. Could sniff only TCP or UDP or ICMP or any one protocol packets at a time. 3. Ethernet headers were not available. In... Read More »

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]]> https://www.binarytides.com/packet-sniffer-code-in-c-using-linux-sockets-bsd-part-2/feed/ 71 DNS Query Code in C with Linux sockets https://www.binarytides.com/dns-query-code-in-c-with-linux-sockets/ https://www.binarytides.com/dns-query-code-in-c-with-linux-sockets/#comments Fri, 21 Oct 2011 11:28:11 +0000 http://www.binarytides.com/blog/?p=515 DNS Query Code in C A dns query lets you to lookup the various dns records for a given hostname or domain name on the internet. The simplest use case is to lookup the ip address of a domain name. When you open a url in your browser, it first performs a dns query to... Read More »

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]]> https://www.binarytides.com/dns-query-code-in-c-with-linux-sockets/feed/ 12 How to Code Raw Sockets in C on Linux https://www.binarytides.com/raw-sockets-c-code-linux/ https://www.binarytides.com/raw-sockets-c-code-linux/#comments Tue, 05 May 2009 23:25:00 +0000 http://www.binarytides.com/blog/?p=60 Raw tcp sockets in C Raw sockets can be used to construct a packet manually inside an application. In normal sockets when any data is send over the network, the kernel of the operating system adds some headers to it like IP header and TCP header. So an application only needs to take care of... Read More »

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]]> https://www.binarytides.com/raw-sockets-c-code-linux/feed/ 39 How to code a SYN Flood DOS attack program in C on Linux https://www.binarytides.com/syn-flood-dos-attack/ https://www.binarytides.com/syn-flood-dos-attack/#comments Sun, 03 May 2009 03:28:00 +0000 http://www.binarytides.com/blog/?p=59 TCP/IP 3-way handshake is done to establish a connection between a client and a server. The process is : 1. Client --SYN Packet--> Server 2. Server --SYN/ACK Packet --> Client 3. Client --ACK Packet --> Server The above 3 steps are followed to establish a connection between source and destination. SYN Flood DOS attacks involves... Read More »

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]]> https://www.binarytides.com/syn-flood-dos-attack/feed/ 98 How to code a TCP Connect Port Scanner in C with Winsock https://www.binarytides.com/tcp-connect-port-scanner-code-c-winsock/ https://www.binarytides.com/tcp-connect-port-scanner-code-c-winsock/#comments Thu, 30 Apr 2009 10:16:00 +0000 http://www.binarytides.com/blog/?p=52 Tcp connect port scanning TCP connect() scanning is the most basic form of TCP scanning. The program performs a connect() command on those ports of the target machine which are to be checked. If the port is open then the connect() command will succeed and a connection will be established. If the port is closed... Read More »

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]]> https://www.binarytides.com/tcp-connect-port-scanner-code-c-winsock/feed/ 2 How to Code a Port Scanner in C on Linux https://www.binarytides.com/tcp-connect-port-scanner-c-code-linux-sockets/ https://www.binarytides.com/tcp-connect-port-scanner-c-code-linux-sockets/#comments Tue, 28 Apr 2009 17:24:00 +0000 http://www.binarytides.com/blog/?p=51 Port scanning A port scanner is a program that checks for open network ports on a local or remote machine. For example, if a machine is running an http webserver then it has port 80 open. So by scanning for open ports on a machine, we can find what server applications are running on it.... Read More »

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]]> https://www.binarytides.com/tcp-connect-port-scanner-c-code-linux-sockets/feed/ 3 Raw socket programming on windows with Winpcap https://www.binarytides.com/raw-sockets-packets-with-winpcap/ https://www.binarytides.com/raw-sockets-packets-with-winpcap/#comments Sun, 13 Jan 2008 04:26:00 +0000 http://www.binarytides.com/blog/?p=20 Raw sockets with winpcap A previous post explains how to send on windows xp. However the winsock api has limited raw socket support in windows versions greater than windows xp+sp1. Therefore winpcap has to be used to send raw packets on higher windows versions. Winpcap is a packet driver useful for packet capturing and sending... Read More »

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]]> https://www.binarytides.com/raw-sockets-packets-with-winpcap/feed/ 22 DNS Query Code in C with winsock https://www.binarytides.com/dns-query-code-in-c-with-winsock/ https://www.binarytides.com/dns-query-code-in-c-with-winsock/#comments Mon, 19 Mar 2007 12:03:00 +0000 http://www.binarytides.com/blog/?p=7 DNS Query When we type a web url or domain in our browser a dns request is immediately send by our browser to a DNS server to get the IP address of that web address. In winsock applications we achieve this by gethostbyname() and things are pretty simple. In this article we shall do this... Read More »

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]]> https://www.binarytides.com/dns-query-code-in-c-with-winsock/feed/ 51 How to code a Packet Sniffer in C using Winsock https://www.binarytides.com/packet-sniffer-code-in-c-using-winsock/ https://www.binarytides.com/packet-sniffer-code-in-c-using-winsock/#comments Mon, 19 Mar 2007 11:51:00 +0000 http://www.binarytides.com/blog/?p=6 Winsock packet sniffer A packet sniffer is a program that can sniff the packets moving on the network. All applications communicate over the network with data packets where each packet contains part of the whole data being exchanged. A sniffer is able to pickup these individual packets and read them. In this post we are... Read More »

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