There are a set of socket calls that can be done on an interface using the ioctl function. I have written a few articles about interacting with an interface via socket and ioctl calls which you can check out here:

You will notice that each ioctl call uses some defines such as SIOCGIFADDR and SIOCSIFHWADDR to name a few. I suppose the question is, how do you know which parameter is required for each action? And where can I find the entire list of options? I think the first time I attempted doing an interface modification I had to bring an interface up or down based on some circumstances, but had no idea how to do it. I found some arbitrary code that referenced these odd defines. I went all out and did a:

$ find / -print | xargs grep "SIOCGIFADDR"

I waited about 30 mins and came back to my computer. In hindsight I should have just looked at all the includes in the code example and see if there is more information within them related to these ioctl calls.

The ioctl calls I am using interface with a socket file descriptor, the ioctl call is actually a generic interface to any device type as long as those interfaces are defined in their respective kernel code. This article gives a basic rundown of using ioctl. Another piece to look at is the kernel code for the driver which defines the ioctl available interfaces. But I digress.

I would like to include the list of the socket-level I/O control calls as defined in linux/sockios.h.

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/* Linux-specific socket ioctls */
#define SIOCINQ		FIONREAD
#define SIOCOUTQ	TIOCOUTQ
 
/* Routing table calls. */
#define SIOCADDRT	0x890B		/* add routing table entry	*/
#define SIOCDELRT	0x890C		/* delete routing table entry	*/
#define SIOCRTMSG	0x890D		/* call to routing system	*/
 
/* Socket configuration controls. */
#define SIOCGIFNAME	0x8910		/* get iface name		*/
#define SIOCSIFLINK	0x8911		/* set iface channel		*/
#define SIOCGIFCONF	0x8912		/* get iface list		*/
#define SIOCGIFFLAGS	0x8913		/* get flags			*/
#define SIOCSIFFLAGS	0x8914		/* set flags			*/
#define SIOCGIFADDR	0x8915		/* get PA address		*/
#define SIOCSIFADDR	0x8916		/* set PA address		*/
#define SIOCGIFDSTADDR	0x8917		/* get remote PA address	*/
#define SIOCSIFDSTADDR	0x8918		/* set remote PA address	*/
#define SIOCGIFBRDADDR	0x8919		/* get broadcast PA address	*/
#define SIOCSIFBRDADDR	0x891a		/* set broadcast PA address	*/
#define SIOCGIFNETMASK	0x891b		/* get network PA mask		*/
#define SIOCSIFNETMASK	0x891c		/* set network PA mask		*/
#define SIOCGIFMETRIC	0x891d		/* get metric			*/
#define SIOCSIFMETRIC	0x891e		/* set metric			*/
#define SIOCGIFMEM	0x891f		/* get memory address (BSD)	*/
#define SIOCSIFMEM	0x8920		/* set memory address (BSD)	*/
#define SIOCGIFMTU	0x8921		/* get MTU size			*/
#define SIOCSIFMTU	0x8922		/* set MTU size			*/
#define SIOCSIFNAME	0x8923		/* set interface name */
#define	SIOCSIFHWADDR	0x8924		/* set hardware address 	*/
#define SIOCGIFENCAP	0x8925		/* get/set encapsulations       */
#define SIOCSIFENCAP	0x8926		
#define SIOCGIFHWADDR	0x8927		/* Get hardware address		*/
#define SIOCGIFSLAVE	0x8929		/* Driver slaving support	*/
#define SIOCSIFSLAVE	0x8930
#define SIOCADDMULTI	0x8931		/* Multicast address lists	*/
#define SIOCDELMULTI	0x8932
#define SIOCGIFINDEX	0x8933		/* name -> if_index mapping	*/
#define SIOGIFINDEX	SIOCGIFINDEX	/* misprint compatibility :-)	*/
#define SIOCSIFPFLAGS	0x8934		/* set/get extended flags set	*/
#define SIOCGIFPFLAGS	0x8935
#define SIOCDIFADDR	0x8936		/* delete PA address		*/
#define	SIOCSIFHWBROADCAST	0x8937	/* set hardware broadcast addr	*/
#define SIOCGIFCOUNT	0x8938		/* get number of devices */
 
#define SIOCGIFBR	0x8940		/* Bridging support		*/
#define SIOCSIFBR	0x8941		/* Set bridging options 	*/
 
#define SIOCGIFTXQLEN	0x8942		/* Get the tx queue length	*/
#define SIOCSIFTXQLEN	0x8943		/* Set the tx queue length 	*/
 
/* SIOCGIFDIVERT was:	0x8944		Frame diversion support */
/* SIOCSIFDIVERT was:	0x8945		Set frame diversion options */
 
#define SIOCETHTOOL	0x8946		/* Ethtool interface		*/
 
#define SIOCGMIIPHY	0x8947		/* Get address of MII PHY in use. */
#define SIOCGMIIREG	0x8948		/* Read MII PHY register.	*/
#define SIOCSMIIREG	0x8949		/* Write MII PHY register.	*/
 
#define SIOCWANDEV	0x894A		/* get/set netdev parameters	*/
 
/* ARP cache control calls. */
		    /*  0x8950 - 0x8952  * obsolete calls, don't re-use */
#define SIOCDARP	0x8953		/* delete ARP table entry	*/
#define SIOCGARP	0x8954		/* get ARP table entry		*/
#define SIOCSARP	0x8955		/* set ARP table entry		*/
 
/* RARP cache control calls. */
#define SIOCDRARP	0x8960		/* delete RARP table entry	*/
#define SIOCGRARP	0x8961		/* get RARP table entry		*/
#define SIOCSRARP	0x8962		/* set RARP table entry		*/
 
/* Driver configuration calls */
 
#define SIOCGIFMAP	0x8970		/* Get device parameters	*/
#define SIOCSIFMAP	0x8971		/* Set device parameters	*/
 
/* DLCI configuration calls */
 
#define SIOCADDDLCI	0x8980		/* Create new DLCI device	*/
#define SIOCDELDLCI	0x8981		/* Delete DLCI device		*/
 
#define SIOCGIFVLAN	0x8982		/* 802.1Q VLAN support		*/
#define SIOCSIFVLAN	0x8983		/* Set 802.1Q VLAN options 	*/
 
/* bonding calls */
 
#define SIOCBONDENSLAVE	0x8990		/* enslave a device to the bond */
#define SIOCBONDRELEASE 0x8991		/* release a slave from the bond*/
#define SIOCBONDSETHWADDR      0x8992	/* set the hw addr of the bond  */
#define SIOCBONDSLAVEINFOQUERY 0x8993   /* rtn info about slave state   */
#define SIOCBONDINFOQUERY      0x8994	/* rtn info about bond state    */
#define SIOCBONDCHANGEACTIVE   0x8995   /* update to a new active slave */
 
/* bridge calls */
#define SIOCBRADDBR     0x89a0		/* create new bridge device     */
#define SIOCBRDELBR     0x89a1		/* remove bridge device         */
#define SIOCBRADDIF	0x89a2		/* add interface to bridge      */
#define SIOCBRDELIF	0x89a3		/* remove interface from bridge */
 
/* hardware time stamping: parameters in linux/net_tstamp.h */
#define SIOCSHWTSTAMP   0x89b0
 
/* Device private ioctl calls */
 
/*
 *	These 16 ioctls are available to devices via the do_ioctl() device
 *	vector. Each device should include this file and redefine these names
 *	as their own. Because these are device dependent it is a good idea
 *	_NOT_ to issue them to random objects and hope.
 *
 *	THESE IOCTLS ARE _DEPRECATED_ AND WILL DISAPPEAR IN 2.5.X -DaveM
 */
 
#define SIOCDEVPRIVATE	0x89F0	/* to 89FF */

Now the table is here for easy perusal. But what do these hex values really mean? These values refer to request information that the kernel device driver code will present back to the userspace application. In my earlier articles I use a few of these defines to retrieve interface information like name and interface index. I would suggest trying out a few of these calls, try adding a route with SIOCADDRT.

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