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:
- Set an IP address from a C process to your interface.
- Get the interfaces index number.
- Retrieve an interfaces MAC address from your C process.
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.