if_tcp(7P) Protocols if_tcp(7P)NAME
if_tcp, if - general properties of Internet Protocol network interfaces
DESCRIPTION
A network interface is a device for sending and receiving packets on a
network. It is usually a hardware device, although it can be imple‐
mented in software. Network interfaces used by the Internet Protocol
(IPv4 or IPv6) must be STREAMS devices conforming to the Data Link
Provider Interface (DLPI). See dlpi(7P).
APPLICATION PROGRAMMING INTERFACE
An interface becomes available to IP when it is opened and the IP mod‐
ule is pushed onto the stream with the I_PUSH ioctl(2) command. (See
streamio(7I)). The SIOCSLIFNAME ioctl(2) is issued to specify the name
of the interface and to indicate whether it is IPv4 or IPv6. This may
be initiated by the kernel at boot time or by a user program after the
system is running. Each interface must be assigned an IP address with
the SIOCSLIFADDR ioctl() before it can be used. On interfaces where the
network-to-link layer address mapping is static, only the network num‐
ber is taken from the ioctl() request; the remainder is found in a
hardware specific manner. On interfaces which provide dynamic network-
to-link layer address mapping facilities (for example, 10Mb/s Ethernets
using arp(7P)), the entire address specified in the ioctl() is used. A
routing table entry for destinations on the network of the interface is
installed automatically when an interface's address is set.
IOCTLS
The following ioctl() calls may be used to manipulate IP network inter‐
faces. Unless specified otherwise, the request takes an lifreq struc‐
ture as its parameter. This structure has the form:
/* Interface request struct. used for socket ioctls. All */
/* interface ioctls must have parameter definitions which */
/* begin with lifr_name. The remainder may be interface specific. */
struct lifreq {
#define LIFNAMSIZ 32
char lifr_name[LIFNAMSIZ]; /* if name, e.g. "le1" */
union {
int lifru_addrlen; /* for subnet/token etc */
uint_t lifru_ppa; /* SIOCSLIFNAME */
} lifr_lifru1;
union {
struct sockaddr_storage lifru_addr;
struct sockaddr_storage lifru_dstaddr;
struct sockaddr_storage lifru_broadaddr;
struct sockaddr_storage lifru_token; /* With lifr_addrlen */
struct sockaddr_storage lifru_subnet; /* With lifr_addrlen */
int lifru_index; /* interface index */
uint64_t lifru_flags; /* SIOC?LIFFLAGS */
int lifru_metric;
uint_t lifru_mtu;
int lif_muxid[2]; /* mux id's for arp & ip */
struct lif_nd_req lifru_nd_req;
struct lif_ifinfo_req lifru_ifinfo_req;
zoneid_t lifru_zone; /* SIOC[GS]LIFZONE */
} lifr_lifru;
#define lifr_addrlen lifr_lifru1.lifru_addrlen
#define lifr_ppa lifr_lifru1.lifru_ppa /* Driver's ppa */
#define lifr_addr lifr_lifru.lifru_addr /* address */
#define lifr_dstaddr lifr_lifru.lifru_dstaddr
#define lifr_broadaddr lifr_lifru.lifru_broadaddr /* broadcast addr. */
#define lifr_token lifr_lifru.lifru_token /* address token */
#define lifr_subnet lifr_lifru.lifru_subnet /* subnet prefix */
#define lifr_index lifr_lifru.lifru_index /* interface index */
#define lifr_flags lifr_lifru.lifru_flags /* flags */
#define lifr_metric lifr_lifru.lifru_metric /* metric */
#define lifr_mtu lifr_lifru.lifru_mtu /* mtu */
#define lifr_index lifr_lifru.lifru_index /* interface index */
#define lifr_ip_muxid lifr_lifru.lif_muxid[0]
#define lifr_arp_muxid lifr_lifru.lif_muxid[1]
#define lifr_nd lifr_lifru.lifru_nd_req /* SIOCLIF*ND */
#define lifr_ifinfo lifr_lifru.lifru_ifinfo_req /* SIOC[GS]LIFLNKINFO */
#define lifr_zone lifr_lifru.lifru_zone /* SIOC[GS]LIFZONE */
};
SIOCSLIFADDR Set interface address. Following the address assign‐
ment, the "initialization" routine for the interface
is called.
SIOCGLIFADDR Get interface address.
SIOCSLIFDSTADDR Set point to point address for interface.
SIOCGLIFDSTADDR Get point to point address for interface.
SIOCSLIFFLAGS Set interface flags field. If the interface is
marked down, any processes currently routing packets
through the interface are notified.
SIOCGLIFFLAGS Get interface flags.
SIOCGLIFCONF Get interface configuration list. This request takes
an lifconf structure (see below) as a value-result
parameter. The lifc_family field can be set to
AF_UNSPEC to retrieve both AF_INET and AF_INET6
interfaces. The lifc_flags field should be set to
zero. The lifc_len field should be set to the size
of the buffer pointed to by lifc_buf. Upon success,
lifc_len will contain the length, in bytes, of the
array of lifreq structures pointed to by lifc_req.
For each lifreq structure, the lifr_name and
lifr_addr fields will be valid.
SIOCGLIFNUM Get number of interfaces. This request returns an
integer which is the number of interface descrip‐
tions (struct lifreq) that will be returned by the
SIOCGLIFCONF ioctl; that is, it gives an indication
of how large lifc_len has to be. This request takes
an lifnum structure (see below) as a value-result
parameter. The lifn_family field should be set to
AF_UNSPEC to count both AF_INET and AF_INET6 inter‐
faces. The lifn_flags field should be initially set
to zero.
SIOCSLIFMTU Set the maximum transmission unit (MTU) size for
interface. Place the result of this request in
lifru_mtu field. The MTU can not exceed the physical
MTU limitation (which is reported in the DLPI
DL_INFO_ACK message).
SIOCGLIFMTU Get the maximum transmission unit size for inter‐
face. Place the result of this request in ifru_mtu
field.
SIOCSLIFMETRIC Set the metric associated with the interface. The
metric is used by routing daemons such as
in.routed(1M).
SIOCGLIFMETRIC Get the metric associated with the interface.
SIOCGLIFMUXID Get the ip and arp muxid associated with the inter‐
face.
SIOCSLIFMUXID Set the ip and arp muxid associated with the inter‐
face.
SIOCGLIFINDEX Get the interface index associated with the inter‐
face.
SIOCSLIFINDEX Set the interface index associated with the inter‐
face.
SIOCGLIFZONE Get the zone associated with the interface.
SIOCSLIFZONE Set the zone associated with the interface. Only
applies for zones that use the shared-IP instance.
SIOCLIFADDIF Add a new logical interface on a physical interface
using an unused logical unit number. If the physical
interface is part of an IP multipathing group, the
logical interface may be added to a different physi‐
cal interface in the same group. Upon return, the
lifr_name field contains the name of the actual
logical interface created.
SIOCLIFREMOVEIF Remove a logical interface by specifying its IP
address or logical interface name. When the IP
address is specified and the interface is part of an
IP multipathing group, the logical interface is
removed from the physical interface in the group
which holds the IP address.
SIOCSLIFTOKEN Set the address token used to form IPv6 link-local
addresses and for stateless address autoconfigura‐
tion.
SIOCGLIFTOKEN Get the address token used to form IPv6 link-local
addresses and for stateless address autoconfigura‐
tion.
SIOCSLIFSUBNET Set the subnet prefix associated with the interface.
SIOCGLIFSUBNET Get the subnet prefix associated with the interface.
SIOCSLIFLNKINFO Set link specific parameters for the interface.
SIOCGLIFLNKINFO Get link specific parameters for the interface.
SIOCLIFDELND Delete a neighbor cache entry for IPv6.
SIOCLIFGETND Get a neighbor cache entry for IPv6.
SIOCLIFSETND Set a neighbor cache entry for IPv6.
SIOCTMYADDR Test if the address is assigned to this node. This
request takes an sioc_addrreq structure (see below)
as a value-result parameter. The sa_addr field
should be set to the address to test. The sa_res
field will contain a non-zero value if the address
is assigned to this node.
SIOCSLIFUSESRC Set the interface from which to choose a source
address. The lifr_index field has the interface
index corresponding to the interface whose address
is to be used as the source address for packets
going out on the interface whose name is provided by
lifr_name. If the lifr_index field is set to zero,
the previous setting is cleared. See ifconfig(1M)
for examples of the 'usesrc' option.
SIOCGLIFUSESRC Get the interface index of the interface whose
address is used as the source address for packets
going out on the interface provided by lifr_name
field. The value is retrieved in the lifr_index
field. See ifconfig(1M) for examples of the 'usesrc'
option.
SIOCGLIFSRCOF Get the interface configuration list for interfaces
that use an address hosted on the interface provided
by the lifs_ifindex field in the lifsrcof struct
(see below), as a source address. The application
sets lifs_maxlen to the size (in bytes) of the buf‐
fer it has allocated for the data. On return, the
kernel sets lifs_len to the actual size required.
Note, the application could set lifs_maxlen to zero
to query the kernel of the required buffer size
instead of estimating a buffer size. The application
tests 'lifs_len <= lifs_maxlen' -- if that's true,
the buffer was big enough and the application has an
accurate list. If it is false, it needs to allocate
a bigger buffer and try again, and lifs_len provides
a hint of how big to make the next trial. See ifcon‐
fig(1M) for examples of the 'usesrc' option.
The lifsrcof structure has the form:
/*
* Structure used in SIOCGLIFSRCOF to get interface
* configuration list for interfaces that use an
* address hosted on the interface (set in lifs_ifindex),
* as the source address.
*/
struct lifsrcof {
uint_t lifs_ifindex; /* addr on this interface*/
/* used as the src addr */
size_t lifs_maxlen; /* size of buffer: input */
size_t lifs_len; /* size of buffer: output */
union {
caddr_t lifsu_buf;
struct lifreq *lifsu_req;
} lifs_lifsu;
#define lifs_buf lifs_lifsu.lifsu_buf /* buffer addr. */
#define lifs_req lifs_lifsu.lifsu_req /* array returned */
};
SIOCTONLINK Test if the address is directly reachable, for exam‐
ple, that it can be reached without going through a
router. This request takes an sioc_addrreq structure
(see below) as a value-result parameter. The sa_addr
field should be set to the address to test. The
sa_res field will contain a non-zero value if the
address is onlink.
SIOCTMYSITE Test if the address is part of the same site as this
node. This request takes an sioc_addrreq structure
(see below) as a value-result parameter. The sa_addr
field should be set to the address to test. The
sa_res field will contain a non-zero value if the
address is in the same site.
The lifconf structure has the form:
/*
/* Structure used in SIOCGLIFCONF request. */
struct lifconf {
sa_family_t lifc_family;
int lifc_flags; /* req. specific interfaces */
int lifc_len; /* size of assoc. buffer */
union {
caddr_t lifcu_buf;
struct lifreq *lifcu_req;
} lifc_lifcu;
#define lifc_buf lifc_lifcu.lifcu_buf /* buffer address */
#define lifc_req lifc_lifcu.lifcu_req /* array of structs returned */
};
/* Structure used in SIOCGLIFNUM request. */
struct lifnum {
sa_family_t lifn_family;
int lifn_flags; /* req. specific interfaces */
int lifn_count; /* Result */
};
The sioc_addrreq structure has the form:
/*
* Argument structure for SIOCT* address testing ioctls.
*/
struct sioc_addrreq {
struct sockaddr_storage sa_addr; /* Address to test */
int sa_res; /* Result - 0/1 */
};
The following ioctl() calls are maintained for compatibility but only
apply to IPv4 network interfaces, since the data structures are too
small to hold an IPv6 address. Unless specified otherwise, the request
takes an ifreq structure as its parameter. This structure has the form:
/* Interface request structure used for socket ioctls. All */
/* interface ioctls must have parameter definitions which */
/* begin with lifr_name. The remainder may be interface specific. */
struct ifreq {
#define IFNAMSIZ 16
char ifr_name[IFNAMSIZ]; /* interface name - e.g. "hme0" */
union {
struct sockaddr ifru_addr;
struct sockaddr ifru_dstaddr;
struct sockaddr ifru_broadaddr;
short ifru_flags;
int ifru_metric;
int if_muxid[2]; /* mux id's for arp and ip */
int ifru_index; /* interface index */
} ifr_ifru;
#define ifr_addr ifr_ifru.ifru_addr /* address */
#define ifr_dstaddr ifr_ifru.ifru_dstaddr /* other end of p-to-p link */
#define ifr_broadaddr ifr_ifru.ifru_broadaddr /* broadcast address */
#define ifr_flags ifr_ifru.ifru_flags /* flags */
#define ifr_index ifr_ifru.ifru_index /* interface index */
#define ifr_metric ifr_ifru.ifru_metric /* metric */
};
SIOCSIFADDR Set interface address. Following the address assign‐
ment, the "initialization" routine for the interface
is called.
SIOCGIFADDR Get interface address.
SIOCSIFDSTADDR Set point to point address for interface.
SIOCGIFDSTADDR Get point to point address for interface.
SIOCSIFFLAGS Set interface flags field. If the interface is marked
down, any processes currently routing packets through
the interface are notified.
SIOCGIFFLAGS Get interface flags.
SIOCGIFCONF Get interface configuration list. This request takes
an ifconf structure (see below) as a value-result
parameter. The ifc_len field should be set to the
size of the buffer pointed to by ifc_buf. Upon suc‐
cess, ifc_len will contain the length, in bytes, of
the array of ifreq structures pointed to by ifc_req.
For each ifreq structure, the ifr_name and ifr_addr
fields will be valid.
SIOCGIFNUM Get number of interfaces. This request returns an
integer which is the number of interface descriptions
(struct ifreq) that will be returned by the SIOCGIF‐
CONF ioctl; that is, it gives an indication of how
large ifc_len has to be.
SIOCSIFMTU Set the maximum transmission unit (MTU) size for
interface. Place the result of this request in
ifru_metric field. The MTU has to be smaller than
physical MTU limitation (which is reported in the
DLPI DL_INFO_ACK message).
SIOCGIFMTU Get the maximum transmission unit size for interface.
Place the result of this request in ifru_metric
field.
SIOCSIFMETRIC Set the metric associated with the interface. The
metric is used by routine daemons such as
in.routed(1M).
SIOCGIFMETRIC Get the metric associated with the interface.
SIOCGIFMUXID Get the ip and arp muxid associated with the inter‐
face.
SIOCSIFMUXID Set the ip and arp muxid associated with the inter‐
face.
SIOCGIFINDEX Get the interface index associated with the inter‐
face.
SIOCSIFINDEX Set the interface index associated with the inter‐
face.
The ifconf structure has the form:
/*
* Structure used in SIOCGIFCONF request.
* Used to retrieve interface configuration
* for machine (useful for programs which
* must know all networks accessible).
*/
struct ifconf {
int ifc_len; /* size of assoc. buffer */
union {
caddr_t ifcu_buf;
struct ifreq *ifcu_req;
} ifc_ifcu;
#define ifc_buf ifc_ifcu.ifcu_buf /* buffer address */
#define ifc_req ifc_ifcu.ifcu_req /* array of structs returned */
};
IFF_ Flags
To display addressing information for each interface, enter ifconfig
-a. IFF_ flags are defined in /usr/include/net/if.h. The flags are:
#define IFF_UP 0x00000001 /* Interface is up */
#define IFF_BROADCAST 0x00000002 /* Broadcast address valid */
#define IFF_DEBUG 0x00000004 /* Turn on debugging */
#define IFF_LOOPBACK 0x00000008 /* Loopback net */
#define IFF_POINTOPOINT 0x00000010 /* Interface is point-to-point link */
#define IFF_NOTRAILERS 0x00000020 /* Avoid use of trailers */
#define IFF_RUNNING 0x00000040 /* Resources allocated */
#define IFF_NOARP 0x00000080 /* No address res. protocol */
#define IFF_PROMISC 0x00000100 /* Receive all packets */
#define IFF_ALLMULTI 0x00000200 /* Receive all multicast pkts */
#define IFF_INTELLIGENT 0x00000400 /* Protocol code on board */
#define IFF_MULTICAST 0x00000800 /* Supports multicast */
#define IFF_MULTI_BCAST 0x00001000 /* Multicast using broadcast add. */
#define IFF_UNNUMBERED 0x00002000 /* Non-unique address */
#define IFF_DHCPRUNNING 0x00004000 /* DHCP controls interface */
#define IFF_PRIVATE 0x00008000 /* Do not advertise */
#define IFF_NOXMIT 0x00010000 /* Do not transmit pkts */
#define IFF_NOLOCAL 0x00020000 /* No address - just on-link subnet */
#define IFF_DEPRECATED 0x00040000 /* Interface addr. deprecated */
#define IFF_ADDRCONF 0x00080000 /* Addr. from stateless addrconf */
#define IFF_ROUTER 0x00100000 /* Router on interface */
#define IFF_NONUD 0x00200000 /* No NUD on interface */
#define IFF_ANYCAST 0x00400000 /* Anycast address */
#define IFF_NORTEXCH 0x00800000 /* Don't exchange routing info */
#define IFF_IPV4 0x01000000 /* IPv4 interface */
#define IFF_IPV6 0x02000000 /* IPv6 interface */
#define IFF_MIPRUNNING 0x04000000 /* Mobile IP controls interface */
#define IFF_NOFAILOVER 0x008000000 /* Don't failover on NIC failure */
#define IFF_FAILED 0x010000000 /* NIC has failed */
#define IFF_STANDBY 0x020000000 /* Standby NIC-use on failures */
#define IFF_INACTIVE 0x040000000 /* Standby active or not? */
#define IFF_OFFLINE 0x080000000 /* NIC offlined */
#define IFF_XRESOLV 0x100000000 /* IPv6 external resolver */
#define IFF_COS_ENABLED 0x200000000 /* If CoS marking is supported */
#define IFF_PREFERRED 0x400000000 /* Prefer as source address */
#define IFF_TEMPORARY 0x800000000 /* RFC3041 */
#define IFF_FIXEDMTU 0x1000000000 /* MTU set with SIOCSLIFMTU */
#define IFF_VIRTUAL 0x2000000000 /* Cannot send/receive pkts */
#define IFF_DUPLICATE 0x4000000000 /* Local address in use */
For more information on IFF_ flags, see ifconfig(1M).
ERRORS
EPERM The effective user id of the calling process in not supe‐
ruser.
ENXIO The lifr_name member of the lifreq structure contains an
invalid value.
For SIOCGLIFSRCOF, the lifs_ifindex member of the lifsrcof
structure contains an invalid value.
For SIOCSLIFUSESRC, this error is returned if the
lifr_index is set to an invalid value.
EBADADDR Wrong address family or malformed address.
EINVAL For SIOCSLIFMTU, this error is returned when the requested
MTU size is invalid. This error indicates the MTU size is
greater than the MTU size supported by the DLPI provider or
less than 68 (for IPv4 ) or less than 1200 (for IPv6 ). ]
For SIOCSLIFUSESRC, this error is returned if either the
lifr_index or lifr_name identify interfaces that are
already part of an existing IPMP group.
EEXIST For SIOCLIFADDIF, this error is rifeturned if the lifr_name
member in the lifreq structure corresponds to an interface
that already has the PPA specified by lifru_ppa plumbed.
SEE ALSOifconfig(1M), in.routed(1M), ioctl(2), streamio(7I), arp(7P), dlpi(7P),
ip(7P), ip6(7P)SunOS 5.10 31 May 2010 if_tcp(7P)
