-.TH NETINTRO 4 ""
-.UC 5
-.SH NAME
-networking \- introduction to networking facilities
-.SH SYNOPSIS
-.nf
-.ft B
-#include <sys/socket.h>
-#include <net/route.h>
-#include <net/if.h>
-.fi R
-.fi
-.SH DESCRIPTION
-.de _d
-.if t .ta .6i 2.1i 2.6i
-.\" 2.94 went to 2.6, 3.64 to 3.30
-.if n .ta .84i 2.6i 3.30i
-..
-.de _f
-.if t .ta .5i 1.25i 2.5i
-.\" 3.5i went to 3.8i
-.if n .ta .7i 1.75i 3.8i
-..
+.Dd
+.Dt NETINTRO 4
+.Os BSD 4.2
+.Sh NAME
+.Nm networking
+.Nd introduction to networking facilities
+.Sh SYNOPSIS
+.Fd #include <sys/socket.h>
+.Fd #include <net/route.h>
+.Fd #include <net/if.h>
+.Sh DESCRIPTION
This section is a general introduction to the networking facilities
available in the system.
Documentation in this part of section
4 is broken up into three areas:
This section is a general introduction to the networking facilities
available in the system.
Documentation in this part of section
4 is broken up into three areas:
-.IR "network interfaces" .
-.\" Entries describing a protocol family are marked ``4F,''
-.\" while entries describing protocol use are marked ``4P.''
-.\" Hardware support for network interfaces are found
-.\" among the standard ``4'' entries.
-.PP
+.Em network interfaces .
+.Pp
A protocol family provides basic services to the protocol
implementation to allow it to function within a specific
network environment. These services may include
A protocol family provides basic services to the protocol
implementation to allow it to function within a specific
network environment. These services may include
methods of addressing, though the current protocol implementations
do not. A protocol family is normally comprised of a number
of protocols, one per
methods of addressing, though the current protocol implementations
do not. A protocol family is normally comprised of a number
of protocols, one per
type. It is not required that a protocol family support
all socket types. A protocol family may contain multiple
protocols supporting the same socket abstraction.
type. It is not required that a protocol family support
all socket types. A protocol family may contain multiple
protocols supporting the same socket abstraction.
A specific protocol may be accessed either by creating a
socket of the appropriate type and protocol family, or
by requesting the protocol explicitly when creating a socket.
A specific protocol may be accessed either by creating a
socket of the appropriate type and protocol family, or
by requesting the protocol explicitly when creating a socket.
the basic model for their particular socket type, but may,
in addition, provide non-standard facilities or extensions
to a mechanism. For example, a protocol supporting the
the basic model for their particular socket type, but may,
in addition, provide non-standard facilities or extensions
to a mechanism. For example, a protocol supporting the
abstraction may allow more than one byte of out-of-band
data to be transmitted per out-of-band message.
abstraction may allow more than one byte of out-of-band
data to be transmitted per out-of-band message.
A network interface is similar to a device interface.
Network interfaces comprise the lowest layer of the
networking subsystem, interacting with the actual transport
A network interface is similar to a device interface.
Network interfaces comprise the lowest layer of the
networking subsystem, interacting with the actual transport
entry gives a sample specification
of the related drivers for use in providing
a system description to the
entry gives a sample specification
of the related drivers for use in providing
a system description to the
program.
The DIAGNOSTICS section lists messages which may appear on the console
and/or in the system error log,
program.
The DIAGNOSTICS section lists messages which may appear on the console
and/or in the system error log,
-and some of the ISO OSI protocols.
-Raw socket interfaces are provided to the IP protocol
-layer of the DARPA Internet, to the IMP link layer (1822), and to
-the IDP protocol of Xerox NS.
+and some of the
+.Tn ISO OSI
+protocols.
+Raw socket interfaces are provided to the
+.Tn IP
+protocol
+layer of the
+.Tn DARPA
+Internet, to the
+.Tn IMP
+link layer (1822), and to
+the
+.Tn IDP
+protocol of Xerox
+.Tn NS .
Consult the appropriate manual pages in this section for more
information regarding the support for each protocol family.
Consult the appropriate manual pages in this section for more
information regarding the support for each protocol family.
Associated with each protocol family is an address
format. All network address adhere to a general structure,
called a sockaddr, described below. However, each protocol
imposes finer and more specific structure, generally renaming
the variant, which is discussed in the protocol family manual
page alluded to above.
Associated with each protocol family is an address
format. All network address adhere to a general structure,
called a sockaddr, described below. However, each protocol
imposes finer and more specific structure, generally renaming
the variant, which is discussed in the protocol family manual
page alluded to above.
-.sp 1
-.nf
-._d
-#define AF_UNIX 1 /* local to host (pipes, portals) */
-#define AF_INET 2 /* internetwork: UDP, TCP, etc. */
-#define AF_IMPLINK 3 /* arpanet imp addresses */
-#define AF_NS 6 /* Xerox NS protocols */
-#define AF_CCITT 10 /* CCITT protocols, X.25 etc */
-#define AF_HYLINK 15 /* NSC Hyperchannel */
-#define AF_ISO 18 /* ISO protocols */
-.fi
-.SH ROUTING
-.PP
-.UX
+.Bd -literal
+#define AF_UNIX 1 /* local to host (pipes, portals) */
+#define AF_INET 2 /* internetwork: UDP, TCP, etc. */
+#define AF_IMPLINK 3 /* arpanet imp addresses */
+#define AF_NS 6 /* Xerox NS protocols */
+#define AF_CCITT 10 /* CCITT protocols, X.25 etc */
+#define AF_HYLINK 15 /* NSC Hyperchannel */
+#define AF_ISO 18 /* ISO protocols */
+.Ed
+.Sh ROUTING
+.Tn UNIX
provides some packet routing facilities.
The kernel maintains a routing information database, which
is used in selecting the appropriate network interface when
transmitting packets.
provides some packet routing facilities.
The kernel maintains a routing information database, which
is used in selecting the appropriate network interface when
transmitting packets.
A user process (or possibly multiple co-operating processes)
maintains this database by sending messages over a special kind
of socket.
This supplants fixed size
A user process (or possibly multiple co-operating processes)
maintains this database by sending messages over a special kind
of socket.
This supplants fixed size
Each network interface in a system corresponds to a
path through which messages may be sent and received. A network
interface usually has a hardware device associated with it, though
certain interfaces such as the loopback interface,
Each network interface in a system corresponds to a
path through which messages may be sent and received. A network
interface usually has a hardware device associated with it, though
certain interfaces such as the loopback interface,
-#define IFNAMSIZ 16
- char ifr_name[IFNAMSIZE]; /* if name, e.g. "en0" */
- union {
- struct sockaddr ifru_addr;
- struct sockaddr ifru_dstaddr;
- struct sockaddr ifru_broadaddr;
- short ifru_flags;
- int ifru_metric;
- caddr_t ifru_data;
- } 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_metric ifr_ifru.ifru_metric /* metric */
-#define ifr_data ifr_ifru.ifru_data /* for use by interface */
+#define IFNAMSIZ 16
+ char ifr_name[IFNAMSIZE]; /* if name, e.g. "en0" */
+ union {
+ struct sockaddr ifru_addr;
+ struct sockaddr ifru_dstaddr;
+ struct sockaddr ifru_broadaddr;
+ short ifru_flags;
+ int ifru_metric;
+ caddr_t ifru_data;
+ } 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_metric ifr_ifru.ifru_metric /* metric */
+#define ifr_data ifr_ifru.ifru_data /* for use by interface */
Set interface address for protocol family. Following the address
assignment, the ``initialization'' routine for
the interface is called.
Set interface address for protocol family. Following the address
assignment, the ``initialization'' routine for
the interface is called.
requests to obtain addresses and requests both to set and
retreive other data are still fully supported
and use the
requests to obtain addresses and requests both to set and
retreive other data are still fully supported
and use the
Set interface flags field. If the interface is marked down,
any processes currently routing packets through the interface
are notified;
some interfaces may be reset so that incoming packets are no longer received.
When marked up again, the interface is reinitialized.
Set interface flags field. If the interface is marked down,
any processes currently routing packets through the interface
are notified;
some interfaces may be reset so that incoming packets are no longer received.
When marked up again, the interface is reinitialized.
An interface may have more than one address associated with it
in some protocols. This request provides a means to
add additional addresses (or modify characteristics of the
An interface may have more than one address associated with it
in some protocols. This request provides a means to
add additional addresses (or modify characteristics of the
is specified). Rather than making separate calls to
set destination or broadcast addresses, or network masks
(now an integral feature of multiple protocols)
is specified). Rather than making separate calls to
set destination or broadcast addresses, or network masks
(now an integral feature of multiple protocols)
-a separate structure is used to specify all three facets simultaneously:
-.nf
-
-.ta \w'struct 'u +\w'struct 'u +\w'sockaddr 'u +\w'ifra_broaddadr 'u
-struct ifaliasreq {
- char ifra_name[IFNAMSIZ]; /* if name, e.g. "en0" */
- struct sockaddr ifra_addr;
- struct sockaddr ifra_broadaddr;
- struct sockaddr ifra_mask;
-};
-.fi
+a separate structure is used to specify all three facets simultaneously
+(see below).
One would use a slightly tailored version of this struct specific
to each family (replacing each sockaddr by one
of the family-specific type).
Where the sockaddr itself is larger than the
default size, one needs to modify the
One would use a slightly tailored version of this struct specific
to each family (replacing each sockaddr by one
of the family-specific type).
Where the sockaddr itself is larger than the
default size, one needs to modify the
structure to allow for the possibility of protocols allowing
multiple masks or destination addresses, and also adopts the
convention that specification of the default address means
to delete the first address for the interface belonging to
the address family in which the original socket was opened.
structure to allow for the possibility of protocols allowing
multiple masks or destination addresses, and also adopts the
convention that specification of the default address means
to delete the first address for the interface belonging to
the address family in which the original socket was opened.
+.El
+.Bd -literal
+/*
+* Structure used in SIOCAIFCONF request.
+*/
+struct ifaliasreq {
+ char ifra_name[IFNAMSIZ]; /* if name, e.g. "en0" */
+ struct sockaddr ifra_addr;
+ struct sockaddr ifra_broadaddr;
+ struct sockaddr ifra_mask;
+};
+.Ed
+.Pp
+.Bd -literal
- * 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 associated 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 structures returned */
+* 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 associated 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 structures returned */