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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-04-12 22:42:49 +0000 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-04-12 22:42:49 +0000 |
| commit | c13182efa3b3d77f2563034c8212c0ca798243ca (patch) | |
| tree | e7652b26018b7c22cd6a4e4b41404dfaab911303 /man7/netdevice.7 | |
| parent | 4174ff5658082832c2ed511720f18881b3a80a34 (diff) | |
| download | man-pages-c13182efa3b3d77f2563034c8212c0ca798243ca.tar.gz | |
Wrapped long lines, wrapped at sentence boundaries; stripped trailing
white space.
Diffstat (limited to 'man7/netdevice.7')
| -rw-r--r-- | man7/netdevice.7 | 105 |
1 files changed, 57 insertions, 48 deletions
diff --git a/man7/netdevice.7 b/man7/netdevice.7 index b3ab1d9dc0..2b6885174b 100644 --- a/man7/netdevice.7 +++ b/man7/netdevice.7 @@ -9,7 +9,7 @@ .\" .\" Modified, 2004-11-25, mtk, formatting and a few wording fixes .\" -.TH NETDEVICE 7 1999-05-02 "Linux Man Page" "Linux Programmer's Manual" +.TH NETDEVICE 7 1999-05-02 "Linux Man Page" "Linux Programmer's Manual" .SH NAME netdevice \- Low level access to Linux network devices .SH SYNOPSIS @@ -20,11 +20,11 @@ netdevice \- Low level access to Linux network devices This man page describes the sockets interface which is used to configure network devices. -Linux supports some standard ioctls to configure network devices. -They can be used on any socket's file descriptor regardless of the -family or type. -They pass an -.B ifreq +Linux supports some standard ioctls to configure network devices. +They can be used on any socket's file descriptor regardless of the +family or type. +They pass an +.B ifreq structure: .nf @@ -47,24 +47,26 @@ struct ifreq { }; }; -struct ifconf { +struct ifconf { int ifc_len; /* size of buffer */ - union { - char * ifc_buf; /* buffer address */ + union { + char * ifc_buf; /* buffer address */ struct ifreq * ifc_req; /* array of structures */ - }; -}; + }; +}; .fi Normally, the user specifies which device to affect by setting .B ifr_name -to the name of the interface. All other members of the structure may -share memory. +to the name of the interface. +All other members of the structure may +share memory. .SH IOCTLS If an ioctl is marked as privileged then using it requires an effective user ID of 0 or the .B CAP_NET_ADMIN -capability. If this is not the case +capability. +If this is not the case .B EPERM will be returned. .TP @@ -107,7 +109,7 @@ IFF_AUTOMEDIA:Auto media selection active. IFF_DYNAMIC:T{ The addresses are lost when the interface goes down. T} -.TE +.TE Setting the active flag word is a privileged operation, but any process may read it. .TP @@ -123,7 +125,8 @@ if you attempt to set it. .BR SIOCGIFMTU ", " SIOCSIFMTU Get or set the MTU (Maximum Transfer Unit) of a device using .BR ifr_mtu . -Setting the MTU is a privileged operation. Setting the MTU to +Setting the MTU is a privileged operation. +Setting the MTU to too small values may cause kernel crashes. .TP .BR SIOCGIFHWADDR ", " SIOCSIFHWADDR @@ -131,10 +134,10 @@ Get or set the hardware address of a device using .BR ifr_hwaddr . The hardware address is specified in a struct .IR sockaddr . -.I sa_family -contains the ARPHRD_* device type, +.I sa_family +contains the ARPHRD_* device type, .I sa_data -the L2 hardware address starting from byte 0. +the L2 hardware address starting from byte 0. Setting the hardware address is a privileged operation. .TP .B SIOCSIFHWBROADCAST @@ -151,10 +154,10 @@ Setting the parameters is a privileged operation. struct ifmap { unsigned long mem_start; unsigned long mem_end; - unsigned short base_addr; - unsigned char irq; - unsigned char dma; - unsigned char port; + unsigned short base_addr; + unsigned char irq; + unsigned char dma; + unsigned char port; }; .fi @@ -176,38 +179,42 @@ Get or set the transmit queue length of a device using Setting the transmit queue length is a privileged operation. .TP .B SIOCSIFNAME -Changes the name of the interface specified in +Changes the name of the interface specified in .BR ifr_name to .BR ifr_newname . -This is a privileged operation. It is only allowed when the interface +This is a privileged operation. +It is only allowed when the interface is not up. .TP .B SIOCGIFCONF -Return a list of interface (transport layer) addresses. This currently -means only addresses of the AF_INET (IPv4) family for compatibility. -The user passes a +Return a list of interface (transport layer) addresses. +This currently +means only addresses of the AF_INET (IPv4) family for compatibility. +The user passes a .B ifconf -structure as argument to the ioctl. It contains a pointer to an array of +structure as argument to the ioctl. +It contains a pointer to an array of .I ifreq -structures in +structures in .B ifc_req -and its length in bytes in +and its length in bytes in .BR ifc_len . The kernel fills the ifreqs with all current L3 interface addresses that -are running: -.I ifr_name -contains the interface name (eth0:1 etc.), +are running: +.I ifr_name +contains the interface name (eth0:1 etc.), .I ifr_addr the address. -The kernel returns with the actual length in +The kernel returns with the actual length in .IR ifc_len . -If +If .I ifc_len is equal to the original length the buffer probably has overflowed and you should retry with a bigger buffer to get all addresses. When no error occurs the ioctl returns 0; -otherwise \-1. Overflow is not an error. +otherwise \-1. +Overflow is not an error. .\" FIXME Slaving isn't supported in 2.2 .\" . .\" .TP @@ -218,30 +225,32 @@ otherwise \-1. Overflow is not an error. .\" .PP .\" FIXME add amateur radio stuff. .PP -Most protocols support their own ioctls to configure protocol specific -interface options. See the protocol man pages for a description. -For configuring IP addresses see +Most protocols support their own ioctls to configure protocol specific +interface options. +See the protocol man pages for a description. +For configuring IP addresses see .BR ip (7). .PP -In addition some devices support private ioctls. +In addition some devices support private ioctls. These are not described here. .SH NOTES Strictly speaking, -.B SIOCGIFCONF -is IP specific and belongs in +.B SIOCGIFCONF +is IP specific and belongs in .BR ip (7). .LP The names of interfaces with no addresses or that don't have the -.B IFF_RUNNING +.B IFF_RUNNING flag set can be found via .IR /proc/net/dev . .LP -Local IPv6 IP addresses can be found via /proc/net or via +Local IPv6 IP addresses can be found via /proc/net or via .BR rtnetlink (7). .SH BUGS -glibc 2.1 is missing the -.I ifr_newname -macro in net/if.h. Add the following to your program as a workaround: +glibc 2.1 is missing the +.I ifr_newname +macro in net/if.h. +Add the following to your program as a workaround: .sp .RS .nf |