diff options
Diffstat (limited to 'man7/socket.7')
| -rw-r--r-- | man7/socket.7 | 317 |
1 files changed, 159 insertions, 158 deletions
diff --git a/man7/socket.7 b/man7/socket.7 index 4325492b4e..634f0f612a 100644 --- a/man7/socket.7 +++ b/man7/socket.7 @@ -203,11 +203,102 @@ with the socket level set to .B SOL_SOCKET for all sockets: .\" FIXME Place following list in alphabetical order? +.\" +.\" SO_ACCEPTCONN is in SUSv3, and its origin is explained in +.\" W R Stevens, UNPv1 +.TP +.B SO_ACCEPTCONN +Returns a value indicating whether or not this socket has been marked +to accept connections with +.BR listen (). +The value 0 indicates that this is not a listening socket, +the value 1 indicates that this is a listening socket. +Can only be read +with +.BR getsockopt (). +.TP +.B SO_BSDCOMPAT +Enable BSD bug-to-bug compatibility. +This is used by the UDP protocol module in Linux 2.0 and 2.2. +If enabled ICMP errors received for a UDP socket will not be passed +to the user program. +In later kernel versions, support for this option has been phased out: +Linux 2.4 silently ignores it, and Linux 2.6 generates a kernel warning +(printk()) if a program uses this option. +Linux 2.0 also enabled BSD bug-to-bug compatibility +options (random header changing, skipping of the broadcast flag) for raw +sockets with this option, but that was removed in Linux 2.2. +.TP +.B SO_BINDTODEVICE +Bind this socket to a particular device like \(lqeth0\(rq, +as specified in the passed interface name. If the +name is an empty string or the option length is zero, the socket device +binding is removed. The passed option is a variable-length null terminated +interface name string with the maximum size of +.BR IFNAMSIZ . +If a socket is bound to an interface, +only packets received from that particular interface are processed by the +socket. Note that this only works for some socket types, particularly +.B AF_INET +sockets. It is not supported for packet sockets (use normal +.BR bind (8) +there). +.TP +.B SO_BROADCAST +Set or get the broadcast flag. When enabled, datagram sockets +receive packets sent to a broadcast address and they are allowed to send +packets to a broadcast address. +This option has no effect on stream-oriented sockets. +.TP +.B SO_DEBUG +Enable socket debugging. Only allowed for processes with the +.B CAP_NET_ADMIN +capability or an effective user ID of 0. +.TP +.B SO_ERROR +Get and clear the pending socket error. Only valid as a +.BR getsockopt (). +Expects an integer. +.TP +.B SO_DONTROUTE +Don't send via a gateway, only send to directly connected hosts. +The same effect can be achieved by setting the +.B MSG_DONTROUTE +flag on a socket +.BR send (2) +operation. Expects an integer boolean flag. .TP .B SO_KEEPALIVE Enable sending of keep-alive messages on connection-oriented sockets. Expects an integer boolean flag. .TP +.B SO_LINGER +Sets or gets the +.B SO_LINGER +option. The argument is a +.I linger +structure. +.sp +.in +0.25i +.nf +struct linger { + int l_onoff; /* linger active */ + int l_linger; /* how many seconds to linger for */ +}; +.fi +.in -0.25i +.IP +When enabled, a +.BR close (2) +or +.BR shutdown (2) +will not return until all queued messages for the socket have been +successfully sent or the linger timeout has been reached. Otherwise, +the call returns immediately and the closing is done in the background. +When the socket is closed as part of +.BR exit (2), +it always lingers in the background. +.TP .B SO_OOBINLINE If this option is enabled, out-of-band data is directly placed into the receive data stream. @@ -217,6 +308,46 @@ flag is set during receiving. .\" don't document it because it can do too much harm. .\".B SO_NO_CHECK .TP +.B SO_PASSCRED +Enable or disable the receiving of the +.B SCM_CREDENTIALS +control message. For more information see +.BR unix (7). +.TP +.B SO_PEERCRED +Return the credentials of the foreign process connected to this socket. +This is only possible for connected +.B PF_UNIX +stream sockets and +.B PF_UNIX +stream and datagram socket pairs created using +.BR socketpair (2); +see +.BR unix (7). +The returned credentials are those that were in effect at the time +of the call to +.BR connect (2) +or +.BR socketpair (2). +Argument is a +.I ucred +structure. +Only valid as a +.BR getsockopt (). +.TP +.B SO_PRIORITY +Set the protocol-defined priority for all packets to be sent on +this socket. +Linux uses this value to order the networking queues: +packets with a higher priority may be processed first depending +on the selected device queueing discipline. +For +.BR ip (7), +this also sets the IP type-of-service (TOS) field for outgoing packets. +Setting a priority outside the range 0 to 6 requires the +.B CAP_NET_ADMIN +capability. +.TP .BR SO_RCVLOWAT " and " SO_SNDLOWAT Specify the minimum number of bytes in the buffer until the socket layer will pass the data to the protocol @@ -264,64 +395,29 @@ just as if the socket was specified to be nonblocking. If the timeout is set to zero (the default) then the operation will never timeout. .TP -.B SO_BSDCOMPAT -Enable BSD bug-to-bug compatibility. -This is used by the UDP protocol module in Linux 2.0 and 2.2. -If enabled ICMP errors received for a UDP socket will not be passed -to the user program. -In later kernel versions, support for this option has been phased out: -Linux 2.4 silently ignores it, and Linux 2.6 generates a kernel warning -(printk()) if a program uses this option. -Linux 2.0 also enabled BSD bug-to-bug compatibility -options (random header changing, skipping of the broadcast flag) for raw -sockets with this option, but that was removed in Linux 2.2. -.TP -.B SO_PASSCRED -Enable or disable the receiving of the -.B SCM_CREDENTIALS -control message. For more information see -.BR unix (7). -.TP -.B SO_PEERCRED -Return the credentials of the foreign process connected to this socket. -This is only possible for connected -.B PF_UNIX -stream sockets and -.B PF_UNIX -stream and datagram socket pairs created using -.BR socketpair (2); -see -.BR unix (7). -The returned credentials are those that were in effect at the time -of the call to -.BR connect (2) -or -.BR socketpair (2). -Argument is a -.I ucred -structure. -Only valid as a +.B SO_RCVBUF +Sets or gets the maximum socket receive buffer in bytes. +The kernel doubles this value (to allow space for bookkeeping overhead) +when it is set using +.\" Most (all?) other implementations do not do this -- MTK, Dec 05 +.BR setsockopt (), +and this doubled value is returned by .BR getsockopt (). +The default value is set by the +.B rmem_default +sysctl and the maximum allowed value is set by the +.B rmem_max +sysctl. +The minimum (doubled) value for this option is 256. .TP -.B SO_BINDTODEVICE -Bind this socket to a particular device like \(lqeth0\(rq, -as specified in the passed interface name. If the -name is an empty string or the option length is zero, the socket device -binding is removed. The passed option is a variable-length null terminated -interface name string with the maximum size of -.BR IFNAMSIZ . -If a socket is bound to an interface, -only packets received from that particular interface are processed by the -socket. Note that this only works for some socket types, particularly -.B AF_INET -sockets. It is not supported for packet sockets (use normal -.BR bind (8) -there). -.TP -.B SO_DEBUG -Enable socket debugging. Only allowed for processes with the -.B CAP_NET_ADMIN -capability or an effective user ID of 0. +.BR SO_RCVBUFFORCE " (since Linux 2.6.14") +Using this socket option, a privileged +.RB ( CAP_NET_ADMIN ) +process can perform the same task as +.BR SO_RCVBUF , +but the +.B rmem_max +limit can be overridden. .TP .B SO_REUSEADDR Indicates that the rules used in validating addresses supplied in a @@ -336,39 +432,6 @@ When the listening socket is bound to with a specific port then it is not possible to bind to this port for any local address. .TP -.B SO_TYPE -Gets the socket type as an integer (like -.BR SOCK_STREAM ). -Can only be read -with -.BR getsockopt (). -.\" SO_ACCEPTCONN is in SUSv3, and its origin is explained in -.\" W R Stevens, UNPv1 -.TP -.B SO_ACCEPTCONN -Returns a value indicating whether or not this socket has been marked -to accept connections with -.BR listen (). -The value 0 indicates that this is not a listening socket, -the value 1 indicates that this is a listening socket. -Can only be read -with -.BR getsockopt (). -.TP -.B SO_DONTROUTE -Don't send via a gateway, only send to directly connected hosts. -The same effect can be achieved by setting the -.B MSG_DONTROUTE -flag on a socket -.BR send (2) -operation. Expects an integer boolean flag. -.TP -.B SO_BROADCAST -Set or get the broadcast flag. When enabled, datagram sockets -receive packets sent to a broadcast address and they are allowed to send -packets to a broadcast address. -This option has no effect on stream-oriented sockets. -.TP .B SO_SNDBUF Sets or gets the maximum socket send buffer in bytes. The kernel doubles this value (to allow space for bookkeeping overhead) @@ -393,75 +456,6 @@ but the .B wmem_max limit can be overridden. .TP -.B SO_RCVBUF -Sets or gets the maximum socket receive buffer in bytes. -The kernel doubles this value (to allow space for bookkeeping overhead) -when it is set using -.\" Most (all?) other implementations do not do this -- MTK, Dec 05 -.BR setsockopt (), -and this doubled value is returned by -.BR getsockopt (). -The default value is set by the -.B rmem_default -sysctl and the maximum allowed value is set by the -.B rmem_max -sysctl. -The minimum (doubled) value for this option is 256. -.TP -.BR SO_RCVBUFFORCE " (since Linux 2.6.14") -Using this socket option, a privileged -.RB ( CAP_NET_ADMIN ) -process can perform the same task as -.BR SO_RCVBUF , -but the -.B rmem_max -limit can be overridden. -.TP -.B SO_LINGER -Sets or gets the -.B SO_LINGER -option. The argument is a -.I linger -structure. -.sp -.in +0.25i -.nf -struct linger { - int l_onoff; /* linger active */ - int l_linger; /* how many seconds to linger for */ -}; -.fi -.in -0.25i -.IP -When enabled, a -.BR close (2) -or -.BR shutdown (2) -will not return until all queued messages for the socket have been -successfully sent or the linger timeout has been reached. Otherwise, -the call returns immediately and the closing is done in the background. -When the socket is closed as part of -.BR exit (2), -it always lingers in the background. -.TP -.B SO_PRIORITY -Set the protocol-defined priority for all packets to be sent on -this socket. -Linux uses this value to order the networking queues: -packets with a higher priority may be processed first depending -on the selected device queueing discipline. -For -.BR ip (7), -this also sets the IP type-of-service (TOS) field for outgoing packets. -Setting a priority outside the range 0 to 6 requires the -.B CAP_NET_ADMIN -capability. -.TP -.B SO_ERROR -Get and clear the pending socket error. Only valid as a -.BR getsockopt (). -Expects an integer. -.TP .B SO_TIMESTAMP Enable or disable the receiving of the .B SO_TIMESTAMP @@ -476,6 +470,13 @@ reception time of the last packet passed to the user in this call. See .BR cmsg (3) for details on control messages. +.TP +.B SO_TYPE +Gets the socket type as an integer (like +.BR SOCK_STREAM ). +Can only be read +with +.BR getsockopt (). .SH SIGNALS When writing onto a connection-oriented socket that has been shut down (by the local or the remote end) |