.\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>.
+.\"
+.\" %%%LICENSE_START(VERBATIM_ONE_PARA)
.\" Permission is granted to distribute possibly modified copies
.\" of this page provided the header is included verbatim,
.\" and in case of nontrivial modification author and date
.\" of the modification is added to the header.
+.\" %%%LICENSE_END
+.\"
.\" $Id: rtnetlink.3,v 1.2 1999/05/18 10:35:10 freitag Exp $
-.TH RTNETLINK 3 1999-05-14 "Linux Man Page" "Linux Programmer's Manual"
+.\"
+.TH RTNETLINK 3 2021-03-22 "Linux man-pages (unreleased)" "Linux Programmer's Manual"
.SH NAME
-rtnetlink \- Macros to manipuate rtnetlink messages
+rtnetlink \- macros to manipulate rtnetlink messages
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
.SH SYNOPSIS
+.nf
.B #include <asm/types.h>
-.br
.B #include <linux/netlink.h>
-.br
.B #include <linux/rtnetlink.h>
-.br
.B #include <sys/socket.h>
-
-.BI "rtnetlink_socket = socket(PF_NETLINK, int " socket_type ", NETLINK_ROUTE);"
-.br
-.B int RTA_OK(struct rtattr *rta, int rtabuflen);
-.br
-.B void *RTA_DATA(struct rtattr *rta);
-.br
-.B unsigned int RTA_PAYLOAD(struct rtattr *rta);
-.br
-.B struct rtattr *RTA_NEXT(struct rtattr *rta, unsigned int rtabuflen);
-.br
-.B unsigned int RTA_LENGTH(unsigned int length);
-.br
-.B unsigned int RTA_SPACE(unsigned int length);
-.br
+.PP
+.BI "rtnetlink_socket = socket(AF_NETLINK, int " socket_type \
+", NETLINK_ROUTE);"
+.PP
+.BI "int RTA_OK(struct rtattr *" rta ", int " rtabuflen );
+.PP
+.BI "void *RTA_DATA(struct rtattr *" rta );
+.BI "unsigned int RTA_PAYLOAD(struct rtattr *" rta );
+.PP
+.BI "struct rtattr *RTA_NEXT(struct rtattr *" rta \
+", unsigned int " rtabuflen );
+.PP
+.BI "unsigned int RTA_LENGTH(unsigned int " length );
+.BI "unsigned int RTA_SPACE(unsigned int "length );
+.fi
.SH DESCRIPTION
-All
+All
.BR rtnetlink (7)
-messages consist of a
+messages consist of a
.BR netlink (7)
-message header and appended attributes. The attributes should be only
-manipulated using the macros provided here.
-
+message header and appended attributes.
+The attributes should be manipulated only using the macros provided here.
.PP
.BI RTA_OK( rta ", " attrlen )
returns true if
.I rta
points to a valid routing attribute;
.I attrlen
-is the running length of the attribute buffer.
+is the running length of the attribute buffer.
When not true then you must assume there are no more attributes in the
message, even if
.I attrlen
-is non-zero.
-.br
+is nonzero.
+.PP
.BI RTA_DATA( rta )
returns a pointer to the start of this attribute's data.
-.br
+.PP
.BI RTA_PAYLOAD( rta )
returns the length of this attribute's data.
-.br
+.PP
.BI RTA_NEXT( rta ", " attrlen )
gets the next attribute after
.IR rta .
.IR attrlen .
You should use
.B RTA_OK
-to check for the validity of the returned pointer.
-.br
+to check the validity of the returned pointer.
+.PP
.BI RTA_LENGTH( len )
returns the length which is required for
.I len
bytes of data plus the header.
-.br
+.PP
.BI RTA_SPACE( len )
-returns the amount of space which will be needed in the message with
+returns the amount of space which will be needed in a message with
.I len
bytes of data.
+.SH STANDARDS
+These macros are nonstandard Linux extensions.
+.SH BUGS
+This manual page is incomplete.
+.SH EXAMPLES
+.\" FIXME . ? would be better to use libnetlink in the EXAMPLE code here
+Creating a rtnetlink message to set the MTU of a device:
+.PP
+.in +4n
+.EX
+#include <linux/rtnetlink.h>
-.SH EXAMPLE
-.\" FIXME would be better to use libnetlink n the EXAMPLE code here
+\&...
-Creating a rtnetlink message to set a MTU of a device.
-.nf
- struct {
- struct nlmsghdr nh;
- struct ifinfomsg if;
- char attrbuf[512];
- } req;
- struct rtattr *rta;
- unsigned int mtu = 1000;
- int rtnetlink_sk = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
+struct {
+ struct nlmsghdr nh;
+ struct ifinfomsg if;
+ char attrbuf[512];
+} req;
- memset(&req, 0, sizeof(req));
- req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
- req.nh.nlmsg_flags = NLM_F_REQUEST;
- req.nh.nlmsg_type = RTML_NEWLINK;
- req.if.ifi_family = AF_UNSPEC;
- req.if.ifi_index = INTERFACE_INDEX;
- req.if.ifi_change = 0xffffffff; /* ???*/
- rta = (struct rtattr *)(((char *) &req) +
- NLMSG_ALIGN(n->nlmsg_len));
- rta->rta_type = IFLA_MTU;
- rta->rta_len = sizeof(unsigned int);
- req.n.nlmsg_len = NLMSG_ALIGN(req.n.nlmsg_len) +
- RTA_LENGTH(sizeof(mtu));
- memcpy(RTA_DATA(rta), &mtu, sizeof (mtu));
- send(rtnetlink_sk, &req, req.n.nlmsg_len);
-.fi
+struct rtattr *rta;
+unsigned int mtu = 1000;
-.SH BUGS
-This manual page is lacking and incomplete.
+int rtnetlink_sk = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
-.SH "SEE ALSO"
+memset(&req, 0, sizeof(req));
+req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.if));
+req.nh.nlmsg_flags = NLM_F_REQUEST;
+req.nh.nlmsg_type = RTM_NEWLINK;
+req.if.ifi_family = AF_UNSPEC;
+req.if.ifi_index = INTERFACE_INDEX;
+req.if.ifi_change = 0xffffffff; /* ??? */
+rta = (struct rtattr *)(((char *) &req) +
+ NLMSG_ALIGN(req.nh.nlmsg_len));
+rta\->rta_type = IFLA_MTU;
+rta\->rta_len = RTA_LENGTH(sizeof(mtu));
+req.nh.nlmsg_len = NLMSG_ALIGN(req.nh.nlmsg_len) +
+ RTA_LENGTH(sizeof(mtu));
+memcpy(RTA_DATA(rta), &mtu, sizeof(mtu));
+send(rtnetlink_sk, &req, req.nh.nlmsg_len, 0);
+.EE
+.in
+.SH SEE ALSO
.BR netlink (3),
.BR netlink (7),
.BR rtnetlink (7)
projects / thirdparty / man-pages.git / blobdiff