2008-08-08 16:41:48 +00:00
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.\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>.
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.\" Permission is granted to distribute possibly modified copies
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.\" of this page provided the header is included verbatim,
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.\" and in case of nontrivial modification author and date
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.\" of the modification is added to the header.
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.\" $Id: rtnetlink.3,v 1.2 1999/05/18 10:35:10 freitag Exp $
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2010-01-16 16:27:35 +00:00
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.TH RTNETLINK 3 2010-01-11 "GNU" "Linux Programmer's Manual"
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2008-08-08 16:41:48 +00:00
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.SH NAME
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rtnetlink \- macros to manipulate rtnetlink messages
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.SH SYNOPSIS
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.B #include <asm/types.h>
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.br
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.B #include <linux/netlink.h>
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.br
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.B #include <linux/rtnetlink.h>
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.br
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.B #include <sys/socket.h>
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2008-08-08 16:47:53 +00:00
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.BI "rtnetlink_socket = socket(AF_NETLINK, int " socket_type \
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2008-08-08 16:41:48 +00:00
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", NETLINK_ROUTE);"
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.sp
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.BI "int RTA_OK(struct rtattr *" rta ", int " rtabuflen );
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.sp
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.BI "void *RTA_DATA(struct rtattr *" rta );
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.sp
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.BI "unsigned int RTA_PAYLOAD(struct rtattr *" rta );
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.sp
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.BI "struct rtattr *RTA_NEXT(struct rtattr *" rta \
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", unsigned int " rtabuflen );
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.sp
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.BI "unsigned int RTA_LENGTH(unsigned int " length );
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.sp
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.BI "unsigned int RTA_SPACE(unsigned int "length );
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.SH DESCRIPTION
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All
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.BR rtnetlink (7)
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messages consist of a
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.BR netlink (7)
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message header and appended attributes.
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The attributes should be only
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manipulated using the macros provided here.
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.PP
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.BI RTA_OK( rta ", " attrlen )
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returns true if
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.I rta
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points to a valid routing attribute;
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.I attrlen
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is the running length of the attribute buffer.
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When not true then you must assume there are no more attributes in the
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message, even if
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.I attrlen
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intro.1, time.1, adjtimex.2, capget.2, eventfd.2, fcntl.2, getrlimit.2, getsockopt.2, gettimeofday.2, intro.2, ioctl_list.2, ioperm.2, mlock.2, pivot_root.2, poll.2, prctl.2, ptrace.2, sched_setscheduler.2, select_tut.2, semget.2, sigaltstack.2, signalfd.2, sysctl.2, timer_settime.2, timerfd_create.2, wait.2, CPU_SET.3, argz_add.3, assert_perror.3, atexit.3, backtrace.3, bcmp.3, clearenv.3, ctime.3, dl_iterate_phdr.3, dlopen.3, ecvt.3, errno.3, error.3, ether_aton.3, exit.3, fenv.3, ferror.3, finite.3, flockfile.3, fnmatch.3, fpathconf.3, fpclassify.3, ftime.3, ftok.3, ftw.3, fwide.3, getaddrinfo.3, gethostbyname.3, getlogin.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getrpcent.3, getservent.3, glob.3, hsearch.3, inet.3, isalpha.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, longjmp.3, lsearch.3, malloc.3, matherr.3, mblen.3, mbsinit.3, mbtowc.3, on_exit.3, printf.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_equal.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setschedparam.3, pthread_setschedprio.3, ptsname.3, putenv.3, putgrent.3, raise.3, rcmd.3, regex.3, rexec.3, rpc.3, rpmatch.3, rtnetlink.3, scandir.3, sem_init.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, signbit.3, stdio_ext.3, strtod.3, strtol.3, strtoul.3, system.3, termios.3, timeradd.3, tzset.3, ualarm.3, wctomb.3, xdr.3, st.4, tty_ioctl.4, core.5, elf.5, proc.5, bootparam.7, capabilities.7, icmp.7, ip.7, ipv6.7, math_error.7, mdoc.samples.7, mq_overview.7, pthreads.7, raw.7, regex.7, socket.7, tcp.7, tzselect.8: Global fix: s/non-zero/nonzero/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:40:55 +00:00
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is nonzero.
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2008-08-08 16:41:48 +00:00
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.PP
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.BI RTA_DATA( rta )
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returns a pointer to the start of this attribute's data.
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.PP
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.BI RTA_PAYLOAD( rta )
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returns the length of this attribute's data.
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.PP
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.BI RTA_NEXT( rta ", " attrlen )
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gets the next attribute after
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.IR rta .
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Calling this macro will update
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.IR attrlen .
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You should use
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.B RTA_OK
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to check the validity of the returned pointer.
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.PP
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.BI RTA_LENGTH( len )
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returns the length which is required for
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.I len
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bytes of data plus the header.
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.PP
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.BI RTA_SPACE( len )
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returns the amount of space which will be needed in a message with
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.I len
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bytes of data.
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.SH CONFORMING TO
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accept.2, execve.2, futimesat.2, getresuid.2, getrlimit.2, madvise.2, mq_getsetattr.2, msgctl.2, nice.2, open.2, poll.2, setresuid.2, shmctl.2, sigaction.2, times.2, utimensat.2, __setfpucw.3, atoi.3, endian.3, err.3, euidaccess.3, fenv.3, fopencookie.3, fpurge.3, getgrouplist.3, getutmp.3, j0.3, lgamma.3, netlink.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_cleanup_push_defer_np.3, pthread_getattr_np.3, pthread_kill_other_threads_np.3, pthread_setaffinity_np.3, pthread_tryjoin_np.3, pthread_yield.3, random_r.3, readdir.3, rtnetlink.3, scanf.3, setenv.3, significand.3, sigsetops.3, strerror.3, strstr.3, sysv_signal.3, termios.3, timegm.3, unlocked_stdio.3, y0.3, locale.5, bootparam.7, feature_test_macros.7, ip.7, locale.7, pthreads.7, rtld-audit.7, nscd.8: Global fix: s/non-standard/nonstandard/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:37:52 +00:00
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These macros are nonstandard Linux extensions.
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2008-08-08 16:41:48 +00:00
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.SH BUGS
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This manual page is incomplete.
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.SH EXAMPLE
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.\" FIXME ? would be better to use libnetlink in the EXAMPLE code here
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Creating a rtnetlink message to set the MTU of a device:
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.nf
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2010-01-16 16:27:35 +00:00
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#include <linux/rtnetlink.h>
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...
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2008-08-08 16:41:48 +00:00
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struct {
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struct nlmsghdr nh;
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struct ifinfomsg if;
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char attrbuf[512];
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} req;
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struct rtattr *rta;
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unsigned int mtu = 1000;
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2008-08-08 16:47:53 +00:00
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int rtnetlink_sk = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
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2008-08-08 16:41:48 +00:00
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memset(&req, 0, sizeof(req));
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req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
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req.nh.nlmsg_flags = NLM_F_REQUEST;
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req.nh.nlmsg_type = RTM_NEWLINK;
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2008-08-08 16:41:48 +00:00
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req.if.ifi_family = AF_UNSPEC;
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req.if.ifi_index = INTERFACE_INDEX;
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2010-09-22 13:56:26 +00:00
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req.if.ifi_change = 0xffffffff; /* ??? */
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2008-08-08 16:41:48 +00:00
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rta = (struct rtattr *)(((char *) &req) +
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2010-09-22 13:56:26 +00:00
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NLMSG_ALIGN(req.nh.nlmsg_len));
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2008-08-08 16:41:48 +00:00
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rta\->rta_type = IFLA_MTU;
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rta\->rta_len = sizeof(unsigned int);
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2010-01-16 16:27:35 +00:00
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req.n.nlmsg_len = NLMSG_ALIGN(req.nh.nlmsg_len) +
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RTA_LENGTH(sizeof(mtu));
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memcpy(RTA_DATA(rta), &mtu, sizeof(mtu));
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2010-01-16 16:27:35 +00:00
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send(rtnetlink_sk, &req, req.nh.nlmsg_len);
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2008-08-08 16:41:48 +00:00
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.fi
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.SH "SEE ALSO"
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.BR netlink (3),
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.BR netlink (7),
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.BR rtnetlink (7)
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