.\" t
.\" Don't change the first line, it tells man that tbl is needed.
.\" This man page copyright 1998 by Andi Kleen. Subject to the GPL.
.\" This manpage copyright 1998 by Andi Kleen. Subject to the GPL.
.\" Based on the original comments from Alexey Kuznetsov
.\" $Id: netlink.7,v 1.1.1.1 2000/12/27 12:24:46 BitBIRD Exp $
.\" İ Copyright (c) 2000 LetBrightBitBIRD  www.linuxforum.net
.TH NETLINK 7 "27 Apr 1999" "Linux Man Page" "Linux Programmer's Manual"
.SH NAME 
netlink, PF_NETLINK \- ںû֮ͨѶ
.SH SYNOPSIS 
.nf
.\" XXX
.B #include <asm/types.h>
.br
.B #include <sys/socket.h>
.br
.B #include <linux/netlink.h> 
.br
.PP
.BI "netlink_socket = socket(PF_NETLINK, " socket_type ", " netlink_family ); 
.SH DESCRIPTION 
Netlink ںģûַռеĽ֮䴫Ϣġ
û̵Ļڱ׼׽ֵĽӿںںģһڲ
APIйڲĽӿڵûаڴֲҳСͬ
һʱͨ netlink ַ豸ĽӿҲûаڴˣֻṩ
¼ԡ

Netlink һݰķ
.B SOCK_RAW

.B SOCK_DGRAM

.IR socket_type
ЧֵȻ netlink Эݰ datagram ԭ׽֣raw sockets
֡

.I netlink_family
ѡģ netlink ͨѶпָ netlink У 
.TP
.B NETLINK_ROUTE
·ɸϢ޸ IPv4 ·ɱ(μ
.BR rtnetlink (7))
.TP
.B NETLINK_FIREWALL
 IPv4 ǽ뷢͵ݰ
.TP
.B NETLINK_ARPD
άûַռ arp 
.TP
.B NETLINK_ROUTE6
պͷ IPv6 ·ɱϢ
.TP
.B NETLINK_IP6_FW
δͨ IPv6 ǽݰ(δʵ)
.TP
.BR NETLINK_TAPBASE ... NETLINK_TAPBASE+15

.B ethertap
豸ʵEthertap Ǵûռ̫
ġαͨ豸
.TP
.B NETLINK_SKIP
Enskip ıѡ
.TP
.B NETLINK_USERSOCK
ΪûռЭñѡ
.PP
Netlink Ϣɾһ
.B nlmsghdr
ݱͷЧݵֽɡڷֳɶݰ Netlink Ϣ
ݱͷе
.B NLM_F_MULTI
־λãһıͷб־
.BR NLMSG_DONE ⡣
ֽӦֻñ׼
.B NLMSG_*
ʣ
.BR netlink (3). 

Netlink ǿɿЭ顣ֻǾܵؽϢ䵽Ŀĵأڴ
ʱᶪʧϢΪ֤Ϣɿ䣬ñ־
.B NLM_F_ACK
Ҫշȷϡݽȷһ
.B NLMSG_ERROR
ݰеijֶΪ 0ӦóԼյϢȷϢ
Ϣ͹Уںһֱ()ÿݰ
.B NLMSG_ERROR
ϢûҲӦѭһ

ÿһ netlink ඼һ32λ㲥飬
׽ֵ
.BR bind (2)
ʱ 
.B sockaddr_nl
е
.B nl_groups
ֶóҪĹ㲥λ롣ĬֵΪ 0ʾκι㲥

һ׽ֿԶһַ㲥㲥ϢֻҪڵ
.BR sendmsg (2) 

.BR connect (2) 
ʱλ
.B nl_groups
óҪϢĹ㲥ֵͿˡ
ֻоЧ uid Ϊ 0 û

.B CAP_NET_ADMIN
Ȩ޵ûſܷͻ netlink ַ㲥Ϣ
κһԶַ㲥ϢӦ跢ؽ̱ʶ pid ͹㲥ַ

.RS
.nf
.ta 4 13 25
struct nlmsghdr
{
__u32 nlmsg_len; /* ͷڵϢ*/
__u16 nlmsg_type; /* Ϣ */
__u16 nlmsg_flags; /* ӱ־*/
__u32 nlmsg_seq; /* к*/
__u32 nlmsg_pid; /* ͽ̺ PID */
};


struct nlmsgerr
{
int error; /* ʾij errno Ϊ 0 Ҫȷ acks*/ 
struct nlmsghdr msg; /* ɳϢͷ*/ 
};
.ta
.fi
.RE

ÿ
.B nlmsghdr
Чݡ
.B nlmsg_type
ԳΪ׼Ϣͣ
.B NLMSG_NOOP
ԺԵϢ
.B NLMSG_ERROR
Ϣйаһ 
.I nlmsgerr 
ṹ
.B NLMSG_DONE
һݰϢϢ
.\" 2.1.130 ʹ
.\" .B NLMSG_OVERRUN
.\" ݶ. 

һ netlink ָͨϢͣйֲҳ
.IR NETLINK_ROUTE .
е 
.BR rtnetlink (7)

.TS 
tab(:); 
l s 
l l.
nlmsg_flags ı׼־λ
NLM_F_REQUEST: ȫϢ
NLM_F_MULTI:T{
ϢǶݰϢ֮һͨ־
.B NLMSG_DONE

.\" XXX describe that
T}
NLM_F_ACK: ݳɹշȷϢ
NLM_F_ECHO: ҪӦϢ
.TE

.TS
tab(:);
l s 
l l.
Ϊ GET ĸӱ־λ
NLM_F_ROOT: ضǵ
NLM_F_MATCH: δʵ
NLM_F_ATOMIC: ضԭӿ(atomic snapshot) 
NLM_F_DUMP: δĵ
.TE

.TS
tab(:);
l s
l l.
½ NEW ĸӱ־λ
NLM_F_REPLACE: 滻еĶ
NLM_F_EXCL: Ѵڣ滻
NLM_F_CREATE: 󲻴
NLM_F_APPEND: Ӷ
.TE

ע NLM_F_ATOMIC Ҫû CAP_NET_ADMIN 򳬼ûȨ

.SH ַʽ

.B sockaddr_nl
ûռںĿռһ netlink ͻݽṹ
һ sockaddr_nl ǵַ㲥һ netlink ַ
(nl_groups Ϊ 0).

.RS
.nf
struct sockaddr_nl
{
sa_family_t nl_family; /* AF_NETLINK */
unsigned short nl_pad; /*  */
pid_t nl_pid; /* ̱ʶpid */
__u32 nl_groups; /* ַ㲥*/
};
.fi
.RE

.B nl_pid 
ûռ netlink Ḻ̌ʶ pidںʱֵΪ 0
.B nl_groups 
һ neltlink ŵλ롣
.\" XXX describe what that is. 


.SH BUGS
ֲҳ


.SH  NOTES ע
ͨ
.B libnetlink
 netlink ͨͨͲں˽ӿҪúЩ


.SH VERSIONS 汾
netlink ׽ֽӿ Linux 2.2 

Linux 2.0 ָ֧Ļnetlinkӿڵԭʼ豸(Ϊ¼ԣ
Щ豸ĿǰԿʹáɽӿûڴ

.SH 
.BR cmsg (3),
.BR rtnetlink (7),
.BR netlink (3).
.PP
.BR ftp://ftp.inr.ac.ru/ip-routing/iproute2* 
й libnetlink 
.SH "[İά]"
LetBright E-mail:letbright@netease.com
.SH "[ݸ]" 2000/11/09
.br
.B й Linux ̳ man ֲҳƻ:www.cmpp.net/