.\" t
.\" Ҫ޸.֪manҪtbl֧.
.\" manҳȨ(C)1999 Andi Kleen .
.\" İȨ riser, Laser www.linuxforum.net 2000
.\" ޸ĵĸҳ汾ҪȨ,
.\" һֲذ header (ͷʶ),˽ϴ
.\" ĵ,޸ߺӵ header .
.\" $Id: ip.7,v 1.1.1.1 2000/12/27 12:24:43 BitBIRD Exp $
.TH IP 7 "1999511" "Linux ֲҳ" "Linux Աֲ"
.SH NAME ()
ip \- Linux IPv4 Эʵ
.SH SYNOPSIS()
.B #include <sys/socket.h>
.br
.B #include <net/netinet.h>
.sp
.IB tcp_socket " = socket(PF_INET, SOCK_STREAM, 0);"
.br
.IB raw_socket " = socket(PF_INET, SOCK_RAW, " protocol ");"
.br
.IB udp_socket " = socket(PF_INET, SOCK_DGRAM, " protocol ");"
.SH DESCRIPTION()
Linux ʵ RFC791  RFC1122 е Internet Э,汾4.
.B ip
ѭ RFC1112 ĵڶĶŵ㲥ʵ.ҲIP·.
.\" XXX:û֤2.1ȷʵ1812ݵ?
.PP
ԱĽӿ BSD ׽(socket)ݣ
Ҫù׽ֵĸϢ,μ
.BR socket (7)
.PP
һIP׽ͨ
.BR "socket(PF_INET, socket_type, protocol)"
ʽ
.BR socket (2)
ʵֵģ
Ч׽ͣsocket_typeУ
.B SOCK_STREAM
һ
.BR tcp (7)
׽֣
.B SOCK_DGRAM
һ
.BR udp (7)
׽֣
.B SOCK_RAW
һ
.BR raw (7)
׽ֱӷ IP Э飮
.I protocol
ָҪջ߷ͳȥİ IP ͷʶ(header)е IP Э飮
TCP׽ֶ,ΨһЧ
.I protocol
ֵ
.B 0

.B IPPROTO_TCP
UDP׽ֶ,ΨһЧ
.I protocol
ֵ
.B 0

.B IPPROTO_UDP.

.B SOCK_RAW
ָһ RFC1700 жЧ IANA IP Эֵ.
.PP
.\" XXX ipǰڼлԶ,ҲȷǷӦĵ
һϣµðʱ,Ӧʹ
.BR bind (2)
һ׽ֵһؽӿڵַ
ı(ַ,˿)ֻܰһIP׽֣
 bind ʱ
.B INADDR_ANY
ʱ,׽ֽ󶨵
.I 
ؽӿڣδ󶨵׽ϵ
.BR listen (2)

.BR connect (2)
ʱ,׽ֻԶ󶨵һصַΪ
.BR INADDR_ANY
Ŀж˿ϣ


.B S0_REUSEADDR 
ʶһѰ󶨵 TCP ׽ֵַڹرպһʱڲã
ʹøñʶʱҪСģΪʹ TCP òɿ

.SH ADDRESS FORMAT(ַʽ)
һ IP ׽ֵַΪһ IP ӿڵַһ˿ںŵϣ
 IP Э鲻ṩ˿ں,߲ͨεЭ
.BR udp (7)

.BR tcp (7)
ʵ֣
raw׽֣
.B sin_port
ΪIPЭ飮

.PP
.RS
.nf
.ta 4n 19n 31n
struct sockaddr_in {
sa_family_t sin_family; /* ַ: AF_INET */
u_int16_t sin_port; /* ֽڴĶ˿ */
struct in_addr sin_addr; /* internetַ */
};

/* Internetַ. */
struct in_addr {
u_int32_t s_addr; /* ֽڴĵַ */
};
.ta
.fi
.RE
.PP
.I sin_family
Ϊ
.BR AF_INET .
DZģ Linux 2.2 Уȱʧ᷵
.B EINVAL
.I sin_port
ֽĶ˿ںţ˿ں1024µijΪ
.IR "˿"
ֻЩЧûʶΪ 0 
.B CAP_NET_BIND_SERVICE
йܵĽ̲ſ
.BR bind (2)
Щ׽֣עԭʼģrawIPv4ЭûĶ˿ڸ,ֻͨߵЭ
.BR tcp (7)

.BR udp (7)
ʵ֣
.PP
.I sin_addr
ָ IP ַ.

.B struct in_addr
е
.I addr
ְֽӿڵַ
.B in_addr
Ӧֻͨʹ
.BR inet_aton (3),
.BR inet_addr (3),
.BR inet_makeaddr (3)
⺯ֱֽͨμ
.BR gethostbyname (3)
ʣ
IPv4 ֳַɵ㲥㲥ͺͶ㲥ַ
㲥ַָһ̨ĵһӿڣ㲥ַָ
һϵ
㲥ַһ㴫Ѱַ.
ֻе׽ֱʶ
.B SO_BROADCAST 
ʱ
շݱ㲥ַ
ڵǰʵУӵ׽ֻʹõ㴫͵ַ
.\" ΪXTPһ© @)

עַͶ˿ǰֽ洢ģ
ζҪԷ˿ڵĺ
.BR htons (3) 
ڱ׼еĵַ/˿ڴǰֽеģ

мĵַ
.B INADDR_LOOPBACK
(127.0.0.1)
Ǵɻػ豸ı
.B INADDR_ANY
(0.0.0.0)
ʾκοɰ󶨵ĵַ
.B INADDR_BROADCAST
(255.255.255.255)
ʾκʷԭΪ
.B INADDR_ANY
ͬЧ.

.SH SOCKET OPTIONS(׽ѡ)

IP ֧һЩЭص׽ѡЩѡͨ
.BR setsockopt (2)
ãͨ
.BR getsockopt (2)
ȡ
IP ׽ѡΪ
.B SOL_IP
. һͱʶ,ֵΪ0ʱΪ,Ϊ.

.TP
.B IP_OPTIONS
û߻ȡɸ׽ַ͵ÿ IP ѡ
òһָѡѡȵĴ洢ָ룮
.BR setsockopt (2)
ϵͳһ׽ IP ѡ.
IPv4 ѡΪ 40 ֽڣ
 RFC791 ȡõѡ
һ
.B SOCK_STREAM
׽յijʼ IP ѡʱ
IP ѡԶΪԳʼѡͬʱת·ͷ
ӽԺ󽫲õİ޸ѡ
ȱʡǹرնðԴ·ѡģ
.B accept_source_route
sysctl Ȼѡʱtimestamp
ݱ׽ֶԣIP ѡֻɱûãô
.I IP_OPTIONS

.BR getsockopt (2)
ѵǰڷ͵ IP ѡŵṩĻУ

.TP
.B IP_PKTINFO
һ
.B pktinfo
ṹ(ýṹṩһЩðϢ)
.I IP_PKTINFO
Ϣ.
ѡֻݱ׽Ч
.IP
.RS
.ta 4n 19n 33n
.nf
struct in_pktinfo
{
unsigned int ipi_ifindex; /* ӿ */
struct in_addr ipi_spec_dst; /* ·Ŀĵַ */
struct in_addr ipi_addr; /* ͷʶĿĵַ */
};
.fi
.RE
.IP
.\" XXX ϸЩ
.B ipi_ifindex
ָǽհĽӿڵΨһ
.\" XXX ?
.B ipi_spec_dst
ָ·ɱ¼еĿĵַ
.B ipi_addr
ָǰͷеĿĵַ
 sendmsg (2)
.I IP_PKTINFO
ôⷢİͨ
.B ipi_ifindex
ָĽӿ
ͳȥͬʱ
.B ipi_spec_dst
ΪĿĵַ

.TP
.B IP_RECVTOS
ѡ
.I IP_TOS ,
Ϣðһ𴫵ݣ
һָֽͷеķ/ȼֶεͣ
ֽΪһͱʶ

.TP
.B IP_RECVTTL
˸ñʶʱ
һһֽڱʾĽհʱ䣨time to liveֶε
.I IP_RECVTTL
Ϣ
ѡ֧
.B SOCK_STREAM
׽֣

.TP
.B IP_RECVOPTS
һ
.I IP_OPTIONS
Ϣõ IP ѡû
·ͷʶѡѾΪã
ѡ֧
.I SOCK_STREAM
׽֣

.TP
.B IP_RETOPTS
ͬ
.I IP_RECVOPTS
ǷصǴʱδԭʼѡ·δ·ɼ¼Ŀ

.TP
.B IP_TOS
û߽Դڸ׽ֵÿIP Type-Of-Service
TOS ֶͣΣְȼ
TOS ǵֽڵֶΣһЩı׼ TOS ʶ
.B IPTOS_LOWDELAY
ΪʽͨСӳʱ䣬
.B IPTOS_THROUGHPUT
Ż
.B IPTOS_RELIABILITY
ɿŻ
.B IPTOS_MINCOST
Ӧñ""Щݣٴ޹ؽҪģ
ֻЩ TOS ֵеһĶЧģӦ
ȱʡʱ,Linuxȷ
.B IPTOS_LOWDELAY
ݱ,
ȷеҪõŶӹ.
.\" XXX ϸЩ
һЩȼIJοܻҪһЧûʶ 0 
.B CAP_NET_ADMIN
.
ȼҲЭ޹صķʽͨ(
.B SOL_SOCKET, SO_PRIORITY
)׽ѡ(ο
.BR socket (7)
).

.TP
.B IP_TTL
û߼Ӵ׽ַİĵǰʱֶ.

.TP
.B IP_HDRINCL
򿪵Ļ,
ôûûǰṩһ ip ͷ.
ֻ
.B SOCK_RAW
Ч.ο
.BR raw (7)
ԻøϢ.˸ñʶ֮,ֵ
.IR IP_OPTIONS
趨,
.I IP_TOS
.

.TP
.B IP_RECVERR
չĿɿĴϢ.
ݱϼ˸ñʶ,
ôвĴÿ׽һĴŶӵȴ.
û׽ֲյʱ,Ϳͨ
.B MSG_ERRQUEUE
ʶ
.BR recvmsg (2)
.

.B sock_extended_err
ṹͨһΪ
.I IP_RECVERR ,
Ϊ
.BR SOL_IPĸϢд.
ѡδӵ׽Ͽɿش.
еյݲְ.
.IP
IP ķʹ
.B sock_extended_err
ṹ
ICMP յĴ
.I ee_origin
Ϊ
.B SO_EE_ORIGIN_ICMP ,
ڱزĴΪ
.B SO_EE_ORIGIN_LOCAL .
.I ee_type

.I ee_code
Ϊ ICMP ͷʶͺʹֶ.
.I ee_info

.B EMSGSIZE
ʱҵ MTU.
.I ee_data
Ŀǰûʹ.
ʱ,׽IPѡ
.RI ( IP_OPTIONS ", " IP_TTL ", "
ȣ)ҵϢд.İЧغɻݷ.
.IP
.\" XXX:ЩĵǸ?һȷ.

.B SOCK_STREAM
׽ϣ
.I IP_RECVERR
ϸ΢岻ͬ.´γʱĴ,нĴû.
 TCP ʱ̵ܶ,ΪҪٵĴ.
ʹøѡҪС:Ϊ·תƺ
ȷؽлָ,ʹTCPòɿ,ƻЭĹ淶.
עTCPûд;
.B MSG_ERRQUEUE

.B SOCK_STREAM
׽ǷǷ.
д󶼻׽ֺ,ֻ
.B SO_ERROR .
.IP
ԭʼ(raw)׽ֶ,
.I IP_RECVERR
нյICMPӦó,ֻӵ׽ϱ.
.IP
û߼һͲʶ.
.I IP_RECVERR
ȱʡΪoff(ر).

.TP
.B IP_PMTU_DISCOVER
Ϊ׽ûPath MTU Discovery setting(·MTU).
ʱ,Linuxڸ׽ִж
RFC1191еPath MTU Discovery(·MTU).
don't αʶⷢݱ.
ϵͳȱʡֵģ
.B SOCK_STREAM
׽
.B ip_no_pmtu_disc
sysctl ƣе׽ֶεˣڷ
.B SOCK_STREAM
׽ֶ,
ûΰMTUĴСݷֿ鲢ڱҪ½мط.˸ñʶ
(
.B EMSGSIZE
),ں˻ܾ֪·MTUİ.

.TS
tab(:);
c l
l l.
Path MTU discovery(·MTU)ʶ:
IP_PMTUDISC_WANT:ÿ·.
IP_PMTUDISC_DONT:ӲPath MTU Discovery(·MTU).
IP_PMTUDISC_DO:Path MTU Discovery(·MTU).
.TE


 PMTU ·MTUʱ,
ں˻Զ¼ÿĿpath MTU(·MTU).ʹ
.BR connect (2)
ӵһָĶԶ˻ʱ,Էʹ
.B IP_MTU
׽ѡǰ֪ path MTU(·MTU)(磬ڷһ
.B EMSGSIZE
).ʱƶı.
ڴĿĶ˵ķӵ׽,һضĿĶ˵µ MTU 
Ҳʹô(ο
.BR IP_RECVERR )
ȡ.
µĴΪÿε MTU ĸŶӵȴ.

 MTU ʱ,ݱ׽ֵijʼܻᱻ.
ʹ UDP ӦóӦ֪ҿ
м̴Ͳ.

Ϊδӵ׽· MTU ֽ,
ǿһݱ(ͷߴ糬64Kֽ),
ͨ· MTU .
.\" XXX һª

Ϊ˻·MTUӵijʼ,ͨʹ
.BR connect (2)
һݱ׽ӵĿĵַ,ͨô
.B IP_MTUѡ
.BR getsockopt (2)
MTU.

.TP
.B IP_MTU
ǰ׽ֵĵǰ֪·MTU.ֻ׽ֱʱЧ.һ.ֻΪһ
.BR getsockopt (2)
Ч.
.\"
.TP
.B IP_ROUTER_ALERT
׽нҪתİIP·棨IP RouterAlert optionѡ.
ֻԭʼ׽֣raw socketЧ,ûռ RSVP
̨ػ֮.
ֽİܱںת,ûת.׽ְ󶨱,
ЩֻЭ.
Ҫһͱʶ.
.\"
.TP
.B IP_MULTICAST_TTL
û߶ȡ׽ֵⷢ㲥ʱֵ.
ڶ㲥ÿܵСTTLҪ.
ȱʡֵΪ1,ζŶ㲥ᳬ,
ûȷҪô.һ.
.\"
.TP
.B IP_MULTICAST_LOOP
ûȡһͲԾ͵Ķ㲥ǷӦñ͵׽.
.\"
.TP
.B IP_ADD_MEMBERSHIP
һ㲥.Ϊ
.B struct ip_mreqn
ṹ.
.PP
.RS
.nf
.ta 4n 19n 34n
struct ip_mreqn
{
struct in_addr imr_multiaddr; /* IP㴫ַ */
struct in_addr imr_address; /* ؽӿڵIPַ */
int imr_ifindex; /* ӿ */
};
.fi
.RE
.IP
.I imr_multiaddr
Ӧóϣ˳Ķ㲥ĵַ.
һЧĶ㲥ַ.
.I imr_address
ָϵͳ㲥ıؽӿڵַ;
.B INADDR_ANY
һ,ôϵͳѡһʵĽӿ.
.I imr_ifindex
ָҪ/
.I imr_multiaddr
Ľӿ,Ϊ0ʾκνӿ.
.IP
ڼԵԵ,ϵ
.B ip_mreq
ӿȻ֧.
.B ip_mreqn
ֻһطͬ,ûа
.I imr_ifindex
ֶ.ֻΪһ
.BR setsockopt (2)
ʱЧ.
.\"
.TP
.B IP_DROP_MEMBERSHIP
һ㲥.Ϊ
.B ip_mreqn

.B ip_mreq
ṹ,
.IR IP_ADD_MEMBERSHIP
.
.\"
.\TP
.B IP_MULTICAST_IF
Ϊ㲥׽ñ豸.Ϊ
.B ip_mreqn

.B ip_mreq
ṹ,
.IR IP_ADD_MEMBERSHIP
.
.IP
һЧ׽ѡʱ,
.B ENOPROTOOPT .
.SH SYSCTLS
IPЭ֧ sysctl ӿһЩȫѡ.sysctlͨȡд
.B /proc/sys/net/ipv4/*
ļʹ
.BR sysctl (2)
ӿȡ.
.\"
.TP
.B ip_default_ttl
ⷢȱʡʱֵ.ֵԶÿ׽ͨ
.I IP_TTL
ѡ޸.
.\"
.TP
.B ip_forward
һʶIPת.IPתҲ԰ӿ
.\"
.TP
.B ip_dynaddr
򿪽ӿڵַıʱ̬׽ֵַαװ¼д.
Ծб仯IPַIJŽӿں
.0ʾд,1书,2򼤻ģʽ.
.\"
.TP
.B ip_autoconfig
ĵ
.\"
.TP
.B ip_local_port_range
,ȱʡ׽ֵıض˿ڷΧ.
ʼڵһֹڵڶ.
עЩ˿ڲαװʹõĶ˿ͻ(ҲԴ).
ͬʱ,ѡܻᵼһЩǽ,ǻΪض˿ʹ.
һ>1024,>4096Ա֪Ķ˿ڷͻ
Ӷܵļٷǽ.
.\"
.TP
.B ip_no_pmtu_disc
,ȱʡ²TCP׽ִ·MTU.
·˷ǽ(
ICMP)˽ӿ
(,һMTUͬĶ˶Զ),·MTUֿܻʧ.
Ը޸·ϵ𻵵·,Ҳùعر·MTU,
Ϊᵼϵĸ߿.
.\"
.TP
.B ipfrag_high_thresh, ipfrag_low_thresh
ŶӵȴIPƬĿﵽ
.B ipfrag_high_thresh ,
бſΪ
.B ipfrag_low_thresh .
һʾֽ.
.TP
.B ip_always_defrag
[kernel 2.2.13е¹;ں˰汾,ùڱʱͨ
.B CONFIG_IP_ALWAYS_DEFRAG
ѡ]

òʶ(0)ʱ,
õƬ(IPһ,ڵһЩԴ˺ĿĶ֮
ָ̫Ƭ)ڴ֮ǰ(Ƭ),
ʹҪתҲˣ

ֻһ̨絥һӵķǽ͸ʱô;
·,
ԶҪ.
ƬڲͬͨʱƬͨſܻᱻ.
ƬҲҪѴڴ CPU ʱ䣮

αװ͸Զ.
.TP
.B neigh/*
ο
.BR arp (7)
.\" XXX confĵ/*/* sysctls
.\" XXX routeĵ/* sysctls
.\" XXX ǵĵ
.SH IOCTLS

.BR socket (7)
  ioctl Ӧip.
.PP
÷ǽӦõioctl
.B ipchains

.BR ipfw (7)
ĵ.
.PP
ͨ豸ioctl
.BR netdevice (7)
.
.\" XXX һйض㴫͵
.SH NOTES(ע)
ʹ
.B SO_BROADCAST
ѡҪС \-  Linux ûȨҪ.
СĵĹ㲥׵.µӦЭ,
ʹö㲥㲥.Dzʹù㲥.
.PP
ЩBSD׽ʵṩ
.I IP_RCVDSTADDR

.I IP_RECVIF
׽ѡĿĵַԼݱĽӿ.Linuxиͨõ
.I IP_PKTINFO
ͬ.
.PP
.SH ERRORS()
.\" XXXдĵ.ȷʵӦ޸ںԷظͳһĴϢ(ENOMEM
ENOBUFS,EPERMEACCES.)
.TP
.B ENOTCONN
ֻӵ׽,׽ȴû.
.TP
.B EINVAL
ЧIJ.
ڷͲ,͵һ
.I blackhole(ڶ)
·ɶ.
.TP
.B EMSGSIZE
ݱڸ·ϵ MTU,ֳܱƬ.
.TP
.B EACCES
ûбҪȨ޵ûͼִһҪijЩȨ޵IJ.
:
û
.B SO_BROADCAST
ʶõ·һ㲥ַ.
ͨһ
.I ֹ
·ɷͰ.
û
.B CAP_NET_ADMIN
ЧûʶΪ0޸ķǽ.
û
.B CAP_NET_BIND_SERVICE
ЧûʶΪ0°һ˿.

.TP
.B EADDRINUSE
ͼ󶨵һʹõĵַ.
.TP
.BR ENOMEM "  " ENOBUFS
û㹻ڴ.
.TP
.BR ENOPROTOOPT "  " EOPNOTSUPP
Ч׽ѡ.
.TP
.B EPERM
ûûȨøȼ,޸û߷źŵĽ̻.
.TP
.B EADDRNOTAVAIL
һڵĽӿڻԴ˵ַDZص.
.TP
.B EAGAIN
һ׽Ͻв.
.TP
.B ESOCKTNOSUPPORT
׽δûһδ֪͵׽.
.TP
.B EISCONN
һѾӵ׽ϵ
.BR connect (2) .
.TP
.B EALREADY
һ׽ϵӲѾڽ.
.TP
.B ECONNABORTED
һ
.BR accept (2)
ִӱر.
.TP
.B EPIPE
رջ߱Զ˹ر.
.TP
.B ENOENT
ûб׽ϵ
.B SIOCGSTAMP .
.TP
.B EHOSTUNREACH
ûЧ·ɱ¼ƥĿĵַ.ôԱԶ·
ICMPϢΪ·ɱԵʶ.
.TP
.B ENODEV
豸û߲ڷIP.
.TP
.B ENOPKG
ںϵͳû.
.TP
.B ENOBUFS, ENOMEM
û㹻Ŀڴ.
ⳣζڴ׽ֻƶ,
ΪϵͳڴԵ,Ҳ100%ȷ
.PP
صЭ;ο
.BR tcp (7),
.BR raw (7),
.BR udp (7)

.BR socket (7).
.SH VERSIONS(汾)
.IR IP_PKTINFO ,
.IR IP_MTU ,
.IR IP_PMTU_DISCOVER ,
.IR IP_PKTINFO ,
.IR IP_RECVERR

.IR IP_ROUTER_ALERT
Linux 2.2еѡ.
.PP
.B struct ip_mreqn
Ҳ³Linux 2.2е.Linux 2.0ֻ֧
.BR ip_mreq .
.PP
sysctlLinux 2.2.
.SH COMPATIBILITY()
ΪLinux 2.0,Ȼ֧ùʱ
.BI "socket(PF_INET, SOCK_RAW, "protocol ")"
﷨һ
.BR packet (7)
׽.Dz޳ô,Ӧñ
.BI "socket(PF_PACKET, SOCK_RAW, "protocol ")"
.Ҫ
µһӲϢ
.B sockaddr_ll
ַṹ滻˾ɵ
.B sockaddr_pkt
ַṹ.
.SH BUGS
಻Ĵ.
.PP
ûضIPӿѡARPioctl.
.SH AUTHORS()
manҳAndi Kleen.
.SH SEE ALSO()
.BR sendmsg (2),
.BR recvmsg (2),
.BR socket (7),
.BR netlink (7),
.BR tcp (7),
.BR udp (7),
.BR raw (7),
.BR ipfw (7).
.PP
RFC791:ԭʼIP淶.
.br
RFC1122:IPv4.
.br
RFC1812:IPv4·.
\" ˽: XXX Զ INADDR REUSEADDR

.SH "[İά]"
riser Email: boomer@ccienet.com
.SH "[ݸ]"
2000/11/06

.SH "[йLinux̳manֲҳƻ]"
.TP
.BI www.cmpp.net/