diff options
| -rw-r--r-- | share/man/man4/route.4 | 122 |
1 files changed, 77 insertions, 45 deletions
diff --git a/share/man/man4/route.4 b/share/man/man4/route.4 index 4e820ae020f..542e48e7f6a 100644 --- a/share/man/man4/route.4 +++ b/share/man/man4/route.4 @@ -1,4 +1,4 @@ -.\" $OpenBSD: route.4,v 1.19 2004/06/19 20:00:19 cedric Exp $ +.\" $OpenBSD: route.4,v 1.20 2004/08/10 15:07:11 jaredy Exp $ .\" $NetBSD: route.4,v 1.3 1994/11/30 16:22:31 jtc Exp $ .\" .\" Copyright (c) 1990, 1991, 1993 @@ -41,7 +41,7 @@ .Fd #include <net/if.h> .Fd #include <net/route.h> .Ft int -.Fn socket PF_ROUTE SOCK_RAW "int family" +.Fn socket PF_ROUTE SOCK_RAW family .Sh DESCRIPTION .Ox provides some packet routing facilities. @@ -58,13 +58,13 @@ used in earlier releases. Routing table changes may only be carried out by the super user. .Pp The operating system may spontaneously emit routing messages in response -to external events, such as receipt of a re-direct, or failure to +to external events, such as receipt of a redirect, or failure to locate a suitable route for a request. The message types are described in greater detail below. .Pp Routing database entries come in two flavors: for a specific host, or for all hosts on a generic subnetwork (as specified -by a bit mask and value under the mask. +by a bit mask and value under the mask). The effect of wildcard or default route may be achieved by using a mask of all zeros, and there may be hierarchical routes. .Pp @@ -87,43 +87,59 @@ the most specific route matching the destination. (If there are two different mask and value-under-the-mask pairs that match, the more specific is the one with more bits in the mask. A route to a host is regarded as being supplied with a mask of -as many ones as there are bits in the destination). +as many ones as there are bits in the destination.) If no entry is found, the destination is declared to be unreachable, and a routing\-miss message is generated if there are any listeners on the routing control socket described below. .Pp A wildcard routing entry is specified with a zero -destination address value, and a mask of all zeroes. +destination address value and a mask of all zeroes. Wildcard routes will be used when the system fails to find other routes matching the destination. The combination of wildcard routes and routing redirects can provide an economical mechanism for routing traffic. +Routes created by redirects from wildcard routes and other routes +will be marked +.Em cloned , +until their +.Dq parent +from which they were created has disappeared. .Pp +Route labels can be attached to routes and may contain arbitrary +information about the route. +Labels are sent over the routing socket (see below) as +.Vt sockaddr_rtlabel +structures. +.Ss The Routing Socket One opens the channel for passing routing control messages -by using the socket call shown in +by using the +.Xr socket 2 +call shown in the .Sx SYNOPSIS -above: +above. .Pp The .Fa family parameter may be -.Dv AF_UNSPEC +.Dv AF_UNSPEC , which will provide routing information for all address families, or can be restricted to a specific address family by specifying which one is desired. There can be more than one routing socket open per system. .Pp Messages are formed by a header followed by a small -number of sockaddrs (now variable length particularly -in the -.Tn ISO -case), interpreted by position, and delimited -by the new length entry in the sockaddr. +number of +.Vt sockaddr +structures (which are variable length), +interpreted by position, and delimited +by the length entry in the +.Vt sockaddr . An example of a message with four addresses might be an -.Tn ISO -redirect: -Destination, Netmask, Gateway, and Author of the redirect. +IPv4 route addition: the destination, netmask, gateway, and label, +since both netmasks and labels are sent over the routing socket as +.Vt sockaddr +structures. The interpretation of which addresses are present is given by a bit mask within the header, and the sequence is least significant to most significant bit within the vector. @@ -137,22 +153,22 @@ However, message replies may be lost when kernel buffers are exhausted. .Pp The kernel may reject certain messages, and will indicate this by filling in the -.Ar rtm_errno +.Va rtm_errno field. The routing code returns -.Dv EEXIST +.Er EEXIST if requested to duplicate an existing entry, -.Dv ESRCH +.Er ESRCH if requested to delete a non-existent entry, or -.Dv ENOBUFS +.Er ENOBUFS if insufficient resources were available to install a new route. In the current implementation, all routing processes run locally, and the values for -.Ar rtm_errno +.Va rtm_errno are available through the normal .Va errno mechanism, even if the routing reply message is lost. @@ -178,7 +194,7 @@ be reclaimed until all references to it are released. User processes can obtain information about the routing entry to a specific destination by using a .Dv RTM_GET -message, or via the +message or via the .Dv PF_ROUTE .Xr sysctl 3 . .Pp @@ -217,8 +233,7 @@ struct rt_msghdr { u_long rtm_inits; /* which metrics we are initializing */ struct rt_metrics rtm_rmx; /* metrics themselves */ }; -.Ed -.Bd -literal + struct if_msghdr { u_short ifm_msglen; /* to skip over non-understood messages */ u_char ifm_version; /* future binary compatibility */ @@ -228,8 +243,7 @@ struct if_msghdr { u_short ifm_index; /* index for associated ifp */ struct if_data ifm_data;/* statistics and other data about if */ }; -.Ed -.Bd -literal + struct ifa_msghdr { u_short ifam_msglen; /* to skip over non-understood messages */ u_char ifam_version; /* future binary compatibility */ @@ -239,8 +253,7 @@ struct ifa_msghdr { u_short ifam_index; /* index for associated ifp */ int ifam_metric; /* value of ifa_metric */ }; -.Ed -.Bd -literal + struct if_announcemsghdr { u_short ifan_msglen; /* to skip over non-understood messages */ u_char ifan_version; /* future binary compatibility */ @@ -253,22 +266,22 @@ struct if_announcemsghdr { .Pp The .Dv RTM_IFINFO -message uses a -.Ar if_msghdr +message uses an +.Vt if_msghdr header, the .Dv RTM_NEWADDR and .Dv RTM_DELADDR -messages use a -.Ar ifa_msghdr +messages use an +.Vt ifa_msghdr header, the .Dv RTM_IFANNOUNCE -message uses a -.Ar if_announcemsghdr +message uses an +.Vt if_announcemsghdr header, and all other messages use the -.Ar rt_msghdr +.Vt rt_msghdr header. .Pp The metrics structure is: @@ -286,8 +299,12 @@ struct rt_metrics { u_long rmx_pksent; /* packets sent using this route */ }; .Ed -Only rmx_mtu, rmx_expire, rmx_pksent, and rmx_locks are used by the kernel -routing table. +.Pp +Only +.Va rmx_mtu , rmx_expire , rmx_pksent , +and +.Va rmx_locks +are used by the kernel routing table. All other values will be ignored when inserting them into the kernel and are set to zero in routing messages sent by the kernel. They are left for compatibility reasons with other systems. @@ -307,15 +324,17 @@ Flags include the values: #define RTF_LLINFO 0x400 /* generated by ARP or ESIS */ #define RTF_STATIC 0x800 /* manually added */ #define RTF_BLACKHOLE 0x1000 /* just discard pkts (during updates) */ -#define RTF_PROTO3 0x2000 /* protocol specific routing flag */ #define RTF_PROTO2 0x4000 /* protocol specific routing flag */ #define RTF_PROTO1 0x8000 /* protocol specific routing flag */ #define RTF_CLONED 0x10000 /* this is a cloned route */ -#define RTF_SOURCE 0x20000 /* this route has a source selector */ #define RTF_MPATH 0x40000 /* multipath route or operation */ .Ed .Pp -Specifiers for metric values in rmx_locks and rtm_inits are: +Specifiers for metric values in +.Va rmx_locks +and +.Va rtm_inits +are: .Bd -literal #define RTV_MTU 0x1 /* init or lock _mtu */ #define RTV_HOPCOUNT 0x2 /* init or lock _hopcount */ @@ -326,7 +345,12 @@ Specifiers for metric values in rmx_locks and rtm_inits are: #define RTV_RTT 0x40 /* init or lock _rtt */ #define RTV_RTTVAR 0x80 /* init or lock _rttvar */ .Ed -Only RTV_MTU and RTV_EXPIRE should be used all other flags are ignored. +.Pp +Only +.Dv RTV_MTU +and +.Dv RTV_EXPIRE +should be used; all other flags are ignored. .Pp Specifiers for which addresses are present in the messages are: .Bd -literal @@ -338,9 +362,17 @@ Specifiers for which addresses are present in the messages are: #define RTA_IFA 0x20 /* interface addr sockaddr present */ #define RTA_AUTHOR 0x40 /* sockaddr for author of redirect */ #define RTA_BRD 0x80 /* for NEWADDR, bcast or p-p dest addr */ -#define RTA_SRC 0x100 /* source sockaddr present */ -#define RTA_SRCMASK 0x200 /* source netmask present */ +#define RTA_LABEL 0x400 /* route label present */ .Ed .Sh SEE ALSO +.Xr netstat 1 , .Xr socket 2 , -.Xr sysctl 3 +.Xr sysctl 3 , +.Xr mygate 5 , +.Xr route 8 , +.Xr routed 8 +.Sh HISTORY +A +.Dv PF_ROUTE +protocol family first appeared in +.Bx 4.3 Reno . |