freebsd-dev/sys/net/route.h

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
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* Copyright (c) 1980, 1986, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
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* @(#)route.h 8.4 (Berkeley) 1/9/95
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* $FreeBSD$
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*/
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#ifndef _NET_ROUTE_H_
#define _NET_ROUTE_H_
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#include <net/vnet.h>
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/*
* Kernel resident routing tables.
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*
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* The routing tables are initialized when interface addresses
* are set by making entries for all directly connected interfaces.
*/
/*
* Struct route consiste of a destination address,
* a route entry pointer, link-layer prepend data pointer along
* with its length.
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*/
struct route {
struct nhop_object *ro_nh;
struct llentry *ro_lle;
/*
* ro_prepend and ro_plen are only used for bpf to pass in a
* preformed header. They are not cacheable.
*/
Implement interface link header precomputation API. Add if_requestencap() interface method which is capable of calculating various link headers for given interface. Right now there is support for INET/INET6/ARP llheader calculation (IFENCAP_LL type request). Other types are planned to support more complex calculation (L2 multipath lagg nexthops, tunnel encap nexthops, etc..). Reshape 'struct route' to be able to pass additional data (with is length) to prepend to mbuf. These two changes permits routing code to pass pre-calculated nexthop data (like L2 header for route w/gateway) down to the stack eliminating the need for other lookups. It also brings us closer to more complex scenarios like transparently handling MPLS nexthops and tunnel interfaces. Last, but not least, it removes layering violation introduced by flowtable code (ro_lle) and simplifies handling of existing if_output consumers. ARP/ND changes: Make arp/ndp stack pre-calculate link header upon installing/updating lle record. Interface link address change are handled by re-calculating headers for all lles based on if_lladdr event. After these changes, arpresolve()/nd6_resolve() returns full pre-calculated header for supported interfaces thus simplifying if_output(). Move these lookups to separate ether_resolve_addr() function which ether returs error or fully-prepared link header. Add <arp|nd6_>resolve_addr() compat versions to return link addresses instead of pre-calculated data. BPF changes: Raw bpf writes occupied _two_ cases: AF_UNSPEC and pseudo_AF_HDRCMPLT. Despite the naming, both of there have ther header "complete". The only difference is that interface source mac has to be filled by OS for AF_UNSPEC (controlled via BIOCGHDRCMPLT). This logic has to stay inside BPF and not pollute if_output() routines. Convert BPF to pass prepend data via new 'struct route' mechanism. Note that it does not change non-optimized if_output(): ro_prepend handling is purely optional. Side note: hackish pseudo_AF_HDRCMPLT is supported for ethernet and FDDI. It is not needed for ethernet anymore. The only remaining FDDI user is dev/pdq mostly untouched since 2007. FDDI support was eliminated from OpenBSD in 2013 (sys/net/if_fddisubr.c rev 1.65). Flowtable changes: Flowtable violates layering by saving (and not correctly managing) rtes/lles. Instead of passing lle pointer, pass pointer to pre-calculated header data from that lle. Differential Revision: https://reviews.freebsd.org/D4102
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char *ro_prepend;
uint16_t ro_plen;
uint16_t ro_flags;
uint16_t ro_mtu; /* saved ro_rt mtu */
uint16_t spare;
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struct sockaddr ro_dst;
};
Implement interface link header precomputation API. Add if_requestencap() interface method which is capable of calculating various link headers for given interface. Right now there is support for INET/INET6/ARP llheader calculation (IFENCAP_LL type request). Other types are planned to support more complex calculation (L2 multipath lagg nexthops, tunnel encap nexthops, etc..). Reshape 'struct route' to be able to pass additional data (with is length) to prepend to mbuf. These two changes permits routing code to pass pre-calculated nexthop data (like L2 header for route w/gateway) down to the stack eliminating the need for other lookups. It also brings us closer to more complex scenarios like transparently handling MPLS nexthops and tunnel interfaces. Last, but not least, it removes layering violation introduced by flowtable code (ro_lle) and simplifies handling of existing if_output consumers. ARP/ND changes: Make arp/ndp stack pre-calculate link header upon installing/updating lle record. Interface link address change are handled by re-calculating headers for all lles based on if_lladdr event. After these changes, arpresolve()/nd6_resolve() returns full pre-calculated header for supported interfaces thus simplifying if_output(). Move these lookups to separate ether_resolve_addr() function which ether returs error or fully-prepared link header. Add <arp|nd6_>resolve_addr() compat versions to return link addresses instead of pre-calculated data. BPF changes: Raw bpf writes occupied _two_ cases: AF_UNSPEC and pseudo_AF_HDRCMPLT. Despite the naming, both of there have ther header "complete". The only difference is that interface source mac has to be filled by OS for AF_UNSPEC (controlled via BIOCGHDRCMPLT). This logic has to stay inside BPF and not pollute if_output() routines. Convert BPF to pass prepend data via new 'struct route' mechanism. Note that it does not change non-optimized if_output(): ro_prepend handling is purely optional. Side note: hackish pseudo_AF_HDRCMPLT is supported for ethernet and FDDI. It is not needed for ethernet anymore. The only remaining FDDI user is dev/pdq mostly untouched since 2007. FDDI support was eliminated from OpenBSD in 2013 (sys/net/if_fddisubr.c rev 1.65). Flowtable changes: Flowtable violates layering by saving (and not correctly managing) rtes/lles. Instead of passing lle pointer, pass pointer to pre-calculated header data from that lle. Differential Revision: https://reviews.freebsd.org/D4102
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#define RT_L2_ME_BIT 2 /* dst L2 addr is our address */
#define RT_MAY_LOOP_BIT 3 /* dst may require loop copy */
#define RT_HAS_HEADER_BIT 4 /* mbuf already have its header prepended */
#define RT_L2_ME (1 << RT_L2_ME_BIT) /* 0x0004 */
#define RT_MAY_LOOP (1 << RT_MAY_LOOP_BIT) /* 0x0008 */
#define RT_HAS_HEADER (1 << RT_HAS_HEADER_BIT) /* 0x0010 */
#define RT_REJECT 0x0020 /* Destination is reject */
#define RT_BLACKHOLE 0x0040 /* Destination is blackhole */
#define RT_HAS_GW 0x0080 /* Destination has GW */
#define RT_LLE_CACHE 0x0100 /* Cache link layer */
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struct rt_metrics {
u_long rmx_locks; /* Kernel must leave these values alone */
u_long rmx_mtu; /* MTU for this path */
u_long rmx_hopcount; /* max hops expected */
u_long rmx_expire; /* lifetime for route, e.g. redirect */
u_long rmx_recvpipe; /* inbound delay-bandwidth product */
u_long rmx_sendpipe; /* outbound delay-bandwidth product */
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u_long rmx_ssthresh; /* outbound gateway buffer limit */
u_long rmx_rtt; /* estimated round trip time */
u_long rmx_rttvar; /* estimated rtt variance */
u_long rmx_pksent; /* packets sent using this route */
u_long rmx_weight; /* route weight */
Introduce nexthop objects and new routing KPI. This is the foundational change for the routing subsytem rearchitecture. More details and goals are available in https://reviews.freebsd.org/D24141 . This patch introduces concept of nexthop objects and new nexthop-based routing KPI. Nexthops are objects, containing all necessary information for performing the packet output decision. Output interface, mtu, flags, gw address goes there. For most of the cases, these objects will serve the same role as the struct rtentry is currently serving. Typically there will be low tens of such objects for the router even with multiple BGP full-views, as these objects will be shared between routing entries. This allows to store more information in the nexthop. New KPI: struct nhop_object *fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, uint32_t flowid); struct nhop_object *fib6_lookup(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, uint32_t flowid); These 2 function are intended to replace all all flavours of <in_|in6_>rtalloc[1]<_ign><_fib>, mpath functions and the previous fib[46]-generation functions. Upon successful lookup, they return nexthop object which is guaranteed to exist within current NET_EPOCH. If longer lifetime is desired, one can specify NHR_REF as a flag and get a referenced version of the nexthop. Reference semantic closely resembles rtentry one, allowing sed-style conversion. Additionally, another 2 functions are introduced to support uRPF functionality inside variety of our firewalls. Their primary goal is to hide the multipath implementation details inside the routing subsystem, greatly simplifying firewalls implementation: int fib4_lookup_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); int fib6_lookup_urpf(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); All functions have a separate scopeid argument, paving way to eliminating IPv6 scope embedding and allowing to support IPv4 link-locals in the future. Structure changes: * rtentry gets new 'rt_nhop' pointer, slightly growing the overall size. * rib_head gets new 'rnh_preadd' callback pointer, slightly growing overall sz. Old KPI: During the transition state old and new KPI will coexists. As there are another 4-5 decent-sized conversion patches, it will probably take a couple of weeks. To support both KPIs, fields not required by the new KPI (most of rtentry) has to be kept, resulting in the temporary size increase. Once conversion is finished, rtentry will notably shrink. More details: * architectural overview: https://reviews.freebsd.org/D24141 * list of the next changes: https://reviews.freebsd.org/D24232 Reviewed by: ae,glebius(initial version) Differential Revision: https://reviews.freebsd.org/D24232
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u_long rmx_nhidx; /* route nexhop index */
u_long rmx_filler[2]; /* will be used for T/TCP later */
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};
/*
* rmx_rtt and rmx_rttvar are stored as microseconds;
*/
#define RTM_RTTUNIT 1000000 /* units for rtt, rttvar, as units per sec */
/* lle state is exported in rmx_state rt_metrics field */
#define rmx_state rmx_weight
/* default route weight */
#define RT_DEFAULT_WEIGHT 1
#define RT_MAX_WEIGHT 16777215 /* 3 bytes */
/*
* Keep a generation count of routing table, incremented on route addition,
* so we can invalidate caches. This is accessed without a lock, as precision
* is not required.
*/
typedef volatile u_int rt_gen_t; /* tree generation (for adds) */
#define RT_GEN(fibnum, af) rt_tables_get_gen(fibnum, af)
#define RT_DEFAULT_FIB 0 /* Explicitly mark fib=0 restricted cases */
#define RT_ALL_FIBS -1 /* Announce event for every fib */
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#ifdef _KERNEL
VNET_DECLARE(uint32_t, _rt_numfibs); /* number of existing route tables */
#define V_rt_numfibs VNET(_rt_numfibs)
/* temporary compat arg */
#define rt_numfibs V_rt_numfibs
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VNET_DECLARE(u_int, rt_add_addr_allfibs); /* Announce interfaces to all fibs */
#define V_rt_add_addr_allfibs VNET(rt_add_addr_allfibs)
/* Calculate flowid for locally-originated packets */
#define V_fib_hash_outbound VNET(fib_hash_outbound)
VNET_DECLARE(u_int, fib_hash_outbound);
/* Outbound flowid generation rules */
#ifdef RSS
#define fib4_calc_packet_hash xps_proto_software_hash_v4
#define fib6_calc_packet_hash xps_proto_software_hash_v6
#define CALC_FLOWID_OUTBOUND_SENDTO true
#ifdef ROUTE_MPATH
#define CALC_FLOWID_OUTBOUND V_fib_hash_outbound
#else
#define CALC_FLOWID_OUTBOUND false
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#endif
#else /* !RSS */
#define fib4_calc_packet_hash fib4_calc_software_hash
#define fib6_calc_packet_hash fib6_calc_software_hash
#ifdef ROUTE_MPATH
#define CALC_FLOWID_OUTBOUND_SENDTO V_fib_hash_outbound
#define CALC_FLOWID_OUTBOUND V_fib_hash_outbound
#else
#define CALC_FLOWID_OUTBOUND_SENDTO false
#define CALC_FLOWID_OUTBOUND false
#endif
#endif /* RSS */
#endif /* _KERNEL */
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/*
* We distinguish between routes to hosts and routes to networks,
* preferring the former if available. For each route we infer
* the interface to use from the gateway address supplied when
* the route was entered. Routes that forward packets through
* gateways are marked so that the output routines know to address the
* gateway rather than the ultimate destination.
*/
#define RTF_UP 0x1 /* route usable */
#define RTF_GATEWAY 0x2 /* destination is a gateway */
#define RTF_HOST 0x4 /* host entry (net otherwise) */
#define RTF_REJECT 0x8 /* host or net unreachable */
#define RTF_DYNAMIC 0x10 /* created dynamically (by redirect) */
#define RTF_MODIFIED 0x20 /* modified dynamically (by redirect) */
#define RTF_DONE 0x40 /* message confirmed */
/* 0x80 unused, was RTF_DELCLONE */
/* 0x100 unused, was RTF_CLONING */
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#define RTF_XRESOLVE 0x200 /* external daemon resolves name */
#define RTF_LLINFO 0x400 /* DEPRECATED - exists ONLY for backward
compatibility */
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#define RTF_LLDATA 0x400 /* used by apps to add/del L2 entries */
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#define RTF_STATIC 0x800 /* manually added */
#define RTF_BLACKHOLE 0x1000 /* just discard pkts (during updates) */
#define RTF_PROTO2 0x4000 /* protocol specific routing flag */
#define RTF_PROTO1 0x8000 /* protocol specific routing flag */
/* 0x10000 unused, was RTF_PRCLONING */
/* 0x20000 unused, was RTF_WASCLONED */
#define RTF_PROTO3 0x40000 /* protocol specific routing flag */
#define RTF_FIXEDMTU 0x80000 /* MTU was explicitly specified */
#define RTF_PINNED 0x100000 /* route is immutable */
#define RTF_LOCAL 0x200000 /* route represents a local address */
#define RTF_BROADCAST 0x400000 /* route represents a bcast address */
#define RTF_MULTICAST 0x800000 /* route represents a mcast address */
/* 0x8000000 and up unassigned */
#define RTF_STICKY 0x10000000 /* always route dst->src */
/* 0x40000000 unused, was RTF_RNH_LOCKED */
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#define RTF_GWFLAG_COMPAT 0x80000000 /* a compatibility bit for interacting
with existing routing apps */
/* Mask of RTF flags that are allowed to be modified by RTM_CHANGE. */
#define RTF_FMASK \
(RTF_PROTO1 | RTF_PROTO2 | RTF_PROTO3 | RTF_BLACKHOLE | \
RTF_REJECT | RTF_STATIC | RTF_STICKY)
/*
* fib_ nexthop API flags.
*/
/* Consumer-visible nexthop info flags */
Introduce scalable route multipath. This change is based on the nexthop objects landed in D24232. The change introduces the concept of nexthop groups. Each group contains the collection of nexthops with their relative weights and a dataplane-optimized structure to enable efficient nexthop selection. Simular to the nexthops, nexthop groups are immutable. Dataplane part gets compiled during group creation and is basically an array of nexthop pointers, compiled w.r.t their weights. With this change, `rt_nhop` field of `struct rtentry` contains either nexthop or nexthop group. They are distinguished by the presense of NHF_MULTIPATH flag. All dataplane lookup functions returns pointer to the nexthop object, leaving nexhop groups details inside routing subsystem. User-visible changes: The change is intended to be backward-compatible: all non-mpath operations should work as before with ROUTE_MPATH and net.route.multipath=1. All routes now comes with weight, default weight is 1, maximum is 2^24-1. Current maximum multipath group width is statically set to 64. This will become sysctl-tunable in the followup changes. Using functionality: * Recompile kernel with ROUTE_MPATH * set net.route.multipath to 1 route add -6 2001:db8::/32 2001:db8::2 -weight 10 route add -6 2001:db8::/32 2001:db8::3 -weight 20 netstat -6On Nexthop groups data Internet6: GrpIdx NhIdx Weight Slots Gateway Netif Refcnt 1 ------- ------- ------- --------------------------------------- --------- 1 13 10 1 2001:db8::2 vlan2 14 20 2 2001:db8::3 vlan2 Next steps: * Land outbound hashing for locally-originated routes ( D26523 ). * Fix net/bird multipath (net/frr seems to work fine) * Add ROUTE_MPATH to GENERIC * Set net.route.multipath=1 by default Tested by: olivier Reviewed by: glebius Relnotes: yes Differential Revision: https://reviews.freebsd.org/D26449
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#define NHF_MULTIPATH 0x0008 /* Nexhop is a nexthop group */
#define NHF_REJECT 0x0010 /* RTF_REJECT */
#define NHF_BLACKHOLE 0x0020 /* RTF_BLACKHOLE */
#define NHF_REDIRECT 0x0040 /* RTF_DYNAMIC|RTF_MODIFIED */
#define NHF_DEFAULT 0x0080 /* Default route */
#define NHF_BROADCAST 0x0100 /* RTF_BROADCAST */
#define NHF_GATEWAY 0x0200 /* RTF_GATEWAY */
#define NHF_HOST 0x0400 /* RTF_HOST */
/* Nexthop request flags */
Introduce nexthop objects and new routing KPI. This is the foundational change for the routing subsytem rearchitecture. More details and goals are available in https://reviews.freebsd.org/D24141 . This patch introduces concept of nexthop objects and new nexthop-based routing KPI. Nexthops are objects, containing all necessary information for performing the packet output decision. Output interface, mtu, flags, gw address goes there. For most of the cases, these objects will serve the same role as the struct rtentry is currently serving. Typically there will be low tens of such objects for the router even with multiple BGP full-views, as these objects will be shared between routing entries. This allows to store more information in the nexthop. New KPI: struct nhop_object *fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, uint32_t flowid); struct nhop_object *fib6_lookup(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, uint32_t flowid); These 2 function are intended to replace all all flavours of <in_|in6_>rtalloc[1]<_ign><_fib>, mpath functions and the previous fib[46]-generation functions. Upon successful lookup, they return nexthop object which is guaranteed to exist within current NET_EPOCH. If longer lifetime is desired, one can specify NHR_REF as a flag and get a referenced version of the nexthop. Reference semantic closely resembles rtentry one, allowing sed-style conversion. Additionally, another 2 functions are introduced to support uRPF functionality inside variety of our firewalls. Their primary goal is to hide the multipath implementation details inside the routing subsystem, greatly simplifying firewalls implementation: int fib4_lookup_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); int fib6_lookup_urpf(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); All functions have a separate scopeid argument, paving way to eliminating IPv6 scope embedding and allowing to support IPv4 link-locals in the future. Structure changes: * rtentry gets new 'rt_nhop' pointer, slightly growing the overall size. * rib_head gets new 'rnh_preadd' callback pointer, slightly growing overall sz. Old KPI: During the transition state old and new KPI will coexists. As there are another 4-5 decent-sized conversion patches, it will probably take a couple of weeks. To support both KPIs, fields not required by the new KPI (most of rtentry) has to be kept, resulting in the temporary size increase. Once conversion is finished, rtentry will notably shrink. More details: * architectural overview: https://reviews.freebsd.org/D24141 * list of the next changes: https://reviews.freebsd.org/D24232 Reviewed by: ae,glebius(initial version) Differential Revision: https://reviews.freebsd.org/D24232
2020-04-12 14:30:00 +00:00
#define NHR_NONE 0x00 /* empty flags field */
#define NHR_REF 0x01 /* reference nexhop */
#define NHR_NODEFAULT 0x02 /* uRPF: do not consider default route */
Introduce nexthop objects and new routing KPI. This is the foundational change for the routing subsytem rearchitecture. More details and goals are available in https://reviews.freebsd.org/D24141 . This patch introduces concept of nexthop objects and new nexthop-based routing KPI. Nexthops are objects, containing all necessary information for performing the packet output decision. Output interface, mtu, flags, gw address goes there. For most of the cases, these objects will serve the same role as the struct rtentry is currently serving. Typically there will be low tens of such objects for the router even with multiple BGP full-views, as these objects will be shared between routing entries. This allows to store more information in the nexthop. New KPI: struct nhop_object *fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, uint32_t flowid); struct nhop_object *fib6_lookup(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, uint32_t flowid); These 2 function are intended to replace all all flavours of <in_|in6_>rtalloc[1]<_ign><_fib>, mpath functions and the previous fib[46]-generation functions. Upon successful lookup, they return nexthop object which is guaranteed to exist within current NET_EPOCH. If longer lifetime is desired, one can specify NHR_REF as a flag and get a referenced version of the nexthop. Reference semantic closely resembles rtentry one, allowing sed-style conversion. Additionally, another 2 functions are introduced to support uRPF functionality inside variety of our firewalls. Their primary goal is to hide the multipath implementation details inside the routing subsystem, greatly simplifying firewalls implementation: int fib4_lookup_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); int fib6_lookup_urpf(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); All functions have a separate scopeid argument, paving way to eliminating IPv6 scope embedding and allowing to support IPv4 link-locals in the future. Structure changes: * rtentry gets new 'rt_nhop' pointer, slightly growing the overall size. * rib_head gets new 'rnh_preadd' callback pointer, slightly growing overall sz. Old KPI: During the transition state old and new KPI will coexists. As there are another 4-5 decent-sized conversion patches, it will probably take a couple of weeks. To support both KPIs, fields not required by the new KPI (most of rtentry) has to be kept, resulting in the temporary size increase. Once conversion is finished, rtentry will notably shrink. More details: * architectural overview: https://reviews.freebsd.org/D24141 * list of the next changes: https://reviews.freebsd.org/D24232 Reviewed by: ae,glebius(initial version) Differential Revision: https://reviews.freebsd.org/D24232
2020-04-12 14:30:00 +00:00
/* Control plane route request flags */
#define NHR_COPY 0x100 /* Copy rte data */
#define NHR_UNLOCKED 0x200 /* Do not lock table */
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/*
* Routing statistics.
*/
struct rtstat {
uint64_t rts_badredirect; /* bogus redirect calls */
uint64_t rts_dynamic; /* routes created by redirects */
uint64_t rts_newgateway; /* routes modified by redirects */
uint64_t rts_unreach; /* lookups which failed */
uint64_t rts_wildcard; /* lookups satisfied by a wildcard */
Introduce nexthop objects and new routing KPI. This is the foundational change for the routing subsytem rearchitecture. More details and goals are available in https://reviews.freebsd.org/D24141 . This patch introduces concept of nexthop objects and new nexthop-based routing KPI. Nexthops are objects, containing all necessary information for performing the packet output decision. Output interface, mtu, flags, gw address goes there. For most of the cases, these objects will serve the same role as the struct rtentry is currently serving. Typically there will be low tens of such objects for the router even with multiple BGP full-views, as these objects will be shared between routing entries. This allows to store more information in the nexthop. New KPI: struct nhop_object *fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, uint32_t flowid); struct nhop_object *fib6_lookup(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, uint32_t flowid); These 2 function are intended to replace all all flavours of <in_|in6_>rtalloc[1]<_ign><_fib>, mpath functions and the previous fib[46]-generation functions. Upon successful lookup, they return nexthop object which is guaranteed to exist within current NET_EPOCH. If longer lifetime is desired, one can specify NHR_REF as a flag and get a referenced version of the nexthop. Reference semantic closely resembles rtentry one, allowing sed-style conversion. Additionally, another 2 functions are introduced to support uRPF functionality inside variety of our firewalls. Their primary goal is to hide the multipath implementation details inside the routing subsystem, greatly simplifying firewalls implementation: int fib4_lookup_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); int fib6_lookup_urpf(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); All functions have a separate scopeid argument, paving way to eliminating IPv6 scope embedding and allowing to support IPv4 link-locals in the future. Structure changes: * rtentry gets new 'rt_nhop' pointer, slightly growing the overall size. * rib_head gets new 'rnh_preadd' callback pointer, slightly growing overall sz. Old KPI: During the transition state old and new KPI will coexists. As there are another 4-5 decent-sized conversion patches, it will probably take a couple of weeks. To support both KPIs, fields not required by the new KPI (most of rtentry) has to be kept, resulting in the temporary size increase. Once conversion is finished, rtentry will notably shrink. More details: * architectural overview: https://reviews.freebsd.org/D24141 * list of the next changes: https://reviews.freebsd.org/D24232 Reviewed by: ae,glebius(initial version) Differential Revision: https://reviews.freebsd.org/D24232
2020-04-12 14:30:00 +00:00
uint64_t rts_nh_idx_alloc_failure; /* nexthop index alloc failure*/
uint64_t rts_nh_alloc_failure; /* nexthop allocation failure*/
Introduce scalable route multipath. This change is based on the nexthop objects landed in D24232. The change introduces the concept of nexthop groups. Each group contains the collection of nexthops with their relative weights and a dataplane-optimized structure to enable efficient nexthop selection. Simular to the nexthops, nexthop groups are immutable. Dataplane part gets compiled during group creation and is basically an array of nexthop pointers, compiled w.r.t their weights. With this change, `rt_nhop` field of `struct rtentry` contains either nexthop or nexthop group. They are distinguished by the presense of NHF_MULTIPATH flag. All dataplane lookup functions returns pointer to the nexthop object, leaving nexhop groups details inside routing subsystem. User-visible changes: The change is intended to be backward-compatible: all non-mpath operations should work as before with ROUTE_MPATH and net.route.multipath=1. All routes now comes with weight, default weight is 1, maximum is 2^24-1. Current maximum multipath group width is statically set to 64. This will become sysctl-tunable in the followup changes. Using functionality: * Recompile kernel with ROUTE_MPATH * set net.route.multipath to 1 route add -6 2001:db8::/32 2001:db8::2 -weight 10 route add -6 2001:db8::/32 2001:db8::3 -weight 20 netstat -6On Nexthop groups data Internet6: GrpIdx NhIdx Weight Slots Gateway Netif Refcnt 1 ------- ------- ------- --------------------------------------- --------- 1 13 10 1 2001:db8::2 vlan2 14 20 2 2001:db8::3 vlan2 Next steps: * Land outbound hashing for locally-originated routes ( D26523 ). * Fix net/bird multipath (net/frr seems to work fine) * Add ROUTE_MPATH to GENERIC * Set net.route.multipath=1 by default Tested by: olivier Reviewed by: glebius Relnotes: yes Differential Revision: https://reviews.freebsd.org/D26449
2020-10-03 10:47:17 +00:00
uint64_t rts_add_failure; /* # of route addition failures */
uint64_t rts_add_retry; /* # of route addition retries */
uint64_t rts_del_failure; /* # of route deletion failure */
uint64_t rts_del_retry; /* # of route deletion retries */
1994-05-24 10:09:53 +00:00
};
1994-05-24 10:09:53 +00:00
/*
* Structures for routing messages.
*/
struct rt_msghdr {
u_short rtm_msglen; /* to skip over non-understood messages */
u_char rtm_version; /* future binary compatibility */
u_char rtm_type; /* message type */
u_short rtm_index; /* index for associated ifp */
u_short _rtm_spare1;
1994-05-24 10:09:53 +00:00
int rtm_flags; /* flags, incl. kern & message, e.g. DONE */
int rtm_addrs; /* bitmask identifying sockaddrs in msg */
pid_t rtm_pid; /* identify sender */
int rtm_seq; /* for sender to identify action */
int rtm_errno; /* why failed */
int rtm_fmask; /* bitmask used in RTM_CHANGE message */
1994-05-24 10:09:53 +00:00
u_long rtm_inits; /* which metrics we are initializing */
struct rt_metrics rtm_rmx; /* metrics themselves */
};
#define RTM_VERSION 5 /* Up the ante and ignore older versions */
1994-05-24 10:09:53 +00:00
/*
* Message types.
*
* The format for each message is annotated below using the following
* identifiers:
*
* (1) struct rt_msghdr
* (2) struct ifa_msghdr
* (3) struct if_msghdr
* (4) struct ifma_msghdr
* (5) struct if_announcemsghdr
*
*/
#define RTM_ADD 0x1 /* (1) Add Route */
#define RTM_DELETE 0x2 /* (1) Delete Route */
#define RTM_CHANGE 0x3 /* (1) Change Metrics or flags */
#define RTM_GET 0x4 /* (1) Report Metrics */
#define RTM_LOSING 0x5 /* (1) Kernel Suspects Partitioning */
#define RTM_REDIRECT 0x6 /* (1) Told to use different route */
#define RTM_MISS 0x7 /* (1) Lookup failed on this address */
#define RTM_LOCK 0x8 /* (1) fix specified metrics */
/* 0x9 */
/* 0xa */
#define RTM_RESOLVE 0xb /* (1) req to resolve dst to LL addr */
#define RTM_NEWADDR 0xc /* (2) address being added to iface */
#define RTM_DELADDR 0xd /* (2) address being removed from iface */
#define RTM_IFINFO 0xe /* (3) iface going up/down etc. */
#define RTM_NEWMADDR 0xf /* (4) mcast group membership being added to if */
#define RTM_DELMADDR 0x10 /* (4) mcast group membership being deleted */
#define RTM_IFANNOUNCE 0x11 /* (5) iface arrival/departure */
#define RTM_IEEE80211 0x12 /* (5) IEEE80211 wireless event */
1994-05-24 10:09:53 +00:00
/*
* Bitmask values for rtm_inits and rmx_locks.
*/
1994-05-24 10:09:53 +00:00
#define RTV_MTU 0x1 /* init or lock _mtu */
#define RTV_HOPCOUNT 0x2 /* init or lock _hopcount */
#define RTV_EXPIRE 0x4 /* init or lock _expire */
1994-05-24 10:09:53 +00:00
#define RTV_RPIPE 0x8 /* init or lock _recvpipe */
#define RTV_SPIPE 0x10 /* init or lock _sendpipe */
#define RTV_SSTHRESH 0x20 /* init or lock _ssthresh */
#define RTV_RTT 0x40 /* init or lock _rtt */
#define RTV_RTTVAR 0x80 /* init or lock _rttvar */
#define RTV_WEIGHT 0x100 /* init or lock _weight */
1994-05-24 10:09:53 +00:00
/*
* Bitmask values for rtm_addrs.
1994-05-24 10:09:53 +00:00
*/
#define RTA_DST 0x1 /* destination sockaddr present */
#define RTA_GATEWAY 0x2 /* gateway sockaddr present */
#define RTA_NETMASK 0x4 /* netmask sockaddr present */
#define RTA_GENMASK 0x8 /* cloning mask sockaddr present */
#define RTA_IFP 0x10 /* interface name sockaddr present */
#define RTA_IFA 0x20 /* interface addr sockaddr present */
#define RTA_AUTHOR 0x40 /* sockaddr for author of redirect */
#define RTA_BRD 0x80 /* for NEWADDR, broadcast or p-p dest addr */
/*
* Index offsets for sockaddr array for alternate internal encoding.
*/
#define RTAX_DST 0 /* destination sockaddr present */
#define RTAX_GATEWAY 1 /* gateway sockaddr present */
#define RTAX_NETMASK 2 /* netmask sockaddr present */
#define RTAX_GENMASK 3 /* cloning mask sockaddr present */
#define RTAX_IFP 4 /* interface name sockaddr present */
#define RTAX_IFA 5 /* interface addr sockaddr present */
#define RTAX_AUTHOR 6 /* sockaddr for author of redirect */
#define RTAX_BRD 7 /* for NEWADDR, broadcast or p-p dest addr */
#define RTAX_MAX 8 /* size of array to allocate */
2020-04-25 09:25:06 +00:00
struct rtentry;
2020-04-16 17:53:23 +00:00
struct nhop_object;
typedef int rib_filter_f_t(const struct rtentry *, const struct nhop_object *,
void *);
1994-05-24 10:09:53 +00:00
struct rt_addrinfo {
int rti_addrs; /* Route RTF_ flags */
int rti_flags; /* Route RTF_ flags */
struct sockaddr *rti_info[RTAX_MAX]; /* Sockaddr data */
struct ifaddr *rti_ifa; /* value of rt_ifa addr */
struct ifnet *rti_ifp; /* route interface */
rib_filter_f_t *rti_filter; /* filter function */
void *rti_filterdata; /* filter parameters */
u_long rti_mflags; /* metrics RTV_ flags */
u_long rti_spare; /* Will be used for fib */
struct rt_metrics *rti_rmx; /* Pointer to route metrics */
1994-05-24 10:09:53 +00:00
};
/*
* This macro returns the size of a struct sockaddr when passed
* through a routing socket. Basically we round up sa_len to
* a multiple of sizeof(long), with a minimum of sizeof(long).
* The case sa_len == 0 should only apply to empty structures.
*/
#define SA_SIZE(sa) \
( (((struct sockaddr *)(sa))->sa_len == 0) ? \
sizeof(long) : \
1 + ( (((struct sockaddr *)(sa))->sa_len - 1) | (sizeof(long) - 1) ) )
#define sa_equal(a, b) ( \
(((const struct sockaddr *)(a))->sa_len == ((const struct sockaddr *)(b))->sa_len) && \
(bcmp((a), (b), ((const struct sockaddr *)(b))->sa_len) == 0))
#ifdef _KERNEL
#define RT_LINK_IS_UP(ifp) (!((ifp)->if_capabilities & IFCAP_LINKSTATE) \
|| (ifp)->if_link_state == LINK_STATE_UP)
#define RO_NHFREE(_ro) do { \
if ((_ro)->ro_nh) { \
NH_FREE((_ro)->ro_nh); \
(_ro)->ro_nh = NULL; \
} \
} while (0)
#define RO_INVALIDATE_CACHE(ro) do { \
if ((ro)->ro_lle != NULL) { \
LLE_FREE((ro)->ro_lle); \
(ro)->ro_lle = NULL; \
} \
if ((ro)->ro_nh != NULL) { \
NH_FREE((ro)->ro_nh); \
(ro)->ro_nh = NULL; \
} \
} while (0)
#define RO_GET_FAMILY(ro, dst) ((ro) != NULL && \
(ro)->ro_flags & RT_HAS_GW \
? (ro)->ro_dst.sa_family : (dst)->sa_family)
/*
* Validate a cached route based on a supplied cookie. If there is an
* out-of-date cache, simply free it. Update the generation number
* for the new allocation
*/
#define NH_VALIDATE(ro, cookiep, fibnum) do { \
rt_gen_t cookie = RT_GEN(fibnum, (ro)->ro_dst.sa_family); \
if (*(cookiep) != cookie) { \
RO_INVALIDATE_CACHE(ro); \
*(cookiep) = cookie; \
} \
} while (0)
struct ifmultiaddr;
struct rib_head;
void rt_ieee80211msg(struct ifnet *, int, void *, size_t);
2002-03-19 21:54:18 +00:00
void rt_ifmsg(struct ifnet *);
void rt_missmsg(int, struct rt_addrinfo *, int, int);
void rt_missmsg_fib(int, struct rt_addrinfo *, int, int, int);
int rt_addrmsg(int, struct ifaddr *, int);
int rt_routemsg(int, struct rtentry *, struct nhop_object *, int);
int rt_routemsg_info(int, struct rt_addrinfo *, int);
2002-03-19 21:54:18 +00:00
void rt_newmaddrmsg(int, struct ifmultiaddr *);
void rt_maskedcopy(const struct sockaddr *, struct sockaddr *,
const struct sockaddr *);
struct rib_head *rt_table_init(int, int, u_int);
void rt_table_destroy(struct rib_head *);
u_int rt_tables_get_gen(uint32_t table, sa_family_t family);
struct sockaddr *rtsock_fix_netmask(const struct sockaddr *dst,
const struct sockaddr *smask, struct sockaddr_storage *dmask);
void rt_updatemtu(struct ifnet *);
Add code to allow the system to handle multiple routing tables. This particular implementation is designed to be fully backwards compatible and to be MFC-able to 7.x (and 6.x) Currently the only protocol that can make use of the multiple tables is IPv4 Similar functionality exists in OpenBSD and Linux. From my notes: ----- One thing where FreeBSD has been falling behind, and which by chance I have some time to work on is "policy based routing", which allows different packet streams to be routed by more than just the destination address. Constraints: ------------ I want to make some form of this available in the 6.x tree (and by extension 7.x) , but FreeBSD in general needs it so I might as well do it in -current and back port the portions I need. One of the ways that this can be done is to have the ability to instantiate multiple kernel routing tables (which I will now refer to as "Forwarding Information Bases" or "FIBs" for political correctness reasons). Which FIB a particular packet uses to make the next hop decision can be decided by a number of mechanisms. The policies these mechanisms implement are the "Policies" referred to in "Policy based routing". One of the constraints I have if I try to back port this work to 6.x is that it must be implemented as a EXTENSION to the existing ABIs in 6.x so that third party applications do not need to be recompiled in timespan of the branch. This first version will not have some of the bells and whistles that will come with later versions. It will, for example, be limited to 16 tables in the first commit. Implementation method, Compatible version. (part 1) ------------------------------- For this reason I have implemented a "sufficient subset" of a multiple routing table solution in Perforce, and back-ported it to 6.x. (also in Perforce though not always caught up with what I have done in -current/P4). The subset allows a number of FIBs to be defined at compile time (8 is sufficient for my purposes in 6.x) and implements the changes needed to allow IPV4 to use them. I have not done the changes for ipv6 simply because I do not need it, and I do not have enough knowledge of ipv6 (e.g. neighbor discovery) needed to do it. Other protocol families are left untouched and should there be users with proprietary protocol families, they should continue to work and be oblivious to the existence of the extra FIBs. To understand how this is done, one must know that the current FIB code starts everything off with a single dimensional array of pointers to FIB head structures (One per protocol family), each of which in turn points to the trie of routes available to that family. The basic change in the ABI compatible version of the change is to extent that array to be a 2 dimensional array, so that instead of protocol family X looking at rt_tables[X] for the table it needs, it looks at rt_tables[Y][X] when for all protocol families except ipv4 Y is always 0. Code that is unaware of the change always just sees the first row of the table, which of course looks just like the one dimensional array that existed before. The entry points rtrequest(), rtalloc(), rtalloc1(), rtalloc_ign() are all maintained, but refer only to the first row of the array, so that existing callers in proprietary protocols can continue to do the "right thing". Some new entry points are added, for the exclusive use of ipv4 code called in_rtrequest(), in_rtalloc(), in_rtalloc1() and in_rtalloc_ign(), which have an extra argument which refers the code to the correct row. In addition, there are some new entry points (currently called rtalloc_fib() and friends) that check the Address family being looked up and call either rtalloc() (and friends) if the protocol is not IPv4 forcing the action to row 0 or to the appropriate row if it IS IPv4 (and that info is available). These are for calling from code that is not specific to any particular protocol. The way these are implemented would change in the non ABI preserving code to be added later. One feature of the first version of the code is that for ipv4, the interface routes show up automatically on all the FIBs, so that no matter what FIB you select you always have the basic direct attached hosts available to you. (rtinit() does this automatically). You CAN delete an interface route from one FIB should you want to but by default it's there. ARP information is also available in each FIB. It's assumed that the same machine would have the same MAC address, regardless of which FIB you are using to get to it. This brings us as to how the correct FIB is selected for an outgoing IPV4 packet. Firstly, all packets have a FIB associated with them. if nothing has been done to change it, it will be FIB 0. The FIB is changed in the following ways. Packets fall into one of a number of classes. 1/ locally generated packets, coming from a socket/PCB. Such packets select a FIB from a number associated with the socket/PCB. This in turn is inherited from the process, but can be changed by a socket option. The process in turn inherits it on fork. I have written a utility call setfib that acts a bit like nice.. setfib -3 ping target.example.com # will use fib 3 for ping. It is an obvious extension to make it a property of a jail but I have not done so. It can be achieved by combining the setfib and jail commands. 2/ packets received on an interface for forwarding. By default these packets would use table 0, (or possibly a number settable in a sysctl(not yet)). but prior to routing the firewall can inspect them (see below). (possibly in the future you may be able to associate a FIB with packets received on an interface.. An ifconfig arg, but not yet.) 3/ packets inspected by a packet classifier, which can arbitrarily associate a fib with it on a packet by packet basis. A fib assigned to a packet by a packet classifier (such as ipfw) would over-ride a fib associated by a more default source. (such as cases 1 or 2). 4/ a tcp listen socket associated with a fib will generate accept sockets that are associated with that same fib. 5/ Packets generated in response to some other packet (e.g. reset or icmp packets). These should use the FIB associated with the packet being reponded to. 6/ Packets generated during encapsulation. gif, tun and other tunnel interfaces will encapsulate using the FIB that was in effect withthe proces that set up the tunnel. thus setfib 1 ifconfig gif0 [tunnel instructions] will set the fib for the tunnel to use to be fib 1. Routing messages would be associated with their process, and thus select one FIB or another. messages from the kernel would be associated with the fib they refer to and would only be received by a routing socket associated with that fib. (not yet implemented) In addition Netstat has been edited to be able to cope with the fact that the array is now 2 dimensional. (It looks in system memory using libkvm (!)). Old versions of netstat see only the first FIB. In addition two sysctls are added to give: a) the number of FIBs compiled in (active) b) the default FIB of the calling process. Early testing experience: ------------------------- Basically our (IronPort's) appliance does this functionality already using ipfw fwd but that method has some drawbacks. For example, It can't fully simulate a routing table because it can't influence the socket's choice of local address when a connect() is done. Testing during the generating of these changes has been remarkably smooth so far. Multiple tables have co-existed with no notable side effects, and packets have been routes accordingly. ipfw has grown 2 new keywords: setfib N ip from anay to any count ip from any to any fib N In pf there seems to be a requirement to be able to give symbolic names to the fibs but I do not have that capacity. I am not sure if it is required. SCTP has interestingly enough built in support for this, called VRFs in Cisco parlance. it will be interesting to see how that handles it when it suddenly actually does something. Where to next: -------------------- After committing the ABI compatible version and MFCing it, I'd like to proceed in a forward direction in -current. this will result in some roto-tilling in the routing code. Firstly: the current code's idea of having a separate tree per protocol family, all of the same format, and pointed to by the 1 dimensional array is a bit silly. Especially when one considers that there is code that makes assumptions about every protocol having the same internal structures there. Some protocols don't WANT that sort of structure. (for example the whole idea of a netmask is foreign to appletalk). This needs to be made opaque to the external code. My suggested first change is to add routing method pointers to the 'domain' structure, along with information pointing the data. instead of having an array of pointers to uniform structures, there would be an array pointing to the 'domain' structures for each protocol address domain (protocol family), and the methods this reached would be called. The methods would have an argument that gives FIB number, but the protocol would be free to ignore it. When the ABI can be changed it raises the possibilty of the addition of a fib entry into the "struct route". Currently, the structure contains the sockaddr of the desination, and the resulting fib entry. To make this work fully, one could add a fib number so that given an address and a fib, one can find the third element, the fib entry. Interaction with the ARP layer/ LL layer would need to be revisited as well. Qing Li has been working on this already. This work was sponsored by Ironport Systems/Cisco Reviewed by: several including rwatson, bz and mlair (parts each) Obtained from: Ironport systems/Cisco
2008-05-09 23:03:00 +00:00
void rt_flushifroutes(struct ifnet *ifp);
Add code to allow the system to handle multiple routing tables. This particular implementation is designed to be fully backwards compatible and to be MFC-able to 7.x (and 6.x) Currently the only protocol that can make use of the multiple tables is IPv4 Similar functionality exists in OpenBSD and Linux. From my notes: ----- One thing where FreeBSD has been falling behind, and which by chance I have some time to work on is "policy based routing", which allows different packet streams to be routed by more than just the destination address. Constraints: ------------ I want to make some form of this available in the 6.x tree (and by extension 7.x) , but FreeBSD in general needs it so I might as well do it in -current and back port the portions I need. One of the ways that this can be done is to have the ability to instantiate multiple kernel routing tables (which I will now refer to as "Forwarding Information Bases" or "FIBs" for political correctness reasons). Which FIB a particular packet uses to make the next hop decision can be decided by a number of mechanisms. The policies these mechanisms implement are the "Policies" referred to in "Policy based routing". One of the constraints I have if I try to back port this work to 6.x is that it must be implemented as a EXTENSION to the existing ABIs in 6.x so that third party applications do not need to be recompiled in timespan of the branch. This first version will not have some of the bells and whistles that will come with later versions. It will, for example, be limited to 16 tables in the first commit. Implementation method, Compatible version. (part 1) ------------------------------- For this reason I have implemented a "sufficient subset" of a multiple routing table solution in Perforce, and back-ported it to 6.x. (also in Perforce though not always caught up with what I have done in -current/P4). The subset allows a number of FIBs to be defined at compile time (8 is sufficient for my purposes in 6.x) and implements the changes needed to allow IPV4 to use them. I have not done the changes for ipv6 simply because I do not need it, and I do not have enough knowledge of ipv6 (e.g. neighbor discovery) needed to do it. Other protocol families are left untouched and should there be users with proprietary protocol families, they should continue to work and be oblivious to the existence of the extra FIBs. To understand how this is done, one must know that the current FIB code starts everything off with a single dimensional array of pointers to FIB head structures (One per protocol family), each of which in turn points to the trie of routes available to that family. The basic change in the ABI compatible version of the change is to extent that array to be a 2 dimensional array, so that instead of protocol family X looking at rt_tables[X] for the table it needs, it looks at rt_tables[Y][X] when for all protocol families except ipv4 Y is always 0. Code that is unaware of the change always just sees the first row of the table, which of course looks just like the one dimensional array that existed before. The entry points rtrequest(), rtalloc(), rtalloc1(), rtalloc_ign() are all maintained, but refer only to the first row of the array, so that existing callers in proprietary protocols can continue to do the "right thing". Some new entry points are added, for the exclusive use of ipv4 code called in_rtrequest(), in_rtalloc(), in_rtalloc1() and in_rtalloc_ign(), which have an extra argument which refers the code to the correct row. In addition, there are some new entry points (currently called rtalloc_fib() and friends) that check the Address family being looked up and call either rtalloc() (and friends) if the protocol is not IPv4 forcing the action to row 0 or to the appropriate row if it IS IPv4 (and that info is available). These are for calling from code that is not specific to any particular protocol. The way these are implemented would change in the non ABI preserving code to be added later. One feature of the first version of the code is that for ipv4, the interface routes show up automatically on all the FIBs, so that no matter what FIB you select you always have the basic direct attached hosts available to you. (rtinit() does this automatically). You CAN delete an interface route from one FIB should you want to but by default it's there. ARP information is also available in each FIB. It's assumed that the same machine would have the same MAC address, regardless of which FIB you are using to get to it. This brings us as to how the correct FIB is selected for an outgoing IPV4 packet. Firstly, all packets have a FIB associated with them. if nothing has been done to change it, it will be FIB 0. The FIB is changed in the following ways. Packets fall into one of a number of classes. 1/ locally generated packets, coming from a socket/PCB. Such packets select a FIB from a number associated with the socket/PCB. This in turn is inherited from the process, but can be changed by a socket option. The process in turn inherits it on fork. I have written a utility call setfib that acts a bit like nice.. setfib -3 ping target.example.com # will use fib 3 for ping. It is an obvious extension to make it a property of a jail but I have not done so. It can be achieved by combining the setfib and jail commands. 2/ packets received on an interface for forwarding. By default these packets would use table 0, (or possibly a number settable in a sysctl(not yet)). but prior to routing the firewall can inspect them (see below). (possibly in the future you may be able to associate a FIB with packets received on an interface.. An ifconfig arg, but not yet.) 3/ packets inspected by a packet classifier, which can arbitrarily associate a fib with it on a packet by packet basis. A fib assigned to a packet by a packet classifier (such as ipfw) would over-ride a fib associated by a more default source. (such as cases 1 or 2). 4/ a tcp listen socket associated with a fib will generate accept sockets that are associated with that same fib. 5/ Packets generated in response to some other packet (e.g. reset or icmp packets). These should use the FIB associated with the packet being reponded to. 6/ Packets generated during encapsulation. gif, tun and other tunnel interfaces will encapsulate using the FIB that was in effect withthe proces that set up the tunnel. thus setfib 1 ifconfig gif0 [tunnel instructions] will set the fib for the tunnel to use to be fib 1. Routing messages would be associated with their process, and thus select one FIB or another. messages from the kernel would be associated with the fib they refer to and would only be received by a routing socket associated with that fib. (not yet implemented) In addition Netstat has been edited to be able to cope with the fact that the array is now 2 dimensional. (It looks in system memory using libkvm (!)). Old versions of netstat see only the first FIB. In addition two sysctls are added to give: a) the number of FIBs compiled in (active) b) the default FIB of the calling process. Early testing experience: ------------------------- Basically our (IronPort's) appliance does this functionality already using ipfw fwd but that method has some drawbacks. For example, It can't fully simulate a routing table because it can't influence the socket's choice of local address when a connect() is done. Testing during the generating of these changes has been remarkably smooth so far. Multiple tables have co-existed with no notable side effects, and packets have been routes accordingly. ipfw has grown 2 new keywords: setfib N ip from anay to any count ip from any to any fib N In pf there seems to be a requirement to be able to give symbolic names to the fibs but I do not have that capacity. I am not sure if it is required. SCTP has interestingly enough built in support for this, called VRFs in Cisco parlance. it will be interesting to see how that handles it when it suddenly actually does something. Where to next: -------------------- After committing the ABI compatible version and MFCing it, I'd like to proceed in a forward direction in -current. this will result in some roto-tilling in the routing code. Firstly: the current code's idea of having a separate tree per protocol family, all of the same format, and pointed to by the 1 dimensional array is a bit silly. Especially when one considers that there is code that makes assumptions about every protocol having the same internal structures there. Some protocols don't WANT that sort of structure. (for example the whole idea of a netmask is foreign to appletalk). This needs to be made opaque to the external code. My suggested first change is to add routing method pointers to the 'domain' structure, along with information pointing the data. instead of having an array of pointers to uniform structures, there would be an array pointing to the 'domain' structures for each protocol address domain (protocol family), and the methods this reached would be called. The methods would have an argument that gives FIB number, but the protocol would be free to ignore it. When the ABI can be changed it raises the possibilty of the addition of a fib entry into the "struct route". Currently, the structure contains the sockaddr of the desination, and the resulting fib entry. To make this work fully, one could add a fib number so that given an address and a fib, one can find the third element, the fib entry. Interaction with the ARP layer/ LL layer would need to be revisited as well. Qing Li has been working on this already. This work was sponsored by Ironport Systems/Cisco Reviewed by: several including rwatson, bz and mlair (parts each) Obtained from: Ironport systems/Cisco
2008-05-09 23:03:00 +00:00
/* XXX MRT NEW VERSIONS THAT USE FIBs
* For now the protocol indepedent versions are the same as the AF_INET ones
* but this will change..
*/
int rtioctl_fib(u_long, caddr_t, u_int);
Add code to allow the system to handle multiple routing tables. This particular implementation is designed to be fully backwards compatible and to be MFC-able to 7.x (and 6.x) Currently the only protocol that can make use of the multiple tables is IPv4 Similar functionality exists in OpenBSD and Linux. From my notes: ----- One thing where FreeBSD has been falling behind, and which by chance I have some time to work on is "policy based routing", which allows different packet streams to be routed by more than just the destination address. Constraints: ------------ I want to make some form of this available in the 6.x tree (and by extension 7.x) , but FreeBSD in general needs it so I might as well do it in -current and back port the portions I need. One of the ways that this can be done is to have the ability to instantiate multiple kernel routing tables (which I will now refer to as "Forwarding Information Bases" or "FIBs" for political correctness reasons). Which FIB a particular packet uses to make the next hop decision can be decided by a number of mechanisms. The policies these mechanisms implement are the "Policies" referred to in "Policy based routing". One of the constraints I have if I try to back port this work to 6.x is that it must be implemented as a EXTENSION to the existing ABIs in 6.x so that third party applications do not need to be recompiled in timespan of the branch. This first version will not have some of the bells and whistles that will come with later versions. It will, for example, be limited to 16 tables in the first commit. Implementation method, Compatible version. (part 1) ------------------------------- For this reason I have implemented a "sufficient subset" of a multiple routing table solution in Perforce, and back-ported it to 6.x. (also in Perforce though not always caught up with what I have done in -current/P4). The subset allows a number of FIBs to be defined at compile time (8 is sufficient for my purposes in 6.x) and implements the changes needed to allow IPV4 to use them. I have not done the changes for ipv6 simply because I do not need it, and I do not have enough knowledge of ipv6 (e.g. neighbor discovery) needed to do it. Other protocol families are left untouched and should there be users with proprietary protocol families, they should continue to work and be oblivious to the existence of the extra FIBs. To understand how this is done, one must know that the current FIB code starts everything off with a single dimensional array of pointers to FIB head structures (One per protocol family), each of which in turn points to the trie of routes available to that family. The basic change in the ABI compatible version of the change is to extent that array to be a 2 dimensional array, so that instead of protocol family X looking at rt_tables[X] for the table it needs, it looks at rt_tables[Y][X] when for all protocol families except ipv4 Y is always 0. Code that is unaware of the change always just sees the first row of the table, which of course looks just like the one dimensional array that existed before. The entry points rtrequest(), rtalloc(), rtalloc1(), rtalloc_ign() are all maintained, but refer only to the first row of the array, so that existing callers in proprietary protocols can continue to do the "right thing". Some new entry points are added, for the exclusive use of ipv4 code called in_rtrequest(), in_rtalloc(), in_rtalloc1() and in_rtalloc_ign(), which have an extra argument which refers the code to the correct row. In addition, there are some new entry points (currently called rtalloc_fib() and friends) that check the Address family being looked up and call either rtalloc() (and friends) if the protocol is not IPv4 forcing the action to row 0 or to the appropriate row if it IS IPv4 (and that info is available). These are for calling from code that is not specific to any particular protocol. The way these are implemented would change in the non ABI preserving code to be added later. One feature of the first version of the code is that for ipv4, the interface routes show up automatically on all the FIBs, so that no matter what FIB you select you always have the basic direct attached hosts available to you. (rtinit() does this automatically). You CAN delete an interface route from one FIB should you want to but by default it's there. ARP information is also available in each FIB. It's assumed that the same machine would have the same MAC address, regardless of which FIB you are using to get to it. This brings us as to how the correct FIB is selected for an outgoing IPV4 packet. Firstly, all packets have a FIB associated with them. if nothing has been done to change it, it will be FIB 0. The FIB is changed in the following ways. Packets fall into one of a number of classes. 1/ locally generated packets, coming from a socket/PCB. Such packets select a FIB from a number associated with the socket/PCB. This in turn is inherited from the process, but can be changed by a socket option. The process in turn inherits it on fork. I have written a utility call setfib that acts a bit like nice.. setfib -3 ping target.example.com # will use fib 3 for ping. It is an obvious extension to make it a property of a jail but I have not done so. It can be achieved by combining the setfib and jail commands. 2/ packets received on an interface for forwarding. By default these packets would use table 0, (or possibly a number settable in a sysctl(not yet)). but prior to routing the firewall can inspect them (see below). (possibly in the future you may be able to associate a FIB with packets received on an interface.. An ifconfig arg, but not yet.) 3/ packets inspected by a packet classifier, which can arbitrarily associate a fib with it on a packet by packet basis. A fib assigned to a packet by a packet classifier (such as ipfw) would over-ride a fib associated by a more default source. (such as cases 1 or 2). 4/ a tcp listen socket associated with a fib will generate accept sockets that are associated with that same fib. 5/ Packets generated in response to some other packet (e.g. reset or icmp packets). These should use the FIB associated with the packet being reponded to. 6/ Packets generated during encapsulation. gif, tun and other tunnel interfaces will encapsulate using the FIB that was in effect withthe proces that set up the tunnel. thus setfib 1 ifconfig gif0 [tunnel instructions] will set the fib for the tunnel to use to be fib 1. Routing messages would be associated with their process, and thus select one FIB or another. messages from the kernel would be associated with the fib they refer to and would only be received by a routing socket associated with that fib. (not yet implemented) In addition Netstat has been edited to be able to cope with the fact that the array is now 2 dimensional. (It looks in system memory using libkvm (!)). Old versions of netstat see only the first FIB. In addition two sysctls are added to give: a) the number of FIBs compiled in (active) b) the default FIB of the calling process. Early testing experience: ------------------------- Basically our (IronPort's) appliance does this functionality already using ipfw fwd but that method has some drawbacks. For example, It can't fully simulate a routing table because it can't influence the socket's choice of local address when a connect() is done. Testing during the generating of these changes has been remarkably smooth so far. Multiple tables have co-existed with no notable side effects, and packets have been routes accordingly. ipfw has grown 2 new keywords: setfib N ip from anay to any count ip from any to any fib N In pf there seems to be a requirement to be able to give symbolic names to the fibs but I do not have that capacity. I am not sure if it is required. SCTP has interestingly enough built in support for this, called VRFs in Cisco parlance. it will be interesting to see how that handles it when it suddenly actually does something. Where to next: -------------------- After committing the ABI compatible version and MFCing it, I'd like to proceed in a forward direction in -current. this will result in some roto-tilling in the routing code. Firstly: the current code's idea of having a separate tree per protocol family, all of the same format, and pointed to by the 1 dimensional array is a bit silly. Especially when one considers that there is code that makes assumptions about every protocol having the same internal structures there. Some protocols don't WANT that sort of structure. (for example the whole idea of a netmask is foreign to appletalk). This needs to be made opaque to the external code. My suggested first change is to add routing method pointers to the 'domain' structure, along with information pointing the data. instead of having an array of pointers to uniform structures, there would be an array pointing to the 'domain' structures for each protocol address domain (protocol family), and the methods this reached would be called. The methods would have an argument that gives FIB number, but the protocol would be free to ignore it. When the ABI can be changed it raises the possibilty of the addition of a fib entry into the "struct route". Currently, the structure contains the sockaddr of the desination, and the resulting fib entry. To make this work fully, one could add a fib number so that given an address and a fib, one can find the third element, the fib entry. Interaction with the ARP layer/ LL layer would need to be revisited as well. Qing Li has been working on this already. This work was sponsored by Ironport Systems/Cisco Reviewed by: several including rwatson, bz and mlair (parts each) Obtained from: Ironport systems/Cisco
2008-05-09 23:03:00 +00:00
Introduce nexthop objects and new routing KPI. This is the foundational change for the routing subsytem rearchitecture. More details and goals are available in https://reviews.freebsd.org/D24141 . This patch introduces concept of nexthop objects and new nexthop-based routing KPI. Nexthops are objects, containing all necessary information for performing the packet output decision. Output interface, mtu, flags, gw address goes there. For most of the cases, these objects will serve the same role as the struct rtentry is currently serving. Typically there will be low tens of such objects for the router even with multiple BGP full-views, as these objects will be shared between routing entries. This allows to store more information in the nexthop. New KPI: struct nhop_object *fib4_lookup(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, uint32_t flowid); struct nhop_object *fib6_lookup(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, uint32_t flowid); These 2 function are intended to replace all all flavours of <in_|in6_>rtalloc[1]<_ign><_fib>, mpath functions and the previous fib[46]-generation functions. Upon successful lookup, they return nexthop object which is guaranteed to exist within current NET_EPOCH. If longer lifetime is desired, one can specify NHR_REF as a flag and get a referenced version of the nexthop. Reference semantic closely resembles rtentry one, allowing sed-style conversion. Additionally, another 2 functions are introduced to support uRPF functionality inside variety of our firewalls. Their primary goal is to hide the multipath implementation details inside the routing subsystem, greatly simplifying firewalls implementation: int fib4_lookup_urpf(uint32_t fibnum, struct in_addr dst, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); int fib6_lookup_urpf(uint32_t fibnum, const struct in6_addr *dst6, uint32_t scopeid, uint32_t flags, const struct ifnet *src_if); All functions have a separate scopeid argument, paving way to eliminating IPv6 scope embedding and allowing to support IPv4 link-locals in the future. Structure changes: * rtentry gets new 'rt_nhop' pointer, slightly growing the overall size. * rib_head gets new 'rnh_preadd' callback pointer, slightly growing overall sz. Old KPI: During the transition state old and new KPI will coexists. As there are another 4-5 decent-sized conversion patches, it will probably take a couple of weeks. To support both KPIs, fields not required by the new KPI (most of rtentry) has to be kept, resulting in the temporary size increase. Once conversion is finished, rtentry will notably shrink. More details: * architectural overview: https://reviews.freebsd.org/D24141 * list of the next changes: https://reviews.freebsd.org/D24232 Reviewed by: ae,glebius(initial version) Differential Revision: https://reviews.freebsd.org/D24232
2020-04-12 14:30:00 +00:00
/* New API */
void rib_flush_routes_family(int family);
struct nhop_object *rib_lookup(uint32_t fibnum, const struct sockaddr *dst,
uint32_t flags, uint32_t flowid);
const char *rib_print_family(int family);
1994-05-24 10:09:53 +00:00
#endif
1994-08-21 05:11:48 +00:00
#endif