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freebsd-skq/sys/netinet/in_fib.c
melifaro ca13483a3c Merge helper fib* functions used for basic lookups. 
Vast majority of rtalloc(9) users require only basic info from
route table (e.g. "does the rtentry interface match with the interface
  I have?". "what is the MTU?", "Give me the IPv4 source address to use",
  etc..).
Instead of hand-rolling lookups, checking if rtentry is up, valid,
  dealing with IPv6 mtu, finding "address" ifp (almost never done right),
  provide easy-to-use API hiding all the complexity and returning the
  needed info into small on-stack structure.

This change also helps hiding route subsystem internals (locking, direct
  rtentry accesses).
Additionaly, using this API improves lookup performance since rtentry is not
  locked.
(This is safe, since all the rtentry changes happens under both radix WLOCK
  and rtentry WLOCK).

Sponsored by:	Yandex LLC
2015-12-08 10:50:03 +00:00

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/*-
* Copyright (c) 2015
* Alexander V. Chernikov <melifaro@FreeBSD.org>
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_route.h"
#include "opt_mpath.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/vnet.h>
#ifdef RADIX_MPATH
#include <net/radix_mpath.h>
#endif
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_fib.h>
#ifdef INET
static void fib4_rte_to_nh_basic(struct rtentry *rte, struct in_addr dst,
uint32_t flags, struct nhop4_basic *pnh4);
static void fib4_rte_to_nh_extended(struct rtentry *rte, struct in_addr dst,
uint32_t flags, struct nhop4_extended *pnh4);
#define RNTORT(p) ((struct rtentry *)(p))
static void
fib4_rte_to_nh_basic(struct rtentry *rte, struct in_addr dst,
uint32_t flags, struct nhop4_basic *pnh4)
{
struct sockaddr_in *gw;
if ((flags & NHR_IFAIF) != 0)
pnh4->nh_ifp = rte->rt_ifa->ifa_ifp;
else
pnh4->nh_ifp = rte->rt_ifp;
pnh4->nh_mtu = min(rte->rt_mtu, rte->rt_ifp->if_mtu);
if (rte->rt_flags & RTF_GATEWAY) {
gw = (struct sockaddr_in *)rte->rt_gateway;
pnh4->nh_addr = gw->sin_addr;
} else
pnh4->nh_addr = dst;
/* Set flags */
pnh4->nh_flags = fib_rte_to_nh_flags(rte->rt_flags);
gw = (struct sockaddr_in *)rt_key(rte);
if (gw->sin_addr.s_addr == 0)
pnh4->nh_flags |= NHF_DEFAULT;
/* TODO: Handle RTF_BROADCAST here */
}
static void
fib4_rte_to_nh_extended(struct rtentry *rte, struct in_addr dst,
uint32_t flags, struct nhop4_extended *pnh4)
{
struct sockaddr_in *gw;
struct in_ifaddr *ia;
pnh4->nh_ifp = rte->rt_ifa->ifa_ifp;
pnh4->nh_mtu = min(rte->rt_mtu, rte->rt_ifp->if_mtu);
if (rte->rt_flags & RTF_GATEWAY) {
gw = (struct sockaddr_in *)rte->rt_gateway;
pnh4->nh_addr = gw->sin_addr;
} else
pnh4->nh_addr = dst;
/* Set flags */
pnh4->nh_flags = fib_rte_to_nh_flags(rte->rt_flags);
gw = (struct sockaddr_in *)rt_key(rte);
if (gw->sin_addr.s_addr == 0)
pnh4->nh_flags |= NHF_DEFAULT;
/* XXX: Set RTF_BROADCAST if GW address is broadcast */
ia = ifatoia(rte->rt_ifa);
pnh4->nh_src = IA_SIN(ia)->sin_addr;
}
/*
* Performs IPv4 route table lookup on @dst. Returns 0 on success.
* Stores nexthop info provided @pnh4 structure.
* Note that
* - nh_ifp cannot be safely dereferenced
* - nh_ifp represents logical transmit interface (rt_ifp) (e.g. if
* looking up address on interface "ix0" pointer to "lo0" interface
* will be returned instead of "ix0")
* - nh_ifp represents "address" interface if NHR_IFAIF flag is passed
* - howewer mtu from "transmit" interface will be returned.
*/
int
fib4_lookup_nh_basic(uint32_t fibnum, struct in_addr dst, uint32_t flags,
uint32_t flowid, struct nhop4_basic *pnh4)
{
struct radix_node_head *rh;
struct radix_node *rn;
struct sockaddr_in sin;
struct rtentry *rte;
KASSERT((fibnum < rt_numfibs), ("fib4_lookup_nh_basic: bad fibnum"));
rh = rt_tables_get_rnh(fibnum, AF_INET);
if (rh == NULL)
return (ENOENT);
/* Prepare lookup key */
memset(&sin, 0, sizeof(sin));
sin.sin_len = sizeof(struct sockaddr_in);
sin.sin_addr = dst;
RADIX_NODE_HEAD_RLOCK(rh);
rn = rh->rnh_matchaddr((void *)&sin, rh);
if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
rte = RNTORT(rn);
/* Ensure route & ifp is UP */
if (RT_LINK_IS_UP(rte->rt_ifp)) {
fib4_rte_to_nh_basic(rte, dst, flags, pnh4);
RADIX_NODE_HEAD_RUNLOCK(rh);
return (0);
}
}
RADIX_NODE_HEAD_RUNLOCK(rh);
return (ENOENT);
}
/*
* Performs IPv4 route table lookup on @dst. Returns 0 on success.
* Stores extende nexthop info provided @pnh4 structure.
* Note that
* - nh_ifp cannot be safely dereferenced unless NHR_REF is specified.
* - in that case you need to call fib4_free_nh_ext()
* - nh_ifp represents logical transmit interface (rt_ifp) (e.g. if
* looking up address of interface "ix0" pointer to "lo0" interface
* will be returned instead of "ix0")
* - nh_ifp represents "address" interface if NHR_IFAIF flag is passed
* - howewer mtu from "transmit" interface will be returned.
*/
int
fib4_lookup_nh_ext(uint32_t fibnum, struct in_addr dst, uint32_t flowid,
uint32_t flags, struct nhop4_extended *pnh4)
{
struct radix_node_head *rh;
struct radix_node *rn;
struct sockaddr_in sin;
struct rtentry *rte;
KASSERT((fibnum < rt_numfibs), ("fib4_lookup_nh_ext: bad fibnum"));
rh = rt_tables_get_rnh(fibnum, AF_INET);
if (rh == NULL)
return (ENOENT);
/* Prepare lookup key */
memset(&sin, 0, sizeof(sin));
sin.sin_len = sizeof(struct sockaddr_in);
sin.sin_addr = dst;
RADIX_NODE_HEAD_RLOCK(rh);
rn = rh->rnh_matchaddr((void *)&sin, rh);
if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0)) {
rte = RNTORT(rn);
/* Ensure route & ifp is UP */
if (RT_LINK_IS_UP(rte->rt_ifp)) {
fib4_rte_to_nh_extended(rte, dst, flags, pnh4);
if ((flags & NHR_REF) != 0) {
/* TODO: lwref on egress ifp's ? */
}
RADIX_NODE_HEAD_RUNLOCK(rh);
return (0);
}
}
RADIX_NODE_HEAD_RUNLOCK(rh);
return (ENOENT);
}
void
fib4_free_nh_ext(uint32_t fibnum, struct nhop4_extended *pnh4)
{
}
#endif
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