OpenBSD-4.6/sys/net/radix_mpath.c
/* $OpenBSD: radix_mpath.c,v 1.17 2009/03/02 14:39:24 claudio Exp $ */
/* $KAME: radix_mpath.c,v 1.13 2002/10/28 21:05:59 itojun Exp $ */
/*
* Copyright (C) 2001 WIDE Project.
* 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 project 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 PROJECT 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 PROJECT 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.
* THE AUTHORS DO NOT GUARANTEE THAT THIS SOFTWARE DOES NOT INFRINGE
* ANY OTHERS' INTELLECTUAL PROPERTIES. IN NO EVENT SHALL THE AUTHORS
* BE LIABLE FOR ANY INFRINGEMENT OF ANY OTHERS' INTELLECTUAL
* PROPERTIES.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#define M_DONTWAIT M_NOWAIT
#include <sys/domain.h>
#include <sys/syslog.h>
#include <net/radix.h>
#include <net/radix_mpath.h>
#include <net/route.h>
#include <dev/rndvar.h>
#include <netinet/in.h>
extern int ipmultipath;
extern int ip6_multipath;
u_int32_t rn_mpath_hash(struct route *, u_int32_t *);
/*
* give some jitter to hash, to avoid synchronization between routers
*/
static u_int32_t hashjitter;
#ifdef RN_DEBUG
extern struct radix_node *rn_clist;
#endif
int
rn_mpath_capable(struct radix_node_head *rnh)
{
return rnh->rnh_multipath;
}
struct radix_node *
rn_mpath_next(struct radix_node *rn, int all)
{
struct radix_node *next;
struct rtentry *rt = (struct rtentry *)rn;
if (!rn->rn_dupedkey)
return NULL;
next = rn->rn_dupedkey;
if (rn->rn_mask == next->rn_mask && (all ||
rt->rt_priority == ((struct rtentry *)next)->rt_priority))
return next;
else
return NULL;
}
struct radix_node *
rn_mpath_prio(struct radix_node *rn, u_int8_t prio)
{
struct radix_node *prev = rn;
struct rtentry *rt;
if (prio == RTP_ANY)
return (rn);
while (rn) {
/* different netmask -> different route */
if (rn->rn_mask != prev->rn_mask)
return (prev);
rt = (struct rtentry *)rn;
if (rt->rt_priority == prio)
return (rn);
if (rt->rt_priority > prio)
/* list is sorted return last more prefered entry */
return (prev);
prev = rn;
rn = rn->rn_dupedkey;
}
return (prev);
}
void
rn_mpath_reprio(struct radix_node *rn, int newprio)
{
struct radix_node *prev = rn->rn_p;
struct radix_node *next = rn->rn_dupedkey;
struct radix_node *t, *tt, *saved_tt, *head;
struct rtentry *rt = (struct rtentry *)rn;
int mid, oldprio, prioinv = 0;
oldprio = rt->rt_priority;
rt->rt_priority = newprio;
/* same prio, no change needed */
if (oldprio == newprio)
return;
if (rn_mpath_next(rn, 1) == NULL) {
/* no need to move node, route is alone */
if (prev->rn_mask != rn->rn_mask)
return;
/* ... or route is last and prio gets bigger */
if (oldprio < newprio)
return;
}
/* remove node from dupedkey list and reinsert at correct place */
if (prev->rn_dupedkey == rn) {
prev->rn_dupedkey = next;
if (next)
next->rn_p = prev;
else
next = prev;
} else {
if (next == NULL)
panic("next == NULL");
next->rn_p = prev;
if (prev->rn_l == rn)
prev->rn_l = next;
else
prev->rn_r = next;
}
/* re-insert rn at the right spot, so first rewind to the head */
for (tt = next; tt->rn_p->rn_dupedkey == tt; tt = tt->rn_p)
;
saved_tt = tt;
/*
* Stolen from radix.c rn_addroute().
* This is nasty code with a certain amount of magic and dragons.
* t is the element where the re-priorized rn is inserted -- before
* or after depending on prioinv. saved_tt points to the head of the
* dupedkey chain and tt is a bit of a helper
*
* First we skip with tt to the start of the mpath group then we
* search the right spot to enter our node.
*/
for (; tt; tt = tt->rn_dupedkey)
if (rn->rn_mask == tt->rn_mask)
break;
head = tt; /* store current head entry for rn_mklist check */
tt = rn_mpath_prio(tt, newprio);
if (((struct rtentry *)tt)->rt_priority != newprio) {
if (((struct rtentry *)tt)->rt_priority > newprio)
prioinv = 1;
t = tt;
} else {
mid = rn_mpath_count(tt) / 2;
do {
t = tt;
tt = rn_mpath_next(tt, 0);
} while (tt && --mid > 0);
}
/* insert rn before or after t depending on prioinv, tt and saved_tt */
if (tt == saved_tt && prioinv) {
/* link in at head of list */
rn->rn_dupedkey = tt;
rn->rn_p = tt->rn_p;
tt->rn_p = rn;
if (rn->rn_p->rn_l == tt)
rn->rn_p->rn_l = rn;
else
rn->rn_p->rn_r = rn;
} else if (prioinv == 1) {
rn->rn_dupedkey = t;
t->rn_p->rn_dupedkey = rn;
rn->rn_p = t->rn_p;
t->rn_p = rn;
} else {
rn->rn_dupedkey = t->rn_dupedkey;
t->rn_dupedkey = rn;
rn->rn_p = t;
if (rn->rn_dupedkey)
rn->rn_dupedkey->rn_p = rn;
}
#ifdef RN_DEBUG
/* readd at head of creation list */
for (t = rn_clist; t && t->rn_ybro != rn; t = t->rn_ybro)
;
if (t)
t->rn_ybro = rn->rn_ybro;
rn->rn_ybro = rn_clist;
rn_clist = rn;
#endif
if (rn->rn_mklist && rn->rn_flags & RNF_NORMAL) {
/* the rn_mklist needs to be fixed if the best route changed */
if (rn->rn_mklist->rm_leaf != rn) {
if (rn->rn_mklist->rm_leaf->rn_p == rn)
/* changed route is now best */
rn->rn_mklist->rm_leaf = rn;
} else {
if (rn->rn_dupedkey != head)
/* rn moved behind head, so head is new head */
rn->rn_mklist->rm_leaf = head;
}
}
}
int
rn_mpath_count(struct radix_node *rn)
{
int i;
i = 1;
while ((rn = rn_mpath_next(rn, 0)) != NULL)
i++;
return i;
}
struct rtentry *
rt_mpath_matchgate(struct rtentry *rt, struct sockaddr *gate, u_int8_t prio)
{
struct radix_node *rn = (struct radix_node *)rt;
do {
rt = (struct rtentry *)rn;
/* first find routes with correct priority */
if (prio != RTP_ANY &&
(rt->rt_priority & RTP_MASK) != (prio & RTP_MASK))
continue;
/*
* if gate is set it must be compared, if not set the route
* must be a non-multipath one.
*/
if (!gate && !rn_mpath_next(rn, 0))
return rt;
if (!gate)
return NULL;
if (!rt->rt_gateway)
continue;
if (rt->rt_gateway->sa_len == gate->sa_len &&
!memcmp(rt->rt_gateway, gate, gate->sa_len))
break;
} while ((rn = rn_mpath_next(rn, 1)) != NULL);
return (struct rtentry *)rn;
}
/*
* check if we have the same key/mask/gateway on the table already.
*/
int
rt_mpath_conflict(struct radix_node_head *rnh, struct rtentry *rt,
struct sockaddr *netmask, int mpathok)
{
struct radix_node *rn, *rn1;
struct rtentry *rt1;
char *p, *q, *eq;
int same, l, skip;
rn = (struct radix_node *)rt;
rn1 = rnh->rnh_lookup(rt_key(rt), netmask, rnh);
if (!rn1 || rn1->rn_flags & RNF_ROOT)
return 0;
/*
* unlike other functions we have in this file, we have to check
* all key/mask/gateway as rnh_lookup can match less specific entry.
*/
rt1 = (struct rtentry *)rn1;
/* compare key. */
if (rt_key(rt1)->sa_len != rt_key(rt)->sa_len ||
bcmp(rt_key(rt1), rt_key(rt), rt_key(rt1)->sa_len))
goto different;
/* key was the same. compare netmask. hairy... */
if (rt_mask(rt1) && netmask) {
skip = rnh->rnh_treetop->rn_off;
if (rt_mask(rt1)->sa_len > netmask->sa_len) {
/*
* as rt_mask(rt1) is made optimal by radix.c,
* there must be some 1-bits on rt_mask(rt1)
* after netmask->sa_len. therefore, in
* this case, the entries are different.
*/
if (rt_mask(rt1)->sa_len > skip)
goto different;
else {
/* no bits to compare, i.e. same*/
goto maskmatched;
}
}
l = rt_mask(rt1)->sa_len;
if (skip > l) {
/* no bits to compare, i.e. same */
goto maskmatched;
}
p = (char *)rt_mask(rt1);
q = (char *)netmask;
if (bcmp(p + skip, q + skip, l - skip))
goto different;
/*
* need to go through all the bit, as netmask is not
* optimal and can contain trailing 0s
*/
eq = (char *)netmask + netmask->sa_len;
q += l;
same = 1;
while (eq > q)
if (*q++) {
same = 0;
break;
}
if (!same)
goto different;
} else if (!rt_mask(rt1) && !netmask)
; /* no mask to compare, i.e. same */
else {
/* one has mask and the other does not, different */
goto different;
}
maskmatched:
if (!mpathok && rt1->rt_priority == rt->rt_priority)
return EEXIST;
rn1 = rn_mpath_prio((struct radix_node *)rt1, rt->rt_priority);
/* key/mask were the same. compare gateway for all multipaths */
do {
rt1 = (struct rtentry *)rn1;
/* sanity: no use in comparing the same thing */
if (rn1 == rn)
continue;
if (rt1->rt_gateway->sa_len != rt->rt_gateway->sa_len ||
bcmp(rt1->rt_gateway, rt->rt_gateway,
rt1->rt_gateway->sa_len))
continue;
/* check the route priority */
if (rt1->rt_priority != rt->rt_priority)
continue;
/* all key/mask/gateway are the same. conflicting entry. */
return EEXIST;
} while ((rn1 = rn_mpath_next(rn1, 0)) != NULL);
different:
return 0;
}
/*
* allocate a route, potentially using multipath to select the peer.
*/
void
rtalloc_mpath(struct route *ro, u_int32_t *srcaddrp, u_int tableid)
{
#if defined(INET) || defined(INET6)
struct radix_node *rn;
int hash, npaths, threshold;
#endif
/*
* return a cached entry if it is still valid, otherwise we increase
* the risk of disrupting local flows.
*/
if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP))
return;
ro->ro_rt = rtalloc1(&ro->ro_dst, 1, tableid);
/* if the route does not exist or it is not multipath, don't care */
if (!ro->ro_rt || !(ro->ro_rt->rt_flags & RTF_MPATH))
return;
/* check if multipath routing is enabled for the specified protocol */
if (!(0
#ifdef INET
|| (ipmultipath && ro->ro_dst.sa_family == AF_INET)
#endif
#ifdef INET6
|| (ip6_multipath && ro->ro_dst.sa_family == AF_INET6)
#endif
))
return;
#if defined(INET) || defined(INET6)
/* gw selection by Hash-Threshold (RFC 2992) */
rn = (struct radix_node *)ro->ro_rt;
npaths = rn_mpath_count(rn);
hash = rn_mpath_hash(ro, srcaddrp) & 0xffff;
threshold = 1 + (0xffff / npaths);
while (hash > threshold && rn) {
/* stay within the multipath routes */
if (rn_mpath_next(rn, 0) == NULL)
break;
rn = rn->rn_dupedkey;
hash -= threshold;
}
/* XXX try filling rt_gwroute and avoid unreachable gw */
/* if gw selection fails, use the first match (default) */
if (!rn)
return;
rtfree(ro->ro_rt);
ro->ro_rt = (struct rtentry *)rn;
ro->ro_rt->rt_refcnt++;
#endif
}
int
rn_mpath_inithead(void **head, int off)
{
struct radix_node_head *rnh;
while (hashjitter == 0)
hashjitter = arc4random();
if (rn_inithead(head, off) == 1) {
rnh = (struct radix_node_head *)*head;
rnh->rnh_multipath = 1;
return 1;
} else
return 0;
}
/*
* hash function based on pf_hash in pf.c
*/
#define mix(a,b,c) \
do { \
a -= b; a -= c; a ^= (c >> 13); \
b -= c; b -= a; b ^= (a << 8); \
c -= a; c -= b; c ^= (b >> 13); \
a -= b; a -= c; a ^= (c >> 12); \
b -= c; b -= a; b ^= (a << 16); \
c -= a; c -= b; c ^= (b >> 5); \
a -= b; a -= c; a ^= (c >> 3); \
b -= c; b -= a; b ^= (a << 10); \
c -= a; c -= b; c ^= (b >> 15); \
} while (0)
u_int32_t
rn_mpath_hash(struct route *ro, u_int32_t *srcaddrp)
{
u_int32_t a, b, c;
a = b = 0x9e3779b9;
c = hashjitter;
switch (ro->ro_dst.sa_family) {
#ifdef INET
case AF_INET:
{
struct sockaddr_in *sin_dst;
sin_dst = (struct sockaddr_in *)&ro->ro_dst;
a += sin_dst->sin_addr.s_addr;
b += srcaddrp ? srcaddrp[0] : 0;
mix(a, b, c);
break;
}
#endif /* INET */
#ifdef INET6
case AF_INET6:
{
struct sockaddr_in6 *sin6_dst;
sin6_dst = (struct sockaddr_in6 *)&ro->ro_dst;
a += sin6_dst->sin6_addr.s6_addr32[0];
b += sin6_dst->sin6_addr.s6_addr32[2];
c += srcaddrp ? srcaddrp[0] : 0;
mix(a, b, c);
a += sin6_dst->sin6_addr.s6_addr32[1];
b += sin6_dst->sin6_addr.s6_addr32[3];
c += srcaddrp ? srcaddrp[1] : 0;
mix(a, b, c);
a += sin6_dst->sin6_addr.s6_addr32[2];
b += sin6_dst->sin6_addr.s6_addr32[1];
c += srcaddrp ? srcaddrp[2] : 0;
mix(a, b, c);
a += sin6_dst->sin6_addr.s6_addr32[3];
b += sin6_dst->sin6_addr.s6_addr32[0];
c += srcaddrp ? srcaddrp[3] : 0;
mix(a, b, c);
break;
}
#endif /* INET6 */
}
return c;
}