6e6b3f7cbc
1. separating L2 tables (ARP, NDP) from the L3 routing tables
2. removing as much locking dependencies among these layers as
possible to allow for some parallelism in the search operations
3. simplify the logic in the routing code,
The most notable end result is the obsolescent of the route
cloning (RTF_CLONING) concept, which translated into code reduction
in both IPv4 ARP and IPv6 NDP related modules, and size reduction in
struct rtentry{}. The change in design obsoletes the semantics of
RTF_CLONING, RTF_WASCLONE and RTF_LLINFO routing flags. The userland
applications such as "arp" and "ndp" have been modified to reflect
those changes. The output from "netstat -r" shows only the routing
entries.
Quite a few developers have contributed to this project in the
past: Glebius Smirnoff, Luigi Rizzo, Alessandro Cerri, and
Andre Oppermann. And most recently:
- Kip Macy revised the locking code completely, thus completing
the last piece of the puzzle, Kip has also been conducting
active functional testing
- Sam Leffler has helped me improving/refactoring the code, and
provided valuable reviews
- Julian Elischer setup the perforce tree for me and has helped
me maintaining that branch before the svn conversion
344 lines
8.6 KiB
C
344 lines
8.6 KiB
C
/* $KAME: radix_mpath.c,v 1.17 2004/11/08 10:29:39 itojun Exp $ */
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/*
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* Copyright (C) 2001 WIDE Project.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* THE AUTHORS DO NOT GUARANTEE THAT THIS SOFTWARE DOES NOT INFRINGE
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* ANY OTHERS' INTELLECTUAL PROPERTIES. IN NO EVENT SHALL THE AUTHORS
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* BE LIABLE FOR ANY INFRINGEMENT OF ANY OTHERS' INTELLECTUAL
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* PROPERTIES.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/socket.h>
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#include <sys/domain.h>
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#include <sys/syslog.h>
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#include <net/radix.h>
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#include <net/radix_mpath.h>
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#include <net/route.h>
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#include <net/if.h>
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#include <net/if_var.h>
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/*
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* give some jitter to hash, to avoid synchronization between routers
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*/
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static uint32_t hashjitter;
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int
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rn_mpath_capable(struct radix_node_head *rnh)
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{
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return rnh->rnh_multipath;
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}
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struct radix_node *
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rn_mpath_next(struct radix_node *rn)
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{
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struct radix_node *next;
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if (!rn->rn_dupedkey)
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return NULL;
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next = rn->rn_dupedkey;
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if (rn->rn_mask == next->rn_mask)
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return next;
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else
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return NULL;
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}
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u_int32_t
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rn_mpath_count(struct radix_node *rn)
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{
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u_int32_t i;
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i = 1;
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while ((rn = rn_mpath_next(rn)) != NULL)
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i++;
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return i;
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}
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struct rtentry *
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rt_mpath_matchgate(struct rtentry *rt, struct sockaddr *gate)
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{
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struct radix_node *rn;
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if (!rn_mpath_next((struct radix_node *)rt))
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return rt;
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if (!gate)
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return NULL;
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/* beyond here, we use rn as the master copy */
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rn = (struct radix_node *)rt;
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do {
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rt = (struct rtentry *)rn;
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/*
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* we are removing an address alias that has
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* the same prefix as another address
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* we need to compare the interface address because
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* rt_gateway is a special sockadd_dl structure
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*/
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if (rt->rt_gateway->sa_family == AF_LINK) {
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if (!memcmp(rt->rt_ifa->ifa_addr, gate, gate->sa_len))
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break;
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} else {
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if (rt->rt_gateway->sa_len == gate->sa_len &&
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!memcmp(rt->rt_gateway, gate, gate->sa_len))
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break;
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}
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} while ((rn = rn_mpath_next(rn)) != NULL);
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return (struct rtentry *)rn;
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}
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/*
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* go through the chain and unlink "rt" from the list
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* the caller will free "rt"
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*/
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int
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rt_mpath_deldup(struct rtentry *headrt, struct rtentry *rt)
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{
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struct radix_node *t, *tt;
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if (!headrt || !rt)
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return (0);
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t = (struct radix_node *)headrt;
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tt = rn_mpath_next(t);
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while (tt) {
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if (tt == (struct radix_node *)rt) {
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t->rn_dupedkey = tt->rn_dupedkey;
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tt->rn_dupedkey = NULL;
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tt->rn_flags &= ~RNF_ACTIVE;
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tt[1].rn_flags &= ~RNF_ACTIVE;
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return (1);
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}
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t = tt;
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tt = rn_mpath_next((struct radix_node *)t);
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}
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return (0);
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}
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/*
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* check if we have the same key/mask/gateway on the table already.
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*/
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int
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rt_mpath_conflict(struct radix_node_head *rnh, struct rtentry *rt,
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struct sockaddr *netmask)
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{
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struct radix_node *rn, *rn1;
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struct rtentry *rt1;
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char *p, *q, *eq;
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int same, l, skip;
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rn = (struct radix_node *)rt;
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rn1 = rnh->rnh_lookup(rt_key(rt), netmask, rnh);
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if (!rn1 || rn1->rn_flags & RNF_ROOT)
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return 0;
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/*
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* unlike other functions we have in this file, we have to check
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* all key/mask/gateway as rnh_lookup can match less specific entry.
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*/
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rt1 = (struct rtentry *)rn1;
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/* compare key. */
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if (rt_key(rt1)->sa_len != rt_key(rt)->sa_len ||
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bcmp(rt_key(rt1), rt_key(rt), rt_key(rt1)->sa_len))
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goto different;
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/* key was the same. compare netmask. hairy... */
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if (rt_mask(rt1) && netmask) {
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skip = rnh->rnh_treetop->rn_offset;
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if (rt_mask(rt1)->sa_len > netmask->sa_len) {
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/*
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* as rt_mask(rt1) is made optimal by radix.c,
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* there must be some 1-bits on rt_mask(rt1)
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* after netmask->sa_len. therefore, in
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* this case, the entries are different.
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*/
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if (rt_mask(rt1)->sa_len > skip)
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goto different;
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else {
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/* no bits to compare, i.e. same*/
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goto maskmatched;
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}
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}
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l = rt_mask(rt1)->sa_len;
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if (skip > l) {
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/* no bits to compare, i.e. same */
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goto maskmatched;
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}
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p = (char *)rt_mask(rt1);
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q = (char *)netmask;
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if (bcmp(p + skip, q + skip, l - skip))
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goto different;
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/*
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* need to go through all the bit, as netmask is not
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* optimal and can contain trailing 0s
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*/
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eq = (char *)netmask + netmask->sa_len;
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q += l;
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same = 1;
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while (eq > q)
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if (*q++) {
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same = 0;
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break;
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}
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if (!same)
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goto different;
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} else if (!rt_mask(rt1) && !netmask)
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; /* no mask to compare, i.e. same */
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else {
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/* one has mask and the other does not, different */
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goto different;
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}
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maskmatched:
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/* key/mask were the same. compare gateway for all multipaths */
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do {
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rt1 = (struct rtentry *)rn1;
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/* sanity: no use in comparing the same thing */
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if (rn1 == rn)
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continue;
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if (rt1->rt_gateway->sa_family == AF_LINK) {
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if (rt1->rt_ifa->ifa_addr->sa_len != rt->rt_ifa->ifa_addr->sa_len ||
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bcmp(rt1->rt_ifa->ifa_addr, rt->rt_ifa->ifa_addr,
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rt1->rt_ifa->ifa_addr->sa_len))
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continue;
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} else {
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if (rt1->rt_gateway->sa_len != rt->rt_gateway->sa_len ||
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bcmp(rt1->rt_gateway, rt->rt_gateway,
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rt1->rt_gateway->sa_len))
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continue;
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}
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/* all key/mask/gateway are the same. conflicting entry. */
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return EEXIST;
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} while ((rn1 = rn_mpath_next(rn1)) != NULL);
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different:
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return 0;
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}
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void
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rtalloc_mpath_fib(struct route *ro, u_int32_t hash, u_int fibnum)
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{
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struct radix_node *rn0, *rn;
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u_int32_t n;
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/*
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* XXX we don't attempt to lookup cached route again; what should
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* be done for sendto(3) case?
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*/
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if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP))
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return;
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ro->ro_rt = rtalloc1_fib(&ro->ro_dst, 1, 0, fibnum);
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/* if the route does not exist or it is not multipath, don't care */
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if (ro->ro_rt == NULL)
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return;
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if (rn_mpath_next((struct radix_node *)ro->ro_rt) == NULL) {
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RT_UNLOCK(ro->ro_rt);
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return;
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}
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/* beyond here, we use rn as the master copy */
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rn0 = rn = (struct radix_node *)ro->ro_rt;
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n = rn_mpath_count(rn0);
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/* gw selection by Modulo-N Hash (RFC2991) XXX need improvement? */
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hash += hashjitter;
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hash %= n;
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while (hash-- > 0 && rn) {
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/* stay within the multipath routes */
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if (rn->rn_dupedkey && rn->rn_mask != rn->rn_dupedkey->rn_mask)
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break;
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rn = rn->rn_dupedkey;
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}
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/* XXX try filling rt_gwroute and avoid unreachable gw */
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/* if gw selection fails, use the first match (default) */
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if (!rn) {
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RT_UNLOCK(ro->ro_rt);
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return;
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}
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RTFREE_LOCKED(ro->ro_rt);
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ro->ro_rt = (struct rtentry *)rn;
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RT_LOCK(ro->ro_rt);
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RT_ADDREF(ro->ro_rt);
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RT_UNLOCK(ro->ro_rt);
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}
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extern int in6_inithead(void **head, int off);
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extern int in_inithead(void **head, int off);
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#ifdef INET
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int
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rn4_mpath_inithead(void **head, int off)
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{
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struct radix_node_head *rnh;
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hashjitter = arc4random();
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if (in_inithead(head, off) == 1) {
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rnh = (struct radix_node_head *)*head;
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rnh->rnh_multipath = 1;
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return 1;
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} else
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return 0;
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}
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#endif
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#ifdef INET6
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int
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rn6_mpath_inithead(void **head, int off)
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{
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struct radix_node_head *rnh;
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hashjitter = arc4random();
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if (in6_inithead(head, off) == 1) {
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rnh = (struct radix_node_head *)*head;
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rnh->rnh_multipath = 1;
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return 1;
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} else
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return 0;
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}
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#endif
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