mirror of
https://github.com/openvswitch/ovs
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491 lines
12 KiB
C
491 lines
12 KiB
C
/*
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* Copyright (c) 2011 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include "route-table.h"
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#include <assert.h>
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#include <arpa/inet.h>
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#include <sys/socket.h>
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#include <linux/rtnetlink.h>
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#include <net/if.h>
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#include "hash.h"
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#include "hmap.h"
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#include "netlink.h"
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#include "netlink-socket.h"
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#include "ofpbuf.h"
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#include "rtnetlink.h"
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#include "rtnetlink-link.h"
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#include "vlog.h"
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VLOG_DEFINE_THIS_MODULE(route_table);
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struct route_data {
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/* Copied from struct rtmsg. */
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unsigned char rtm_dst_len;
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/* Extracted from Netlink attributes. */
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uint32_t rta_dst; /* Destination in host byte order. 0 if missing. */
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int rta_oif; /* Output interface index. */
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};
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/* A digested version of a route message sent down by the kernel to indicate
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* that a route has changed. */
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struct route_table_msg {
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bool relevant; /* Should this message be processed? */
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int nlmsg_type; /* e.g. RTM_NEWROUTE, RTM_DELROUTE. */
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struct route_data rd; /* Data parsed from this message. */
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};
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struct route_node {
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struct hmap_node node; /* Node in route_map. */
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struct route_data rd; /* Data associated with this node. */
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};
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struct name_node {
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struct hmap_node node; /* Node in name_map. */
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uint32_t ifi_index; /* Kernel interface index. */
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char ifname[IFNAMSIZ]; /* Interface name. */
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};
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static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
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static unsigned int register_count = 0;
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static struct rtnetlink *rtn = NULL;
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static struct route_table_msg rtmsg;
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static struct rtnetlink_notifier route_notifier;
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static struct rtnetlink_notifier name_notifier;
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static bool route_table_valid = false;
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static bool name_table_valid = false;
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static struct hmap route_map;
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static struct hmap name_map;
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static int route_table_reset(void);
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static void route_table_handle_msg(const struct route_table_msg *);
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static bool route_table_parse(struct ofpbuf *, struct route_table_msg *);
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static void route_table_change(const struct route_table_msg *, void *);
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static struct route_node *route_node_lookup(const struct route_data *);
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static struct route_node *route_node_lookup_by_ip(uint32_t ip);
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static void route_map_clear(void);
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static uint32_t hash_route_data(const struct route_data *);
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static void name_table_init(void);
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static void name_table_uninit(void);
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static int name_table_reset(void);
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static void name_table_change(const struct rtnetlink_link_change *, void *);
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static void name_map_clear(void);
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static struct name_node *name_node_lookup(int ifi_index);
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/* Populates 'name' with the name of the interface traffic destined for 'ip'
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* is likely to egress out of (see route_table_get_ifindex).
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*
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* Returns true if successful, otherwise false. */
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bool
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route_table_get_name(ovs_be32 ip, char name[IFNAMSIZ])
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{
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int ifindex;
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if (!name_table_valid) {
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name_table_reset();
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}
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if (route_table_get_ifindex(ip, &ifindex)) {
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struct name_node *nn;
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nn = name_node_lookup(ifindex);
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if (nn) {
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strncpy(name, nn->ifname, IFNAMSIZ);
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return true;
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}
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}
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return false;
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}
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/* Populates 'ifindex' with the interface index traffic destined for 'ip' is
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* likely to egress. There is no hard guarantee that traffic destined for 'ip'
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* will egress out the specified interface. 'ifindex' may refer to an
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* interface which is not physical (such as a bridge port).
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*
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* Returns true if successful, otherwise false. */
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bool
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route_table_get_ifindex(ovs_be32 ip_, int *ifindex)
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{
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struct route_node *rn;
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uint32_t ip = ntohl(ip_);
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*ifindex = 0;
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if (!route_table_valid) {
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route_table_reset();
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}
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rn = route_node_lookup_by_ip(ip);
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if (rn) {
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*ifindex = rn->rd.rta_oif;
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return true;
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}
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/* Choose a default route. */
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HMAP_FOR_EACH(rn, node, &route_map) {
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if (rn->rd.rta_dst == 0 && rn->rd.rtm_dst_len == 0) {
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*ifindex = rn->rd.rta_oif;
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return true;
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}
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}
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return false;
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}
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/* Users of the route_table module should register themselves with this
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* function before making any other route_table function calls. */
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void
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route_table_register(void)
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{
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if (!register_count) {
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rtnetlink_parse_func *pf;
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rtnetlink_notify_func *nf;
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assert(!rtn);
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pf = (rtnetlink_parse_func *) route_table_parse;
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nf = (rtnetlink_notify_func *) route_table_change;
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rtn = rtnetlink_create(RTNLGRP_IPV4_ROUTE, pf, &rtmsg);
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rtnetlink_notifier_register(rtn, &route_notifier, nf, NULL);
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hmap_init(&route_map);
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route_table_reset();
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name_table_init();
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}
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register_count++;
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}
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/* Users of the route_table module should unregister themselves with this
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* function when they will no longer be making any more route_table fuction
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* calls. */
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void
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route_table_unregister(void)
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{
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register_count--;
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if (!register_count) {
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rtnetlink_destroy(rtn);
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rtn = NULL;
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route_map_clear();
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hmap_destroy(&route_map);
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name_table_uninit();
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}
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}
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/* Run periodically to update the locally maintained routing table. */
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void
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route_table_run(void)
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{
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if (rtn) {
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rtnetlink_link_notifier_run();
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rtnetlink_notifier_run(rtn);
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}
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}
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/* Causes poll_block() to wake up when route_table updates are required. */
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void
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route_table_wait(void)
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{
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if (rtn) {
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rtnetlink_link_notifier_wait();
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rtnetlink_notifier_wait(rtn);
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}
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}
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static int
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route_table_reset(void)
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{
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int error;
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struct nl_dump dump;
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struct rtgenmsg *rtmsg;
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struct ofpbuf request, reply;
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static struct nl_sock *rtnl_sock;
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route_map_clear();
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route_table_valid = true;
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error = nl_sock_create(NETLINK_ROUTE, &rtnl_sock);
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if (error) {
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VLOG_WARN_RL(&rl, "failed to reset routing table, "
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"cannot create RTNETLINK_ROUTE socket");
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return error;
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}
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ofpbuf_init(&request, 0);
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nl_msg_put_nlmsghdr(&request, sizeof *rtmsg, RTM_GETROUTE, NLM_F_REQUEST);
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rtmsg = ofpbuf_put_zeros(&request, sizeof *rtmsg);
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rtmsg->rtgen_family = AF_INET;
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nl_dump_start(&dump, rtnl_sock, &request);
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while (nl_dump_next(&dump, &reply)) {
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struct route_table_msg msg;
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if (route_table_parse(&reply, &msg)) {
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route_table_handle_msg(&msg);
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}
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}
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error = nl_dump_done(&dump);
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nl_sock_destroy(rtnl_sock);
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return error;
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}
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static bool
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route_table_parse(struct ofpbuf *buf, struct route_table_msg *change)
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{
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bool parsed;
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static const struct nl_policy policy[] = {
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[RTA_DST] = { .type = NL_A_U32, .optional = true },
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[RTA_OIF] = { .type = NL_A_U32, .optional = false },
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};
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static struct nlattr *attrs[ARRAY_SIZE(policy)];
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parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct rtmsg),
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policy, attrs, ARRAY_SIZE(policy));
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if (parsed) {
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const struct rtmsg *rtm;
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const struct nlmsghdr *nlmsg;
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nlmsg = buf->data;
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rtm = (const struct rtmsg *) ((const char *) buf->data + NLMSG_HDRLEN);
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if (rtm->rtm_family != AF_INET) {
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VLOG_DBG_RL(&rl, "received non AF_INET rtnetlink route message");
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return false;
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}
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memset(change, 0, sizeof *change);
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change->relevant = true;
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if (rtm->rtm_scope == RT_SCOPE_NOWHERE) {
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change->relevant = false;
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}
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if (rtm->rtm_type != RTN_UNICAST &&
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rtm->rtm_type != RTN_LOCAL) {
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change->relevant = false;
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}
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change->nlmsg_type = nlmsg->nlmsg_type;
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change->rd.rtm_dst_len = rtm->rtm_dst_len;
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change->rd.rta_oif = nl_attr_get_u32(attrs[RTA_OIF]);
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if (attrs[RTA_DST]) {
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change->rd.rta_dst = ntohl(nl_attr_get_be32(attrs[RTA_DST]));
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}
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} else {
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VLOG_DBG_RL(&rl, "received unparseable rtnetlink route message");
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}
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return parsed;
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}
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static void
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route_table_change(const struct route_table_msg *change OVS_UNUSED,
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void *aux OVS_UNUSED)
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{
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route_table_valid = false;
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}
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static void
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route_table_handle_msg(const struct route_table_msg *change)
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{
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if (change->relevant && change->nlmsg_type == RTM_NEWROUTE &&
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!route_node_lookup(&change->rd)) {
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struct route_node *rn;
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rn = xzalloc(sizeof *rn);
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memcpy(&rn->rd, &change->rd, sizeof change->rd);
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hmap_insert(&route_map, &rn->node, hash_route_data(&rn->rd));
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}
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}
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static struct route_node *
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route_node_lookup(const struct route_data *rd)
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{
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struct route_node *rn;
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HMAP_FOR_EACH_WITH_HASH(rn, node, hash_route_data(rd), &route_map) {
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if (!memcmp(&rn->rd, rd, sizeof *rd)) {
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return rn;
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}
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}
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return NULL;
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}
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static struct route_node *
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route_node_lookup_by_ip(uint32_t ip)
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{
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int dst_len;
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struct route_node *rn, *rn_ret;
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dst_len = -1;
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rn_ret = NULL;
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HMAP_FOR_EACH(rn, node, &route_map) {
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uint32_t mask = 0xffffffff << (32 - rn->rd.rtm_dst_len);
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if (rn->rd.rta_dst == 0 && rn->rd.rtm_dst_len == 0) {
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/* Default route. */
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continue;
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}
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if (rn->rd.rtm_dst_len > dst_len &&
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(ip & mask) == (rn->rd.rta_dst & mask)) {
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rn_ret = rn;
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dst_len = rn->rd.rtm_dst_len;
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}
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}
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return rn_ret;
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}
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static void
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route_map_clear(void)
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{
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struct route_node *rn, *rn_next;
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HMAP_FOR_EACH_SAFE(rn, rn_next, node, &route_map) {
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hmap_remove(&route_map, &rn->node);
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free(rn);
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}
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}
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static uint32_t
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hash_route_data(const struct route_data *rd)
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{
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return hash_bytes(rd, sizeof *rd, 0);
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}
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/* name_table . */
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static void
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name_table_init(void)
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{
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hmap_init(&name_map);
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rtnetlink_link_notifier_register(&name_notifier, name_table_change, NULL);
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name_table_valid = false;
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}
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static void
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name_table_uninit(void)
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{
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rtnetlink_link_notifier_unregister(&name_notifier);
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name_map_clear();
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hmap_destroy(&name_map);
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}
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static int
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name_table_reset(void)
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{
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int error;
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struct nl_dump dump;
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struct rtgenmsg *rtmsg;
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struct ofpbuf request, reply;
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static struct nl_sock *rtnl_sock;
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name_table_valid = true;
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name_map_clear();
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error = nl_sock_create(NETLINK_ROUTE, &rtnl_sock);
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if (error) {
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VLOG_WARN_RL(&rl, "failed to create NETLINK_ROUTE socket");
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return error;
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}
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ofpbuf_init(&request, 0);
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nl_msg_put_nlmsghdr(&request, sizeof *rtmsg, RTM_GETLINK, NLM_F_REQUEST);
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rtmsg = ofpbuf_put_zeros(&request, sizeof *rtmsg);
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rtmsg->rtgen_family = AF_INET;
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nl_dump_start(&dump, rtnl_sock, &request);
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while (nl_dump_next(&dump, &reply)) {
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struct rtnetlink_link_change change;
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if (rtnetlink_link_parse(&reply, &change)
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&& change.nlmsg_type == RTM_NEWLINK
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&& !name_node_lookup(change.ifi_index)) {
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struct name_node *nn;
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nn = xzalloc(sizeof *nn);
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nn->ifi_index = change.ifi_index;
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strncpy(nn->ifname, change.ifname, IFNAMSIZ);
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nn->ifname[IFNAMSIZ - 1] = '\0';
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hmap_insert(&name_map, &nn->node, hash_int(nn->ifi_index, 0));
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}
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}
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nl_sock_destroy(rtnl_sock);
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return nl_dump_done(&dump);
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}
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static void
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name_table_change(const struct rtnetlink_link_change *change OVS_UNUSED,
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void *aux OVS_UNUSED)
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{
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/* Changes to interface status can cause routing table changes that some
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* versions of the linux kernel do not advertise for some reason. */
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route_table_valid = false;
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name_table_valid = false;
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}
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static struct name_node *
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name_node_lookup(int ifi_index)
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{
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struct name_node *nn;
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HMAP_FOR_EACH_WITH_HASH(nn, node, hash_int(ifi_index, 0), &name_map) {
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if (nn->ifi_index == ifi_index) {
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return nn;
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}
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}
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return NULL;
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}
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static void
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name_map_clear(void)
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{
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struct name_node *nn, *nn_next;
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HMAP_FOR_EACH_SAFE(nn, nn_next, node, &name_map) {
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hmap_remove(&name_map, &nn->node);
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free(nn);
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}
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}
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