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/*
* Copyright (c) 2009, 2010, 2013, 2015, 2016 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "rtnetlink.h"
#include <sys/socket.h>
#include <linux/rtnetlink.h>
#include <net/if.h>
#include "netlink.h"
#include "netlink-notifier.h"
#include "openvswitch/ofpbuf.h"
#include "packets.h"
static struct nln *nln = NULL;
static struct rtnetlink_change rtn_change;
/* Returns true if the given netlink msg type corresponds to RTNLGRP_LINK. */
bool
rtnetlink_type_is_rtnlgrp_link(uint16_t type)
{
return type == RTM_NEWLINK || type == RTM_DELLINK;
}
/* Returns true if the given netlink msg type corresponds to
* RTNLGRP_IPV4_IFADDR or RTNLGRP_IPV6_IFADDR. */
bool
rtnetlink_type_is_rtnlgrp_addr(uint16_t type)
{
return type == RTM_NEWADDR || type == RTM_DELADDR;
}
/* Parses a rtnetlink message 'buf' into 'change'. If 'buf' is unparseable,
* leaves 'change' untouched and returns false. Otherwise, populates 'change'
* and returns true. */
bool
rtnetlink_parse(struct ofpbuf *buf, struct rtnetlink_change *change)
{
const struct nlmsghdr *nlmsg = buf->data;
bool parsed = false;
if (rtnetlink_type_is_rtnlgrp_link(nlmsg->nlmsg_type)) {
/* Policy for RTNLGRP_LINK messages.
*
* There are *many* more fields in these messages, but currently we
* only care about these fields. */
static const struct nl_policy policy[] = {
[IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
[IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
[IFLA_MTU] = { .type = NL_A_U32, .optional = true },
[IFLA_ADDRESS] = { .type = NL_A_UNSPEC, .optional = true },
};
struct nlattr *attrs[ARRAY_SIZE(policy)];
parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
policy, attrs, ARRAY_SIZE(policy));
if (parsed) {
const struct ifinfomsg *ifinfo;
ifinfo = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *ifinfo);
change->nlmsg_type = nlmsg->nlmsg_type;
change->if_index = ifinfo->ifi_index;
change->ifname = nl_attr_get_string(attrs[IFLA_IFNAME]);
change->ifi_flags = ifinfo->ifi_flags;
change->master_ifindex = (attrs[IFLA_MASTER]
? nl_attr_get_u32(attrs[IFLA_MASTER])
: 0);
change->mtu = (attrs[IFLA_MTU]
? nl_attr_get_u32(attrs[IFLA_MTU])
: 0);
if (attrs[IFLA_ADDRESS] &&
nl_attr_get_size(attrs[IFLA_ADDRESS]) == ETH_ADDR_LEN) {
memcpy(&change->mac, nl_attr_get(attrs[IFLA_ADDRESS]),
ETH_ADDR_LEN);
} else {
memset(&change->mac, 0, ETH_ADDR_LEN);
}
}
} else if (rtnetlink_type_is_rtnlgrp_addr(nlmsg->nlmsg_type)) {
/* Policy for RTNLGRP_IPV4_IFADDR/RTNLGRP_IPV6_IFADDR messages.
*
* There are *many* more fields in these messages, but currently we
* only care about these fields. */
static const struct nl_policy policy[] = {
[IFA_LABEL] = { .type = NL_A_STRING, .optional = true },
};
struct nlattr *attrs[ARRAY_SIZE(policy)];
parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifaddrmsg),
policy, attrs, ARRAY_SIZE(policy));
if (parsed) {
const struct ifaddrmsg *ifaddr;
ifaddr = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *ifaddr);
change->nlmsg_type = nlmsg->nlmsg_type;
change->if_index = ifaddr->ifa_index;
change->ifname = (attrs[IFA_LABEL]
? nl_attr_get_string(attrs[IFA_LABEL])
: NULL);
}
}
return parsed;
}
/* Return RTNLGRP_LINK on success, 0 on parse error. */
static int
rtnetlink_parse_cb(struct ofpbuf *buf, void *change)
{
return rtnetlink_parse(buf, change) ? RTNLGRP_LINK : 0;
}
/* Registers 'cb' to be called with auxiliary data 'aux' with network device
* change notifications. The notifier is stored in 'notifier', which the
* caller must not modify or free.
*
* This is probably not the function that you want. You should probably be
* using dpif_port_poll() or netdev_change_seq(), which unlike this function
* are not Linux-specific.
*
* xxx Joins more multicast groups when needed.
*
* Returns an initialized nln_notifier if successful, NULL otherwise. */
struct nln_notifier *
rtnetlink_notifier_create(rtnetlink_notify_func *cb, void *aux)
{
if (!nln) {
nln = nln_create(NETLINK_ROUTE, rtnetlink_parse_cb, &rtn_change);
}
return nln_notifier_create(nln, RTNLGRP_LINK, (nln_notify_func *) cb, aux);
}
/* Destroys 'notifier', which must have previously been created with
* rtnetlink_notifier_register(). */
void
rtnetlink_notifier_destroy(struct nln_notifier *notifier)
{
nln_notifier_destroy(notifier);
}
/* Calls all of the registered notifiers, passing along any as-yet-unreported
* netdev change events. */
void
rtnetlink_run(void)
{
if (nln) {
nln_run(nln);
}
}
/* Causes poll_block() to wake up when network device change notifications are
* ready. */
void
rtnetlink_wait(void)
{
if (nln) {
nln_wait(nln);
}
}
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