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* Copyright (c) 2009, 2010, 2013 Nicira, Inc.
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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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* http://www.apache.org/licenses/LICENSE-2.0
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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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#include "rtnetlink-link.h"
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#include <sys/socket.h>
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#include <linux/rtnetlink.h>
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#include "netlink-notifier.h"
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static struct nln *nln = NULL;
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static struct rtnetlink_link_change rtn_change;
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/* Parses a rtnetlink message 'buf' into 'change'. If 'buf' is unparseable,
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* leaves 'change' untouched and returns false. Otherwise, populates 'change'
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* and returns true. */
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rtnetlink_link_parse(struct ofpbuf *buf,
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struct rtnetlink_link_change *change)
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/* Policy for RTNLGRP_LINK messages.
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* There are *many* more fields in these messages, but currently we
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* only care about these fields. */
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static const struct nl_policy policy[] = {
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[IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
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[IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
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[IFLA_MTU] = { .type = NL_A_U32, .optional = true },
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[IFLA_ADDRESS] = { .type = NL_A_UNSPEC, .optional = true },
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struct nlattr *attrs[ARRAY_SIZE(policy)];
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parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
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policy, attrs, ARRAY_SIZE(policy));
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const struct nlmsghdr *nlmsg;
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const struct ifinfomsg *ifinfo;
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nlmsg = ofpbuf_data(buf);
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ifinfo = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *ifinfo);
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change->nlmsg_type = nlmsg->nlmsg_type;
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change->ifi_index = ifinfo->ifi_index;
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change->ifname = nl_attr_get_string(attrs[IFLA_IFNAME]);
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change->ifi_flags = ifinfo->ifi_flags;
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change->master_ifindex = (attrs[IFLA_MASTER]
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? nl_attr_get_u32(attrs[IFLA_MASTER])
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change->mtu = (attrs[IFLA_MTU]
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? nl_attr_get_u32(attrs[IFLA_MTU])
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if (attrs[IFLA_ADDRESS] &&
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nl_attr_get_size(attrs[IFLA_ADDRESS]) == ETH_ALEN) {
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memcpy(change->addr, nl_attr_get(attrs[IFLA_ADDRESS]), ETH_ALEN);
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memset(change->addr, 0, ETH_ALEN);
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rtnetlink_link_parse_cb(struct ofpbuf *buf, void *change)
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return rtnetlink_link_parse(buf, change);
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/* Registers 'cb' to be called with auxiliary data 'aux' with network device
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* change notifications. The notifier is stored in 'notifier', which the
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* caller must not modify or free.
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* This is probably not the function that you want. You should probably be
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* using dpif_port_poll() or netdev_change_seq(), which unlike this function
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* are not Linux-specific.
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* Returns an initialized nln_notifier if successful, NULL otherwise. */
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struct nln_notifier *
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rtnetlink_link_notifier_create(rtnetlink_link_notify_func *cb, void *aux)
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nln = nln_create(NETLINK_ROUTE, RTNLGRP_LINK, rtnetlink_link_parse_cb,
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return nln_notifier_create(nln, (nln_notify_func *) cb, aux);
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/* Destroys 'notifier', which must have previously been created with
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* rtnetlink_link_notifier_register(). */
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rtnetlink_link_notifier_destroy(struct nln_notifier *notifier)
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nln_notifier_destroy(notifier);
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/* Calls all of the registered notifiers, passing along any as-yet-unreported
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* netdev change events. */
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rtnetlink_link_run(void)
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/* Causes poll_block() to wake up when network device change notifications are
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rtnetlink_link_wait(void)