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rtnetlink: Remove LINK specific messages from rtnetlink

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Abstracted rtnetlink so that it may be used for messages other than
RTM LINK messages.  Created a new rtnetlink-link module which
specifically deals with these kinds of messages and follows the old
rtnetlink API.
This commit is contained in:
Ethan Jackson
2010-12-21 13:44:37 -08:00
parent 5601839c45
commit 21d6e22eee
7 changed files with 286 additions and 119 deletions
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145
lib/rtnetlink.c
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@@ -19,9 +19,6 @@
#include "rtnetlink.h"
#include <errno.h>
#include <sys/socket.h>
#include <linux/rtnetlink.h>
#include <net/if.h>
#include <poll.h>
#include "coverage.h"
@@ -34,33 +31,54 @@ VLOG_DEFINE_THIS_MODULE(rtnetlink);
COVERAGE_DEFINE(rtnetlink_changed);
/* rtnetlink socket. */
static struct nl_sock *notify_sock;
static void rtnetlink_report(struct rtnetlink *rtn, void *change);
/* All registered notifiers. */
static struct list all_notifiers = LIST_INITIALIZER(&all_notifiers);
struct rtnetlink {
struct nl_sock *notify_sock; /* Rtnetlink socket. */
struct list all_notifiers; /* All rtnetlink notifiers. */
static void rtnetlink_report_change(const struct nlmsghdr *,
const struct ifinfomsg *,
struct nlattr *attrs[]);
static void rtnetlink_report_notify_error(void);
/* Passed in by rtnetlink_create(). */
int multicast_group; /* Multicast group we listen on. */
rtnetlink_parse_func *parse; /* Message parsing function. */
void *change; /* Change passed to parse. */
};
/* 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.
/* Creates an rtnetlink handle which may be used to manage change
* notifications. The created handle will listen for rtnetlink messages on
* 'multicast_group'. Incoming messages will be parsed with 'parse' which will
* be passed 'change' as an argument. */
struct rtnetlink *
rtnetlink_create(int multicast_group, rtnetlink_parse_func *parse,
void *change)
{
struct rtnetlink *rtn;
rtn = xzalloc(sizeof *rtn);
rtn->notify_sock = 0;
rtn->multicast_group = multicast_group;
rtn->parse = parse;
rtn->change = change;
list_init(&rtn->all_notifiers);
return rtn;
}
/* Registers 'cb' to be called with auxiliary data 'aux' with 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_monitor_create(), which unlike this
* function are not Linux-specific.
* This is probably not the function you want. You should probably be using
* message specific notifiers like rtnetlink_link_notifier_register().
*
* Returns 0 if successful, otherwise a positive errno value. */
int
rtnetlink_notifier_register(struct rtnetlink_notifier *notifier,
rtnetlink_notifier_register(struct rtnetlink *rtn,
struct rtnetlink_notifier *notifier,
rtnetlink_notify_func *cb, void *aux)
{
if (!notify_sock) {
int error = nl_sock_create(NETLINK_ROUTE, RTNLGRP_LINK, 0, 0,
&notify_sock);
if (!rtn->notify_sock) {
int error = nl_sock_create(NETLINK_ROUTE, rtn->multicast_group, 0, 0,
&rtn->notify_sock);
if (error) {
VLOG_WARN("could not create rtnetlink socket: %s",
strerror(error));
@@ -69,10 +87,10 @@ rtnetlink_notifier_register(struct rtnetlink_notifier *notifier,
} else {
/* Catch up on notification work so that the new notifier won't
* receive any stale notifications. */
rtnetlink_notifier_run();
rtnetlink_notifier_run(rtn);
}
list_push_back(&all_notifiers, &notifier->node);
list_push_back(&rtn->all_notifiers, &notifier->node);
notifier->cb = cb;
notifier->aux = aux;
return 0;
@@ -81,52 +99,38 @@ rtnetlink_notifier_register(struct rtnetlink_notifier *notifier,
/* Cancels notification on 'notifier', which must have previously been
* registered with rtnetlink_notifier_register(). */
void
rtnetlink_notifier_unregister(struct rtnetlink_notifier *notifier)
rtnetlink_notifier_unregister(struct rtnetlink *rtn,
struct rtnetlink_notifier *notifier)
{
list_remove(&notifier->node);
if (list_is_empty(&all_notifiers)) {
nl_sock_destroy(notify_sock);
notify_sock = NULL;
if (list_is_empty(&rtn->all_notifiers)) {
nl_sock_destroy(rtn->notify_sock);
rtn->notify_sock = NULL;
}
}
/* Calls all of the registered notifiers, passing along any as-yet-unreported
* netdev change events. */
* change events. */
void
rtnetlink_notifier_run(void)
rtnetlink_notifier_run(struct rtnetlink *rtn)
{
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
if (!notify_sock) {
if (!rtn->notify_sock) {
return;
}
for (;;) {
/* 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 rtnetlink_policy[] = {
[IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
[IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
};
struct nlattr *attrs[ARRAY_SIZE(rtnetlink_policy)];
struct ofpbuf *buf;
int error;
error = nl_sock_recv(notify_sock, &buf, false);
error = nl_sock_recv(rtn->notify_sock, &buf, false);
if (!error) {
if (nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
rtnetlink_policy,
attrs, ARRAY_SIZE(rtnetlink_policy))) {
struct ifinfomsg *ifinfo;
ifinfo = (void *) ((char *) buf->data + NLMSG_HDRLEN);
rtnetlink_report_change(buf->data, ifinfo, attrs);
if (rtn->parse(buf, rtn->change)) {
rtnetlink_report(rtn, rtn->change);
} else {
VLOG_WARN_RL(&rl, "received bad rtnl message");
rtnetlink_report_notify_error();
rtnetlink_report(rtn, NULL);
}
ofpbuf_delete(buf);
} else if (error == EAGAIN) {
@@ -138,48 +142,31 @@ rtnetlink_notifier_run(void)
VLOG_WARN_RL(&rl, "error reading rtnetlink socket: %s",
strerror(error));
}
rtnetlink_report_notify_error();
rtnetlink_report(rtn, NULL);
}
}
}
/* Causes poll_block() to wake up when network device change notifications are
* ready. */
/* Causes poll_block() to wake up when change notifications are ready. */
void
rtnetlink_notifier_wait(void)
rtnetlink_notifier_wait(struct rtnetlink *rtn)
{
if (notify_sock) {
nl_sock_wait(notify_sock, POLLIN);
if (rtn->notify_sock) {
nl_sock_wait(rtn->notify_sock, POLLIN);
}
}
static void
rtnetlink_report_change(const struct nlmsghdr *nlmsg,
const struct ifinfomsg *ifinfo,
struct nlattr *attrs[])
{
struct rtnetlink_notifier *notifier;
struct rtnetlink_change change;
COVERAGE_INC(rtnetlink_changed);
change.nlmsg_type = nlmsg->nlmsg_type;
change.ifi_index = ifinfo->ifi_index;
change.ifname = nl_attr_get_string(attrs[IFLA_IFNAME]);
change.master_ifindex = (attrs[IFLA_MASTER]
? nl_attr_get_u32(attrs[IFLA_MASTER]) : 0);
LIST_FOR_EACH (notifier, node, &all_notifiers) {
notifier->cb(&change, notifier->aux);
}
}
static void
rtnetlink_report_notify_error(void)
rtnetlink_report(struct rtnetlink *rtn, void *change)
{
struct rtnetlink_notifier *notifier;
LIST_FOR_EACH (notifier, node, &all_notifiers) {
notifier->cb(NULL, notifier->aux);
if (change) {
COVERAGE_INC(rtnetlink_changed);
}
LIST_FOR_EACH (notifier, node, &rtn->all_notifiers) {
notifier->cb(change, notifier->aux);
}
}