OVS源码bridge_run分析

bridge_run

主要包含3个部分：bridge_init_ofproto, bridge_run__, bridge_reconfigure.

bridge_init_ofproto

主要进行ofproto_dpif_class的注册，该类是structofproto_class的具体实现.

ofproto_init(const struct shash *iface_hints)
{
…
ofproto_class_register(&ofproto_dpif_class);
…
}

bridge_run__
主要包括2个部分：ofproto_type_run, ofproto_run.

ofproto_type_run /*Let each datapath type do the work that it needs to do. */

dpif_poll_threads_set与dpif_run最终都会走入pmd_thread_main流程.

dpif_recv_set以及udpif_set_threads主要处理netlink流程，使用ovs+dpdk的netdev流程不涉及.

type_run(const char *type)
{
struct dpif_backer *backer;

/*根据datapath type查找backer,即相同的datapath type只有一个backer*/
backer = shash_find_data(&all_dpif_backers, type);

...

/*dpif创建自己的 I/O polling threads,更新polling threads为dpif_run做准备
由dpif_netdev_class实现*/
dpif_poll_threads_set(backer->dpif, pmd_cpu_mask);

if (dpif_run(backer->dpif)) {
backer->need_revalidate = REV_RECONFIGURE;
}

udpif_run(backer->udpif);

...

return 0;
}

ofproto_run /* Let each bridge do the work that it needs to do. */

run将调用一系列与ofproto_dpif相关的run，包括：netflow_run, dpif_sflow_run, dpif_ipfix_run, port_run, bundle_run, stp_run, rstp_run, mac_learning_run, mcast_snooping_run...

process_port_change处理port的增删以及port属性的改变.

connmgr_run为每条在openflow连接上的消息调用‘handle_openflow’对消息进行处理，并将openflow连接本身以及消息继续传递.

ofproto_run(struct ofproto *p)
{
int error;
uint64_t new_seq;

error = p->ofproto_class->run(p);

...

if (p->ofproto_class->port_poll) {
char *devname;

while ((error = p->ofproto_class->port_poll(p, &devname)) != EAGAIN) {
process_port_change(p, error, devname);
}
}

...

connmgr_run(p->connmgr, handle_openflow);

return error;
}

bridge_reconfigure逐层完成桥配置的更新，首先通过ovs_cfg与当前全局变了all_bridges配置的对比完成对bridge层的更新，然后对ofproto层进行更新，最后通过调用bridge_run__->type_run完成对ofproto_dpif层的更新

bridge_reconfigure(const struct ovsrec_open_vswitch *ovs_cfg)
{
struct sockaddr_in *managers;
struct bridge *br, *next;
int sflow_bridge_number;
size_t n_managers;

...

/* Destroy "struct bridge"s, "struct port"s, and "struct iface"s according
* to 'ovs_cfg', with only very minimal configuration otherwise.
*
* This is mostly an update to bridge data structures. Nothing is pushed
* down to ofproto or lower layers. */
/*首先将cfg中的所有br_cfg添加到new_br中,
*br是全局变量all_bridges中的node
*根据br->name在new_br中查找br->cfg,若找不到或者br->type改变，删除这些br
*根据br_cfg->name在all_bridges中查找br,若没有那么将br_cfg添加至all_bridges*/
add_del_bridges(ovs_cfg);
HMAP_FOR_EACH (br, node, &all_bridges) {
/*wanted_ports包括ovsrec_bridge->cfg->ports[i]中的所有ports以及local port*/
bridge_collect_wanted_ports(br, &br->wanted_ports);
/*处理ports以及interfaces，逻辑与处理bridge类似*/
bridge_del_ports(br, &br->wanted_ports);
}

/* Start pushing configuration changes down to the ofproto layer:
*
*   - Delete ofprotos that are no longer configured.
*
*   - Delete ports that are no longer configured.
*
*   - Reconfigure existing ports to their desired configurations, or
*     delete them if not possible.
*
* We have to do all the deletions before we can do any additions, because
* the ports to be added might require resources that will be freed up by
* deletions (they might especially overlap in name). */
bridge_delete_ofprotos();
HMAP_FOR_EACH (br, node, &all_bridges) {
if (br->ofproto) {
bridge_delete_or_reconfigure_ports(br);
}
}

/* Finish pushing configuration changes to the ofproto layer:
*
*     - Create ofprotos that are missing.
*
*     - Add ports that are missing. */
HMAP_FOR_EACH_SAFE (br, next, node, &all_bridges) {
if (!br->ofproto) {
int error;

error = ofproto_create(br->name, br->type, &br->ofproto);
if (error) {
VLOG_ERR("failed to create bridge %s: %s", br->name,
ovs_strerror(error));
shash_destroy(&br->wanted_ports);
bridge_destroy(br, true);
} else {
/* Trigger storing datapath version. */
seq_change(connectivity_seq_get());
}
}
}
HMAP_FOR_EACH (br, node, &all_bridges) {
bridge_add_ports(br, &br->wanted_ports);
shash_destroy(&br->wanted_ports);
}

reconfigure_system_stats(ovs_cfg);

/* Complete the configuration. */
sflow_bridge_number = 0;
collect_in_band_managers(ovs_cfg, &managers, &n_managers);
HMAP_FOR_EACH (br, node, &all_bridges) {
struct port *port;

/* We need the datapath ID early to allow LACP ports to use it as the
* default system ID. */
bridge_configure_datapath_id(br);

HMAP_FOR_EACH (port, hmap_node, &br->ports) {
struct iface *iface;

port_configure(port);

LIST_FOR_EACH (iface, port_elem, &port->ifaces) {
iface_set_ofport(iface->cfg, iface->ofp_port);
/* Clear eventual previous errors */
ovsrec_interface_set_error(iface->cfg, NULL);
iface_configure_cfm(iface);
iface_configure_qos(iface, port->cfg->qos);
iface_set_mac(br, port, iface);
ofproto_port_set_bfd(br->ofproto, iface->ofp_port,
&iface->cfg->bfd);
ofproto_port_set_lldp(br->ofproto, iface->ofp_port,
&iface->cfg->lldp);
ofproto_port_set_config(br->ofproto, iface->ofp_port,
&iface->cfg->other_config);
}
}
bridge_configure_mirrors(br);
bridge_configure_forward_bpdu(br);
bridge_configure_mac_table(br);
bridge_configure_mcast_snooping(br);
bridge_configure_remotes(br, managers, n_managers);
bridge_configure_netflow(br);
bridge_configure_sflow(br, &sflow_bridge_number);
bridge_configure_ipfix(br);
bridge_configure_spanning_tree(br);
bridge_configure_tables(br);
bridge_configure_dp_desc(br);
bridge_configure_aa(br);
}
free(managers);

/* The ofproto-dpif provider does some final reconfiguration in its
* ->type_run() function.  We have to call it before notifying the database
* client that reconfiguration is complete, otherwise there is a very
* narrow race window in which e.g. ofproto/trace will not recognize the
* new configuration (sometimes this causes unit test failures). */
bridge_run__();
}