ovs-vswitchd.c的main函数最终会进入一个while循环,在这个无限循环中,里面最重要的两个函数是bridge_run()和netdev_run()。
Openvswitch主要管理两种类型的设备,一个是创建的虚拟网桥,一个是连接到虚拟网桥上的设备。
其中bridge_run就是初始化数据库中已经创建的虚拟网桥。
一、虚拟网桥的初始化bridge_run
bridge_run会调用bridge_run__,bridge_run__中最重要的是对于所有的网桥,都调用ofproto_run
- static void
- bridge_run__(void)
- {
- ……
- /* Let each bridge do the work that it needs to do. */
- HMAP_FOR_EACH (br, node, &all_bridges) {
- ofproto_run(br->ofproto);
- }
- }
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Int ofproto_run(struct ofproto *p)会调用error = p->ofproto_class->run(p);
ofproto_class的定义在ofproto-provider.h中,它的实现定义在ofproto-dpif.c中,这里面的所有的函数,在这个文件中都有定义。
- const struct ofproto_class ofproto_dpif_class = {
- init,
- enumerate_types,
- enumerate_names,
- del,
- port_open_type,
- type_run,
- type_wait,
- alloc,
- construct,
- destruct,
- dealloc,
- run,
- wait,
- NULL, /* get_memory_usage. */
- type_get_memory_usage,
- flush,
- query_tables,
- set_tables_version,
- port_alloc,
- port_construct,
- port_destruct,
- port_dealloc,
- port_modified,
- port_reconfigured,
- port_query_by_name,
- port_add,
- port_del,
- port_get_stats,
- port_dump_start,
- port_dump_next,
- port_dump_done,
- port_poll,
- port_poll_wait,
- port_is_lacp_current,
- port_get_lacp_stats,
- NULL, /* rule_choose_table */
- rule_alloc,
- rule_construct,
- rule_insert,
- rule_delete,
- rule_destruct,
- rule_dealloc,
- rule_get_stats,
- rule_execute,
- set_frag_handling,
- packet_out,
- set_netflow,
- get_netflow_ids,
- set_sflow,
- set_ipfix,
- set_cfm,
- cfm_status_changed,
- get_cfm_status,
- set_lldp,
- get_lldp_status,
- set_aa,
- aa_mapping_set,
- aa_mapping_unset,
- aa_vlan_get_queued,
- aa_vlan_get_queue_size,
- set_bfd,
- bfd_status_changed,
- get_bfd_status,
- set_stp,
- get_stp_status,
- set_stp_port,
- get_stp_port_status,
- get_stp_port_stats,
- set_rstp,
- get_rstp_status,
- set_rstp_port,
- get_rstp_port_status,
- set_queues,
- bundle_set,
- bundle_remove,
- mirror_set__,
- mirror_get_stats__,
- set_flood_vlans,
- is_mirror_output_bundle,
- forward_bpdu_changed,
- set_mac_table_config,
- set_mcast_snooping,
- set_mcast_snooping_port,
- set_realdev,
- NULL, /* meter_get_features */
- NULL, /* meter_set */
- NULL, /* meter_get */
- NULL, /* meter_del */
- group_alloc, /* group_alloc */
- group_construct, /* group_construct */
- group_destruct, /* group_destruct */
- group_dealloc, /* group_dealloc */
- group_modify, /* group_modify */
- group_get_stats, /* group_get_stats */
- get_datapath_version, /* get_datapath_version */
- };
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在ofproto-provider.h中注释里是这样说的。
这里定义了四类数据结构
Struct ofproto表示一个交换机
Struct ofport表示交换机上的一个端口
Struct rule表示交换机上的一条flow规则
Struct ofgroup表示一个flow规则组
上面说到启动的过程中,会调用ofproto_class->run,也即会调用ofproto-dpif.c中的static int run(struct ofproto *ofproto_)函数。
在这个函数中,会初始化netflow, sflow, ipfix,stp, rstp, mac address learning等一系列操作。
bridge_run还会调用static void bridge_reconfigure(const struct ovsrec_open_vswitch *ovs_cfg),其中ovs_cfg是从ovsdb-server里面读取出来的配置。
在这个函数里面,对于每一个网桥,将网卡添加进去
- HMAP_FOR_EACH (br, node, &all_bridges) {
- bridge_add_ports(br, &br->wanted_ports);
- shash_destroy(&br->wanted_ports);
- }
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- static void
- bridge_add_ports(struct bridge *br, const struct shash *wanted_ports)
- {
- /* First add interfaces that request a particular port number. */
- bridge_add_ports__(br, wanted_ports, true);
-
- /* Then add interfaces that want automatic port number assignment.
- * We add these afterward to avoid accidentally taking a specifically
- * requested port number. */
- bridge_add_ports__(br, wanted_ports, false);
- }
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static void bridge_add_ports__(struct bridge *br, const struct shash *wanted_ports, bool with_requested_port)会调用
static bool iface_create(struct bridge *br, const struct ovsrec_interface *iface_cfg, const struct ovsrec_port *port_cfg)会调用
static int iface_do_create(const struct bridge *br, const struct ovsrec_interface *iface_cfg, const struct ovsrec_port *port_cfg, ofp_port_t *ofp_portp, struct netdev **netdevp, char **errp)会调用
int ofproto_port_add(struct ofproto *ofproto, struct netdev *netdev, ofp_port_t *ofp_portp)会调用
- error = ofproto->ofproto_class->port_add(ofproto, netdev);
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会调用ofproto-dpif.c中的ofproto_dpif_class的static int port_add(struct ofproto *ofproto_, struct netdev *netdev)函数。
会调用int dpif_port_add(struct dpif *dpif, struct netdev *netdev, odp_port_t *port_nop)会调用
- error = dpif->dpif_class->port_add(dpif, netdev, &port_no);
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会调用dpif_netlink_class的port_add函数,也即dpif_netlink_port_add,也即
static int dpif_netlink_port_add(struct dpif *dpif_, struct netdev *netdev,odp_port_t *port_nop)会调用
static int dpif_netlink_port_add__(struct dpif_netlink *dpif, struct netdev *netdev, odp_port_t *port_nop)
在这个函数里面,会调用netlink的API,命令为OVS_VPORT_CMD_NEW
- const char *name = netdev_vport_get_dpif_port(netdev,
- namebuf, sizeof namebuf);
- struct dpif_netlink_vport request, reply;
- struct nl_sock **socksp = NULL;
-
- if (dpif->handlers) {
- socksp = vport_create_socksp(dpif, &error);
- if (!socksp) {
- return error;
- }
- }
-
- dpif_netlink_vport_init(&request);
- request.cmd = OVS_VPORT_CMD_NEW;
- request.dp_ifindex = dpif->dp_ifindex;
- request.type = netdev_to_ovs_vport_type(netdev);
-
- request.name = name;
-
- upcall_pids = vport_socksp_to_pids(socksp, dpif->n_handlers);
- request.n_upcall_pids = socksp ? dpif->n_handlers : 1;
- request.upcall_pids = upcall_pids;
- error = dpif_netlink_vport_transact(&request, &reply, &buf);
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这里会调用内核模块openvswitch.ko,在内核中添加虚拟网卡。这部分详细的过程将在下一节分析。
二、虚拟网卡的初始化netdev_run()
- void
- netdev_run(void)
- OVS_EXCLUDED(netdev_class_mutex, netdev_mutex)
- {
- struct netdev_registered_class *rc;
-
- netdev_initialize();
- ovs_mutex_lock(&netdev_class_mutex);
- HMAP_FOR_EACH (rc, hmap_node, &netdev_classes) {
- if (rc->class->run) {
- rc->class->run();
- }
- }
- ovs_mutex_unlock(&netdev_class_mutex);
- }
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依次循环调用netdev_classes中的每一个run。
对于不同类型的虚拟网卡,都有对应的netdev_class。
例如对于dpdk的网卡有
- static const struct netdev_class dpdk_class =
- NETDEV_DPDK_CLASS(
- "dpdk",
- NULL,
- netdev_dpdk_construct,
- netdev_dpdk_destruct,
- netdev_dpdk_set_multiq,
- netdev_dpdk_eth_send,
- netdev_dpdk_get_carrier,
- netdev_dpdk_get_stats,
- netdev_dpdk_get_features,
- netdev_dpdk_get_status,
- netdev_dpdk_rxq_recv);
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对于物理网卡,也需要有相应的netdev_class
- const struct netdev_class netdev_linux_class =
- NETDEV_LINUX_CLASS(
- "system",
- netdev_linux_construct,
- netdev_linux_get_stats,
- netdev_linux_get_features,
- netdev_linux_get_status);
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对于连接到KVM的tap网卡
- const struct netdev_class netdev_tap_class =
- NETDEV_LINUX_CLASS(
- "tap",
- netdev_linux_construct_tap,
- netdev_tap_get_stats,
- netdev_linux_get_features,
- netdev_linux_get_status);
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对于虚拟的软网卡,比如veth pair
- const struct netdev_class netdev_internal_class =
- NETDEV_LINUX_CLASS(
- "internal",
- netdev_linux_construct,
- netdev_internal_get_stats,
- NULL, /* get_features */
- netdev_internal_get_status);
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其中NETDEV_LINUX_CLASS是一个宏,不是所有的参数都需要全部填写。
- #define NETDEV_LINUX_CLASS(NAME, CONSTRUCT, GET_STATS, \
- GET_FEATURES, GET_STATUS) \
- { \
- NAME, \
- \
- NULL, \
- netdev_linux_run, \
- netdev_linux_wait, \
- \
- netdev_linux_alloc, \
- CONSTRUCT, \
- netdev_linux_destruct, \
- netdev_linux_dealloc, \
- NULL, /* get_config */ \
- NULL, /* set_config */ \
- NULL, /* get_tunnel_config */ \
- NULL, /* build header */ \
- NULL, /* push header */ \
- NULL, /* pop header */ \
- NULL, /* get_numa_id */ \
- NULL, /* set_multiq */ \
- \
- netdev_linux_send, \
- netdev_linux_send_wait, \
- \
- netdev_linux_set_etheraddr, \
- netdev_linux_get_etheraddr, \
- netdev_linux_get_mtu, \
- netdev_linux_set_mtu, \
- netdev_linux_get_ifindex, \
- netdev_linux_get_carrier, \
- netdev_linux_get_carrier_resets, \
- netdev_linux_set_miimon_interval, \
- GET_STATS, \
- \
- GET_FEATURES, \
- netdev_linux_set_advertisements, \
- \
- netdev_linux_set_policing, \
- netdev_linux_get_qos_types, \
- netdev_linux_get_qos_capabilities, \
- netdev_linux_get_qos, \
- netdev_linux_set_qos, \
- netdev_linux_get_queue, \
- netdev_linux_set_queue, \
- netdev_linux_delete_queue, \
- netdev_linux_get_queue_stats, \
- netdev_linux_queue_dump_start, \
- netdev_linux_queue_dump_next, \
- netdev_linux_queue_dump_done, \
- netdev_linux_dump_queue_stats, \
- \
- netdev_linux_get_in4, \
- netdev_linux_set_in4, \
- netdev_linux_get_in6, \
- netdev_linux_add_router, \
- netdev_linux_get_next_hop, \
- GET_STATUS, \
- netdev_linux_arp_lookup, \
- \
- netdev_linux_update_flags, \
- \
- netdev_linux_rxq_alloc, \
- netdev_linux_rxq_construct, \
- netdev_linux_rxq_destruct, \
- netdev_linux_rxq_dealloc, \
- netdev_linux_rxq_recv, \
- netdev_linux_rxq_wait, \
- netdev_linux_rxq_drain, \
- }
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rc->class->run()调用的是netdev-linux.c下的netdev_linux_run
netdev_linux_run会调用netlink的sock得到虚拟网卡的状态,并且更新状态。
- error = nl_sock_recv(sock, &buf, false);
- if (!error) {
- struct rtnetlink_change change;
- if (rtnetlink_parse(&buf, &change)) {
- struct netdev *netdev_ = netdev_from_name(change.ifname);
- if (netdev_ && is_netdev_linux_class(netdev_->netdev_class)) {
- struct netdev_linux *netdev = netdev_linux_cast(netdev_);
- ovs_mutex_lock(&netdev->mutex);
- netdev_linux_update(netdev, &change);
- ovs_mutex_unlock(&netdev->mutex);
- }
- netdev_close(netdev_);
- }
- }
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