OpenvSwitch代码分析之bridge和port
ovs-vsctl add-br br0 会在数据库里面加入新bridge的信息
ovs-vsctl add-port br0 eth0 会在数据库里面加入新的port信息
void bridge_run(void)
{
//数据库发生变化
if (ovsdb_idl_get_seqno(idl) != idl_seqno || vlan_splinters_changed) {
idl_seqno = ovsdb_idl_get_seqno(idl);
bridge_reconfigure(cfg ? cfg : &null_cfg);
}
}
struct bridge {
struct hmap_node node; /* In 'all_bridges'. */
char *name; /* User-specified arbitrary name. */
char *type; /* Datapath type. */
uint8_t ea[ETH_ADDR_LEN]; /* Bridge Ethernet Address. */
uint8_t default_ea[ETH_ADDR_LEN]; /* Default MAC. */
const struct ovsrec_bridge *cfg;
/* OpenFlow switch processing. */
struct ofproto *ofproto; /* OpenFlow switch. */
/* Bridge ports. */
struct hmap ports; /* "struct port"s indexed by name. */
struct hmap ifaces; /* "struct iface"s indexed by ofp_port. */
}
ofproto代表一个bridge的open flow proto
struct ofproto {
struct hmap_node hmap_node; /* In global 'all_ofprotos' hmap. */
/*all the operation fcuntion of the ofproto*/
const struct ofproto_class *ofproto_class;
char *type; /* Datapath type. */
char *name;
uint64_t datapath_id; /* Datapath ID. */
struct oftable *tables; /*flow tables*/
int n_tables
struct hmap ports; /* Contains "struct ofport"s. */
/* OpenFlow connections. */
struct connmgr *connmgr;
}
struct ofproto_dpif {
struct hmap_node all_ofproto_dpifs_node; /* In 'all_ofproto_dpifs'. */
struct ofproto up;
struct dpif_backer *backer;/*每个ofproto都有相同的dpif_backer, 它代表整个ovs datapath*/
}
struct dpif_backer {
char *type;
int refcount;
struct dpif *dpif;
}
/*openvswitch datapath的handler, 负责与内核打交道*/
struct dpif {
const struct dpif_class *dpif_class;
}
bridge_reconfigure(const struct ovsrec_open_vswitch *ovs_cfg)
{
/*根据数据库更新信息添加或者删除bridge*/
add_del_bridges(ovs_cfg);
/*根据数据库更新信息为每个bridge收集新port或者删除port*/
HMAP_FOR_EACH (br, node, &all_bridges) {
/*如果是增加一个bridge,这里还会添加一个internal的local port为新的bridge*/
bridge_collect_wanted_ports(br, splinter_vlans, &br->wanted_ports);
bridge_del_ports(br, &br->wanted_ports);
}
HMAP_FOR_EACH_SAFE (br, next, node, &all_bridges) {
if (!br->ofproto) {
/*
如果是新加的brdige会分配一个ofproto,实际分配oproto_dpif
ofproto = ofproto_dpif_class->alloc
ofproto->ofproto_class = ofproto_dpif_class
会获取dpif_backer,如果还没有就通过dp_if_create_and_open函数使用OVS_DP_CMD_NEW创建一个ovs-datapath,生成ovs-system设备
从内核角度看，整个openvswitch系统就是一个datapath.
ofproto->ofproto_class->construct(ofproto)
*/
ofproto_create(br->name, br->type, &br->ofproto);
}
}
HMAP_FOR_EACH (br, node, &all_bridges) {
bridge_add_ports(br, &br->wanted_ports);
shash_destroy(&br->wanted_ports);
}
}
在内核看来用户态的bridge/datapath都只是整个openvswitch datapath的vport
只是新的bridge的vport是一个internal, add-port的是netdev, gre等
struct iface {
struct list port_elem; /* Element in struct port's "ifaces" list. */
struct hmap_node ofp_port_node; /* In struct bridge's "ifaces" hmap.
struct port *port; /* Containing port. */
struct netdev *netdev; /* Network device. */
ofp_port_t ofp_port; /* OpenFlow port number. */
const struct ovsrec_interface *cfg; /*cfg for interface*/
};
struct port {
struct bridge *bridge;
char *name;
struct hmap_node hmap_node; /* Element in struct bridge's "ports" hmap. */
const struct ovsrec_port *cfg /*cfg for port*/
/* An ordinary bridge port has 1 interface.
* A bridge port for bonding has at least 2 interfaces. */
struct list ifaces; /* List of "struct iface"s. */
};
bridge_add_ports--->iface_create
{
/*create interface*/
iface_do_create(br, iface_cfg, port_cfg, &ofp_port, &netdev);
iface->netdev = netdev;
hmap_insert(&br->ifaces, &iface->ofp_port_node, hash_ofp_port(ofp_port));
/*create port*/
port = port_create(br, port_cfg)
//hmap_insert(&br->ports, &port->hmap_node, hash_string(port->name, 0));
list_push_back(&port->ifaces, &iface->port_elem);
}
struct netdev {
/* The following do not change during the lifetime of a struct netdev. */
char *name; /* Name of network device. */
const struct netdev_class *netdev_class;
}
struct netdev_linux {
struct netdev up;
}
const struct netdev_class netdev_linux_class =
NETDEV_LINUX_CLASS(
"system",
netdev_linux_construct,
netdev_linux_get_stats,
NULL, /* set_stats */
netdev_linux_get_features,
netdev_linux_get_status);
const struct netdev_class netdev_internal_class =
NETDEV_LINUX_CLASS(
"internal",
netdev_linux_construct,
netdev_internal_get_stats,
netdev_internal_set_stats,
NULL, /* get_features */
netdev_internal_get_status);
}
/*gre*/
struct netdev_vport {
struct netdev up;
/* Tunnels. */
struct netdev_tunnel_config tnl_cfg;
};
TUNNEL_CLASS("gre", "gre_system"),
int iface_do_create()
{
/*根据type(internal, netdev, gre)获取interface 的netdev*/
netdev_open(iface_cfg->name, iface_get_type(iface_cfg, br->cfg), &netdev);
//netdev = rc->class->alloc()实际分配的是netdev_linux, gre是netdev_vport
//rc->class->construct(netdev);对于netdev这种设备要存在, internal和gre是后面创建的
/*设置interface options 只有gre设备才有*/
error = iface_set_netdev_config(iface_cfg, netdev);
ofproto_port_add(br->ofproto, netdev, ofp_portp);
/*获取ofport, 并且将ofport与dp_port做映射 ofport_install-->port_construct分配ofport*/
update_port(ofproto, netdev_name);
}
update_port
{
ofport_open(ofproto, &ofproto_port, &pp);
/*
//allocate the ofport
if (ofproto_port->ofp_port == OFPP_NONE) {
if (!strcmp(ofproto->name, ofproto_port->name)) {
ofproto_port->ofp_port = OFPP_LOCAL;
} else {
ofproto_port->ofp_port = alloc_ofp_port(ofproto,
ofproto_port->name);
}
}
*/
ofport_install(ofproto, netdev, &pp);
}
struct ofport {
struct hmap_node hmap_node; /* In struct ofproto's "ports" hmap. */
struct ofproto *ofproto; /* The ofproto that contains this port. */
struct netdev *netdev;
struct ofputil_phy_port pp;
ofp_port_t ofp_port; /* OpenFlow port number. */
};
struct ofport_dpif {
struct hmap_node odp_port_node; /* In dpif_backer's "odp_to_ofport_map". */
struct ofport up;
/*datapath port*/
odp_port_t odp_port;
}
ofport_install(struct ofproto *p, struct netdev *netdev, const struct ofputil_phy_port *pp)
{
/*实际分配ofport_dpif*/
ofport = p->ofproto_class->port_alloc();
ofport->ofproto = p;
ofport->netdev = netdev;
ofport->pp = *pp;
ofport->ofp_port = pp->port_no;
ofport->created = time_msec();
/* Add port to 'p'. */
hmap_insert(&p->ports, &ofport->hmap_node, hash_ofp_port(ofport->ofp_port));
/*map the ofport with dp_port*/
error = p->ofproto_class->port_construct(ofport);
}
ofproto_port_add--->ofproto->ofproto_class->port_add
port_add
{
/*netdev和internal都是获取的设备名, gre是获取的gre_system, 所以gre设备只会向add_port一次*/
dp_port_name = netdev_vport_get_dpif_port(netdev, namebuf, sizeof namebuf);
if (!dpif_port_exists(ofproto->backer->dpif, dp_port_name))
{
/*这里是port_no是openvswitch datapath的port no*/
dpif_port_add(ofproto->backer->dpif, netdev, &port_no)
//dpif->dpif_class->port_add(dpif, netdev, &port_no);
}
}
dpif_linux_port_add(struct dpif *dpif_, struct netdev *netdev,
odp_port_t *port_nop)
{
使用OVS_VPORT_CMD_NEW创建vport于内核中
}
///////////////////////////////////
内核态
int ovs_vport_cmd_new(struct sk_buff *skb, struct genl_info *info)
{
parms.name = nla_data(a[OVS_VPORT_ATTR_NAME]);
parms.type = nla_get_u32(a[OVS_VPORT_ATTR_TYPE]);
parms.options = a[OVS_VPORT_ATTR_OPTIONS];
parms.dp = dp;
parms.port_no = port_no;
parms.upcall_portid = nla_get_u32(a[OVS_VPORT_ATTR_UPCALL_PID]);
vport = new_vport(&parms);--->ovs_vport_add(parms);--->vport_ops->create
}
//normal netdev: eth0 veth0
const struct vport_ops ovs_netdev_vport_ops = {
.type = OVS_VPORT_TYPE_NETDEV,
.create = netdev_create,
.destroy = netdev_destroy,
.get_name = ovs_netdev_get_name,
.send = netdev_send,/*当报文的需要通过该vport发送的处理函数*/
};
struct vport *netdev_create(const struct vport_parms *parms)
{
vport = ovs_vport_alloc(sizeof(struct netdev_vport), &ovs_netdev_vport_ops, parms);
netdev_vport = netdev_vport_priv(vport);
/*find the real dev*/
netdev_vport->dev = dev_get_by_name(ovs_dp_get_net(vport->dp), parms->name);
/*设置ovs内核处理函数, 使netdev收到的报文不再走传统协议栈*/
netdev_rx_handler_register(netdev_vport->dev, netdev_frame_hook, vport)
}
static int netdev_send(struct vport *vport, struct sk_buff *skb)
{
struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
int mtu = netdev_vport->dev->mtu;
int len;
skb->dev = netdev_vport->dev;
len = skb->len;
/*直接从该dev发送*/
dev_queue_xmit(skb);
}
//internal: bridge port
const struct vport_ops ovs_internal_vport_ops = {
.type = OVS_VPORT_TYPE_INTERNAL,
.create = internal_dev_create,
.destroy = internal_dev_destroy,
.get_name = ovs_netdev_get_name,
.send = internal_dev_recv,
};
truct net_device_ops internal_dev_netdev_ops = {
.ndo_start_xmit = internal_dev_xmit,
};
/*internal net device发送函数就是ovs的处理函数*/
static int internal_dev_xmit(struct sk_buff *skb, struct net_device *netdev)
{
ovs_vport_receive(internal_dev_priv(netdev)->vport, skb, NULL);
}
struct vport *internal_dev_create(const struct vport_parms *parms)
{
vport = ovs_vport_alloc(sizeof(struct netdev_vport), &ovs_internal_vport_ops, parms);
netdev_vport = netdev_vport_priv(vport);
/*创建一个ethernet device, netdev->netdev_ops = &internal_dev_netdev_ops;*/
netdev_vport->dev = alloc_netdev(sizeof(struct internal_dev), parms->name, do_setup)
internal_dev = internal_dev_priv(netdev_vport->dev);
internal_dev->vport = vport;
err = register_netdevice(netdev_vport->dev);
}
/*如果报文指定从internal设备发出, 数据包会重新注入协议栈*/
int internal_dev_recv(struct vport *vport, struct sk_buff *skb)
{
skb->dev = netdev;
skb->pkt_type = PACKET_HOST;
skb->protocol = eth_type_trans(skb, netdev);
skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
netif_rx(skb);
}
//gre port
const struct vport_ops ovs_gre_vport_ops = {
.type = OVS_VPORT_TYPE_GRE,
.create = gre_create,
.destroy = gre_tnl_destroy,
.get_name = gre_get_name,
.send = gre_send,
};
整个系统只创建一个gre device在内核
struct vport *gre_create(const struct vport_parms *parms)
{
ovs_net = net_generic(net, ovs_net_id);
if (ovsl_dereference(ovs_net->vport_net.gre_vport)) {
vport = ERR_PTR(-EEXIST);
goto error;
}
vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms);
}
发送
报文通过gre口发送会根据下发具体action规则添加gre header以及deliver header
int gre_send(struct vport *vport, struct sk_buff *skb)
接收
当系统收到gre报文,去掉了deliver header获取gre header信息传递给gre_rcv，然后进入ovs处理函数进行处理
