基础要求:
1.hello
控制器6633端口（我最高能支持OpenFlow 1.0） ---> 交换机47646端口
交换机47646端口（我最高能支持OpenFlow 1.0） ---> 控制器6633端口
于是双方建立连接，并使用OpenFlow 1.0
2.Features Request
控制器6633端口（我需要你的特征信息） ---> 交换机47646端口
3.Set_Conig
控制器6633端口（请按照我给你的flag和max bytes of packet进行配置） ---> 交换机47646端口
4.Port_Status
当交换机端口发生变化时，告知控制器相应的端口状态。
5.Features Reply
交换机47646端口（这是我的特征信息，请查收） ---> 控制器6633端口
6.Packet_in
交换机47646端口（有数据包进来，请指示）--- 控制器6633端口
7.Flow_mod
控制器通过6633端口向交换机47646端口、交换机47646端口下发流表项，指导数据的转发处理
8.Packet_out
控制器6633端口向交换机47648端口发送数据，并告知交换机输出到65531端口。
进阶要求:
1、hello
/* Header on all OpenFlow packets. /
struct ofp_header {
uint8_t version; / OFP_VERSION. /
uint8_t type; / One of the OFPT_ constants. /
uint16_t length; / Length including this ofp_header. /
uint32_t xid; / Transaction id associated with this packet.
Replies use the same id as was in the request
to facilitate pairing. */
};
OFP_ASSERT(sizeof(struct ofp_header) == 8);
/* OFPT_HELLO. This message has an empty body, but implementations must
- ignore any data included in the body, to allow for future extensions. */
struct ofp_hello {
struct ofp_header header;
};
2、Features Request
/* Header on all OpenFlow packets. /
struct ofp_header {
uint8_t version; / OFP_VERSION. /
uint8_t type; / One of the OFPT_ constants. /
uint16_t length; / Length including this ofp_header. /
uint32_t xid; / Transaction id associated with this packet.
Replies use the same id as was in the request
to facilitate pairing. */
};
OFP_ASSERT(sizeof(struct ofp_header) == 8);
/* OFPT_HELLO. This message has an empty body, but implementations must
- ignore any data included in the body, to allow for future extensions. */
struct ofp_hello {
struct ofp_header header;
};
3、Set Conig
/* Switch configuration. /
struct ofp_switch_config {
struct ofp_header header;
uint16_t flags; / OFPC_* flags. /
uint16_t miss_send_len; / Max bytes of new flow that datapath should
send to the controller. */
};
OFP_ASSERT(sizeof(struct ofp_switch_config) == 12);
4、Port_Status
/* A physical port has changed in the datapath /
struct ofp_port_status {
struct ofp_header header;
uint8_t reason; / One of OFPPR_*. /
uint8_t pad[7]; / Align to 64-bits. */
struct ofp_phy_port desc;
};
OFP_ASSERT(sizeof(struct ofp_port_status) == 64);
5、Features Reply
/* Description of a physical port /
struct ofp_phy_port {
uint16_t port_no;
uint8_t hw_addr[OFP_ETH_ALEN];
char name[OFP_MAX_PORT_NAME_LEN]; / Null-terminated */
uint32_t config; /* Bitmap of OFPPC_* flags. */
uint32_t state; /* Bitmap of OFPPS_* flags. */
/* Bitmaps of OFPPF_* that describe features. All bits zeroed if
* unsupported or unavailable. */
uint32_t curr; /* Current features. */
uint32_t advertised; /* Features being advertised by the port. */
uint32_t supported; /* Features supported by the port. */
uint32_t peer; /* Features advertised by peer. */
};
OFP_ASSERT(sizeof(struct ofp_phy_port) == 48);
/* Switch features. /
struct ofp_switch_features {
struct ofp_header header;
uint64_t datapath_id; / Datapath unique ID. The lower 48-bits are for
a MAC address, while the upper 16-bits are
implementer-defined. */
uint32_t n_buffers; /* Max packets buffered at once. */
uint8_t n_tables; /* Number of tables supported by datapath. */
uint8_t pad[3]; /* Align to 64-bits. */
/* Features. */
uint32_t capabilities; /* Bitmap of support "ofp_capabilities". */
uint32_t actions; /* Bitmap of supported "ofp_action_type"s. */
/* Port info.*/
struct ofp_phy_port ports[0]; /* Port definitions. The number of ports
is inferred from the length field in
the header. */
};
OFP_ASSERT(sizeof(struct ofp_switch_features) == 32);
6、Packet_in
/* Packet received on port (datapath -> controller). /
struct ofp_packet_in {
struct ofp_header header;
uint32_t buffer_id; / ID assigned by datapath. /
uint16_t total_len; / Full length of frame. /
uint16_t in_port; / Port on which frame was received. /
uint8_t reason; / Reason packet is being sent (one of OFPR_*) /
uint8_t pad;
uint8_t data[0]; / Ethernet frame, halfway through 32-bit word,
so the IP header is 32-bit aligned. The
amount of data is inferred from the length
field in the header. Because of padding,
offsetof(struct ofp_packet_in, data) ==
sizeof(struct ofp_packet_in) - 2. */
};
OFP_ASSERT(sizeof(struct ofp_packet_in) == 20);
7、Flow_mod
/* Flow setup and teardown (controller -> datapath). /
struct ofp_flow_mod {
struct ofp_header header;
struct ofp_match match; / Fields to match /
uint64_t cookie; / Opaque controller-issued identifier. */
/* Flow actions. */
uint16_t command; /* One of OFPFC_*. */
uint16_t idle_timeout; /* Idle time before discarding (seconds). */
uint16_t hard_timeout; /* Max time before discarding (seconds). */
uint16_t priority; /* Priority level of flow entry. */
uint32_t buffer_id; /* Buffered packet to apply to (or -1).
Not meaningful for OFPFC_DELETE*. */
uint16_t out_port; /* For OFPFC_DELETE* commands, require
matching entries to include this as an
output port. A value of OFPP_NONE
indicates no restriction. */
uint16_t flags; /* One of OFPFF_*. */
struct ofp_action_header actions[0]; /* The action length is inferred
from the length field in the
header. */
};
OFP_ASSERT(sizeof(struct ofp_flow_mod) == 72);
8、Packet_out
/* Send packet (controller -> datapath). /
struct ofp_packet_out {
struct ofp_header header;
uint32_t buffer_id; / ID assigned by datapath (-1 if none). /
uint16_t in_port; / Packet's input port (OFPP_NONE if none). /
uint16_t actions_len; / Size of action array in bytes. /
struct ofp_action_header actions[0]; / Actions. /
/ uint8_t data[0]; / / Packet data. The length is inferred
from the length field in the header.
(Only meaningful if buffer_id == -1.) */
};
OFP_ASSERT(sizeof(struct ofp_packet_out) == 16);
个人感想:本次实验比较简单，没有什么高难度操作，主要是抓包分析OpenFlow通讯过程数据包的的流动。对wireshark工具使用更加熟练，通过抓包的结果进行观察与学习，了解OpenFlow主要消息类型对应的数据结构定义。
遇到的问题：先运行拓扑再抓包发现没有抓到包.先开启抓包再运行拓扑即可解决