1)hello
控制器6633端口（最高支持OpenFlow 1.0）-->交换机50822端口
交换机50822端口（最高支持OpenFlow 1.5）-->控制器6633端口
2）Feature Request
控制器6633端口（需要你的特征信息）-->交换机50836端口
3)set conig
控制器52298端口（请按照我给你的flag和max bytes of packet进行配置）-->控制器52298端口
3）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
4）Features Reply
5)Packet_in
有两种情况：
·交换机查找流表，发现没有匹配条目时
·有匹配条目但是对应的action口是OUTPUT=CONTROLLER时
交换机50882端口（有数据包进来，请指示）-->控制器6633端口
6)Flow_mod
分析抓取的flow_mod数据包，控制器通过6633端口向交换机50822端口，交换机50836端口下发流表项，指导数据的转发处理
7)Packet_out
控制器6633端口（请按照我给你的action进行处理）-->交换机552298duankou
·查看抓包结果，分析OpenFlow协议中交换机与控制器的消息交互过程，画出相关交互图或流程图
·回答问题：交换机与控制器建立通信时是使用TCP协议还是UDP协议？
TCP
答：是TCP协议
3.进阶要求为选做，有完成的同学请提交相关截图对应的OpenFlow代码，加以注释说明，有完成比未完成的上机分数更高。
1）Hello
点击查看代码
/* 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
点击查看代码
/* 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
点击查看代码
/* 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. */
};
4)Port Staus
点击查看代码
/* 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);
点击查看代码
/* 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. */
};
6)Packet_in
点击查看代码
·交换机查找流表，没有匹配条目
/* Why is this packet being sent to the controller? */
enum ofp_packet_in_reason {
OFPR_NO_MATCH, /* No matching flow. */
OFPR_ACTION /* Action explicitly output to controller. */
};
·交换机查找流表，有匹配条目，对应action是OUTPUT=CONTROLLER，固定收到向控制器发送包
/* 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. */
};
点击查看代码
/* 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. */
};
点击查看代码
/* 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);
个人总结：本次实验的难易程度适中，主要是运用抓包软件Wireshark来进一步增强对构建拓扑以及控制器之间是怎么交互运行的，对 OpenFlow 协议数据交互过程进行抓包和wireshark的一些基础功能的运用，通过本次实验对SDN学习的内容的方向有了一定的了解，和SDN对交换机的优化和实现有了基础的认识。通过本次实验，我对抓包软件Wireshark更加的了解以及可以熟练掌握，对openflow协议数据交互过程有了进一步的了解和认识，对SDN也有了一些了解，同时也可以借助工具对OpenFlow协议数据交互过程进行分析，同时需要注意的店的点是，需要先打开抓包软件Wireshark，再进行建立拓扑
标签：struct,OpenFlow,实践,uint32,header,ofp,uint16,实验,port From： https://www.cnblogs.com/ririgriffin/p/16750814.html