【sdn】openflow1.3学习笔记（二）

OpenFlow 系列文章链接归类：

【sdn】openflow1.3学习笔记（一）

前言

   在这篇文章里我们了解一下openflow1.3的全部特性

五、OpenFlow channel

   openflow channel 是openflow-switch和controller之间的一套接口，通过这套接口，controller能够下发配置给openflow-switch，接受从openflow-switch报告回来的事件，以及下发packet-out消息。

   openflow channel 支持三种类型的消息：

• 控制器发往switch（controller-to-switch）：由控制器发起，用于控制器直接管理或配置交换机。
• 异步（asynchronous）：由交换机发起，向控制器上报事件或者交换机的变化。
• 同步（symmetric）：控制器、交换机 双方均可发起，

controller-to-switch

controller-to-switch 模式的消息：

• feature：发送给交换机关于开启特性功能的请求，交换机会给控制器response，feature消息常常发生在创建openflow channel时。
• configuration： 控制器可以查询或者设定交换机配置，交换机会回复查询消息。
• modify-state：增删改流表内的 flow / group 或者设定switch port配置
• read-state：读取交换机内的不同信息，诸如：当前配置，统计数据，功能。
• packet-out：转发通过packet-in接收到的包，packet-out消息要么包含整个packet的内容，要么指定buffer-id标记包，packet-out消息中必须包含action，空的action会被drop。
• barrier：用于确保消息依赖关系已经满足或接收操作完成的通知。
• role-request： 用于控制器去设定openflow channel的角色，常用于一台交换机连接了多个控制器
• asynchronous-configuration： 希望在OpenFlow通道上接收的异步消息上设置一个额外的过滤器，或者查询该过滤器，常用于一台交换机连接了多个控制器，在建立openflow channel时下发。

Asynchronize

Asynchronize模式的消息：

• Packet-in： 将当前的pkt发送给控制器，如果交换机有能力缓存报文且有足够内存缓存，可以使用buffer-id来标记该报文，此时，只需将buffer-id和部分pkt header传给控制器即可，减少了上报报文的大小，当控制器下发packet-out消息时，指定buffer-id为之前的ID，即可在交换机中找到之前缓存的报文，进行下一步转发。缓存的数据包缓存一定时间后会做过期处理drop掉。不支持缓存报文或者内存大小不足的交换机，只能将完整报文发送给控制器进行处理。
• flow-removed： 通知控制器 流表里删除了一条流，该msg里会带上 OFPFF_SEND_FLOW_REM 标记位，以及删除结果或者流过期结果。
• port-status： 通知控制器关于port的配置或者状态变化，比如port被用户手动down掉，或者port自身出问题down掉
• error： 向控制器通知一些error信息。

Symmetric

Symmetric模式的消息：

• Hello：交换机和控制器之间在连接启动时交换Hello消息
• Echo： Echo request/reply消息可以从交换机或控制器发送，且必须返回一个Echo reply。它们主要用于验证控制器-交换机连接的有效性，也可以用于测量其延迟或带宽。
• Experimenter：这是一个用于未来OpenFlow修订的特性的暂存区。

多控制器模式

多控制器的角色：

• OFPCR_ROLE_EQUAL：每个控制器都有操控交换机的全部权限，每个控制器都会接收到所有的交换机异步消息，交换机无需进行控制器的资源仲裁或平衡。
• OFPCR_ROLE_SLAVE：控制器只有只读权限，异步消息通常只会接收到port-status，当slave角色下发改变switch状态的controller-to-switch消息时（OFPT_PACKET_OUT, OFPT_FLOW_MOD, OFPT_GROUP_MOD, OFPT_PORT_MOD, OFPT_TABLE_MOD），会接到OFPT_ERROR。
• OFPCR_ROLE_MASTER：成为master的控制器拥有全部权限，一个switch只允许有一台master，成为master之后会将除了本身其他所有的控制器变为slave。

多控制器场景下，controller可以设定不同的controller接受特定的消息，这样就可以在master上屏蔽某些不想监听的消息，卸载到从控制器上进行监听。

辅助连接

   默认情况下，OpenFlow交换机和OpenFlow控制器之间的OpenFlow通道是一个单一的网络连接。OpenFlow通道也可以由一个主连接和多个辅助连接组成。辅助连接由OpenFlow交换机创建，有助于提高交换机处理性能并利用大多数交换机实现的并行性。
  辅助连接用datapath ID 和 auxiliary ID 进行一个唯一标识，主链接 auxiliary ID 为0，辅助连接必须使用与主连接相同的源IP，目的IP可以在交换机上配置与主连接不同
  只有在相应的主连接是活的时候，它才必须与控制器建立和保持辅助连接。辅助连接的连接设置与主连接相同。如果交换机检测到与某个控制器的主连接断开，它必须立即关闭与该控制器的所有辅助连接，使控制器能够正确解决Datapath ID冲突。

openflow 的一些结构体

/* 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 requestto facilitate pairing. */
};
OFP_ASSERT(sizeof(struct ofp_header) == 8);

enum ofp_type {/* Immutable messages. */OFPT_HELLO = 0, /* Symmetric message */OFPT_ERROR = 1, /* Symmetric message */OFPT_ECHO_REQUEST = 2, /* Symmetric message */OFPT_ECHO_REPLY = 3, /* Symmetric message */OFPT_EXPERIMENTER = 4, /* Symmetric message *//* Switch configuration messages. */OFPT_FEATURES_REQUEST = 5, /* Controller/switch message */OFPT_FEATURES_REPLY = 6, /* Controller/switch message */OFPT_GET_CONFIG_REQUEST = 7, /* Controller/switch message */OFPT_GET_CONFIG_REPLY = 8, /* Controller/switch message */OFPT_SET_CONFIG = 9, /* Controller/switch message *//* Asynchronous messages. */OFPT_PACKET_IN = 10, /* Async message */OFPT_FLOW_REMOVED = 11, /* Async message */OFPT_PORT_STATUS = 12, /* Async message *//* Controller command messages. */OFPT_PACKET_OUT = 13, /* Controller/switch message */OFPT_FLOW_MOD = 14, /* Controller/switch message */OFPT_GROUP_MOD = 15, /* Controller/switch message */OFPT_PORT_MOD = 16, /* Controller/switch message */OFPT_TABLE_MOD = 17, /* Controller/switch message *//* Multipart messages. */OFPT_MULTIPART_REQUEST = 18, /* Controller/switch message */OFPT_MULTIPART_REPLY = 19, /* Controller/switch message *//* Barrier messages. */OFPT_BARRIER_REQUEST = 20, /* Controller/switch message */OFPT_BARRIER_REPLY = 21, /* Controller/switch message *//* Queue Configuration messages. */OFPT_QUEUE_GET_CONFIG_REQUEST = 22, /* Controller/switch message */OFPT_QUEUE_GET_CONFIG_REPLY = 23, /* Controller/switch message *//* Controller role change request messages. */OFPT_ROLE_REQUEST = 24, /* Controller/switch message */OFPT_ROLE_REPLY = 25, /* Controller/switch message *//* Asynchronous message configuration. */OFPT_GET_ASYNC_REQUEST = 26, /* Controller/switch message */OFPT_GET_ASYNC_REPLY = 27, /* Controller/switch message */OFPT_SET_ASYNC = 28, /* Controller/switch message *//* Meters and rate limiters configuration messages. */OFPT_METER_MOD = 29, /* Controller/switch message */
};

/* Description of a port */
struct ofp_port {uint32_t port_no;uint8_t pad[4];uint8_t hw_addr[OFP_ETH_ALEN];uint8_t pad2[2]; /* Align to 64 bits. */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. */uint32_t curr_speed; /* Current port bitrate in kbps. */uint32_t max_speed; /* Max port bitrate in kbps */
};
OFP_ASSERT(sizeof(struct ofp_port) == 64);

/* Full description for a queue. */
struct ofp_packet_queue {uint32_t queue_id; /* id for the specific queue. */uint32_t port; /* Port this queue is attached to. */uint16_t len; /* Length in bytes of this queue desc. */uint8_t pad[6]; /* 64-bit alignment. */struct ofp_queue_prop_header properties[0]; /* List of properties. */
};

OpenFlow交换机通过简单的排队机制实现QoS

/* Common description for a queue. */
struct ofp_queue_prop_header {uint16_t property; /* One of OFPQT_. */uint16_t len; /* Length of property, including this header. */uint8_t pad[4]; /* 64-bit alignemnt. */
};
OFP_ASSERT(sizeof(struct ofp_queue_prop_header) == 8);

/* Min-Rate queue property description. */
struct ofp_queue_prop_min_rate {struct ofp_queue_prop_header prop_header; /* prop: OFPQT_MIN, len: 16. */uint16_t rate; /* In 1/10 of a percent; >1000 -> disabled. */uint8_t pad[6]; /* 64-bit alignment */
};
OFP_ASSERT(sizeof(struct ofp_queue_prop_min_rate) == 16);

/* Max-Rate queue property description. */
struct ofp_queue_prop_max_rate {struct ofp_queue_prop_header prop_header; /* prop: OFPQT_MAX, len: 16. */uint16_t rate; /* In 1/10 of a percent; >1000 -> disabled. */uint8_t pad[6]; /* 64-bit alignment */
};
OFP_ASSERT(sizeof(struct ofp_queue_prop_max_rate) == 16);

/* Experimenter queue property description. */
struct ofp_queue_prop_experimenter {struct ofp_queue_prop_header prop_header; /* prop: OFPQT_EXPERIMENTER, len: 16. */uint32_t experimenter; /* Experimenter ID which takes the sameform as in structofp_experimenter_header. */uint8_t pad[4]; /* 64-bit alignment */uint8_t data[0]; /* Experimenter defined data. */
};
OFP_ASSERT(sizeof(struct ofp_queue_prop_experimenter) == 16);

流匹配：

/* Fields to match against flows */
struct ofp_match {uint16_t type; /* One of OFPMT_* */uint16_t length; /* Length of ofp_match (excluding padding) *//* Followed by:* - Exactly (length - 4) (possibly 0) bytes containing OXM TLVs, then* - Exactly ((length + 7)/8*8 - length) (between 0 and 7) bytes of* all-zero bytes* In summary, ofp_match is padded as needed, to make its overall size* a multiple of 8, to preserve alignement in structures using it.*/uint8_t oxm_fields[4]; /* OXMs start here - Make compiler happy */
};
OFP_ASSERT(sizeof(struct ofp_match) == 8);

/* The match type indicates the match structure (set of fields that compose the
* match) in use. The match type is placed in the type field at the beginning
* of all match structures. The "OpenFlow Extensible Match" type corresponds
* to OXM TLV format described below and must be supported by all OpenFlow
* switches. Extensions that define other match types may be published on the
* ONF wiki. Support for extensions is optional.
*/
enum ofp_match_type {OFPMT_STANDARD = 0, /* Deprecated. */OFPMT_OXM = 1, /* OpenFlow Extensible Match */
};

/* OXM Class IDs.
* The high order bit differentiate reserved classes from member classes.
* Classes 0x0000 to 0x7FFF are member classes, allocated by ONF.
* Classes 0x8000 to 0xFFFE are reserved classes, reserved for standardisation.
*/
enum ofp_oxm_class {OFPXMC_NXM_0 = 0x0000, /* Backward compatibility with NXM */OFPXMC_NXM_1 = 0x0001, /* Backward compatibility with NXM */OFPXMC_OPENFLOW_BASIC = 0x8000, /* Basic class for OpenFlow */OFPXMC_EXPERIMENTER = 0xFFFF, /* Experimenter class */
};

/* OXM Flow match field types for OpenFlow basic class. */
enum oxm_ofb_match_fields {OFPXMT_OFB_IN_PORT = 0, /* Switch input port. */OFPXMT_OFB_IN_PHY_PORT = 1, /* Switch physical input port. */OFPXMT_OFB_METADATA = 2, /* Metadata passed between tables. */OFPXMT_OFB_ETH_DST = 3, /* Ethernet destination address. */OFPXMT_OFB_ETH_SRC = 4, /* Ethernet source address. */OFPXMT_OFB_ETH_TYPE = 5, /* Ethernet frame type. */OFPXMT_OFB_VLAN_VID = 6, /* VLAN id. */OFPXMT_OFB_VLAN_PCP = 7, /* VLAN priority. */OFPXMT_OFB_IP_DSCP = 8, /* IP DSCP (6 bits in ToS field). */OFPXMT_OFB_IP_ECN = 9, /* IP ECN (2 bits in ToS field). */OFPXMT_OFB_IP_PROTO = 10, /* IP protocol. */OFPXMT_OFB_IPV4_SRC = 11, /* IPv4 source address. */OFPXMT_OFB_IPV4_DST = 12, /* IPv4 destination address. */OFPXMT_OFB_TCP_SRC = 13, /* TCP source port. */OFPXMT_OFB_TCP_DST = 14, /* TCP destination port. */OFPXMT_OFB_UDP_SRC = 15, /* UDP source port. */OFPXMT_OFB_UDP_DST = 16, /* UDP destination port. */OFPXMT_OFB_SCTP_SRC = 17, /* SCTP source port. */OFPXMT_OFB_SCTP_DST = 18, /* SCTP destination port. */OFPXMT_OFB_ICMPV4_TYPE = 19, /* ICMP type. */OFPXMT_OFB_ICMPV4_CODE = 20, /* ICMP code. */OFPXMT_OFB_ARP_OP = 21, /* ARP opcode. */OFPXMT_OFB_ARP_SPA = 22, /* ARP source IPv4 address. */OFPXMT_OFB_ARP_TPA = 23, /* ARP target IPv4 address. */OFPXMT_OFB_ARP_SHA = 24, /* ARP source hardware address. */OFPXMT_OFB_ARP_THA = 25, /* ARP target hardware address. */OFPXMT_OFB_IPV6_SRC = 26, /* IPv6 source address. */OFPXMT_OFB_IPV6_DST = 27, /* IPv6 destination address. */OFPXMT_OFB_IPV6_FLABEL = 28, /* IPv6 Flow Label */OFPXMT_OFB_ICMPV6_TYPE = 29, /* ICMPv6 type. */OFPXMT_OFB_ICMPV6_CODE = 30, /* ICMPv6 code. */OFPXMT_OFB_IPV6_ND_TARGET = 31, /* Target address for ND. */OFPXMT_OFB_IPV6_ND_SLL = 32, /* Source link-layer for ND. */OFPXMT_OFB_IPV6_ND_TLL = 33, /* Target link-layer for ND. */OFPXMT_OFB_MPLS_LABEL = 34, /* MPLS label. */OFPXMT_OFB_MPLS_TC = 35, /* MPLS TC. */OFPXMT_OFP_MPLS_BOS = 36, /* MPLS BoS bit. */OFPXMT_OFB_PBB_ISID = 37, /* PBB I-SID. */OFPXMT_OFB_TUNNEL_ID = 38, /* Logical Port Metadata. */OFPXMT_OFB_IPV6_EXTHDR = 39, /* IPv6 Extension Header pseudo-field */
};

匹配域的细节表：

of指令type：

enum ofp_instruction_type {OFPIT_GOTO_TABLE = 1, /* Setup the next table in the lookuppipeline */OFPIT_WRITE_METADATA = 2, /* Setup the metadata field for use later inpipeline */OFPIT_WRITE_ACTIONS = 3, /* Write the action(s) onto the datapath actionset */OFPIT_APPLY_ACTIONS = 4, /* Applies the action(s) immediately */OFPIT_CLEAR_ACTIONS = 5, /* Clears all actions from the datapathaction set */OFPIT_METER = 6, /* Apply meter (rate limiter) */OFPIT_EXPERIMENTER = 0xFFFF /* Experimenter instruction */
};

enum ofp_action_type {OFPAT_OUTPUT = 0, /* Output to switch port. */OFPAT_COPY_TTL_OUT = 11, /* Copy TTL "outwards" -- from next-to-outermostto outermost */OFPAT_COPY_TTL_IN = 12, /* Copy TTL "inwards" -- from outermost tonext-to-outermost */OFPAT_SET_MPLS_TTL = 15, /* MPLS TTL */OFPAT_DEC_MPLS_TTL = 16, /* Decrement MPLS TTL */OFPAT_PUSH_VLAN = 17, /* Push a new VLAN tag */OFPAT_POP_VLAN = 18, /* Pop the outer VLAN tag */OFPAT_PUSH_MPLS = 19, /* Push a new MPLS tag */OFPAT_POP_MPLS = 20, /* Pop the outer MPLS tag */OFPAT_SET_QUEUE = 21, /* Set queue id when outputting to a port */OFPAT_GROUP = 22, /* Apply group. */OFPAT_SET_NW_TTL = 23, /* IP TTL. */OFPAT_DEC_NW_TTL = 24, /* Decrement IP TTL. */OFPAT_SET_FIELD = 25, /* Set a header field using OXM TLV format. */OFPAT_PUSH_PBB = 26, /* Push a new PBB service tag (I-TAG) */OFPAT_POP_PBB = 27, /* Pop the outer PBB service tag (I-TAG) */OFPAT_EXPERIMENTER = 0xffff
};

controller-to-switch 消息

/* Switch features. */
struct ofp_switch_features {struct ofp_header header;uint64_t datapath_id; /* Datapath unique ID. The lower 48-bits are fora MAC address, while the upper 16-bits areimplementer-defined. */uint32_t n_buffers; /* Max packets buffered at once. */uint8_t n_tables; /* Number of tables supported by datapath. */uint8_t auxiliary_id; /* Identify auxiliary connections */uint8_t pad[2]; /* Align to 64-bits. *//* Features. */uint32_t capabilities; /* Bitmap of support "ofp_capabilities". */uint32_t reserved;
};
OFP_ASSERT(sizeof(struct ofp_switch_features) == 32);

/* Capabilities supported by the datapath. */
enum ofp_capabilities {OFPC_FLOW_STATS = 1 << 0, /* Flow statistics. */OFPC_TABLE_STATS = 1 << 1, /* Table statistics. */OFPC_PORT_STATS = 1 << 2, /* Port statistics. */OFPC_GROUP_STATS = 1 << 3, /* Group statistics. */OFPC_IP_REASM = 1 << 5, /* Can reassemble IP fragments. */OFPC_QUEUE_STATS = 1 << 6, /* Queue statistics. */OFPC_PORT_BLOCKED = 1 << 8 /* Switch will block looping ports. */
};

OFPT_GET_CONFIG_REPLY:

/* Switch configuration. */
struct ofp_switch_config {struct ofp_header header;uint16_t flags; /* OFPC_* flags. */uint16_t miss_send_len; /* Max bytes of packet that datapathshould send to the controller. Seeofp_controller_max_len for valid values.*/
};
OFP_ASSERT(sizeof(struct ofp_switch_config) == 12);

/* Table numbering. Tables can use any number up to OFPT_MAX. */
enum ofp_table {/* Last usable table number. */OFPTT_MAX = 0xfe,/* Fake tables. */OFPTT_ALL = 0xff /* Wildcard table used for table config,flow stats and flow deletes. */
};

/* Configure/Modify behavior of a flow table */
struct ofp_table_mod {struct ofp_header header;uint8_t table_id; /* ID of the table, OFPTT_ALL indicates all tables */uint8_t pad[3]; /* Pad to 32 bits */uint32_t config; /* Bitmap of OFPTC_* flags */};
OFP_ASSERT(sizeof(struct ofp_table_mod) == 16);

/* Flow setup and teardown (controller -> datapath). */
struct ofp_flow_mod {struct ofp_header header;uint64_t cookie; /* Opaque controller-issued identifier. */uint64_t cookie_mask; /* Mask used to restrict the cookie bitsthat must match when the command isOFPFC_MODIFY* or OFPFC_DELETE*. A valueof 0 indicates no restriction. *//* Flow actions. */uint8_t table_id; /* ID of the table to put the flow in.For OFPFC_DELETE_* commands, OFPTT_ALLcan also be used to delete matchingflows from all tables. */uint8_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, orOFP_NO_BUFFER.Not meaningful for OFPFC_DELETE*. */uint32_t out_port; /* For OFPFC_DELETE* commands, requirematching entries to include this as anoutput port. A value of OFPP_ANYindicates no restriction. */uint32_t out_group; /* For OFPFC_DELETE* commands, requirematching entries to include this as anoutput group. A value of OFPG_ANYindicates no restriction. */uint16_t flags; /* One of OFPFF_*. */uint8_t pad[2];struct ofp_match match; /* Fields to match. Variable size. *///struct ofp_instruction instructions[0]; /* Instruction set */
};OFP_ASSERT(sizeof(struct ofp_flow_mod) == 56);

enum ofp_flow_mod_command {OFPFC_ADD = 0, /* New flow. */OFPFC_MODIFY = 1, /* Modify all matching flows. */OFPFC_MODIFY_STRICT = 2, /* Modify entry strictly matching wildcards andpriority. */OFPFC_DELETE = 3, /* Delete all matching flows. */OFPFC_DELETE_STRICT = 4, /* Delete entry strictly matching wildcards andpriority. */
};

Error Message

该部分会经常用到，下发流表时由于违反某些规定而返回的错误：

/* OFPT_ERROR: Error message (datapath -> controller). */
struct ofp_error_msg {struct ofp_header header;uint16_t type;uint16_t code;uint8_t data[0]; /* Variable-length data. Interpreted basedon the type and code. No padding. */
};
OFP_ASSERT(sizeof(struct ofp_error_msg) == 12);

/* Values for ’type’ in ofp_error_message. These values are immutable: they
* will not change in future versions of the protocol (although new values may
* be added). */
enum ofp_error_type {OFPET_HELLO_FAILED = 0, /* Hello protocol failed. */OFPET_BAD_REQUEST = 1, /* Request was not understood. */OFPET_BAD_ACTION = 2, /* Error in action description. */OFPET_BAD_INSTRUCTION = 3, /* Error in instruction list. */OFPET_BAD_MATCH = 4, /* Error in match. */OFPET_FLOW_MOD_FAILED = 5, /* Problem modifying flow entry. */OFPET_GROUP_MOD_FAILED = 6, /* Problem modifying group entry. */OFPET_PORT_MOD_FAILED = 7, /* Port mod request failed. */OFPET_TABLE_MOD_FAILED = 8, /* Table mod request failed. */OFPET_QUEUE_OP_FAILED = 9, /* Queue operation failed. */OFPET_SWITCH_CONFIG_FAILED = 10, /* Switch config request failed. */OFPET_ROLE_REQUEST_FAILED = 11, /* Controller Role request failed. */OFPET_METER_MOD_FAILED = 12, /* Error in meter. */OFPET_TABLE_FEATURES_FAILED = 13, /* Setting table features failed. */OFPET_EXPERIMENTER = 0xffff /* Experimenter error messages. */
};

/* ofp_error_msg ’code’ values for OFPET_HELLO_FAILED. ’data’ contains an
* ASCII text string that may give failure details. */
enum ofp_hello_failed_code {OFPHFC_INCOMPATIBLE = 0, /* No compatible version. */OFPHFC_EPERM = 1, /* Permissions error. */
};

/* ofp_error_msg ’code’ values for OFPET_BAD_REQUEST. ’data’ contains at least
* the first 64 bytes of the failed request. */
enum ofp_bad_request_code {OFPBRC_BAD_VERSION = 0, /* ofp_header.version not supported. */OFPBRC_BAD_TYPE = 1, /* ofp_header.type not supported. */OFPBRC_BAD_MULTIPART = 2, /* ofp_multipart_request.type not supported. */OFPBRC_BAD_EXPERIMENTER = 3, /* Experimenter id not supported* (in ofp_experimenter_header or* ofp_multipart_request or* ofp_multipart_reply). */OFPBRC_BAD_EXP_TYPE = 4, /* Experimenter type not supported. */OFPBRC_EPERM = 5, /* Permissions error. */OFPBRC_BAD_LEN = 6, /* Wrong request length for type. */OFPBRC_BUFFER_EMPTY = 7, /* Specified buffer has already been used. */OFPBRC_BUFFER_UNKNOWN = 8, /* Specified buffer does not exist. */OFPBRC_BAD_TABLE_ID = 9, /* Specified table-id invalid or does not* exist. */OFPBRC_IS_SLAVE = 10, /* Denied because controller is slave. */OFPBRC_BAD_PORT = 11, /* Invalid port. */OFPBRC_BAD_PACKET = 12, /* Invalid packet in packet-out. */OFPBRC_MULTIPART_BUFFER_OVERFLOW = 13, /* ofp_multipart_requestoverflowed the assigned buffer. */
};

/* ofp_error_msg ’code’ values for OFPET_BAD_ACTION. ’data’ contains at least
* the first 64 bytes of the failed request. */
enum ofp_bad_action_code {OFPBAC_BAD_TYPE = 0, /* Unknown action type. */OFPBAC_BAD_LEN = 1, /* Length problem in actions. */OFPBAC_BAD_EXPERIMENTER = 2, /* Unknown experimenter id specified. */OFPBAC_BAD_EXP_TYPE = 3, /* Unknown action for experimenter id. */OFPBAC_BAD_OUT_PORT = 4, /* Problem validating output port. */OFPBAC_BAD_ARGUMENT = 5, /* Bad action argument. */OFPBAC_EPERM = 6, /* Permissions error. */OFPBAC_TOO_MANY = 7, /* Can’t handle this many actions. */OFPBAC_BAD_QUEUE = 8, /* Problem validating output queue. */OFPBAC_BAD_OUT_GROUP = 9, /* Invalid group id in forward action. */OFPBAC_MATCH_INCONSISTENT = 10, /* Action can’t apply for this match,or Set-Field missing prerequisite. */OFPBAC_UNSUPPORTED_ORDER = 11, /* Action order is unsupported for theaction list in an Apply-Actions instruction */OFPBAC_BAD_TAG = 12, /* Actions uses an unsupportedtag/encap. */OFPBAC_BAD_SET_TYPE = 13, /* Unsupported type in SET_FIELD action. */OFPBAC_BAD_SET_LEN = 14, /* Length problem in SET_FIELD action. */OFPBAC_BAD_SET_ARGUMENT = 15, /* Bad argument in SET_FIELD action. */
};

/* ofp_error_msg ’code’ values for OFPET_BAD_INSTRUCTION. ’data’ contains at least
* the first 64 bytes of the failed request. */
enum ofp_bad_instruction_code {OFPBIC_UNKNOWN_INST = 0, /* Unknown instruction. */OFPBIC_UNSUP_INST = 1, /* Switch or table does not support the instruction. */OFPBIC_BAD_TABLE_ID = 2, /* Invalid Table-ID specified. */OFPBIC_UNSUP_METADATA = 3, /* Metadata value unsupported by datapath. */OFPBIC_UNSUP_METADATA_MASK = 4, /* Metadata mask value unsupported bydatapath. */OFPBIC_BAD_EXPERIMENTER = 5, /* Unknown experimenter id specified. */OFPBIC_BAD_EXP_TYPE = 6, /* Unknown instruction for experimenter id. */OFPBIC_BAD_LEN = 7, /* Length problem in instructions. */OFPBIC_EPERM = 8, /* Permissions error. */
};

/* ofp_error_msg ’code’ values for OFPET_BAD_MATCH. ’data’ contains at least
* the first 64 bytes of the failed request. */
enum ofp_bad_match_code {OFPBMC_BAD_TYPE = 0, /* Unsupported match type specified by the match */OFPBMC_BAD_LEN = 1, /* Length problem in match. */OFPBMC_BAD_TAG = 2, /* Match uses an unsupported tag/encap. */OFPBMC_BAD_DL_ADDR_MASK = 3, /* Unsupported datalink addr mask - switchdoes not support arbitrary datalinkaddress mask. */OFPBMC_BAD_NW_ADDR_MASK = 4, /* Unsupported network addr mask - switchdoes not support arbitrary networkaddress mask. */OFPBMC_BAD_WILDCARDS = 5, /* Unsupported combination of fields maskedor omitted in the match. */OFPBMC_BAD_FIELD = 6, /* Unsupported field type in the match. */OFPBMC_BAD_VALUE = 7, /* Unsupported value in a match field. */OFPBMC_BAD_MASK = 8, /* Unsupported mask specified in the match,field is not dl-address or nw-address. */OFPBMC_BAD_PREREQ = 9, /* A prerequisite was not met. */OFPBMC_DUP_FIELD = 10, /* A field type was duplicated. */OFPBMC_EPERM = 11, /* Permissions error. */
};

/* ofp_error_msg ’code’ values for OFPET_FLOW_MOD_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request. */
enum ofp_flow_mod_failed_code {OFPFMFC_UNKNOWN = 0, /* Unspecified error. */OFPFMFC_TABLE_FULL = 1, /* Flow not added because table was full. */OFPFMFC_BAD_TABLE_ID = 2, /* Table does not exist */OFPFMFC_OVERLAP = 3, /* Attempted to add overlapping flow withCHECK_OVERLAP flag set. */OFPFMFC_EPERM = 4, /* Permissions error. */OFPFMFC_BAD_TIMEOUT = 5, /* Flow not added because of unsupportedidle/hard timeout. */OFPFMFC_BAD_COMMAND = 6, /* Unsupported or unknown command. */OFPFMFC_BAD_FLAGS = 7, /* Unsupported or unknown flags. */
};

/* ofp_error_msg ’code’ values for OFPET_GROUP_MOD_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request. */
enum ofp_group_mod_failed_code {OFPGMFC_GROUP_EXISTS = 0, /* Group not added because a group ADDattempted to replace analready-present group. */OFPGMFC_INVALID_GROUP = 1, /* Group not added because Groupspecified is invalid. */OFPGMFC_WEIGHT_UNSUPPORTED = 2, /* Switch does not support unequal loadsharing with select groups. */OFPGMFC_OUT_OF_GROUPS = 3, /* The group table is full. */OFPGMFC_OUT_OF_BUCKETS = 4, /* The maximum number of action bucketsfor a group has been exceeded. */OFPGMFC_CHAINING_UNSUPPORTED = 5, /* Switch does not support groups thatforward to groups. */OFPGMFC_WATCH_UNSUPPORTED = 6, /* This group cannot watch the watch_portor watch_group specified. */OFPGMFC_LOOP = 7, /* Group entry would cause a loop. */OFPGMFC_UNKNOWN_GROUP = 8, /* Group not modified because a groupMODIFY attempted to modify anon-existent group. */OFPGMFC_CHAINED_GROUP = 9, /* Group not deleted because anothergroup is forwarding to it. */OFPGMFC_BAD_TYPE = 10, /* Unsupported or unknown group type. */OFPGMFC_BAD_COMMAND = 11, /* Unsupported or unknown command. */OFPGMFC_BAD_BUCKET = 12, /* Error in bucket. */OFPGMFC_BAD_WATCH = 13, /* Error in watch port/group. */OFPGMFC_EPERM = 14, /* Permissions error. */
};

/* ofp_error_msg ’code’ values for OFPET_PORT_MOD_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request. */
enum ofp_port_mod_failed_code {OFPPMFC_BAD_PORT = 0, /* Specified port number does not exist. */OFPPMFC_BAD_HW_ADDR = 1, /* Specified hardware address does not* match the port number. */OFPPMFC_BAD_CONFIG = 2, /* Specified config is invalid. */OFPPMFC_BAD_ADVERTISE = 3, /* Specified advertise is invalid. */OFPPMFC_EPERM = 4, /* Permissions error. */
};

/* ofp_error_msg ’code’ values for OFPET_TABLE_MOD_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request. */
enum ofp_table_mod_failed_code {OFPTMFC_BAD_TABLE = 0, /* Specified table does not exist. */OFPTMFC_BAD_CONFIG = 1, /* Specified config is invalid. */OFPTMFC_EPERM = 2, /* Permissions error. */
};

/* ofp_error msg ’code’ values for OFPET_QUEUE_OP_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request */
enum ofp_queue_op_failed_code {OFPQOFC_BAD_PORT = 0, /* Invalid port (or port does not exist). */OFPQOFC_BAD_QUEUE = 1, /* Queue does not exist. */OFPQOFC_EPERM = 2, /* Permissions error. */
};

/* ofp_error_msg ’code’ values for OFPET_SWITCH_CONFIG_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request. */
enum ofp_switch_config_failed_code {OFPSCFC_BAD_FLAGS = 0, /* Specified flags is invalid. */OFPSCFC_BAD_LEN = 1, /* Specified len is invalid. */OFPQCFC_EPERM = 2, /* Permissions error. */
};

/* ofp_error_msg ’code’ values for OFPET_ROLE_REQUEST_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request. */
enum ofp_role_request_failed_code {OFPRRFC_STALE = 0, /* Stale Message: old generation_id. */OFPRRFC_UNSUP = 1, /* Controller role change unsupported. */OFPRRFC_BAD_ROLE = 2, /* Invalid role. */
};

/* ofp_error_msg ’code’ values for OFPET_METER_MOD_FAILED. ’data’ contains
* at least the first 64 bytes of the failed request. */
enum ofp_meter_mod_failed_code {OFPMMFC_UNKNOWN = 0, /* Unspecified error. */OFPMMFC_METER_EXISTS = 1, /* Meter not added because a Meter ADD* attempted to replace an existing Meter. */OFPMMFC_INVALID_METER = 2, /* Meter not added because Meter specified* is invalid. */OFPMMFC_UNKNOWN_METER = 3, /* Meter not modified because a MeterMODIFY attempted to modify a non-existentMeter. */OFPMMFC_BAD_COMMAND = 4, /* Unsupported or unknown command. */OFPMMFC_BAD_FLAGS = 5, /* Flag configuration unsupported. */OFPMMFC_BAD_RATE = 6, /* Rate unsupported. */OFPMMFC_BAD_BURST = 7, /* Burst size unsupported. */OFPMMFC_BAD_BAND = 8, /* Band unsupported. */OFPMMFC_BAD_BAND_VALUE = 9, /* Band value unsupported. */OFPMMFC_OUT_OF_METERS = 10, /* No more meters available. */OFPMMFC_OUT_OF_BANDS = 11, /* The maximum number of properties* for a meter has been exceeded. */};For the OFPET_TABLE_FEATURES_FAILED error type, the following codes are currently defined:/* ofp_error_msg ’code’ values for OFPET_TABLE_FEATURES_FAILED. ’data’ contains* at least the first 64 bytes of the failed request. */enum ofp_table_features_failed_code {OFPTFFC_BAD_TABLE = 0, /* Specified table does not exist. */OFPTFFC_BAD_METADATA = 1, /* Invalid metadata mask. */OFPTFFC_BAD_TYPE = 2, /* Unknown property type. */OFPTFFC_BAD_LEN = 3, /* Length problem in properties. */OFPTFFC_BAD_ARGUMENT = 4, /* Unsupported property value. */OFPTFFC_EPERM = 5, /* Permissions error. */
};

fields, followed by experimenter defined data:
/* OFPET_EXPERIMENTER: Error message (datapath -> controller). */
struct ofp_error_experimenter_msg {struct ofp_header header;uint16_t type; /* OFPET_EXPERIMENTER. */uint16_t exp_type; /* Experimenter defined. */uint32_t experimenter; /* Experimenter ID which takes the same formas in struct ofp_experimenter_header. */uint8_t data[0]; /* Variable-length data. Interpreted basedon the type and code. No padding. */
};
OFP_ASSERT(sizeof(struct ofp_error_experimenter_msg) == 16);

参考

https://opennetworking.org/wp-content/uploads/2014/10/openflow-spec-v1.3.0.pdf
https://info.support.huawei.com/info-finder/encyclopedia/zh/OpenFlow.html
https://www.cnblogs.com/CasonChan/p/4626099.html