Edit File: netif.h
/****************************************************************************** * netif.h * * Unified network-device I/O interface for Xen guest OSes. * * Copyright (c) 2003-2004, Keir Fraser */ #ifndef __XEN_PUBLIC_IO_NETIF_H__ #define __XEN_PUBLIC_IO_NETIF_H__ #include <xen/interface/io/ring.h> #include <xen/interface/grant_table.h> /* * Older implementation of Xen network frontend / backend has an * implicit dependency on the MAX_SKB_FRAGS as the maximum number of * ring slots a skb can use. Netfront / netback may not work as * expected when frontend and backend have different MAX_SKB_FRAGS. * * A better approach is to add mechanism for netfront / netback to * negotiate this value. However we cannot fix all possible * frontends, so we need to define a value which states the minimum * slots backend must support. * * The minimum value derives from older Linux kernel's MAX_SKB_FRAGS * (18), which is proved to work with most frontends. Any new backend * which doesn't negotiate with frontend should expect frontend to * send a valid packet using slots up to this value. */ #define XEN_NETIF_NR_SLOTS_MIN 18 /* * Notifications after enqueuing any type of message should be conditional on * the appropriate req_event or rsp_event field in the shared ring. * If the client sends notification for rx requests then it should specify * feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume * that it cannot safely queue packets (as it may not be kicked to send them). */ /* * "feature-split-event-channels" is introduced to separate guest TX * and RX notificaion. Backend either doesn't support this feature or * advertise it via xenstore as 0 (disabled) or 1 (enabled). * * To make use of this feature, frontend should allocate two event * channels for TX and RX, advertise them to backend as * "event-channel-tx" and "event-channel-rx" respectively. If frontend * doesn't want to use this feature, it just writes "event-channel" * node as before. */ /* * "feature-gso-tcpv4" and "feature-gso-tcpv6" advertise the capability to * handle large TCP packets (in IPv4 or IPv6 form respectively). Neither * frontends nor backends are assumed to be capable unless the flags are * present. */ /* * This is the 'wire' format for packets: * Request 1: xen_netif_tx_request -- XEN_NETTXF_* (any flags) * [Request 2: xen_netif_extra_info] (only if request 1 has XEN_NETTXF_extra_info) * [Request 3: xen_netif_extra_info] (only if request 2 has XEN_NETIF_EXTRA_MORE) * Request 4: xen_netif_tx_request -- XEN_NETTXF_more_data * Request 5: xen_netif_tx_request -- XEN_NETTXF_more_data * ... * Request N: xen_netif_tx_request -- 0 */ /* Protocol checksum field is blank in the packet (hardware offload)? */ #define _XEN_NETTXF_csum_blank (0) #define XEN_NETTXF_csum_blank (1U<<_XEN_NETTXF_csum_blank) /* Packet data has been validated against protocol checksum. */ #define _XEN_NETTXF_data_validated (1) #define XEN_NETTXF_data_validated (1U<<_XEN_NETTXF_data_validated) /* Packet continues in the next request descriptor. */ #define _XEN_NETTXF_more_data (2) #define XEN_NETTXF_more_data (1U<<_XEN_NETTXF_more_data) /* Packet to be followed by extra descriptor(s). */ #define _XEN_NETTXF_extra_info (3) #define XEN_NETTXF_extra_info (1U<<_XEN_NETTXF_extra_info) #define XEN_NETIF_MAX_TX_SIZE 0xFFFF struct xen_netif_tx_request { grant_ref_t gref; /* Reference to buffer page */ uint16_t offset; /* Offset within buffer page */ uint16_t flags; /* XEN_NETTXF_* */ uint16_t id; /* Echoed in response message. */ uint16_t size; /* Packet size in bytes. */ }; /* Types of xen_netif_extra_info descriptors. */ #define XEN_NETIF_EXTRA_TYPE_NONE (0) /* Never used - invalid */ #define XEN_NETIF_EXTRA_TYPE_GSO (1) /* u.gso */ #define XEN_NETIF_EXTRA_TYPE_MAX (2) /* xen_netif_extra_info flags. */ #define _XEN_NETIF_EXTRA_FLAG_MORE (0) #define XEN_NETIF_EXTRA_FLAG_MORE (1U<<_XEN_NETIF_EXTRA_FLAG_MORE) /* GSO types */ #define XEN_NETIF_GSO_TYPE_TCPV4 (1) #define XEN_NETIF_GSO_TYPE_TCPV6 (2) /* * This structure needs to fit within both netif_tx_request and * netif_rx_response for compatibility. */ struct xen_netif_extra_info { uint8_t type; /* XEN_NETIF_EXTRA_TYPE_* */ uint8_t flags; /* XEN_NETIF_EXTRA_FLAG_* */ union { struct { /* * Maximum payload size of each segment. For * example, for TCP this is just the path MSS. */ uint16_t size; /* * GSO type. This determines the protocol of * the packet and any extra features required * to segment the packet properly. */ uint8_t type; /* XEN_NETIF_GSO_TYPE_* */ /* Future expansion. */ uint8_t pad; /* * GSO features. This specifies any extra GSO * features required to process this packet, * such as ECN support for TCPv4. */ uint16_t features; /* XEN_NETIF_GSO_FEAT_* */ } gso; uint16_t pad[3]; } u; }; struct xen_netif_tx_response { uint16_t id; int16_t status; /* XEN_NETIF_RSP_* */ }; struct xen_netif_rx_request { uint16_t id; /* Echoed in response message. */ grant_ref_t gref; /* Reference to incoming granted frame */ }; /* Packet data has been validated against protocol checksum. */ #define _XEN_NETRXF_data_validated (0) #define XEN_NETRXF_data_validated (1U<<_XEN_NETRXF_data_validated) /* Protocol checksum field is blank in the packet (hardware offload)? */ #define _XEN_NETRXF_csum_blank (1) #define XEN_NETRXF_csum_blank (1U<<_XEN_NETRXF_csum_blank) /* Packet continues in the next request descriptor. */ #define _XEN_NETRXF_more_data (2) #define XEN_NETRXF_more_data (1U<<_XEN_NETRXF_more_data) /* Packet to be followed by extra descriptor(s). */ #define _XEN_NETRXF_extra_info (3) #define XEN_NETRXF_extra_info (1U<<_XEN_NETRXF_extra_info) /* GSO Prefix descriptor. */ #define _XEN_NETRXF_gso_prefix (4) #define XEN_NETRXF_gso_prefix (1U<<_XEN_NETRXF_gso_prefix) struct xen_netif_rx_response { uint16_t id; uint16_t offset; /* Offset in page of start of received packet */ uint16_t flags; /* XEN_NETRXF_* */ int16_t status; /* -ve: BLKIF_RSP_* ; +ve: Rx'ed pkt size. */ }; /* * Generate netif ring structures and types. */ DEFINE_RING_TYPES(xen_netif_tx, struct xen_netif_tx_request, struct xen_netif_tx_response); DEFINE_RING_TYPES(xen_netif_rx, struct xen_netif_rx_request, struct xen_netif_rx_response); #define XEN_NETIF_RSP_DROPPED -2 #define XEN_NETIF_RSP_ERROR -1 #define XEN_NETIF_RSP_OKAY 0 /* No response: used for auxiliary requests (e.g., xen_netif_extra_info). */ #define XEN_NETIF_RSP_NULL 1 #endif