1 /****************************************************************************** 2 * netif.h 3 * 4 * Unified network-device I/O interface for Xen guest OSes. 5 * 6 * Copyright (c) 2003-2004, Keir Fraser 7 */ 8 9 #ifndef __XEN_PUBLIC_IO_NETIF_H__ 10 #define __XEN_PUBLIC_IO_NETIF_H__ 11 12 #include "ring.h" 13 #include "../grant_table.h" 14 15 /* 16 * Older implementation of Xen network frontend / backend has an 17 * implicit dependency on the MAX_SKB_FRAGS as the maximum number of 18 * ring slots a skb can use. Netfront / netback may not work as 19 * expected when frontend and backend have different MAX_SKB_FRAGS. 20 * 21 * A better approach is to add mechanism for netfront / netback to 22 * negotiate this value. However we cannot fix all possible 23 * frontends, so we need to define a value which states the minimum 24 * slots backend must support. 25 * 26 * The minimum value derives from older Linux kernel's MAX_SKB_FRAGS 27 * (18), which is proved to work with most frontends. Any new backend 28 * which doesn't negotiate with frontend should expect frontend to 29 * send a valid packet using slots up to this value. 30 */ 31 #define XEN_NETIF_NR_SLOTS_MIN 18 32 33 /* 34 * Notifications after enqueuing any type of message should be conditional on 35 * the appropriate req_event or rsp_event field in the shared ring. 36 * If the client sends notification for rx requests then it should specify 37 * feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume 38 * that it cannot safely queue packets (as it may not be kicked to send them). 39 */ 40 41 /* 42 * This is the 'wire' format for packets: 43 * Request 1: xen_netif_tx_request -- XEN_NETTXF_* (any flags) 44 * [Request 2: xen_netif_extra_info] (only if request 1 has XEN_NETTXF_extra_info) 45 * [Request 3: xen_netif_extra_info] (only if request 2 has XEN_NETIF_EXTRA_MORE) 46 * Request 4: xen_netif_tx_request -- XEN_NETTXF_more_data 47 * Request 5: xen_netif_tx_request -- XEN_NETTXF_more_data 48 * ... 49 * Request N: xen_netif_tx_request -- 0 50 */ 51 52 /* Protocol checksum field is blank in the packet (hardware offload)? */ 53 #define _XEN_NETTXF_csum_blank (0) 54 #define XEN_NETTXF_csum_blank (1U<<_XEN_NETTXF_csum_blank) 55 56 /* Packet data has been validated against protocol checksum. */ 57 #define _XEN_NETTXF_data_validated (1) 58 #define XEN_NETTXF_data_validated (1U<<_XEN_NETTXF_data_validated) 59 60 /* Packet continues in the next request descriptor. */ 61 #define _XEN_NETTXF_more_data (2) 62 #define XEN_NETTXF_more_data (1U<<_XEN_NETTXF_more_data) 63 64 /* Packet to be followed by extra descriptor(s). */ 65 #define _XEN_NETTXF_extra_info (3) 66 #define XEN_NETTXF_extra_info (1U<<_XEN_NETTXF_extra_info) 67 68 #define XEN_NETIF_MAX_TX_SIZE 0xFFFF 69 struct xen_netif_tx_request { 70 grant_ref_t gref; /* Reference to buffer page */ 71 uint16_t offset; /* Offset within buffer page */ 72 uint16_t flags; /* XEN_NETTXF_* */ 73 uint16_t id; /* Echoed in response message. */ 74 uint16_t size; /* Packet size in bytes. */ 75 }; 76 77 /* Types of xen_netif_extra_info descriptors. */ 78 #define XEN_NETIF_EXTRA_TYPE_NONE (0) /* Never used - invalid */ 79 #define XEN_NETIF_EXTRA_TYPE_GSO (1) /* u.gso */ 80 #define XEN_NETIF_EXTRA_TYPE_MAX (2) 81 82 /* xen_netif_extra_info flags. */ 83 #define _XEN_NETIF_EXTRA_FLAG_MORE (0) 84 #define XEN_NETIF_EXTRA_FLAG_MORE (1U<<_XEN_NETIF_EXTRA_FLAG_MORE) 85 86 /* GSO types - only TCPv4 currently supported. */ 87 #define XEN_NETIF_GSO_TYPE_TCPV4 (1) 88 89 /* 90 * This structure needs to fit within both netif_tx_request and 91 * netif_rx_response for compatibility. 92 */ 93 struct xen_netif_extra_info { 94 uint8_t type; /* XEN_NETIF_EXTRA_TYPE_* */ 95 uint8_t flags; /* XEN_NETIF_EXTRA_FLAG_* */ 96 97 union { 98 struct { 99 /* 100 * Maximum payload size of each segment. For 101 * example, for TCP this is just the path MSS. 102 */ 103 uint16_t size; 104 105 /* 106 * GSO type. This determines the protocol of 107 * the packet and any extra features required 108 * to segment the packet properly. 109 */ 110 uint8_t type; /* XEN_NETIF_GSO_TYPE_* */ 111 112 /* Future expansion. */ 113 uint8_t pad; 114 115 /* 116 * GSO features. This specifies any extra GSO 117 * features required to process this packet, 118 * such as ECN support for TCPv4. 119 */ 120 uint16_t features; /* XEN_NETIF_GSO_FEAT_* */ 121 } gso; 122 123 uint16_t pad[3]; 124 } u; 125 }; 126 127 struct xen_netif_tx_response { 128 uint16_t id; 129 int16_t status; /* XEN_NETIF_RSP_* */ 130 }; 131 132 struct xen_netif_rx_request { 133 uint16_t id; /* Echoed in response message. */ 134 grant_ref_t gref; /* Reference to incoming granted frame */ 135 }; 136 137 /* Packet data has been validated against protocol checksum. */ 138 #define _XEN_NETRXF_data_validated (0) 139 #define XEN_NETRXF_data_validated (1U<<_XEN_NETRXF_data_validated) 140 141 /* Protocol checksum field is blank in the packet (hardware offload)? */ 142 #define _XEN_NETRXF_csum_blank (1) 143 #define XEN_NETRXF_csum_blank (1U<<_XEN_NETRXF_csum_blank) 144 145 /* Packet continues in the next request descriptor. */ 146 #define _XEN_NETRXF_more_data (2) 147 #define XEN_NETRXF_more_data (1U<<_XEN_NETRXF_more_data) 148 149 /* Packet to be followed by extra descriptor(s). */ 150 #define _XEN_NETRXF_extra_info (3) 151 #define XEN_NETRXF_extra_info (1U<<_XEN_NETRXF_extra_info) 152 153 /* GSO Prefix descriptor. */ 154 #define _XEN_NETRXF_gso_prefix (4) 155 #define XEN_NETRXF_gso_prefix (1U<<_XEN_NETRXF_gso_prefix) 156 157 struct xen_netif_rx_response { 158 uint16_t id; 159 uint16_t offset; /* Offset in page of start of received packet */ 160 uint16_t flags; /* XEN_NETRXF_* */ 161 int16_t status; /* -ve: BLKIF_RSP_* ; +ve: Rx'ed pkt size. */ 162 }; 163 164 /* 165 * Generate netif ring structures and types. 166 */ 167 168 DEFINE_RING_TYPES(xen_netif_tx, 169 struct xen_netif_tx_request, 170 struct xen_netif_tx_response); 171 DEFINE_RING_TYPES(xen_netif_rx, 172 struct xen_netif_rx_request, 173 struct xen_netif_rx_response); 174 175 #define XEN_NETIF_RSP_DROPPED -2 176 #define XEN_NETIF_RSP_ERROR -1 177 #define XEN_NETIF_RSP_OKAY 0 178 /* No response: used for auxiliary requests (e.g., xen_netif_extra_info). */ 179 #define XEN_NETIF_RSP_NULL 1 180 181 #endif 182