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netif.h
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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 <xen/interface/io/ring.h>
14 
15 /*
16  * Notifications after enqueuing any type of message should be conditional on
17  * the appropriate req_event or rsp_event field in the shared ring.
18  * If the client sends notification for rx requests then it should specify
19  * feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume
20  * that it cannot safely queue packets (as it may not be kicked to send them).
21  */
22 
23 /*
24  * This is the 'wire' format for packets:
25  * Request 1: xen_netif_tx_request -- XEN_NETTXF_* (any flags)
26  * [Request 2: xen_netif_extra_info] (only if request 1 has XEN_NETTXF_extra_info)
27  * [Request 3: xen_netif_extra_info] (only if request 2 has XEN_NETIF_EXTRA_MORE)
28  * Request 4: xen_netif_tx_request -- XEN_NETTXF_more_data
29  * Request 5: xen_netif_tx_request -- XEN_NETTXF_more_data
30  * ...
31  * Request N: xen_netif_tx_request -- 0
32  */
33 
34 /* Protocol checksum field is blank in the packet (hardware offload)? */
35 #define _XEN_NETTXF_csum_blank (0)
36 #define XEN_NETTXF_csum_blank (1U<<_XEN_NETTXF_csum_blank)
37 
38 /* Packet data has been validated against protocol checksum. */
39 #define _XEN_NETTXF_data_validated (1)
40 #define XEN_NETTXF_data_validated (1U<<_XEN_NETTXF_data_validated)
41 
42 /* Packet continues in the next request descriptor. */
43 #define _XEN_NETTXF_more_data (2)
44 #define XEN_NETTXF_more_data (1U<<_XEN_NETTXF_more_data)
45 
46 /* Packet to be followed by extra descriptor(s). */
47 #define _XEN_NETTXF_extra_info (3)
48 #define XEN_NETTXF_extra_info (1U<<_XEN_NETTXF_extra_info)
49 
51  grant_ref_t gref; /* Reference to buffer page */
52  uint16_t offset; /* Offset within buffer page */
53  uint16_t flags; /* XEN_NETTXF_* */
54  uint16_t id; /* Echoed in response message. */
55  uint16_t size; /* Packet size in bytes. */
56 };
57 
58 /* Types of xen_netif_extra_info descriptors. */
59 #define XEN_NETIF_EXTRA_TYPE_NONE (0) /* Never used - invalid */
60 #define XEN_NETIF_EXTRA_TYPE_GSO (1) /* u.gso */
61 #define XEN_NETIF_EXTRA_TYPE_MAX (2)
62 
63 /* xen_netif_extra_info flags. */
64 #define _XEN_NETIF_EXTRA_FLAG_MORE (0)
65 #define XEN_NETIF_EXTRA_FLAG_MORE (1U<<_XEN_NETIF_EXTRA_FLAG_MORE)
66 
67 /* GSO types - only TCPv4 currently supported. */
68 #define XEN_NETIF_GSO_TYPE_TCPV4 (1)
69 
70 /*
71  * This structure needs to fit within both netif_tx_request and
72  * netif_rx_response for compatibility.
73  */
75  uint8_t type; /* XEN_NETIF_EXTRA_TYPE_* */
76  uint8_t flags; /* XEN_NETIF_EXTRA_FLAG_* */
77 
78  union {
79  struct {
80  /*
81  * Maximum payload size of each segment. For
82  * example, for TCP this is just the path MSS.
83  */
85 
86  /*
87  * GSO type. This determines the protocol of
88  * the packet and any extra features required
89  * to segment the packet properly.
90  */
91  uint8_t type; /* XEN_NETIF_GSO_TYPE_* */
92 
93  /* Future expansion. */
95 
96  /*
97  * GSO features. This specifies any extra GSO
98  * features required to process this packet,
99  * such as ECN support for TCPv4.
100  */
101  uint16_t features; /* XEN_NETIF_GSO_FEAT_* */
102  } gso;
103 
105  } u;
106 };
107 
110  int16_t status; /* XEN_NETIF_RSP_* */
111 };
112 
114  uint16_t id; /* Echoed in response message. */
115  grant_ref_t gref; /* Reference to incoming granted frame */
116 };
117 
118 /* Packet data has been validated against protocol checksum. */
119 #define _XEN_NETRXF_data_validated (0)
120 #define XEN_NETRXF_data_validated (1U<<_XEN_NETRXF_data_validated)
121 
122 /* Protocol checksum field is blank in the packet (hardware offload)? */
123 #define _XEN_NETRXF_csum_blank (1)
124 #define XEN_NETRXF_csum_blank (1U<<_XEN_NETRXF_csum_blank)
125 
126 /* Packet continues in the next request descriptor. */
127 #define _XEN_NETRXF_more_data (2)
128 #define XEN_NETRXF_more_data (1U<<_XEN_NETRXF_more_data)
129 
130 /* Packet to be followed by extra descriptor(s). */
131 #define _XEN_NETRXF_extra_info (3)
132 #define XEN_NETRXF_extra_info (1U<<_XEN_NETRXF_extra_info)
133 
134 /* GSO Prefix descriptor. */
135 #define _XEN_NETRXF_gso_prefix (4)
136 #define XEN_NETRXF_gso_prefix (1U<<_XEN_NETRXF_gso_prefix)
137 
140  uint16_t offset; /* Offset in page of start of received packet */
141  uint16_t flags; /* XEN_NETRXF_* */
142  int16_t status; /* -ve: BLKIF_RSP_* ; +ve: Rx'ed pkt size. */
143 };
144 
145 /*
146  * Generate netif ring structures and types.
147  */
148 
149 DEFINE_RING_TYPES(xen_netif_tx,
150  struct xen_netif_tx_request,
151  struct xen_netif_tx_response);
152 DEFINE_RING_TYPES(xen_netif_rx,
153  struct xen_netif_rx_request,
154  struct xen_netif_rx_response);
155 
156 #define XEN_NETIF_RSP_DROPPED -2
157 #define XEN_NETIF_RSP_ERROR -1
158 #define XEN_NETIF_RSP_OKAY 0
159 /* No response: used for auxiliary requests (e.g., xen_netif_extra_info). */
160 #define XEN_NETIF_RSP_NULL 1
161 
162 #endif