From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 include/xen/interface/io/netif.h | 262 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 262 insertions(+)
 create mode 100644 include/xen/interface/io/netif.h

(limited to 'include/xen/interface/io/netif.h')

diff --git a/include/xen/interface/io/netif.h b/include/xen/interface/io/netif.h
new file mode 100644
index 000000000..70054cc07
--- /dev/null
+++ b/include/xen/interface/io/netif.h
@@ -0,0 +1,262 @@
+/******************************************************************************
+ * 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.
+ */
+
+/*
+ * Multiple transmit and receive queues:
+ * If supported, the backend will write the key "multi-queue-max-queues" to
+ * the directory for that vif, and set its value to the maximum supported
+ * number of queues.
+ * Frontends that are aware of this feature and wish to use it can write the
+ * key "multi-queue-num-queues", set to the number they wish to use, which
+ * must be greater than zero, and no more than the value reported by the backend
+ * in "multi-queue-max-queues".
+ *
+ * Queues replicate the shared rings and event channels.
+ * "feature-split-event-channels" may optionally be used when using
+ * multiple queues, but is not mandatory.
+ *
+ * Each queue consists of one shared ring pair, i.e. there must be the same
+ * number of tx and rx rings.
+ *
+ * For frontends requesting just one queue, the usual event-channel and
+ * ring-ref keys are written as before, simplifying the backend processing
+ * to avoid distinguishing between a frontend that doesn't understand the
+ * multi-queue feature, and one that does, but requested only one queue.
+ *
+ * Frontends requesting two or more queues must not write the toplevel
+ * event-channel (or event-channel-{tx,rx}) and {tx,rx}-ring-ref keys,
+ * instead writing those keys under sub-keys having the name "queue-N" where
+ * N is the integer ID of the queue for which those keys belong. Queues
+ * are indexed from zero. For example, a frontend with two queues and split
+ * event channels must write the following set of queue-related keys:
+ *
+ * /local/domain/1/device/vif/0/multi-queue-num-queues = "2"
+ * /local/domain/1/device/vif/0/queue-0 = ""
+ * /local/domain/1/device/vif/0/queue-0/tx-ring-ref = "<ring-ref-tx0>"
+ * /local/domain/1/device/vif/0/queue-0/rx-ring-ref = "<ring-ref-rx0>"
+ * /local/domain/1/device/vif/0/queue-0/event-channel-tx = "<evtchn-tx0>"
+ * /local/domain/1/device/vif/0/queue-0/event-channel-rx = "<evtchn-rx0>"
+ * /local/domain/1/device/vif/0/queue-1 = ""
+ * /local/domain/1/device/vif/0/queue-1/tx-ring-ref = "<ring-ref-tx1>"
+ * /local/domain/1/device/vif/0/queue-1/rx-ring-ref = "<ring-ref-rx1"
+ * /local/domain/1/device/vif/0/queue-1/event-channel-tx = "<evtchn-tx1>"
+ * /local/domain/1/device/vif/0/queue-1/event-channel-rx = "<evtchn-rx1>"
+ *
+ * If there is any inconsistency in the XenStore data, the backend may
+ * choose not to connect any queues, instead treating the request as an
+ * error. This includes scenarios where more (or fewer) queues were
+ * requested than the frontend provided details for.
+ *
+ * Mapping of packets to queues is considered to be a function of the
+ * transmitting system (backend or frontend) and is not negotiated
+ * between the two. Guests are free to transmit packets on any queue
+ * they choose, provided it has been set up correctly. Guests must be
+ * prepared to receive packets on any queue they have requested be set up.
+ */
+
+/*
+ * "feature-no-csum-offload" should be used to turn IPv4 TCP/UDP checksum
+ * offload off or on. If it is missing then the feature is assumed to be on.
+ * "feature-ipv6-csum-offload" should be used to turn IPv6 TCP/UDP checksum
+ * offload on or off. If it is missing then the feature is assumed to be off.
+ */
+
+/*
+ * "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_NONE		(0)
+#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
-- 
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