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freebsd-dev/sys/dev/xen/netback/netback.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2009-2011 Spectra Logic Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* Authors: Justin T. Gibbs (Spectra Logic Corporation)
* Alan Somers (Spectra Logic Corporation)
* John Suykerbuyk (Spectra Logic Corporation)
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/**
* \file netback.c
*
* \brief Device driver supporting the vending of network access
* from this FreeBSD domain to other domains.
*/
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_types.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/tcp.h>
#include <netinet/ip_icmp.h>
#include <netinet/udp.h>
#include <machine/in_cksum.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <machine/_inttypes.h>
#include <xen/xen-os.h>
#include <xen/hypervisor.h>
#include <xen/xen_intr.h>
#include <contrib/xen/io/netif.h>
#include <xen/xenbus/xenbusvar.h>
/*--------------------------- Compile-time Tunables --------------------------*/
/*---------------------------------- Macros ----------------------------------*/
/**
* Custom malloc type for all driver allocations.
*/
static MALLOC_DEFINE(M_XENNETBACK, "xnb", "Xen Net Back Driver Data");
#define XNB_SG 1 /* netback driver supports feature-sg */
#define XNB_GSO_TCPV4 0 /* netback driver supports feature-gso-tcpv4 */
#define XNB_RX_COPY 1 /* netback driver supports feature-rx-copy */
#define XNB_RX_FLIP 0 /* netback driver does not support feature-rx-flip */
#undef XNB_DEBUG
#define XNB_DEBUG /* hardcode on during development */
#ifdef XNB_DEBUG
#define DPRINTF(fmt, args...) \
printf("xnb(%s:%d): " fmt, __FUNCTION__, __LINE__, ##args)
#else
#define DPRINTF(fmt, args...) do {} while (0)
#endif
/* Default length for stack-allocated grant tables */
#define GNTTAB_LEN (64)
/* Features supported by all backends. TSO and LRO can be negotiated */
#define XNB_CSUM_FEATURES (CSUM_TCP | CSUM_UDP)
#define NET_TX_RING_SIZE __RING_SIZE((netif_tx_sring_t *)0, PAGE_SIZE)
#define NET_RX_RING_SIZE __RING_SIZE((netif_rx_sring_t *)0, PAGE_SIZE)
/**
* Two argument version of the standard macro. Second argument is a tentative
* value of req_cons
*/
#define RING_HAS_UNCONSUMED_REQUESTS_2(_r, cons) ({ \
unsigned int req = (_r)->sring->req_prod - cons; \
unsigned int rsp = RING_SIZE(_r) - \
(cons - (_r)->rsp_prod_pvt); \
req < rsp ? req : rsp; \
})
#define virt_to_mfn(x) (vtophys(x) >> PAGE_SHIFT)
#define virt_to_offset(x) ((x) & (PAGE_SIZE - 1))
/**
* Predefined array type of grant table copy descriptors. Used to pass around
* statically allocated memory structures.
*/
typedef struct gnttab_copy gnttab_copy_table[GNTTAB_LEN];
/*--------------------------- Forward Declarations ---------------------------*/
struct xnb_softc;
struct xnb_pkt;
static void xnb_attach_failed(struct xnb_softc *xnb,
int err, const char *fmt, ...)
__printflike(3,4);
static int xnb_shutdown(struct xnb_softc *xnb);
static int create_netdev(device_t dev);
static int xnb_detach(device_t dev);
static int xnb_ifmedia_upd(struct ifnet *ifp);
static void xnb_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr);
static void xnb_intr(void *arg);
static int xnb_send(netif_rx_back_ring_t *rxb, domid_t otherend,
const struct mbuf *mbufc, gnttab_copy_table gnttab);
static int xnb_recv(netif_tx_back_ring_t *txb, domid_t otherend,
struct mbuf **mbufc, struct ifnet *ifnet,
gnttab_copy_table gnttab);
static int xnb_ring2pkt(struct xnb_pkt *pkt,
const netif_tx_back_ring_t *tx_ring,
RING_IDX start);
static void xnb_txpkt2rsp(const struct xnb_pkt *pkt,
netif_tx_back_ring_t *ring, int error);
static struct mbuf *xnb_pkt2mbufc(const struct xnb_pkt *pkt, struct ifnet *ifp);
static int xnb_txpkt2gnttab(const struct xnb_pkt *pkt,
struct mbuf *mbufc,
gnttab_copy_table gnttab,
const netif_tx_back_ring_t *txb,
domid_t otherend_id);
static void xnb_update_mbufc(struct mbuf *mbufc,
const gnttab_copy_table gnttab, int n_entries);
static int xnb_mbufc2pkt(const struct mbuf *mbufc,
struct xnb_pkt *pkt,
RING_IDX start, int space);
static int xnb_rxpkt2gnttab(const struct xnb_pkt *pkt,
const struct mbuf *mbufc,
gnttab_copy_table gnttab,
const netif_rx_back_ring_t *rxb,
domid_t otherend_id);
static int xnb_rxpkt2rsp(const struct xnb_pkt *pkt,
const gnttab_copy_table gnttab, int n_entries,
netif_rx_back_ring_t *ring);
static void xnb_stop(struct xnb_softc*);
static int xnb_ioctl(struct ifnet*, u_long, caddr_t);
static void xnb_start_locked(struct ifnet*);
static void xnb_start(struct ifnet*);
static void xnb_ifinit_locked(struct xnb_softc*);
static void xnb_ifinit(void*);
#ifdef XNB_DEBUG
static int xnb_unit_test_main(SYSCTL_HANDLER_ARGS);
static int xnb_dump_rings(SYSCTL_HANDLER_ARGS);
#endif
#if defined(INET) || defined(INET6)
static void xnb_add_mbuf_cksum(struct mbuf *mbufc);
#endif
/*------------------------------ Data Structures -----------------------------*/
/**
* Representation of a xennet packet. Simplified version of a packet as
* stored in the Xen tx ring. Applicable to both RX and TX packets
*/
struct xnb_pkt{
/**
* Array index of the first data-bearing (eg, not extra info) entry
* for this packet
*/
RING_IDX car;
/**
* Array index of the second data-bearing entry for this packet.
* Invalid if the packet has only one data-bearing entry. If the
* packet has more than two data-bearing entries, then the second
* through the last will be sequential modulo the ring size
*/
RING_IDX cdr;
/**
* Optional extra info. Only valid if flags contains
* NETTXF_extra_info. Note that extra.type will always be
* XEN_NETIF_EXTRA_TYPE_GSO. Currently, no known netfront or netback
* driver will ever set XEN_NETIF_EXTRA_TYPE_MCAST_*
*/
netif_extra_info_t extra;
/** Size of entire packet in bytes. */
uint16_t size;
/** The size of the first entry's data in bytes */
uint16_t car_size;
/**
* Either NETTXF_ or NETRXF_ flags. Note that the flag values are
* not the same for TX and RX packets
*/
uint16_t flags;
/**
* The number of valid data-bearing entries (either netif_tx_request's
* or netif_rx_response's) in the packet. If this is 0, it means the
* entire packet is invalid.
*/
uint16_t list_len;
/** There was an error processing the packet */
uint8_t error;
};
/** xnb_pkt method: initialize it */
static inline void
xnb_pkt_initialize(struct xnb_pkt *pxnb)
{
bzero(pxnb, sizeof(*pxnb));
}
/** xnb_pkt method: mark the packet as valid */
static inline void
xnb_pkt_validate(struct xnb_pkt *pxnb)
{
pxnb->error = 0;
};
/** xnb_pkt method: mark the packet as invalid */
static inline void
xnb_pkt_invalidate(struct xnb_pkt *pxnb)
{
pxnb->error = 1;
};
/** xnb_pkt method: Check whether the packet is valid */
static inline int
xnb_pkt_is_valid(const struct xnb_pkt *pxnb)
{
return (! pxnb->error);
}
#ifdef XNB_DEBUG
/** xnb_pkt method: print the packet's contents in human-readable format*/
static void __unused
xnb_dump_pkt(const struct xnb_pkt *pkt) {
if (pkt == NULL) {
DPRINTF("Was passed a null pointer.\n");
return;
}
DPRINTF("pkt address= %p\n", pkt);
DPRINTF("pkt->size=%d\n", pkt->size);
DPRINTF("pkt->car_size=%d\n", pkt->car_size);
DPRINTF("pkt->flags=0x%04x\n", pkt->flags);
DPRINTF("pkt->list_len=%d\n", pkt->list_len);
/* DPRINTF("pkt->extra"); TODO */
DPRINTF("pkt->car=%d\n", pkt->car);
DPRINTF("pkt->cdr=%d\n", pkt->cdr);
DPRINTF("pkt->error=%d\n", pkt->error);
}
#endif /* XNB_DEBUG */
static void
xnb_dump_txreq(RING_IDX idx, const struct netif_tx_request *txreq)
{
if (txreq != NULL) {
DPRINTF("netif_tx_request index =%u\n", idx);
DPRINTF("netif_tx_request.gref =%u\n", txreq->gref);
DPRINTF("netif_tx_request.offset=%hu\n", txreq->offset);
DPRINTF("netif_tx_request.flags =%hu\n", txreq->flags);
DPRINTF("netif_tx_request.id =%hu\n", txreq->id);
DPRINTF("netif_tx_request.size =%hu\n", txreq->size);
}
}
/**
* \brief Configuration data for a shared memory request ring
* used to communicate with the front-end client of this
* this driver.
*/
struct xnb_ring_config {
/**
* Runtime structures for ring access. Unfortunately, TX and RX rings
* use different data structures, and that cannot be changed since it
* is part of the interdomain protocol.
*/
union{
netif_rx_back_ring_t rx_ring;
netif_tx_back_ring_t tx_ring;
} back_ring;
/**
* The device bus address returned by the hypervisor when
* mapping the ring and required to unmap it when a connection
* is torn down.
*/
uint64_t bus_addr;
/** The pseudo-physical address where ring memory is mapped.*/
uint64_t gnt_addr;
/** KVA address where ring memory is mapped. */
vm_offset_t va;
/**
* Grant table handles, one per-ring page, returned by the
* hyperpervisor upon mapping of the ring and required to
* unmap it when a connection is torn down.
*/
grant_handle_t handle;
/** The number of ring pages mapped for the current connection. */
unsigned ring_pages;
/**
* The grant references, one per-ring page, supplied by the
* front-end, allowing us to reference the ring pages in the
* front-end's domain and to map these pages into our own domain.
*/
grant_ref_t ring_ref;
};
/**
* Per-instance connection state flags.
*/
typedef enum
{
/** Communication with the front-end has been established. */
XNBF_RING_CONNECTED = 0x01,
/**
* Front-end requests exist in the ring and are waiting for
* xnb_xen_req objects to free up.
*/
XNBF_RESOURCE_SHORTAGE = 0x02,
/** Connection teardown has started. */
XNBF_SHUTDOWN = 0x04,
/** A thread is already performing shutdown processing. */
XNBF_IN_SHUTDOWN = 0x08
} xnb_flag_t;
/**
* Types of rings. Used for array indices and to identify a ring's control
* data structure type
*/
typedef enum{
XNB_RING_TYPE_TX = 0, /* ID of TX rings, used for array indices */
XNB_RING_TYPE_RX = 1, /* ID of RX rings, used for array indices */
XNB_NUM_RING_TYPES
} xnb_ring_type_t;
/**
* Per-instance configuration data.
*/
struct xnb_softc {
/** NewBus device corresponding to this instance. */
device_t dev;
/* Media related fields */
/** Generic network media state */
struct ifmedia sc_media;
/** Media carrier info */
struct ifnet *xnb_ifp;
/** Our own private carrier state */
unsigned carrier;
/** Device MAC Address */
uint8_t mac[ETHER_ADDR_LEN];
/* Xen related fields */
/**
* \brief The netif protocol abi in effect.
*
* There are situations where the back and front ends can
* have a different, native abi (e.g. intel x86_64 and
* 32bit x86 domains on the same machine). The back-end
* always accommodates the front-end's native abi. That
* value is pulled from the XenStore and recorded here.
*/
int abi;
/**
* Name of the bridge to which this VIF is connected, if any
* This field is dynamically allocated by xenbus and must be free()ed
* when no longer needed
*/
char *bridge;
/** The interrupt driven even channel used to signal ring events. */
evtchn_port_t evtchn;
/** Xen device handle.*/
long handle;
/** Handle to the communication ring event channel. */
xen_intr_handle_t xen_intr_handle;
/**
* \brief Cached value of the front-end's domain id.
*
* This value is used at once for each mapped page in
* a transaction. We cache it to avoid incuring the
* cost of an ivar access every time this is needed.
*/
domid_t otherend_id;
/**
* Undocumented frontend feature. Has something to do with
* scatter/gather IO
*/
uint8_t can_sg;
/** Undocumented frontend feature */
uint8_t gso;
/** Undocumented frontend feature */
uint8_t gso_prefix;
/** Can checksum TCP/UDP over IPv4 */
uint8_t ip_csum;
/* Implementation related fields */
/**
* Preallocated grant table copy descriptor for RX operations.
* Access must be protected by rx_lock
*/
gnttab_copy_table rx_gnttab;
/**
* Preallocated grant table copy descriptor for TX operations.
* Access must be protected by tx_lock
*/
gnttab_copy_table tx_gnttab;
/**
* Resource representing allocated physical address space
* associated with our per-instance kva region.
*/
struct resource *pseudo_phys_res;
/** Resource id for allocated physical address space. */
int pseudo_phys_res_id;
/** Ring mapping and interrupt configuration data. */
struct xnb_ring_config ring_configs[XNB_NUM_RING_TYPES];
/**
* Global pool of kva used for mapping remote domain ring
* and I/O transaction data.
*/
vm_offset_t kva;
/** Pseudo-physical address corresponding to kva. */
uint64_t gnt_base_addr;
/** Various configuration and state bit flags. */
xnb_flag_t flags;
/** Mutex protecting per-instance data in the receive path. */
struct mtx rx_lock;
/** Mutex protecting per-instance data in the softc structure. */
struct mtx sc_lock;
/** Mutex protecting per-instance data in the transmit path. */
struct mtx tx_lock;
/** The size of the global kva pool. */
int kva_size;
/** Name of the interface */
char if_name[IFNAMSIZ];
};
/*---------------------------- Debugging functions ---------------------------*/
#ifdef XNB_DEBUG
static void __unused
xnb_dump_gnttab_copy(const struct gnttab_copy *entry)
{
if (entry == NULL) {
printf("NULL grant table pointer\n");
return;
}
if (entry->flags & GNTCOPY_dest_gref)
printf("gnttab dest ref=\t%u\n", entry->dest.u.ref);
else
printf("gnttab dest gmfn=\t%"PRI_xen_pfn"\n",
entry->dest.u.gmfn);
printf("gnttab dest offset=\t%hu\n", entry->dest.offset);
printf("gnttab dest domid=\t%hu\n", entry->dest.domid);
if (entry->flags & GNTCOPY_source_gref)
printf("gnttab source ref=\t%u\n", entry->source.u.ref);
else
printf("gnttab source gmfn=\t%"PRI_xen_pfn"\n",
entry->source.u.gmfn);
printf("gnttab source offset=\t%hu\n", entry->source.offset);
printf("gnttab source domid=\t%hu\n", entry->source.domid);
printf("gnttab len=\t%hu\n", entry->len);
printf("gnttab flags=\t%hu\n", entry->flags);
printf("gnttab status=\t%hd\n", entry->status);
}
static int
xnb_dump_rings(SYSCTL_HANDLER_ARGS)
{
static char results[720];
struct xnb_softc const* xnb = (struct xnb_softc*)arg1;
netif_rx_back_ring_t const* rxb =
&xnb->ring_configs[XNB_RING_TYPE_RX].back_ring.rx_ring;
netif_tx_back_ring_t const* txb =
&xnb->ring_configs[XNB_RING_TYPE_TX].back_ring.tx_ring;
/* empty the result strings */
results[0] = 0;
if ( !txb || !txb->sring || !rxb || !rxb->sring )
return (SYSCTL_OUT(req, results, strnlen(results, 720)));
snprintf(results, 720,
"\n\t%35s %18s\n" /* TX, RX */
"\t%16s %18d %18d\n" /* req_cons */
"\t%16s %18d %18d\n" /* nr_ents */
"\t%16s %18d %18d\n" /* rsp_prod_pvt */
"\t%16s %18p %18p\n" /* sring */
"\t%16s %18d %18d\n" /* req_prod */
"\t%16s %18d %18d\n" /* req_event */
"\t%16s %18d %18d\n" /* rsp_prod */
"\t%16s %18d %18d\n", /* rsp_event */
"TX", "RX",
"req_cons", txb->req_cons, rxb->req_cons,
"nr_ents", txb->nr_ents, rxb->nr_ents,
"rsp_prod_pvt", txb->rsp_prod_pvt, rxb->rsp_prod_pvt,
"sring", txb->sring, rxb->sring,
"sring->req_prod", txb->sring->req_prod, rxb->sring->req_prod,
"sring->req_event", txb->sring->req_event, rxb->sring->req_event,
"sring->rsp_prod", txb->sring->rsp_prod, rxb->sring->rsp_prod,
"sring->rsp_event", txb->sring->rsp_event, rxb->sring->rsp_event);
return (SYSCTL_OUT(req, results, strnlen(results, 720)));
}
static void __unused
xnb_dump_mbuf(const struct mbuf *m)
{
int len;
uint8_t *d;
if (m == NULL)
return;
printf("xnb_dump_mbuf:\n");
if (m->m_flags & M_PKTHDR) {
printf(" flowid=%10d, csum_flags=%#8x, csum_data=%#8x, "
"tso_segsz=%5hd\n",
m->m_pkthdr.flowid, (int)m->m_pkthdr.csum_flags,
m->m_pkthdr.csum_data, m->m_pkthdr.tso_segsz);
printf(" rcvif=%16p, len=%19d\n",
m->m_pkthdr.rcvif, m->m_pkthdr.len);
}
printf(" m_next=%16p, m_nextpk=%16p, m_data=%16p\n",
m->m_next, m->m_nextpkt, m->m_data);
printf(" m_len=%17d, m_flags=%#15x, m_type=%18u\n",
m->m_len, m->m_flags, m->m_type);
len = m->m_len;
d = mtod(m, uint8_t*);
while (len > 0) {
int i;
printf(" ");
for (i = 0; (i < 16) && (len > 0); i++, len--) {
printf("%02hhx ", *(d++));
}
printf("\n");
}
}
#endif /* XNB_DEBUG */
/*------------------------ Inter-Domain Communication ------------------------*/
/**
* Free dynamically allocated KVA or pseudo-physical address allocations.
*
* \param xnb Per-instance xnb configuration structure.
*/
static void
xnb_free_communication_mem(struct xnb_softc *xnb)
{
if (xnb->kva != 0) {
if (xnb->pseudo_phys_res != NULL) {
xenmem_free(xnb->dev, xnb->pseudo_phys_res_id,
xnb->pseudo_phys_res);
xnb->pseudo_phys_res = NULL;
}
}
xnb->kva = 0;
xnb->gnt_base_addr = 0;
}
/**
* Cleanup all inter-domain communication mechanisms.
*
* \param xnb Per-instance xnb configuration structure.
*/
static int
xnb_disconnect(struct xnb_softc *xnb)
{
struct gnttab_unmap_grant_ref gnts[XNB_NUM_RING_TYPES];
int error __diagused;
int i;
if (xnb->xen_intr_handle != NULL)
xen_intr_unbind(&xnb->xen_intr_handle);
/*
* We may still have another thread currently processing requests. We
* must acquire the rx and tx locks to make sure those threads are done,
* but we can release those locks as soon as we acquire them, because no
* more interrupts will be arriving.
*/
mtx_lock(&xnb->tx_lock);
mtx_unlock(&xnb->tx_lock);
mtx_lock(&xnb->rx_lock);
mtx_unlock(&xnb->rx_lock);
mtx_lock(&xnb->sc_lock);
/* Free malloc'd softc member variables */
if (xnb->bridge != NULL) {
free(xnb->bridge, M_XENSTORE);
xnb->bridge = NULL;
}
/* All request processing has stopped, so unmap the rings */
for (i=0; i < XNB_NUM_RING_TYPES; i++) {
gnts[i].host_addr = xnb->ring_configs[i].gnt_addr;
gnts[i].dev_bus_addr = xnb->ring_configs[i].bus_addr;
gnts[i].handle = xnb->ring_configs[i].handle;
}
error = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, gnts,
XNB_NUM_RING_TYPES);
KASSERT(error == 0, ("Grant table unmap op failed (%d)", error));
xnb_free_communication_mem(xnb);
/*
* Zero the ring config structs because the pointers, handles, and
* grant refs contained therein are no longer valid.
*/
bzero(&xnb->ring_configs[XNB_RING_TYPE_TX],
sizeof(struct xnb_ring_config));
bzero(&xnb->ring_configs[XNB_RING_TYPE_RX],
sizeof(struct xnb_ring_config));
xnb->flags &= ~XNBF_RING_CONNECTED;
mtx_unlock(&xnb->sc_lock);
return (0);
}
/**
* Map a single shared memory ring into domain local address space and
* initialize its control structure
*
* \param xnb Per-instance xnb configuration structure
* \param ring_type Array index of this ring in the xnb's array of rings
* \return An errno
*/
static int
xnb_connect_ring(struct xnb_softc *xnb, xnb_ring_type_t ring_type)
{
struct gnttab_map_grant_ref gnt;
struct xnb_ring_config *ring = &xnb->ring_configs[ring_type];
int error;
/* TX ring type = 0, RX =1 */
ring->va = xnb->kva + ring_type * PAGE_SIZE;
ring->gnt_addr = xnb->gnt_base_addr + ring_type * PAGE_SIZE;
gnt.host_addr = ring->gnt_addr;
gnt.flags = GNTMAP_host_map;
gnt.ref = ring->ring_ref;
gnt.dom = xnb->otherend_id;
error = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &gnt, 1);
if (error != 0)
panic("netback: Ring page grant table op failed (%d)", error);
if (gnt.status != 0) {
ring->va = 0;
error = EACCES;
xenbus_dev_fatal(xnb->dev, error,
"Ring shared page mapping failed. "
"Status %d.", gnt.status);
} else {
ring->handle = gnt.handle;
ring->bus_addr = gnt.dev_bus_addr;
if (ring_type == XNB_RING_TYPE_TX) {
BACK_RING_INIT(&ring->back_ring.tx_ring,
(netif_tx_sring_t*)ring->va,
ring->ring_pages * PAGE_SIZE);
} else if (ring_type == XNB_RING_TYPE_RX) {
BACK_RING_INIT(&ring->back_ring.rx_ring,
(netif_rx_sring_t*)ring->va,
ring->ring_pages * PAGE_SIZE);
} else {
xenbus_dev_fatal(xnb->dev, error,
"Unknown ring type %d", ring_type);
}
}
return error;
}
/**
* Setup the shared memory rings and bind an interrupt to the event channel
* used to notify us of ring changes.
*
* \param xnb Per-instance xnb configuration structure.
*/
static int
xnb_connect_comms(struct xnb_softc *xnb)
{
int error;
xnb_ring_type_t i;
if ((xnb->flags & XNBF_RING_CONNECTED) != 0)
return (0);
/*
* Kva for our rings are at the tail of the region of kva allocated
* by xnb_alloc_communication_mem().
*/
for (i=0; i < XNB_NUM_RING_TYPES; i++) {
error = xnb_connect_ring(xnb, i);
if (error != 0)
return error;
}
xnb->flags |= XNBF_RING_CONNECTED;
error = xen_intr_bind_remote_port(xnb->dev,
xnb->otherend_id,
xnb->evtchn,
/*filter*/NULL,
xnb_intr, /*arg*/xnb,
INTR_TYPE_NET | INTR_MPSAFE,
&xnb->xen_intr_handle);
if (error != 0) {
(void)xnb_disconnect(xnb);
xenbus_dev_fatal(xnb->dev, error, "binding event channel");
return (error);
}
DPRINTF("rings connected!\n");
return (0);
}
/**
* Size KVA and pseudo-physical address allocations based on negotiated
* values for the size and number of I/O requests, and the size of our
* communication ring.
*
* \param xnb Per-instance xnb configuration structure.
*
* These address spaces are used to dynamically map pages in the
* front-end's domain into our own.
*/
static int
xnb_alloc_communication_mem(struct xnb_softc *xnb)
{
xnb_ring_type_t i;
xnb->kva_size = 0;
for (i=0; i < XNB_NUM_RING_TYPES; i++) {
xnb->kva_size += xnb->ring_configs[i].ring_pages * PAGE_SIZE;
}
/*
* Reserve a range of pseudo physical memory that we can map
* into kva. These pages will only be backed by machine
* pages ("real memory") during the lifetime of front-end requests
* via grant table operations. We will map the netif tx and rx rings
* into this space.
*/
xnb->pseudo_phys_res_id = 0;
xnb->pseudo_phys_res = xenmem_alloc(xnb->dev, &xnb->pseudo_phys_res_id,
xnb->kva_size);
if (xnb->pseudo_phys_res == NULL) {
xnb->kva = 0;
return (ENOMEM);
}
xnb->kva = (vm_offset_t)rman_get_virtual(xnb->pseudo_phys_res);
xnb->gnt_base_addr = rman_get_start(xnb->pseudo_phys_res);
return (0);
}
/**
* Collect information from the XenStore related to our device and its frontend
*
* \param xnb Per-instance xnb configuration structure.
*/
static int
xnb_collect_xenstore_info(struct xnb_softc *xnb)
{
/**
* \todo Linux collects the following info. We should collect most
* of this, too:
* "feature-rx-notify"
*/
const char *otherend_path;
const char *our_path;
int err;
unsigned int rx_copy, bridge_len;
uint8_t no_csum_offload;
otherend_path = xenbus_get_otherend_path(xnb->dev);
our_path = xenbus_get_node(xnb->dev);
/* Collect the critical communication parameters */
err = xs_gather(XST_NIL, otherend_path,
"tx-ring-ref", "%l" PRIu32,
&xnb->ring_configs[XNB_RING_TYPE_TX].ring_ref,
"rx-ring-ref", "%l" PRIu32,
&xnb->ring_configs[XNB_RING_TYPE_RX].ring_ref,
"event-channel", "%" PRIu32, &xnb->evtchn,
NULL);
if (err != 0) {
xenbus_dev_fatal(xnb->dev, err,
"Unable to retrieve ring information from "
"frontend %s. Unable to connect.",
otherend_path);
return (err);
}
/* Collect the handle from xenstore */
err = xs_scanf(XST_NIL, our_path, "handle", NULL, "%li", &xnb->handle);
if (err != 0) {
xenbus_dev_fatal(xnb->dev, err,
"Error reading handle from frontend %s. "
"Unable to connect.", otherend_path);
}
/*
* Collect the bridgename, if any. We do not need bridge_len; we just
* throw it away
*/
err = xs_read(XST_NIL, our_path, "bridge", &bridge_len,
(void**)&xnb->bridge);
if (err != 0)
xnb->bridge = NULL;
/*
* Does the frontend request that we use rx copy? If not, return an
* error because this driver only supports rx copy.
*/
err = xs_scanf(XST_NIL, otherend_path, "request-rx-copy", NULL,
"%" PRIu32, &rx_copy);
if (err == ENOENT) {
err = 0;
rx_copy = 0;
}
if (err < 0) {
xenbus_dev_fatal(xnb->dev, err, "reading %s/request-rx-copy",
otherend_path);
return err;
}
/**
* \todo: figure out the exact meaning of this feature, and when
* the frontend will set it to true. It should be set to true
* at some point
*/
/* if (!rx_copy)*/
/* return EOPNOTSUPP;*/
/** \todo Collect the rx notify feature */
/* Collect the feature-sg. */
if (xs_scanf(XST_NIL, otherend_path, "feature-sg", NULL,
"%hhu", &xnb->can_sg) < 0)
xnb->can_sg = 0;
/* Collect remaining frontend features */
if (xs_scanf(XST_NIL, otherend_path, "feature-gso-tcpv4", NULL,
"%hhu", &xnb->gso) < 0)
xnb->gso = 0;
if (xs_scanf(XST_NIL, otherend_path, "feature-gso-tcpv4-prefix", NULL,
"%hhu", &xnb->gso_prefix) < 0)
xnb->gso_prefix = 0;
if (xs_scanf(XST_NIL, otherend_path, "feature-no-csum-offload", NULL,
"%hhu", &no_csum_offload) < 0)
no_csum_offload = 0;
xnb->ip_csum = (no_csum_offload == 0);
return (0);
}
/**
* Supply information about the physical device to the frontend
* via XenBus.
*
* \param xnb Per-instance xnb configuration structure.
*/
static int
xnb_publish_backend_info(struct xnb_softc *xnb)
{
struct xs_transaction xst;
const char *our_path;
int error;
our_path = xenbus_get_node(xnb->dev);
do {
error = xs_transaction_start(&xst);
if (error != 0) {
xenbus_dev_fatal(xnb->dev, error,
"Error publishing backend info "
"(start transaction)");
break;
}
error = xs_printf(xst, our_path, "feature-sg",
"%d", XNB_SG);
if (error != 0)
break;
error = xs_printf(xst, our_path, "feature-gso-tcpv4",
"%d", XNB_GSO_TCPV4);
if (error != 0)
break;
error = xs_printf(xst, our_path, "feature-rx-copy",
"%d", XNB_RX_COPY);
if (error != 0)
break;
error = xs_printf(xst, our_path, "feature-rx-flip",
"%d", XNB_RX_FLIP);
if (error != 0)
break;
error = xs_transaction_end(xst, 0);
if (error != 0 && error != EAGAIN) {
xenbus_dev_fatal(xnb->dev, error, "ending transaction");
break;
}
} while (error == EAGAIN);
return (error);
}
/**
* Connect to our netfront peer now that it has completed publishing
* its configuration into the XenStore.
*
* \param xnb Per-instance xnb configuration structure.
*/
static void
xnb_connect(struct xnb_softc *xnb)
{
int error;
if (xenbus_get_state(xnb->dev) == XenbusStateConnected)
return;
if (xnb_collect_xenstore_info(xnb) != 0)
return;
xnb->flags &= ~XNBF_SHUTDOWN;
/* Read front end configuration. */
/* Allocate resources whose size depends on front-end configuration. */
error = xnb_alloc_communication_mem(xnb);
if (error != 0) {
xenbus_dev_fatal(xnb->dev, error,
"Unable to allocate communication memory");
return;
}
/*
* Connect communication channel.
*/
error = xnb_connect_comms(xnb);
if (error != 0) {
/* Specific errors are reported by xnb_connect_comms(). */
return;
}
xnb->carrier = 1;
/* Ready for I/O. */
xenbus_set_state(xnb->dev, XenbusStateConnected);
}
/*-------------------------- Device Teardown Support -------------------------*/
/**
* Perform device shutdown functions.
*
* \param xnb Per-instance xnb configuration structure.
*
* Mark this instance as shutting down, wait for any active requests
* to drain, disconnect from the front-end, and notify any waiters (e.g.
* a thread invoking our detach method) that detach can now proceed.
*/
static int
xnb_shutdown(struct xnb_softc *xnb)
{
/*
* Due to the need to drop our mutex during some
* xenbus operations, it is possible for two threads
* to attempt to close out shutdown processing at
* the same time. Tell the caller that hits this
* race to try back later.
*/
if ((xnb->flags & XNBF_IN_SHUTDOWN) != 0)
return (EAGAIN);
xnb->flags |= XNBF_SHUTDOWN;
xnb->flags |= XNBF_IN_SHUTDOWN;
mtx_unlock(&xnb->sc_lock);
/* Free the network interface */
xnb->carrier = 0;
if (xnb->xnb_ifp != NULL) {
ether_ifdetach(xnb->xnb_ifp);
if_free(xnb->xnb_ifp);
xnb->xnb_ifp = NULL;
}
xnb_disconnect(xnb);
if (xenbus_get_state(xnb->dev) < XenbusStateClosing)
xenbus_set_state(xnb->dev, XenbusStateClosing);
mtx_lock(&xnb->sc_lock);
xnb->flags &= ~XNBF_IN_SHUTDOWN;
/* Indicate to xnb_detach() that is it safe to proceed. */
wakeup(xnb);
return (0);
}
/**
* Report an attach time error to the console and Xen, and cleanup
* this instance by forcing immediate detach processing.
*
* \param xnb Per-instance xnb configuration structure.
* \param err Errno describing the error.
* \param fmt Printf style format and arguments
*/
static void
xnb_attach_failed(struct xnb_softc *xnb, int err, const char *fmt, ...)
{
va_list ap;
va_list ap_hotplug;
va_start(ap, fmt);
va_copy(ap_hotplug, ap);
xs_vprintf(XST_NIL, xenbus_get_node(xnb->dev),
"hotplug-error", fmt, ap_hotplug);
va_end(ap_hotplug);
(void)xs_printf(XST_NIL, xenbus_get_node(xnb->dev),
"hotplug-status", "error");
xenbus_dev_vfatal(xnb->dev, err, fmt, ap);
va_end(ap);
(void)xs_printf(XST_NIL, xenbus_get_node(xnb->dev), "online", "0");
xnb_detach(xnb->dev);
}
/*---------------------------- NewBus Entrypoints ----------------------------*/
/**
* Inspect a XenBus device and claim it if is of the appropriate type.
*
* \param dev NewBus device object representing a candidate XenBus device.
*
* \return 0 for success, errno codes for failure.
*/
static int
xnb_probe(device_t dev)
{
if (!strcmp(xenbus_get_type(dev), "vif")) {
DPRINTF("Claiming device %d, %s\n", device_get_unit(dev),
devclass_get_name(device_get_devclass(dev)));
device_set_desc(dev, "Backend Virtual Network Device");
device_quiet(dev);
return (0);
}
return (ENXIO);
}
/**
* Setup sysctl variables to control various Network Back parameters.
*
* \param xnb Xen Net Back softc.
*
*/
static void
xnb_setup_sysctl(struct xnb_softc *xnb)
{
struct sysctl_ctx_list *sysctl_ctx = NULL;
struct sysctl_oid *sysctl_tree = NULL;
sysctl_ctx = device_get_sysctl_ctx(xnb->dev);
if (sysctl_ctx == NULL)
return;
sysctl_tree = device_get_sysctl_tree(xnb->dev);
if (sysctl_tree == NULL)
return;
#ifdef XNB_DEBUG
SYSCTL_ADD_PROC(sysctl_ctx,
SYSCTL_CHILDREN(sysctl_tree),
OID_AUTO,
"unit_test_results",
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
xnb,
0,
xnb_unit_test_main,
"A",
"Results of builtin unit tests");
SYSCTL_ADD_PROC(sysctl_ctx,
SYSCTL_CHILDREN(sysctl_tree),
OID_AUTO,
"dump_rings",
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
xnb,
0,
xnb_dump_rings,
"A",
"Xennet Back Rings");
#endif /* XNB_DEBUG */
}
/**
* Create a network device.
* @param handle device handle
*/
int
create_netdev(device_t dev)
{
struct ifnet *ifp;
struct xnb_softc *xnb;
int err = 0;
uint32_t handle;
xnb = device_get_softc(dev);
mtx_init(&xnb->sc_lock, "xnb_softc", "xen netback softc lock", MTX_DEF);
mtx_init(&xnb->tx_lock, "xnb_tx", "xen netback tx lock", MTX_DEF);
mtx_init(&xnb->rx_lock, "xnb_rx", "xen netback rx lock", MTX_DEF);
xnb->dev = dev;
ifmedia_init(&xnb->sc_media, 0, xnb_ifmedia_upd, xnb_ifmedia_sts);
ifmedia_add(&xnb->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
ifmedia_set(&xnb->sc_media, IFM_ETHER|IFM_MANUAL);
/*
* Set the MAC address to a dummy value (00:00:00:00:00),
* if the MAC address of the host-facing interface is set
* to the same as the guest-facing one (the value found in
* xenstore), the bridge would stop delivering packets to
* us because it would see that the destination address of
* the packet is the same as the interface, and so the bridge
* would expect the packet has already been delivered locally
* (and just drop it).
*/
bzero(&xnb->mac[0], sizeof(xnb->mac));
/* The interface will be named using the following nomenclature:
*
* xnb<domid>.<handle>
*
* Where handle is the oder of the interface referred to the guest.
*/
err = xs_scanf(XST_NIL, xenbus_get_node(xnb->dev), "handle", NULL,
"%" PRIu32, &handle);
if (err != 0)
return (err);
snprintf(xnb->if_name, IFNAMSIZ, "xnb%" PRIu16 ".%" PRIu32,
xenbus_get_otherend_id(dev), handle);
if (err == 0) {
/* Set up ifnet structure */
ifp = xnb->xnb_ifp = if_alloc(IFT_ETHER);
ifp->if_softc = xnb;
if_initname(ifp, xnb->if_name, IF_DUNIT_NONE);
ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
ifp->if_ioctl = xnb_ioctl;
ifp->if_start = xnb_start;
ifp->if_init = xnb_ifinit;
ifp->if_mtu = ETHERMTU;
ifp->if_snd.ifq_maxlen = NET_RX_RING_SIZE - 1;
ifp->if_hwassist = XNB_CSUM_FEATURES;
ifp->if_capabilities = IFCAP_HWCSUM;
ifp->if_capenable = IFCAP_HWCSUM;
ether_ifattach(ifp, xnb->mac);
xnb->carrier = 0;
}
return err;
}
/**
* Attach to a XenBus device that has been claimed by our probe routine.
*
* \param dev NewBus device object representing this Xen Net Back instance.
*
* \return 0 for success, errno codes for failure.
*/
static int
xnb_attach(device_t dev)
{
struct xnb_softc *xnb;
int error;
xnb_ring_type_t i;
error = create_netdev(dev);
if (error != 0) {
xenbus_dev_fatal(dev, error, "creating netdev");
return (error);
}
DPRINTF("Attaching to %s\n", xenbus_get_node(dev));
/*
* Basic initialization.
* After this block it is safe to call xnb_detach()
* to clean up any allocated data for this instance.
*/
xnb = device_get_softc(dev);
xnb->otherend_id = xenbus_get_otherend_id(dev);
for (i=0; i < XNB_NUM_RING_TYPES; i++) {
xnb->ring_configs[i].ring_pages = 1;
}
/*
* Setup sysctl variables.
*/
xnb_setup_sysctl(xnb);
/* Update hot-plug status to satisfy xend. */
error = xs_printf(XST_NIL, xenbus_get_node(xnb->dev),
"hotplug-status", "connected");
if (error != 0) {
xnb_attach_failed(xnb, error, "writing %s/hotplug-status",
xenbus_get_node(xnb->dev));
return (error);
}
if ((error = xnb_publish_backend_info(xnb)) != 0) {
/*
* If we can't publish our data, we cannot participate
* in this connection, and waiting for a front-end state
* change will not help the situation.
*/
xnb_attach_failed(xnb, error,
"Publishing backend status for %s",
xenbus_get_node(xnb->dev));
return error;
}
/* Tell the front end that we are ready to connect. */
xenbus_set_state(dev, XenbusStateInitWait);
return (0);
}
/**
* Detach from a net back device instance.
*
* \param dev NewBus device object representing this Xen Net Back instance.
*
* \return 0 for success, errno codes for failure.
*
* \note A net back device may be detached at any time in its life-cycle,
* including part way through the attach process. For this reason,
* initialization order and the initialization state checks in this
* routine must be carefully coupled so that attach time failures
* are gracefully handled.
*/
static int
xnb_detach(device_t dev)
{
struct xnb_softc *xnb;
DPRINTF("\n");
xnb = device_get_softc(dev);
mtx_lock(&xnb->sc_lock);
while (xnb_shutdown(xnb) == EAGAIN) {
msleep(xnb, &xnb->sc_lock, /*wakeup prio unchanged*/0,
"xnb_shutdown", 0);
}
mtx_unlock(&xnb->sc_lock);
DPRINTF("\n");
mtx_destroy(&xnb->tx_lock);
mtx_destroy(&xnb->rx_lock);
mtx_destroy(&xnb->sc_lock);
return (0);
}
/**
* Prepare this net back device for suspension of this VM.
*
* \param dev NewBus device object representing this Xen net Back instance.
*
* \return 0 for success, errno codes for failure.
*/
static int
xnb_suspend(device_t dev)
{
return (0);
}
/**
* Perform any processing required to recover from a suspended state.
*
* \param dev NewBus device object representing this Xen Net Back instance.
*
* \return 0 for success, errno codes for failure.
*/
static int
xnb_resume(device_t dev)
{
return (0);
}
/**
* Handle state changes expressed via the XenStore by our front-end peer.
*
* \param dev NewBus device object representing this Xen
* Net Back instance.
* \param frontend_state The new state of the front-end.
*
* \return 0 for success, errno codes for failure.
*/
static void
xnb_frontend_changed(device_t dev, XenbusState frontend_state)
{
struct xnb_softc *xnb;
xnb = device_get_softc(dev);
DPRINTF("frontend_state=%s, xnb_state=%s\n",
xenbus_strstate(frontend_state),
xenbus_strstate(xenbus_get_state(xnb->dev)));
switch (frontend_state) {
case XenbusStateInitialising:
case XenbusStateInitialised:
break;
case XenbusStateConnected:
xnb_connect(xnb);
break;
case XenbusStateClosing:
case XenbusStateClosed:
mtx_lock(&xnb->sc_lock);
xnb_shutdown(xnb);
mtx_unlock(&xnb->sc_lock);
if (frontend_state == XenbusStateClosed)
xenbus_set_state(xnb->dev, XenbusStateClosed);
break;
default:
xenbus_dev_fatal(xnb->dev, EINVAL, "saw state %d at frontend",
frontend_state);
break;
}
}
/*---------------------------- Request Processing ----------------------------*/
/**
* Interrupt handler bound to the shared ring's event channel.
* Entry point for the xennet transmit path in netback
* Transfers packets from the Xen ring to the host's generic networking stack
*
* \param arg Callback argument registerd during event channel
* binding - the xnb_softc for this instance.
*/
static void
xnb_intr(void *arg)
{
struct xnb_softc *xnb;
struct ifnet *ifp;
netif_tx_back_ring_t *txb;
RING_IDX req_prod_local;
xnb = (struct xnb_softc *)arg;
ifp = xnb->xnb_ifp;
txb = &xnb->ring_configs[XNB_RING_TYPE_TX].back_ring.tx_ring;
mtx_lock(&xnb->tx_lock);
do {
int notify;
req_prod_local = txb->sring->req_prod;
xen_rmb();
for (;;) {
struct mbuf *mbufc;
int err;
err = xnb_recv(txb, xnb->otherend_id, &mbufc, ifp,
xnb->tx_gnttab);
if (err || (mbufc == NULL))
break;
/* Send the packet to the generic network stack */
(*xnb->xnb_ifp->if_input)(xnb->xnb_ifp, mbufc);
}
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(txb, notify);
if (notify != 0)
xen_intr_signal(xnb->xen_intr_handle);
txb->sring->req_event = txb->req_cons + 1;
xen_mb();
} while (txb->sring->req_prod != req_prod_local) ;
mtx_unlock(&xnb->tx_lock);
xnb_start(ifp);
}
/**
* Build a struct xnb_pkt based on netif_tx_request's from a netif tx ring.
* Will read exactly 0 or 1 packets from the ring; never a partial packet.
* \param[out] pkt The returned packet. If there is an error building
* the packet, pkt.list_len will be set to 0.
* \param[in] tx_ring Pointer to the Ring that is the input to this function
* \param[in] start The ring index of the first potential request
* \return The number of requests consumed to build this packet
*/
static int
xnb_ring2pkt(struct xnb_pkt *pkt, const netif_tx_back_ring_t *tx_ring,
RING_IDX start)
{
/*
* Outline:
* 1) Initialize pkt
* 2) Read the first request of the packet
* 3) Read the extras
* 4) Set cdr
* 5) Loop on the remainder of the packet
* 6) Finalize pkt (stuff like car_size and list_len)
*/
int idx = start;
int discard = 0; /* whether to discard the packet */
int more_data = 0; /* there are more request past the last one */
uint16_t cdr_size = 0; /* accumulated size of requests 2 through n */
xnb_pkt_initialize(pkt);
/* Read the first request */
if (RING_HAS_UNCONSUMED_REQUESTS_2(tx_ring, idx)) {
netif_tx_request_t *tx = RING_GET_REQUEST(tx_ring, idx);
pkt->size = tx->size;
pkt->flags = tx->flags & ~NETTXF_more_data;
more_data = tx->flags & NETTXF_more_data;
pkt->list_len++;
pkt->car = idx;
idx++;
}
/* Read the extra info */
if ((pkt->flags & NETTXF_extra_info) &&
RING_HAS_UNCONSUMED_REQUESTS_2(tx_ring, idx)) {
netif_extra_info_t *ext =
(netif_extra_info_t*) RING_GET_REQUEST(tx_ring, idx);
pkt->extra.type = ext->type;
switch (pkt->extra.type) {
case XEN_NETIF_EXTRA_TYPE_GSO:
pkt->extra.u.gso = ext->u.gso;
break;
default:
/*
* The reference Linux netfront driver will
* never set any other extra.type. So we don't
* know what to do with it. Let's print an
* error, then consume and discard the packet
*/
printf("xnb(%s:%d): Unknown extra info type %d."
" Discarding packet\n",
__func__, __LINE__, pkt->extra.type);
xnb_dump_txreq(start, RING_GET_REQUEST(tx_ring,
start));
xnb_dump_txreq(idx, RING_GET_REQUEST(tx_ring,
idx));
discard = 1;
break;
}
pkt->extra.flags = ext->flags;
if (ext->flags & XEN_NETIF_EXTRA_FLAG_MORE) {
/*
* The reference linux netfront driver never sets this
* flag (nor does any other known netfront). So we
* will discard the packet.
*/
printf("xnb(%s:%d): Request sets "
"XEN_NETIF_EXTRA_FLAG_MORE, but we can't handle "
"that\n", __func__, __LINE__);
xnb_dump_txreq(start, RING_GET_REQUEST(tx_ring, start));
xnb_dump_txreq(idx, RING_GET_REQUEST(tx_ring, idx));
discard = 1;
}
idx++;
}
/* Set cdr. If there is not more data, cdr is invalid */
pkt->cdr = idx;
/* Loop on remainder of packet */
while (more_data && RING_HAS_UNCONSUMED_REQUESTS_2(tx_ring, idx)) {
netif_tx_request_t *tx = RING_GET_REQUEST(tx_ring, idx);
pkt->list_len++;
cdr_size += tx->size;
if (tx->flags & ~NETTXF_more_data) {
/* There should be no other flags set at this point */
printf("xnb(%s:%d): Request sets unknown flags %d "
"after the 1st request in the packet.\n",
__func__, __LINE__, tx->flags);
xnb_dump_txreq(start, RING_GET_REQUEST(tx_ring, start));
xnb_dump_txreq(idx, RING_GET_REQUEST(tx_ring, idx));
}
more_data = tx->flags & NETTXF_more_data;
idx++;
}
/* Finalize packet */
if (more_data != 0) {
/* The ring ran out of requests before finishing the packet */
xnb_pkt_invalidate(pkt);
idx = start; /* tell caller that we consumed no requests */
} else {
/* Calculate car_size */
pkt->car_size = pkt->size - cdr_size;
}
if (discard != 0) {
xnb_pkt_invalidate(pkt);
}
return idx - start;
}
/**
* Respond to all the requests that constituted pkt. Builds the responses and
* writes them to the ring, but doesn't push them to the shared ring.
* \param[in] pkt the packet that needs a response
* \param[in] error true if there was an error handling the packet, such
* as in the hypervisor copy op or mbuf allocation
* \param[out] ring Responses go here
*/
static void
xnb_txpkt2rsp(const struct xnb_pkt *pkt, netif_tx_back_ring_t *ring,
int error)
{
/*
* Outline:
* 1) Respond to the first request
* 2) Respond to the extra info reques
* Loop through every remaining request in the packet, generating
* responses that copy those requests' ids and sets the status
* appropriately.
*/
netif_tx_request_t *tx;
netif_tx_response_t *rsp;
int i;
uint16_t status;
status = (xnb_pkt_is_valid(pkt) == 0) || error ?
NETIF_RSP_ERROR : NETIF_RSP_OKAY;
KASSERT((pkt->list_len == 0) || (ring->rsp_prod_pvt == pkt->car),
("Cannot respond to ring requests out of order"));
if (pkt->list_len >= 1) {
uint16_t id;
tx = RING_GET_REQUEST(ring, ring->rsp_prod_pvt);
id = tx->id;
rsp = RING_GET_RESPONSE(ring, ring->rsp_prod_pvt);
rsp->id = id;
rsp->status = status;
ring->rsp_prod_pvt++;
if (pkt->flags & NETRXF_extra_info) {
rsp = RING_GET_RESPONSE(ring, ring->rsp_prod_pvt);
rsp->status = NETIF_RSP_NULL;
ring->rsp_prod_pvt++;
}
}
for (i=0; i < pkt->list_len - 1; i++) {
uint16_t id;
tx = RING_GET_REQUEST(ring, ring->rsp_prod_pvt);
id = tx->id;
rsp = RING_GET_RESPONSE(ring, ring->rsp_prod_pvt);
rsp->id = id;
rsp->status = status;
ring->rsp_prod_pvt++;
}
}
/**
* Create an mbuf chain to represent a packet. Initializes all of the headers
* in the mbuf chain, but does not copy the data. The returned chain must be
* free()'d when no longer needed
* \param[in] pkt A packet to model the mbuf chain after
* \return A newly allocated mbuf chain, possibly with clusters attached.
* NULL on failure
*/
static struct mbuf*
xnb_pkt2mbufc(const struct xnb_pkt *pkt, struct ifnet *ifp)
{
/**
* \todo consider using a memory pool for mbufs instead of
* reallocating them for every packet
*/
/** \todo handle extra data */
struct mbuf *m;
m = m_getm(NULL, pkt->size, M_NOWAIT, MT_DATA);
if (m != NULL) {
m->m_pkthdr.rcvif = ifp;
if (pkt->flags & NETTXF_data_validated) {
/*
* We lie to the host OS and always tell it that the
* checksums are ok, because the packet is unlikely to
* get corrupted going across domains.
*/
m->m_pkthdr.csum_flags = (
CSUM_IP_CHECKED |
CSUM_IP_VALID |
CSUM_DATA_VALID |
CSUM_PSEUDO_HDR
);
m->m_pkthdr.csum_data = 0xffff;
}
}
return m;
}
/**
* Build a gnttab_copy table that can be used to copy data from a pkt
* to an mbufc. Does not actually perform the copy. Always uses gref's on
* the packet side.
* \param[in] pkt pkt's associated requests form the src for
* the copy operation
* \param[in] mbufc mbufc's storage forms the dest for the copy operation
* \param[out] gnttab Storage for the returned grant table
* \param[in] txb Pointer to the backend ring structure
* \param[in] otherend_id The domain ID of the other end of the copy
* \return The number of gnttab entries filled
*/
static int
xnb_txpkt2gnttab(const struct xnb_pkt *pkt, struct mbuf *mbufc,
gnttab_copy_table gnttab, const netif_tx_back_ring_t *txb,
domid_t otherend_id)
{
struct mbuf *mbuf = mbufc;/* current mbuf within the chain */
int gnt_idx = 0; /* index into grant table */
RING_IDX r_idx = pkt->car; /* index into tx ring buffer */
int r_ofs = 0; /* offset of next data within tx request's data area */
int m_ofs = 0; /* offset of next data within mbuf's data area */
/* size in bytes that still needs to be represented in the table */
uint16_t size_remaining = pkt->size;
while (size_remaining > 0) {
const netif_tx_request_t *txq = RING_GET_REQUEST(txb, r_idx);
const size_t mbuf_space = M_TRAILINGSPACE(mbuf) - m_ofs;
const size_t req_size =
r_idx == pkt->car ? pkt->car_size : txq->size;
const size_t pkt_space = req_size - r_ofs;
/*
* space is the largest amount of data that can be copied in the
* grant table's next entry
*/
const size_t space = MIN(pkt_space, mbuf_space);
/* TODO: handle this error condition without panicking */
KASSERT(gnt_idx < GNTTAB_LEN, ("Grant table is too short"));
gnttab[gnt_idx].source.u.ref = txq->gref;
gnttab[gnt_idx].source.domid = otherend_id;
gnttab[gnt_idx].source.offset = txq->offset + r_ofs;
gnttab[gnt_idx].dest.u.gmfn = virt_to_mfn(
mtod(mbuf, vm_offset_t) + m_ofs);
gnttab[gnt_idx].dest.offset = virt_to_offset(
mtod(mbuf, vm_offset_t) + m_ofs);
gnttab[gnt_idx].dest.domid = DOMID_SELF;
gnttab[gnt_idx].len = space;
gnttab[gnt_idx].flags = GNTCOPY_source_gref;
gnt_idx++;
r_ofs += space;
m_ofs += space;
size_remaining -= space;
if (req_size - r_ofs <= 0) {
/* Must move to the next tx request */
r_ofs = 0;
r_idx = (r_idx == pkt->car) ? pkt->cdr : r_idx + 1;
}
if (M_TRAILINGSPACE(mbuf) - m_ofs <= 0) {
/* Must move to the next mbuf */
m_ofs = 0;
mbuf = mbuf->m_next;
}
}
return gnt_idx;
}
/**
* Check the status of the grant copy operations, and update mbufs various
* non-data fields to reflect the data present.
* \param[in,out] mbufc mbuf chain to update. The chain must be valid and of
* the correct length, and data should already be present
* \param[in] gnttab A grant table for a just completed copy op
* \param[in] n_entries The number of valid entries in the grant table
*/
static void
xnb_update_mbufc(struct mbuf *mbufc, const gnttab_copy_table gnttab,
int n_entries)
{
struct mbuf *mbuf = mbufc;
int i;
size_t total_size = 0;
for (i = 0; i < n_entries; i++) {
KASSERT(gnttab[i].status == GNTST_okay,
("Some gnttab_copy entry had error status %hd\n",
gnttab[i].status));
mbuf->m_len += gnttab[i].len;
total_size += gnttab[i].len;
if (M_TRAILINGSPACE(mbuf) <= 0) {
mbuf = mbuf->m_next;
}
}
mbufc->m_pkthdr.len = total_size;
#if defined(INET) || defined(INET6)
xnb_add_mbuf_cksum(mbufc);
#endif
}
/**
* Dequeue at most one packet from the shared ring
* \param[in,out] txb Netif tx ring. A packet will be removed from it, and
* its private indices will be updated. But the indices
* will not be pushed to the shared ring.
* \param[in] ifnet Interface to which the packet will be sent
* \param[in] otherend Domain ID of the other end of the ring
* \param[out] mbufc The assembled mbuf chain, ready to send to the generic
* networking stack
* \param[in,out] gnttab Pointer to enough memory for a grant table. We make
* this a function parameter so that we will take less
* stack space.
* \return An error code
*/
static int
xnb_recv(netif_tx_back_ring_t *txb, domid_t otherend, struct mbuf **mbufc,
struct ifnet *ifnet, gnttab_copy_table gnttab)
{
struct xnb_pkt pkt;
/* number of tx requests consumed to build the last packet */
int num_consumed;
int nr_ents;
*mbufc = NULL;
num_consumed = xnb_ring2pkt(&pkt, txb, txb->req_cons);
if (num_consumed == 0)
return 0; /* Nothing to receive */
/* update statistics independent of errors */
if_inc_counter(ifnet, IFCOUNTER_IPACKETS, 1);
/*
* if we got here, then 1 or more requests was consumed, but the packet
* is not necessarily valid.
*/
if (xnb_pkt_is_valid(&pkt) == 0) {
/* got a garbage packet, respond and drop it */
xnb_txpkt2rsp(&pkt, txb, 1);
txb->req_cons += num_consumed;
DPRINTF("xnb_intr: garbage packet, num_consumed=%d\n",
num_consumed);
if_inc_counter(ifnet, IFCOUNTER_IERRORS, 1);
return EINVAL;
}
*mbufc = xnb_pkt2mbufc(&pkt, ifnet);
if (*mbufc == NULL) {
/*
* Couldn't allocate mbufs. Respond and drop the packet. Do
* not consume the requests
*/
xnb_txpkt2rsp(&pkt, txb, 1);
DPRINTF("xnb_intr: Couldn't allocate mbufs, num_consumed=%d\n",
num_consumed);
if_inc_counter(ifnet, IFCOUNTER_IQDROPS, 1);
return ENOMEM;
}
nr_ents = xnb_txpkt2gnttab(&pkt, *mbufc, gnttab, txb, otherend);
if (nr_ents > 0) {
int __unused hv_ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
gnttab, nr_ents);
KASSERT(hv_ret == 0,
("HYPERVISOR_grant_table_op returned %d\n", hv_ret));
xnb_update_mbufc(*mbufc, gnttab, nr_ents);
}
xnb_txpkt2rsp(&pkt, txb, 0);
txb->req_cons += num_consumed;
return 0;
}
/**
* Create an xnb_pkt based on the contents of an mbuf chain.
* \param[in] mbufc mbuf chain to transform into a packet
* \param[out] pkt Storage for the newly generated xnb_pkt
* \param[in] start The ring index of the first available slot in the rx
* ring
* \param[in] space The number of free slots in the rx ring
* \retval 0 Success
* \retval EINVAL mbufc was corrupt or not convertible into a pkt
* \retval EAGAIN There was not enough space in the ring to queue the
* packet
*/
static int
xnb_mbufc2pkt(const struct mbuf *mbufc, struct xnb_pkt *pkt,
RING_IDX start, int space)
{
int retval = 0;
if ((mbufc == NULL) ||
( (mbufc->m_flags & M_PKTHDR) == 0) ||
(mbufc->m_pkthdr.len == 0)) {
xnb_pkt_invalidate(pkt);
retval = EINVAL;
} else {
int slots_required;
xnb_pkt_validate(pkt);
pkt->flags = 0;
pkt->size = mbufc->m_pkthdr.len;
pkt->car = start;
pkt->car_size = mbufc->m_len;
if (mbufc->m_pkthdr.csum_flags & CSUM_TSO) {
pkt->flags |= NETRXF_extra_info;
pkt->extra.u.gso.size = mbufc->m_pkthdr.tso_segsz;
pkt->extra.u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
pkt->extra.u.gso.pad = 0;
pkt->extra.u.gso.features = 0;
pkt->extra.type = XEN_NETIF_EXTRA_TYPE_GSO;
pkt->extra.flags = 0;
pkt->cdr = start + 2;
} else {
pkt->cdr = start + 1;
}
if (mbufc->m_pkthdr.csum_flags & (CSUM_TSO | CSUM_DELAY_DATA)) {
pkt->flags |=
(NETRXF_csum_blank | NETRXF_data_validated);
}
/*
* Each ring response can have up to PAGE_SIZE of data.
* Assume that we can defragment the mbuf chain efficiently
* into responses so that each response but the last uses all
* PAGE_SIZE bytes.
*/
pkt->list_len = howmany(pkt->size, PAGE_SIZE);
if (pkt->list_len > 1) {
pkt->flags |= NETRXF_more_data;
}
slots_required = pkt->list_len +
(pkt->flags & NETRXF_extra_info ? 1 : 0);
if (slots_required > space) {
xnb_pkt_invalidate(pkt);
retval = EAGAIN;
}
}
return retval;
}
/**
* Build a gnttab_copy table that can be used to copy data from an mbuf chain
* to the frontend's shared buffers. Does not actually perform the copy.
* Always uses gref's on the other end's side.
* \param[in] pkt pkt's associated responses form the dest for the copy
* operatoin
* \param[in] mbufc The source for the copy operation
* \param[out] gnttab Storage for the returned grant table
* \param[in] rxb Pointer to the backend ring structure
* \param[in] otherend_id The domain ID of the other end of the copy
* \return The number of gnttab entries filled
*/
static int
xnb_rxpkt2gnttab(const struct xnb_pkt *pkt, const struct mbuf *mbufc,
gnttab_copy_table gnttab, const netif_rx_back_ring_t *rxb,
domid_t otherend_id)
{
const struct mbuf *mbuf = mbufc;/* current mbuf within the chain */
int gnt_idx = 0; /* index into grant table */
RING_IDX r_idx = pkt->car; /* index into rx ring buffer */
int r_ofs = 0; /* offset of next data within rx request's data area */
int m_ofs = 0; /* offset of next data within mbuf's data area */
/* size in bytes that still needs to be represented in the table */
uint16_t size_remaining;
size_remaining = (xnb_pkt_is_valid(pkt) != 0) ? pkt->size : 0;
while (size_remaining > 0) {
const netif_rx_request_t *rxq = RING_GET_REQUEST(rxb, r_idx);
const size_t mbuf_space = mbuf->m_len - m_ofs;
/* Xen shared pages have an implied size of PAGE_SIZE */
const size_t req_size = PAGE_SIZE;
const size_t pkt_space = req_size - r_ofs;
/*
* space is the largest amount of data that can be copied in the
* grant table's next entry
*/
const size_t space = MIN(pkt_space, mbuf_space);
/* TODO: handle this error condition without panicing */
KASSERT(gnt_idx < GNTTAB_LEN, ("Grant table is too short"));
gnttab[gnt_idx].dest.u.ref = rxq->gref;
gnttab[gnt_idx].dest.domid = otherend_id;
gnttab[gnt_idx].dest.offset = r_ofs;
gnttab[gnt_idx].source.u.gmfn = virt_to_mfn(
mtod(mbuf, vm_offset_t) + m_ofs);
gnttab[gnt_idx].source.offset = virt_to_offset(
mtod(mbuf, vm_offset_t) + m_ofs);
gnttab[gnt_idx].source.domid = DOMID_SELF;
gnttab[gnt_idx].len = space;
gnttab[gnt_idx].flags = GNTCOPY_dest_gref;
gnt_idx++;
r_ofs += space;
m_ofs += space;
size_remaining -= space;
if (req_size - r_ofs <= 0) {
/* Must move to the next rx request */
r_ofs = 0;
r_idx = (r_idx == pkt->car) ? pkt->cdr : r_idx + 1;
}
if (mbuf->m_len - m_ofs <= 0) {
/* Must move to the next mbuf */
m_ofs = 0;
mbuf = mbuf->m_next;
}
}
return gnt_idx;
}
/**
* Generates responses for all the requests that constituted pkt. Builds
* responses and writes them to the ring, but doesn't push the shared ring
* indices.
* \param[in] pkt the packet that needs a response
* \param[in] gnttab The grant copy table corresponding to this packet.
* Used to determine how many rsp->netif_rx_response_t's to
* generate.
* \param[in] n_entries Number of relevant entries in the grant table
* \param[out] ring Responses go here
* \return The number of RX requests that were consumed to generate
* the responses
*/
static int
xnb_rxpkt2rsp(const struct xnb_pkt *pkt, const gnttab_copy_table gnttab,
int n_entries, netif_rx_back_ring_t *ring)
{
/*
* This code makes the following assumptions:
* * All entries in gnttab set GNTCOPY_dest_gref
* * The entries in gnttab are grouped by their grefs: any two
* entries with the same gref must be adjacent
*/
int error = 0;
int gnt_idx, i;
int n_responses = 0;
grant_ref_t last_gref = GRANT_REF_INVALID;
RING_IDX r_idx;
KASSERT(gnttab != NULL, ("Received a null granttable copy"));
/*
* In the event of an error, we only need to send one response to the
* netfront. In that case, we musn't write any data to the responses
* after the one we send. So we must loop all the way through gnttab
* looking for errors before we generate any responses
*
* Since we're looping through the grant table anyway, we'll count the
* number of different gref's in it, which will tell us how many
* responses to generate
*/
for (gnt_idx = 0; gnt_idx < n_entries; gnt_idx++) {
int16_t status = gnttab[gnt_idx].status;
if (status != GNTST_okay) {
DPRINTF(
"Got error %d for hypervisor gnttab_copy status\n",
status);
error = 1;
break;
}
if (gnttab[gnt_idx].dest.u.ref != last_gref) {
n_responses++;
last_gref = gnttab[gnt_idx].dest.u.ref;
}
}
if (error != 0) {
uint16_t id;
netif_rx_response_t *rsp;
id = RING_GET_REQUEST(ring, ring->rsp_prod_pvt)->id;
rsp = RING_GET_RESPONSE(ring, ring->rsp_prod_pvt);
rsp->id = id;
rsp->status = NETIF_RSP_ERROR;
n_responses = 1;
} else {
gnt_idx = 0;
const int has_extra = pkt->flags & NETRXF_extra_info;
if (has_extra != 0)
n_responses++;
for (i = 0; i < n_responses; i++) {
netif_rx_request_t rxq;
netif_rx_response_t *rsp;
r_idx = ring->rsp_prod_pvt + i;
/*
* We copy the structure of rxq instead of making a
* pointer because it shares the same memory as rsp.
*/
rxq = *(RING_GET_REQUEST(ring, r_idx));
rsp = RING_GET_RESPONSE(ring, r_idx);
if (has_extra && (i == 1)) {
netif_extra_info_t *ext =
(netif_extra_info_t*)rsp;
ext->type = XEN_NETIF_EXTRA_TYPE_GSO;
ext->flags = 0;
ext->u.gso.size = pkt->extra.u.gso.size;
ext->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
ext->u.gso.pad = 0;
ext->u.gso.features = 0;
} else {
rsp->id = rxq.id;
rsp->status = GNTST_okay;
rsp->offset = 0;
rsp->flags = 0;
if (i < pkt->list_len - 1)
rsp->flags |= NETRXF_more_data;
if ((i == 0) && has_extra)
rsp->flags |= NETRXF_extra_info;
if ((i == 0) &&
(pkt->flags & NETRXF_data_validated)) {
rsp->flags |= NETRXF_data_validated;
rsp->flags |= NETRXF_csum_blank;
}
rsp->status = 0;
for (; gnttab[gnt_idx].dest.u.ref == rxq.gref;
gnt_idx++) {
rsp->status += gnttab[gnt_idx].len;
}
}
}
}
ring->req_cons += n_responses;
ring->rsp_prod_pvt += n_responses;
return n_responses;
}
#if defined(INET) || defined(INET6)
/**
* Add IP, TCP, and/or UDP checksums to every mbuf in a chain. The first mbuf
* in the chain must start with a struct ether_header.
*
* XXX This function will perform incorrectly on UDP packets that are split up
* into multiple ethernet frames.
*/
static void
xnb_add_mbuf_cksum(struct mbuf *mbufc)
{
struct ether_header *eh;
struct ip *iph;
uint16_t ether_type;
eh = mtod(mbufc, struct ether_header*);
ether_type = ntohs(eh->ether_type);
if (ether_type != ETHERTYPE_IP) {
/* Nothing to calculate */
return;
}
iph = (struct ip*)(eh + 1);
if (mbufc->m_pkthdr.csum_flags & CSUM_IP_VALID) {
iph->ip_sum = 0;
iph->ip_sum = in_cksum_hdr(iph);
}
switch (iph->ip_p) {
case IPPROTO_TCP:
if (mbufc->m_pkthdr.csum_flags & CSUM_IP_VALID) {
size_t tcplen = ntohs(iph->ip_len) - sizeof(struct ip);
struct tcphdr *th = (struct tcphdr*)(iph + 1);
th->th_sum = in_pseudo(iph->ip_src.s_addr,
iph->ip_dst.s_addr, htons(IPPROTO_TCP + tcplen));
th->th_sum = in_cksum_skip(mbufc,
sizeof(struct ether_header) + ntohs(iph->ip_len),
sizeof(struct ether_header) + (iph->ip_hl << 2));
}
break;
case IPPROTO_UDP:
if (mbufc->m_pkthdr.csum_flags & CSUM_IP_VALID) {
size_t udplen = ntohs(iph->ip_len) - sizeof(struct ip);
struct udphdr *uh = (struct udphdr*)(iph + 1);
uh->uh_sum = in_pseudo(iph->ip_src.s_addr,
iph->ip_dst.s_addr, htons(IPPROTO_UDP + udplen));
uh->uh_sum = in_cksum_skip(mbufc,
sizeof(struct ether_header) + ntohs(iph->ip_len),
sizeof(struct ether_header) + (iph->ip_hl << 2));
}
break;
default:
break;
}
}
#endif /* INET || INET6 */
static void
xnb_stop(struct xnb_softc *xnb)
{
struct ifnet *ifp;
mtx_assert(&xnb->sc_lock, MA_OWNED);
ifp = xnb->xnb_ifp;
ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
if_link_state_change(ifp, LINK_STATE_DOWN);
}
static int
xnb_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct xnb_softc *xnb = ifp->if_softc;
struct ifreq *ifr = (struct ifreq*) data;
#ifdef INET
struct ifaddr *ifa = (struct ifaddr*)data;
#endif
int error = 0;
switch (cmd) {
case SIOCSIFFLAGS:
mtx_lock(&xnb->sc_lock);
if (ifp->if_flags & IFF_UP) {
xnb_ifinit_locked(xnb);
} else {
if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
xnb_stop(xnb);
}
}
/*
* Note: netfront sets a variable named xn_if_flags
* here, but that variable is never read
*/
mtx_unlock(&xnb->sc_lock);
break;
case SIOCSIFADDR:
#ifdef INET
mtx_lock(&xnb->sc_lock);
if (ifa->ifa_addr->sa_family == AF_INET) {
ifp->if_flags |= IFF_UP;
if (!(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
ifp->if_drv_flags &= ~(IFF_DRV_RUNNING |
IFF_DRV_OACTIVE);
if_link_state_change(ifp,
LINK_STATE_DOWN);
ifp->if_drv_flags |= IFF_DRV_RUNNING;
ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
if_link_state_change(ifp,
LINK_STATE_UP);
}
arp_ifinit(ifp, ifa);
mtx_unlock(&xnb->sc_lock);
} else {
mtx_unlock(&xnb->sc_lock);
#endif
error = ether_ioctl(ifp, cmd, data);
#ifdef INET
}
#endif
break;
case SIOCSIFCAP:
mtx_lock(&xnb->sc_lock);
if (ifr->ifr_reqcap & IFCAP_TXCSUM) {
ifp->if_capenable |= IFCAP_TXCSUM;
ifp->if_hwassist |= XNB_CSUM_FEATURES;
} else {
ifp->if_capenable &= ~(IFCAP_TXCSUM);
ifp->if_hwassist &= ~(XNB_CSUM_FEATURES);
}
if ((ifr->ifr_reqcap & IFCAP_RXCSUM)) {
ifp->if_capenable |= IFCAP_RXCSUM;
} else {
ifp->if_capenable &= ~(IFCAP_RXCSUM);
}
/*
* TODO enable TSO4 and LRO once we no longer need
* to calculate checksums in software
*/
#if 0
if (ifr->if_reqcap |= IFCAP_TSO4) {
if (IFCAP_TXCSUM & ifp->if_capenable) {
printf("xnb: Xen netif requires that "
"TXCSUM be enabled in order "
"to use TSO4\n");
error = EINVAL;
} else {
ifp->if_capenable |= IFCAP_TSO4;
ifp->if_hwassist |= CSUM_TSO;
}
} else {
ifp->if_capenable &= ~(IFCAP_TSO4);
ifp->if_hwassist &= ~(CSUM_TSO);
}
if (ifr->ifreqcap |= IFCAP_LRO) {
ifp->if_capenable |= IFCAP_LRO;
} else {
ifp->if_capenable &= ~(IFCAP_LRO);
}
#endif
mtx_unlock(&xnb->sc_lock);
break;
case SIOCSIFMTU:
ifp->if_mtu = ifr->ifr_mtu;
ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
xnb_ifinit(xnb);
break;
case SIOCADDMULTI:
case SIOCDELMULTI:
break;
case SIOCSIFMEDIA:
case SIOCGIFMEDIA:
error = ifmedia_ioctl(ifp, ifr, &xnb->sc_media, cmd);
break;
default:
error = ether_ioctl(ifp, cmd, data);
break;
}
return (error);
}
static void
xnb_start_locked(struct ifnet *ifp)
{
netif_rx_back_ring_t *rxb;
struct xnb_softc *xnb;
struct mbuf *mbufc;
RING_IDX req_prod_local;
xnb = ifp->if_softc;
rxb = &xnb->ring_configs[XNB_RING_TYPE_RX].back_ring.rx_ring;
if (!xnb->carrier)
return;
do {
int out_of_space = 0;
int notify;
req_prod_local = rxb->sring->req_prod;
xen_rmb();
for (;;) {
int error;
IF_DEQUEUE(&ifp->if_snd, mbufc);
if (mbufc == NULL)
break;
error = xnb_send(rxb, xnb->otherend_id, mbufc,
xnb->rx_gnttab);
switch (error) {
case EAGAIN:
/*
* Insufficient space in the ring.
* Requeue pkt and send when space is
* available.
*/
IF_PREPEND(&ifp->if_snd, mbufc);
/*
* Perhaps the frontend missed an IRQ
* and went to sleep. Notify it to wake
* it up.
*/
out_of_space = 1;
break;
case EINVAL:
/* OS gave a corrupt packet. Drop it.*/
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
/* FALLTHROUGH */
default:
/* Send succeeded, or packet had error.
* Free the packet */
if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
if (mbufc)
m_freem(mbufc);
break;
}
if (out_of_space != 0)
break;
}
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(rxb, notify);
if ((notify != 0) || (out_of_space != 0))
xen_intr_signal(xnb->xen_intr_handle);
rxb->sring->req_event = req_prod_local + 1;
xen_mb();
} while (rxb->sring->req_prod != req_prod_local) ;
}
/**
* Sends one packet to the ring. Blocks until the packet is on the ring
* \param[in] mbufc Contains one packet to send. Caller must free
* \param[in,out] rxb The packet will be pushed onto this ring, but the
* otherend will not be notified.
* \param[in] otherend The domain ID of the other end of the connection
* \retval EAGAIN The ring did not have enough space for the packet.
* The ring has not been modified
* \param[in,out] gnttab Pointer to enough memory for a grant table. We make
* this a function parameter so that we will take less
* stack space.
* \retval EINVAL mbufc was corrupt or not convertible into a pkt
*/
static int
xnb_send(netif_rx_back_ring_t *ring, domid_t otherend, const struct mbuf *mbufc,
gnttab_copy_table gnttab)
{
struct xnb_pkt pkt;
int error, n_entries;
RING_IDX space;
space = ring->sring->req_prod - ring->req_cons;
error = xnb_mbufc2pkt(mbufc, &pkt, ring->rsp_prod_pvt, space);
if (error != 0)
return error;
n_entries = xnb_rxpkt2gnttab(&pkt, mbufc, gnttab, ring, otherend);
if (n_entries != 0) {
int __unused hv_ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
gnttab, n_entries);
KASSERT(hv_ret == 0, ("HYPERVISOR_grant_table_op returned %d\n",
hv_ret));
}
xnb_rxpkt2rsp(&pkt, gnttab, n_entries, ring);
return 0;
}
static void
xnb_start(struct ifnet *ifp)
{
struct xnb_softc *xnb;
xnb = ifp->if_softc;
mtx_lock(&xnb->rx_lock);
xnb_start_locked(ifp);
mtx_unlock(&xnb->rx_lock);
}
/* equivalent of network_open() in Linux */
static void
xnb_ifinit_locked(struct xnb_softc *xnb)
{
struct ifnet *ifp;
ifp = xnb->xnb_ifp;
mtx_assert(&xnb->sc_lock, MA_OWNED);
if (ifp->if_drv_flags & IFF_DRV_RUNNING)
return;
xnb_stop(xnb);
ifp->if_drv_flags |= IFF_DRV_RUNNING;
ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
if_link_state_change(ifp, LINK_STATE_UP);
}
static void
xnb_ifinit(void *xsc)
{
struct xnb_softc *xnb = xsc;
mtx_lock(&xnb->sc_lock);
xnb_ifinit_locked(xnb);
mtx_unlock(&xnb->sc_lock);
}
/**
* Callback used by the generic networking code to tell us when our carrier
* state has changed. Since we don't have a physical carrier, we don't care
*/
static int
xnb_ifmedia_upd(struct ifnet *ifp)
{
return (0);
}
/**
* Callback used by the generic networking code to ask us what our carrier
* state is. Since we don't have a physical carrier, this is very simple
*/
static void
xnb_ifmedia_sts(struct ifnet *ifp, struct ifmediareq *ifmr)
{
ifmr->ifm_status = IFM_AVALID|IFM_ACTIVE;
ifmr->ifm_active = IFM_ETHER|IFM_MANUAL;
}
/*---------------------------- NewBus Registration ---------------------------*/
static device_method_t xnb_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, xnb_probe),
DEVMETHOD(device_attach, xnb_attach),
DEVMETHOD(device_detach, xnb_detach),
DEVMETHOD(device_shutdown, bus_generic_shutdown),
DEVMETHOD(device_suspend, xnb_suspend),
DEVMETHOD(device_resume, xnb_resume),
/* Xenbus interface */
DEVMETHOD(xenbus_otherend_changed, xnb_frontend_changed),
{ 0, 0 }
};
static driver_t xnb_driver = {
"xnb",
xnb_methods,
sizeof(struct xnb_softc),
};
DRIVER_MODULE(xnb, xenbusb_back, xnb_driver, 0, 0);
/*-------------------------- Unit Tests -------------------------------------*/
#ifdef XNB_DEBUG
#include "netback_unit_tests.c"
#endif
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