numam-dpdk/drivers/net/vdev_netvsc/vdev_netvsc.c
Matan Azrad e7dc5d7bec net/vdev_netvsc: implement core functionality
As described in more details in the attached documentation (see patch
contents), this virtual device driver manages NetVSC interfaces in virtual
machines hosted by Hyper-V/Azure platforms.

This driver does not manage traffic nor Ethernet devices directly; it acts
as a thin configuration layer that automatically instantiates and controls
fail-safe PMD instances combining tap and PCI sub-devices, so that each
NetVSC interface is exposed as a single consolidated port to DPDK
applications.

PCI sub-devices being hot-pluggable (e.g. during VM migration),
applications automatically benefit from increased throughput when present
and automatic fallback on NetVSC otherwise without interruption thanks to
fail-safe's hot-plug handling.

Once initialized, the sole job of the vdev_netvsc driver is to regularly
scan for PCI devices to associate with NetVSC interfaces and feed their
addresses to corresponding fail-safe instances.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Matan Azrad <matan@mellanox.com>
2018-01-21 15:51:52 +01:00

648 lines
17 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause
* Copyright 2017 6WIND S.A.
* Copyright 2017 Mellanox Technologies, Ltd.
*/
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <linux/sockios.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/ip.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <unistd.h>
#include <rte_alarm.h>
#include <rte_bus.h>
#include <rte_bus_vdev.h>
#include <rte_common.h>
#include <rte_config.h>
#include <rte_dev.h>
#include <rte_errno.h>
#include <rte_ethdev.h>
#include <rte_ether.h>
#include <rte_kvargs.h>
#include <rte_log.h>
#define VDEV_NETVSC_DRIVER net_vdev_netvsc
#define VDEV_NETVSC_ARG_IFACE "iface"
#define VDEV_NETVSC_ARG_MAC "mac"
#define VDEV_NETVSC_PROBE_MS 1000
#define NETVSC_CLASS_ID "{f8615163-df3e-46c5-913f-f2d2f965ed0e}"
#define DRV_LOG(level, ...) \
rte_log(RTE_LOG_ ## level, \
vdev_netvsc_logtype, \
RTE_FMT(RTE_STR(VDEV_NETVSC_DRIVER) ": " \
RTE_FMT_HEAD(__VA_ARGS__,) "\n", \
RTE_FMT_TAIL(__VA_ARGS__,)))
/** Driver-specific log messages type. */
static int vdev_netvsc_logtype;
/** Context structure for a vdev_netvsc instance. */
struct vdev_netvsc_ctx {
LIST_ENTRY(vdev_netvsc_ctx) entry; /**< Next entry in list. */
unsigned int id; /**< Unique ID. */
char name[64]; /**< Unique name. */
char devname[64]; /**< Fail-safe instance name. */
char devargs[256]; /**< Fail-safe device arguments. */
char if_name[IF_NAMESIZE]; /**< NetVSC netdevice name. */
unsigned int if_index; /**< NetVSC netdevice index. */
struct ether_addr if_addr; /**< NetVSC MAC address. */
int pipe[2]; /**< Fail-safe communication pipe. */
char yield[256]; /**< PCI sub-device arguments. */
};
/** Context list is common to all driver instances. */
static LIST_HEAD(, vdev_netvsc_ctx) vdev_netvsc_ctx_list =
LIST_HEAD_INITIALIZER(vdev_netvsc_ctx_list);
/** Number of entries in context list. */
static unsigned int vdev_netvsc_ctx_count;
/** Number of driver instances relying on context list. */
static unsigned int vdev_netvsc_ctx_inst;
/**
* Destroy a vdev_netvsc context instance.
*
* @param ctx
* Context to destroy.
*/
static void
vdev_netvsc_ctx_destroy(struct vdev_netvsc_ctx *ctx)
{
if (ctx->pipe[0] != -1)
close(ctx->pipe[0]);
if (ctx->pipe[1] != -1)
close(ctx->pipe[1]);
free(ctx);
}
/**
* Iterate over system network interfaces.
*
* This function runs a given callback function for each netdevice found on
* the system.
*
* @param func
* Callback function pointer. List traversal is aborted when this function
* returns a nonzero value.
* @param ...
* Variable parameter list passed as @p va_list to @p func.
*
* @return
* 0 when the entire list is traversed successfully, a negative error code
* in case or failure, or the nonzero value returned by @p func when list
* traversal is aborted.
*/
static int
vdev_netvsc_foreach_iface(int (*func)(const struct if_nameindex *iface,
const struct ether_addr *eth_addr,
va_list ap), ...)
{
struct if_nameindex *iface = if_nameindex();
int s = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
unsigned int i;
int ret = 0;
if (!iface) {
ret = -ENOBUFS;
DRV_LOG(ERR, "cannot retrieve system network interfaces");
goto error;
}
if (s == -1) {
ret = -errno;
DRV_LOG(ERR, "cannot open socket: %s", rte_strerror(errno));
goto error;
}
for (i = 0; iface[i].if_name; ++i) {
struct ifreq req;
struct ether_addr eth_addr;
va_list ap;
strncpy(req.ifr_name, iface[i].if_name, sizeof(req.ifr_name));
if (ioctl(s, SIOCGIFHWADDR, &req) == -1) {
DRV_LOG(WARNING, "cannot retrieve information about"
" interface \"%s\": %s",
req.ifr_name, rte_strerror(errno));
continue;
}
if (req.ifr_hwaddr.sa_family != ARPHRD_ETHER) {
DRV_LOG(DEBUG, "interface %s is non-ethernet device",
req.ifr_name);
continue;
}
memcpy(eth_addr.addr_bytes, req.ifr_hwaddr.sa_data,
RTE_DIM(eth_addr.addr_bytes));
va_start(ap, func);
ret = func(&iface[i], &eth_addr, ap);
va_end(ap);
if (ret)
break;
}
error:
if (s != -1)
close(s);
if (iface)
if_freenameindex(iface);
return ret;
}
/**
* Determine if a network interface is NetVSC.
*
* @param[in] iface
* Pointer to netdevice description structure (name and index).
*
* @return
* A nonzero value when interface is detected as NetVSC. In case of error,
* rte_errno is updated and 0 returned.
*/
static int
vdev_netvsc_iface_is_netvsc(const struct if_nameindex *iface)
{
static const char temp[] = "/sys/class/net/%s/device/class_id";
char path[sizeof(temp) + IF_NAMESIZE];
FILE *f;
int ret;
int len = 0;
ret = snprintf(path, sizeof(path), temp, iface->if_name);
if (ret == -1 || (size_t)ret >= sizeof(path)) {
rte_errno = ENOBUFS;
return 0;
}
f = fopen(path, "r");
if (!f) {
rte_errno = errno;
return 0;
}
ret = fscanf(f, NETVSC_CLASS_ID "%n", &len);
if (ret == EOF)
rte_errno = errno;
ret = len == (int)strlen(NETVSC_CLASS_ID);
fclose(f);
return ret;
}
/**
* Retrieve network interface data from sysfs symbolic link.
*
* @param[out] buf
* Output data buffer.
* @param size
* Output buffer size.
* @param[in] if_name
* Netdevice name.
* @param[in] relpath
* Symbolic link path relative to netdevice sysfs entry.
*
* @return
* 0 on success, a negative error code otherwise.
*/
static int
vdev_netvsc_sysfs_readlink(char *buf, size_t size, const char *if_name,
const char *relpath)
{
int ret;
ret = snprintf(buf, size, "/sys/class/net/%s/%s", if_name, relpath);
if (ret == -1 || (size_t)ret >= size)
return -ENOBUFS;
ret = readlink(buf, buf, size);
if (ret == -1)
return -errno;
if ((size_t)ret >= size - 1)
return -ENOBUFS;
buf[ret] = '\0';
return 0;
}
/**
* Probe a network interface to associate with vdev_netvsc context.
*
* This function determines if the network device matches the properties of
* the NetVSC interface associated with the vdev_netvsc context and
* communicates its bus address to the fail-safe PMD instance if so.
*
* It is normally used with vdev_netvsc_foreach_iface().
*
* @param[in] iface
* Pointer to netdevice description structure (name and index).
* @param[in] eth_addr
* MAC address associated with @p iface.
* @param ap
* Variable arguments list comprising:
*
* - struct vdev_netvsc_ctx *ctx:
* Context to associate network interface with.
*
* @return
* A nonzero value when interface matches, 0 otherwise or in case of
* error.
*/
static int
vdev_netvsc_device_probe(const struct if_nameindex *iface,
const struct ether_addr *eth_addr,
va_list ap)
{
struct vdev_netvsc_ctx *ctx = va_arg(ap, struct vdev_netvsc_ctx *);
char buf[RTE_MAX(sizeof(ctx->yield), 256u)];
const char *addr;
size_t len;
int ret;
/* Skip non-matching or unwanted NetVSC interfaces. */
if (ctx->if_index == iface->if_index) {
if (!strcmp(ctx->if_name, iface->if_name))
return 0;
DRV_LOG(DEBUG,
"NetVSC interface \"%s\" (index %u) renamed \"%s\"",
ctx->if_name, ctx->if_index, iface->if_name);
strncpy(ctx->if_name, iface->if_name, sizeof(ctx->if_name));
return 0;
}
if (vdev_netvsc_iface_is_netvsc(iface))
return 0;
if (!is_same_ether_addr(eth_addr, &ctx->if_addr))
return 0;
/* Look for associated PCI device. */
ret = vdev_netvsc_sysfs_readlink(buf, sizeof(buf), iface->if_name,
"device/subsystem");
if (ret)
return 0;
addr = strrchr(buf, '/');
addr = addr ? addr + 1 : buf;
if (strcmp(addr, "pci"))
return 0;
ret = vdev_netvsc_sysfs_readlink(buf, sizeof(buf), iface->if_name,
"device");
if (ret)
return 0;
addr = strrchr(buf, '/');
addr = addr ? addr + 1 : buf;
len = strlen(addr);
if (!len)
return 0;
/* Send PCI device argument to fail-safe PMD instance. */
if (strcmp(addr, ctx->yield))
DRV_LOG(DEBUG, "associating PCI device \"%s\" with NetVSC"
" interface \"%s\" (index %u)", addr, ctx->if_name,
ctx->if_index);
memmove(buf, addr, len + 1);
addr = buf;
buf[len] = '\n';
ret = write(ctx->pipe[1], addr, len + 1);
buf[len] = '\0';
if (ret == -1) {
if (errno == EINTR || errno == EAGAIN)
return 1;
DRV_LOG(WARNING, "cannot associate PCI device name \"%s\" with"
" interface \"%s\": %s", addr, ctx->if_name,
rte_strerror(errno));
return 1;
}
if ((size_t)ret != len + 1) {
/*
* Attempt to override previous partial write, no need to
* recover if that fails.
*/
ret = write(ctx->pipe[1], "\n", 1);
(void)ret;
return 1;
}
fsync(ctx->pipe[1]);
memcpy(ctx->yield, addr, len + 1);
return 1;
}
/**
* Alarm callback that regularly probes system network interfaces.
*
* This callback runs at a frequency determined by VDEV_NETVSC_PROBE_MS as
* long as an vdev_netvsc context instance exists.
*
* @param arg
* Ignored.
*/
static void
vdev_netvsc_alarm(__rte_unused void *arg)
{
struct vdev_netvsc_ctx *ctx;
int ret;
LIST_FOREACH(ctx, &vdev_netvsc_ctx_list, entry) {
ret = vdev_netvsc_foreach_iface(vdev_netvsc_device_probe, ctx);
if (ret)
break;
}
if (!vdev_netvsc_ctx_count)
return;
ret = rte_eal_alarm_set(VDEV_NETVSC_PROBE_MS * 1000,
vdev_netvsc_alarm, NULL);
if (ret < 0) {
DRV_LOG(ERR, "unable to reschedule alarm callback: %s",
rte_strerror(-ret));
}
}
/**
* Probe a NetVSC interface to generate a vdev_netvsc context from.
*
* This function instantiates vdev_netvsc contexts either for all NetVSC
* devices found on the system or only a subset provided as device
* arguments.
*
* It is normally used with vdev_netvsc_foreach_iface().
*
* @param[in] iface
* Pointer to netdevice description structure (name and index).
* @param[in] eth_addr
* MAC address associated with @p iface.
* @param ap
* Variable arguments list comprising:
*
* - const char *name:
* Name associated with current driver instance.
*
* - struct rte_kvargs *kvargs:
* Device arguments provided to current driver instance.
*
* - unsigned int specified:
* Number of specific netdevices provided as device arguments.
*
* - unsigned int *matched:
* The number of specified netdevices matched by this function.
*
* @return
* A nonzero value when interface matches, 0 otherwise or in case of
* error.
*/
static int
vdev_netvsc_netvsc_probe(const struct if_nameindex *iface,
const struct ether_addr *eth_addr,
va_list ap)
{
const char *name = va_arg(ap, const char *);
struct rte_kvargs *kvargs = va_arg(ap, struct rte_kvargs *);
unsigned int specified = va_arg(ap, unsigned int);
unsigned int *matched = va_arg(ap, unsigned int *);
unsigned int i;
struct vdev_netvsc_ctx *ctx;
int ret;
/* Probe all interfaces when none are specified. */
if (specified) {
for (i = 0; i != kvargs->count; ++i) {
const struct rte_kvargs_pair *pair = &kvargs->pairs[i];
if (!strcmp(pair->key, VDEV_NETVSC_ARG_IFACE)) {
if (!strcmp(pair->value, iface->if_name))
break;
} else if (!strcmp(pair->key, VDEV_NETVSC_ARG_MAC)) {
struct ether_addr tmp;
if (sscanf(pair->value,
"%" SCNx8 ":%" SCNx8 ":%" SCNx8 ":"
"%" SCNx8 ":%" SCNx8 ":%" SCNx8,
&tmp.addr_bytes[0],
&tmp.addr_bytes[1],
&tmp.addr_bytes[2],
&tmp.addr_bytes[3],
&tmp.addr_bytes[4],
&tmp.addr_bytes[5]) != 6) {
DRV_LOG(ERR,
"invalid MAC address format"
" \"%s\"",
pair->value);
return -EINVAL;
}
if (is_same_ether_addr(eth_addr, &tmp))
break;
}
}
if (i == kvargs->count)
return 0;
++(*matched);
}
/* Weed out interfaces already handled. */
LIST_FOREACH(ctx, &vdev_netvsc_ctx_list, entry)
if (ctx->if_index == iface->if_index)
break;
if (ctx) {
if (!specified)
return 0;
DRV_LOG(WARNING,
"interface \"%s\" (index %u) is already handled,"
" skipping",
iface->if_name, iface->if_index);
return 0;
}
if (!vdev_netvsc_iface_is_netvsc(iface)) {
if (!specified)
return 0;
DRV_LOG(WARNING,
"interface \"%s\" (index %u) is not NetVSC,"
" skipping",
iface->if_name, iface->if_index);
return 0;
}
/* Create interface context. */
ctx = calloc(1, sizeof(*ctx));
if (!ctx) {
ret = -errno;
DRV_LOG(ERR, "cannot allocate context for interface \"%s\": %s",
iface->if_name, rte_strerror(errno));
goto error;
}
ctx->id = vdev_netvsc_ctx_count;
strncpy(ctx->if_name, iface->if_name, sizeof(ctx->if_name));
ctx->if_index = iface->if_index;
ctx->if_addr = *eth_addr;
ctx->pipe[0] = -1;
ctx->pipe[1] = -1;
ctx->yield[0] = '\0';
if (pipe(ctx->pipe) == -1) {
ret = -errno;
DRV_LOG(ERR,
"cannot allocate control pipe for interface \"%s\": %s",
ctx->if_name, rte_strerror(errno));
goto error;
}
for (i = 0; i != RTE_DIM(ctx->pipe); ++i) {
int flf = fcntl(ctx->pipe[i], F_GETFL);
if (flf != -1 &&
fcntl(ctx->pipe[i], F_SETFL, flf | O_NONBLOCK) != -1)
continue;
ret = -errno;
DRV_LOG(ERR, "cannot toggle non-blocking flag on control file"
" descriptor #%u (%d): %s", i, ctx->pipe[i],
rte_strerror(errno));
goto error;
}
/* Generate virtual device name and arguments. */
i = 0;
ret = snprintf(ctx->name, sizeof(ctx->name), "%s_id%u",
name, ctx->id);
if (ret == -1 || (size_t)ret >= sizeof(ctx->name))
++i;
ret = snprintf(ctx->devname, sizeof(ctx->devname), "net_failsafe_%s",
ctx->name);
if (ret == -1 || (size_t)ret >= sizeof(ctx->devname))
++i;
ret = snprintf(ctx->devargs, sizeof(ctx->devargs),
"fd(%d),dev(net_tap_%s,remote=%s)",
ctx->pipe[0], ctx->name, ctx->if_name);
if (ret == -1 || (size_t)ret >= sizeof(ctx->devargs))
++i;
if (i) {
ret = -ENOBUFS;
DRV_LOG(ERR, "generated virtual device name or argument list"
" too long for interface \"%s\"", ctx->if_name);
goto error;
}
/* Request virtual device generation. */
DRV_LOG(DEBUG, "generating virtual device \"%s\" with arguments \"%s\"",
ctx->devname, ctx->devargs);
vdev_netvsc_foreach_iface(vdev_netvsc_device_probe, ctx);
ret = rte_eal_hotplug_add("vdev", ctx->devname, ctx->devargs);
if (ret)
goto error;
LIST_INSERT_HEAD(&vdev_netvsc_ctx_list, ctx, entry);
++vdev_netvsc_ctx_count;
DRV_LOG(DEBUG, "added NetVSC interface \"%s\" to context list",
ctx->if_name);
return 0;
error:
if (ctx)
vdev_netvsc_ctx_destroy(ctx);
return ret;
}
/**
* Probe NetVSC interfaces.
*
* This function probes system netdevices according to the specified device
* arguments and starts a periodic alarm callback to notify the resulting
* fail-safe PMD instances of their sub-devices whereabouts.
*
* @param dev
* Virtual device context for driver instance.
*
* @return
* Always 0, even in case of errors.
*/
static int
vdev_netvsc_vdev_probe(struct rte_vdev_device *dev)
{
static const char *const vdev_netvsc_arg[] = {
VDEV_NETVSC_ARG_IFACE,
VDEV_NETVSC_ARG_MAC,
NULL,
};
const char *name = rte_vdev_device_name(dev);
const char *args = rte_vdev_device_args(dev);
struct rte_kvargs *kvargs = rte_kvargs_parse(args ? args : "",
vdev_netvsc_arg);
unsigned int specified = 0;
unsigned int matched = 0;
unsigned int i;
int ret;
DRV_LOG(DEBUG, "invoked as \"%s\", using arguments \"%s\"", name, args);
if (!kvargs) {
DRV_LOG(ERR, "cannot parse arguments list");
goto error;
}
for (i = 0; i != kvargs->count; ++i) {
const struct rte_kvargs_pair *pair = &kvargs->pairs[i];
if (!strcmp(pair->key, VDEV_NETVSC_ARG_IFACE) ||
!strcmp(pair->key, VDEV_NETVSC_ARG_MAC))
++specified;
}
rte_eal_alarm_cancel(vdev_netvsc_alarm, NULL);
/* Gather interfaces. */
ret = vdev_netvsc_foreach_iface(vdev_netvsc_netvsc_probe, name, kvargs,
specified, &matched);
if (ret < 0)
goto error;
if (matched < specified)
DRV_LOG(WARNING,
"some of the specified parameters did not match"
" recognized network interfaces");
ret = rte_eal_alarm_set(VDEV_NETVSC_PROBE_MS * 1000,
vdev_netvsc_alarm, NULL);
if (ret < 0) {
DRV_LOG(ERR, "unable to schedule alarm callback: %s",
rte_strerror(-ret));
goto error;
}
error:
if (kvargs)
rte_kvargs_free(kvargs);
++vdev_netvsc_ctx_inst;
return 0;
}
/**
* Remove driver instance.
*
* The alarm callback and underlying vdev_netvsc context instances are only
* destroyed after the last PMD instance is removed.
*
* @param dev
* Virtual device context for driver instance.
*
* @return
* Always 0.
*/
static int
vdev_netvsc_vdev_remove(__rte_unused struct rte_vdev_device *dev)
{
if (--vdev_netvsc_ctx_inst)
return 0;
rte_eal_alarm_cancel(vdev_netvsc_alarm, NULL);
while (!LIST_EMPTY(&vdev_netvsc_ctx_list)) {
struct vdev_netvsc_ctx *ctx = LIST_FIRST(&vdev_netvsc_ctx_list);
LIST_REMOVE(ctx, entry);
--vdev_netvsc_ctx_count;
vdev_netvsc_ctx_destroy(ctx);
}
return 0;
}
/** Virtual device descriptor. */
static struct rte_vdev_driver vdev_netvsc_vdev = {
.probe = vdev_netvsc_vdev_probe,
.remove = vdev_netvsc_vdev_remove,
};
RTE_PMD_REGISTER_VDEV(VDEV_NETVSC_DRIVER, vdev_netvsc_vdev);
RTE_PMD_REGISTER_ALIAS(VDEV_NETVSC_DRIVER, eth_vdev_netvsc);
RTE_PMD_REGISTER_PARAM_STRING(net_vdev_netvsc,
VDEV_NETVSC_ARG_IFACE "=<string> "
VDEV_NETVSC_ARG_MAC "=<string>");
/** Initialize driver log type. */
RTE_INIT(vdev_netvsc_init_log)
{
vdev_netvsc_logtype = rte_log_register("pmd.vdev_netvsc");
if (vdev_netvsc_logtype >= 0)
rte_log_set_level(vdev_netvsc_logtype, RTE_LOG_NOTICE);
}