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netdevsim: fib: Add debugfs to debug route offload failure
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Add "fail_route_offload" flag to disallow offloading routes.
It is needed to test "offload failed" notifications.

Create the flag as part of nsim_fib_create() under fib directory and set
it to false by default.

When FIB_EVENT_ENTRY_{REPLACE, APPEND} are triggered and
"fail_route_offload" value is true, set the appropriate hardware flag to
make the kernel emit RTM_NEWROUTE notification with RTM_F_OFFLOAD_FAILED
flag.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Amit Cohen authored and David S. Miller committed Feb 9, 2021
1 parent f57ab5b commit 134c753
Showing 1 changed file with 112 additions and 2 deletions.
114 changes: 112 additions & 2 deletions drivers/net/netdevsim/fib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
#include <net/fib_rules.h>
#include <net/net_namespace.h>
#include <net/nexthop.h>
#include <linux/debugfs.h>

#include "netdevsim.h"

Expand Down Expand Up @@ -53,6 +54,8 @@ struct nsim_fib_data {
struct work_struct fib_event_work;
struct list_head fib_event_queue;
spinlock_t fib_event_queue_lock; /* Protects fib event queue list */
struct dentry *ddir;
bool fail_route_offload;
};

struct nsim_fib_rt_key {
Expand Down Expand Up @@ -303,6 +306,25 @@ nsim_fib4_rt_lookup(struct rhashtable *fib_rt_ht,
return container_of(fib_rt, struct nsim_fib4_rt, common);
}

static void
nsim_fib4_rt_offload_failed_flag_set(struct net *net,
struct fib_entry_notifier_info *fen_info)
{
u32 *p_dst = (u32 *)&fen_info->dst;
struct fib_rt_info fri;

fri.fi = fen_info->fi;
fri.tb_id = fen_info->tb_id;
fri.dst = cpu_to_be32(*p_dst);
fri.dst_len = fen_info->dst_len;
fri.tos = fen_info->tos;
fri.type = fen_info->type;
fri.offload = false;
fri.trap = false;
fri.offload_failed = true;
fib_alias_hw_flags_set(net, &fri);
}

static void nsim_fib4_rt_hw_flags_set(struct net *net,
const struct nsim_fib4_rt *fib4_rt,
bool trap)
Expand Down Expand Up @@ -384,6 +406,15 @@ static int nsim_fib4_rt_insert(struct nsim_fib_data *data,
struct nsim_fib4_rt *fib4_rt, *fib4_rt_old;
int err;

if (data->fail_route_offload) {
/* For testing purposes, user set debugfs fail_route_offload
* value to true. Simulate hardware programming latency and then
* fail.
*/
msleep(1);
return -EINVAL;
}

fib4_rt = nsim_fib4_rt_create(data, fen_info);
if (!fib4_rt)
return -ENOMEM;
Expand Down Expand Up @@ -423,6 +454,11 @@ static int nsim_fib4_event(struct nsim_fib_data *data,
switch (event) {
case FIB_EVENT_ENTRY_REPLACE:
err = nsim_fib4_rt_insert(data, fen_info);
if (err) {
struct net *net = devlink_net(data->devlink);

nsim_fib4_rt_offload_failed_flag_set(net, fen_info);
}
break;
case FIB_EVENT_ENTRY_DEL:
nsim_fib4_rt_remove(data, fen_info);
Expand Down Expand Up @@ -564,6 +600,15 @@ static int nsim_fib6_rt_append(struct nsim_fib_data *data,
struct nsim_fib6_rt *fib6_rt;
int i, err;

if (data->fail_route_offload) {
/* For testing purposes, user set debugfs fail_route_offload
* value to true. Simulate hardware programming latency and then
* fail.
*/
msleep(1);
return -EINVAL;
}

fib6_rt = nsim_fib6_rt_lookup(&data->fib_rt_ht, rt);
if (!fib6_rt)
return -EINVAL;
Expand All @@ -586,6 +631,26 @@ static int nsim_fib6_rt_append(struct nsim_fib_data *data,
return err;
}

#if IS_ENABLED(CONFIG_IPV6)
static void nsim_fib6_rt_offload_failed_flag_set(struct nsim_fib_data *data,
struct fib6_info **rt_arr,
unsigned int nrt6)

{
struct net *net = devlink_net(data->devlink);
int i;

for (i = 0; i < nrt6; i++)
fib6_info_hw_flags_set(net, rt_arr[i], false, false, true);
}
#else
static void nsim_fib6_rt_offload_failed_flag_set(struct nsim_fib_data *data,
struct fib6_info **rt_arr,
unsigned int nrt6)
{
}
#endif

#if IS_ENABLED(CONFIG_IPV6)
static void nsim_fib6_rt_hw_flags_set(struct nsim_fib_data *data,
const struct nsim_fib6_rt *fib6_rt,
Expand Down Expand Up @@ -667,6 +732,15 @@ static int nsim_fib6_rt_insert(struct nsim_fib_data *data,
struct nsim_fib6_rt *fib6_rt, *fib6_rt_old;
int err;

if (data->fail_route_offload) {
/* For testing purposes, user set debugfs fail_route_offload
* value to true. Simulate hardware programming latency and then
* fail.
*/
msleep(1);
return -EINVAL;
}

fib6_rt = nsim_fib6_rt_create(data, fib6_event->rt_arr,
fib6_event->nrt6);
if (IS_ERR(fib6_rt))
Expand Down Expand Up @@ -764,17 +838,21 @@ static int nsim_fib6_event(struct nsim_fib_data *data,
struct nsim_fib6_event *fib6_event,
unsigned long event)
{
int err = 0;
int err;

if (fib6_event->rt_arr[0]->fib6_src.plen)
return 0;

switch (event) {
case FIB_EVENT_ENTRY_REPLACE:
err = nsim_fib6_rt_insert(data, fib6_event);
if (err)
goto err_rt_offload_failed_flag_set;
break;
case FIB_EVENT_ENTRY_APPEND:
err = nsim_fib6_rt_append(data, fib6_event);
if (err)
goto err_rt_offload_failed_flag_set;
break;
case FIB_EVENT_ENTRY_DEL:
nsim_fib6_rt_remove(data, fib6_event);
Expand All @@ -783,6 +861,11 @@ static int nsim_fib6_event(struct nsim_fib_data *data,
break;
}

return 0;

err_rt_offload_failed_flag_set:
nsim_fib6_rt_offload_failed_flag_set(data, fib6_event->rt_arr,
fib6_event->nrt6);
return err;
}

Expand Down Expand Up @@ -1290,21 +1373,45 @@ static void nsim_fib_event_work(struct work_struct *work)
mutex_unlock(&data->fib_lock);
}

static int
nsim_fib_debugfs_init(struct nsim_fib_data *data, struct nsim_dev *nsim_dev)
{
data->ddir = debugfs_create_dir("fib", nsim_dev->ddir);
if (IS_ERR(data->ddir))
return PTR_ERR(data->ddir);

data->fail_route_offload = false;
debugfs_create_bool("fail_route_offload", 0600, data->ddir,
&data->fail_route_offload);
return 0;
}

static void nsim_fib_debugfs_exit(struct nsim_fib_data *data)
{
debugfs_remove_recursive(data->ddir);
}

struct nsim_fib_data *nsim_fib_create(struct devlink *devlink,
struct netlink_ext_ack *extack)
{
struct nsim_fib_data *data;
struct nsim_dev *nsim_dev;
int err;

data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return ERR_PTR(-ENOMEM);
data->devlink = devlink;

err = rhashtable_init(&data->nexthop_ht, &nsim_nexthop_ht_params);
nsim_dev = devlink_priv(devlink);
err = nsim_fib_debugfs_init(data, nsim_dev);
if (err)
goto err_data_free;

err = rhashtable_init(&data->nexthop_ht, &nsim_nexthop_ht_params);
if (err)
goto err_debugfs_exit;

mutex_init(&data->fib_lock);
INIT_LIST_HEAD(&data->fib_rt_list);
err = rhashtable_init(&data->fib_rt_ht, &nsim_fib_rt_ht_params);
Expand Down Expand Up @@ -1365,6 +1472,8 @@ struct nsim_fib_data *nsim_fib_create(struct devlink *devlink,
rhashtable_free_and_destroy(&data->nexthop_ht, nsim_nexthop_free,
data);
mutex_destroy(&data->fib_lock);
err_debugfs_exit:
nsim_fib_debugfs_exit(data);
err_data_free:
kfree(data);
return ERR_PTR(err);
Expand Down Expand Up @@ -1392,5 +1501,6 @@ void nsim_fib_destroy(struct devlink *devlink, struct nsim_fib_data *data)
WARN_ON_ONCE(!list_empty(&data->fib_event_queue));
WARN_ON_ONCE(!list_empty(&data->fib_rt_list));
mutex_destroy(&data->fib_lock);
nsim_fib_debugfs_exit(data);
kfree(data);
}

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