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netdevsim: Add devlink-trap support
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Have netdevsim register its trap groups and traps with devlink during
initialization and periodically report trapped packets to devlink core.

Since netdevsim is not a real device, the trapped packets are emulated
using a workqueue that periodically reports a UDP packet with a random
5-tuple from each active packet trap and from each running netdev.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Ido Schimmel authored and David S. Miller committed Aug 17, 2019
1 parent f3047ca commit da58f90
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279 changes: 278 additions & 1 deletion drivers/net/netdevsim/dev.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,11 +17,20 @@

#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/etherdevice.h>
#include <linux/inet.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/random.h>
#include <linux/rtnetlink.h>
#include <linux/workqueue.h>
#include <net/devlink.h>
#include <net/ip.h>
#include <uapi/linux/devlink.h>
#include <uapi/linux/ip.h>
#include <uapi/linux/udp.h>

#include "netdevsim.h"

Expand Down Expand Up @@ -302,6 +311,215 @@ static void nsim_dev_dummy_region_exit(struct nsim_dev *nsim_dev)
devlink_region_destroy(nsim_dev->dummy_region);
}

struct nsim_trap_item {
void *trap_ctx;
enum devlink_trap_action action;
};

struct nsim_trap_data {
struct delayed_work trap_report_dw;
struct nsim_trap_item *trap_items_arr;
struct nsim_dev *nsim_dev;
spinlock_t trap_lock; /* Protects trap_items_arr */
};

enum {
NSIM_TRAP_ID_BASE = DEVLINK_TRAP_GENERIC_ID_MAX,
NSIM_TRAP_ID_FID_MISS,
};

#define NSIM_TRAP_NAME_FID_MISS "fid_miss"

#define NSIM_TRAP_METADATA DEVLINK_TRAP_METADATA_TYPE_F_IN_PORT

#define NSIM_TRAP_DROP(_id, _group_id) \
DEVLINK_TRAP_GENERIC(DROP, DROP, _id, \
DEVLINK_TRAP_GROUP_GENERIC(_group_id), \
NSIM_TRAP_METADATA)
#define NSIM_TRAP_EXCEPTION(_id, _group_id) \
DEVLINK_TRAP_GENERIC(EXCEPTION, TRAP, _id, \
DEVLINK_TRAP_GROUP_GENERIC(_group_id), \
NSIM_TRAP_METADATA)
#define NSIM_TRAP_DRIVER_EXCEPTION(_id, _group_id) \
DEVLINK_TRAP_DRIVER(EXCEPTION, TRAP, NSIM_TRAP_ID_##_id, \
NSIM_TRAP_NAME_##_id, \
DEVLINK_TRAP_GROUP_GENERIC(_group_id), \
NSIM_TRAP_METADATA)

static const struct devlink_trap nsim_traps_arr[] = {
NSIM_TRAP_DROP(SMAC_MC, L2_DROPS),
NSIM_TRAP_DROP(VLAN_TAG_MISMATCH, L2_DROPS),
NSIM_TRAP_DROP(INGRESS_VLAN_FILTER, L2_DROPS),
NSIM_TRAP_DROP(INGRESS_STP_FILTER, L2_DROPS),
NSIM_TRAP_DROP(EMPTY_TX_LIST, L2_DROPS),
NSIM_TRAP_DROP(PORT_LOOPBACK_FILTER, L2_DROPS),
NSIM_TRAP_DRIVER_EXCEPTION(FID_MISS, L2_DROPS),
NSIM_TRAP_DROP(BLACKHOLE_ROUTE, L3_DROPS),
NSIM_TRAP_EXCEPTION(TTL_ERROR, L3_DROPS),
NSIM_TRAP_DROP(TAIL_DROP, BUFFER_DROPS),
};

#define NSIM_TRAP_L4_DATA_LEN 100

static struct sk_buff *nsim_dev_trap_skb_build(void)
{
int tot_len, data_len = NSIM_TRAP_L4_DATA_LEN;
struct sk_buff *skb;
struct udphdr *udph;
struct ethhdr *eth;
struct iphdr *iph;

skb = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
if (!skb)
return NULL;
tot_len = sizeof(struct iphdr) + sizeof(struct udphdr) + data_len;

eth = skb_put(skb, sizeof(struct ethhdr));
eth_random_addr(eth->h_dest);
eth_random_addr(eth->h_source);
eth->h_proto = htons(ETH_P_IP);
skb->protocol = htons(ETH_P_IP);

iph = skb_put(skb, sizeof(struct iphdr));
iph->protocol = IPPROTO_UDP;
iph->saddr = in_aton("192.0.2.1");
iph->daddr = in_aton("198.51.100.1");
iph->version = 0x4;
iph->frag_off = 0;
iph->ihl = 0x5;
iph->tot_len = htons(tot_len);
iph->ttl = 100;
ip_send_check(iph);

udph = skb_put_zero(skb, sizeof(struct udphdr) + data_len);
get_random_bytes(&udph->source, sizeof(u16));
get_random_bytes(&udph->dest, sizeof(u16));
udph->len = htons(sizeof(struct udphdr) + data_len);

return skb;
}

static void nsim_dev_trap_report(struct nsim_dev_port *nsim_dev_port)
{
struct nsim_dev *nsim_dev = nsim_dev_port->ns->nsim_dev;
struct devlink *devlink = priv_to_devlink(nsim_dev);
struct nsim_trap_data *nsim_trap_data;
int i;

nsim_trap_data = nsim_dev->trap_data;

spin_lock(&nsim_trap_data->trap_lock);
for (i = 0; i < ARRAY_SIZE(nsim_traps_arr); i++) {
struct nsim_trap_item *nsim_trap_item;
struct sk_buff *skb;

nsim_trap_item = &nsim_trap_data->trap_items_arr[i];
if (nsim_trap_item->action == DEVLINK_TRAP_ACTION_DROP)
continue;

skb = nsim_dev_trap_skb_build();
if (!skb)
continue;
skb->dev = nsim_dev_port->ns->netdev;

/* Trapped packets are usually passed to devlink in softIRQ,
* but in this case they are generated in a workqueue. Disable
* softIRQs to prevent lockdep from complaining about
* "incosistent lock state".
*/
local_bh_disable();
devlink_trap_report(devlink, skb, nsim_trap_item->trap_ctx,
&nsim_dev_port->devlink_port);
local_bh_enable();
consume_skb(skb);
}
spin_unlock(&nsim_trap_data->trap_lock);
}

#define NSIM_TRAP_REPORT_INTERVAL_MS 100

static void nsim_dev_trap_report_work(struct work_struct *work)
{
struct nsim_trap_data *nsim_trap_data;
struct nsim_dev_port *nsim_dev_port;
struct nsim_dev *nsim_dev;

nsim_trap_data = container_of(work, struct nsim_trap_data,
trap_report_dw.work);
nsim_dev = nsim_trap_data->nsim_dev;

/* For each running port and enabled packet trap, generate a UDP
* packet with a random 5-tuple and report it.
*/
mutex_lock(&nsim_dev->port_list_lock);
list_for_each_entry(nsim_dev_port, &nsim_dev->port_list, list) {
if (!netif_running(nsim_dev_port->ns->netdev))
continue;

nsim_dev_trap_report(nsim_dev_port);
}
mutex_unlock(&nsim_dev->port_list_lock);

schedule_delayed_work(&nsim_dev->trap_data->trap_report_dw,
msecs_to_jiffies(NSIM_TRAP_REPORT_INTERVAL_MS));
}

static int nsim_dev_traps_init(struct devlink *devlink)
{
struct nsim_dev *nsim_dev = devlink_priv(devlink);
struct nsim_trap_data *nsim_trap_data;
int err;

nsim_trap_data = kzalloc(sizeof(*nsim_trap_data), GFP_KERNEL);
if (!nsim_trap_data)
return -ENOMEM;

nsim_trap_data->trap_items_arr = kcalloc(ARRAY_SIZE(nsim_traps_arr),
sizeof(struct nsim_trap_item),
GFP_KERNEL);
if (!nsim_trap_data->trap_items_arr) {
err = -ENOMEM;
goto err_trap_data_free;
}

/* The lock is used to protect the action state of the registered
* traps. The value is written by user and read in delayed work when
* iterating over all the traps.
*/
spin_lock_init(&nsim_trap_data->trap_lock);
nsim_trap_data->nsim_dev = nsim_dev;
nsim_dev->trap_data = nsim_trap_data;

err = devlink_traps_register(devlink, nsim_traps_arr,
ARRAY_SIZE(nsim_traps_arr), NULL);
if (err)
goto err_trap_items_free;

INIT_DELAYED_WORK(&nsim_dev->trap_data->trap_report_dw,
nsim_dev_trap_report_work);
schedule_delayed_work(&nsim_dev->trap_data->trap_report_dw,
msecs_to_jiffies(NSIM_TRAP_REPORT_INTERVAL_MS));

return 0;

err_trap_items_free:
kfree(nsim_trap_data->trap_items_arr);
err_trap_data_free:
kfree(nsim_trap_data);
return err;
}

static void nsim_dev_traps_exit(struct devlink *devlink)
{
struct nsim_dev *nsim_dev = devlink_priv(devlink);

cancel_delayed_work_sync(&nsim_dev->trap_data->trap_report_dw);
devlink_traps_unregister(devlink, nsim_traps_arr,
ARRAY_SIZE(nsim_traps_arr));
kfree(nsim_dev->trap_data->trap_items_arr);
kfree(nsim_dev->trap_data);
}

static int nsim_dev_reload(struct devlink *devlink,
struct netlink_ext_ack *extack)
{
Expand Down Expand Up @@ -369,9 +587,61 @@ static int nsim_dev_flash_update(struct devlink *devlink, const char *file_name,
return 0;
}

static struct nsim_trap_item *
nsim_dev_trap_item_lookup(struct nsim_dev *nsim_dev, u16 trap_id)
{
struct nsim_trap_data *nsim_trap_data = nsim_dev->trap_data;
int i;

for (i = 0; i < ARRAY_SIZE(nsim_traps_arr); i++) {
if (nsim_traps_arr[i].id == trap_id)
return &nsim_trap_data->trap_items_arr[i];
}

return NULL;
}

static int nsim_dev_devlink_trap_init(struct devlink *devlink,
const struct devlink_trap *trap,
void *trap_ctx)
{
struct nsim_dev *nsim_dev = devlink_priv(devlink);
struct nsim_trap_item *nsim_trap_item;

nsim_trap_item = nsim_dev_trap_item_lookup(nsim_dev, trap->id);
if (WARN_ON(!nsim_trap_item))
return -ENOENT;

nsim_trap_item->trap_ctx = trap_ctx;
nsim_trap_item->action = trap->init_action;

return 0;
}

static int
nsim_dev_devlink_trap_action_set(struct devlink *devlink,
const struct devlink_trap *trap,
enum devlink_trap_action action)
{
struct nsim_dev *nsim_dev = devlink_priv(devlink);
struct nsim_trap_item *nsim_trap_item;

nsim_trap_item = nsim_dev_trap_item_lookup(nsim_dev, trap->id);
if (WARN_ON(!nsim_trap_item))
return -ENOENT;

spin_lock(&nsim_dev->trap_data->trap_lock);
nsim_trap_item->action = action;
spin_unlock(&nsim_dev->trap_data->trap_lock);

return 0;
}

static const struct devlink_ops nsim_dev_devlink_ops = {
.reload = nsim_dev_reload,
.flash_update = nsim_dev_flash_update,
.trap_init = nsim_dev_devlink_trap_init,
.trap_action_set = nsim_dev_devlink_trap_action_set,
};

#define NSIM_DEV_MAX_MACS_DEFAULT 32
Expand Down Expand Up @@ -421,10 +691,14 @@ nsim_dev_create(struct nsim_bus_dev *nsim_bus_dev, unsigned int port_count)
if (err)
goto err_params_unregister;

err = nsim_dev_debugfs_init(nsim_dev);
err = nsim_dev_traps_init(devlink);
if (err)
goto err_dummy_region_exit;

err = nsim_dev_debugfs_init(nsim_dev);
if (err)
goto err_traps_exit;

err = nsim_bpf_dev_init(nsim_dev);
if (err)
goto err_debugfs_exit;
Expand All @@ -434,6 +708,8 @@ nsim_dev_create(struct nsim_bus_dev *nsim_bus_dev, unsigned int port_count)

err_debugfs_exit:
nsim_dev_debugfs_exit(nsim_dev);
err_traps_exit:
nsim_dev_traps_exit(devlink);
err_dummy_region_exit:
nsim_dev_dummy_region_exit(nsim_dev);
err_params_unregister:
Expand All @@ -456,6 +732,7 @@ static void nsim_dev_destroy(struct nsim_dev *nsim_dev)

nsim_bpf_dev_exit(nsim_dev);
nsim_dev_debugfs_exit(nsim_dev);
nsim_dev_traps_exit(devlink);
nsim_dev_dummy_region_exit(nsim_dev);
devlink_params_unregister(devlink, nsim_devlink_params,
ARRAY_SIZE(nsim_devlink_params));
Expand Down
1 change: 1 addition & 0 deletions drivers/net/netdevsim/netdevsim.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -145,6 +145,7 @@ struct nsim_dev_port {
struct nsim_dev {
struct nsim_bus_dev *nsim_bus_dev;
struct nsim_fib_data *fib_data;
struct nsim_trap_data *trap_data;
struct dentry *ddir;
struct dentry *ports_ddir;
struct bpf_offload_dev *bpf_dev;
Expand Down

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