2 files changed, 282 insertions, 1 deletions

diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index a570da406d1d..c217049552f7 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -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"
 
@@ -302,6 +311,218 @@ 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 */
+};
+
+/* All driver-specific traps must be documented in
+ * Documentation/networking/devlink-trap-netdevsim.rst
+ */
+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)
 {
@@ -369,9 +590,61 @@ 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
@@ -421,10 +694,14 @@ 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;
@@ -434,6 +711,8 @@ 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:
@@ -456,6 +735,7 @@ 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));
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index 4c758c6919f5..262a6978bbca 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -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;