Quelle  psample.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Mellanox Technologies. All rights reserved */

#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/etherdevice.h>
#include <linux/inet.h>
#include <linux/kernel.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <net/devlink.h>
#include <net/ip.h>
#include <net/psample.h>
#include <uapi/linux/ip.h>
#include <uapi/linux/udp.h>

#include "netdevsim.h"

#define NSIM_PSAMPLE_REPORT_INTERVAL_MS 100
#define NSIM_PSAMPLE_INVALID_TC  0xFFFF
#define NSIM_PSAMPLE_L4_DATA_LEN 100

struct nsim_dev_psample {
 struct delayed_work psample_dw;
 struct dentry *ddir;
 struct psample_group *group;
 u32 rate;
 u32 group_num;
 u32 trunc_size;
 int in_ifindex;
 int out_ifindex;
 u16 out_tc;
 u64 out_tc_occ_max;
 u64 latency_max;
 bool is_active;
};

static struct sk_buff *nsim_dev_psample_skb_build(void)
{
 int tot_len, data_len = NSIM_PSAMPLE_L4_DATA_LEN;
 struct sk_buff *skb;
 struct udphdr *udph;
 struct ethhdr *eth;
 struct iphdr *iph;

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

 skb_reset_mac_header(skb);
 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);

 skb_set_network_header(skb, skb->len);
 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->id = 0;
 iph->ttl = 100;
 iph->check = 0;
 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);

 skb_set_transport_header(skb, skb->len);
 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_psample_md_prepare(const struct nsim_dev_psample *psample,
     struct psample_metadata *md,
     unsigned int len)
{
 md->trunc_size = psample->trunc_size ? psample->trunc_size : len;
 md->in_ifindex = psample->in_ifindex;
 md->out_ifindex = psample->out_ifindex;

 if (psample->out_tc != NSIM_PSAMPLE_INVALID_TC) {
  md->out_tc = psample->out_tc;
  md->out_tc_valid = 1;
 }

 if (psample->out_tc_occ_max) {
  u64 out_tc_occ;

  get_random_bytes(&out_tc_occ, sizeof(u64));
  md->out_tc_occ = out_tc_occ & (psample->out_tc_occ_max - 1);
  md->out_tc_occ_valid = 1;
 }

 if (psample->latency_max) {
  u64 latency;

  get_random_bytes(&latency, sizeof(u64));
  md->latency = latency & (psample->latency_max - 1);
  md->latency_valid = 1;
 }
}

static void nsim_dev_psample_report_work(struct work_struct *work)
{
 struct nsim_dev_psample *psample;
 struct psample_metadata md = {};
 struct sk_buff *skb;
 unsigned long delay;

 psample = container_of(work, struct nsim_dev_psample, psample_dw.work);

 skb = nsim_dev_psample_skb_build();
 if (!skb)
  goto out;

 nsim_dev_psample_md_prepare(psample, &md, skb->len);
 psample_sample_packet(psample->group, skb, psample->rate, &md);
 consume_skb(skb);

out:
 delay = msecs_to_jiffies(NSIM_PSAMPLE_REPORT_INTERVAL_MS);
 schedule_delayed_work(&psample->psample_dw, delay);
}

static int nsim_dev_psample_enable(struct nsim_dev *nsim_dev)
{
 struct nsim_dev_psample *psample = nsim_dev->psample;
 struct devlink *devlink;
 unsigned long delay;

 if (psample->is_active)
  return -EBUSY;

 devlink = priv_to_devlink(nsim_dev);
 psample->group = psample_group_get(devlink_net(devlink),
        psample->group_num);
 if (!psample->group)
  return -EINVAL;

 delay = msecs_to_jiffies(NSIM_PSAMPLE_REPORT_INTERVAL_MS);
 schedule_delayed_work(&psample->psample_dw, delay);

 psample->is_active = true;

 return 0;
}

static int nsim_dev_psample_disable(struct nsim_dev *nsim_dev)
{
 struct nsim_dev_psample *psample = nsim_dev->psample;

 if (!psample->is_active)
  return -EINVAL;

 psample->is_active = false;

 cancel_delayed_work_sync(&psample->psample_dw);
 psample_group_put(psample->group);

 return 0;
}

static ssize_t nsim_dev_psample_enable_write(struct file *file,
          const char __user *data,
          size_t count, loff_t *ppos)
{
 struct nsim_dev *nsim_dev = file->private_data;
 bool enable;
 int err;

 err = kstrtobool_from_user(data, count, &enable);
 if (err)
  return err;

 if (enable)
  err = nsim_dev_psample_enable(nsim_dev);
 else
  err = nsim_dev_psample_disable(nsim_dev);

 return err ? err : count;
}

static const struct file_operations nsim_psample_enable_fops = {
 .open = simple_open,
 .write = nsim_dev_psample_enable_write,
 .llseek = generic_file_llseek,
 .owner = THIS_MODULE,
};

int nsim_dev_psample_init(struct nsim_dev *nsim_dev)
{
 struct nsim_dev_psample *psample;
 int err;

 psample = kzalloc(sizeof(*psample), GFP_KERNEL);
 if (!psample)
  return -ENOMEM;
 nsim_dev->psample = psample;

 INIT_DELAYED_WORK(&psample->psample_dw, nsim_dev_psample_report_work);

 psample->ddir = debugfs_create_dir("psample", nsim_dev->ddir);
 if (IS_ERR(psample->ddir)) {
  err = PTR_ERR(psample->ddir);
  goto err_psample_free;
 }

 /* Populate sampling parameters with sane defaults. */
 psample->rate = 100;
 debugfs_create_u32("rate", 0600, psample->ddir, &psample->rate);

 psample->group_num = 10;
 debugfs_create_u32("group_num", 0600, psample->ddir,
      &psample->group_num);

 psample->trunc_size = 0;
 debugfs_create_u32("trunc_size", 0600, psample->ddir,
      &psample->trunc_size);

 psample->in_ifindex = 1;
 debugfs_create_u32("in_ifindex", 0600, psample->ddir,
      &psample->in_ifindex);

 psample->out_ifindex = 2;
 debugfs_create_u32("out_ifindex", 0600, psample->ddir,
      &psample->out_ifindex);

 psample->out_tc = 0;
 debugfs_create_u16("out_tc", 0600, psample->ddir, &psample->out_tc);

 psample->out_tc_occ_max = 10000;
 debugfs_create_u64("out_tc_occ_max", 0600, psample->ddir,
      &psample->out_tc_occ_max);

 psample->latency_max = 50;
 debugfs_create_u64("latency_max", 0600, psample->ddir,
      &psample->latency_max);

 debugfs_create_file("enable", 0200, psample->ddir, nsim_dev,
       &nsim_psample_enable_fops);

 return 0;

err_psample_free:
 kfree(nsim_dev->psample);
 return err;
}

void nsim_dev_psample_exit(struct nsim_dev *nsim_dev)
{
 debugfs_remove_recursive(nsim_dev->psample->ddir);
 if (nsim_dev->psample->is_active) {
  cancel_delayed_work_sync(&nsim_dev->psample->psample_dw);
  psample_group_put(nsim_dev->psample->group);
 }
 kfree(nsim_dev->psample);
}