Merge branch 'psample-Add-additional-metadata-attributes'

Ido Schimmel says:

====================
psample: Add additional metadata attributes

This series extends the psample module to expose additional metadata to
user space for packets sampled via act_sample. The new metadata (e.g.,
transit delay) can then be consumed by applications such as hsflowd [1]
for better network observability.

netdevsim is extended with a dummy psample implementation that
periodically reports "sampled" packets to the psample module. In
addition to testing of the psample module, it enables the development
and demonstration of user space applications (e.g., hsflowd) that are
interested in the new metadata even without access to specialized
hardware (e.g., Spectrum ASIC) that can provide it.

mlxsw is also extended to provide the new metadata to psample.

A Wireshark dissector for psample netlink packets [2] will be submitted
upstream after the kernel patches are accepted. In addition, a libpcap
capture module for psample is currently in the works. Eventually, users
should be able to run:

 # tshark -i psample

In order to consume sampled packets along with their metadata.

Series overview:

Patch #1 makes it easier to extend the metadata provided to psample

Patch #2 adds the new metadata attributes to psample

Patch #3 extends netdevsim to periodically report "sampled" packets to
psample. Various debugfs knobs are added to control the reporting

Patch #4 adds a selftest over netdevsim

Patches #5-#10 gradually add support for the new metadata in mlxsw

Patch #11 adds a selftest over mlxsw

[1] https://sflow.org/draft4_sflow_transit.txt
[2] https://gitlab.com/amitcohen1/wireshark/-/commit/3d711143024e032aef1b056dd23f0266c54fab56
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 264 insertions, 0 deletions

diff --git a/drivers/net/netdevsim/psample.c b/drivers/net/netdevsim/psample.c
new file mode 100644
index 000000000000..5ec3bd7f891b
--- /dev/null
+++ b/drivers/net/netdevsim/psample.c
@@ -0,0 +1,264 @@
+// 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)
+{
+	md->trunc_size = psample->trunc_size;
+	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);
+	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);
+}