--- /dev/null
+/*
+ * net/psample/psample.c - Netlink channel for packet sampling
+ * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/module.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+#include <net/psample.h>
+#include <linux/spinlock.h>
+
+#define PSAMPLE_MAX_PACKET_SIZE 0xffff
+
+static LIST_HEAD(psample_groups_list);
+static DEFINE_SPINLOCK(psample_groups_lock);
+
+/* multicast groups */
+enum psample_nl_multicast_groups {
+ PSAMPLE_NL_MCGRP_CONFIG,
+ PSAMPLE_NL_MCGRP_SAMPLE,
+};
+
+static const struct genl_multicast_group psample_nl_mcgrps[] = {
+ [PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME },
+ [PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME },
+};
+
+static struct genl_family psample_nl_family __ro_after_init;
+
+static int psample_group_nl_fill(struct sk_buff *msg,
+ struct psample_group *group,
+ enum psample_command cmd, u32 portid, u32 seq,
+ int flags)
+{
+ void *hdr;
+ int ret;
+
+ hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd);
+ if (!hdr)
+ return -EMSGSIZE;
+
+ ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
+ if (ret < 0)
+ goto error;
+
+ ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount);
+ if (ret < 0)
+ goto error;
+
+ ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq);
+ if (ret < 0)
+ goto error;
+
+ genlmsg_end(msg, hdr);
+ return 0;
+
+error:
+ genlmsg_cancel(msg, hdr);
+ return -EMSGSIZE;
+}
+
+static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg,
+ struct netlink_callback *cb)
+{
+ struct psample_group *group;
+ int start = cb->args[0];
+ int idx = 0;
+ int err;
+
+ spin_lock(&psample_groups_lock);
+ list_for_each_entry(group, &psample_groups_list, list) {
+ if (!net_eq(group->net, sock_net(msg->sk)))
+ continue;
+ if (idx < start) {
+ idx++;
+ continue;
+ }
+ err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP,
+ NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq, NLM_F_MULTI);
+ if (err)
+ break;
+ idx++;
+ }
+
+ spin_unlock(&psample_groups_lock);
+ cb->args[0] = idx;
+ return msg->len;
+}
+
+static const struct genl_ops psample_nl_ops[] = {
+ {
+ .cmd = PSAMPLE_CMD_GET_GROUP,
+ .dumpit = psample_nl_cmd_get_group_dumpit,
+ /* can be retrieved by unprivileged users */
+ }
+};
+
+static struct genl_family psample_nl_family __ro_after_init = {
+ .name = PSAMPLE_GENL_NAME,
+ .version = PSAMPLE_GENL_VERSION,
+ .maxattr = PSAMPLE_ATTR_MAX,
+ .netnsok = true,
+ .module = THIS_MODULE,
+ .mcgrps = psample_nl_mcgrps,
+ .ops = psample_nl_ops,
+ .n_ops = ARRAY_SIZE(psample_nl_ops),
+ .n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps),
+};
+
+static void psample_group_notify(struct psample_group *group,
+ enum psample_command cmd)
+{
+ struct sk_buff *msg;
+ int err;
+
+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+ if (!msg)
+ return;
+
+ err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
+ if (!err)
+ genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
+ PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
+ else
+ nlmsg_free(msg);
+}
+
+static struct psample_group *psample_group_create(struct net *net,
+ u32 group_num)
+{
+ struct psample_group *group;
+
+ group = kzalloc(sizeof(*group), GFP_ATOMIC);
+ if (!group)
+ return NULL;
+
+ group->net = net;
+ group->group_num = group_num;
+ list_add_tail(&group->list, &psample_groups_list);
+
+ psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
+ return group;
+}
+
+static void psample_group_destroy(struct psample_group *group)
+{
+ psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
+ list_del(&group->list);
+ kfree(group);
+}
+
+static struct psample_group *
+psample_group_lookup(struct net *net, u32 group_num)
+{
+ struct psample_group *group;
+
+ list_for_each_entry(group, &psample_groups_list, list)
+ if ((group->group_num == group_num) && (group->net == net))
+ return group;
+ return NULL;
+}
+
+struct psample_group *psample_group_get(struct net *net, u32 group_num)
+{
+ struct psample_group *group;
+
+ spin_lock(&psample_groups_lock);
+
+ group = psample_group_lookup(net, group_num);
+ if (!group) {
+ group = psample_group_create(net, group_num);
+ if (!group)
+ goto out;
+ }
+ group->refcount++;
+
+out:
+ spin_unlock(&psample_groups_lock);
+ return group;
+}
+EXPORT_SYMBOL_GPL(psample_group_get);
+
+void psample_group_put(struct psample_group *group)
+{
+ spin_lock(&psample_groups_lock);
+
+ if (--group->refcount == 0)
+ psample_group_destroy(group);
+
+ spin_unlock(&psample_groups_lock);
+}
+EXPORT_SYMBOL_GPL(psample_group_put);
+
+void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
+ u32 trunc_size, int in_ifindex, int out_ifindex,
+ u32 sample_rate)
+{
+ struct sk_buff *nl_skb;
+ int data_len;
+ int meta_len;
+ void *data;
+ int ret;
+
+ meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
+ (out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
+ nla_total_size(sizeof(u32)) + /* sample_rate */
+ nla_total_size(sizeof(u32)) + /* orig_size */
+ nla_total_size(sizeof(u32)) + /* group_num */
+ nla_total_size(sizeof(u32)); /* seq */
+
+ data_len = min(skb->len, trunc_size);
+ if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
+ data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
+ - NLA_ALIGNTO;
+
+ nl_skb = genlmsg_new(meta_len + data_len, GFP_ATOMIC);
+ if (unlikely(!nl_skb))
+ return;
+
+ data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
+ PSAMPLE_CMD_SAMPLE);
+ if (unlikely(!data))
+ goto error;
+
+ if (in_ifindex) {
+ ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
+ if (unlikely(ret < 0))
+ goto error;
+ }
+
+ if (out_ifindex) {
+ ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
+ if (unlikely(ret < 0))
+ goto error;
+ }
+
+ ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
+ if (unlikely(ret < 0))
+ goto error;
+
+ ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
+ if (unlikely(ret < 0))
+ goto error;
+
+ ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
+ if (unlikely(ret < 0))
+ goto error;
+
+ ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
+ if (unlikely(ret < 0))
+ goto error;
+
+ if (data_len) {
+ int nla_len = nla_total_size(data_len);
+ struct nlattr *nla;
+
+ nla = (struct nlattr *)skb_put(nl_skb, nla_len);
+ nla->nla_type = PSAMPLE_ATTR_DATA;
+ nla->nla_len = nla_attr_size(data_len);
+
+ if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
+ goto error;
+ }
+
+ genlmsg_end(nl_skb, data);
+ genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
+ PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);
+
+ return;
+error:
+ pr_err_ratelimited("Could not create psample log message\n");
+ nlmsg_free(nl_skb);
+}
+EXPORT_SYMBOL_GPL(psample_sample_packet);
+
+static int __init psample_module_init(void)
+{
+ return genl_register_family(&psample_nl_family);
+}
+
+static void __exit psample_module_exit(void)
+{
+ genl_unregister_family(&psample_nl_family);
+}
+
+module_init(psample_module_init);
+module_exit(psample_module_exit);
+
+MODULE_AUTHOR("Yotam Gigi <yotamg@mellanox.com>");
+MODULE_DESCRIPTION("netlink channel for packet sampling");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-rpi.git / commitdiff