1 // SPDX-License-Identifier: GPL-2.0-only
3 * net/psample/psample.c - Netlink channel for packet sampling
4 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
7 #include <linux/types.h>
8 #include <linux/kernel.h>
9 #include <linux/skbuff.h>
10 #include <linux/module.h>
11 #include <net/net_namespace.h>
13 #include <net/netlink.h>
14 #include <net/genetlink.h>
15 #include <net/psample.h>
16 #include <linux/spinlock.h>
18 #define PSAMPLE_MAX_PACKET_SIZE 0xffff
20 static LIST_HEAD(psample_groups_list);
21 static DEFINE_SPINLOCK(psample_groups_lock);
23 /* multicast groups */
24 enum psample_nl_multicast_groups {
25 PSAMPLE_NL_MCGRP_CONFIG,
26 PSAMPLE_NL_MCGRP_SAMPLE,
29 static const struct genl_multicast_group psample_nl_mcgrps[] = {
30 [PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME },
31 [PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME },
34 static struct genl_family psample_nl_family __ro_after_init;
36 static int psample_group_nl_fill(struct sk_buff *msg,
37 struct psample_group *group,
38 enum psample_command cmd, u32 portid, u32 seq,
44 hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd);
48 ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
52 ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount);
56 ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq);
60 genlmsg_end(msg, hdr);
64 genlmsg_cancel(msg, hdr);
68 static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg,
69 struct netlink_callback *cb)
71 struct psample_group *group;
72 int start = cb->args[0];
76 spin_lock_bh(&psample_groups_lock);
77 list_for_each_entry(group, &psample_groups_list, list) {
78 if (!net_eq(group->net, sock_net(msg->sk)))
84 err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP,
85 NETLINK_CB(cb->skb).portid,
86 cb->nlh->nlmsg_seq, NLM_F_MULTI);
92 spin_unlock_bh(&psample_groups_lock);
97 static const struct genl_ops psample_nl_ops[] = {
99 .cmd = PSAMPLE_CMD_GET_GROUP,
100 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
101 .dumpit = psample_nl_cmd_get_group_dumpit,
102 /* can be retrieved by unprivileged users */
106 static struct genl_family psample_nl_family __ro_after_init = {
107 .name = PSAMPLE_GENL_NAME,
108 .version = PSAMPLE_GENL_VERSION,
109 .maxattr = PSAMPLE_ATTR_MAX,
111 .module = THIS_MODULE,
112 .mcgrps = psample_nl_mcgrps,
113 .ops = psample_nl_ops,
114 .n_ops = ARRAY_SIZE(psample_nl_ops),
115 .n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps),
118 static void psample_group_notify(struct psample_group *group,
119 enum psample_command cmd)
124 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
128 err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
130 genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
131 PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
136 static struct psample_group *psample_group_create(struct net *net,
139 struct psample_group *group;
141 group = kzalloc(sizeof(*group), GFP_ATOMIC);
146 group->group_num = group_num;
147 list_add_tail(&group->list, &psample_groups_list);
149 psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
153 static void psample_group_destroy(struct psample_group *group)
155 psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
156 list_del(&group->list);
157 kfree_rcu(group, rcu);
160 static struct psample_group *
161 psample_group_lookup(struct net *net, u32 group_num)
163 struct psample_group *group;
165 list_for_each_entry(group, &psample_groups_list, list)
166 if ((group->group_num == group_num) && (group->net == net))
171 struct psample_group *psample_group_get(struct net *net, u32 group_num)
173 struct psample_group *group;
175 spin_lock_bh(&psample_groups_lock);
177 group = psample_group_lookup(net, group_num);
179 group = psample_group_create(net, group_num);
186 spin_unlock_bh(&psample_groups_lock);
189 EXPORT_SYMBOL_GPL(psample_group_get);
191 void psample_group_take(struct psample_group *group)
193 spin_lock_bh(&psample_groups_lock);
195 spin_unlock_bh(&psample_groups_lock);
197 EXPORT_SYMBOL_GPL(psample_group_take);
199 void psample_group_put(struct psample_group *group)
201 spin_lock_bh(&psample_groups_lock);
203 if (--group->refcount == 0)
204 psample_group_destroy(group);
206 spin_unlock_bh(&psample_groups_lock);
208 EXPORT_SYMBOL_GPL(psample_group_put);
210 void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
211 u32 trunc_size, int in_ifindex, int out_ifindex,
214 struct sk_buff *nl_skb;
220 meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
221 (out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
222 nla_total_size(sizeof(u32)) + /* sample_rate */
223 nla_total_size(sizeof(u32)) + /* orig_size */
224 nla_total_size(sizeof(u32)) + /* group_num */
225 nla_total_size(sizeof(u32)); /* seq */
227 data_len = min(skb->len, trunc_size);
228 if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
229 data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
232 nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC);
233 if (unlikely(!nl_skb))
236 data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
242 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
243 if (unlikely(ret < 0))
248 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
249 if (unlikely(ret < 0))
253 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
254 if (unlikely(ret < 0))
257 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
258 if (unlikely(ret < 0))
261 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
262 if (unlikely(ret < 0))
265 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
266 if (unlikely(ret < 0))
270 int nla_len = nla_total_size(data_len);
273 nla = skb_put(nl_skb, nla_len);
274 nla->nla_type = PSAMPLE_ATTR_DATA;
275 nla->nla_len = nla_attr_size(data_len);
277 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
281 genlmsg_end(nl_skb, data);
282 genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
283 PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);
287 pr_err_ratelimited("Could not create psample log message\n");
290 EXPORT_SYMBOL_GPL(psample_sample_packet);
292 static int __init psample_module_init(void)
294 return genl_register_family(&psample_nl_family);
297 static void __exit psample_module_exit(void)
299 genl_unregister_family(&psample_nl_family);
302 module_init(psample_module_init);
303 module_exit(psample_module_exit);
305 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
306 MODULE_DESCRIPTION("netlink channel for packet sampling");
307 MODULE_LICENSE("GPL v2");