| /* |
| * net/sched/act_sample.c - Packet sampling tc action |
| * 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/string.h> |
| #include <linux/errno.h> |
| #include <linux/skbuff.h> |
| #include <linux/rtnetlink.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/gfp.h> |
| #include <net/net_namespace.h> |
| #include <net/netlink.h> |
| #include <net/pkt_sched.h> |
| #include <linux/tc_act/tc_sample.h> |
| #include <net/tc_act/tc_sample.h> |
| #include <net/psample.h> |
| |
| #include <linux/if_arp.h> |
| |
| static unsigned int sample_net_id; |
| static struct tc_action_ops act_sample_ops; |
| |
| static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = { |
| [TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) }, |
| [TCA_SAMPLE_RATE] = { .type = NLA_U32 }, |
| [TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 }, |
| [TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 }, |
| }; |
| |
| static int tcf_sample_init(struct net *net, struct nlattr *nla, |
| struct nlattr *est, struct tc_action **a, int ovr, |
| int bind, bool rtnl_held, |
| struct netlink_ext_ack *extack) |
| { |
| struct tc_action_net *tn = net_generic(net, sample_net_id); |
| struct nlattr *tb[TCA_SAMPLE_MAX + 1]; |
| struct psample_group *psample_group; |
| struct tc_sample *parm; |
| u32 psample_group_num; |
| struct tcf_sample *s; |
| bool exists = false; |
| int ret, err; |
| |
| if (!nla) |
| return -EINVAL; |
| ret = nla_parse_nested(tb, TCA_SAMPLE_MAX, nla, sample_policy, NULL); |
| if (ret < 0) |
| return ret; |
| if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || |
| !tb[TCA_SAMPLE_PSAMPLE_GROUP]) |
| return -EINVAL; |
| |
| parm = nla_data(tb[TCA_SAMPLE_PARMS]); |
| |
| err = tcf_idr_check_alloc(tn, &parm->index, a, bind); |
| if (err < 0) |
| return err; |
| exists = err; |
| if (exists && bind) |
| return 0; |
| |
| if (!exists) { |
| ret = tcf_idr_create(tn, parm->index, est, a, |
| &act_sample_ops, bind, true); |
| if (ret) { |
| tcf_idr_cleanup(tn, parm->index); |
| return ret; |
| } |
| ret = ACT_P_CREATED; |
| } else if (!ovr) { |
| tcf_idr_release(*a, bind); |
| return -EEXIST; |
| } |
| |
| psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); |
| psample_group = psample_group_get(net, psample_group_num); |
| if (!psample_group) { |
| tcf_idr_release(*a, bind); |
| return -ENOMEM; |
| } |
| |
| s = to_sample(*a); |
| |
| spin_lock_bh(&s->tcf_lock); |
| s->tcf_action = parm->action; |
| s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); |
| s->psample_group_num = psample_group_num; |
| RCU_INIT_POINTER(s->psample_group, psample_group); |
| |
| if (tb[TCA_SAMPLE_TRUNC_SIZE]) { |
| s->truncate = true; |
| s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); |
| } |
| spin_unlock_bh(&s->tcf_lock); |
| |
| if (ret == ACT_P_CREATED) |
| tcf_idr_insert(tn, *a); |
| return ret; |
| } |
| |
| static void tcf_sample_cleanup(struct tc_action *a) |
| { |
| struct tcf_sample *s = to_sample(a); |
| struct psample_group *psample_group; |
| |
| /* last reference to action, no need to lock */ |
| psample_group = rcu_dereference_protected(s->psample_group, 1); |
| RCU_INIT_POINTER(s->psample_group, NULL); |
| if (psample_group) |
| psample_group_put(psample_group); |
| } |
| |
| static bool tcf_sample_dev_ok_push(struct net_device *dev) |
| { |
| switch (dev->type) { |
| case ARPHRD_TUNNEL: |
| case ARPHRD_TUNNEL6: |
| case ARPHRD_SIT: |
| case ARPHRD_IPGRE: |
| case ARPHRD_VOID: |
| case ARPHRD_NONE: |
| return false; |
| default: |
| return true; |
| } |
| } |
| |
| static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, |
| struct tcf_result *res) |
| { |
| struct tcf_sample *s = to_sample(a); |
| struct psample_group *psample_group; |
| int retval; |
| int size; |
| int iif; |
| int oif; |
| |
| tcf_lastuse_update(&s->tcf_tm); |
| bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); |
| retval = READ_ONCE(s->tcf_action); |
| |
| psample_group = rcu_dereference_bh(s->psample_group); |
| |
| /* randomly sample packets according to rate */ |
| if (psample_group && (prandom_u32() % s->rate == 0)) { |
| if (!skb_at_tc_ingress(skb)) { |
| iif = skb->skb_iif; |
| oif = skb->dev->ifindex; |
| } else { |
| iif = skb->dev->ifindex; |
| oif = 0; |
| } |
| |
| /* on ingress, the mac header gets popped, so push it back */ |
| if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) |
| skb_push(skb, skb->mac_len); |
| |
| size = s->truncate ? s->trunc_size : skb->len; |
| psample_sample_packet(psample_group, skb, size, iif, oif, |
| s->rate); |
| |
| if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) |
| skb_pull(skb, skb->mac_len); |
| } |
| |
| return retval; |
| } |
| |
| static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, |
| int bind, int ref) |
| { |
| unsigned char *b = skb_tail_pointer(skb); |
| struct tcf_sample *s = to_sample(a); |
| struct tc_sample opt = { |
| .index = s->tcf_index, |
| .refcnt = refcount_read(&s->tcf_refcnt) - ref, |
| .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, |
| }; |
| struct tcf_t t; |
| |
| spin_lock_bh(&s->tcf_lock); |
| opt.action = s->tcf_action; |
| if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) |
| goto nla_put_failure; |
| |
| tcf_tm_dump(&t, &s->tcf_tm); |
| if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) |
| goto nla_put_failure; |
| |
| if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) |
| goto nla_put_failure; |
| |
| if (s->truncate) |
| if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) |
| goto nla_put_failure; |
| |
| if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) |
| goto nla_put_failure; |
| spin_unlock_bh(&s->tcf_lock); |
| |
| return skb->len; |
| |
| nla_put_failure: |
| spin_unlock_bh(&s->tcf_lock); |
| nlmsg_trim(skb, b); |
| return -1; |
| } |
| |
| static int tcf_sample_walker(struct net *net, struct sk_buff *skb, |
| struct netlink_callback *cb, int type, |
| const struct tc_action_ops *ops, |
| struct netlink_ext_ack *extack) |
| { |
| struct tc_action_net *tn = net_generic(net, sample_net_id); |
| |
| return tcf_generic_walker(tn, skb, cb, type, ops, extack); |
| } |
| |
| static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) |
| { |
| struct tc_action_net *tn = net_generic(net, sample_net_id); |
| |
| return tcf_idr_search(tn, a, index); |
| } |
| |
| static struct tc_action_ops act_sample_ops = { |
| .kind = "sample", |
| .id = TCA_ID_SAMPLE, |
| .owner = THIS_MODULE, |
| .act = tcf_sample_act, |
| .dump = tcf_sample_dump, |
| .init = tcf_sample_init, |
| .cleanup = tcf_sample_cleanup, |
| .walk = tcf_sample_walker, |
| .lookup = tcf_sample_search, |
| .size = sizeof(struct tcf_sample), |
| }; |
| |
| static __net_init int sample_init_net(struct net *net) |
| { |
| struct tc_action_net *tn = net_generic(net, sample_net_id); |
| |
| return tc_action_net_init(tn, &act_sample_ops); |
| } |
| |
| static void __net_exit sample_exit_net(struct list_head *net_list) |
| { |
| tc_action_net_exit(net_list, sample_net_id); |
| } |
| |
| static struct pernet_operations sample_net_ops = { |
| .init = sample_init_net, |
| .exit_batch = sample_exit_net, |
| .id = &sample_net_id, |
| .size = sizeof(struct tc_action_net), |
| }; |
| |
| static int __init sample_init_module(void) |
| { |
| return tcf_register_action(&act_sample_ops, &sample_net_ops); |
| } |
| |
| static void __exit sample_cleanup_module(void) |
| { |
| tcf_unregister_action(&act_sample_ops, &sample_net_ops); |
| } |
| |
| module_init(sample_init_module); |
| module_exit(sample_cleanup_module); |
| |
| MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); |
| MODULE_DESCRIPTION("Packet sampling action"); |
| MODULE_LICENSE("GPL v2"); |