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326 lines
8.1 KiB
326 lines
8.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* net/sched/act_sample.c - Packet sampling tc action |
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* Copyright (c) 2017 Yotam Gigi <[email protected]> |
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*/ |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/string.h> |
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#include <linux/errno.h> |
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#include <linux/skbuff.h> |
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#include <linux/rtnetlink.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/gfp.h> |
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#include <net/net_namespace.h> |
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#include <net/netlink.h> |
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#include <net/pkt_sched.h> |
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#include <linux/tc_act/tc_sample.h> |
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#include <net/tc_act/tc_sample.h> |
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#include <net/psample.h> |
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#include <net/pkt_cls.h> |
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#include <linux/if_arp.h> |
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static unsigned int sample_net_id; |
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static struct tc_action_ops act_sample_ops; |
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static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = { |
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[TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) }, |
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[TCA_SAMPLE_RATE] = { .type = NLA_U32 }, |
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[TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 }, |
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[TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 }, |
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}; |
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static int tcf_sample_init(struct net *net, struct nlattr *nla, |
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struct nlattr *est, struct tc_action **a, int ovr, |
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int bind, bool rtnl_held, struct tcf_proto *tp, |
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u32 flags, struct netlink_ext_ack *extack) |
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{ |
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struct tc_action_net *tn = net_generic(net, sample_net_id); |
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struct nlattr *tb[TCA_SAMPLE_MAX + 1]; |
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struct psample_group *psample_group; |
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u32 psample_group_num, rate, index; |
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struct tcf_chain *goto_ch = NULL; |
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struct tc_sample *parm; |
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struct tcf_sample *s; |
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bool exists = false; |
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int ret, err; |
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if (!nla) |
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return -EINVAL; |
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ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla, |
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sample_policy, NULL); |
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if (ret < 0) |
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return ret; |
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if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] || |
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!tb[TCA_SAMPLE_PSAMPLE_GROUP]) |
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return -EINVAL; |
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parm = nla_data(tb[TCA_SAMPLE_PARMS]); |
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index = parm->index; |
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err = tcf_idr_check_alloc(tn, &index, a, bind); |
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if (err < 0) |
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return err; |
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exists = err; |
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if (exists && bind) |
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return 0; |
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if (!exists) { |
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ret = tcf_idr_create(tn, index, est, a, |
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&act_sample_ops, bind, true, 0); |
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if (ret) { |
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tcf_idr_cleanup(tn, index); |
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return ret; |
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} |
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ret = ACT_P_CREATED; |
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} else if (!ovr) { |
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tcf_idr_release(*a, bind); |
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return -EEXIST; |
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} |
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err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); |
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if (err < 0) |
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goto release_idr; |
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rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); |
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if (!rate) { |
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NL_SET_ERR_MSG(extack, "invalid sample rate"); |
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err = -EINVAL; |
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goto put_chain; |
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} |
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psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); |
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psample_group = psample_group_get(net, psample_group_num); |
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if (!psample_group) { |
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err = -ENOMEM; |
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goto put_chain; |
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} |
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s = to_sample(*a); |
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spin_lock_bh(&s->tcf_lock); |
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goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); |
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s->rate = rate; |
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s->psample_group_num = psample_group_num; |
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psample_group = rcu_replace_pointer(s->psample_group, psample_group, |
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lockdep_is_held(&s->tcf_lock)); |
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if (tb[TCA_SAMPLE_TRUNC_SIZE]) { |
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s->truncate = true; |
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s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); |
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} |
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spin_unlock_bh(&s->tcf_lock); |
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if (psample_group) |
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psample_group_put(psample_group); |
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if (goto_ch) |
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tcf_chain_put_by_act(goto_ch); |
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return ret; |
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put_chain: |
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if (goto_ch) |
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tcf_chain_put_by_act(goto_ch); |
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release_idr: |
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tcf_idr_release(*a, bind); |
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return err; |
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} |
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static void tcf_sample_cleanup(struct tc_action *a) |
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{ |
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struct tcf_sample *s = to_sample(a); |
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struct psample_group *psample_group; |
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/* last reference to action, no need to lock */ |
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psample_group = rcu_dereference_protected(s->psample_group, 1); |
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RCU_INIT_POINTER(s->psample_group, NULL); |
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if (psample_group) |
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psample_group_put(psample_group); |
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} |
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static bool tcf_sample_dev_ok_push(struct net_device *dev) |
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{ |
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switch (dev->type) { |
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case ARPHRD_TUNNEL: |
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case ARPHRD_TUNNEL6: |
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case ARPHRD_SIT: |
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case ARPHRD_IPGRE: |
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case ARPHRD_IP6GRE: |
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case ARPHRD_VOID: |
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case ARPHRD_NONE: |
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return false; |
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default: |
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return true; |
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} |
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} |
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static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a, |
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struct tcf_result *res) |
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{ |
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struct tcf_sample *s = to_sample(a); |
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struct psample_group *psample_group; |
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int retval; |
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int size; |
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int iif; |
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int oif; |
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tcf_lastuse_update(&s->tcf_tm); |
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bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb); |
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retval = READ_ONCE(s->tcf_action); |
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psample_group = rcu_dereference_bh(s->psample_group); |
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/* randomly sample packets according to rate */ |
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if (psample_group && (prandom_u32() % s->rate == 0)) { |
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if (!skb_at_tc_ingress(skb)) { |
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iif = skb->skb_iif; |
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oif = skb->dev->ifindex; |
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} else { |
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iif = skb->dev->ifindex; |
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oif = 0; |
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} |
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/* on ingress, the mac header gets popped, so push it back */ |
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if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) |
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skb_push(skb, skb->mac_len); |
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size = s->truncate ? s->trunc_size : skb->len; |
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psample_sample_packet(psample_group, skb, size, iif, oif, |
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s->rate); |
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if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev)) |
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skb_pull(skb, skb->mac_len); |
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} |
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return retval; |
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} |
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static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, |
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int bind, int ref) |
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{ |
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unsigned char *b = skb_tail_pointer(skb); |
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struct tcf_sample *s = to_sample(a); |
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struct tc_sample opt = { |
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.index = s->tcf_index, |
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.refcnt = refcount_read(&s->tcf_refcnt) - ref, |
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.bindcnt = atomic_read(&s->tcf_bindcnt) - bind, |
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}; |
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struct tcf_t t; |
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spin_lock_bh(&s->tcf_lock); |
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opt.action = s->tcf_action; |
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if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) |
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goto nla_put_failure; |
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tcf_tm_dump(&t, &s->tcf_tm); |
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if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD)) |
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goto nla_put_failure; |
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if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate)) |
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goto nla_put_failure; |
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if (s->truncate) |
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if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size)) |
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goto nla_put_failure; |
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if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) |
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goto nla_put_failure; |
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spin_unlock_bh(&s->tcf_lock); |
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return skb->len; |
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nla_put_failure: |
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spin_unlock_bh(&s->tcf_lock); |
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nlmsg_trim(skb, b); |
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return -1; |
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} |
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static int tcf_sample_walker(struct net *net, struct sk_buff *skb, |
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struct netlink_callback *cb, int type, |
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const struct tc_action_ops *ops, |
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struct netlink_ext_ack *extack) |
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{ |
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struct tc_action_net *tn = net_generic(net, sample_net_id); |
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return tcf_generic_walker(tn, skb, cb, type, ops, extack); |
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} |
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static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index) |
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{ |
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struct tc_action_net *tn = net_generic(net, sample_net_id); |
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return tcf_idr_search(tn, a, index); |
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} |
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static void tcf_psample_group_put(void *priv) |
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{ |
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struct psample_group *group = priv; |
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psample_group_put(group); |
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} |
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static struct psample_group * |
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tcf_sample_get_group(const struct tc_action *a, |
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tc_action_priv_destructor *destructor) |
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{ |
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struct tcf_sample *s = to_sample(a); |
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struct psample_group *group; |
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group = rcu_dereference_protected(s->psample_group, |
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lockdep_is_held(&s->tcf_lock)); |
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if (group) { |
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psample_group_take(group); |
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*destructor = tcf_psample_group_put; |
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} |
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return group; |
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} |
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static struct tc_action_ops act_sample_ops = { |
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.kind = "sample", |
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.id = TCA_ID_SAMPLE, |
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.owner = THIS_MODULE, |
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.act = tcf_sample_act, |
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.dump = tcf_sample_dump, |
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.init = tcf_sample_init, |
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.cleanup = tcf_sample_cleanup, |
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.walk = tcf_sample_walker, |
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.lookup = tcf_sample_search, |
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.get_psample_group = tcf_sample_get_group, |
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.size = sizeof(struct tcf_sample), |
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}; |
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static __net_init int sample_init_net(struct net *net) |
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{ |
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struct tc_action_net *tn = net_generic(net, sample_net_id); |
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return tc_action_net_init(net, tn, &act_sample_ops); |
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} |
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static void __net_exit sample_exit_net(struct list_head *net_list) |
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{ |
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tc_action_net_exit(net_list, sample_net_id); |
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} |
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static struct pernet_operations sample_net_ops = { |
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.init = sample_init_net, |
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.exit_batch = sample_exit_net, |
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.id = &sample_net_id, |
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.size = sizeof(struct tc_action_net), |
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}; |
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static int __init sample_init_module(void) |
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{ |
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return tcf_register_action(&act_sample_ops, &sample_net_ops); |
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} |
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static void __exit sample_cleanup_module(void) |
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{ |
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tcf_unregister_action(&act_sample_ops, &sample_net_ops); |
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} |
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module_init(sample_init_module); |
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module_exit(sample_cleanup_module); |
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MODULE_AUTHOR("Yotam Gigi <[email protected]>"); |
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MODULE_DESCRIPTION("Packet sampling action"); |
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MODULE_LICENSE("GPL v2");
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