--- /dev/null
+/*
+ * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/filter.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+
+#include <linux/tc_act/tc_bpf.h>
+#include <net/tc_act/tc_bpf.h>
+
+#define BPF_TAB_MASK 15
+
+static int tcf_bpf(struct sk_buff *skb, const struct tc_action *a,
+ struct tcf_result *res)
+{
+ struct tcf_bpf *b = a->priv;
+ int action;
+ int filter_res;
+
+ spin_lock(&b->tcf_lock);
+ b->tcf_tm.lastuse = jiffies;
+ bstats_update(&b->tcf_bstats, skb);
+ action = b->tcf_action;
+
+ filter_res = BPF_PROG_RUN(b->filter, skb);
+ if (filter_res == 0) {
+ /* Return code 0 from the BPF program
+ * is being interpreted as a drop here.
+ */
+ action = TC_ACT_SHOT;
+ b->tcf_qstats.drops++;
+ }
+
+ spin_unlock(&b->tcf_lock);
+ return action;
+}
+
+static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *a,
+ int bind, int ref)
+{
+ unsigned char *tp = skb_tail_pointer(skb);
+ struct tcf_bpf *b = a->priv;
+ struct tc_act_bpf opt = {
+ .index = b->tcf_index,
+ .refcnt = b->tcf_refcnt - ref,
+ .bindcnt = b->tcf_bindcnt - bind,
+ .action = b->tcf_action,
+ };
+ struct tcf_t t;
+ struct nlattr *nla;
+
+ if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
+ goto nla_put_failure;
+
+ if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, b->bpf_num_ops))
+ goto nla_put_failure;
+
+ nla = nla_reserve(skb, TCA_ACT_BPF_OPS, b->bpf_num_ops *
+ sizeof(struct sock_filter));
+ if (!nla)
+ goto nla_put_failure;
+
+ memcpy(nla_data(nla), b->bpf_ops, nla_len(nla));
+
+ t.install = jiffies_to_clock_t(jiffies - b->tcf_tm.install);
+ t.lastuse = jiffies_to_clock_t(jiffies - b->tcf_tm.lastuse);
+ t.expires = jiffies_to_clock_t(b->tcf_tm.expires);
+ if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(t), &t))
+ goto nla_put_failure;
+ return skb->len;
+
+nla_put_failure:
+ nlmsg_trim(skb, tp);
+ return -1;
+}
+
+static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
+ [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
+ [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 },
+ [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY,
+ .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
+};
+
+static int tcf_bpf_init(struct net *net, struct nlattr *nla,
+ struct nlattr *est, struct tc_action *a,
+ int ovr, int bind)
+{
+ struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
+ struct tc_act_bpf *parm;
+ struct tcf_bpf *b;
+ u16 bpf_size, bpf_num_ops;
+ struct sock_filter *bpf_ops;
+ struct sock_fprog_kern tmp;
+ struct bpf_prog *fp;
+ int ret;
+
+ if (!nla)
+ return -EINVAL;
+
+ ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy);
+ if (ret < 0)
+ return ret;
+
+ if (!tb[TCA_ACT_BPF_PARMS] ||
+ !tb[TCA_ACT_BPF_OPS_LEN] || !tb[TCA_ACT_BPF_OPS])
+ return -EINVAL;
+ parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
+
+ bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
+ if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
+ return -EINVAL;
+
+ bpf_size = bpf_num_ops * sizeof(*bpf_ops);
+ bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
+ if (!bpf_ops)
+ return -ENOMEM;
+
+ memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
+
+ tmp.len = bpf_num_ops;
+ tmp.filter = bpf_ops;
+
+ ret = bpf_prog_create(&fp, &tmp);
+ if (ret)
+ goto free_bpf_ops;
+
+ if (!tcf_hash_check(parm->index, a, bind)) {
+ ret = tcf_hash_create(parm->index, est, a, sizeof(*b), bind);
+ if (ret)
+ goto destroy_fp;
+
+ ret = ACT_P_CREATED;
+ } else {
+ if (bind)
+ goto destroy_fp;
+ tcf_hash_release(a, bind);
+ if (!ovr) {
+ ret = -EEXIST;
+ goto destroy_fp;
+ }
+ }
+
+ b = to_bpf(a);
+ spin_lock_bh(&b->tcf_lock);
+ b->tcf_action = parm->action;
+ b->bpf_num_ops = bpf_num_ops;
+ b->bpf_ops = bpf_ops;
+ b->filter = fp;
+ spin_unlock_bh(&b->tcf_lock);
+
+ if (ret == ACT_P_CREATED)
+ tcf_hash_insert(a);
+ return ret;
+
+destroy_fp:
+ bpf_prog_destroy(fp);
+free_bpf_ops:
+ kfree(bpf_ops);
+ return ret;
+}
+
+static void tcf_bpf_cleanup(struct tc_action *a, int bind)
+{
+ struct tcf_bpf *b = a->priv;
+
+ bpf_prog_destroy(b->filter);
+}
+
+static struct tc_action_ops act_bpf_ops = {
+ .kind = "bpf",
+ .type = TCA_ACT_BPF,
+ .owner = THIS_MODULE,
+ .act = tcf_bpf,
+ .dump = tcf_bpf_dump,
+ .cleanup = tcf_bpf_cleanup,
+ .init = tcf_bpf_init,
+};
+
+static int __init bpf_init_module(void)
+{
+ return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK);
+}
+
+static void __exit bpf_cleanup_module(void)
+{
+ tcf_unregister_action(&act_bpf_ops);
+}
+
+module_init(bpf_init_module);
+module_exit(bpf_cleanup_module);
+
+MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
+MODULE_DESCRIPTION("TC BPF based action");
+MODULE_LICENSE("GPL v2");
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