]>
Commit | Line | Data |
---|---|---|
d23b8ad8 JP |
1 | /* |
2 | * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/skbuff.h> | |
14 | #include <linux/rtnetlink.h> | |
15 | #include <linux/filter.h> | |
16 | #include <net/netlink.h> | |
17 | #include <net/pkt_sched.h> | |
18 | ||
19 | #include <linux/tc_act/tc_bpf.h> | |
20 | #include <net/tc_act/tc_bpf.h> | |
21 | ||
22 | #define BPF_TAB_MASK 15 | |
23 | ||
24 | static int tcf_bpf(struct sk_buff *skb, const struct tc_action *a, | |
25 | struct tcf_result *res) | |
26 | { | |
27 | struct tcf_bpf *b = a->priv; | |
28 | int action; | |
29 | int filter_res; | |
30 | ||
31 | spin_lock(&b->tcf_lock); | |
32 | b->tcf_tm.lastuse = jiffies; | |
33 | bstats_update(&b->tcf_bstats, skb); | |
34 | action = b->tcf_action; | |
35 | ||
36 | filter_res = BPF_PROG_RUN(b->filter, skb); | |
37 | if (filter_res == 0) { | |
38 | /* Return code 0 from the BPF program | |
39 | * is being interpreted as a drop here. | |
40 | */ | |
41 | action = TC_ACT_SHOT; | |
42 | b->tcf_qstats.drops++; | |
43 | } | |
44 | ||
45 | spin_unlock(&b->tcf_lock); | |
46 | return action; | |
47 | } | |
48 | ||
49 | static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *a, | |
50 | int bind, int ref) | |
51 | { | |
52 | unsigned char *tp = skb_tail_pointer(skb); | |
53 | struct tcf_bpf *b = a->priv; | |
54 | struct tc_act_bpf opt = { | |
55 | .index = b->tcf_index, | |
56 | .refcnt = b->tcf_refcnt - ref, | |
57 | .bindcnt = b->tcf_bindcnt - bind, | |
58 | .action = b->tcf_action, | |
59 | }; | |
60 | struct tcf_t t; | |
61 | struct nlattr *nla; | |
62 | ||
63 | if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) | |
64 | goto nla_put_failure; | |
65 | ||
66 | if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, b->bpf_num_ops)) | |
67 | goto nla_put_failure; | |
68 | ||
69 | nla = nla_reserve(skb, TCA_ACT_BPF_OPS, b->bpf_num_ops * | |
70 | sizeof(struct sock_filter)); | |
71 | if (!nla) | |
72 | goto nla_put_failure; | |
73 | ||
74 | memcpy(nla_data(nla), b->bpf_ops, nla_len(nla)); | |
75 | ||
76 | t.install = jiffies_to_clock_t(jiffies - b->tcf_tm.install); | |
77 | t.lastuse = jiffies_to_clock_t(jiffies - b->tcf_tm.lastuse); | |
78 | t.expires = jiffies_to_clock_t(b->tcf_tm.expires); | |
79 | if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(t), &t)) | |
80 | goto nla_put_failure; | |
81 | return skb->len; | |
82 | ||
83 | nla_put_failure: | |
84 | nlmsg_trim(skb, tp); | |
85 | return -1; | |
86 | } | |
87 | ||
88 | static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { | |
89 | [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, | |
90 | [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, | |
91 | [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, | |
92 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
93 | }; | |
94 | ||
95 | static int tcf_bpf_init(struct net *net, struct nlattr *nla, | |
96 | struct nlattr *est, struct tc_action *a, | |
97 | int ovr, int bind) | |
98 | { | |
99 | struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; | |
100 | struct tc_act_bpf *parm; | |
101 | struct tcf_bpf *b; | |
102 | u16 bpf_size, bpf_num_ops; | |
103 | struct sock_filter *bpf_ops; | |
104 | struct sock_fprog_kern tmp; | |
105 | struct bpf_prog *fp; | |
106 | int ret; | |
107 | ||
108 | if (!nla) | |
109 | return -EINVAL; | |
110 | ||
111 | ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy); | |
112 | if (ret < 0) | |
113 | return ret; | |
114 | ||
115 | if (!tb[TCA_ACT_BPF_PARMS] || | |
116 | !tb[TCA_ACT_BPF_OPS_LEN] || !tb[TCA_ACT_BPF_OPS]) | |
117 | return -EINVAL; | |
118 | parm = nla_data(tb[TCA_ACT_BPF_PARMS]); | |
119 | ||
120 | bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); | |
121 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) | |
122 | return -EINVAL; | |
123 | ||
124 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); | |
125 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); | |
126 | if (!bpf_ops) | |
127 | return -ENOMEM; | |
128 | ||
129 | memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); | |
130 | ||
131 | tmp.len = bpf_num_ops; | |
132 | tmp.filter = bpf_ops; | |
133 | ||
134 | ret = bpf_prog_create(&fp, &tmp); | |
135 | if (ret) | |
136 | goto free_bpf_ops; | |
137 | ||
138 | if (!tcf_hash_check(parm->index, a, bind)) { | |
139 | ret = tcf_hash_create(parm->index, est, a, sizeof(*b), bind); | |
140 | if (ret) | |
141 | goto destroy_fp; | |
142 | ||
143 | ret = ACT_P_CREATED; | |
144 | } else { | |
145 | if (bind) | |
146 | goto destroy_fp; | |
147 | tcf_hash_release(a, bind); | |
148 | if (!ovr) { | |
149 | ret = -EEXIST; | |
150 | goto destroy_fp; | |
151 | } | |
152 | } | |
153 | ||
154 | b = to_bpf(a); | |
155 | spin_lock_bh(&b->tcf_lock); | |
156 | b->tcf_action = parm->action; | |
157 | b->bpf_num_ops = bpf_num_ops; | |
158 | b->bpf_ops = bpf_ops; | |
159 | b->filter = fp; | |
160 | spin_unlock_bh(&b->tcf_lock); | |
161 | ||
162 | if (ret == ACT_P_CREATED) | |
163 | tcf_hash_insert(a); | |
164 | return ret; | |
165 | ||
166 | destroy_fp: | |
167 | bpf_prog_destroy(fp); | |
168 | free_bpf_ops: | |
169 | kfree(bpf_ops); | |
170 | return ret; | |
171 | } | |
172 | ||
173 | static void tcf_bpf_cleanup(struct tc_action *a, int bind) | |
174 | { | |
175 | struct tcf_bpf *b = a->priv; | |
176 | ||
177 | bpf_prog_destroy(b->filter); | |
178 | } | |
179 | ||
180 | static struct tc_action_ops act_bpf_ops = { | |
181 | .kind = "bpf", | |
182 | .type = TCA_ACT_BPF, | |
183 | .owner = THIS_MODULE, | |
184 | .act = tcf_bpf, | |
185 | .dump = tcf_bpf_dump, | |
186 | .cleanup = tcf_bpf_cleanup, | |
187 | .init = tcf_bpf_init, | |
188 | }; | |
189 | ||
190 | static int __init bpf_init_module(void) | |
191 | { | |
192 | return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK); | |
193 | } | |
194 | ||
195 | static void __exit bpf_cleanup_module(void) | |
196 | { | |
197 | tcf_unregister_action(&act_bpf_ops); | |
198 | } | |
199 | ||
200 | module_init(bpf_init_module); | |
201 | module_exit(bpf_cleanup_module); | |
202 | ||
203 | MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); | |
204 | MODULE_DESCRIPTION("TC BPF based action"); | |
205 | MODULE_LICENSE("GPL v2"); |