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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; | |
ced585c8 | 28 | int action, filter_res; |
d23b8ad8 JP |
29 | |
30 | spin_lock(&b->tcf_lock); | |
ced585c8 | 31 | |
d23b8ad8 JP |
32 | b->tcf_tm.lastuse = jiffies; |
33 | bstats_update(&b->tcf_bstats, skb); | |
d23b8ad8 JP |
34 | |
35 | filter_res = BPF_PROG_RUN(b->filter, skb); | |
ced585c8 DB |
36 | |
37 | /* A BPF program may overwrite the default action opcode. | |
38 | * Similarly as in cls_bpf, if filter_res == -1 we use the | |
39 | * default action specified from tc. | |
40 | * | |
41 | * In case a different well-known TC_ACT opcode has been | |
42 | * returned, it will overwrite the default one. | |
43 | * | |
44 | * For everything else that is unkown, TC_ACT_UNSPEC is | |
45 | * returned. | |
46 | */ | |
47 | switch (filter_res) { | |
48 | case TC_ACT_PIPE: | |
49 | case TC_ACT_RECLASSIFY: | |
50 | case TC_ACT_OK: | |
51 | action = filter_res; | |
52 | break; | |
53 | case TC_ACT_SHOT: | |
54 | action = filter_res; | |
d23b8ad8 | 55 | b->tcf_qstats.drops++; |
ced585c8 DB |
56 | break; |
57 | case TC_ACT_UNSPEC: | |
58 | action = b->tcf_action; | |
59 | break; | |
60 | default: | |
61 | action = TC_ACT_UNSPEC; | |
62 | break; | |
d23b8ad8 JP |
63 | } |
64 | ||
65 | spin_unlock(&b->tcf_lock); | |
66 | return action; | |
67 | } | |
68 | ||
69 | static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *a, | |
70 | int bind, int ref) | |
71 | { | |
72 | unsigned char *tp = skb_tail_pointer(skb); | |
73 | struct tcf_bpf *b = a->priv; | |
74 | struct tc_act_bpf opt = { | |
75 | .index = b->tcf_index, | |
76 | .refcnt = b->tcf_refcnt - ref, | |
77 | .bindcnt = b->tcf_bindcnt - bind, | |
78 | .action = b->tcf_action, | |
79 | }; | |
80 | struct tcf_t t; | |
81 | struct nlattr *nla; | |
82 | ||
83 | if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) | |
84 | goto nla_put_failure; | |
85 | ||
86 | if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, b->bpf_num_ops)) | |
87 | goto nla_put_failure; | |
88 | ||
89 | nla = nla_reserve(skb, TCA_ACT_BPF_OPS, b->bpf_num_ops * | |
90 | sizeof(struct sock_filter)); | |
91 | if (!nla) | |
92 | goto nla_put_failure; | |
93 | ||
94 | memcpy(nla_data(nla), b->bpf_ops, nla_len(nla)); | |
95 | ||
96 | t.install = jiffies_to_clock_t(jiffies - b->tcf_tm.install); | |
97 | t.lastuse = jiffies_to_clock_t(jiffies - b->tcf_tm.lastuse); | |
98 | t.expires = jiffies_to_clock_t(b->tcf_tm.expires); | |
99 | if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(t), &t)) | |
100 | goto nla_put_failure; | |
101 | return skb->len; | |
102 | ||
103 | nla_put_failure: | |
104 | nlmsg_trim(skb, tp); | |
105 | return -1; | |
106 | } | |
107 | ||
108 | static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { | |
109 | [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, | |
110 | [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, | |
111 | [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, | |
112 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
113 | }; | |
114 | ||
115 | static int tcf_bpf_init(struct net *net, struct nlattr *nla, | |
116 | struct nlattr *est, struct tc_action *a, | |
117 | int ovr, int bind) | |
118 | { | |
119 | struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; | |
120 | struct tc_act_bpf *parm; | |
121 | struct tcf_bpf *b; | |
122 | u16 bpf_size, bpf_num_ops; | |
123 | struct sock_filter *bpf_ops; | |
124 | struct sock_fprog_kern tmp; | |
125 | struct bpf_prog *fp; | |
126 | int ret; | |
127 | ||
128 | if (!nla) | |
129 | return -EINVAL; | |
130 | ||
131 | ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy); | |
132 | if (ret < 0) | |
133 | return ret; | |
134 | ||
135 | if (!tb[TCA_ACT_BPF_PARMS] || | |
136 | !tb[TCA_ACT_BPF_OPS_LEN] || !tb[TCA_ACT_BPF_OPS]) | |
137 | return -EINVAL; | |
138 | parm = nla_data(tb[TCA_ACT_BPF_PARMS]); | |
139 | ||
140 | bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); | |
141 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) | |
142 | return -EINVAL; | |
143 | ||
144 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); | |
fd3e646c DB |
145 | if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) |
146 | return -EINVAL; | |
147 | ||
d23b8ad8 JP |
148 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); |
149 | if (!bpf_ops) | |
150 | return -ENOMEM; | |
151 | ||
152 | memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); | |
153 | ||
154 | tmp.len = bpf_num_ops; | |
155 | tmp.filter = bpf_ops; | |
156 | ||
157 | ret = bpf_prog_create(&fp, &tmp); | |
158 | if (ret) | |
159 | goto free_bpf_ops; | |
160 | ||
161 | if (!tcf_hash_check(parm->index, a, bind)) { | |
162 | ret = tcf_hash_create(parm->index, est, a, sizeof(*b), bind); | |
163 | if (ret) | |
164 | goto destroy_fp; | |
165 | ||
166 | ret = ACT_P_CREATED; | |
167 | } else { | |
168 | if (bind) | |
169 | goto destroy_fp; | |
170 | tcf_hash_release(a, bind); | |
171 | if (!ovr) { | |
172 | ret = -EEXIST; | |
173 | goto destroy_fp; | |
174 | } | |
175 | } | |
176 | ||
177 | b = to_bpf(a); | |
178 | spin_lock_bh(&b->tcf_lock); | |
179 | b->tcf_action = parm->action; | |
180 | b->bpf_num_ops = bpf_num_ops; | |
181 | b->bpf_ops = bpf_ops; | |
182 | b->filter = fp; | |
183 | spin_unlock_bh(&b->tcf_lock); | |
184 | ||
185 | if (ret == ACT_P_CREATED) | |
186 | tcf_hash_insert(a); | |
187 | return ret; | |
188 | ||
189 | destroy_fp: | |
190 | bpf_prog_destroy(fp); | |
191 | free_bpf_ops: | |
192 | kfree(bpf_ops); | |
193 | return ret; | |
194 | } | |
195 | ||
196 | static void tcf_bpf_cleanup(struct tc_action *a, int bind) | |
197 | { | |
198 | struct tcf_bpf *b = a->priv; | |
199 | ||
200 | bpf_prog_destroy(b->filter); | |
201 | } | |
202 | ||
203 | static struct tc_action_ops act_bpf_ops = { | |
204 | .kind = "bpf", | |
205 | .type = TCA_ACT_BPF, | |
206 | .owner = THIS_MODULE, | |
207 | .act = tcf_bpf, | |
208 | .dump = tcf_bpf_dump, | |
209 | .cleanup = tcf_bpf_cleanup, | |
210 | .init = tcf_bpf_init, | |
211 | }; | |
212 | ||
213 | static int __init bpf_init_module(void) | |
214 | { | |
215 | return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK); | |
216 | } | |
217 | ||
218 | static void __exit bpf_cleanup_module(void) | |
219 | { | |
220 | tcf_unregister_action(&act_bpf_ops); | |
221 | } | |
222 | ||
223 | module_init(bpf_init_module); | |
224 | module_exit(bpf_cleanup_module); | |
225 | ||
226 | MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); | |
227 | MODULE_DESCRIPTION("TC BPF based action"); | |
228 | MODULE_LICENSE("GPL v2"); |