i2c: designware-master: use core to detect 'no zero length' quirk
[linux/fpc-iii.git] / net / core / lwt_bpf.c
blobe7e626fb87bb34f89014cb16e58aaaf132c65417
1 /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
7 * This program is distributed in the hope that it will be useful, but
8 * WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * General Public License for more details.
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/types.h>
17 #include <linux/bpf.h>
18 #include <net/lwtunnel.h>
20 struct bpf_lwt_prog {
21 struct bpf_prog *prog;
22 char *name;
25 struct bpf_lwt {
26 struct bpf_lwt_prog in;
27 struct bpf_lwt_prog out;
28 struct bpf_lwt_prog xmit;
29 int family;
32 #define MAX_PROG_NAME 256
34 static inline struct bpf_lwt *bpf_lwt_lwtunnel(struct lwtunnel_state *lwt)
36 return (struct bpf_lwt *)lwt->data;
39 #define NO_REDIRECT false
40 #define CAN_REDIRECT true
42 static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
43 struct dst_entry *dst, bool can_redirect)
45 int ret;
47 /* Preempt disable is needed to protect per-cpu redirect_info between
48 * BPF prog and skb_do_redirect(). The call_rcu in bpf_prog_put() and
49 * access to maps strictly require a rcu_read_lock() for protection,
50 * mixing with BH RCU lock doesn't work.
52 preempt_disable();
53 rcu_read_lock();
54 bpf_compute_data_pointers(skb);
55 ret = bpf_prog_run_save_cb(lwt->prog, skb);
56 rcu_read_unlock();
58 switch (ret) {
59 case BPF_OK:
60 break;
62 case BPF_REDIRECT:
63 if (unlikely(!can_redirect)) {
64 pr_warn_once("Illegal redirect return code in prog %s\n",
65 lwt->name ? : "<unknown>");
66 ret = BPF_OK;
67 } else {
68 ret = skb_do_redirect(skb);
69 if (ret == 0)
70 ret = BPF_REDIRECT;
72 break;
74 case BPF_DROP:
75 kfree_skb(skb);
76 ret = -EPERM;
77 break;
79 default:
80 pr_warn_once("bpf-lwt: Illegal return value %u, expect packet loss\n", ret);
81 kfree_skb(skb);
82 ret = -EINVAL;
83 break;
86 preempt_enable();
88 return ret;
91 static int bpf_input(struct sk_buff *skb)
93 struct dst_entry *dst = skb_dst(skb);
94 struct bpf_lwt *bpf;
95 int ret;
97 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
98 if (bpf->in.prog) {
99 ret = run_lwt_bpf(skb, &bpf->in, dst, NO_REDIRECT);
100 if (ret < 0)
101 return ret;
104 if (unlikely(!dst->lwtstate->orig_input)) {
105 pr_warn_once("orig_input not set on dst for prog %s\n",
106 bpf->out.name);
107 kfree_skb(skb);
108 return -EINVAL;
111 return dst->lwtstate->orig_input(skb);
114 static int bpf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
116 struct dst_entry *dst = skb_dst(skb);
117 struct bpf_lwt *bpf;
118 int ret;
120 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
121 if (bpf->out.prog) {
122 ret = run_lwt_bpf(skb, &bpf->out, dst, NO_REDIRECT);
123 if (ret < 0)
124 return ret;
127 if (unlikely(!dst->lwtstate->orig_output)) {
128 pr_warn_once("orig_output not set on dst for prog %s\n",
129 bpf->out.name);
130 kfree_skb(skb);
131 return -EINVAL;
134 return dst->lwtstate->orig_output(net, sk, skb);
137 static int xmit_check_hhlen(struct sk_buff *skb)
139 int hh_len = skb_dst(skb)->dev->hard_header_len;
141 if (skb_headroom(skb) < hh_len) {
142 int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
144 if (pskb_expand_head(skb, nhead, 0, GFP_ATOMIC))
145 return -ENOMEM;
148 return 0;
151 static int bpf_xmit(struct sk_buff *skb)
153 struct dst_entry *dst = skb_dst(skb);
154 struct bpf_lwt *bpf;
156 bpf = bpf_lwt_lwtunnel(dst->lwtstate);
157 if (bpf->xmit.prog) {
158 int ret;
160 ret = run_lwt_bpf(skb, &bpf->xmit, dst, CAN_REDIRECT);
161 switch (ret) {
162 case BPF_OK:
163 /* If the header was expanded, headroom might be too
164 * small for L2 header to come, expand as needed.
166 ret = xmit_check_hhlen(skb);
167 if (unlikely(ret))
168 return ret;
170 return LWTUNNEL_XMIT_CONTINUE;
171 case BPF_REDIRECT:
172 return LWTUNNEL_XMIT_DONE;
173 default:
174 return ret;
178 return LWTUNNEL_XMIT_CONTINUE;
181 static void bpf_lwt_prog_destroy(struct bpf_lwt_prog *prog)
183 if (prog->prog)
184 bpf_prog_put(prog->prog);
186 kfree(prog->name);
189 static void bpf_destroy_state(struct lwtunnel_state *lwt)
191 struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
193 bpf_lwt_prog_destroy(&bpf->in);
194 bpf_lwt_prog_destroy(&bpf->out);
195 bpf_lwt_prog_destroy(&bpf->xmit);
198 static const struct nla_policy bpf_prog_policy[LWT_BPF_PROG_MAX + 1] = {
199 [LWT_BPF_PROG_FD] = { .type = NLA_U32, },
200 [LWT_BPF_PROG_NAME] = { .type = NLA_NUL_STRING,
201 .len = MAX_PROG_NAME },
204 static int bpf_parse_prog(struct nlattr *attr, struct bpf_lwt_prog *prog,
205 enum bpf_prog_type type)
207 struct nlattr *tb[LWT_BPF_PROG_MAX + 1];
208 struct bpf_prog *p;
209 int ret;
210 u32 fd;
212 ret = nla_parse_nested(tb, LWT_BPF_PROG_MAX, attr, bpf_prog_policy,
213 NULL);
214 if (ret < 0)
215 return ret;
217 if (!tb[LWT_BPF_PROG_FD] || !tb[LWT_BPF_PROG_NAME])
218 return -EINVAL;
220 prog->name = nla_memdup(tb[LWT_BPF_PROG_NAME], GFP_KERNEL);
221 if (!prog->name)
222 return -ENOMEM;
224 fd = nla_get_u32(tb[LWT_BPF_PROG_FD]);
225 p = bpf_prog_get_type(fd, type);
226 if (IS_ERR(p))
227 return PTR_ERR(p);
229 prog->prog = p;
231 return 0;
234 static const struct nla_policy bpf_nl_policy[LWT_BPF_MAX + 1] = {
235 [LWT_BPF_IN] = { .type = NLA_NESTED, },
236 [LWT_BPF_OUT] = { .type = NLA_NESTED, },
237 [LWT_BPF_XMIT] = { .type = NLA_NESTED, },
238 [LWT_BPF_XMIT_HEADROOM] = { .type = NLA_U32 },
241 static int bpf_build_state(struct nlattr *nla,
242 unsigned int family, const void *cfg,
243 struct lwtunnel_state **ts,
244 struct netlink_ext_ack *extack)
246 struct nlattr *tb[LWT_BPF_MAX + 1];
247 struct lwtunnel_state *newts;
248 struct bpf_lwt *bpf;
249 int ret;
251 if (family != AF_INET && family != AF_INET6)
252 return -EAFNOSUPPORT;
254 ret = nla_parse_nested(tb, LWT_BPF_MAX, nla, bpf_nl_policy, extack);
255 if (ret < 0)
256 return ret;
258 if (!tb[LWT_BPF_IN] && !tb[LWT_BPF_OUT] && !tb[LWT_BPF_XMIT])
259 return -EINVAL;
261 newts = lwtunnel_state_alloc(sizeof(*bpf));
262 if (!newts)
263 return -ENOMEM;
265 newts->type = LWTUNNEL_ENCAP_BPF;
266 bpf = bpf_lwt_lwtunnel(newts);
268 if (tb[LWT_BPF_IN]) {
269 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
270 ret = bpf_parse_prog(tb[LWT_BPF_IN], &bpf->in,
271 BPF_PROG_TYPE_LWT_IN);
272 if (ret < 0)
273 goto errout;
276 if (tb[LWT_BPF_OUT]) {
277 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
278 ret = bpf_parse_prog(tb[LWT_BPF_OUT], &bpf->out,
279 BPF_PROG_TYPE_LWT_OUT);
280 if (ret < 0)
281 goto errout;
284 if (tb[LWT_BPF_XMIT]) {
285 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
286 ret = bpf_parse_prog(tb[LWT_BPF_XMIT], &bpf->xmit,
287 BPF_PROG_TYPE_LWT_XMIT);
288 if (ret < 0)
289 goto errout;
292 if (tb[LWT_BPF_XMIT_HEADROOM]) {
293 u32 headroom = nla_get_u32(tb[LWT_BPF_XMIT_HEADROOM]);
295 if (headroom > LWT_BPF_MAX_HEADROOM) {
296 ret = -ERANGE;
297 goto errout;
300 newts->headroom = headroom;
303 bpf->family = family;
304 *ts = newts;
306 return 0;
308 errout:
309 bpf_destroy_state(newts);
310 kfree(newts);
311 return ret;
314 static int bpf_fill_lwt_prog(struct sk_buff *skb, int attr,
315 struct bpf_lwt_prog *prog)
317 struct nlattr *nest;
319 if (!prog->prog)
320 return 0;
322 nest = nla_nest_start(skb, attr);
323 if (!nest)
324 return -EMSGSIZE;
326 if (prog->name &&
327 nla_put_string(skb, LWT_BPF_PROG_NAME, prog->name))
328 return -EMSGSIZE;
330 return nla_nest_end(skb, nest);
333 static int bpf_fill_encap_info(struct sk_buff *skb, struct lwtunnel_state *lwt)
335 struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
337 if (bpf_fill_lwt_prog(skb, LWT_BPF_IN, &bpf->in) < 0 ||
338 bpf_fill_lwt_prog(skb, LWT_BPF_OUT, &bpf->out) < 0 ||
339 bpf_fill_lwt_prog(skb, LWT_BPF_XMIT, &bpf->xmit) < 0)
340 return -EMSGSIZE;
342 return 0;
345 static int bpf_encap_nlsize(struct lwtunnel_state *lwtstate)
347 int nest_len = nla_total_size(sizeof(struct nlattr)) +
348 nla_total_size(MAX_PROG_NAME) + /* LWT_BPF_PROG_NAME */
351 return nest_len + /* LWT_BPF_IN */
352 nest_len + /* LWT_BPF_OUT */
353 nest_len + /* LWT_BPF_XMIT */
357 static int bpf_lwt_prog_cmp(struct bpf_lwt_prog *a, struct bpf_lwt_prog *b)
359 /* FIXME:
360 * The LWT state is currently rebuilt for delete requests which
361 * results in a new bpf_prog instance. Comparing names for now.
363 if (!a->name && !b->name)
364 return 0;
366 if (!a->name || !b->name)
367 return 1;
369 return strcmp(a->name, b->name);
372 static int bpf_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
374 struct bpf_lwt *a_bpf = bpf_lwt_lwtunnel(a);
375 struct bpf_lwt *b_bpf = bpf_lwt_lwtunnel(b);
377 return bpf_lwt_prog_cmp(&a_bpf->in, &b_bpf->in) ||
378 bpf_lwt_prog_cmp(&a_bpf->out, &b_bpf->out) ||
379 bpf_lwt_prog_cmp(&a_bpf->xmit, &b_bpf->xmit);
382 static const struct lwtunnel_encap_ops bpf_encap_ops = {
383 .build_state = bpf_build_state,
384 .destroy_state = bpf_destroy_state,
385 .input = bpf_input,
386 .output = bpf_output,
387 .xmit = bpf_xmit,
388 .fill_encap = bpf_fill_encap_info,
389 .get_encap_size = bpf_encap_nlsize,
390 .cmp_encap = bpf_encap_cmp,
391 .owner = THIS_MODULE,
394 static int __init bpf_lwt_init(void)
396 return lwtunnel_encap_add_ops(&bpf_encap_ops, LWTUNNEL_ENCAP_BPF);
399 subsys_initcall(bpf_lwt_init)