~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/core/lwt_bpf.c

Version: ~ [ linux-5.3-rc5 ] ~ [ linux-5.2.9 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.67 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.139 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.189 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.189 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.72 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
  2  *
  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.
  6  *
  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.
 11  */
 12 
 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>
 19 
 20 struct bpf_lwt_prog {
 21         struct bpf_prog *prog;
 22         char *name;
 23 };
 24 
 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;
 30 };
 31 
 32 #define MAX_PROG_NAME 256
 33 
 34 static inline struct bpf_lwt *bpf_lwt_lwtunnel(struct lwtunnel_state *lwt)
 35 {
 36         return (struct bpf_lwt *)lwt->data;
 37 }
 38 
 39 #define NO_REDIRECT false
 40 #define CAN_REDIRECT true
 41 
 42 static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
 43                        struct dst_entry *dst, bool can_redirect)
 44 {
 45         int ret;
 46 
 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.
 51          */
 52         preempt_disable();
 53         rcu_read_lock();
 54         bpf_compute_data_end(skb);
 55         ret = bpf_prog_run_save_cb(lwt->prog, skb);
 56         rcu_read_unlock();
 57 
 58         switch (ret) {
 59         case BPF_OK:
 60                 break;
 61 
 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;
 71                 }
 72                 break;
 73 
 74         case BPF_DROP:
 75                 kfree_skb(skb);
 76                 ret = -EPERM;
 77                 break;
 78 
 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;
 84         }
 85 
 86         preempt_enable();
 87 
 88         return ret;
 89 }
 90 
 91 static int bpf_input(struct sk_buff *skb)
 92 {
 93         struct dst_entry *dst = skb_dst(skb);
 94         struct bpf_lwt *bpf;
 95         int ret;
 96 
 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;
102         }
103 
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;
109         }
110 
111         return dst->lwtstate->orig_input(skb);
112 }
113 
114 static int bpf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
115 {
116         struct dst_entry *dst = skb_dst(skb);
117         struct bpf_lwt *bpf;
118         int ret;
119 
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;
125         }
126 
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;
132         }
133 
134         return dst->lwtstate->orig_output(net, sk, skb);
135 }
136 
137 static int xmit_check_hhlen(struct sk_buff *skb)
138 {
139         int hh_len = skb_dst(skb)->dev->hard_header_len;
140 
141         if (skb_headroom(skb) < hh_len) {
142                 int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
143 
144                 if (pskb_expand_head(skb, nhead, 0, GFP_ATOMIC))
145                         return -ENOMEM;
146         }
147 
148         return 0;
149 }
150 
151 static int bpf_xmit(struct sk_buff *skb)
152 {
153         struct dst_entry *dst = skb_dst(skb);
154         struct bpf_lwt *bpf;
155 
156         bpf = bpf_lwt_lwtunnel(dst->lwtstate);
157         if (bpf->xmit.prog) {
158                 int ret;
159 
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.
165                          */
166                         ret = xmit_check_hhlen(skb);
167                         if (unlikely(ret))
168                                 return ret;
169 
170                         return LWTUNNEL_XMIT_CONTINUE;
171                 case BPF_REDIRECT:
172                         return LWTUNNEL_XMIT_DONE;
173                 default:
174                         return ret;
175                 }
176         }
177 
178         return LWTUNNEL_XMIT_CONTINUE;
179 }
180 
181 static void bpf_lwt_prog_destroy(struct bpf_lwt_prog *prog)
182 {
183         if (prog->prog)
184                 bpf_prog_put(prog->prog);
185 
186         kfree(prog->name);
187 }
188 
189 static void bpf_destroy_state(struct lwtunnel_state *lwt)
190 {
191         struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
192 
193         bpf_lwt_prog_destroy(&bpf->in);
194         bpf_lwt_prog_destroy(&bpf->out);
195         bpf_lwt_prog_destroy(&bpf->xmit);
196 }
197 
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 },
202 };
203 
204 static int bpf_parse_prog(struct nlattr *attr, struct bpf_lwt_prog *prog,
205                           enum bpf_prog_type type)
206 {
207         struct nlattr *tb[LWT_BPF_PROG_MAX + 1];
208         struct bpf_prog *p;
209         int ret;
210         u32 fd;
211 
212         ret = nla_parse_nested(tb, LWT_BPF_PROG_MAX, attr, bpf_prog_policy);
213         if (ret < 0)
214                 return ret;
215 
216         if (!tb[LWT_BPF_PROG_FD] || !tb[LWT_BPF_PROG_NAME])
217                 return -EINVAL;
218 
219         prog->name = nla_memdup(tb[LWT_BPF_PROG_NAME], GFP_KERNEL);
220         if (!prog->name)
221                 return -ENOMEM;
222 
223         fd = nla_get_u32(tb[LWT_BPF_PROG_FD]);
224         p = bpf_prog_get_type(fd, type);
225         if (IS_ERR(p))
226                 return PTR_ERR(p);
227 
228         prog->prog = p;
229 
230         return 0;
231 }
232 
233 static const struct nla_policy bpf_nl_policy[LWT_BPF_MAX + 1] = {
234         [LWT_BPF_IN]            = { .type = NLA_NESTED, },
235         [LWT_BPF_OUT]           = { .type = NLA_NESTED, },
236         [LWT_BPF_XMIT]          = { .type = NLA_NESTED, },
237         [LWT_BPF_XMIT_HEADROOM] = { .type = NLA_U32 },
238 };
239 
240 static int bpf_build_state(struct net_device *dev, struct nlattr *nla,
241                            unsigned int family, const void *cfg,
242                            struct lwtunnel_state **ts)
243 {
244         struct nlattr *tb[LWT_BPF_MAX + 1];
245         struct lwtunnel_state *newts;
246         struct bpf_lwt *bpf;
247         int ret;
248 
249         if (family != AF_INET && family != AF_INET6)
250                 return -EAFNOSUPPORT;
251 
252         ret = nla_parse_nested(tb, LWT_BPF_MAX, nla, bpf_nl_policy);
253         if (ret < 0)
254                 return ret;
255 
256         if (!tb[LWT_BPF_IN] && !tb[LWT_BPF_OUT] && !tb[LWT_BPF_XMIT])
257                 return -EINVAL;
258 
259         newts = lwtunnel_state_alloc(sizeof(*bpf));
260         if (!newts)
261                 return -ENOMEM;
262 
263         newts->type = LWTUNNEL_ENCAP_BPF;
264         bpf = bpf_lwt_lwtunnel(newts);
265 
266         if (tb[LWT_BPF_IN]) {
267                 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
268                 ret = bpf_parse_prog(tb[LWT_BPF_IN], &bpf->in,
269                                      BPF_PROG_TYPE_LWT_IN);
270                 if (ret  < 0)
271                         goto errout;
272         }
273 
274         if (tb[LWT_BPF_OUT]) {
275                 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
276                 ret = bpf_parse_prog(tb[LWT_BPF_OUT], &bpf->out,
277                                      BPF_PROG_TYPE_LWT_OUT);
278                 if (ret < 0)
279                         goto errout;
280         }
281 
282         if (tb[LWT_BPF_XMIT]) {
283                 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
284                 ret = bpf_parse_prog(tb[LWT_BPF_XMIT], &bpf->xmit,
285                                      BPF_PROG_TYPE_LWT_XMIT);
286                 if (ret < 0)
287                         goto errout;
288         }
289 
290         if (tb[LWT_BPF_XMIT_HEADROOM]) {
291                 u32 headroom = nla_get_u32(tb[LWT_BPF_XMIT_HEADROOM]);
292 
293                 if (headroom > LWT_BPF_MAX_HEADROOM) {
294                         ret = -ERANGE;
295                         goto errout;
296                 }
297 
298                 newts->headroom = headroom;
299         }
300 
301         bpf->family = family;
302         *ts = newts;
303 
304         return 0;
305 
306 errout:
307         bpf_destroy_state(newts);
308         kfree(newts);
309         return ret;
310 }
311 
312 static int bpf_fill_lwt_prog(struct sk_buff *skb, int attr,
313                              struct bpf_lwt_prog *prog)
314 {
315         struct nlattr *nest;
316 
317         if (!prog->prog)
318                 return 0;
319 
320         nest = nla_nest_start(skb, attr);
321         if (!nest)
322                 return -EMSGSIZE;
323 
324         if (prog->name &&
325             nla_put_string(skb, LWT_BPF_PROG_NAME, prog->name))
326                 return -EMSGSIZE;
327 
328         return nla_nest_end(skb, nest);
329 }
330 
331 static int bpf_fill_encap_info(struct sk_buff *skb, struct lwtunnel_state *lwt)
332 {
333         struct bpf_lwt *bpf = bpf_lwt_lwtunnel(lwt);
334 
335         if (bpf_fill_lwt_prog(skb, LWT_BPF_IN, &bpf->in) < 0 ||
336             bpf_fill_lwt_prog(skb, LWT_BPF_OUT, &bpf->out) < 0 ||
337             bpf_fill_lwt_prog(skb, LWT_BPF_XMIT, &bpf->xmit) < 0)
338                 return -EMSGSIZE;
339 
340         return 0;
341 }
342 
343 static int bpf_encap_nlsize(struct lwtunnel_state *lwtstate)
344 {
345         int nest_len = nla_total_size(sizeof(struct nlattr)) +
346                        nla_total_size(MAX_PROG_NAME) + /* LWT_BPF_PROG_NAME */
347                        0;
348 
349         return nest_len + /* LWT_BPF_IN */
350                nest_len + /* LWT_BPF_OUT */
351                nest_len + /* LWT_BPF_XMIT */
352                0;
353 }
354 
355 int bpf_lwt_prog_cmp(struct bpf_lwt_prog *a, struct bpf_lwt_prog *b)
356 {
357         /* FIXME:
358          * The LWT state is currently rebuilt for delete requests which
359          * results in a new bpf_prog instance. Comparing names for now.
360          */
361         if (!a->name && !b->name)
362                 return 0;
363 
364         if (!a->name || !b->name)
365                 return 1;
366 
367         return strcmp(a->name, b->name);
368 }
369 
370 static int bpf_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
371 {
372         struct bpf_lwt *a_bpf = bpf_lwt_lwtunnel(a);
373         struct bpf_lwt *b_bpf = bpf_lwt_lwtunnel(b);
374 
375         return bpf_lwt_prog_cmp(&a_bpf->in, &b_bpf->in) ||
376                bpf_lwt_prog_cmp(&a_bpf->out, &b_bpf->out) ||
377                bpf_lwt_prog_cmp(&a_bpf->xmit, &b_bpf->xmit);
378 }
379 
380 static const struct lwtunnel_encap_ops bpf_encap_ops = {
381         .build_state    = bpf_build_state,
382         .destroy_state  = bpf_destroy_state,
383         .input          = bpf_input,
384         .output         = bpf_output,
385         .xmit           = bpf_xmit,
386         .fill_encap     = bpf_fill_encap_info,
387         .get_encap_size = bpf_encap_nlsize,
388         .cmp_encap      = bpf_encap_cmp,
389         .owner          = THIS_MODULE,
390 };
391 
392 static int __init bpf_lwt_init(void)
393 {
394         return lwtunnel_encap_add_ops(&bpf_encap_ops, LWTUNNEL_ENCAP_BPF);
395 }
396 
397 subsys_initcall(bpf_lwt_init)
398 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp