2 * firewall3 - 3rd OpenWrt UCI firewall implementation
4 * Copyright (C) 2013 Jo-Philipp Wich <jo@mein.io>
6 * Permission to use, copy, modify, and/or distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22 #define C(f, tbl, def, fmt) \
23 { FW3_FAMILY_##f, FW3_TABLE_##tbl, FW3_FLAG_##def, fmt }
25 static const struct fw3_chain_spec default_chains
[] = {
26 C(ANY
, FILTER
, UNSPEC
, "reject"),
27 C(ANY
, FILTER
, CUSTOM_CHAINS
, "input_rule"),
28 C(ANY
, FILTER
, CUSTOM_CHAINS
, "output_rule"),
29 C(ANY
, FILTER
, CUSTOM_CHAINS
, "forwarding_rule"),
30 C(ANY
, FILTER
, SYN_FLOOD
, "syn_flood"),
32 C(V4
, NAT
, CUSTOM_CHAINS
, "prerouting_rule"),
33 C(V4
, NAT
, CUSTOM_CHAINS
, "postrouting_rule"),
38 const struct fw3_option fw3_flag_opts
[] = {
39 FW3_OPT("input", target
, defaults
, policy_input
),
40 FW3_OPT("forward", target
, defaults
, policy_forward
),
41 FW3_OPT("output", target
, defaults
, policy_output
),
43 FW3_OPT("drop_invalid", bool, defaults
, drop_invalid
),
44 FW3_OPT("tcp_reject_code", reject_code
, defaults
, tcp_reject_code
),
45 FW3_OPT("any_reject_code", reject_code
, defaults
, any_reject_code
),
47 FW3_OPT("syn_flood", bool, defaults
, syn_flood
),
48 FW3_OPT("synflood_protect", bool, defaults
, syn_flood
),
49 FW3_OPT("synflood_rate", limit
, defaults
, syn_flood_rate
),
50 FW3_OPT("synflood_burst", int, defaults
, syn_flood_rate
.burst
),
52 FW3_OPT("tcp_syncookies", bool, defaults
, tcp_syncookies
),
53 FW3_OPT("tcp_ecn", int, defaults
, tcp_ecn
),
54 FW3_OPT("tcp_window_scaling", bool, defaults
, tcp_window_scaling
),
56 FW3_OPT("accept_redirects", bool, defaults
, accept_redirects
),
57 FW3_OPT("accept_source_route", bool, defaults
, accept_source_route
),
59 FW3_OPT("auto_helper", bool, defaults
, auto_helper
),
60 FW3_OPT("custom_chains", bool, defaults
, custom_chains
),
61 FW3_OPT("disable_ipv6", bool, defaults
, disable_ipv6
),
62 FW3_OPT("flow_offloading", bool, defaults
, flow_offloading
),
63 FW3_OPT("flow_offloading_hw", bool, defaults
, flow_offloading_hw
),
65 FW3_OPT("__flags_v4", int, defaults
, flags
[0]),
66 FW3_OPT("__flags_v6", int, defaults
, flags
[1]),
73 check_policy(struct uci_element
*e
, enum fw3_flag
*pol
, const char *name
)
75 if (*pol
== FW3_FLAG_UNSPEC
)
77 warn_elem(e
, "has no %s policy specified, defaulting to DROP", name
);
80 else if (*pol
> FW3_FLAG_DROP
)
82 warn_elem(e
, "has invalid %s policy, defaulting to DROP", name
);
88 check_kmod(struct uci_element
*e
, bool *module
, const char *name
)
96 snprintf(buf
, sizeof(buf
), "/sys/module/%s/refcnt", name
);
106 warn_elem(e
, "requires not available kernel module %s, disabling", name
);
111 check_any_reject_code(struct uci_element
*e
, enum fw3_reject_code
*any_reject_code
)
113 if (*any_reject_code
== FW3_REJECT_CODE_TCP_RESET
) {
114 warn_elem(e
, "tcp-reset not valid for any_reject_code, defaulting to port-unreach");
115 *any_reject_code
= FW3_REJECT_CODE_PORT_UNREACH
;
120 get_reject_code(enum fw3_family family
, enum fw3_reject_code reject_code
)
122 switch (reject_code
) {
123 case FW3_REJECT_CODE_TCP_RESET
:
125 case FW3_REJECT_CODE_PORT_UNREACH
:
126 return "port-unreach";
127 case FW3_REJECT_CODE_ADM_PROHIBITED
:
128 return family
== FW3_FAMILY_V6
? "adm-prohibited": "admin-prohib";
135 fw3_load_defaults(struct fw3_state
*state
, struct uci_package
*p
)
137 struct uci_section
*s
;
138 struct uci_element
*e
;
139 struct fw3_defaults
*defs
= &state
->defaults
;
143 defs
->tcp_reject_code
= FW3_REJECT_CODE_TCP_RESET
;
144 defs
->any_reject_code
= FW3_REJECT_CODE_PORT_UNREACH
;
145 defs
->syn_flood_rate
.rate
= 25;
146 defs
->syn_flood_rate
.burst
= 50;
147 defs
->tcp_syncookies
= true;
148 defs
->tcp_window_scaling
= true;
149 defs
->custom_chains
= true;
150 defs
->auto_helper
= true;
152 uci_foreach_element(&p
->sections
, e
)
154 s
= uci_to_section(e
);
156 if (strcmp(s
->type
, "defaults"))
161 warn_elem(e
, "ignoring duplicate section");
165 if(!fw3_parse_options(&state
->defaults
, fw3_flag_opts
, s
))
166 warn_elem(e
, "has invalid options");
168 check_policy(e
, &defs
->policy_input
, "input");
169 check_policy(e
, &defs
->policy_output
, "output");
170 check_policy(e
, &defs
->policy_forward
, "forward");
172 check_any_reject_code(e
, &defs
->any_reject_code
);
174 check_kmod(e
, &defs
->flow_offloading
, "xt_FLOWOFFLOAD");
179 fw3_print_default_chains(struct fw3_ipt_handle
*handle
, struct fw3_state
*state
,
182 struct fw3_defaults
*defs
= &state
->defaults
;
183 const struct fw3_chain_spec
*c
;
186 ((t == FW3_FLAG_REJECT) ? FW3_FLAG_DROP : t)
188 if (handle
->family
== FW3_FAMILY_V6
&& defs
->disable_ipv6
)
191 if (handle
->table
== FW3_TABLE_FILTER
)
193 fw3_ipt_set_policy(handle
, "INPUT", policy(defs
->policy_input
));
194 fw3_ipt_set_policy(handle
, "OUTPUT", policy(defs
->policy_output
));
195 fw3_ipt_set_policy(handle
, "FORWARD", policy(defs
->policy_forward
));
198 if (defs
->custom_chains
)
199 set(defs
->flags
, handle
->family
, FW3_FLAG_CUSTOM_CHAINS
);
202 set(defs
->flags
, handle
->family
, FW3_FLAG_SYN_FLOOD
);
204 for (c
= default_chains
; c
->format
; c
++)
206 /* don't touch user chains on selective stop */
207 if (reload
&& c
->flag
== FW3_FLAG_CUSTOM_CHAINS
)
210 if (!fw3_is_family(c
, handle
->family
))
213 if (c
->table
!= handle
->table
)
217 !fw3_hasbit(defs
->flags
[handle
->family
== FW3_FAMILY_V6
], c
->flag
))
220 fw3_ipt_create_chain(handle
, c
->format
);
223 set(defs
->flags
, handle
->family
, handle
->table
);
227 fw3_print_default_head_rules(struct fw3_ipt_handle
*handle
,
228 struct fw3_state
*state
, bool reload
)
231 struct fw3_defaults
*defs
= &state
->defaults
;
232 struct fw3_device lodev
= { .set
= true };
233 struct fw3_protocol tcp
= { .protocol
= 6 };
234 struct fw3_ipt_rule
*r
;
236 const char *chains
[] = {
239 "FORWARD", "forwarding",
242 switch (handle
->table
)
244 case FW3_TABLE_FILTER
:
246 sprintf(lodev
.name
, "lo");
248 r
= fw3_ipt_rule_create(handle
, NULL
, &lodev
, NULL
, NULL
, NULL
);
249 fw3_ipt_rule_target(r
, "ACCEPT");
250 fw3_ipt_rule_append(r
, "INPUT");
252 r
= fw3_ipt_rule_create(handle
, NULL
, NULL
, &lodev
, NULL
, NULL
);
253 fw3_ipt_rule_target(r
, "ACCEPT");
254 fw3_ipt_rule_append(r
, "OUTPUT");
256 if (defs
->custom_chains
)
258 for (i
= 0; i
< ARRAY_SIZE(chains
); i
+= 2)
260 r
= fw3_ipt_rule_new(handle
);
261 fw3_ipt_rule_comment(r
, "Custom %s rule chain", chains
[i
+1]);
262 fw3_ipt_rule_target(r
, "%s_rule", chains
[i
+1]);
263 fw3_ipt_rule_append(r
, chains
[i
]);
267 if (defs
->flow_offloading
)
269 r
= fw3_ipt_rule_new(handle
);
270 fw3_ipt_rule_comment(r
, "Traffic offloading");
271 fw3_ipt_rule_extra(r
, "-m conntrack --ctstate RELATED,ESTABLISHED");
272 fw3_ipt_rule_target(r
, "FLOWOFFLOAD");
273 if (defs
->flow_offloading_hw
)
274 fw3_ipt_rule_addarg(r
, false, "--hw", NULL
);
275 fw3_ipt_rule_append(r
, "FORWARD");
278 for (i
= 0; i
< ARRAY_SIZE(chains
); i
+= 2)
280 r
= fw3_ipt_rule_new(handle
);
281 fw3_ipt_rule_extra(r
, "-m conntrack --ctstate RELATED,ESTABLISHED");
282 fw3_ipt_rule_target(r
, "ACCEPT");
283 fw3_ipt_rule_append(r
, chains
[i
]);
285 if (defs
->drop_invalid
)
287 r
= fw3_ipt_rule_new(handle
);
288 fw3_ipt_rule_extra(r
, "-m conntrack --ctstate INVALID");
289 fw3_ipt_rule_target(r
, "DROP");
290 fw3_ipt_rule_append(r
, chains
[i
]);
296 r
= fw3_ipt_rule_create(handle
, &tcp
, NULL
, NULL
, NULL
, NULL
);
297 fw3_ipt_rule_extra(r
, "--syn");
298 fw3_ipt_rule_limit(r
, &defs
->syn_flood_rate
);
299 fw3_ipt_rule_target(r
, "RETURN");
300 fw3_ipt_rule_append(r
, "syn_flood");
302 r
= fw3_ipt_rule_new(handle
);
303 fw3_ipt_rule_target(r
, "DROP");
304 fw3_ipt_rule_append(r
, "syn_flood");
306 r
= fw3_ipt_rule_create(handle
, &tcp
, NULL
, NULL
, NULL
, NULL
);
307 fw3_ipt_rule_extra(r
, "--syn");
308 fw3_ipt_rule_target(r
, "syn_flood");
309 fw3_ipt_rule_append(r
, "INPUT");
312 r
= fw3_ipt_rule_create(handle
, &tcp
, NULL
, NULL
, NULL
, NULL
);
313 fw3_ipt_rule_target(r
, "REJECT");
314 fw3_ipt_rule_addarg(r
, false, "--reject-with", get_reject_code(handle
->family
, defs
->tcp_reject_code
));
315 fw3_ipt_rule_append(r
, "reject");
317 r
= fw3_ipt_rule_new(handle
);
318 fw3_ipt_rule_target(r
, "REJECT");
319 fw3_ipt_rule_addarg(r
, false, "--reject-with", get_reject_code(handle
->family
, defs
->any_reject_code
));
320 fw3_ipt_rule_append(r
, "reject");
325 if (defs
->custom_chains
)
327 r
= fw3_ipt_rule_new(handle
);
328 fw3_ipt_rule_comment(r
, "Custom prerouting rule chain");
329 fw3_ipt_rule_target(r
, "prerouting_rule");
330 fw3_ipt_rule_append(r
, "PREROUTING");
332 r
= fw3_ipt_rule_new(handle
);
333 fw3_ipt_rule_comment(r
, "Custom postrouting rule chain");
334 fw3_ipt_rule_target(r
, "postrouting_rule");
335 fw3_ipt_rule_append(r
, "POSTROUTING");
345 fw3_print_default_tail_rules(struct fw3_ipt_handle
*handle
,
346 struct fw3_state
*state
, bool reload
)
348 struct fw3_defaults
*defs
= &state
->defaults
;
349 struct fw3_ipt_rule
*r
;
351 if (handle
->table
!= FW3_TABLE_FILTER
)
354 if (defs
->policy_input
== FW3_FLAG_REJECT
)
356 r
= fw3_ipt_rule_new(handle
);
361 fw3_ipt_rule_target(r
, "reject");
362 fw3_ipt_rule_append(r
, "INPUT");
365 if (defs
->policy_output
== FW3_FLAG_REJECT
)
367 r
= fw3_ipt_rule_new(handle
);
372 fw3_ipt_rule_target(r
, "reject");
373 fw3_ipt_rule_append(r
, "OUTPUT");
376 if (defs
->policy_forward
== FW3_FLAG_REJECT
)
378 r
= fw3_ipt_rule_new(handle
);
383 fw3_ipt_rule_target(r
, "reject");
384 fw3_ipt_rule_append(r
, "FORWARD");
389 set_default(const char *name
, int set
)
392 char path
[sizeof("/proc/sys/net/ipv4/tcp_window_scaling\0")];
394 snprintf(path
, sizeof(path
), "/proc/sys/net/ipv4/tcp_%s", name
);
396 info(" * Set tcp_%s to %s", name
, set
? "on" : "off");
398 if (!(f
= fopen(path
, "w")))
400 info(" ! Unable to write value: %s", strerror(errno
));
404 fprintf(f
, "%u\n", set
);
409 fw3_set_defaults(struct fw3_state
*state
)
411 set_default("ecn", state
->defaults
.tcp_ecn
);
412 set_default("syncookies", state
->defaults
.tcp_syncookies
);
413 set_default("window_scaling", state
->defaults
.tcp_window_scaling
);
417 fw3_flush_rules(struct fw3_ipt_handle
*handle
, struct fw3_state
*state
,
420 enum fw3_flag policy
= reload
? FW3_FLAG_DROP
: FW3_FLAG_ACCEPT
;
421 struct fw3_defaults
*defs
= &state
->defaults
;
422 const struct fw3_chain_spec
*c
;
424 if (!has(defs
->flags
, handle
->family
, handle
->table
))
427 if (handle
->table
== FW3_TABLE_FILTER
)
429 fw3_ipt_set_policy(handle
, "INPUT", policy
);
430 fw3_ipt_set_policy(handle
, "OUTPUT", policy
);
431 fw3_ipt_set_policy(handle
, "FORWARD", policy
);
434 fw3_ipt_delete_id_rules(handle
, "INPUT");
435 fw3_ipt_delete_id_rules(handle
, "OUTPUT");
436 fw3_ipt_delete_id_rules(handle
, "FORWARD");
437 fw3_ipt_delete_id_rules(handle
, "PREROUTING");
438 fw3_ipt_delete_id_rules(handle
, "POSTROUTING");
440 for (c
= default_chains
; c
->format
; c
++)
442 /* don't touch user chains on selective stop */
443 if (reload
&& c
->flag
== FW3_FLAG_CUSTOM_CHAINS
)
446 if (!fw3_is_family(c
, handle
->family
))
449 if (c
->table
!= handle
->table
)
452 if (c
->flag
&& !has(defs
->flags
, handle
->family
, c
->flag
))
455 fw3_ipt_flush_chain(handle
, c
->format
);
457 /* keep certain basic chains that do not depend on any settings to
458 avoid purging unrelated user rules pointing to them */
459 if (reload
&& !c
->flag
)
462 fw3_ipt_delete_chain(handle
, c
->format
);
465 del(defs
->flags
, handle
->family
, handle
->table
);
469 fw3_flush_all(struct fw3_ipt_handle
*handle
)
471 if (handle
->table
== FW3_TABLE_FILTER
)
473 fw3_ipt_set_policy(handle
, "INPUT", FW3_FLAG_ACCEPT
);
474 fw3_ipt_set_policy(handle
, "OUTPUT", FW3_FLAG_ACCEPT
);
475 fw3_ipt_set_policy(handle
, "FORWARD", FW3_FLAG_ACCEPT
);
478 fw3_ipt_flush(handle
);