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_target(struct uci_element *e, bool *available, const char *target, const bool ipv6)
90 const bool b = fw3_has_target(ipv6, target);
93 warn_elem(e, "requires unavailable target extension %s, disabling", target);
99 check_any_reject_code(struct uci_element *e, enum fw3_reject_code *any_reject_code)
101 if (*any_reject_code == FW3_REJECT_CODE_TCP_RESET) {
102 warn_elem(e, "tcp-reset not valid for any_reject_code, defaulting to port-unreach");
103 *any_reject_code = FW3_REJECT_CODE_PORT_UNREACH;
108 get_reject_code(enum fw3_family family, enum fw3_reject_code reject_code)
110 switch (reject_code) {
111 case FW3_REJECT_CODE_TCP_RESET:
113 case FW3_REJECT_CODE_PORT_UNREACH:
114 return "port-unreach";
115 case FW3_REJECT_CODE_ADM_PROHIBITED:
116 return family == FW3_FAMILY_V6 ? "adm-prohibited": "admin-prohib";
123 fw3_load_defaults(struct fw3_state *state, struct uci_package *p)
125 struct uci_section *s;
126 struct uci_element *e;
127 struct fw3_defaults *defs = &state->defaults;
129 bool flow_offload_avaliable = false;
132 defs->tcp_reject_code = FW3_REJECT_CODE_TCP_RESET;
133 defs->any_reject_code = FW3_REJECT_CODE_PORT_UNREACH;
134 defs->syn_flood_rate.rate = 25;
135 defs->syn_flood_rate.burst = 50;
136 defs->tcp_syncookies = true;
137 defs->tcp_window_scaling = true;
138 defs->custom_chains = true;
139 defs->auto_helper = true;
141 uci_foreach_element(&p->sections, e)
143 s = uci_to_section(e);
145 if (strcmp(s->type, "defaults"))
150 warn_elem(e, "ignoring duplicate section");
154 if(!fw3_parse_options(&state->defaults, fw3_flag_opts, s))
155 warn_elem(e, "has invalid options");
157 check_policy(e, &defs->policy_input, "input");
158 check_policy(e, &defs->policy_output, "output");
159 check_policy(e, &defs->policy_forward, "forward");
161 check_any_reject_code(e, &defs->any_reject_code);
163 /* exists in both ipv4 and ipv6, if at all, so only check ipv4 */
164 check_target(e, &flow_offload_avaliable, "FLOWOFFLOAD", false);
166 if (!flow_offload_avaliable)
167 defs->flow_offloading = false;
172 fw3_print_default_chains(struct fw3_ipt_handle *handle, struct fw3_state *state,
175 struct fw3_defaults *defs = &state->defaults;
176 const struct fw3_chain_spec *c;
179 ((t == FW3_FLAG_REJECT) ? FW3_FLAG_DROP : t)
181 if (handle->family == FW3_FAMILY_V6 && defs->disable_ipv6)
184 if (handle->table == FW3_TABLE_FILTER)
186 fw3_ipt_set_policy(handle, "INPUT", policy(defs->policy_input));
187 fw3_ipt_set_policy(handle, "OUTPUT", policy(defs->policy_output));
188 fw3_ipt_set_policy(handle, "FORWARD", policy(defs->policy_forward));
191 if (defs->custom_chains)
192 set(defs->flags, handle->family, FW3_FLAG_CUSTOM_CHAINS);
195 set(defs->flags, handle->family, FW3_FLAG_SYN_FLOOD);
197 for (c = default_chains; c->format; c++)
199 if (!fw3_is_family(c, handle->family))
202 if (c->table != handle->table)
206 !fw3_hasbit(defs->flags[handle->family == FW3_FAMILY_V6], c->flag))
209 fw3_ipt_create_chain(handle, reload, c->format);
212 set(defs->flags, handle->family, handle->table);
216 fw3_print_default_head_rules(struct fw3_ipt_handle *handle,
217 struct fw3_state *state, bool reload)
220 struct fw3_defaults *defs = &state->defaults;
221 struct fw3_device lodev = { .set = true, .name = "lo" };
222 struct fw3_protocol tcp = { .protocol = 6 };
223 struct fw3_ipt_rule *r;
225 const char *chains[] = {
228 "FORWARD", "forwarding",
231 switch (handle->table)
233 case FW3_TABLE_FILTER:
235 r = fw3_ipt_rule_create(handle, NULL, &lodev, NULL, NULL, NULL);
236 fw3_ipt_rule_target(r, "ACCEPT");
237 fw3_ipt_rule_append(r, "INPUT");
239 r = fw3_ipt_rule_create(handle, NULL, NULL, &lodev, NULL, NULL);
240 fw3_ipt_rule_target(r, "ACCEPT");
241 fw3_ipt_rule_append(r, "OUTPUT");
243 if (defs->custom_chains)
245 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
247 r = fw3_ipt_rule_new(handle);
248 fw3_ipt_rule_comment(r, "Custom %s rule chain", chains[i+1]);
249 fw3_ipt_rule_target(r, "%s_rule", chains[i+1]);
250 fw3_ipt_rule_append(r, chains[i]);
254 if (defs->flow_offloading)
256 r = fw3_ipt_rule_new(handle);
257 fw3_ipt_rule_comment(r, "Traffic offloading");
258 fw3_ipt_rule_extra(r, "-m conntrack --ctstate RELATED,ESTABLISHED");
259 fw3_ipt_rule_target(r, "FLOWOFFLOAD");
260 if (defs->flow_offloading_hw)
261 fw3_ipt_rule_addarg(r, false, "--hw", NULL);
262 fw3_ipt_rule_append(r, "FORWARD");
265 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
267 r = fw3_ipt_rule_new(handle);
268 fw3_ipt_rule_extra(r, "-m conntrack --ctstate RELATED,ESTABLISHED");
269 fw3_ipt_rule_target(r, "ACCEPT");
270 fw3_ipt_rule_append(r, chains[i]);
272 if (defs->drop_invalid)
274 r = fw3_ipt_rule_new(handle);
275 fw3_ipt_rule_extra(r, "-m conntrack --ctstate INVALID");
276 fw3_ipt_rule_target(r, "DROP");
277 fw3_ipt_rule_append(r, chains[i]);
283 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
284 fw3_ipt_rule_extra(r, "--syn");
285 fw3_ipt_rule_limit(r, &defs->syn_flood_rate);
286 fw3_ipt_rule_target(r, "RETURN");
287 fw3_ipt_rule_append(r, "syn_flood");
289 r = fw3_ipt_rule_new(handle);
290 fw3_ipt_rule_target(r, "DROP");
291 fw3_ipt_rule_append(r, "syn_flood");
293 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
294 fw3_ipt_rule_extra(r, "--syn");
295 fw3_ipt_rule_target(r, "syn_flood");
296 fw3_ipt_rule_append(r, "INPUT");
299 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
300 fw3_ipt_rule_target(r, "REJECT");
301 fw3_ipt_rule_addarg(r, false, "--reject-with", get_reject_code(handle->family, defs->tcp_reject_code));
302 fw3_ipt_rule_append(r, "reject");
304 r = fw3_ipt_rule_new(handle);
305 fw3_ipt_rule_target(r, "REJECT");
306 fw3_ipt_rule_addarg(r, false, "--reject-with", get_reject_code(handle->family, defs->any_reject_code));
307 fw3_ipt_rule_append(r, "reject");
312 if (defs->custom_chains)
314 r = fw3_ipt_rule_new(handle);
315 fw3_ipt_rule_comment(r, "Custom prerouting rule chain");
316 fw3_ipt_rule_target(r, "prerouting_rule");
317 fw3_ipt_rule_append(r, "PREROUTING");
319 r = fw3_ipt_rule_new(handle);
320 fw3_ipt_rule_comment(r, "Custom postrouting rule chain");
321 fw3_ipt_rule_target(r, "postrouting_rule");
322 fw3_ipt_rule_append(r, "POSTROUTING");
332 fw3_print_default_tail_rules(struct fw3_ipt_handle *handle,
333 struct fw3_state *state, bool reload)
335 struct fw3_defaults *defs = &state->defaults;
336 struct fw3_ipt_rule *r;
338 if (handle->table != FW3_TABLE_FILTER)
341 if (defs->policy_input == FW3_FLAG_REJECT)
343 r = fw3_ipt_rule_new(handle);
348 fw3_ipt_rule_target(r, "reject");
349 fw3_ipt_rule_append(r, "INPUT");
352 if (defs->policy_output == FW3_FLAG_REJECT)
354 r = fw3_ipt_rule_new(handle);
359 fw3_ipt_rule_target(r, "reject");
360 fw3_ipt_rule_append(r, "OUTPUT");
363 if (defs->policy_forward == FW3_FLAG_REJECT)
365 r = fw3_ipt_rule_new(handle);
370 fw3_ipt_rule_target(r, "reject");
371 fw3_ipt_rule_append(r, "FORWARD");
376 set_default(const char *name, int set)
379 char path[sizeof("/proc/sys/net/ipv4/tcp_window_scaling")];
381 snprintf(path, sizeof(path), "/proc/sys/net/ipv4/tcp_%s", name);
383 info(" * Set tcp_%s to %s", name, set ? "on" : "off");
385 if (!(f = fopen(path, "w")))
387 info(" ! Unable to write value: %s", strerror(errno));
391 fprintf(f, "%u\n", set);
396 fw3_set_defaults(struct fw3_state *state)
398 set_default("ecn", state->defaults.tcp_ecn);
399 set_default("syncookies", state->defaults.tcp_syncookies);
400 set_default("window_scaling", state->defaults.tcp_window_scaling);
404 fw3_flush_rules(struct fw3_ipt_handle *handle, struct fw3_state *state,
407 enum fw3_flag policy = reload ? FW3_FLAG_DROP : FW3_FLAG_ACCEPT;
408 struct fw3_defaults *defs = &state->defaults;
409 const struct fw3_chain_spec *c;
411 if (!has(defs->flags, handle->family, handle->table))
414 if (handle->table == FW3_TABLE_FILTER)
416 fw3_ipt_set_policy(handle, "INPUT", policy);
417 fw3_ipt_set_policy(handle, "OUTPUT", policy);
418 fw3_ipt_set_policy(handle, "FORWARD", policy);
421 fw3_ipt_delete_id_rules(handle, "INPUT");
422 fw3_ipt_delete_id_rules(handle, "OUTPUT");
423 fw3_ipt_delete_id_rules(handle, "FORWARD");
424 fw3_ipt_delete_id_rules(handle, "PREROUTING");
425 fw3_ipt_delete_id_rules(handle, "POSTROUTING");
427 /* first flush all the rules ... */
428 for (c = default_chains; c->format; c++)
430 /* don't touch user chains on selective stop */
431 if (reload && c->flag == FW3_FLAG_CUSTOM_CHAINS)
434 if (!fw3_is_family(c, handle->family))
437 if (c->table != handle->table)
440 if (c->flag && !has(defs->flags, handle->family, c->flag))
443 fw3_ipt_flush_chain(handle, c->format);
446 /* ... then remove the chains */
447 for (c = default_chains; c->format; c++)
449 if (!fw3_is_family(c, handle->family))
452 if (c->table != handle->table)
455 if (c->flag && !has(defs->flags, handle->family, c->flag))
458 fw3_ipt_delete_chain(handle, reload, c->format);
461 del(defs->flags, handle->family, handle->table);
465 fw3_flush_all(struct fw3_ipt_handle *handle)
467 if (handle->table == FW3_TABLE_FILTER)
469 fw3_ipt_set_policy(handle, "INPUT", FW3_FLAG_ACCEPT);
470 fw3_ipt_set_policy(handle, "OUTPUT", FW3_FLAG_ACCEPT);
471 fw3_ipt_set_policy(handle, "FORWARD", FW3_FLAG_ACCEPT);
474 fw3_ipt_flush(handle);