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),
45 FW3_OPT("syn_flood", bool, defaults, syn_flood),
46 FW3_OPT("synflood_protect", bool, defaults, syn_flood),
47 FW3_OPT("synflood_rate", limit, defaults, syn_flood_rate),
48 FW3_OPT("synflood_burst", int, defaults, syn_flood_rate.burst),
50 FW3_OPT("tcp_syncookies", bool, defaults, tcp_syncookies),
51 FW3_OPT("tcp_ecn", int, defaults, tcp_ecn),
52 FW3_OPT("tcp_window_scaling", bool, defaults, tcp_window_scaling),
54 FW3_OPT("accept_redirects", bool, defaults, accept_redirects),
55 FW3_OPT("accept_source_route", bool, defaults, accept_source_route),
57 FW3_OPT("auto_helper", bool, defaults, auto_helper),
58 FW3_OPT("custom_chains", bool, defaults, custom_chains),
59 FW3_OPT("disable_ipv6", bool, defaults, disable_ipv6),
60 FW3_OPT("flow_offloading", bool, defaults, flow_offloading),
61 FW3_OPT("flow_offloading_hw", bool, defaults, flow_offloading_hw),
63 FW3_OPT("__flags_v4", int, defaults, flags[0]),
64 FW3_OPT("__flags_v6", int, defaults, flags[1]),
71 check_policy(struct uci_element *e, enum fw3_flag *pol, const char *name)
73 if (*pol == FW3_FLAG_UNSPEC)
75 warn_elem(e, "has no %s policy specified, defaulting to DROP", name);
78 else if (*pol > FW3_FLAG_DROP)
80 warn_elem(e, "has invalid %s policy, defaulting to DROP", name);
86 check_offloading(struct uci_element *e, bool *offloading)
93 f = fopen("/sys/module/xt_FLOWOFFLOAD/refcnt", "r");
101 warn_elem(e, "enables offloading but missing kernel support, disabling");
106 fw3_load_defaults(struct fw3_state *state, struct uci_package *p)
108 struct uci_section *s;
109 struct uci_element *e;
110 struct fw3_defaults *defs = &state->defaults;
114 defs->syn_flood_rate.rate = 25;
115 defs->syn_flood_rate.burst = 50;
116 defs->tcp_syncookies = true;
117 defs->tcp_window_scaling = true;
118 defs->custom_chains = true;
119 defs->auto_helper = true;
121 uci_foreach_element(&p->sections, e)
123 s = uci_to_section(e);
125 if (strcmp(s->type, "defaults"))
130 warn_elem(e, "ignoring duplicate section");
134 if(!fw3_parse_options(&state->defaults, fw3_flag_opts, s))
135 warn_elem(e, "has invalid options");
137 check_policy(e, &defs->policy_input, "input");
138 check_policy(e, &defs->policy_output, "output");
139 check_policy(e, &defs->policy_forward, "forward");
141 check_offloading(e, &defs->flow_offloading);
146 fw3_print_default_chains(struct fw3_ipt_handle *handle, struct fw3_state *state,
149 struct fw3_defaults *defs = &state->defaults;
150 const struct fw3_chain_spec *c;
153 ((t == FW3_FLAG_REJECT) ? FW3_FLAG_DROP : t)
155 if (handle->family == FW3_FAMILY_V6 && defs->disable_ipv6)
158 if (handle->table == FW3_TABLE_FILTER)
160 fw3_ipt_set_policy(handle, "INPUT", policy(defs->policy_input));
161 fw3_ipt_set_policy(handle, "OUTPUT", policy(defs->policy_output));
162 fw3_ipt_set_policy(handle, "FORWARD", policy(defs->policy_forward));
165 if (defs->custom_chains)
166 set(defs->flags, handle->family, FW3_FLAG_CUSTOM_CHAINS);
169 set(defs->flags, handle->family, FW3_FLAG_SYN_FLOOD);
171 for (c = default_chains; c->format; c++)
173 /* don't touch user chains on selective stop */
174 if (reload && c->flag == FW3_FLAG_CUSTOM_CHAINS)
177 if (!fw3_is_family(c, handle->family))
180 if (c->table != handle->table)
184 !fw3_hasbit(defs->flags[handle->family == FW3_FAMILY_V6], c->flag))
187 fw3_ipt_create_chain(handle, c->format);
190 set(defs->flags, handle->family, handle->table);
194 fw3_print_default_head_rules(struct fw3_ipt_handle *handle,
195 struct fw3_state *state, bool reload)
198 struct fw3_defaults *defs = &state->defaults;
199 struct fw3_device lodev = { .set = true };
200 struct fw3_protocol tcp = { .protocol = 6 };
201 struct fw3_ipt_rule *r;
203 const char *chains[] = {
206 "FORWARD", "forwarding",
209 switch (handle->table)
211 case FW3_TABLE_FILTER:
213 sprintf(lodev.name, "lo");
215 r = fw3_ipt_rule_create(handle, NULL, &lodev, NULL, NULL, NULL);
216 fw3_ipt_rule_target(r, "ACCEPT");
217 fw3_ipt_rule_append(r, "INPUT");
219 r = fw3_ipt_rule_create(handle, NULL, NULL, &lodev, NULL, NULL);
220 fw3_ipt_rule_target(r, "ACCEPT");
221 fw3_ipt_rule_append(r, "OUTPUT");
223 if (defs->custom_chains)
225 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
227 r = fw3_ipt_rule_new(handle);
228 fw3_ipt_rule_comment(r, "Custom %s rule chain", chains[i+1]);
229 fw3_ipt_rule_target(r, "%s_rule", chains[i+1]);
230 fw3_ipt_rule_append(r, chains[i]);
234 if (defs->flow_offloading)
236 r = fw3_ipt_rule_new(handle);
237 fw3_ipt_rule_comment(r, "Traffic offloading");
238 fw3_ipt_rule_extra(r, "-m conntrack --ctstate RELATED,ESTABLISHED");
239 fw3_ipt_rule_target(r, "FLOWOFFLOAD");
240 if (defs->flow_offloading_hw)
241 fw3_ipt_rule_addarg(r, false, "--hw", NULL);
242 fw3_ipt_rule_append(r, "FORWARD");
245 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
247 r = fw3_ipt_rule_new(handle);
248 fw3_ipt_rule_extra(r, "-m conntrack --ctstate RELATED,ESTABLISHED");
249 fw3_ipt_rule_target(r, "ACCEPT");
250 fw3_ipt_rule_append(r, chains[i]);
252 if (defs->drop_invalid)
254 r = fw3_ipt_rule_new(handle);
255 fw3_ipt_rule_extra(r, "-m conntrack --ctstate INVALID");
256 fw3_ipt_rule_target(r, "DROP");
257 fw3_ipt_rule_append(r, chains[i]);
263 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
264 fw3_ipt_rule_extra(r, "--syn");
265 fw3_ipt_rule_limit(r, &defs->syn_flood_rate);
266 fw3_ipt_rule_target(r, "RETURN");
267 fw3_ipt_rule_append(r, "syn_flood");
269 r = fw3_ipt_rule_new(handle);
270 fw3_ipt_rule_target(r, "DROP");
271 fw3_ipt_rule_append(r, "syn_flood");
273 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
274 fw3_ipt_rule_extra(r, "--syn");
275 fw3_ipt_rule_target(r, "syn_flood");
276 fw3_ipt_rule_append(r, "INPUT");
279 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
280 fw3_ipt_rule_target(r, "REJECT");
281 fw3_ipt_rule_addarg(r, false, "--reject-with", "tcp-reset");
282 fw3_ipt_rule_append(r, "reject");
284 r = fw3_ipt_rule_new(handle);
285 fw3_ipt_rule_target(r, "REJECT");
286 fw3_ipt_rule_addarg(r, false, "--reject-with", "port-unreach");
287 fw3_ipt_rule_append(r, "reject");
292 if (defs->custom_chains)
294 r = fw3_ipt_rule_new(handle);
295 fw3_ipt_rule_comment(r, "Custom prerouting rule chain");
296 fw3_ipt_rule_target(r, "prerouting_rule");
297 fw3_ipt_rule_append(r, "PREROUTING");
299 r = fw3_ipt_rule_new(handle);
300 fw3_ipt_rule_comment(r, "Custom postrouting rule chain");
301 fw3_ipt_rule_target(r, "postrouting_rule");
302 fw3_ipt_rule_append(r, "POSTROUTING");
312 fw3_print_default_tail_rules(struct fw3_ipt_handle *handle,
313 struct fw3_state *state, bool reload)
315 struct fw3_defaults *defs = &state->defaults;
316 struct fw3_ipt_rule *r;
318 if (handle->table != FW3_TABLE_FILTER)
321 if (defs->policy_input == FW3_FLAG_REJECT)
323 r = fw3_ipt_rule_new(handle);
328 fw3_ipt_rule_target(r, "reject");
329 fw3_ipt_rule_append(r, "INPUT");
332 if (defs->policy_output == FW3_FLAG_REJECT)
334 r = fw3_ipt_rule_new(handle);
339 fw3_ipt_rule_target(r, "reject");
340 fw3_ipt_rule_append(r, "OUTPUT");
343 if (defs->policy_forward == FW3_FLAG_REJECT)
345 r = fw3_ipt_rule_new(handle);
350 fw3_ipt_rule_target(r, "reject");
351 fw3_ipt_rule_append(r, "FORWARD");
356 set_default(const char *name, int set)
359 char path[sizeof("/proc/sys/net/ipv4/tcp_window_scaling\0")];
361 snprintf(path, sizeof(path), "/proc/sys/net/ipv4/tcp_%s", name);
363 info(" * Set tcp_%s to %s", name, set ? "on" : "off", name);
365 if (!(f = fopen(path, "w")))
367 info(" ! Unable to write value: %s", strerror(errno));
371 fprintf(f, "%u\n", set);
376 fw3_set_defaults(struct fw3_state *state)
378 set_default("ecn", state->defaults.tcp_ecn);
379 set_default("syncookies", state->defaults.tcp_syncookies);
380 set_default("window_scaling", state->defaults.tcp_window_scaling);
384 fw3_flush_rules(struct fw3_ipt_handle *handle, struct fw3_state *state,
387 enum fw3_flag policy = reload ? FW3_FLAG_DROP : FW3_FLAG_ACCEPT;
388 struct fw3_defaults *defs = &state->defaults;
389 const struct fw3_chain_spec *c;
391 if (!has(defs->flags, handle->family, handle->table))
394 if (handle->table == FW3_TABLE_FILTER)
396 fw3_ipt_set_policy(handle, "INPUT", policy);
397 fw3_ipt_set_policy(handle, "OUTPUT", policy);
398 fw3_ipt_set_policy(handle, "FORWARD", policy);
401 fw3_ipt_delete_id_rules(handle, "INPUT");
402 fw3_ipt_delete_id_rules(handle, "OUTPUT");
403 fw3_ipt_delete_id_rules(handle, "FORWARD");
404 fw3_ipt_delete_id_rules(handle, "PREROUTING");
405 fw3_ipt_delete_id_rules(handle, "POSTROUTING");
407 for (c = default_chains; c->format; c++)
409 /* don't touch user chains on selective stop */
410 if (reload && c->flag == FW3_FLAG_CUSTOM_CHAINS)
413 if (!fw3_is_family(c, handle->family))
416 if (c->table != handle->table)
419 if (c->flag && !has(defs->flags, handle->family, c->flag))
422 fw3_ipt_flush_chain(handle, c->format);
424 /* keep certain basic chains that do not depend on any settings to
425 avoid purging unrelated user rules pointing to them */
426 if (reload && !c->flag)
429 fw3_ipt_delete_chain(handle, c->format);
432 del(defs->flags, handle->family, handle->table);
436 fw3_flush_all(struct fw3_ipt_handle *handle)
438 if (handle->table == FW3_TABLE_FILTER)
440 fw3_ipt_set_policy(handle, "INPUT", FW3_FLAG_ACCEPT);
441 fw3_ipt_set_policy(handle, "OUTPUT", FW3_FLAG_ACCEPT);
442 fw3_ipt_set_policy(handle, "FORWARD", FW3_FLAG_ACCEPT);
445 fw3_ipt_flush(handle);