2 * firewall3 - 3rd OpenWrt UCI firewall implementation
4 * Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org>
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, "delegate_input"),
27 C(ANY, FILTER, UNSPEC, "delegate_output"),
28 C(ANY, FILTER, UNSPEC, "delegate_forward"),
29 C(ANY, FILTER, UNSPEC, "reject"),
30 C(ANY, FILTER, CUSTOM_CHAINS, "input_rule"),
31 C(ANY, FILTER, CUSTOM_CHAINS, "output_rule"),
32 C(ANY, FILTER, CUSTOM_CHAINS, "forwarding_rule"),
33 C(ANY, FILTER, SYN_FLOOD, "syn_flood"),
35 C(V4, NAT, UNSPEC, "delegate_prerouting"),
36 C(V4, NAT, UNSPEC, "delegate_postrouting"),
37 C(V4, NAT, CUSTOM_CHAINS, "prerouting_rule"),
38 C(V4, NAT, CUSTOM_CHAINS, "postrouting_rule"),
40 C(ANY, MANGLE, UNSPEC, "mssfix"),
41 C(ANY, MANGLE, UNSPEC, "fwmark"),
43 C(ANY, RAW, UNSPEC, "delegate_notrack"),
48 const struct fw3_option fw3_flag_opts[] = {
49 FW3_OPT("input", target, defaults, policy_input),
50 FW3_OPT("forward", target, defaults, policy_forward),
51 FW3_OPT("output", target, defaults, policy_output),
53 FW3_OPT("drop_invalid", bool, defaults, drop_invalid),
55 FW3_OPT("syn_flood", bool, defaults, syn_flood),
56 FW3_OPT("synflood_protect", bool, defaults, syn_flood),
57 FW3_OPT("synflood_rate", limit, defaults, syn_flood_rate),
58 FW3_OPT("synflood_burst", int, defaults, syn_flood_rate.burst),
60 FW3_OPT("tcp_syncookies", bool, defaults, tcp_syncookies),
61 FW3_OPT("tcp_ecn", int, defaults, tcp_ecn),
62 FW3_OPT("tcp_window_scaling", bool, defaults, tcp_window_scaling),
64 FW3_OPT("accept_redirects", bool, defaults, accept_redirects),
65 FW3_OPT("accept_source_route", bool, defaults, accept_source_route),
67 FW3_OPT("custom_chains", bool, defaults, custom_chains),
68 FW3_OPT("disable_ipv6", bool, defaults, disable_ipv6),
70 FW3_OPT("__flags_v4", int, defaults, flags[0]),
71 FW3_OPT("__flags_v6", int, defaults, flags[1]),
78 check_policy(struct uci_element *e, enum fw3_flag *pol, const char *name)
80 if (*pol == FW3_FLAG_UNSPEC)
82 warn_elem(e, "has no %s policy specified, defaulting to DROP", name);
85 else if (*pol > FW3_FLAG_DROP)
87 warn_elem(e, "has invalid %s policy, defaulting to DROP", name);
93 fw3_load_defaults(struct fw3_state *state, struct uci_package *p)
95 struct uci_section *s;
96 struct uci_element *e;
97 struct fw3_defaults *defs = &state->defaults;
101 defs->syn_flood_rate.rate = 25;
102 defs->syn_flood_rate.burst = 50;
103 defs->tcp_syncookies = true;
104 defs->tcp_window_scaling = true;
105 defs->custom_chains = true;
107 uci_foreach_element(&p->sections, e)
109 s = uci_to_section(e);
111 if (strcmp(s->type, "defaults"))
116 warn_elem(e, "ignoring duplicate section");
120 fw3_parse_options(&state->defaults, fw3_flag_opts, s);
122 check_policy(e, &defs->policy_input, "input");
123 check_policy(e, &defs->policy_output, "output");
124 check_policy(e, &defs->policy_forward, "forward");
129 fw3_print_default_chains(struct fw3_ipt_handle *handle, struct fw3_state *state,
132 struct fw3_defaults *defs = &state->defaults;
133 const struct fw3_chain_spec *c;
136 ((t == FW3_FLAG_REJECT) ? FW3_FLAG_DROP : t)
138 if (handle->family == FW3_FAMILY_V6 && defs->disable_ipv6)
141 if (handle->table == FW3_TABLE_FILTER)
143 fw3_ipt_set_policy(handle, "INPUT", policy(defs->policy_input));
144 fw3_ipt_set_policy(handle, "OUTPUT", policy(defs->policy_output));
145 fw3_ipt_set_policy(handle, "FORWARD", policy(defs->policy_forward));
148 if (defs->custom_chains)
149 set(defs->flags, handle->family, FW3_FLAG_CUSTOM_CHAINS);
152 set(defs->flags, handle->family, FW3_FLAG_SYN_FLOOD);
154 for (c = default_chains; c->format; c++)
156 /* don't touch user chains on selective stop */
157 if (reload && c->flag == FW3_FLAG_CUSTOM_CHAINS)
160 if (!fw3_is_family(c, handle->family))
163 if (c->table != handle->table)
167 !hasbit(defs->flags[handle->family == FW3_FAMILY_V6], c->flag))
170 fw3_ipt_create_chain(handle, c->format);
173 set(defs->flags, handle->family, handle->table);
177 struct toplevel_rule {
178 enum fw3_table table;
184 fw3_print_default_head_rules(struct fw3_ipt_handle *handle,
185 struct fw3_state *state, bool reload)
188 struct fw3_defaults *defs = &state->defaults;
189 struct fw3_device lodev = { .set = true };
190 struct fw3_protocol tcp = { .protocol = 6 };
191 struct fw3_ipt_rule *r;
192 struct toplevel_rule *tr;
194 const char *chains[] = {
195 "delegate_input", "input",
196 "delegate_output", "output",
197 "delegate_forward", "forwarding",
200 struct toplevel_rule rules[] = {
201 { FW3_TABLE_FILTER, "INPUT", "delegate_input" },
202 { FW3_TABLE_FILTER, "OUTPUT", "delegate_output" },
203 { FW3_TABLE_FILTER, "FORWARD", "delegate_forward" },
205 { FW3_TABLE_NAT, "PREROUTING", "delegate_prerouting" },
206 { FW3_TABLE_NAT, "POSTROUTING", "delegate_postrouting" },
208 { FW3_TABLE_MANGLE, "FORWARD", "mssfix" },
209 { FW3_TABLE_MANGLE, "PREROUTING", "fwmark" },
211 { FW3_TABLE_RAW, "PREROUTING", "delegate_notrack" },
216 for (tr = rules; tr->chain; tr++)
218 if (tr->table != handle->table)
221 r = fw3_ipt_rule_new(handle);
222 fw3_ipt_rule_target(r, tr->target);
223 fw3_ipt_rule_replace(r, tr->chain);
226 switch (handle->table)
228 case FW3_TABLE_FILTER:
230 sprintf(lodev.name, "lo");
232 r = fw3_ipt_rule_create(handle, NULL, &lodev, NULL, NULL, NULL);
233 fw3_ipt_rule_target(r, "ACCEPT");
234 fw3_ipt_rule_append(r, "delegate_input");
236 r = fw3_ipt_rule_create(handle, NULL, NULL, &lodev, NULL, NULL);
237 fw3_ipt_rule_target(r, "ACCEPT");
238 fw3_ipt_rule_append(r, "delegate_output");
240 if (defs->custom_chains)
242 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
244 r = fw3_ipt_rule_new(handle);
245 fw3_ipt_rule_comment(r, "user chain for %s", chains[i+1]);
246 fw3_ipt_rule_target(r, "%s_rule", chains[i+1]);
247 fw3_ipt_rule_append(r, chains[i]);
251 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
253 r = fw3_ipt_rule_new(handle);
254 fw3_ipt_rule_extra(r, "-m conntrack --ctstate RELATED,ESTABLISHED");
255 fw3_ipt_rule_target(r, "ACCEPT");
256 fw3_ipt_rule_append(r, chains[i]);
258 if (defs->drop_invalid)
260 r = fw3_ipt_rule_new(handle);
261 fw3_ipt_rule_extra(r, "-m conntrack --ctstate INVALID");
262 fw3_ipt_rule_target(r, "DROP");
263 fw3_ipt_rule_append(r, chains[i]);
269 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
270 fw3_ipt_rule_extra(r, "--syn");
271 fw3_ipt_rule_limit(r, &defs->syn_flood_rate);
272 fw3_ipt_rule_target(r, "RETURN");
273 fw3_ipt_rule_append(r, "syn_flood");
275 r = fw3_ipt_rule_new(handle);
276 fw3_ipt_rule_target(r, "DROP");
277 fw3_ipt_rule_append(r, "syn_flood");
279 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
280 fw3_ipt_rule_extra(r, "--syn");
281 fw3_ipt_rule_target(r, "syn_flood");
282 fw3_ipt_rule_append(r, "delegate_input");
285 r = fw3_ipt_rule_create(handle, &tcp, NULL, NULL, NULL, NULL);
286 fw3_ipt_rule_target(r, "REJECT");
287 fw3_ipt_rule_addarg(r, false, "--reject-with", "tcp-reset");
288 fw3_ipt_rule_append(r, "reject");
290 r = fw3_ipt_rule_new(handle);
291 fw3_ipt_rule_target(r, "REJECT");
292 fw3_ipt_rule_addarg(r, false, "--reject-with", "port-unreach");
293 fw3_ipt_rule_append(r, "reject");
298 if (defs->custom_chains)
300 r = fw3_ipt_rule_new(handle);
301 fw3_ipt_rule_comment(r, "user chain for prerouting");
302 fw3_ipt_rule_target(r, "prerouting_rule");
303 fw3_ipt_rule_append(r, "delegate_prerouting");
305 r = fw3_ipt_rule_new(handle);
306 fw3_ipt_rule_comment(r, "user chain for postrouting");
307 fw3_ipt_rule_target(r, "postrouting_rule");
308 fw3_ipt_rule_append(r, "delegate_postrouting");
318 fw3_print_default_tail_rules(struct fw3_ipt_handle *handle,
319 struct fw3_state *state, bool reload)
321 struct fw3_defaults *defs = &state->defaults;
322 struct fw3_ipt_rule *r;
324 if (handle->table != FW3_TABLE_FILTER)
327 if (defs->policy_input == FW3_FLAG_REJECT)
329 r = fw3_ipt_rule_new(handle);
334 fw3_ipt_rule_target(r, "reject");
335 fw3_ipt_rule_append(r, "delegate_input");
338 if (defs->policy_output == FW3_FLAG_REJECT)
340 r = fw3_ipt_rule_new(handle);
345 fw3_ipt_rule_target(r, "reject");
346 fw3_ipt_rule_append(r, "delegate_output");
349 if (defs->policy_forward == FW3_FLAG_REJECT)
351 r = fw3_ipt_rule_new(handle);
356 fw3_ipt_rule_target(r, "reject");
357 fw3_ipt_rule_append(r, "delegate_forward");
362 set_default(const char *name, int set)
365 char path[sizeof("/proc/sys/net/ipv4/tcp_window_scaling\0")];
367 snprintf(path, sizeof(path), "/proc/sys/net/ipv4/tcp_%s", name);
369 info(" * Set tcp_%s to %s", name, set ? "on" : "off", name);
371 if (!(f = fopen(path, "w")))
373 info(" ! Unable to write value: %s", strerror(errno));
377 fprintf(f, "%u\n", set);
382 fw3_set_defaults(struct fw3_state *state)
384 set_default("ecn", state->defaults.tcp_ecn);
385 set_default("syncookies", state->defaults.tcp_syncookies);
386 set_default("window_scaling", state->defaults.tcp_window_scaling);
390 fw3_flush_rules(struct fw3_ipt_handle *handle, struct fw3_state *state,
393 enum fw3_flag policy = reload ? FW3_FLAG_DROP : FW3_FLAG_ACCEPT;
394 struct fw3_defaults *defs = &state->defaults;
395 const struct fw3_chain_spec *c;
397 if (!has(defs->flags, handle->family, handle->table))
400 if (handle->table == FW3_TABLE_FILTER)
402 fw3_ipt_set_policy(handle, "INPUT", policy);
403 fw3_ipt_set_policy(handle, "OUTPUT", policy);
404 fw3_ipt_set_policy(handle, "FORWARD", policy);
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);