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, name) \
23 { FW3_FAMILY_##f, FW3_TABLE_##tbl, FW3_DEFAULT_##def, name }
26 enum fw3_family family;
28 enum fw3_default flag;
32 static const struct chain default_chains[] = {
33 C(ANY, FILTER, UNSPEC, "delegate_input"),
34 C(ANY, FILTER, UNSPEC, "delegate_output"),
35 C(ANY, FILTER, UNSPEC, "delegate_forward"),
36 C(ANY, FILTER, UNSPEC, "reject"),
37 C(ANY, FILTER, CUSTOM_CHAINS, "input_rule"),
38 C(ANY, FILTER, CUSTOM_CHAINS, "output_rule"),
39 C(ANY, FILTER, CUSTOM_CHAINS, "forwarding_rule"),
40 C(ANY, FILTER, SYN_FLOOD, "syn_flood"),
42 C(V4, NAT, UNSPEC, "delegate_prerouting"),
43 C(V4, NAT, UNSPEC, "delegate_postrouting"),
44 C(V4, NAT, CUSTOM_CHAINS, "prerouting_rule"),
45 C(V4, NAT, CUSTOM_CHAINS, "postrouting_rule"),
47 C(ANY, MANGLE, UNSPEC, "mssfix"),
48 C(ANY, RAW, UNSPEC, "notrack"),
51 static const struct chain toplevel_rules[] = {
52 C(ANY, FILTER, UNSPEC, "INPUT -j delegate_input"),
53 C(ANY, FILTER, UNSPEC, "OUTPUT -j delegate_output"),
54 C(ANY, FILTER, UNSPEC, "FORWARD -j delegate_forward"),
56 C(V4, NAT, UNSPEC, "PREROUTING -j delegate_prerouting"),
57 C(V4, NAT, UNSPEC, "POSTROUTING -j delegate_postrouting"),
59 C(ANY, MANGLE, UNSPEC, "FORWARD -j mssfix"),
60 C(ANY, RAW, UNSPEC, "PREROUTING -j notrack"),
63 const struct fw3_option fw3_default_opts[] = {
64 FW3_OPT("input", target, defaults, policy_input),
65 FW3_OPT("forward", target, defaults, policy_forward),
66 FW3_OPT("output", target, defaults, policy_output),
68 FW3_OPT("drop_invalid", bool, defaults, drop_invalid),
70 FW3_OPT("syn_flood", bool, defaults, syn_flood),
71 FW3_OPT("synflood_protect", bool, defaults, syn_flood),
72 FW3_OPT("synflood_rate", limit, defaults, syn_flood_rate),
73 FW3_OPT("synflood_burst", int, defaults, syn_flood_rate.burst),
75 FW3_OPT("tcp_syncookies", bool, defaults, tcp_syncookies),
76 FW3_OPT("tcp_ecn", bool, defaults, tcp_ecn),
77 FW3_OPT("tcp_window_scaling", bool, defaults, tcp_window_scaling),
79 FW3_OPT("accept_redirects", bool, defaults, accept_redirects),
80 FW3_OPT("accept_source_route", bool, defaults, accept_source_route),
82 FW3_OPT("custom_chains", bool, defaults, custom_chains),
83 FW3_OPT("disable_ipv6", bool, defaults, disable_ipv6),
90 print_chains(enum fw3_table table, enum fw3_family family,
91 const char *fmt, uint32_t *flags, uint32_t mask,
92 const struct chain *chains, int n)
95 const struct chain *c;
96 uint32_t f = flags ? flags[family == FW3_FAMILY_V6] : 0;
101 for (c = chains; n > 0; c++, n--)
103 if (!fw3_is_family(c, family))
106 if (c->table != table)
109 if ((c->flag != FW3_DEFAULT_UNSPEC) && !hasbit(f, c->flag))
112 fw3_pr(fmt, c->name);
121 check_policy(struct uci_element *e, enum fw3_target *pol, const char *name)
123 if (*pol == FW3_TARGET_UNSPEC)
125 warn_elem(e, "has no %s policy specified, defaulting to DROP", name);
126 *pol = FW3_TARGET_DROP;
128 else if (*pol > FW3_TARGET_DROP)
130 warn_elem(e, "has invalid %s policy, defaulting to DROP", name);
131 *pol = FW3_TARGET_DROP;
136 fw3_load_defaults(struct fw3_state *state, struct uci_package *p)
138 struct uci_section *s;
139 struct uci_element *e;
140 struct fw3_defaults *defs = &state->defaults;
144 defs->syn_flood_rate.rate = 25;
145 defs->syn_flood_rate.burst = 50;
146 defs->tcp_syncookies = true;
147 defs->tcp_window_scaling = true;
148 defs->custom_chains = true;
150 uci_foreach_element(&p->sections, e)
152 s = uci_to_section(e);
154 if (strcmp(s->type, "defaults"))
159 warn_elem(e, "ignoring duplicate section");
163 fw3_parse_options(&state->defaults, fw3_default_opts, s);
165 check_policy(e, &defs->policy_input, "input");
166 check_policy(e, &defs->policy_output, "output");
167 check_policy(e, &defs->policy_forward, "forward");
172 fw3_print_default_chains(enum fw3_table table, enum fw3_family family,
173 bool reload, struct fw3_state *state)
176 struct fw3_defaults *defs = &state->defaults;
177 uint32_t custom_mask = ~0;
180 ((t == FW3_TARGET_REJECT) ? "DROP" : fw3_flag_names[t])
182 if (family == FW3_FAMILY_V6 && defs->disable_ipv6)
185 if (table == FW3_TABLE_FILTER)
187 fw3_pr(":INPUT %s [0:0]\n", policy(defs->policy_input));
188 fw3_pr(":FORWARD %s [0:0]\n", policy(defs->policy_forward));
189 fw3_pr(":OUTPUT %s [0:0]\n", policy(defs->policy_output));
192 /* Don't touch user chains on reload */
194 delbit(custom_mask, FW3_DEFAULT_CUSTOM_CHAINS);
196 if (defs->custom_chains)
197 set(defs->flags, family, FW3_DEFAULT_CUSTOM_CHAINS);
200 set(defs->flags, family, FW3_DEFAULT_SYN_FLOOD);
202 rv = print_chains(table, family, ":%s - [0:0]\n", defs->flags, custom_mask,
203 default_chains, ARRAY_SIZE(default_chains));
206 set(defs->flags, family, table);
210 fw3_print_default_head_rules(enum fw3_table table, enum fw3_family family,
211 bool reload, struct fw3_state *state)
214 struct fw3_defaults *defs = &state->defaults;
215 const char *chains[] = {
218 "forward", "forwarding",
221 print_chains(table, family, "-A %s\n", NULL, 0,
222 toplevel_rules, ARRAY_SIZE(toplevel_rules));
226 case FW3_TABLE_FILTER:
227 fw3_pr("-A delegate_input -i lo -j ACCEPT\n");
228 fw3_pr("-A delegate_output -o lo -j ACCEPT\n");
230 if (defs->custom_chains)
232 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
234 fw3_pr("-A delegate_%s -m comment "
235 "--comment \"user chain for %s\" -j %s_rule\n",
236 chains[i], chains[i+1], chains[i+1]);
240 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
242 fw3_pr("-A delegate_%s -m conntrack --ctstate RELATED,ESTABLISHED "
243 "-j ACCEPT\n", chains[i]);
245 if (defs->drop_invalid)
247 fw3_pr("-A delegate_%s -m conntrack --ctstate INVALID -j DROP\n",
254 fw3_pr("-A syn_flood -p tcp --syn");
255 fw3_format_limit(&defs->syn_flood_rate);
256 fw3_pr(" -j RETURN\n");
258 fw3_pr("-A syn_flood -j DROP\n");
259 fw3_pr("-A delegate_input -p tcp --syn -j syn_flood\n");
262 fw3_pr("-A reject -p tcp -j REJECT --reject-with tcp-reset\n");
263 fw3_pr("-A reject -j REJECT --reject-with port-unreach\n");
268 if (defs->custom_chains)
270 fw3_pr("-A delegate_prerouting "
271 "-m comment --comment \"user chain for prerouting\" "
272 "-j prerouting_rule\n");
274 fw3_pr("-A delegate_postrouting "
275 "-m comment --comment \"user chain for postrouting\" "
276 "-j postrouting_rule\n");
286 fw3_print_default_tail_rules(enum fw3_table table, enum fw3_family family,
287 bool reload, struct fw3_state *state)
289 struct fw3_defaults *defs = &state->defaults;
291 if (table != FW3_TABLE_FILTER)
294 if (defs->policy_input == FW3_TARGET_REJECT)
295 fw3_pr("-A delegate_input -j reject\n");
297 if (defs->policy_output == FW3_TARGET_REJECT)
298 fw3_pr("-A delegate_output -j reject\n");
300 if (defs->policy_forward == FW3_TARGET_REJECT)
301 fw3_pr("-A delegate_forward -j reject\n");
305 set_default(const char *name, bool set)
308 char path[sizeof("/proc/sys/net/ipv4/tcp_window_scaling\0")];
310 snprintf(path, sizeof(path), "/proc/sys/net/ipv4/tcp_%s", name);
312 info(" * Set tcp_%s to %s", name, set ? "on" : "off", name);
314 if (!(f = fopen(path, "w")))
316 info(" ! Unable to write value: %s", strerror(errno));
320 fprintf(f, "%u\n", set);
325 fw3_set_defaults(struct fw3_state *state)
327 set_default("ecn", state->defaults.tcp_ecn);
328 set_default("syncookies", state->defaults.tcp_syncookies);
329 set_default("window_scaling", state->defaults.tcp_window_scaling);
333 reset_policy(enum fw3_table table, enum fw3_target policy)
335 if (table != FW3_TABLE_FILTER)
338 fw3_pr(":INPUT %s [0:0]\n", fw3_flag_names[policy]);
339 fw3_pr(":OUTPUT %s [0:0]\n", fw3_flag_names[policy]);
340 fw3_pr(":FORWARD %s [0:0]\n", fw3_flag_names[policy]);
344 fw3_flush_rules(enum fw3_table table, enum fw3_family family,
345 bool pass2, bool reload, struct fw3_state *state)
347 struct fw3_defaults *defs = &state->defaults;
348 uint32_t custom_mask = ~0;
350 if (!has(defs->flags, family, table))
353 /* don't touch user chains on selective stop */
355 delbit(custom_mask, FW3_DEFAULT_CUSTOM_CHAINS);
359 reset_policy(table, reload ? FW3_TARGET_DROP : FW3_TARGET_ACCEPT);
361 print_chains(table, family, "-D %s\n",
362 defs->flags, custom_mask,
363 toplevel_rules, ARRAY_SIZE(toplevel_rules));
365 print_chains(table, family, "-F %s\n",
366 defs->flags, custom_mask,
367 default_chains, ARRAY_SIZE(default_chains));
371 print_chains(table, family, "-X %s\n",
372 defs->flags, custom_mask,
373 default_chains, ARRAY_SIZE(default_chains));
375 del(defs->flags, family, table);
380 fw3_flush_all(enum fw3_table table)
382 reset_policy(table, FW3_TARGET_ACCEPT);