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, CUSTOM_CHAINS, "input_rule"),
37 C(ANY, FILTER, CUSTOM_CHAINS, "output_rule"),
38 C(ANY, FILTER, CUSTOM_CHAINS, "forwarding_rule"),
39 C(ANY, FILTER, UNSPEC, "reject"),
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, uint16_t flags,
92 const struct chain *chains, int n)
95 const struct chain *c;
97 for (c = chains; n > 0; c++, n--)
99 if (!fw3_is_family(c, family))
102 if (c->table != table)
105 if ((c->flag != FW3_DEFAULT_UNSPEC) && !hasbit(flags, c->flag))
108 fw3_pr(fmt, c->name);
117 check_policy(struct uci_element *e, enum fw3_target *pol, const char *name)
119 if (*pol == FW3_TARGET_UNSPEC)
121 warn_elem(e, "has no %s policy specified, defaulting to DROP", name);
122 *pol = FW3_TARGET_DROP;
124 else if (*pol > FW3_TARGET_DROP)
126 warn_elem(e, "has invalid %s policy, defaulting to DROP", name);
127 *pol = FW3_TARGET_DROP;
132 fw3_load_defaults(struct fw3_state *state, struct uci_package *p)
134 struct uci_section *s;
135 struct uci_element *e;
136 struct fw3_defaults *defs = &state->defaults;
140 defs->syn_flood_rate.rate = 25;
141 defs->syn_flood_rate.burst = 50;
142 defs->tcp_syncookies = true;
143 defs->tcp_window_scaling = true;
144 defs->custom_chains = true;
146 setbit(defs->flags, FW3_FAMILY_V4);
148 uci_foreach_element(&p->sections, e)
150 s = uci_to_section(e);
152 if (strcmp(s->type, "defaults"))
157 warn_elem(e, "ignoring duplicate section");
161 fw3_parse_options(&state->defaults, fw3_default_opts, s);
163 check_policy(e, &defs->policy_input, "input");
164 check_policy(e, &defs->policy_output, "output");
165 check_policy(e, &defs->policy_forward, "forward");
167 if (!defs->disable_ipv6)
168 setbit(defs->flags, FW3_FAMILY_V6);
170 if (defs->custom_chains)
171 setbit(defs->flags, FW3_DEFAULT_CUSTOM_CHAINS);
174 setbit(defs->flags, FW3_DEFAULT_SYN_FLOOD);
179 fw3_print_default_chains(enum fw3_table table, enum fw3_family family,
180 struct fw3_state *state)
182 struct fw3_defaults *defs = &state->defaults;
186 ((t == FW3_TARGET_REJECT) ? "DROP" : fw3_flag_names[t])
188 if (table == FW3_TABLE_FILTER)
190 fw3_pr(":INPUT %s [0:0]\n", policy(defs->policy_input));
191 fw3_pr(":FORWARD %s [0:0]\n", policy(defs->policy_forward));
192 fw3_pr(":OUTPUT %s [0:0]\n", policy(defs->policy_output));
195 /* user chains already loaded, don't create again */
196 if (hasbit(state->running_defaults.flags, FW3_DEFAULT_CUSTOM_CHAINS))
197 delbit(mask, FW3_DEFAULT_CUSTOM_CHAINS);
199 print_chains(table, family, ":%s - [0:0]\n", defs->flags & mask,
200 default_chains, ARRAY_SIZE(default_chains));
204 fw3_print_default_head_rules(enum fw3_table table, enum fw3_family family,
205 struct fw3_state *state)
208 struct fw3_defaults *defs = &state->defaults;
209 const char *chains[] = {
215 print_chains(table, family, "-A %s\n", 0,
216 toplevel_rules, ARRAY_SIZE(toplevel_rules));
220 case FW3_TABLE_FILTER:
221 fw3_pr("-A delegate_input -i lo -j ACCEPT\n");
222 fw3_pr("-A delegate_output -o lo -j ACCEPT\n");
224 if (defs->custom_chains)
226 fw3_pr("-A delegate_input -j input_rule\n");
227 fw3_pr("-A delegate_output -j output_rule\n");
228 fw3_pr("-A delegate_forward -j forwarding_rule\n");
231 for (i = 0; i < ARRAY_SIZE(chains); i++)
233 fw3_pr("-A delegate_%s -m conntrack --ctstate RELATED,ESTABLISHED "
234 "-j ACCEPT\n", chains[i]);
236 if (defs->drop_invalid)
238 fw3_pr("-A delegate_%s -m conntrack --ctstate INVALID -j DROP\n",
245 fw3_pr("-A syn_flood -p tcp --syn");
246 fw3_format_limit(&defs->syn_flood_rate);
247 fw3_pr(" -j RETURN\n");
249 fw3_pr("-A syn_flood -j DROP\n");
250 fw3_pr("-A delegate_input -p tcp --syn -j syn_flood\n");
253 fw3_pr("-A reject -p tcp -j REJECT --reject-with tcp-reset\n");
254 fw3_pr("-A reject -j REJECT --reject-with port-unreach\n");
259 if (defs->custom_chains)
261 fw3_pr("-A delegate_prerouting -j prerouting_rule\n");
262 fw3_pr("-A delegate_postrouting -j postrouting_rule\n");
272 fw3_print_default_tail_rules(enum fw3_table table, enum fw3_family family,
273 struct fw3_state *state)
275 struct fw3_defaults *defs = &state->defaults;
277 if (table != FW3_TABLE_FILTER)
280 if (defs->policy_input == FW3_TARGET_REJECT)
281 fw3_pr("-A delegate_input -j reject\n");
283 if (defs->policy_output == FW3_TARGET_REJECT)
284 fw3_pr("-A delegate_output -j reject\n");
286 if (defs->policy_forward == FW3_TARGET_REJECT)
287 fw3_pr("-A delegate_forward -j reject\n");
291 set_default(const char *name, bool set)
294 char path[sizeof("/proc/sys/net/ipv4/tcp_window_scaling\0")];
296 snprintf(path, sizeof(path), "/proc/sys/net/ipv4/tcp_%s", name);
298 info(" * Set tcp_%s to %s", name, set ? "on" : "off", name);
300 if (!(f = fopen(path, "w")))
302 info(" ! Unable to write value: %s", strerror(errno));
306 fprintf(f, "%u\n", set);
311 fw3_set_defaults(struct fw3_state *state)
313 info("Setting sysctl values");
315 set_default("ecn", state->defaults.tcp_ecn);
316 set_default("syncookies", state->defaults.tcp_syncookies);
317 set_default("window_scaling", state->defaults.tcp_window_scaling);
321 reset_policy(enum fw3_table table, enum fw3_target policy)
323 if (table != FW3_TABLE_FILTER)
326 fw3_pr(":INPUT %s [0:0]\n", fw3_flag_names[policy]);
327 fw3_pr(":OUTPUT %s [0:0]\n", fw3_flag_names[policy]);
328 fw3_pr(":FORWARD %s [0:0]\n", fw3_flag_names[policy]);
332 fw3_flush_rules(enum fw3_table table, enum fw3_family family,
333 bool pass2, struct fw3_state *state, enum fw3_target policy)
335 struct fw3_defaults *d = &state->running_defaults;
338 if (!hasbit(d->flags, family))
341 /* don't touch user chains on selective stop */
342 delbit(mask, FW3_DEFAULT_CUSTOM_CHAINS);
346 reset_policy(table, policy);
348 print_chains(table, family, "-D %s\n", d->flags & mask,
349 toplevel_rules, ARRAY_SIZE(toplevel_rules));
351 print_chains(table, family, "-F %s\n", d->flags & mask,
352 default_chains, ARRAY_SIZE(default_chains));
356 print_chains(table, family, "-X %s\n", d->flags & mask,
357 default_chains, ARRAY_SIZE(default_chains));
359 delbit(d->flags, family);
364 fw3_flush_all(enum fw3_table table)
366 reset_policy(table, FW3_TARGET_ACCEPT);