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_rule_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, "notrack"),
48 static const struct fw3_rule_spec toplevel_rules[] = {
49 C(ANY, FILTER, UNSPEC, "INPUT -j delegate_input"),
50 C(ANY, FILTER, UNSPEC, "OUTPUT -j delegate_output"),
51 C(ANY, FILTER, UNSPEC, "FORWARD -j delegate_forward"),
53 C(V4, NAT, UNSPEC, "PREROUTING -j delegate_prerouting"),
54 C(V4, NAT, UNSPEC, "POSTROUTING -j delegate_postrouting"),
56 C(ANY, MANGLE, UNSPEC, "FORWARD -j mssfix"),
57 C(ANY, MANGLE, UNSPEC, "PREROUTING -j fwmark"),
59 C(ANY, RAW, UNSPEC, "PREROUTING -j notrack"),
64 const struct fw3_option fw3_flag_opts[] = {
65 FW3_OPT("input", target, defaults, policy_input),
66 FW3_OPT("forward", target, defaults, policy_forward),
67 FW3_OPT("output", target, defaults, policy_output),
69 FW3_OPT("drop_invalid", bool, defaults, drop_invalid),
71 FW3_OPT("syn_flood", bool, defaults, syn_flood),
72 FW3_OPT("synflood_protect", bool, defaults, syn_flood),
73 FW3_OPT("synflood_rate", limit, defaults, syn_flood_rate),
74 FW3_OPT("synflood_burst", int, defaults, syn_flood_rate.burst),
76 FW3_OPT("tcp_syncookies", bool, defaults, tcp_syncookies),
77 FW3_OPT("tcp_ecn", bool, defaults, tcp_ecn),
78 FW3_OPT("tcp_window_scaling", bool, defaults, tcp_window_scaling),
80 FW3_OPT("accept_redirects", bool, defaults, accept_redirects),
81 FW3_OPT("accept_source_route", bool, defaults, accept_source_route),
83 FW3_OPT("custom_chains", bool, defaults, custom_chains),
84 FW3_OPT("disable_ipv6", bool, defaults, disable_ipv6),
86 FW3_OPT("__flags_v4", int, defaults, flags[0]),
87 FW3_OPT("__flags_v6", int, defaults, flags[1]),
94 check_policy(struct uci_element *e, enum fw3_flag *pol, const char *name)
96 if (*pol == FW3_FLAG_UNSPEC)
98 warn_elem(e, "has no %s policy specified, defaulting to DROP", name);
101 else if (*pol > FW3_FLAG_DROP)
103 warn_elem(e, "has invalid %s policy, defaulting to DROP", name);
104 *pol = FW3_FLAG_DROP;
109 fw3_load_defaults(struct fw3_state *state, struct uci_package *p)
111 struct uci_section *s;
112 struct uci_element *e;
113 struct fw3_defaults *defs = &state->defaults;
117 defs->syn_flood_rate.rate = 25;
118 defs->syn_flood_rate.burst = 50;
119 defs->tcp_syncookies = true;
120 defs->tcp_window_scaling = true;
121 defs->custom_chains = true;
123 uci_foreach_element(&p->sections, e)
125 s = uci_to_section(e);
127 if (strcmp(s->type, "defaults"))
132 warn_elem(e, "ignoring duplicate section");
136 fw3_parse_options(&state->defaults, fw3_flag_opts, s);
138 check_policy(e, &defs->policy_input, "input");
139 check_policy(e, &defs->policy_output, "output");
140 check_policy(e, &defs->policy_forward, "forward");
145 fw3_print_default_chains(struct fw3_state *state, enum fw3_family family,
146 enum fw3_table table, bool reload)
149 struct fw3_defaults *defs = &state->defaults;
150 uint32_t custom_mask = ~0;
153 ((t == FW3_FLAG_REJECT) ? "DROP" : fw3_flag_names[t])
155 if (family == FW3_FAMILY_V6 && defs->disable_ipv6)
158 if (table == FW3_TABLE_FILTER)
160 fw3_pr(":INPUT %s [0:0]\n", policy(defs->policy_input));
161 fw3_pr(":FORWARD %s [0:0]\n", policy(defs->policy_forward));
162 fw3_pr(":OUTPUT %s [0:0]\n", policy(defs->policy_output));
165 /* Don't touch user chains on reload */
167 delbit(custom_mask, FW3_FLAG_CUSTOM_CHAINS);
169 if (defs->custom_chains)
170 set(defs->flags, family, FW3_FLAG_CUSTOM_CHAINS);
173 set(defs->flags, family, FW3_FLAG_SYN_FLOOD);
175 rv = fw3_pr_rulespec(table, family, defs->flags, custom_mask,
176 default_chains, ":%s - [0:0]\n");
179 set(defs->flags, family, table);
183 fw3_print_default_head_rules(struct fw3_state *state, enum fw3_family family,
184 enum fw3_table table, bool reload)
187 struct fw3_defaults *defs = &state->defaults;
188 const char *chains[] = {
191 "forward", "forwarding",
194 fw3_pr_rulespec(table, family, NULL, 0, toplevel_rules, "-A %s\n");
198 case FW3_TABLE_FILTER:
199 fw3_pr("-A delegate_input -i lo -j ACCEPT\n");
200 fw3_pr("-A delegate_output -o lo -j ACCEPT\n");
202 if (defs->custom_chains)
204 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
206 fw3_pr("-A delegate_%s -m comment "
207 "--comment \"user chain for %s\" -j %s_rule\n",
208 chains[i], chains[i+1], chains[i+1]);
212 for (i = 0; i < ARRAY_SIZE(chains); i += 2)
214 fw3_pr("-A delegate_%s -m conntrack --ctstate RELATED,ESTABLISHED "
215 "-j ACCEPT\n", chains[i]);
217 if (defs->drop_invalid)
219 fw3_pr("-A delegate_%s -m conntrack --ctstate INVALID -j DROP\n",
226 fw3_pr("-A syn_flood -p tcp --syn");
227 fw3_format_limit(&defs->syn_flood_rate);
228 fw3_pr(" -j RETURN\n");
230 fw3_pr("-A syn_flood -j DROP\n");
231 fw3_pr("-A delegate_input -p tcp --syn -j syn_flood\n");
234 fw3_pr("-A reject -p tcp -j REJECT --reject-with tcp-reset\n");
235 fw3_pr("-A reject -j REJECT --reject-with port-unreach\n");
240 if (defs->custom_chains)
242 fw3_pr("-A delegate_prerouting "
243 "-m comment --comment \"user chain for prerouting\" "
244 "-j prerouting_rule\n");
246 fw3_pr("-A delegate_postrouting "
247 "-m comment --comment \"user chain for postrouting\" "
248 "-j postrouting_rule\n");
258 fw3_print_default_tail_rules(struct fw3_state *state, enum fw3_family family,
259 enum fw3_table table, bool reload)
261 struct fw3_defaults *defs = &state->defaults;
263 if (table != FW3_TABLE_FILTER)
266 if (defs->policy_input == FW3_FLAG_REJECT)
267 fw3_pr("-A delegate_input -j reject\n");
269 if (defs->policy_output == FW3_FLAG_REJECT)
270 fw3_pr("-A delegate_output -j reject\n");
272 if (defs->policy_forward == FW3_FLAG_REJECT)
273 fw3_pr("-A delegate_forward -j reject\n");
277 set_default(const char *name, bool set)
280 char path[sizeof("/proc/sys/net/ipv4/tcp_window_scaling\0")];
282 snprintf(path, sizeof(path), "/proc/sys/net/ipv4/tcp_%s", name);
284 info(" * Set tcp_%s to %s", name, set ? "on" : "off", name);
286 if (!(f = fopen(path, "w")))
288 info(" ! Unable to write value: %s", strerror(errno));
292 fprintf(f, "%u\n", set);
297 fw3_set_defaults(struct fw3_state *state)
299 set_default("ecn", state->defaults.tcp_ecn);
300 set_default("syncookies", state->defaults.tcp_syncookies);
301 set_default("window_scaling", state->defaults.tcp_window_scaling);
305 reset_policy(enum fw3_table table, enum fw3_flag policy)
307 if (table != FW3_TABLE_FILTER)
310 fw3_pr(":INPUT %s [0:0]\n", fw3_flag_names[policy]);
311 fw3_pr(":OUTPUT %s [0:0]\n", fw3_flag_names[policy]);
312 fw3_pr(":FORWARD %s [0:0]\n", fw3_flag_names[policy]);
316 fw3_flush_rules(struct fw3_state *state, enum fw3_family family,
317 enum fw3_table table, bool reload, bool pass2)
319 struct fw3_defaults *defs = &state->defaults;
320 uint32_t custom_mask = ~0;
322 if (!has(defs->flags, family, table))
325 /* don't touch user chains on selective stop */
327 delbit(custom_mask, FW3_FLAG_CUSTOM_CHAINS);
331 reset_policy(table, reload ? FW3_FLAG_DROP : FW3_FLAG_ACCEPT);
333 fw3_pr_rulespec(table, family, defs->flags, custom_mask,
334 toplevel_rules, "-D %s\n");
336 fw3_pr_rulespec(table, family, defs->flags, custom_mask,
337 default_chains, "-F %s\n");
341 fw3_pr_rulespec(table, family, defs->flags, custom_mask,
342 default_chains, "-X %s\n");
344 del(defs->flags, family, table);
349 fw3_flush_all(enum fw3_table table)
351 reset_policy(table, FW3_FLAG_ACCEPT);