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
, uint32_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
;
183 uint32_t custom_mask
= ~0;
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
->defaults
.running_flags
, FW3_DEFAULT_CUSTOM_CHAINS
))
197 delbit(custom_mask
, FW3_DEFAULT_CUSTOM_CHAINS
);
199 print_chains(table
, family
, ":%s - [0:0]\n", defs
->flags
& custom_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
[] = {
212 "forward", "forwarding",
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 for (i
= 0; i
< ARRAY_SIZE(chains
); i
+= 2)
228 fw3_pr("-A delegate_%s -m comment "
229 "--comment \"user chain for %s\" -j %s_rule\n",
230 chains
[i
], chains
[i
+1], chains
[i
+1]);
234 for (i
= 0; i
< ARRAY_SIZE(chains
); i
+= 2)
236 fw3_pr("-A delegate_%s -m conntrack --ctstate RELATED,ESTABLISHED "
237 "-j ACCEPT\n", chains
[i
]);
239 if (defs
->drop_invalid
)
241 fw3_pr("-A delegate_%s -m conntrack --ctstate INVALID -j DROP\n",
248 fw3_pr("-A syn_flood -p tcp --syn");
249 fw3_format_limit(&defs
->syn_flood_rate
);
250 fw3_pr(" -j RETURN\n");
252 fw3_pr("-A syn_flood -j DROP\n");
253 fw3_pr("-A delegate_input -p tcp --syn -j syn_flood\n");
256 fw3_pr("-A reject -p tcp -j REJECT --reject-with tcp-reset\n");
257 fw3_pr("-A reject -j REJECT --reject-with port-unreach\n");
262 if (defs
->custom_chains
)
264 fw3_pr("-A delegate_prerouting "
265 "-m comment --comment \"user chain for prerouting\" "
266 "-j prerouting_rule\n");
268 fw3_pr("-A delegate_postrouting "
269 "-m comment --comment \"user chain for postrouting\" "
270 "-j postrouting_rule\n");
280 fw3_print_default_tail_rules(enum fw3_table table
, enum fw3_family family
,
281 struct fw3_state
*state
)
283 struct fw3_defaults
*defs
= &state
->defaults
;
285 if (table
!= FW3_TABLE_FILTER
)
288 if (defs
->policy_input
== FW3_TARGET_REJECT
)
289 fw3_pr("-A delegate_input -j reject\n");
291 if (defs
->policy_output
== FW3_TARGET_REJECT
)
292 fw3_pr("-A delegate_output -j reject\n");
294 if (defs
->policy_forward
== FW3_TARGET_REJECT
)
295 fw3_pr("-A delegate_forward -j reject\n");
299 set_default(const char *name
, bool set
)
302 char path
[sizeof("/proc/sys/net/ipv4/tcp_window_scaling\0")];
304 snprintf(path
, sizeof(path
), "/proc/sys/net/ipv4/tcp_%s", name
);
306 info(" * Set tcp_%s to %s", name
, set
? "on" : "off", name
);
308 if (!(f
= fopen(path
, "w")))
310 info(" ! Unable to write value: %s", strerror(errno
));
314 fprintf(f
, "%u\n", set
);
319 fw3_set_defaults(struct fw3_state
*state
)
321 info("Setting sysctl values");
323 set_default("ecn", state
->defaults
.tcp_ecn
);
324 set_default("syncookies", state
->defaults
.tcp_syncookies
);
325 set_default("window_scaling", state
->defaults
.tcp_window_scaling
);
329 reset_policy(enum fw3_table table
, enum fw3_target policy
)
331 if (table
!= FW3_TABLE_FILTER
)
334 fw3_pr(":INPUT %s [0:0]\n", fw3_flag_names
[policy
]);
335 fw3_pr(":OUTPUT %s [0:0]\n", fw3_flag_names
[policy
]);
336 fw3_pr(":FORWARD %s [0:0]\n", fw3_flag_names
[policy
]);
340 fw3_flush_rules(enum fw3_table table
, enum fw3_family family
,
341 bool pass2
, struct fw3_state
*state
, enum fw3_target policy
)
343 struct fw3_defaults
*defs
= &state
->defaults
;
344 uint32_t custom_mask
= ~0;
346 if (!hasbit(defs
->running_flags
, family
))
349 /* don't touch user chains on selective stop */
350 delbit(custom_mask
, FW3_DEFAULT_CUSTOM_CHAINS
);
354 reset_policy(table
, policy
);
356 print_chains(table
, family
, "-D %s\n",
357 defs
->running_flags
& custom_mask
,
358 toplevel_rules
, ARRAY_SIZE(toplevel_rules
));
360 print_chains(table
, family
, "-F %s\n",
361 defs
->running_flags
& custom_mask
,
362 default_chains
, ARRAY_SIZE(default_chains
));
366 print_chains(table
, family
, "-X %s\n",
367 defs
->running_flags
& custom_mask
,
368 default_chains
, ARRAY_SIZE(default_chains
));
370 delbit(defs
->flags
, family
);
375 fw3_flush_all(enum fw3_table table
)
377 reset_policy(table
, FW3_TARGET_ACCEPT
);