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
);