1 /*
2 * Copyright 2011 Daniel Drown
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *
16 * clatd.h - main routines used by clatd
17 */
18 #ifndef __CLATD_H__
19 #define __CLATD_H__
20
21 #include <signal.h>
22 #include <stdlib.h>
23 #include <sys/uio.h>
24
25 struct tun_data;
26
27 // IPv4 header has a u16 total length field, for maximum L3 mtu of 0xFFFF.
28 //
29 // Translating IPv4 to IPv6 requires removing the IPv4 header (20) and adding
30 // an IPv6 header (40), possibly with an extra ipv6 fragment extension header (8).
31 //
32 // As such the maximum IPv4 L3 mtu size is 0xFFFF (by u16 tot_len field)
33 // and the maximum IPv6 L3 mtu size is 0xFFFF + 28 (which is larger)
34 //
35 // A received non-jumbogram IPv6 frame could potentially be u16 payload_len = 0xFFFF
36 // + sizeof ipv6 header = 40, bytes in size. But such a packet cannot be meaningfully
37 // converted to IPv4 (it's too large). As such the restriction is the same: 0xFFFF + 28
38 //
39 // (since there's no jumbogram support in IPv4, IPv6 jumbograms cannot be meaningfully
40 // converted to IPv4 anyway, and are thus entirely unsupported)
41 #define MAXMTU (0xFFFF + 28)
42
43 // logcat_hexdump() maximum binary data length, this is the maximum packet size
44 // plus some extra space for various headers:
45 // struct tun_pi (4 bytes)
46 // struct virtio_net_hdr (10 bytes)
47 // ethernet (14 bytes), potentially including vlan tag (4) or tags (8 or 12)
48 // plus some extra just-in-case headroom, because it doesn't hurt.
49 #define MAXDUMPLEN (64 + MAXMTU)
50
51 #define CLATD_VERSION "1.7"
52
53 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
54
55 extern volatile sig_atomic_t running;
56
57 void event_loop(struct tun_data *tunnel);
58
59 /* function: parse_int
60 * parses a string as a decimal/hex/octal signed integer
61 * str - the string to parse
62 * out - the signed integer to write to, gets clobbered on failure
63 */
parse_int(const char * str,int * out)64 static inline int parse_int(const char *str, int *out) {
65 char *end_ptr;
66 *out = strtol(str, &end_ptr, 0);
67 return *str && !*end_ptr;
68 }
69
70 /* function: parse_unsigned
71 * parses a string as a decimal/hex/octal unsigned integer
72 * str - the string to parse
73 * out - the unsigned integer to write to, gets clobbered on failure
74 */
parse_unsigned(const char * str,unsigned * out)75 static inline int parse_unsigned(const char *str, unsigned *out) {
76 char *end_ptr;
77 *out = strtoul(str, &end_ptr, 0);
78 return *str && !*end_ptr;
79 }
80
81 #endif /* __CLATD_H__ */
82