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Diffstat (limited to 'src/util/tun.c')
-rw-r--r-- | src/util/tun.c | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/src/util/tun.c b/src/util/tun.c new file mode 100644 index 000000000..f85f72209 --- /dev/null +++ b/src/util/tun.c | |||
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1 | /* | ||
2 | This file is part of GNUnet. | ||
3 | Copyright (C) 2010, 2011, 2012 Christian Grothoff | ||
4 | |||
5 | GNUnet is free software: you can redistribute it and/or modify it | ||
6 | under the terms of the GNU Affero General Public License as published | ||
7 | by the Free Software Foundation, either version 3 of the License, | ||
8 | or (at your option) any later version. | ||
9 | |||
10 | GNUnet is distributed in the hope that it will be useful, but | ||
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
13 | Affero General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU Affero General Public License | ||
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
17 | */ | ||
18 | |||
19 | /** | ||
20 | * @file tun/tun.c | ||
21 | * @brief standard IP calculations for TUN interaction | ||
22 | * @author Philipp Toelke | ||
23 | * @author Christian Grothoff | ||
24 | */ | ||
25 | #include "platform.h" | ||
26 | #include "gnunet_tun_lib.h" | ||
27 | |||
28 | /** | ||
29 | * IP TTL we use for packets that we assemble (8 bit unsigned integer) | ||
30 | */ | ||
31 | #define FRESH_TTL 64 | ||
32 | |||
33 | |||
34 | /** | ||
35 | * Initialize an IPv4 header. | ||
36 | * | ||
37 | * @param ip header to initialize | ||
38 | * @param protocol protocol to use (i.e. IPPROTO_UDP) | ||
39 | * @param payload_length number of bytes of payload that follow (excluding IPv4 header) | ||
40 | * @param src source IP address to use | ||
41 | * @param dst destination IP address to use | ||
42 | */ | ||
43 | void | ||
44 | GNUNET_TUN_initialize_ipv4_header (struct GNUNET_TUN_IPv4Header *ip, | ||
45 | uint8_t protocol, | ||
46 | uint16_t payload_length, | ||
47 | const struct in_addr *src, | ||
48 | const struct in_addr *dst) | ||
49 | { | ||
50 | GNUNET_assert (20 == sizeof (struct GNUNET_TUN_IPv4Header)); | ||
51 | GNUNET_assert (payload_length <= UINT16_MAX - sizeof (struct GNUNET_TUN_IPv4Header)); | ||
52 | memset (ip, 0, sizeof (struct GNUNET_TUN_IPv4Header)); | ||
53 | ip->header_length = sizeof (struct GNUNET_TUN_IPv4Header) / 4; | ||
54 | ip->version = 4; | ||
55 | ip->total_length = htons (sizeof (struct GNUNET_TUN_IPv4Header) + payload_length); | ||
56 | ip->identification = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, | ||
57 | 65536); | ||
58 | ip->ttl = FRESH_TTL; | ||
59 | ip->protocol = protocol; | ||
60 | ip->source_address = *src; | ||
61 | ip->destination_address = *dst; | ||
62 | ip->checksum = GNUNET_CRYPTO_crc16_n (ip, sizeof (struct GNUNET_TUN_IPv4Header)); | ||
63 | } | ||
64 | |||
65 | |||
66 | /** | ||
67 | * Initialize an IPv6 header. | ||
68 | * | ||
69 | * @param ip header to initialize | ||
70 | * @param protocol protocol to use (i.e. IPPROTO_UDP), technically "next_header" for IPv6 | ||
71 | * @param payload_length number of bytes of payload that follow (excluding IPv6 header) | ||
72 | * @param src source IP address to use | ||
73 | * @param dst destination IP address to use | ||
74 | */ | ||
75 | void | ||
76 | GNUNET_TUN_initialize_ipv6_header (struct GNUNET_TUN_IPv6Header *ip, | ||
77 | uint8_t protocol, | ||
78 | uint16_t payload_length, | ||
79 | const struct in6_addr *src, | ||
80 | const struct in6_addr *dst) | ||
81 | { | ||
82 | GNUNET_assert (40 == sizeof (struct GNUNET_TUN_IPv6Header)); | ||
83 | GNUNET_assert (payload_length <= UINT16_MAX - sizeof (struct GNUNET_TUN_IPv6Header)); | ||
84 | memset (ip, 0, sizeof (struct GNUNET_TUN_IPv6Header)); | ||
85 | ip->version = 6; | ||
86 | ip->next_header = protocol; | ||
87 | ip->payload_length = htons ((uint16_t) payload_length); | ||
88 | ip->hop_limit = FRESH_TTL; | ||
89 | ip->destination_address = *dst; | ||
90 | ip->source_address = *src; | ||
91 | } | ||
92 | |||
93 | |||
94 | /** | ||
95 | * Calculate IPv4 TCP checksum. | ||
96 | * | ||
97 | * @param ip ipv4 header fully initialized | ||
98 | * @param tcp TCP header (initialized except for CRC) | ||
99 | * @param payload the TCP payload | ||
100 | * @param payload_length number of bytes of TCP payload | ||
101 | */ | ||
102 | void | ||
103 | GNUNET_TUN_calculate_tcp4_checksum (const struct GNUNET_TUN_IPv4Header *ip, | ||
104 | struct GNUNET_TUN_TcpHeader *tcp, | ||
105 | const void *payload, | ||
106 | uint16_t payload_length) | ||
107 | { | ||
108 | uint32_t sum; | ||
109 | uint16_t tmp; | ||
110 | |||
111 | GNUNET_assert (20 == sizeof (struct GNUNET_TUN_TcpHeader)); | ||
112 | GNUNET_assert (payload_length + sizeof (struct GNUNET_TUN_IPv4Header) + sizeof (struct GNUNET_TUN_TcpHeader) == | ||
113 | ntohs (ip->total_length)); | ||
114 | GNUNET_assert (IPPROTO_TCP == ip->protocol); | ||
115 | |||
116 | tcp->crc = 0; | ||
117 | sum = GNUNET_CRYPTO_crc16_step (0, | ||
118 | &ip->source_address, | ||
119 | sizeof (struct in_addr) * 2); | ||
120 | tmp = htons (IPPROTO_TCP); | ||
121 | sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint16_t)); | ||
122 | tmp = htons (payload_length + sizeof (struct GNUNET_TUN_TcpHeader)); | ||
123 | sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint16_t)); | ||
124 | sum = GNUNET_CRYPTO_crc16_step (sum, tcp, sizeof (struct GNUNET_TUN_TcpHeader)); | ||
125 | sum = GNUNET_CRYPTO_crc16_step (sum, payload, payload_length); | ||
126 | tcp->crc = GNUNET_CRYPTO_crc16_finish (sum); | ||
127 | } | ||
128 | |||
129 | |||
130 | /** | ||
131 | * Calculate IPv6 TCP checksum. | ||
132 | * | ||
133 | * @param ip ipv6 header fully initialized | ||
134 | * @param tcp header (initialized except for CRC) | ||
135 | * @param payload the TCP payload | ||
136 | * @param payload_length number of bytes of TCP payload | ||
137 | */ | ||
138 | void | ||
139 | GNUNET_TUN_calculate_tcp6_checksum (const struct GNUNET_TUN_IPv6Header *ip, | ||
140 | struct GNUNET_TUN_TcpHeader *tcp, | ||
141 | const void *payload, | ||
142 | uint16_t payload_length) | ||
143 | { | ||
144 | uint32_t sum; | ||
145 | uint32_t tmp; | ||
146 | |||
147 | GNUNET_assert (20 == sizeof (struct GNUNET_TUN_TcpHeader)); | ||
148 | GNUNET_assert (payload_length + sizeof (struct GNUNET_TUN_TcpHeader) == | ||
149 | ntohs (ip->payload_length)); | ||
150 | GNUNET_assert (IPPROTO_TCP == ip->next_header); | ||
151 | tcp->crc = 0; | ||
152 | sum = GNUNET_CRYPTO_crc16_step (0, &ip->source_address, 2 * sizeof (struct in6_addr)); | ||
153 | tmp = htonl (sizeof (struct GNUNET_TUN_TcpHeader) + payload_length); | ||
154 | sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint32_t)); | ||
155 | tmp = htonl (IPPROTO_TCP); | ||
156 | sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint32_t)); | ||
157 | sum = GNUNET_CRYPTO_crc16_step (sum, tcp, | ||
158 | sizeof (struct GNUNET_TUN_TcpHeader)); | ||
159 | sum = GNUNET_CRYPTO_crc16_step (sum, payload, payload_length); | ||
160 | tcp->crc = GNUNET_CRYPTO_crc16_finish (sum); | ||
161 | } | ||
162 | |||
163 | |||
164 | /** | ||
165 | * Calculate IPv4 UDP checksum. | ||
166 | * | ||
167 | * @param ip ipv4 header fully initialized | ||
168 | * @param udp UDP header (initialized except for CRC) | ||
169 | * @param payload the UDP payload | ||
170 | * @param payload_length number of bytes of UDP payload | ||
171 | */ | ||
172 | void | ||
173 | GNUNET_TUN_calculate_udp4_checksum (const struct GNUNET_TUN_IPv4Header *ip, | ||
174 | struct GNUNET_TUN_UdpHeader *udp, | ||
175 | const void *payload, | ||
176 | uint16_t payload_length) | ||
177 | { | ||
178 | uint32_t sum; | ||
179 | uint16_t tmp; | ||
180 | |||
181 | GNUNET_assert (8 == sizeof (struct GNUNET_TUN_UdpHeader)); | ||
182 | GNUNET_assert (payload_length + sizeof (struct GNUNET_TUN_IPv4Header) + sizeof (struct GNUNET_TUN_UdpHeader) == | ||
183 | ntohs (ip->total_length)); | ||
184 | GNUNET_assert (IPPROTO_UDP == ip->protocol); | ||
185 | |||
186 | udp->crc = 0; /* technically optional, but we calculate it anyway, just to be sure */ | ||
187 | sum = GNUNET_CRYPTO_crc16_step (0, | ||
188 | &ip->source_address, | ||
189 | sizeof (struct in_addr) * 2); | ||
190 | tmp = htons (IPPROTO_UDP); | ||
191 | sum = GNUNET_CRYPTO_crc16_step (sum, | ||
192 | &tmp, | ||
193 | sizeof (uint16_t)); | ||
194 | tmp = htons (sizeof (struct GNUNET_TUN_UdpHeader) + payload_length); | ||
195 | sum = GNUNET_CRYPTO_crc16_step (sum, | ||
196 | &tmp, | ||
197 | sizeof (uint16_t)); | ||
198 | sum = GNUNET_CRYPTO_crc16_step (sum, | ||
199 | udp, | ||
200 | sizeof (struct GNUNET_TUN_UdpHeader)); | ||
201 | sum = GNUNET_CRYPTO_crc16_step (sum, | ||
202 | payload, | ||
203 | payload_length); | ||
204 | udp->crc = GNUNET_CRYPTO_crc16_finish (sum); | ||
205 | } | ||
206 | |||
207 | |||
208 | /** | ||
209 | * Calculate IPv6 UDP checksum. | ||
210 | * | ||
211 | * @param ip ipv6 header fully initialized | ||
212 | * @param udp UDP header (initialized except for CRC) | ||
213 | * @param payload the UDP payload | ||
214 | * @param payload_length number of bytes of UDP payload | ||
215 | */ | ||
216 | void | ||
217 | GNUNET_TUN_calculate_udp6_checksum (const struct GNUNET_TUN_IPv6Header *ip, | ||
218 | struct GNUNET_TUN_UdpHeader *udp, | ||
219 | const void *payload, | ||
220 | uint16_t payload_length) | ||
221 | { | ||
222 | uint32_t sum; | ||
223 | uint32_t tmp; | ||
224 | |||
225 | GNUNET_assert (payload_length + sizeof (struct GNUNET_TUN_UdpHeader) == | ||
226 | ntohs (ip->payload_length)); | ||
227 | GNUNET_assert (payload_length + sizeof (struct GNUNET_TUN_UdpHeader) == | ||
228 | ntohs (udp->len)); | ||
229 | GNUNET_assert (IPPROTO_UDP == ip->next_header); | ||
230 | |||
231 | udp->crc = 0; | ||
232 | sum = GNUNET_CRYPTO_crc16_step (0, | ||
233 | &ip->source_address, | ||
234 | sizeof (struct in6_addr) * 2); | ||
235 | tmp = htons (sizeof (struct GNUNET_TUN_UdpHeader) + payload_length); /* aka udp->len */ | ||
236 | sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint32_t)); | ||
237 | tmp = htons (ip->next_header); | ||
238 | sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint32_t)); | ||
239 | sum = GNUNET_CRYPTO_crc16_step (sum, udp, sizeof (struct GNUNET_TUN_UdpHeader)); | ||
240 | sum = GNUNET_CRYPTO_crc16_step (sum, payload, payload_length); | ||
241 | udp->crc = GNUNET_CRYPTO_crc16_finish (sum); | ||
242 | } | ||
243 | |||
244 | |||
245 | /** | ||
246 | * Calculate ICMP checksum. | ||
247 | * | ||
248 | * @param icmp IMCP header (initialized except for CRC) | ||
249 | * @param payload the ICMP payload | ||
250 | * @param payload_length number of bytes of ICMP payload | ||
251 | */ | ||
252 | void | ||
253 | GNUNET_TUN_calculate_icmp_checksum (struct GNUNET_TUN_IcmpHeader *icmp, | ||
254 | const void *payload, | ||
255 | uint16_t payload_length) | ||
256 | { | ||
257 | uint32_t sum; | ||
258 | |||
259 | GNUNET_assert (8 == sizeof (struct GNUNET_TUN_IcmpHeader)); | ||
260 | icmp->crc = 0; | ||
261 | sum = GNUNET_CRYPTO_crc16_step (0, | ||
262 | icmp, | ||
263 | sizeof (struct GNUNET_TUN_IcmpHeader)); | ||
264 | sum = GNUNET_CRYPTO_crc16_step (sum, payload, payload_length); | ||
265 | icmp->crc = GNUNET_CRYPTO_crc16_finish (sum); | ||
266 | } | ||
267 | |||
268 | |||
269 | /** | ||
270 | * Check if two sockaddrs are equal. | ||
271 | * | ||
272 | * @param sa one address | ||
273 | * @param sb another address | ||
274 | * @param include_port also check ports | ||
275 | * @return #GNUNET_YES if they are equal | ||
276 | */ | ||
277 | int | ||
278 | GNUNET_TUN_sockaddr_cmp (const struct sockaddr *sa, | ||
279 | const struct sockaddr *sb, | ||
280 | int include_port) | ||
281 | { | ||
282 | if (sa->sa_family != sb->sa_family) | ||
283 | return GNUNET_NO; | ||
284 | |||
285 | switch (sa->sa_family) | ||
286 | { | ||
287 | case AF_INET: | ||
288 | { | ||
289 | const struct sockaddr_in *sa4 = (const struct sockaddr_in *) sa; | ||
290 | const struct sockaddr_in *sb4 = (const struct sockaddr_in *) sb; | ||
291 | return (sa4->sin_addr.s_addr == sb4->sin_addr.s_addr); | ||
292 | } | ||
293 | case AF_INET6: | ||
294 | { | ||
295 | const struct sockaddr_in6 *sa6 = (const struct sockaddr_in6 *) sa; | ||
296 | const struct sockaddr_in6 *sb6 = (const struct sockaddr_in6 *) sb; | ||
297 | |||
298 | return (0 == memcmp(&sa6->sin6_addr, | ||
299 | &sb6->sin6_addr, | ||
300 | sizeof (struct in6_addr))); | ||
301 | } | ||
302 | default: | ||
303 | GNUNET_break (0); | ||
304 | return GNUNET_SYSERR; | ||
305 | } | ||
306 | } | ||
307 | |||
308 | |||
309 | /* end of tun.c */ | ||