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064af421 | 1 | /* |
f9ef2270 | 2 | * Copyright (c) 2009, 2010, 2012, 2013, 2014, 2015 Nicira, Inc. |
064af421 | 3 | * |
a14bc59f BP |
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: | |
064af421 | 7 | * |
a14bc59f BP |
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. | |
064af421 BP |
15 | */ |
16 | ||
17 | #include <config.h> | |
2c78a3e6 | 18 | #include "pcap-file.h" |
064af421 BP |
19 | #include <errno.h> |
20 | #include <inttypes.h> | |
b6cdfbb4 | 21 | #include <stdlib.h> |
064af421 | 22 | #include <string.h> |
b6cdfbb4 | 23 | #include <sys/stat.h> |
4cf5406b | 24 | #include "byte-order.h" |
064af421 | 25 | #include "compiler.h" |
cf62fa4c | 26 | #include "dp-packet.h" |
f3dd1419 | 27 | #include "flow.h" |
ee89ea7b | 28 | #include "openvswitch/hmap.h" |
f3dd1419 | 29 | #include "packets.h" |
a797eab3 | 30 | #include "timeval.h" |
f3dd1419 | 31 | #include "unaligned.h" |
ee89ea7b | 32 | #include "util.h" |
e6211adc | 33 | #include "openvswitch/vlog.h" |
064af421 | 34 | |
d98e6007 | 35 | VLOG_DEFINE_THIS_MODULE(pcap); |
5136ce49 | 36 | |
064af421 BP |
37 | struct pcap_hdr { |
38 | uint32_t magic_number; /* magic number */ | |
39 | uint16_t version_major; /* major version number */ | |
40 | uint16_t version_minor; /* minor version number */ | |
41 | int32_t thiszone; /* GMT to local correction */ | |
42 | uint32_t sigfigs; /* accuracy of timestamps */ | |
43 | uint32_t snaplen; /* max length of captured packets */ | |
44 | uint32_t network; /* data link type */ | |
381328fe BP |
45 | }; |
46 | BUILD_ASSERT_DECL(sizeof(struct pcap_hdr) == 24); | |
064af421 BP |
47 | |
48 | struct pcaprec_hdr { | |
49 | uint32_t ts_sec; /* timestamp seconds */ | |
50 | uint32_t ts_usec; /* timestamp microseconds */ | |
51 | uint32_t incl_len; /* number of octets of packet saved in file */ | |
52 | uint32_t orig_len; /* actual length of packet */ | |
381328fe BP |
53 | }; |
54 | BUILD_ASSERT_DECL(sizeof(struct pcaprec_hdr) == 16); | |
064af421 BP |
55 | |
56 | FILE * | |
50aa0364 | 57 | ovs_pcap_open(const char *file_name, const char *mode) |
064af421 | 58 | { |
b6cdfbb4 | 59 | struct stat s; |
064af421 | 60 | FILE *file; |
b6cdfbb4 | 61 | int error; |
064af421 | 62 | |
b6cdfbb4 BP |
63 | ovs_assert(!strcmp(mode, "rb") || |
64 | !strcmp(mode, "wb") || | |
65 | !strcmp(mode, "ab")); | |
064af421 BP |
66 | |
67 | file = fopen(file_name, mode); | |
68 | if (file == NULL) { | |
b6cdfbb4 BP |
69 | VLOG_WARN("%s: failed to open pcap file for %s (%s)", file_name, |
70 | (mode[0] == 'r' ? "reading" | |
71 | : mode[0] == 'w' ? "writing" | |
72 | : "appending"), | |
73 | ovs_strerror(errno)); | |
064af421 BP |
74 | return NULL; |
75 | } | |
76 | ||
b6cdfbb4 BP |
77 | switch (mode[0]) { |
78 | case 'r': | |
50aa0364 | 79 | error = ovs_pcap_read_header(file); |
b6cdfbb4 BP |
80 | if (error) { |
81 | errno = error; | |
064af421 BP |
82 | fclose(file); |
83 | return NULL; | |
84 | } | |
b6cdfbb4 BP |
85 | break; |
86 | ||
87 | case 'w': | |
50aa0364 | 88 | ovs_pcap_write_header(file); |
b6cdfbb4 BP |
89 | break; |
90 | ||
91 | case 'a': | |
92 | if (!fstat(fileno(file), &s) && !s.st_size) { | |
50aa0364 | 93 | ovs_pcap_write_header(file); |
b6cdfbb4 BP |
94 | } |
95 | break; | |
96 | ||
97 | default: | |
428b2edd | 98 | OVS_NOT_REACHED(); |
064af421 BP |
99 | } |
100 | return file; | |
101 | } | |
102 | ||
103 | int | |
50aa0364 | 104 | ovs_pcap_read_header(FILE *file) |
064af421 BP |
105 | { |
106 | struct pcap_hdr ph; | |
107 | if (fread(&ph, sizeof ph, 1, file) != 1) { | |
108 | int error = ferror(file) ? errno : EOF; | |
c18ea70d | 109 | VLOG_WARN("failed to read pcap header: %s", ovs_retval_to_string(error)); |
064af421 BP |
110 | return error; |
111 | } | |
112 | if (ph.magic_number != 0xa1b2c3d4 && ph.magic_number != 0xd4c3b2a1) { | |
113 | VLOG_WARN("bad magic 0x%08"PRIx32" reading pcap file " | |
114 | "(expected 0xa1b2c3d4 or 0xd4c3b2a1)", ph.magic_number); | |
115 | return EPROTO; | |
116 | } | |
117 | return 0; | |
118 | } | |
119 | ||
120 | void | |
50aa0364 | 121 | ovs_pcap_write_header(FILE *file) |
064af421 BP |
122 | { |
123 | /* The pcap reader is responsible for figuring out endianness based on the | |
124 | * magic number, so the lack of htonX calls here is intentional. */ | |
125 | struct pcap_hdr ph; | |
126 | ph.magic_number = 0xa1b2c3d4; | |
127 | ph.version_major = 2; | |
128 | ph.version_minor = 4; | |
129 | ph.thiszone = 0; | |
130 | ph.sigfigs = 0; | |
131 | ph.snaplen = 1518; | |
132 | ph.network = 1; /* Ethernet */ | |
b1b5cd8e | 133 | ignore(fwrite(&ph, sizeof ph, 1, file)); |
f9ef2270 | 134 | fflush(file); |
064af421 BP |
135 | } |
136 | ||
137 | int | |
cf62fa4c | 138 | ovs_pcap_read(FILE *file, struct dp_packet **bufp, long long int *when) |
064af421 BP |
139 | { |
140 | struct pcaprec_hdr prh; | |
cf62fa4c | 141 | struct dp_packet *buf; |
064af421 BP |
142 | void *data; |
143 | size_t len; | |
a797eab3 | 144 | bool swap; |
064af421 BP |
145 | |
146 | *bufp = NULL; | |
147 | ||
148 | /* Read header. */ | |
149 | if (fread(&prh, sizeof prh, 1, file) != 1) { | |
f6cdbd3e BP |
150 | if (ferror(file)) { |
151 | int error = errno; | |
152 | VLOG_WARN("failed to read pcap record header: %s", | |
153 | ovs_retval_to_string(error)); | |
154 | return error; | |
155 | } else { | |
156 | return EOF; | |
157 | } | |
064af421 BP |
158 | } |
159 | ||
160 | /* Calculate length. */ | |
161 | len = prh.incl_len; | |
a797eab3 BP |
162 | swap = len > 0xffff; |
163 | if (swap) { | |
164 | len = uint32_byteswap(len); | |
165 | if (len > 0xffff) { | |
166 | VLOG_WARN("bad packet length %"PRIuSIZE" or %"PRIu32 | |
064af421 | 167 | "reading pcap file", |
a797eab3 | 168 | len, uint32_byteswap(len)); |
064af421 BP |
169 | return EPROTO; |
170 | } | |
a797eab3 BP |
171 | } |
172 | ||
173 | /* Calculate time. */ | |
174 | if (when) { | |
175 | uint32_t ts_sec = swap ? uint32_byteswap(prh.ts_sec) : prh.ts_sec; | |
176 | uint32_t ts_usec = swap ? uint32_byteswap(prh.ts_usec) : prh.ts_usec; | |
177 | *when = ts_sec * 1000LL + ts_usec / 1000; | |
064af421 BP |
178 | } |
179 | ||
180 | /* Read packet. */ | |
cf62fa4c PS |
181 | buf = dp_packet_new(len); |
182 | data = dp_packet_put_uninit(buf, len); | |
064af421 BP |
183 | if (fread(data, len, 1, file) != 1) { |
184 | int error = ferror(file) ? errno : EOF; | |
185 | VLOG_WARN("failed to read pcap packet: %s", | |
c18ea70d | 186 | ovs_retval_to_string(error)); |
cf62fa4c | 187 | dp_packet_delete(buf); |
064af421 BP |
188 | return error; |
189 | } | |
190 | *bufp = buf; | |
191 | return 0; | |
192 | } | |
193 | ||
194 | void | |
cf62fa4c | 195 | ovs_pcap_write(FILE *file, struct dp_packet *buf) |
064af421 BP |
196 | { |
197 | struct pcaprec_hdr prh; | |
a797eab3 BP |
198 | struct timeval tv; |
199 | ||
200 | xgettimeofday(&tv); | |
201 | prh.ts_sec = tv.tv_sec; | |
202 | prh.ts_usec = tv.tv_usec; | |
cf62fa4c PS |
203 | prh.incl_len = dp_packet_size(buf); |
204 | prh.orig_len = dp_packet_size(buf); | |
b1b5cd8e | 205 | ignore(fwrite(&prh, sizeof prh, 1, file)); |
cf62fa4c | 206 | ignore(fwrite(dp_packet_data(buf), dp_packet_size(buf), 1, file)); |
f9ef2270 | 207 | fflush(file); |
064af421 | 208 | } |
f3dd1419 BP |
209 | \f |
210 | struct tcp_key { | |
211 | ovs_be32 nw_src, nw_dst; | |
212 | ovs_be16 tp_src, tp_dst; | |
213 | }; | |
214 | ||
215 | struct tcp_stream { | |
216 | struct hmap_node hmap_node; | |
217 | struct tcp_key key; | |
218 | uint32_t seq_no; | |
cf62fa4c | 219 | struct dp_packet payload; |
f3dd1419 BP |
220 | }; |
221 | ||
222 | struct tcp_reader { | |
223 | struct hmap streams; | |
224 | }; | |
225 | ||
226 | static void | |
227 | tcp_stream_destroy(struct tcp_reader *r, struct tcp_stream *stream) | |
228 | { | |
229 | hmap_remove(&r->streams, &stream->hmap_node); | |
cf62fa4c | 230 | dp_packet_uninit(&stream->payload); |
f3dd1419 BP |
231 | free(stream); |
232 | } | |
233 | ||
234 | /* Returns a new data structure for extracting TCP stream data from an | |
235 | * Ethernet packet capture */ | |
236 | struct tcp_reader * | |
237 | tcp_reader_open(void) | |
238 | { | |
239 | struct tcp_reader *r; | |
240 | ||
241 | r = xmalloc(sizeof *r); | |
242 | hmap_init(&r->streams); | |
243 | return r; | |
244 | } | |
245 | ||
246 | /* Closes and frees 'r'. */ | |
247 | void | |
248 | tcp_reader_close(struct tcp_reader *r) | |
249 | { | |
250 | struct tcp_stream *stream, *next_stream; | |
251 | ||
252 | HMAP_FOR_EACH_SAFE (stream, next_stream, hmap_node, &r->streams) { | |
253 | tcp_stream_destroy(r, stream); | |
254 | } | |
255 | hmap_destroy(&r->streams); | |
256 | free(r); | |
257 | } | |
258 | ||
259 | static struct tcp_stream * | |
276e2864 BP |
260 | tcp_stream_lookup(struct tcp_reader *r, |
261 | const struct tcp_key *key, uint32_t hash) | |
f3dd1419 BP |
262 | { |
263 | struct tcp_stream *stream; | |
f3dd1419 BP |
264 | |
265 | HMAP_FOR_EACH_WITH_HASH (stream, hmap_node, hash, &r->streams) { | |
276e2864 | 266 | if (!memcmp(&stream->key, key, sizeof *key)) { |
f3dd1419 BP |
267 | return stream; |
268 | } | |
269 | } | |
276e2864 BP |
270 | return NULL; |
271 | } | |
272 | ||
273 | static struct tcp_stream * | |
274 | tcp_stream_new(struct tcp_reader *r, const struct tcp_key *key, uint32_t hash) | |
275 | { | |
276 | struct tcp_stream *stream; | |
f3dd1419 BP |
277 | |
278 | stream = xmalloc(sizeof *stream); | |
279 | hmap_insert(&r->streams, &stream->hmap_node, hash); | |
276e2864 | 280 | memcpy(&stream->key, key, sizeof *key); |
f3dd1419 | 281 | stream->seq_no = 0; |
cf62fa4c | 282 | dp_packet_init(&stream->payload, 2048); |
f3dd1419 BP |
283 | return stream; |
284 | } | |
285 | ||
286 | /* Processes 'packet' through TCP reader 'r'. The caller must have already | |
287 | * extracted the packet's headers into 'flow', using flow_extract(). | |
288 | * | |
289 | * If 'packet' is a TCP packet, then the reader attempts to reconstruct the | |
cf62fa4c PS |
290 | * data stream. If successful, it returns an dp_packet that represents the data |
291 | * stream so far. The caller may examine the data in the dp_packet and pull off | |
f3dd1419 BP |
292 | * any data that it has fully processed. The remaining data that the caller |
293 | * does not pull off will be presented again in future calls if more data | |
294 | * arrives in the stream. | |
295 | * | |
296 | * Returns null if 'packet' doesn't add new data to a TCP stream. */ | |
cf62fa4c | 297 | struct dp_packet * |
f3dd1419 | 298 | tcp_reader_run(struct tcp_reader *r, const struct flow *flow, |
cf62fa4c | 299 | const struct dp_packet *packet) |
f3dd1419 BP |
300 | { |
301 | struct tcp_stream *stream; | |
302 | struct tcp_header *tcp; | |
cf62fa4c | 303 | struct dp_packet *payload; |
276e2864 BP |
304 | unsigned int l7_length; |
305 | struct tcp_key key; | |
306 | uint32_t hash; | |
f3dd1419 BP |
307 | uint32_t seq; |
308 | uint8_t flags; | |
cf62fa4c | 309 | const char *l7 = dp_packet_get_tcp_payload(packet); |
f3dd1419 BP |
310 | |
311 | if (flow->dl_type != htons(ETH_TYPE_IP) | |
312 | || flow->nw_proto != IPPROTO_TCP | |
5a51b2cd | 313 | || !l7) { |
f3dd1419 BP |
314 | return NULL; |
315 | } | |
cf62fa4c | 316 | tcp = dp_packet_l4(packet); |
f3dd1419 | 317 | flags = TCP_FLAGS(tcp->tcp_ctl); |
cf62fa4c | 318 | l7_length = (char *) dp_packet_tail(packet) - l7; |
f3dd1419 | 319 | seq = ntohl(get_16aligned_be32(&tcp->tcp_seq)); |
276e2864 BP |
320 | |
321 | /* Construct key. */ | |
322 | memset(&key, 0, sizeof key); | |
323 | key.nw_src = flow->nw_src; | |
324 | key.nw_dst = flow->nw_dst; | |
325 | key.tp_src = flow->tp_src; | |
326 | key.tp_dst = flow->tp_dst; | |
327 | hash = hash_bytes(&key, sizeof key, 0); | |
328 | ||
329 | /* Find existing stream or start a new one for a SYN or if there's data. */ | |
330 | stream = tcp_stream_lookup(r, &key, hash); | |
331 | if (!stream) { | |
332 | if (flags & TCP_SYN || l7_length) { | |
333 | stream = tcp_stream_new(r, &key, hash); | |
334 | stream->seq_no = flags & TCP_SYN ? seq + 1 : seq; | |
335 | } else { | |
336 | return NULL; | |
337 | } | |
338 | } | |
339 | ||
340 | payload = &stream->payload; | |
341 | if (flags & TCP_SYN || !stream->seq_no) { | |
cf62fa4c | 342 | dp_packet_clear(payload); |
f3dd1419 BP |
343 | stream->seq_no = seq + 1; |
344 | return NULL; | |
345 | } else if (flags & (TCP_FIN | TCP_RST)) { | |
346 | tcp_stream_destroy(r, stream); | |
347 | return NULL; | |
348 | } else if (seq == stream->seq_no) { | |
f3dd1419 BP |
349 | /* Shift all of the existing payload to the very beginning of the |
350 | * allocated space, so that we reuse allocated space instead of | |
351 | * continually expanding it. */ | |
cf62fa4c | 352 | dp_packet_shift(payload, (char *) dp_packet_base(payload) - (char *) dp_packet_data(payload)); |
f3dd1419 | 353 | |
cf62fa4c | 354 | dp_packet_put(payload, l7, l7_length); |
276e2864 | 355 | stream->seq_no += l7_length; |
f3dd1419 BP |
356 | return payload; |
357 | } else { | |
358 | return NULL; | |
359 | } | |
360 | } |