2 * Copyright (c) 2009, 2010 Nicira, Inc.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
27 VLOG_DEFINE_THIS_MODULE(pcap);
30 uint32_t magic_number; /* magic number */
31 uint16_t version_major; /* major version number */
32 uint16_t version_minor; /* minor version number */
33 int32_t thiszone; /* GMT to local correction */
34 uint32_t sigfigs; /* accuracy of timestamps */
35 uint32_t snaplen; /* max length of captured packets */
36 uint32_t network; /* data link type */
38 BUILD_ASSERT_DECL(sizeof(struct pcap_hdr) == 24);
41 uint32_t ts_sec; /* timestamp seconds */
42 uint32_t ts_usec; /* timestamp microseconds */
43 uint32_t incl_len; /* number of octets of packet saved in file */
44 uint32_t orig_len; /* actual length of packet */
46 BUILD_ASSERT_DECL(sizeof(struct pcaprec_hdr) == 16);
49 pcap_open(const char *file_name, const char *mode)
53 assert(!strcmp(mode, "rb") || !strcmp(mode, "wb"));
55 file = fopen(file_name, mode);
57 VLOG_WARN("%s: failed to open pcap file for %s",
58 file_name, mode[0] == 'r' ? "reading" : "writing");
63 if (!pcap_read_header(file)) {
68 pcap_write_header(file);
74 pcap_read_header(FILE *file)
77 if (fread(&ph, sizeof ph, 1, file) != 1) {
78 int error = ferror(file) ? errno : EOF;
79 VLOG_WARN("failed to read pcap header: %s", ovs_retval_to_string(error));
82 if (ph.magic_number != 0xa1b2c3d4 && ph.magic_number != 0xd4c3b2a1) {
83 VLOG_WARN("bad magic 0x%08"PRIx32" reading pcap file "
84 "(expected 0xa1b2c3d4 or 0xd4c3b2a1)", ph.magic_number);
91 pcap_write_header(FILE *file)
93 /* The pcap reader is responsible for figuring out endianness based on the
94 * magic number, so the lack of htonX calls here is intentional. */
96 ph.magic_number = 0xa1b2c3d4;
102 ph.network = 1; /* Ethernet */
103 ignore(fwrite(&ph, sizeof ph, 1, file));
107 pcap_read(FILE *file, struct ofpbuf **bufp)
109 struct pcaprec_hdr prh;
117 if (fread(&prh, sizeof prh, 1, file) != 1) {
118 int error = ferror(file) ? errno : EOF;
119 VLOG_WARN("failed to read pcap record header: %s",
120 ovs_retval_to_string(error));
124 /* Calculate length. */
127 uint32_t swapped_len = (((len & 0xff000000) >> 24) |
128 ((len & 0x00ff0000) >> 8) |
129 ((len & 0x0000ff00) << 8) |
130 ((len & 0x000000ff) << 24));
131 if (swapped_len > 0xffff) {
132 VLOG_WARN("bad packet length %zu or %"PRIu32" "
141 buf = ofpbuf_new(len);
142 data = ofpbuf_put_uninit(buf, len);
143 if (fread(data, len, 1, file) != 1) {
144 int error = ferror(file) ? errno : EOF;
145 VLOG_WARN("failed to read pcap packet: %s",
146 ovs_retval_to_string(error));
155 pcap_write(FILE *file, struct ofpbuf *buf)
157 struct pcaprec_hdr prh;
160 prh.incl_len = buf->size;
161 prh.orig_len = buf->size;
162 ignore(fwrite(&prh, sizeof prh, 1, file));
163 ignore(fwrite(buf->data, buf->size, 1, file));