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* Copyright (c) 2009, 2010, 2012 Nicira, Inc.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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#include "pcap-file.h"
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VLOG_DEFINE_THIS_MODULE(pcap);
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uint32_t magic_number; /* magic number */
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uint16_t version_major; /* major version number */
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uint16_t version_minor; /* minor version number */
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int32_t thiszone; /* GMT to local correction */
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uint32_t sigfigs; /* accuracy of timestamps */
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uint32_t snaplen; /* max length of captured packets */
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uint32_t network; /* data link type */
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BUILD_ASSERT_DECL(sizeof(struct pcap_hdr) == 24);
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uint32_t ts_sec; /* timestamp seconds */
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uint32_t ts_usec; /* timestamp microseconds */
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uint32_t incl_len; /* number of octets of packet saved in file */
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uint32_t orig_len; /* actual length of packet */
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BUILD_ASSERT_DECL(sizeof(struct pcaprec_hdr) == 16);
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pcap_open(const char *file_name, const char *mode)
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ovs_assert(!strcmp(mode, "rb") || !strcmp(mode, "wb"));
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file = fopen(file_name, mode);
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VLOG_WARN("%s: failed to open pcap file for %s",
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file_name, mode[0] == 'r' ? "reading" : "writing");
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if (!pcap_read_header(file)) {
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pcap_write_header(file);
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pcap_read_header(FILE *file)
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if (fread(&ph, sizeof ph, 1, file) != 1) {
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int error = ferror(file) ? errno : EOF;
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VLOG_WARN("failed to read pcap header: %s", ovs_retval_to_string(error));
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if (ph.magic_number != 0xa1b2c3d4 && ph.magic_number != 0xd4c3b2a1) {
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VLOG_WARN("bad magic 0x%08"PRIx32" reading pcap file "
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"(expected 0xa1b2c3d4 or 0xd4c3b2a1)", ph.magic_number);
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pcap_write_header(FILE *file)
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/* The pcap reader is responsible for figuring out endianness based on the
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* magic number, so the lack of htonX calls here is intentional. */
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ph.magic_number = 0xa1b2c3d4;
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ph.network = 1; /* Ethernet */
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ignore(fwrite(&ph, sizeof ph, 1, file));
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pcap_read(FILE *file, struct ofpbuf **bufp)
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struct pcaprec_hdr prh;
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if (fread(&prh, sizeof prh, 1, file) != 1) {
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int error = ferror(file) ? errno : EOF;
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VLOG_WARN("failed to read pcap record header: %s",
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ovs_retval_to_string(error));
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/* Calculate length. */
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uint32_t swapped_len = (((len & 0xff000000) >> 24) |
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((len & 0x00ff0000) >> 8) |
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((len & 0x0000ff00) << 8) |
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((len & 0x000000ff) << 24));
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if (swapped_len > 0xffff) {
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VLOG_WARN("bad packet length %zu or %"PRIu32" "
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buf = ofpbuf_new(len);
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data = ofpbuf_put_uninit(buf, len);
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if (fread(data, len, 1, file) != 1) {
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int error = ferror(file) ? errno : EOF;
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VLOG_WARN("failed to read pcap packet: %s",
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ovs_retval_to_string(error));
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pcap_write(FILE *file, struct ofpbuf *buf)
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struct pcaprec_hdr prh;
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prh.incl_len = buf->size;
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prh.orig_len = buf->size;
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ignore(fwrite(&prh, sizeof prh, 1, file));
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ignore(fwrite(buf->data, buf->size, 1, file));