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git.proxmox.com Git - ovs.git/blob - lib/pcap.c
2 * Copyright (c) 2009 Nicira Networks.
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.
26 #define THIS_MODULE VLM_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 */
40 uint32_t ts_sec
; /* timestamp seconds */
41 uint32_t ts_usec
; /* timestamp microseconds */
42 uint32_t incl_len
; /* number of octets of packet saved in file */
43 uint32_t orig_len
; /* actual length of packet */
47 pcap_open(const char *file_name
, const char *mode
)
51 assert(!strcmp(mode
, "rb") || !strcmp(mode
, "wb"));
53 file
= fopen(file_name
, mode
);
55 VLOG_WARN("%s: failed to open pcap file for %s",
56 file_name
, mode
[0] == 'r' ? "reading" : "writing");
61 if (!pcap_read_header(file
)) {
66 pcap_write_header(file
);
72 pcap_read_header(FILE *file
)
75 if (fread(&ph
, sizeof ph
, 1, file
) != 1) {
76 int error
= ferror(file
) ? errno
: EOF
;
77 VLOG_WARN("failed to read pcap header: %s",
78 error
> 0 ? strerror(error
) : "end of file");
81 if (ph
.magic_number
!= 0xa1b2c3d4 && ph
.magic_number
!= 0xd4c3b2a1) {
82 VLOG_WARN("bad magic 0x%08"PRIx32
" reading pcap file "
83 "(expected 0xa1b2c3d4 or 0xd4c3b2a1)", ph
.magic_number
);
90 pcap_write_header(FILE *file
)
92 /* The pcap reader is responsible for figuring out endianness based on the
93 * magic number, so the lack of htonX calls here is intentional. */
95 ph
.magic_number
= 0xa1b2c3d4;
101 ph
.network
= 1; /* Ethernet */
102 fwrite(&ph
, sizeof ph
, 1, file
);
106 pcap_read(FILE *file
, struct ofpbuf
**bufp
)
108 struct pcaprec_hdr prh
;
116 if (fread(&prh
, sizeof prh
, 1, file
) != 1) {
117 int error
= ferror(file
) ? errno
: EOF
;
118 VLOG_WARN("failed to read pcap record header: %s",
119 error
> 0 ? strerror(error
) : "end of file");
123 /* Calculate length. */
126 uint32_t swapped_len
= (((len
& 0xff000000) >> 24) |
127 ((len
& 0x00ff0000) >> 8) |
128 ((len
& 0x0000ff00) << 8) |
129 ((len
& 0x000000ff) << 24));
130 if (swapped_len
> 0xffff) {
131 VLOG_WARN("bad packet length %"PRIu32
" or %"PRIu32
" "
140 buf
= ofpbuf_new(len
);
141 data
= ofpbuf_put_uninit(buf
, len
);
142 if (fread(data
, len
, 1, file
) != 1) {
143 int error
= ferror(file
) ? errno
: EOF
;
144 VLOG_WARN("failed to read pcap packet: %s",
145 error
> 0 ? strerror(error
) : "end of file");
154 pcap_write(FILE *file
, struct ofpbuf
*buf
)
156 struct pcaprec_hdr prh
;
159 prh
.incl_len
= buf
->size
;
160 prh
.orig_len
= buf
->size
;
161 fwrite(&prh
, sizeof prh
, 1, file
);
162 fwrite(buf
->data
, buf
->size
, 1, file
);