diff options
Diffstat (limited to 'src/vnet/unix/pcap.c')
| -rw-r--r-- | src/vnet/unix/pcap.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/vnet/unix/pcap.c b/src/vnet/unix/pcap.c new file mode 100644 index 00000000..bba225f7 --- /dev/null +++ b/src/vnet/unix/pcap.c @@ -0,0 +1,241 @@ +/* + * Copyright (c) 2015 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/* + * pcap.c: libpcap packet capture format + * + * Copyright (c) 2008 Eliot Dresselhaus + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#include <vnet/unix/pcap.h> +#include <sys/fcntl.h> + +/** + * @file + * @brief PCAP function. + * + * Usage: + * + * <code><pre> + * \#include <vnet/unix/pcap.h> + * + * static pcap_main_t pcap = { + * .file_name = "/tmp/ip4", + * .n_packets_to_capture = 2, + * .packet_type = PCAP_PACKET_TYPE_ip, + * }; + * </pre></code> + * + * To add a buffer: + * + * <code><pre>pcap_add_buffer (&pcap, vm, pi0, 128);</pre></code> + * + * File will be written after @c n_packets_to_capture or call to pcap_write (&pcap). + * +*/ + +/** + * @brief Close PCAP file + * + * @return rc - clib_error_t + * + */ +clib_error_t * +pcap_close (pcap_main_t * pm) +{ + close (pm->file_descriptor); + pm->flags &= ~PCAP_MAIN_INIT_DONE; + pm->file_descriptor = -1; + return 0; +} + +/** + * @brief Write PCAP file + * + * @return rc - clib_error_t + * + */ +clib_error_t * +pcap_write (pcap_main_t * pm) +{ + clib_error_t * error = 0; + + if (! (pm->flags & PCAP_MAIN_INIT_DONE)) + { + pcap_file_header_t fh; + int n; + + if (! pm->file_name) + pm->file_name = "/tmp/vnet.pcap"; + + pm->file_descriptor = open (pm->file_name, O_CREAT | O_TRUNC | O_WRONLY, 0664); + if (pm->file_descriptor < 0) + { + error = clib_error_return_unix (0, "failed to open `%s'", pm->file_name); + goto done; + } + + pm->flags |= PCAP_MAIN_INIT_DONE; + pm->n_packets_captured = 0; + pm->n_pcap_data_written = 0; + + /* Write file header. */ + memset (&fh, 0, sizeof (fh)); + fh.magic = 0xa1b2c3d4; + fh.major_version = 2; + fh.minor_version = 4; + fh.time_zone = 0; + fh.max_packet_size_in_bytes = 1 << 16; + fh.packet_type = pm->packet_type; + n = write (pm->file_descriptor, &fh, sizeof (fh)); + if (n != sizeof (fh)) + { + if (n < 0) + error = clib_error_return_unix (0, "write file header `%s'", pm->file_name); + else + error = clib_error_return (0, "short write of file header `%s'", pm->file_name); + goto done; + } + } + + while (vec_len (pm->pcap_data) > pm->n_pcap_data_written) + { + int n = vec_len (pm->pcap_data) - pm->n_pcap_data_written; + + n = write (pm->file_descriptor, + vec_elt_at_index (pm->pcap_data, pm->n_pcap_data_written), n); + + if (n < 0 && unix_error_is_fatal (errno)) + { + error = clib_error_return_unix (0, "write `%s'", pm->file_name); + goto done; + } + pm->n_pcap_data_written += n; + } + + if (pm->n_pcap_data_written >= vec_len (pm->pcap_data)) + { + vec_reset_length (pm->pcap_data); + pm->n_pcap_data_written = 0; + } + + if (pm->n_packets_captured >= pm->n_packets_to_capture) + pcap_close(pm); + + done: + if (error) + { + if (pm->file_descriptor >= 0) + close (pm->file_descriptor); + } + return error; +} + +/** + * @brief Read PCAP file + * + * @return rc - clib_error_t + * + */ +clib_error_t * pcap_read (pcap_main_t * pm) +{ + clib_error_t * error = 0; + int fd, need_swap, n; + pcap_file_header_t fh; + pcap_packet_header_t ph; + + fd = open (pm->file_name, O_RDONLY); + if (fd < 0) + { + error = clib_error_return_unix (0, "open `%s'", pm->file_name); + goto done; + } + + if (read (fd, &fh, sizeof (fh)) != sizeof (fh)) + { + error = clib_error_return_unix (0, "read file header `%s'", pm->file_name); + goto done; + } + + need_swap = 0; + if (fh.magic == 0xd4c3b2a1) + { + need_swap = 1; +#define _(t,f) fh.f = clib_byte_swap_##t (fh.f); + foreach_pcap_file_header; +#undef _ + } + + if (fh.magic != 0xa1b2c3d4) + { + error = clib_error_return (0, "bad magic `%s'", pm->file_name); + goto done; + } + + pm->min_packet_bytes = 0; + pm->max_packet_bytes = 0; + while ((n = read (fd, &ph, sizeof (ph))) != 0) + { + u8 * data; + + if (need_swap) + { +#define _(t,f) ph.f = clib_byte_swap_##t (ph.f); + foreach_pcap_packet_header; +#undef _ + } + + data = vec_new (u8, ph.n_bytes_in_packet); + if (read (fd, data, ph.n_packet_bytes_stored_in_file) != ph.n_packet_bytes_stored_in_file) + { + error = clib_error_return (0, "short read `%s'", pm->file_name); + goto done; + } + + if (vec_len (pm->packets_read) == 0) + pm->min_packet_bytes = pm->max_packet_bytes = ph.n_bytes_in_packet; + else + { + pm->min_packet_bytes = clib_min (pm->min_packet_bytes, ph.n_bytes_in_packet); + pm->max_packet_bytes = clib_max (pm->max_packet_bytes, ph.n_bytes_in_packet); + } + + vec_add1 (pm->packets_read, data); + } + + done: + if (fd >= 0) + close (fd); + return error; + +} |