/* * 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; }