/* * Copyright (c) 2019 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. */ #include #include /* * Unfortunately, the "make test" infra won't work with mapped pcap files. * Given enough work [mostly in .py code], one could fix that. */ /** * @file * @brief mapped pcap file support * * Usage: * *
 * \#include 
 *
 * static mpcap_main_t mpcap = {
 *  .file_name = "/tmp/ip4",
 *  .n_packets_to_capture = 2,
 *  .packet_type = MPCAP_PACKET_TYPE_ip,
 * };
 * 
* * To add a buffer: * *
mpcap_add_buffer (&mpcap, vm, pi0, 128);
* * File will be written after @c n_packets_to_capture * or call to mpcap_close * */ /** * @brief Close a mapped pcap file * @param mpcap_main_t * pm * @return rc - clib_error_t * */ clib_error_t * mpcap_close (mpcap_main_t * pm) { u64 actual_size = pm->current_va - pm->file_baseva; /* Not open? Done... */ if ((pm->flags & MPCAP_FLAG_INIT_DONE) == 0) return 0; (void) munmap (pm->file_baseva, pm->max_file_size); pm->file_baseva = 0; pm->current_va = 0; pm->flags &= ~MPCAP_FLAG_INIT_DONE; if ((pm->flags & MPCAP_FLAG_WRITE_ENABLE) == 0) return 0; if (truncate (pm->file_name, actual_size) < 0) clib_unix_warning ("setting file size to %llu", actual_size); return 0; } /** * @brief Initialize a mapped pcap file * @param mpcap_main_t * pm * @return rc - clib_error_t * */ clib_error_t * mpcap_init (mpcap_main_t * pm) { mpcap_file_header_t *fh; u8 zero = 0; int fd; if (pm->flags & MPCAP_FLAG_INIT_DONE) return 0; if (!pm->file_name) pm->file_name = "/tmp/vnet.mpcap"; if (pm->flags & MPCAP_FLAG_THREAD_SAFE) clib_spinlock_init (&pm->lock); fd = open (pm->file_name, O_CREAT | O_TRUNC | O_RDWR, 0664); if (fd < 0) { return clib_error_return_unix (0, "failed to create `%s'", pm->file_name); } if (pm->max_file_size == 0ULL) pm->max_file_size = MPCAP_DEFAULT_FILE_SIZE; /* Round to a multiple of the page size */ pm->max_file_size += (u64) clib_mem_get_page_size (); pm->max_file_size &= ~(u64) clib_mem_get_page_size (); /* Set file size. */ if (lseek (fd, pm->max_file_size - 1, SEEK_SET) == (off_t) - 1) { close (fd); (void) unlink (pm->file_name); return clib_error_return_unix (0, "file size seek"); } if (write (fd, &zero, 1) != 1) { close (fd); (void) unlink (pm->file_name); return clib_error_return_unix (0, "file size write"); } pm->file_baseva = mmap (0, pm->max_file_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (pm->file_baseva == (u8 *) MAP_FAILED) { clib_error_t *error = clib_error_return_unix (0, "mmap"); close (fd); (void) unlink (pm->file_name); return error; } (void) close (fd); pm->flags |= MPCAP_FLAG_INIT_DONE | MPCAP_FLAG_WRITE_ENABLE; pm->n_packets_captured = 0; pm->n_mpcap_data_written = 0; /* Initialize file header */ fh = pm->file_header = (mpcap_file_header_t *) pm->file_baseva; pm->current_va = pm->file_baseva + 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; return 0; } /** * @brief mmap a mapped pcap file, e.g. to read from another process * @param pcap_main_t *pm * @return rc - clib_error_t */ clib_error_t * mpcap_map (mpcap_main_t * pm) { clib_error_t *error = 0; int fd = -1; mpcap_file_header_t *fh; mpcap_packet_header_t *ph; struct stat statb; u64 packets_read = 0; u32 min_packet_bytes = ~0; u32 max_packet_bytes = 0; if (stat (pm->file_name, &statb) < 0) { error = clib_error_return_unix (0, "stat `%s'", pm->file_name); goto done; } fd = open (pm->file_name, O_RDONLY); if (fd < 0) { error = clib_error_return_unix (0, "open `%s'", pm->file_name); goto done; } if (statb.st_size < sizeof (*fh) + sizeof (*ph)) { error = clib_error_return_unix (0, "`%s' is too short", pm->file_name); goto done; } pm->max_file_size = statb.st_size; pm->file_baseva = mmap (0, statb.st_size, PROT_READ, MAP_SHARED, fd, 0); if (pm->file_baseva == (u8 *) MAP_FAILED) { error = clib_error_return_unix (0, "mmap"); goto done; } pm->flags |= MPCAP_FLAG_INIT_DONE; fh = pm->file_header = (mpcap_file_header_t *) pm->file_baseva; ph = (mpcap_packet_header_t *) (fh + 1); if (fh->magic != 0xa1b2c3d4) { error = clib_error_return (0, "bad magic `%s'", pm->file_name); goto done; } /* for the client's convenience, count packets; compute min/max sizes */ while (ph < (mpcap_packet_header_t *) pm->file_baseva + pm->max_file_size) { if (ph->n_packet_bytes_stored_in_file == 0) break; packets_read++; min_packet_bytes = ph->n_packet_bytes_stored_in_file < min_packet_bytes ? ph->n_packet_bytes_stored_in_file : min_packet_bytes; max_packet_bytes = ph->n_packet_bytes_stored_in_file > max_packet_bytes ? ph->n_packet_bytes_stored_in_file : max_packet_bytes; ph = (mpcap_packet_header_t *) (((u8 *) (ph)) + sizeof (*ph) + ph->n_packet_bytes_stored_in_file); } pm->packets_read = packets_read; pm->min_packet_bytes = min_packet_bytes; pm->max_packet_bytes = max_packet_bytes; done: if (fd >= 0) close (fd); return error; } /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */