vppinfra: add mapped pcap file support

Type: feature

Change-Id: Ic720d56a6f8901efde2a58519bc9aa553205a9a6
Signed-off-by: Gary Boon <gboon@cisco.com>
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 247 insertions, 0 deletions

diff --git a/src/vppinfra/mpcap.c b/src/vppinfra/mpcap.c
new file mode 100644
index 00000000000..902f52f1870
--- /dev/null
+++ b/src/vppinfra/mpcap.c
@@ -0,0 +1,247 @@
+/*
+ * 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 <sys/fcntl.h>
+#include <vppinfra/mpcap.h>
+
+/*
+ * 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:
+ *
+ * <code><pre>
+ * \#include <vnet/unix/mpcap.h>
+ *
+ * static mpcap_main_t mpcap = {
+ *  .file_name = "/tmp/ip4",
+ *  .n_packets_to_capture = 2,
+ *  .packet_type = MPCAP_PACKET_TYPE_ip,
+ * };
+ * </pre></code>
+ *
+ * To add a buffer:
+ *
+ *  <code><pre>mpcap_add_buffer (&mpcap, vm, pi0, 128);</pre></code>
+ *
+ * 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:
+ */