Changeset 5745e78 for lib

Timestamp:

04/03/09 11:17:56 (13 years ago)

Author:

Perry Lorier <perry@…>

Branches:

4.0.1-hotfixes, cachetimestamps, develop, dpdk-ndag, etsilive, getfragoff, help, libtrace4, master, ndag_format, pfring, rc-4.0.1, rc-4.0.2, rc-4.0.3, rc-4.0.4, ringdecrementfix, ringperformance, ringtimestampfixes

Children:

af0918a

Parents:

5865c72

Message:

Start trying to flesh out the documentation a bit more to explain our idea of how packets are
layered.

File:

• lib/libtrace.h.in (modified) (3 diffs)

lib/libtrace.h.in

@@ -1020 +1020 @@
  * These functions locate and return a pointer to various headers inside a
  * packet
+ * 
+ * A packet is divided up into several "layers.":
+ *
+ * @li Framing header -- This is the header in a tracefile, or as captured from the network.
+ * generally this includes capture lengths, wire lengths, timestamps, direction information and
+ * any other metadata that is part of the capture format.  
+ * 
+ * @li Metadata header (optional) -- A header that was captured, but was not transmitted over
+ * the wire.  Some examples include RadioTap and Linux_sll headers.  This can be retrieved by
+ * trace_get_packet_meta(), or skipped using trace_get_payload_from_meta().
+ *
+ * @li Layer 2/Link layer/Datalink header -- This can be retrieved by trace_get_layer2(), or
+ * skipped using trace_get_payload_from_layer2().
+ *
+ * @li Layer 3/IP/IPv6 -- This can be retrieved by trace_get_layer3().  As a convenience 
+ * trace_get_ip()/trace_get_ip6() can be used to find an IPv4/IPv6 header.
+ *
+ * @li Layer 5/transport -- These are protocols carried in IPv4/IPv6 frames.  These can be
+ * retrieved using trace_get_transport().
+ * 
  * @{
  */
@@ -1471 +1491 @@
  *                      static storage.
  * @return NULL if there is no source address, or a sockaddr holding a v4 or v6
- * address
+ * address, or on some platforms a sockaddr holding a MAC address.
  */
 DLLEXPORT SIMPLE_FUNCTION
@@ -1482 +1502 @@
  *                      static storage.
  * @return NULL if there is no destination address, or a sockaddr holding a v4
- * or v6 address
+ * or v6 address, or on some platforms a sockaddr holding a MAC address.
  */
 DLLEXPORT SIMPLE_FUNCTION