Changeset 3fc3267

Timestamp:

02/02/15 16:59:34 (6 years ago)

Author:

Shane Alcock <salcock@…>

Branches:

4.0.1-hotfixes, cachetimestamps, develop, dpdk-ndag, etsilive, 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:

3440627

Parents:

68d3308

Message:

Add protocol decoder functions for GRE and VXLAN

Many thanks to Perry Lorier for providing this patch.

Includes a test-case for VXLAN parsing.

Files:

• lib/Makefile.am (modified) (2 diffs)
• lib/libtrace.h.in (modified) (2 diffs)
• lib/protocols_application.c (added)
• lib/protocols_transport.c (modified) (1 diff)
• test/Makefile (modified) (1 diff)
• test/do-tests.sh (modified) (1 diff)
• test/test-vxlan.c (added)
• test/traces/vxlan.pcap (added)

lib/Makefile.am

@@ -21 +21 @@
 
 if HAVE_LLVM
-BPFJITSOURCE=bpf-jit/bpf-jit.cc 
+BPFJITSOURCE=bpf-jit/bpf-jit.cc
 else
 BPFJITSOURCE=
@@ -54 +54 @@
                 protocols_pktmeta.c protocols_l2.c protocols_l3.c \
                 protocols_transport.c protocols.h protocols_ospf.c \
+                protocols_application.c \
                 $(DAGSOURCE) format_erf.h \
                 $(BPFJITSOURCE) \

lib/libtrace.h.in

@@ -810 +810 @@
 } PACKED libtrace_pppoe_t;
 
+/** Libtrace local definition of GRE (Generalised Routing Protocol) header
+ * RFC2890
+ */
+typedef struct libtrace_gre_t
+{
+    uint16_t flags;         /**< Flags and version */
+    uint16_t ethertype;     /**< Payload ethertype */
+    uint16_t checksum;      /**< Optional checksum */
+    uint16_t reserved1;     /**< Optional reserved */
+    uint16_t key;           /**< Optional key (or Tenant Network ID) */
+    uint16_t seq;           /**< Optional sequence number */
+} PACKED libtrace_gre_t;
+
+#define LIBTRACE_GRE_FLAG_CHECKSUM 0x8000
+#define LIBTRACE_GRE_FLAG_KEY      0x2000
+#define LIBTRACE_GRE_FLAG_SEQ      0x1000
+#define LIBTRACE_GRE_FLAG_VERMASK  0x0007
+
+/** Libtrace local definition of VXLAN Header
+ * (draft-mahalingam-dutt-dcops-vxlan)
+ */
+typedef struct libtrace_vxlan_t
+{
+    uint8_t flags;          /**< Flags */
+    uint8_t reserved1[3];   /**< Reserved */
+    uint8_t vni[3];         /**< VXLAN Network Identifier (VNI) */
+    uint8_t reserved2;
+} PACKED libtrace_vxlan_t;
+
 /** 802.11 header */
 typedef struct libtrace_80211_t {
@@ -2073 +2102 @@
                 uint32_t *remaining);
 
+/** Gets a pointer to the payload following a GRE header
+ * @param         gre       A pointer to the beginning of the GRE header.
+ * @param[in,out] remaining Updated with the number of captured bytes remaining.
+ *
+ * @return A pointer to the GRE payload, or NULL if the GRE header is truncated.
+ *
+ * When calling this function, remaining must contain the number of captured
+ * bytes remaining in the packet starting from the GRE header (including the
+ * GRE header itself). remaining will be updated to contain the number of
+ * bytes remaining after the GRE header has been skipped.
+ *
+ * If the GRE header is complete but there are zero bytes of payload after 
+ * the header, a pointer to where the payload would be is returned and 
+ * remaining will be set to 0.  If the GRE header is incomplete, NULL will be 
+ * returned and remaining will be set to 0. Therefore, it is important to check
+ * the value of remaining after calling this function.
+ */
+DLLEXPORT void *trace_get_payload_from_gre(libtrace_gre_t *gre,
+                uint32_t *remaining);
+
+/** Gets a pointer to the payload following a VXLAN header
+ * @param         udp       A pointer to the beginning of the UDP header.
+ * @param[in,out] remaining Updated with the number of captured bytes remaining.
+ *
+ * @return A pointer to the beginning of the VXLAN header, or NULL if the UDP
+ * header is truncated, or this is not a VXLAN packet.
+ *
+ */
+DLLEXPORT libtrace_vxlan_t *trace_get_vxlan_from_udp(libtrace_udp_t *udp,
+                uint32_t *remaining);
+
+/** Gets a pointer to the payload following a VXLAN header
+ * @param         vxlan       A pointer to the beginning of the VXLAN header.
+ * @param[in,out] remaining Updated with the number of captured bytes remaining.
+ *
+ * @return A pointer to the VXLAN payload, or NULL if the VXLAN header is
+ * truncated.
+ *
+ * When calling this function, remaining must contain the number of captured
+ * bytes remaining in the packet starting from the VXLAN header (including the
+ * VXLAN header itself). remaining will be updated to contain the number of
+ * bytes remaining after the VXLAN header has been skipped.
+ *
+ * If the VXLAN header is complete but there are zero bytes of payload after
+ * the header, a pointer to where the payload would be is returned and
+ * remaining will be set to 0.  If the VXLAN header is incomplete, NULL will be
+ * returned and remaining will be set to 0. Therefore, it is important to check
+ * the value of remaining after calling this function.
+ */
+DLLEXPORT void *trace_get_payload_from_vxlan(libtrace_vxlan_t *vxlan,
+                uint32_t *remaining);
+
 /** Get a pointer to the TCP header (if present)
  * @param packet        The packet to get the TCP header from

lib/protocols_transport.c

@@ -553 +553 @@
         return csum_ptr;
 }
+
+DLLEXPORT void *trace_get_payload_from_gre(libtrace_gre_t *gre,
+        uint32_t *remaining)
+{
+    uint32_t size = 4; /* GRE is 4 bytes long by default */
+    if (remaining && *remaining < size) {
+        *remaining = 0;
+        return NULL;
+    }
+
+    if ((ntohs(gre->flags) & LIBTRACE_GRE_FLAG_CHECKSUM) != 0) {
+        size += 4;  /* An extra 4 bytes. */
+    }
+
+    if ((ntohs(gre->flags) & LIBTRACE_GRE_FLAG_KEY) != 0) {
+        size += 4;  /* An extra 4 bytes. */
+    }
+
+    if ((ntohs(gre->flags) & LIBTRACE_GRE_FLAG_SEQ) != 0) {
+        size += 4;  /* An extra 4 bytes. */
+    }
+
+    if (remaining) {
+        if (*remaining < size) {
+            *remaining = 0;
+            return NULL;
+        }
+        *remaining -= size;
+    }
+    return (char*)gre+size;
+}

test/Makefile

@@ -9 +9 @@
 CFLAGS += $(INCLUDE)
 libdir = $(PREFIX)/lib/.libs:$(PREFIX)/libpacketdump/.libs
-LDLIBS = -L$(PREFIX)/lib/.libs -L$(PREFIX)/libpacketdump/.libs -ltrace -lpacketdump 
+LDLIBS = -L$(PREFIX)/lib/.libs -L$(PREFIX)/libpacketdump/.libs -ltrace -lpacketdump
 
 BINS = test-pcap-bpf test-event test-time test-dir test-wireless test-errors \
-        test-plen test-autodetect test-ports test-fragment test-live test-live-snaplen
+        test-plen test-autodetect test-ports test-fragment test-live \
+        test-live-snaplen test-vxlan
 
 .PHONY: all clean distclean install depend test

test/do-tests.sh

@@ -230 +230 @@
 do_test ./test-autodetect traces/5_packets.erf.xz
 
+echo " * VXLan decode"
+do_test ./test-vxlan
+
 echo
 echo "Tests passed: $OK"