stats: add version field to stat segment base header

Add a version in the base header of the stat segment
To make support for multiple reader implementations safer.

Change-Id: I6816e2a51a98c2df1e621e80d4ef0b4ba4e9f47b
Type: feature
Signed-off-by: Ole Troan <ot@cisco.com>

6 files changed, 32 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 5cd51f211bd..883ee5bc2ca 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -363,6 +363,12 @@ I:	vcl
 M:	Florin Coras <fcoras@cisco.com>
 F:	src/vcl
 
+Statistics Segment
+I:	stats
+M:	Ole Troan <ot@cisco.com>
+F:	src/vpp/stats/
+F:	src/vpp-api/client/stat_client.[ch]
+
 THE REST
 I:	misc
 C:	Contact vpp-dev Mailing List <vpp-dev@fd.io>
diff --git a/src/vpp-api/client/stat_client.c b/src/vpp-api/client/stat_client.c
index 8991806448a..cfe213d938a 100644
--- a/src/vpp-api/client/stat_client.c
+++ b/src/vpp-api/client/stat_client.c
@@ -509,6 +509,20 @@ stat_segment_index_to_name (uint32_t index)
   return stat_segment_index_to_name_r (index, sm);
 }
 
+uint64_t
+stat_segment_version_r (stat_client_main_t * sm)
+{
+  ASSERT (sm->shared_header);
+  return sm->shared_header->version;
+}
+
+uint64_t
+stat_segment_version (void)
+{
+  stat_client_main_t *sm = &stat_client_main;
+  return stat_segment_version_r (sm);
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vpp-api/client/stat_client.h b/src/vpp-api/client/stat_client.h
index 901ec325522..12faddb7bce 100644
--- a/src/vpp-api/client/stat_client.h
+++ b/src/vpp-api/client/stat_client.h
@@ -78,6 +78,8 @@ double stat_segment_heartbeat (void);
 
 char *stat_segment_index_to_name_r (uint32_t index, stat_client_main_t * sm);
 char *stat_segment_index_to_name (uint32_t index);
+uint64_t stat_segment_version (void);
+uint64_t stat_segment_version_r (stat_client_main_t * sm);
 
 #endif /* included_stat_client_h */
 
diff --git a/src/vpp-api/python/vpp_papi/vpp_stats.py b/src/vpp-api/python/vpp_papi/vpp_stats.py
index de72249ac6b..590549a17bd 100644
--- a/src/vpp-api/python/vpp_papi/vpp_stats.py
+++ b/src/vpp-api/python/vpp_papi/vpp_stats.py
@@ -49,6 +49,7 @@ typedef struct
 
 typedef struct
 {
+  uint64_t version;
   uint64_t epoch;
   uint64_t in_progress;
   uint64_t directory_offset;
@@ -82,6 +83,8 @@ double stat_segment_heartbeat_r (stat_client_main_t * sm);
 int stat_segment_vec_len(void *vec);
 uint8_t **stat_segment_string_vector(uint8_t **string_vector, char *string);
 char *stat_segment_index_to_name_r (uint32_t index, stat_client_main_t * sm);
+uint64_t stat_segment_version(void);
+uint64_t stat_segment_version_r(stat_client_main_t *sm);
 void free(void *ptr);
 """)
 
diff --git a/src/vpp/stats/stat_segment.c b/src/vpp/stats/stat_segment.c
index 61b21babbe3..cef792fc622 100644
--- a/src/vpp/stats/stat_segment.c
+++ b/src/vpp/stats/stat_segment.c
@@ -272,6 +272,9 @@ vlib_map_stat_segment_init (void)
 
   sm->directory_vector_by_name = hash_create_string (0, sizeof (uword));
   sm->shared_header = shared_header = memaddr;
+
+  shared_header->version = STAT_SEGMENT_VERSION;
+
   sm->stat_segment_lockp = clib_mem_alloc (sizeof (clib_spinlock_t));
   clib_spinlock_init (sm->stat_segment_lockp);
 
diff --git a/src/vpp/stats/stat_segment.h b/src/vpp/stats/stat_segment.h
index b9ffedf2169..113eb9a25ad 100644
--- a/src/vpp/stats/stat_segment.h
+++ b/src/vpp/stats/stat_segment.h
@@ -70,11 +70,15 @@ typedef struct
 /* Default stat segment 32m */
 #define STAT_SEGMENT_DEFAULT_SIZE	(32<<20)
 
+/* Shared segment memory layout version */
+#define STAT_SEGMENT_VERSION		1
+
 /*
  * Shared header first in the shared memory segment.
  */
 typedef struct
 {
+  u64 version;
   atomic_int_fast64_t epoch;
   atomic_int_fast64_t in_progress;
   atomic_int_fast64_t directory_offset;