Addition on hidden command "bfd multihop/singlehop" and "ptm-enable" per interface command

CM-10435
Issue: IBGP BFD sessions are created as multi-hop even though peer is single-hop away. This is causing an interop issue with ICOS.
Root Cause: By design all IBGP peers are registered with BFD as multi-hop.
Fix:
• Changed the default behavior of always treating IBGP BFD sessions as mult-hop. shared_network variable is used to determine whether the IBGP peer is single hop or multi-hop away. The logic for determining whether EBGP peer is single hop or multi-hop has not been changed.
• Since the default behavior has been changed, it will cause interop issues between 2.5 and 3.0 IBGP BFD sessions. A new hidden command “bfd multihop/singlehop” has been introduced to overcome the interop issues.

dell-s6000-10(config-router)# neighbor 30.0.2.6 bfd
<2-255> Detect Multiplier
<cr>
dell-s6000-10(config-router)# neighbor 30.0.2.6 bfd multihop
dell-s6000-10(config-router)# no neighbor 30.0.2.6 bfd multihop
dell-s6000-10(config-router)#
dell-s6000-10(config-router)# neighbor 30.0.2.6 bfd multihop
dell-s6000-10(config-router)# do show running-config
!
router bgp 100
neighbor igroup peer-group
neighbor igroup bfd 5 500 500
neighbor igroup bfd multihop
neighbor 30.0.2.2 remote-as 100
neighbor 30.0.2.2 peer-group igroup
neighbor 3101:abc:bcad::2 remote-as 100
neighbor 3101:abc:bcad::2 peer-group igroup
neighbor 30.0.2.6 remote-as 200
neighbor 30.0.2.6 bfd multihop
neighbor 3102:abc:bcad::6 remote-as 200
neighbor 3102:abc:bcad::6 bfd
neighbor 3102:abc:bcad::6 ebgp-multihop 255
!

CM-10260
Issue: “Unable to connect to socket” message keeps getting logged when ptmd process doesn’t exist.
Root Cause: BFD clients (bgpd, ospfd and ospf6d) during initialization try to register with BFD/PTM by default. This results in continuous logging If PTM does not exist since there is no max on number of retries.
Fix:
• Stop the retries to connect to PTM after max reconnect timer of 5 mins is reached.
• Added zebra debug event wrapper to message logging to prevent it from showing by default.

CM-4541
Issue: Addition of a new command "ptm-enable" or "no ptm-enable" per interface to enable/disable PTM link status checks for an interface.
Fix: Currently there is only one ptm-enable global command that enables/disables PTM status updates for all interfaces. This new command will give the handle to individually stop interface from reacting on the PTM status updates.
• by default interface uses the ptm-enable global configuration
• "no ptm-enable" on an interface will disable PTM status updates from taking affect for that interface. This can bring the interface up if it was brought down due to PTM status update.
• "ptm-enable" on an interface will cause the interface to fallback to the global ptm-enable configuration value and will bring the interface up or down based on the last stored PTM status update if global ptm is enabled.

Ticket: CM-10435, CM-10260 and CM-4541
Signed-off-by: Radhika Mahankali
Reviewed-by: Donald Sharp, Kanna Rajagopal

2 files changed, 16 insertions, 6 deletions

diff --git a/lib/bfd.c b/lib/bfd.c
index 4a29b3267..ddf03d4f1 100644
--- a/lib/bfd.c
+++ b/lib/bfd.c
@@ -45,6 +45,7 @@ bfd_info_create(void)
   assert(bfd_info);
 
   bfd_info->status = BFD_STATUS_UNKNOWN;
+  bfd_info->type = BFD_TYPE_NOT_CONFIGURED;
   bfd_info->last_update = 0;
   return bfd_info;
 }
diff --git a/lib/bfd.h b/lib/bfd.h
index b001ae967..31e542d8b 100644
--- a/lib/bfd.h
+++ b/lib/bfd.h
@@ -29,6 +29,7 @@
 #define BFD_CMD_DETECT_MULT_RANGE "<2-255> "
 #define BFD_CMD_MIN_RX_RANGE "<50-60000> "
 #define BFD_CMD_MIN_TX_RANGE "<50-60000>"
+#define BFD_CMD_TYPE "(multihop|singlehop)"
 
 #define BFD_DEF_MIN_RX 300
 #define BFD_MIN_MIN_RX 50
@@ -42,19 +43,27 @@
 
 #define BFD_FLAG_PARAM_CFG (1 << 0) /* parameters have been configured */
 #define BFD_FLAG_BFD_REG   (1 << 1) /* Peer registered with BFD */
+#define BFD_FLAG_BFD_TYPE_MULTIHOP (1 << 2) /* Peer registered with BFD as multihop */
 
 #define BFD_STATUS_UNKNOWN (1 << 0) /* BFD session status never received */
 #define BFD_STATUS_DOWN    (1 << 1) /* BFD session status is down */
 #define BFD_STATUS_UP      (1 << 2) /* BFD session status is up */
 
+enum bfd_sess_type {
+  BFD_TYPE_NOT_CONFIGURED,
+  BFD_TYPE_SINGLEHOP,
+  BFD_TYPE_MULTIHOP
+};
+
 struct bfd_info
 {
-  u_int16_t flags;
-  u_int8_t  detect_mult;
-  u_int32_t desired_min_tx;
-  u_int32_t required_min_rx;
-  time_t    last_update;
-  u_int8_t  status;
+  u_int16_t           flags;
+  u_int8_t            detect_mult;
+  u_int32_t           desired_min_tx;
+  u_int32_t           required_min_rx;
+  time_t              last_update;
+  u_int8_t            status;
+  enum bfd_sess_type  type;
 };
 
 extern struct bfd_info *