isisd: fix display crash srv6 sid structure in json

isisd: fix display crash srv6 sid structure in json

Fix a crash when doing "show isis database detail json" in
isis_srv6_topo1 topotest.

> #0  raise (sig=<optimized out>) at ../sysdeps/unix/sysv/linux/raise.c:50
> #1  0x00007fad89524e2c in core_handler (signo=6, siginfo=0x7ffe86a4b8b0, context=0x7ffe86a4b780) at lib/sigevent.c:258
> #2  <signal handler called>
> #3  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
> #4  0x00007fad8904e537 in __GI_abort () at abort.c:79
> #5  0x00007fad8904e40f in __assert_fail_base (fmt=0x7fad891c5688 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=0x7fad8a3e70e8 "json_object_get_type(jso) == json_type_object",
>     file=0x7fad8a3e7064 "./json_object.c", line=590, function=<optimized out>) at assert.c:92
> #6  0x00007fad8905d662 in __GI___assert_fail (assertion=0x7fad8a3e70e8 "json_object_get_type(jso) == json_type_object", file=0x7fad8a3e7064 "./json_object.c", line=590,
>     function=0x7fad8a3e7440 "json_object_object_add_ex") at assert.c:101
> #7  0x00007fad8a3dfe93 in json_object_object_add_ex () from /lib/x86_64-linux-gnu/libjson-c.so.5
> #8  0x000055708e3f8f7f in format_subsubtlv_srv6_sid_structure (sid_struct=0x602000172b70, buf=0x0, json=0x6040000a21d0, indent=6) at isisd/isis_tlvs.c:2880
> #9  0x000055708e3f9acb in isis_format_subsubtlvs (subsubtlvs=0x602000172b50, buf=0x0, json=0x6040000a21d0, indent=6) at isisd/isis_tlvs.c:3022
> #10 0x000055708e3eefb0 in format_item_ext_subtlvs (exts=0x614000047440, buf=0x0, json=0x6040000a2190, indent=2, mtid=2) at isisd/isis_tlvs.c:1313
> #11 0x000055708e3fd599 in format_item_extended_reach (mtid=2, i=0x60300015aed0, buf=0x0, json=0x6040000a1bd0, indent=0) at isisd/isis_tlvs.c:3763
> #12 0x000055708e40d46a in format_item (mtid=2, context=ISIS_CONTEXT_LSP, type=ISIS_TLV_MT_REACH, i=0x60300015aed0, buf=0x0, json=0x6040000a1bd0, indent=0) at isisd/isis_tlvs.c:6789
> #13 0x000055708e40d4fc in format_items_ (mtid=2, context=ISIS_CONTEXT_LSP, type=ISIS_TLV_MT_REACH, items=0x60600021d160, buf=0x0, json=0x6040000a1bd0, indent=0) at isisd/isis_tlvs.c:6804
> #14 0x000055708e40edbc in format_mt_items (context=ISIS_CONTEXT_LSP, type=ISIS_TLV_MT_REACH, m=0x6180000845d8, buf=0x0, json=0x6040000a1bd0, indent=0) at isisd/isis_tlvs.c:7147
> #15 0x000055708e4111e9 in format_tlvs (tlvs=0x618000084480, buf=0x0, json=0x6040000a1bd0, indent=0) at isisd/isis_tlvs.c:7572
> #16 0x000055708e4114ce in isis_format_tlvs (tlvs=0x618000084480, json=0x6040000a1bd0) at isisd/isis_tlvs.c:7613
> #17 0x000055708e36f167 in lsp_print_detail (lsp=0x612000058b40, vty=0x0, json=0x6040000a1bd0, dynhost=1 '\001', isis=0x60d00001f800) at isisd/isis_lsp.c:785
> #18 0x000055708e36f31f in lsp_print_all (vty=0x0, json=0x6040000a0490, head=0x61f000005488, detail=1 '\001', dynhost=1 '\001', isis=0x60d00001f800) at isisd/isis_lsp.c:820
> #19 0x000055708e4379fc in show_isis_database_lspdb_json (json=0x6040000a0450, area=0x61f000005480, level=0, lspdb=0x61f000005488, sysid_str=0x0, ui_level=1) at isisd/isisd.c:2683
> #20 0x000055708e437ef9 in show_isis_database_json (json=0x6040000a0310, sysid_str=0x0, ui_level=1, isis=0x60d00001f800) at isisd/isisd.c:2754
> #21 0x000055708e438357 in show_isis_database_common (vty=0x62e000060400, json=0x6040000a0310, sysid_str=0x0, ui_level=1, isis=0x60d00001f800) at isisd/isisd.c:2788
> #22 0x000055708e438591 in show_isis_database (vty=0x62e000060400, json=0x6040000a0310, sysid_str=0x0, ui_level=1, vrf_name=0x7fad89806300 <vrf_default_name> "default", all_vrf=false)
>     at isisd/isisd.c:2825
> #23 0x000055708e43891d in show_database (self=0x55708e5519c0 <show_database_cmd>, vty=0x62e000060400, argc=5, argv=0x6040000a02d0) at isisd/isisd.c:2855
> #24 0x00007fad893a9767 in cmd_execute_command_real (vline=0x60300015f220, vty=0x62e000060400, cmd=0x0, up_level=0) at lib/command.c:1002
> #25 0x00007fad893a9adc in cmd_execute_command (vline=0x60300015f220, vty=0x62e000060400, cmd=0x0, vtysh=0) at lib/command.c:1061
> #26 0x00007fad893aa728 in cmd_execute (vty=0x62e000060400, cmd=0x621000025900 "show isis database detail json ", matched=0x0, vtysh=0) at lib/command.c:1227

Note that prior to 2e670cd779, there was no crash but only the last
"srv6-sid-structure" was displayed. A "srv6-sid-structure" should be
displayed for each "sid". This commit also fix this.

Was:

> "srv6-lan-endx-sid": [
>   {
>     "sid": "fc00:0:1:1::",
>     "weight": 0,
>     "algorithm": "SPF",
>     "neighbor-id": "0000.0000.0002"
>   },
>   {
>     "sid": "fc00:0:1:2::",
>     "weight": 0,
>     "algorithm": "SPF",
>     "neighbor-id": "0000.0000.0003"
>   }
> ],
> "srv6-sid-structure": {
>   "loc-block-len": 32,
>   "loc-node-len": 16,
>   "func-len": 16,
>   "arg-len": 0
> },

Now (srv6-sid-structure are identical but they are not always):

> "srv6-lan-endx-sid": [
>   {
>     "sid": "fc00:0:1:1::",
>     "algorithm": "SPF",
>     "neighbor-id": "0000.0000.0002",
>     "srv6-sid-structure": {
>       "loc-block-len": 32,
>       "loc-node-len": 16,
>       "func-len": 8,
>       "arg-len": 0
>     },
>   },
>   {
>     "sid": "fc00:0:1:2::",
>     "algorithm": "SPF",
>     "neighbor-id": "0000.0000.0003",
>     "srv6-sid-structure": {
>       "loc-block-len": 32,
>       "loc-node-len": 16,
>       "func-len": 16,
>       "arg-len": 0
>     },
>   }
> ],

Fixes: 2e670cd779 ("isisd: fix display of srv6 subsubtlvs")
Fixes: 648a158802 ("isisd: Add SRv6 End.X SID to Sub-TLV format func")
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>