TT#81500 cfgt: skip $_s and avp id 0

We are getting error:
> <core> [core/usr_avp.c:424]: search_avp(): 0 ID or NULL NAME AVP!

Change-Id: I066b5da7afaf635a44f27344f9881284100a1858

debian/patches/series

@@ -48,6 +48,7 @@ sipwise/pua_dialoginfo-local_identity_dlg_var.patch
 sipwise/pua_dialoginfo-use-lock-when-use_puburi_avps-is-set.patch
 sipwise/dialplan-don-t-stop-loading-rules-on-error.patch
 sipwise/cfgt-skip-tm-vars-T_.patch
+sipwise/cfgt-skip.patch
 sipwise/rtpengine-codec-set-except.patch
 sipwise/topos-don-t-insert-contact-header-for-4xx-replies.patch
 sipwise/0001-sl-Fix-3xx-stats-RPC-marshalling.patch

debian/patches/sipwise/cfgt-skip.patch

@@ -0,0 +1,46 @@
+From: Victor Seva <vseva@sipwise.com>
+Date: Fri, 11 Dec 2020 16:56:18 +0100
+Subject: cfgt: skip $_s and $avp with id 0
+
+---
+ src/modules/cfgt/cfgt_json.c | 13 +++++++++++--
+ 1 file changed, 11 insertions(+), 2 deletions(-)
+
+diff --git a/src/modules/cfgt/cfgt_json.c b/src/modules/cfgt/cfgt_json.c
+index 8089c02..04aa032 100644
+--- a/src/modules/cfgt/cfgt_json.c
++++ b/src/modules/cfgt/cfgt_json.c
+@@ -43,6 +43,10 @@ int _cfgt_get_array_avp_vals(struct sip_msg *msg, pv_param_t *param,
+ 		LM_ERR("invalid name\n");
+ 		return -1;
+ 	}
++	if(name_type == 0 && avp_name.n == 0) {
++		LM_DBG("skip name_type:%d avp_name:%d\n", name_type, avp_name.n);
++		return 0;
++	}
+ 	*jobj = srjson_CreateArray(jdoc);
+ 	if(*jobj == NULL) {
+ 		LM_ERR("cannot create json object\n");
+@@ -286,8 +290,8 @@ int cfgt_get_json(struct sip_msg *msg, unsigned int mask, srjson_doc_t *jdoc,
+ 						el = el->next;
+ 						continue;
+ 					}
+-					if(srjson_GetArraySize(jdoc, jobj) == 0
+-							&& !(mask & CFGT_DP_NULL)) {
++					if(jobj == NULL || (srjson_GetArraySize(jdoc, jobj) == 0
++							&& !(mask & CFGT_DP_NULL))) {
+ 						el = el->next;
+ 						continue;
+ 					}
+@@ -319,6 +323,11 @@ int cfgt_get_json(struct sip_msg *msg, unsigned int mask, srjson_doc_t *jdoc,
+ 					el = el->next;
+ 					continue;
+ 				}
++				if(el->pvname.len > 3 && strncmp("$_s", el->pvname.s, 3) == 0) {
++					LM_DBG("skip dynamic format [%.*s]\n", el->pvname.len, el->pvname.s);
++					el = el->next;
++					continue;
++				}
+ 				if(pv_get_spec_value(msg, &el->spec, &value) != 0) {
+ 					LM_WARN("can't get value[%.*s]\n", el->pvname.len,
+ 							el->pvname.s);