From 373b343e0c6f7864b234557baf7268543054f1e1 Mon Sep 17 00:00:00 2001
From: Vojtech Vilimek <vojtech.vilimek@nic.cz>
Date: Wed, 17 Jul 2024 13:03:26 +0200
Subject: [PATCH] SNMP: snmp_pdu simplification

---
 proto/snmp/bgp4_mib.c   | 159 ++++++++++++++++++++--------------------
 proto/snmp/mib_tree.h   |   4 +-
 proto/snmp/snmp_utils.c |  55 +++++++-------
 proto/snmp/snmp_utils.h |   8 +-
 proto/snmp/subagent.c   |  43 +++++------
 proto/snmp/subagent.h   |  14 +---
 6 files changed, 132 insertions(+), 151 deletions(-)

diff --git a/proto/snmp/bgp4_mib.c b/proto/snmp/bgp4_mib.c
index 9cf4c230..366f49ef 100644
--- a/proto/snmp/bgp4_mib.c
+++ b/proto/snmp/bgp4_mib.c
@@ -36,7 +36,7 @@
   const struct bgp_stats UNUSED *stats; \
   const struct bgp_config UNUSED *config
 
-#define POPULATE_BGP4(addr, proto, conn, stats, config) populate_bgp4(d, &(addr), &(proto), &(conn), &(stats), &(config))
+#define POPULATE_BGP4(addr, proto, conn, stats, config) populate_bgp4(c, &(addr), &(proto), &(conn), &(stats), &(config))
 
 static inline void ip4_to_oid(struct oid *oid, ip4_addr addr);
 
@@ -234,7 +234,7 @@ snmp_bgp_notify_backward_trans(struct snmp_proto *p, struct bgp_proto *bgp)
 void
 snmp_bgp4_register(struct snmp_proto *p)
 {
-  u32 bgp_mib_prefix[] = { 1, BGP4_MIB }; // TODO remove constant
+  u32 bgp_mib_prefix[] = { SNMP_MIB_2, BGP4_MIB };
 
   {
     /* Register the whole BGP4-MIB::bgp root tree node */
@@ -332,10 +332,10 @@ print_bgp_record(const struct bgp_proto *bgp_proto)
 
 
 static inline enum snmp_search_res
-populate_bgp4(struct snmp_data *d, ip4_addr *addr, const struct bgp_proto **proto, const struct bgp_conn
+populate_bgp4(struct snmp_pdu *c, ip4_addr *addr, const struct bgp_proto **proto, const struct bgp_conn
 **conn, const struct bgp_stats **stats, const struct bgp_config **config)
 {
-  const struct oid * const oid = &d->c->sr_vb_start->name;
+  const struct oid * const oid = &c->sr_vb_start->name;
   if (snmp_bgp_valid_ip4(oid) && LOAD_U8(oid->n_subid) == 9)
     *addr = ip4_from_oid(oid);
   else
@@ -344,7 +344,7 @@ populate_bgp4(struct snmp_data *d, ip4_addr *addr, const struct bgp_proto **prot
     return SNMP_SEARCH_NO_INSTANCE;
   }
 
-  struct snmp_bgp_peer *pe = snmp_hash_find(d->p, *addr);
+  struct snmp_bgp_peer *pe = snmp_hash_find(c->p, *addr);
   if (!pe)
   {
     snmp_log("populate() hash find failed");
@@ -356,7 +356,7 @@ populate_bgp4(struct snmp_data *d, ip4_addr *addr, const struct bgp_proto **prot
   if (!ipa_is_ip4(bgp_proto->remote_ip))
   {
     log(L_ERR "%s: Found BGP protocol instance with IPv6 address", bgp_proto->p.name);
-    d->c->error = AGENTX_RES_GEN_ERROR;
+    c->error = AGENTX_RES_GEN_ERROR;
     return SNMP_SEARCH_NO_INSTANCE;
   }
 
@@ -366,7 +366,7 @@ populate_bgp4(struct snmp_data *d, ip4_addr *addr, const struct bgp_proto **prot
     /* Here, we could be in problem as the bgp_proto IP address could be changed */
     log(L_ERR "%s: Stored hash key IP address and peer remote address differ "
       "(%I, %I).", bgp_proto->p.name, proto_ip, pe->peer_ip);
-    d->c->error = AGENTX_RES_GEN_ERROR;
+    c->error = AGENTX_RES_GEN_ERROR;
     return SNMP_SEARCH_NO_INSTANCE;
   }
 
@@ -379,28 +379,28 @@ populate_bgp4(struct snmp_data *d, ip4_addr *addr, const struct bgp_proto **prot
 }
 
 static enum snmp_search_res
-fill_bgp_version(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_bgp_version(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill ver");
-  if (LOAD_U8(d->c->sr_vb_start->name.n_subid) != 3)
+  if (LOAD_U8(c->sr_vb_start->name.n_subid) != 3)
     return SNMP_SEARCH_NO_INSTANCE;
-  d->c->size -= snmp_str_size_from_len(1);
-  snmp_varbind_nstr(d->c, BGP4_VERSIONS, 1);
+  c->size -= snmp_str_size_from_len(1);
+  snmp_varbind_nstr(c, BGP4_VERSIONS, 1);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_local_as(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_local_as(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill as");
-  if (LOAD_U8(d->c->sr_vb_start->name.n_subid) != 3)
+  if (LOAD_U8(c->sr_vb_start->name.n_subid) != 3)
     return SNMP_SEARCH_NO_INSTANCE;
-  snmp_varbind_int(d->c, d->p->bgp_local_as);
+  snmp_varbind_int(c, c->p->bgp_local_as);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_peer_id(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_peer_id(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill peer id");
   enum snmp_search_res res;
@@ -413,14 +413,14 @@ fill_peer_id(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
 
   if (fsm_state == BGP4_MIB_OPENCONFIRM || fsm_state == BGP4_MIB_ESTABLISHED)
     // TODO last
-    snmp_varbind_ip4(d->c, ip4_from_u32(bgp_proto->remote_id));
+    snmp_varbind_ip4(c, ip4_from_u32(bgp_proto->remote_id));
   else
-    snmp_varbind_ip4(d->c, IP4_NONE);
+    snmp_varbind_ip4(c, IP4_NONE);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_peer_state(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_peer_state(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill peer state");
   enum snmp_search_res res;
@@ -431,12 +431,12 @@ fill_peer_state(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
 
   uint fsm_state = snmp_bgp_fsm_state(bgp_proto);
 
-  snmp_varbind_int(d->c, fsm_state);
+  snmp_varbind_int(c, fsm_state);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_admin_status(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_admin_status(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill adm status");
   enum snmp_search_res res;
@@ -446,14 +446,14 @@ fill_admin_status(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
     return res;
 
   if (bgp_proto->p.disabled)
-    snmp_varbind_int(d->c, AGENTX_ADMIN_STOP);
+    snmp_varbind_int(c, AGENTX_ADMIN_STOP);
   else
-    snmp_varbind_int(d->c, AGENTX_ADMIN_START);
+    snmp_varbind_int(c, AGENTX_ADMIN_START);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_neg_version(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_neg_version(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill neg ver");
   enum snmp_search_res res;
@@ -465,14 +465,14 @@ fill_neg_version(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   uint fsm_state = snmp_bgp_fsm_state(bgp_proto);
 
   if (fsm_state == BGP4_MIB_ESTABLISHED || fsm_state == BGP4_MIB_ESTABLISHED)
-    snmp_varbind_int(d->c, BGP4_MIB_NEGOTIATED_VER_VALUE);
+    snmp_varbind_int(c, BGP4_MIB_NEGOTIATED_VER_VALUE);
   else
-    snmp_varbind_int(d->c, BGP4_MIB_NEGOTIATED_VER_NO_VALUE);
+    snmp_varbind_int(c, BGP4_MIB_NEGOTIATED_VER_NO_VALUE);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_local_addr(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_local_addr(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("bgp4_mib fill local addr");
   enum snmp_search_res res;
@@ -484,12 +484,12 @@ fill_local_addr(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_ip4(d->c, ipa_to_ip4(bgp_proto->local_ip));
+  snmp_varbind_ip4(c, ipa_to_ip4(bgp_proto->local_ip));
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_local_port(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_local_port(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("bgp4_mib fill local port");
   enum snmp_search_res res;
@@ -498,12 +498,12 @@ fill_local_port(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_int(d->c, bgp_conf->local_port);
+  snmp_varbind_int(c, bgp_conf->local_port);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_remote_addr(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_remote_addr(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("bgp4_mib fill remote addr");
   enum snmp_search_res res;
@@ -512,12 +512,12 @@ fill_remote_addr(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_ip4(d->c, ipa_to_ip4(bgp_proto->remote_ip));
+  snmp_varbind_ip4(c, ipa_to_ip4(bgp_proto->remote_ip));
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_remote_port(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_remote_port(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("bgp4_mib fill remote port");
   enum snmp_search_res res;
@@ -526,12 +526,12 @@ fill_remote_port(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_int(d->c, bgp_conf->remote_port);
+  snmp_varbind_int(c, bgp_conf->remote_port);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_remote_as(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_remote_as(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill rem as");
   enum snmp_search_res res;
@@ -540,12 +540,12 @@ fill_remote_as(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_int(d->c, bgp_proto->remote_as);
+  snmp_varbind_int(c, bgp_proto->remote_as);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_in_updates(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_in_updates(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill in updates");
   enum snmp_search_res res;
@@ -554,12 +554,12 @@ fill_in_updates(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_counter32(d->c, bgp_stats->rx_updates);
+  snmp_varbind_counter32(c, bgp_stats->rx_updates);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_out_updates(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_out_updates(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill out updates");
   enum snmp_search_res res;
@@ -568,12 +568,12 @@ fill_out_updates(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_counter32(d->c, bgp_stats->tx_updates);
+  snmp_varbind_counter32(c, bgp_stats->tx_updates);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_in_total_msg(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_in_total_msg(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill in total");
   enum snmp_search_res res;
@@ -582,12 +582,12 @@ fill_in_total_msg(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_counter32(d->c, bgp_stats->rx_messages);
+  snmp_varbind_counter32(c, bgp_stats->rx_messages);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_out_total_msg(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_out_total_msg(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill out total");
   enum snmp_search_res res;
@@ -596,12 +596,12 @@ fill_out_total_msg(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_counter32(d->c, bgp_stats->tx_messages);
+  snmp_varbind_counter32(c, bgp_stats->tx_messages);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_last_err(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_last_err(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill last err");
   enum snmp_search_res res;
@@ -613,12 +613,12 @@ fill_last_err(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   char last_error[2];
   snmp_bgp_last_error(bgp_proto, last_error);
 
-  snmp_varbind_nstr(d->c, last_error, 2);
+  snmp_varbind_nstr(c, last_error, 2);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_established_trans(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_established_trans(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill est trans");
   enum snmp_search_res res;
@@ -627,13 +627,13 @@ fill_established_trans(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_counter32(d->c,
+  snmp_varbind_counter32(c,
       bgp_stats->fsm_established_transitions);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_established_time(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_established_time(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill est time");
   enum snmp_search_res res;
@@ -643,13 +643,13 @@ fill_established_time(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
     return res;
 
 
-  snmp_varbind_gauge32(d->c,
+  snmp_varbind_gauge32(c,
 	(current_time() - bgp_proto->last_established) TO_S);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_retry_interval(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_retry_interval(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill retry int");
   enum snmp_search_res res;
@@ -658,12 +658,12 @@ fill_retry_interval(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_int(d->c, bgp_conf->connect_retry_time);
+  snmp_varbind_int(c, bgp_conf->connect_retry_time);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_hold_time(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_hold_time(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill hold time");
   enum snmp_search_res res;
@@ -672,12 +672,12 @@ fill_hold_time(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_int(d->c, (bgp_conn) ?  bgp_conn->hold_time : 0);
+  snmp_varbind_int(c, (bgp_conn) ?  bgp_conn->hold_time : 0);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_keep_alive(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_keep_alive(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill keepalive");
   enum snmp_search_res res;
@@ -687,15 +687,15 @@ fill_keep_alive(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
     return res;
 
   if (!bgp_conf->hold_time)
-    snmp_varbind_int(d->c, 0);
+    snmp_varbind_int(c, 0);
   else
-    snmp_varbind_int(d->c,
+    snmp_varbind_int(c,
       (bgp_conn) ? bgp_conn->keepalive_time : 0);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_hold_time_conf(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_hold_time_conf(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill hold time c");
   enum snmp_search_res res;
@@ -704,12 +704,12 @@ fill_hold_time_conf(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_int(d->c, bgp_conf->hold_time);
+  snmp_varbind_int(c, bgp_conf->hold_time);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_keep_alive_conf(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_keep_alive_conf(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill keepalive c");
   enum snmp_search_res res;
@@ -720,15 +720,15 @@ fill_keep_alive_conf(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
 
 
   if (!bgp_conf->keepalive_time)
-    snmp_varbind_int(d->c, 0);
+    snmp_varbind_int(c, 0);
   else
-    snmp_varbind_int(d->c,
+    snmp_varbind_int(c,
       (bgp_conn) ? bgp_conn->keepalive_time : 0);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_min_as_org_interval(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_min_as_org_interval(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill min org int");
   enum snmp_search_res res;
@@ -738,12 +738,12 @@ fill_min_as_org_interval(struct mib_walk_state *walk UNUSED, struct snmp_data *d
     return res;
 
   /* value should be in 1..65535 but is not supported by bird */
-  snmp_varbind_int(d->c, 0);
+  snmp_varbind_int(c, 0);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_route_adv_interval(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_route_adv_interval(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill rt adv int");
   enum snmp_search_res res;
@@ -753,12 +753,12 @@ fill_route_adv_interval(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
     return res;
 
   /* value should be in 1..65535 but is not supported by bird */
-  snmp_varbind_int(d->c, 0);
+  snmp_varbind_int(c, 0);
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_in_update_elapsed_time(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_in_update_elapsed_time(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fil in elapsed");
   enum snmp_search_res res;
@@ -767,19 +767,19 @@ fill_in_update_elapsed_time(struct mib_walk_state *walk UNUSED, struct snmp_data
   if (res != SNMP_SEARCH_OK)
     return res;
 
-  snmp_varbind_gauge32(d->c,
+  snmp_varbind_gauge32(c,
     (current_time() - bgp_proto->last_rx_update) TO_S
   );
   return SNMP_SEARCH_OK;
 }
 
 static enum snmp_search_res
-fill_local_id(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
+fill_local_id(struct mib_walk_state *walk UNUSED, struct snmp_pdu *c)
 {
   snmp_log("fill local id");
-  if (LOAD_U8(d->c->sr_vb_start->name.n_subid) != 3)
+  if (LOAD_U8(c->sr_vb_start->name.n_subid) != 3)
     return SNMP_SEARCH_NO_INSTANCE;
-  snmp_varbind_ip4(d->c, d->p->bgp_local_id);
+  snmp_varbind_ip4(c, c->p->bgp_local_id);
   return SNMP_SEARCH_OK;
 }
 
@@ -787,10 +787,9 @@ fill_local_id(struct mib_walk_state *walk UNUSED, struct snmp_data *d)
  * bgp4_next_peer
  */
 static int
-bgp4_next_peer(struct mib_walk_state *state, struct snmp_data *data)
+bgp4_next_peer(struct mib_walk_state *state, struct snmp_pdu *c)
 {
-  //struct agentx_varbind *vb = data->c->sr_vb_start;
-  struct oid *oid = &data->c->sr_vb_start->name;
+  struct oid *oid = &c->sr_vb_start->name;
 
   /* BGP4-MIB::bgpPeerIdentifier */
   STATIC_OID(9) bgp4_peer_id = {
@@ -816,14 +815,14 @@ bgp4_next_peer(struct mib_walk_state *state, struct snmp_data *data)
     int old = snmp_oid_size(oid);
     int new = snmp_oid_size(peer_oid);
 
-    if (new - old > 0 && (uint) new - old > data->c->size)
+    if (new - old > 0 && (uint) new - old > c->size)
     {
       snmp_log("bgp4_next_peer small buffer");
-      snmp_manage_tbuf(data->p, data->c);
-      oid = &data->c->sr_vb_start->name;  // TODO fix sr_vb_start in manage_tbuf
+      snmp_manage_tbuf(c->p, c);
+      oid = &c->sr_vb_start->name;  // TODO fix sr_vb_start in manage_tbuf
     }
 
-    data->c->buffer += (new - old);
+    c->buffer += (new - old);
 
     snmp_oid_copy(oid, peer_oid);
     STORE_U8(oid->include, 1);
@@ -840,7 +839,7 @@ bgp4_next_peer(struct mib_walk_state *state, struct snmp_data *data)
   net_fill_ip4(&net, ip4, IP4_MAX_PREFIX_LENGTH);
   struct f_trie_walk_state ws;
 
-  int match = trie_walk_init(&ws, data->p->bgp_trie, &net, 1);
+  int match = trie_walk_init(&ws, c->p->bgp_trie, &net, 1);
 
   if (match && LOAD_U8(oid->include) && precise)
   {
@@ -931,7 +930,7 @@ snmp_bgp4_start(struct snmp_proto *p)
 
   struct {
     u32 id;
-    enum snmp_search_res (*filler)(struct mib_walk_state *state, struct snmp_data *data);
+    enum snmp_search_res (*filler)(struct mib_walk_state *state, struct snmp_pdu *c);
     enum agentx_type type;
     int size;
   } leafs[] = {
@@ -977,7 +976,7 @@ snmp_bgp4_start(struct snmp_proto *p)
   };
 
   struct {
-      enum snmp_search_res (*filler)(struct mib_walk_state *state, struct snmp_data *data);
+      enum snmp_search_res (*filler)(struct mib_walk_state *state, struct snmp_pdu *c);
       enum agentx_type type;
       int size;
   } entry_leafs[] = {
diff --git a/proto/snmp/mib_tree.h b/proto/snmp/mib_tree.h
index 4b15e6d0..58629e57 100644
--- a/proto/snmp/mib_tree.h
+++ b/proto/snmp/mib_tree.h
@@ -41,7 +41,7 @@ struct mib_leaf {
    * AGENTX_INVALID, it is expected that filler() hook will also fill
    * the VarBind type.
    */
-  enum snmp_search_res (*filler)(struct mib_walk_state *state, struct snmp_data *data);
+  enum snmp_search_res (*filler)(struct mib_walk_state *state, struct snmp_pdu *context);
 
   /**
    * call_next - signal multileaf
@@ -56,7 +56,7 @@ struct mib_leaf {
    * Hook may be NULL meaning the leaf node is not multileaf/subtree.
    *
    */
-  int (*call_next)(struct mib_walk_state *state, struct snmp_data *data);
+  int (*call_next)(struct mib_walk_state *state, struct snmp_pdu *context);
 
   /**
    * type of produced VarBind, may be replaced in packet instanciation by
diff --git a/proto/snmp/snmp_utils.c b/proto/snmp/snmp_utils.c
index 394df758..e3fd96ee 100644
--- a/proto/snmp/snmp_utils.c
+++ b/proto/snmp/snmp_utils.c
@@ -12,8 +12,9 @@
 #include <stdio.h>
 
 inline void
-snmp_pdu_context(struct snmp_pdu *pdu, sock *sk)
+snmp_pdu_context(struct snmp_pdu *pdu, struct snmp_proto *p, sock *sk)
 {
+  pdu->p = p;
   pdu->error = AGENTX_RES_NO_ERROR;
   pdu->buffer = sk->tpos;
   pdu->size = sk->tbuf + sk->tbsize - sk->tpos;
@@ -1061,13 +1062,13 @@ snmp_oid_common_ancestor(const struct oid *left, const struct oid *right, struct
  * SNMP MIB tree walking
  */
 struct mib_leaf *
-snmp_walk_init(struct mib_tree *tree, struct mib_walk_state *walk, const struct oid *oid, struct snmp_data *data)
+snmp_walk_init(struct mib_tree *tree, struct mib_walk_state *walk, const struct oid *oid, struct snmp_pdu *c)
 {
   mib_tree_walk_init(walk, tree);
 
-  snmp_vb_to_tx(data->p, oid, data->c);
+  snmp_vb_to_tx(c->p, oid, c);
 
-  mib_node_u *node = mib_tree_find(tree, walk, &data->c->sr_vb_start->name);
+  mib_node_u *node = mib_tree_find(tree, walk, &c->sr_vb_start->name);
 
   // TODO hide me in mib_tree code
   /* mib_tree_find() returns NULL if the oid is longer than existing any path */
@@ -1079,7 +1080,7 @@ snmp_walk_init(struct mib_tree *tree, struct mib_walk_state *walk, const struct
 
 // TODO alter the varbind
 struct mib_leaf *
-snmp_walk_next(struct mib_tree *tree, struct mib_walk_state *walk, struct snmp_data *data)
+snmp_walk_next(struct mib_tree *tree, struct mib_walk_state *walk, struct snmp_pdu *c)
 {
   ASSUME(tree && walk);
 
@@ -1093,52 +1094,52 @@ snmp_walk_next(struct mib_tree *tree, struct mib_walk_state *walk, struct snmp_d
 
   if (mib_node_is_leaf(node) && leaf->call_next)
   {
-    const struct oid *oid = &data->c->sr_vb_start->name;
+    const struct oid *oid = &c->sr_vb_start->name;
     if (mib_tree_walk_oid_compare(walk, oid) > 0)
     {
-      int old = snmp_oid_size(&data->c->sr_vb_start->name);
+      int old = snmp_oid_size(&c->sr_vb_start->name);
       if (mib_tree_walk_to_oid(walk,
-	  &data->c->sr_vb_start->name, 20 * sizeof(u32)))
+	  &c->sr_vb_start->name, 20 * sizeof(u32)))
       {
 	snmp_log("walk_next copy failed");
 	return NULL;
       }
 
-      int new = snmp_oid_size(&data->c->sr_vb_start->name);
-      data->c->buffer += (new - old);
+      int new = snmp_oid_size(&c->sr_vb_start->name);
+      c->buffer += (new - old);
     }
 
-    found = !leaf->call_next(walk, data);
+    found = !leaf->call_next(walk, c);
   }
-  else if (mib_node_is_leaf(node) && LOAD_U8(data->c->sr_vb_start->name.include))
+  else if (mib_node_is_leaf(node) && LOAD_U8(c->sr_vb_start->name.include))
   {
     found = 1;
-    STORE_U8(data->c->sr_vb_start->name.include, 0);
+    STORE_U8(c->sr_vb_start->name.include, 0);
   }
 
-  const struct oid *oid = &data->c->sr_vb_start->name;
+  const struct oid *oid = &c->sr_vb_start->name;
   u32 skip = (walk->id_pos < LOAD_U8(oid->n_subid)) ?
     LOAD_U32(oid->ids[walk->id_pos]) : 0;
   while (!found && (leaf = mib_tree_walk_next_leaf(tree, walk, skip)) != NULL)
   {
     /* mib_tree_walk_next() forces VarBind's name OID overwriting */
-    int old = snmp_oid_size(&data->c->sr_vb_start->name);
+    int old = snmp_oid_size(&c->sr_vb_start->name);
     // TODO autogrow
-    if (mib_tree_walk_to_oid(walk, &data->c->sr_vb_start->name, 20 * sizeof(u32)))
+    if (mib_tree_walk_to_oid(walk, &c->sr_vb_start->name, 20 * sizeof(u32)))
     {
       snmp_log("walk_next copy failed");
       return NULL;
     }
 
-    int new = snmp_oid_size(&data->c->sr_vb_start->name);
-    data->c->buffer += (new - old);
+    int new = snmp_oid_size(&c->sr_vb_start->name);
+    c->buffer += (new - old);
 
-    if (leaf->call_next && !leaf->call_next(walk, data))
+    if (leaf->call_next && !leaf->call_next(walk, c))
       found = 1;
     else if (!leaf->call_next)
       found = 1;
 
-    oid = &data->c->sr_vb_start->name;
+    oid = &c->sr_vb_start->name;
     skip = (walk->id_pos < LOAD_U8(oid->n_subid)) ?
       LOAD_U32(oid->ids[walk->id_pos]) : 0;
   }
@@ -1150,9 +1151,9 @@ snmp_walk_next(struct mib_tree *tree, struct mib_walk_state *walk, struct snmp_d
 }
 
 enum snmp_search_res
-snmp_walk_fill(struct mib_leaf *leaf, struct mib_walk_state *walk, struct snmp_data *data)
+snmp_walk_fill(struct mib_leaf *leaf, struct mib_walk_state *walk, struct snmp_pdu *c)
 {
-  struct agentx_varbind *vb = data->c->sr_vb_start;
+  struct agentx_varbind *vb = c->sr_vb_start;
 
   if (!leaf)
     return SNMP_SEARCH_NO_OBJECT;
@@ -1177,15 +1178,15 @@ snmp_walk_fill(struct mib_leaf *leaf, struct mib_walk_state *walk, struct snmp_d
 
   snmp_log("walk_fill got size %u based on lt %u ls %u, calling filler()", size, leaf->type, leaf->size);
 
-  if (size >= data->c->size)
+  if (size >= c->size)
   {
-    snmp_log("walk_fill small buffer size %d to %d", size, data->c->size);
-    snmp_manage_tbuf(data->p, data->c);
+    snmp_log("walk_fill small buffer size %d to %d", size, c->size);
+    snmp_manage_tbuf(c->p, c);
   }
 
-  enum snmp_search_res res = leaf->filler(walk, data);
+  enum snmp_search_res res = leaf->filler(walk, c);
 
-  vb = data->c->sr_vb_start;
+  vb = c->sr_vb_start;
 
   if (res != SNMP_SEARCH_OK)
     snmp_set_varbind_type(vb, snmp_search_res_to_type(res));
diff --git a/proto/snmp/snmp_utils.h b/proto/snmp/snmp_utils.h
index 43243c68..c4b252e7 100644
--- a/proto/snmp/snmp_utils.h
+++ b/proto/snmp/snmp_utils.h
@@ -62,7 +62,7 @@ void snmp_varbind_duplicate_hdr(struct snmp_proto *p, struct agentx_varbind **vb
  */
 void snmp_session(const struct snmp_proto *p, struct agentx_header *h);
 int snmp_has_context(const struct agentx_header *h);
-void snmp_pdu_context(struct snmp_pdu *pdu, sock *sk);
+void snmp_pdu_context(struct snmp_pdu *pdu, struct snmp_proto *p, sock *sk);
 struct oid *snmp_oid_duplicate(pool *pool, const struct oid *oid);
 struct oid *snmp_oid_blank(struct snmp_proto *p);
 
@@ -114,8 +114,8 @@ enum agentx_type snmp_search_res_to_type(enum snmp_search_res res);
 /*
  * SNMP MIB tree walking
  */
-struct mib_leaf *snmp_walk_init(struct mib_tree *tree, struct mib_walk_state *state, const struct oid *start_rx, struct snmp_data *data);
-struct mib_leaf *snmp_walk_next(struct mib_tree *tree, struct mib_walk_state *state, struct snmp_data *data);
-enum snmp_search_res snmp_walk_fill(struct mib_leaf *leaf, struct mib_walk_state *state, struct snmp_data *data);
+struct mib_leaf *snmp_walk_init(struct mib_tree *tree, struct mib_walk_state *state, const struct oid *start_rx, struct snmp_pdu *context);
+struct mib_leaf *snmp_walk_next(struct mib_tree *tree, struct mib_walk_state *state, struct snmp_pdu *context);
+enum snmp_search_res snmp_walk_fill(struct mib_leaf *leaf, struct mib_walk_state *state, struct snmp_pdu *context);
 
 #endif
diff --git a/proto/snmp/subagent.c b/proto/snmp/subagent.c
index d3094b5e..db77347c 100644
--- a/proto/snmp/subagent.c
+++ b/proto/snmp/subagent.c
@@ -169,7 +169,7 @@ snmp_simple_response(struct snmp_proto *p, enum agentx_response_errs error, u16
 {
   sock *sk = p->sock;
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
   ASSUME(c.size >= sizeof(struct agentx_response));
 
@@ -193,7 +193,7 @@ open_pdu(struct snmp_proto *p, struct oid *oid)
   sock *sk = p->sock;
 
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
 #define TIMEOUT_SIZE sizeof(u32) /* 1B timeout, 3B zero padding */
 
@@ -247,7 +247,7 @@ snmp_notify_pdu(struct snmp_proto *p, struct oid *oid, void *data, uint size, in
   sock *sk = p->sock;
 
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
 #define UPTIME_SIZE \
   sizeof( struct { u32 vb_type; u32 oid_hdr; u32 ids[4]; } )
@@ -352,7 +352,7 @@ un_register_pdu(struct snmp_proto *p, struct oid *oid, u32 bound, uint index, en
   const struct snmp_config *cf = SKIP_BACK(struct snmp_config, cf, p->p.cf);
   sock *sk = p->sock;
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
 #define BOUND_SIZE sizeof(u32)
   /* conditional +4 for upper-bound (optinal field) */
@@ -441,7 +441,7 @@ close_pdu(struct snmp_proto *p, enum agentx_close_reasons reason)
 {
   sock *sk = p->sock;
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
 #define REASON_SIZE sizeof(u32)
   if (c.size < AGENTX_HEADER_SIZE + REASON_SIZE)
@@ -538,7 +538,7 @@ parse_test_set_pdu(struct snmp_proto *p, byte * const pkt_start)
 
   sock *sk = p->sock;
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
   if (c.size < AGENTX_HEADER_SIZE)
   {
@@ -601,7 +601,7 @@ parse_sets_pdu(struct snmp_proto *p, byte * const pkt_start, enum agentx_respons
   }
 
   struct snmp_pdu c;
-  snmp_pdu_context(&c, p->sock);
+  snmp_pdu_context(&c, p, p->sock);
   if (c.size < sizeof(struct agentx_response))
   {
     snmp_log("parse_sets_pdu small buffer");
@@ -1081,18 +1081,14 @@ void
 snmp_get_pdu(struct snmp_proto *p, struct snmp_pdu *c, const struct oid *o_start, struct mib_walk_state *walk)
 {
   snmp_log("snmp_get_pdu()");
-  struct snmp_data d = {
-    .p = p,
-    .c = c,
-  };
 
   struct mib_leaf *leaf;
-  leaf = snmp_walk_init(p->mib_tree, walk, o_start, &d);
+  leaf = snmp_walk_init(p->mib_tree, walk, o_start, c);
 
   snmp_log("found node %p", leaf);
 
   enum snmp_search_res res;
-  res = snmp_walk_fill(leaf, walk, &d);
+  res = snmp_walk_fill(leaf, walk, c);
 
   snmp_log("fill result %u", res);
 
@@ -1103,16 +1099,11 @@ snmp_get_pdu(struct snmp_proto *p, struct snmp_pdu *c, const struct oid *o_start
 int
 snmp_get_next_pdu(struct snmp_proto *p, struct snmp_pdu *c, const struct oid *o_start, struct mib_walk_state *walk)
 {
-  struct snmp_data d = {
-    .p = p,
-    .c = c,
-  };
-
-  (void) snmp_walk_init(p->mib_tree, walk, o_start, &d);
-  struct mib_leaf *leaf = snmp_walk_next(p->mib_tree, walk, &d);
+  (void) snmp_walk_init(p->mib_tree, walk, o_start, c);
+  struct mib_leaf *leaf = snmp_walk_next(p->mib_tree, walk, c);
 
   enum snmp_search_res res;
-  res = snmp_walk_fill(leaf, walk, &d);
+  res = snmp_walk_fill(leaf, walk, c);
 
   if (res != SNMP_SEARCH_OK)
     snmp_set_varbind_type(c->sr_vb_start, AGENTX_END_OF_MIB_VIEW);
@@ -1204,7 +1195,7 @@ parse_gets_pdu(struct snmp_proto *p, byte * const pkt_start)
 
   sock *sk = p->sock;
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
   /*
    * Get-Bulk processing stops if all the varbind have type END_OF_MIB_VIEW
@@ -1396,7 +1387,7 @@ snmp_ping(struct snmp_proto *p)
 
   sock *sk = p->sock;
   struct snmp_pdu c;
-  snmp_pdu_context(&c, sk);
+  snmp_pdu_context(&c, p, sk);
 
   if (c.size < AGENTX_HEADER_SIZE)
     return;
@@ -1480,11 +1471,11 @@ snmp_manage_tbuf2(struct snmp_proto *p, void **ptr, struct snmp_pdu *c)
 }
 
 void
-snmp_tbuf_reserve(struct snmp_data *data, size_t size)
+snmp_tbuf_reserve(struct snmp_pdu *c, size_t size)
 {
-  if (size > data->c->size)
+  if (size > c->size)
   {
-    snmp_manage_tbuf(data->p, data->c);
+    snmp_manage_tbuf(c->p, c);
   }
 }
 
diff --git a/proto/snmp/subagent.h b/proto/snmp/subagent.h
index 09ac3e53..21fd61d1 100644
--- a/proto/snmp/subagent.h
+++ b/proto/snmp/subagent.h
@@ -305,7 +305,8 @@ enum agentx_response_errs {
 
 /* SNMP PDU info */
 struct snmp_pdu {
-  /* TX buffer */
+  struct snmp_proto *p;
+ /* TX buffer */
   byte *buffer;			    /* pointer to buffer */
   uint size;			    /* unused space in buffer */
 
@@ -316,17 +317,6 @@ struct snmp_pdu {
   /* Control */
   enum agentx_response_errs error;  /* storage for result of current action */
   u32 index;			    /* index on which the error was found */
-
-};
-
-/*
- * snmp_data - Comprehensive hadle for Agentx PDU state
- * @p: SNMP protocol instance
- * @c: contextual data for currrently constructed AgentX PDU
- */
-struct snmp_data {
-  struct snmp_proto *p;
-  struct snmp_pdu *c;
 };
 
 struct snmp_packet_info {