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nacc_fsm: Support receiving Pkt Cell Change Notify in state WAIT_RESOLVE_RAC_CI 

If the message is a duplicate (same tgt cell), simply ignore it.
If the message contains a different tgt cell, restart the resolution:
* Avoid re-creating the socket in that case
* Avoid potentially picking a CTRL response for an older request

Related: SYS#4909
Change-Id: Ia2ed2580bbbdd6d3464833257b0dcb8ec6f8d699
This commit is contained in:
Pau Espin Pedrol 2021-02-10 17:33:13 +01:00
parent 41ff273226
commit 069a637be8
3 changed files with 62 additions and 21 deletions
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65
src/nacc_fsm.c
View File

@ -40,6 +40,9 @@
#define X(s) (1 << (s))
/* Infer CTRL id (seqnum) for a given tgt arfcn+bsic (bsic range: 0-63) */
#define arfcn_bsic_2_ctrl_id(arfcn, bsic) ((arfcn) * 100 + (bsic))
static const struct osmo_tdef_state_timeout nacc_fsm_timeouts[32] = {
[NACC_ST_INITIAL] = {},
[NACC_ST_WAIT_RESOLVE_RAC_CI] = { .T = PCU_TDEF_NEIGH_RESOLVE_TO },
@ -354,15 +357,20 @@ static void st_wait_resolve_rac_ci_on_enter(struct osmo_fsm_inst *fi, uint32_t p
LOGPFSML(fi, LOGL_DEBUG, "No CGI-PS found in cache, resolving " NEIGH_CACHE_ENTRY_KEY_FMT "...\n",
NEIGH_CACHE_ENTRY_KEY_ARGS(&ctx->neigh_key));
rc = osmo_sock_init2_ofd(&ctx->neigh_ctrl_conn->write_queue.bfd,
AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP,
NULL, 0, pcu->vty.neigh_ctrl_addr, pcu->vty.neigh_ctrl_port,
OSMO_SOCK_F_CONNECT);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR,
"Failed to establish CTRL (neighbor resolution) connection to BSC r=%s:%u\n\n",
pcu->vty.neigh_ctrl_addr, pcu->vty.neigh_ctrl_port);
goto err_term;
/* We may have changed to this state previously (eg: we are handling
* another Pkt cell Change Notify with different target). Avoid
* re-creating the socket in that case. */
if (ctx->neigh_ctrl_conn->write_queue.bfd.fd == -1) {
rc = osmo_sock_init2_ofd(&ctx->neigh_ctrl_conn->write_queue.bfd,
AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP,
NULL, 0, pcu->vty.neigh_ctrl_addr, pcu->vty.neigh_ctrl_port,
OSMO_SOCK_F_CONNECT);
if (rc < 0) {
LOGPFSML(fi, LOGL_ERROR,
"Failed to establish CTRL (neighbor resolution) connection to BSC r=%s:%u\n\n",
pcu->vty.neigh_ctrl_addr, pcu->vty.neigh_ctrl_port);
goto err_term;
}
}
cmd = ctrl_cmd_create(ctx, CTRL_TYPE_GET);
@ -371,7 +379,8 @@ static void st_wait_resolve_rac_ci_on_enter(struct osmo_fsm_inst *fi, uint32_t p
goto err_term;
}
cmd->id = talloc_asprintf(cmd, "1");
cmd->id = talloc_asprintf(cmd, "%u", arfcn_bsic_2_ctrl_id(ctx->neigh_key.tgt_arfcn,
ctx->neigh_key.tgt_bsic));
cmd->variable = talloc_asprintf(cmd, "neighbor_resolve_cgi_ps_from_lac_ci.%d.%d.%d.%d",
ctx->neigh_key.local_lac, ctx->neigh_key.local_ci,
ctx->neigh_key.tgt_arfcn, ctx->neigh_key.tgt_bsic);
@ -392,8 +401,25 @@ err_term:
static void st_wait_resolve_rac_ci(struct osmo_fsm_inst *fi, uint32_t event, void *data)
{
struct nacc_fsm_ctx *ctx = (struct nacc_fsm_ctx *)fi->priv;
struct gprs_rlcmac_bts *bts = ctx->ms->bts;
Packet_Cell_Change_Notification_t *notif;
struct neigh_cache_entry_key neigh_key;
switch (event) {
case NACC_EV_RX_CELL_CHG_NOTIFICATION:
notif = (Packet_Cell_Change_Notification_t *)data;
if (fill_neigh_key_from_bts_pkt_cell_chg_not(&neigh_key, bts, notif) < 0) {
LOGPFSML(fi, LOGL_NOTICE, "TargetCell type=0x%x not supported\n",
notif->Target_Cell.UnionType);
nacc_fsm_state_chg(fi, NACC_ST_TX_CELL_CHG_CONTINUE);
return;
}
/* If tgt cell changed, restart resolving it */
if (!neigh_cache_entry_key_eq(&ctx->neigh_key, &neigh_key)) {
ctx->neigh_key = neigh_key;
nacc_fsm_state_chg(fi, NACC_ST_WAIT_RESOLVE_RAC_CI);
}
break;
case NACC_EV_RX_RAC_CI:
/* Assumption: ctx->cgi_ps has been filled by caller of the event */
@ -588,8 +614,10 @@ static struct osmo_fsm_state nacc_fsm_states[] = {
},
[NACC_ST_WAIT_RESOLVE_RAC_CI] = {
.in_event_mask =
X(NACC_EV_RX_CELL_CHG_NOTIFICATION) |
X(NACC_EV_RX_RAC_CI),
.out_state_mask =
X(NACC_ST_WAIT_RESOLVE_RAC_CI) |
X(NACC_ST_WAIT_REQUEST_SI) |
X(NACC_ST_TX_CELL_CHG_CONTINUE),
.name = "WAIT_RESOLVE_RAC_CI",
@ -662,15 +690,28 @@ void nacc_fsm_ctrl_reply_cb(struct ctrl_handle *ctrl, struct ctrl_cmd *cmd, void
{
struct nacc_fsm_ctx *ctx = (struct nacc_fsm_ctx *)data;
char *tmp = NULL, *tok, *saveptr;
unsigned int exp_id;
LOGPFSML(ctx->fi, LOGL_NOTICE, "Received CTRL message: type=%d %s: %s\n",
cmd->type, cmd->variable, osmo_escape_str(cmd->reply, -1));
LOGPFSML(ctx->fi, LOGL_NOTICE, "Received CTRL message: type=%d %s %s: %s\n",
cmd->type, cmd->variable, cmd->id, osmo_escape_str(cmd->reply, -1));
if (cmd->type != CTRL_TYPE_GET_REPLY || !cmd->reply) {
nacc_fsm_state_chg(ctx->fi, NACC_ST_TX_CELL_CHG_CONTINUE);
return;
}
/* Validate it's the seqnum from our last GET cmd, and not from older
* one we may have requested in case MS decided to resend Pkt Cell
* Change Notify with a different tgt cell:
*/
exp_id = arfcn_bsic_2_ctrl_id(ctx->neigh_key.tgt_arfcn, ctx->neigh_key.tgt_bsic);
if ((unsigned int)atoi(cmd->id) != exp_id) {
LOGPFSML(ctx->fi, LOGL_INFO,
"Received CTRL message with id=%s doesn't match our expected last id=%d, ignoring\n",
cmd->id, exp_id);
return;
}
/* TODO: Potentially validate cmd->variable contains same params as we
sent, and that cmd->id matches the original set. We may want to keep
the original cmd around by setting cmd->defer=1 when sending it. */

9
src/neigh_cache.c
View File

@ -27,15 +27,6 @@
#include <neigh_cache.h>
#include <gprs_debug.h>
static inline bool neigh_cache_entry_key_eq(const struct neigh_cache_entry_key *a,
const struct neigh_cache_entry_key *b)
{
return a->local_lac == b->local_lac &&
a->local_ci == b->local_ci &&
a->tgt_arfcn == b->tgt_arfcn &&
a->tgt_bsic == b->tgt_bsic;
}
static void neigh_cache_schedule_cleanup(struct neigh_cache *cache);
static void neigh_cache_cleanup_cb(void *data)
{

9
src/neigh_cache.h
View File

@ -48,6 +48,15 @@ struct neigh_cache_entry_key {
#define NEIGH_CACHE_ENTRY_KEY_FMT "%" PRIu16 "-%" PRIu16 "-%" PRIu16 "-%" PRIu8
#define NEIGH_CACHE_ENTRY_KEY_ARGS(key) (key)->local_lac, (key)->local_ci, (key)->tgt_arfcn, (key)->tgt_bsic
static inline bool neigh_cache_entry_key_eq(const struct neigh_cache_entry_key *a,
const struct neigh_cache_entry_key *b)
{
return a->local_lac == b->local_lac &&
a->local_ci == b->local_ci &&
a->tgt_arfcn == b->tgt_arfcn &&
a->tgt_bsic == b->tgt_bsic;
}
struct neigh_cache_entry {
struct llist_head list; /* to be included in neigh_cache->list */
struct timespec update_ts;