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daniel gerrit-no-reply at lists.osmocom.orgdaniel has submitted this change. ( https://gerrit.osmocom.org/c/osmo-sgsn/+/22251 )
Change subject: gbproxy: Implement IMSI cache
......................................................................
gbproxy: Implement IMSI cache
When SGSN pooling is enabled we need to route some responses based on
IMSI back to the correct SGSN, e.g. PAGING_PS_REJECT.
The IMSI cache keeps track of this IMSI <-> NSE(SGSN) mapping.
Change-Id: If0a8d6cc1d63f2fb2c395cc5d4373a915bc2cb87
Related: OS#4951, OS#4472
---
M include/osmocom/sgsn/gb_proxy.h
M src/gbproxy/gb_proxy.c
M src/gbproxy/gb_proxy_peer.c
3 files changed, 153 insertions(+), 2 deletions(-)
Approvals:
Jenkins Builder: Verified
laforge: Looks good to me, but someone else must approve
lynxis lazus: Looks good to me, approved
diff --git a/include/osmocom/sgsn/gb_proxy.h b/include/osmocom/sgsn/gb_proxy.h
index 04a3c4b..d988cae 100644
--- a/include/osmocom/sgsn/gb_proxy.h
+++ b/include/osmocom/sgsn/gb_proxy.h
@@ -8,6 +8,7 @@
#include <osmocom/core/hashtable.h>
#include <osmocom/gsm/gsm23003.h>
#include <osmocom/gsm/gsm23236.h>
+#include <osmocom/gsm/protocol/gsm_23_003.h>
#include <osmocom/gprs/gprs_ns2.h>
#include <osmocom/vty/command.h>
@@ -83,6 +84,14 @@
uint8_t timeout;
} tlli_cache;
+ /* imsi<->nse cache used for PAGING REJECT */
+ struct {
+ DECLARE_HASHTABLE(entries, 10);
+ struct osmo_timer_list timer;
+ /* Time in seconds that the entries should be valid */
+ uint8_t timeout;
+ } imsi_cache;
+
/* List of all SGSNs */
struct llist_head sgsns;
@@ -173,7 +182,7 @@
/* TLLI cache */
struct gbproxy_tlli_cache_entry {
- /* linked to gbproxy_config.tlli_cache */
+ /* linked to gbproxy_config.tlli_cache.entries */
struct hlist_node list;
/* TLLI of the entry */
@@ -184,6 +193,19 @@
struct gbproxy_nse *nse;
};
+/* IMSI cache */
+struct gbproxy_imsi_cache_entry {
+ /* linked to gbproxy_config.imsi_cache.entries */
+ struct hlist_node list;
+
+ /* IMSI of the entry */
+ char imsi[OSMO_IMSI_BUF_SIZE];
+ /* When was this entry last seen */
+ time_t tstamp;
+ /* The SGSN where the request came from */
+ struct gbproxy_nse *nse;
+};
+
/* Convenience logging macros for NSE/BVC */
#define LOGPNSE_CAT(NSE, SUBSYS, LEVEL, FMT, ARGS...) \
LOGP(SUBSYS, LEVEL, "NSE(%05u/%s) " FMT, (NSE)->nsei, \
@@ -251,12 +273,18 @@
struct gbproxy_nse *gbproxy_nse_by_nsei(struct gbproxy_config *cfg, uint16_t nsei, uint32_t flags);
struct gbproxy_nse *gbproxy_nse_by_nsei_or_new(struct gbproxy_config *cfg, uint16_t nsei, bool sgsn_facing);
struct gbproxy_nse *gbproxy_nse_by_tlli(struct gbproxy_config *cfg, uint32_t tlli);
+struct gbproxy_nse *gbproxy_nse_by_imsi(struct gbproxy_config *cfg, const char *imsi);
/* TLLI cache */
void gbproxy_tlli_cache_update(struct gbproxy_nse *nse, uint32_t tlli);
void gbproxy_tlli_cache_remove(struct gbproxy_config *cfg, uint32_t tlli);
int gbproxy_tlli_cache_cleanup(struct gbproxy_config *cfg);
+/* IMSI cache */
+void gbproxy_imsi_cache_update(struct gbproxy_nse *nse, const char *imsi);
+void gbproxy_imsi_cache_remove(struct gbproxy_config *cfg, const char *imsi);
+int gbproxy_imsi_cache_cleanup(struct gbproxy_config *cfg);
+
/* SGSN handling */
struct gbproxy_sgsn *gbproxy_sgsn_alloc(struct gbproxy_config *cfg, uint16_t nsei, const char *name);
void gbproxy_sgsn_free(struct gbproxy_sgsn *sgsn);
diff --git a/src/gbproxy/gb_proxy.c b/src/gbproxy/gb_proxy.c
index 7f8260c..d8bca58 100644
--- a/src/gbproxy/gb_proxy.c
+++ b/src/gbproxy/gb_proxy.c
@@ -1405,6 +1405,15 @@
osmo_timer_schedule(&cfg->tlli_cache.timer, 2, 0);
}
+static void imsi_cache_cleanup(void *data)
+{
+ struct gbproxy_config *cfg = data;
+ gbproxy_imsi_cache_cleanup(cfg);
+
+ /* TODO: Disable timer when cache is empty */
+ osmo_timer_schedule(&cfg->imsi_cache.timer, 2, 0);
+}
+
int gbproxy_init_config(struct gbproxy_config *cfg)
{
struct timespec tp;
@@ -1414,6 +1423,7 @@
cfg->pool.null_nri_ranges = osmo_nri_ranges_alloc(cfg);
/* TODO: Make configurable */
cfg->tlli_cache.timeout = 10;
+ cfg->imsi_cache.timeout = 10;
hash_init(cfg->bss_nses);
hash_init(cfg->sgsn_nses);
@@ -1424,6 +1434,10 @@
osmo_timer_setup(&cfg->tlli_cache.timer, tlli_cache_cleanup, cfg);
osmo_timer_schedule(&cfg->tlli_cache.timer, 2, 0);
+ /* We could also combine both timers */
+ osmo_timer_setup(&cfg->imsi_cache.timer, imsi_cache_cleanup, cfg);
+ osmo_timer_schedule(&cfg->imsi_cache.timer, 2, 0);
+
cfg->ctrg = rate_ctr_group_alloc(tall_sgsn_ctx, &global_ctrg_desc, 0);
if (!cfg->ctrg) {
LOGP(DGPRS, LOGL_ERROR, "Cannot allocate global counter group!\n");
diff --git a/src/gbproxy/gb_proxy_peer.c b/src/gbproxy/gb_proxy_peer.c
index 104902b..1d9352d 100644
--- a/src/gbproxy/gb_proxy_peer.c
+++ b/src/gbproxy/gb_proxy_peer.c
@@ -25,11 +25,13 @@
#include <osmocom/sgsn/debug.h>
#include <osmocom/gprs/protocol/gsm_08_18.h>
+#include <osmocom/core/crc16.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/rate_ctr.h>
#include <osmocom/core/stats.h>
#include <osmocom/core/talloc.h>
+#include <osmocom/core/utils.h>
#include <osmocom/gsm/tlv.h>
#include <string.h>
@@ -331,6 +333,101 @@
}
}
return count;
+
+}
+/***********************************************************************
+ * IMSI cache
+ ***********************************************************************/
+static inline uint16_t _checksum_imsi(const char *imsi)
+{
+ size_t len = strlen(imsi);
+ return osmo_crc16(0, (const uint8_t *)imsi, len);
+}
+
+static inline struct gbproxy_imsi_cache_entry *_get_imsi_entry(struct gbproxy_config *cfg, const char *imsi)
+{
+ struct gbproxy_imsi_cache_entry *cache_entry;
+ uint16_t imsi_hash = _checksum_imsi(imsi);
+
+ hash_for_each_possible(cfg->imsi_cache.entries, cache_entry, list, imsi_hash) {
+ if (!strncmp(cache_entry->imsi, imsi, sizeof(cache_entry->imsi)))
+ return cache_entry;
+ }
+ return NULL;
+}
+
+void gbproxy_imsi_cache_update(struct gbproxy_nse *nse, const char *imsi)
+{
+ struct gbproxy_config *cfg = nse->cfg;
+ struct timespec now;
+ struct gbproxy_imsi_cache_entry *cache_entry = _get_imsi_entry(cfg, imsi);
+ uint16_t imsi_hash = _checksum_imsi(imsi);
+
+ osmo_clock_gettime(CLOCK_MONOTONIC, &now);
+
+ if (cache_entry) {
+ /* Update the entry if it already exists */
+ cache_entry->nse = nse;
+ cache_entry->tstamp = now.tv_sec;
+ return;
+ }
+
+ cache_entry = talloc_zero(cfg, struct gbproxy_imsi_cache_entry);
+ OSMO_STRLCPY_ARRAY(cache_entry->imsi, imsi);
+ cache_entry->nse = nse;
+ cache_entry->tstamp = now.tv_sec;
+ hash_add(cfg->imsi_cache.entries, &cache_entry->list, imsi_hash);
+}
+
+static void _imsi_cache_remove_nse(struct gbproxy_nse *nse) {
+ uint i;
+ struct gbproxy_config *cfg = nse->cfg;
+ struct gbproxy_imsi_cache_entry *imsi_cache;
+ struct hlist_node *tmp;
+
+ hash_for_each_safe(cfg->imsi_cache.entries, i, tmp, imsi_cache, list) {
+ if (imsi_cache->nse == nse) {
+ hash_del(&imsi_cache->list);
+ talloc_free(imsi_cache);
+ }
+ }
+}
+
+void gbproxy_imsi_cache_remove(struct gbproxy_config *cfg, const char *imsi)
+{
+ struct gbproxy_imsi_cache_entry *imsi_cache;
+ struct hlist_node *tmp;
+ uint16_t imsi_hash = _checksum_imsi(imsi);
+
+ hash_for_each_possible_safe(cfg->imsi_cache.entries, imsi_cache, tmp, list, imsi_hash) {
+ if (!(strncmp(imsi_cache->imsi, imsi, sizeof(imsi_cache->imsi)))) {
+ hash_del(&imsi_cache->list);
+ talloc_free(imsi_cache);
+ return;
+ }
+ }
+}
+
+int gbproxy_imsi_cache_cleanup(struct gbproxy_config *cfg)
+{
+ int i, count = 0;
+ struct gbproxy_imsi_cache_entry *imsi_cache;
+ struct hlist_node *tmp;
+ struct timespec now;
+ time_t expiry;
+
+ osmo_clock_gettime(CLOCK_MONOTONIC, &now);
+ expiry = now.tv_sec - cfg->imsi_cache.timeout;
+
+ hash_for_each_safe(cfg->imsi_cache.entries, i, tmp, imsi_cache, list) {
+ if (imsi_cache->tstamp < expiry) {
+ count++;
+ LOGP(DGPRS, LOGL_NOTICE, "Cache entry for IMSI %s expired, removing\n", imsi_cache->imsi);
+ hash_del(&imsi_cache->list);
+ talloc_free(imsi_cache);
+ }
+ }
+ return count;
}
/***********************************************************************
@@ -374,8 +471,9 @@
LOGPNSE_CAT(nse, DOBJ, LOGL_INFO, "NSE Destroying\n");
hash_del(&nse->list);
- /* Clear the tlli_cache from this NSE */
+ /* Clear the cache entries of this NSE */
_tlli_cache_remove_nse(nse);
+ _imsi_cache_remove_nse(nse);
hash_for_each_safe(nse->bvcs, i, tmp, bvc, list)
gbproxy_bvc_free(bvc);
@@ -444,6 +542,17 @@
return NULL;
}
+struct gbproxy_nse *gbproxy_nse_by_imsi(struct gbproxy_config *cfg, const char *imsi)
+{
+ struct gbproxy_imsi_cache_entry *imsi_cache;
+ uint16_t imsi_hash = _checksum_imsi(imsi);
+
+ hash_for_each_possible(cfg->imsi_cache.entries, imsi_cache, list, imsi_hash) {
+ if (!strncmp(imsi_cache->imsi, imsi, sizeof(imsi_cache->imsi)))
+ return imsi_cache->nse;
+ }
+ return NULL;
+}
/***********************************************************************
* SGSN - Serving GPRS Support Node
--
To view, visit https://gerrit.osmocom.org/c/osmo-sgsn/+/22251
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Gerrit-Project: osmo-sgsn
Gerrit-Branch: master
Gerrit-Change-Id: If0a8d6cc1d63f2fb2c395cc5d4373a915bc2cb87
Gerrit-Change-Number: 22251
Gerrit-PatchSet: 2
Gerrit-Owner: daniel <dwillmann at sysmocom.de>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: daniel <dwillmann at sysmocom.de>
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-Reviewer: lynxis lazus <lynxis at fe80.eu>
Gerrit-MessageType: merged
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