pespin has uploaded this change for review.
Implement ASP loadsharing
Calculate AS Extended SLS (7 bit) out of OPC (12 bits) and SLS (4 bits)
based on VTY configuration.
Assign a normal destination ASP for each AS-eSLS and try to use it
whenever possible; fallback to an alternative ASP when normal ASP is not
available.
Related: SYS#7112
Change-Id: I5f47e40b70ed566034cd1533b71e21fc03e94f6c
---
M src/osmo_ss7_as.c
M src/osmo_ss7_vty.c
M src/ss7_as.h
M src/xua_as_fsm.c
M tests/vty/osmo_stp_test.vty
5 files changed, 223 insertions(+), 11 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/libosmo-sigtran refs/changes/08/39408/1
diff --git a/src/osmo_ss7_as.c b/src/osmo_ss7_as.c
index eb655ca..ccf929f 100644
--- a/src/osmo_ss7_as.c
+++ b/src/osmo_ss7_as.c
@@ -33,6 +33,7 @@
#include <osmocom/sigtran/osmo_ss7.h>
#include <osmocom/sigtran/protocol/m3ua.h>
+#include <osmocom/sigtran/mtp_sap.h>
#include "ss7_as.h"
#include "ss7_asp.h"
@@ -153,6 +154,14 @@
LOGPAS(as, DLSS7, LOGL_INFO, "Removing ASP %s from AS\n", asp->cfg.name);
+ /* Remove route from AS-eSLS table: */
+ for (unsigned int i = 0; i < ARRAY_SIZE(as->aesls_table); i++) {
+ if (as->aesls_table[i].normal_asp == asp)
+ as->aesls_table[i].normal_asp = NULL;
+ if (as->aesls_table[i].alt_asp == asp)
+ as->aesls_table[i].alt_asp = NULL;
+ }
+
for (i = 0; i < ARRAY_SIZE(as->cfg.asps); i++) {
if (as->cfg.asps[i] == asp) {
as->cfg.asps[i] = NULL;
@@ -254,6 +263,83 @@
return asp;
}
+static as_ext_sls_t osmo_ss7_instance_calc_itu_as_ext_sls(const struct osmo_ss7_as *as, uint32_t opc, uint8_t sls)
+{
+ uint16_t opc12;
+ uint8_t opc3;
+ as_ext_sls_t as_ext_sls;
+
+ if (as->cfg.loadshare.opc_sls) {
+ /* Take 12 bits from OPC according to config: */
+ opc12 = (uint16_t)((opc >> as->cfg.loadshare.opc_shift) & 0x3fff);
+
+ /* Derivate 3-bit value from 12-bit value: */
+ opc3 = (((opc12 >> 9) & 0x07) ^
+ ((opc12 >> 6) & 0x07) ^
+ ((opc12 >> 3) & 0x07) ^
+ (opc12 & 0x07)) & 0x07;
+
+ /* Generate 7 bit AS-extended-SLS: 3-bit OPC + 4 bit SLS: */
+ as_ext_sls = (opc3 << 4) | ((sls) & 0x0f);
+ OSMO_ASSERT(as_ext_sls < NUM_AS_EXT_SLS);
+ } else {
+ as_ext_sls = sls;
+ }
+
+ /* Pick extended-SLS bits according to config: */
+ as_ext_sls = as_ext_sls >> as->cfg.loadshare.sls_shift;
+ return as_ext_sls;
+}
+
+/* ITU Q.704 4.2.1: "current signalling link". Pick available already selected ASP */
+static struct osmo_ss7_asp *current_asp(const struct osmo_ss7_as *as, const struct osmo_ss7_as_esls_entry *aeslse)
+{
+ if (aeslse->normal_asp && osmo_ss7_asp_active(aeslse->normal_asp))
+ return aeslse->normal_asp;
+ if (aeslse->alt_asp && osmo_ss7_asp_active(aeslse->alt_asp))
+ return aeslse->alt_asp;
+ return NULL;
+}
+
+static struct osmo_ss7_asp *ss7_as_select_asp_loadshare(struct osmo_ss7_as *as, const struct osmo_mtp_transfer_param *mtp)
+{
+ as_ext_sls_t as_ext_sls;
+ struct osmo_ss7_asp *asp;
+
+ as_ext_sls = osmo_ss7_instance_calc_itu_as_ext_sls(as, mtp->opc, mtp->sls);
+ struct osmo_ss7_as_esls_entry *aeslse = &as->aesls_table[as_ext_sls];
+
+ /* First check if we have a cached route for this ESLS */
+ asp = current_asp(as, aeslse);
+ if (asp) {
+ if (asp == aeslse->normal_asp) {
+ /* We can transmit over normal ASP.
+ * Clean up alternative ASP since it's not needed anymore */
+ aeslse->alt_asp = NULL;
+ return asp;
+ }
+ /* We can transmit over alternative ASP: */
+ return asp;
+ }
+
+ /* No current ASP available, try to find a new current ASP: */
+
+ /* No normal route selected yet: */
+ if (!aeslse->normal_asp) {
+ asp = ss7_as_select_asp_roundrobin(as);
+ /* Either a normal route was selected or none found: */
+ aeslse->normal_asp = asp;
+ return asp;
+ }
+
+ /* Normal ASP unavailable and no alternative ASP (or unavailable too).
+ * start ITU Q.704 section 7 "forced rerouting" procedure: */
+ asp = ss7_as_select_asp_roundrobin(as);
+ if (asp)
+ aeslse->alt_asp = asp;
+ return asp;
+}
+
/* returns NULL if multiple ASPs would need to be selected. */
static struct osmo_ss7_asp *ss7_as_select_asp_broadcast(struct osmo_ss7_as *as)
{
@@ -278,7 +364,7 @@
* This function returns NULL too if multiple ASPs would be selected, ie. AS is
* configured in broadcast mode and more than one ASP is configured.
*/
-struct osmo_ss7_asp *osmo_ss7_as_select_asp(struct osmo_ss7_as *as)
+struct osmo_ss7_asp *ss7_as_select_asp(struct osmo_ss7_as *as, const struct osmo_mtp_transfer_param *mtp)
{
struct osmo_ss7_asp *asp = NULL;
@@ -287,9 +373,45 @@
asp = ss7_as_select_asp_override(as);
break;
case OSMO_SS7_AS_TMOD_LOADSHARE:
- /* TODO: actually use the SLS value to ensure same SLS goes
- * through same ASP. Not strictly required by M3UA RFC, but
- * would fit the overall principle. */
+ asp = ss7_as_select_asp_loadshare(as, mtp);
+ case OSMO_SS7_AS_TMOD_ROUNDROBIN:
+ asp = ss7_as_select_asp_roundrobin(as);
+ break;
+ case OSMO_SS7_AS_TMOD_BCAST:
+ return ss7_as_select_asp_broadcast(as);
+ case _NUM_OSMO_SS7_ASP_TMOD:
+ OSMO_ASSERT(false);
+ }
+
+ if (!asp) {
+ LOGPFSM(as->fi, "No selectable ASP in AS\n");
+ return NULL;
+ }
+ return asp;
+}
+/*! Select an AS to transmit a message, according to AS configuration and ASP availability.
+ * \param[in] as Application Server.
+ * \returns asp to send the message to, NULL if no possible asp found
+ *
+ * This function returns NULL too if multiple ASPs would be selected, ie. AS is
+ * configured in broadcast mode and more than one ASP is configured.
+ */
+struct osmo_ss7_asp *osmo_ss7_as_select_asp(struct osmo_ss7_as *as)
+{
+ struct osmo_ss7_asp *asp = NULL;
+ struct osmo_mtp_transfer_param mtp;
+
+ switch (as->cfg.mode) {
+ case OSMO_SS7_AS_TMOD_OVERRIDE:
+ asp = ss7_as_select_asp_override(as);
+ break;
+ case OSMO_SS7_AS_TMOD_LOADSHARE:
+ /* We don't have OPC and SLS information in this API (which is
+ actually only used to route IPA msgs nowadays by osmo-bsc, so we
+ don't care. Use hardcoded value to provide some fallback for this scenario: */
+ mtp = (struct osmo_mtp_transfer_param){0};
+ asp = ss7_as_select_asp_loadshare(as, &mtp);
+ break;
case OSMO_SS7_AS_TMOD_ROUNDROBIN:
asp = ss7_as_select_asp_roundrobin(as);
break;
diff --git a/src/osmo_ss7_vty.c b/src/osmo_ss7_vty.c
index 6b404b3..852aca3 100644
--- a/src/osmo_ss7_vty.c
+++ b/src/osmo_ss7_vty.c
@@ -1916,10 +1916,9 @@
DEFUN_USRATTR(as_traf_mode, as_traf_mode_cmd,
OSMO_SCCP_LIB_ATTR_RSTRT_ASP,
- "traffic-mode (broadcast | loadshare | roundrobin | override)",
+ "traffic-mode (broadcast | roundrobin | override)",
"Specifies traffic mode of operation of the ASP within the AS\n"
"Broadcast to all ASP within AS\n"
- "Share Load among all ASP within AS\n"
"Round-Robin between all ASP within AS\n"
"Override\n")
{
@@ -1930,6 +1929,36 @@
return CMD_SUCCESS;
}
+DEFUN_USRATTR(as_traf_mode_loadshare, as_traf_mode_loadshare_cmd,
+ OSMO_SCCP_LIB_ATTR_RSTRT_ASP,
+ "traffic-mode loadshare [bindings] [sls] [opc-sls] [opc-shift] [<0-2>]",
+ "Specifies traffic mode of operation of the ASP within the AS\n"
+ "Share Load among all ASP within AS\n"
+ "Configure Loadshare parameters\n"
+ "Configure Loadshare SLS generation parameters\n"
+ "Generate extended SLS with OPC information\n"
+ "Shift OPC bits used during routing decision\n"
+ "How many bits from ITU OPC field (starting from least-significant-bit) to skip (default=0). 6 bits are always used\n"
+ )
+{
+ struct osmo_ss7_as *as = vty->index;
+
+ as->cfg.mode = OSMO_SS7_AS_TMOD_LOADSHARE;
+ as->cfg.mode_set_by_vty = true;
+ if (argc < 3) {
+ as->cfg.loadshare.opc_sls = false;
+ as->cfg.loadshare.opc_shift = 0;
+ return CMD_SUCCESS;
+ }
+ as->cfg.loadshare.opc_sls = true;
+ if (argc < 5) {
+ as->cfg.loadshare.opc_shift = 0;
+ return CMD_SUCCESS;
+ }
+ as->cfg.loadshare.opc_shift = atoi(argv[4]);
+ return CMD_SUCCESS;
+}
+
DEFUN_USRATTR(as_no_traf_mode, as_no_traf_mode_cmd,
OSMO_SCCP_LIB_ATTR_RSTRT_ASP,
"no traffic-mode",
@@ -1939,6 +1968,22 @@
as->cfg.mode = 0;
as->cfg.mode_set_by_vty = false;
+
+ as->cfg.loadshare.sls_shift = 0;
+ as->cfg.loadshare.opc_sls = false;
+ as->cfg.loadshare.opc_shift = 0;
+ return CMD_SUCCESS;
+}
+
+DEFUN_ATTR(as_sls_shift, as_sls_shift_cmd,
+ "sls-shift <0-3>",
+ "Shift SLS bits used during routing decision\n"
+ "How many bits from SLS field (starting from least-significant-bit) to skip\n",
+ CMD_ATTR_IMMEDIATE)
+{
+ struct osmo_ss7_as *as = vty->index;
+ as->cfg.loadshare.sls_shift = atoi(argv[0]);
+
return CMD_SUCCESS;
}
@@ -2157,9 +2202,21 @@
continue;
vty_out(vty, " asp %s%s", asp->cfg.name, VTY_NEWLINE);
}
- if (as->cfg.mode_set_by_vty)
- vty_out(vty, " traffic-mode %s%s",
- osmo_ss7_as_traffic_mode_name(as->cfg.mode), VTY_NEWLINE);
+ if (as->cfg.mode_set_by_vty) {
+ vty_out(vty, " traffic-mode %s", osmo_ss7_as_traffic_mode_name(as->cfg.mode));
+ if (as->cfg.mode == OSMO_SS7_AS_TMOD_LOADSHARE) {
+ if (as->cfg.loadshare.opc_sls) {
+ vty_out(vty, " bindings sls opc-sls");
+ if (as->cfg.loadshare.opc_shift != 0)
+ vty_out(vty, " opc-shift %u%s", as->cfg.loadshare.opc_shift, VTY_NEWLINE);
+ }
+ }
+ vty_out(vty, "%s", VTY_NEWLINE);
+
+ if (as->cfg.loadshare.sls_shift != 0)
+ vty_out(vty, " sls-shift %u%s", as->cfg.loadshare.sls_shift, VTY_NEWLINE);
+ }
+
if (as->cfg.recovery_timeout_msec != 2000) {
vty_out(vty, " recovery-timeout %u%s",
as->cfg.recovery_timeout_msec, VTY_NEWLINE);
@@ -3092,7 +3149,9 @@
install_lib_element(L_CS7_AS_NODE, &as_asp_cmd);
install_lib_element(L_CS7_AS_NODE, &as_no_asp_cmd);
install_lib_element(L_CS7_AS_NODE, &as_traf_mode_cmd);
+ install_lib_element(L_CS7_AS_NODE, &as_traf_mode_loadshare_cmd);
install_lib_element(L_CS7_AS_NODE, &as_no_traf_mode_cmd);
+ install_lib_element(L_CS7_AS_NODE, &as_sls_shift_cmd);
install_lib_element(L_CS7_AS_NODE, &as_recov_tout_cmd);
install_lib_element(L_CS7_AS_NODE, &as_qos_class_cmd);
install_lib_element(L_CS7_AS_NODE, &as_rout_key_cmd);
diff --git a/src/ss7_as.h b/src/ss7_as.h
index 504818c..dbeb61e 100644
--- a/src/ss7_as.h
+++ b/src/ss7_as.h
@@ -17,6 +17,7 @@
struct osmo_ss7_instance;
struct osmo_ss7_asp;
+struct osmo_mtp_transfer_param;
enum osmo_ss7_as_patch_sccp_mode {
OSMO_SS7_PATCH_NONE, /* no patching of SCCP */
@@ -28,6 +29,15 @@
SS7_AS_CTR_TX_MSU_TOTAL,
};
+#define NUM_AS_EXT_SLS 128
+typedef uint8_t as_ext_sls_t; /* range: 0-127, 7 bit */
+struct osmo_ss7_as_esls_entry {
+ /* ITU Q.704 4.2.1: "normal signallink link" */
+ struct osmo_ss7_asp *normal_asp;
+ /* ITU Q.704 4.2.1: "alternative signallink link" */
+ struct osmo_ss7_asp *alt_asp;
+};
+
struct osmo_ss7_as {
/*! entry in 'ref osmo_ss7_instance.as_list */
struct llist_head list;
@@ -45,6 +55,9 @@
/*! Rate Counter Group */
struct rate_ctr_group *ctrg;
+ /* ASP loadshare: */
+ struct osmo_ss7_as_esls_entry aesls_table[NUM_AS_EXT_SLS];
+
struct {
char *name;
char *description;
@@ -64,8 +77,23 @@
struct osmo_ss7_asp *asps[16];
uint8_t last_asp_idx_sent; /* used for load-sharing traffic mode (round robin implementation) */
+
+ struct {
+ /* How many bits from ITU SLS field (starting from least-significant-bit)
+ * to skip for routing decisions.
+ * range 0-3, defaults to 0, which means take all 4 bits. */
+ uint8_t sls_shift;
+ /* Whether to generate a extended-SLS with OPC information, see opc_shift below. */
+ bool opc_sls;
+ /* How many bits from ITU OPC field (starting from least-significant-bit)
+ * to skip for routing decisions (always takes 12 bits).
+ * range 0-2, defaults to 0, which means take least significant 12 bits. */
+ uint8_t opc_shift;
+ } loadshare;
} cfg;
};
+struct osmo_ss7_asp *ss7_as_select_asp(struct osmo_ss7_as *as, const struct osmo_mtp_transfer_param *mtp);
+
#define LOGPAS(as, subsys, level, fmt, args ...) \
_LOGSS7((as)->inst, subsys, level, "as-%s: " fmt, (as)->cfg.name, ## args)
diff --git a/src/xua_as_fsm.c b/src/xua_as_fsm.c
index 5c2c5e0..e435970 100644
--- a/src/xua_as_fsm.c
+++ b/src/xua_as_fsm.c
@@ -150,7 +150,7 @@
* strictly required by M3UA RFC, but would fit the overall
* principle. */
case OSMO_SS7_AS_TMOD_ROUNDROBIN:
- asp = osmo_ss7_as_select_asp(as);
+ asp = ss7_as_select_asp(as, &xua->mtp);
break;
case OSMO_SS7_AS_TMOD_BCAST:
return xua_as_transmit_msg_broadcast(as, xua);
diff --git a/tests/vty/osmo_stp_test.vty b/tests/vty/osmo_stp_test.vty
index cb24560..dcde514 100644
--- a/tests/vty/osmo_stp_test.vty
+++ b/tests/vty/osmo_stp_test.vty
@@ -344,8 +344,10 @@
description .TEXT
asp NAME
no asp NAME
- traffic-mode (broadcast | loadshare | roundrobin | override)
+ traffic-mode (broadcast | roundrobin | override)
+ traffic-mode loadshare [bindings] [sls] [opc-sls] [opc-shift] [<0-2>]
no traffic-mode
+ sls-shift <0-3>
recovery-timeout <1-2000>
qos-class <0-7>
routing-key RCONTEXT DPC
@@ -361,6 +363,7 @@
asp Specify that a given ASP is part of this AS
no Negate a command or set its defaults
traffic-mode Specifies traffic mode of operation of the ASP within the AS
+ sls-shift Shift SLS bits used during routing decision
recovery-timeout Specifies the recovery timeout value in milliseconds
qos-class Specity QoS Class of AS
routing-key Define a routing key
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