gbproxy: Refactor IMSI matching

The current implementation makes it difficult to add further match
expressions.

This patch adds a new struct gbproxy_match that contains the fields
needed for each match expression. The matches (config) and the
results (link_info) are stored in arrays. All related functions are
updated to use them. The old fields in the config structure are
removed.

Sponsored-by: On-Waves ehf

4 files changed, 58 insertions, 35 deletions

diff --git a/openbsc/src/gprs/gb_proxy.c b/openbsc/src/gprs/gb_proxy.c
index 3257f7490..41ff4a785 100644
--- a/openbsc/src/gprs/gb_proxy.c
+++ b/openbsc/src/gprs/gb_proxy.c
@@ -584,7 +584,8 @@ static int gbprox_process_bssgp_ul(struct gbproxy_config *cfg,
 	if (link_info && cfg->route_to_sgsn2) {
 		if (cfg->acquire_imsi && link_info->imsi_len == 0)
 			sgsn_nsei = 0xffff;
-		else if (gbproxy_imsi_matches(peer, link_info))
+		else if (gbproxy_imsi_matches(cfg, GBPROX_MATCH_PATCHING,
+					      link_info))
 			sgsn_nsei = cfg->nsip_sgsn2_nsei;
 	}
 
@@ -1346,10 +1347,12 @@ void gbprox_reset(struct gbproxy_config *cfg)
 int gbproxy_init_config(struct gbproxy_config *cfg)
 {
 	struct timespec tp;
+
 	INIT_LLIST_HEAD(&cfg->bts_peers);
 	cfg->ctrg = rate_ctr_group_alloc(tall_bsc_ctx, &global_ctrg_desc, 0);
 	clock_gettime(CLOCK_REALTIME, &tp);
 	cfg->bss_ptmsi_state = tp.tv_sec + tp.tv_nsec;
 	cfg->sgsn_tlli_state = tp.tv_sec - tp.tv_nsec;
+
 	return 0;
 }
diff --git a/openbsc/src/gprs/gb_proxy_patch.c b/openbsc/src/gprs/gb_proxy_patch.c
index cf6eb8887..5cac8a5d8 100644
--- a/openbsc/src/gprs/gb_proxy_patch.c
+++ b/openbsc/src/gprs/gb_proxy_patch.c
@@ -24,6 +24,7 @@
 #include <openbsc/gprs_gb_parse.h>
 
 #include <openbsc/gsm_04_08_gprs.h>
+#include <openbsc/gsm_data.h>
 #include <openbsc/debug.h>
 
 #include <osmocom/gprs/protocol/gsm_08_18.h>
@@ -198,6 +199,7 @@ int gbproxy_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
 	struct gprs_llc_hdr_parsed *ghp = &parse_ctx->llc_hdr_parsed;
 	int have_patched = 0;
 	int fcs;
+	struct gbproxy_config *cfg = peer->cfg;
 
 	if (parse_ctx->ptmsi_enc && link_info &&
 	    !parse_ctx->old_raid_is_foreign && peer->cfg->patch_ptmsi) {
@@ -216,7 +218,7 @@ int gbproxy_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
 		}
 	}
 
-	if (parse_ctx->new_ptmsi_enc && link_info && peer->cfg->patch_ptmsi) {
+	if (parse_ctx->new_ptmsi_enc && link_info && cfg->patch_ptmsi) {
 		uint32_t ptmsi;
 		if (parse_ctx->to_bss)
 			ptmsi = link_info->tlli.ptmsi;
@@ -243,9 +245,10 @@ int gbproxy_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
 	}
 
 	if (parse_ctx->apn_ie &&
-	    peer->cfg->core_apn &&
+	    cfg->core_apn &&
 	    !parse_ctx->to_bss &&
-	    gbproxy_imsi_matches(peer, link_info) && peer->cfg->core_apn) {
+	    gbproxy_imsi_matches(cfg, GBPROX_MATCH_PATCHING, link_info) &&
+	    cfg->core_apn) {
 		size_t new_len;
 		gbproxy_patch_apn_ie(msg,
 				     parse_ctx->apn_ie, parse_ctx->apn_ie_len,
@@ -371,35 +374,38 @@ patch_error:
 	     err_info);
 }
 
-void gbproxy_clear_patch_filter(struct gbproxy_config *cfg)
+void gbproxy_clear_patch_filter(struct gbproxy_match *match)
 {
-	if (cfg->check_imsi) {
-		regfree(&cfg->imsi_re_comp);
-		cfg->check_imsi = 0;
+	if (match->enable) {
+		regfree(&match->re_comp);
+		match->enable = 0;
 	}
+	talloc_free(match->re_str);
+	match->re_str = NULL;
 }
 
-int gbproxy_set_patch_filter(struct gbproxy_config *cfg, const char *filter,
+int gbproxy_set_patch_filter(struct gbproxy_match *match, const char *filter,
 		const char **err_msg)
 {
 	static char err_buf[300];
 	int rc;
 
-	gbproxy_clear_patch_filter(cfg);
+	gbproxy_clear_patch_filter(match);
 
 	if (!filter)
 		return 0;
 
-	rc = regcomp(&cfg->imsi_re_comp, filter,
+	rc = regcomp(&match->re_comp, filter,
 		     REG_EXTENDED | REG_NOSUB | REG_ICASE);
 
 	if (rc == 0) {
-		cfg->check_imsi = 1;
+		match->enable = 1;
+		match->re_str = talloc_strdup(tall_bsc_ctx, filter);
 		return 0;
 	}
 
 	if (err_msg) {
-		regerror(rc, &cfg->imsi_re_comp,
+		regerror(rc, &match->re_comp,
 			 err_buf, sizeof(err_buf));
 		*err_msg = err_buf;
 	}
@@ -407,13 +413,13 @@ int gbproxy_set_patch_filter(struct gbproxy_config *cfg, const char *filter,
 	return -1;
 }
 
-int gbproxy_check_imsi(struct gbproxy_peer *peer,
+int gbproxy_check_imsi(struct gbproxy_match *match,
 		       const uint8_t *imsi, size_t imsi_len)
 {
 	char mi_buf[200];
 	int rc;
 
-	if (!peer->cfg->check_imsi)
+	if (!match->enable)
 		return 1;
 
 	rc = gprs_is_mi_imsi(imsi, imsi_len);
@@ -427,11 +433,11 @@ int gbproxy_check_imsi(struct gbproxy_peer *peer,
 
 	LOGP(DGPRS, LOGL_DEBUG, "Checking IMSI '%s' (%d)\n", mi_buf, rc);
 
-	rc = regexec(&peer->cfg->imsi_re_comp, mi_buf, 0, NULL, 0);
+	rc = regexec(&match->re_comp, mi_buf, 0, NULL, 0);
 	if (rc == REG_NOMATCH) {
 		LOGP(DGPRS, LOGL_INFO,
 		       "IMSI '%s' doesn't match pattern '%s'\n",
-		       mi_buf, peer->cfg->match_re);
+		       mi_buf, match->re_str);
 		return 0;
 	}
 
diff --git a/openbsc/src/gprs/gb_proxy_tlli.c b/openbsc/src/gprs/gb_proxy_tlli.c
index 093d2b328..d521434da 100644
--- a/openbsc/src/gprs/gb_proxy_tlli.c
+++ b/openbsc/src/gprs/gb_proxy_tlli.c
@@ -374,13 +374,18 @@ static void gbproxy_unregister_link_info(struct gbproxy_peer *peer,
 	return;
 }
 
-int gbproxy_imsi_matches(struct gbproxy_peer *peer,
-		       struct gbproxy_link_info *link_info)
+int gbproxy_imsi_matches(struct gbproxy_config *cfg,
+			 enum gbproxy_match_id match_id,
+			 struct gbproxy_link_info *link_info)
 {
-	if (!peer->cfg->check_imsi)
+	struct gbproxy_match *match;
+	OSMO_ASSERT(match_id >= 0 && match_id < ARRAY_SIZE(cfg->matches));
+
+	match = &cfg->matches[match_id];
+	if (!match->enable)
 		return 1;
 
-	return link_info != NULL && link_info->imsi_matches;
+	return link_info != NULL && link_info->is_matching[match_id];
 }
 
 void gbproxy_assign_imsi(struct gbproxy_peer *peer,
@@ -389,6 +394,7 @@ void gbproxy_assign_imsi(struct gbproxy_peer *peer,
 {
 	int imsi_matches;
 	struct gbproxy_link_info *other_link_info;
+	enum gbproxy_match_id match_id;
 
 	/* Make sure that there is a second entry with the same IMSI */
 	other_link_info = gbproxy_link_info_by_imsi(
@@ -410,10 +416,16 @@ void gbproxy_assign_imsi(struct gbproxy_peer *peer,
 				 parse_ctx->imsi, parse_ctx->imsi_len);
 
 	/* Check, whether the IMSI matches */
-	imsi_matches = gbproxy_check_imsi(peer, parse_ctx->imsi,
-					     parse_ctx->imsi_len);
-	if (imsi_matches >= 0)
-		link_info->imsi_matches = imsi_matches;
+	OSMO_ASSERT(ARRAY_SIZE(link_info->is_matching) ==
+		    ARRAY_SIZE(peer->cfg->matches));
+	for (match_id = 0; match_id < ARRAY_SIZE(link_info->is_matching);
+	     ++match_id) {
+		imsi_matches = gbproxy_check_imsi(
+			&peer->cfg->matches[match_id],
+			parse_ctx->imsi, parse_ctx->imsi_len);
+		if (imsi_matches >= 0)
+			link_info->is_matching[match_id] = imsi_matches;
+	}
 }
 
 static int gbproxy_tlli_match(const struct gbproxy_tlli_state *a,
diff --git a/openbsc/src/gprs/gb_proxy_vty.c b/openbsc/src/gprs/gb_proxy_vty.c
index 82d7d9541..6dc0e3437 100644
--- a/openbsc/src/gprs/gb_proxy_vty.c
+++ b/openbsc/src/gprs/gb_proxy_vty.c
@@ -75,6 +75,8 @@ static void gbprox_vty_print_peer(struct vty *vty, struct gbproxy_peer *peer)
 
 static int config_write_gbproxy(struct vty *vty)
 {
+	enum gbproxy_match_id match_id;
+
 	vty_out(vty, "gbproxy%s", VTY_NEWLINE);
 
 	vty_out(vty, " sgsn nsei %u%s", g_cfg->nsip_sgsn_nsei,
@@ -87,9 +89,12 @@ static int config_write_gbproxy(struct vty *vty)
 		vty_out(vty, " core-mobile-network-code %d%s",
 			g_cfg->core_mnc, VTY_NEWLINE);
 
-	if (g_cfg->match_re)
-		vty_out(vty, " match-imsi %s%s",
-			g_cfg->match_re, VTY_NEWLINE);
+	for (match_id = 0; match_id < ARRAY_SIZE(g_cfg->matches); ++match_id) {
+		struct gbproxy_match *match = &g_cfg->matches[match_id];
+		if (match->re_str)
+			vty_out(vty, " match-imsi %s%s",
+				match->re_str, VTY_NEWLINE);
+	}
 
 	if (g_cfg->core_apn != NULL) {
 	       if (g_cfg->core_apn_size > 0) {
@@ -194,15 +199,13 @@ DEFUN(cfg_gbproxy_match_imsi,
 {
 	const char *filter = argv[0];
 	const char *err_msg = NULL;
+	struct gbproxy_match *match = &g_cfg->matches[GBPROX_MATCH_PATCHING];
 
-	if (gbproxy_set_patch_filter(g_cfg, filter, &err_msg) != 0) {
+	if (gbproxy_set_patch_filter(match, filter, &err_msg) != 0) {
 		vty_out(vty, "Match expression invalid: %s%s",
 			err_msg, VTY_NEWLINE);
 		return CMD_WARNING;
 	}
-	talloc_free(g_cfg->match_re);
-	/* TODO: replace NULL */
-	g_cfg->match_re = talloc_strdup(NULL, filter);
 
 	g_cfg->acquire_imsi = 1;
 
@@ -214,10 +217,9 @@ DEFUN(cfg_gbproxy_no_match_imsi,
       "no match-imsi",
       NO_STR GBPROXY_MATCH_IMSI_STR)
 {
-	gbproxy_clear_patch_filter(g_cfg);
+	struct gbproxy_match *match = &g_cfg->matches[GBPROX_MATCH_PATCHING];
 
-	talloc_free(g_cfg->match_re);
-	g_cfg->match_re = NULL;
+	gbproxy_clear_patch_filter(match);
 
 	g_cfg->acquire_imsi = 0;