iu_helpers: add function ranap_transp_layer_addr_decode2

Add ranap_transp_layer_addr_decode2 as AF agnostic version of
ranap_transp_layer_addr_decode.

Change-Id: Ia60e0ab671fc4185815a880377ab88fcf1b30ac9

4 files changed, 122 insertions, 0 deletions

diff --git a/include/osmocom/ranap/iu_helpers.h b/include/osmocom/ranap/iu_helpers.h
index d824646..bf2a580 100644
--- a/include/osmocom/ranap/iu_helpers.h
+++ b/include/osmocom/ranap/iu_helpers.h
@@ -15,6 +15,8 @@ int ranap_imsi_encode(uint8_t *out, size_t out_len, const char *in);
 int ranap_transp_assoc_decode(uint16_t *port, const RANAP_IuTransportAssociation_t *transp_assoc);
 int ranap_transp_layer_addr_decode(char *addr, unsigned int addr_len,
 				   const RANAP_TransportLayerAddress_t *trasp_layer_addr);
+int ranap_transp_layer_addr_decode2(struct osmo_sockaddr *addr, bool *uses_x213_nsap,
+				    const RANAP_TransportLayerAddress_t *trasp_layer_addr);
 RANAP_TransportLayerInformation_t *ranap_new_transp_info_rtp(struct osmo_sockaddr *addr, bool use_x213_nsap);
 RANAP_TransportLayerInformation_t *ranap_new_transp_info_gtp(struct osmo_sockaddr *addr, uint32_t tei,
 							     bool use_x213_nsap);
diff --git a/src/iu_helpers.c b/src/iu_helpers.c
index 62f5c22..1591f7d 100644
--- a/src/iu_helpers.c
+++ b/src/iu_helpers.c
@@ -126,6 +126,56 @@ int ranap_transp_layer_addr_decode(char *addr, unsigned int addr_len,
 	return 0;
 }
 
+/* (same as ranap_transp_layer_addr_decode, but AF agnostic) */
+int ranap_transp_layer_addr_decode2(struct osmo_sockaddr *addr, bool *uses_x213_nsap,
+				    const RANAP_TransportLayerAddress_t *trasp_layer_addr)
+{
+	unsigned char *buf;
+	int len;
+	bool x213_nsap = false;
+	uint16_t icp;
+
+	buf = trasp_layer_addr->buf;
+	len = trasp_layer_addr->size;
+
+	memset(addr, 0, sizeof(*addr));
+
+	if (len == 20 && buf[0] == 0x35) {
+		/* For an X.213 NSAP encoded address we expect a buffer of exactly 20 bytes (3 bytes IDP + 17 bytes
+		 * DSP). we also expect AFI = 0x35, which means that two byte IDI and an IP address follows. (see also
+		 * comments in function new_transp_layer_addr below) */
+		x213_nsap = true;
+		icp = osmo_load16be(&buf[1]);
+		switch (icp) {
+		case 0x0000:
+			addr->u.sa.sa_family = AF_INET6;
+			memcpy(addr->u.sin6.sin6_addr.s6_addr, buf + 3, sizeof(addr->u.sin6.sin6_addr.s6_addr));
+			break;
+		case 0x0001:
+			addr->u.sa.sa_family = AF_INET;
+			memcpy((uint8_t *) &addr->u.sin.sin_addr.s_addr, buf + 3, sizeof(addr->u.sin.sin_addr.s_addr));
+			break;
+		default:
+			return -EINVAL;
+		}
+	} else if (len == 4) {
+		/* A non X.213 NSAP encoded IPv4 address is 4 bytes long */
+		addr->u.sa.sa_family = AF_INET;
+		memcpy((uint8_t *) &addr->u.sin.sin_addr.s_addr, buf, sizeof(addr->u.sin.sin_addr.s_addr));
+	} else if (len == 16) {
+		/* A non X.213 NSAP encoded IPv6 address is 16 bytes long */
+		addr->u.sa.sa_family = AF_INET6;
+		memcpy(addr->u.sin6.sin6_addr.s6_addr, buf, sizeof(addr->u.sin6.sin6_addr.s6_addr));
+	} else
+		return -EINVAL;
+
+	/* In case the caller is interested in the encoding method that was used */
+	if (uses_x213_nsap)
+		*uses_x213_nsap = x213_nsap;
+
+	return 0;
+}
+
 static int new_transp_layer_addr(BIT_STRING_t *out, struct osmo_sockaddr *addr, bool use_x213_nsap)
 {
 	uint8_t *buf;
diff --git a/src/tests/test-helpers.c b/src/tests/test-helpers.c
index 5b5004a..42e8b26 100644
--- a/src/tests/test-helpers.c
+++ b/src/tests/test-helpers.c
@@ -29,6 +29,7 @@
 
 #include <osmocom/core/utils.h>
 #include <osmocom/core/socket.h>
+#include <osmocom/core/sockaddr_str.h>
 #include <osmocom/gsm/gsm48.h>
 
 #include <osmocom/ranap/RANAP_LAI.h>
@@ -347,6 +348,65 @@ void test_ranap_transp_layer_addr_decode(void)
 	OSMO_ASSERT(rc == 0);
 }
 
+void test_ranap_transp_layer_addr_decode2(void)
+{
+	int rc;
+	struct osmo_sockaddr addr;
+	struct osmo_sockaddr_str sockaddr_str;
+	bool uses_x213_nsap;
+	RANAP_TransportLayerAddress_t trasp_layer_addr = { 0 };
+	uint8_t encoded_ipv4_addr_x213_nsap[] = {
+		0x35, 0x00, 0x01, 0x01, 0x02, 0x03, 0x04, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00 };
+	uint8_t encoded_ipv4_addr[] = { 0x01, 0x02, 0x03, 0x04 };
+	uint8_t encoded_ipv6_addr_x213_nsap[] =	{
+		0x35, 0x00, 0x00, 0xf1, 0x1f, 0xf2, 0x2f, 0xf3,
+		0x3f, 0xf4, 0x4f, 0xf5, 0x5f, 0xf6, 0x6f, 0xf7,
+		0x7f, 0xf8, 0x8f, 0x00 };
+	uint8_t encoded_ipv6_addr[] = {
+		0xf1, 0x1f, 0xf2, 0x2f, 0xf3, 0x3f, 0xf4, 0x4f,
+		0xf5, 0x5f, 0xf6, 0x6f, 0xf7, 0x7f, 0xf8, 0x8f };
+
+	printf("Testing function ranap_transp_layer_addr_decode2()\n");
+
+	printf(" ipv4, x213_nsap\n");
+	trasp_layer_addr.buf = encoded_ipv4_addr_x213_nsap;
+	trasp_layer_addr.size = sizeof(encoded_ipv4_addr_x213_nsap);
+	rc = ranap_transp_layer_addr_decode2(&addr, &uses_x213_nsap, &trasp_layer_addr);
+	OSMO_ASSERT(rc == 0);
+	memset(&sockaddr_str, 0, sizeof(sockaddr_str));
+	osmo_sockaddr_str_from_sockaddr_in(&sockaddr_str, &addr.u.sin);
+	printf("  addr=%s, af=%d, x213_nsap=%u\n", sockaddr_str.ip, sockaddr_str.af, uses_x213_nsap);
+
+	printf(" ipv4\n");
+	trasp_layer_addr.buf = encoded_ipv4_addr;
+	trasp_layer_addr.size = sizeof(encoded_ipv4_addr);
+	rc = ranap_transp_layer_addr_decode2(&addr, &uses_x213_nsap, &trasp_layer_addr);
+	OSMO_ASSERT(rc == 0);
+	memset(&sockaddr_str, 0, sizeof(sockaddr_str));
+	osmo_sockaddr_str_from_sockaddr_in(&sockaddr_str, &addr.u.sin);
+	printf("  addr=%s, af=%d, x213_nsap=%u\n", sockaddr_str.ip, sockaddr_str.af, uses_x213_nsap);
+
+	printf(" ipv6, x213_nsap\n");
+	trasp_layer_addr.buf = encoded_ipv6_addr_x213_nsap;
+	trasp_layer_addr.size = sizeof(encoded_ipv6_addr_x213_nsap);
+	rc = ranap_transp_layer_addr_decode2(&addr, &uses_x213_nsap, &trasp_layer_addr);
+	OSMO_ASSERT(rc == 0);
+	memset(&sockaddr_str, 0, sizeof(sockaddr_str));
+	osmo_sockaddr_str_from_sockaddr_in6(&sockaddr_str, &addr.u.sin6);
+	printf("  addr=%s, af=%d, x213_nsap=%u\n", sockaddr_str.ip, sockaddr_str.af, uses_x213_nsap);
+
+	printf(" ipv6\n");
+	trasp_layer_addr.buf = encoded_ipv6_addr;
+	trasp_layer_addr.size = sizeof(encoded_ipv6_addr);
+	rc = ranap_transp_layer_addr_decode2(&addr, &uses_x213_nsap, &trasp_layer_addr);
+	OSMO_ASSERT(rc == 0);
+	memset(&sockaddr_str, 0, sizeof(sockaddr_str));
+	osmo_sockaddr_str_from_sockaddr_in6(&sockaddr_str, &addr.u.sin6);
+	printf("  addr=%s, af=%d, x213_nsap=%u\n", sockaddr_str.ip, sockaddr_str.af, uses_x213_nsap);
+}
+
 int main(int argc, char **argv)
 {
 	asn1_xer_print = 0;
@@ -360,6 +420,7 @@ int main(int argc, char **argv)
 	test_ranap_new_transp_info_gtp();
 	test_ranap_new_transp_info_rtp();
 	test_ranap_transp_layer_addr_decode();
+	test_ranap_transp_layer_addr_decode2();
 
 	test_common_cleanup();
 	return 0;
diff --git a/src/tests/test-helpers.ok b/src/tests/test-helpers.ok
index fe08287..0626413 100644
--- a/src/tests/test-helpers.ok
+++ b/src/tests/test-helpers.ok
@@ -56,3 +56,12 @@ Testing function ranap_transp_layer_addr_decode()
   addr=1.2.3.4
  ipv4
   addr=1.2.3.4
+Testing function ranap_transp_layer_addr_decode2()
+ ipv4, x213_nsap
+  addr=1.2.3.4, af=2, x213_nsap=1
+ ipv4
+  addr=1.2.3.4, af=2, x213_nsap=0
+ ipv6, x213_nsap
+  addr=f11f:f22f:f33f:f44f:f55f:f66f:f77f:f88f, af=10, x213_nsap=1
+ ipv6
+  addr=f11f:f22f:f33f:f44f:f55f:f66f:f77f:f88f, af=10, x213_nsap=0