Add a GSM RLP decoder and encoder
This code implements a decoder and encoder for the RLP (Radio Link
Protocol) as used in the bearer channel of GSM CSD (Circuit Switched
Data).
Change-Id: I2d9bd8eb4f0cd0f72c436996767b199429596917
diff --git a/tests/rlp/rlp_test.c b/tests/rlp/rlp_test.c
new file mode 100644
index 0000000..be26c99
--- /dev/null
+++ b/tests/rlp/rlp_test.c
@@ -0,0 +1,217 @@
+#include <osmocom/core/utils.h>
+#include <osmocom/gsm/rlp.h>
+
+struct rlp_testcase {
+ const char *name;
+ const char *encoded_hex;
+ struct osmo_rlp_frame_decoded decoded;
+};
+
+
+const struct rlp_testcase testcases[] = {
+ {
+ .name = "XID1",
+ .encoded_hex = "f95f1100213d313d414e6108510600000000000000000000000000c13c6b",
+ .decoded = {
+ .version = 0,
+ .ftype = OSMO_RLP_FT_U,
+ .u_ftype = OSMO_RLP_U_FT_XID,
+ .s_ftype = 0,
+ .c_r = 1,
+ .p_f = 1,
+ .s_bits = 0,
+ .n_s = 0,
+ .n_r = 0,
+ .fcs = 0x6b3cc1,
+ .info = { 0x11, 0x00, 0x21, 0x3d, 0x31, 0x3d, 0x41, 0x4e, 0x61, 0x08,
+ 0x51, 0x06, },
+ .info_len = 25,
+ },
+ }, {
+ .name = "XID2",
+ .encoded_hex = "f95f1101213d313d41305106610774000008060000000000000000ba14a0",
+ .decoded = {
+ .version = 0,
+ .ftype = OSMO_RLP_FT_U,
+ .u_ftype = OSMO_RLP_U_FT_XID,
+ .s_ftype = 0,
+ .c_r = 1,
+ .p_f = 1,
+ .s_bits = 0,
+ .n_s = 0,
+ .n_r = 0,
+ .fcs = 0xa014ba,
+ .info = { 0x11, 0x01, 0x21, 0x3d, 0x31, 0x3d, 0x41, 0x30, 0x51, 0x06,
+ 0x61, 0x07, 0x74, 0x00, 0x00, 0x08, 0x06, },
+ .info_len = 25,
+ },
+ }, {
+ .name = "SABM",
+ .encoded_hex = "f91f0000000000000000000000000000000000000000000000000063b2f3",
+ .decoded = {
+ .version = 0,
+ .ftype = OSMO_RLP_FT_U,
+ .u_ftype = OSMO_RLP_U_FT_SABM,
+ .s_ftype = 0,
+ .c_r = 1,
+ .p_f = 1,
+ .s_bits = 0,
+ .n_s = 0,
+ .n_r = 0,
+ .fcs = 0xf3b263,
+ .info = {},
+ .info_len = 0,
+ },
+ }, {
+ .name = "UA",
+ .encoded_hex = "f8330000000000000000000000000000000000000000000000000029d801",
+ .decoded = {
+ .version = 0,
+ .ftype = OSMO_RLP_FT_U,
+ .u_ftype = OSMO_RLP_U_FT_UA,
+ .s_ftype = 0,
+ .c_r = 0,
+ .p_f = 1,
+ .s_bits = 0,
+ .n_s = 0,
+ .n_r = 0,
+ .fcs = 0x01d829,
+ .info = {},
+ .info_len = 0,
+ },
+ }, {
+ .name = "IS1",
+ .encoded_hex = "01001f000000000000000000000000000000000000000000000000f174ad",
+ .decoded = {
+ .version = 0,
+ .ftype = OSMO_RLP_FT_IS,
+ .u_ftype = 0,
+ .s_ftype = 0,
+ .c_r = 1,
+ .p_f = 0,
+ .s_bits = 0,
+ .n_s = 0,
+ .n_r = 0,
+ .fcs = 0xad74f1,
+ .info = { 0x1f, },
+ .info_len = 25,
+ },
+ }, {
+ .name = "IS2",
+ .encoded_hex = "010401661fffffffffffffffffffffffffffffffffffffffffffff388cd3",
+ .decoded = {
+ .version = 0,
+ .ftype = OSMO_RLP_FT_IS,
+ .u_ftype = 0,
+ .s_ftype = 0,
+ .c_r = 1,
+ .p_f = 0,
+ .s_bits = 0,
+ .n_s = 0,
+ .n_r = 1,
+ .fcs = 0xd38c38,
+ .info = { 0x01, 0x66, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff },
+ .info_len = 25,
+ },
+ }, {
+ .name = "DISC",
+ .encoded_hex = "f923000000000000000000000000000000000000000000000000007986f2",
+ .decoded = {
+ .version = 0,
+ .ftype = OSMO_RLP_FT_U,
+ .u_ftype = OSMO_RLP_U_FT_DISC,
+ .s_ftype = 0,
+ .c_r = 1,
+ .p_f = 1,
+ .s_bits = 0,
+ .n_s = 0,
+ .n_r = 0,
+ .fcs = 0xf28679,
+ .info = { },
+ .info_len = 0,
+ },
+ }
+};
+
+static void rlp_frame_print_u(const struct osmo_rlp_frame_decoded *rf)
+{
+ OSMO_ASSERT(rf->ftype == OSMO_RLP_FT_U);
+ printf("C/R=%u P/F=%u U %s (FCS=0x%06x) %s\n", rf->c_r, rf->p_f,
+ get_value_string(osmo_rlp_ftype_u_vals, rf->u_ftype),
+ rf->fcs,
+ rf->u_ftype == OSMO_RLP_U_FT_XID ? osmo_hexdump_nospc(rf->info, rf->info_len) : "");
+}
+
+static void rlp_frame_print_s(const struct osmo_rlp_frame_decoded *rf)
+{
+ OSMO_ASSERT(rf->ftype == OSMO_RLP_FT_S);
+ printf("C/R=%u P/F=%u S N(R)=%u %s (FCS=0x%06x)\n", rf->c_r, rf->p_f,
+ rf->n_r, get_value_string(osmo_rlp_ftype_s_vals, rf->s_ftype),
+ rf->fcs);
+}
+
+static void rlp_frame_print_is(const struct osmo_rlp_frame_decoded *rf)
+{
+ OSMO_ASSERT(rf->ftype == OSMO_RLP_FT_IS);
+ printf("C/R=%u P/F=%u IS N(R)=%u N(S)=%u %s (FCS=0x%06x) %s\n", rf->c_r, rf->p_f,
+ rf->n_r, rf->n_s, get_value_string(osmo_rlp_ftype_s_vals, rf->s_ftype),
+ rf->fcs, osmo_hexdump_nospc(rf->info, rf->info_len));
+}
+
+static void rlp_frame_print(const struct osmo_rlp_frame_decoded *rf)
+{
+ switch (rf->ftype) {
+ case OSMO_RLP_FT_U:
+ rlp_frame_print_u(rf);
+ break;
+ case OSMO_RLP_FT_S:
+ rlp_frame_print_s(rf);
+ break;
+ case OSMO_RLP_FT_IS:
+ rlp_frame_print_is(rf);
+ break;
+ default:
+ OSMO_ASSERT(0);
+ }
+}
+
+static void execute_rlp_test(const struct rlp_testcase *tc)
+{
+ struct osmo_rlp_frame_decoded decoded;
+ uint8_t inbuf[240/8];
+ int rc;
+
+ printf("=== STARTING TESTCASE '%s'\n", tc->name);
+
+ rc = osmo_hexparse(tc->encoded_hex, inbuf, sizeof(inbuf));
+ OSMO_ASSERT(rc == 240/8);
+
+ printf("Decoding %s:\n", tc->encoded_hex);
+ rc = osmo_rlp_decode(&decoded, 0, inbuf, rc);
+ OSMO_ASSERT(rc == 0);
+
+ printf("Comparing...\n");
+ rlp_frame_print(&decoded);
+ if (memcmp(&decoded, &tc->decoded, sizeof(decoded))) {
+ printf("DOESN'T MATCH EXPECTED DECODE:\n");
+ rlp_frame_print(&tc->decoded);
+ }
+
+ printf("Reencoding...\n");
+ uint8_t reencoded[240/8];
+ rc = osmo_rlp_encode(reencoded, sizeof(reencoded), &tc->decoded);
+ OSMO_ASSERT(rc == 240/8);
+ if (memcmp(inbuf, reencoded, sizeof(inbuf)))
+ printf("DOESN'T MATCH EXPECTED ENCODE FROM ABOVE\n");
+}
+
+int main(int argc, char **argv)
+{
+ for (unsigned int i = 0; i < ARRAY_SIZE(testcases); i++) {
+ const struct rlp_testcase *tc = &testcases[i];
+ execute_rlp_test(tc);
+ }
+
+}