move openbsc/* to repos root

This is the first step in creating this repository from the legacy openbsc.git.

Like all other Osmocom repositories, keep the autoconf and automake files in
the repository root. openbsc.git has been the sole exception, which ends now.

Change-Id: I9c6f2a448d9cb1cc088cf1cf6918b69d7e69b4e7

1 files changed, 282 insertions, 0 deletions

diff --git a/src/gprs/gprs_sndcp_pcomp.c b/src/gprs/gprs_sndcp_pcomp.c
new file mode 100644
index 000000000..a2236c3b1
--- /dev/null
+++ b/src/gprs/gprs_sndcp_pcomp.c
@@ -0,0 +1,282 @@
+/* GPRS SNDCP header compression handler */
+
+/* (C) 2016 by Sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <math.h>
+#include <errno.h>
+#include <stdbool.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/gsm/tlv.h>
+
+#include <openbsc/gprs_llc.h>
+#include <openbsc/sgsn.h>
+#include <openbsc/gprs_sndcp_xid.h>
+#include <openbsc/slhc.h>
+#include <openbsc/debug.h>
+#include <openbsc/gprs_sndcp_comp.h>
+#include <openbsc/gprs_sndcp_pcomp.h>
+
+/* Initalize header compression */
+int gprs_sndcp_pcomp_init(const void *ctx, struct gprs_sndcp_comp *comp_entity,
+			  const struct gprs_sndcp_comp_field *comp_field)
+{
+	/* Note: This function is automatically called from
+	 * gprs_sndcp_comp.c when a new header compression
+	 * entity is created by gprs_sndcp.c */
+
+	OSMO_ASSERT(comp_entity);
+	OSMO_ASSERT(comp_field);
+
+	if (comp_entity->compclass == SNDCP_XID_PROTOCOL_COMPRESSION
+	    && comp_entity->algo == RFC_1144) {
+		OSMO_ASSERT(comp_field->rfc1144_params);
+		comp_entity->state =
+		    slhc_init(ctx, comp_field->rfc1144_params->s01 + 1,
+			      comp_field->rfc1144_params->s01 + 1);
+		LOGP(DSNDCP, LOGL_INFO,
+		     "RFC1144 header compression initalized.\n");
+		return 0;
+	}
+
+	/* Just in case someone tries to initalize an unknown or unsupported
+	 * header compresson. Since everything is checked during the SNDCP
+	 * negotiation process, this should never happen! */
+	OSMO_ASSERT(false);
+}
+
+/* Terminate header compression */
+void gprs_sndcp_pcomp_term(struct gprs_sndcp_comp *comp_entity)
+{
+	/* Note: This function is automatically called from
+	 * gprs_sndcp_comp.c when a header compression
+	 * entity is deleted by gprs_sndcp.c */
+
+	OSMO_ASSERT(comp_entity);
+
+	if (comp_entity->compclass == SNDCP_XID_PROTOCOL_COMPRESSION
+	    && comp_entity->algo == RFC_1144) {
+		if (comp_entity->state) {
+			slhc_free((struct slcompress *)comp_entity->state);
+			comp_entity->state = NULL;
+		}
+		LOGP(DSNDCP, LOGL_INFO,
+		     "RFC1144 header compression terminated.\n");
+		return;
+	}
+
+	/* Just in case someone tries to terminate an unknown or unsupported
+	 * data compresson. Since everything is checked during the SNDCP
+	 * negotiation process, this should never happen! */
+	OSMO_ASSERT(false);
+}
+
+/* Compress a packet using Van Jacobson RFC1144 header compression */
+static int rfc1144_compress(uint8_t *pcomp_index, uint8_t *data,
+			    unsigned int len, struct slcompress *comp)
+{
+	uint8_t *comp_ptr;
+	int compr_len;
+	uint8_t *data_o;
+
+	/* Create a working copy of the incoming data */
+	data_o = talloc_zero_size(comp, len);
+	memcpy(data_o, data, len);
+
+	/* Run compressor */
+	compr_len = slhc_compress(comp, data, len, data_o, &comp_ptr, 0);
+
+	/* Generate pcomp_index */
+	if (data_o[0] & SL_TYPE_COMPRESSED_TCP) {
+		*pcomp_index = 2;
+		data_o[0] &= ~SL_TYPE_COMPRESSED_TCP;
+		memcpy(data, data_o, compr_len);
+	} else if ((data_o[0] & SL_TYPE_UNCOMPRESSED_TCP) ==
+		   SL_TYPE_UNCOMPRESSED_TCP) {
+		*pcomp_index = 1;
+		data_o[0] &= 0x4F;
+		memcpy(data, data_o, compr_len);
+	} else
+		*pcomp_index = 0;
+
+	talloc_free(data_o);
+	return compr_len;
+}
+
+/* Expand a packet using Van Jacobson RFC1144 header compression */
+static int rfc1144_expand(uint8_t *data, unsigned int len, uint8_t pcomp_index,
+			  struct slcompress *comp)
+{
+	int data_decompressed_len;
+	int type;
+
+	/* Note: this function should never be called with pcomp_index=0,
+	 * since this condition is already filtered
+	 * out by gprs_sndcp_pcomp_expand() */
+
+	/* Determine the data type by the PCOMP index */
+	switch (pcomp_index) {
+	case 0:
+		type = SL_TYPE_IP;
+		break;
+	case 1:
+		type = SL_TYPE_UNCOMPRESSED_TCP;
+		break;
+	case 2:
+		type = SL_TYPE_COMPRESSED_TCP;
+		break;
+	default:
+		LOGP(DSNDCP, LOGL_ERROR,
+		     "rfc1144_expand() Invalid pcomp_index value (%d) detected, assuming no compression!\n",
+		     pcomp_index);
+		type = SL_TYPE_IP;
+		break;
+	}
+
+	/* Restore the original version nibble on
+	 * marked uncompressed packets */
+	if (type == SL_TYPE_UNCOMPRESSED_TCP) {
+		/* Just in case the phone tags uncompressed tcp-data
+		 * (normally this is handled by pcomp so there is
+		 * no need for tagging the data) */
+		data[0] &= 0x4F;
+		data_decompressed_len = slhc_remember(comp, data, len);
+		return data_decompressed_len;
+	}
+
+	/* Uncompress compressed packets */
+	else if (type == SL_TYPE_COMPRESSED_TCP) {
+		data_decompressed_len = slhc_uncompress(comp, data, len);
+		return data_decompressed_len;
+	}
+
+	/* Regular or unknown packets will not be touched */
+	return len;
+}
+
+/* Expand packet header */
+int gprs_sndcp_pcomp_expand(uint8_t *data, unsigned int len, uint8_t pcomp,
+			    const struct llist_head *comp_entities)
+{
+	int rc;
+	uint8_t pcomp_index = 0;
+	struct gprs_sndcp_comp *comp_entity;
+
+	OSMO_ASSERT(data);
+	OSMO_ASSERT(comp_entities);
+
+	LOGP(DSNDCP, LOGL_DEBUG,
+	     "Header compression entity list: comp_entities=%p\n",
+	     comp_entities);
+
+	LOGP(DSNDCP, LOGL_DEBUG, "Header compression mode: pcomp=%d\n", pcomp);
+
+	/* Skip on pcomp=0 */
+	if (pcomp == 0) {
+		return len;
+	}
+
+	/* Find out which compression entity handles the data */
+	comp_entity = gprs_sndcp_comp_by_comp(comp_entities, pcomp);
+
+	/* Skip compression if no suitable compression entity can be found */
+	if (!comp_entity) {
+		return len;
+	}
+
+	/* Note: Only protocol compression entities may appear in
+	 * protocol compression context */
+	OSMO_ASSERT(comp_entity->compclass == SNDCP_XID_PROTOCOL_COMPRESSION);
+
+	/* Note: Currently RFC1144 is the only compression method we
+	 * support, so the only allowed algorithm is RFC1144 */
+	OSMO_ASSERT(comp_entity->algo == RFC_1144);
+
+	/* Find pcomp_index */
+	pcomp_index = gprs_sndcp_comp_get_idx(comp_entity, pcomp);
+
+	/* Run decompression algo */
+	rc = rfc1144_expand(data, len, pcomp_index, comp_entity->state);
+	slhc_i_status(comp_entity->state);
+	slhc_o_status(comp_entity->state);
+
+	LOGP(DSNDCP, LOGL_DEBUG,
+	     "Header expansion done, old length=%d, new length=%d, entity=%p\n",
+	     len, rc, comp_entity);
+
+	return rc;
+}
+
+/* Compress packet header */
+int gprs_sndcp_pcomp_compress(uint8_t *data, unsigned int len, uint8_t *pcomp,
+			      const struct llist_head *comp_entities,
+			      uint8_t nsapi)
+{
+	int rc;
+	uint8_t pcomp_index = 0;
+	struct gprs_sndcp_comp *comp_entity;
+
+	OSMO_ASSERT(data);
+	OSMO_ASSERT(pcomp);
+	OSMO_ASSERT(comp_entities);
+
+	LOGP(DSNDCP, LOGL_DEBUG,
+	     "Header compression entity list: comp_entities=%p\n",
+	     comp_entities);
+
+	/* Find out which compression entity handles the data */
+	comp_entity = gprs_sndcp_comp_by_nsapi(comp_entities, nsapi);
+
+	/* Skip compression if no suitable compression entity can be found */
+	if (!comp_entity) {
+		*pcomp = 0;
+		return len;
+	}
+
+	/* Note: Only protocol compression entities may appear in
+	 * protocol compression context */
+	OSMO_ASSERT(comp_entity->compclass == SNDCP_XID_PROTOCOL_COMPRESSION);
+
+	/* Note: Currently RFC1144 is the only compression method we
+	 * support, so the only allowed algorithm is RFC1144 */
+	OSMO_ASSERT(comp_entity->algo == RFC_1144);
+
+	/* Run compression algo */
+	rc = rfc1144_compress(&pcomp_index, data, len, comp_entity->state);
+	slhc_i_status(comp_entity->state);
+	slhc_o_status(comp_entity->state);
+
+	/* Find pcomp value */
+	*pcomp = gprs_sndcp_comp_get_comp(comp_entity, pcomp_index);
+
+	LOGP(DSNDCP, LOGL_DEBUG, "Header compression mode: pcomp=%d\n", *pcomp);
+
+	LOGP(DSNDCP, LOGL_DEBUG,
+	     "Header compression done, old length=%d, new length=%d, entity=%p\n",
+	     len, rc, comp_entity);
+	return rc;
+}