diff mbox series

[v2,06/15] core: Add utilities to read the provisioning db

Message ID 20231219184016.420116-6-denkenz@gmail.com (mailing list archive)
State Changes Requested, archived
Headers show
Series [v2,01/15] build: Fix typo that breaks --fsanitize=leak check | expand

Commit Message

Denis Kenzior Dec. 19, 2023, 6:37 p.m. UTC
Binary provisioning format is based on a patricia trie / crit-bit tree,
with each MCC + MNC combination represented by a single node.  Each node
contains an array of { SPN, offset } pairs, with the offset pointing to
the region of memory where the context information resides.

Each node also has two offsets, corresponding to left and right children
of the node, as well as the position of the critical bit, based on which
the tree is traversed.

All strings are placed in the last section and are nil terminated.
Structures are designed with 8-byte alignment and stored in little
endian format, which will require no conversion for the vast majority of
platforms in use.
---
 Makefile.am       |   3 +-
 src/provisiondb.c | 439 ++++++++++++++++++++++++++++++++++++++++++++++
 src/provisiondb.h |  18 ++
 3 files changed, 459 insertions(+), 1 deletion(-)
 create mode 100644 src/provisiondb.c
 create mode 100644 src/provisiondb.h

v2

- Changed license to LGPL in case the provisiondb code needs to be
  linked against in other applications.
- Moved provisiondb utilities to the core
diff mbox series

Patch

diff --git a/Makefile.am b/Makefile.am
index f7b59a47..b3a016cf 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -726,7 +726,8 @@  src_ofonod_SOURCES = $(builtin_sources) $(gatchat_sources) src/ofono.ver \
 			src/hfp.h src/siri.c \
 			src/netmon.c src/lte.c src/ims.c \
 			src/netmonagent.c src/netmonagent.h \
-			src/module.c
+			src/module.c \
+			src/provisiondb.h src/provisiondb.c
 
 src_ofonod_LDADD = gdbus/libgdbus-internal.la $(builtin_libadd) $(ell_ldadd) \
 			@GLIB_LIBS@ @DBUS_LIBS@ -ldl
diff --git a/src/provisiondb.c b/src/provisiondb.c
new file mode 100644
index 00000000..0fa454c9
--- /dev/null
+++ b/src/provisiondb.c
@@ -0,0 +1,439 @@ 
+/*
+ *  oFono - Open Source Telephony
+ *  Copyright (C) 2023  Cruise, LLC
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <linux/types.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include <ell/ell.h>
+
+#define OFONO_API_SUBJECT_TO_CHANGE
+#include <ofono/modem.h>
+#include <ofono/gprs-provision.h>
+
+#include "provisiondb.h"
+
+struct provision_header {
+	__le64 version;
+	__le64 file_size;
+	__le64 header_size;
+	__le64 node_struct_size;
+	__le64 provision_data_struct_size;
+	__le64 context_struct_size;
+	__le64 nodes_offset;
+	__le64 nodes_size;
+	__le64 contexts_offset;
+	__le64 contexts_size;
+	__le64 strings_offset;
+	__le64 strings_size;
+
+	/* followed by nodes_size of node structures */
+	/* followed by contexts_size of context structures */
+	/* followed by strings_size packed strings */
+} __attribute__((packed));
+
+struct node {
+	__le64 bit_offsets[2];
+	__le32 mccmnc;
+	__le32 diff; /* Signed */
+	__le64 provision_data_count;
+	/* followed by provision_data_count provision_data structures */
+} __attribute__((packed));
+
+struct provision_data {
+	__le64 spn_offset;
+	__le64 context_offset;	/* the offset contains count of contexts */
+				/* followed by context structures */
+} __attribute__((packed));
+
+struct context {
+	__le32 type; /* Corresponds to ofono_gprs_context_type bitmap */
+	__le32 protocol; /* Corresponds to ofono_gprs_proto */
+	__le32 authentication; /* Corresponds to ofono_gprs_auth_method */
+	__le32 reserved;
+	__le64 name_offset;
+	__le64 apn_offset;
+	__le64 username_offset;
+	__le64 password_offset;
+	__le64 mmsproxy_offset;
+	__le64 mmsc_offset;
+} __attribute__((packed));
+
+struct provision_db {
+	int fd;
+	time_t mtime;
+	size_t size;
+	void *addr;
+	uint64_t nodes_offset;
+	uint64_t nodes_size;
+	uint64_t contexts_offset;
+	uint64_t contexts_size;
+	uint64_t strings_offset;
+	uint64_t strings_size;
+};
+
+struct provision_db *provision_db_new(const char *pathname)
+{
+	struct provision_header *hdr;
+	struct provision_db *pdb = NULL;
+	struct stat st;
+	void *addr;
+	size_t size;
+	int fd;
+
+	if (!pathname)
+		return NULL;
+
+	fd = open(pathname, O_RDONLY | O_CLOEXEC);
+	if (fd < 0)
+		return NULL;
+
+	if (fstat(fd, &st) < 0)
+		goto error_close;
+
+	size = st.st_size;
+	if (size < sizeof(struct provision_header))
+		goto error_close;
+
+	addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
+	if (addr == MAP_FAILED)
+		goto error_close;
+
+	hdr = addr;
+
+	if (L_LE64_TO_CPU(hdr->file_size) != size)
+		goto failed;
+
+	if (L_LE64_TO_CPU(hdr->header_size) != sizeof(struct provision_header))
+		goto failed;
+
+	if (L_LE64_TO_CPU(hdr->node_struct_size) != sizeof(struct node))
+		goto failed;
+
+	if (L_LE64_TO_CPU(hdr->provision_data_struct_size) !=
+			sizeof(struct provision_data))
+		goto failed;
+
+	if (L_LE64_TO_CPU(hdr->context_struct_size) != sizeof(struct context))
+		goto failed;
+
+	if (L_LE64_TO_CPU(hdr->header_size) + L_LE64_TO_CPU(hdr->nodes_size) +
+			L_LE64_TO_CPU(hdr->contexts_size) +
+			L_LE64_TO_CPU(hdr->strings_size) != size)
+		goto failed;
+
+	pdb = l_new(struct provision_db, 1);
+
+	pdb->fd = fd;
+	pdb->mtime = st.st_mtime;
+	pdb->size = size;
+	pdb->addr = addr;
+	pdb->nodes_offset = L_LE64_TO_CPU(hdr->nodes_offset);
+	pdb->nodes_size = L_LE64_TO_CPU(hdr->nodes_size);
+	pdb->contexts_offset = L_LE64_TO_CPU(hdr->contexts_offset);
+	pdb->contexts_size = L_LE64_TO_CPU(hdr->contexts_size);
+	pdb->strings_offset = L_LE64_TO_CPU(hdr->strings_offset);
+	pdb->strings_size = L_LE64_TO_CPU(hdr->strings_size);
+
+	return pdb;
+
+failed:
+	munmap(addr, st.st_size);
+error_close:
+	close(fd);
+	return NULL;
+}
+
+struct provision_db *provision_db_new_default(void)
+{
+	struct provision_db *db = NULL;
+	size_t i;
+	const char * const paths[] = { "/usr/share/ofono/provision.db" };
+
+	for (i = 0; !db && i < L_ARRAY_SIZE(paths); i++)
+		db = provision_db_new(paths[i]);
+
+	return db;
+}
+
+void provision_db_free(struct provision_db *pdb)
+{
+	if (!pdb)
+		return;
+
+	munmap(pdb->addr, pdb->size);
+	close(pdb->fd);
+	l_free(pdb);
+}
+
+static int __get_node(struct provision_db *pdb, uint64_t offset,
+				struct node **out_node)
+{
+	uint64_t count;
+	struct node *node;
+
+	if (offset + sizeof(struct node) > pdb->nodes_size)
+		return -EPROTO;
+
+	node = pdb->addr + pdb->nodes_offset + offset;
+	offset += sizeof(struct node);
+	count = L_LE64_TO_CPU(node->provision_data_count);
+
+	if (offset + count * sizeof(struct provision_data) > pdb->nodes_size)
+		return -EPROTO;
+
+	*out_node = node;
+	return 0;
+}
+
+static struct provision_data *__get_provision_data(struct node *node)
+{
+	return ((void *) node) + sizeof(struct node);
+}
+
+static int __get_string(struct provision_db *pdb, uint64_t offset,
+				char **out_str)
+{
+	if (!offset) {
+		*out_str = NULL;
+		return 0;
+	}
+
+	if (offset >= pdb->strings_size)
+		return -EPROTO;
+
+	*out_str = pdb->addr + pdb->strings_offset + offset;
+	return 0;
+}
+
+static int __get_contexts(struct provision_db *pdb, uint64_t offset,
+				struct ofono_gprs_provision_data **contexts,
+				size_t *n_contexts)
+{
+	void *start = pdb->addr + pdb->contexts_offset;
+	uint64_t num;
+	uint64_t i;
+	struct ofono_gprs_provision_data *ret;
+	int r;
+
+	if (offset + sizeof(__le64) >= pdb->contexts_size)
+		return -EPROTO;
+
+	num = l_get_le64(start + offset);
+	offset += sizeof(__le64);
+
+	if (offset + num * sizeof(struct context) > pdb->contexts_size)
+		return -EPROTO;
+
+	ret = l_new(struct ofono_gprs_provision_data, num);
+
+	for (i = 0; i < num; i++, offset += sizeof(struct context)) {
+		struct context *context = start + offset;
+
+		ret[i].type = L_LE32_TO_CPU(context->type);
+		ret[i].proto = L_LE32_TO_CPU(context->protocol);
+		ret[i].auth_method = L_LE32_TO_CPU(context->authentication);
+
+		if ((r = __get_string(pdb, L_LE64_TO_CPU(context->name_offset),
+					&ret[i].name)) < 0)
+			goto fail;
+
+		if ((r = __get_string(pdb, L_LE64_TO_CPU(context->apn_offset),
+					&ret[i].apn)) < 0)
+			goto fail;
+
+		if ((r = __get_string(pdb,
+					L_LE64_TO_CPU(context->username_offset),
+					&ret[i].username)) < 0)
+			goto fail;
+
+		if ((r = __get_string(pdb,
+					L_LE64_TO_CPU(context->password_offset),
+					&ret[i].password)) < 0)
+			goto fail;
+
+		if ((r = __get_string(pdb,
+					L_LE64_TO_CPU(context->mmsproxy_offset),
+					&ret[i].message_proxy)) < 0)
+			goto fail;
+
+		if ((r = __get_string(pdb, L_LE64_TO_CPU(context->mmsc_offset),
+					&ret[i].message_center)) < 0)
+			goto fail;
+	}
+
+	*contexts = ret;
+	*n_contexts = num;
+	return 0;
+
+fail:
+	l_free(ret);
+	return r;
+}
+
+static uint8_t choose(struct node *node, uint32_t key)
+{
+	return (key >> (31U - L_LE32_TO_CPU(node->diff))) & 1;
+}
+
+static int __find(struct provision_db *pdb, uint32_t key,
+						struct node **out_node)
+{
+	struct node *child;
+	struct node *parent;
+	int r;
+
+	r = __get_node(pdb, 0, &parent);
+	if (r < 0)
+		return r;
+
+	r = __get_node(pdb, L_LE64_TO_CPU(parent->bit_offsets[0]), &child);
+	if (r < 0)
+		return r;
+
+	while ((int32_t) L_LE32_TO_CPU(parent->diff) <
+			(int32_t) L_LE32_TO_CPU(child->diff)) {
+		uint8_t bit = choose(child, key);
+		uint64_t offset = L_LE64_TO_CPU(child->bit_offsets[bit]);
+
+		parent = child;
+
+		r = __get_node(pdb, offset, &child);
+		if (r < 0)
+			return r;
+	}
+
+	if (L_LE32_TO_CPU(child->mccmnc) != key)
+		return -ENOENT;
+
+	*out_node = child;
+	return 0;
+}
+
+static int id_as_num(const char *id, size_t len)
+{
+	uint32_t v = 0;
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		if (!l_ascii_isdigit(id[i]))
+			return -EINVAL;
+
+		v = v * 10 + id[i] - '0';
+	}
+
+	return v;
+}
+
+static int key_from_mcc_mnc(const char *mcc, const char *mnc, uint32_t *key)
+{
+	size_t mcc_len = strlen(mcc);
+	size_t mnc_len = strlen(mnc);
+	uint32_t v;
+	int r;
+
+	if (mcc_len != 3)
+		return -EINVAL;
+
+	if (mnc_len != 2 && mnc_len != 3)
+		return -EINVAL;
+
+	r = id_as_num(mcc, mcc_len);
+	if (r < 0)
+		return r;
+
+	v = r << 11;
+
+	r = id_as_num(mnc, mnc_len);
+	if (r < 0)
+		return r;
+
+	if (mnc_len == 3)
+		v |= 1 << 10;
+
+	v |= r;
+
+	*key = v;
+	return 0;
+}
+
+int provision_db_lookup(struct provision_db *pdb,
+			const char *mcc, const char *mnc, const char *match_spn,
+			struct ofono_gprs_provision_data **items,
+			size_t *n_items)
+{
+	int r;
+	uint32_t key;
+	struct node *node;
+	struct provision_data *data;
+	struct provision_data *found = NULL;
+	uint64_t count;
+	uint64_t i;
+
+	if (pdb == NULL)
+		return -EBADF;
+
+	r = key_from_mcc_mnc(mcc, mnc, &key);
+	if (r < 0)
+		return r;
+
+	/*
+	 * Find the target node, then walk the provision_data items to
+	 * match the spn.  After that it is a matter of allocating the
+	 * return contexts and copying over the details.
+	 */
+
+	r = __find(pdb, key, &node);
+	if (r < 0)
+		return r;
+
+	count = L_LE64_TO_CPU(node->provision_data_count);
+	data = __get_provision_data(node);
+
+	if (!count)
+		return -ENOENT;
+
+	/*
+	 * provision_data objects are sorted by SPN, with no SPN (non-MVNO)
+	 * being first.  Since the provisioning data is imperfect, we try to
+	 * match by SPN, but if that fails, we return the non-SPN entry, if
+	 * present
+	 */
+	if (data[0].spn_offset == 0) {
+		found = data;
+		data += 1;
+		count -= 1;
+	}
+
+	for (i = 0; i < count; i++) {
+		char *spn;
+
+		r = __get_string(pdb, L_LE64_TO_CPU(data[i].spn_offset), &spn);
+		if (r < 0)
+			return r;
+
+		if (l_streq0(spn, match_spn)) {
+			found = data + i;
+			break;
+		}
+	}
+
+	if (!found)
+		return -ENOENT;
+
+	return __get_contexts(pdb, L_LE64_TO_CPU(found->context_offset),
+				items, n_items);
+}
diff --git a/src/provisiondb.h b/src/provisiondb.h
new file mode 100644
index 00000000..d7381b94
--- /dev/null
+++ b/src/provisiondb.h
@@ -0,0 +1,18 @@ 
+/*
+ *  oFono - Open Source Telephony
+ *  Copyright (C) 2023  Cruise, LLC
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+struct ofono_gprs_provision_data;
+struct provision_db;
+
+struct provision_db *provision_db_new(const char *pathname);
+struct provision_db *provision_db_new_default(void);
+void provision_db_free(struct provision_db *pdb);
+
+int provision_db_lookup(struct provision_db *pdb,
+			const char *mcc, const char *mnc, const char *spn,
+			struct ofono_gprs_provision_data **items,
+			size_t *n_items);