* technically be broken into one or more sections, we do not do this here,
* hence 'table' and 'section' are interchangeable for vidtv.
*
- * This code currently supports three tables: PAT, PMT and SDT. These are the
- * bare minimum to get userspace to recognize our MPEG transport stream. It can
- * be extended to support more PSI tables in the future.
- *
* Copyright (C) 2020 Daniel W. S. Almeida
*/
return desc;
}
+struct vidtv_psi_desc_network_name
+*vidtv_psi_network_name_desc_init(struct vidtv_psi_desc *head, char *network_name)
+{
+ struct vidtv_psi_desc_network_name *desc;
+ u32 network_name_len = network_name ? strlen(network_name) : 0;
+
+ desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+
+ desc->type = NETWORK_NAME_DESCRIPTOR;
+
+ desc->length = network_name_len;
+
+ if (network_name && network_name_len)
+ desc->network_name = kstrdup(network_name, GFP_KERNEL);
+
+ if (head) {
+ while (head->next)
+ head = head->next;
+
+ head->next = (struct vidtv_psi_desc *)desc;
+ }
+
+ return desc;
+}
+
+struct vidtv_psi_desc_service_list
+*vidtv_psi_service_list_desc_init(struct vidtv_psi_desc *head,
+ struct vidtv_psi_desc_service_list_entry *entry)
+{
+ struct vidtv_psi_desc_service_list *desc;
+ struct vidtv_psi_desc_service_list_entry *curr_e = NULL;
+ struct vidtv_psi_desc_service_list_entry *head_e = NULL;
+ struct vidtv_psi_desc_service_list_entry *prev_e = NULL;
+ u16 length = 0;
+
+ desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+
+ desc->type = SERVICE_LIST_DESCRIPTOR;
+
+ while (entry) {
+ curr_e = kzalloc(sizeof(*curr_e), GFP_KERNEL);
+ curr_e->service_id = entry->service_id;
+ curr_e->service_type = entry->service_type;
+
+ length += sizeof(struct vidtv_psi_desc_service_list_entry) -
+ sizeof(struct vidtv_psi_desc_service_list_entry *);
+
+ if (!head_e)
+ head_e = curr_e;
+ if (prev_e)
+ prev_e->next = curr_e;
+
+ prev_e = curr_e;
+ entry = entry->next;
+ }
+
+ desc->length = length;
+ desc->service_list = head_e;
+
+ if (head) {
+ while (head->next)
+ head = head->next;
+
+ head->next = (struct vidtv_psi_desc *)desc;
+ }
+
+ return desc;
+}
+
struct vidtv_psi_desc *vidtv_psi_desc_clone(struct vidtv_psi_desc *desc)
{
struct vidtv_psi_desc *head = NULL;
struct vidtv_psi_desc *curr = NULL;
struct vidtv_psi_desc_service *service;
+ struct vidtv_psi_desc_network_name *desc_network_name;
+ struct vidtv_psi_desc_service_list *desc_service_list;
while (desc) {
switch (desc->type) {
service->provider_name);
break;
+ case NETWORK_NAME_DESCRIPTOR:
+ desc_network_name = (struct vidtv_psi_desc_network_name *)desc;
+ curr = (struct vidtv_psi_desc *)
+ vidtv_psi_network_name_desc_init(head,
+ desc_network_name->network_name);
+ break;
+
+ case SERVICE_LIST_DESCRIPTOR:
+ desc_service_list = (struct vidtv_psi_desc_service_list *)desc;
+ curr = (struct vidtv_psi_desc *)
+ vidtv_psi_service_list_desc_init(head,
+ desc_service_list->service_list);
+ break;
+
case REGISTRATION_DESCRIPTOR:
default:
curr = kzalloc(sizeof(*desc) + desc->length, GFP_KERNEL);
{
struct vidtv_psi_desc *curr = desc;
struct vidtv_psi_desc *tmp = NULL;
+ struct vidtv_psi_desc_service_list_entry *sl_entry = NULL;
+ struct vidtv_psi_desc_service_list_entry *sl_entry_tmp = NULL;
while (curr) {
tmp = curr;
/* nothing to do */
break;
+ case NETWORK_NAME_DESCRIPTOR:
+ kfree(((struct vidtv_psi_desc_network_name *)tmp)->network_name);
+ break;
+
+ case SERVICE_LIST_DESCRIPTOR:
+ sl_entry = ((struct vidtv_psi_desc_service_list *)tmp)->service_list;
+ while (sl_entry) {
+ sl_entry_tmp = sl_entry;
+ sl_entry = sl_entry->next;
+ kfree(sl_entry_tmp);
+ }
+ break;
+
default:
pr_warn_ratelimited("Possible leak: not handling descriptor type %d\n",
tmp->type);
/* the number of bytes written by this function */
u32 nbytes = 0;
struct psi_write_args psi_args = {};
+ struct vidtv_psi_desc_service_list_entry *serv_list_entry = NULL;
psi_args.dest_buf = args.dest_buf;
psi_args.from = &args.desc->type;
nbytes += vidtv_psi_ts_psi_write_into(psi_args);
break;
+ case NETWORK_NAME_DESCRIPTOR:
+ psi_args.dest_offset = args.dest_offset + nbytes;
+ psi_args.len = args.desc->length;
+ psi_args.from = ((struct vidtv_psi_desc_network_name *)args.desc)->network_name;
+
+ nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+ break;
+
+ case SERVICE_LIST_DESCRIPTOR:
+ serv_list_entry = ((struct vidtv_psi_desc_service_list *)args.desc)->service_list;
+ while (serv_list_entry) {
+ psi_args.dest_offset = args.dest_offset + nbytes;
+ psi_args.len = sizeof(struct vidtv_psi_desc_service_list_entry) -
+ sizeof(struct vidtv_psi_desc_service_list_entry *);
+ psi_args.from = serv_list_entry;
+
+ nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+ serv_list_entry = serv_list_entry->next;
+ }
+ break;
+
case REGISTRATION_DESCRIPTOR:
default:
psi_args.dest_offset = args.dest_offset + nbytes;
}
length += CRC_SIZE_IN_BYTES;
-
vidtv_psi_set_sec_len(&sdt->header, length);
}
return NULL; /* not found */
}
+
+static void vidtv_psi_nit_table_update_sec_len(struct vidtv_psi_table_nit *nit)
+{
+ u16 length = 0;
+ struct vidtv_psi_table_transport *t = nit->transport;
+ u16 desc_loop_len;
+ u16 transport_loop_len = 0;
+
+ /*
+ * from immediately after 'section_length' until
+ * 'network_descriptor_length'
+ */
+ length += NIT_LEN_UNTIL_NETWORK_DESCRIPTOR_LEN;
+
+ desc_loop_len = vidtv_psi_desc_comp_loop_len(nit->descriptor);
+ vidtv_psi_set_desc_loop_len(&nit->bitfield, desc_loop_len, 12);
+
+ length += desc_loop_len;
+
+ length += sizeof_field(struct vidtv_psi_table_nit, bitfield2);
+
+ while (t) {
+ /* skip both pointers at the end */
+ transport_loop_len += sizeof(struct vidtv_psi_table_transport) -
+ sizeof(struct vidtv_psi_desc *) -
+ sizeof(struct vidtv_psi_table_transport *);
+
+ length += transport_loop_len;
+
+ desc_loop_len = vidtv_psi_desc_comp_loop_len(t->descriptor);
+ vidtv_psi_set_desc_loop_len(&t->bitfield, desc_loop_len, 12);
+
+ length += desc_loop_len;
+
+ t = t->next;
+ }
+
+ // Actually sets the transport stream loop len, maybe rename this function later
+ vidtv_psi_set_desc_loop_len(&nit->bitfield2, transport_loop_len, 12);
+ length += CRC_SIZE_IN_BYTES;
+
+ vidtv_psi_set_sec_len(&nit->header, length);
+}
+
+struct vidtv_psi_table_nit
+*vidtv_psi_nit_table_init(u16 network_id,
+ u16 transport_stream_id,
+ char *network_name,
+ struct vidtv_psi_desc_service_list_entry *service_list)
+{
+ struct vidtv_psi_table_nit *nit = kzalloc(sizeof(*nit), GFP_KERNEL);
+ struct vidtv_psi_table_transport *transport = kzalloc(sizeof(*transport), GFP_KERNEL);
+
+ const u16 SYNTAX = 0x1;
+ const u16 ONE = 0x1;
+ const u16 ONES = 0x03;
+
+ nit->header.table_id = 0x40; // ACTUAL_NETWORK
+
+ nit->header.bitfield = cpu_to_be16((SYNTAX << 15) | (ONE << 14) | (ONES << 12));
+
+ nit->header.id = cpu_to_be16(network_id);
+ nit->header.current_next = ONE;
+
+ nit->header.version = 0x1f;
+
+ nit->header.one2 = ONES;
+ nit->header.section_id = 0;
+ nit->header.last_section = 0;
+
+ nit->bitfield = cpu_to_be16(0xf);
+ nit->bitfield2 = cpu_to_be16(0xf);
+
+ nit->descriptor = (struct vidtv_psi_desc *)
+ vidtv_psi_network_name_desc_init(NULL, network_name);
+
+ transport->transport_id = cpu_to_be16(transport_stream_id);
+ transport->network_id = cpu_to_be16(network_id);
+ transport->bitfield = cpu_to_be16(0xf);
+ transport->descriptor = (struct vidtv_psi_desc *)
+ vidtv_psi_service_list_desc_init(NULL, service_list);
+
+ nit->transport = transport;
+
+ vidtv_psi_nit_table_update_sec_len(nit);
+
+ return nit;
+}
+
+u32 vidtv_psi_nit_write_into(struct vidtv_psi_nit_write_args args)
+{
+ /* the number of bytes written by this function */
+ u32 nbytes = 0;
+ u32 crc = INITIAL_CRC;
+
+ struct vidtv_psi_desc *table_descriptor = args.nit->descriptor;
+ struct vidtv_psi_table_transport *transport = args.nit->transport;
+ struct vidtv_psi_desc *transport_descriptor = (transport) ?
+ args.nit->transport->descriptor :
+ NULL;
+
+ struct header_write_args h_args = {};
+ struct psi_write_args psi_args = {};
+ struct desc_write_args d_args = {};
+ struct crc32_write_args c_args = {};
+
+ vidtv_psi_nit_table_update_sec_len(args.nit);
+
+ h_args.dest_buf = args.buf;
+ h_args.dest_offset = args.offset;
+ h_args.h = &args.nit->header;
+ h_args.pid = VIDTV_NIT_PID;
+ h_args.continuity_counter = args.continuity_counter;
+ h_args.dest_buf_sz = args.buf_sz;
+ h_args.crc = &crc;
+
+ nbytes += vidtv_psi_table_header_write_into(h_args);
+
+ /* write the bitfield */
+ psi_args.dest_buf = args.buf;
+ psi_args.from = &args.nit->bitfield;
+ psi_args.len = sizeof_field(struct vidtv_psi_table_nit, bitfield);
+
+ psi_args.dest_offset = args.offset + nbytes;
+ psi_args.pid = VIDTV_NIT_PID;
+ psi_args.new_psi_section = false;
+ psi_args.continuity_counter = args.continuity_counter;
+ psi_args.is_crc = false;
+ psi_args.dest_buf_sz = args.buf_sz;
+ psi_args.crc = &crc;
+
+ nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+ while (table_descriptor) {
+ /* write the descriptors, if any */
+ d_args.dest_buf = args.buf;
+ d_args.dest_offset = args.offset + nbytes;
+ d_args.desc = table_descriptor;
+ d_args.pid = VIDTV_NIT_PID;
+ d_args.continuity_counter = args.continuity_counter;
+ d_args.dest_buf_sz = args.buf_sz;
+ d_args.crc = &crc;
+
+ nbytes += vidtv_psi_desc_write_into(d_args);
+
+ table_descriptor = table_descriptor->next;
+ }
+
+ /* write the second bitfield */
+ psi_args.dest_buf = args.buf;
+ psi_args.from = &args.nit->bitfield2;
+ psi_args.len = sizeof_field(struct vidtv_psi_table_nit, bitfield2);
+ psi_args.dest_offset = args.offset + nbytes;
+ psi_args.pid = VIDTV_NIT_PID;
+
+ nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+ while (transport) {
+ /* write the transport sections, if any */
+ psi_args.from = transport;
+ psi_args.len = sizeof_field(struct vidtv_psi_table_transport, transport_id) +
+ sizeof_field(struct vidtv_psi_table_transport, network_id) +
+ sizeof_field(struct vidtv_psi_table_transport, bitfield);
+ psi_args.dest_offset = args.offset + nbytes;
+
+ nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+ while (transport_descriptor) {
+ /* write the transport descriptors, if any */
+ d_args.dest_buf = args.buf;
+ d_args.dest_offset = args.offset + nbytes;
+ d_args.desc = transport_descriptor;
+ d_args.pid = VIDTV_NIT_PID;
+ d_args.continuity_counter = args.continuity_counter;
+ d_args.dest_buf_sz = args.buf_sz;
+ d_args.crc = &crc;
+
+ nbytes += vidtv_psi_desc_write_into(d_args);
+
+ transport_descriptor = transport_descriptor->next;
+ }
+
+ transport = transport->next;
+ }
+
+ c_args.dest_buf = args.buf;
+ c_args.dest_offset = args.offset + nbytes;
+ c_args.crc = cpu_to_be32(crc);
+ c_args.pid = VIDTV_NIT_PID;
+ c_args.continuity_counter = args.continuity_counter;
+ c_args.dest_buf_sz = args.buf_sz;
+
+ /* Write the CRC32 at the end */
+ nbytes += table_section_crc32_write_into(c_args);
+
+ return nbytes;
+}
+
+static void vidtv_psi_transport_destroy(struct vidtv_psi_table_transport *t)
+{
+ struct vidtv_psi_table_transport *curr_t = t;
+ struct vidtv_psi_table_transport *tmp_t = NULL;
+
+ while (curr_t) {
+ tmp_t = curr_t;
+ curr_t = curr_t->next;
+ vidtv_psi_desc_destroy(tmp_t->descriptor);
+ kfree(tmp_t);
+ }
+}
+
+void vidtv_psi_nit_table_destroy(struct vidtv_psi_table_nit *nit)
+{
+ vidtv_psi_desc_destroy(nit->descriptor);
+ vidtv_psi_transport_destroy(nit->transport);
+ kfree(nit);
+}
* technically be broken into one or more sections, we do not do this here,
* hence 'table' and 'section' are interchangeable for vidtv.
*
- * This code currently supports three tables: PAT, PMT and SDT. These are the
- * bare minimum to get userspace to recognize our MPEG transport stream. It can
- * be extended to support more PSI tables in the future.
- *
* Copyright (C) 2020 Daniel W. S. Almeida
*/
#define PAT_LEN_UNTIL_LAST_SECTION_NUMBER 5
#define PMT_LEN_UNTIL_PROGRAM_INFO_LENGTH 9
#define SDT_LEN_UNTIL_RESERVED_FOR_FUTURE_USE 8
+#define NIT_LEN_UNTIL_NETWORK_DESCRIPTOR_LEN 7
#define MAX_SECTION_LEN 1021
#define VIDTV_PAT_PID 0 /* mandated by the specs */
#define VIDTV_SDT_PID 0x0011 /* mandated by the specs */
+#define VIDTV_NIT_PID 0x0010 /* mandated by the specs */
enum vidtv_psi_descriptors {
REGISTRATION_DESCRIPTOR = 0x05, /* See ISO/IEC 13818-1 section 2.6.8 */
+ NETWORK_NAME_DESCRIPTOR = 0x40, /* See ETSI EN 300 468 section 6.2.27 */
+ SERVICE_LIST_DESCRIPTOR = 0x41, /* See ETSI EN 300 468 section 6.2.35 */
SERVICE_DESCRIPTOR = 0x48, /* See ETSI EN 300 468 section 6.2.33 */
};
u8 additional_identification_info[];
} __packed;
+/**
+ * struct vidtv_psi_desc_network_name - A network name descriptor
+ * see ETSI EN 300 468 v1.15.1 section 6.2.27
+ */
+struct vidtv_psi_desc_network_name {
+ struct vidtv_psi_desc *next;
+ u8 type;
+ u8 length;
+ char *network_name;
+} __packed;
+
+struct vidtv_psi_desc_service_list_entry {
+ __be16 service_id;
+ u8 service_type;
+ struct vidtv_psi_desc_service_list_entry *next;
+} __packed;
+
+/**
+ * struct vidtv_psi_desc_service_list - A service list descriptor
+ * see ETSI EN 300 468 v1.15.1 section 6.2.35
+ */
+struct vidtv_psi_desc_service_list {
+ struct vidtv_psi_desc *next;
+ u8 type;
+ u8 length;
+ struct vidtv_psi_desc_service_list_entry *service_list;
+} __packed;
+
/**
* struct vidtv_psi_table_header - A header that is present for all PSI tables.
*/
u8 *additional_ident_info,
u32 additional_info_len);
+struct vidtv_psi_desc_network_name
+*vidtv_psi_network_name_desc_init(struct vidtv_psi_desc *head, char *network_name);
+
+struct vidtv_psi_desc_service_list
+*vidtv_psi_service_list_desc_init(struct vidtv_psi_desc *head,
+ struct vidtv_psi_desc_service_list_entry *entry);
+
struct vidtv_psi_table_pat_program
*vidtv_psi_pat_program_init(struct vidtv_psi_table_pat_program *head,
u16 service_id,
u16 vidtv_psi_get_pat_program_pid(struct vidtv_psi_table_pat_program *p);
u16 vidtv_psi_pmt_stream_get_elem_pid(struct vidtv_psi_table_pmt_stream *s);
+/**
+ * struct vidtv_psi_table_transport - A entry in the TS loop for the NIT and/or other tables.
+ * See ETSI 300 468 section 5.2.1
+ * @transport_id: The TS ID being described
+ * @network_id: The network_id that contains the TS ID
+ * @bitfield: Contains the descriptor loop length
+ * @descriptor: A descriptor loop
+ * @next: Pointer to the next entry
+ *
+ */
+struct vidtv_psi_table_transport {
+ __be16 transport_id;
+ __be16 network_id;
+ __be16 bitfield; /* desc_len: 12, reserved: 4 */
+ struct vidtv_psi_desc *descriptor;
+ struct vidtv_psi_table_transport *next;
+} __packed;
+
+/**
+ * struct vidtv_psi_table_nit - A Network Information Table (NIT). See ETSI 300
+ * 468 section 5.2.1
+ * @header: A PSI table header
+ * @bitfield: Contains the network descriptor length
+ * @descriptor: A descriptor loop describing the network
+ * @bitfield2: Contains the transport stream loop length
+ * @transport: The transport stream loop
+ *
+ */
+struct vidtv_psi_table_nit {
+ struct vidtv_psi_table_header header;
+ __be16 bitfield; /* network_desc_len: 12, reserved:4 */
+ struct vidtv_psi_desc *descriptor;
+ __be16 bitfield2; /* ts_loop_len: 12, reserved: 4 */
+ struct vidtv_psi_table_transport *transport;
+} __packed;
+
+struct vidtv_psi_table_nit
+*vidtv_psi_nit_table_init(u16 network_id,
+ u16 transport_stream_id,
+ char *network_name,
+ struct vidtv_psi_desc_service_list_entry *service_list);
+
+/**
+ * struct vidtv_psi_nit_write_args - Arguments for writing a NIT section
+ * @buf: The destination buffer.
+ * @offset: The offset into the destination buffer.
+ * @nit: A pointer to the NIT
+ * @buf_sz: The size of the destination buffer.
+ * @continuity_counter: A pointer to the CC. Incremented on every new packet.
+ *
+ */
+struct vidtv_psi_nit_write_args {
+ char *buf;
+ u32 offset;
+ struct vidtv_psi_table_nit *nit;
+ u32 buf_sz;
+ u8 *continuity_counter;
+};
+
+/**
+ * vidtv_psi_nit_write_into - Write NIT as MPEG-TS packets into a buffer.
+ * @args: an instance of struct vidtv_psi_nit_write_args
+ *
+ * This function writes the MPEG TS packets for a NIT table into a buffer.
+ * Calling code will usually generate the NIT via a call to its init function
+ * and thus is responsible for freeing it.
+ *
+ * Return: The number of bytes written into the buffer. This is NOT
+ * equal to the size of the NIT, since more space is needed for TS headers during TS
+ * encapsulation.
+ */
+u32 vidtv_psi_nit_write_into(struct vidtv_psi_nit_write_args args);
+
+void vidtv_psi_nit_table_destroy(struct vidtv_psi_table_nit *nit);
+
#endif // VIDTV_PSI_H
projects / kernel.git / commitdiff