Crc && table needs update refactor

src/crc32.c

@@ -27,7 +27,10 @@
  * it contains the precomputed table
  */
 
+#include "crc32.h"
+
 #include <stdint.h>
+#include "ts.h"
 
 /**CRC table for PAT rebuilding, cam support and autoconfiguration*/
 uint32_t crc32_table[256] =
@@ -98,3 +101,34 @@ uint32_t crc32_table[256] =
 	0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
 };
 
+/**
+ * @brief CRC32 calculation inspired by the xine project
+ * @param data to be hashed
+ * @param len of data
+ * @return CRC32 value of data
+ */
+unsigned long calculateCRC32(const unsigned char *data, int len)
+{
+    // Now we must adjust the CRC32
+    unsigned long crc32 = 0xffffffff;
+    for (int i = 0; i < len; ++i) {
+        crc32 = (crc32 << 8) ^ crc32_table[((crc32 >> 24) ^ data[i]) & 0xff];
+    }
+    return crc32;
+}
+
+/**
+ * @brief Calculates and sets CRC32 for PAT, EIT, SDT, PMT, NIT
+ * @param data pointer to table
+ */
+void setCRC32(unsigned char *data)
+{
+    tbl_h_t *table = (tbl_h_t *)data;
+    int len = 3 + HILO(table->section_length) - 4; // CRC for complete section but CRC (4 Bytes)
+    unsigned long crc32 = calculateCRC32(data, len);
+    // We write the CRC32 to the buffer
+    data[len] = (crc32 >> 24) & 0xff;
+    data[len + 1] = (crc32 >> 16) & 0xff;
+    data[len + 2] = (crc32 >> 8) & 0xff;
+    data[len + 3] = crc32 & 0xff;
+}

src/crc32.h

@@ -0,0 +1,12 @@
+#ifndef _CRC32_H
+#define _CRC32_H
+
+#include <stdint.h>
+
+extern uint32_t crc32_table[256];
+
+unsigned long calculateCRC32(const unsigned char *data, int len);
+
+void setCRC32(unsigned char *data);
+
+#endif //_CRC32_H

src/mumudvb.c

@@ -348,7 +348,8 @@ int main (int argc, char **argv)
 			exit(666); //Right code for a bad daemon no ?
 		}
 
-	//If the user didn't defined a preferred logging way, and we daemonize, we set to syslog (except windows, where we don't, and log to console)
+	//If the user didn't define a preferred logging way, and we daemonize,
+	//we set to syslog (except windows, where we don't, and log to console)
 	if (!no_daemon)
 	{
 		if(log_params.log_type==LOGGING_UNDEFINED)

src/rewrite.c

@@ -231,3 +231,38 @@ void set_continuity_counter(unsigned char *buf,int continuity_counter)
 	ts_header->continuity_counter=continuity_counter;
 }
 
+/** @brief Determines if the table has a newer version than the currently recorded one
+ *
+ * In the table there is a field to say if the table was updated
+ * This function checks if it has changed (in order to rewrite the table only once)
+ * @note Note in case it change during streaming, it can be a problem,
+ * and we would have to deal with re-autoconfiguration
+ * @note Note this function can give false positive since it doesn't check the CRC32
+ *
+ * @param mod_log_module The log module of the calling function
+ * @param stored_version The current version to be checked against
+ * @param buf the received packet that is to be checked
+ * @param table_condition pass either NULL or a function that checks the table for preconditions
+ * @returns true if the packet is the beginning of an applicable table and contains a new version, otherwise false
+ */
+bool table_needs_update(char *mod_log_module, const int stored_version, unsigned char *buf,
+	bool (*table_condition)(tbl_h_t *table)) {
+	tbl_h_t *table=(tbl_h_t *)(get_ts_begin(buf));
+
+	// Check if it's the beginning of a new table
+	if (!table) return false;
+	/* current_next_indicator – A 1-bit indicator, which when set to '1' indicates that the table
+	sent is currently applicable. When the bit is set to '0', it indicates that the table sent is not yet applicable
+	and shall be the next table to become valid.  */
+	if (table->current_next_indicator == 0) {
+		return false;
+	}
+	if (table_condition != NULL && table_condition(table) == false) {
+		return false;
+	}
+	if (table->version_number!=stored_version) {
+		log_message(mod_log_module, MSG_DEBUG,"Need update. stored version : %d, new: %d\n",stored_version,table->version_number);
+		return true;
+	}
+	return false;
+}

src/rewrite.h

@@ -151,4 +151,6 @@ void eit_rewrite_new_global_packet(unsigned char *ts_packet, rewrite_parameters_
 void eit_rewrite_new_channel_packet(unsigned char *ts_packet, rewrite_parameters_t *rewrite_vars, mumudvb_channel_t *channel,
 		unicast_parameters_t *unicast_vars, void *scam_vars_v);
 
+bool table_needs_update(char *mod_log_module, int stored_version, unsigned char *buf,
+	bool (*table_condition)(tbl_h_t *table));
 #endif

src/rewrite_pat.c

@@ -33,48 +33,15 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "crc32.h"
 #include "mumudvb.h"
 #include "ts.h"
 #include "rewrite.h"
 #include "log.h"
 #include <stdint.h>
 
-extern uint32_t       crc32_table[256];
 static char *log_module="PAT Rewrite: ";
 
-/** @brief, tell if the pat have a newer version than the one recorded actually
- * In the PAT pid there is a field to say if the PAT was updated
- * This function check if it has changed (in order to rewrite the pat only once)
- * General Note : in case it change during streaming it can be a problem ane we would have to deal with re-autoconfiguration
- * Note this function can give flase positive since it doesn't check the CRC32
- *
- *@param rewrite_vars the parameters for pat rewriting 
- *@param buf : the received buffer
- */
-int pat_need_update(rewrite_parameters_t *rewrite_vars, unsigned char *buf)
-{
-	pat_t       *pat=(pat_t*)(get_ts_begin(buf));
-
-
-	if(pat) //It's the beginning of a new packet
-	{
-		/*current_next_indicator – A 1-bit indicator, which when set to '1' indicates that the Program Association Table
-    sent is currently applicable. When the bit is set to '0', it indicates that the table sent is not yet applicable
-    and shall be the next table to become valid.*/
-		if(pat->current_next_indicator == 0)
-		{
-			return 0;
-		}
-		if(pat->version_number!=rewrite_vars->pat_version)
-		{
-			log_message( log_module, MSG_DEBUG,"Need update. stored version : %d, new: %d\n",rewrite_vars->pat_version,pat->version_number);
-			return 1;
-		}
-	}
-	return 0;
-
-}
-
 /** @brief update the version using the dowloaded pat*/
 void update_pat_version(rewrite_parameters_t *rewrite_vars)
 {
@@ -187,26 +154,8 @@ int pat_channel_rewrite(rewrite_parameters_t *rewrite_vars, mumudvb_channel_t *c
 	buf_dest[1+TS_HEADER_LEN]=(((new_section_length)&0x0f00)>>8)  | (0xf0 & buf_dest[1+TS_HEADER_LEN]);
 	buf_dest[2+TS_HEADER_LEN]=new_section_length & 0xff;
 
-
-	//CRC32 calculation inspired by the xine project
-	//Now we must adjust the CRC32
-	//we compute the CRC32
-	crc32=0xffffffff;
-	for(i = 0; i < new_section_length-1; i++) {
-		crc32 = (crc32 << 8) ^ crc32_table[((crc32 >> 24) ^ buf_dest[i+TS_HEADER_LEN])&0xff];
-	}
-
-
-	//We write the CRC32 to the buffer
-	buf_dest[buf_dest_pos]=(crc32>>24) & 0xff;
-	buf_dest_pos+=1;
-	buf_dest[buf_dest_pos]=(crc32>>16) & 0xff;
-	buf_dest_pos+=1;
-	buf_dest[buf_dest_pos]=(crc32>>8) & 0xff;
-	buf_dest_pos+=1;
-	buf_dest[buf_dest_pos]=crc32 & 0xff;
-	buf_dest_pos+=1;
-
+	setCRC32(buf_dest + TS_HEADER_LEN);
+	buf_dest_pos += 4;
 
 	//Padding with 0xFF
 	memset(buf_dest+buf_dest_pos,0xFF,TS_PACKET_SIZE-buf_dest_pos);
@@ -226,7 +175,7 @@ void pat_rewrite_new_global_packet(unsigned char *ts_packet, rewrite_parameters_
 	/*Check the version before getting the full packet*/
 	if(!rewrite_vars->pat_needs_update)
 	{
-		rewrite_vars->pat_needs_update=pat_need_update(rewrite_vars,ts_packet);
+		rewrite_vars->pat_needs_update=table_needs_update(log_module, rewrite_vars->pat_version, ts_packet, NULL);
 	}
 	/*We need to update the full packet, we download it*/
 	if(rewrite_vars->pat_needs_update)

src/rewrite_pmt.c

@@ -39,6 +39,7 @@
 #include <string.h>
 #include <math.h>
 
+#include "crc32.h"
 #include "mumudvb.h"
 #include "ts.h"
 #include "rewrite.h"
@@ -179,23 +180,8 @@ int pmt_channel_rewrite(mumudvb_channel_t *channel) {
 	buf_dest[1 + TS_HEADER_LEN] = (((new_section_length) & 0x0f00) >> 8) | (0xf0 & buf_dest[1 + TS_HEADER_LEN]);
 	buf_dest[2 + TS_HEADER_LEN] = new_section_length & 0xff;
 
-	//CRC32 calculation inspired by the xine project
-	//Now we must adjust the CRC32
-	//we compute the CRC32
-	crc32 = 0xffffffff;
-	for (i = 0; i < new_section_length - 1; i++) {
-		crc32 = (crc32 << 8) ^ crc32_table[((crc32 >> 24) ^ buf_dest[i + TS_HEADER_LEN]) & 0xff];
-	}
-
-	//We write the CRC32 to the buffer
-	buf_dest[buf_dest_pos] = (crc32 >> 24) & 0xff;
-	buf_dest_pos += 1;
-	buf_dest[buf_dest_pos] = (crc32 >> 16) & 0xff;
-	buf_dest_pos += 1;
-	buf_dest[buf_dest_pos] = (crc32 >> 8) & 0xff;
-	buf_dest_pos += 1;
-	buf_dest[buf_dest_pos] = crc32 & 0xff;
-	buf_dest_pos += 1;
+	setCRC32(buf_dest);
+	buf_dest_pos += 4;
 
 	//Padding with 0xFF
 	memset(buf_dest + buf_dest_pos, 0xFF, TS_PACKET_SIZE - buf_dest_pos);

src/rewrite_sdt.c

@@ -33,6 +33,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "crc32.h"
 #include "mumudvb.h"
 #include "ts.h"
 #include "rewrite.h"
@@ -57,40 +58,16 @@ int sdt_rewrite_all_sections_seen(rewrite_parameters_t *rewrite_vars)
 	return all_seen;
 }
 
-
-
-/** @brief, tell if the sdt have a newer version than the one recorded actually
- * In the SDT pid there is a field to say if the SDT was updated
- * This function check if it has changed (in order to rewrite the sdt only once)
- * General Note : in case it change during streaming it can be a problem ane we would have to deal with re-autoconfiguration
- * Note this function can give flase positive since it doesn't check the CRC32
- *
- *@param rewrite_vars the parameters for sdt rewriting 
- *@param buf : the received buffer
+/**
+ * @brief Check if sdt section describes actual transport stream
  */
-int sdt_need_update(rewrite_parameters_t *rewrite_vars, unsigned char *buf)
+bool actual_subtable_id(tbl_h_t *section)
 {
-	sdt_t       *sdt=(sdt_t*)(get_ts_begin(buf));
-	if(sdt) //It's the beginning of a new packet
-		if((sdt->version_number!=rewrite_vars->sdt_version) && (sdt->table_id==0x42))
-		{
-			/*current_next_indicator – A 1-bit indicator, which when set to '1' indicates that the Program Association Table
-        sent is currently applicable. When the bit is set to '0', it indicates that the table sent is not yet applicable
-        and shall be the next table to become valid.*/
-			if(sdt->current_next_indicator == 0)
-			{
-				return 0;
-			}
-			log_message( log_module, MSG_DEBUG,"Need update. stored version : %d, new: %d\n",rewrite_vars->sdt_version,sdt->version_number);
-			if(rewrite_vars->sdt_version!=-1)
-				log_message( log_module, MSG_INFO,"The SDT version changed, so the channels names changed probably.\n");
-			return 1;
-		}
-	return 0;
-
+	const sdt_t *sdt_section = (sdt_t*)section;
+	return sdt_section->table_id == SDT_ACTUAL_TS;
 }
 
-/** @brief update the version using the dowloaded SDT*/
+/** @brief update the version using the downloaded SDT*/
 void update_sdt_version(rewrite_parameters_t *rewrite_vars)
 {
 	sdt_t       *sdt=(sdt_t*)(rewrite_vars->full_sdt->data_full);
@@ -154,7 +131,8 @@ int sdt_channel_rewrite(rewrite_parameters_t *rewrite_vars, mumudvb_channel_t *c
 
 	if(!channel->service_id)
 	{
-		log_message( log_module, MSG_WARN,"Cannot rewrite a program without the service_id set. We deactivate SDT rewrititng for this channel %d : \"%s\"\n", curr_channel, channel->name);
+		log_message( log_module, MSG_WARN,"Cannot rewrite a program without the service_id set. "
+            "We deactivate SDT rewrititng for this channel %d : \"%s\"\n", curr_channel, channel->name);
 		channel->sdt_rewrite_skip=1;
 		return 0;
 	}
@@ -234,7 +212,7 @@ int sdt_channel_rewrite(rewrite_parameters_t *rewrite_vars, mumudvb_channel_t *c
 			else
 			{
 				log_message( log_module, MSG_DETAIL,"NEW program for channel %d : \"%s\". service_id : %d\n", curr_channel, channel->name,channel->service_id);
-				//we found a announce for a program in our stream, we keep it
+				//we found an announcement for a program in our stream, we keep it
 				//We fill the descriptor loop length
 				t_buffer_ptr->descriptors_loop_length_lo = (loop_length & 0x00FF);
 				t_buffer_ptr->descriptors_loop_length_hi = (loop_length & 0xFF00)>>8;
@@ -274,27 +252,8 @@ int sdt_channel_rewrite(rewrite_parameters_t *rewrite_vars, mumudvb_channel_t *c
 	buf_dest[1+TS_HEADER_LEN]=(((new_section_length)&0x0f00)>>8)  | (0xf0 & buf_dest[1+TS_HEADER_LEN]);
 	buf_dest[2+TS_HEADER_LEN]=new_section_length & 0xff;
 
-
-	//CRC32 calculation inspired by the xine project
-	//Now we must adjust the CRC32
-	//we compute the CRC32
-	crc32=0xffffffff;
-	int i;
-	for(i = 0; i < new_section_length-1; i++) {
-		crc32 = (crc32 << 8) ^ crc32_table[((crc32 >> 24) ^ buf_dest[i+TS_HEADER_LEN])&0xff];
-	}
-
-
-	//We write the CRC32 to the buffer
-	buf_dest[buf_dest_pos]=(crc32>>24) & 0xff;
-	buf_dest_pos+=1;
-	buf_dest[buf_dest_pos]=(crc32>>16) & 0xff;
-	buf_dest_pos+=1;
-	buf_dest[buf_dest_pos]=(crc32>>8) & 0xff;
-	buf_dest_pos+=1;
-	buf_dest[buf_dest_pos]=crc32 & 0xff;
-	buf_dest_pos+=1;
-
+	setCRC32(buf_dest + TS_HEADER_LEN);
+	buf_dest_pos += 4;
 
 	//Padding with 0xFF
 	memset(buf_dest+buf_dest_pos,0xFF,TS_PACKET_SIZE-buf_dest_pos);
@@ -337,9 +296,12 @@ int sdt_rewrite_new_global_packet(unsigned char *ts_packet, rewrite_parameters_t
 	/*Check the version before getting the full packet*/
 	if(!rewrite_vars->sdt_needs_update)
 	{
-		rewrite_vars->sdt_needs_update=sdt_need_update(rewrite_vars,ts_packet);
-		if(rewrite_vars->sdt_needs_update) //It needs update we mark the packet as empty and we clear the sections seen
+		rewrite_vars->sdt_needs_update = table_needs_update(log_module, rewrite_vars->sdt_version,
+			ts_packet, actual_subtable_id);
+		if(rewrite_vars->sdt_needs_update) //It needs update we mark the packet as empty, and we clear the sections seen
 		{
+			if(rewrite_vars->sdt_version != -1)
+				log_message( log_module, MSG_INFO,"The SDT version changed, so the channels names changed probably.");
 			//We clear the section numbers seen
 			memset(&rewrite_vars->sdt_section_numbers_seen,0,sizeof(rewrite_vars->sdt_section_numbers_seen));
 		}
@@ -393,8 +355,9 @@ int sdt_rewrite_new_global_packet(unsigned char *ts_packet, rewrite_parameters_t
 }
 
 
-/** @brief This function is called when a new SDT packet for a channel is there and we asked for rewrite
- * This function copy the rewritten SDT to the buffer. And checks if the SDT was changed so the rewritten version have to be updated
+/** @brief This function is called when a new SDT packet for a channel is there, and we asked for rewrite
+ * This function copies the rewritten SDT to the buffer and checks if the SDT was changed
+ * so the rewritten version has to be updated
  */
 int sdt_rewrite_new_channel_packet(unsigned char *ts_packet, rewrite_parameters_t *rewrite_vars, mumudvb_channel_t *channel, int curr_channel)
 {

src/ts.c

@@ -55,12 +55,12 @@ void add_ts_packet_data(unsigned char *buf, mumudvb_ts_packet_t *pkt, int data_l
  *  * the continuity counter which is incremented for each packet
  *  * The payload_unit_start_indicator which says if it's the first packet
  *
- * When a packet is splitted in 188 bytes packets, there must be no other PID between two sub packets
+ * When a packet is split in 188 bytes packets, there must be no other PID between two sub packets
  *
  * Return 1 when there is one packet full and OK
  *
  * @param buf : the received buffer from the card
- * @param ts_packet : the packet to be completed
+ * @param pkt : the packet to be completed
  */
 int get_ts_packet(unsigned char *buf, mumudvb_ts_packet_t *pkt)
 {