opnet的simple_source模块学习

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simple_source模块可以在外部设置的属性

有四个局部统计量，分别为产生的bit速率、包速率、包大小，包间隔

状态机为三个非强制对象，在头文件里定义了自中断和转移条件。

/*Include files. */

#include <oms_dist_support.h>

/*Special attribute values. */

#define SSC_INFINITE_TIME -1.0

/*Interrupt code values. */ 自定义中断

#define SSC_START 0

#define SSC_GENERATE 1

#define SSC_STOP 2

/* Nodeconfiguration constants. */

#define SSC_STRM_TO_LOW 0

/* Macrodefinitions for state */

/*transitions. */定义转移条件

#define START (intrpt_code == SSC_START)

#define DISABLED (intrpt_code == SSC_STOP)

#define STOP (intrpt_code == SSC_STOP)

#define PACKET_GENERATE (intrpt_code == SSC_GENERATE)

/*Function prototypes. */

staticvoid ss_packet_generate(void);

Init非强制状态的入口程序为

/* Atthis initial state, we read the values of source attributes */包含源的属性定义

/* andschedule a selt interrupt that will indicate our start time */表明开始的时间

/* forpacket generation. */

/* Obtainthe object id of the surrounding module. */

own_id = op_id_self ();获得所属处理器或队列的对象ID

/* Readthe values of the packet generation parameters, i.e. the */

/*attribute values of the surrounding module. */获取给定对象的某属性

op_ima_obj_attr_get (own_id,"Packet Interarrival Time", interarrival_str);包间隔

op_ima_obj_attr_get(own_id, "Packet Size", size_str); 包大小

op_ima_obj_attr_get(own_id, "Packet Format", format_str);包格式

op_ima_obj_attr_get(own_id, "Start Time", &start_time);开始时间

op_ima_obj_attr_get(own_id, "Stop Time", &stop_time);停止时间

/* Loadthe PDFs that will be used in computing the packet */

/*interarrival times and packet sizes. */从PDF中加载分布

interarrival_dist_ptr= oms_dist_load_from_string (interarrival_str);

pksize_dist_ptr = oms_dist_load_from_string (size_str);

/* Verifythe existence of the packet format to be used for */

/*generated packets. */

if(strcmp (format_str, "NONE") == 0) 检查是否为无格式的包

{

/* We will generate unformattedpackets. Set the flag. */

generate_unformatted = OPC_TRUE;

}

else

{

/* We will generate formatted packets.Turn off the flag. */

generate_unformatted = OPC_FALSE;

/* Get the list of all available packetformats.*/函数返回一系列包格式的名字

pk_format_names_lptr =prg_tfile_name_list_get (PrgC_Tfile_Type_Packet_Format);

/* Search the list for the requestedpacket format.*/查找所需要的包格式

format_found = OPC_FALSE;

for (i = prg_list_size(pk_format_names_lptr); ((format_found == OPC_FALSE) && (i > 0));i--)

{

/* Access the next formatname and compare with requested */

/* format name. */

found_format_str = (char *)prg_list_access (pk_format_names_lptr, i - 1);

if (strcmp (found_format_str,format_str) == 0)

format_found =OPC_TRUE;找到了所需要的包格式

}

if (format_found == OPC_FALSE)

{

/* The requested format doesnot exist. Generate */

/* unformatted packets. */

generate_unformatted =OPC_TRUE;

/* Display an appropriatewarning.*/没有找到需要的包格式，输出警告

op_prg_odb_print_major("Warning from simple packet generator model (simple_source):",

"Thespecified packet format", format_str,

"isnot found. Generating unformatted packets instead.", OPC_NIL);

}

/* Destroy the lits and its elementssince we don't need it */

/* anymore. */

prg_list_free(pk_format_names_lptr);释放内存

prg_mem_free (pk_format_names_lptr);

}

/* Makesure we have valid start and stop times, i.e. stop time is */

/* notearlier than start time. */

if((stop_time <= start_time) && (stop_time != SSC_INFINITE_TIME))

{如果结束时间早于开始时间或结束时间不为无穷

/* Stop time is earlier than starttime. Disable the source. */

start_time = SSC_INFINITE_TIME; 设置开始时间为无穷并且输出警告

/* Display an appropriate warning. */

op_prg_odb_print_major ("Warningfrom simple packet generator model (simple_source):",

"Althoughthe generator is not disabled (start time is set to a finite value),",

"astop time that is not later than the start time is specified.",

"Disablingthe generator.", OPC_NIL);

}

/*Schedule a self interrupt that will indicate our start time for */

/* packetgeneration activities. If the source is disabled, */

/*schedule it at current time with the appropriate code value. */

if(start_time == SSC_INFINITE_TIME) 如果开始时间是无穷，安排自中断开始时间为仿真时间，否则为实际开始时间

{

op_intrpt_schedule_self (op_sim_time(), SSC_STOP);

}

else

{

op_intrpt_schedule_self (start_time, SSC_START);

/* In this case, also schedule theinterrupt when we will stop */

/* generating packets, unless we areconfigured to run until */

/* the end of the simulation. */ 仿真结束时间安排一个自中断

if (stop_time != SSC_INFINITE_TIME)

{

op_intrpt_schedule_self(stop_time,SSC_STOP);

}

next_intarr_time = oms_dist_outcome(interarrival_dist_ptr);通过一个分布生成一个浮点数

/* Make sure that interarrival time isnot negative. In that case it */

/* will be set to 0. */确认间隔时间不为负，否则设为0

if (next_intarr_time <0)

{

next_intarr_time = 0.0;

}

/*Register the statistics that will be maintained by this model. */声明局部统计量

bits_sent_hndl =op_stat_reg ("Generator.Traffic Sent (bits/sec)", OPC_STAT_INDEX_NONE,OPC_STAT_LOCAL);

packets_sent_hndl = op_stat_reg ("Generator.Traffic Sent(packets/sec)", OPC_STAT_INDEX_NONE,OPC_STAT_LOCAL);

packet_size_hndl = op_stat_reg ("Generator.Packet Size(bits)", OPC_STAT_INDEX_NONE, OPC_STAT_LOCAL);

interarrivals_hndl = op_stat_reg ("Generator.PacketInterarrival Time (secs)", OPC_STAT_INDEX_NONE, OPC_STAT_LOCAL);

init出口程序

/*Determine the code of the interrupt, which is used in evaluating */

/* statetransition conditions. */

intrpt_code= op_intrpt_code ();

init转到generate状态时的执行的函数代码

staticvoid

ss_packet_generate(void)

{

Packet* pkptr;

double pksize;

/** This function creates a packetbased on the packet generation**/

/** specifications of the source modeland sends it to the lower layer.**/

FIN (ss_packet_generate ());

/* Generate a packet size outcome. */

pksize = (double) ceil(oms_dist_outcome (pksize_dist_ptr));

ceil返回大于或等于指定表达式的最小整数

/* Create a packet of specified formatand size.*/

if (generate_unformatted == OPC_TRUE)

{

/* We produce unformattedpackets. Create one. */

pkptr = op_pk_create(pksize);

}

else

{

/* Create a packet with the specifiedformat.*/

pkptr = op_pk_create_fmt(format_str);创建一个预定义结构的包，返回包格式

op_pk_total_size_set (pkptr,pksize); 设置包的大小

}

/* Update the packet generationstatistics. */

op_stat_write (packets_sent_hndl, 1.0);

op_stat_write (packets_sent_hndl, 0.0);

op_stat_write (bits_sent_hndl, (double)pksize);

op_stat_write (bits_sent_hndl, 0.0);

op_stat_write (packet_size_hndl,(double) pksize);

op_stat_write (interarrivals_hndl,next_intarr_time);

/* Send the packet via the stream tothe lower layer. */

op_pk_send (pkptr, SSC_STRM_TO_LOW);将包发送到输出包流中

FOUT;

}

generate状态的入口代码

/* At theenter execs of the "generate" state we schedule the */

/*arrival of the next packet. */

next_intarr_time= oms_dist_outcome (interarrival_dist_ptr);

/* Makesure that interarrival time is not negative. In that case it */

/* will beset to 0. */ 确定包生成的间隔时间是有效的

if(next_intarr_time <0)

{

next_intarr_time = 0;

}

next_pk_evh= op_intrpt_schedule_self (op_sim_time () + next_intarr_time, SSC_GENERATE);

generate的出口代码

/*Determine the code of the interrupt, which is used in evaluating */

/* statetransition conditions. */

intrpt_code= op_intrpt_code ();

stop状态的入口代码

/* Whenwe enter into the "stop" state, it is the time for us to */

/* stopgenerating traffic. We simply cancel the generation of the */

/* nextpacket and go into a silent mode by not scheduling anything */

/* else. */

if(op_ev_valid (next_pk_evh) == OPC_TRUE)

{

op_ev_cancel (next_pk_evh); 撤销事件

}

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