자꾸 발생하는 segmentation

#include <stdio.h>
#include <stdlib.h>
#include <pcap.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <netinet/ip.h>
//#include <netinet/if_ether.h>
#include <netinet/ether.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include <net/ethernet.h>
#include <time.h>
 
#include <qmessagebox.h>
#include <qlistbox.h>
#include <qlistview.h>
#include <qstring.h>
#include <qthread.h>
#include <qtextedit.h>
 
#define MAX_NUM		3
#define TIMEOUT		100
#define PROMISCUOUS		1
#define NONPROMISCUOUS	0
#define SNAPLEN		1024
#define PACKET_ARRAY_SIZE	10000
#define APLISTSIZE		15
 
//aThread threadA;			// object of thread
 
 
 
 
class aThread : public QThread{
public:
    aThread();
 
    void run();
    void stop();
 
    void set_ListBox(QListBox* lb);
    void set_ListView(QListView* lv, QListViewItem* lvi);
    void set_TextEdit(QTextEdit* te1, QTextEdit* te2);
 
    void set_capturing(void);
    void set_capturing(QString filterRule);
    void capturing();//pcap_t *pd,char *dev);
    void stop_capturing(void);
    void converter(unsigned char *ch);
 
    QString str, str_dinfo;
    QMessageBox *msg;
    QListBox* listBox1;
    QListViewItem* listViewItem1;
    QListView* listView1;
    QTextEdit *textEdit1, *textEdit2;
 
 
 
 
 
protected:
    struct packetBox{
	u_int pkt_len;
	u_char *pkt;
	int pcnt;
    };
    struct packetBox pb[100000];
 
 
private:    
    volatile bool stopped;
    char *dev;
    pcap_t *pd;
    int cnt;
    struct bpf_program fp;
 
    bpf_u_int32 netp,maskp;
 
    char errbuf[PCAP_ERRBUF_SIZE];
 
 
};
 
aThread::aThread(){
 
    int ret;		// get net info
 
    cnt=0;		// packet count
 
    stopped = false;
 
 
    // give device name to dev
    dev = (char*)malloc(sizeof(char)*6);
    strcpy(dev,"wlan0");
 
    // just do it for compile stage
    if( (ret = pcap_lookupnet(dev,&netp,&maskp,errbuf)) == -1){
	msg = new QMessageBox();
	msg->setText("ERROR");
	msg->show();
    }
}
void aThread::set_ListBox(QListBox* lb)
{    
    listBox1 = lb;
}
void aThread::set_ListView(QListView* lv, QListViewItem* lvi){
    listViewItem1 = lvi;
    listView1= lv;    
}
void aThread::set_TextEdit(QTextEdit* te1, QTextEdit* te2){
    textEdit1 = te1;
    textEdit2 = te2;    
}
 
void aThread::run(){
 
    while(!stopped){
	capturing();//pd, dev);
	usleep(100000);
    }
}
void aThread::stop(){
	stopped = true;
}
 
void aThread::stop_capturing(){
	pcap_close(pd);
}
 
void aThread::set_capturing(){
	if(pd){
		//stop_capturing();
	}
	usleep(10);
 
	pd = pcap_open_live(dev,SNAPLEN, PROMISCUOUS, TIMEOUT, errbuf);
}
 
void aThread::set_capturing(QString filterRule){
	if(pd){
		//stop_capturing();
	}usleep(10);
 
	pd = pcap_open_live(dev,SNAPLEN, PROMISCUOUS, TIMEOUT, errbuf);
 
	if(pcap_compile(pd,&fp, filterRule, 0, netp) == -1){
		stop_capturing();
		msg = new QMessageBox();
		msg->setText("Filter compile error!");
		msg->show();
	}
	if(pcap_setfilter(pd,&fp) == -1){
		stop_capturing();
		msg = new QMessageBox();
		msg->setText("set filter error!");
		msg->show();		
	}
}
 
void aThread::capturing()//pcap_t *pd,char *dev)
{
    unsigned char *p;
    struct pcap_pkthdr header;
 
    struct ether_header *ep;
 
    unsigned short ether_type;
 
    struct ip *iph;
    struct udphdr *udph;
    struct tcphdr *tcph;
    struct icmp *icmph;
    struct arphdr *arph;
    ///////////////////////////////////////////////////
    time_t my_time;
    struct tm *tm_ptr;
    int len=0;//,temp,chcnt;
 
 
    ///////////////////////////////////////////////////
    unsigned char *tcpdata, *udpdata, *icmpdata;//, temp_char;
 
 
    QString str_cnt, str_src, str_dst, str_prt, str_time ;
    QString str_hinfo,sub_info;
    QString str;
 
 
 
    str_dinfo.remove(0,str_dinfo.length());	// clear dataString to write at textEdit2
 
 
    cnt++; // captured packet count
    time(&my_time);
	while( (p = (unsigned char*)pcap_next(pd,&header)) == NULL){}
	tm_ptr = localtime(&my_time);
 
	QTextOStream(&str_time) << tm_ptr->tm_hour << ":"
		<<tm_ptr->tm_min << ":" << tm_ptr->tm_sec;
 
	ep = (struct ether_header *)p;
	p+=sizeof(struct ether_header);
 
	ether_type = ntohs(ep->ether_type);
 
	if(cnt<10){
	    QTextOStream(&str_cnt) << 0 << cnt;
	}
	else{
	    QTextOStream(&str_cnt) << cnt;	// captured packet count
	}
 
	if(ether_type == ETHERTYPE_IP){
 
	    iph = (struct ip*)p;	    
 
	    str_src = inet_ntoa(iph->ip_src);	// src ip
	    str_dst = inet_ntoa(iph->ip_dst);	// dst ip
 
	    // packet info
	    // QTextOStream(&str_hinfo) << ....;
	    if(iph->ip_p == IPPROTO_TCP){
 
		str_prt = "TCP";
 
		tcph = (struct tcphdr *)(p+iph->ip_hl*4);
		tcpdata = (unsigned char*)(p+(iph->ip_hl*4)+(tcph->doff*4));
		str_hinfo+="\n============ TCP HEADER =============\n";
		QTextOStream(&sub_info) << ....;
	    }
	    else if(iph->ip_p == IPPROTO_UDP){
		str_prt = "UDP";
 
		udph = (struct udphdr*)(p+iph->ip_hl*4);
		udpdata = (unsigned char*)(p+iph->ip_hl*4)+8;
		str_hinfo+="\n============ UDP HEADER =============\n";
		QTextOStream(&sub_info) << ....;
 
	    }
	    else if(iph->ip_p == IPPROTO_ICMP){
 
		str_prt = "ICMP";
 
		icmph = (struct icmp*)(p+iph->ip_hl*4);
		icmpdata = (unsigned char*)(p+iph->ip_hl*4)+8;
		str_hinfo+="\n============ ICMP HEADER =============\n";
		QTextOStream(&sub_info) << ....;
	    }
	    else if(iph->ip_p == IPPROTO_IGMP){
	    }
 
	}
	else if(ether_type == ETHERTYPE_ARP){
       	    str_prt = "ARP";
	    arph = (struct arphdr*)p;
 
	    // packet info
	    QTextOStream(&str_hinfo) << ....;
 
 
	    str_dst = "Broadcast";
    	    str_src = "NO Info";
 
 
	}
	else{
	    str_prt = "NON IP";
    	    str_src = "NON IP";
	    str_dst = "NON IP";	   
	}
	listViewItem1 = new QListViewItem(listView1, str_cnt,str_src,str_dst,str_prt,str_time);
	listView1->insertItem(listViewItem1);
 
	pb[cnt-1].pkt = (u_char*)malloc(sizeof(p));
	strcpy( (char*)pb[cnt-1].pkt ,(char*)p);
 
	if(cnt == 2){
 
	    while((unsigned char)len < header.len){
		converter(p++);
		if( (++len%16) == 0){
		    str_dinfo = str_dinfo.append("\n");
		}	
	    }
	    textEdit1->setText(str_hinfo+sub_info);
	    textEdit2->setText(str_dinfo);    
	}
}
void aThread::converter(unsigned char *ch){
	unsigned char mask = 0x0f;
	char val[4];
	int i;
 
	val[1] = *ch&mask;
	val[0] = *ch>>4;
 
	for(i=0;i<2;i++){
		val[i] %= 17;
		if( val[i]/10 ){ 
			val[i] += 87;
		}	// to start from 97
		else{ 
			val[i] += 48;
		}	// to start from 48
	}val[i]=' ';
	val[3]='\0';
 
	str_dinfo = str_dinfo.append(val);
}

#define PACKET_ARRAY_SIZE	10000
 
aThread threadA;
 
void form1::init(){
    setForm();
    setListBox();
 
    called = false;
    threadA.set_ListView(listView1,lv);
    threadA.set_TextEdit(textEdit1, textEdit2);
}
 
void form1::packetCapture()
{
    threadA.set_capturing();
 
    if( threadA.running() ){
	threadA.stop();
    }else{
	threadA.start();
    }
 
}