hi there
i have a linked list content another linked list. which is something like: -
struct nodebranch{
-
unsigned int offset;
-
unsigned char data[130];
-
struct nodebranch *next;
-
};
-
-
struct node{
-
unsigned int id;
-
struct nodebranch *branch;
-
struct node *next;
-
};
-
what i need to do is, search the list, find the node with same id, and insert the packet into the branch of that id with sorted order.
so i have a function called insertToList(struct node **msgBuffer, L2_IDU l2idu)
and a function insertToBranch(struct nodebranch **bufferNode, L2_IDU l2idu)
the insertToBranch will be called in insertToList. insertToList basiclly check if the id match node, if yes, call insertToBranch(), not, add node and call insertToBranch()
here is how i call insertToBranch() from inserToList() -
/*case 1, there s a node in the list have same id */
-
if(currentList != NULL && preList!=NULL){
-
-
/* insert the packet into the node */
-
insertToBranch(&(currentList->branch), l2idu);
-
}
-
and it worked all fine untill when i get into isertToBranch(), when i trying to point a current pointer to the node. part of the code is -
void insertToBranch(struct nodebranch **bufferNode, L2_IDU l2idu){
-
-
printf("in the insertToBranch function\n");
-
int offset; /* the offset of incoming packet l2idu*/
-
int i; /* counter i */
-
int length; /* totle length of the packet */
-
int lastPacketDataLength = 0; /* the data length of the last packet(where MP=0)*/
-
struct nodebranch * newNode; /* newNode to add into branch */
-
struct nodebranch * pre; /* a linked list point one node before current*/
-
struct nodebranch * current;
-
-
/* current point to bufferNode */
-
current = *bufferNode;
-
-
i think there s something wrong with the pointer reference been carried to the insertToBranch(). but not sure. i know it looks very messy. shoot me questions if u dont get it. and sorry i cant give all the code since they r HUGE.
ps. yes, i have to use linked list of linked list, since i need carefully watch the memory for my program.
cheers
dave
3 1495
hi!
could you upload your file or send it to my e-mail alnbras@gmail.com
I can't understand your code completely...
I hope I can help u
is there any space i can upload my files here? i have about eight files for this project, so i dont know if i should upload them all.
but here is the file i have problem with. -
-
#include <stdio.h>
-
#include <stdlib.h>
-
#include <unistd.h>
-
-
#include "bool.h"
-
#include "layer2.h"
-
#include "layer3.h"
-
-
/* The Layer 3 PDU length is the MTU of Layer 3. */
-
/* (even though we can't really put all that into one packet) */
-
#define L3_PDU_MAXLENGTH L3_MTU
-
-
/* the fill in for other headers which need to be set to zero*/
-
#define ZERO 0x00;
-
-
/* a global varible for identification */
-
static int identificator = 0;
-
-
-
/* the branch linked list */
-
struct nodebranch{
-
unsigned int offset;
-
unsigned char data[130];
-
struct nodebranch *next;
-
};
-
-
struct node{
-
unsigned int id;
-
struct nodebranch *branch;
-
struct node *next;
-
};
-
-
/* the linked list we use to store different msgs before send them*/
-
static void insertToList(struct node **msgBuffer, L2_IDU l2idu);
-
static void insertToBranch(struct nodebranch **bufferNode, L2_IDU l2idu);
-
static int countLength(struct nodebranch **branch);
-
-
/* the function to check if all the packets have been stored, if is
-
* sort and send the msg and return a 1, else return 0
-
*/
-
void StoreAndSendMessage(struct nodebranch * branch, int branchLength, int lastPacketDataLength);
-
-
void checkAndSend(struct nodebranch **branch, L2_IDU l2idu);
-
-
//void insert( NodePtr *sPtr, char value);
-
//void delete( NodePtr *sPtr, char value);
-
-
/* the packet is a Layer 3 protocol data unit */
-
typedef unsigned char L3_PDU[L3_PDU_MAXLENGTH];
-
-
int L3_connected=FALSE;
-
-
/* the function that Layer 2 calls */
-
static void L3_receiveL2_IDU(L2_IDU l2idu);
-
-
/* the pointer to a function, to call when giving a DU to Layer 4 */
-
static void (* receiveL3_IDU)(L3_IDU l3idu);
-
-
/**
-
* Place your function header and description here.
-
* - describe how you implemented the reassembly
-
* - describe any data structures you used
-
* - etc.
-
*/
-
static void L3_receiveL2_IDU(L2_IDU l2idu)
-
{
-
/* the linked list of linked list which store all the packets
-
* before sending them
-
*/
-
printf("show something before the seg fault!!\n");
-
struct node *msgBuffer = NULL;
-
-
insertToList(&msgBuffer, l2idu);
-
}
-
-
void insertToList(struct node **Buffer, L2_IDU l2idu){
-
-
int id; /* identification */
-
/* check if the linked list already have node with the same
-
* identificaton
-
*/
-
struct node *currentList; /*currentListList pointer*/
-
struct node *new; /*use to add new node*/
-
struct node *preList; /*point to one before msgBuffer*/
-
-
/*allocate memory to new*/
-
new = malloc(sizeof(struct node));
-
-
/* get id */
-
id = ((l2idu.data[4]<<8) | l2idu.data[5]);
-
-
/* if there s space, insert packet*/
-
if(new != NULL){
-
-
preList = NULL;
-
currentList = *Buffer;
-
-
/* loop to the last node in the list or the node which got
-
* the same id no. with the packet*/
-
while(currentList != NULL && currentList->id != id){
-
preList = currentList;
-
currentList = currentList->next;
-
}
-
/*case 1, there s a node in the list have same id */
-
if(currentList != NULL && preList!=NULL){
-
-
/* insert the packet into the node */
-
insertToBranch(&(currentList->branch), l2idu);
-
printf("out of insertToBranch function01");
-
-
}
-
/* otherwise, the list comes to the end, and we ll add the packet
-
* on the end of the list*/
-
else{
-
new->id = id;
-
insertToBranch(&(currentList->branch), l2idu);
-
printf("out of insertToBranch function02");
-
new->next = NULL; /*node doesnt link to other node*/
-
-
/* case 3, empty list */
-
if (preList == NULL){
-
new->next = *Buffer;
-
*Buffer = new;
-
/* point currentList to new */
-
currentList = new;
-
}
-
/* case 2, no id in the list, add to the end of list */
-
else {
-
preList->next = new;
-
new->next = currentList;
-
/* point currentList to new */
-
currentList = new;
-
}
-
}
-
}
-
else {
-
printf("%c not inserted. No memory available.\n", id );
-
}
-
-
/* after insert the packet, we need to check if the branch which
-
* just insert the packet has a MF set to true. if its true, means
-
* there s chance the whole msg has been recieved. if its so, store
-
* and send the msg, and clear the branch free the memory.
-
*/
-
checkAndSend(¤tList->branch, l2idu);
-
-
if(currentList->branch == NULL){
-
preList->next = currentList->next;
-
free(currentList);
-
}
-
}
-
-
-
-
/*insert the packet into the node with same id, along
-
* with data, a offset and a counter will be saved as well
-
* for later use. after the packet has been saved onto branch,
-
* check if all the packets has been recieved, by check if
-
* the count equl to the offset/16. sort and send them and
-
* make branch to NULL and free the memory.
-
* the packet with MF = 0 (the last packet) will be inserted
-
* on the end of the list while others will be inserted in the
-
* front.
-
*/
-
void insertToBranch(struct nodebranch **bufferNode, L2_IDU l2idu){
-
-
printf("in the insertToBranch function\n");
-
int offset; /* the offset of incoming packet l2idu*/
-
int i; /* counter i */
-
int length; /* totle length of the packet */
-
int lastPacketDataLength = 0; /* the data length of the last packet(where MP=0)*/
-
struct nodebranch * newNode; /* newNode to add into branch */
-
struct nodebranch * pre; /* a linked list point one node before current*/
-
struct nodebranch * current;
-
-
/* current point to bufferNode */
-
current = *bufferNode;
-
-
/* get the offset, while the MF is 1, need to change that bit
-
* into 0 1st.
-
*/
-
-
printf("the current is pointed to *bufferNode\n");
-
if( (l2idu.data[6] ^ (1<<5)) > l2idu.data[6]){
-
offset = ((l2idu.data[6]<<8) | l2idu.data[7]);
-
printf("the offset is : %d \n", offset);
-
}
-
else {
-
offset = ( ( (l2idu.data[6] ^ (1<<5)) <<8) | l2idu.data[7]);
-
printf("the offset is : %d \n", offset);
-
}
-
-
/* get totle length of the packet */
-
length = ((l2idu.data[2]<<8) | l2idu.data[3]);
-
-
/* asign memory to the new node */
-
newNode = malloc(sizeof(struct nodebranch));
-
-
/*if the MF = 0, the bufferNode->MF will be set to TRUE
-
*/
-
if((l2idu.data[6] ^ (1<<5)) > l2idu.data[6]) {
-
-
/* the data length of packet which have MF=0 */
-
lastPacketDataLength = length - 20;
-
}
-
/* for all the packets, will be inserted into a sorted list */
-
/* loop to get the sorted position of the packet */
-
while(current != NULL && offset > current->offset){
-
pre = current;
-
current = current->next;
-
}
-
-
/* put packet into a new node */
-
newNode->offset = offset;
-
for(i=0; i<(length-20); i++){
-
newNode->data[i] = l2idu.data[20+i];
-
}
-
-
/* for empty list */
-
if(pre == NULL){
-
newNode->next = *bufferNode;
-
*bufferNode = newNode;
-
}
-
/* if list s not empty, insert new node */
-
else{
-
pre->next = newNode;
-
newNode->next = current;
-
}
-
}
-
-
-
-
void checkAndSend(struct nodebranch **branch, L2_IDU l2idu){
-
-
int i;
-
int count = 0;
-
int branchLength;
-
int lastPacketLength;
-
int lastPacketOffset;
-
struct nodebranch *pre;
-
struct nodebranch *currentCheck;
-
L3_IDU l3idu;
-
-
/* point current to branch*/
-
/*********************************************************************/
-
/*THIS IS THE PART CAUSE SEG FAULT(I THINK) */
-
currentCheck = *branch;
-
/*********************************************************************/
-
-
/* check the length of the branch */
-
branchLength = countLength(&*branch);
-
-
/* get the last node(MF = 0)'s offset */
-
while(currentCheck->next != NULL){
-
pre = currentCheck;
-
currentCheck = currentCheck->next;
-
}
-
lastPacketOffset = currentCheck->offset;
-
-
lastPacketLength = countLength(¤tCheck);
-
-
/*compare the banch length with lastPackOffset/16 see if all the packets has been
-
* received */
-
if(branchLength == lastPacketOffset/16){
-
-
/* store the msg into l3idu */
-
l3idu.length = (branchLength - 1)*128 + lastPacketLength;
-
-
/*store the data, since they already been sorted in order, so just go node
-
* by node, and store them into l3idu. */
-
while(currentCheck->next != NULL){
-
-
for(i=0; i<128; i++){
-
l3idu.data[i + (count*128)] = currentCheck->data[i];
-
}
-
pre->next = currentCheck;
-
currentCheck = currentCheck->next;
-
free(pre);
-
count++;
-
}
-
/* it come to the last node, which have MF=0 and data length from 1 to 130*/
-
for(i=0; i<lastPacketLength; i++){
-
l3idu.data[i + (count * 128)] = currentCheck->data[i];
-
}
-
free(currentCheck);
-
-
receiveL3_IDU(l3idu);
-
}
-
}
-
-
-
-
int countLength(struct nodebranch **branch){
-
-
int counter = 0;
-
struct nodebranch * countlength = *branch;
-
-
while(countlength != NULL){
-
counter++ ;
-
countlength = countlength->next;
-
}
-
return counter;
-
}
-
-
-
/*******************************************************************************
-
YOU DON'T NEED TO MODIFY ANY CODE BENEATH THIS POINT
-
The following code will not be read during marking.
-
*******************************************************************************/
-
-
void L3_callback(void (*func)(L3_IDU l3idu))
-
{
-
receiveL3_IDU = func;
-
}
-
-
void L3_connectToPeerDevice(const char *hostname, int port)
-
{
-
/* establish connection to vhub, etc. */
-
L2_connectToPeerDevice(hostname, port);
-
-
/* since Layer 1 terminates if can't connect, then assume connected */
-
L3_connected=TRUE;
-
-
/* set the call back function for receiving bytes from Layer 2 */
-
L2_callback(L3_receiveL2_IDU);
-
-
}
-
-
void L3_disconnectFromPeerDevice(void)
-
{
-
L2_disconnectFromPeerDevice();
-
-
/* since Layer 1 terminates if can't disconnect, then assume disconnected */
-
L3_connected=FALSE;
-
}
-
-
-
have a look into function insertToList and insertToBranch, i think the line cause seg fault is in insertToBranch.
thanks
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