Hi guys!
I have LINUX 6.0 with kernel 2.2.15 and installed SPX protocol (module
af_spx.o).
This module was loaded using utility insmod.
Using this feature i was create two programs: for server and for client.
Listing below
SERVER
#include <stdio.h>
#include <sys/types.h>
#include <netipx/ipx.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <errno.h>
int main(int argc,char** argv){
struct sockaddr_ipx sa_ipx;
int sock2;
int len=sizeof(sa_ipx);
int sock=socket(PF_IPX,SOCK_SEQPACKET,PF_IPX);
sa_ipx.sipx_family = AF_IPX;
sa_ipx.sipx_network = 0;
sa_ipx.sipx_port = htons(0x8003);
sa_ipx.sipx_type = 5;
if(bind(sock,(struct sockaddr *)&sa_ipx,len)==-1){
perror("Error bind");
exit(3);
}
if(listen(sock,1)==-1){
perror("Error listen");
exit(3);
}
if((sock2=accept(sock,(struct sockaddr *)&sa_ipx,&len))<0){
perror("Error accept");
exit(3);
}
shutdown(sock,2);
printf("Connected from %08lX:%02X%02X%02X%02X%02X%02X:%04X\n",
htonl(sa_ipx.sipx_network),
sa_ipx.sipx_node[0], sa_ipx.sipx_node[1],
sa_ipx.sipx_node[2], sa_ipx.sipx_node[3],
sa_ipx.sipx_node[4], sa_ipx.sipx_node[5],
htons(sa_ipx.sipx_port));
....
shutdown(sock2,2);
return 0;
}
CLIENT
#include <stdio.h>
#include <sys/types.h>
#include <netipx/ipx.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <errno.h>
int main(int argc,char** argv){
int result;
struct sockaddr_ipx sa_ipx;
int len=sizeof(sa_ipx);
int sock=socket(PF_IPX,SOCK_SEQPACKET,PF_IPX);
sa_ipx.sipx_family = AF_IPX;
sa_ipx.sipx_network = 0;
sa_ipx.sipx_port = 0;
sa_ipx.sipx_type = 5;
if(bind(sock,(struct sockaddr *)&sa_ipx,len)==-1){
perror("Error bind");
exit(3);
}
result = getsockname(sock, (struct sockaddr *)&sa_ipx, &len);
if (result < 0) {
perror("SPX: getsockname: ");
exit(3);
}
sa_ipx.sipx_port = htons(0x8003);
if(connect(sock,(struct sockaddr *)&sa_ipx,len)<0) {
perror("SPX: connect: ");
exit(3);
}
printf("Connected to %08lX:%02X%02X%02X%02X%02X%02X:%04X\n",
htonl(sa_ipx.sipx_network),
sa_ipx.sipx_node[0], sa_ipx.sipx_node[1],
sa_ipx.sipx_node[2], sa_ipx.sipx_node[3],
sa_ipx.sipx_node[4], sa_ipx.sipx_node[5],
htons(sa_ipx.sipx_port));
.....
shutdown(sock,2);
return 0;
}
Both programs running on the same machine (with LINUX OS).
After established spx connection on the screen occurs message from kernel:
UNABLE TO HANDLE KERNEL NULL POINTER DEREFERENCE
AT VIRTUAL ADDRESS 00000030
...
PROCESS SPX...
STACK...
CALL TRACE...
SEGMENTATION FAUL
In file /usr/src/linux/net/ipx/af_spx.c present function spx_accept. This
function contains follow rows:
217: sk = sock->sk;
......
......
254: sock->sk = null;
255: sk->ack_backlog--;
Variable <sk> is pointer to structure <sock>.On my mind asiign to pointer
null and after working
with pointer - it's greatest mistake and such program can't work right.
Because i changed places line 254 and line 255
And now
254: sk->ack_backlog--;
255: sock->sk = null;
However, this action don't help me. Probably the driver(af_spx.c) have some
more errors which i can't find.
And consequently I ask help if there is such opportunity.
Beforehand is grateful
With best regards
Rodion Matvienko
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