I am currently writing a small UDP server program in linux. The UDP server will receive packets from two different peers and will perform different operations based on from which peer it received the packet. I am trying to determine the source from where I receive the packet. However, when select returns and recvfrom is called, it returns with an error of Invalid Argument. If I pass NULL as the second last arguments, recvfrom succeeds.
I have tried declaring fromAddr as struct sockaddr_storage, struct sockaddr_in, struct sockaddr without any success. Is their something wrong with this code? Is this the correct way to determine the source of the packet?
The code snippet follows.
`
/*TODO : update for TCP. use recv */
if((pkInfo->rcvLen=recvfrom(psInfo->sockFd,
pkInfo->buffer,
MAX_PKTSZ,
0,
/* (struct sockaddr*)&fromAddr,*/
NULL,
&(addrLen)
)) < 0)
{
perror("RecvFrom failed\n");
}
else
{
/*Apply Filter */
#if 0
struct sockaddr_in* tmpAddr;
tmpAddr = (struct sockaddr_in* )&fromAddr;
printf("Received Msg From %s\n",inet_ntoa(tmpAddr->sin_addr));
#endif
printf("Packet Received of len = %d\n",pkInfo->rcvLen);
}
`
