UDP programming - set local listening port

[Rendering]

Hi, I am interested in a variant of question posted in this locked topic:
UDP programming - set local port
I am programming a network software that sends file using UDP protocol. I have some dubts about how to let the server listen to a specific port while cycling recevfrom()
I think this can be done with bind function, am I right? THX

[ssharish2005]

Well yes you would create a UDP socket first and bind that socket with the socket information after initialisng the structure. Something like as follow

struct sockaddr_in my_sock;

if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP))==-1)
    exit(1);

memset((char *) &si_me, 0, sizeof(my_sock));
my_sock.sin_family = AF_INET;
my_sock.sin_port = htons(PORT);
my_sock.sin_addr.s_addr = htonl(INADDR_ANY);

if (bind(s, &my_sock, sizeof(my_sock))==-1)
  exit(1);

ssharish

[Rendering]

I have another question: in server-side code, should I specify the machine ip address where server is running? This line of code

my_sock.sin_addr.s_addr = htonl(INADDR_ANY);

specifies that the packets can come from any address? From GAPIL book I can read:

struct sockaddr_in {
sa_family_t  sin_family ;  /* address family : AF_INET */ 
in_port_t  sin_port ;  /* port in network byte order */
struct in_addr sin_addr ;  /* internet address */ 
};
 /* Internet address . */
struct in_addr {
in_addr_t  s_addr ;  /* address in network byte order */
};

Thank you for your time

[ssharish2005]

No not necessarly. The INADDR_ANY will take the default ip address of your machine and tryied to assign it. If you need to assign a specific ip address yes you can.

ssharish