Messages in this thread | | | From | "Paul D. Smith" <> | Date | Thu, 1 Feb 2001 21:02:36 -0500 | Subject | Re: SO_REUSEADDR redux |
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%% Alan Cox <alan@lxorguk.ukuu.org.uk> writes:
>> This application uses SO_REUSEADDR in conjunction with INADDR_ANY. What >> it does is bind() to INADDR_ANY, then listen(). Then, it proceeds to >> bind (but _not_ listen) various other specific addresses.
ac> That should be ok if its setting SO_REUSEADDR
I agree, and so does Solaris/FreeBSD, but Linux doesn't. See below for a test program. Maybe I'm doing something screwed up.
-------------------------8>< snip ><8------------------------- #include <stdio.h> #include <errno.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h>
#define MY_PORT 10000
int main(int argc, char *argv[]) { int any_fd, this_fd; int val = 1; struct sockaddr_in addr;
if ((any_fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 || fcntl(any_fd, F_SETFL, O_NONBLOCK) < 0 || setsockopt(any_fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof val) < 0) { perror("setup(any)"); return 1; }
if ((this_fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 || fcntl(this_fd, F_SETFL, O_NONBLOCK) < 0 || setsockopt(this_fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof val) < 0) { perror("setup(this)"); return 1; }
addr.sin_family = AF_INET; addr.sin_port = MY_PORT; memset(addr.sin_zero, 0, sizeof (addr.sin_zero));
addr.sin_addr.s_addr = INADDR_ANY;
if (bind(any_fd, (struct sockaddr *)&addr, sizeof (addr)) < 0) { perror("bind(any)"); return 1; }
if (listen(any_fd, 10) < 0) { perror("listen(any)"); return 1; }
addr.sin_addr.s_addr = INADDR_LOOPBACK;
if (bind(this_fd, (struct sockaddr *)&addr, sizeof (addr)) < 0) { perror("bind(this)"); return 1; }
return 0; } -------------------------8>< snip ><8-------------------------
solaris$ gcc -o reuseaddr{,.c} -lsocket -lnsl solaris$ ./reuseaddr
Works. Now:
linux$ gcc -o reuseaddr{,.c} linux$ ./reuseaddr bind(this): Cannot assign requested address
:( The real code doesn't use LOOPBACK, of course.
This is Linux 2.2.17, but I tried with 2.2.18 too. I haven't tried 2.4.x.
Thanks...
-- ------------------------------------------------------------------------------- Paul D. Smith <psmith@baynetworks.com> HASMAT--HA Software Methods & Tools "Please remain calm...I may be mad, but I am a professional." --Mad Scientist ------------------------------------------------------------------------------- These are my opinions---Nortel Networks takes no responsibility for them. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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