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Stop returning an error after successful send of zero length UDP packets

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A zero-length send is invalid with TCP, but well defined with UDP.
udp:send"" was returning (nil,"refused"), indicating that it failed when
the packet was actually sent. The test script reproduces the bug, and
includes a tcpdump of the zero length packet being sent.
This commit is contained in:
Sam Roberts 2011-06-17 13:51:34 -07:00
parent a8b19e5367
commit 51acb54760
2 changed files with 30 additions and 6 deletions
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11
src/usocket.c
View File

@ -213,14 +213,13 @@ int socket_send(p_socket ps, const char *data, size_t count,
for ( ;; ) {
long put = (long) send(*ps, data, count, 0);
/* if we sent anything, we are done */
if (put > 0) {
if (put >= 0) {
*sent = put;
return IO_DONE;
}
err = errno;
/* send can't really return 0, but EPIPE means the connection was
closed */
if (put == 0 || err == EPIPE) return IO_CLOSED;
/* EPIPE means the connection was closed */
if (err == EPIPE) return IO_CLOSED;
/* we call was interrupted, just try again */
if (err == EINTR) continue;
/* if failed fatal reason, report error */
@ -243,12 +242,12 @@ int socket_sendto(p_socket ps, const char *data, size_t count, size_t *sent,
if (*ps == SOCKET_INVALID) return IO_CLOSED;
for ( ;; ) {
long put = (long) sendto(*ps, data, count, 0, addr, len);
if (put > 0) {
if (put >= 0) {
*sent = put;
return IO_DONE;
}
err = errno;
if (put == 0 || err == EPIPE) return IO_CLOSED;
if (err == EPIPE) return IO_CLOSED;
if (err == EINTR) continue;
if (err != EAGAIN) return err;
if ((err = socket_waitfd(ps, WAITFD_W, tm)) != IO_DONE) return err;

25
test/udp-zero-length-send Executable file
View File

@ -0,0 +1,25 @@
#!/usr/bin/lua
--[[
Show that luasocket returns an error message on zero-length UDP sends,
even though the send is valid, and in fact the UDP packet is sent
to the peer:
% sudo tcpdump -i lo -n
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes
13:40:16.652808 IP 127.0.0.1.56573 > 127.0.0.1.5432: UDP, length 0
]]
require"socket"
s = assert(socket.udp())
r = assert(socket.udp())
assert(r:setsockname("*", 5432))
assert(s:setpeername("127.0.0.1", 5432))
ssz, emsg = s:send("")
print(ssz == 0 and "OK" or "FAIL",[[send:("")]], ssz, emsg)