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* resolv/resolv.h (RES_SNGLKUP): Define.

Browse Source 
* resolv/res_init.c (res_setoptions): Recognize single-request option.
	* resolv/res_send.c (send_dg): If we sent two requests at once and
	only get one reply before timeout switch to mode where we send the
	second request only after the first answer has been received.
This commit is contained in:
Ulrich Drepper
2009-04-07 02:00:27 +00:00
parent 735be40014
commit ae06191038
4 changed files with 38 additions and 11 deletions
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37
resolv/res_send.c
View File

@@ -923,12 +923,12 @@ send_dg(res_state statp,
struct pollfd pfd[1];
int ptimeout;
struct sockaddr_in6 from;
int resplen, seconds, n;
int resplen, n;
if (EXT(statp).nssocks[ns] == -1) {
/* only try IPv6 if IPv6 NS and if not failed before */
if ((EXT(statp).nscount6 > 0) && !statp->ipv6_unavail) {
if (__have_o_nonblock >= 0) {
if (__builtin_expect (__have_o_nonblock >= 0, 1)) {
EXT(statp).nssocks[ns] =
socket(PF_INET6, SOCK_DGRAM|SOCK_NONBLOCK,
0);
@@ -939,7 +939,7 @@ send_dg(res_state statp,
&& errno == EINVAL ? -1 : 1);
#endif
}
if (__have_o_nonblock < 0)
if (__builtin_expect (__have_o_nonblock < 0, 0))
EXT(statp).nssocks[ns] =
socket(PF_INET6, SOCK_DGRAM, 0);
if (EXT(statp).nssocks[ns] < 0)
@@ -950,7 +950,7 @@ send_dg(res_state statp,
convaddr4to6(nsap);
}
if (EXT(statp).nssocks[ns] < 0) {
if (__have_o_nonblock >= 0) {
if (__builtin_expect (__have_o_nonblock >= 0, 1)) {
EXT(statp).nssocks[ns]
= socket(PF_INET, SOCK_DGRAM|SOCK_NONBLOCK,
0);
@@ -961,7 +961,7 @@ send_dg(res_state statp,
&& errno == EINVAL ? -1 : 1);
#endif
}
if (__have_o_nonblock < 0)
if (__builtin_expect (__have_o_nonblock < 0, 0))
EXT(statp).nssocks[ns]
= socket(PF_INET, SOCK_DGRAM, 0);
}
@@ -989,7 +989,7 @@ send_dg(res_state statp,
__res_iclose(statp, false);
return (0);
}
if (__have_o_nonblock < 0) {
if (__builtin_expect (__have_o_nonblock < 0, 0)) {
/* Make socket non-blocking. */
int fl = __fcntl (EXT(statp).nssocks[ns], F_GETFL);
if (fl != -1)
@@ -1003,11 +1003,14 @@ send_dg(res_state statp,
/*
* Compute time for the total operation.
*/
seconds = (statp->retrans << ns);
int seconds = (statp->retrans << ns);
if (ns > 0)
seconds /= statp->nscount;
if (seconds <= 0)
seconds = 1;
bool single_request = ((statp->options) & RES_SNGLKUP) != 0;// XXX
int save_gotsomewhere = *gotsomewhere;
retry:
evNowTime(&now);
evConsTime(&timeout, seconds, 0);
evAddTime(&finish, &now, &timeout);
@@ -1031,6 +1034,7 @@ send_dg(res_state statp,
return (0);
}
evSubTime(&timeout, &finish, &now);
need_recompute = 0;
}
/* Convert struct timespec in milliseconds. */
ptimeout = timeout.tv_sec * 1000 + timeout.tv_nsec / 1000000;
@@ -1046,8 +1050,16 @@ send_dg(res_state statp,
Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
if (resplen > 1 && (recvresp1 || (buf2 != NULL && recvresp2)))
{
*resplen2 = 1;
return resplen;
/* There are quite a few broken name servers out
there which don't handle two outstanding
requests from the same source. There are also
broken firewall settings. If we time out after
having received one answer switch to the mode
where we send the second request only once we
have received the first answer. */
single_request = true;
*gotsomewhere = save_gotsomewhere;
goto retry;
}
*gotsomewhere = 1;
@@ -1073,7 +1085,7 @@ send_dg(res_state statp,
Perror(statp, stderr, "send", errno);
goto err_out;
}
if (nwritten != 0 || buf2 == NULL)
if (nwritten != 0 || buf2 == NULL || single_request)
pfd[0].events = POLLIN;
else
pfd[0].events = POLLIN | POLLOUT;
@@ -1286,8 +1298,11 @@ send_dg(res_state statp,
else
recvresp2 = 1;
/* Repeat waiting if we have a second answer to arrive. */
if ((recvresp1 & recvresp2) == 0)
if ((recvresp1 & recvresp2) == 0) {
if (single_request)
pfd[0].events = POLLOUT;
goto wait;
}
/*
* All is well, or the error is fatal. Signal that the
* next nameserver ought not be tried.