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authorDenys Vlasenko <vda.linux@googlemail.com>2010-02-03 00:11:34 +0100
committerDenys Vlasenko <vda.linux@googlemail.com>2010-02-03 00:11:34 +0100
commitcca45baf8353d1e338d232f5bdb2d1d6b357f1da (patch)
tree171473d75c56dc718c1fde6f27cbbd30109b7d13 /libc/inet/resolv.c
parent1043d24e77f82d729996fe8192b078e567b16113 (diff)
/etc/resolv.conf: support "timeout:n" and "attempts:n" options
text data bss dec hex filename - 1745 2 4 1751 6d7 libc/inet/dnslookup.o + 1760 2 4 1766 6e6 libc/inet/dnslookup.o - 962 0 4 966 3c6 libc/inet/opennameservers.o + 1099 0 4 1103 44f libc/inet/opennameservers.o - 462 4 472 938 3aa libc/inet/res_init.o + 454 4 468 926 39e libc/inet/res_init.o - 870 0 0 870 366 libc/inet/res_query.o + 867 0 0 867 363 libc/inet/res_query.o Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'libc/inet/resolv.c')
-rw-r--r--libc/inet/resolv.c54
1 files changed, 41 insertions, 13 deletions
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index ee1323e76..0a6fd7aaf 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -407,6 +407,8 @@ __UCLIBC_MUTEX_EXTERN(__resolv_lock);
/* Protected by __resolv_lock */
extern void (*__res_sync)(void) attribute_hidden;
/*extern uint32_t __resolv_opts attribute_hidden; */
+extern uint8_t __resolv_timeout attribute_hidden;
+extern uint8_t __resolv_attempts attribute_hidden;
extern unsigned __nameservers attribute_hidden;
extern unsigned __searchdomains attribute_hidden;
extern sockaddr46_t *__nameserver attribute_hidden;
@@ -499,7 +501,7 @@ extern void __close_nameservers(void) attribute_hidden;
* Allows addresses returned by gethostbyname to be sorted.
* Not supported.
* options option[ option]...
- * (so far we support none)
+ * (so far we support timeout:n and attempts:n)
* $RES_OPTIONS (space-separated list) is to be added to "options"
* debug sets RES_DEBUG in _res.options
* ndots:n how many dots there should be so that name will be tried
@@ -526,7 +528,7 @@ extern void __close_nameservers(void) attribute_hidden;
*
* We will read and analyze /etc/resolv.conf as needed before
* we do a DNS request. This happens in __dns_lookup.
- * (TODO: also re-parse it after a timeout, to catch updates).
+ * It is reread if its mtime is changed.
*
* BSD has res_init routine which is used to initialize resolver state
* which is held in global structure _res.
@@ -903,6 +905,8 @@ __UCLIBC_MUTEX_INIT(__resolv_lock, PTHREAD_MUTEX_INITIALIZER);
/* Protected by __resolv_lock */
void (*__res_sync)(void);
/*uint32_t __resolv_opts; */
+uint8_t __resolv_timeout;
+uint8_t __resolv_attempts;
unsigned __nameservers;
unsigned __searchdomains;
sockaddr46_t *__nameserver;
@@ -970,6 +974,9 @@ void attribute_hidden __open_nameservers(void)
if (__nameservers)
goto sync;
+ __resolv_timeout = RES_TIMEOUT;
+ __resolv_attempts = RES_DFLRETRY;
+
fp = fopen("/etc/resolv.conf", "r");
#ifdef FALLBACK_TO_CONFIG_RESOLVCONF
if (!fp) {
@@ -1048,7 +1055,24 @@ void attribute_hidden __open_nameservers(void)
continue;
}
/* if (strcmp(keyword, "sortlist") == 0)... */
- /* if (strcmp(keyword, "options") == 0)... */
+ if (strcmp(keyword, "options") == 0) {
+ char *p1;
+ uint8_t *what;
+
+ if (p == NULL || (p1 = strchr(p, ':')) == NULL)
+ continue;
+ *p1++ = '\0';
+ if (p1 == NULL)
+ continue;
+ if (strcmp(p, "timeout") == 0)
+ what = &__resolv_timeout;
+ else if (strcmp(p, "attempts") == 0)
+ what = &__resolv_attempts;
+ else
+ continue;
+ *what = atoi(p1);
+ DPRINTF("option %s:%d\n", p, *what);
+ }
}
fclose(fp);
}
@@ -1285,8 +1309,7 @@ int attribute_hidden __dns_lookup(const char *name,
local_ns_num = 0;
if (_res.options & RES_ROTATE) */
local_ns_num = last_ns_num;
-/*TODO: use _res.retry */
- retries_left = __nameservers * RES_DFLRETRY;
+ retries_left = __nameservers * __resolv_attempts;
}
retries_left--;
if (local_ns_num >= __nameservers)
@@ -1345,8 +1368,7 @@ int attribute_hidden __dns_lookup(const char *name,
send(fd, packet, packet_len, 0);
#ifdef USE_SELECT
-/*TODO: use _res.retrans*/
- reply_timeout = RES_TIMEOUT;
+ reply_timeout = __resolv_timeout;
wait_again:
FD_ZERO(&fds);
FD_SET(fd, &fds);
@@ -1360,7 +1382,7 @@ int attribute_hidden __dns_lookup(const char *name,
}
reply_timeout--;
#else
- reply_timeout = RES_TIMEOUT * 1000;
+ reply_timeout = __resolv_timeout * 1000;
wait_again:
fds.fd = fd;
fds.events = POLLIN;
@@ -2878,6 +2900,8 @@ static void res_sync_func(void)
__nameserver[n].sa4 = rp->nsaddr_list[n]; /* struct copy */
#endif
}
+ __resolv_timeout = rp->retrans;
+ __resolv_attempts = rp->retry;
/* Extend and comment what program is known
* to use which _res.XXX member(s).
@@ -2904,13 +2928,17 @@ int res_init(void)
memset(rp, 0, sizeof(*rp));
rp->options = RES_INIT;
-#ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
rp->retrans = RES_TIMEOUT;
- rp->retry = 4;
-/*TODO: pulls in largish static buffers... use simpler one? */
- rp->id = random();
-#endif
+ rp->retry = RES_DFLRETRY;
rp->ndots = 1;
+#ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
+ /* Was: "rp->id = random();" but:
+ * - random() pulls in largish static buffers
+ * - isn't actually random unless, say, srandom(time(NULL)) was called
+ * - is not used by uclibc anyway :)
+ */
+ /* rp->id = 0; - memset did it */
+#endif
#ifdef __UCLIBC_HAS_EXTRA_COMPAT_RES_STATE__
rp->_vcsock = -1;
#endif