[git commit master] dnsd: add -s option. This allows (clumsy) operation with read dns servers
Denys Vlasenko
vda.linux at googlemail.com
Sun Feb 7 01:45:03 UTC 2010
commit: http://git.busybox.net/busybox/commit/?id=343dfd7abe44a32b329379ec9039f2560543518d
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
function old new delta
packed_usage 26816 26886 +70
dnsd_main 1299 1303 +4
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
include/usage.h | 7 ++++-
networking/dnsd.c | 73 ++++++++++++++++++++++++++++------------------------
2 files changed, 45 insertions(+), 35 deletions(-)
diff --git a/include/usage.h b/include/usage.h
index 109a35d..c2ffb6d 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -893,7 +893,7 @@
"\n -s SIZE Buffer size" \
#define dnsd_trivial_usage \
- "[-c CONFFILE] [-t TTL_SEC] [-p PORT] [-i ADDR] [-d]"
+ "[-dvs] [-c CONFFILE] [-t TTL_SEC] [-p PORT] [-i ADDR]"
#define dnsd_full_usage "\n\n" \
"Small static DNS server daemon\n" \
"\nOptions:" \
@@ -902,6 +902,11 @@
"\n -p PORT Listen on PORT" \
"\n -i ADDR Listen on ADDR" \
"\n -d Daemonize" \
+ "\n -v Verbose" \
+ "\n -s Send successful replies only. Use this if you want" \
+ "\n to use /etc/resolv.conf with two nameserver lines:" \
+ "\n nameserver DNSD_SERVER" \
+ "\n nameserver NORNAL_DNS_SERVER" \
#define dos2unix_trivial_usage \
"[OPTIONS] [FILE]"
diff --git a/networking/dnsd.c b/networking/dnsd.c
index 42deb1f..e73e244 100644
--- a/networking/dnsd.c
+++ b/networking/dnsd.c
@@ -56,7 +56,8 @@ struct dns_entry {
char name[1];
};
-#define OPT_verbose (option_mask32)
+#define OPT_verbose (option_mask32 & 1)
+#define OPT_silent (option_mask32 & 2)
/*
@@ -351,10 +352,11 @@ static int process_packet(struct dns_entry *conf_data,
uint32_t conf_ttl,
uint8_t *buf)
{
- char *answstr;
struct dns_head *head;
struct type_and_class *unaligned_type_class;
+ const char *err_msg;
char *query_string;
+ char *answstr;
uint8_t *answb;
uint16_t outr_rlen;
uint16_t outr_flags;
@@ -365,12 +367,19 @@ static int process_packet(struct dns_entry *conf_data,
head = (struct dns_head *)buf;
if (head->nquer == 0) {
bb_error_msg("packet has 0 queries, ignored");
- return -1;
+ return 0; /* don't reply */
}
-
if (head->flags & htons(0x8000)) { /* QR bit */
bb_error_msg("response packet, ignored");
- return -1;
+ return 0; /* don't reply */
+ }
+ /* QR = 1 "response", RCODE = 4 "Not Implemented" */
+ outr_flags = htons(0x8000 | 4);
+ err_msg = NULL;
+ /* OPCODE != 0 "standard query" ? */
+ if ((head->flags & htons(0x7800)) != 0) {
+ err_msg = "opcode != 0";
+ goto empty_packet;
}
/* start of query string */
@@ -383,28 +392,16 @@ static int process_packet(struct dns_entry *conf_data,
/* where to append answer block */
answb = (void *)(unaligned_type_class + 1);
- /* QR = 1 "response", RCODE = 4 "Not Implemented" */
- outr_flags = htons(0x8000 | 4);
-
- move_from_unaligned16(type, &unaligned_type_class->type);
- if (type != htons(REQ_A) && type != htons(REQ_PTR)) {
- /* we can't handle this query type */
-//TODO: handle REQ_AAAA (0x1c) requests
- bb_error_msg("type %u is !REQ_A and !REQ_PTR%s",
- (int)ntohs(type),
- ", returning Not Implemented reply");
- goto empty_packet;
- }
move_from_unaligned16(class, &unaligned_type_class->class);
if (class != htons(1)) { /* not class INET? */
- bb_error_msg("class != 1%s",
- ", returning Not Implemented reply");
+ err_msg = "class != 1";
goto empty_packet;
}
- /* OPCODE != 0 "standard query" ? */
- if ((head->flags & htons(0x7800)) != 0) {
- bb_error_msg("opcode != 0%s",
- ", returning Not Implemented reply");
+ move_from_unaligned16(type, &unaligned_type_class->type);
+ if (type != htons(REQ_A) && type != htons(REQ_PTR)) {
+ /* we can't handle this query type */
+//TODO: happens all the time with REQ_AAAA (0x1c) requests - implement those?
+ err_msg = "type is !REQ_A and !REQ_PTR";
goto empty_packet;
}
@@ -425,8 +422,7 @@ static int process_packet(struct dns_entry *conf_data,
/* QR = 1 "response"
* AA = 1 "Authoritative Answer"
* RCODE = 3 "Name Error" */
- if (OPT_verbose)
- bb_error_msg("returning Name Error reply");
+ err_msg = "name is not found";
outr_flags = htons(0x8000 | 0x0400 | 3);
goto empty_packet;
}
@@ -455,6 +451,16 @@ static int process_packet(struct dns_entry *conf_data,
head->nansw = htons(1);
empty_packet:
+ if ((outr_flags & htons(0xf)) != 0) { /* not a positive response */
+ if (OPT_verbose) {
+ bb_error_msg("%s, %s",
+ err_msg,
+ OPT_silent ? "dropping query" : "sending error reply"
+ );
+ }
+ if (OPT_silent)
+ return 0;
+ }
head->flags |= outr_flags;
head->nauth = head->nadd = 0;
head->nquer = htons(1); // why???
@@ -476,21 +482,20 @@ int dnsd_main(int argc UNUSED_PARAM, char **argv)
uint16_t port = 53;
uint8_t buf[MAX_PACK_LEN + 1];
- opts = getopt32(argv, "vi:c:t:p:d", &listen_interface, &fileconf, &sttl, &sport);
- //if (opts & 0x1) // -v
- //if (opts & 0x2) // -i
- //if (opts & 0x4) // -c
- if (opts & 0x8) // -t
+ opts = getopt32(argv, "vsi:c:t:p:d", &listen_interface, &fileconf, &sttl, &sport);
+ //if (opts & (1 << 0)) // -v
+ //if (opts & (1 << 1)) // -s
+ //if (opts & (1 << 2)) // -i
+ //if (opts & (1 << 3)) // -c
+ if (opts & (1 << 4)) // -t
conf_ttl = xatou_range(sttl, 1, 0xffffffff);
- if (opts & 0x10) // -p
+ if (opts & (1 << 5)) // -p
port = xatou_range(sport, 1, 0xffff);
- if (opts & 0x20) { // -d
+ if (opts & (1 << 6)) { // -d
bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
openlog(applet_name, LOG_PID, LOG_DAEMON);
logmode = LOGMODE_SYSLOG;
}
- /* Clear all except "verbose" bit */
- option_mask32 &= 1;
conf_data = parse_conf_file(fileconf);
--
1.6.3.3
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