https://thekelleys.org.uk/dnsmasq/
dnsmasq自带min-cache-ttl可修改服务器缓存最小值，但是首次请求返回给客户端ttl的是正常ttl，使用以下patch可修改返回给客户端ttl时间，配合min-cache-ttl保持和dnsmasq缓存ttl时间一致，dnsmasq不开启缓存可单独修改min_ttl
dnsmasq-2.86版本
--- a/src/config.h
+++ b/src/config.h
@@ -31,7 +31,7 @@
#define LOCALS_LOGGED 8 /* Only log this many local addresses when logging state */
#define LEASE_RETRY 60 /* on error, retry writing leasefile after LEASE_RETRY seconds */
#define CACHESIZ 150 /* default cache size */
-#define TTL_FLOOR_LIMIT 3600 /* don't allow --min-cache-ttl to raise TTL above this under any circumstances */
+#define TTL_FLOOR_LIMIT 86400 /* don't allow --min-cache-ttl to raise TTL above this under any circumstances */
#define MAXLEASES 1000 /* maximum number of DHCP leases */
#define PING_WAIT 3 /* wait for ping address-in-use test */
#define PING_CACHE_TIME 30 /* Ping test assumed to be valid this long. */
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -1116,7 +1116,7 @@ extern struct daemon {
int max_logs; /* queue limit */
int cachesize, ftabsize;
int port, query_port, min_port, max_port;
- unsigned long local_ttl, neg_ttl, max_ttl, min_cache_ttl, max_cache_ttl, auth_ttl, dhcp_ttl, use_dhcp_ttl;
+ unsigned long local_ttl, neg_ttl, min_ttl, max_ttl, min_cache_ttl, max_cache_ttl, auth_ttl, dhcp_ttl, use_dhcp_ttl;
char *dns_client_id;
u32 umbrella_org;
u32 umbrella_asset;
--- a/src/option.c
+++ b/src/option.c
@@ -174,6 +174,7 @@ struct myoption {
#define LOPT_CMARK_ALST_EN 365
#define LOPT_CMARK_ALST 366
#define LOPT_QUIET_TFTP 367
+#define LOPT_MINTTL 368
#ifdef HAVE_GETOPT_LONG
static const struct option opts[] =
@@ -292,6 +293,7 @@ static const struct myoption opts[] =
{ "dhcp-name-match", 1, 0, LOPT_NAME_MATCH },
{ "dhcp-broadcast", 2, 0, LOPT_BROADCAST },
{ "neg-ttl", 1, 0, LOPT_NEGTTL },
+ { "min-ttl", 1, 0, LOPT_MINTTL },
{ "max-ttl", 1, 0, LOPT_MAXTTL },
{ "min-cache-ttl", 1, 0, LOPT_MINCTTL },
{ "max-cache-ttl", 1, 0, LOPT_MAXCTTL },
@@ -425,6 +427,7 @@ static struct {
{ 't', ARG_ONE, "<host_name>", gettext_noop("Specify default target in an MX record."), NULL },
{ 'T', ARG_ONE, "<integer>", gettext_noop("Specify time-to-live in seconds for replies from /etc/hosts."), NULL },
{ LOPT_NEGTTL, ARG_ONE, "<integer>", gettext_noop("Specify time-to-live in seconds for negative caching."), NULL },
+ { LOPT_MINTTL, ARG_ONE, "<integer>", gettext_noop("Specify time-to-live in seconds for minimum TTL to send to clients."), NULL },
{ LOPT_MAXTTL, ARG_ONE, "<integer>", gettext_noop("Specify time-to-live in seconds for maximum TTL to send to clients."), NULL },
{ LOPT_MAXCTTL, ARG_ONE, "<integer>", gettext_noop("Specify time-to-live ceiling for cache."), NULL },
{ LOPT_MINCTTL, ARG_ONE, "<integer>", gettext_noop("Specify time-to-live floor for cache."), NULL },
@@ -3047,6 +3050,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
case 'T': /* --local-ttl */
case LOPT_NEGTTL: /* --neg-ttl */
+ case LOPT_MINTTL: /* --min-ttl */
case LOPT_MAXTTL: /* --max-ttl */
case LOPT_MINCTTL: /* --min-cache-ttl */
case LOPT_MAXCTTL: /* --max-cache-ttl */
@@ -3058,6 +3062,8 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
ret_err(gen_err);
else if (option == LOPT_NEGTTL)
daemon->neg_ttl = (unsigned long)ttl;
+ else if (option == LOPT_MINTTL)
+ daemon->min_ttl = (unsigned long)ttl;
else if (option == LOPT_MAXTTL)
daemon->max_ttl = (unsigned long)ttl;
else if (option == LOPT_MINCTTL)
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -607,6 +607,7 @@
for (j = 0; j < ntohs(header->ancount); j++)
{
int secflag = 0;
+ unsigned long mttl = 0;
if (!(res = extract_name(header, qlen, &p1, name, 0, 10)))
return 0; /* bad packet */
@@ -615,9 +616,17 @@
GETLONG(attl, p1);
if ((daemon->max_ttl != 0) && (attl > daemon->max_ttl) && !is_sign)
+ {
+ mttl = daemon->max_ttl;
+ }
+ if ((daemon->min_ttl != 0) && (attl < daemon->min_ttl) && !is_sign)
+ {
+ mttl = daemon->min_ttl;
+ }
+ if (mttl != 0)
{
(p1) -= 4;
- PUTLONG(daemon->max_ttl, p1);
+ PUTLONG(mttl, p1);
}
GETSHORT(ardlen, p1);
endrr = p1+ardlen;
@@ -722,6 +731,7 @@
for (j = 0; j < ntohs(header->ancount); j++)
{
int secflag = 0;
+ unsigned long mttl = 0;
if (!(res = extract_name(header, qlen, &p1, name, 0, 10)))
return 0; /* bad packet */
@@ -730,9 +740,17 @@
GETSHORT(aqclass, p1);
GETLONG(attl, p1);
if ((daemon->max_ttl != 0) && (attl > daemon->max_ttl) && !is_sign)
+ {
+ mttl = daemon->max_ttl;
+ }
+ if ((daemon->min_ttl != 0) && (attl < daemon->min_ttl) && !is_sign)
+ {
+ mttl = daemon->min_ttl;
+ }
+ if (mttl != 0)
{
(p1) -= 4;
- PUTLONG(daemon->max_ttl, p1);
+ PUTLONG(mttl, p1);
}
GETSHORT(ardlen, p1);
endrr = p1+ardlen;
patch补丁的生成
diff -urN a/src/config.h b/src/config.h >> diff.patchmin-ttl=86400 #第一次返回给客户端的ttl
min-cache-ttl=86400 #dnsmasq服务端缓存时间设定