OpenWrt – Rev 4
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From 5b99eae59d59a8e34a7e512059b98bbd803312f2 Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Sun, 6 Jan 2019 23:09:50 +0000
Subject: [PATCH 24/32] Cache SRV records.
Inpsired by a patch from Jeremy Allison, but completely re-rolled
by srk. All bugs are mine.
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
---
src/auth.c | 2 +-
src/blockdata.c | 12 ++---
src/cache.c | 64 ++++++++++++++--------
src/dnsmasq.c | 2 -
src/dnsmasq.h | 11 ++--
src/rfc1035.c | 141 ++++++++++++++++++++++++++++++++++++++----------
6 files changed, 166 insertions(+), 66 deletions(-)
--- a/src/auth.c
+++ b/src/auth.c
@@ -129,7 +129,7 @@ size_t answer_auth(struct dns_header *he
for (q = ntohs(header->qdcount); q != 0; q--)
{
- unsigned short flag = 0;
+ unsigned int flag = 0;
int found = 0;
int cname_wildcard = 0;
--- a/src/blockdata.c
+++ b/src/blockdata.c
@@ -16,8 +16,6 @@
#include "dnsmasq.h"
-#ifdef HAVE_DNSSEC
-
static struct blockdata *keyblock_free;
static unsigned int blockdata_count, blockdata_hwm, blockdata_alloced;
@@ -54,11 +52,10 @@ void blockdata_init(void)
void blockdata_report(void)
{
- if (option_bool(OPT_DNSSEC_VALID))
- my_syslog(LOG_INFO, _("DNSSEC memory in use %u, max %u, allocated %u"),
- blockdata_count * sizeof(struct blockdata),
- blockdata_hwm * sizeof(struct blockdata),
- blockdata_alloced * sizeof(struct blockdata));
+ my_syslog(LOG_INFO, _("pool memory in use %u, max %u, allocated %u"),
+ blockdata_count * sizeof(struct blockdata),
+ blockdata_hwm * sizeof(struct blockdata),
+ blockdata_alloced * sizeof(struct blockdata));
}
static struct blockdata *blockdata_alloc_real(int fd, char *data, size_t len)
@@ -178,4 +175,3 @@ struct blockdata *blockdata_read(int fd,
return blockdata_alloc_real(fd, NULL, len);
}
-#endif
--- a/src/cache.c
+++ b/src/cache.c
@@ -27,7 +27,7 @@ static int bignames_left, hash_size;
static void make_non_terminals(struct crec *source);
static struct crec *really_insert(char *name, union all_addr *addr, unsigned short class,
- time_t now, unsigned long ttl, unsigned short flags);
+ time_t now, unsigned long ttl, unsigned int flags);
/* type->string mapping: this is also used by the name-hash function as a mixing table. */
static const struct {
@@ -198,15 +198,17 @@ static void cache_hash(struct crec *crec
*up = crecp;
}
-#ifdef HAVE_DNSSEC
static void cache_blockdata_free(struct crec *crecp)
{
- if (crecp->flags & F_DNSKEY)
+ if (crecp->flags & F_SRV)
+ blockdata_free(crecp->addr.srv.target);
+#ifdef HAVE_DNSSEC
+ else if (crecp->flags & F_DNSKEY)
blockdata_free(crecp->addr.key.keydata);
else if ((crecp->flags & F_DS) && !(crecp->flags & F_NEG))
blockdata_free(crecp->addr.ds.keydata);
-}
#endif
+}
static void cache_free(struct crec *crecp)
{
@@ -230,9 +232,7 @@ static void cache_free(struct crec *crec
crecp->flags &= ~F_BIGNAME;
}
-#ifdef HAVE_DNSSEC
cache_blockdata_free(crecp);
-#endif
}
/* insert a new cache entry at the head of the list (youngest entry) */
@@ -331,7 +331,7 @@ static int is_expired(time_t now, struct
}
static struct crec *cache_scan_free(char *name, union all_addr *addr, unsigned short class, time_t now,
- unsigned short flags, struct crec **target_crec, unsigned int *target_uid)
+ unsigned int flags, struct crec **target_crec, unsigned int *target_uid)
{
/* Scan and remove old entries.
If (flags & F_FORWARD) then remove any forward entries for name and any expired
@@ -360,7 +360,7 @@ static struct crec *cache_scan_free(char
if ((crecp->flags & F_FORWARD) && hostname_isequal(cache_get_name(crecp), name))
{
/* Don't delete DNSSEC in favour of a CNAME, they can co-exist */
- if ((flags & crecp->flags & (F_IPV4 | F_IPV6)) ||
+ if ((flags & crecp->flags & (F_IPV4 | F_IPV6 | F_SRV)) ||
(((crecp->flags | flags) & F_CNAME) && !(crecp->flags & (F_DNSKEY | F_DS))))
{
if (crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG))
@@ -467,10 +467,10 @@ void cache_start_insert(void)
}
struct crec *cache_insert(char *name, union all_addr *addr, unsigned short class,
- time_t now, unsigned long ttl, unsigned short flags)
+ time_t now, unsigned long ttl, unsigned int flags)
{
/* Don't log DNSSEC records here, done elsewhere */
- if (flags & (F_IPV4 | F_IPV6 | F_CNAME))
+ if (flags & (F_IPV4 | F_IPV6 | F_CNAME | F_SRV))
{
log_query(flags | F_UPSTREAM, name, addr, NULL);
/* Don't mess with TTL for DNSSEC records. */
@@ -485,7 +485,7 @@ struct crec *cache_insert(char *name, un
static struct crec *really_insert(char *name, union all_addr *addr, unsigned short class,
- time_t now, unsigned long ttl, unsigned short flags)
+ time_t now, unsigned long ttl, unsigned int flags)
{
struct crec *new, *target_crec = NULL;
union bigname *big_name = NULL;
@@ -649,7 +649,7 @@ void cache_end_insert(void)
{
char *name = cache_get_name(new_chain);
ssize_t m = strlen(name);
- unsigned short flags = new_chain->flags;
+ unsigned int flags = new_chain->flags;
#ifdef HAVE_DNSSEC
u16 class = new_chain->uid;
#endif
@@ -659,8 +659,10 @@ void cache_end_insert(void)
read_write(daemon->pipe_to_parent, (unsigned char *)&new_chain->ttd, sizeof(new_chain->ttd), 0);
read_write(daemon->pipe_to_parent, (unsigned char *)&flags, sizeof(flags), 0);
- if (flags & (F_IPV4 | F_IPV6 | F_DNSKEY | F_DS))
+ if (flags & (F_IPV4 | F_IPV6 | F_DNSKEY | F_DS | F_SRV))
read_write(daemon->pipe_to_parent, (unsigned char *)&new_chain->addr, sizeof(new_chain->addr), 0);
+ if (flags & F_SRV)
+ blockdata_write(new_chain->addr.srv.target, new_chain->addr.srv.targetlen, daemon->pipe_to_parent);
#ifdef HAVE_DNSSEC
if (flags & F_DNSKEY)
{
@@ -699,7 +701,7 @@ int cache_recv_insert(time_t now, int fd
union all_addr addr;
unsigned long ttl;
time_t ttd;
- unsigned short flags;
+ unsigned int flags;
struct crec *crecp = NULL;
cache_start_insert();
@@ -725,13 +727,16 @@ int cache_recv_insert(time_t now, int fd
ttl = difftime(ttd, now);
- if (flags & (F_IPV4 | F_IPV6 | F_DNSKEY | F_DS))
+ if (flags & (F_IPV4 | F_IPV6 | F_DNSKEY | F_DS | F_SRV))
{
unsigned short class = C_IN;
if (!read_write(fd, (unsigned char *)&addr, sizeof(addr), 1))
return 0;
-
+
+ if (flags & F_SRV && !(addr.srv.target = blockdata_read(fd, addr.srv.targetlen)))
+ return 0;
+
#ifdef HAVE_DNSSEC
if (flags & F_DNSKEY)
{
@@ -802,7 +807,7 @@ struct crec *cache_find_by_name(struct c
/* first search, look for relevant entries and push to top of list
also free anything which has expired */
struct crec *next, **up, **insert = NULL, **chainp = &ans;
- unsigned short ins_flags = 0;
+ unsigned int ins_flags = 0;
for (up = hash_bucket(name), crecp = *up; crecp; crecp = next)
{
@@ -1086,7 +1091,7 @@ int read_hostsfile(char *filename, unsig
FILE *f = fopen(filename, "r");
char *token = daemon->namebuff, *domain_suffix = NULL;
int addr_count = 0, name_count = cache_size, lineno = 0;
- unsigned short flags = 0;
+ unsigned int flags = 0;
union all_addr addr;
int atnl, addrlen = 0;
@@ -1201,9 +1206,8 @@ void cache_reload(void)
for (i=0; i<hash_size; i++)
for (cache = hash_table[i], up = &hash_table[i]; cache; cache = tmp)
{
-#ifdef HAVE_DNSSEC
cache_blockdata_free(cache);
-#endif
+
tmp = cache->hash_next;
if (cache->flags & (F_HOSTS | F_CONFIG))
{
@@ -1381,7 +1385,7 @@ void cache_add_dhcp_entry(char *host_nam
union all_addr *host_address, time_t ttd)
{
struct crec *crec = NULL, *fail_crec = NULL;
- unsigned short flags = F_IPV4;
+ unsigned int flags = F_IPV4;
int in_hosts = 0;
size_t addrlen = sizeof(struct in_addr);
@@ -1682,9 +1686,8 @@ void dump_cache(time_t now)
#ifdef HAVE_AUTH
my_syslog(LOG_INFO, _("queries for authoritative zones %u"), daemon->metrics[METRIC_DNS_AUTH_ANSWERED]);
#endif
-#ifdef HAVE_DNSSEC
+
blockdata_report();
-#endif
/* sum counts from different records for same server */
for (serv = daemon->servers; serv; serv = serv->next)
@@ -1726,6 +1729,17 @@ void dump_cache(time_t now)
p += sprintf(p, "%-30.30s ", sanitise(n));
if ((cache->flags & F_CNAME) && !is_outdated_cname_pointer(cache))
a = sanitise(cache_get_cname_target(cache));
+ else if ((cache->flags & F_SRV) && !(cache->flags & F_NEG))
+ {
+ int targetlen = cache->addr.srv.targetlen;
+ ssize_t len = sprintf(a, "%u %u %u ", cache->addr.srv.priority,
+ cache->addr.srv.weight, cache->addr.srv.srvport);
+
+ if (targetlen > (40 - len))
+ targetlen = 40 - len;
+ blockdata_retrieve(cache->addr.srv.target, targetlen, a + len);
+ a[len + targetlen] = 0;
+ }
#ifdef HAVE_DNSSEC
else if (cache->flags & F_DS)
{
@@ -1752,6 +1766,8 @@ void dump_cache(time_t now)
t = "6";
else if (cache->flags & F_CNAME)
t = "C";
+ else if (cache->flags & F_SRV)
+ t = "V";
#ifdef HAVE_DNSSEC
else if (cache->flags & F_DS)
t = "S";
@@ -1913,6 +1929,8 @@ void log_query(unsigned int flags, char
}
else if (flags & F_CNAME)
dest = "<CNAME>";
+ else if (flags & F_SRV)
+ dest = "<SRV>";
else if (flags & F_RRNAME)
dest = arg;
--- a/src/dnsmasq.c
+++ b/src/dnsmasq.c
@@ -366,9 +366,7 @@ int main (int argc, char **argv)
{
cache_init();
-#ifdef HAVE_DNSSEC
blockdata_init();
-#endif
}
#ifdef HAVE_INOTIFY
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -299,6 +299,10 @@ union all_addr {
unsigned char algo;
unsigned char digest;
} ds;
+ struct {
+ struct blockdata *target;
+ unsigned short targetlen, srvport, priority, weight;
+ } srv;
/* for log_query */
struct {
unsigned short keytag, algo, digest, rcode;
@@ -426,7 +430,7 @@ struct crec {
time_t ttd; /* time to die */
/* used as class if DNSKEY/DS, index to source for F_HOSTS */
unsigned int uid;
- unsigned short flags;
+ unsigned int flags;
union {
char sname[SMALLDNAME];
union bigname *bname;
@@ -470,6 +474,7 @@ struct crec {
#define F_NOEXTRA (1u<<27)
#define F_SERVFAIL (1u<<28)
#define F_RCODE (1u<<29)
+#define F_SRV (1u<<30)
#define UID_NONE 0
/* Values of uid in crecs with F_CONFIG bit set. */
@@ -1142,7 +1147,7 @@ void cache_end_insert(void);
void cache_start_insert(void);
int cache_recv_insert(time_t now, int fd);
struct crec *cache_insert(char *name, union all_addr *addr, unsigned short class,
- time_t now, unsigned long ttl, unsigned short flags);
+ time_t now, unsigned long ttl, unsigned int flags);
void cache_reload(void);
void cache_add_dhcp_entry(char *host_name, int prot, union all_addr *host_address, time_t ttd);
struct in_addr a_record_from_hosts(char *name, time_t now);
@@ -1158,7 +1163,6 @@ int read_hostsfile(char *filename, unsig
struct crec **rhash, int hashsz);
/* blockdata.c */
-#ifdef HAVE_DNSSEC
void blockdata_init(void);
void blockdata_report(void);
struct blockdata *blockdata_alloc(char *data, size_t len);
@@ -1166,7 +1170,6 @@ void *blockdata_retrieve(struct blockdat
struct blockdata *blockdata_read(int fd, size_t len);
void blockdata_write(struct blockdata *block, size_t len, int fd);
void blockdata_free(struct blockdata *blocks);
-#endif
/* domain.c */
char *get_domain(struct in_addr addr);
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -726,7 +726,7 @@ int extract_addresses(struct dns_header
{
/* everything other than PTR */
struct crec *newc;
- int addrlen;
+ int addrlen = 0;
if (qtype == T_A)
{
@@ -738,7 +738,9 @@ int extract_addresses(struct dns_header
addrlen = IN6ADDRSZ;
flags |= F_IPV6;
}
- else
+ else if (qtype == T_SRV)
+ flags |= F_SRV;
+ else
continue;
cname_loop1:
@@ -799,39 +801,61 @@ int extract_addresses(struct dns_header
{
found = 1;
- /* copy address into aligned storage */
- if (!CHECK_LEN(header, p1, qlen, addrlen))
- return 0; /* bad packet */
- memcpy(&addr, p1, addrlen);
-
- /* check for returned address in private space */
- if (check_rebind)
+ if (flags & F_SRV)
{
- if ((flags & F_IPV4) &&
- private_net(addr.addr4, !option_bool(OPT_LOCAL_REBIND)))
- return 1;
-
- if ((flags & F_IPV6) &&
- IN6_IS_ADDR_V4MAPPED(&addr.addr6))
+ unsigned char *tmp = namep;
+
+ if (!CHECK_LEN(header, p1, qlen, 6))
+ return 0; /* bad packet */
+ GETSHORT(addr.srv.priority, p1);
+ GETSHORT(addr.srv.weight, p1);
+ GETSHORT(addr.srv.srvport, p1);
+ if (!extract_name(header, qlen, &p1, name, 1, 0))
+ return 0;
+ addr.srv.targetlen = strlen(name) + 1; /* include terminating zero */
+ if (!(addr.srv.target = blockdata_alloc(name, addr.srv.targetlen)))
+ return 0;
+
+ /* we overwrote the original name, so get it back here. */
+ if (!extract_name(header, qlen, &tmp, name, 1, 0))
+ return 0;
+ }
+ else
+ {
+ /* copy address into aligned storage */
+ if (!CHECK_LEN(header, p1, qlen, addrlen))
+ return 0; /* bad packet */
+ memcpy(&addr, p1, addrlen);
+
+ /* check for returned address in private space */
+ if (check_rebind)
{
- struct in_addr v4;
- v4.s_addr = ((const uint32_t *) (&addr.addr6))[3];
- if (private_net(v4, !option_bool(OPT_LOCAL_REBIND)))
+ if ((flags & F_IPV4) &&
+ private_net(addr.addr4, !option_bool(OPT_LOCAL_REBIND)))
return 1;
+
+ if ((flags & F_IPV6) &&
+ IN6_IS_ADDR_V4MAPPED(&addr.addr6))
+ {
+ struct in_addr v4;
+ v4.s_addr = ((const uint32_t *) (&addr.addr6))[3];
+ if (private_net(v4, !option_bool(OPT_LOCAL_REBIND)))
+ return 1;
+ }
}
- }
-
+
#ifdef HAVE_IPSET
- if (ipsets && (flags & (F_IPV4 | F_IPV6)))
- {
- ipsets_cur = ipsets;
- while (*ipsets_cur)
+ if (ipsets && (flags & (F_IPV4 | F_IPV6)))
{
- log_query((flags & (F_IPV4 | F_IPV6)) | F_IPSET, name, &addr, *ipsets_cur);
- add_to_ipset(*ipsets_cur++, &addr, flags, 0);
+ ipsets_cur = ipsets;
+ while (*ipsets_cur)
+ {
+ log_query((flags & (F_IPV4 | F_IPV6)) | F_IPSET, name, &addr, *ipsets_cur);
+ add_to_ipset(*ipsets_cur++, &addr, flags, 0);
+ }
}
- }
#endif
+ }
newc = cache_insert(name, &addr, C_IN, now, attl, flags | F_FORWARD | secflag);
if (newc && cpp)
@@ -1844,7 +1868,68 @@ size_t answer_request(struct dns_header
*up = move;
move->next = NULL;
}
-
+
+ if (!found)
+ {
+ cname_srv_restart:
+ if ((crecp = cache_find_by_name(NULL, name, now, F_CNAME | F_SRV | (dryrun ? F_NO_RR : 0))) &&
+ (!do_bit || (option_bool(OPT_DNSSEC_VALID) && !(crecp->flags & F_DNSSECOK))))
+ {
+ if (!(crecp->flags & F_DNSSECOK))
+ sec_data = 0;
+
+ auth = 0;
+ found = ans = 1;
+
+ do {
+ if (crecp->flags & F_CNAME)
+ {
+ char *cname_target = cache_get_cname_target(crecp);
+
+ if (!dryrun)
+ {
+ log_query(crecp->flags, name, NULL, record_source(crecp->uid));
+ if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
+ crec_ttl(crecp, now), &nameoffset,
+ T_CNAME, C_IN, "d", cname_target))
+ anscount++;
+ }
+
+ strcpy(name, cname_target);
+ goto cname_srv_restart;
+ }
+ else if (crecp->flags & F_NEG)
+ {
+ if (crecp->flags & F_NXDOMAIN)
+ nxdomain = 1;
+ if (!dryrun)
+ log_query(crecp->flags, name, NULL, NULL);
+ }
+ else
+ {
+ unsigned char *p1 = ((unsigned char *)header) + nameoffset;
+
+ if (!dryrun)
+ {
+ log_query(crecp->flags, name, NULL, 0);
+
+ blockdata_retrieve(crecp->addr.srv.target, crecp->addr.srv.targetlen, name);
+ if (add_resource_record(header, limit, &trunc, nameoffset, &ansp,
+ crec_ttl(crecp, now), NULL, T_SRV, C_IN, "sssd",
+ crecp->addr.srv.priority, crecp->addr.srv.weight, crecp->addr.srv.srvport,
+ name))
+ anscount++;
+
+
+ /* restore name we overwrote */
+ if (!extract_name(header, qlen, &p1, name, 1, 0))
+ return 0; /* bad packet */
+ }
+ }
+ } while ((crecp = cache_find_by_name(crecp, name, now, F_SRV | F_CNAME)));
+ }
+ }
+
if (!found && option_bool(OPT_FILTER) && (qtype == T_SRV || (qtype == T_ANY && strchr(name, '_'))))
{
ans = 1;