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authd: import stripped down charybdis resolver

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This commit is contained in:
William Pitcock 2016-01-06 02:47:22 -06:00
parent 0d73e7db9c
commit ed62c46ba1
6 changed files with 2319 additions and 3 deletions
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2
authd/Makefile.am
View file

@ -3,5 +3,5 @@ AM_CFLAGS=$(WARNFLAGS)
AM_CPPFLAGS = -I../include -I../libratbox/include
authd_SOURCES = authd.c
authd_SOURCES = authd.c res.c reslib.c
authd_LDADD = ../libratbox/src/libratbox.la

6
authd/Makefile.in
View file

@ -107,7 +107,7 @@ CONFIG_CLEAN_FILES =
CONFIG_CLEAN_VPATH_FILES =
am__installdirs = "$(DESTDIR)$(pkglibexecdir)"
PROGRAMS = $(pkglibexec_PROGRAMS)
am_authd_OBJECTS = authd.$(OBJEXT)
am_authd_OBJECTS = authd.$(OBJEXT) res.$(OBJEXT) reslib.$(OBJEXT)
authd_OBJECTS = $(am_authd_OBJECTS)
authd_DEPENDENCIES = ../libratbox/src/libratbox.la
AM_V_lt = $(am__v_lt_@AM_V@)
@ -358,7 +358,7 @@ top_builddir = @top_builddir@
top_srcdir = @top_srcdir@
AM_CFLAGS = $(WARNFLAGS)
AM_CPPFLAGS = -I../include -I../libratbox/include
authd_SOURCES = authd.c
authd_SOURCES = authd.c res.c reslib.c
authd_LDADD = ../libratbox/src/libratbox.la
all: all-am
@ -454,6 +454,8 @@ distclean-compile:
-rm -f *.tab.c
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/authd.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/res.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/reslib.Po@am__quote@
.c.o:
@am__fastdepCC_TRUE@ $(AM_V_CC)$(COMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<

972
authd/res.c Normal file
View file

@ -0,0 +1,972 @@
/*
* A rewrite of Darren Reeds original res.c As there is nothing
* left of Darrens original code, this is now licensed by the hybrid group.
* (Well, some of the function names are the same, and bits of the structs..)
* You can use it where it is useful, free even. Buy us a beer and stuff.
*
* The authors takes no responsibility for any damage or loss
* of property which results from the use of this software.
*
* $Id: res.c 3301 2007-03-28 15:04:06Z jilles $
* from Hybrid Id: res.c 459 2006-02-12 22:21:37Z db $
*
* July 1999 - Rewrote a bunch of stuff here. Change hostent builder code,
* added callbacks and reference counting of returned hostents.
* --Bleep (Thomas Helvey <tomh@inxpress.net>)
*
* This was all needlessly complicated for irc. Simplified. No more hostent
* All we really care about is the IP -> hostname mappings. Thats all.
*
* Apr 28, 2003 --cryogen and Dianora
*
* DNS server flooding lessened, AAAA-or-A lookup removed, ip6.int support
* removed, various robustness fixes
*
* 2006 --jilles and nenolod
*
* Resend queries to other servers if the DNS server replies with an error or
* an invalid response. Also, avoid servers that return errors or invalid
* responses.
*
* October 2012 --mr_flea
*
* ircd-ratbox changes for random IDs merged back in.
*
* January 2016 --kaniini
*/
#include <ratbox_lib.h>
#include "setup.h"
#include "res.h"
#include "reslib.h"
#if (CHAR_BIT != 8)
#error this code needs to be able to address individual octets
#endif
static PF res_readreply;
#define MAXPACKET 1024 /* rfc sez 512 but we expand names so ... */
#define RES_MAXALIASES 35 /* maximum aliases allowed */
#define RES_MAXADDRS 35 /* maximum addresses allowed */
#define AR_TTL 600 /* TTL in seconds for dns cache entries */
/* RFC 1104/1105 wasn't very helpful about what these fields
* should be named, so for now, we'll just name them this way.
* we probably should look at what named calls them or something.
*/
#define TYPE_SIZE (size_t)2
#define CLASS_SIZE (size_t)2
#define TTL_SIZE (size_t)4
#define RDLENGTH_SIZE (size_t)2
#define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE)
#ifdef RB_IPV6
extern struct in6_addr ipv6_addr;
#endif
extern struct in_addr ipv4_addr;
struct reslist
{
rb_dlink_node node;
int id;
time_t ttl;
char type;
char queryname[IRCD_RES_HOSTLEN + 1]; /* name currently being queried */
char retries; /* retry counter */
char sends; /* number of sends (>1 means resent) */
time_t sentat;
time_t timeout;
int lastns; /* index of last server sent to */
struct rb_sockaddr_storage addr;
char *name;
struct DNSQuery *query; /* query callback for this request */
};
static rb_fde_t *res_fd;
static rb_dlink_list request_list = { NULL, NULL, 0 };
static int ns_failure_count[IRCD_MAXNS]; /* timeouts and invalid/failed replies */
static void rem_request(struct reslist *request);
static struct reslist *make_request(struct DNSQuery *query);
static void gethost_byname_type_fqdn(const char *name, struct DNSQuery *query,
int type);
static void do_query_name(struct DNSQuery *query, const char *name, struct reslist *request, int);
static void do_query_number(struct DNSQuery *query, const struct rb_sockaddr_storage *,
struct reslist *request);
static void query_name(struct reslist *request);
static int send_res_msg(const char *buf, int len, int count);
static void resend_query(struct reslist *request);
static int check_question(struct reslist *request, HEADER * header, char *buf, char *eob);
static int proc_answer(struct reslist *request, HEADER * header, char *, char *);
static struct reslist *find_id(int id);
static struct DNSReply *make_dnsreply(struct reslist *request);
static int generate_random_port(void);
static uint16_t generate_random_id(void);
#ifdef RES_MIN
#undef RES_MIN
#endif
#define RES_MIN(a, b) ((a) < (b) ? (a) : (b))
static rb_fde_t *
random_socket(int family)
{
rb_fde_t *F;
int nport;
int i;
rb_socklen_t len;
struct rb_sockaddr_storage sockaddr;
F = rb_socket(family, SOCK_DGRAM, 0, "UDP resolver socket");
if(F == NULL)
return NULL;
memset(&sockaddr, 0, sizeof(sockaddr));
SET_SS_FAMILY(&sockaddr, family);
#ifdef RB_IPV6
if(family == AF_INET6)
{
struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&sockaddr;
memcpy(&in6->sin6_addr, &ipv6_addr, sizeof(struct in6_addr));
len = (rb_socklen_t) sizeof(struct sockaddr_in6);
}
else
#endif
{
struct sockaddr_in *in = (struct sockaddr_in *)&sockaddr;
in->sin_addr.s_addr = ipv4_addr.s_addr;
len = (rb_socklen_t) sizeof(struct sockaddr_in);
}
for(i = 0; i < 10; i++)
{
nport = htons(generate_random_port());
if(family == AF_INET)
((struct sockaddr_in *)&sockaddr)->sin_port = nport;
#ifdef RB_IPV6
else
((struct sockaddr_in6 *)&sockaddr)->sin6_port = nport;
#endif
if(bind(rb_get_fd(F), (struct sockaddr *)&sockaddr, len) == 0)
return F;
}
rb_close(F);
return NULL;
}
/*
* int
* res_ourserver(inp)
* looks up "inp" in irc_nsaddr_list[]
* returns:
* server ID or -1 for not found
* author:
* paul vixie, 29may94
* revised for ircd, cryogen(stu) may03
* slightly modified for charybdis, mr_flea oct12
*/
static int res_ourserver(const struct rb_sockaddr_storage *inp)
{
#ifdef RB_IPV6
const struct sockaddr_in6 *v6;
const struct sockaddr_in6 *v6in = (const struct sockaddr_in6 *)inp;
#endif
const struct sockaddr_in *v4;
const struct sockaddr_in *v4in = (const struct sockaddr_in *)inp;
int ns;
for (ns = 0; ns < irc_nscount; ns++)
{
const struct rb_sockaddr_storage *srv = &irc_nsaddr_list[ns];
if (srv->ss_family != inp->ss_family)
continue;
#ifdef RB_IPV6
v6 = (const struct sockaddr_in6 *)srv;
#endif
v4 = (const struct sockaddr_in *)srv;
/* could probably just memcmp(srv, inp, srv.ss_len) here
* but we'll err on the side of caution - stu
*/
switch (srv->ss_family)
{
#ifdef RB_IPV6
case AF_INET6:
if (v6->sin6_port == v6in->sin6_port)
if ((memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr,
sizeof(struct in6_addr)) == 0) ||
(memcmp(&v6->sin6_addr.s6_addr, &in6addr_any,
sizeof(struct in6_addr)) == 0))
{
return ns;
}
break;
#endif
case AF_INET:
if (v4->sin_port == v4in->sin_port)
if ((v4->sin_addr.s_addr == INADDR_ANY)
|| (v4->sin_addr.s_addr == v4in->sin_addr.s_addr))
{
return ns;
}
break;
default:
break;
}
}
return -1;
}
/*
* timeout_query_list - Remove queries from the list which have been
* there too long without being resolved.
*/
static time_t timeout_query_list(time_t now)
{
rb_dlink_node *ptr;
rb_dlink_node *next_ptr;
struct reslist *request;
time_t next_time = 0;
time_t timeout = 0;
RB_DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head)
{
request = ptr->data;
timeout = request->sentat + request->timeout;
if (now >= timeout)
{
ns_failure_count[request->lastns]++;
request->sentat = now;
request->timeout += request->timeout;
resend_query(request);
}
if ((next_time == 0) || timeout < next_time)
{
next_time = timeout;
}
}
return (next_time > now) ? next_time : (now + AR_TTL);
}
/*
* timeout_resolver - check request list
*/
static void timeout_resolver(void *notused)
{
timeout_query_list(rb_current_time());
}
static struct ev_entry *timeout_resolver_ev = NULL;
/*
* start_resolver - do everything we need to read the resolv.conf file
* and initialize the resolver file descriptor if needed
*/
static void start_resolver(void)
{
int i;
irc_res_init();
for (i = 0; i < irc_nscount; i++)
ns_failure_count[i] = 0;
if (res_fd == NULL)
{
if ((res_fd = rb_socket(irc_nsaddr_list[0].ss_family, SOCK_DGRAM, 0,
"UDP resolver socket")) == NULL)
return;
/* At the moment, the resolver FD data is global .. */
rb_setselect(res_fd, RB_SELECT_READ, res_readreply, NULL);
timeout_resolver_ev = rb_event_add("timeout_resolver", timeout_resolver, NULL, 1);
}
}
/*
* init_resolver - initialize resolver and resolver library
*/
void init_resolver(void)
{
#ifdef HAVE_SRAND48
srand48(rb_current_time());
#endif
start_resolver();
}
/*
* restart_resolver - reread resolv.conf, reopen socket
*/
void restart_resolver(void)
{
rb_close(res_fd);
res_fd = NULL;
rb_event_delete(timeout_resolver_ev); /* -ddosen */
start_resolver();
}
/*
* add_local_domain - Add the domain to hostname, if it is missing
* (as suggested by eps@TOASTER.SFSU.EDU)
*/
void add_local_domain(char *hname, size_t size)
{
/* try to fix up unqualified names */
if (strchr(hname, '.') == NULL)
{
if (irc_domain[0])
{
size_t len = strlen(hname);
if ((strlen(irc_domain) + len + 2) < size)
{
hname[len++] = '.';
strcpy(hname + len, irc_domain);
}
}
}
}
/*
* rem_request - remove a request from the list.
* This must also free any memory that has been allocated for
* temporary storage of DNS results.
*/
static void rem_request(struct reslist *request)
{
rb_dlinkDelete(&request->node, &request_list);
rb_free(request->name);
rb_free(request);
}
/*
* make_request - Create a DNS request record for the server.
*/
static struct reslist *make_request(struct DNSQuery *query)
{
struct reslist *request = rb_malloc(sizeof(struct reslist));
request->sentat = rb_current_time();
request->retries = 3;
request->timeout = 4; /* start at 4 and exponential inc. */
request->query = query;
/*
* generate a unique id
* NOTE: we don't have to worry about converting this to and from
* network byte order, the nameserver does not interpret this value
* and returns it unchanged
*
* we generate an id per request now (instead of per send) to allow
* late replies to be used.
*/
request->id = generate_random_id();
rb_dlinkAdd(request, &request->node, &request_list);
return request;
}
/*
* retryfreq - determine how many queries to wait before resending
* if there have been that many consecutive timeouts
*/
static int retryfreq(int timeouts)
{
switch (timeouts)
{
case 1:
return 3;
case 2:
return 9;
case 3:
return 27;
case 4:
return 81;
default:
return 243;
}
}
/*
* send_res_msg - sends msg to a nameserver.
* This should reflect /etc/resolv.conf.
* Returns number of nameserver successfully sent to
* or -1 if no successful sends.
*/
static int send_res_msg(const char *msg, int len, int rcount)
{
int i;
int ns;
static int retrycnt;
retrycnt++;
/* First try a nameserver that seems to work.
* Every once in a while, try a possibly broken one to check
* if it is working again.
*/
for (i = 0; i < irc_nscount; i++)
{
ns = (i + rcount - 1) % irc_nscount;
if (ns_failure_count[ns] && retrycnt % retryfreq(ns_failure_count[ns]))
continue;
if (sendto(rb_get_fd(res_fd), msg, len, 0,
(struct sockaddr *)&(irc_nsaddr_list[ns]),
GET_SS_LEN(&irc_nsaddr_list[ns])) == len)
return ns;
}
/* No known working nameservers, try some broken one. */
for (i = 0; i < irc_nscount; i++)
{
ns = (i + rcount - 1) % irc_nscount;
if (!ns_failure_count[ns])
continue;
if (sendto(rb_get_fd(res_fd), msg, len, 0,
(struct sockaddr *)&(irc_nsaddr_list[ns]),
GET_SS_LEN(&irc_nsaddr_list[ns])) == len)
return ns;
}
return -1;
}
/*
* find_id - find a dns request id (id is determined by dn_mkquery)
*/
static struct reslist *find_id(int id)
{
rb_dlink_node *ptr;
struct reslist *request;
RB_DLINK_FOREACH(ptr, request_list.head)
{
request = ptr->data;
if (request->id == id)
return (request);
}
return (NULL);
}
static uint16_t
generate_random_id(void)
{
uint16_t id;
do
{
rb_get_random(&id, sizeof(id));
if(id == 0xffff)
continue;
}
while(find_id(id));
return id;
}
static int
generate_random_port(void)
{
uint16_t port;
while(1)
{
rb_get_random(&port, sizeof(port));
if(port > 1024)
break;
}
return (int)port;
}
/*
* gethost_byname_type - get host address from name, adding domain if needed
*/
void gethost_byname_type(const char *name, struct DNSQuery *query, int type)
{
char fqdn[IRCD_RES_HOSTLEN + 1];
assert(name != 0);
rb_strlcpy(fqdn, name, sizeof fqdn);
add_local_domain(fqdn, IRCD_RES_HOSTLEN);
gethost_byname_type_fqdn(fqdn, query, type);
}
/*
* gethost_byname_type_fqdn - get host address from fqdn
*/
static void gethost_byname_type_fqdn(const char *name, struct DNSQuery *query,
int type)
{
assert(name != 0);
do_query_name(query, name, NULL, type);
}
/*
* gethost_byaddr - get host name from address
*/
void gethost_byaddr(const struct rb_sockaddr_storage *addr, struct DNSQuery *query)
{
do_query_number(query, addr, NULL);
}
/*
* do_query_name - nameserver lookup name
*/
static void do_query_name(struct DNSQuery *query, const char *name, struct reslist *request,
int type)
{
if (request == NULL)
{
request = make_request(query);
request->name = rb_strdup(name);
}
rb_strlcpy(request->queryname, name, sizeof(request->queryname));
request->type = type;
query_name(request);
}
/*
* do_query_number - Use this to do reverse IP# lookups.
*/
static void do_query_number(struct DNSQuery *query, const struct rb_sockaddr_storage *addr,
struct reslist *request)
{
const unsigned char *cp;
if (request == NULL)
{
request = make_request(query);
memcpy(&request->addr, addr, sizeof(struct rb_sockaddr_storage));
request->name = (char *)rb_malloc(IRCD_RES_HOSTLEN + 1);
}
if (addr->ss_family == AF_INET)
{
const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr;
cp = (const unsigned char *)&v4->sin_addr.s_addr;
rb_sprintf(request->queryname, "%u.%u.%u.%u.in-addr.arpa", (unsigned int)(cp[3]),
(unsigned int)(cp[2]), (unsigned int)(cp[1]), (unsigned int)(cp[0]));
}
#ifdef RB_IPV6
else if (addr->ss_family == AF_INET6)
{
const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr;
cp = (const unsigned char *)&v6->sin6_addr.s6_addr;
(void)sprintf(request->queryname, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x."
"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa",
(unsigned int)(cp[15] & 0xf), (unsigned int)(cp[15] >> 4),
(unsigned int)(cp[14] & 0xf), (unsigned int)(cp[14] >> 4),
(unsigned int)(cp[13] & 0xf), (unsigned int)(cp[13] >> 4),
(unsigned int)(cp[12] & 0xf), (unsigned int)(cp[12] >> 4),
(unsigned int)(cp[11] & 0xf), (unsigned int)(cp[11] >> 4),
(unsigned int)(cp[10] & 0xf), (unsigned int)(cp[10] >> 4),
(unsigned int)(cp[9] & 0xf), (unsigned int)(cp[9] >> 4),
(unsigned int)(cp[8] & 0xf), (unsigned int)(cp[8] >> 4),
(unsigned int)(cp[7] & 0xf), (unsigned int)(cp[7] >> 4),
(unsigned int)(cp[6] & 0xf), (unsigned int)(cp[6] >> 4),
(unsigned int)(cp[5] & 0xf), (unsigned int)(cp[5] >> 4),
(unsigned int)(cp[4] & 0xf), (unsigned int)(cp[4] >> 4),
(unsigned int)(cp[3] & 0xf), (unsigned int)(cp[3] >> 4),
(unsigned int)(cp[2] & 0xf), (unsigned int)(cp[2] >> 4),
(unsigned int)(cp[1] & 0xf), (unsigned int)(cp[1] >> 4),
(unsigned int)(cp[0] & 0xf), (unsigned int)(cp[0] >> 4));
}
#endif
request->type = T_PTR;
query_name(request);
}
/*
* query_name - generate a query based on class, type and name.
*/
static void query_name(struct reslist *request)
{
char buf[MAXPACKET];
int request_len = 0;
int ns;
memset(buf, 0, sizeof(buf));
if ((request_len =
irc_res_mkquery(request->queryname, C_IN, request->type, (unsigned char *)buf, sizeof(buf))) > 0)
{
HEADER *header = (HEADER *)(void *)buf;
header->id = request->id;
++request->sends;
ns = send_res_msg(buf, request_len, request->sends);
if (ns != -1)
request->lastns = ns;
}
}
static void resend_query(struct reslist *request)
{
if (--request->retries <= 0)
{
(*request->query->callback) (request->query->ptr, NULL);
rem_request(request);
return;
}
switch (request->type)
{
case T_PTR:
do_query_number(NULL, &request->addr, request);
break;
case T_A:
#ifdef RB_IPV6
case T_AAAA:
#endif
do_query_name(NULL, request->name, request, request->type);
break;
default:
break;
}
}
/*
* check_question - check if the reply really belongs to the
* name we queried (to guard against late replies from previous
* queries with the same id).
*/
static int check_question(struct reslist *request, HEADER * header, char *buf, char *eob)
{
char hostbuf[IRCD_RES_HOSTLEN + 1]; /* working buffer */
unsigned char *current; /* current position in buf */
int n; /* temp count */
current = (unsigned char *)buf + sizeof(HEADER);
if (header->qdcount != 1)
return 0;
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, hostbuf,
sizeof(hostbuf));
if (n <= 0)
return 0;
if (strcasecmp(hostbuf, request->queryname))
return 0;
return 1;
}
/*
* proc_answer - process name server reply
*/
static int proc_answer(struct reslist *request, HEADER * header, char *buf, char *eob)
{
char hostbuf[IRCD_RES_HOSTLEN + 100]; /* working buffer */
unsigned char *current; /* current position in buf */
int type; /* answer type */
int n; /* temp count */
int rd_length;
struct sockaddr_in *v4; /* conversion */
#ifdef RB_IPV6
struct sockaddr_in6 *v6;
#endif
current = (unsigned char *)buf + sizeof(HEADER);
for (; header->qdcount > 0; --header->qdcount)
{
if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0)
return 0;
current += (size_t) n + QFIXEDSZ;
}
/*
* process each answer sent to us blech.
*/
while (header->ancount > 0 && (char *)current < eob)
{
header->ancount--;
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, hostbuf,
sizeof(hostbuf));
if (n < 0)
{
/*
* broken message
*/
return (0);
}
else if (n == 0)
{
/*
* no more answers left
*/
return (0);
}
hostbuf[IRCD_RES_HOSTLEN] = '\0';
/* With Address arithmetic you have to be very anal
* this code was not working on alpha due to that
* (spotted by rodder/jailbird/dianora)
*/
current += (size_t) n;
if (!(((char *)current + ANSWER_FIXED_SIZE) < eob))
break;
type = irc_ns_get16(current);
current += TYPE_SIZE;
(void) irc_ns_get16(current);
current += CLASS_SIZE;
request->ttl = irc_ns_get32(current);
current += TTL_SIZE;
rd_length = irc_ns_get16(current);
current += RDLENGTH_SIZE;
/*
* Wait to set request->type until we verify this structure
*/
switch (type)
{
case T_A:
if (request->type != T_A)
return (0);
/*
* check for invalid rd_length or too many addresses
*/
if (rd_length != sizeof(struct in_addr))
return (0);
v4 = (struct sockaddr_in *)&request->addr;
SET_SS_LEN(&request->addr, sizeof(struct sockaddr_in));
v4->sin_family = AF_INET;
memcpy(&v4->sin_addr, current, sizeof(struct in_addr));
return (1);
break;
#ifdef RB_IPV6
case T_AAAA:
if (request->type != T_AAAA)
return (0);
if (rd_length != sizeof(struct in6_addr))
return (0);
SET_SS_LEN(&request->addr, sizeof(struct sockaddr_in6));
v6 = (struct sockaddr_in6 *)&request->addr;
v6->sin6_family = AF_INET6;
memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr));
return (1);
break;
#endif
case T_PTR:
if (request->type != T_PTR)
return (0);
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current,
hostbuf, sizeof(hostbuf));
if (n < 0)
return (0); /* broken message */
else if (n == 0)
return (0); /* no more answers left */
rb_strlcpy(request->name, hostbuf, IRCD_RES_HOSTLEN + 1);
return (1);
break;
case T_CNAME:
/* real answer will follow */
current += rd_length;
break;
default:
break;
}
}
return (1);
}
/*
* res_read_single_reply - read a dns reply from the nameserver and process it.
* Return value: 1 if a packet was read, 0 otherwise
*/
static int res_read_single_reply(rb_fde_t *F, void *data)
{
char buf[sizeof(HEADER) + MAXPACKET]
/* Sparc and alpha need 16bit-alignment for accessing header->id
* (which is uint16_t). Because of the header = (HEADER*) buf;
* lateron, this is neeeded. --FaUl
*/
#if defined(__sparc__) || defined(__alpha__)
__attribute__ ((aligned(16)))
#endif
;
HEADER *header;
struct reslist *request = NULL;
struct DNSReply *reply = NULL;
int rc;
int answer_count;
socklen_t len = sizeof(struct rb_sockaddr_storage);
struct rb_sockaddr_storage lsin;
int ns;
rc = recvfrom(rb_get_fd(F), buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len);
/* No packet */
if (rc == 0 || rc == -1)
return 0;
/* Too small */
if (rc <= (int)(sizeof(HEADER)))
return 1;
/*
* convert DNS reply reader from Network byte order to CPU byte order.
*/
header = (HEADER *)(void *)buf;
header->ancount = ntohs(header->ancount);
header->qdcount = ntohs(header->qdcount);
header->nscount = ntohs(header->nscount);
header->arcount = ntohs(header->arcount);
/*
* response for an id which we have already received an answer for
* just ignore this response.
*/
if (0 == (request = find_id(header->id)))
return 1;
/*
* check against possibly fake replies
*/
ns = res_ourserver(&lsin);
if (ns == -1)
return 1;
if (ns != request->lastns)
{
/*
* We'll accept the late reply, but penalize it a little more to make
* sure a laggy server doesn't end up favored.
*/
ns_failure_count[ns] += 3;
}
if (!check_question(request, header, buf, buf + rc))
return 1;
if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
{
/*
* RFC 2136 states that in the event of a server returning SERVFAIL
* or NOTIMP, the request should be resent to the next server.
* Additionally, if the server refuses our query, resend it as well.
* -- mr_flea
*/
if (SERVFAIL == header->rcode || NOTIMP == header->rcode ||
REFUSED == header->rcode)
{
ns_failure_count[ns]++;
resend_query(request);
}
else
{
/*
* Either a fatal error was returned or no answer. Cancel the
* request.
*/
if (NXDOMAIN == header->rcode)
{
/* If the rcode is NXDOMAIN, treat it as a good response. */
ns_failure_count[ns] /= 4;
}
(*request->query->callback) (request->query->ptr, NULL);
rem_request(request);
}
return 1;
}
/*
* If this fails there was an error decoding the received packet.
* -- jilles
*/
answer_count = proc_answer(request, header, buf, buf + rc);
if (answer_count)
{
if (request->type == T_PTR)
{
if (request->name == NULL)
{
/*
* Got a PTR response with no name, something strange is
* happening. Try another DNS server.
*/
ns_failure_count[ns]++;
resend_query(request);
return 1;
}
/*
* Lookup the 'authoritative' name that we were given for the
* ip#.
*/
#ifdef RB_IPV6
if (request->addr.ss_family == AF_INET6)
gethost_byname_type_fqdn(request->name, request->query, T_AAAA);
else
#endif
gethost_byname_type_fqdn(request->name, request->query, T_A);
rem_request(request);
}
else
{
/*
* got a name and address response, client resolved
*/
reply = make_dnsreply(request);
(*request->query->callback) (request->query->ptr, reply);
rb_free(reply);
rem_request(request);
}
ns_failure_count[ns] /= 4;
}
else
{
/* Invalid or corrupt reply - try another resolver. */
ns_failure_count[ns]++;
resend_query(request);
}
return 1;
}
static void
res_readreply(rb_fde_t *F, void *data)
{
while (res_read_single_reply(F, data))
;
rb_setselect(F, RB_SELECT_READ, res_readreply, NULL);
}
static struct DNSReply *
make_dnsreply(struct reslist *request)
{
struct DNSReply *cp;
lrb_assert(request != 0);
cp = (struct DNSReply *)rb_malloc(sizeof(struct DNSReply));
cp->h_name = request->name;
memcpy(&cp->addr, &request->addr, sizeof(cp->addr));
return (cp);
}

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/*
* res.h for referencing functions in res.c, reslib.c
*
* $Id: res.h 2023 2006-09-02 23:47:27Z jilles $
*/
#ifndef _CHARYBDIS_RES_H
#define _CHARYBDIS_RES_H
/* Maximum number of nameservers in /etc/resolv.conf we care about
* In hybrid, this was 2 -- but in Charybdis, we want to track
* a few more than that ;) --nenolod
*/
#define IRCD_MAXNS 10
#define RESOLVER_HOSTLEN 255
struct DNSReply
{
char *h_name;
struct rb_sockaddr_storage addr;
};
struct DNSQuery
{
void *ptr; /* pointer used by callback to identify request */
void (*callback)(void* vptr, struct DNSReply *reply); /* callback to call */
};
extern struct rb_sockaddr_storage irc_nsaddr_list[];
extern int irc_nscount;
extern void init_resolver(void);
extern void restart_resolver(void);
extern void gethost_byname_type(const char *, struct DNSQuery *, int);
extern void gethost_byaddr(const struct rb_sockaddr_storage *, struct DNSQuery *);
#endif

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/*
* include/irc_reslib.h
*
* $Id: reslib.h 446 2006-02-12 02:46:54Z db $
*/
#ifndef _CHARYBDIS_RESLIB_H
#define _CHARYBDIS_RESLIB_H
/* Longest hostname we're willing to work with.
* Due to DNSBLs this is more than HOSTLEN.
*/
#define IRCD_RES_HOSTLEN 255
/* Here we define some values lifted from nameser.h */
#define NS_NOTIFY_OP 4
#define NS_INT16SZ 2
#define NS_IN6ADDRSZ 16
#define NS_INADDRSZ 4
#define NS_INT32SZ 4
#define NS_CMPRSFLGS 0xc0
#define NS_MAXCDNAME 255
#define QUERY 0
#define IQUERY 1
#define NO_ERRORS 0
#define SERVFAIL 2
#define NXDOMAIN 3
#define NOTIMP 4
#define REFUSED 5
#define T_A 1
#define T_AAAA 28
#define T_PTR 12
#define T_CNAME 5
#define T_NULL 10
#define C_IN 1
#define QFIXEDSZ 4
#define RRFIXEDSZ 10
#define HFIXEDSZ 12
typedef struct
{
unsigned id :16; /* query identification number */
#ifdef WORDS_BIGENDIAN
/* fields in third byte */
unsigned qr: 1; /* response flag */
unsigned opcode: 4; /* purpose of message */
unsigned aa: 1; /* authoritive answer */
unsigned tc: 1; /* truncated message */
unsigned rd: 1; /* recursion desired */
/* fields in fourth byte */
unsigned ra: 1; /* recursion available */
unsigned unused :1; /* unused bits (MBZ as of 4.9.3a3) */
unsigned ad: 1; /* authentic data from named */
unsigned cd: 1; /* checking disabled by resolver */
unsigned rcode :4; /* response code */
#else
/* fields in third byte */
unsigned rd :1; /* recursion desired */
unsigned tc :1; /* truncated message */
unsigned aa :1; /* authoritive answer */
unsigned opcode :4; /* purpose of message */
unsigned qr :1; /* response flag */
/* fields in fourth byte */
unsigned rcode :4; /* response code */
unsigned cd: 1; /* checking disabled by resolver */
unsigned ad: 1; /* authentic data from named */
unsigned unused :1; /* unused bits (MBZ as of 4.9.3a3) */
unsigned ra :1; /* recursion available */
#endif
/* remaining bytes */
unsigned qdcount :16; /* number of question entries */
unsigned ancount :16; /* number of answer entries */
unsigned nscount :16; /* number of authority entries */
unsigned arcount :16; /* number of resource entries */
} HEADER;
/*
* Inline versions of get/put short/long. Pointer is advanced.
*/
#define IRC_NS_GET16(s, cp) { \
const unsigned char *t_cp = (const unsigned char *)(cp); \
(s) = ((u_int16_t)t_cp[0] << 8) \
| ((u_int16_t)t_cp[1]) \
; \
(cp) += NS_INT16SZ; \
}
#define IRC_NS_GET32(l, cp) { \
const unsigned char *t_cp = (const unsigned char *)(cp); \
(l) = ((u_int32_t)t_cp[0] << 24) \
| ((u_int32_t)t_cp[1] << 16) \
| ((u_int32_t)t_cp[2] << 8) \
| ((u_int32_t)t_cp[3]) \
; \
(cp) += NS_INT32SZ; \
}
#define IRC_NS_PUT16(s, cp) { \
u_int16_t t_s = (u_int16_t)(s); \
unsigned char *t_cp = (unsigned char *)(cp); \
*t_cp++ = t_s >> 8; \
*t_cp = t_s; \
(cp) += NS_INT16SZ; \
}
#define IRC_NS_PUT32(l, cp) { \
u_int32_t t_l = (u_int32_t)(l); \
unsigned char *t_cp = (unsigned char *)(cp); \
*t_cp++ = t_l >> 24; \
*t_cp++ = t_l >> 16; \
*t_cp++ = t_l >> 8; \
*t_cp = t_l; \
(cp) += NS_INT32SZ; \
}
extern int irc_res_init(void);
extern int irc_dn_expand(const unsigned char *msg, const unsigned char *eom, const unsigned char *src, char *dst, int dstsiz);
extern int irc_dn_skipname(const unsigned char *ptr, const unsigned char *eom);
extern unsigned int irc_ns_get16(const unsigned char *src);
extern unsigned long irc_ns_get32(const unsigned char *src);
extern void irc_ns_put16(unsigned int src, unsigned char *dst);
extern void irc_ns_put32(unsigned long src, unsigned char *dst);
extern int irc_res_mkquery(const char *dname, int class, int type, unsigned char *buf, int buflen);
extern char irc_domain[IRCD_RES_HOSTLEN + 1];
#endif