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ircu2/ircd/ircd_res.c

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/*
* A rewrite of Darren Reed's original res.c As there is nothing
* left of Darren's 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.
*
* 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
*/
/** @file
* @brief IRC resolver functions.
* @version $Id: ircd_res.c 1764 2007-02-25 15:41:49Z entrope $
*/
#include "client.h"
#include "ircd_alloc.h"
#include "ircd_log.h"
#include "ircd_osdep.h"
#include "ircd_reply.h"
#include "ircd_string.h"
#include "ircd_snprintf.h"
#include "ircd.h"
#include "numeric.h"
#include "fileio.h" /* for fbopen / fbclose / fbputs */
#include "random.h"
#include "s_bsd.h"
#include "s_debug.h"
#include "s_stats.h"
#include "send.h"
#include "sys.h"
#include "res.h"
#include "ircd_reslib.h"
/* #include <assert.h> -- Now using assert in ircd_log.h */
#include <string.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <time.h>
#if (CHAR_BIT != 8)
#error this code needs to be able to address individual octets
#endif
/** IPv4 resolver UDP socket. */
static struct Socket res_socket_v4;
/** IPv6 resolver UDP socket. */
static struct Socket res_socket_v6;
/** Next DNS lookup timeout. */
static struct Timer res_timeout;
/** Local address for IPv4 DNS lookups. */
struct irc_sockaddr VirtualHost_dns_v4;
/** Local address for IPv6 DNS lookups. */
struct irc_sockaddr VirtualHost_dns_v6;
/** Check for whether the resolver has been initialized yet. */
#define resolver_started() (request_list.next != NULL)
/** Maximum DNS packet length.
* RFC says 512, but we add extra for expanded names.
*/
#define MAXPACKET 1024
#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.
*/
/** Size of TYPE field of a DNS RR header. */
#define TYPE_SIZE (size_t)2
/** Size of CLASS field of a DNS RR header. */
#define CLASS_SIZE (size_t)2
/** Size of TTL field of a DNS RR header. */
#define TTL_SIZE (size_t)4
/** Size of RDLENGTH field of a DNS RR header. */
#define RDLENGTH_SIZE (size_t)2
/** Size of fixed-format part of a DNS RR header. */
#define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE)
/** Current request state. */
typedef enum
{
REQ_IDLE, /**< We're doing not much at all. */
REQ_PTR, /**< Looking up a PTR. */
REQ_A, /**< Looking up an A, possibly because AAAA failed. */
REQ_AAAA, /**< Looking up an AAAA. */
REQ_CNAME, /**< We got a CNAME in response, we better get a real answer next. */
REQ_INT /**< ip6.arpa failed, falling back to ip6.int. */
} request_state;
/** Doubly linked list node. */
struct dlink
{
struct dlink *prev; /**< Previous element in list. */
struct dlink *next; /**< Next element in list. */
};
/** A single resolver request.
* (Do not be fooled by the "list" in the name.)
*/
struct reslist
{
struct dlink node; /**< Doubly linked list node. */
int id; /**< Request ID (from request header). */
int sent; /**< Number of requests sent. */
request_state state; /**< State the resolver machine is in. */
char type; /**< Current request type. */
char retries; /**< Retry counter. */
char sends; /**< Number of sends (>1 means resent). */
char resend; /**< Send flag; 0 == don't resend. */
time_t sentat; /**< Timestamp we last sent this request. */
time_t timeout; /**< When this request times out. */
struct irc_in_addr addr; /**< Address for this request. */
char *name; /**< Hostname for this request. */
dns_callback_f callback; /**< Callback function on completion. */
void *callback_ctx; /**< Context pointer for callback. */
};
/** Base of request list. */
static struct dlink request_list;
static void rem_request(struct reslist *request);
static struct reslist *make_request(dns_callback_f callback, void *ctx);
static void do_query_name(dns_callback_f callback, void *ctx,
const char* name, struct reslist *request, int);
static void do_query_number(dns_callback_f callback, void *ctx,
const struct irc_in_addr *,
struct reslist *request);
static void query_name(const char *name, int query_class, int query_type,
struct reslist *request);
static int send_res_msg(const char *buf, int len, int count);
static void resend_query(struct reslist *request);
static int proc_answer(struct reslist *request, HEADER *header, char *, char *);
static struct reslist *find_id(int id);
static void res_readreply(struct Event *ev);
static void timeout_resolver(struct Event *notused);
extern struct irc_sockaddr irc_nsaddr_list[IRCD_MAXNS];
extern int irc_nscount;
extern char irc_domain[HOSTLEN];
/** Prepare the resolver library to (optionally) accept a list of
* DNS servers through add_dns_server().
*/
void clear_nameservers(void)
{
irc_nscount = 0;
memset(&VirtualHost_dns_v4, 0, sizeof(VirtualHost_dns_v4));
memset(&VirtualHost_dns_v6, 0, sizeof(VirtualHost_dns_v6));
}
/** Check whether \a inp is a nameserver we use.
* @param[in] inp Nameserver address.
* @return Non-zero if we trust \a inp; zero if not.
*/
static int
res_ourserver(const struct irc_sockaddr *inp)
{
int ns;
for (ns = 0; ns < irc_nscount; ns++)
if (!irc_in_addr_cmp(&inp->addr, &irc_nsaddr_list[ns].addr)
&& inp->port == irc_nsaddr_list[ns].port)
return 1;
return(0);
}
/** Start (or re-start) resolver.
* This means read resolv.conf, initialize the list of pending
* requests, open the resolver socket and initialize its timeout.
*/
void
restart_resolver(void)
{
int need_v4;
int need_v6;
int ns;
irc_res_init();
if (!request_list.next)
request_list.next = request_list.prev = &request_list;
/* Check which address family (or families) our nameservers use. */
for (need_v4 = need_v6 = ns = 0; ns < irc_nscount; ns++)
{
if (irc_in_addr_is_ipv4(&irc_nsaddr_list[ns].addr))
need_v4 = 1;
else
need_v6 = 1;
}
/* If we need an IPv4 socket, and don't have one, open it. */
if (need_v4 && !s_active(&res_socket_v4))
{
int fd = os_socket(&VirtualHost_dns_v4, SOCK_DGRAM, "Resolver UDPv4 socket", AF_INET);
if (fd >= 0)
socket_add(&res_socket_v4, res_readreply, NULL,
SS_DATAGRAM, SOCK_EVENT_READABLE, fd);
}
#ifdef AF_INET6
/* If we need an IPv6 socket, and don't have one, open it. */
if (need_v6 && !s_active(&res_socket_v6))
{
int fd = os_socket(&VirtualHost_dns_v6, SOCK_DGRAM, "Resolver UDPv6 socket", AF_INET6);
if (fd >= 0)
socket_add(&res_socket_v6, res_readreply, NULL,
SS_DATAGRAM, SOCK_EVENT_READABLE, fd);
}
#endif
if (s_active(&res_socket_v4) || s_active(&res_socket_v6))
timer_init(&res_timeout);
}
/** Append local domain to hostname if needed.
* If \a hname does not contain any '.'s, append #irc_domain to it.
* @param[in,out] hname Hostname to check.
* @param[in] size Length of \a hname buffer.
*/
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);
}
}
}
}
/** Add a node to a doubly linked list.
* @param[in,out] node Node to add to list.
* @param[in,out] next Add \a node before this one.
*/
static void
add_dlink(struct dlink *node, struct dlink *next)
{
node->prev = next->prev;
node->next = next;
node->prev->next = node;
node->next->prev = node;
}
/** Remove a request from the list and free it.
* @param[in] request Node to free.
*/
static void
rem_request(struct reslist *request)
{
/* remove from dlist */
request->node.prev->next = request->node.next;
request->node.next->prev = request->node.prev;
/* free memory */
MyFree(request->name);
MyFree(request);
}
/** Create a DNS request record for the server.
* @param[in] query Callback information for caller.
* @return Newly allocated and linked-in reslist.
*/
static struct reslist *
make_request(dns_callback_f callback, void *ctx)
{
struct reslist *request;
if (!resolver_started())
restart_resolver();
request = (struct reslist *)MyMalloc(sizeof(struct reslist));
memset(request, 0, sizeof(struct reslist));
request->state = REQ_IDLE;
request->sentat = CurrentTime;
request->retries = feature_int(FEAT_IRCD_RES_RETRIES);
request->resend = 1;
request->timeout = feature_int(FEAT_IRCD_RES_TIMEOUT);
memset(&request->addr, 0, sizeof(request->addr));
request->callback = callback;
request->callback_ctx = ctx;
add_dlink(&request->node, &request_list);
return(request);
}
/** Make sure that a timeout event will happen by the given time.
* @param[in] when Latest time for timeout to run.
*/
static void
check_resolver_timeout(time_t when)
{
if (when > CurrentTime + AR_TTL)
when = CurrentTime + AR_TTL;
/* TODO after 2.10.12: Rewrite the timer API because there should be
* no need for clients to know this kind of implementation detail. */
if (when > t_expire(&res_timeout))
/* do nothing */;
else if (t_onqueue(&res_timeout) && !(res_timeout.t_header.gh_flags & GEN_MARKED))
timer_chg(&res_timeout, TT_ABSOLUTE, when);
else
timer_add(&res_timeout, timeout_resolver, NULL, TT_ABSOLUTE, when);
}
/** Drop pending DNS lookups which have timed out.
* @param[in] ev Timer event data (ignored).
*/
static void
timeout_resolver(struct Event *ev)
{
struct dlink *ptr, *next_ptr;
struct reslist *request;
time_t next_time = 0;
time_t timeout = 0;
if (ev_type(ev) != ET_EXPIRE)
return;
for (ptr = request_list.next; ptr != &request_list; ptr = next_ptr)
{
next_ptr = ptr->next;
request = (struct reslist*)ptr;
timeout = request->sentat + request->timeout;
if (CurrentTime >= timeout)
{
if (--request->retries <= 0)
{
Debug((DEBUG_DNS, "Request %p out of retries; destroying", request));
(*request->callback)(request->callback_ctx, NULL, NULL);
rem_request(request);
continue;
}
else
{
request->sentat = CurrentTime;
request->timeout += request->timeout;
resend_query(request);
}
}
if ((next_time == 0) || timeout < next_time)
{
next_time = timeout;
}
}
if (next_time <= CurrentTime)
next_time = CurrentTime + AR_TTL;
check_resolver_timeout(next_time);
}
/** Drop queries that are associated with a particular pointer.
* This is used to clean up lookups for clients or conf blocks
* that went away.
* @param[in] vptr User callback pointer to search for.
*/
void
delete_resolver_queries(const void *vptr)
{
struct dlink *ptr, *next_ptr;
struct reslist *request;
if (request_list.next) {
for (ptr = request_list.next; ptr != &request_list; ptr = next_ptr)
{
next_ptr = ptr->next;
request = (struct reslist*)ptr;
if (vptr == request->callback_ctx) {
Debug((DEBUG_DNS, "Removing request %p with vptr %p", request, vptr));
rem_request(request);
}
}
}
}
/** Send a message to all of our nameservers.
* @param[in] msg Message to send.
* @param[in] len Length of message.
* @param[in] rcount Maximum number of servers to ask.
* @return Number of servers that were successfully asked.
*/
static int
send_res_msg(const char *msg, int len, int rcount)
{
int i;
int sent = 0;
int max_queries = IRCD_MIN(irc_nscount, rcount);
/* RES_PRIMARY option is not implemented
* if (res.options & RES_PRIMARY || 0 == max_queries)
*/
if (max_queries == 0)
max_queries = 1;
for (i = 0; i < max_queries; i++) {
int fd = irc_in_addr_is_ipv4(&irc_nsaddr_list[i].addr) ? s_fd(&res_socket_v4) : s_fd(&res_socket_v6);
if (os_sendto_nonb(fd, msg, len, NULL, 0, &irc_nsaddr_list[i]) == IO_SUCCESS)
++sent;
}
return(sent);
}
/** Find a DNS request by ID.
* @param[in] id Identifier to find.
* @return Matching DNS request, or NULL if none are found.
*/
static struct reslist *
find_id(int id)
{
struct dlink *ptr;
struct reslist *request;
for (ptr = request_list.next; ptr != &request_list; ptr = ptr->next)
{
request = (struct reslist*)ptr;
if (request->id == id) {
Debug((DEBUG_DNS, "find_id(%d) -> %p", id, request));
return(request);
}
}
Debug((DEBUG_DNS, "find_id(%d) -> NULL", id));
return(NULL);
}
/** Try to look up address for a hostname, trying IPv6 (T_AAAA) first.
* @param[in] name Hostname to look up.
* @param[in] query Callback information.
*/
void
gethost_byname(const char *name, dns_callback_f callback, void *ctx)
{
do_query_name(callback, ctx, name, NULL, T_AAAA);
}
/** Try to look up hostname for an address.
* @param[in] addr Address to look up.
* @param[in] query Callback information.
*/
void
gethost_byaddr(const struct irc_in_addr *addr, dns_callback_f callback, void *ctx)
{
do_query_number(callback, ctx, addr, NULL);
}
/** Send a query to look up the address for a name.
* @param[in] query Callback information.
* @param[in] name Hostname to look up.
* @param[in] request DNS lookup structure (may be NULL).
* @param[in] type Preferred request type.
*/
static void
do_query_name(dns_callback_f callback, void *ctx, const char *name,
struct reslist *request, int type)
{
char host_name[HOSTLEN + 1];
ircd_strncpy(host_name, name, HOSTLEN + 1);
add_local_domain(host_name, HOSTLEN);
if (request == NULL)
{
request = make_request(callback, ctx);
DupString(request->name, host_name);
#ifdef IPV6
if (type != T_A)
request->state = REQ_AAAA;
else
#endif
request->state = REQ_A;
}
request->type = type;
Debug((DEBUG_DNS, "Requesting DNS %s %s as %p", (request->state == REQ_AAAA ? "AAAA" : "A"), host_name, request));
query_name(host_name, C_IN, type, request);
}
/** Send a query to look up the name for an address.
* @param[in] query Callback information.
* @param[in] addr Address to look up.
* @param[in] request DNS lookup structure (may be NULL).
*/
static void
do_query_number(dns_callback_f callback, void *ctx, const struct irc_in_addr *addr,
struct reslist *request)
{
char ipbuf[128];
const unsigned char *cp;
if (irc_in_addr_is_ipv4(addr))
{
cp = (const unsigned char*)&addr->in6_16[6];
ircd_snprintf(NULL, ipbuf, sizeof(ipbuf), "%u.%u.%u.%u.in-addr.arpa.",
(unsigned int)(cp[3]), (unsigned int)(cp[2]),
(unsigned int)(cp[1]), (unsigned int)(cp[0]));
}
else
{
const char *intarpa;
if (request != NULL && request->state == REQ_INT)
intarpa = "int";
else
intarpa = "arpa";
cp = (const unsigned char *)&addr->in6_16[0];
ircd_snprintf(NULL, ipbuf, sizeof(ipbuf),
"%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.%s.",
(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), intarpa);
}
if (request == NULL)
{
request = make_request(callback, ctx);
request->state= REQ_PTR;
request->type = T_PTR;
memcpy(&request->addr, addr, sizeof(request->addr));
request->name = (char *)MyMalloc(HOSTLEN + 1);
}
Debug((DEBUG_DNS, "Requesting DNS PTR %s as %p", ipbuf, request));
query_name(ipbuf, C_IN, T_PTR, request);
}
/** Generate a query based on class, type and name.
* @param[in] name Domain name to look up.
* @param[in] query_class Query class (see RFC 1035).
* @param[in] type Query type (see RFC 1035).
* @param[in] request DNS request structure.
*/
static void
query_name(const char *name, int query_class, int type,
struct reslist *request)
{
char buf[MAXPACKET];
int request_len = 0;
memset(buf, 0, sizeof(buf));
if ((request_len = irc_res_mkquery(name, query_class, type,
(unsigned char *)buf, sizeof(buf))) > 0)
{
HEADER *header = (HEADER *)buf;
/*
* generate an 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
*/
do
{
header->id = (header->id + ircrandom()) & 0xffff;
} while (find_id(header->id));
request->id = header->id;
++request->sends;
request->sent += send_res_msg(buf, request_len, request->sends);
check_resolver_timeout(request->sentat + request->timeout);
}
}
/** Send a failed DNS lookup request again.
* @param[in] request Request to resend.
*/
static void
resend_query(struct reslist *request)
{
if (request->resend == 0)
return;
switch(request->type)
{
case T_PTR:
do_query_number(NULL, NULL, &request->addr, request);
break;
case T_A:
do_query_name(NULL, NULL, request->name, request, request->type);
break;
case T_AAAA:
/* didn't work, try A */
if (request->state == REQ_AAAA)
do_query_name(NULL, NULL, request->name, request, T_A);
default:
break;
}
}
/** Process the answer for a lookup request.
* @param[in] request DNS request that got an answer.
* @param[in] header Header of DNS response.
* @param[in] buf DNS response body.
* @param[in] eob Pointer to end of DNS response.
* @return Number of answers read from \a buf.
*/
static int
proc_answer(struct reslist *request, HEADER* header, char* buf, char* eob)
{
char hostbuf[HOSTLEN + 100]; /* working buffer */
unsigned char *current; /* current position in buf */
int type; /* answer type */
int n; /* temp count */
int rd_length;
current = (unsigned char *)buf + sizeof(HEADER);
for (; header->qdcount > 0; --header->qdcount)
{
if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0)
break;
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[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;
/* We do not use the class or TTL values. */
current += CLASS_SIZE;
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);
memset(&request->addr, 0, sizeof(request->addr));
memcpy(&request->addr.in6_16[6], current, sizeof(struct in_addr));
return(1);
break;
case T_AAAA:
if (request->type != T_AAAA)
return(0);
if (rd_length != sizeof(struct irc_in_addr))
return(0);
memcpy(&request->addr, current, sizeof(struct irc_in_addr));
return(1);
break;
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 */
ircd_strncpy(request->name, hostbuf, HOSTLEN + 1);
return(1);
break;
case T_CNAME: /* first check we already haven't started looking
into a cname */
if (request->state == REQ_CNAME)
{
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob,
current, hostbuf, sizeof(hostbuf));
if (n < 0)
return(0);
return(1);
}
request->state = REQ_CNAME;
current += rd_length;
break;
default:
/* XXX I'd rather just throw away the entire bogus thing
* but its possible its just a broken nameserver with still
* valid answers. But lets do some rudimentary logging for now...
*/
log_write(LS_RESOLVER, L_ERROR, 0, "irc_res.c bogus type %d", type);
if ((char*)current + rd_length >= (char*)current)
current += rd_length;
else
return(0);
break;
}
}
return(1);
}
/** Read a DNS reply from the nameserver and process it.
* @param[in] ev I/O activity event for resolver socket.
*/
static void
res_readreply(struct Event *ev)
{
struct irc_sockaddr lsin;
struct Socket *sock;
char buf[sizeof(HEADER) + MAXPACKET];
HEADER *header;
struct reslist *request = NULL;
unsigned int rc;
int answer_count;
assert((ev_socket(ev) == &res_socket_v4) || (ev_socket(ev) == &res_socket_v6));
sock = ev_socket(ev);
if (IO_SUCCESS != os_recvfrom_nonb(s_fd(sock), buf, sizeof(buf), &rc, &lsin)
|| (rc <= sizeof(HEADER)))
return;
/*
* check against possibly fake replies
*/
if (!res_ourserver(&lsin))
return;
/*
* convert DNS reply reader from Network byte order to CPU byte order.
*/
header = (HEADER *)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;
if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
{
if (SERVFAIL == header->rcode || NXDOMAIN == header->rcode)
{
/*
* If a bad error was returned, we stop here and don't send
* send any more (no retries granted).
*/
Debug((DEBUG_DNS, "Request %p has bad response (state %d type %d rcode %d)", request, request->state, request->type, header->rcode));
(*request->callback)(request->callback_ctx, NULL, NULL);
rem_request(request);
}
else
{
/*
* If we haven't already tried this, and we're looking up AAAA, try A
* now
*/
if (request->state == REQ_AAAA && request->type == T_AAAA)
{
request->timeout += feature_int(FEAT_IRCD_RES_TIMEOUT);
resend_query(request);
}
else if (request->type == T_PTR && request->state != REQ_INT &&
!irc_in_addr_is_ipv4(&request->addr))
{
request->state = REQ_INT;
request->timeout += feature_int(FEAT_IRCD_RES_TIMEOUT);
resend_query(request);
}
}
return;
}
/*
* If this fails there was an error decoding the received packet,
* try it again and hope it works the next time.
*/
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 bogus is happening
* don't bother trying again, the client address doesn't resolve
*/
Debug((DEBUG_DNS, "Request %p PTR had empty name", request));
(*request->callback)(request->callback_ctx, NULL, NULL);
rem_request(request);
return;
}
/*
* Lookup the 'authoritative' name that we were given for the
* ip#.
*/
#ifdef IPV6
if (!irc_in_addr_is_ipv4(&request->addr))
do_query_name(request->callback, request->callback_ctx, request->name, NULL, T_AAAA);
else
#endif
do_query_name(request->callback, request->callback_ctx, request->name, NULL, T_A);
Debug((DEBUG_DNS, "Request %p switching to forward resolution", request));
rem_request(request);
}
else
{
/*
* got a name and address response, client resolved
*/
(*request->callback)(request->callback_ctx, &request->addr, request->name);
Debug((DEBUG_DNS, "Request %p got forward resolution", request));
rem_request(request);
}
}
else if (!request->sent)
{
/* XXX - we got a response for a query we didn't send with a valid id?
* this should never happen, bail here and leave the client unresolved
*/
assert(0);
/* XXX don't leak it */
Debug((DEBUG_DNS, "Request %p was unexpected(!)", request));
rem_request(request);
}
}
/** Statistics callback to list DNS servers.
* @param[in] source_p Client requesting statistics.
* @param[in] sd Stats descriptor for request (ignored).
* @param[in] param Extra parameter from user (ignored).
*/
void
report_dns_servers(struct Client *source_p, const struct StatDesc *sd, char *param)
{
int i;
char ipaddr[128];
for (i = 0; i < irc_nscount; i++)
{
ircd_ntoa_r(ipaddr, &irc_nsaddr_list[i].addr);
send_reply(source_p, RPL_STATSALINE, ipaddr);
}
}
/** Report memory usage to a client.
* @param[in] sptr Client requesting information.
* @return Total memory used by pending requests.
*/
size_t
cres_mem(struct Client* sptr)
{
struct dlink *dlink;
struct reslist *request;
size_t request_mem = 0;
int request_count = 0;
if (request_list.next) {
for (dlink = request_list.next; dlink != &request_list; dlink = dlink->next) {
request = (struct reslist*)dlink;
request_mem += sizeof(*request);
if (request->name)
request_mem += strlen(request->name) + 1;
++request_count;
}
}
send_reply(sptr, SND_EXPLICIT | RPL_STATSDEBUG,
":Resolver: requests %d(%d)", request_count, request_mem);
return request_mem;
}
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