--- /dev/null
+/*
+ * 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 $Id$
+ */
+
+#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);
+ 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);
+
+ 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;
+}
projects / ircu2.10.12-pk.git / blobdiff