| Index: third_party/libevent/evdns.c
|
| diff --git a/third_party/libevent/evdns.c b/third_party/libevent/evdns.c
|
| deleted file mode 100644
|
| index 05fe594bc75ed802be6c330bd43ca2c8868ba266..0000000000000000000000000000000000000000
|
| --- a/third_party/libevent/evdns.c
|
| +++ /dev/null
|
| @@ -1,3192 +0,0 @@
|
| -/* $Id: evdns.c 6979 2006-08-04 18:31:13Z nickm $ */
|
| -
|
| -/* The original version of this module was written by Adam Langley; for
|
| - * a history of modifications, check out the subversion logs.
|
| - *
|
| - * When editing this module, try to keep it re-mergeable by Adam. Don't
|
| - * reformat the whitespace, add Tor dependencies, or so on.
|
| - *
|
| - * TODO:
|
| - * - Support IPv6 and PTR records.
|
| - * - Replace all externally visible magic numbers with #defined constants.
|
| - * - Write doccumentation for APIs of all external functions.
|
| - */
|
| -
|
| -/* Async DNS Library
|
| - * Adam Langley <agl@imperialviolet.org>
|
| - * http://www.imperialviolet.org/eventdns.html
|
| - * Public Domain code
|
| - *
|
| - * This software is Public Domain. To view a copy of the public domain dedication,
|
| - * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
|
| - * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
|
| - *
|
| - * I ask and expect, but do not require, that all derivative works contain an
|
| - * attribution similar to:
|
| - * Parts developed by Adam Langley <agl@imperialviolet.org>
|
| - *
|
| - * You may wish to replace the word "Parts" with something else depending on
|
| - * the amount of original code.
|
| - *
|
| - * (Derivative works does not include programs which link against, run or include
|
| - * the source verbatim in their source distributions)
|
| - *
|
| - * Version: 0.1b
|
| - */
|
| -
|
| -#include <sys/types.h>
|
| -#ifdef HAVE_CONFIG_H
|
| -#include "config.h"
|
| -#endif
|
| -
|
| -#ifdef DNS_USE_FTIME_FOR_ID
|
| -#include <sys/timeb.h>
|
| -#endif
|
| -
|
| -#ifndef DNS_USE_CPU_CLOCK_FOR_ID
|
| -#ifndef DNS_USE_GETTIMEOFDAY_FOR_ID
|
| -#ifndef DNS_USE_OPENSSL_FOR_ID
|
| -#ifndef DNS_USE_FTIME_FOR_ID
|
| -#error Must configure at least one id generation method.
|
| -#error Please see the documentation.
|
| -#endif
|
| -#endif
|
| -#endif
|
| -#endif
|
| -
|
| -/* #define _POSIX_C_SOURCE 200507 */
|
| -#ifndef _GNU_SOURCE
|
| -#define _GNU_SOURCE
|
| -#endif
|
| -
|
| -#ifdef DNS_USE_CPU_CLOCK_FOR_ID
|
| -#ifdef DNS_USE_OPENSSL_FOR_ID
|
| -#error Multiple id options selected
|
| -#endif
|
| -#ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
|
| -#error Multiple id options selected
|
| -#endif
|
| -#include <time.h>
|
| -#endif
|
| -
|
| -#ifdef DNS_USE_OPENSSL_FOR_ID
|
| -#ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
|
| -#error Multiple id options selected
|
| -#endif
|
| -#include <openssl/rand.h>
|
| -#endif
|
| -
|
| -#ifndef _FORTIFY_SOURCE
|
| -#define _FORTIFY_SOURCE 3
|
| -#endif
|
| -
|
| -#include <string.h>
|
| -#include <fcntl.h>
|
| -#ifdef HAVE_SYS_TIME_H
|
| -#include <sys/time.h>
|
| -#endif
|
| -#ifdef HAVE_STDINT_H
|
| -#include <stdint.h>
|
| -#endif
|
| -#include <stdlib.h>
|
| -#include <string.h>
|
| -#include <errno.h>
|
| -#include <assert.h>
|
| -#ifdef HAVE_UNISTD_H
|
| -#include <unistd.h>
|
| -#endif
|
| -#include <limits.h>
|
| -#include <sys/stat.h>
|
| -#include <ctype.h>
|
| -#include <stdio.h>
|
| -#include <stdarg.h>
|
| -
|
| -#include "evdns.h"
|
| -#include "evutil.h"
|
| -#include "log.h"
|
| -#ifdef WIN32
|
| -#include <winsock2.h>
|
| -#include <windows.h>
|
| -#include <iphlpapi.h>
|
| -#include <io.h>
|
| -#else
|
| -#include <sys/socket.h>
|
| -#include <netinet/in.h>
|
| -#include <arpa/inet.h>
|
| -#endif
|
| -
|
| -#ifdef HAVE_NETINET_IN6_H
|
| -#include <netinet/in6.h>
|
| -#endif
|
| -
|
| -#define EVDNS_LOG_DEBUG 0
|
| -#define EVDNS_LOG_WARN 1
|
| -
|
| -#ifndef HOST_NAME_MAX
|
| -#define HOST_NAME_MAX 255
|
| -#endif
|
| -
|
| -#include <stdio.h>
|
| -
|
| -#undef MIN
|
| -#define MIN(a,b) ((a)<(b)?(a):(b))
|
| -
|
| -#ifdef __USE_ISOC99B
|
| -/* libevent doesn't work without this */
|
| -typedef ev_uint8_t u_char;
|
| -typedef unsigned int uint;
|
| -#endif
|
| -#include "event.h"
|
| -
|
| -#define u64 ev_uint64_t
|
| -#define u32 ev_uint32_t
|
| -#define u16 ev_uint16_t
|
| -#define u8 ev_uint8_t
|
| -
|
| -#ifdef WIN32
|
| -#define open _open
|
| -#define read _read
|
| -#define close _close
|
| -#define strdup _strdup
|
| -#endif
|
| -
|
| -#define MAX_ADDRS 32 /* maximum number of addresses from a single packet */
|
| -/* which we bother recording */
|
| -
|
| -#define TYPE_A EVDNS_TYPE_A
|
| -#define TYPE_CNAME 5
|
| -#define TYPE_PTR EVDNS_TYPE_PTR
|
| -#define TYPE_AAAA EVDNS_TYPE_AAAA
|
| -
|
| -#define CLASS_INET EVDNS_CLASS_INET
|
| -
|
| -#ifdef HAVE_SETFD
|
| -#define FD_CLOSEONEXEC(x) do { \
|
| - if (fcntl(x, F_SETFD, 1) == -1) \
|
| - event_warn("fcntl(%d, F_SETFD)", x); \
|
| - } while (0)
|
| -#else
|
| -#define FD_CLOSEONEXEC(x) (void)0
|
| -#endif
|
| -
|
| -struct request {
|
| - u8 *request; /* the dns packet data */
|
| - unsigned int request_len;
|
| - int reissue_count;
|
| - int tx_count; /* the number of times that this packet has been sent */
|
| - unsigned int request_type; /* TYPE_PTR or TYPE_A */
|
| - void *user_pointer; /* the pointer given to us for this request */
|
| - evdns_callback_type user_callback;
|
| - struct nameserver *ns; /* the server which we last sent it */
|
| -
|
| - /* elements used by the searching code */
|
| - int search_index;
|
| - struct search_state *search_state;
|
| - char *search_origname; /* needs to be free()ed */
|
| - int search_flags;
|
| -
|
| - /* these objects are kept in a circular list */
|
| - struct request *next, *prev;
|
| -
|
| - struct event timeout_event;
|
| -
|
| - u16 trans_id; /* the transaction id */
|
| - char request_appended; /* true if the request pointer is data which follows this struct */
|
| - char transmit_me; /* needs to be transmitted */
|
| -};
|
| -
|
| -#ifndef HAVE_STRUCT_IN6_ADDR
|
| -struct in6_addr {
|
| - u8 s6_addr[16];
|
| -};
|
| -#endif
|
| -
|
| -struct reply {
|
| - unsigned int type;
|
| - unsigned int have_answer;
|
| - union {
|
| - struct {
|
| - u32 addrcount;
|
| - u32 addresses[MAX_ADDRS];
|
| - } a;
|
| - struct {
|
| - u32 addrcount;
|
| - struct in6_addr addresses[MAX_ADDRS];
|
| - } aaaa;
|
| - struct {
|
| - char name[HOST_NAME_MAX];
|
| - } ptr;
|
| - } data;
|
| -};
|
| -
|
| -struct nameserver {
|
| - int socket; /* a connected UDP socket */
|
| - u32 address;
|
| - u16 port;
|
| - int failed_times; /* number of times which we have given this server a chance */
|
| - int timedout; /* number of times in a row a request has timed out */
|
| - struct event event;
|
| - /* these objects are kept in a circular list */
|
| - struct nameserver *next, *prev;
|
| - struct event timeout_event; /* used to keep the timeout for */
|
| - /* when we next probe this server. */
|
| - /* Valid if state == 0 */
|
| - char state; /* zero if we think that this server is down */
|
| - char choked; /* true if we have an EAGAIN from this server's socket */
|
| - char write_waiting; /* true if we are waiting for EV_WRITE events */
|
| -};
|
| -
|
| -static struct request *req_head = NULL, *req_waiting_head = NULL;
|
| -static struct nameserver *server_head = NULL;
|
| -
|
| -/* Represents a local port where we're listening for DNS requests. Right now, */
|
| -/* only UDP is supported. */
|
| -struct evdns_server_port {
|
| - int socket; /* socket we use to read queries and write replies. */
|
| - int refcnt; /* reference count. */
|
| - char choked; /* Are we currently blocked from writing? */
|
| - char closing; /* Are we trying to close this port, pending writes? */
|
| - evdns_request_callback_fn_type user_callback; /* Fn to handle requests */
|
| - void *user_data; /* Opaque pointer passed to user_callback */
|
| - struct event event; /* Read/write event */
|
| - /* circular list of replies that we want to write. */
|
| - struct server_request *pending_replies;
|
| -};
|
| -
|
| -/* Represents part of a reply being built. (That is, a single RR.) */
|
| -struct server_reply_item {
|
| - struct server_reply_item *next; /* next item in sequence. */
|
| - char *name; /* name part of the RR */
|
| - u16 type : 16; /* The RR type */
|
| - u16 class : 16; /* The RR class (usually CLASS_INET) */
|
| - u32 ttl; /* The RR TTL */
|
| - char is_name; /* True iff data is a label */
|
| - u16 datalen; /* Length of data; -1 if data is a label */
|
| - void *data; /* The contents of the RR */
|
| -};
|
| -
|
| -/* Represents a request that we've received as a DNS server, and holds */
|
| -/* the components of the reply as we're constructing it. */
|
| -struct server_request {
|
| - /* Pointers to the next and previous entries on the list of replies */
|
| - /* that we're waiting to write. Only set if we have tried to respond */
|
| - /* and gotten EAGAIN. */
|
| - struct server_request *next_pending;
|
| - struct server_request *prev_pending;
|
| -
|
| - u16 trans_id; /* Transaction id. */
|
| - struct evdns_server_port *port; /* Which port received this request on? */
|
| - struct sockaddr_storage addr; /* Where to send the response */
|
| - socklen_t addrlen; /* length of addr */
|
| -
|
| - int n_answer; /* how many answer RRs have been set? */
|
| - int n_authority; /* how many authority RRs have been set? */
|
| - int n_additional; /* how many additional RRs have been set? */
|
| -
|
| - struct server_reply_item *answer; /* linked list of answer RRs */
|
| - struct server_reply_item *authority; /* linked list of authority RRs */
|
| - struct server_reply_item *additional; /* linked list of additional RRs */
|
| -
|
| - /* Constructed response. Only set once we're ready to send a reply. */
|
| - /* Once this is set, the RR fields are cleared, and no more should be set. */
|
| - char *response;
|
| - size_t response_len;
|
| -
|
| - /* Caller-visible fields: flags, questions. */
|
| - struct evdns_server_request base;
|
| -};
|
| -
|
| -/* helper macro */
|
| -#define OFFSET_OF(st, member) ((off_t) (((char*)&((st*)0)->member)-(char*)0))
|
| -
|
| -/* Given a pointer to an evdns_server_request, get the corresponding */
|
| -/* server_request. */
|
| -#define TO_SERVER_REQUEST(base_ptr) \
|
| - ((struct server_request*) \
|
| - (((char*)(base_ptr) - OFFSET_OF(struct server_request, base))))
|
| -
|
| -/* The number of good nameservers that we have */
|
| -static int global_good_nameservers = 0;
|
| -
|
| -/* inflight requests are contained in the req_head list */
|
| -/* and are actually going out across the network */
|
| -static int global_requests_inflight = 0;
|
| -/* requests which aren't inflight are in the waiting list */
|
| -/* and are counted here */
|
| -static int global_requests_waiting = 0;
|
| -
|
| -static int global_max_requests_inflight = 64;
|
| -
|
| -static struct timeval global_timeout = {5, 0}; /* 5 seconds */
|
| -static int global_max_reissues = 1; /* a reissue occurs when we get some errors from the server */
|
| -static int global_max_retransmits = 3; /* number of times we'll retransmit a request which timed out */
|
| -/* number of timeouts in a row before we consider this server to be down */
|
| -static int global_max_nameserver_timeout = 3;
|
| -
|
| -/* These are the timeout values for nameservers. If we find a nameserver is down */
|
| -/* we try to probe it at intervals as given below. Values are in seconds. */
|
| -static const struct timeval global_nameserver_timeouts[] = {{10, 0}, {60, 0}, {300, 0}, {900, 0}, {3600, 0}};
|
| -static const int global_nameserver_timeouts_length = sizeof(global_nameserver_timeouts)/sizeof(struct timeval);
|
| -
|
| -static struct nameserver *nameserver_pick(void);
|
| -static void evdns_request_insert(struct request *req, struct request **head);
|
| -static void nameserver_ready_callback(int fd, short events, void *arg);
|
| -static int evdns_transmit(void);
|
| -static int evdns_request_transmit(struct request *req);
|
| -static void nameserver_send_probe(struct nameserver *const ns);
|
| -static void search_request_finished(struct request *const);
|
| -static int search_try_next(struct request *const req);
|
| -static int search_request_new(int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg);
|
| -static void evdns_requests_pump_waiting_queue(void);
|
| -static u16 transaction_id_pick(void);
|
| -static struct request *request_new(int type, const char *name, int flags, evdns_callback_type callback, void *ptr);
|
| -static void request_submit(struct request *const req);
|
| -
|
| -static int server_request_free(struct server_request *req);
|
| -static void server_request_free_answers(struct server_request *req);
|
| -static void server_port_free(struct evdns_server_port *port);
|
| -static void server_port_ready_callback(int fd, short events, void *arg);
|
| -
|
| -static int strtoint(const char *const str);
|
| -
|
| -#ifdef WIN32
|
| -static int
|
| -last_error(int sock)
|
| -{
|
| - int optval, optvallen=sizeof(optval);
|
| - int err = WSAGetLastError();
|
| - if (err == WSAEWOULDBLOCK && sock >= 0) {
|
| - if (getsockopt(sock, SOL_SOCKET, SO_ERROR, (void*)&optval,
|
| - &optvallen))
|
| - return err;
|
| - if (optval)
|
| - return optval;
|
| - }
|
| - return err;
|
| -
|
| -}
|
| -static int
|
| -error_is_eagain(int err)
|
| -{
|
| - return err == EAGAIN || err == WSAEWOULDBLOCK;
|
| -}
|
| -static int
|
| -inet_aton(const char *c, struct in_addr *addr)
|
| -{
|
| - ev_uint32_t r;
|
| - if (strcmp(c, "255.255.255.255") == 0) {
|
| - addr->s_addr = 0xffffffffu;
|
| - } else {
|
| - r = inet_addr(c);
|
| - if (r == INADDR_NONE)
|
| - return 0;
|
| - addr->s_addr = r;
|
| - }
|
| - return 1;
|
| -}
|
| -#else
|
| -#define last_error(sock) (errno)
|
| -#define error_is_eagain(err) ((err) == EAGAIN)
|
| -#endif
|
| -#define CLOSE_SOCKET(s) EVUTIL_CLOSESOCKET(s)
|
| -
|
| -#define ISSPACE(c) isspace((int)(unsigned char)(c))
|
| -#define ISDIGIT(c) isdigit((int)(unsigned char)(c))
|
| -
|
| -static const char *
|
| -debug_ntoa(u32 address)
|
| -{
|
| - static char buf[32];
|
| - u32 a = ntohl(address);
|
| - evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d",
|
| - (int)(u8)((a>>24)&0xff),
|
| - (int)(u8)((a>>16)&0xff),
|
| - (int)(u8)((a>>8 )&0xff),
|
| - (int)(u8)((a )&0xff));
|
| - return buf;
|
| -}
|
| -
|
| -static evdns_debug_log_fn_type evdns_log_fn = NULL;
|
| -
|
| -void
|
| -evdns_set_log_fn(evdns_debug_log_fn_type fn)
|
| -{
|
| - evdns_log_fn = fn;
|
| -}
|
| -
|
| -#ifdef __GNUC__
|
| -#define EVDNS_LOG_CHECK __attribute__ ((format(printf, 2, 3)))
|
| -#else
|
| -#define EVDNS_LOG_CHECK
|
| -#endif
|
| -
|
| -static void _evdns_log(int warn, const char *fmt, ...) EVDNS_LOG_CHECK;
|
| -static void
|
| -_evdns_log(int warn, const char *fmt, ...)
|
| -{
|
| - va_list args;
|
| - static char buf[512];
|
| - if (!evdns_log_fn)
|
| - return;
|
| - va_start(args,fmt);
|
| - evutil_vsnprintf(buf, sizeof(buf), fmt, args);
|
| - buf[sizeof(buf)-1] = '\0';
|
| - evdns_log_fn(warn, buf);
|
| - va_end(args);
|
| -}
|
| -
|
| -#define log _evdns_log
|
| -
|
| -/* This walks the list of inflight requests to find the */
|
| -/* one with a matching transaction id. Returns NULL on */
|
| -/* failure */
|
| -static struct request *
|
| -request_find_from_trans_id(u16 trans_id) {
|
| - struct request *req = req_head, *const started_at = req_head;
|
| -
|
| - if (req) {
|
| - do {
|
| - if (req->trans_id == trans_id) return req;
|
| - req = req->next;
|
| - } while (req != started_at);
|
| - }
|
| -
|
| - return NULL;
|
| -}
|
| -
|
| -/* a libevent callback function which is called when a nameserver */
|
| -/* has gone down and we want to test if it has came back to life yet */
|
| -static void
|
| -nameserver_prod_callback(int fd, short events, void *arg) {
|
| - struct nameserver *const ns = (struct nameserver *) arg;
|
| - (void)fd;
|
| - (void)events;
|
| -
|
| - nameserver_send_probe(ns);
|
| -}
|
| -
|
| -/* a libevent callback which is called when a nameserver probe (to see if */
|
| -/* it has come back to life) times out. We increment the count of failed_times */
|
| -/* and wait longer to send the next probe packet. */
|
| -static void
|
| -nameserver_probe_failed(struct nameserver *const ns) {
|
| - const struct timeval * timeout;
|
| - (void) evtimer_del(&ns->timeout_event);
|
| - if (ns->state == 1) {
|
| - /* This can happen if the nameserver acts in a way which makes us mark */
|
| - /* it as bad and then starts sending good replies. */
|
| - return;
|
| - }
|
| -
|
| - timeout =
|
| - &global_nameserver_timeouts[MIN(ns->failed_times,
|
| - global_nameserver_timeouts_length - 1)];
|
| - ns->failed_times++;
|
| -
|
| - if (evtimer_add(&ns->timeout_event, (struct timeval *) timeout) < 0) {
|
| - log(EVDNS_LOG_WARN,
|
| - "Error from libevent when adding timer event for %s",
|
| - debug_ntoa(ns->address));
|
| - /* ???? Do more? */
|
| - }
|
| -}
|
| -
|
| -/* called when a nameserver has been deemed to have failed. For example, too */
|
| -/* many packets have timed out etc */
|
| -static void
|
| -nameserver_failed(struct nameserver *const ns, const char *msg) {
|
| - struct request *req, *started_at;
|
| - /* if this nameserver has already been marked as failed */
|
| - /* then don't do anything */
|
| - if (!ns->state) return;
|
| -
|
| - log(EVDNS_LOG_WARN, "Nameserver %s has failed: %s",
|
| - debug_ntoa(ns->address), msg);
|
| - global_good_nameservers--;
|
| - assert(global_good_nameservers >= 0);
|
| - if (global_good_nameservers == 0) {
|
| - log(EVDNS_LOG_WARN, "All nameservers have failed");
|
| - }
|
| -
|
| - ns->state = 0;
|
| - ns->failed_times = 1;
|
| -
|
| - if (evtimer_add(&ns->timeout_event, (struct timeval *) &global_nameserver_timeouts[0]) < 0) {
|
| - log(EVDNS_LOG_WARN,
|
| - "Error from libevent when adding timer event for %s",
|
| - debug_ntoa(ns->address));
|
| - /* ???? Do more? */
|
| - }
|
| -
|
| - /* walk the list of inflight requests to see if any can be reassigned to */
|
| - /* a different server. Requests in the waiting queue don't have a */
|
| - /* nameserver assigned yet */
|
| -
|
| - /* if we don't have *any* good nameservers then there's no point */
|
| - /* trying to reassign requests to one */
|
| - if (!global_good_nameservers) return;
|
| -
|
| - req = req_head;
|
| - started_at = req_head;
|
| - if (req) {
|
| - do {
|
| - if (req->tx_count == 0 && req->ns == ns) {
|
| - /* still waiting to go out, can be moved */
|
| - /* to another server */
|
| - req->ns = nameserver_pick();
|
| - }
|
| - req = req->next;
|
| - } while (req != started_at);
|
| - }
|
| -}
|
| -
|
| -static void
|
| -nameserver_up(struct nameserver *const ns) {
|
| - if (ns->state) return;
|
| - log(EVDNS_LOG_WARN, "Nameserver %s is back up",
|
| - debug_ntoa(ns->address));
|
| - evtimer_del(&ns->timeout_event);
|
| - ns->state = 1;
|
| - ns->failed_times = 0;
|
| - ns->timedout = 0;
|
| - global_good_nameservers++;
|
| -}
|
| -
|
| -static void
|
| -request_trans_id_set(struct request *const req, const u16 trans_id) {
|
| - req->trans_id = trans_id;
|
| - *((u16 *) req->request) = htons(trans_id);
|
| -}
|
| -
|
| -/* Called to remove a request from a list and dealloc it. */
|
| -/* head is a pointer to the head of the list it should be */
|
| -/* removed from or NULL if the request isn't in a list. */
|
| -static void
|
| -request_finished(struct request *const req, struct request **head) {
|
| - if (head) {
|
| - if (req->next == req) {
|
| - /* only item in the list */
|
| - *head = NULL;
|
| - } else {
|
| - req->next->prev = req->prev;
|
| - req->prev->next = req->next;
|
| - if (*head == req) *head = req->next;
|
| - }
|
| - }
|
| -
|
| - log(EVDNS_LOG_DEBUG, "Removing timeout for request %lx",
|
| - (unsigned long) req);
|
| - evtimer_del(&req->timeout_event);
|
| -
|
| - search_request_finished(req);
|
| - global_requests_inflight--;
|
| -
|
| - if (!req->request_appended) {
|
| - /* need to free the request data on it's own */
|
| - free(req->request);
|
| - } else {
|
| - /* the request data is appended onto the header */
|
| - /* so everything gets free()ed when we: */
|
| - }
|
| -
|
| - free(req);
|
| -
|
| - evdns_requests_pump_waiting_queue();
|
| -}
|
| -
|
| -/* This is called when a server returns a funny error code. */
|
| -/* We try the request again with another server. */
|
| -/* */
|
| -/* return: */
|
| -/* 0 ok */
|
| -/* 1 failed/reissue is pointless */
|
| -static int
|
| -request_reissue(struct request *req) {
|
| - const struct nameserver *const last_ns = req->ns;
|
| - /* the last nameserver should have been marked as failing */
|
| - /* by the caller of this function, therefore pick will try */
|
| - /* not to return it */
|
| - req->ns = nameserver_pick();
|
| - if (req->ns == last_ns) {
|
| - /* ... but pick did return it */
|
| - /* not a lot of point in trying again with the */
|
| - /* same server */
|
| - return 1;
|
| - }
|
| -
|
| - req->reissue_count++;
|
| - req->tx_count = 0;
|
| - req->transmit_me = 1;
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -/* this function looks for space on the inflight queue and promotes */
|
| -/* requests from the waiting queue if it can. */
|
| -static void
|
| -evdns_requests_pump_waiting_queue(void) {
|
| - while (global_requests_inflight < global_max_requests_inflight &&
|
| - global_requests_waiting) {
|
| - struct request *req;
|
| - /* move a request from the waiting queue to the inflight queue */
|
| - assert(req_waiting_head);
|
| - if (req_waiting_head->next == req_waiting_head) {
|
| - /* only one item in the queue */
|
| - req = req_waiting_head;
|
| - req_waiting_head = NULL;
|
| - } else {
|
| - req = req_waiting_head;
|
| - req->next->prev = req->prev;
|
| - req->prev->next = req->next;
|
| - req_waiting_head = req->next;
|
| - }
|
| -
|
| - global_requests_waiting--;
|
| - global_requests_inflight++;
|
| -
|
| - req->ns = nameserver_pick();
|
| - request_trans_id_set(req, transaction_id_pick());
|
| -
|
| - evdns_request_insert(req, &req_head);
|
| - evdns_request_transmit(req);
|
| - evdns_transmit();
|
| - }
|
| -}
|
| -
|
| -static void
|
| -reply_callback(struct request *const req, u32 ttl, u32 err, struct reply *reply) {
|
| - switch (req->request_type) {
|
| - case TYPE_A:
|
| - if (reply)
|
| - req->user_callback(DNS_ERR_NONE, DNS_IPv4_A,
|
| - reply->data.a.addrcount, ttl,
|
| - reply->data.a.addresses,
|
| - req->user_pointer);
|
| - else
|
| - req->user_callback(err, 0, 0, 0, NULL, req->user_pointer);
|
| - return;
|
| - case TYPE_PTR:
|
| - if (reply) {
|
| - char *name = reply->data.ptr.name;
|
| - req->user_callback(DNS_ERR_NONE, DNS_PTR, 1, ttl,
|
| - &name, req->user_pointer);
|
| - } else {
|
| - req->user_callback(err, 0, 0, 0, NULL,
|
| - req->user_pointer);
|
| - }
|
| - return;
|
| - case TYPE_AAAA:
|
| - if (reply)
|
| - req->user_callback(DNS_ERR_NONE, DNS_IPv6_AAAA,
|
| - reply->data.aaaa.addrcount, ttl,
|
| - reply->data.aaaa.addresses,
|
| - req->user_pointer);
|
| - else
|
| - req->user_callback(err, 0, 0, 0, NULL, req->user_pointer);
|
| - return;
|
| - }
|
| - assert(0);
|
| -}
|
| -
|
| -/* this processes a parsed reply packet */
|
| -static void
|
| -reply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply) {
|
| - int error;
|
| - static const int error_codes[] = {
|
| - DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST,
|
| - DNS_ERR_NOTIMPL, DNS_ERR_REFUSED
|
| - };
|
| -
|
| - if (flags & 0x020f || !reply || !reply->have_answer) {
|
| - /* there was an error */
|
| - if (flags & 0x0200) {
|
| - error = DNS_ERR_TRUNCATED;
|
| - } else {
|
| - u16 error_code = (flags & 0x000f) - 1;
|
| - if (error_code > 4) {
|
| - error = DNS_ERR_UNKNOWN;
|
| - } else {
|
| - error = error_codes[error_code];
|
| - }
|
| - }
|
| -
|
| - switch(error) {
|
| - case DNS_ERR_NOTIMPL:
|
| - case DNS_ERR_REFUSED:
|
| - /* we regard these errors as marking a bad nameserver */
|
| - if (req->reissue_count < global_max_reissues) {
|
| - char msg[64];
|
| - evutil_snprintf(msg, sizeof(msg),
|
| - "Bad response %d (%s)",
|
| - error, evdns_err_to_string(error));
|
| - nameserver_failed(req->ns, msg);
|
| - if (!request_reissue(req)) return;
|
| - }
|
| - break;
|
| - case DNS_ERR_SERVERFAILED:
|
| - /* rcode 2 (servfailed) sometimes means "we
|
| - * are broken" and sometimes (with some binds)
|
| - * means "that request was very confusing."
|
| - * Treat this as a timeout, not a failure.
|
| - */
|
| - log(EVDNS_LOG_DEBUG, "Got a SERVERFAILED from nameserver %s; "
|
| - "will allow the request to time out.",
|
| - debug_ntoa(req->ns->address));
|
| - break;
|
| - default:
|
| - /* we got a good reply from the nameserver */
|
| - nameserver_up(req->ns);
|
| - }
|
| -
|
| - if (req->search_state && req->request_type != TYPE_PTR) {
|
| - /* if we have a list of domains to search in,
|
| - * try the next one */
|
| - if (!search_try_next(req)) {
|
| - /* a new request was issued so this
|
| - * request is finished and */
|
| - /* the user callback will be made when
|
| - * that request (or a */
|
| - /* child of it) finishes. */
|
| - request_finished(req, &req_head);
|
| - return;
|
| - }
|
| - }
|
| -
|
| - /* all else failed. Pass the failure up */
|
| - reply_callback(req, 0, error, NULL);
|
| - request_finished(req, &req_head);
|
| - } else {
|
| - /* all ok, tell the user */
|
| - reply_callback(req, ttl, 0, reply);
|
| - nameserver_up(req->ns);
|
| - request_finished(req, &req_head);
|
| - }
|
| -}
|
| -
|
| -static int
|
| -name_parse(u8 *packet, int length, int *idx, char *name_out, int name_out_len) {
|
| - int name_end = -1;
|
| - int j = *idx;
|
| - int ptr_count = 0;
|
| -#define GET32(x) do { if (j + 4 > length) goto err; memcpy(&_t32, packet + j, 4); j += 4; x = ntohl(_t32); } while(0)
|
| -#define GET16(x) do { if (j + 2 > length) goto err; memcpy(&_t, packet + j, 2); j += 2; x = ntohs(_t); } while(0)
|
| -#define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while(0)
|
| -
|
| - char *cp = name_out;
|
| - const char *const end = name_out + name_out_len;
|
| -
|
| - /* Normally, names are a series of length prefixed strings terminated */
|
| - /* with a length of 0 (the lengths are u8's < 63). */
|
| - /* However, the length can start with a pair of 1 bits and that */
|
| - /* means that the next 14 bits are a pointer within the current */
|
| - /* packet. */
|
| -
|
| - for(;;) {
|
| - u8 label_len;
|
| - if (j >= length) return -1;
|
| - GET8(label_len);
|
| - if (!label_len) break;
|
| - if (label_len & 0xc0) {
|
| - u8 ptr_low;
|
| - GET8(ptr_low);
|
| - if (name_end < 0) name_end = j;
|
| - j = (((int)label_len & 0x3f) << 8) + ptr_low;
|
| - /* Make sure that the target offset is in-bounds. */
|
| - if (j < 0 || j >= length) return -1;
|
| - /* If we've jumped more times than there are characters in the
|
| - * message, we must have a loop. */
|
| - if (++ptr_count > length) return -1;
|
| - continue;
|
| - }
|
| - if (label_len > 63) return -1;
|
| - if (cp != name_out) {
|
| - if (cp + 1 >= end) return -1;
|
| - *cp++ = '.';
|
| - }
|
| - if (cp + label_len >= end) return -1;
|
| - memcpy(cp, packet + j, label_len);
|
| - cp += label_len;
|
| - j += label_len;
|
| - }
|
| - if (cp >= end) return -1;
|
| - *cp = '\0';
|
| - if (name_end < 0)
|
| - *idx = j;
|
| - else
|
| - *idx = name_end;
|
| - return 0;
|
| - err:
|
| - return -1;
|
| -}
|
| -
|
| -/* parses a raw request from a nameserver */
|
| -static int
|
| -reply_parse(u8 *packet, int length) {
|
| - int j = 0, k = 0; /* index into packet */
|
| - u16 _t; /* used by the macros */
|
| - u32 _t32; /* used by the macros */
|
| - char tmp_name[256], cmp_name[256]; /* used by the macros */
|
| -
|
| - u16 trans_id, questions, answers, authority, additional, datalength;
|
| - u16 flags = 0;
|
| - u32 ttl, ttl_r = 0xffffffff;
|
| - struct reply reply;
|
| - struct request *req = NULL;
|
| - unsigned int i;
|
| -
|
| - GET16(trans_id);
|
| - GET16(flags);
|
| - GET16(questions);
|
| - GET16(answers);
|
| - GET16(authority);
|
| - GET16(additional);
|
| - (void) authority; /* suppress "unused variable" warnings. */
|
| - (void) additional; /* suppress "unused variable" warnings. */
|
| -
|
| - req = request_find_from_trans_id(trans_id);
|
| - if (!req) return -1;
|
| -
|
| - memset(&reply, 0, sizeof(reply));
|
| -
|
| - /* If it's not an answer, it doesn't correspond to any request. */
|
| - if (!(flags & 0x8000)) return -1; /* must be an answer */
|
| - if (flags & 0x020f) {
|
| - /* there was an error */
|
| - goto err;
|
| - }
|
| - /* if (!answers) return; */ /* must have an answer of some form */
|
| -
|
| - /* This macro skips a name in the DNS reply. */
|
| -#define SKIP_NAME \
|
| - do { tmp_name[0] = '\0'; \
|
| - if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
|
| - goto err; \
|
| - } while(0)
|
| -#define TEST_NAME \
|
| - do { tmp_name[0] = '\0'; \
|
| - cmp_name[0] = '\0'; \
|
| - k = j; \
|
| - if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
|
| - goto err; \
|
| - if (name_parse(req->request, req->request_len, &k, cmp_name, sizeof(cmp_name))<0) \
|
| - goto err; \
|
| - if (memcmp(tmp_name, cmp_name, strlen (tmp_name)) != 0) \
|
| - return (-1); /* we ignore mismatching names */ \
|
| - } while(0)
|
| -
|
| - reply.type = req->request_type;
|
| -
|
| - /* skip over each question in the reply */
|
| - for (i = 0; i < questions; ++i) {
|
| - /* the question looks like
|
| - * <label:name><u16:type><u16:class>
|
| - */
|
| - TEST_NAME;
|
| - j += 4;
|
| - if (j > length) goto err;
|
| - }
|
| -
|
| - /* now we have the answer section which looks like
|
| - * <label:name><u16:type><u16:class><u32:ttl><u16:len><data...>
|
| - */
|
| -
|
| - for (i = 0; i < answers; ++i) {
|
| - u16 type, class;
|
| -
|
| - SKIP_NAME;
|
| - GET16(type);
|
| - GET16(class);
|
| - GET32(ttl);
|
| - GET16(datalength);
|
| -
|
| - if (type == TYPE_A && class == CLASS_INET) {
|
| - int addrcount, addrtocopy;
|
| - if (req->request_type != TYPE_A) {
|
| - j += datalength; continue;
|
| - }
|
| - if ((datalength & 3) != 0) /* not an even number of As. */
|
| - goto err;
|
| - addrcount = datalength >> 2;
|
| - addrtocopy = MIN(MAX_ADDRS - reply.data.a.addrcount, (unsigned)addrcount);
|
| -
|
| - ttl_r = MIN(ttl_r, ttl);
|
| - /* we only bother with the first four addresses. */
|
| - if (j + 4*addrtocopy > length) goto err;
|
| - memcpy(&reply.data.a.addresses[reply.data.a.addrcount],
|
| - packet + j, 4*addrtocopy);
|
| - j += 4*addrtocopy;
|
| - reply.data.a.addrcount += addrtocopy;
|
| - reply.have_answer = 1;
|
| - if (reply.data.a.addrcount == MAX_ADDRS) break;
|
| - } else if (type == TYPE_PTR && class == CLASS_INET) {
|
| - if (req->request_type != TYPE_PTR) {
|
| - j += datalength; continue;
|
| - }
|
| - if (name_parse(packet, length, &j, reply.data.ptr.name,
|
| - sizeof(reply.data.ptr.name))<0)
|
| - goto err;
|
| - ttl_r = MIN(ttl_r, ttl);
|
| - reply.have_answer = 1;
|
| - break;
|
| - } else if (type == TYPE_AAAA && class == CLASS_INET) {
|
| - int addrcount, addrtocopy;
|
| - if (req->request_type != TYPE_AAAA) {
|
| - j += datalength; continue;
|
| - }
|
| - if ((datalength & 15) != 0) /* not an even number of AAAAs. */
|
| - goto err;
|
| - addrcount = datalength >> 4; /* each address is 16 bytes long */
|
| - addrtocopy = MIN(MAX_ADDRS - reply.data.aaaa.addrcount, (unsigned)addrcount);
|
| - ttl_r = MIN(ttl_r, ttl);
|
| -
|
| - /* we only bother with the first four addresses. */
|
| - if (j + 16*addrtocopy > length) goto err;
|
| - memcpy(&reply.data.aaaa.addresses[reply.data.aaaa.addrcount],
|
| - packet + j, 16*addrtocopy);
|
| - reply.data.aaaa.addrcount += addrtocopy;
|
| - j += 16*addrtocopy;
|
| - reply.have_answer = 1;
|
| - if (reply.data.aaaa.addrcount == MAX_ADDRS) break;
|
| - } else {
|
| - /* skip over any other type of resource */
|
| - j += datalength;
|
| - }
|
| - }
|
| -
|
| - reply_handle(req, flags, ttl_r, &reply);
|
| - return 0;
|
| - err:
|
| - if (req)
|
| - reply_handle(req, flags, 0, NULL);
|
| - return -1;
|
| -}
|
| -
|
| -/* Parse a raw request (packet,length) sent to a nameserver port (port) from */
|
| -/* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */
|
| -/* callback. */
|
| -static int
|
| -request_parse(u8 *packet, int length, struct evdns_server_port *port, struct sockaddr *addr, socklen_t addrlen)
|
| -{
|
| - int j = 0; /* index into packet */
|
| - u16 _t; /* used by the macros */
|
| - char tmp_name[256]; /* used by the macros */
|
| -
|
| - int i;
|
| - u16 trans_id, flags, questions, answers, authority, additional;
|
| - struct server_request *server_req = NULL;
|
| -
|
| - /* Get the header fields */
|
| - GET16(trans_id);
|
| - GET16(flags);
|
| - GET16(questions);
|
| - GET16(answers);
|
| - GET16(authority);
|
| - GET16(additional);
|
| -
|
| - if (flags & 0x8000) return -1; /* Must not be an answer. */
|
| - flags &= 0x0110; /* Only RD and CD get preserved. */
|
| -
|
| - server_req = malloc(sizeof(struct server_request));
|
| - if (server_req == NULL) return -1;
|
| - memset(server_req, 0, sizeof(struct server_request));
|
| -
|
| - server_req->trans_id = trans_id;
|
| - memcpy(&server_req->addr, addr, addrlen);
|
| - server_req->addrlen = addrlen;
|
| -
|
| - server_req->base.flags = flags;
|
| - server_req->base.nquestions = 0;
|
| - server_req->base.questions = malloc(sizeof(struct evdns_server_question *) * questions);
|
| - if (server_req->base.questions == NULL)
|
| - goto err;
|
| -
|
| - for (i = 0; i < questions; ++i) {
|
| - u16 type, class;
|
| - struct evdns_server_question *q;
|
| - int namelen;
|
| - if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)
|
| - goto err;
|
| - GET16(type);
|
| - GET16(class);
|
| - namelen = strlen(tmp_name);
|
| - q = malloc(sizeof(struct evdns_server_question) + namelen);
|
| - if (!q)
|
| - goto err;
|
| - q->type = type;
|
| - q->dns_question_class = class;
|
| - memcpy(q->name, tmp_name, namelen+1);
|
| - server_req->base.questions[server_req->base.nquestions++] = q;
|
| - }
|
| -
|
| - /* Ignore answers, authority, and additional. */
|
| -
|
| - server_req->port = port;
|
| - port->refcnt++;
|
| -
|
| - /* Only standard queries are supported. */
|
| - if (flags & 0x7800) {
|
| - evdns_server_request_respond(&(server_req->base), DNS_ERR_NOTIMPL);
|
| - return -1;
|
| - }
|
| -
|
| - port->user_callback(&(server_req->base), port->user_data);
|
| -
|
| - return 0;
|
| -err:
|
| - if (server_req) {
|
| - if (server_req->base.questions) {
|
| - for (i = 0; i < server_req->base.nquestions; ++i)
|
| - free(server_req->base.questions[i]);
|
| - free(server_req->base.questions);
|
| - }
|
| - free(server_req);
|
| - }
|
| - return -1;
|
| -
|
| -#undef SKIP_NAME
|
| -#undef GET32
|
| -#undef GET16
|
| -#undef GET8
|
| -}
|
| -
|
| -static u16
|
| -default_transaction_id_fn(void)
|
| -{
|
| - u16 trans_id;
|
| -#ifdef DNS_USE_CPU_CLOCK_FOR_ID
|
| - struct timespec ts;
|
| - static int clkid = -1;
|
| - if (clkid == -1) {
|
| - clkid = CLOCK_REALTIME;
|
| -#ifdef CLOCK_MONOTONIC
|
| - if (clock_gettime(CLOCK_MONOTONIC, &ts) != -1)
|
| - clkid = CLOCK_MONOTONIC;
|
| -#endif
|
| - }
|
| - if (clock_gettime(clkid, &ts) == -1)
|
| - event_err(1, "clock_gettime");
|
| - trans_id = ts.tv_nsec & 0xffff;
|
| -#endif
|
| -
|
| -#ifdef DNS_USE_FTIME_FOR_ID
|
| - struct _timeb tb;
|
| - _ftime(&tb);
|
| - trans_id = tb.millitm & 0xffff;
|
| -#endif
|
| -
|
| -#ifdef DNS_USE_GETTIMEOFDAY_FOR_ID
|
| - struct timeval tv;
|
| - evutil_gettimeofday(&tv, NULL);
|
| - trans_id = tv.tv_usec & 0xffff;
|
| -#endif
|
| -
|
| -#ifdef DNS_USE_OPENSSL_FOR_ID
|
| - if (RAND_pseudo_bytes((u8 *) &trans_id, 2) == -1) {
|
| - /* in the case that the RAND call fails we back */
|
| - /* down to using gettimeofday. */
|
| - /*
|
| - struct timeval tv;
|
| - evutil_gettimeofday(&tv, NULL);
|
| - trans_id = tv.tv_usec & 0xffff;
|
| - */
|
| - abort();
|
| - }
|
| -#endif
|
| - return trans_id;
|
| -}
|
| -
|
| -static ev_uint16_t (*trans_id_function)(void) = default_transaction_id_fn;
|
| -
|
| -void
|
| -evdns_set_transaction_id_fn(ev_uint16_t (*fn)(void))
|
| -{
|
| - if (fn)
|
| - trans_id_function = fn;
|
| - else
|
| - trans_id_function = default_transaction_id_fn;
|
| -}
|
| -
|
| -/* Try to choose a strong transaction id which isn't already in flight */
|
| -static u16
|
| -transaction_id_pick(void) {
|
| - for (;;) {
|
| - u16 trans_id = trans_id_function();
|
| -
|
| - if (trans_id == 0xffff) continue;
|
| -
|
| - if (request_find_from_trans_id(trans_id) == NULL)
|
| - return trans_id;
|
| - }
|
| -}
|
| -
|
| -/* choose a namesever to use. This function will try to ignore */
|
| -/* nameservers which we think are down and load balance across the rest */
|
| -/* by updating the server_head global each time. */
|
| -static struct nameserver *
|
| -nameserver_pick(void) {
|
| - struct nameserver *started_at = server_head, *picked;
|
| - if (!server_head) return NULL;
|
| -
|
| - /* if we don't have any good nameservers then there's no */
|
| - /* point in trying to find one. */
|
| - if (!global_good_nameservers) {
|
| - server_head = server_head->next;
|
| - return server_head;
|
| - }
|
| -
|
| - /* remember that nameservers are in a circular list */
|
| - for (;;) {
|
| - if (server_head->state) {
|
| - /* we think this server is currently good */
|
| - picked = server_head;
|
| - server_head = server_head->next;
|
| - return picked;
|
| - }
|
| -
|
| - server_head = server_head->next;
|
| - if (server_head == started_at) {
|
| - /* all the nameservers seem to be down */
|
| - /* so we just return this one and hope for the */
|
| - /* best */
|
| - assert(global_good_nameservers == 0);
|
| - picked = server_head;
|
| - server_head = server_head->next;
|
| - return picked;
|
| - }
|
| - }
|
| -}
|
| -
|
| -static int
|
| -address_is_correct(struct nameserver *ns, struct sockaddr *sa, socklen_t slen)
|
| -{
|
| - struct sockaddr_in *sin = (struct sockaddr_in*) sa;
|
| - if (sa->sa_family != AF_INET || slen != sizeof(struct sockaddr_in))
|
| - return 0;
|
| - if (sin->sin_addr.s_addr != ns->address)
|
| - return 0;
|
| - return 1;
|
| -}
|
| -
|
| -/* this is called when a namesever socket is ready for reading */
|
| -static void
|
| -nameserver_read(struct nameserver *ns) {
|
| - u8 packet[1500];
|
| - struct sockaddr_storage ss;
|
| - socklen_t addrlen = sizeof(ss);
|
| -
|
| - for (;;) {
|
| - const int r = recvfrom(ns->socket, packet, sizeof(packet), 0,
|
| - (struct sockaddr*)&ss, &addrlen);
|
| - if (r < 0) {
|
| - int err = last_error(ns->socket);
|
| - if (error_is_eagain(err)) return;
|
| - nameserver_failed(ns, strerror(err));
|
| - return;
|
| - }
|
| - if (!address_is_correct(ns, (struct sockaddr*)&ss, addrlen)) {
|
| - log(EVDNS_LOG_WARN, "Address mismatch on received "
|
| - "DNS packet.");
|
| - return;
|
| - }
|
| - ns->timedout = 0;
|
| - reply_parse(packet, r);
|
| - }
|
| -}
|
| -
|
| -/* Read a packet from a DNS client on a server port s, parse it, and */
|
| -/* act accordingly. */
|
| -static void
|
| -server_port_read(struct evdns_server_port *s) {
|
| - u8 packet[1500];
|
| - struct sockaddr_storage addr;
|
| - socklen_t addrlen;
|
| - int r;
|
| -
|
| - for (;;) {
|
| - addrlen = sizeof(struct sockaddr_storage);
|
| - r = recvfrom(s->socket, packet, sizeof(packet), 0,
|
| - (struct sockaddr*) &addr, &addrlen);
|
| - if (r < 0) {
|
| - int err = last_error(s->socket);
|
| - if (error_is_eagain(err)) return;
|
| - log(EVDNS_LOG_WARN, "Error %s (%d) while reading request.",
|
| - strerror(err), err);
|
| - return;
|
| - }
|
| - request_parse(packet, r, s, (struct sockaddr*) &addr, addrlen);
|
| - }
|
| -}
|
| -
|
| -/* Try to write all pending replies on a given DNS server port. */
|
| -static void
|
| -server_port_flush(struct evdns_server_port *port)
|
| -{
|
| - while (port->pending_replies) {
|
| - struct server_request *req = port->pending_replies;
|
| - int r = sendto(port->socket, req->response, req->response_len, 0,
|
| - (struct sockaddr*) &req->addr, req->addrlen);
|
| - if (r < 0) {
|
| - int err = last_error(port->socket);
|
| - if (error_is_eagain(err))
|
| - return;
|
| - log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", strerror(err), err);
|
| - }
|
| - if (server_request_free(req)) {
|
| - /* we released the last reference to req->port. */
|
| - return;
|
| - }
|
| - }
|
| -
|
| - /* We have no more pending requests; stop listening for 'writeable' events. */
|
| - (void) event_del(&port->event);
|
| - event_set(&port->event, port->socket, EV_READ | EV_PERSIST,
|
| - server_port_ready_callback, port);
|
| - if (event_add(&port->event, NULL) < 0) {
|
| - log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server.");
|
| - /* ???? Do more? */
|
| - }
|
| -}
|
| -
|
| -/* set if we are waiting for the ability to write to this server. */
|
| -/* if waiting is true then we ask libevent for EV_WRITE events, otherwise */
|
| -/* we stop these events. */
|
| -static void
|
| -nameserver_write_waiting(struct nameserver *ns, char waiting) {
|
| - if (ns->write_waiting == waiting) return;
|
| -
|
| - ns->write_waiting = waiting;
|
| - (void) event_del(&ns->event);
|
| - event_set(&ns->event, ns->socket, EV_READ | (waiting ? EV_WRITE : 0) | EV_PERSIST,
|
| - nameserver_ready_callback, ns);
|
| - if (event_add(&ns->event, NULL) < 0) {
|
| - log(EVDNS_LOG_WARN, "Error from libevent when adding event for %s",
|
| - debug_ntoa(ns->address));
|
| - /* ???? Do more? */
|
| - }
|
| -}
|
| -
|
| -/* a callback function. Called by libevent when the kernel says that */
|
| -/* a nameserver socket is ready for writing or reading */
|
| -static void
|
| -nameserver_ready_callback(int fd, short events, void *arg) {
|
| - struct nameserver *ns = (struct nameserver *) arg;
|
| - (void)fd;
|
| -
|
| - if (events & EV_WRITE) {
|
| - ns->choked = 0;
|
| - if (!evdns_transmit()) {
|
| - nameserver_write_waiting(ns, 0);
|
| - }
|
| - }
|
| - if (events & EV_READ) {
|
| - nameserver_read(ns);
|
| - }
|
| -}
|
| -
|
| -/* a callback function. Called by libevent when the kernel says that */
|
| -/* a server socket is ready for writing or reading. */
|
| -static void
|
| -server_port_ready_callback(int fd, short events, void *arg) {
|
| - struct evdns_server_port *port = (struct evdns_server_port *) arg;
|
| - (void) fd;
|
| -
|
| - if (events & EV_WRITE) {
|
| - port->choked = 0;
|
| - server_port_flush(port);
|
| - }
|
| - if (events & EV_READ) {
|
| - server_port_read(port);
|
| - }
|
| -}
|
| -
|
| -/* This is an inefficient representation; only use it via the dnslabel_table_*
|
| - * functions, so that is can be safely replaced with something smarter later. */
|
| -#define MAX_LABELS 128
|
| -/* Structures used to implement name compression */
|
| -struct dnslabel_entry { char *v; off_t pos; };
|
| -struct dnslabel_table {
|
| - int n_labels; /* number of current entries */
|
| - /* map from name to position in message */
|
| - struct dnslabel_entry labels[MAX_LABELS];
|
| -};
|
| -
|
| -/* Initialize dnslabel_table. */
|
| -static void
|
| -dnslabel_table_init(struct dnslabel_table *table)
|
| -{
|
| - table->n_labels = 0;
|
| -}
|
| -
|
| -/* Free all storage held by table, but not the table itself. */
|
| -static void
|
| -dnslabel_clear(struct dnslabel_table *table)
|
| -{
|
| - int i;
|
| - for (i = 0; i < table->n_labels; ++i)
|
| - free(table->labels[i].v);
|
| - table->n_labels = 0;
|
| -}
|
| -
|
| -/* return the position of the label in the current message, or -1 if the label */
|
| -/* hasn't been used yet. */
|
| -static int
|
| -dnslabel_table_get_pos(const struct dnslabel_table *table, const char *label)
|
| -{
|
| - int i;
|
| - for (i = 0; i < table->n_labels; ++i) {
|
| - if (!strcmp(label, table->labels[i].v))
|
| - return table->labels[i].pos;
|
| - }
|
| - return -1;
|
| -}
|
| -
|
| -/* remember that we've used the label at position pos */
|
| -static int
|
| -dnslabel_table_add(struct dnslabel_table *table, const char *label, off_t pos)
|
| -{
|
| - char *v;
|
| - int p;
|
| - if (table->n_labels == MAX_LABELS)
|
| - return (-1);
|
| - v = strdup(label);
|
| - if (v == NULL)
|
| - return (-1);
|
| - p = table->n_labels++;
|
| - table->labels[p].v = v;
|
| - table->labels[p].pos = pos;
|
| -
|
| - return (0);
|
| -}
|
| -
|
| -/* Converts a string to a length-prefixed set of DNS labels, starting */
|
| -/* at buf[j]. name and buf must not overlap. name_len should be the length */
|
| -/* of name. table is optional, and is used for compression. */
|
| -/* */
|
| -/* Input: abc.def */
|
| -/* Output: <3>abc<3>def<0> */
|
| -/* */
|
| -/* Returns the first index after the encoded name, or negative on error. */
|
| -/* -1 label was > 63 bytes */
|
| -/* -2 name too long to fit in buffer. */
|
| -/* */
|
| -static off_t
|
| -dnsname_to_labels(u8 *const buf, size_t buf_len, off_t j,
|
| - const char *name, const int name_len,
|
| - struct dnslabel_table *table) {
|
| - const char *end = name + name_len;
|
| - int ref = 0;
|
| - u16 _t;
|
| -
|
| -#define APPEND16(x) do { \
|
| - if (j + 2 > (off_t)buf_len) \
|
| - goto overflow; \
|
| - _t = htons(x); \
|
| - memcpy(buf + j, &_t, 2); \
|
| - j += 2; \
|
| - } while (0)
|
| -#define APPEND32(x) do { \
|
| - if (j + 4 > (off_t)buf_len) \
|
| - goto overflow; \
|
| - _t32 = htonl(x); \
|
| - memcpy(buf + j, &_t32, 4); \
|
| - j += 4; \
|
| - } while (0)
|
| -
|
| - if (name_len > 255) return -2;
|
| -
|
| - for (;;) {
|
| - const char *const start = name;
|
| - if (table && (ref = dnslabel_table_get_pos(table, name)) >= 0) {
|
| - APPEND16(ref | 0xc000);
|
| - return j;
|
| - }
|
| - name = strchr(name, '.');
|
| - if (!name) {
|
| - const unsigned int label_len = end - start;
|
| - if (label_len > 63) return -1;
|
| - if ((size_t)(j+label_len+1) > buf_len) return -2;
|
| - if (table) dnslabel_table_add(table, start, j);
|
| - buf[j++] = label_len;
|
| -
|
| - memcpy(buf + j, start, end - start);
|
| - j += end - start;
|
| - break;
|
| - } else {
|
| - /* append length of the label. */
|
| - const unsigned int label_len = name - start;
|
| - if (label_len > 63) return -1;
|
| - if ((size_t)(j+label_len+1) > buf_len) return -2;
|
| - if (table) dnslabel_table_add(table, start, j);
|
| - buf[j++] = label_len;
|
| -
|
| - memcpy(buf + j, start, name - start);
|
| - j += name - start;
|
| - /* hop over the '.' */
|
| - name++;
|
| - }
|
| - }
|
| -
|
| - /* the labels must be terminated by a 0. */
|
| - /* It's possible that the name ended in a . */
|
| - /* in which case the zero is already there */
|
| - if (!j || buf[j-1]) buf[j++] = 0;
|
| - return j;
|
| - overflow:
|
| - return (-2);
|
| -}
|
| -
|
| -/* Finds the length of a dns request for a DNS name of the given */
|
| -/* length. The actual request may be smaller than the value returned */
|
| -/* here */
|
| -static int
|
| -evdns_request_len(const int name_len) {
|
| - return 96 + /* length of the DNS standard header */
|
| - name_len + 2 +
|
| - 4; /* space for the resource type */
|
| -}
|
| -
|
| -/* build a dns request packet into buf. buf should be at least as long */
|
| -/* as evdns_request_len told you it should be. */
|
| -/* */
|
| -/* Returns the amount of space used. Negative on error. */
|
| -static int
|
| -evdns_request_data_build(const char *const name, const int name_len,
|
| - const u16 trans_id, const u16 type, const u16 class,
|
| - u8 *const buf, size_t buf_len) {
|
| - off_t j = 0; /* current offset into buf */
|
| - u16 _t; /* used by the macros */
|
| -
|
| - APPEND16(trans_id);
|
| - APPEND16(0x0100); /* standard query, recusion needed */
|
| - APPEND16(1); /* one question */
|
| - APPEND16(0); /* no answers */
|
| - APPEND16(0); /* no authority */
|
| - APPEND16(0); /* no additional */
|
| -
|
| - j = dnsname_to_labels(buf, buf_len, j, name, name_len, NULL);
|
| - if (j < 0) {
|
| - return (int)j;
|
| - }
|
| -
|
| - APPEND16(type);
|
| - APPEND16(class);
|
| -
|
| - return (int)j;
|
| - overflow:
|
| - return (-1);
|
| -}
|
| -
|
| -/* exported function */
|
| -struct evdns_server_port *
|
| -evdns_add_server_port(int socket, int is_tcp, evdns_request_callback_fn_type cb, void *user_data)
|
| -{
|
| - struct evdns_server_port *port;
|
| - if (!(port = malloc(sizeof(struct evdns_server_port))))
|
| - return NULL;
|
| - memset(port, 0, sizeof(struct evdns_server_port));
|
| -
|
| - assert(!is_tcp); /* TCP sockets not yet implemented */
|
| - port->socket = socket;
|
| - port->refcnt = 1;
|
| - port->choked = 0;
|
| - port->closing = 0;
|
| - port->user_callback = cb;
|
| - port->user_data = user_data;
|
| - port->pending_replies = NULL;
|
| -
|
| - event_set(&port->event, port->socket, EV_READ | EV_PERSIST,
|
| - server_port_ready_callback, port);
|
| - event_add(&port->event, NULL); /* check return. */
|
| - return port;
|
| -}
|
| -
|
| -/* exported function */
|
| -void
|
| -evdns_close_server_port(struct evdns_server_port *port)
|
| -{
|
| - if (--port->refcnt == 0)
|
| - server_port_free(port);
|
| - port->closing = 1;
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_add_reply(struct evdns_server_request *_req, int section, const char *name, int type, int class, int ttl, int datalen, int is_name, const char *data)
|
| -{
|
| - struct server_request *req = TO_SERVER_REQUEST(_req);
|
| - struct server_reply_item **itemp, *item;
|
| - int *countp;
|
| -
|
| - if (req->response) /* have we already answered? */
|
| - return (-1);
|
| -
|
| - switch (section) {
|
| - case EVDNS_ANSWER_SECTION:
|
| - itemp = &req->answer;
|
| - countp = &req->n_answer;
|
| - break;
|
| - case EVDNS_AUTHORITY_SECTION:
|
| - itemp = &req->authority;
|
| - countp = &req->n_authority;
|
| - break;
|
| - case EVDNS_ADDITIONAL_SECTION:
|
| - itemp = &req->additional;
|
| - countp = &req->n_additional;
|
| - break;
|
| - default:
|
| - return (-1);
|
| - }
|
| - while (*itemp) {
|
| - itemp = &((*itemp)->next);
|
| - }
|
| - item = malloc(sizeof(struct server_reply_item));
|
| - if (!item)
|
| - return -1;
|
| - item->next = NULL;
|
| - if (!(item->name = strdup(name))) {
|
| - free(item);
|
| - return -1;
|
| - }
|
| - item->type = type;
|
| - item->dns_question_class = class;
|
| - item->ttl = ttl;
|
| - item->is_name = is_name != 0;
|
| - item->datalen = 0;
|
| - item->data = NULL;
|
| - if (data) {
|
| - if (item->is_name) {
|
| - if (!(item->data = strdup(data))) {
|
| - free(item->name);
|
| - free(item);
|
| - return -1;
|
| - }
|
| - item->datalen = (u16)-1;
|
| - } else {
|
| - if (!(item->data = malloc(datalen))) {
|
| - free(item->name);
|
| - free(item);
|
| - return -1;
|
| - }
|
| - item->datalen = datalen;
|
| - memcpy(item->data, data, datalen);
|
| - }
|
| - }
|
| -
|
| - *itemp = item;
|
| - ++(*countp);
|
| - return 0;
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl)
|
| -{
|
| - return evdns_server_request_add_reply(
|
| - req, EVDNS_ANSWER_SECTION, name, TYPE_A, CLASS_INET,
|
| - ttl, n*4, 0, addrs);
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl)
|
| -{
|
| - return evdns_server_request_add_reply(
|
| - req, EVDNS_ANSWER_SECTION, name, TYPE_AAAA, CLASS_INET,
|
| - ttl, n*16, 0, addrs);
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl)
|
| -{
|
| - u32 a;
|
| - char buf[32];
|
| - assert(in || inaddr_name);
|
| - assert(!(in && inaddr_name));
|
| - if (in) {
|
| - a = ntohl(in->s_addr);
|
| - evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
|
| - (int)(u8)((a )&0xff),
|
| - (int)(u8)((a>>8 )&0xff),
|
| - (int)(u8)((a>>16)&0xff),
|
| - (int)(u8)((a>>24)&0xff));
|
| - inaddr_name = buf;
|
| - }
|
| - return evdns_server_request_add_reply(
|
| - req, EVDNS_ANSWER_SECTION, inaddr_name, TYPE_PTR, CLASS_INET,
|
| - ttl, -1, 1, hostname);
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl)
|
| -{
|
| - return evdns_server_request_add_reply(
|
| - req, EVDNS_ANSWER_SECTION, name, TYPE_CNAME, CLASS_INET,
|
| - ttl, -1, 1, cname);
|
| -}
|
| -
|
| -
|
| -static int
|
| -evdns_server_request_format_response(struct server_request *req, int err)
|
| -{
|
| - unsigned char buf[1500];
|
| - size_t buf_len = sizeof(buf);
|
| - off_t j = 0, r;
|
| - u16 _t;
|
| - u32 _t32;
|
| - int i;
|
| - u16 flags;
|
| - struct dnslabel_table table;
|
| -
|
| - if (err < 0 || err > 15) return -1;
|
| -
|
| - /* Set response bit and error code; copy OPCODE and RD fields from
|
| - * question; copy RA and AA if set by caller. */
|
| - flags = req->base.flags;
|
| - flags |= (0x8000 | err);
|
| -
|
| - dnslabel_table_init(&table);
|
| - APPEND16(req->trans_id);
|
| - APPEND16(flags);
|
| - APPEND16(req->base.nquestions);
|
| - APPEND16(req->n_answer);
|
| - APPEND16(req->n_authority);
|
| - APPEND16(req->n_additional);
|
| -
|
| - /* Add questions. */
|
| - for (i=0; i < req->base.nquestions; ++i) {
|
| - const char *s = req->base.questions[i]->name;
|
| - j = dnsname_to_labels(buf, buf_len, j, s, strlen(s), &table);
|
| - if (j < 0) {
|
| - dnslabel_clear(&table);
|
| - return (int) j;
|
| - }
|
| - APPEND16(req->base.questions[i]->type);
|
| - APPEND16(req->base.questions[i]->dns_question_class);
|
| - }
|
| -
|
| - /* Add answer, authority, and additional sections. */
|
| - for (i=0; i<3; ++i) {
|
| - struct server_reply_item *item;
|
| - if (i==0)
|
| - item = req->answer;
|
| - else if (i==1)
|
| - item = req->authority;
|
| - else
|
| - item = req->additional;
|
| - while (item) {
|
| - r = dnsname_to_labels(buf, buf_len, j, item->name, strlen(item->name), &table);
|
| - if (r < 0)
|
| - goto overflow;
|
| - j = r;
|
| -
|
| - APPEND16(item->type);
|
| - APPEND16(item->dns_question_class);
|
| - APPEND32(item->ttl);
|
| - if (item->is_name) {
|
| - off_t len_idx = j, name_start;
|
| - j += 2;
|
| - name_start = j;
|
| - r = dnsname_to_labels(buf, buf_len, j, item->data, strlen(item->data), &table);
|
| - if (r < 0)
|
| - goto overflow;
|
| - j = r;
|
| - _t = htons( (short) (j-name_start) );
|
| - memcpy(buf+len_idx, &_t, 2);
|
| - } else {
|
| - APPEND16(item->datalen);
|
| - if (j+item->datalen > (off_t)buf_len)
|
| - goto overflow;
|
| - memcpy(buf+j, item->data, item->datalen);
|
| - j += item->datalen;
|
| - }
|
| - item = item->next;
|
| - }
|
| - }
|
| -
|
| - if (j > 512) {
|
| -overflow:
|
| - j = 512;
|
| - buf[2] |= 0x02; /* set the truncated bit. */
|
| - }
|
| -
|
| - req->response_len = j;
|
| -
|
| - if (!(req->response = malloc(req->response_len))) {
|
| - server_request_free_answers(req);
|
| - dnslabel_clear(&table);
|
| - return (-1);
|
| - }
|
| - memcpy(req->response, buf, req->response_len);
|
| - server_request_free_answers(req);
|
| - dnslabel_clear(&table);
|
| - return (0);
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_respond(struct evdns_server_request *_req, int err)
|
| -{
|
| - struct server_request *req = TO_SERVER_REQUEST(_req);
|
| - struct evdns_server_port *port = req->port;
|
| - int r;
|
| - if (!req->response) {
|
| - if ((r = evdns_server_request_format_response(req, err))<0)
|
| - return r;
|
| - }
|
| -
|
| - r = sendto(port->socket, req->response, req->response_len, 0,
|
| - (struct sockaddr*) &req->addr, req->addrlen);
|
| - if (r<0) {
|
| - int sock_err = last_error(port->socket);
|
| - if (! error_is_eagain(sock_err))
|
| - return -1;
|
| -
|
| - if (port->pending_replies) {
|
| - req->prev_pending = port->pending_replies->prev_pending;
|
| - req->next_pending = port->pending_replies;
|
| - req->prev_pending->next_pending =
|
| - req->next_pending->prev_pending = req;
|
| - } else {
|
| - req->prev_pending = req->next_pending = req;
|
| - port->pending_replies = req;
|
| - port->choked = 1;
|
| -
|
| - (void) event_del(&port->event);
|
| - event_set(&port->event, port->socket, (port->closing?0:EV_READ) | EV_WRITE | EV_PERSIST, server_port_ready_callback, port);
|
| -
|
| - if (event_add(&port->event, NULL) < 0) {
|
| - log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server");
|
| - }
|
| -
|
| - }
|
| -
|
| - return 1;
|
| - }
|
| - if (server_request_free(req))
|
| - return 0;
|
| -
|
| - if (port->pending_replies)
|
| - server_port_flush(port);
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -/* Free all storage held by RRs in req. */
|
| -static void
|
| -server_request_free_answers(struct server_request *req)
|
| -{
|
| - struct server_reply_item *victim, *next, **list;
|
| - int i;
|
| - for (i = 0; i < 3; ++i) {
|
| - if (i==0)
|
| - list = &req->answer;
|
| - else if (i==1)
|
| - list = &req->authority;
|
| - else
|
| - list = &req->additional;
|
| -
|
| - victim = *list;
|
| - while (victim) {
|
| - next = victim->next;
|
| - free(victim->name);
|
| - if (victim->data)
|
| - free(victim->data);
|
| - free(victim);
|
| - victim = next;
|
| - }
|
| - *list = NULL;
|
| - }
|
| -}
|
| -
|
| -/* Free all storage held by req, and remove links to it. */
|
| -/* return true iff we just wound up freeing the server_port. */
|
| -static int
|
| -server_request_free(struct server_request *req)
|
| -{
|
| - int i, rc=1;
|
| - if (req->base.questions) {
|
| - for (i = 0; i < req->base.nquestions; ++i)
|
| - free(req->base.questions[i]);
|
| - free(req->base.questions);
|
| - }
|
| -
|
| - if (req->port) {
|
| - if (req->port->pending_replies == req) {
|
| - if (req->next_pending)
|
| - req->port->pending_replies = req->next_pending;
|
| - else
|
| - req->port->pending_replies = NULL;
|
| - }
|
| - rc = --req->port->refcnt;
|
| - }
|
| -
|
| - if (req->response) {
|
| - free(req->response);
|
| - }
|
| -
|
| - server_request_free_answers(req);
|
| -
|
| - if (req->next_pending && req->next_pending != req) {
|
| - req->next_pending->prev_pending = req->prev_pending;
|
| - req->prev_pending->next_pending = req->next_pending;
|
| - }
|
| -
|
| - if (rc == 0) {
|
| - server_port_free(req->port);
|
| - free(req);
|
| - return (1);
|
| - }
|
| - free(req);
|
| - return (0);
|
| -}
|
| -
|
| -/* Free all storage held by an evdns_server_port. Only called when */
|
| -static void
|
| -server_port_free(struct evdns_server_port *port)
|
| -{
|
| - assert(port);
|
| - assert(!port->refcnt);
|
| - assert(!port->pending_replies);
|
| - if (port->socket > 0) {
|
| - CLOSE_SOCKET(port->socket);
|
| - port->socket = -1;
|
| - }
|
| - (void) event_del(&port->event);
|
| - /* XXXX actually free the port? -NM */
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_drop(struct evdns_server_request *_req)
|
| -{
|
| - struct server_request *req = TO_SERVER_REQUEST(_req);
|
| - server_request_free(req);
|
| - return 0;
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_server_request_get_requesting_addr(struct evdns_server_request *_req, struct sockaddr *sa, int addr_len)
|
| -{
|
| - struct server_request *req = TO_SERVER_REQUEST(_req);
|
| - if (addr_len < (int)req->addrlen)
|
| - return -1;
|
| - memcpy(sa, &(req->addr), req->addrlen);
|
| - return req->addrlen;
|
| -}
|
| -
|
| -#undef APPEND16
|
| -#undef APPEND32
|
| -
|
| -/* this is a libevent callback function which is called when a request */
|
| -/* has timed out. */
|
| -static void
|
| -evdns_request_timeout_callback(int fd, short events, void *arg) {
|
| - struct request *const req = (struct request *) arg;
|
| - (void) fd;
|
| - (void) events;
|
| -
|
| - log(EVDNS_LOG_DEBUG, "Request %lx timed out", (unsigned long) arg);
|
| -
|
| - req->ns->timedout++;
|
| - if (req->ns->timedout > global_max_nameserver_timeout) {
|
| - req->ns->timedout = 0;
|
| - nameserver_failed(req->ns, "request timed out.");
|
| - }
|
| -
|
| - (void) evtimer_del(&req->timeout_event);
|
| - if (req->tx_count >= global_max_retransmits) {
|
| - /* this request has failed */
|
| - reply_callback(req, 0, DNS_ERR_TIMEOUT, NULL);
|
| - request_finished(req, &req_head);
|
| - } else {
|
| - /* retransmit it */
|
| - evdns_request_transmit(req);
|
| - }
|
| -}
|
| -
|
| -/* try to send a request to a given server. */
|
| -/* */
|
| -/* return: */
|
| -/* 0 ok */
|
| -/* 1 temporary failure */
|
| -/* 2 other failure */
|
| -static int
|
| -evdns_request_transmit_to(struct request *req, struct nameserver *server) {
|
| - struct sockaddr_in sin;
|
| - int r;
|
| - memset(&sin, 0, sizeof(sin));
|
| - sin.sin_addr.s_addr = req->ns->address;
|
| - sin.sin_port = req->ns->port;
|
| - sin.sin_family = AF_INET;
|
| -
|
| - r = sendto(server->socket, req->request, req->request_len, 0,
|
| - (struct sockaddr*)&sin, sizeof(sin));
|
| - if (r < 0) {
|
| - int err = last_error(server->socket);
|
| - if (error_is_eagain(err)) return 1;
|
| - nameserver_failed(req->ns, strerror(err));
|
| - return 2;
|
| - } else if (r != (int)req->request_len) {
|
| - return 1; /* short write */
|
| - } else {
|
| - return 0;
|
| - }
|
| -}
|
| -
|
| -/* try to send a request, updating the fields of the request */
|
| -/* as needed */
|
| -/* */
|
| -/* return: */
|
| -/* 0 ok */
|
| -/* 1 failed */
|
| -static int
|
| -evdns_request_transmit(struct request *req) {
|
| - int retcode = 0, r;
|
| -
|
| - /* if we fail to send this packet then this flag marks it */
|
| - /* for evdns_transmit */
|
| - req->transmit_me = 1;
|
| - if (req->trans_id == 0xffff) abort();
|
| -
|
| - if (req->ns->choked) {
|
| - /* don't bother trying to write to a socket */
|
| - /* which we have had EAGAIN from */
|
| - return 1;
|
| - }
|
| -
|
| - r = evdns_request_transmit_to(req, req->ns);
|
| - switch (r) {
|
| - case 1:
|
| - /* temp failure */
|
| - req->ns->choked = 1;
|
| - nameserver_write_waiting(req->ns, 1);
|
| - return 1;
|
| - case 2:
|
| - /* failed in some other way */
|
| - retcode = 1;
|
| - /* fall through */
|
| - default:
|
| - /* all ok */
|
| - log(EVDNS_LOG_DEBUG,
|
| - "Setting timeout for request %lx", (unsigned long) req);
|
| - if (evtimer_add(&req->timeout_event, &global_timeout) < 0) {
|
| - log(EVDNS_LOG_WARN,
|
| - "Error from libevent when adding timer for request %lx",
|
| - (unsigned long) req);
|
| - /* ???? Do more? */
|
| - }
|
| - req->tx_count++;
|
| - req->transmit_me = 0;
|
| - return retcode;
|
| - }
|
| -}
|
| -
|
| -static void
|
| -nameserver_probe_callback(int result, char type, int count, int ttl, void *addresses, void *arg) {
|
| - struct nameserver *const ns = (struct nameserver *) arg;
|
| - (void) type;
|
| - (void) count;
|
| - (void) ttl;
|
| - (void) addresses;
|
| -
|
| - if (result == DNS_ERR_NONE || result == DNS_ERR_NOTEXIST) {
|
| - /* this is a good reply */
|
| - nameserver_up(ns);
|
| - } else nameserver_probe_failed(ns);
|
| -}
|
| -
|
| -static void
|
| -nameserver_send_probe(struct nameserver *const ns) {
|
| - struct request *req;
|
| - /* here we need to send a probe to a given nameserver */
|
| - /* in the hope that it is up now. */
|
| -
|
| - log(EVDNS_LOG_DEBUG, "Sending probe to %s", debug_ntoa(ns->address));
|
| -
|
| - req = request_new(TYPE_A, "www.google.com", DNS_QUERY_NO_SEARCH, nameserver_probe_callback, ns);
|
| - if (!req) return;
|
| - /* we force this into the inflight queue no matter what */
|
| - request_trans_id_set(req, transaction_id_pick());
|
| - req->ns = ns;
|
| - request_submit(req);
|
| -}
|
| -
|
| -/* returns: */
|
| -/* 0 didn't try to transmit anything */
|
| -/* 1 tried to transmit something */
|
| -static int
|
| -evdns_transmit(void) {
|
| - char did_try_to_transmit = 0;
|
| -
|
| - if (req_head) {
|
| - struct request *const started_at = req_head, *req = req_head;
|
| - /* first transmit all the requests which are currently waiting */
|
| - do {
|
| - if (req->transmit_me) {
|
| - did_try_to_transmit = 1;
|
| - evdns_request_transmit(req);
|
| - }
|
| -
|
| - req = req->next;
|
| - } while (req != started_at);
|
| - }
|
| -
|
| - return did_try_to_transmit;
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_count_nameservers(void)
|
| -{
|
| - const struct nameserver *server = server_head;
|
| - int n = 0;
|
| - if (!server)
|
| - return 0;
|
| - do {
|
| - ++n;
|
| - server = server->next;
|
| - } while (server != server_head);
|
| - return n;
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_clear_nameservers_and_suspend(void)
|
| -{
|
| - struct nameserver *server = server_head, *started_at = server_head;
|
| - struct request *req = req_head, *req_started_at = req_head;
|
| -
|
| - if (!server)
|
| - return 0;
|
| - while (1) {
|
| - struct nameserver *next = server->next;
|
| - (void) event_del(&server->event);
|
| - if (evtimer_initialized(&server->timeout_event))
|
| - (void) evtimer_del(&server->timeout_event);
|
| - if (server->socket >= 0)
|
| - CLOSE_SOCKET(server->socket);
|
| - free(server);
|
| - if (next == started_at)
|
| - break;
|
| - server = next;
|
| - }
|
| - server_head = NULL;
|
| - global_good_nameservers = 0;
|
| -
|
| - while (req) {
|
| - struct request *next = req->next;
|
| - req->tx_count = req->reissue_count = 0;
|
| - req->ns = NULL;
|
| - /* ???? What to do about searches? */
|
| - (void) evtimer_del(&req->timeout_event);
|
| - req->trans_id = 0;
|
| - req->transmit_me = 0;
|
| -
|
| - global_requests_waiting++;
|
| - evdns_request_insert(req, &req_waiting_head);
|
| - /* We want to insert these suspended elements at the front of
|
| - * the waiting queue, since they were pending before any of
|
| - * the waiting entries were added. This is a circular list,
|
| - * so we can just shift the start back by one.*/
|
| - req_waiting_head = req_waiting_head->prev;
|
| -
|
| - if (next == req_started_at)
|
| - break;
|
| - req = next;
|
| - }
|
| - req_head = NULL;
|
| - global_requests_inflight = 0;
|
| -
|
| - return 0;
|
| -}
|
| -
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_resume(void)
|
| -{
|
| - evdns_requests_pump_waiting_queue();
|
| - return 0;
|
| -}
|
| -
|
| -static int
|
| -_evdns_nameserver_add_impl(unsigned long int address, int port) {
|
| - /* first check to see if we already have this nameserver */
|
| -
|
| - const struct nameserver *server = server_head, *const started_at = server_head;
|
| - struct nameserver *ns;
|
| - int err = 0;
|
| - if (server) {
|
| - do {
|
| - if (server->address == address) return 3;
|
| - server = server->next;
|
| - } while (server != started_at);
|
| - }
|
| -
|
| - ns = (struct nameserver *) malloc(sizeof(struct nameserver));
|
| - if (!ns) return -1;
|
| -
|
| - memset(ns, 0, sizeof(struct nameserver));
|
| -
|
| - evtimer_set(&ns->timeout_event, nameserver_prod_callback, ns);
|
| -
|
| - ns->socket = socket(PF_INET, SOCK_DGRAM, 0);
|
| - if (ns->socket < 0) { err = 1; goto out1; }
|
| - FD_CLOSEONEXEC(ns->socket);
|
| - evutil_make_socket_nonblocking(ns->socket);
|
| -
|
| - ns->address = address;
|
| - ns->port = htons(port);
|
| - ns->state = 1;
|
| - event_set(&ns->event, ns->socket, EV_READ | EV_PERSIST, nameserver_ready_callback, ns);
|
| - if (event_add(&ns->event, NULL) < 0) {
|
| - err = 2;
|
| - goto out2;
|
| - }
|
| -
|
| - log(EVDNS_LOG_DEBUG, "Added nameserver %s", debug_ntoa(address));
|
| -
|
| - /* insert this nameserver into the list of them */
|
| - if (!server_head) {
|
| - ns->next = ns->prev = ns;
|
| - server_head = ns;
|
| - } else {
|
| - ns->next = server_head->next;
|
| - ns->prev = server_head;
|
| - server_head->next = ns;
|
| - if (server_head->prev == server_head) {
|
| - server_head->prev = ns;
|
| - }
|
| - }
|
| -
|
| - global_good_nameservers++;
|
| -
|
| - return 0;
|
| -
|
| -out2:
|
| - CLOSE_SOCKET(ns->socket);
|
| -out1:
|
| - free(ns);
|
| - log(EVDNS_LOG_WARN, "Unable to add nameserver %s: error %d", debug_ntoa(address), err);
|
| - return err;
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_nameserver_add(unsigned long int address) {
|
| - return _evdns_nameserver_add_impl(address, 53);
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_nameserver_ip_add(const char *ip_as_string) {
|
| - struct in_addr ina;
|
| - int port;
|
| - char buf[20];
|
| - const char *cp;
|
| - cp = strchr(ip_as_string, ':');
|
| - if (! cp) {
|
| - cp = ip_as_string;
|
| - port = 53;
|
| - } else {
|
| - port = strtoint(cp+1);
|
| - if (port < 0 || port > 65535) {
|
| - return 4;
|
| - }
|
| - if ((cp-ip_as_string) >= (int)sizeof(buf)) {
|
| - return 4;
|
| - }
|
| - memcpy(buf, ip_as_string, cp-ip_as_string);
|
| - buf[cp-ip_as_string] = '\0';
|
| - cp = buf;
|
| - }
|
| - if (!inet_aton(cp, &ina)) {
|
| - return 4;
|
| - }
|
| - return _evdns_nameserver_add_impl(ina.s_addr, port);
|
| -}
|
| -
|
| -/* insert into the tail of the queue */
|
| -static void
|
| -evdns_request_insert(struct request *req, struct request **head) {
|
| - if (!*head) {
|
| - *head = req;
|
| - req->next = req->prev = req;
|
| - return;
|
| - }
|
| -
|
| - req->prev = (*head)->prev;
|
| - req->prev->next = req;
|
| - req->next = *head;
|
| - (*head)->prev = req;
|
| -}
|
| -
|
| -static int
|
| -string_num_dots(const char *s) {
|
| - int count = 0;
|
| - while ((s = strchr(s, '.'))) {
|
| - s++;
|
| - count++;
|
| - }
|
| - return count;
|
| -}
|
| -
|
| -static struct request *
|
| -request_new(int type, const char *name, int flags,
|
| - evdns_callback_type callback, void *user_ptr) {
|
| - const char issuing_now =
|
| - (global_requests_inflight < global_max_requests_inflight) ? 1 : 0;
|
| -
|
| - const int name_len = strlen(name);
|
| - const int request_max_len = evdns_request_len(name_len);
|
| - const u16 trans_id = issuing_now ? transaction_id_pick() : 0xffff;
|
| - /* the request data is alloced in a single block with the header */
|
| - struct request *const req =
|
| - (struct request *) malloc(sizeof(struct request) + request_max_len);
|
| - int rlen;
|
| - (void) flags;
|
| -
|
| - if (!req) return NULL;
|
| - memset(req, 0, sizeof(struct request));
|
| -
|
| - evtimer_set(&req->timeout_event, evdns_request_timeout_callback, req);
|
| -
|
| - /* request data lives just after the header */
|
| - req->request = ((u8 *) req) + sizeof(struct request);
|
| - /* denotes that the request data shouldn't be free()ed */
|
| - req->request_appended = 1;
|
| - rlen = evdns_request_data_build(name, name_len, trans_id,
|
| - type, CLASS_INET, req->request, request_max_len);
|
| - if (rlen < 0)
|
| - goto err1;
|
| - req->request_len = rlen;
|
| - req->trans_id = trans_id;
|
| - req->tx_count = 0;
|
| - req->request_type = type;
|
| - req->user_pointer = user_ptr;
|
| - req->user_callback = callback;
|
| - req->ns = issuing_now ? nameserver_pick() : NULL;
|
| - req->next = req->prev = NULL;
|
| -
|
| - return req;
|
| -err1:
|
| - free(req);
|
| - return NULL;
|
| -}
|
| -
|
| -static void
|
| -request_submit(struct request *const req) {
|
| - if (req->ns) {
|
| - /* if it has a nameserver assigned then this is going */
|
| - /* straight into the inflight queue */
|
| - evdns_request_insert(req, &req_head);
|
| - global_requests_inflight++;
|
| - evdns_request_transmit(req);
|
| - } else {
|
| - evdns_request_insert(req, &req_waiting_head);
|
| - global_requests_waiting++;
|
| - }
|
| -}
|
| -
|
| -/* exported function */
|
| -int evdns_resolve_ipv4(const char *name, int flags,
|
| - evdns_callback_type callback, void *ptr) {
|
| - log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
|
| - if (flags & DNS_QUERY_NO_SEARCH) {
|
| - struct request *const req =
|
| - request_new(TYPE_A, name, flags, callback, ptr);
|
| - if (req == NULL)
|
| - return (1);
|
| - request_submit(req);
|
| - return (0);
|
| - } else {
|
| - return (search_request_new(TYPE_A, name, flags, callback, ptr));
|
| - }
|
| -}
|
| -
|
| -/* exported function */
|
| -int evdns_resolve_ipv6(const char *name, int flags,
|
| - evdns_callback_type callback, void *ptr) {
|
| - log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
|
| - if (flags & DNS_QUERY_NO_SEARCH) {
|
| - struct request *const req =
|
| - request_new(TYPE_AAAA, name, flags, callback, ptr);
|
| - if (req == NULL)
|
| - return (1);
|
| - request_submit(req);
|
| - return (0);
|
| - } else {
|
| - return (search_request_new(TYPE_AAAA, name, flags, callback, ptr));
|
| - }
|
| -}
|
| -
|
| -int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
|
| - char buf[32];
|
| - struct request *req;
|
| - u32 a;
|
| - assert(in);
|
| - a = ntohl(in->s_addr);
|
| - evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
|
| - (int)(u8)((a )&0xff),
|
| - (int)(u8)((a>>8 )&0xff),
|
| - (int)(u8)((a>>16)&0xff),
|
| - (int)(u8)((a>>24)&0xff));
|
| - log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
|
| - req = request_new(TYPE_PTR, buf, flags, callback, ptr);
|
| - if (!req) return 1;
|
| - request_submit(req);
|
| - return 0;
|
| -}
|
| -
|
| -int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
|
| - /* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
|
| - char buf[73];
|
| - char *cp;
|
| - struct request *req;
|
| - int i;
|
| - assert(in);
|
| - cp = buf;
|
| - for (i=15; i >= 0; --i) {
|
| - u8 byte = in->s6_addr[i];
|
| - *cp++ = "0123456789abcdef"[byte & 0x0f];
|
| - *cp++ = '.';
|
| - *cp++ = "0123456789abcdef"[byte >> 4];
|
| - *cp++ = '.';
|
| - }
|
| - assert(cp + strlen("ip6.arpa") < buf+sizeof(buf));
|
| - memcpy(cp, "ip6.arpa", strlen("ip6.arpa")+1);
|
| - log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
|
| - req = request_new(TYPE_PTR, buf, flags, callback, ptr);
|
| - if (!req) return 1;
|
| - request_submit(req);
|
| - return 0;
|
| -}
|
| -
|
| -/*/////////////////////////////////////////////////////////////////// */
|
| -/* Search support */
|
| -/* */
|
| -/* the libc resolver has support for searching a number of domains */
|
| -/* to find a name. If nothing else then it takes the single domain */
|
| -/* from the gethostname() call. */
|
| -/* */
|
| -/* It can also be configured via the domain and search options in a */
|
| -/* resolv.conf. */
|
| -/* */
|
| -/* The ndots option controls how many dots it takes for the resolver */
|
| -/* to decide that a name is non-local and so try a raw lookup first. */
|
| -
|
| -struct search_domain {
|
| - int len;
|
| - struct search_domain *next;
|
| - /* the text string is appended to this structure */
|
| -};
|
| -
|
| -struct search_state {
|
| - int refcount;
|
| - int ndots;
|
| - int num_domains;
|
| - struct search_domain *head;
|
| -};
|
| -
|
| -static struct search_state *global_search_state = NULL;
|
| -
|
| -static void
|
| -search_state_decref(struct search_state *const state) {
|
| - if (!state) return;
|
| - state->refcount--;
|
| - if (!state->refcount) {
|
| - struct search_domain *next, *dom;
|
| - for (dom = state->head; dom; dom = next) {
|
| - next = dom->next;
|
| - free(dom);
|
| - }
|
| - free(state);
|
| - }
|
| -}
|
| -
|
| -static struct search_state *
|
| -search_state_new(void) {
|
| - struct search_state *state = (struct search_state *) malloc(sizeof(struct search_state));
|
| - if (!state) return NULL;
|
| - memset(state, 0, sizeof(struct search_state));
|
| - state->refcount = 1;
|
| - state->ndots = 1;
|
| -
|
| - return state;
|
| -}
|
| -
|
| -static void
|
| -search_postfix_clear(void) {
|
| - search_state_decref(global_search_state);
|
| -
|
| - global_search_state = search_state_new();
|
| -}
|
| -
|
| -/* exported function */
|
| -void
|
| -evdns_search_clear(void) {
|
| - search_postfix_clear();
|
| -}
|
| -
|
| -static void
|
| -search_postfix_add(const char *domain) {
|
| - int domain_len;
|
| - struct search_domain *sdomain;
|
| - while (domain[0] == '.') domain++;
|
| - domain_len = strlen(domain);
|
| -
|
| - if (!global_search_state) global_search_state = search_state_new();
|
| - if (!global_search_state) return;
|
| - global_search_state->num_domains++;
|
| -
|
| - sdomain = (struct search_domain *) malloc(sizeof(struct search_domain) + domain_len);
|
| - if (!sdomain) return;
|
| - memcpy( ((u8 *) sdomain) + sizeof(struct search_domain), domain, domain_len);
|
| - sdomain->next = global_search_state->head;
|
| - sdomain->len = domain_len;
|
| -
|
| - global_search_state->head = sdomain;
|
| -}
|
| -
|
| -/* reverse the order of members in the postfix list. This is needed because, */
|
| -/* when parsing resolv.conf we push elements in the wrong order */
|
| -static void
|
| -search_reverse(void) {
|
| - struct search_domain *cur, *prev = NULL, *next;
|
| - cur = global_search_state->head;
|
| - while (cur) {
|
| - next = cur->next;
|
| - cur->next = prev;
|
| - prev = cur;
|
| - cur = next;
|
| - }
|
| -
|
| - global_search_state->head = prev;
|
| -}
|
| -
|
| -/* exported function */
|
| -void
|
| -evdns_search_add(const char *domain) {
|
| - search_postfix_add(domain);
|
| -}
|
| -
|
| -/* exported function */
|
| -void
|
| -evdns_search_ndots_set(const int ndots) {
|
| - if (!global_search_state) global_search_state = search_state_new();
|
| - if (!global_search_state) return;
|
| - global_search_state->ndots = ndots;
|
| -}
|
| -
|
| -static void
|
| -search_set_from_hostname(void) {
|
| - char hostname[HOST_NAME_MAX + 1], *domainname;
|
| -
|
| - search_postfix_clear();
|
| - if (gethostname(hostname, sizeof(hostname))) return;
|
| - domainname = strchr(hostname, '.');
|
| - if (!domainname) return;
|
| - search_postfix_add(domainname);
|
| -}
|
| -
|
| -/* warning: returns malloced string */
|
| -static char *
|
| -search_make_new(const struct search_state *const state, int n, const char *const base_name) {
|
| - const int base_len = strlen(base_name);
|
| - const char need_to_append_dot = base_name[base_len - 1] == '.' ? 0 : 1;
|
| - struct search_domain *dom;
|
| -
|
| - for (dom = state->head; dom; dom = dom->next) {
|
| - if (!n--) {
|
| - /* this is the postfix we want */
|
| - /* the actual postfix string is kept at the end of the structure */
|
| - const u8 *const postfix = ((u8 *) dom) + sizeof(struct search_domain);
|
| - const int postfix_len = dom->len;
|
| - char *const newname = (char *) malloc(base_len + need_to_append_dot + postfix_len + 1);
|
| - if (!newname) return NULL;
|
| - memcpy(newname, base_name, base_len);
|
| - if (need_to_append_dot) newname[base_len] = '.';
|
| - memcpy(newname + base_len + need_to_append_dot, postfix, postfix_len);
|
| - newname[base_len + need_to_append_dot + postfix_len] = 0;
|
| - return newname;
|
| - }
|
| - }
|
| -
|
| - /* we ran off the end of the list and still didn't find the requested string */
|
| - abort();
|
| - return NULL; /* unreachable; stops warnings in some compilers. */
|
| -}
|
| -
|
| -static int
|
| -search_request_new(int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg) {
|
| - assert(type == TYPE_A || type == TYPE_AAAA);
|
| - if ( ((flags & DNS_QUERY_NO_SEARCH) == 0) &&
|
| - global_search_state &&
|
| - global_search_state->num_domains) {
|
| - /* we have some domains to search */
|
| - struct request *req;
|
| - if (string_num_dots(name) >= global_search_state->ndots) {
|
| - req = request_new(type, name, flags, user_callback, user_arg);
|
| - if (!req) return 1;
|
| - req->search_index = -1;
|
| - } else {
|
| - char *const new_name = search_make_new(global_search_state, 0, name);
|
| - if (!new_name) return 1;
|
| - req = request_new(type, new_name, flags, user_callback, user_arg);
|
| - free(new_name);
|
| - if (!req) return 1;
|
| - req->search_index = 0;
|
| - }
|
| - req->search_origname = strdup(name);
|
| - req->search_state = global_search_state;
|
| - req->search_flags = flags;
|
| - global_search_state->refcount++;
|
| - request_submit(req);
|
| - return 0;
|
| - } else {
|
| - struct request *const req = request_new(type, name, flags, user_callback, user_arg);
|
| - if (!req) return 1;
|
| - request_submit(req);
|
| - return 0;
|
| - }
|
| -}
|
| -
|
| -/* this is called when a request has failed to find a name. We need to check */
|
| -/* if it is part of a search and, if so, try the next name in the list */
|
| -/* returns: */
|
| -/* 0 another request has been submitted */
|
| -/* 1 no more requests needed */
|
| -static int
|
| -search_try_next(struct request *const req) {
|
| - if (req->search_state) {
|
| - /* it is part of a search */
|
| - char *new_name;
|
| - struct request *newreq;
|
| - req->search_index++;
|
| - if (req->search_index >= req->search_state->num_domains) {
|
| - /* no more postfixes to try, however we may need to try */
|
| - /* this name without a postfix */
|
| - if (string_num_dots(req->search_origname) < req->search_state->ndots) {
|
| - /* yep, we need to try it raw */
|
| - newreq = request_new(req->request_type, req->search_origname, req->search_flags, req->user_callback, req->user_pointer);
|
| - log(EVDNS_LOG_DEBUG, "Search: trying raw query %s", req->search_origname);
|
| - if (newreq) {
|
| - request_submit(newreq);
|
| - return 0;
|
| - }
|
| - }
|
| - return 1;
|
| - }
|
| -
|
| - new_name = search_make_new(req->search_state, req->search_index, req->search_origname);
|
| - if (!new_name) return 1;
|
| - log(EVDNS_LOG_DEBUG, "Search: now trying %s (%d)", new_name, req->search_index);
|
| - newreq = request_new(req->request_type, new_name, req->search_flags, req->user_callback, req->user_pointer);
|
| - free(new_name);
|
| - if (!newreq) return 1;
|
| - newreq->search_origname = req->search_origname;
|
| - req->search_origname = NULL;
|
| - newreq->search_state = req->search_state;
|
| - newreq->search_flags = req->search_flags;
|
| - newreq->search_index = req->search_index;
|
| - newreq->search_state->refcount++;
|
| - request_submit(newreq);
|
| - return 0;
|
| - }
|
| - return 1;
|
| -}
|
| -
|
| -static void
|
| -search_request_finished(struct request *const req) {
|
| - if (req->search_state) {
|
| - search_state_decref(req->search_state);
|
| - req->search_state = NULL;
|
| - }
|
| - if (req->search_origname) {
|
| - free(req->search_origname);
|
| - req->search_origname = NULL;
|
| - }
|
| -}
|
| -
|
| -/*/////////////////////////////////////////////////////////////////// */
|
| -/* Parsing resolv.conf files */
|
| -
|
| -static void
|
| -evdns_resolv_set_defaults(int flags) {
|
| - /* if the file isn't found then we assume a local resolver */
|
| - if (flags & DNS_OPTION_SEARCH) search_set_from_hostname();
|
| - if (flags & DNS_OPTION_NAMESERVERS) evdns_nameserver_ip_add("127.0.0.1");
|
| -}
|
| -
|
| -#ifndef HAVE_STRTOK_R
|
| -static char *
|
| -strtok_r(char *s, const char *delim, char **state) {
|
| - return strtok(s, delim);
|
| -}
|
| -#endif
|
| -
|
| -/* helper version of atoi which returns -1 on error */
|
| -static int
|
| -strtoint(const char *const str) {
|
| - char *endptr;
|
| - const int r = strtol(str, &endptr, 10);
|
| - if (*endptr) return -1;
|
| - return r;
|
| -}
|
| -
|
| -/* helper version of atoi that returns -1 on error and clips to bounds. */
|
| -static int
|
| -strtoint_clipped(const char *const str, int min, int max)
|
| -{
|
| - int r = strtoint(str);
|
| - if (r == -1)
|
| - return r;
|
| - else if (r<min)
|
| - return min;
|
| - else if (r>max)
|
| - return max;
|
| - else
|
| - return r;
|
| -}
|
| -
|
| -/* exported function */
|
| -int
|
| -evdns_set_option(const char *option, const char *val, int flags)
|
| -{
|
| - if (!strncmp(option, "ndots:", 6)) {
|
| - const int ndots = strtoint(val);
|
| - if (ndots == -1) return -1;
|
| - if (!(flags & DNS_OPTION_SEARCH)) return 0;
|
| - log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots);
|
| - if (!global_search_state) global_search_state = search_state_new();
|
| - if (!global_search_state) return -1;
|
| - global_search_state->ndots = ndots;
|
| - } else if (!strncmp(option, "timeout:", 8)) {
|
| - const int timeout = strtoint(val);
|
| - if (timeout == -1) return -1;
|
| - if (!(flags & DNS_OPTION_MISC)) return 0;
|
| - log(EVDNS_LOG_DEBUG, "Setting timeout to %d", timeout);
|
| - global_timeout.tv_sec = timeout;
|
| - } else if (!strncmp(option, "max-timeouts:", 12)) {
|
| - const int maxtimeout = strtoint_clipped(val, 1, 255);
|
| - if (maxtimeout == -1) return -1;
|
| - if (!(flags & DNS_OPTION_MISC)) return 0;
|
| - log(EVDNS_LOG_DEBUG, "Setting maximum allowed timeouts to %d",
|
| - maxtimeout);
|
| - global_max_nameserver_timeout = maxtimeout;
|
| - } else if (!strncmp(option, "max-inflight:", 13)) {
|
| - const int maxinflight = strtoint_clipped(val, 1, 65000);
|
| - if (maxinflight == -1) return -1;
|
| - if (!(flags & DNS_OPTION_MISC)) return 0;
|
| - log(EVDNS_LOG_DEBUG, "Setting maximum inflight requests to %d",
|
| - maxinflight);
|
| - global_max_requests_inflight = maxinflight;
|
| - } else if (!strncmp(option, "attempts:", 9)) {
|
| - int retries = strtoint(val);
|
| - if (retries == -1) return -1;
|
| - if (retries > 255) retries = 255;
|
| - if (!(flags & DNS_OPTION_MISC)) return 0;
|
| - log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries);
|
| - global_max_retransmits = retries;
|
| - }
|
| - return 0;
|
| -}
|
| -
|
| -static void
|
| -resolv_conf_parse_line(char *const start, int flags) {
|
| - char *strtok_state;
|
| - static const char *const delims = " \t";
|
| -#define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state)
|
| -
|
| - char *const first_token = strtok_r(start, delims, &strtok_state);
|
| - if (!first_token) return;
|
| -
|
| - if (!strcmp(first_token, "nameserver") && (flags & DNS_OPTION_NAMESERVERS)) {
|
| - const char *const nameserver = NEXT_TOKEN;
|
| - struct in_addr ina;
|
| -
|
| - if (nameserver && inet_aton(nameserver, &ina)) {
|
| - /* address is valid */
|
| - evdns_nameserver_add(ina.s_addr);
|
| - }
|
| - } else if (!strcmp(first_token, "domain") && (flags & DNS_OPTION_SEARCH)) {
|
| - const char *const domain = NEXT_TOKEN;
|
| - if (domain) {
|
| - search_postfix_clear();
|
| - search_postfix_add(domain);
|
| - }
|
| - } else if (!strcmp(first_token, "search") && (flags & DNS_OPTION_SEARCH)) {
|
| - const char *domain;
|
| - search_postfix_clear();
|
| -
|
| - while ((domain = NEXT_TOKEN)) {
|
| - search_postfix_add(domain);
|
| - }
|
| - search_reverse();
|
| - } else if (!strcmp(first_token, "options")) {
|
| - const char *option;
|
| - while ((option = NEXT_TOKEN)) {
|
| - const char *val = strchr(option, ':');
|
| - evdns_set_option(option, val ? val+1 : "", flags);
|
| - }
|
| - }
|
| -#undef NEXT_TOKEN
|
| -}
|
| -
|
| -/* exported function */
|
| -/* returns: */
|
| -/* 0 no errors */
|
| -/* 1 failed to open file */
|
| -/* 2 failed to stat file */
|
| -/* 3 file too large */
|
| -/* 4 out of memory */
|
| -/* 5 short read from file */
|
| -int
|
| -evdns_resolv_conf_parse(int flags, const char *const filename) {
|
| - struct stat st;
|
| - int fd, n, r;
|
| - u8 *resolv;
|
| - char *start;
|
| - int err = 0;
|
| -
|
| - log(EVDNS_LOG_DEBUG, "Parsing resolv.conf file %s", filename);
|
| -
|
| - fd = open(filename, O_RDONLY);
|
| - if (fd < 0) {
|
| - evdns_resolv_set_defaults(flags);
|
| - return 1;
|
| - }
|
| -
|
| - if (fstat(fd, &st)) { err = 2; goto out1; }
|
| - if (!st.st_size) {
|
| - evdns_resolv_set_defaults(flags);
|
| - err = (flags & DNS_OPTION_NAMESERVERS) ? 6 : 0;
|
| - goto out1;
|
| - }
|
| - if (st.st_size > 65535) { err = 3; goto out1; } /* no resolv.conf should be any bigger */
|
| -
|
| - resolv = (u8 *) malloc((size_t)st.st_size + 1);
|
| - if (!resolv) { err = 4; goto out1; }
|
| -
|
| - n = 0;
|
| - while ((r = read(fd, resolv+n, (size_t)st.st_size-n)) > 0) {
|
| - n += r;
|
| - if (n == st.st_size)
|
| - break;
|
| - assert(n < st.st_size);
|
| - }
|
| - if (r < 0) { err = 5; goto out2; }
|
| - resolv[n] = 0; /* we malloced an extra byte; this should be fine. */
|
| -
|
| - start = (char *) resolv;
|
| - for (;;) {
|
| - char *const newline = strchr(start, '\n');
|
| - if (!newline) {
|
| - resolv_conf_parse_line(start, flags);
|
| - break;
|
| - } else {
|
| - *newline = 0;
|
| - resolv_conf_parse_line(start, flags);
|
| - start = newline + 1;
|
| - }
|
| - }
|
| -
|
| - if (!server_head && (flags & DNS_OPTION_NAMESERVERS)) {
|
| - /* no nameservers were configured. */
|
| - evdns_nameserver_ip_add("127.0.0.1");
|
| - err = 6;
|
| - }
|
| - if (flags & DNS_OPTION_SEARCH && (!global_search_state || global_search_state->num_domains == 0)) {
|
| - search_set_from_hostname();
|
| - }
|
| -
|
| -out2:
|
| - free(resolv);
|
| -out1:
|
| - close(fd);
|
| - return err;
|
| -}
|
| -
|
| -#ifdef WIN32
|
| -/* Add multiple nameservers from a space-or-comma-separated list. */
|
| -static int
|
| -evdns_nameserver_ip_add_line(const char *ips) {
|
| - const char *addr;
|
| - char *buf;
|
| - int r;
|
| - while (*ips) {
|
| - while (ISSPACE(*ips) || *ips == ',' || *ips == '\t')
|
| - ++ips;
|
| - addr = ips;
|
| - while (ISDIGIT(*ips) || *ips == '.' || *ips == ':')
|
| - ++ips;
|
| - buf = malloc(ips-addr+1);
|
| - if (!buf) return 4;
|
| - memcpy(buf, addr, ips-addr);
|
| - buf[ips-addr] = '\0';
|
| - r = evdns_nameserver_ip_add(buf);
|
| - free(buf);
|
| - if (r) return r;
|
| - }
|
| - return 0;
|
| -}
|
| -
|
| -typedef DWORD(WINAPI *GetNetworkParams_fn_t)(FIXED_INFO *, DWORD*);
|
| -
|
| -/* Use the windows GetNetworkParams interface in iphlpapi.dll to */
|
| -/* figure out what our nameservers are. */
|
| -static int
|
| -load_nameservers_with_getnetworkparams(void)
|
| -{
|
| - /* Based on MSDN examples and inspection of c-ares code. */
|
| - FIXED_INFO *fixed;
|
| - HMODULE handle = 0;
|
| - ULONG size = sizeof(FIXED_INFO);
|
| - void *buf = NULL;
|
| - int status = 0, r, added_any;
|
| - IP_ADDR_STRING *ns;
|
| - GetNetworkParams_fn_t fn;
|
| -
|
| - if (!(handle = LoadLibraryA("iphlpapi.dll"))) {
|
| - log(EVDNS_LOG_WARN, "Could not open iphlpapi.dll");
|
| - status = -1;
|
| - goto done;
|
| - }
|
| - if (!(fn = (GetNetworkParams_fn_t) GetProcAddress(handle, "GetNetworkParams"))) {
|
| - log(EVDNS_LOG_WARN, "Could not get address of function.");
|
| - status = -1;
|
| - goto done;
|
| - }
|
| -
|
| - buf = malloc(size);
|
| - if (!buf) { status = 4; goto done; }
|
| - fixed = buf;
|
| - r = fn(fixed, &size);
|
| - if (r != ERROR_SUCCESS && r != ERROR_BUFFER_OVERFLOW) {
|
| - status = -1;
|
| - goto done;
|
| - }
|
| - if (r != ERROR_SUCCESS) {
|
| - free(buf);
|
| - buf = malloc(size);
|
| - if (!buf) { status = 4; goto done; }
|
| - fixed = buf;
|
| - r = fn(fixed, &size);
|
| - if (r != ERROR_SUCCESS) {
|
| - log(EVDNS_LOG_DEBUG, "fn() failed.");
|
| - status = -1;
|
| - goto done;
|
| - }
|
| - }
|
| -
|
| - assert(fixed);
|
| - added_any = 0;
|
| - ns = &(fixed->DnsServerList);
|
| - while (ns) {
|
| - r = evdns_nameserver_ip_add_line(ns->IpAddress.String);
|
| - if (r) {
|
| - log(EVDNS_LOG_DEBUG,"Could not add nameserver %s to list,error: %d",
|
| - (ns->IpAddress.String),(int)GetLastError());
|
| - status = r;
|
| - goto done;
|
| - } else {
|
| - log(EVDNS_LOG_DEBUG,"Succesfully added %s as nameserver",ns->IpAddress.String);
|
| - }
|
| -
|
| - added_any++;
|
| - ns = ns->Next;
|
| - }
|
| -
|
| - if (!added_any) {
|
| - log(EVDNS_LOG_DEBUG, "No nameservers added.");
|
| - status = -1;
|
| - }
|
| -
|
| - done:
|
| - if (buf)
|
| - free(buf);
|
| - if (handle)
|
| - FreeLibrary(handle);
|
| - return status;
|
| -}
|
| -
|
| -static int
|
| -config_nameserver_from_reg_key(HKEY key, const char *subkey)
|
| -{
|
| - char *buf;
|
| - DWORD bufsz = 0, type = 0;
|
| - int status = 0;
|
| -
|
| - if (RegQueryValueExA(key, subkey, 0, &type, NULL, &bufsz)
|
| - != ERROR_MORE_DATA)
|
| - return -1;
|
| - if (!(buf = malloc(bufsz)))
|
| - return -1;
|
| -
|
| - if (RegQueryValueExA(key, subkey, 0, &type, (LPBYTE)buf, &bufsz)
|
| - == ERROR_SUCCESS && bufsz > 1) {
|
| - status = evdns_nameserver_ip_add_line(buf);
|
| - }
|
| -
|
| - free(buf);
|
| - return status;
|
| -}
|
| -
|
| -#define SERVICES_KEY "System\\CurrentControlSet\\Services\\"
|
| -#define WIN_NS_9X_KEY SERVICES_KEY "VxD\\MSTCP"
|
| -#define WIN_NS_NT_KEY SERVICES_KEY "Tcpip\\Parameters"
|
| -
|
| -static int
|
| -load_nameservers_from_registry(void)
|
| -{
|
| - int found = 0;
|
| - int r;
|
| -#define TRY(k, name) \
|
| - if (!found && config_nameserver_from_reg_key(k,name) == 0) { \
|
| - log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name); \
|
| - found = 1; \
|
| - } else if (!found) { \
|
| - log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s", \
|
| - #k,#name); \
|
| - }
|
| -
|
| - if (((int)GetVersion()) > 0) { /* NT */
|
| - HKEY nt_key = 0, interfaces_key = 0;
|
| -
|
| - if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
|
| - KEY_READ, &nt_key) != ERROR_SUCCESS) {
|
| - log(EVDNS_LOG_DEBUG,"Couldn't open nt key, %d",(int)GetLastError());
|
| - return -1;
|
| - }
|
| - r = RegOpenKeyExA(nt_key, "Interfaces", 0,
|
| - KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS,
|
| - &interfaces_key);
|
| - if (r != ERROR_SUCCESS) {
|
| - log(EVDNS_LOG_DEBUG,"Couldn't open interfaces key, %d",(int)GetLastError());
|
| - return -1;
|
| - }
|
| - TRY(nt_key, "NameServer");
|
| - TRY(nt_key, "DhcpNameServer");
|
| - TRY(interfaces_key, "NameServer");
|
| - TRY(interfaces_key, "DhcpNameServer");
|
| - RegCloseKey(interfaces_key);
|
| - RegCloseKey(nt_key);
|
| - } else {
|
| - HKEY win_key = 0;
|
| - if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, WIN_NS_9X_KEY, 0,
|
| - KEY_READ, &win_key) != ERROR_SUCCESS) {
|
| - log(EVDNS_LOG_DEBUG, "Couldn't open registry key, %d", (int)GetLastError());
|
| - return -1;
|
| - }
|
| - TRY(win_key, "NameServer");
|
| - RegCloseKey(win_key);
|
| - }
|
| -
|
| - if (found == 0) {
|
| - log(EVDNS_LOG_WARN,"Didn't find any nameservers.");
|
| - }
|
| -
|
| - return found ? 0 : -1;
|
| -#undef TRY
|
| -}
|
| -
|
| -int
|
| -evdns_config_windows_nameservers(void)
|
| -{
|
| - if (load_nameservers_with_getnetworkparams() == 0)
|
| - return 0;
|
| - return load_nameservers_from_registry();
|
| -}
|
| -#endif
|
| -
|
| -int
|
| -evdns_init(void)
|
| -{
|
| - int res = 0;
|
| -#ifdef WIN32
|
| - res = evdns_config_windows_nameservers();
|
| -#else
|
| - res = evdns_resolv_conf_parse(DNS_OPTIONS_ALL, "/etc/resolv.conf");
|
| -#endif
|
| -
|
| - return (res);
|
| -}
|
| -
|
| -const char *
|
| -evdns_err_to_string(int err)
|
| -{
|
| - switch (err) {
|
| - case DNS_ERR_NONE: return "no error";
|
| - case DNS_ERR_FORMAT: return "misformatted query";
|
| - case DNS_ERR_SERVERFAILED: return "server failed";
|
| - case DNS_ERR_NOTEXIST: return "name does not exist";
|
| - case DNS_ERR_NOTIMPL: return "query not implemented";
|
| - case DNS_ERR_REFUSED: return "refused";
|
| -
|
| - case DNS_ERR_TRUNCATED: return "reply truncated or ill-formed";
|
| - case DNS_ERR_UNKNOWN: return "unknown";
|
| - case DNS_ERR_TIMEOUT: return "request timed out";
|
| - case DNS_ERR_SHUTDOWN: return "dns subsystem shut down";
|
| - default: return "[Unknown error code]";
|
| - }
|
| -}
|
| -
|
| -void
|
| -evdns_shutdown(int fail_requests)
|
| -{
|
| - struct nameserver *server, *server_next;
|
| - struct search_domain *dom, *dom_next;
|
| -
|
| - while (req_head) {
|
| - if (fail_requests)
|
| - reply_callback(req_head, 0, DNS_ERR_SHUTDOWN, NULL);
|
| - request_finished(req_head, &req_head);
|
| - }
|
| - while (req_waiting_head) {
|
| - if (fail_requests)
|
| - reply_callback(req_waiting_head, 0, DNS_ERR_SHUTDOWN, NULL);
|
| - request_finished(req_waiting_head, &req_waiting_head);
|
| - }
|
| - global_requests_inflight = global_requests_waiting = 0;
|
| -
|
| - for (server = server_head; server; server = server_next) {
|
| - server_next = server->next;
|
| - if (server->socket >= 0)
|
| - CLOSE_SOCKET(server->socket);
|
| - (void) event_del(&server->event);
|
| - if (server->state == 0)
|
| - (void) event_del(&server->timeout_event);
|
| - free(server);
|
| - if (server_next == server_head)
|
| - break;
|
| - }
|
| - server_head = NULL;
|
| - global_good_nameservers = 0;
|
| -
|
| - if (global_search_state) {
|
| - for (dom = global_search_state->head; dom; dom = dom_next) {
|
| - dom_next = dom->next;
|
| - free(dom);
|
| - }
|
| - free(global_search_state);
|
| - global_search_state = NULL;
|
| - }
|
| - evdns_log_fn = NULL;
|
| -}
|
| -
|
| -#ifdef EVDNS_MAIN
|
| -void
|
| -main_callback(int result, char type, int count, int ttl,
|
| - void *addrs, void *orig) {
|
| - char *n = (char*)orig;
|
| - int i;
|
| - for (i = 0; i < count; ++i) {
|
| - if (type == DNS_IPv4_A) {
|
| - printf("%s: %s\n", n, debug_ntoa(((u32*)addrs)[i]));
|
| - } else if (type == DNS_PTR) {
|
| - printf("%s: %s\n", n, ((char**)addrs)[i]);
|
| - }
|
| - }
|
| - if (!count) {
|
| - printf("%s: No answer (%d)\n", n, result);
|
| - }
|
| - fflush(stdout);
|
| -}
|
| -void
|
| -evdns_server_callback(struct evdns_server_request *req, void *data)
|
| -{
|
| - int i, r;
|
| - (void)data;
|
| - /* dummy; give 192.168.11.11 as an answer for all A questions,
|
| - * give foo.bar.example.com as an answer for all PTR questions. */
|
| - for (i = 0; i < req->nquestions; ++i) {
|
| - u32 ans = htonl(0xc0a80b0bUL);
|
| - if (req->questions[i]->type == EVDNS_TYPE_A &&
|
| - req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
|
| - printf(" -- replying for %s (A)\n", req->questions[i]->name);
|
| - r = evdns_server_request_add_a_reply(req, req->questions[i]->name,
|
| - 1, &ans, 10);
|
| - if (r<0)
|
| - printf("eeep, didn't work.\n");
|
| - } else if (req->questions[i]->type == EVDNS_TYPE_PTR &&
|
| - req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
|
| - printf(" -- replying for %s (PTR)\n", req->questions[i]->name);
|
| - r = evdns_server_request_add_ptr_reply(req, NULL, req->questions[i]->name,
|
| - "foo.bar.example.com", 10);
|
| - } else {
|
| - printf(" -- skipping %s [%d %d]\n", req->questions[i]->name,
|
| - req->questions[i]->type, req->questions[i]->dns_question_class);
|
| - }
|
| - }
|
| -
|
| - r = evdns_request_respond(req, 0);
|
| - if (r<0)
|
| - printf("eeek, couldn't send reply.\n");
|
| -}
|
| -
|
| -void
|
| -logfn(int is_warn, const char *msg) {
|
| - (void) is_warn;
|
| - fprintf(stderr, "%s\n", msg);
|
| -}
|
| -int
|
| -main(int c, char **v) {
|
| - int idx;
|
| - int reverse = 0, verbose = 1, servertest = 0;
|
| - if (c<2) {
|
| - fprintf(stderr, "syntax: %s [-x] [-v] hostname\n", v[0]);
|
| - fprintf(stderr, "syntax: %s [-servertest]\n", v[0]);
|
| - return 1;
|
| - }
|
| - idx = 1;
|
| - while (idx < c && v[idx][0] == '-') {
|
| - if (!strcmp(v[idx], "-x"))
|
| - reverse = 1;
|
| - else if (!strcmp(v[idx], "-v"))
|
| - verbose = 1;
|
| - else if (!strcmp(v[idx], "-servertest"))
|
| - servertest = 1;
|
| - else
|
| - fprintf(stderr, "Unknown option %s\n", v[idx]);
|
| - ++idx;
|
| - }
|
| - event_init();
|
| - if (verbose)
|
| - evdns_set_log_fn(logfn);
|
| - evdns_resolv_conf_parse(DNS_OPTION_NAMESERVERS, "/etc/resolv.conf");
|
| - if (servertest) {
|
| - int sock;
|
| - struct sockaddr_in my_addr;
|
| - sock = socket(PF_INET, SOCK_DGRAM, 0);
|
| - evutil_make_socket_nonblocking(sock);
|
| - my_addr.sin_family = AF_INET;
|
| - my_addr.sin_port = htons(10053);
|
| - my_addr.sin_addr.s_addr = INADDR_ANY;
|
| - if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr))<0) {
|
| - perror("bind");
|
| - exit(1);
|
| - }
|
| - evdns_add_server_port(sock, 0, evdns_server_callback, NULL);
|
| - }
|
| - for (; idx < c; ++idx) {
|
| - if (reverse) {
|
| - struct in_addr addr;
|
| - if (!inet_aton(v[idx], &addr)) {
|
| - fprintf(stderr, "Skipping non-IP %s\n", v[idx]);
|
| - continue;
|
| - }
|
| - fprintf(stderr, "resolving %s...\n",v[idx]);
|
| - evdns_resolve_reverse(&addr, 0, main_callback, v[idx]);
|
| - } else {
|
| - fprintf(stderr, "resolving (fwd) %s...\n",v[idx]);
|
| - evdns_resolve_ipv4(v[idx], 0, main_callback, v[idx]);
|
| - }
|
| - }
|
| - fflush(stdout);
|
| - event_dispatch();
|
| - return 0;
|
| -}
|
| -#endif
|
|
|
Chromium Code Reviews
Issue 1531573008:
move libevent into base (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master