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Diffstat (limited to '3rdParty/CAres/src/ares_process.c')
-rw-r--r--3rdParty/CAres/src/ares_process.c1170
1 files changed, 0 insertions, 1170 deletions
diff --git a/3rdParty/CAres/src/ares_process.c b/3rdParty/CAres/src/ares_process.c
deleted file mode 100644
index 6182ccc..0000000
--- a/3rdParty/CAres/src/ares_process.c
+++ /dev/null
@@ -1,1170 +0,0 @@
-/* $Id: ares_process.c,v 1.79 2009-11-18 10:33:54 yangtse Exp $ */
-
-/* Copyright 1998 by the Massachusetts Institute of Technology.
- * Copyright (C) 2004-2009 by Daniel Stenberg
- *
- * Permission to use, copy, modify, and distribute this
- * software and its documentation for any purpose and without
- * fee is hereby granted, provided that the above copyright
- * notice appear in all copies and that both that copyright
- * notice and this permission notice appear in supporting
- * documentation, and that the name of M.I.T. not be used in
- * advertising or publicity pertaining to distribution of the
- * software without specific, written prior permission.
- * M.I.T. makes no representations about the suitability of
- * this software for any purpose. It is provided "as is"
- * without express or implied warranty.
- */
-
-#include "ares_setup.h"
-
-#ifdef HAVE_SYS_SOCKET_H
-# include <sys/socket.h>
-#endif
-#ifdef HAVE_SYS_UIO_H
-# include <sys/uio.h>
-#endif
-#ifdef HAVE_NETINET_IN_H
-# include <netinet/in.h>
-#endif
-#ifdef HAVE_NETINET_TCP_H
-# include <netinet/tcp.h>
-#endif
-#ifdef HAVE_NETDB_H
-# include <netdb.h>
-#endif
-#ifdef HAVE_ARPA_NAMESER_H
-# include <arpa/nameser.h>
-#else
-# include "nameser.h"
-#endif
-#ifdef HAVE_ARPA_NAMESER_COMPAT_H
-# include <arpa/nameser_compat.h>
-#endif
-
-#ifdef HAVE_SYS_TIME_H
-# include <sys/time.h>
-#endif
-
-#ifdef HAVE_STRINGS_H
-# include <strings.h>
-#endif
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-#ifdef HAVE_SYS_IOCTL_H
-# include <sys/ioctl.h>
-#endif
-#ifdef NETWARE
-# include <sys/filio.h>
-#endif
-
-#include <assert.h>
-#include <string.h>
-#include <stdlib.h>
-#include <fcntl.h>
-#include <time.h>
-#include <errno.h>
-
-#include "ares.h"
-#include "ares_dns.h"
-#include "ares_private.h"
-
-
-static int try_again(int errnum);
-static void write_tcp_data(ares_channel channel, fd_set *write_fds,
- ares_socket_t write_fd, struct timeval *now);
-static void read_tcp_data(ares_channel channel, fd_set *read_fds,
- ares_socket_t read_fd, struct timeval *now);
-static void read_udp_packets(ares_channel channel, fd_set *read_fds,
- ares_socket_t read_fd, struct timeval *now);
-static void advance_tcp_send_queue(ares_channel channel, int whichserver,
- ssize_t num_bytes);
-static void process_timeouts(ares_channel channel, struct timeval *now);
-static void process_broken_connections(ares_channel channel,
- struct timeval *now);
-static void process_answer(ares_channel channel, unsigned char *abuf,
- int alen, int whichserver, int tcp,
- struct timeval *now);
-static void handle_error(ares_channel channel, int whichserver,
- struct timeval *now);
-static void skip_server(ares_channel channel, struct query *query,
- int whichserver);
-static void next_server(ares_channel channel, struct query *query,
- struct timeval *now);
-static int configure_socket(int s, ares_channel channel);
-static int open_tcp_socket(ares_channel channel, struct server_state *server);
-static int open_udp_socket(ares_channel channel, struct server_state *server);
-static int same_questions(const unsigned char *qbuf, int qlen,
- const unsigned char *abuf, int alen);
-static void end_query(ares_channel channel, struct query *query, int status,
- unsigned char *abuf, int alen);
-
-/* return true if now is exactly check time or later */
-int ares__timedout(struct timeval *now,
- struct timeval *check)
-{
- long secs = (now->tv_sec - check->tv_sec);
-
- if(secs > 0)
- return 1; /* yes, timed out */
- if(secs < 0)
- return 0; /* nope, not timed out */
-
- /* if the full seconds were identical, check the sub second parts */
- return (now->tv_usec - check->tv_usec >= 0);
-}
-
-/* add the specific number of milliseconds to the time in the first argument */
-int ares__timeadd(struct timeval *now,
- int millisecs)
-{
- now->tv_sec += millisecs/1000;
- now->tv_usec += (millisecs%1000)*1000;
-
- if(now->tv_usec >= 1000000) {
- ++(now->tv_sec);
- now->tv_usec -= 1000000;
- }
-
- return 0;
-}
-
-/* return time offset between now and (future) check, in milliseconds */
-long ares__timeoffset(struct timeval *now,
- struct timeval *check)
-{
- return (check->tv_sec - now->tv_sec)*1000 +
- (check->tv_usec - now->tv_usec)/1000;
-}
-
-
-/* Something interesting happened on the wire, or there was a timeout.
- * See what's up and respond accordingly.
- */
-void ares_process(ares_channel channel, fd_set *read_fds, fd_set *write_fds)
-{
- struct timeval now = ares__tvnow();
-
- write_tcp_data(channel, write_fds, ARES_SOCKET_BAD, &now);
- read_tcp_data(channel, read_fds, ARES_SOCKET_BAD, &now);
- read_udp_packets(channel, read_fds, ARES_SOCKET_BAD, &now);
- process_timeouts(channel, &now);
- process_broken_connections(channel, &now);
-}
-
-/* Something interesting happened on the wire, or there was a timeout.
- * See what's up and respond accordingly.
- */
-void ares_process_fd(ares_channel channel,
- ares_socket_t read_fd, /* use ARES_SOCKET_BAD or valid
- file descriptors */
- ares_socket_t write_fd)
-{
- struct timeval now = ares__tvnow();
-
- write_tcp_data(channel, NULL, write_fd, &now);
- read_tcp_data(channel, NULL, read_fd, &now);
- read_udp_packets(channel, NULL, read_fd, &now);
- process_timeouts(channel, &now);
-}
-
-
-/* Return 1 if the specified error number describes a readiness error, or 0
- * otherwise. This is mostly for HP-UX, which could return EAGAIN or
- * EWOULDBLOCK. See this man page
- *
- * http://devrsrc1.external.hp.com/STKS/cgi-bin/man2html?manpage=/usr/share/man/man2.Z/send.2
- */
-static int try_again(int errnum)
-{
-#if !defined EWOULDBLOCK && !defined EAGAIN
-#error "Neither EWOULDBLOCK nor EAGAIN defined"
-#endif
- switch (errnum)
- {
-#ifdef EWOULDBLOCK
- case EWOULDBLOCK:
- return 1;
-#endif
-#if defined EAGAIN && EAGAIN != EWOULDBLOCK
- case EAGAIN:
- return 1;
-#endif
- }
- return 0;
-}
-
-/* If any TCP sockets select true for writing, write out queued data
- * we have for them.
- */
-static void write_tcp_data(ares_channel channel,
- fd_set *write_fds,
- ares_socket_t write_fd,
- struct timeval *now)
-{
- struct server_state *server;
- struct send_request *sendreq;
- struct iovec *vec;
- int i;
- ssize_t scount;
- ssize_t wcount;
- size_t n;
-
- if(!write_fds && (write_fd == ARES_SOCKET_BAD))
- /* no possible action */
- return;
-
- for (i = 0; i < channel->nservers; i++)
- {
- /* Make sure server has data to send and is selected in write_fds or
- write_fd. */
- server = &channel->servers[i];
- if (!server->qhead || server->tcp_socket == ARES_SOCKET_BAD ||
- server->is_broken)
- continue;
-
- if(write_fds) {
- if(!FD_ISSET(server->tcp_socket, write_fds))
- continue;
- }
- else {
- if(server->tcp_socket != write_fd)
- continue;
- }
-
- if(write_fds)
- /* If there's an error and we close this socket, then open
- * another with the same fd to talk to another server, then we
- * don't want to think that it was the new socket that was
- * ready. This is not disastrous, but is likely to result in
- * extra system calls and confusion. */
- FD_CLR(server->tcp_socket, write_fds);
-
- /* Count the number of send queue items. */
- n = 0;
- for (sendreq = server->qhead; sendreq; sendreq = sendreq->next)
- n++;
-
- /* Allocate iovecs so we can send all our data at once. */
- vec = malloc(n * sizeof(struct iovec));
- if (vec)
- {
- /* Fill in the iovecs and send. */
- n = 0;
- for (sendreq = server->qhead; sendreq; sendreq = sendreq->next)
- {
- vec[n].iov_base = (char *) sendreq->data;
- vec[n].iov_len = sendreq->len;
- n++;
- }
- wcount = (ssize_t)writev(server->tcp_socket, vec, (int)n);
- free(vec);
- if (wcount < 0)
- {
- if (!try_again(SOCKERRNO))
- handle_error(channel, i, now);
- continue;
- }
-
- /* Advance the send queue by as many bytes as we sent. */
- advance_tcp_send_queue(channel, i, wcount);
- }
- else
- {
- /* Can't allocate iovecs; just send the first request. */
- sendreq = server->qhead;
-
- scount = swrite(server->tcp_socket, sendreq->data, sendreq->len);
- if (scount < 0)
- {
- if (!try_again(SOCKERRNO))
- handle_error(channel, i, now);
- continue;
- }
-
- /* Advance the send queue by as many bytes as we sent. */
- advance_tcp_send_queue(channel, i, scount);
- }
- }
-}
-
-/* Consume the given number of bytes from the head of the TCP send queue. */
-static void advance_tcp_send_queue(ares_channel channel, int whichserver,
- ssize_t num_bytes)
-{
- struct send_request *sendreq;
- struct server_state *server = &channel->servers[whichserver];
- while (num_bytes > 0)
- {
- sendreq = server->qhead;
- if ((size_t)num_bytes >= sendreq->len)
- {
- num_bytes -= sendreq->len;
- server->qhead = sendreq->next;
- if (server->qhead == NULL)
- {
- SOCK_STATE_CALLBACK(channel, server->tcp_socket, 1, 0);
- server->qtail = NULL;
- }
- if (sendreq->data_storage != NULL)
- free(sendreq->data_storage);
- free(sendreq);
- }
- else
- {
- sendreq->data += num_bytes;
- sendreq->len -= num_bytes;
- num_bytes = 0;
- }
- }
-}
-
-/* If any TCP socket selects true for reading, read some data,
- * allocate a buffer if we finish reading the length word, and process
- * a packet if we finish reading one.
- */
-static void read_tcp_data(ares_channel channel, fd_set *read_fds,
- ares_socket_t read_fd, struct timeval *now)
-{
- struct server_state *server;
- int i;
- ssize_t count;
-
- if(!read_fds && (read_fd == ARES_SOCKET_BAD))
- /* no possible action */
- return;
-
- for (i = 0; i < channel->nservers; i++)
- {
- /* Make sure the server has a socket and is selected in read_fds. */
- server = &channel->servers[i];
- if (server->tcp_socket == ARES_SOCKET_BAD || server->is_broken)
- continue;
-
- if(read_fds) {
- if(!FD_ISSET(server->tcp_socket, read_fds))
- continue;
- }
- else {
- if(server->tcp_socket != read_fd)
- continue;
- }
-
- if(read_fds)
- /* If there's an error and we close this socket, then open
- * another with the same fd to talk to another server, then we
- * don't want to think that it was the new socket that was
- * ready. This is not disastrous, but is likely to result in
- * extra system calls and confusion. */
- FD_CLR(server->tcp_socket, read_fds);
-
- if (server->tcp_lenbuf_pos != 2)
- {
- /* We haven't yet read a length word, so read that (or
- * what's left to read of it).
- */
- count = sread(server->tcp_socket,
- server->tcp_lenbuf + server->tcp_lenbuf_pos,
- 2 - server->tcp_lenbuf_pos);
- if (count <= 0)
- {
- if (!(count == -1 && try_again(SOCKERRNO)))
- handle_error(channel, i, now);
- continue;
- }
-
- server->tcp_lenbuf_pos += (int)count;
- if (server->tcp_lenbuf_pos == 2)
- {
- /* We finished reading the length word. Decode the
- * length and allocate a buffer for the data.
- */
- server->tcp_length = server->tcp_lenbuf[0] << 8
- | server->tcp_lenbuf[1];
- server->tcp_buffer = malloc(server->tcp_length);
- if (!server->tcp_buffer)
- handle_error(channel, i, now);
- server->tcp_buffer_pos = 0;
- }
- }
- else
- {
- /* Read data into the allocated buffer. */
- count = sread(server->tcp_socket,
- server->tcp_buffer + server->tcp_buffer_pos,
- server->tcp_length - server->tcp_buffer_pos);
- if (count <= 0)
- {
- if (!(count == -1 && try_again(SOCKERRNO)))
- handle_error(channel, i, now);
- continue;
- }
-
- server->tcp_buffer_pos += (int)count;
- if (server->tcp_buffer_pos == server->tcp_length)
- {
- /* We finished reading this answer; process it and
- * prepare to read another length word.
- */
- process_answer(channel, server->tcp_buffer, server->tcp_length,
- i, 1, now);
- if (server->tcp_buffer)
- free(server->tcp_buffer);
- server->tcp_buffer = NULL;
- server->tcp_lenbuf_pos = 0;
- server->tcp_buffer_pos = 0;
- }
- }
- }
-}
-
-/* If any UDP sockets select true for reading, process them. */
-static void read_udp_packets(ares_channel channel, fd_set *read_fds,
- ares_socket_t read_fd, struct timeval *now)
-{
- struct server_state *server;
- int i;
- ssize_t count;
- unsigned char buf[PACKETSZ + 1];
-#ifdef HAVE_RECVFROM
- struct sockaddr_in from;
- ares_socklen_t fromlen;
-#endif
-
- if(!read_fds && (read_fd == ARES_SOCKET_BAD))
- /* no possible action */
- return;
-
- for (i = 0; i < channel->nservers; i++)
- {
- /* Make sure the server has a socket and is selected in read_fds. */
- server = &channel->servers[i];
-
- if (server->udp_socket == ARES_SOCKET_BAD || server->is_broken)
- continue;
-
- if(read_fds) {
- if(!FD_ISSET(server->udp_socket, read_fds))
- continue;
- }
- else {
- if(server->udp_socket != read_fd)
- continue;
- }
-
- if(read_fds)
- /* If there's an error and we close this socket, then open
- * another with the same fd to talk to another server, then we
- * don't want to think that it was the new socket that was
- * ready. This is not disastrous, but is likely to result in
- * extra system calls and confusion. */
- FD_CLR(server->udp_socket, read_fds);
-
- /* To reduce event loop overhead, read and process as many
- * packets as we can. */
- do {
-#ifdef HAVE_RECVFROM
- fromlen = sizeof(from);
- count = (ssize_t)recvfrom(server->udp_socket, (void *)buf, sizeof(buf),
- 0, (struct sockaddr *)&from, &fromlen);
-#else
- count = sread(server->udp_socket, buf, sizeof(buf));
-#endif
- if (count == -1 && try_again(SOCKERRNO))
- continue;
- else if (count <= 0)
- handle_error(channel, i, now);
-#ifdef HAVE_RECVFROM
- else if (from.sin_addr.s_addr != server->addr.s_addr)
- /* Address response came from did not match the address
- * we sent the request to. Someone may be attempting
- * to perform a cache poisoning attack */
- break;
-#endif
- else
- process_answer(channel, buf, (int)count, i, 0, now);
- } while (count > 0);
- }
-}
-
-/* If any queries have timed out, note the timeout and move them on. */
-static void process_timeouts(ares_channel channel, struct timeval *now)
-{
- time_t t; /* the time of the timeouts we're processing */
- struct query *query;
- struct list_node* list_head;
- struct list_node* list_node;
-
- /* Process all the timeouts that have fired since the last time we
- * processed timeouts. If things are going well, then we'll have
- * hundreds/thousands of queries that fall into future buckets, and
- * only a handful of requests that fall into the "now" bucket, so
- * this should be quite quick.
- */
- for (t = channel->last_timeout_processed; t <= now->tv_sec; t++)
- {
- list_head = &(channel->queries_by_timeout[t % ARES_TIMEOUT_TABLE_SIZE]);
- for (list_node = list_head->next; list_node != list_head; )
- {
- query = list_node->data;
- list_node = list_node->next; /* in case the query gets deleted */
- if (query->timeout.tv_sec && ares__timedout(now, &query->timeout))
- {
- query->error_status = ARES_ETIMEOUT;
- ++query->timeouts;
- next_server(channel, query, now);
- }
- }
- }
- channel->last_timeout_processed = now->tv_sec;
-}
-
-/* Handle an answer from a server. */
-static void process_answer(ares_channel channel, unsigned char *abuf,
- int alen, int whichserver, int tcp,
- struct timeval *now)
-{
- int tc, rcode;
- unsigned short id;
- struct query *query;
- struct list_node* list_head;
- struct list_node* list_node;
-
- /* If there's no room in the answer for a header, we can't do much
- * with it. */
- if (alen < HFIXEDSZ)
- return;
-
- /* Grab the query ID, truncate bit, and response code from the packet. */
- id = DNS_HEADER_QID(abuf);
- tc = DNS_HEADER_TC(abuf);
- rcode = DNS_HEADER_RCODE(abuf);
-
- /* Find the query corresponding to this packet. The queries are
- * hashed/bucketed by query id, so this lookup should be quick.
- * Note that both the query id and the questions must be the same;
- * when the query id wraps around we can have multiple outstanding
- * queries with the same query id, so we need to check both the id and
- * question.
- */
- query = NULL;
- list_head = &(channel->queries_by_qid[id % ARES_QID_TABLE_SIZE]);
- for (list_node = list_head->next; list_node != list_head;
- list_node = list_node->next)
- {
- struct query *q = list_node->data;
- if ((q->qid == id) && same_questions(q->qbuf, q->qlen, abuf, alen))
- {
- query = q;
- break;
- }
- }
- if (!query)
- return;
-
- /* If we got a truncated UDP packet and are not ignoring truncation,
- * don't accept the packet, and switch the query to TCP if we hadn't
- * done so already.
- */
- if ((tc || alen > PACKETSZ) && !tcp && !(channel->flags & ARES_FLAG_IGNTC))
- {
- if (!query->using_tcp)
- {
- query->using_tcp = 1;
- ares__send_query(channel, query, now);
- }
- return;
- }
-
- /* Limit alen to PACKETSZ if we aren't using TCP (only relevant if we
- * are ignoring truncation.
- */
- if (alen > PACKETSZ && !tcp)
- alen = PACKETSZ;
-
- /* If we aren't passing through all error packets, discard packets
- * with SERVFAIL, NOTIMP, or REFUSED response codes.
- */
- if (!(channel->flags & ARES_FLAG_NOCHECKRESP))
- {
- if (rcode == SERVFAIL || rcode == NOTIMP || rcode == REFUSED)
- {
- skip_server(channel, query, whichserver);
- if (query->server == whichserver)
- next_server(channel, query, now);
- return;
- }
- }
-
- end_query(channel, query, ARES_SUCCESS, abuf, alen);
-}
-
-/* Close all the connections that are no longer usable. */
-static void process_broken_connections(ares_channel channel,
- struct timeval *now)
-{
- int i;
- for (i = 0; i < channel->nservers; i++)
- {
- struct server_state *server = &channel->servers[i];
- if (server->is_broken)
- {
- handle_error(channel, i, now);
- }
- }
-}
-
-static void handle_error(ares_channel channel, int whichserver,
- struct timeval *now)
-{
- struct server_state *server;
- struct query *query;
- struct list_node list_head;
- struct list_node* list_node;
-
- server = &channel->servers[whichserver];
-
- /* Reset communications with this server. */
- ares__close_sockets(channel, server);
-
- /* Tell all queries talking to this server to move on and not try
- * this server again. We steal the current list of queries that were
- * in-flight to this server, since when we call next_server this can
- * cause the queries to be re-sent to this server, which will
- * re-insert these queries in that same server->queries_to_server
- * list.
- */
- ares__init_list_head(&list_head);
- ares__swap_lists(&list_head, &(server->queries_to_server));
- for (list_node = list_head.next; list_node != &list_head; )
- {
- query = list_node->data;
- list_node = list_node->next; /* in case the query gets deleted */
- assert(query->server == whichserver);
- skip_server(channel, query, whichserver);
- next_server(channel, query, now);
- }
- /* Each query should have removed itself from our temporary list as
- * it re-sent itself or finished up...
- */
- assert(ares__is_list_empty(&list_head));
-}
-
-static void skip_server(ares_channel channel, struct query *query,
- int whichserver) {
- /* The given server gave us problems with this query, so if we have
- * the luxury of using other servers, then let's skip the
- * potentially broken server and just use the others. If we only
- * have one server and we need to retry then we should just go ahead
- * and re-use that server, since it's our only hope; perhaps we
- * just got unlucky, and retrying will work (eg, the server timed
- * out our TCP connection just as we were sending another request).
- */
- if (channel->nservers > 1)
- {
- query->server_info[whichserver].skip_server = 1;
- }
-}
-
-static void next_server(ares_channel channel, struct query *query,
- struct timeval *now)
-{
- /* We need to try each server channel->tries times. We have channel->nservers
- * servers to try. In total, we need to do channel->nservers * channel->tries
- * attempts. Use query->try to remember how many times we already attempted
- * this query. Use modular arithmetic to find the next server to try. */
- while (++(query->try) < (channel->nservers * channel->tries))
- {
- struct server_state *server;
-
- /* Move on to the next server. */
- query->server = (query->server + 1) % channel->nservers;
- server = &channel->servers[query->server];
-
- /* We don't want to use this server if (1) we decided this
- * connection is broken, and thus about to be closed, (2)
- * we've decided to skip this server because of earlier
- * errors we encountered, or (3) we already sent this query
- * over this exact connection.
- */
- if (!server->is_broken &&
- !query->server_info[query->server].skip_server &&
- !(query->using_tcp &&
- (query->server_info[query->server].tcp_connection_generation ==
- server->tcp_connection_generation)))
- {
- ares__send_query(channel, query, now);
- return;
- }
-
- /* You might think that with TCP we only need one try. However,
- * even when using TCP, servers can time-out our connection just
- * as we're sending a request, or close our connection because
- * they die, or never send us a reply because they get wedged or
- * tickle a bug that drops our request.
- */
- }
-
- /* If we are here, all attempts to perform query failed. */
- end_query(channel, query, query->error_status, NULL, 0);
-}
-
-void ares__send_query(ares_channel channel, struct query *query,
- struct timeval *now)
-{
- struct send_request *sendreq;
- struct server_state *server;
- int timeplus;
-
- server = &channel->servers[query->server];
- if (query->using_tcp)
- {
- /* Make sure the TCP socket for this server is set up and queue
- * a send request.
- */
- if (server->tcp_socket == ARES_SOCKET_BAD)
- {
- if (open_tcp_socket(channel, server) == -1)
- {
- skip_server(channel, query, query->server);
- next_server(channel, query, now);
- return;
- }
- }
- sendreq = calloc(1, sizeof(struct send_request));
- if (!sendreq)
- {
- end_query(channel, query, ARES_ENOMEM, NULL, 0);
- return;
- }
- /* To make the common case fast, we avoid copies by using the
- * query's tcpbuf for as long as the query is alive. In the rare
- * case where the query ends while it's queued for transmission,
- * then we give the sendreq its own copy of the request packet
- * and put it in sendreq->data_storage.
- */
- sendreq->data_storage = NULL;
- sendreq->data = query->tcpbuf;
- sendreq->len = query->tcplen;
- sendreq->owner_query = query;
- sendreq->next = NULL;
- if (server->qtail)
- server->qtail->next = sendreq;
- else
- {
- SOCK_STATE_CALLBACK(channel, server->tcp_socket, 1, 1);
- server->qhead = sendreq;
- }
- server->qtail = sendreq;
- query->server_info[query->server].tcp_connection_generation =
- server->tcp_connection_generation;
- }
- else
- {
- if (server->udp_socket == ARES_SOCKET_BAD)
- {
- if (open_udp_socket(channel, server) == -1)
- {
- skip_server(channel, query, query->server);
- next_server(channel, query, now);
- return;
- }
- }
- if (swrite(server->udp_socket, query->qbuf, query->qlen) == -1)
- {
- /* FIXME: Handle EAGAIN here since it likely can happen. */
- skip_server(channel, query, query->server);
- next_server(channel, query, now);
- return;
- }
- }
- timeplus = channel->timeout << (query->try / channel->nservers);
- timeplus = (timeplus * (9 + (rand () & 7))) / 16;
- query->timeout = *now;
- ares__timeadd(&query->timeout,
- timeplus);
- /* Keep track of queries bucketed by timeout, so we can process
- * timeout events quickly.
- */
- ares__remove_from_list(&(query->queries_by_timeout));
- ares__insert_in_list(
- &(query->queries_by_timeout),
- &(channel->queries_by_timeout[query->timeout.tv_sec %
- ARES_TIMEOUT_TABLE_SIZE]));
-
- /* Keep track of queries bucketed by server, so we can process server
- * errors quickly.
- */
- ares__remove_from_list(&(query->queries_to_server));
- ares__insert_in_list(&(query->queries_to_server),
- &(server->queries_to_server));
-}
-
-/*
- * setsocknonblock sets the given socket to either blocking or non-blocking mode
- * based on the 'nonblock' boolean argument. This function is highly portable.
- */
-static int setsocknonblock(ares_socket_t sockfd, /* operate on this */
- int nonblock /* TRUE or FALSE */)
-{
-#if defined(USE_BLOCKING_SOCKETS)
-
- return 0; /* returns success */
-
-#elif defined(HAVE_FCNTL_O_NONBLOCK)
-
- /* most recent unix versions */
- int flags;
- flags = fcntl(sockfd, F_GETFL, 0);
- if (FALSE != nonblock)
- return fcntl(sockfd, F_SETFL, flags | O_NONBLOCK);
- else
- return fcntl(sockfd, F_SETFL, flags & (~O_NONBLOCK));
-
-#elif defined(HAVE_IOCTL_FIONBIO)
-
- /* older unix versions */
- int flags;
- flags = nonblock;
- return ioctl(sockfd, FIONBIO, &flags);
-
-#elif defined(HAVE_IOCTLSOCKET_FIONBIO)
-
-#ifdef WATT32
- char flags;
-#else
- /* Windows */
- unsigned long flags;
-#endif
- flags = nonblock;
- return ioctlsocket(sockfd, FIONBIO, &flags);
-
-#elif defined(HAVE_IOCTLSOCKET_CAMEL_FIONBIO)
-
- /* Amiga */
- return IoctlSocket(sockfd, FIONBIO, (long)nonblock);
-
-#elif defined(HAVE_SETSOCKOPT_SO_NONBLOCK)
-
- /* BeOS */
- long b = nonblock ? 1 : 0;
- return setsockopt(sockfd, SOL_SOCKET, SO_NONBLOCK, &b, sizeof(b));
-
-#else
-# error "no non-blocking method was found/used/set"
-#endif
-}
-
-static int configure_socket(int s, ares_channel channel)
-{
- setsocknonblock(s, TRUE);
-
-#if defined(FD_CLOEXEC) && !defined(MSDOS)
- /* Configure the socket fd as close-on-exec. */
- if (fcntl(s, F_SETFD, FD_CLOEXEC) == -1)
- return -1;
-#endif
-
- /* Set the socket's send and receive buffer sizes. */
- if ((channel->socket_send_buffer_size > 0) &&
- setsockopt(s, SOL_SOCKET, SO_SNDBUF,
- (void *)&channel->socket_send_buffer_size,
- sizeof(channel->socket_send_buffer_size)) == -1)
- return -1;
-
- if ((channel->socket_receive_buffer_size > 0) &&
- setsockopt(s, SOL_SOCKET, SO_RCVBUF,
- (void *)&channel->socket_receive_buffer_size,
- sizeof(channel->socket_receive_buffer_size)) == -1)
- return -1;
-
- return 0;
- }
-
-static int open_tcp_socket(ares_channel channel, struct server_state *server)
-{
- ares_socket_t s;
- int opt;
- struct sockaddr_in sockin;
-
- /* Acquire a socket. */
- s = socket(AF_INET, SOCK_STREAM, 0);
- if (s == ARES_SOCKET_BAD)
- return -1;
-
- /* Configure it. */
- if (configure_socket(s, channel) < 0)
- {
- sclose(s);
- return -1;
- }
-
-#ifdef TCP_NODELAY
- /*
- * Disable the Nagle algorithm (only relevant for TCP sockets, and thus not in
- * configure_socket). In general, in DNS lookups we're pretty much interested
- * in firing off a single request and then waiting for a reply, so batching
- * isn't very interesting in general.
- */
- opt = 1;
- if (setsockopt(s, IPPROTO_TCP, TCP_NODELAY,
- (void *)&opt, sizeof(opt)) == -1)
- {
- sclose(s);
- return -1;
- }
-#endif
-
- /* Connect to the server. */
- memset(&sockin, 0, sizeof(sockin));
- sockin.sin_family = AF_INET;
- sockin.sin_addr = server->addr;
- sockin.sin_port = (unsigned short)(channel->tcp_port & 0xffff);
- if (connect(s, (struct sockaddr *) &sockin, sizeof(sockin)) == -1)
- {
- int err = SOCKERRNO;
-
- if (err != EINPROGRESS && err != EWOULDBLOCK)
- {
- sclose(s);
- return -1;
- }
- }
-
- if (channel->sock_create_cb)
- {
- int err = channel->sock_create_cb(s, SOCK_STREAM,
- channel->sock_create_cb_data);
- if (err < 0)
- {
- sclose(s);
- return err;
- }
- }
-
- SOCK_STATE_CALLBACK(channel, s, 1, 0);
- server->tcp_buffer_pos = 0;
- server->tcp_socket = s;
- server->tcp_connection_generation = ++channel->tcp_connection_generation;
- return 0;
-}
-
-static int open_udp_socket(ares_channel channel, struct server_state *server)
-{
- ares_socket_t s;
- struct sockaddr_in sockin;
-
- /* Acquire a socket. */
- s = socket(AF_INET, SOCK_DGRAM, 0);
- if (s == ARES_SOCKET_BAD)
- return -1;
-
- /* Set the socket non-blocking. */
- if (configure_socket(s, channel) < 0)
- {
- sclose(s);
- return -1;
- }
-
- /* Connect to the server. */
- memset(&sockin, 0, sizeof(sockin));
- sockin.sin_family = AF_INET;
- sockin.sin_addr = server->addr;
- sockin.sin_port = (unsigned short)(channel->udp_port & 0xffff);
- if (connect(s, (struct sockaddr *) &sockin, sizeof(sockin)) == -1)
- {
- int err = SOCKERRNO;
-
- if (err != EINPROGRESS && err != EWOULDBLOCK)
- {
- sclose(s);
- return -1;
- }
- }
-
- if (channel->sock_create_cb)
- {
- int err = channel->sock_create_cb(s, SOCK_DGRAM,
- channel->sock_create_cb_data);
- if (err < 0)
- {
- sclose(s);
- return err;
- }
- }
-
- SOCK_STATE_CALLBACK(channel, s, 1, 0);
-
- server->udp_socket = s;
- return 0;
-}
-
-static int same_questions(const unsigned char *qbuf, int qlen,
- const unsigned char *abuf, int alen)
-{
- struct {
- const unsigned char *p;
- int qdcount;
- char *name;
- long namelen;
- int type;
- int dnsclass;
- } q, a;
- int i, j;
-
- if (qlen < HFIXEDSZ || alen < HFIXEDSZ)
- return 0;
-
- /* Extract qdcount from the request and reply buffers and compare them. */
- q.qdcount = DNS_HEADER_QDCOUNT(qbuf);
- a.qdcount = DNS_HEADER_QDCOUNT(abuf);
- if (q.qdcount != a.qdcount)
- return 0;
-
- /* For each question in qbuf, find it in abuf. */
- q.p = qbuf + HFIXEDSZ;
- for (i = 0; i < q.qdcount; i++)
- {
- /* Decode the question in the query. */
- if (ares_expand_name(q.p, qbuf, qlen, &q.name, &q.namelen)
- != ARES_SUCCESS)
- return 0;
- q.p += q.namelen;
- if (q.p + QFIXEDSZ > qbuf + qlen)
- {
- free(q.name);
- return 0;
- }
- q.type = DNS_QUESTION_TYPE(q.p);
- q.dnsclass = DNS_QUESTION_CLASS(q.p);
- q.p += QFIXEDSZ;
-
- /* Search for this question in the answer. */
- a.p = abuf + HFIXEDSZ;
- for (j = 0; j < a.qdcount; j++)
- {
- /* Decode the question in the answer. */
- if (ares_expand_name(a.p, abuf, alen, &a.name, &a.namelen)
- != ARES_SUCCESS)
- {
- free(q.name);
- return 0;
- }
- a.p += a.namelen;
- if (a.p + QFIXEDSZ > abuf + alen)
- {
- free(q.name);
- free(a.name);
- return 0;
- }
- a.type = DNS_QUESTION_TYPE(a.p);
- a.dnsclass = DNS_QUESTION_CLASS(a.p);
- a.p += QFIXEDSZ;
-
- /* Compare the decoded questions. */
- if (strcasecmp(q.name, a.name) == 0 && q.type == a.type
- && q.dnsclass == a.dnsclass)
- {
- free(a.name);
- break;
- }
- free(a.name);
- }
-
- free(q.name);
- if (j == a.qdcount)
- return 0;
- }
- return 1;
-}
-
-static void end_query (ares_channel channel, struct query *query, int status,
- unsigned char *abuf, int alen)
-{
- int i;
-
- /* First we check to see if this query ended while one of our send
- * queues still has pointers to it.
- */
- for (i = 0; i < channel->nservers; i++)
- {
- struct server_state *server = &channel->servers[i];
- struct send_request *sendreq;
- for (sendreq = server->qhead; sendreq; sendreq = sendreq->next)
- if (sendreq->owner_query == query)
- {
- sendreq->owner_query = NULL;
- assert(sendreq->data_storage == NULL);
- if (status == ARES_SUCCESS)
- {
- /* We got a reply for this query, but this queued
- * sendreq points into this soon-to-be-gone query's
- * tcpbuf. Probably this means we timed out and queued
- * the query for retransmission, then received a
- * response before actually retransmitting. This is
- * perfectly fine, so we want to keep the connection
- * running smoothly if we can. But in the worst case
- * we may have sent only some prefix of the query,
- * with some suffix of the query left to send. Also,
- * the buffer may be queued on multiple queues. To
- * prevent dangling pointers to the query's tcpbuf and
- * handle these cases, we just give such sendreqs
- * their own copy of the query packet.
- */
- sendreq->data_storage = malloc(sendreq->len);
- if (sendreq->data_storage != NULL)
- {
- memcpy(sendreq->data_storage, sendreq->data, sendreq->len);
- sendreq->data = sendreq->data_storage;
- }
- }
- if ((status != ARES_SUCCESS) || (sendreq->data_storage == NULL))
- {
- /* We encountered an error (probably a timeout,
- * suggesting the DNS server we're talking to is
- * probably unreachable, wedged, or severely
- * overloaded) or we couldn't copy the request, so
- * mark the connection as broken. When we get to
- * process_broken_connections() we'll close the
- * connection and try to re-send requests to another
- * server.
- */
- server->is_broken = 1;
- /* Just to be paranoid, zero out this sendreq... */
- sendreq->data = NULL;
- sendreq->len = 0;
- }
- }
- }
-
- /* Invoke the callback */
- query->callback(query->arg, status, query->timeouts, abuf, alen);
- ares__free_query(query);
-
- /* Simple cleanup policy: if no queries are remaining, close all
- * network sockets unless STAYOPEN is set.
- */
- if (!(channel->flags & ARES_FLAG_STAYOPEN) &&
- ares__is_list_empty(&(channel->all_queries)))
- {
- for (i = 0; i < channel->nservers; i++)
- ares__close_sockets(channel, &channel->servers[i]);
- }
-}
-
-void ares__free_query(struct query *query)
-{
- /* Remove the query from all the lists in which it is linked */
- ares__remove_from_list(&(query->queries_by_qid));
- ares__remove_from_list(&(query->queries_by_timeout));
- ares__remove_from_list(&(query->queries_to_server));
- ares__remove_from_list(&(query->all_queries));
- /* Zero out some important stuff, to help catch bugs */
- query->callback = NULL;
- query->arg = NULL;
- /* Deallocate the memory associated with the query */
- free(query->tcpbuf);
- free(query->server_info);
- free(query);
-}