diff options
Diffstat (limited to 'deps/node/deps/cares/src/ares_process.c')
| -rw-r--r-- | deps/node/deps/cares/src/ares_process.c | 1473 |
1 files changed, 0 insertions, 1473 deletions
diff --git a/deps/node/deps/cares/src/ares_process.c b/deps/node/deps/cares/src/ares_process.c deleted file mode 100644 index df9f290b..00000000 --- a/deps/node/deps/cares/src/ares_process.c +++ /dev/null @@ -1,1473 +0,0 @@ - -/* Copyright 1998 by the Massachusetts Institute of Technology. - * Copyright (C) 2004-2017 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_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_INET_H -# include <arpa/inet.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_STRINGS_H -# include <strings.h> -#endif -#ifdef HAVE_SYS_IOCTL_H -# include <sys/ioctl.h> -#endif -#ifdef NETWARE -# include <sys/filio.h> -#endif - -#include <assert.h> -#include <fcntl.h> -#include <limits.h> - -#include "ares.h" -#include "ares_dns.h" -#include "ares_nowarn.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, - ares_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 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 int same_address(struct sockaddr *sa, struct ares_addr *aa); -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 */ -static void 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; - } -} - -/* - * generic process function - */ -static void processfds(ares_channel channel, - fd_set *read_fds, ares_socket_t read_fd, - fd_set *write_fds, ares_socket_t write_fd) -{ - struct timeval now = ares__tvnow(); - - write_tcp_data(channel, write_fds, write_fd, &now); - read_tcp_data(channel, read_fds, read_fd, &now); - read_udp_packets(channel, read_fds, read_fd, &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(ares_channel channel, fd_set *read_fds, fd_set *write_fds) -{ - processfds(channel, read_fds, ARES_SOCKET_BAD, write_fds, ARES_SOCKET_BAD); -} - -/* 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) -{ - processfds(channel, NULL, read_fd, NULL, write_fd); -} - - -/* 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; -} - -static ares_ssize_t socket_writev(ares_channel channel, ares_socket_t s, const struct iovec * vec, int len) -{ - if (channel->sock_funcs) - return channel->sock_funcs->asendv(s, vec, len, channel->sock_func_cb_data); - - return writev(s, vec, len); -} - -static ares_ssize_t socket_write(ares_channel channel, ares_socket_t s, const void * data, size_t len) -{ - if (channel->sock_funcs) - { - struct iovec vec; - vec.iov_base = (void*)data; - vec.iov_len = len; - return channel->sock_funcs->asendv(s, &vec, 1, channel->sock_func_cb_data); - } - return swrite(s, data, len); -} - -/* 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; - ares_ssize_t scount; - ares_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 = ares_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 = socket_writev(channel, server->tcp_socket, vec, (int)n); - ares_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 = socket_write(channel, 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, - ares_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 (sendreq->data_storage) - ares_free(sendreq->data_storage); - ares_free(sendreq); - if (server->qhead == NULL) { - SOCK_STATE_CALLBACK(channel, server->tcp_socket, 1, 0); - server->qtail = NULL; - - /* qhead is NULL so we cannot continue this loop */ - break; - } - } - else { - sendreq->data += num_bytes; - sendreq->len -= num_bytes; - num_bytes = 0; - } - } -} - -static ares_ssize_t socket_recvfrom(ares_channel channel, - ares_socket_t s, - void * data, - size_t data_len, - int flags, - struct sockaddr *from, - ares_socklen_t *from_len) -{ - if (channel->sock_funcs) - return channel->sock_funcs->arecvfrom(s, data, data_len, - flags, from, from_len, - channel->sock_func_cb_data); - -#ifdef HAVE_RECVFROM - return recvfrom(s, data, data_len, flags, from, from_len); -#else - return sread(s, data, data_len); -#endif -} - -static ares_ssize_t socket_recv(ares_channel channel, - ares_socket_t s, - void * data, - size_t data_len) -{ - if (channel->sock_funcs) - return channel->sock_funcs->arecvfrom(s, data, data_len, 0, 0, 0, - channel->sock_func_cb_data); - - return sread(s, data, data_len); -} - -/* 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; - ares_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 = socket_recv(channel, 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 = ares_malloc(server->tcp_length); - if (!server->tcp_buffer) { - handle_error(channel, i, now); - return; /* bail out on malloc failure. TODO: make this - function return error codes */ - } - server->tcp_buffer_pos = 0; - } - } - else - { - /* Read data into the allocated buffer. */ - count = socket_recv(channel, 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); - ares_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; - ares_ssize_t count; - unsigned char buf[MAXENDSSZ + 1]; -#ifdef HAVE_RECVFROM - ares_socklen_t fromlen; - union { - struct sockaddr sa; - struct sockaddr_in sa4; - struct sockaddr_in6 sa6; - } from; -#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 { - if (server->udp_socket == ARES_SOCKET_BAD) - count = 0; - - else { - if (server->addr.family == AF_INET) - fromlen = sizeof(from.sa4); - else - fromlen = sizeof(from.sa6); - count = socket_recvfrom(channel, server->udp_socket, (void *)buf, - sizeof(buf), 0, &from.sa, &fromlen); - } - - if (count == -1 && try_again(SOCKERRNO)) - continue; - else if (count <= 0) - handle_error(channel, i, now); -#ifdef HAVE_RECVFROM - else if (!same_address(&from.sa, &server->addr)) - /* The address the response comes from does 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, packetsz; - 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; - - packetsz = PACKETSZ; - /* If we use EDNS and server answers with one of these RCODES, the protocol - * extension is not understood by the responder. We must retry the query - * without EDNS enabled. - */ - if (channel->flags & ARES_FLAG_EDNS) - { - packetsz = channel->ednspsz; - if (rcode == NOTIMP || rcode == FORMERR || rcode == SERVFAIL) - { - int qlen = (query->tcplen - 2) - EDNSFIXEDSZ; - channel->flags ^= ARES_FLAG_EDNS; - query->tcplen -= EDNSFIXEDSZ; - query->qlen -= EDNSFIXEDSZ; - query->tcpbuf[0] = (unsigned char)((qlen >> 8) & 0xff); - query->tcpbuf[1] = (unsigned char)(qlen & 0xff); - DNS_HEADER_SET_ARCOUNT(query->tcpbuf + 2, 0); - query->tcpbuf = ares_realloc(query->tcpbuf, query->tcplen); - query->qbuf = query->tcpbuf + 2; - ares__send_query(channel, query, now); - 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); - } - } -} - -/* Swap the contents of two lists */ -static void swap_lists(struct list_node* head_a, - struct list_node* head_b) -{ - int is_a_empty = ares__is_list_empty(head_a); - int is_b_empty = ares__is_list_empty(head_b); - struct list_node old_a = *head_a; - struct list_node old_b = *head_b; - - if (is_a_empty) { - ares__init_list_head(head_b); - } else { - *head_b = old_a; - old_a.next->prev = head_b; - old_a.prev->next = head_b; - } - if (is_b_empty) { - ares__init_list_head(head_a); - } else { - *head_a = old_b; - old_b.next->prev = head_a; - old_b.prev->next = head_a; - } -} - -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); - 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_count) < (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 = ares_malloc(sizeof(struct send_request)); - if (!sendreq) - { - end_query(channel, query, ARES_ENOMEM, NULL, 0); - return; - } - memset(sendreq, 0, sizeof(struct send_request)); - /* 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 (socket_write(channel, 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; - } - } - - /* For each trip through the entire server list, double the channel's - * assigned timeout, avoiding overflow. If channel->timeout is negative, - * leave it as-is, even though that should be impossible here. - */ - timeplus = channel->timeout; - { - /* How many times do we want to double it? Presume sane values here. */ - const int shift = query->try_count / channel->nservers; - - /* Is there enough room to shift timeplus left that many times? - * - * To find out, confirm that all of the bits we'll shift away are zero. - * Stop considering a shift if we get to the point where we could shift - * a 1 into the sign bit (i.e. when shift is within two of the bit - * count). - * - * This has the side benefit of leaving negative numbers unchanged. - */ - if(shift <= (int)(sizeof(int) * CHAR_BIT - 1) - && (timeplus >> (sizeof(int) * CHAR_BIT - 1 - shift)) == 0) - { - timeplus <<= shift; - } - } - - query->timeout = *now; - 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)); /* LCOV_EXCL_LINE */ - -#elif defined(HAVE_IOCTL_FIONBIO) - - /* older unix versions */ - int flags = nonblock ? 1 : 0; - return ioctl(sockfd, FIONBIO, &flags); - -#elif defined(HAVE_IOCTLSOCKET_FIONBIO) - -#ifdef WATT32 - char flags = nonblock ? 1 : 0; -#else - /* Windows */ - unsigned long flags = nonblock ? 1UL : 0UL; -#endif - return ioctlsocket(sockfd, FIONBIO, &flags); - -#elif defined(HAVE_IOCTLSOCKET_CAMEL_FIONBIO) - - /* Amiga */ - long flags = nonblock ? 1L : 0L; - return IoctlSocket(sockfd, FIONBIO, flags); - -#elif defined(HAVE_SETSOCKOPT_SO_NONBLOCK) - - /* BeOS */ - long b = nonblock ? 1L : 0L; - 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(ares_socket_t s, int family, ares_channel channel) -{ - union { - struct sockaddr sa; - struct sockaddr_in sa4; - struct sockaddr_in6 sa6; - } local; - - /* do not set options for user-managed sockets */ - if (channel->sock_funcs) - return 0; - - (void)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; /* LCOV_EXCL_LINE */ -#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; - -#ifdef SO_BINDTODEVICE - if (channel->local_dev_name[0]) { - if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE, - channel->local_dev_name, sizeof(channel->local_dev_name))) { - /* Only root can do this, and usually not fatal if it doesn't work, so */ - /* just continue on. */ - } - } -#endif - - if (family == AF_INET) { - if (channel->local_ip4) { - memset(&local.sa4, 0, sizeof(local.sa4)); - local.sa4.sin_family = AF_INET; - local.sa4.sin_addr.s_addr = htonl(channel->local_ip4); - if (bind(s, &local.sa, sizeof(local.sa4)) < 0) - return -1; - } - } - else if (family == AF_INET6) { - if (memcmp(channel->local_ip6, &ares_in6addr_any, - sizeof(channel->local_ip6)) != 0) { - memset(&local.sa6, 0, sizeof(local.sa6)); - local.sa6.sin6_family = AF_INET6; - memcpy(&local.sa6.sin6_addr, channel->local_ip6, - sizeof(channel->local_ip6)); - if (bind(s, &local.sa, sizeof(local.sa6)) < 0) - return -1; - } - } - - return 0; -} - -static ares_socket_t open_socket(ares_channel channel, int af, int type, int protocol) -{ - if (channel->sock_funcs != 0) - return channel->sock_funcs->asocket(af, - type, - protocol, - channel->sock_func_cb_data); - - return socket(af, type, protocol); -} - -static int connect_socket(ares_channel channel, ares_socket_t sockfd, - const struct sockaddr * addr, - ares_socklen_t addrlen) -{ - if (channel->sock_funcs != 0) - return channel->sock_funcs->aconnect(sockfd, - addr, - addrlen, - channel->sock_func_cb_data); - - return connect(sockfd, addr, addrlen); -} - -static int open_tcp_socket(ares_channel channel, struct server_state *server) -{ - ares_socket_t s; - int opt; - ares_socklen_t salen; - union { - struct sockaddr_in sa4; - struct sockaddr_in6 sa6; - } saddr; - struct sockaddr *sa; - - switch (server->addr.family) - { - case AF_INET: - sa = (void *)&saddr.sa4; - salen = sizeof(saddr.sa4); - memset(sa, 0, salen); - saddr.sa4.sin_family = AF_INET; - if (server->addr.tcp_port) { - saddr.sa4.sin_port = aresx_sitous(server->addr.tcp_port); - } else { - saddr.sa4.sin_port = aresx_sitous(channel->tcp_port); - } - memcpy(&saddr.sa4.sin_addr, &server->addr.addrV4, - sizeof(server->addr.addrV4)); - break; - case AF_INET6: - sa = (void *)&saddr.sa6; - salen = sizeof(saddr.sa6); - memset(sa, 0, salen); - saddr.sa6.sin6_family = AF_INET6; - if (server->addr.tcp_port) { - saddr.sa6.sin6_port = aresx_sitous(server->addr.tcp_port); - } else { - saddr.sa6.sin6_port = aresx_sitous(channel->tcp_port); - } - memcpy(&saddr.sa6.sin6_addr, &server->addr.addrV6, - sizeof(server->addr.addrV6)); - break; - default: - return -1; /* LCOV_EXCL_LINE */ - } - - /* Acquire a socket. */ - s = open_socket(channel, server->addr.family, SOCK_STREAM, 0); - if (s == ARES_SOCKET_BAD) - return -1; - - /* Configure it. */ - if (configure_socket(s, server->addr.family, channel) < 0) - { - ares__socket_close(channel, 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. - */ - opt = 1; - if (channel->sock_funcs == 0 - && - setsockopt(s, IPPROTO_TCP, TCP_NODELAY, - (void *)&opt, sizeof(opt)) == -1) - { - ares__socket_close(channel, s); - return -1; - } -#endif - - if (channel->sock_config_cb) - { - int err = channel->sock_config_cb(s, SOCK_STREAM, - channel->sock_config_cb_data); - if (err < 0) - { - ares__socket_close(channel, s); - return err; - } - } - - /* Connect to the server. */ - if (connect_socket(channel, s, sa, salen) == -1) - { - int err = SOCKERRNO; - - if (err != EINPROGRESS && err != EWOULDBLOCK) - { - ares__socket_close(channel, 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) - { - ares__socket_close(channel, 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; - ares_socklen_t salen; - union { - struct sockaddr_in sa4; - struct sockaddr_in6 sa6; - } saddr; - struct sockaddr *sa; - - switch (server->addr.family) - { - case AF_INET: - sa = (void *)&saddr.sa4; - salen = sizeof(saddr.sa4); - memset(sa, 0, salen); - saddr.sa4.sin_family = AF_INET; - if (server->addr.udp_port) { - saddr.sa4.sin_port = aresx_sitous(server->addr.udp_port); - } else { - saddr.sa4.sin_port = aresx_sitous(channel->udp_port); - } - memcpy(&saddr.sa4.sin_addr, &server->addr.addrV4, - sizeof(server->addr.addrV4)); - break; - case AF_INET6: - sa = (void *)&saddr.sa6; - salen = sizeof(saddr.sa6); - memset(sa, 0, salen); - saddr.sa6.sin6_family = AF_INET6; - if (server->addr.udp_port) { - saddr.sa6.sin6_port = aresx_sitous(server->addr.udp_port); - } else { - saddr.sa6.sin6_port = aresx_sitous(channel->udp_port); - } - memcpy(&saddr.sa6.sin6_addr, &server->addr.addrV6, - sizeof(server->addr.addrV6)); - break; - default: - return -1; /* LCOV_EXCL_LINE */ - } - - /* Acquire a socket. */ - s = open_socket(channel, server->addr.family, SOCK_DGRAM, 0); - if (s == ARES_SOCKET_BAD) - return -1; - - /* Set the socket non-blocking. */ - if (configure_socket(s, server->addr.family, channel) < 0) - { - ares__socket_close(channel, s); - return -1; - } - - if (channel->sock_config_cb) - { - int err = channel->sock_config_cb(s, SOCK_DGRAM, - channel->sock_config_cb_data); - if (err < 0) - { - ares__socket_close(channel, s); - return err; - } - } - - /* Connect to the server. */ - if (connect_socket(channel, s, sa, salen) == -1) - { - int err = SOCKERRNO; - - if (err != EINPROGRESS && err != EWOULDBLOCK) - { - ares__socket_close(channel, 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) - { - ares__socket_close(channel, 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) - { - ares_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) - { - ares_free(q.name); - return 0; - } - a.p += a.namelen; - if (a.p + QFIXEDSZ > abuf + alen) - { - ares_free(q.name); - ares_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) - { - ares_free(a.name); - break; - } - ares_free(a.name); - } - - ares_free(q.name); - if (j == a.qdcount) - return 0; - } - return 1; -} - -static int same_address(struct sockaddr *sa, struct ares_addr *aa) -{ - void *addr1; - void *addr2; - - if (sa->sa_family == aa->family) - { - switch (aa->family) - { - case AF_INET: - addr1 = &aa->addrV4; - addr2 = &((struct sockaddr_in *)sa)->sin_addr; - if (memcmp(addr1, addr2, sizeof(aa->addrV4)) == 0) - return 1; /* match */ - break; - case AF_INET6: - addr1 = &aa->addrV6; - addr2 = &((struct sockaddr_in6 *)sa)->sin6_addr; - if (memcmp(addr1, addr2, sizeof(aa->addrV6)) == 0) - return 1; /* match */ - break; - default: - break; /* LCOV_EXCL_LINE */ - } - } - return 0; /* different */ -} - -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 = ares_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 */ - ares_free(query->tcpbuf); - ares_free(query->server_info); - ares_free(query); -} - -void ares__socket_close(ares_channel channel, ares_socket_t s) -{ - if (channel->sock_funcs) - channel->sock_funcs->aclose(s, channel->sock_func_cb_data); - else - sclose(s); -} |