1968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 2968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold/* Copyright 1998 by the Massachusetts Institute of Technology. 3968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * 4968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * Permission to use, copy, modify, and distribute this 5968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * software and its documentation for any purpose and without 6968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * fee is hereby granted, provided that the above copyright 7968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * notice appear in all copies and that both that copyright 8968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * notice and this permission notice appear in supporting 9968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * documentation, and that the name of M.I.T. not be used in 10968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * advertising or publicity pertaining to distribution of the 11968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * software without specific, written prior permission. 12968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * M.I.T. makes no representations about the suitability of 13968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * this software for any purpose. It is provided "as is" 14968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * without express or implied warranty. 15968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold */ 16968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 17968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#include "ares_setup.h" 18968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 19968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#ifdef HAVE_SYS_SOCKET_H 20968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold# include <sys/socket.h> 21968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#endif 22968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#ifdef HAVE_NETINET_IN_H 23968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold# include <netinet/in.h> 24968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#endif 25968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#ifdef HAVE_ARPA_NAMESER_H 26968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold# include <arpa/nameser.h> 27968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#else 28968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold# include "nameser.h" 29968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#endif 30968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#ifdef HAVE_ARPA_NAMESER_COMPAT_H 31968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold# include <arpa/nameser_compat.h> 32968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#endif 33968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 34968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#include <stdlib.h> 35968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#include <string.h> 36968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#include <time.h> 37968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#include "ares.h" 38968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#include "ares_dns.h" 39968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold#include "ares_private.h" 40968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 41968bf19396ad404e89420f5d67900fce13f4186cGilad Arnoldvoid ares_send(ares_channel channel, const unsigned char *qbuf, int qlen, 42968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares_callback callback, void *arg) 43968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold{ 44968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold struct query *query; 45968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold int i; 46968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold struct timeval now; 47968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 48968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Verify that the query is at least long enough to hold the header. */ 49968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold if (qlen < HFIXEDSZ || qlen >= (1 << 16)) 50968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold { 51968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold callback(arg, ARES_EBADQUERY, 0, NULL, 0); 52968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold return; 53968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold } 54968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 55968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Allocate space for query and allocated fields. */ 56968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query = malloc(sizeof(struct query)); 57968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold if (!query) 58968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold { 59968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold callback(arg, ARES_ENOMEM, 0, NULL, 0); 60968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold return; 61968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold } 62968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->tcpbuf = malloc(qlen + 2); 63968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold if (!query->tcpbuf) 64968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold { 65968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold free(query); 66968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold callback(arg, ARES_ENOMEM, 0, NULL, 0); 67968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold return; 68968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold } 69968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->server_info = malloc(channel->nservers * 70968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold sizeof(query->server_info[0])); 71968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold if (!query->server_info) 72968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold { 73968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold free(query->tcpbuf); 74968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold free(query); 75968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold callback(arg, ARES_ENOMEM, 0, NULL, 0); 76968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold return; 77968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold } 78968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 79968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Compute the query ID. Start with no timeout. */ 80968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->qid = (unsigned short)DNS_HEADER_QID(qbuf); 81968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->timeout.tv_sec = 0; 82968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->timeout.tv_usec = 0; 83968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 84968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Form the TCP query buffer by prepending qlen (as two 85968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * network-order bytes) to qbuf. 86968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold */ 87968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->tcpbuf[0] = (unsigned char)((qlen >> 8) & 0xff); 88968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->tcpbuf[1] = (unsigned char)(qlen & 0xff); 89968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold memcpy(query->tcpbuf + 2, qbuf, qlen); 90968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->tcplen = qlen + 2; 91968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 92968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Fill in query arguments. */ 93968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->qbuf = query->tcpbuf + 2; 94968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->qlen = qlen; 95968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->callback = callback; 96968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->arg = arg; 97968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 98968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Initialize query status. */ 99968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->try_count = 0; 100968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 101968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Choose the server to send the query to. If rotation is enabled, keep track 102968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * of the next server we want to use. */ 103968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->server = channel->last_server; 104968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold if (channel->rotate == 1) 105968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold channel->last_server = (channel->last_server + 1) % channel->nservers; 106968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 107968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold for (i = 0; i < channel->nservers; i++) 108968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold { 109968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->server_info[i].skip_server = 0; 110968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->server_info[i].tcp_connection_generation = 0; 111968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold } 112968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->using_tcp = (channel->flags & ARES_FLAG_USEVC) || qlen > PACKETSZ; 113968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->error_status = ARES_ECONNREFUSED; 114968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold query->timeouts = 0; 115968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 116968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Initialize our list nodes. */ 117968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares__init_list_node(&(query->queries_by_qid), query); 118968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares__init_list_node(&(query->queries_by_timeout), query); 119968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares__init_list_node(&(query->queries_to_server), query); 120968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares__init_list_node(&(query->all_queries), query); 121968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 122968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Chain the query into the list of all queries. */ 123968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares__insert_in_list(&(query->all_queries), &(channel->all_queries)); 124968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Keep track of queries bucketed by qid, so we can process DNS 125968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold * responses quickly. 126968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold */ 127968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares__insert_in_list( 128968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold &(query->queries_by_qid), 129968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold &(channel->queries_by_qid[query->qid % ARES_QID_TABLE_SIZE])); 130968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold 131968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold /* Perform the first query action. */ 132968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold now = ares__tvnow(); 133968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold ares__send_query(channel, query, &now); 134968bf19396ad404e89420f5d67900fce13f4186cGilad Arnold} 135