2 /* Copyright 1998 by the Massachusetts Institute of Technology.
4 * Permission to use, copy, modify, and distribute this
5 * software and its documentation for any purpose and without
6 * fee is hereby granted, provided that the above copyright
7 * notice appear in all copies and that both that copyright
8 * notice and this permission notice appear in supporting
9 * documentation, and that the name of M.I.T. not be used in
10 * advertising or publicity pertaining to distribution of the
11 * software without specific, written prior permission.
12 * M.I.T. makes no representations about the suitability of
13 * this software for any purpose. It is provided "as is"
14 * without express or implied warranty.
17 #include "ares_setup.h"
19 #ifdef HAVE_SYS_SOCKET_H
20 # include <sys/socket.h>
22 #ifdef HAVE_NETINET_IN_H
23 # include <netinet/in.h>
25 #ifdef HAVE_ARPA_NAMESER_H
26 # include <arpa/nameser.h>
30 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
31 # include <arpa/nameser_compat.h>
37 #include "ares_private.h"
40 ares_callback callback;
44 static void qcallback(void *arg, int status, int timeouts, unsigned char *abuf, int alen);
46 void ares__rc4(rc4_key* key, unsigned char *buffer_ptr, int buffer_len)
51 unsigned char xorIndex;
57 state = &key->state[0];
58 for(counter = 0; counter < buffer_len; counter ++)
60 x = (unsigned char)((x + 1) % 256);
61 y = (unsigned char)((state[x] + y) % 256);
62 ARES_SWAP_BYTE(&state[x], &state[y]);
64 xorIndex = (unsigned char)((state[x] + state[y]) % 256);
66 buffer_ptr[counter] = (unsigned char)(buffer_ptr[counter]^state[xorIndex]);
72 static struct query* find_query_by_id(ares_channel channel, unsigned short id)
75 struct list_node* list_head;
76 struct list_node* list_node;
77 DNS_HEADER_SET_QID(((unsigned char*)&qid), id);
79 /* Find the query corresponding to this packet. */
80 list_head = &(channel->queries_by_qid[qid % ARES_QID_TABLE_SIZE]);
81 for (list_node = list_head->next; list_node != list_head;
82 list_node = list_node->next)
84 struct query *q = list_node->data;
92 /* a unique query id is generated using an rc4 key. Since the id may already
93 be used by a running query (as infrequent as it may be), a lookup is
94 performed per id generation. In practice this search should happen only
95 once per newly generated id
97 static unsigned short generate_unique_id(ares_channel channel)
102 id = ares__generate_new_id(&channel->id_key);
103 } while (find_query_by_id(channel, id));
105 return (unsigned short)id;
108 void ares_query(ares_channel channel, const char *name, int dnsclass,
109 int type, ares_callback callback, void *arg)
111 struct qquery *qquery;
113 int qlen, rd, status;
115 /* Compose the query. */
116 rd = !(channel->flags & ARES_FLAG_NORECURSE);
117 status = ares_mkquery(name, dnsclass, type, channel->next_id, rd, &qbuf,
119 if (status != ARES_SUCCESS)
121 if (qbuf != NULL) free(qbuf);
122 callback(arg, status, 0, NULL, 0);
126 channel->next_id = generate_unique_id(channel);
128 /* Allocate and fill in the query structure. */
129 qquery = malloc(sizeof(struct qquery));
132 ares_free_string(qbuf);
133 callback(arg, ARES_ENOMEM, 0, NULL, 0);
136 qquery->callback = callback;
139 /* Send it off. qcallback will be called when we get an answer. */
140 ares_send(channel, qbuf, qlen, qcallback, qquery);
141 ares_free_string(qbuf);
144 static void qcallback(void *arg, int status, int timeouts, unsigned char *abuf, int alen)
146 struct qquery *qquery = (struct qquery *) arg;
147 unsigned int ancount;
150 if (status != ARES_SUCCESS)
151 qquery->callback(qquery->arg, status, timeouts, abuf, alen);
154 /* Pull the response code and answer count from the packet. */
155 rcode = DNS_HEADER_RCODE(abuf);
156 ancount = DNS_HEADER_ANCOUNT(abuf);
158 /* Convert errors. */
162 status = (ancount > 0) ? ARES_SUCCESS : ARES_ENODATA;
165 status = ARES_EFORMERR;
168 status = ARES_ESERVFAIL;
171 status = ARES_ENOTFOUND;
174 status = ARES_ENOTIMP;
177 status = ARES_EREFUSED;
180 qquery->callback(qquery->arg, status, timeouts, abuf, alen);