Gilad Arnold | 968bf19 | 2015-07-17 00:23:30 -0700 | [diff] [blame] | 1 | |
| 2 | /* Copyright 1998 by the Massachusetts Institute of Technology. |
| 3 | * |
| 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. |
| 15 | */ |
| 16 | |
| 17 | #include "ares_setup.h" |
| 18 | |
| 19 | #ifdef HAVE_SYS_SOCKET_H |
| 20 | # include <sys/socket.h> |
| 21 | #endif |
| 22 | #ifdef HAVE_NETINET_IN_H |
| 23 | # include <netinet/in.h> |
| 24 | #endif |
| 25 | #ifdef HAVE_ARPA_NAMESER_H |
| 26 | # include <arpa/nameser.h> |
| 27 | #else |
| 28 | # include "nameser.h" |
| 29 | #endif |
| 30 | #ifdef HAVE_ARPA_NAMESER_COMPAT_H |
| 31 | # include <arpa/nameser_compat.h> |
| 32 | #endif |
| 33 | |
| 34 | #include <stdlib.h> |
| 35 | #include "ares.h" |
| 36 | #include "ares_dns.h" |
| 37 | #include "ares_private.h" |
| 38 | |
| 39 | struct qquery { |
| 40 | ares_callback callback; |
| 41 | void *arg; |
| 42 | }; |
| 43 | |
| 44 | static void qcallback(void *arg, int status, int timeouts, unsigned char *abuf, int alen); |
| 45 | |
| 46 | void ares__rc4(rc4_key* key, unsigned char *buffer_ptr, int buffer_len) |
| 47 | { |
| 48 | unsigned char x; |
| 49 | unsigned char y; |
| 50 | unsigned char* state; |
| 51 | unsigned char xorIndex; |
| 52 | short counter; |
| 53 | |
| 54 | x = key->x; |
| 55 | y = key->y; |
| 56 | |
| 57 | state = &key->state[0]; |
| 58 | for(counter = 0; counter < buffer_len; counter ++) |
| 59 | { |
| 60 | x = (unsigned char)((x + 1) % 256); |
| 61 | y = (unsigned char)((state[x] + y) % 256); |
| 62 | ARES_SWAP_BYTE(&state[x], &state[y]); |
| 63 | |
| 64 | xorIndex = (unsigned char)((state[x] + state[y]) % 256); |
| 65 | |
| 66 | buffer_ptr[counter] = (unsigned char)(buffer_ptr[counter]^state[xorIndex]); |
| 67 | } |
| 68 | key->x = x; |
| 69 | key->y = y; |
| 70 | } |
| 71 | |
| 72 | static struct query* find_query_by_id(ares_channel channel, unsigned short id) |
| 73 | { |
| 74 | unsigned short qid; |
| 75 | struct list_node* list_head; |
| 76 | struct list_node* list_node; |
| 77 | DNS_HEADER_SET_QID(((unsigned char*)&qid), id); |
| 78 | |
| 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) |
| 83 | { |
| 84 | struct query *q = list_node->data; |
| 85 | if (q->qid == qid) |
| 86 | return q; |
| 87 | } |
| 88 | return NULL; |
| 89 | } |
| 90 | |
| 91 | |
| 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 |
| 96 | */ |
| 97 | static unsigned short generate_unique_id(ares_channel channel) |
| 98 | { |
| 99 | unsigned short id; |
| 100 | |
| 101 | do { |
| 102 | id = ares__generate_new_id(&channel->id_key); |
| 103 | } while (find_query_by_id(channel, id)); |
| 104 | |
| 105 | return (unsigned short)id; |
| 106 | } |
| 107 | |
| 108 | void ares_query(ares_channel channel, const char *name, int dnsclass, |
| 109 | int type, ares_callback callback, void *arg) |
| 110 | { |
| 111 | struct qquery *qquery; |
| 112 | unsigned char *qbuf; |
| 113 | int qlen, rd, status; |
| 114 | |
| 115 | /* Compose the query. */ |
| 116 | rd = !(channel->flags & ARES_FLAG_NORECURSE); |
| 117 | status = ares_mkquery(name, dnsclass, type, channel->next_id, rd, &qbuf, |
| 118 | &qlen); |
| 119 | if (status != ARES_SUCCESS) |
| 120 | { |
| 121 | if (qbuf != NULL) free(qbuf); |
| 122 | callback(arg, status, 0, NULL, 0); |
| 123 | return; |
| 124 | } |
| 125 | |
| 126 | channel->next_id = generate_unique_id(channel); |
| 127 | |
| 128 | /* Allocate and fill in the query structure. */ |
| 129 | qquery = malloc(sizeof(struct qquery)); |
| 130 | if (!qquery) |
| 131 | { |
| 132 | ares_free_string(qbuf); |
| 133 | callback(arg, ARES_ENOMEM, 0, NULL, 0); |
| 134 | return; |
| 135 | } |
| 136 | qquery->callback = callback; |
| 137 | qquery->arg = arg; |
| 138 | |
| 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); |
| 142 | } |
| 143 | |
| 144 | static void qcallback(void *arg, int status, int timeouts, unsigned char *abuf, int alen) |
| 145 | { |
| 146 | struct qquery *qquery = (struct qquery *) arg; |
| 147 | unsigned int ancount; |
| 148 | int rcode; |
| 149 | |
| 150 | if (status != ARES_SUCCESS) |
| 151 | qquery->callback(qquery->arg, status, timeouts, abuf, alen); |
| 152 | else |
| 153 | { |
| 154 | /* Pull the response code and answer count from the packet. */ |
| 155 | rcode = DNS_HEADER_RCODE(abuf); |
| 156 | ancount = DNS_HEADER_ANCOUNT(abuf); |
| 157 | |
| 158 | /* Convert errors. */ |
| 159 | switch (rcode) |
| 160 | { |
| 161 | case NOERROR: |
| 162 | status = (ancount > 0) ? ARES_SUCCESS : ARES_ENODATA; |
| 163 | break; |
| 164 | case FORMERR: |
| 165 | status = ARES_EFORMERR; |
| 166 | break; |
| 167 | case SERVFAIL: |
| 168 | status = ARES_ESERVFAIL; |
| 169 | break; |
| 170 | case NXDOMAIN: |
| 171 | status = ARES_ENOTFOUND; |
| 172 | break; |
| 173 | case NOTIMP: |
| 174 | status = ARES_ENOTIMP; |
| 175 | break; |
| 176 | case REFUSED: |
| 177 | status = ARES_EREFUSED; |
| 178 | break; |
| 179 | } |
| 180 | qquery->callback(qquery->arg, status, timeouts, abuf, alen); |
| 181 | } |
| 182 | free(qquery); |
| 183 | } |