[164] | 1 | /**
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| 2 | * @file
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| 3 | * API functions for name resolving
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| 4 | *
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| 5 | */
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| 6 |
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| 7 | /*
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| 8 | * Redistribution and use in source and binary forms, with or without modification,
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| 9 | * are permitted provided that the following conditions are met:
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| 10 | *
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| 11 | * 1. Redistributions of source code must retain the above copyright notice,
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| 12 | * this list of conditions and the following disclaimer.
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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| 14 | * this list of conditions and the following disclaimer in the documentation
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| 15 | * and/or other materials provided with the distribution.
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| 16 | * 3. The name of the author may not be used to endorse or promote products
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| 17 | * derived from this software without specific prior written permission.
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| 18 | *
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| 19 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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| 20 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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| 21 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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| 22 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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| 23 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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| 24 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 25 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 26 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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| 27 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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| 28 | * OF SUCH DAMAGE.
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| 29 | *
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| 30 | * This file is part of the lwIP TCP/IP stack.
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| 31 | *
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| 32 | * Author: Simon Goldschmidt
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| 33 | *
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| 34 | */
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| 35 |
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| 36 | #include "lwip/netdb.h"
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| 37 |
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| 38 | #if LWIP_DNS && LWIP_SOCKET
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| 39 |
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| 40 | #include "lwip/err.h"
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| 41 | #include "lwip/mem.h"
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| 42 | #include "lwip/memp.h"
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| 43 | #include "lwip/ip_addr.h"
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| 44 | #include "lwip/api.h"
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| 45 | #include "lwip/dns.h"
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| 46 |
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| 47 | #include <string.h>
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| 48 | #include <stdlib.h>
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| 49 |
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| 50 | /** helper struct for gethostbyname_r to access the char* buffer */
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| 51 | struct gethostbyname_r_helper {
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| 52 | ip_addr_t *addr_list[2];
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| 53 | ip_addr_t addr;
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| 54 | char *aliases;
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| 55 | };
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| 56 |
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| 57 | /** h_errno is exported in netdb.h for access by applications. */
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| 58 | #if LWIP_DNS_API_DECLARE_H_ERRNO
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| 59 | int h_errno;
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| 60 | #endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
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| 61 |
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| 62 | /** define "hostent" variables storage: 0 if we use a static (but unprotected)
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| 63 | * set of variables for lwip_gethostbyname, 1 if we use a local storage */
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| 64 | #ifndef LWIP_DNS_API_HOSTENT_STORAGE
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| 65 | #define LWIP_DNS_API_HOSTENT_STORAGE 0
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| 66 | #endif
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| 67 |
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| 68 | /** define "hostent" variables storage */
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| 69 | #if LWIP_DNS_API_HOSTENT_STORAGE
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| 70 | #define HOSTENT_STORAGE
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| 71 | #else
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| 72 | #define HOSTENT_STORAGE static
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| 73 | #endif /* LWIP_DNS_API_STATIC_HOSTENT */
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| 74 |
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| 75 | /**
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| 76 | * Returns an entry containing addresses of address family AF_INET
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| 77 | * for the host with name name.
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| 78 | * Due to dns_gethostbyname limitations, only one address is returned.
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| 79 | *
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| 80 | * @param name the hostname to resolve
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| 81 | * @return an entry containing addresses of address family AF_INET
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| 82 | * for the host with name name
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| 83 | */
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| 84 | struct hostent*
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| 85 | lwip_gethostbyname(const char *name)
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| 86 | {
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| 87 | err_t err;
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| 88 | ip_addr_t addr;
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| 89 |
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| 90 | /* buffer variables for lwip_gethostbyname() */
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| 91 | HOSTENT_STORAGE struct hostent s_hostent;
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| 92 | HOSTENT_STORAGE char *s_aliases;
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| 93 | HOSTENT_STORAGE ip_addr_t s_hostent_addr;
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| 94 | HOSTENT_STORAGE ip_addr_t *s_phostent_addr[2];
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| 95 |
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| 96 | /* query host IP address */
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| 97 | err = netconn_gethostbyname(name, &addr);
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| 98 | if (err != ERR_OK) {
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| 99 | LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
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| 100 | h_errno = HOST_NOT_FOUND;
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| 101 | return NULL;
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| 102 | }
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| 103 |
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| 104 | /* fill hostent */
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| 105 | s_hostent_addr = addr;
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| 106 | s_phostent_addr[0] = &s_hostent_addr;
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| 107 | s_phostent_addr[1] = NULL;
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| 108 | s_hostent.h_name = (char*)name;
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| 109 | s_hostent.h_aliases = &s_aliases;
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| 110 | s_hostent.h_addrtype = AF_INET;
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| 111 | s_hostent.h_length = sizeof(ip_addr_t);
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| 112 | s_hostent.h_addr_list = (char**)&s_phostent_addr;
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| 113 |
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| 114 | #if DNS_DEBUG
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| 115 | /* dump hostent */
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| 116 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name == %s\n", s_hostent.h_name));
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| 117 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases == %p\n", s_hostent.h_aliases));
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| 118 | if (s_hostent.h_aliases != NULL) {
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| 119 | u8_t idx;
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| 120 | for ( idx=0; s_hostent.h_aliases[idx]; idx++) {
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| 121 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %p\n", idx, s_hostent.h_aliases[idx]));
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| 122 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %s\n", idx, s_hostent.h_aliases[idx]));
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| 123 | }
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| 124 | }
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| 125 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype == %d\n", s_hostent.h_addrtype));
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| 126 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length == %d\n", s_hostent.h_length));
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| 127 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list == %p\n", s_hostent.h_addr_list));
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| 128 | if (s_hostent.h_addr_list != NULL) {
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| 129 | u8_t idx;
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| 130 | for ( idx=0; s_hostent.h_addr_list[idx]; idx++) {
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| 131 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i] == %p\n", idx, s_hostent.h_addr_list[idx]));
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| 132 | LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n", idx, ip_ntoa((ip_addr_t*)s_hostent.h_addr_list[idx])));
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| 133 | }
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| 134 | }
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| 135 | #endif /* DNS_DEBUG */
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| 136 |
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| 137 | #if LWIP_DNS_API_HOSTENT_STORAGE
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| 138 | /* this function should return the "per-thread" hostent after copy from s_hostent */
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| 139 | return sys_thread_hostent(&s_hostent);
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| 140 | #else
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| 141 | return &s_hostent;
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| 142 | #endif /* LWIP_DNS_API_HOSTENT_STORAGE */
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| 143 | }
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| 144 |
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| 145 | /**
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| 146 | * Thread-safe variant of lwip_gethostbyname: instead of using a static
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| 147 | * buffer, this function takes buffer and errno pointers as arguments
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| 148 | * and uses these for the result.
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| 149 | *
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| 150 | * @param name the hostname to resolve
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| 151 | * @param ret pre-allocated struct where to store the result
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| 152 | * @param buf pre-allocated buffer where to store additional data
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| 153 | * @param buflen the size of buf
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| 154 | * @param result pointer to a hostent pointer that is set to ret on success
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| 155 | * and set to zero on error
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| 156 | * @param h_errnop pointer to an int where to store errors (instead of modifying
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| 157 | * the global h_errno)
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| 158 | * @return 0 on success, non-zero on error, additional error information
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| 159 | * is stored in *h_errnop instead of h_errno to be thread-safe
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| 160 | */
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| 161 | int
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| 162 | lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
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| 163 | size_t buflen, struct hostent **result, int *h_errnop)
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| 164 | {
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| 165 | err_t err;
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| 166 | struct gethostbyname_r_helper *h;
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| 167 | char *hostname;
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| 168 | size_t namelen;
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| 169 | int lh_errno;
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| 170 |
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| 171 | if (h_errnop == NULL) {
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| 172 | /* ensure h_errnop is never NULL */
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| 173 | h_errnop = &lh_errno;
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| 174 | }
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| 175 |
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| 176 | if (result == NULL) {
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| 177 | /* not all arguments given */
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| 178 | *h_errnop = EINVAL;
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| 179 | return -1;
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| 180 | }
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| 181 | /* first thing to do: set *result to nothing */
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| 182 | *result = NULL;
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| 183 | if ((name == NULL) || (ret == NULL) || (buf == NULL)) {
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| 184 | /* not all arguments given */
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| 185 | *h_errnop = EINVAL;
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| 186 | return -1;
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| 187 | }
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| 188 |
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| 189 | namelen = strlen(name);
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| 190 | if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) {
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| 191 | /* buf can't hold the data needed + a copy of name */
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| 192 | *h_errnop = ERANGE;
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| 193 | return -1;
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| 194 | }
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| 195 |
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| 196 | h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
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| 197 | hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
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| 198 |
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| 199 | /* query host IP address */
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| 200 | err = netconn_gethostbyname(name, &h->addr);
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| 201 | if (err != ERR_OK) {
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| 202 | LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
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| 203 | *h_errnop = HOST_NOT_FOUND;
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| 204 | return -1;
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| 205 | }
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| 206 |
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| 207 | /* copy the hostname into buf */
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| 208 | MEMCPY(hostname, name, namelen);
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| 209 | hostname[namelen] = 0;
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| 210 |
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| 211 | /* fill hostent */
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| 212 | h->addr_list[0] = &h->addr;
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| 213 | h->addr_list[1] = NULL;
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| 214 | h->aliases = NULL;
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| 215 | ret->h_name = hostname;
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| 216 | ret->h_aliases = &h->aliases;
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| 217 | ret->h_addrtype = AF_INET;
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| 218 | ret->h_length = sizeof(ip_addr_t);
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| 219 | ret->h_addr_list = (char**)&h->addr_list;
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| 220 |
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| 221 | /* set result != NULL */
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| 222 | *result = ret;
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| 223 |
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| 224 | /* return success */
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| 225 | return 0;
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| 226 | }
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| 227 |
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| 228 | /**
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| 229 | * Frees one or more addrinfo structures returned by getaddrinfo(), along with
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| 230 | * any additional storage associated with those structures. If the ai_next field
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| 231 | * of the structure is not null, the entire list of structures is freed.
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| 232 | *
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| 233 | * @param ai struct addrinfo to free
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| 234 | */
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| 235 | void
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| 236 | lwip_freeaddrinfo(struct addrinfo *ai)
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| 237 | {
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| 238 | struct addrinfo *next;
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| 239 |
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| 240 | while (ai != NULL) {
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| 241 | next = ai->ai_next;
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| 242 | memp_free(MEMP_NETDB, ai);
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| 243 | ai = next;
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| 244 | }
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| 245 | }
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| 246 |
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| 247 | /**
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| 248 | * Translates the name of a service location (for example, a host name) and/or
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| 249 | * a service name and returns a set of socket addresses and associated
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| 250 | * information to be used in creating a socket with which to address the
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| 251 | * specified service.
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| 252 | * Memory for the result is allocated internally and must be freed by calling
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| 253 | * lwip_freeaddrinfo()!
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| 254 | *
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| 255 | * Due to a limitation in dns_gethostbyname, only the first address of a
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| 256 | * host is returned.
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| 257 | * Also, service names are not supported (only port numbers)!
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| 258 | *
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| 259 | * @param nodename descriptive name or address string of the host
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| 260 | * (may be NULL -> local address)
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| 261 | * @param servname port number as string of NULL
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| 262 | * @param hints structure containing input values that set socktype and protocol
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| 263 | * @param res pointer to a pointer where to store the result (set to NULL on failure)
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| 264 | * @return 0 on success, non-zero on failure
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| 265 | */
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| 266 | int
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| 267 | lwip_getaddrinfo(const char *nodename, const char *servname,
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| 268 | const struct addrinfo *hints, struct addrinfo **res)
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| 269 | {
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| 270 | err_t err;
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| 271 | ip_addr_t addr;
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| 272 | struct addrinfo *ai;
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| 273 | struct sockaddr_in *sa = NULL;
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| 274 | int port_nr = 0;
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| 275 | size_t total_size;
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| 276 | size_t namelen = 0;
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| 277 |
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| 278 | if (res == NULL) {
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| 279 | return EAI_FAIL;
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| 280 | }
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| 281 | *res = NULL;
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| 282 | if ((nodename == NULL) && (servname == NULL)) {
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| 283 | return EAI_NONAME;
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| 284 | }
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| 285 |
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| 286 | if (servname != NULL) {
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| 287 | /* service name specified: convert to port number
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| 288 | * @todo?: currently, only ASCII integers (port numbers) are supported! */
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| 289 | port_nr = atoi(servname);
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| 290 | if ((port_nr <= 0) || (port_nr > 0xffff)) {
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| 291 | return EAI_SERVICE;
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| 292 | }
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| 293 | }
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| 294 |
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| 295 | if (nodename != NULL) {
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| 296 | /* service location specified, try to resolve */
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| 297 | err = netconn_gethostbyname(nodename, &addr);
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| 298 | if (err != ERR_OK) {
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| 299 | return EAI_FAIL;
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| 300 | }
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| 301 | } else {
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| 302 | /* service location specified, use loopback address */
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| 303 | ip_addr_set_loopback(&addr);
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| 304 | }
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| 305 |
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| 306 | total_size = sizeof(struct addrinfo) + sizeof(struct sockaddr_in);
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| 307 | if (nodename != NULL) {
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| 308 | namelen = strlen(nodename);
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| 309 | LWIP_ASSERT("namelen is too long", (namelen + 1) <= (mem_size_t)-1);
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| 310 | total_size += namelen + 1;
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| 311 | }
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| 312 | /* If this fails, please report to lwip-devel! :-) */
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| 313 | LWIP_ASSERT("total_size <= NETDB_ELEM_SIZE: please report this!",
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| 314 | total_size <= NETDB_ELEM_SIZE);
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| 315 | ai = (struct addrinfo *)memp_malloc(MEMP_NETDB);
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| 316 | if (ai == NULL) {
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| 317 | goto memerr;
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| 318 | }
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| 319 | memset(ai, 0, total_size);
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| 320 | sa = (struct sockaddr_in*)((u8_t*)ai + sizeof(struct addrinfo));
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| 321 | /* set up sockaddr */
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| 322 | inet_addr_from_ipaddr(&sa->sin_addr, &addr);
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| 323 | sa->sin_family = AF_INET;
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| 324 | sa->sin_len = sizeof(struct sockaddr_in);
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| 325 | sa->sin_port = htons((u16_t)port_nr);
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| 326 |
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| 327 | /* set up addrinfo */
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| 328 | ai->ai_family = AF_INET;
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| 329 | if (hints != NULL) {
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| 330 | /* copy socktype & protocol from hints if specified */
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| 331 | ai->ai_socktype = hints->ai_socktype;
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| 332 | ai->ai_protocol = hints->ai_protocol;
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| 333 | }
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| 334 | if (nodename != NULL) {
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| 335 | /* copy nodename to canonname if specified */
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| 336 | ai->ai_canonname = ((char*)ai + sizeof(struct addrinfo) + sizeof(struct sockaddr_in));
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| 337 | MEMCPY(ai->ai_canonname, nodename, namelen);
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| 338 | ai->ai_canonname[namelen] = 0;
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| 339 | }
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| 340 | ai->ai_addrlen = sizeof(struct sockaddr_in);
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| 341 | ai->ai_addr = (struct sockaddr*)sa;
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| 342 |
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| 343 | *res = ai;
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| 344 |
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| 345 | return 0;
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| 346 | memerr:
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| 347 | if (ai != NULL) {
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| 348 | memp_free(MEMP_NETDB, ai);
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| 349 | }
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| 350 | return EAI_MEMORY;
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| 351 | }
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| 352 |
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| 353 | #endif /* LWIP_DNS && LWIP_SOCKET */
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