diff --git a/src/dns.c b/src/dns.c deleted file mode 100644 index 563a876..0000000 --- a/src/dns.c +++ /dev/null @@ -1,1648 +0,0 @@ -/** - * @file - * DNS - host name to IP address resolver. - * - * @defgroup dns DNS - * @ingroup callbackstyle_api - * - * Implements a DNS host name to IP address resolver. - * - * The lwIP DNS resolver functions are used to lookup a host name and - * map it to a numerical IP address. It maintains a list of resolved - * hostnames that can be queried with the dns_lookup() function. - * New hostnames can be resolved using the dns_query() function. - * - * The lwIP version of the resolver also adds a non-blocking version of - * gethostbyname() that will work with a raw API application. This function - * checks for an IP address string first and converts it if it is valid. - * gethostbyname() then does a dns_lookup() to see if the name is - * already in the table. If so, the IP is returned. If not, a query is - * issued and the function returns with a ERR_INPROGRESS status. The app - * using the dns client must then go into a waiting state. - * - * Once a hostname has been resolved (or found to be non-existent), - * the resolver code calls a specified callback function (which - * must be implemented by the module that uses the resolver). - * - * Multicast DNS queries are supported for names ending on ".local". - * However, only "One-Shot Multicast DNS Queries" are supported (RFC 6762 - * chapter 5.1), this is not a fully compliant implementation of continuous - * mDNS querying! - * - * All functions must be called from TCPIP thread. - * - * @see DNS_MAX_SERVERS - * @see LWIP_DHCP_MAX_DNS_SERVERS - * @see @ref netconn_common for thread-safe access. - */ - -/* - * Port to lwIP from uIP - * by Jim Pettinato April 2007 - * - * security fixes and more by Simon Goldschmidt - * - * uIP version Copyright (c) 2002-2003, Adam Dunkels. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. The name of the author may not be used to endorse or promote - * products derived from this software without specific prior - * written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS - * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED - * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY - * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE - * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS - * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, - * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -/*----------------------------------------------------------------------------- - * RFC 1035 - Domain names - implementation and specification - * RFC 2181 - Clarifications to the DNS Specification - *----------------------------------------------------------------------------*/ - -/** @todo: define good default values (rfc compliance) */ -/** @todo: improve answer parsing, more checkings... */ -/** @todo: check RFC1035 - 7.3. Processing responses */ -/** @todo: one-shot mDNS: dual-stack fallback to another IP version */ - -/*----------------------------------------------------------------------------- - * Includes - *----------------------------------------------------------------------------*/ - -#include "lwip/opt.h" - -#if LWIP_DNS /* don't build if not configured for use in lwipopts.h */ - -#include "lwip/def.h" -#include "lwip/udp.h" -#include "lwip/mem.h" -#include "lwip/memp.h" -#include "lwip/dns.h" -#include "lwip/prot/dns.h" - -#include - -/** Random generator function to create random TXIDs and source ports for queries */ -#ifndef DNS_RAND_TXID -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_XID) != 0) -#define DNS_RAND_TXID LWIP_RAND -#else -static u16_t dns_txid; -#define DNS_RAND_TXID() (++dns_txid) -#endif -#endif - -/** Limits the source port to be >= 1024 by default */ -#ifndef DNS_PORT_ALLOWED -#define DNS_PORT_ALLOWED(port) ((port) >= 1024) -#endif - -/** DNS resource record max. TTL (one week as default) */ -#ifndef DNS_MAX_TTL -#define DNS_MAX_TTL 604800 -#elif DNS_MAX_TTL > 0x7FFFFFFF -#error DNS_MAX_TTL must be a positive 32-bit value -#endif - -#if DNS_TABLE_SIZE > 255 -#error DNS_TABLE_SIZE must fit into an u8_t -#endif -#if DNS_MAX_SERVERS > 255 -#error DNS_MAX_SERVERS must fit into an u8_t -#endif - -/* The number of parallel requests (i.e. calls to dns_gethostbyname - * that cannot be answered from the DNS table. - * This is set to the table size by default. - */ -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0) -#ifndef DNS_MAX_REQUESTS -#define DNS_MAX_REQUESTS DNS_TABLE_SIZE -#else -#if DNS_MAX_REQUESTS > 255 -#error DNS_MAX_REQUESTS must fit into an u8_t -#endif -#endif -#else -/* In this configuration, both arrays have to have the same size and are used - * like one entry (used/free) */ -#define DNS_MAX_REQUESTS DNS_TABLE_SIZE -#endif - -/* The number of UDP source ports used in parallel */ -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) -#ifndef DNS_MAX_SOURCE_PORTS -#define DNS_MAX_SOURCE_PORTS DNS_MAX_REQUESTS -#else -#if DNS_MAX_SOURCE_PORTS > 255 -#error DNS_MAX_SOURCE_PORTS must fit into an u8_t -#endif -#endif -#else -#ifdef DNS_MAX_SOURCE_PORTS -#undef DNS_MAX_SOURCE_PORTS -#endif -#define DNS_MAX_SOURCE_PORTS 1 -#endif - -#if LWIP_IPV4 && LWIP_IPV6 -#define LWIP_DNS_ADDRTYPE_IS_IPV6(t) (((t) == LWIP_DNS_ADDRTYPE_IPV6_IPV4) || ((t) == LWIP_DNS_ADDRTYPE_IPV6)) -#define LWIP_DNS_ADDRTYPE_MATCH_IP(t, ip) (IP_IS_V6_VAL(ip) ? LWIP_DNS_ADDRTYPE_IS_IPV6(t) : (!LWIP_DNS_ADDRTYPE_IS_IPV6(t))) -#define LWIP_DNS_ADDRTYPE_ARG(x) , x -#define LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(x) x -#define LWIP_DNS_SET_ADDRTYPE(x, y) do { x = y; } while(0) -#else -#if LWIP_IPV6 -#define LWIP_DNS_ADDRTYPE_IS_IPV6(t) 1 -#else -#define LWIP_DNS_ADDRTYPE_IS_IPV6(t) 0 -#endif -#define LWIP_DNS_ADDRTYPE_MATCH_IP(t, ip) 1 -#define LWIP_DNS_ADDRTYPE_ARG(x) -#define LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(x) 0 -#define LWIP_DNS_SET_ADDRTYPE(x, y) -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - -#if LWIP_DNS_SUPPORT_MDNS_QUERIES -#define LWIP_DNS_ISMDNS_ARG(x) , x -#else -#define LWIP_DNS_ISMDNS_ARG(x) -#endif - -/** DNS query message structure. - No packing needed: only used locally on the stack. */ -struct dns_query { - /* DNS query record starts with either a domain name or a pointer - to a name already present somewhere in the packet. */ - u16_t type; - u16_t cls; -}; -#define SIZEOF_DNS_QUERY 4 - -/** DNS answer message structure. - No packing needed: only used locally on the stack. */ -struct dns_answer { - /* DNS answer record starts with either a domain name or a pointer - to a name already present somewhere in the packet. */ - u16_t type; - u16_t cls; - u32_t ttl; - u16_t len; -}; -#define SIZEOF_DNS_ANSWER 10 -/* maximum allowed size for the struct due to non-packed */ -#define SIZEOF_DNS_ANSWER_ASSERT 12 - -/* DNS table entry states */ -typedef enum { - DNS_STATE_UNUSED = 0, - DNS_STATE_NEW = 1, - DNS_STATE_ASKING = 2, - DNS_STATE_DONE = 3 -} dns_state_enum_t; - -/** DNS table entry */ -struct dns_table_entry { - u32_t ttl; - ip_addr_t ipaddr; - u16_t txid; - u8_t state; - u8_t server_idx; - u8_t tmr; - u8_t retries; - u8_t seqno; -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) - u8_t pcb_idx; -#endif - char name[DNS_MAX_NAME_LENGTH]; -#if LWIP_IPV4 && LWIP_IPV6 - u8_t reqaddrtype; -#endif /* LWIP_IPV4 && LWIP_IPV6 */ -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - u8_t is_mdns; -#endif -}; - -/** DNS request table entry: used when dns_gehostbyname cannot answer the - * request from the DNS table */ -struct dns_req_entry { - /* pointer to callback on DNS query done */ - dns_found_callback found; - /* argument passed to the callback function */ - void *arg; -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0) - u8_t dns_table_idx; -#endif -#if LWIP_IPV4 && LWIP_IPV6 - u8_t reqaddrtype; -#endif /* LWIP_IPV4 && LWIP_IPV6 */ -}; - -#if DNS_LOCAL_HOSTLIST - -#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC -/** Local host-list. For hostnames in this list, no - * external name resolution is performed */ -static struct local_hostlist_entry *local_hostlist_dynamic; -#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ - -/** Defining this allows the local_hostlist_static to be placed in a different - * linker section (e.g. FLASH) */ -#ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE -#define DNS_LOCAL_HOSTLIST_STORAGE_PRE static -#endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */ -/** Defining this allows the local_hostlist_static to be placed in a different - * linker section (e.g. FLASH) */ -#ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST -#define DNS_LOCAL_HOSTLIST_STORAGE_POST -#endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */ -DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[] - DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT; - -#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ - -static void dns_init_local(void); -static err_t dns_lookup_local(const char *hostname, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype)); -#endif /* DNS_LOCAL_HOSTLIST */ - - -/* forward declarations */ -static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port); - -// KH -#if 0 -static void dns_check_entries(void); -#endif -////// - -static void dns_call_found(u8_t idx, ip_addr_t *addr); - -/*----------------------------------------------------------------------------- - * Globals - *----------------------------------------------------------------------------*/ - -/* DNS variables */ -static struct udp_pcb *dns_pcbs[DNS_MAX_SOURCE_PORTS]; -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) -static u8_t dns_last_pcb_idx; -#endif -static u8_t dns_seqno; -static struct dns_table_entry dns_table[DNS_TABLE_SIZE]; -static struct dns_req_entry dns_requests[DNS_MAX_REQUESTS]; -static ip_addr_t dns_servers[DNS_MAX_SERVERS]; - -// KH -#if 0 -#if LWIP_IPV4 -const ip_addr_t dns_mquery_v4group = DNS_MQUERY_IPV4_GROUP_INIT; -#endif /* LWIP_IPV4 */ -#if LWIP_IPV6 -const ip_addr_t dns_mquery_v6group = DNS_MQUERY_IPV6_GROUP_INIT; -#endif /* LWIP_IPV6 */ - -/** - * Initialize the resolver: set up the UDP pcb and configure the default server - * (if DNS_SERVER_ADDRESS is set). - */ -void -dns_init(void) -{ -#ifdef DNS_SERVER_ADDRESS - /* initialize default DNS server address */ - ip_addr_t dnsserver; - DNS_SERVER_ADDRESS(&dnsserver); - dns_setserver(0, &dnsserver); -#endif /* DNS_SERVER_ADDRESS */ - - LWIP_ASSERT("sanity check SIZEOF_DNS_QUERY", - sizeof(struct dns_query) == SIZEOF_DNS_QUERY); - LWIP_ASSERT("sanity check SIZEOF_DNS_ANSWER", - sizeof(struct dns_answer) <= SIZEOF_DNS_ANSWER_ASSERT); - - LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n")); - - /* if dns client not yet initialized... */ -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) == 0) - if (dns_pcbs[0] == NULL) { - dns_pcbs[0] = udp_new_ip_type(IPADDR_TYPE_ANY); - LWIP_ASSERT("dns_pcbs[0] != NULL", dns_pcbs[0] != NULL); - - /* initialize DNS table not needed (initialized to zero since it is a - * global variable) */ - LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0", - DNS_STATE_UNUSED == 0); - - /* initialize DNS client */ - udp_bind(dns_pcbs[0], IP_ANY_TYPE, 0); - udp_recv(dns_pcbs[0], dns_recv, NULL); - } -#endif - -#if DNS_LOCAL_HOSTLIST - dns_init_local(); -#endif -} - - -/** - * @ingroup dns - * Initialize one of the DNS servers. - * - * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS - * @param dnsserver IP address of the DNS server to set - */ -void -dns_setserver(u8_t numdns, const ip_addr_t *dnsserver) -{ - if (numdns < DNS_MAX_SERVERS) { - if (dnsserver != NULL) { - dns_servers[numdns] = (*dnsserver); - } else { - dns_servers[numdns] = *IP_ADDR_ANY; - } - } -} - -/** - * @ingroup dns - * Obtain one of the currently configured DNS server. - * - * @param numdns the index of the DNS server - * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS - * server has not been configured. - */ -const ip_addr_t * -dns_getserver(u8_t numdns) -{ - if (numdns < DNS_MAX_SERVERS) { - return &dns_servers[numdns]; - } else { - return IP_ADDR_ANY; - } -} - - -/** - * The DNS resolver client timer - handle retries and timeouts and should - * be called every DNS_TMR_INTERVAL milliseconds (every second by default). - */ -void -dns_tmr(void) -{ - LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n")); - dns_check_entries(); -} - -#endif -////////////////////////////////////////// - -#if DNS_LOCAL_HOSTLIST -static void -dns_init_local(void) -{ -#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) - size_t i; - struct local_hostlist_entry *entry; - /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */ - struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT; - size_t namelen; - for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_init); i++) { - struct local_hostlist_entry *init_entry = &local_hostlist_init[i]; - LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL); - namelen = strlen(init_entry->name); - LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN); - entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST); - LWIP_ASSERT("mem-error in dns_init_local", entry != NULL); - if (entry != NULL) { - char *entry_name = (char *)entry + sizeof(struct local_hostlist_entry); - MEMCPY(entry_name, init_entry->name, namelen); - entry_name[namelen] = 0; - entry->name = entry_name; - entry->addr = init_entry->addr; - entry->next = local_hostlist_dynamic; - local_hostlist_dynamic = entry; - } - } -#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */ -} - -/** - * @ingroup dns - * Iterate the local host-list for a hostname. - * - * @param iterator_fn a function that is called for every entry in the local host-list - * @param iterator_arg 3rd argument passed to iterator_fn - * @return the number of entries in the local host-list - */ -size_t -dns_local_iterate(dns_found_callback iterator_fn, void *iterator_arg) -{ - size_t i; -#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC - struct local_hostlist_entry *entry = local_hostlist_dynamic; - i = 0; - while (entry != NULL) { - if (iterator_fn != NULL) { - iterator_fn(entry->name, &entry->addr, iterator_arg); - } - i++; - entry = entry->next; - } -#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ - for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_static); i++) { - if (iterator_fn != NULL) { - iterator_fn(local_hostlist_static[i].name, &local_hostlist_static[i].addr, iterator_arg); - } - } -#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ - return i; -} - -/** - * @ingroup dns - * Scans the local host-list for a hostname. - * - * @param hostname Hostname to look for in the local host-list - * @param addr the first IP address for the hostname in the local host-list or - * IPADDR_NONE if not found. - * @param dns_addrtype - LWIP_DNS_ADDRTYPE_IPV4_IPV6: try to resolve IPv4 (ATTENTION: no fallback here!) - * - LWIP_DNS_ADDRTYPE_IPV6_IPV4: try to resolve IPv6 (ATTENTION: no fallback here!) - * - LWIP_DNS_ADDRTYPE_IPV4: try to resolve IPv4 only - * - LWIP_DNS_ADDRTYPE_IPV6: try to resolve IPv6 only - * @return ERR_OK if found, ERR_ARG if not found - */ -err_t -dns_local_lookup(const char *hostname, ip_addr_t *addr, u8_t dns_addrtype) -{ - LWIP_UNUSED_ARG(dns_addrtype); - return dns_lookup_local(hostname, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)); -} - -/* Internal implementation for dns_local_lookup and dns_lookup */ -static err_t -dns_lookup_local(const char *hostname, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype)) -{ -#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC - struct local_hostlist_entry *entry = local_hostlist_dynamic; - while (entry != NULL) { - if ((lwip_stricmp(entry->name, hostname) == 0) && - LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, entry->addr)) { - if (addr) { - ip_addr_copy(*addr, entry->addr); - } - return ERR_OK; - } - entry = entry->next; - } -#else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ - size_t i; - for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_static); i++) { - if ((lwip_stricmp(local_hostlist_static[i].name, hostname) == 0) && - LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, local_hostlist_static[i].addr)) { - if (addr) { - ip_addr_copy(*addr, local_hostlist_static[i].addr); - } - return ERR_OK; - } - } -#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */ - return ERR_ARG; -} - -#if DNS_LOCAL_HOSTLIST_IS_DYNAMIC -/** - * @ingroup dns - * Remove all entries from the local host-list for a specific hostname - * and/or IP address - * - * @param hostname hostname for which entries shall be removed from the local - * host-list - * @param addr address for which entries shall be removed from the local host-list - * @return the number of removed entries - */ -int -dns_local_removehost(const char *hostname, const ip_addr_t *addr) -{ - int removed = 0; - struct local_hostlist_entry *entry = local_hostlist_dynamic; - struct local_hostlist_entry *last_entry = NULL; - while (entry != NULL) { - if (((hostname == NULL) || !lwip_stricmp(entry->name, hostname)) && - ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) { - struct local_hostlist_entry *free_entry; - if (last_entry != NULL) { - last_entry->next = entry->next; - } else { - local_hostlist_dynamic = entry->next; - } - free_entry = entry; - entry = entry->next; - memp_free(MEMP_LOCALHOSTLIST, free_entry); - removed++; - } else { - last_entry = entry; - entry = entry->next; - } - } - return removed; -} - -/** - * @ingroup dns - * Add a hostname/IP address pair to the local host-list. - * Duplicates are not checked. - * - * @param hostname hostname of the new entry - * @param addr IP address of the new entry - * @return ERR_OK if succeeded or ERR_MEM on memory error - */ -err_t -dns_local_addhost(const char *hostname, const ip_addr_t *addr) -{ - struct local_hostlist_entry *entry; - size_t namelen; - char *entry_name; - LWIP_ASSERT("invalid host name (NULL)", hostname != NULL); - namelen = strlen(hostname); - LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN); - entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST); - if (entry == NULL) { - return ERR_MEM; - } - entry_name = (char *)entry + sizeof(struct local_hostlist_entry); - MEMCPY(entry_name, hostname, namelen); - entry_name[namelen] = 0; - entry->name = entry_name; - ip_addr_copy(entry->addr, *addr); - entry->next = local_hostlist_dynamic; - local_hostlist_dynamic = entry; - return ERR_OK; -} -#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/ -#endif /* DNS_LOCAL_HOSTLIST */ - -/** - * @ingroup dns - * Look up a hostname in the array of known hostnames. - * - * @note This function only looks in the internal array of known - * hostnames, it does not send out a query for the hostname if none - * was found. The function dns_enqueue() can be used to send a query - * for a hostname. - * - * @param name the hostname to look up - * @param addr the hostname's IP address, as u32_t (instead of ip_addr_t to - * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname - * was not found in the cached dns_table. - * @return ERR_OK if found, ERR_ARG if not found - */ -static err_t -dns_lookup(const char *name, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype)) -{ - u8_t i; -#if DNS_LOCAL_HOSTLIST - if (dns_lookup_local(name, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)) == ERR_OK) { - return ERR_OK; - } -#endif /* DNS_LOCAL_HOSTLIST */ -#ifdef DNS_LOOKUP_LOCAL_EXTERN - if (DNS_LOOKUP_LOCAL_EXTERN(name, addr, LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(dns_addrtype)) == ERR_OK) { - return ERR_OK; - } -#endif /* DNS_LOOKUP_LOCAL_EXTERN */ - - /* Walk through name list, return entry if found. If not, return NULL. */ - for (i = 0; i < DNS_TABLE_SIZE; ++i) { - if ((dns_table[i].state == DNS_STATE_DONE) && - (lwip_strnicmp(name, dns_table[i].name, sizeof(dns_table[i].name)) == 0) && - LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, dns_table[i].ipaddr)) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name)); - ip_addr_debug_print_val(DNS_DEBUG, dns_table[i].ipaddr); - LWIP_DEBUGF(DNS_DEBUG, ("\n")); - if (addr) { - ip_addr_copy(*addr, dns_table[i].ipaddr); - } - return ERR_OK; - } - } - - return ERR_ARG; -} - -/** - * Compare the "dotted" name "query" with the encoded name "response" - * to make sure an answer from the DNS server matches the current dns_table - * entry (otherwise, answers might arrive late for hostname not on the list - * any more). - * - * For now, this function compares case-insensitive to cope with all kinds of - * servers. This also means that "dns 0x20 bit encoding" must be checked - * externally, if we want to implement it. - * Currently, the request is sent exactly as passed in by he user request. - * - * @param query hostname (not encoded) from the dns_table - * @param p pbuf containing the encoded hostname in the DNS response - * @param start_offset offset into p where the name starts - * @return 0xFFFF: names differ, other: names equal -> offset behind name - */ -static u16_t -dns_compare_name(const char *query, struct pbuf *p, u16_t start_offset) -{ - int n; - u16_t response_offset = start_offset; - - do { - n = pbuf_try_get_at(p, response_offset); - if ((n < 0) || (response_offset == 0xFFFF)) { - /* error or overflow */ - return 0xFFFF; - } - response_offset++; - /** @see RFC 1035 - 4.1.4. Message compression */ - if ((n & 0xc0) == 0xc0) { - /* Compressed name: cannot be equal since we don't send them */ - return 0xFFFF; - } else { - /* Not compressed name */ - while (n > 0) { - int c = pbuf_try_get_at(p, response_offset); - if (c < 0) { - return 0xFFFF; - } - if (lwip_tolower((*query)) != lwip_tolower((u8_t)c)) { - return 0xFFFF; - } - if (response_offset == 0xFFFF) { - /* would overflow */ - return 0xFFFF; - } - response_offset++; - ++query; - --n; - } - ++query; - } - n = pbuf_try_get_at(p, response_offset); - if (n < 0) { - return 0xFFFF; - } - } while (n != 0); - - if (response_offset == 0xFFFF) { - /* would overflow */ - return 0xFFFF; - } - return (u16_t)(response_offset + 1); -} - -/** - * Walk through a compact encoded DNS name and return the end of the name. - * - * @param p pbuf containing the name - * @param query_idx start index into p pointing to encoded DNS name in the DNS server response - * @return index to end of the name - */ -static u16_t -dns_skip_name(struct pbuf *p, u16_t query_idx) -{ - int n; - u16_t offset = query_idx; - - do { - n = pbuf_try_get_at(p, offset++); - if ((n < 0) || (offset == 0)) { - return 0xFFFF; - } - /** @see RFC 1035 - 4.1.4. Message compression */ - if ((n & 0xc0) == 0xc0) { - /* Compressed name: since we only want to skip it (not check it), stop here */ - break; - } else { - /* Not compressed name */ - if (offset + n >= p->tot_len) { - return 0xFFFF; - } - offset = (u16_t)(offset + n); - } - n = pbuf_try_get_at(p, offset); - if (n < 0) { - return 0xFFFF; - } - } while (n != 0); - - if (offset == 0xFFFF) { - return 0xFFFF; - } - return (u16_t)(offset + 1); -} - -/** - * Send a DNS query packet. - * - * @param idx the DNS table entry index for which to send a request - * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise - */ -static err_t -dns_send(u8_t idx) -{ - err_t err; - struct dns_hdr hdr; - struct dns_query qry; - struct pbuf *p; - u16_t query_idx, copy_len; - const char *hostname, *hostname_part; - u8_t n; - u8_t pcb_idx; - struct dns_table_entry *entry = &dns_table[idx]; - - LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n", - (u16_t)(entry->server_idx), entry->name)); - LWIP_ASSERT("dns server out of array", entry->server_idx < DNS_MAX_SERVERS); - if (ip_addr_isany_val(dns_servers[entry->server_idx]) -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - && !entry->is_mdns -#endif - ) { - /* DNS server not valid anymore, e.g. PPP netif has been shut down */ - /* call specified callback function if provided */ - dns_call_found(idx, NULL); - /* flush this entry */ - entry->state = DNS_STATE_UNUSED; - return ERR_OK; - } - - /* if here, we have either a new query or a retry on a previous query to process */ - p = pbuf_alloc(PBUF_TRANSPORT, (u16_t)(SIZEOF_DNS_HDR + strlen(entry->name) + 2 + - SIZEOF_DNS_QUERY), PBUF_RAM); - if (p != NULL) { - const ip_addr_t *dst; - u16_t dst_port; - /* fill dns header */ - memset(&hdr, 0, SIZEOF_DNS_HDR); - hdr.id = lwip_htons(entry->txid); - hdr.flags1 = DNS_FLAG1_RD; - hdr.numquestions = PP_HTONS(1); - pbuf_take(p, &hdr, SIZEOF_DNS_HDR); - hostname = entry->name; - --hostname; - - /* convert hostname into suitable query format. */ - query_idx = SIZEOF_DNS_HDR; - do { - ++hostname; - hostname_part = hostname; - for (n = 0; *hostname != '.' && *hostname != 0; ++hostname) { - ++n; - } - copy_len = (u16_t)(hostname - hostname_part); - if (query_idx + n + 1 > 0xFFFF) { - /* u16_t overflow */ - goto overflow_return; - } - pbuf_put_at(p, query_idx, n); - pbuf_take_at(p, hostname_part, copy_len, (u16_t)(query_idx + 1)); - query_idx = (u16_t)(query_idx + n + 1); - } while (*hostname != 0); - pbuf_put_at(p, query_idx, 0); - query_idx++; - - /* fill dns query */ - if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype)) { - qry.type = PP_HTONS(DNS_RRTYPE_AAAA); - } else { - qry.type = PP_HTONS(DNS_RRTYPE_A); - } - qry.cls = PP_HTONS(DNS_RRCLASS_IN); - pbuf_take_at(p, &qry, SIZEOF_DNS_QUERY, query_idx); - -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) - pcb_idx = entry->pcb_idx; -#else - pcb_idx = 0; -#endif - /* send dns packet */ - LWIP_DEBUGF(DNS_DEBUG, ("sending DNS request ID %d for name \"%s\" to server %d\r\n", - entry->txid, entry->name, entry->server_idx)); -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - if (entry->is_mdns) { - dst_port = DNS_MQUERY_PORT; -#if LWIP_IPV6 - if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype)) { - dst = &dns_mquery_v6group; - } -#endif -#if LWIP_IPV4 && LWIP_IPV6 - else -#endif -#if LWIP_IPV4 - { - dst = &dns_mquery_v4group; - } -#endif - } else -#endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */ - { - dst_port = DNS_SERVER_PORT; - dst = &dns_servers[entry->server_idx]; - } - err = udp_sendto(dns_pcbs[pcb_idx], p, dst, dst_port); - - /* free pbuf */ - pbuf_free(p); - } else { - err = ERR_MEM; - } - - return err; -overflow_return: - pbuf_free(p); - return ERR_VAL; -} - -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) -static struct udp_pcb * -dns_alloc_random_port(void) -{ - err_t err; - struct udp_pcb *pcb; - - pcb = udp_new_ip_type(IPADDR_TYPE_ANY); - if (pcb == NULL) { - /* out of memory, have to reuse an existing pcb */ - return NULL; - } - do { - u16_t port = (u16_t)DNS_RAND_TXID(); - if (DNS_PORT_ALLOWED(port)) { - err = udp_bind(pcb, IP_ANY_TYPE, port); - } else { - /* this port is not allowed, try again */ - err = ERR_USE; - } - } while (err == ERR_USE); - if (err != ERR_OK) { - udp_remove(pcb); - return NULL; - } - udp_recv(pcb, dns_recv, NULL); - return pcb; -} - -/** - * dns_alloc_pcb() - allocates a new pcb (or reuses an existing one) to be used - * for sending a request - * - * @return an index into dns_pcbs - */ -static u8_t -dns_alloc_pcb(void) -{ - u8_t i; - u8_t idx; - - for (i = 0; i < DNS_MAX_SOURCE_PORTS; i++) { - if (dns_pcbs[i] == NULL) { - break; - } - } - if (i < DNS_MAX_SOURCE_PORTS) { - dns_pcbs[i] = dns_alloc_random_port(); - if (dns_pcbs[i] != NULL) { - /* succeeded */ - dns_last_pcb_idx = i; - return i; - } - } - /* if we come here, creating a new UDP pcb failed, so we have to use - an already existing one (so overflow is no issue) */ - for (i = 0, idx = (u8_t)(dns_last_pcb_idx + 1); i < DNS_MAX_SOURCE_PORTS; i++, idx++) { - if (idx >= DNS_MAX_SOURCE_PORTS) { - idx = 0; - } - if (dns_pcbs[idx] != NULL) { - dns_last_pcb_idx = idx; - return idx; - } - } - return DNS_MAX_SOURCE_PORTS; -} -#endif /* ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) */ - -/** - * dns_call_found() - call the found callback and check if there are duplicate - * entries for the given hostname. If there are any, their found callback will - * be called and they will be removed. - * - * @param idx dns table index of the entry that is resolved or removed - * @param addr IP address for the hostname (or NULL on error or memory shortage) - */ -static void -dns_call_found(u8_t idx, ip_addr_t *addr) -{ -#if ((LWIP_DNS_SECURE & (LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING | LWIP_DNS_SECURE_RAND_SRC_PORT)) != 0) - u8_t i; -#endif - -#if LWIP_IPV4 && LWIP_IPV6 - if (addr != NULL) { - /* check that address type matches the request and adapt the table entry */ - if (IP_IS_V6_VAL(*addr)) { - LWIP_ASSERT("invalid response", LWIP_DNS_ADDRTYPE_IS_IPV6(dns_table[idx].reqaddrtype)); - dns_table[idx].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV6; - } else { - LWIP_ASSERT("invalid response", !LWIP_DNS_ADDRTYPE_IS_IPV6(dns_table[idx].reqaddrtype)); - dns_table[idx].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV4; - } - } -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0) - for (i = 0; i < DNS_MAX_REQUESTS; i++) { - if (dns_requests[i].found && (dns_requests[i].dns_table_idx == idx)) { - (*dns_requests[i].found)(dns_table[idx].name, addr, dns_requests[i].arg); - /* flush this entry */ - dns_requests[i].found = NULL; - } - } -#else - if (dns_requests[idx].found) { - (*dns_requests[idx].found)(dns_table[idx].name, addr, dns_requests[idx].arg); - } - dns_requests[idx].found = NULL; -#endif -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) - /* close the pcb used unless other request are using it */ - for (i = 0; i < DNS_MAX_REQUESTS; i++) { - if (i == idx) { - continue; /* only check other requests */ - } - if (dns_table[i].state == DNS_STATE_ASKING) { - if (dns_table[i].pcb_idx == dns_table[idx].pcb_idx) { - /* another request is still using the same pcb */ - dns_table[idx].pcb_idx = DNS_MAX_SOURCE_PORTS; - break; - } - } - } - if (dns_table[idx].pcb_idx < DNS_MAX_SOURCE_PORTS) { - /* if we come here, the pcb is not used any more and can be removed */ - udp_remove(dns_pcbs[dns_table[idx].pcb_idx]); - dns_pcbs[dns_table[idx].pcb_idx] = NULL; - dns_table[idx].pcb_idx = DNS_MAX_SOURCE_PORTS; - } -#endif -} - -/* Create a query transmission ID that is unique for all outstanding queries */ -static u16_t -dns_create_txid(void) -{ - u16_t txid; - u8_t i; - -again: - txid = (u16_t)DNS_RAND_TXID(); - - /* check whether the ID is unique */ - for (i = 0; i < DNS_TABLE_SIZE; i++) { - if ((dns_table[i].state == DNS_STATE_ASKING) && - (dns_table[i].txid == txid)) { - /* ID already used by another pending query */ - goto again; - } - } - - return txid; -} - -/** - * Check whether there are other backup DNS servers available to try - */ -static u8_t -dns_backupserver_available(struct dns_table_entry *pentry) -{ - u8_t ret = 0; - - if (pentry) { - if ((pentry->server_idx + 1 < DNS_MAX_SERVERS) && !ip_addr_isany_val(dns_servers[pentry->server_idx + 1])) { - ret = 1; - } - } - - return ret; -} - -/** - * dns_check_entry() - see if entry has not yet been queried and, if so, sends out a query. - * Check an entry in the dns_table: - * - send out query for new entries - * - retry old pending entries on timeout (also with different servers) - * - remove completed entries from the table if their TTL has expired - * - * @param i index of the dns_table entry to check - */ -static void -dns_check_entry(u8_t i) -{ - err_t err; - struct dns_table_entry *entry = &dns_table[i]; - - LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE); - - switch (entry->state) { - case DNS_STATE_NEW: - /* initialize new entry */ - entry->txid = dns_create_txid(); - entry->state = DNS_STATE_ASKING; - entry->server_idx = 0; - entry->tmr = 1; - entry->retries = 0; - - /* send DNS packet for this entry */ - err = dns_send(i); - if (err != ERR_OK) { - LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING, - ("dns_send returned error: %s\n", lwip_strerr(err))); - } - break; - case DNS_STATE_ASKING: - if (--entry->tmr == 0) { - if (++entry->retries == DNS_MAX_RETRIES) { - if (dns_backupserver_available(entry) -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - && !entry->is_mdns -#endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */ - ) { - /* change of server */ - entry->server_idx++; - entry->tmr = 1; - entry->retries = 0; - } else { - LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", entry->name)); - /* call specified callback function if provided */ - dns_call_found(i, NULL); - /* flush this entry */ - entry->state = DNS_STATE_UNUSED; - break; - } - } else { - /* wait longer for the next retry */ - entry->tmr = entry->retries; - } - - /* send DNS packet for this entry */ - err = dns_send(i); - if (err != ERR_OK) { - LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING, - ("dns_send returned error: %s\n", lwip_strerr(err))); - } - } - break; - case DNS_STATE_DONE: - /* if the time to live is nul */ - if ((entry->ttl == 0) || (--entry->ttl == 0)) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", entry->name)); - /* flush this entry, there cannot be any related pending entries in this state */ - entry->state = DNS_STATE_UNUSED; - } - break; - case DNS_STATE_UNUSED: - /* nothing to do */ - break; - default: - LWIP_ASSERT("unknown dns_table entry state:", 0); - break; - } -} - -// KH -#if 0 -/** - * Call dns_check_entry for each entry in dns_table - check all entries. - */ -static void -dns_check_entries(void) -{ - u8_t i; - - for (i = 0; i < DNS_TABLE_SIZE; ++i) { - dns_check_entry(i); - } -} -#endif -////////// - -/** - * Save TTL and call dns_call_found for correct response. - */ -static void -dns_correct_response(u8_t idx, u32_t ttl) -{ - struct dns_table_entry *entry = &dns_table[idx]; - - entry->state = DNS_STATE_DONE; - - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", entry->name)); - ip_addr_debug_print_val(DNS_DEBUG, entry->ipaddr); - LWIP_DEBUGF(DNS_DEBUG, ("\n")); - - /* read the answer resource record's TTL, and maximize it if needed */ - entry->ttl = ttl; - if (entry->ttl > DNS_MAX_TTL) { - entry->ttl = DNS_MAX_TTL; - } - dns_call_found(idx, &entry->ipaddr); - - if (entry->ttl == 0) { - /* RFC 883, page 29: "Zero values are - interpreted to mean that the RR can only be used for the - transaction in progress, and should not be cached." - -> flush this entry now */ - /* entry reused during callback? */ - if (entry->state == DNS_STATE_DONE) { - entry->state = DNS_STATE_UNUSED; - } - } -} - -/** - * Receive input function for DNS response packets arriving for the dns UDP pcb. - */ -static void -dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port) -{ - u8_t i; - u16_t txid; - u16_t res_idx; - struct dns_hdr hdr; - struct dns_answer ans; - struct dns_query qry; - u16_t nquestions, nanswers; - - LWIP_UNUSED_ARG(arg); - LWIP_UNUSED_ARG(pcb); - LWIP_UNUSED_ARG(port); - - /* is the dns message big enough ? */ - if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY)) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n")); - /* free pbuf and return */ - goto ignore_packet; - } - - /* copy dns payload inside static buffer for processing */ - if (pbuf_copy_partial(p, &hdr, SIZEOF_DNS_HDR, 0) == SIZEOF_DNS_HDR) { - /* Match the ID in the DNS header with the name table. */ - txid = lwip_htons(hdr.id); - for (i = 0; i < DNS_TABLE_SIZE; i++) { - struct dns_table_entry *entry = &dns_table[i]; - if ((entry->state == DNS_STATE_ASKING) && - (entry->txid == txid)) { - - /* We only care about the question(s) and the answers. The authrr - and the extrarr are simply discarded. */ - nquestions = lwip_htons(hdr.numquestions); - nanswers = lwip_htons(hdr.numanswers); - - /* Check for correct response. */ - if ((hdr.flags1 & DNS_FLAG1_RESPONSE) == 0) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": not a response\n", entry->name)); - goto ignore_packet; /* ignore this packet */ - } - if (nquestions != 1) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name)); - goto ignore_packet; /* ignore this packet */ - } - -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - if (!entry->is_mdns) -#endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */ - { - /* Check whether response comes from the same network address to which the - question was sent. (RFC 5452) */ - if (!ip_addr_cmp(addr, &dns_servers[entry->server_idx])) { - goto ignore_packet; /* ignore this packet */ - } - } - - /* Check if the name in the "question" part match with the name in the entry and - skip it if equal. */ - res_idx = dns_compare_name(entry->name, p, SIZEOF_DNS_HDR); - if (res_idx == 0xFFFF) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name)); - goto ignore_packet; /* ignore this packet */ - } - - /* check if "question" part matches the request */ - if (pbuf_copy_partial(p, &qry, SIZEOF_DNS_QUERY, res_idx) != SIZEOF_DNS_QUERY) { - goto ignore_packet; /* ignore this packet */ - } - if ((qry.cls != PP_HTONS(DNS_RRCLASS_IN)) || - (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype) && (qry.type != PP_HTONS(DNS_RRTYPE_AAAA))) || - (!LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype) && (qry.type != PP_HTONS(DNS_RRTYPE_A)))) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name)); - goto ignore_packet; /* ignore this packet */ - } - /* skip the rest of the "question" part */ - if (res_idx + SIZEOF_DNS_QUERY > 0xFFFF) { - goto ignore_packet; - } - res_idx = (u16_t)(res_idx + SIZEOF_DNS_QUERY); - - /* Check for error. If so, call callback to inform. */ - if (hdr.flags2 & DNS_FLAG2_ERR_MASK) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", entry->name)); - - /* if there is another backup DNS server to try - * then don't stop the DNS request - */ - if (dns_backupserver_available(entry)) { - /* avoid retrying the same server */ - entry->retries = DNS_MAX_RETRIES-1; - entry->tmr = 1; - - /* contact next available server for this entry */ - dns_check_entry(i); - - goto ignore_packet; - } - } else { - while ((nanswers > 0) && (res_idx < p->tot_len)) { - /* skip answer resource record's host name */ - res_idx = dns_skip_name(p, res_idx); - if (res_idx == 0xFFFF) { - goto ignore_packet; /* ignore this packet */ - } - - /* Check for IP address type and Internet class. Others are discarded. */ - if (pbuf_copy_partial(p, &ans, SIZEOF_DNS_ANSWER, res_idx) != SIZEOF_DNS_ANSWER) { - goto ignore_packet; /* ignore this packet */ - } - if (res_idx + SIZEOF_DNS_ANSWER > 0xFFFF) { - goto ignore_packet; - } - res_idx = (u16_t)(res_idx + SIZEOF_DNS_ANSWER); - - if (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) { -#if LWIP_IPV4 - if ((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.len == PP_HTONS(sizeof(ip4_addr_t)))) { -#if LWIP_IPV4 && LWIP_IPV6 - if (!LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype)) -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - { - ip4_addr_t ip4addr; - /* read the IP address after answer resource record's header */ - if (pbuf_copy_partial(p, &ip4addr, sizeof(ip4_addr_t), res_idx) != sizeof(ip4_addr_t)) { - goto ignore_packet; /* ignore this packet */ - } - ip_addr_copy_from_ip4(dns_table[i].ipaddr, ip4addr); - pbuf_free(p); - /* handle correct response */ - dns_correct_response(i, lwip_ntohl(ans.ttl)); - return; - } - } -#endif /* LWIP_IPV4 */ -#if LWIP_IPV6 - if ((ans.type == PP_HTONS(DNS_RRTYPE_AAAA)) && (ans.len == PP_HTONS(sizeof(ip6_addr_p_t)))) { -#if LWIP_IPV4 && LWIP_IPV6 - if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype)) -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - { - ip6_addr_p_t ip6addr; - /* read the IP address after answer resource record's header */ - if (pbuf_copy_partial(p, &ip6addr, sizeof(ip6_addr_p_t), res_idx) != sizeof(ip6_addr_p_t)) { - goto ignore_packet; /* ignore this packet */ - } - /* @todo: scope ip6addr? Might be required for link-local addresses at least? */ - ip_addr_copy_from_ip6_packed(dns_table[i].ipaddr, ip6addr); - pbuf_free(p); - /* handle correct response */ - dns_correct_response(i, lwip_ntohl(ans.ttl)); - return; - } - } -#endif /* LWIP_IPV6 */ - } - /* skip this answer */ - if ((int)(res_idx + lwip_htons(ans.len)) > 0xFFFF) { - goto ignore_packet; /* ignore this packet */ - } - res_idx = (u16_t)(res_idx + lwip_htons(ans.len)); - --nanswers; - } -#if LWIP_IPV4 && LWIP_IPV6 - if ((entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) || - (entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV6_IPV4)) { - if (entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) { - /* IPv4 failed, try IPv6 */ - dns_table[i].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV6; - } else { - /* IPv6 failed, try IPv4 */ - dns_table[i].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV4; - } - pbuf_free(p); - dns_table[i].state = DNS_STATE_NEW; - dns_check_entry(i); - return; - } -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", entry->name)); - } - /* call callback to indicate error, clean up memory and return */ - pbuf_free(p); - dns_call_found(i, NULL); - dns_table[i].state = DNS_STATE_UNUSED; - return; - } - } - } - -ignore_packet: - /* deallocate memory and return */ - pbuf_free(p); - return; -} - -/** - * Queues a new hostname to resolve and sends out a DNS query for that hostname - * - * @param name the hostname that is to be queried - * @param hostnamelen length of the hostname - * @param found a callback function to be called on success, failure or timeout - * @param callback_arg argument to pass to the callback function - * @return err_t return code. - */ -static err_t -dns_enqueue(const char *name, size_t hostnamelen, dns_found_callback found, - void *callback_arg LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype) LWIP_DNS_ISMDNS_ARG(u8_t is_mdns)) -{ - u8_t i; - u8_t lseq, lseqi; - struct dns_table_entry *entry = NULL; - size_t namelen; - struct dns_req_entry *req; - -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0) - u8_t r; - /* check for duplicate entries */ - for (i = 0; i < DNS_TABLE_SIZE; i++) { - if ((dns_table[i].state == DNS_STATE_ASKING) && - (lwip_strnicmp(name, dns_table[i].name, sizeof(dns_table[i].name)) == 0)) { -#if LWIP_IPV4 && LWIP_IPV6 - if (dns_table[i].reqaddrtype != dns_addrtype) { - /* requested address types don't match - this can lead to 2 concurrent requests, but mixing the address types - for the same host should not be that common */ - continue; - } -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - /* this is a duplicate entry, find a free request entry */ - for (r = 0; r < DNS_MAX_REQUESTS; r++) { - if (dns_requests[r].found == 0) { - dns_requests[r].found = found; - dns_requests[r].arg = callback_arg; - dns_requests[r].dns_table_idx = i; - LWIP_DNS_SET_ADDRTYPE(dns_requests[r].reqaddrtype, dns_addrtype); - LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": duplicate request\n", name)); - return ERR_INPROGRESS; - } - } - } - } - /* no duplicate entries found */ -#endif - - /* search an unused entry, or the oldest one */ - lseq = 0; - lseqi = DNS_TABLE_SIZE; - for (i = 0; i < DNS_TABLE_SIZE; ++i) { - entry = &dns_table[i]; - /* is it an unused entry ? */ - if (entry->state == DNS_STATE_UNUSED) { - break; - } - /* check if this is the oldest completed entry */ - if (entry->state == DNS_STATE_DONE) { - u8_t age = (u8_t)(dns_seqno - entry->seqno); - if (age > lseq) { - lseq = age; - lseqi = i; - } - } - } - - /* if we don't have found an unused entry, use the oldest completed one */ - if (i == DNS_TABLE_SIZE) { - if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) { - /* no entry can be used now, table is full */ - LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name)); - return ERR_MEM; - } else { - /* use the oldest completed one */ - i = lseqi; - entry = &dns_table[i]; - } - } - -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0) - /* find a free request entry */ - req = NULL; - for (r = 0; r < DNS_MAX_REQUESTS; r++) { - if (dns_requests[r].found == NULL) { - req = &dns_requests[r]; - break; - } - } - if (req == NULL) { - /* no request entry can be used now, table is full */ - LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS request entries table is full\n", name)); - return ERR_MEM; - } - req->dns_table_idx = i; -#else - /* in this configuration, the entry index is the same as the request index */ - req = &dns_requests[i]; -#endif - - /* use this entry */ - LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i))); - - /* fill the entry */ - entry->state = DNS_STATE_NEW; - entry->seqno = dns_seqno; - LWIP_DNS_SET_ADDRTYPE(entry->reqaddrtype, dns_addrtype); - LWIP_DNS_SET_ADDRTYPE(req->reqaddrtype, dns_addrtype); - req->found = found; - req->arg = callback_arg; - namelen = LWIP_MIN(hostnamelen, DNS_MAX_NAME_LENGTH - 1); - MEMCPY(entry->name, name, namelen); - entry->name[namelen] = 0; - -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) - entry->pcb_idx = dns_alloc_pcb(); - if (entry->pcb_idx >= DNS_MAX_SOURCE_PORTS) { - /* failed to get a UDP pcb */ - LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": failed to allocate a pcb\n", name)); - entry->state = DNS_STATE_UNUSED; - req->found = NULL; - return ERR_MEM; - } - LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS pcb %"U16_F"\n", name, (u16_t)(entry->pcb_idx))); -#endif - -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - entry->is_mdns = is_mdns; -#endif - - dns_seqno++; - - /* force to send query without waiting timer */ - dns_check_entry(i); - - /* dns query is enqueued */ - return ERR_INPROGRESS; -} - -/** - * @ingroup dns - * Resolve a hostname (string) into an IP address. - * NON-BLOCKING callback version for use with raw API!!! - * - * Returns immediately with one of err_t return codes: - * - ERR_OK if hostname is a valid IP address string or the host - * name is already in the local names table. - * - ERR_INPROGRESS enqueue a request to be sent to the DNS server - * for resolution if no errors are present. - * - ERR_ARG: dns client not initialized or invalid hostname - * - * @param hostname the hostname that is to be queried - * @param addr pointer to a ip_addr_t where to store the address if it is already - * cached in the dns_table (only valid if ERR_OK is returned!) - * @param found a callback function to be called on success, failure or timeout (only if - * ERR_INPROGRESS is returned!) - * @param callback_arg argument to pass to the callback function - * @return a err_t return code. - */ -err_t -dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found, - void *callback_arg) -{ - return dns_gethostbyname_addrtype(hostname, addr, found, callback_arg, LWIP_DNS_ADDRTYPE_DEFAULT); -} - -/** - * @ingroup dns - * Like dns_gethostbyname, but returned address type can be controlled: - * @param hostname the hostname that is to be queried - * @param addr pointer to a ip_addr_t where to store the address if it is already - * cached in the dns_table (only valid if ERR_OK is returned!) - * @param found a callback function to be called on success, failure or timeout (only if - * ERR_INPROGRESS is returned!) - * @param callback_arg argument to pass to the callback function - * @param dns_addrtype - LWIP_DNS_ADDRTYPE_IPV4_IPV6: try to resolve IPv4 first, try IPv6 if IPv4 fails only - * - LWIP_DNS_ADDRTYPE_IPV6_IPV4: try to resolve IPv6 first, try IPv4 if IPv6 fails only - * - LWIP_DNS_ADDRTYPE_IPV4: try to resolve IPv4 only - * - LWIP_DNS_ADDRTYPE_IPV6: try to resolve IPv6 only - */ -err_t -dns_gethostbyname_addrtype(const char *hostname, ip_addr_t *addr, dns_found_callback found, - void *callback_arg, u8_t dns_addrtype) -{ - size_t hostnamelen; -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - u8_t is_mdns; -#endif - /* not initialized or no valid server yet, or invalid addr pointer - * or invalid hostname or invalid hostname length */ - if ((addr == NULL) || - (!hostname) || (!hostname[0])) { - return ERR_ARG; - } -#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) == 0) - if (dns_pcbs[0] == NULL) { - return ERR_ARG; - } -#endif - hostnamelen = strlen(hostname); - if (hostnamelen >= DNS_MAX_NAME_LENGTH) { - LWIP_DEBUGF(DNS_DEBUG, ("dns_gethostbyname: name too long to resolve")); - return ERR_ARG; - } - - -#if LWIP_HAVE_LOOPIF - if (strcmp(hostname, "localhost") == 0) { - ip_addr_set_loopback(LWIP_DNS_ADDRTYPE_IS_IPV6(dns_addrtype), addr); - return ERR_OK; - } -#endif /* LWIP_HAVE_LOOPIF */ - - /* host name already in octet notation? set ip addr and return ERR_OK */ - if (ipaddr_aton(hostname, addr)) { -#if LWIP_IPV4 && LWIP_IPV6 - if ((IP_IS_V6(addr) && (dns_addrtype != LWIP_DNS_ADDRTYPE_IPV4)) || - (IP_IS_V4(addr) && (dns_addrtype != LWIP_DNS_ADDRTYPE_IPV6))) -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - { - return ERR_OK; - } - } - /* already have this address cached? */ - if (dns_lookup(hostname, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)) == ERR_OK) { - return ERR_OK; - } -#if LWIP_IPV4 && LWIP_IPV6 - if ((dns_addrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) || (dns_addrtype == LWIP_DNS_ADDRTYPE_IPV6_IPV4)) { - /* fallback to 2nd IP type and try again to lookup */ - u8_t fallback; - if (dns_addrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) { - fallback = LWIP_DNS_ADDRTYPE_IPV6; - } else { - fallback = LWIP_DNS_ADDRTYPE_IPV4; - } - if (dns_lookup(hostname, addr LWIP_DNS_ADDRTYPE_ARG(fallback)) == ERR_OK) { - return ERR_OK; - } - } -#else /* LWIP_IPV4 && LWIP_IPV6 */ - LWIP_UNUSED_ARG(dns_addrtype); -#endif /* LWIP_IPV4 && LWIP_IPV6 */ - -#if LWIP_DNS_SUPPORT_MDNS_QUERIES - if (strstr(hostname, ".local") == &hostname[hostnamelen] - 6) { - is_mdns = 1; - } else { - is_mdns = 0; - } - - if (!is_mdns) -#endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */ - { - /* prevent calling found callback if no server is set, return error instead */ - if (ip_addr_isany_val(dns_servers[0])) { - return ERR_VAL; - } - } - - /* queue query with specified callback */ - return dns_enqueue(hostname, hostnamelen, found, callback_arg LWIP_DNS_ADDRTYPE_ARG(dns_addrtype) - LWIP_DNS_ISMDNS_ARG(is_mdns)); -} - -#endif /* LWIP_DNS */