//=============================================================================////      dns.c////      DNS client code////=============================================================================//####ECOSGPLCOPYRIGHTBEGIN####// -------------------------------------------// This file is part of eCos, the Embedded Configurable Operating System.// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.// Copyright (C) 2003 Gary Thomas//// eCos is free software; you can redistribute it and/or modify it under// the terms of the GNU General Public License as published by the Free// Software Foundation; either version 2 or (at your option) any later version.//// eCos is distributed in the hope that it will be useful, but WITHOUT ANY// WARRANTY; without even the implied warranty of MERCHANTABILITY or// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License// for more details.//// You should have received a copy of the GNU General Public License along// with eCos; if not, write to the Free Software Foundation, Inc.,// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.//// As a special exception, if other files instantiate templates or use macros// or inline functions from this file, or you compile this file and link it// with other works to produce a work based on this file, this file does not// by itself cause the resulting work to be covered by the GNU General Public// License. However the source code for this file must still be made available// in accordance with section (3) of the GNU General Public License.//// This exception does not invalidate any other reasons why a work based on// this file might be covered by the GNU General Public License.//// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.// at http://sources.redhat.com/ecos/ecos-license/// -------------------------------------------//####ECOSGPLCOPYRIGHTEND####//=============================================================================//#####DESCRIPTIONBEGIN####//// Author(s):   jskov// Contributors:jskov// Date:        2001-09-26// Description: Provides DNS lookup as per RFC 1034/1035.// // Note:        This is a stripped down clone of dns.c from the CYGPKG_NS_DNS//              package which does not use malloc/free and has been tweaked to//              use UDP via RedBoot's network stack. Also adds commands//              to set the DNS server IP at runtime.////####DESCRIPTIONEND####////=============================================================================#include <cyg/hal/drv_api.h>#include <cyg/infra/cyg_type.h>#include <cyg/infra/cyg_trac.h>         /* Tracing support */#include <net/net.h>#include <redboot.h>/* #include <cyg/ns/dns/dns.h> - it's been moved to redboot.h */#include <cyg/ns/dns/dns_priv.h>#ifdef CYGSEM_REDBOOT_FLASH_CONFIG#include <flash_config.h>RedBoot_config_option("DNS server IP address",                      dns_ip,                      ALWAYS_ENABLED, true,                      CONFIG_IP,                      0    );#endif/* So we remember which ports have been used */static int get_port = 7700;#define DOMAIN_PORT           53/* Some magic to make dns_impl.inl compile under RedBoot */#define sprintf diag_sprintf/* DNS server address possibly returned from bootp */struct in_addr __bootp_dns_addr;cyg_bool __bootp_dns_set = false;struct sockaddr_in server;/* static buffers so we can make do without malloc */static struct hostent _hent;static char* _h_addr_list[2];static struct in_addr _h_addr_list0;static int _hent_alloc = 0;#define _STRING_COUNT  2#define _STRING_LENGTH 64static char _strings[_STRING_COUNT][_STRING_LENGTH];static int _strings_alloc = 0;/* as in dns.c proper */static short id = 0;              /* ID of the last query */static int s = -1;                /* Socket to the DNS server */static cyg_drv_mutex_t dns_mutex; /* Mutex to stop multiple queries as once */static char * domainname=NULL;    /* Domain name used for queries *//* Allocate space for string of length (len). Return NULL on   failure. */static char*alloc_string(int len){    int i;    if (len > _STRING_LENGTH)        return NULL;    for (i = 0; i < _STRING_COUNT; i++) {        if (_strings_alloc & (1 << i)) continue;        _strings_alloc |= (1<<i);        return _strings[i];    }    return NULL;}static voidfree_string(char* s){    int i;    for (i = 0; i < _STRING_COUNT; i++) {        if (_strings[i] == s) {            _strings_alloc &= ~(1<<i);            break;        }    }}/* Deallocate the memory taken to hold a hent structure */static voidfree_hent(struct hostent * hent){    if (hent->h_name) {        free_string(hent->h_name);    }    _hent_alloc = 0;}/* Allocate hent structure with room for one in_addr. Returns NULL on   failure. */static struct hostent*alloc_hent(void){    struct hostent *hent;    if (_hent_alloc) return NULL;    hent = &_hent;    memset(hent, 0, sizeof(struct hostent));    hent->h_addr_list = _h_addr_list;    hent->h_addr_list[0] = (char*)&_h_addr_list0;    hent->h_addr_list[1] = NULL;    _hent_alloc = 1;    return hent;}static __inline__ voidfree_stored_hent(void){    free_hent( &_hent );}static __inline__ voidstore_hent(struct hostent *hent){    hent=hent; // avoid warning}/* Send the query to the server and read the response back. Return -1   if it fails, otherwise put the response back in msg and return the   length of the response. */static int send_recv(char * msg, int len, int msglen){    struct dns_header *dns_hdr;    int finished = false;    int read = 0;    dns_hdr = (struct dns_header *) msg;    do {         int len_togo = len;        struct timeval timeout;        struct sockaddr_in local_addr, from_addr;        memset((char *)&local_addr, 0, sizeof(local_addr));        local_addr.sin_family = AF_INET;        local_addr.sin_addr.s_addr = htonl(INADDR_ANY);        local_addr.sin_port = htons(get_port++);        if (__udp_sendto(msg, len_togo, &server, &local_addr) < 0)            return -1;        memset((char *)&from_addr, 0, sizeof(from_addr));        timeout.tv_sec = CYGNUM_REDBOOT_NETWORKING_DNS_TIMEOUT;        timeout.tv_usec = 0;        read = __udp_recvfrom(msg, len, &from_addr, &local_addr, &timeout);        if (read < 0)            return -1;        /* Reply to an old query. Ignore it */        if (ntohs(dns_hdr->id) != (id-1)) {            continue;        }        finished = true;    } while (!finished);    return read;}    voidset_dns(char* new_ip){    in_addr_t dns_ip;    memset(&server.sin_addr, 0, sizeof(server.sin_addr));    if (!inet_aton(new_ip, &dns_ip)) {        diag_printf("Bad DNS server address: %s\n", new_ip);    } else {        memcpy(&server.sin_addr, &dns_ip, sizeof(dns_ip));        /* server config is valid */        s = 0;    }}voidshow_dns(void){    diag_printf(", DNS server IP: %s", inet_ntoa((in_addr_t *)&server.sin_addr));    if (0 == server.sin_addr.s_addr) {        s = -1;    }}/* Initialise the resolver. Open a socket and bind it to the address   of the server.  return -1 if something goes wrong, otherwise 0 */int  redboot_dns_res_init(void){    memset((char *)&server, 0, sizeof(server));    server.sin_len = sizeof(server);    server.sin_family = AF_INET;    server.sin_port = htons(DOMAIN_PORT);    cyg_drv_mutex_init(&dns_mutex);    /* If we got a DNS server address from the DHCP/BOOTP, then use that address */    if ( __bootp_dns_set ) {	memcpy(&server.sin_addr, &__bootp_dns_addr, sizeof(__bootp_dns_addr) );	s = 0;    }    else {#ifdef CYGSEM_REDBOOT_FLASH_CONFIG    {        ip_addr_t dns_ip;        flash_get_config("dns_ip", &dns_ip, CONFIG_IP);        if (dns_ip[0] == 0 && dns_ip[1] == 0 && dns_ip[2] == 0 && dns_ip[3] == 0)            return -1;        memcpy(&server.sin_addr, &dns_ip, sizeof(dns_ip));        /* server config is valid */        s = 0;    }#else      // Use static configuration	set_dns(__Xstr(CYGPKG_REDBOOT_NETWORKING_DNS_IP));#endif    }    return 0;}/* Include the DNS client implementation code */#include <cyg/ns/dns/dns_impl.inl>