From ca67b09c015d4af3ae3cce12aa72e60941dbb8b5 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 18:29:52 +0200 Subject: Adding debian version 2.06-13+deb12u1. Signed-off-by: Daniel Baumann --- debian/grub-extras/disabled/gpxe/src/net/udp/dns.c | 602 +++++++++++++++++++++ 1 file changed, 602 insertions(+) create mode 100644 debian/grub-extras/disabled/gpxe/src/net/udp/dns.c (limited to 'debian/grub-extras/disabled/gpxe/src/net/udp/dns.c') diff --git a/debian/grub-extras/disabled/gpxe/src/net/udp/dns.c b/debian/grub-extras/disabled/gpxe/src/net/udp/dns.c new file mode 100644 index 0000000..3bb6829 --- /dev/null +++ b/debian/grub-extras/disabled/gpxe/src/net/udp/dns.c @@ -0,0 +1,602 @@ +/* + * Copyright (C) 2006 Michael Brown . + * + * Portions copyright (C) 2004 Anselm M. Hoffmeister + * . + * + * This program 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 of the + * License, or any later version. + * + * This program 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 this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/** @file + * + * DNS protocol + * + */ + +FEATURE ( FEATURE_PROTOCOL, "DNS", DHCP_EB_FEATURE_DNS, 1 ); + +/** The DNS server */ +static struct sockaddr_tcpip nameserver = { + .st_port = htons ( DNS_PORT ), +}; + +/** The local domain */ +static char *localdomain; + +/** A DNS request */ +struct dns_request { + /** Reference counter */ + struct refcnt refcnt; + /** Name resolution interface */ + struct resolv_interface resolv; + /** Data transfer interface */ + struct xfer_interface socket; + /** Retry timer */ + struct retry_timer timer; + + /** Socket address to fill in with resolved address */ + struct sockaddr sa; + /** Current query packet */ + struct dns_query query; + /** Location of query info structure within current packet + * + * The query info structure is located immediately after the + * compressed name. + */ + struct dns_query_info *qinfo; + /** Recursion counter */ + unsigned int recursion; +}; + +/** + * Mark DNS request as complete + * + * @v dns DNS request + * @v rc Return status code + */ +static void dns_done ( struct dns_request *dns, int rc ) { + + /* Stop the retry timer */ + stop_timer ( &dns->timer ); + + /* Close data transfer interface */ + xfer_nullify ( &dns->socket ); + xfer_close ( &dns->socket, rc ); + + /* Mark name resolution as complete */ + resolv_done ( &dns->resolv, &dns->sa, rc ); +} + +/** + * Compare DNS reply name against the query name from the original request + * + * @v dns DNS request + * @v reply DNS reply + * @v rname Reply name + * @ret zero Names match + * @ret non-zero Names do not match + */ +static int dns_name_cmp ( struct dns_request *dns, + const struct dns_header *reply, + const char *rname ) { + const char *qname = dns->query.payload; + int i; + + while ( 1 ) { + /* Obtain next section of rname */ + while ( ( *rname ) & 0xc0 ) { + rname = ( ( ( char * ) reply ) + + ( ntohs( *((uint16_t *)rname) ) & ~0xc000 )); + } + /* Check that lengths match */ + if ( *rname != *qname ) + return -1; + /* If length is zero, we have reached the end */ + if ( ! *qname ) + return 0; + /* Check that data matches */ + for ( i = *qname + 1; i > 0 ; i-- ) { + if ( *(rname++) != *(qname++) ) + return -1; + } + } +} + +/** + * Skip over a (possibly compressed) DNS name + * + * @v name DNS name + * @ret name Next DNS name + */ +static const char * dns_skip_name ( const char *name ) { + while ( 1 ) { + if ( ! *name ) { + /* End of name */ + return ( name + 1); + } + if ( *name & 0xc0 ) { + /* Start of a compressed name */ + return ( name + 2 ); + } + /* Uncompressed name portion */ + name += *name + 1; + } +} + +/** + * Find an RR in a reply packet corresponding to our query + * + * @v dns DNS request + * @v reply DNS reply + * @ret rr DNS RR, or NULL if not found + */ +static union dns_rr_info * dns_find_rr ( struct dns_request *dns, + const struct dns_header *reply ) { + int i, cmp; + const char *p = ( ( char * ) reply ) + sizeof ( struct dns_header ); + union dns_rr_info *rr_info; + + /* Skip over the questions section */ + for ( i = ntohs ( reply->qdcount ) ; i > 0 ; i-- ) { + p = dns_skip_name ( p ) + sizeof ( struct dns_query_info ); + } + + /* Process the answers section */ + for ( i = ntohs ( reply->ancount ) ; i > 0 ; i-- ) { + cmp = dns_name_cmp ( dns, reply, p ); + p = dns_skip_name ( p ); + rr_info = ( ( union dns_rr_info * ) p ); + if ( cmp == 0 ) + return rr_info; + p += ( sizeof ( rr_info->common ) + + ntohs ( rr_info->common.rdlength ) ); + } + + return NULL; +} + +/** + * Append DHCP domain name if available and name is not fully qualified + * + * @v string Name as a NUL-terminated string + * @ret fqdn Fully-qualified domain name, malloc'd copy + * + * The caller must free fqdn which is allocated even if the name is already + * fully qualified. + */ +static char * dns_qualify_name ( const char *string ) { + char *fqdn; + + /* Leave unchanged if already fully-qualified or no local domain */ + if ( ( ! localdomain ) || ( strchr ( string, '.' ) != 0 ) ) + return strdup ( string ); + + /* Append local domain to name */ + return grub_xasprintf ( "%s.%s", string, localdomain ); +} + +/** + * Convert a standard NUL-terminated string to a DNS name + * + * @v string Name as a NUL-terminated string + * @v buf Buffer in which to place DNS name + * @ret next Byte following constructed DNS name + * + * DNS names consist of "element" pairs. + */ +static char * dns_make_name ( const char *string, char *buf ) { + char *length_byte = buf++; + char c; + + while ( ( c = *(string++) ) ) { + if ( c == '.' ) { + *length_byte = buf - length_byte - 1; + length_byte = buf; + } + *(buf++) = c; + } + *length_byte = buf - length_byte - 1; + *(buf++) = '\0'; + return buf; +} + +/** + * Convert an uncompressed DNS name to a NUL-terminated string + * + * @v name DNS name + * @ret string NUL-terminated string + * + * Produce a printable version of a DNS name. Used only for debugging. + */ +static inline char * dns_unmake_name ( char *name ) { + char *p; + unsigned int len; + + p = name; + while ( ( len = *p ) ) { + *(p++) = '.'; + p += len; + } + + return name + 1; +} + +/** + * Decompress a DNS name + * + * @v reply DNS replay + * @v name DNS name + * @v buf Buffer into which to decompress DNS name + * @ret next Byte following decompressed DNS name + */ +static char * dns_decompress_name ( const struct dns_header *reply, + const char *name, char *buf ) { + int i, len; + + do { + /* Obtain next section of name */ + while ( ( *name ) & 0xc0 ) { + name = ( ( char * ) reply + + ( ntohs ( *((uint16_t *)name) ) & ~0xc000 ) ); + } + /* Copy data */ + len = *name; + for ( i = len + 1 ; i > 0 ; i-- ) { + *(buf++) = *(name++); + } + } while ( len ); + return buf; +} + +/** + * Send next packet in DNS request + * + * @v dns DNS request + */ +static int dns_send_packet ( struct dns_request *dns ) { + static unsigned int qid = 0; + size_t qlen; + + /* Increment query ID */ + dns->query.dns.id = htons ( ++qid ); + + DBGC ( dns, "DNS %p sending query ID %d\n", dns, qid ); + + /* Start retransmission timer */ + start_timer ( &dns->timer ); + + /* Send the data */ + qlen = ( ( ( void * ) dns->qinfo ) - ( ( void * ) &dns->query ) + + sizeof ( dns->qinfo ) ); + return xfer_deliver_raw ( &dns->socket, &dns->query, qlen ); +} + +/** + * Handle DNS retransmission timer expiry + * + * @v timer Retry timer + * @v fail Failure indicator + */ +static void dns_timer_expired ( struct retry_timer *timer, int fail ) { + struct dns_request *dns = + container_of ( timer, struct dns_request, timer ); + + if ( fail ) { + dns_done ( dns, -ETIMEDOUT ); + } else { + dns_send_packet ( dns ); + } +} + +/** + * Receive new data + * + * @v socket UDP socket + * @v data DNS reply + * @v len Length of DNS reply + * @ret rc Return status code + */ +static int dns_xfer_deliver_raw ( struct xfer_interface *socket, + const void *data, size_t len ) { + struct dns_request *dns = + container_of ( socket, struct dns_request, socket ); + const struct dns_header *reply = data; + union dns_rr_info *rr_info; + struct sockaddr_in *sin; + unsigned int qtype = dns->qinfo->qtype; + + /* Sanity check */ + if ( len < sizeof ( *reply ) ) { + DBGC ( dns, "DNS %p received underlength packet length %zd\n", + dns, len ); + return -EINVAL; + } + + /* Check reply ID matches query ID */ + if ( reply->id != dns->query.dns.id ) { + DBGC ( dns, "DNS %p received unexpected reply ID %d " + "(wanted %d)\n", dns, ntohs ( reply->id ), + ntohs ( dns->query.dns.id ) ); + return -EINVAL; + } + + DBGC ( dns, "DNS %p received reply ID %d\n", dns, ntohs ( reply->id )); + + /* Stop the retry timer. After this point, each code path + * must either restart the timer by calling dns_send_packet(), + * or mark the DNS operation as complete by calling + * dns_done() + */ + stop_timer ( &dns->timer ); + + /* Search through response for useful answers. Do this + * multiple times, to take advantage of useful nameservers + * which send us e.g. the CNAME *and* the A record for the + * pointed-to name. + */ + while ( ( rr_info = dns_find_rr ( dns, reply ) ) ) { + switch ( rr_info->common.type ) { + + case htons ( DNS_TYPE_A ): + + /* Found the target A record */ + DBGC ( dns, "DNS %p found address %s\n", + dns, inet_ntoa ( rr_info->a.in_addr ) ); + sin = ( struct sockaddr_in * ) &dns->sa; + sin->sin_family = AF_INET; + sin->sin_addr = rr_info->a.in_addr; + + /* Mark operation as complete */ + dns_done ( dns, 0 ); + return 0; + + case htons ( DNS_TYPE_CNAME ): + + /* Found a CNAME record; update query and recurse */ + DBGC ( dns, "DNS %p found CNAME\n", dns ); + dns->qinfo = ( void * ) dns_decompress_name ( reply, + rr_info->cname.cname, + dns->query.payload ); + dns->qinfo->qtype = htons ( DNS_TYPE_A ); + dns->qinfo->qclass = htons ( DNS_CLASS_IN ); + + /* Terminate the operation if we recurse too far */ + if ( ++dns->recursion > DNS_MAX_CNAME_RECURSION ) { + DBGC ( dns, "DNS %p recursion exceeded\n", + dns ); + dns_done ( dns, -ELOOP ); + return 0; + } + break; + + default: + DBGC ( dns, "DNS %p got unknown record type %d\n", + dns, ntohs ( rr_info->common.type ) ); + break; + } + } + + /* Determine what to do next based on the type of query we + * issued and the reponse we received + */ + switch ( qtype ) { + + case htons ( DNS_TYPE_A ): + /* We asked for an A record and got nothing; + * try the CNAME. + */ + DBGC ( dns, "DNS %p found no A record; trying CNAME\n", dns ); + dns->qinfo->qtype = htons ( DNS_TYPE_CNAME ); + dns_send_packet ( dns ); + return 0; + + case htons ( DNS_TYPE_CNAME ): + /* We asked for a CNAME record. If we got a response + * (i.e. if the next A query is already set up), then + * issue it, otherwise abort. + */ + if ( dns->qinfo->qtype == htons ( DNS_TYPE_A ) ) { + dns_send_packet ( dns ); + return 0; + } else { + DBGC ( dns, "DNS %p found no CNAME record\n", dns ); + dns_done ( dns, -ENXIO ); + return 0; + } + + default: + assert ( 0 ); + dns_done ( dns, -EINVAL ); + return 0; + } +} + +/** + * Receive new data + * + * @v socket UDP socket + * @v rc Reason for close + */ +static void dns_xfer_close ( struct xfer_interface *socket, int rc ) { + struct dns_request *dns = + container_of ( socket, struct dns_request, socket ); + + if ( ! rc ) + rc = -ECONNABORTED; + + dns_done ( dns, rc ); +} + +/** DNS socket operations */ +static struct xfer_interface_operations dns_socket_operations = { + .close = dns_xfer_close, + .vredirect = xfer_vreopen, + .window = unlimited_xfer_window, + .alloc_iob = default_xfer_alloc_iob, + .deliver_iob = xfer_deliver_as_raw, + .deliver_raw = dns_xfer_deliver_raw, +}; + +/** + * Resolve name using DNS + * + * @v resolv Name resolution interface + * @v name Name to resolve + * @v sa Socket address to fill in + * @ret rc Return status code + */ +static int dns_resolv ( struct resolv_interface *resolv, + const char *name, struct sockaddr *sa ) { + struct dns_request *dns; + char *fqdn; + int rc; + + /* Fail immediately if no DNS servers */ + if ( ! nameserver.st_family ) { + DBG ( "DNS not attempting to resolve \"%s\": " + "no DNS servers\n", name ); + rc = -ENXIO; + goto err_no_nameserver; + } + + /* Ensure fully-qualified domain name if DHCP option was given */ + fqdn = dns_qualify_name ( name ); + if ( ! fqdn ) { + rc = -ENOMEM; + goto err_qualify_name; + } + + /* Allocate DNS structure */ + dns = zalloc ( sizeof ( *dns ) ); + if ( ! dns ) { + rc = -ENOMEM; + goto err_alloc_dns; + } + resolv_init ( &dns->resolv, &null_resolv_ops, &dns->refcnt ); + xfer_init ( &dns->socket, &dns_socket_operations, &dns->refcnt ); + dns->timer.expired = dns_timer_expired; + memcpy ( &dns->sa, sa, sizeof ( dns->sa ) ); + + /* Create query */ + dns->query.dns.flags = htons ( DNS_FLAG_QUERY | DNS_FLAG_OPCODE_QUERY | + DNS_FLAG_RD ); + dns->query.dns.qdcount = htons ( 1 ); + dns->qinfo = ( void * ) dns_make_name ( fqdn, dns->query.payload ); + dns->qinfo->qtype = htons ( DNS_TYPE_A ); + dns->qinfo->qclass = htons ( DNS_CLASS_IN ); + + /* Open UDP connection */ + if ( ( rc = xfer_open_socket ( &dns->socket, SOCK_DGRAM, + ( struct sockaddr * ) &nameserver, + NULL ) ) != 0 ) { + DBGC ( dns, "DNS %p could not open socket: %s\n", + dns, strerror ( rc ) ); + goto err_open_socket; + } + + /* Send first DNS packet */ + dns_send_packet ( dns ); + + /* Attach parent interface, mortalise self, and return */ + resolv_plug_plug ( &dns->resolv, resolv ); + ref_put ( &dns->refcnt ); + free ( fqdn ); + return 0; + + err_open_socket: + err_alloc_dns: + ref_put ( &dns->refcnt ); + err_qualify_name: + free ( fqdn ); + err_no_nameserver: + return rc; +} + +/** DNS name resolver */ +struct resolver dns_resolver __resolver ( RESOLV_NORMAL ) = { + .name = "DNS", + .resolv = dns_resolv, +}; + +/****************************************************************************** + * + * Settings + * + ****************************************************************************** + */ + +/** DNS server setting */ +struct setting dns_setting __setting = { + .name = "dns", + .description = "DNS server", + .tag = DHCP_DNS_SERVERS, + .type = &setting_type_ipv4, +}; + +/** Domain name setting */ +struct setting domain_setting __setting = { + .name = "domain", + .description = "Local domain", + .tag = DHCP_DOMAIN_NAME, + .type = &setting_type_string, +}; + +/** + * Apply DNS settings + * + * @ret rc Return status code + */ +static int apply_dns_settings ( void ) { + struct sockaddr_in *sin_nameserver = + ( struct sockaddr_in * ) &nameserver; + int len; + + if ( ( len = fetch_ipv4_setting ( NULL, &dns_setting, + &sin_nameserver->sin_addr ) ) >= 0 ){ + sin_nameserver->sin_family = AF_INET; + DBG ( "DNS using nameserver %s\n", + inet_ntoa ( sin_nameserver->sin_addr ) ); + } + + /* Get local domain DHCP option */ + if ( ( len = fetch_string_setting_copy ( NULL, &domain_setting, + &localdomain ) ) >= 0 ) + DBG ( "DNS local domain %s\n", localdomain ); + + return 0; +} + +/** DNS settings applicator */ +struct settings_applicator dns_applicator __settings_applicator = { + .apply = apply_dns_settings, +}; -- cgit v1.2.3