From 4e3976711dec26ba1f462f19c4b865dea3dbe4d7 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 18 Jan 2007 22:38:13 +0000 Subject: [PATCH] A working name resolution framework --- src/config.h | 4 +- src/core/resolv.c | 141 ++++++++++++++++++++++++++++++++------ src/include/gpxe/resolv.h | 47 +++++++++++++ src/include/resolv.h | 16 ----- src/net/tcp/http.c | 14 ++-- src/net/udp/dns.c | 7 ++ src/usr/dhcpmgmt.c | 12 +++- 7 files changed, 192 insertions(+), 49 deletions(-) create mode 100644 src/include/gpxe/resolv.h delete mode 100644 src/include/resolv.h diff --git a/src/config.h b/src/config.h index 4c1af385..1e75f461 100644 --- a/src/config.h +++ b/src/config.h @@ -72,7 +72,7 @@ #define DOWNLOAD_PROTO_TFTP /* Trivial File Transfer Protocol */ #undef DOWNLOAD_PROTO_NFS /* Network File System */ -#undef DOWNLOAD_PROTO_HTTP /* Hypertext Transfer Protocol */ +#define DOWNLOAD_PROTO_HTTP /* Hypertext Transfer Protocol */ #undef DOWNLOAD_PROTO_TFTM /* Multicast Trivial File Transfer Protocol */ #undef DOWNLOAD_PROTO_SLAM /* Scalable Local Area Multicast */ #undef DOWNLOAD_PROTO_FSP /* FSP? */ @@ -85,7 +85,7 @@ * */ -#undef DNS_RESOLVER /* DNS resolver */ +#define DNS_RESOLVER /* DNS resolver */ #undef NMB_RESOLVER /* NMB resolver */ /* @END general.h */ diff --git a/src/core/resolv.c b/src/core/resolv.c index eb01a309..61bdfb09 100644 --- a/src/core/resolv.c +++ b/src/core/resolv.c @@ -1,33 +1,134 @@ -#include "resolv.h" - -static struct resolver resolvers[0] - __table_start ( struct resolver, resolver ); -static struct resolver resolvers_end[0] - __table_end ( struct resolver, resolver ); - /* - * Resolve a name (which may be just a dotted quad IP address) to an - * IP address. + * Copyright (C) 2007 Michael Brown . + * + * 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. + */ + +#include +#include +#include +#include +#include +#include + +/** @file + * + * Name resolution * */ -int resolv ( struct in_addr *address, const char *name ) { + +static struct async_operations resolv_async_operations; + +/** Registered name resolvers */ +static struct resolver resolvers[0] + __table_start ( struct resolver, resolvers ); +static struct resolver resolvers_end[0] + __table_end ( struct resolver, resolvers ); + +/** + * Start name resolution + * + * @v name Host name to resolve + * @v sa Socket address to fill in + * @v parent Parent asynchronous operation + * @ret rc Return status code + */ +int resolv ( const char *name, struct sockaddr *sa, struct async *parent ) { + struct resolution *resolution; struct resolver *resolver; + struct sockaddr_in *sin = ( struct sockaddr_in * ) sa; + struct in_addr in; + int rc = -ENXIO; + + /* Allocate and populate resolution structure */ + resolution = malloc ( sizeof ( *resolution ) ); + if ( ! resolution ) + return -ENOMEM; + async_init ( &resolution->async, &resolv_async_operations, parent ); /* Check for a dotted quad IP address first */ - if ( inet_aton ( name, address ) ) { - DBG ( "RESOLV saw valid IP address %s\n", name ); - return 1; + if ( inet_aton ( name, &in ) != 0 ) { + DBGC ( resolution, "RESOLV %p saw valid IP address %s\n", + resolution, name ); + sin->sin_family = AF_INET; + sin->sin_addr = in; + async_done ( &resolution->async, 0 ); + return 0; } - /* Try any compiled-in name resolution modules */ + /* Start up all resolvers */ for ( resolver = resolvers ; resolver < resolvers_end ; resolver++ ) { - if ( resolver->resolv ( address, name ) ) { - DBG ( "RESOLV resolved \"%s\" to %@ using %s\n", - name, address->s_addr, resolver->name ); - return 1; + if ( ( rc = resolver->resolv ( name, sa, + &resolution->async ) ) != 0 ) { + DBGC ( resolution, "RESOLV %p could not start %s: " + "%s\n", resolution, resolver->name, + strerror ( rc ) ); + /* Continue to try other resolvers */ + continue; } + (resolution->pending)++; + } + if ( ! resolution->pending ) + goto err; + + return 0; + + err: + async_uninit ( &resolution->async ); + free ( resolution ); + return rc; +} + +/** + * Handle child name resolution completion + * + * @v async Name resolution asynchronous operation + * @v signal SIGCHLD + */ +static void resolv_sigchld ( struct async *async, + enum signal signal __unused ) { + struct resolution *resolution = + container_of ( async, struct resolution, async ); + int rc; + + /* If this child succeeded, kill all the others and return */ + async_wait ( async, &rc, 1 ); + if ( rc == 0 ) { + async_signal_children ( async, SIGKILL ); + async_done ( async, 0 ); + return; } - DBG ( "RESOLV failed to resolve %s\n", name ); - return 0; + /* If we have no children left, return failure */ + if ( --(resolution->pending) == 0 ) + async_done ( async, -ENXIO ); } + +/** + * Free name resolution structure + * + * @v async Asynchronous operation + */ +static void resolv_reap ( struct async *async ) { + free ( container_of ( async, struct resolution, async ) ); +} + +/** Name resolution asynchronous operations */ +static struct async_operations resolv_async_operations = { + .reap = resolv_reap, + .signal = { + [SIGCHLD] = resolv_sigchld, + }, +}; diff --git a/src/include/gpxe/resolv.h b/src/include/gpxe/resolv.h new file mode 100644 index 00000000..71364012 --- /dev/null +++ b/src/include/gpxe/resolv.h @@ -0,0 +1,47 @@ +#ifndef _GPXE_RESOLV_H +#define _GPXE_RESOLV_H + +/** @file + * + * Name resolution + * + */ + +struct sockaddr; + +#include +#include + +/** A name resolver */ +struct resolver { + /** Name of this resolver (e.g. "DNS") */ + const char *name; + /** Start name resolution + * + * @v name Host name to resolve + * @v sa Socket address to fill in + * @v parent Parent asynchronous operation + * @ret rc Return status code + * + * The asynchronous process must be prepared to accept + * SIGKILL. + */ + int ( * resolv ) ( const char *name, struct sockaddr *sa, + struct async *parent ); +}; + +/** A name resolution in progress */ +struct resolution { + /** Asynchronous operation */ + struct async async; + /** Numner of active child resolvers */ + unsigned int pending; +}; + +/** Register as a name resolver */ +#define __resolver __table ( struct resolver, resolvers, 01 ) + +extern int resolv ( const char *name, struct sockaddr *sa, + struct async *parent ); + +#endif /* _GPXE_RESOLV_H */ diff --git a/src/include/resolv.h b/src/include/resolv.h deleted file mode 100644 index 714d39ef..00000000 --- a/src/include/resolv.h +++ /dev/null @@ -1,16 +0,0 @@ -#ifndef RESOLV_H -#define RESOLV_H - -#include -#include - -struct resolver { - const char *name; - int ( * resolv ) ( struct in_addr *address, const char *name ); -}; - -#define __resolver __table ( struct resolver, resolver, 01 ) - -extern int resolv ( struct in_addr *address, const char *name ); - -#endif /* RESOLV_H */ diff --git a/src/net/tcp/http.c b/src/net/tcp/http.c index 04e8f9a1..87f6eee2 100644 --- a/src/net/tcp/http.c +++ b/src/net/tcp/http.c @@ -35,6 +35,7 @@ #include #include #include +#include #include static struct async_operations http_async_operations; @@ -391,17 +392,12 @@ int http_get ( struct uri *uri, struct buffer *buffer, struct async *parent ) { http->buffer = buffer; async_init ( &http->async, &http_async_operations, parent ); - -#warning "Quick name resolution hack" - extern int dns_resolv ( const char *name, - struct sockaddr *sa, - struct async *parent ); - - if ( ( rc = dns_resolv ( uri->host, &http->server, - &http->async ) ) != 0 ) + /* Start name resolution. The download proper will start when + * name resolution completes. + */ + if ( ( rc = resolv ( uri->host, &http->server, &http->async ) ) != 0 ) goto err; - return 0; err: diff --git a/src/net/udp/dns.c b/src/net/udp/dns.c index 872e3b29..a5b658c2 100644 --- a/src/net/udp/dns.c +++ b/src/net/udp/dns.c @@ -26,6 +26,7 @@ #include #include #include +#include #include /** @file @@ -468,3 +469,9 @@ int dns_resolv ( const char *name, struct sockaddr *sa, free ( dns ); return rc; } + +/** DNS name resolver */ +struct resolver dns_resolver __resolver = { + .name = "DNS", + .resolv = dns_resolv, +}; diff --git a/src/usr/dhcpmgmt.c b/src/usr/dhcpmgmt.c index 6f030274..42a0f2b7 100644 --- a/src/usr/dhcpmgmt.c +++ b/src/usr/dhcpmgmt.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -33,6 +34,9 @@ * */ +/* Avoid dragging in dns.o */ +struct in_addr nameserver; + /** * Configure network device via DHCP * @@ -42,8 +46,8 @@ int dhcp ( struct net_device *netdev ) { static struct dhcp_option_block *dhcp_options = NULL; struct dhcp_session dhcp; - struct in_addr address = { htonl ( 0 ) }; - struct in_addr netmask = { htonl ( 0 ) }; + struct in_addr address = { 0 }; + struct in_addr netmask = { 0 }; struct in_addr gateway = { INADDR_NONE }; struct async async; int rc; @@ -90,5 +94,9 @@ int dhcp ( struct net_device *netdev ) { return rc; } + /* Retrieve other DHCP options that we care about */ + find_dhcp_ipv4_option ( dhcp_options, DHCP_DNS_SERVERS, + &nameserver ); + return 0; }