* cygwin.din: Export gethostbyname2.
* net.cc: define _CYGWIN_IN_H and include resolv.h. (realloc_ent): New function. (dup_ent): Call realloc_ent. (memcpy4to6): New function. (dn_length1): New function. (gethostby_helper): New function. (gethostbyname2): New function. * posix.sgml: Add gethostbyname2. * include/cygwin/version.h: Bump API minor number. * libc/minires.c (get_options): Look for "inet6" and apply bounds to "retry" and "retrans". (res_ninit): Set the default options at the beginning. (dn_expand): Fix "off by one".
This commit is contained in:
Corinna Vinschen
@ -1,7 +1,7 @@
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/* net.cc: network-related routines.
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Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
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2005, 2006, 2007 Red Hat, Inc.
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2005, 2006, 2007, 2008, 2009 Red Hat, Inc.
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This file is part of Cygwin.
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@ -43,6 +43,8 @@ details. */
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#include "cygwin/in6.h"
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#include "ifaddrs.h"
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#include "tls_pbuf.h"
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#define _CYGWIN_IN_H
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#include <resolv.h>
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extern "C"
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{
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@ -53,6 +55,9 @@ extern "C"
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int sscanf (const char *, const char *, ...);
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int cygwin_inet_aton(const char *, struct in_addr *);
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const char *cygwin_inet_ntop (int, const void *, char *, socklen_t);
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int dn_length1(const unsigned char *, const unsigned char *,
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const unsigned char *);
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} /* End of "C" section */
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const struct in6_addr in6addr_any = {{IN6ADDR_ANY_INIT}};
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@ -264,6 +269,25 @@ struct pservent
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static const char *entnames[] = {"host", "proto", "serv"};
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static unionent *
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realloc_ent (unionent *&dst, int sz)
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{
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/* Allocate the storage needed. Allocate a rounded size to attempt to force
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reuse of this buffer so that a poorly-written caller will not be using
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a freed buffer. */
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unsigned rsz = 256 * ((sz + 255) / 256);
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unionent * ptr;
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if ((ptr = (unionent *) realloc (dst, rsz)))
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dst = ptr;
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return ptr;
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}
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static inline hostent *
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realloc_ent (int sz, hostent *)
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{
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return (hostent *) realloc_ent (_my_tls.locals.hostent_buf, sz);
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}
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/* Generic "dup a {host,proto,serv}ent structure" function.
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This is complicated because we need to be able to free the
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structure at any point and we can't rely on the pointer contents
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@ -310,7 +334,7 @@ dup_ent (unionent *&dst, unionent *src, unionent::struct_type type)
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break;
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}
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/* Every *ent begins with a name. Calculate it's length. */
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/* Every *ent begins with a name. Calculate its length. */
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int namelen = strlen_round (src->name);
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sz = struct_sz + namelen;
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@ -355,13 +379,8 @@ dup_ent (unionent *&dst, unionent *src, unionent::struct_type type)
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}
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}
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/* Allocate the storage needed. Allocate a rounded size to attempt to force
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reuse of this buffer so that a poorly-written caller will not be using
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a freed buffer. */
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unsigned rsz = 256 * ((sz + 255) / 256);
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dst = (unionent *) realloc (dst, rsz);
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if (dst)
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/* Allocate the storage needed. */
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if (realloc_ent (dst, sz))
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{
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memset (dst, 0, sz);
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/* This field is common to all *ent structures but named differently
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@ -857,6 +876,287 @@ cygwin_gethostbyaddr (const char *addr, int len, int type)
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return res;
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}
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static void
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memcpy4to6 (char *dst, const u_char *src)
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{
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const unsigned int h[] = {0, 0, htonl (0xFFFF)};
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memcpy (dst, h, 12);
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memcpy (dst + 12, src, NS_INADDRSZ);
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}
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static hostent *
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gethostby_helper (const char *name, const int af, const int type,
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const int addrsize_in, const int addrsize_out)
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{
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/* Get the data from the name server */
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const int maxcount = 3;
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int old_errno, ancount = 0, anlen = 1024, msgsize = 0;
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u_char *ptr, *msg = NULL;
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int sz;
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hostent *ret;
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char *string_ptr;
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while ((anlen > msgsize) && (ancount++ < maxcount))
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{
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msgsize = anlen;
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ptr = (u_char *) realloc (msg, msgsize);
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if (ptr == NULL )
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{
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old_errno = errno;
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free (msg);
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set_errno (old_errno);
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h_errno = NETDB_INTERNAL;
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return NULL;
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}
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msg = ptr;
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anlen = res_search (name, ns_c_in, type, msg, msgsize);
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}
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if (ancount >= maxcount)
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{
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free (msg);
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h_errno = NO_RECOVERY;
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return NULL;
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}
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if (anlen < 0) /* errno and h_errno are set */
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{
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old_errno = errno;
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free (msg);
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set_errno (old_errno);
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return NULL;
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}
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u_char *eomsg = msg + anlen - 1;
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/* We scan the answer records to determine the required memory size.
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They can be corrupted and we don't fully trust that the message
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follows the standard exactly. glibc applies some checks that
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we emulate.
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The answers are copied in the hostent structure in a second scan.
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To simplify the second scan we store information as follows:
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- "class" is replaced by the compressed name size
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- the first 16 bits of the "ttl" store the expanded name size + 1
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- the last 16 bits of the "ttl" store the offset to the next valid record.
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Note that "type" is rewritten in host byte order. */
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class record {
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public:
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unsigned type: 16; // type
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unsigned complen: 16; // class or compressed length
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unsigned namelen1: 16; // expanded length (with final 0)
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unsigned next_o: 16; // offset to next valid
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unsigned size: 16; // data size
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u_char data[]; // data
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record * next () { return (record *) (((char *) this) + next_o); }
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void set_next ( record * nxt) { next_o = ((char *) nxt) - ((char *) this); }
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u_char * name () { return (u_char *) (((char *) this) - complen); }
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};
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record * anptr = NULL, * prevptr = NULL, * curptr;
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int i, alias_count = 0, string_size = 0, address_count = 0;
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int complen, namelen1 = 0, address_len = 0, antype, anclass, ansize;
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/* Get the count of answers */
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ancount = ntohs (((HEADER *) msg)->ancount);
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/* Skip the question, it was verified by res_send */
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ptr = msg + sizeof (HEADER);
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if ((complen = dn_skipname (ptr, eomsg)) < 0)
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goto corrupted;
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/* Point to the beginning of the answer section */
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ptr += complen + NS_QFIXEDSZ;
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/* Scan the answer records to determine the sizes */
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for (i = 0; i < ancount; i++, ptr = curptr->data + ansize)
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{
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if ((complen = dn_skipname (ptr, eomsg)) < 0)
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goto corrupted;
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curptr = (record *) (ptr + complen);
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antype = ntohs (curptr->type);
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anclass = ntohs (curptr->complen);
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ansize = ntohs (curptr->size);
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/* Class must be internet */
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if (anclass != ns_c_in)
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continue;
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curptr->complen = complen;
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if ((namelen1 = dn_length1 (msg, eomsg, curptr-> name())) <= 0)
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goto corrupted;
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if (antype == ns_t_cname)
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{
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alias_count++;
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string_size += namelen1;
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}
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else if (antype == type)
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{
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ansize = ntohs (curptr->size);
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if (ansize != addrsize_in)
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continue;
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if (address_count == 0)
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{
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address_len = namelen1;
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string_size += namelen1;
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}
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else if (address_len != namelen1)
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continue;
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address_count++;
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}
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/* Update the records */
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curptr->type = antype; /* Host byte order */
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curptr->namelen1 = namelen1;
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if (! anptr)
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anptr = prevptr = curptr;
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else
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{
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prevptr->set_next (curptr);
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prevptr = curptr;
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}
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}
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/* If there is no address, quit */
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if (address_count == 0)
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{
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free (msg);
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h_errno = NO_DATA;
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return NULL;
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}
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/* Determine the total size */
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sz = DWORD_round (sizeof(hostent))
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+ sizeof (char *) * (alias_count + address_count + 2)
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+ string_size
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+ address_count * addrsize_out;
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ret = realloc_ent (sz, (hostent *) NULL);
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if (! ret)
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{
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old_errno = errno;
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free (msg);
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set_errno (old_errno);
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h_errno = NETDB_INTERNAL;
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return NULL;
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}
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ret->h_addrtype = af;
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ret->h_length = addrsize_out;
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ret->h_aliases = (char **) (((char *) ret) + DWORD_round (sizeof(hostent)));
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ret->h_addr_list = ret->h_aliases + alias_count + 1;
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string_ptr = (char *) (ret->h_addr_list + address_count + 1);
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/* Rescan the answers */
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ancount = alias_count + address_count; /* Valid records */
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alias_count = address_count = 0;
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for (i = 0, curptr = anptr; i < ancount; i++, curptr = curptr->next ())
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{
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antype = curptr->type;
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if (antype == ns_t_cname)
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{
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complen = dn_expand (msg, eomsg, curptr->name (), string_ptr, string_size);
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#ifdef DEBUGGING
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if (complen != curptr->complen)
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go to debugging;
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#endif
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ret->h_aliases[alias_count++] = string_ptr;
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namelen1 = curptr->namelen1;
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string_ptr += namelen1;
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string_size -= namelen1;
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continue;
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}
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if (antype == type)
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{
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if (address_count == 0)
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{
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complen = dn_expand (msg, eomsg, curptr->name(), string_ptr, string_size);
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#ifdef DEBUGGING
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if (complen != curptr->complen)
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go to debugging;
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#endif
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ret->h_name = string_ptr;
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namelen1 = curptr->namelen1;
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string_ptr += namelen1;
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string_size -= namelen1;
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}
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ret->h_addr_list[address_count++] = string_ptr;
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if (addrsize_in != addrsize_out)
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memcpy4to6 (string_ptr, curptr->data);
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else
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memcpy (string_ptr, curptr->data, addrsize_in);
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string_ptr += addrsize_out;
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string_size -= addrsize_out;
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continue;
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}
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#ifdef DEBUGGING
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/* Should not get here */
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go to debugging;
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#endif
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}
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#ifdef DEBUGGING
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if (string_size < 0)
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go to debugging;
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#endif
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free (msg);
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ret->h_aliases[alias_count] = NULL;
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ret->h_addr_list[address_count] = NULL;
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return ret;
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corrupted:
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free (msg);
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/* Hopefully message corruption errors are temporary.
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Should it be NO_RECOVERY ? */
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h_errno = TRY_AGAIN;
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return NULL;
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#ifdef DEBUGGING
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debugging:
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system_printf ("Please debug.");
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free (msg);
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free (ret);
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h_errno = NO_RECOVERY;
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return NULL;
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#endif
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}
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/* gethostbyname2: standards? */
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extern "C" struct hostent *
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gethostbyname2 (const char *name, int af)
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{
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sig_dispatch_pending ();
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myfault efault;
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if (efault.faulted (EFAULT))
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return NULL;
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if (!(_res.options & RES_INIT))
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res_init();
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bool v4to6 = _res.options & RES_USE_INET6;
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int type, addrsize_in, addrsize_out;
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switch (af)
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{
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case AF_INET:
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addrsize_in = NS_INADDRSZ;
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addrsize_out = (v4to6) ? NS_IN6ADDRSZ : NS_INADDRSZ;
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type = ns_t_a;
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break;
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case AF_INET6:
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addrsize_in = addrsize_out = NS_IN6ADDRSZ;
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type = ns_t_aaaa;
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break;
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default:
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set_errno (EAFNOSUPPORT);
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h_errno = NETDB_INTERNAL;
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return NULL;
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}
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return gethostby_helper (name, af, type, addrsize_in, addrsize_out);
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}
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/* exported as accept: standards? */
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extern "C" int
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cygwin_accept (int fd, struct sockaddr *peer, socklen_t *len)
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@ -2486,10 +2786,6 @@ cygwin_sendmsg (int fd, const struct msghdr *msg, int flags)
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* SOFTWARE.
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*/
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#define IN6ADDRSZ 16
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#define INADDRSZ 4
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#define INT16SZ 2
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/* int
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* inet_pton4(src, dst)
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* like inet_aton() but without all the hexadecimal and shorthand.
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Reference in New Issue
Block a user