/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2004, Daniel Stenberg, <daniel@haxx.se>, et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at http://curl.haxx.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * * $Id: hostip4.c,v 1.12 2004/10/06 07:52:20 bagder Exp $ ***************************************************************************/ #include "setup.h" #include <string.h> #include <errno.h> #define _REENTRANT #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__) #include <malloc.h> #else #ifdef HAVE_SYS_TYPES_H #include <sys/types.h> #endif #ifdef HAVE_SYS_SOCKET_H #include <sys/socket.h> #endif #ifdef HAVE_NETINET_IN_H #include <netinet/in.h> #endif #ifdef HAVE_NETDB_H #include <netdb.h> #endif #ifdef HAVE_ARPA_INET_H #include <arpa/inet.h> #endif #ifdef HAVE_STDLIB_H #include <stdlib.h> /* required for free() prototypes */ #endif #ifdef HAVE_UNISTD_H #include <unistd.h> /* for the close() proto */ #endif #ifdef VMS #include <in.h> #include <inet.h> #include <stdlib.h> #endif #endif #ifdef HAVE_SETJMP_H #include <setjmp.h> #endif #ifdef WIN32 #include <process.h> #endif #if (defined(NETWARE) && defined(__NOVELL_LIBC__)) #undef in_addr_t #define in_addr_t unsigned long #endif #include "urldata.h" #include "sendf.h" #include "hostip.h" #include "hash.h" #include "share.h" #include "strerror.h" #include "url.h" #define _MPRINTF_REPLACE /* use our functions only */ #include <curl/mprintf.h> #if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL) #include "inet_ntoa_r.h" #endif #include "memory.h" /* The last #include file should be: */ #include "memdebug.h" /*********************************************************************** * Only for plain-ipv4 builds **********************************************************************/ #ifdef CURLRES_IPV4 /* plain ipv4 code coming up */ /* * This is a function for freeing name information in a protocol independent * way. */ void Curl_freeaddrinfo(Curl_addrinfo *ai) { Curl_addrinfo *next; /* walk over the list and free all entries */ while(ai) { next = ai->ai_next; free(ai); ai = next; } } /* * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've * been set and returns TRUE if they are OK. */ bool Curl_ipvalid(struct SessionHandle *data) { if(data->set.ip_version == CURL_IPRESOLVE_V6) /* an ipv6 address was requested and we can't get/use one */ return FALSE; return TRUE; /* OK, proceed */ } struct namebuf { struct hostent hostentry; char *h_addr_list[2]; struct in_addr addrentry; char h_name[16]; /* 123.123.123.123 = 15 letters is maximum */ }; /* * Curl_ip2addr() takes a 32bit ipv4 internet address as input parameter * together with a pointer to the string version of the address, and it * returns a Curl_addrinfo chain filled in correctly with information for this * address/host. * * The input parameters ARE NOT checked for validity but they are expected * to have been checked already when this is called. */ Curl_addrinfo *Curl_ip2addr(in_addr_t num, char *hostname, int port) { Curl_addrinfo *ai; struct hostent *h; struct in_addr *addrentry; struct namebuf buffer; struct namebuf *buf = &buffer; h = &buf->hostentry; h->h_addr_list = &buf->h_addr_list[0]; addrentry = &buf->addrentry; addrentry->s_addr = num; h->h_addr_list[0] = (char*)addrentry; h->h_addr_list[1] = NULL; h->h_addrtype = AF_INET; h->h_length = sizeof(*addrentry); h->h_name = &buf->h_name[0]; h->h_aliases = NULL; /* Now store the dotted version of the address */ snprintf((char *)h->h_name, 16, "%s", hostname); ai = Curl_he2ai(h, port); return ai; } #ifdef CURLRES_SYNCH /* the functions below are for synchronous resolves */ /* * Curl_getaddrinfo() - the ipv4 synchronous version. * * The original code to this function was once stolen from the Dancer source * code, written by Bjorn Reese, it has since been patched and modified * considerably. * * gethostbyname_r() is the thread-safe version of the gethostbyname() * function. When we build for plain IPv4, we attempt to use this * function. There are _three_ different gethostbyname_r() versions, and we * detect which one this platform supports in the configure script and set up * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME * has the corresponding rules. This is primarily on *nix. Note that some unix * flavours have thread-safe versions of the plain gethostbyname() etc. * */ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, char *hostname, int port, int *waitp) { Curl_addrinfo *ai = NULL; struct hostent *h = NULL; in_addr_t in; struct SessionHandle *data = conn->data; struct hostent *buf = NULL; (void)port; /* unused in IPv4 code */ *waitp = 0; /* don't wait, we act synchronously */ in=inet_addr(hostname); if (in != CURL_INADDR_NONE) { /* This is a dotted IP address 123.123.123.123-style */ return Curl_ip2addr(in, hostname, port); } #if defined(HAVE_GETHOSTBYNAME_R) /* * gethostbyname_r() is the preferred resolve function for many platforms. * Since there are three different versions of it, the following code is * somewhat #ifdef-ridden. */ else { int h_errnop; int res=ERANGE; buf = (struct hostent *)calloc(CURL_HOSTENT_SIZE, 1); if(!buf) return NULL; /* major failure */ /* * The clearing of the buffer is a workaround for a gethostbyname_r bug in * qnx nto and it is also _required_ for some of these functions on some * platforms. */ #ifdef HAVE_GETHOSTBYNAME_R_5 /* Solaris, IRIX and more */ (void)res; /* prevent compiler warning */ h = gethostbyname_r(hostname, (struct hostent *)buf, (char *)buf + sizeof(struct hostent), CURL_HOSTENT_SIZE - sizeof(struct hostent), &h_errnop); /* If the buffer is too small, it returns NULL and sets errno to * ERANGE. The errno is thread safe if this is compiled with * -D_REENTRANT as then the 'errno' variable is a macro defined to get * used properly for threads. */ if(h) { ; } else #endif /* HAVE_GETHOSTBYNAME_R_5 */ #ifdef HAVE_GETHOSTBYNAME_R_6 /* Linux */ res=gethostbyname_r(hostname, (struct hostent *)buf, (char *)buf + sizeof(struct hostent), CURL_HOSTENT_SIZE - sizeof(struct hostent), &h, /* DIFFERENCE */ &h_errnop); /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a * sudden this function returns EAGAIN if the given buffer size is too * small. Previous versions are known to return ERANGE for the same * problem. * * This wouldn't be such a big problem if older versions wouldn't * sometimes return EAGAIN on a common failure case. Alas, we can't * assume that EAGAIN *or* ERANGE means ERANGE for any given version of * glibc. * * For now, we do that and thus we may call the function repeatedly and * fail for older glibc versions that return EAGAIN, until we run out of * buffer size (step_size grows beyond CURL_HOSTENT_SIZE). * * If anyone has a better fix, please tell us! * * ------------------------------------------------------------------- * * On October 23rd 2003, Dan C dug up more details on the mysteries of * gethostbyname_r() in glibc: * * In glibc 2.2.5 the interface is different (this has also been * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32 * (shipped/upgraded by Redhat 7.2) don't show this behavior! * * In this "buggy" version, the return code is -1 on error and 'errno' * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a * thread-safe variable. */ if(!h) /* failure */ #endif/* HAVE_GETHOSTBYNAME_R_6 */ #ifdef HAVE_GETHOSTBYNAME_R_3 /* AIX, Digital Unix/Tru64, HPUX 10, more? */ /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of * the plain fact that it does not return unique full buffers on each * call, but instead several of the pointers in the hostent structs will * point to the same actual data! This have the unfortunate down-side that * our caching system breaks down horribly. Luckily for us though, AIX 4.3 * and more recent versions have a "completely thread-safe"[*] libc where * all the data is stored in thread-specific memory areas making calls to * the plain old gethostbyname() work fine even for multi-threaded * programs. * * This AIX 4.3 or later detection is all made in the configure script. * * Troels Walsted Hansen helped us work this out on March 3rd, 2003. * * [*] = much later we've found out that it isn't at all "completely * thread-safe", but at least the gethostbyname() function is. */ if(CURL_HOSTENT_SIZE >= (sizeof(struct hostent)+sizeof(struct hostent_data))) { /* August 22nd, 2000: Albert Chin-A-Young brought an updated version * that should work! September 20: Richard Prescott worked on the buffer * size dilemma. */ res = gethostbyname_r(hostname, (struct hostent *)buf, (struct hostent_data *)((char *)buf + sizeof(struct hostent))); h_errnop= errno; /* we don't deal with this, but set it anyway */ } else res = -1; /* failure, too smallish buffer size */ if(!res) { /* success */ h = buf; /* result expected in h */ /* This is the worst kind of the different gethostbyname_r() interfaces. * Since we don't know how big buffer this particular lookup required, * we can't realloc down the huge alloc without doing closer analysis of * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every * name lookup. Fixing this would require an extra malloc() and then * calling Curl_addrinfo_copy() that subsequent realloc()s down the new * memory area to the actually used amount. */ } else #endif /* HAVE_GETHOSTBYNAME_R_3 */ { infof(data, "gethostbyname_r(2) failed for %s\n", hostname); h = NULL; /* set return code to NULL */ free(buf); } #else /* HAVE_GETHOSTBYNAME_R */ /* * Here is code for platforms that don't have gethostbyname_r() or for * which the gethostbyname() is the preferred() function. */ else { h = gethostbyname(hostname); if (!h) infof(data, "gethostbyname(2) failed for %s\n", hostname); #endif /*HAVE_GETHOSTBYNAME_R */ } if(h) { ai = Curl_he2ai(h, port); if (buf) /* used a *_r() function */ free(buf); } return ai; } #endif /* CURLRES_SYNCH */ /* * Curl_he2ai() translates from a hostent struct to a Curl_addrinfo struct. * The Curl_addrinfo is meant to work like the addrinfo struct does for IPv6 * stacks, but for all hosts and environments. struct Curl_addrinfo { int ai_flags; int ai_family; int ai_socktype; int ai_protocol; size_t ai_addrlen; struct sockaddr *ai_addr; char *ai_canonname; struct addrinfo *ai_next; }; struct hostent { char *h_name; * official name of host * char **h_aliases; * alias list * int h_addrtype; * host address type * int h_length; * length of address * char **h_addr_list; * list of addresses * } #define h_addr h_addr_list[0] * for backward compatibility * */ Curl_addrinfo *Curl_he2ai(struct hostent *he, int port) { Curl_addrinfo *ai; Curl_addrinfo *prevai = NULL; Curl_addrinfo *firstai = NULL; struct sockaddr_in *addr; int i; struct in_addr *curr; if(!he) /* no input == no output! */ return NULL; for(i=0; (curr = (struct in_addr *)he->h_addr_list[i]); i++) { ai = calloc(1, sizeof(Curl_addrinfo) + sizeof(struct sockaddr_in)); if(!ai) break; if(!firstai) /* store the pointer we want to return from this function */ firstai = ai; if(prevai) /* make the previous entry point to this */ prevai->ai_next = ai; ai->ai_family = AF_INET; /* we only support this */ ai->ai_socktype = SOCK_STREAM; /* we only support this */ ai->ai_addrlen = sizeof(struct sockaddr_in); /* make the ai_addr point to the address immediately following this struct and use that area to store the address */ ai->ai_addr = (struct sockaddr *) ((char*)ai + sizeof(Curl_addrinfo)); /* leave the rest of the struct filled with zero */ addr = (struct sockaddr_in *)ai->ai_addr; /* storage area for this info */ memcpy((char *)&(addr->sin_addr), curr, sizeof(struct in_addr)); addr->sin_family = he->h_addrtype; addr->sin_port = htons((unsigned short)port); prevai = ai; } return firstai; } #endif /* CURLRES_IPV4 */