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cpython/Modules/getaddrinfo.c

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/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* "#ifdef FAITH" part is local hack for supporting IPv4-v6 translator.
*
* Issues to be discussed:
* - Thread safe-ness must be checked.
* - Return values. There are nonstandard return values defined and used
* in the source code. This is because RFC2133 is silent about which error
* code must be returned for which situation.
* - PF_UNSPEC case would be handled in getipnodebyname() with the AI_ALL flag.
*/
#if 0
#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <ctype.h>
#include <unistd.h>
#include "addrinfo.h"
#endif
#if defined(__KAME__) && defined(ENABLE_IPV6)
# define FAITH
#endif
#define SUCCESS 0
#define GAI_ANY 0
#define YES 1
#define NO 0
#ifdef FAITH
static int translate = NO;
static struct in6_addr faith_prefix = IN6ADDR_GAI_ANY_INIT;
#endif
static const char in_addrany[] = { 0, 0, 0, 0 };
static const char in6_addrany[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static const char in_loopback[] = { 127, 0, 0, 1 };
static const char in6_loopback[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
};
struct sockinet {
u_char si_len;
u_char si_family;
u_short si_port;
};
static struct gai_afd {
int a_af;
int a_addrlen;
int a_socklen;
int a_off;
const char *a_addrany;
const char *a_loopback;
} gai_afdl [] = {
#ifdef ENABLE_IPV6
#define N_INET6 0
{PF_INET6, sizeof(struct in6_addr),
sizeof(struct sockaddr_in6),
offsetof(struct sockaddr_in6, sin6_addr),
in6_addrany, in6_loopback},
#define N_INET 1
#else
#define N_INET 0
#endif
{PF_INET, sizeof(struct in_addr),
sizeof(struct sockaddr_in),
offsetof(struct sockaddr_in, sin_addr),
in_addrany, in_loopback},
{0, 0, 0, 0, NULL, NULL},
};
#ifdef ENABLE_IPV6
#define PTON_MAX 16
#else
#define PTON_MAX 4
#endif
#ifndef IN_MULTICAST
#define IN_MULTICAST(i) (((i) & 0xf0000000U) == 0xe0000000U)
#endif
#ifndef IN_EXPERIMENTAL
#define IN_EXPERIMENTAL(i) (((i) & 0xe0000000U) == 0xe0000000U)
#endif
#ifndef IN_LOOPBACKNET
#define IN_LOOPBACKNET 127
#endif
static int get_name(const char *, struct gai_afd *,
struct addrinfo **, char *, struct addrinfo *,
int);
static int get_addr(const char *, int, struct addrinfo **,
struct addrinfo *, int);
static int str_isnumber(const char *);
static const char * const ai_errlist[] = {
"success.",
"address family for hostname not supported.", /* EAI_ADDRFAMILY */
"temporary failure in name resolution.", /* EAI_AGAIN */
"invalid value for ai_flags.", /* EAI_BADFLAGS */
"non-recoverable failure in name resolution.", /* EAI_FAIL */
"ai_family not supported.", /* EAI_FAMILY */
"memory allocation failure.", /* EAI_MEMORY */
"no address associated with hostname.", /* EAI_NODATA */
"hostname nor servname provided, or not known.",/* EAI_NONAME */
"servname not supported for ai_socktype.", /* EAI_SERVICE */
"ai_socktype not supported.", /* EAI_SOCKTYPE */
"system error returned in errno.", /* EAI_SYSTEM */
"invalid value for hints.", /* EAI_BADHINTS */
"resolved protocol is unknown.", /* EAI_PROTOCOL */
"unknown error.", /* EAI_MAX */
};
#define GET_CANONNAME(ai, str) \
if (pai->ai_flags & AI_CANONNAME) {\
if (((ai)->ai_canonname = (char *)malloc(strlen(str) + 1)) != NULL) {\
strcpy((ai)->ai_canonname, (str));\
} else {\
error = EAI_MEMORY;\
goto free;\
}\
}
#ifdef HAVE_SOCKADDR_SA_LEN
#define GET_AI(ai, gai_afd, addr, port) {\
char *p;\
if (((ai) = (struct addrinfo *)malloc(sizeof(struct addrinfo) +\
((gai_afd)->a_socklen)))\
== NULL) goto free;\
memcpy(ai, pai, sizeof(struct addrinfo));\
(ai)->ai_addr = (struct sockaddr *)((ai) + 1);\
memset((ai)->ai_addr, 0, (gai_afd)->a_socklen);\
(ai)->ai_addr->sa_len = (ai)->ai_addrlen = (gai_afd)->a_socklen;\
(ai)->ai_addr->sa_family = (ai)->ai_family = (gai_afd)->a_af;\
((struct sockinet *)(ai)->ai_addr)->si_port = port;\
p = (char *)((ai)->ai_addr);\
memcpy(p + (gai_afd)->a_off, (addr), (gai_afd)->a_addrlen);\
}
#else
#define GET_AI(ai, gai_afd, addr, port) {\
char *p;\
if (((ai) = (struct addrinfo *)malloc(sizeof(struct addrinfo) +\
((gai_afd)->a_socklen)))\
== NULL) goto free;\
memcpy(ai, pai, sizeof(struct addrinfo));\
(ai)->ai_addr = (struct sockaddr *)((ai) + 1);\
memset((ai)->ai_addr, 0, (gai_afd)->a_socklen);\
(ai)->ai_addrlen = (gai_afd)->a_socklen;\
(ai)->ai_addr->sa_family = (ai)->ai_family = (gai_afd)->a_af;\
((struct sockinet *)(ai)->ai_addr)->si_port = port;\
p = (char *)((ai)->ai_addr);\
memcpy(p + (gai_afd)->a_off, (addr), (gai_afd)->a_addrlen);\
}
#endif
#define ERR(err) { error = (err); goto bad; }
const char *
gai_strerror(int ecode)
{
if (ecode < 0 || ecode > EAI_MAX)
ecode = EAI_MAX;
return ai_errlist[ecode];
}
void
freeaddrinfo(struct addrinfo *ai)
{
struct addrinfo *next;
do {
next = ai->ai_next;
if (ai->ai_canonname)
free(ai->ai_canonname);
/* no need to free(ai->ai_addr) */
free(ai);
} while ((ai = next) != NULL);
}
static int
str_isnumber(const char *p)
{
unsigned char *q = (unsigned char *)p;
while (*q) {
if (! isdigit(*q))
return NO;
q++;
}
return YES;
}
int
getaddrinfo(const char*hostname, const char*servname,
const struct addrinfo *hints, struct addrinfo **res)
{
struct addrinfo sentinel;
struct addrinfo *top = NULL;
struct addrinfo *cur;
int i, error = 0;
char pton[PTON_MAX];
struct addrinfo ai;
struct addrinfo *pai;
u_short port;
#ifdef FAITH
static int firsttime = 1;
if (firsttime) {
/* translator hack */
{
const char *q = getenv("GAI");
if (q && inet_pton(AF_INET6, q, &faith_prefix) == 1)
translate = YES;
}
firsttime = 0;
}
#endif
/* initialize file static vars */
sentinel.ai_next = NULL;
cur = &sentinel;
pai = &ai;
pai->ai_flags = 0;
pai->ai_family = PF_UNSPEC;
pai->ai_socktype = GAI_ANY;
pai->ai_protocol = GAI_ANY;
pai->ai_addrlen = 0;
pai->ai_canonname = NULL;
pai->ai_addr = NULL;
pai->ai_next = NULL;
port = GAI_ANY;
if (hostname == NULL && servname == NULL)
return EAI_NONAME;
if (hints) {
/* error check for hints */
if (hints->ai_addrlen || hints->ai_canonname ||
hints->ai_addr || hints->ai_next)
ERR(EAI_BADHINTS); /* xxx */
if (hints->ai_flags & ~AI_MASK)
ERR(EAI_BADFLAGS);
switch (hints->ai_family) {
case PF_UNSPEC:
case PF_INET:
#ifdef ENABLE_IPV6
case PF_INET6:
#endif
break;
default:
ERR(EAI_FAMILY);
}
memcpy(pai, hints, sizeof(*pai));
switch (pai->ai_socktype) {
case GAI_ANY:
switch (pai->ai_protocol) {
case GAI_ANY:
break;
case IPPROTO_UDP:
pai->ai_socktype = SOCK_DGRAM;
break;
case IPPROTO_TCP:
pai->ai_socktype = SOCK_STREAM;
break;
default:
pai->ai_socktype = SOCK_RAW;
break;
}
break;
case SOCK_RAW:
break;
case SOCK_DGRAM:
if (pai->ai_protocol != IPPROTO_UDP &&
pai->ai_protocol != GAI_ANY)
ERR(EAI_BADHINTS); /*xxx*/
pai->ai_protocol = IPPROTO_UDP;
break;
case SOCK_STREAM:
if (pai->ai_protocol != IPPROTO_TCP &&
pai->ai_protocol != GAI_ANY)
ERR(EAI_BADHINTS); /*xxx*/
pai->ai_protocol = IPPROTO_TCP;
break;
default:
ERR(EAI_SOCKTYPE);
/* unreachable */
}
}
/*
* service port
*/
if (servname) {
if (str_isnumber(servname)) {
if (pai->ai_socktype == GAI_ANY) {
/* caller accept *GAI_ANY* socktype */
pai->ai_socktype = SOCK_DGRAM;
pai->ai_protocol = IPPROTO_UDP;
}
port = htons((u_short)atoi(servname));
} else {
struct servent *sp;
const char *proto;
proto = NULL;
switch (pai->ai_socktype) {
case GAI_ANY:
proto = NULL;
break;
case SOCK_DGRAM:
proto = "udp";
break;
case SOCK_STREAM:
proto = "tcp";
break;
default:
fprintf(stderr, "panic!\n");
break;
}
if ((sp = getservbyname(servname, proto)) == NULL)
ERR(EAI_SERVICE);
port = sp->s_port;
if (pai->ai_socktype == GAI_ANY) {
if (strcmp(sp->s_proto, "udp") == 0) {
pai->ai_socktype = SOCK_DGRAM;
pai->ai_protocol = IPPROTO_UDP;
} else if (strcmp(sp->s_proto, "tcp") == 0) {
pai->ai_socktype = SOCK_STREAM;
pai->ai_protocol = IPPROTO_TCP;
} else
ERR(EAI_PROTOCOL); /*xxx*/
}
}
}
/*
* hostname == NULL.
* passive socket -> anyaddr (0.0.0.0 or ::)
* non-passive socket -> localhost (127.0.0.1 or ::1)
*/
if (hostname == NULL) {
struct gai_afd *gai_afd;
for (gai_afd = &gai_afdl[0]; gai_afd->a_af; gai_afd++) {
if (!(pai->ai_family == PF_UNSPEC
|| pai->ai_family == gai_afd->a_af)) {
continue;
}
if (pai->ai_flags & AI_PASSIVE) {
GET_AI(cur->ai_next, gai_afd, gai_afd->a_addrany, port);
/* xxx meaningless?
* GET_CANONNAME(cur->ai_next, "anyaddr");
*/
} else {
GET_AI(cur->ai_next, gai_afd, gai_afd->a_loopback,
port);
/* xxx meaningless?
* GET_CANONNAME(cur->ai_next, "localhost");
*/
}
cur = cur->ai_next;
}
top = sentinel.ai_next;
if (top)
goto good;
else
ERR(EAI_FAMILY);
}
/* hostname as numeric name */
for (i = 0; gai_afdl[i].a_af; i++) {
if (inet_pton(gai_afdl[i].a_af, hostname, pton)) {
u_long v4a;
#ifdef ENABLE_IPV6
u_char pfx;
#endif
switch (gai_afdl[i].a_af) {
case AF_INET:
v4a = ((struct in_addr *)pton)->s_addr;
v4a = ntohl(v4a);
if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
pai->ai_flags &= ~AI_CANONNAME;
v4a >>= IN_CLASSA_NSHIFT;
if (v4a == 0 || v4a == IN_LOOPBACKNET)
pai->ai_flags &= ~AI_CANONNAME;
break;
#ifdef ENABLE_IPV6
case AF_INET6:
pfx = ((struct in6_addr *)pton)->s6_addr[0];
if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
pai->ai_flags &= ~AI_CANONNAME;
break;
#endif
}
if (pai->ai_family == gai_afdl[i].a_af ||
pai->ai_family == PF_UNSPEC) {
if (! (pai->ai_flags & AI_CANONNAME)) {
GET_AI(top, &gai_afdl[i], pton, port);
goto good;
}
/*
* if AI_CANONNAME and if reverse lookup
* fail, return ai anyway to pacify
* calling application.
*
* XXX getaddrinfo() is a name->address
* translation function, and it looks strange
* that we do addr->name translation here.
*/
get_name(pton, &gai_afdl[i], &top, pton, pai, port);
goto good;
} else
ERR(EAI_FAMILY); /*xxx*/
}
}
if (pai->ai_flags & AI_NUMERICHOST)
ERR(EAI_NONAME);
/* hostname as alphabetical name */
error = get_addr(hostname, pai->ai_family, &top, pai, port);
if (error == 0) {
if (top) {
good:
*res = top;
return SUCCESS;
} else
error = EAI_FAIL;
}
free:
if (top)
freeaddrinfo(top);
bad:
*res = NULL;
return error;
}
static int
get_name(addr, gai_afd, res, numaddr, pai, port0)
const char *addr;
struct gai_afd *gai_afd;
struct addrinfo **res;
char *numaddr;
struct addrinfo *pai;
int port0;
{
u_short port = port0 & 0xffff;
struct hostent *hp;
struct addrinfo *cur;
int error = 0;
#ifdef ENABLE_IPV6
int h_error;
#endif
#ifdef ENABLE_IPV6
hp = getipnodebyaddr(addr, gai_afd->a_addrlen, gai_afd->a_af, &h_error);
#else
hp = gethostbyaddr(addr, gai_afd->a_addrlen, AF_INET);
#endif
if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
GET_AI(cur, gai_afd, hp->h_addr_list[0], port);
GET_CANONNAME(cur, hp->h_name);
} else
GET_AI(cur, gai_afd, numaddr, port);
#ifdef ENABLE_IPV6
if (hp)
freehostent(hp);
#endif
*res = cur;
return SUCCESS;
free:
if (cur)
freeaddrinfo(cur);
#ifdef ENABLE_IPV6
if (hp)
freehostent(hp);
#endif
/* bad: */
*res = NULL;
return error;
}
static int
get_addr(hostname, af, res, pai, port0)
const char *hostname;
int af;
struct addrinfo **res;
struct addrinfo *pai;
int port0;
{
u_short port = port0 & 0xffff;
struct addrinfo sentinel;
struct hostent *hp;
struct addrinfo *top, *cur;
struct gai_afd *gai_afd;
int i, error = 0, h_error;
char *ap;
top = NULL;
sentinel.ai_next = NULL;
cur = &sentinel;
#ifdef ENABLE_IPV6
if (af == AF_UNSPEC) {
hp = getipnodebyname(hostname, AF_INET6,
AI_ADDRCONFIG|AI_ALL|AI_V4MAPPED, &h_error);
} else
hp = getipnodebyname(hostname, af, AI_ADDRCONFIG, &h_error);
#else
hp = gethostbyname(hostname);
h_error = h_errno;
#endif
if (hp == NULL) {
switch (h_error) {
case HOST_NOT_FOUND:
case NO_DATA:
error = EAI_NODATA;
break;
case TRY_AGAIN:
error = EAI_AGAIN;
break;
case NO_RECOVERY:
default:
error = EAI_FAIL;
break;
}
goto free;
}
if ((hp->h_name == NULL) || (hp->h_name[0] == 0) ||
(hp->h_addr_list[0] == NULL)) {
error = EAI_FAIL;
goto free;
}
for (i = 0; (ap = hp->h_addr_list[i]) != NULL; i++) {
switch (af) {
#ifdef ENABLE_IPV6
case AF_INET6:
gai_afd = &gai_afdl[N_INET6];
break;
#endif
#ifndef ENABLE_IPV6
default: /* AF_UNSPEC */
#endif
case AF_INET:
gai_afd = &gai_afdl[N_INET];
break;
#ifdef ENABLE_IPV6
default: /* AF_UNSPEC */
if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
ap += sizeof(struct in6_addr) -
sizeof(struct in_addr);
gai_afd = &gai_afdl[N_INET];
} else
gai_afd = &gai_afdl[N_INET6];
break;
#endif
}
#ifdef FAITH
if (translate && gai_afd->a_af == AF_INET) {
struct in6_addr *in6;
GET_AI(cur->ai_next, &gai_afdl[N_INET6], ap, port);
in6 = &((struct sockaddr_in6 *)cur->ai_next->ai_addr)->sin6_addr;
memcpy(&in6->s6_addr32[0], &faith_prefix,
sizeof(struct in6_addr) - sizeof(struct in_addr));
memcpy(&in6->s6_addr32[3], ap, sizeof(struct in_addr));
} else
#endif /* FAITH */
GET_AI(cur->ai_next, gai_afd, ap, port);
if (cur == &sentinel) {
top = cur->ai_next;
GET_CANONNAME(top, hp->h_name);
}
cur = cur->ai_next;
}
#ifdef ENABLE_IPV6
freehostent(hp);
#endif
*res = top;
return SUCCESS;
free:
if (top)
freeaddrinfo(top);
#ifdef ENABLE_IPV6
if (hp)
freehostent(hp);
#endif
/* bad: */
*res = NULL;
return error;
}
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