getaddrinfo.c

Linux 2.6 内核上配置IPSec VPN 的工具

					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 afd *afd;
		int s;

		for (afd = &afdl[0]; afd->a_af; afd++) {
			if (!(pai->ai_family == PF_UNSPEC
			   || pai->ai_family == afd->a_af)) {
				continue;
			}

			/*
			 * filter out AFs that are not supported by the kernel
			 * XXX errno?
			 */
			s = socket(afd->a_af, SOCK_DGRAM, 0);
			if (s < 0)
				continue;
			close(s);

			if (pai->ai_flags & AI_PASSIVE) {
				GET_AI(cur->ai_next, afd, afd->a_addrany, port);
				/* xxx meaningless?
				 * GET_CANONNAME(cur->ai_next, "anyaddr");
				 */
			} else {
				GET_AI(cur->ai_next, afd, 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; afdl[i].a_af; i++) {
		if (inet_pton(afdl[i].a_af, hostname, pton) == 1) {
			u_long v4a;
			u_char pfx;

			switch (afdl[i].a_af) {
			case AF_INET:
				v4a = ntohl(((struct in_addr *)pton)->s_addr);
				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 INET6
			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 == afdl[i].a_af ||
			    pai->ai_family == PF_UNSPEC) {
				if (! (pai->ai_flags & AI_CANONNAME)) {
					GET_AI(top, &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, &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, afd, res, numaddr, pai, port0)
	const char *addr;
	struct afd *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 USE_GETIPNODEBY
	int h_error;

	hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
#else
	hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
#endif
	if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
		GET_AI(cur, afd, hp->h_addr_list[0], port);
		GET_CANONNAME(cur, hp->h_name);
	} else
		GET_AI(cur, afd, numaddr, port);
	
#ifdef USE_GETIPNODEBY
	if (hp)
		freehostent(hp);
#endif
	*res = cur;
	return SUCCESS;
 free:
	if (cur)
		freeaddrinfo(cur);
#ifdef USE_GETIPNODEBY
	if (hp)
		freehostent(hp);
#endif
 /* bad: */
	*res = NULL;
	return error;
}

static int
get_addr(hostname, af, res0, pai, port0)
	const char *hostname;
	int af;
	struct addrinfo **res0;
	struct addrinfo *pai;
	int port0;
{
#ifdef USE_GETIPNODEBY
	return get_addr0(hostname, af, res0, pai, port0);
#else
	int i, error, ekeep;
	struct addrinfo *cur;
	struct addrinfo **res;
	int retry;
	int s;

	res = res0;
	ekeep = 0;
	error = 0;
	for (i = 0; afdl[i].a_af; i++) {
		retry = 0;
		if (af == AF_UNSPEC) {
			/*
			 * filter out AFs that are not supported by the kernel
			 * XXX errno?
			 */
			s = socket(afdl[i].a_af, SOCK_DGRAM, 0);
			if (s < 0)
				continue;
			close(s);
		} else {
			if (af != afdl[i].a_af)
				continue;
		}
		/* It is WRONG, we need getipnodebyname(). */
again:
		error = get_addr0(hostname, afdl[i].a_af, res, pai, port0);
		switch (error) {
		case EAI_AGAIN:
			if (++retry < 3)
				goto again;
			/* FALL THROUGH*/
		default:
			if (ekeep == 0)
				ekeep = error;
			break;
		}
		if (*res) {
			/* make chain of addrs */
			for (cur = *res;
			     cur && cur->ai_next;
			     cur = cur->ai_next)
				;
			if (!cur)
				return EAI_FAIL;
			res = &cur->ai_next;
		}
	}

	/* if we got something, it's okay */
	if (*res0)
		return 0;

	return error ? error : ekeep;
#endif
}

static int
get_addr0(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 afd *afd;
	int i, error = 0, h_error;
	char *ap;
#ifndef USE_GETIPNODEBY
	extern int h_errno;
#endif

	top = NULL;
	sentinel.ai_next = NULL;
	cur = &sentinel;
#ifdef USE_GETIPNODEBY
	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
	if (af == AF_UNSPEC) {
		error = EAI_FAIL;
		goto bad;
	}
	hp = gethostbyname2(hostname, af);
	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:
		case NETDB_INTERNAL:
		default:
			error = EAI_FAIL;
			break;
		}
		goto bad;
	}

	if ((hp->h_name == NULL) || (hp->h_name[0] == 0) ||
	    (hp->h_addr_list[0] == NULL))
		ERR(EAI_FAIL);
	
	for (i = 0; (ap = hp->h_addr_list[i]) != NULL; i++) {
		switch (af) {
#ifdef INET6
		case AF_INET6:
			afd = &afdl[N_INET6];
			break;
#endif
#ifndef INET6
		default:	/* AF_UNSPEC */
#endif
		case AF_INET:
			afd = &afdl[N_INET];
			break;
#ifdef INET6
		default:	/* AF_UNSPEC */
			if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
				ap += sizeof(struct in6_addr) -
					sizeof(struct in_addr);
				afd = &afdl[N_INET];
			} else
				afd = &afdl[N_INET6];
			break;
#endif
		}
#ifdef FAITH
		if (translate && afd->a_af == AF_INET) {
			struct in6_addr *in6;

			GET_AI(cur->ai_next, &afdl[N_INET6], ap, port);
			in6 = &((struct sockaddr_in6 *)cur->ai_next->ai_addr)->sin6_addr;
			memcpy(&in6->s6_addr[0], &faith_prefix,
			    sizeof(struct in6_addr) - sizeof(struct in_addr));
			memcpy(&in6->s6_addr[12], ap, sizeof(struct in_addr));
		} else
#endif /* FAITH */
		GET_AI(cur->ai_next, afd, ap, port);
		if (cur == &sentinel) {
			top = cur->ai_next;
			GET_CANONNAME(top, hp->h_name);
		}
		cur = cur->ai_next;
	}
#ifdef USE_GETIPNODEBY
	freehostent(hp);
#endif
	*res = top;
	return SUCCESS;
 free:
	if (top)
		freeaddrinfo(top);
#ifdef USE_GETIPNODEBY
	if (hp)
		freehostent(hp);
#endif
 bad:
	*res = NULL;
	return error;
}