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am 5d45fa40: am 2081fda6: Merge "Only look up A records if the system has IPv4." into gingerbread

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* commit '5d45fa4049d9ba03c0d922ece18d1d2dda119dc7':
  Only look up A records if the system has IPv4.
This commit is contained in:
David Turner 2011-01-21 15:50:23 -08:00 committed by Android Git Automerger
commit f03e2d3f31
1 changed files with 59 additions and 29 deletions
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88
libc/netbsd/net/getaddrinfo.c
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@ -347,35 +347,55 @@ str2number(const char *p)
return -1;
}
/* Determine whether IPv6 connectivity is available. */
/*
* Connect a UDP socket to a given unicast address. This will cause no network
* traffic, but will fail fast if the system has no or limited reachability to
* the destination (e.g., no IPv4 address, no IPv6 default route, ...).
*/
static int
_have_ipv6() {
/*
* Connect a UDP socket to an global unicast IPv6 address. This will
* cause no network traffic, but will fail fast if the system has no or
* limited IPv6 connectivity (e.g., only a link-local address).
*/
static const struct sockaddr_in6 sin6_test = {
/* family, port, flow label */
AF_INET6, 0, 0,
/* 2000:: */
{{{ 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }}},
/* scope ID */
0};
sockaddr_union addr_test;
addr_test.in6 = sin6_test;
int s = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
_test_connect(int pf, struct sockaddr *addr, size_t addrlen) {
int s = socket(pf, SOCK_DGRAM, IPPROTO_UDP);
if (s < 0)
return 0;
int ret;
do {
ret = connect(s, &addr_test.generic, sizeof(addr_test.in6));
ret = connect(s, addr, addrlen);
} while (ret < 0 && errno == EINTR);
int have_ipv6 = (ret == 0);
int success = (ret == 0);
do {
ret = close(s);
} while (ret < 0 && errno == EINTR);
return have_ipv6;
return success;
}
/*
* The following functions determine whether IPv4 or IPv6 connectivity is
* available in order to implement AI_ADDRCONFIG.
*
* Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is
* available, but whether addresses of the specified family are "configured
* on the local system". However, bionic doesn't currently support getifaddrs,
* so checking for connectivity is the next best thing.
*/
static int
_have_ipv6() {
static const struct sockaddr_in6 sin6_test = {
.sin6_family = AF_INET6,
.sin6_addr.s6_addr = { // 2000::
0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
};
sockaddr_union addr = { .in6 = sin6_test };
return _test_connect(PF_INET6, &addr.generic, sizeof(addr.in6));
}
static int
_have_ipv4() {
static const struct sockaddr_in sin_test = {
.sin_family = AF_INET,
.sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
};
sockaddr_union addr = { .in = sin_test };
return _test_connect(PF_INET, &addr.generic, sizeof(addr.in));
}
// Returns 0 on success, else returns non-zero on error (in which case
@ -1885,17 +1905,27 @@ _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
q.qclass = C_IN;
q.answer = buf->buf;
q.anslen = sizeof(buf->buf);
/* If AI_ADDRCONFIG, lookup IPv6 only if we have connectivity */
if (!(pai->ai_flags & AI_ADDRCONFIG) || _have_ipv6()) {
int query_ipv6 = 1, query_ipv4 = 1;
if (pai->ai_flags & AI_ADDRCONFIG) {
query_ipv6 = _have_ipv6();
query_ipv4 = _have_ipv4();
}
if (query_ipv6) {
q.qtype = T_AAAA;
q.next = &q2;
q2.name = name;
q2.qclass = C_IN;
q2.qtype = T_A;
q2.answer = buf2->buf;
q2.anslen = sizeof(buf2->buf);
} else {
if (query_ipv4) {
q.next = &q2;
q2.name = name;
q2.qclass = C_IN;
q2.qtype = T_A;
q2.answer = buf2->buf;
q2.anslen = sizeof(buf2->buf);
}
} else if (query_ipv4) {
q.qtype = T_A;
} else {
free(buf);
free(buf2);
return NS_NOTFOUND;
}
break;
case AF_INET: