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authorWenzel, Alexander <alexander.wenzel@qsc.de>2016-06-21 15:49:54 (GMT)
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2016-06-21 18:56:28 (GMT)
commit35adc1fa7fbecea572afaf829a33454da0f764b0 (patch)
treedcfdda8fbb42d41a03833260205f9c7b2fe473dc
parente3848e3dd64a8d6437531488fe341354bc02eaed (diff)
inet/getaddrinfo: fix AF_V4MAPPED behavior for non IPv6 host resolution
When trying to resolve a hostname by getaddrinfo() using some specific settings, it will always return -EAI_NONAME (Name or service not known). To reproduce this behavior, you need to request an IPv6 address with the additional AF_V4MAPPED flag set from an non IPv6 capable hostname. If you choose a IPv4/IPv6 capable hostname like google.com, everything works fine. This patch is more or less a port [1][2] from the glibc and their behavior for the AF_V4MAPPED flag. To test the bug you can use the following snippet. ---- 8< ---- int ret; struct addrinfo* result; struct addrinfo hints; memset(&hints, 0, sizeof(struct addrinfo)); hints.ai_family = AF_INET6; hints.ai_flags = AI_V4MAPPED; ret = getaddrinfo("test.com", NULL, &hints, &result); printf("getaddrinfo(): %i", ret); ---- 8< ---- [1] https://sourceware.org/git/?p=glibc.git;a=commit;f=sysdeps/posix/getaddrinfo.c;h=925c3c5c71596c02f7e58a0ffcdcaae44eb065c1 [2] https://sourceware.org/git/?p=glibc.git;a=commit;f=sysdeps/posix/getaddrinfo.c;h=28977c2c1acb789660ad47e0d88e42486059c916 Signed-off-by: Alexander Wenzel <alexander.wenzel@qsc.de>
-rw-r--r--libc/inet/getaddrinfo.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/libc/inet/getaddrinfo.c b/libc/inet/getaddrinfo.c
index 7ae32be..a9000ae 100644
--- a/libc/inet/getaddrinfo.c
+++ b/libc/inet/getaddrinfo.c
@@ -391,6 +391,9 @@ static uint8_t __gai_precedence = 0; /* =1 - IPv6, IPv4
memcpy((*pat)->addr, h->h_addr_list[i], sizeof(_type)); \
pat = &((*pat)->next); \
} \
+ if (_family == AF_INET6 && i > 0) { \
+ got_ipv6 = true; \
+ } \
} \
}
@@ -404,6 +407,7 @@ gaih_inet(const char *name, const struct gaih_service *service,
struct gaih_servtuple *st;
struct gaih_addrtuple *at;
int rc;
+ bool got_ipv6 = false;
int v4mapped = req->ai_family == PF_INET6 && (req->ai_flags & AI_V4MAPPED);
unsigned seen = 0;
if (req->ai_flags & AI_ADDRCONFIG) {
@@ -586,7 +590,7 @@ gaih_inet(const char *name, const struct gaih_service *service,
#endif
if (req->ai_family == AF_INET
|| (!v4mapped && req->ai_family == AF_UNSPEC)
- || (v4mapped && (no_inet6_data != 0 || (req->ai_flags & AI_ALL)))
+ || (v4mapped && (!got_ipv6 || (req->ai_flags & AI_ALL)))
) {
if (!(req->ai_flags & AI_ADDRCONFIG) || (seen & SEEN_IPV4))
gethosts(AF_INET, struct in_addr);
@@ -705,6 +709,14 @@ gaih_inet(const char *name, const struct gaih_service *service,
if (at2->family == AF_INET6 || v4mapped) {
family = AF_INET6;
socklen = sizeof(struct sockaddr_in6);
+
+ /* If we looked up IPv4 mapped address discard them here if
+ the caller isn't interested in all address and we have
+ found at least one IPv6 address. */
+ if (got_ipv6
+ && (req->ai_flags & (AI_V4MAPPED|AI_ALL)) == AI_V4MAPPED
+ && IN6_IS_ADDR_V4MAPPED (at2->addr))
+ goto ignore;
}
#endif
#if defined __UCLIBC_HAS_IPV4__ && defined __UCLIBC_HAS_IPV6__
@@ -781,7 +793,7 @@ gaih_inet(const char *name, const struct gaih_service *service,
(*pai)->ai_next = NULL;
pai = &((*pai)->ai_next);
}
-
+ignore:
at2 = at2->next;
}
}