On 03/19/2018 07:28 PM, Jim Fehlig wrote:
When preparing for migration, the libxl driver creates a new TCP
listen
socket for the incoming migration by calling virNetSocketNewListenTCP,
passing the destination host name. virNetSocketNewListenTCP calls
virSocketAddrParse to check if the host name is a wildcard address, in
which case it avoids adding the AI_ADDRCONFIG flag to the hints passed to
getaddrinfo. If the host name is not an IP address, virSocketAddrParse
reports an error
error : virSocketAddrParseInternal:121 : Cannot parse socket address
'myhost.example.com': Name or service not known
But virNetSocketNewListenTCP succeeds regardless and the overall migration
operation succeeds.
Introduce virSocketAddrParseQuiet and use it when simply testing if a host
name/addr is parsable.
Signed-off-by: Jim Fehlig <jfehlig(a)suse.com>
---
A brute-force hack that also works is to remove AI_NUMERICHOST flag from
hints in virSocketAddrParseInternal, but I'm not sure what sort of havoc
that would wreak
Perhaps rather than quiet/verbose flag - maybe ParseInternal should add
a new parameter "ai_flags"? Then add virSocketAddrParseName which would
pass 0 instead of AI_NUMERICHOST and expect to parse the name. FWIW, I
have a faint recollection of some issue with getaddrinfo and dns delays
on lookups when looking up by name. Been a while since I've had to think
about that though, so I could be wrong as the memory fades/ages.
You could also search on some other direct callers of getaddrinfo in
libvirt sources - there's some interesting uses..
I also note (ironically) that if @addr == NULL, then error is splatted
in ParseInternal regardless of @reportError value.
Perhaps I should ask the obvious question first: Is virSocketAddrParse
expected to work with a host name? I suspec there are other callers that
could pass a name as well as a numeric IP addr, depending on URI provided
by user.
Seems to me some comments [1] answer your question.
There's a virSocketAddrNumericFamily - maybe that'll help you in
deciding how to formulate things... Seems to be used by a few places
already to determine whether one has a name or number (including the
qemu migration path).
FWIW: I also note callers to virSocketAddrNumericFamily don't
necessarily handle the possible -1 return possibly... Looks like you're
jumping into one of rabbit holes Laine usually falls into ;-)
src/libvirt_private.syms | 1 +
src/rpc/virnetsocket.c | 2 +-
src/util/virsocketaddr.c | 60 +++++++++++++++++++++++++++++++++++-------------
src/util/virsocketaddr.h | 4 ++++
4 files changed, 50 insertions(+), 17 deletions(-)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index c3e4fd23d..acacbaeb1 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2726,6 +2726,7 @@ virSocketAddrNumericFamily;
virSocketAddrParse;
virSocketAddrParseIPv4;
virSocketAddrParseIPv6;
+virSocketAddrParseQuiet;
virSocketAddrPrefixToNetmask;
virSocketAddrPTRDomain;
virSocketAddrSetIPv4Addr;
diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
index 2d41a716b..07166ecc9 100644
--- a/src/rpc/virnetsocket.c
+++ b/src/rpc/virnetsocket.c
@@ -333,7 +333,7 @@ int virNetSocketNewListenTCP(const char *nodename,
* startup in most cases.
*/
if (nodename &&
- !(virSocketAddrParse(&tmp_addr, nodename, AF_UNSPEC) > 0 &&
+ !(virSocketAddrParseQuiet(&tmp_addr, nodename, AF_UNSPEC) > 0 &&
virSocketAddrIsWildcard(&tmp_addr)))
hints.ai_flags |= AI_ADDRCONFIG;
diff --git a/src/util/virsocketaddr.c b/src/util/virsocketaddr.c
index 95b527436..711c634e8 100644
--- a/src/util/virsocketaddr.c
+++ b/src/util/virsocketaddr.c
@@ -126,29 +126,24 @@ virSocketAddrParseInternal(struct addrinfo **res,
return 0;
}
-/**
- * virSocketAddrParse:
- * @val: a numeric network address IPv4 or IPv6
- * @addr: where to store the return value, optional.
- * @family: address family to pass down to getaddrinfo
- *
- * Mostly a wrapper for getaddrinfo() extracting the address storage
- * from the numeric string like 1.2.3.4 or 2001:db8:85a3:0:0:8a2e:370:7334
- *
[1]
- * Returns the length of the network address or -1 in case of
error.
- */
-int virSocketAddrParse(virSocketAddrPtr addr, const char *val, int family)
+static int
+virSockAddrParseVerbose(virSocketAddrPtr addr,
+ const char *val,
+ int family,
+ bool verbose)
Could have gone with reportError like ParseInternal.
John
{
int len;
struct addrinfo *res;
- if (virSocketAddrParseInternal(&res, val, family, true) < 0)
+ if (virSocketAddrParseInternal(&res, val, family, verbose) < 0)
return -1;
if (res == NULL) {
- virReportError(VIR_ERR_SYSTEM_ERROR,
- _("No socket addresses found for '%s'"),
- val);
+ if (verbose) {
+ virReportError(VIR_ERR_SYSTEM_ERROR,
+ _("No socket addresses found for '%s'"),
+ val);
+ }
return -1;
}
@@ -162,6 +157,39 @@ int virSocketAddrParse(virSocketAddrPtr addr, const char *val, int
family)
return len;
}
+
+/**
+ * virSocketAddrParse:
+ * @val: a numeric network address IPv4 or IPv6
+ * @addr: where to store the return value, optional.
+ * @family: address family to pass down to getaddrinfo
+ *
+ * Mostly a wrapper for getaddrinfo() extracting the address storage
+ * from the numeric string like 1.2.3.4 or 2001:db8:85a3:0:0:8a2e:370:7334
+ *
+ * Returns the length of the network address or -1 in case of error.
+ */
+int virSocketAddrParse(virSocketAddrPtr addr, const char *val, int family)
+{
+ return virSockAddrParseVerbose(addr, val, family, true);
+}
+
+/**
+ * virSocketAddrParseQuiet:
+ * @val: a numeric network address IPv4 or IPv6
+ * @addr: where to store the return value, optional.
+ * @family: address family to pass down to getaddrinfo
+ *
+ * A quiet version of virSocketAddrParse. No errors are reported in
+ * error paths.
+ *
+ * Returns the length of the network address or -1 in case of error.
+ */
+int virSocketAddrParseQuiet(virSocketAddrPtr addr, const char *val, int family)
+{
+ return virSockAddrParseVerbose(addr, val, family, false);
+}
+
/*
* virSocketAddrParseIPv4:
* @val: an IPv4 numeric address
diff --git a/src/util/virsocketaddr.h b/src/util/virsocketaddr.h
index 80e792618..99bb7a949 100644
--- a/src/util/virsocketaddr.h
+++ b/src/util/virsocketaddr.h
@@ -92,6 +92,10 @@ int virSocketAddrParse(virSocketAddrPtr addr,
const char *val,
int family);
+int virSocketAddrParseQuiet(virSocketAddrPtr addr,
+ const char *val,
+ int family);
+
int virSocketAddrParseIPv4(virSocketAddrPtr addr,
const char *val);