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@xxxxxxxx>
> ---
>
> 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);
>
>
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