Re: [libvirt] [PATCH 2/2] util: introduce virSocketAddrParseAny

On 03/29/2018 11:27 AM, John Ferlan wrote: > > > On 03/26/2018 04:29 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 virSocketAddrParseAny and use it when simply testing if a host >> name/addr is parsable. >> >> Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; >> --- >> >> Essentially a V2 of >> >> https://www.redhat.com/archives/libvir-list/2018-March/msg01120.html >> >> It takes a slightly different approach by creating a function that can >> parse host names or IP addresses. >> >>   src/libvirt_private.syms |  1 + >>   src/rpc/virnetsocket.c   |  2 +- >>   src/util/virsocketaddr.c | 50 +++++++++++++++++++++++++++++++++++++++++++++--- >>   src/util/virsocketaddr.h |  5 +++++ >>   4 files changed, 54 insertions(+), 4 deletions(-) >> > > Reviewed-by: John Ferlan <jferlan(a)redhat.com&gt; > > Wait for 4.2.0 for this one... > > John > > BTW: Your call on whether to add to the new API comments something about > the API could be susceptible to a delay due to network name resolution > lookup pause.  That is, from the getaddrinfo man page: > > "The AI_NUMERICHOST flag suppresses any potentially lengthy network host > address lookups." Good point. I squashed in the below comment to this patch before pushing both. Regards, Jim diff --git a/src/util/virsocketaddr.c b/src/util/virsocketaddr.c index 84610560f..99dc54830 100644 --- a/src/util/virsocketaddr.c +++ b/src/util/virsocketaddr.c @@ -173,7 +173,10 @@ int virSocketAddrParse(virSocketAddrPtr addr, const char *val, int family)   *   * Mostly a wrapper for getaddrinfo() extracting the address storage   * from a host name like acme.example.com or a numeric string like 1.2.3.4 - * or 2001:db8:85a3:0:0:8a2e:370:7334 + * or 2001:db8:85a3:0:0:8a2e:370:7334. + * + * When @val is a network host name, this function may be susceptible to a + * delay due to potentially lengthy netork host address lookups.