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sockets: factor out a new try_bind() function 

A refactoring step to prepare for the problem
exposed by the test-listen test in the previous commit.

Simplify and reorganize the IPv6 specific extra
measures and move it out of the for loop to increase
code readability. No semantic changes.

Signed-off-by: Knut Omang <knut.omang@oracle.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This commit is contained in:
Knut Omang 2017-08-07 12:58:40 +02:00 committed by Daniel P. Berrange
parent 79b2a13aa8
commit 89382c3de5
1 changed files with 39 additions and 30 deletions
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69
util/qemu-sockets.c
View File

@ -149,6 +149,44 @@ int inet_ai_family_from_address(InetSocketAddress *addr,
return PF_UNSPEC;
}
static int try_bind(int socket, InetSocketAddress *saddr, struct addrinfo *e)
{
#ifndef IPV6_V6ONLY
return bind(socket, e->ai_addr, e->ai_addrlen);
#else
/*
* Deals with first & last cases in matrix in comment
* for inet_ai_family_from_address().
*/
int v6only =
((!saddr->has_ipv4 && !saddr->has_ipv6) ||
(saddr->has_ipv4 && saddr->ipv4 &&
saddr->has_ipv6 && saddr->ipv6)) ? 0 : 1;
int stat;
rebind:
if (e->ai_family == PF_INET6) {
qemu_setsockopt(socket, IPPROTO_IPV6, IPV6_V6ONLY, &v6only,
sizeof(v6only));
}
stat = bind(socket, e->ai_addr, e->ai_addrlen);
if (!stat) {
return 0;
}
/* If we got EADDRINUSE from an IPv6 bind & v6only is unset,
* it could be that the IPv4 port is already claimed, so retry
* with v6only set
*/
if (e->ai_family == PF_INET6 && errno == EADDRINUSE && !v6only) {
v6only = 1;
goto rebind;
}
return stat;
#endif
}
static int inet_listen_saddr(InetSocketAddress *saddr,
int port_offset,
bool update_addr,
@ -228,39 +266,10 @@ static int inet_listen_saddr(InetSocketAddress *saddr,
port_min = inet_getport(e);
port_max = saddr->has_to ? saddr->to + port_offset : port_min;
for (p = port_min; p <= port_max; p++) {
#ifdef IPV6_V6ONLY
/*
* Deals with first & last cases in matrix in comment
* for inet_ai_family_from_address().
*/
int v6only =
((!saddr->has_ipv4 && !saddr->has_ipv6) ||
(saddr->has_ipv4 && saddr->ipv4 &&
saddr->has_ipv6 && saddr->ipv6)) ? 0 : 1;
#endif
inet_setport(e, p);
#ifdef IPV6_V6ONLY
rebind:
if (e->ai_family == PF_INET6) {
qemu_setsockopt(slisten, IPPROTO_IPV6, IPV6_V6ONLY, &v6only,
sizeof(v6only));
}
#endif
if (bind(slisten, e->ai_addr, e->ai_addrlen) == 0) {
if (try_bind(slisten, saddr, e) >= 0) {
goto listen;
}
#ifdef IPV6_V6ONLY
/* If we got EADDRINUSE from an IPv6 bind & V6ONLY is unset,
* it could be that the IPv4 port is already claimed, so retry
* with V6ONLY set
*/
if (e->ai_family == PF_INET6 && errno == EADDRINUSE && !v6only) {
v6only = 1;
goto rebind;
}
#endif
if (p == port_max) {
if (!e->ai_next) {
error_setg_errno(errp, errno, "Failed to bind socket");