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Assume that IPv4 and IPv6 is always available

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In 2024, it is reasonable to assume that IPv4 and IPv6 is always
available on a socket() level.  We still keep the option to enable or
disable each IP version individually, as the routing might be broken or
undesirable for one of the versions.
This commit is contained in:
Ondřej Surý
2024-08-20 11:53:07 +02:00
parent 5b273b5726
commit e85399b1c0
2 changed files with 4 additions and 95 deletions
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8
lib/isc/include/isc/net.h
View File

@@ -188,27 +188,23 @@ ISC_LANG_BEGINDECLS
isc_result_t
isc_net_probeipv4(void);
/*%<
* Check if the system's kernel supports IPv4.
* Check if the IPv4 has been disabled.
*
* Returns:
*
*\li #ISC_R_SUCCESS IPv4 is supported.
*\li #ISC_R_NOTFOUND IPv4 is not supported.
*\li #ISC_R_DISABLED IPv4 is disabled.
*\li #ISC_R_UNEXPECTED
*/
isc_result_t
isc_net_probeipv6(void);
/*%<
* Check if the system's kernel supports IPv6.
* Check if the IPv6 has been disabled.
*
* Returns:
*
*\li #ISC_R_SUCCESS IPv6 is supported.
*\li #ISC_R_NOTFOUND IPv6 is not supported.
*\li #ISC_R_DISABLED IPv6 is disabled.
*\li #ISC_R_UNEXPECTED
*/
isc_result_t

91
lib/isc/net.c
View File

@@ -101,100 +101,17 @@ static isc_once_t once_ipv6pktinfo = ISC_ONCE_INIT;
#endif /* ! __APPLE__ */
#endif /* ! ISC_CMSG_IP_TOS */
static isc_once_t once = ISC_ONCE_INIT;
static isc_result_t ipv4_result = ISC_R_NOTFOUND;
static isc_result_t ipv6_result = ISC_R_NOTFOUND;
static isc_result_t ipv4_result = ISC_R_SUCCESS;
static isc_result_t ipv6_result = ISC_R_SUCCESS;
static isc_result_t ipv6pktinfo_result = ISC_R_NOTFOUND;
static isc_result_t
try_proto(int domain) {
int s;
isc_result_t result = ISC_R_SUCCESS;
s = socket(domain, SOCK_STREAM, 0);
if (s == -1) {
switch (errno) {
#ifdef EAFNOSUPPORT
case EAFNOSUPPORT:
#endif /* ifdef EAFNOSUPPORT */
#ifdef EPFNOSUPPORT
case EPFNOSUPPORT:
#endif /* ifdef EPFNOSUPPORT */
#ifdef EPROTONOSUPPORT
case EPROTONOSUPPORT:
#endif /* ifdef EPROTONOSUPPORT */
#ifdef EINVAL
case EINVAL:
#endif /* ifdef EINVAL */
return ISC_R_NOTFOUND;
default:
UNEXPECTED_SYSERROR(errno, "socket()");
return ISC_R_UNEXPECTED;
}
}
if (domain == PF_INET6) {
struct sockaddr_in6 sin6;
unsigned int len;
/*
* Check to see if IPv6 is broken, as is common on Linux.
*/
len = sizeof(sin6);
if (getsockname(s, (struct sockaddr *)&sin6, (void *)&len) < 0)
{
isc_log_write(ISC_LOGCATEGORY_GENERAL,
ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
"retrieving the address of an IPv6 "
"socket from the kernel failed.");
isc_log_write(ISC_LOGCATEGORY_GENERAL,
ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
"IPv6 is not supported.");
result = ISC_R_NOTFOUND;
} else {
if (len == sizeof(struct sockaddr_in6)) {
result = ISC_R_SUCCESS;
} else {
isc_log_write(ISC_LOGCATEGORY_GENERAL,
ISC_LOGMODULE_SOCKET,
ISC_LOG_ERROR,
"IPv6 structures in kernel and "
"user space do not match.");
isc_log_write(ISC_LOGCATEGORY_GENERAL,
ISC_LOGMODULE_SOCKET,
ISC_LOG_ERROR,
"IPv6 is not supported.");
result = ISC_R_NOTFOUND;
}
}
}
(void)close(s);
return result;
}
static void
initialize_action(void) {
ipv4_result = try_proto(PF_INET);
ipv6_result = try_proto(PF_INET6);
}
static void
initialize(void) {
isc_once_do(&once, initialize_action);
}
isc_result_t
isc_net_probeipv4(void) {
initialize();
return ipv4_result;
}
isc_result_t
isc_net_probeipv6(void) {
initialize();
return ipv6_result;
}
@@ -382,7 +299,6 @@ isc_net_getudpportrange(int af, in_port_t *low, in_port_t *high) {
void
isc_net_disableipv4(void) {
initialize();
if (ipv4_result == ISC_R_SUCCESS) {
ipv4_result = ISC_R_DISABLED;
}
@@ -390,7 +306,6 @@ isc_net_disableipv4(void) {
void
isc_net_disableipv6(void) {
initialize();
if (ipv6_result == ISC_R_SUCCESS) {
ipv6_result = ISC_R_DISABLED;
}
@@ -398,7 +313,6 @@ isc_net_disableipv6(void) {
void
isc_net_enableipv4(void) {
initialize();
if (ipv4_result == ISC_R_DISABLED) {
ipv4_result = ISC_R_SUCCESS;
}
@@ -406,7 +320,6 @@ isc_net_enableipv4(void) {
void
isc_net_enableipv6(void) {
initialize();
if (ipv6_result == ISC_R_DISABLED) {
ipv6_result = ISC_R_SUCCESS;
}