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SockAddr fallback to sync. dns lookup

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This commit is contained in:
Michael Davidsaver
2022-04-06 00:04:14 -07:00
parent 0ad81d0f49
commit bebd7a91aa
2 changed files with 80 additions and 6 deletions
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src/util.cpp
+38 -5
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@@ -275,13 +275,16 @@ SockAddr::SockAddr(const char *address, unsigned short port)
setAddress(address, port);
}
SockAddr::SockAddr(const sockaddr *addr)
SockAddr::SockAddr(const sockaddr *addr, socklen_t alen)
:SockAddr(addr ? addr->sa_family : AF_UNSPEC)
{
if(!addr)
return; // treat NULL as AF_UNSPEC
if(family()!=AF_UNSPEC && family()!=AF_INET && family()!=AF_INET6)
if(family()==AF_UNSPEC) {}
else if(family()==AF_INET && (!alen || alen>=sizeof(sockaddr_in))) {}
else if(family()==AF_INET6 && (!alen || alen>=sizeof(sockaddr_in6))) {}
else
throw std::invalid_argument("Unsupported address family");
if(family()!=AF_UNSPEC)
@@ -402,8 +405,26 @@ void SockAddr::setAddress(const char *name, unsigned short defport)
throw std::runtime_error(SB()<<"Invalid IP address form \""<<escape(name)<<"\"");
}
if(evutil_inet_pton(temp->sa.sa_family, addr, sockaddr)<=0)
throw std::runtime_error(SB()<<"Not a valid IP address \""<<escape(name)<<"\"");
if(evutil_inet_pton(temp->sa.sa_family, addr, sockaddr)<=0) {
// not a plain IP4/6 address.
// Fall back to synchronous DNS lookup (could be sloooow)
GetAddrInfo info(addr);
// We may get a mixture of IP v4 and/or v6 addresses.
// For maximum compatibility, we always prefer IPv4
for(const auto addr : info) {
if(addr.family()==AF_INET || (addr.family()==AF_INET6 && temp.family()==AF_UNSPEC)) {
temp = addr;
if(addr.family()==AF_INET)
break;
}
}
if(temp.family()==AF_UNSPEC) // lookup succeeded, but no addresses. Can this happen?
throw std::runtime_error(SB()<<"Not a valid host name or IP address \""<<escape(name)<<"\"");
}
if(port)
temp.setPort(parseTo<uint64_t>(port));
@@ -555,10 +576,22 @@ std::ostream& operator<<(std::ostream& strm, const SockAddr& addr)
return strm;
}
GetAddrInfo::GetAddrInfo(const char *name)
{
if(auto err = evutil_getaddrinfo(name, nullptr, nullptr, &info)) {
throw std::runtime_error(SB()<<"Error resolving \""<<escape(name)<<"\" : "<<evutil_gai_strerror(err));
}
}
GetAddrInfo::~GetAddrInfo()
{
if(info)
evutil_freeaddrinfo(info);
}
} // namespace pvxs
namespace pvxs {namespace impl {
struct onceArgs {
EPICSTHREADFUNC fn;
void *arg;