outstanding queries, and processing a DNS response packet was O(n) in the
number of outstanding queries. To speed things up in Google, we added a few circular,
doubly-linked lists of queries that are hash-bucketed based on
the attributes we care about, so most important operations are now O(1).
It might be that the number of buckets are higher than most people would need,
but on a quick calculation it should only be 100kB or so even on a 64-bit
system, so I've let it stay as-is.
several functions (write_tcp_data, read_tcp_data, read_udp_packets) so that
if it fails and the socket is closed the following code doesn't try to use
the file descriptor.
specific sockets and thus avoiding select() and associated functions/macros.
This function will be used by upcoming libcurl releases for this very
reason. It also made me export the ares_socket_t type in the public ares.h
header file, since ares_process_fd() uses that type for two of the arguments.
Check for lowercase 'bool' type at configuration stage. If not available
provide a suitable replacement with a type definition of 'unsigned char'
in setup_once.h
Move definitions of TRUE and FALSE to setup_once.h
Make UDP sockets non-blocking. I've confirmed that at least on Linux 2.4 a
read event can come back from poll() on a valid SOCK_DGRAM socket but
recv(2) will still block. This patch doesn't ignore EAGAIN in
read_udp_packets(), though maybe it should. (This patch was edited by Daniel
Stenberg and a new configure test was added (imported from curl's configure)
to properly detect what non-blocking socket approach to use.)
Basically in loops like handle_errors(), 'query->next' was assigned a local
variable and then query was referenced after the memory was freed by
next_server(). I've changed that so next_server() and end_query() returns the
next query. So callers should use this ret-value.
The next problem was that 'server->tcp_buffer_pos' had a random value at entry
to 1st recv() (luckily causing Winsock to return ENOBUFS).
I've also added a ares_writev() for Windows to streamline the code
a bit more.