Skip to content

Commit

Permalink
ext/socket: Use c-ares for name resolution (PoC)
Browse files Browse the repository at this point in the history 
This is an experimental patch to make `Addrinfo.getaddrinfo` use c-ares,
which is an asynchronous name resolver, as a backend.
This allows `Addrinfo.getaddrinfo` to be interrupted.
  • Loading branch information
@mame
mame committed Feb 10, 2023
1 parent b9f90ca commit 5478061
Show file tree
Hide file tree
Showing 5 changed files with 242 additions and 6 deletions.
4 changes: 4 additions & 0 deletions ext/socket/extconf.rb
View file
Expand Up @@ -443,6 +443,10 @@ def (fmt = "none").%(x)
have_struct_member('struct tcp_info', 'tcpi_snd_zerowin', headers)
end

if have_header("ares.h")
have_library("cares")
end

case RUBY_PLATFORM
when /mswin(32|64)|mingw/
test_func = "WSACleanup"
Expand Down
4 changes: 4 additions & 0 deletions ext/socket/init.c
View file
Expand Up @@ -755,6 +755,10 @@ rsock_getfamily(rb_io_t *fptr)
void
rsock_init_socket_init(void)
{
#if USE_ARES
ares_library_init(ARES_LIB_INIT_ALL);
#endif

/*
* SocketError is the error class for socket.
*/
Expand Down
227 changes: 224 additions & 3 deletions ext/socket/raddrinfo.c
View file
Expand Up @@ -174,6 +174,215 @@ parse_numeric_port(const char *service, int *portp)
#endif

#ifndef GETADDRINFO_EMU

#if USE_ARES

static int
convert_libc2ares_flags(int libc_flags)
{
int ares_flags = 0;
#define CONV(name) if (libc_flags & name) ares_flags |= ARES_##name;
CONV(AI_CANONNAME);
CONV(AI_NUMERICHOST);
CONV(AI_PASSIVE);
CONV(AI_NUMERICSERV);
CONV(AI_V4MAPPED);
CONV(AI_ALL);
CONV(AI_ADDRCONFIG);
//CONV(AI_NOSORT);
//CONV(AI_ENVHOSTS);
#undef CONV
return ares_flags;
}

static int
convert_ares2libc_flags(int ares_flags)
{
int libc_flags = 0;
#define CONV(name) if (ares_flags & ARES_##name) libc_flags |= name;
CONV(AI_CANONNAME);
CONV(AI_NUMERICHOST);
CONV(AI_PASSIVE);
CONV(AI_NUMERICSERV);
CONV(AI_V4MAPPED);
CONV(AI_ALL);
CONV(AI_ADDRCONFIG);
//CONV(AI_NOSORT);
//CONV(AI_ENVHOSTS);
#undef CONV
return libc_flags;
}

static struct addrinfo *
convert_ares2libc_addrinfo(struct ares_addrinfo *ares_ai)
{
struct addrinfo *libc_ai, **ptr = &libc_ai;
struct ares_addrinfo_node *node = ares_ai->nodes;

while (node) {
*ptr = NULL;
*ptr = (struct addrinfo *)xmalloc(sizeof(struct addrinfo));
(*ptr)->ai_flags = convert_ares2libc_flags(node->ai_flags);
(*ptr)->ai_family = node->ai_family;
(*ptr)->ai_socktype = node->ai_socktype;
(*ptr)->ai_protocol = node->ai_protocol;
(*ptr)->ai_addrlen = node->ai_addrlen;
(*ptr)->ai_canonname = NULL; // TODO
(*ptr)->ai_addr = NULL;
(*ptr)->ai_addr = (struct sockaddr *)xmalloc(sizeof(struct sockaddr));
memcpy((*ptr)->ai_addr, node->ai_addr, sizeof(struct sockaddr));
ptr = &(*ptr)->ai_next;
node = node->ai_next;
}
*ptr = NULL;

return libc_ai;
}

struct rb_ares_getaddrinfo_data {
const char *node;
const char *service;
const struct addrinfo *hints;
struct timeval *timeout;

ares_channel channel;
int done, fdset_allocated;
rb_fdset_t readers, writers;
int status;
struct ares_addrinfo *result;

struct rb_addrinfo *res;
};

static void
do_ares_getaddrinfo_callback(void *arg, int status, int timeouts, struct ares_addrinfo *result)
{
struct rb_ares_getaddrinfo_data *data = (struct rb_ares_getaddrinfo_data *)arg;

data->done = 1;
data->status = status;
data->result = result;
}

static VALUE
do_ares_getaddrinfo_core(VALUE arg)
{
struct rb_ares_getaddrinfo_data *data = (struct rb_ares_getaddrinfo_data *)arg;
struct ares_addrinfo_hints hints = {
.ai_flags = convert_libc2ares_flags(data->hints->ai_flags),
.ai_family = data->hints->ai_family,
.ai_socktype = data->hints->ai_socktype,
.ai_protocol = data->hints->ai_protocol
};

data->done = 0;

ares_getaddrinfo(data->channel, data->node, data->service, &hints, do_ares_getaddrinfo_callback, &data);

while (!data->done) {
int i, nfds;

fd_set readers, writers;
FD_ZERO(&readers);
FD_ZERO(&writers);
nfds = ares_fds(data->channel, &readers, &writers);
if (nfds == 0) return EAI_NONAME;

// Now assumes the second rb_fd_init should succeed if the first one succeeded
rb_fd_init(&data->readers);
rb_fd_init(&data->writers);
data->fdset_allocated = 1;

for (i = 0; i < nfds; i++) {
if (FD_ISSET(i, &readers)) rb_fd_set(i, &data->readers);
if (FD_ISSET(i, &writers)) rb_fd_set(i, &data->writers);
}

if (rb_thread_fd_select(nfds, &data->readers, &data->writers, NULL, data->timeout) == 0) {
// TODO: We need to check if the timeout is really exceeded.
// The select may return due to a signal interruption
return (VALUE)EAI_AGAIN;
}

rb_fd_term(&data->readers);
rb_fd_term(&data->writers);
data->fdset_allocated = 0;

ares_process(data->channel, &readers, &writers);
}

if (data->status == ARES_SUCCESS) {
data->res = (struct rb_addrinfo *)xmalloc(sizeof(struct rb_addrinfo));
data->res->allocated_by_malloc = 0;
data->res->ai = convert_ares2libc_addrinfo(data->result);
data->res->allocated_by_malloc = 1;
return (VALUE)0;
}
else {
switch (data->status) {
case ARES_ENOTIMP:
return (VALUE)EAI_FAMILY;
case ARES_ENOTFOUND:
return (VALUE)EAI_NONAME;
case ARES_ENOMEM:
return (VALUE)EAI_MEMORY;
case ARES_ECANCELLED:
case ARES_EDESTRUCTION:
return (VALUE)EAI_AGAIN; /* appropriate? */
default: // just for case
return EAI_NONAME;
}
}
}

static VALUE
do_ares_getaddrinfo_free(VALUE arg)
{
struct rb_ares_getaddrinfo_data *data = (struct rb_ares_getaddrinfo_data *)arg;

ares_destroy(data->channel);

if (data->result) ares_freeaddrinfo(data->result);

if (data->res && data->res->allocated_by_malloc == 0) {
struct addrinfo *ptr = data->res->ai, *ptr2;
while (ptr) {
if (ptr->ai_addr) xfree(ptr->ai_addr);
ptr2 = ptr->ai_next;
xfree(ptr);
ptr = ptr2;
}
}

if (data->fdset_allocated) {
rb_fd_term(&data->readers);
rb_fd_term(&data->writers);
}

return Qnil;
}

static int
do_ares_getaddrinfo(const char *hostp, const char *portp, const struct addrinfo *hints, struct rb_addrinfo **res, struct timeval *timeout)
{
struct rb_ares_getaddrinfo_data data = {
.node = hostp,
.service = portp,
.hints = hints,
.timeout = timeout
};

if (ares_init(&data.channel) != ARES_SUCCESS) return EAI_MEMORY;

int error = (int)rb_ensure(do_ares_getaddrinfo_core, (VALUE)&data, do_ares_getaddrinfo_free, (VALUE)&data);

*res = data.res;

return error;
}

#else // USE_ARES

struct getaddrinfo_arg
{
const char *node;
Expand All @@ -199,6 +408,8 @@ nogvl_getaddrinfo(void *arg)
}
#endif

#endif

static int
numeric_getaddrinfo(const char *node, const char *service,
const struct addrinfo *hints,
Expand Down Expand Up @@ -515,7 +726,7 @@ rb_scheduler_getaddrinfo(VALUE scheduler, VALUE host, const char *service,
}

struct rb_addrinfo*
rsock_getaddrinfo(VALUE host, VALUE port, struct addrinfo *hints, int socktype_hack)
rsock_getaddrinfo(VALUE host, VALUE port, struct addrinfo *hints, int socktype_hack, VALUE timeout)
{
struct rb_addrinfo* res = NULL;
struct addrinfo *ai;
Expand Down Expand Up @@ -550,6 +761,15 @@ rsock_getaddrinfo(VALUE host, VALUE port, struct addrinfo *hints, int socktype_h
}

if (!resolved) {
#if USE_ARES
struct timeval timeout_timeval, *timeoutp = NULL;
if (!NIL_P(timeout)) {
timeout_timeval = rb_time_interval(timeout);
timeoutp = &timeout_timeval;
}
error = do_ares_getaddrinfo(hostp, portp, hints, &res, timeoutp);
#else

#ifdef GETADDRINFO_EMU
error = getaddrinfo(hostp, portp, hints, &ai);
#else
Expand All @@ -566,6 +786,7 @@ rsock_getaddrinfo(VALUE host, VALUE port, struct addrinfo *hints, int socktype_h
res->allocated_by_malloc = 0;
res->ai = ai;
}
#endif
}
}

Expand Down Expand Up @@ -601,7 +822,7 @@ rsock_addrinfo(VALUE host, VALUE port, int family, int socktype, int flags)
hints.ai_family = family;
hints.ai_socktype = socktype;
hints.ai_flags = flags;
return rsock_getaddrinfo(host, port, &hints, 1);
return rsock_getaddrinfo(host, port, &hints, 1, Qnil);
}

VALUE
Expand Down Expand Up @@ -883,7 +1104,7 @@ call_getaddrinfo(VALUE node, VALUE service,
hints.ai_flags = NUM2INT(flags);
}

res = rsock_getaddrinfo(node, service, &hints, socktype_hack);
res = rsock_getaddrinfo(node, service, &hints, socktype_hack, timeout);

if (res == NULL)
rb_raise(rb_eSocket, "host not found");
Expand Down
9 changes: 8 additions & 1 deletion ext/socket/rubysocket.h
View file
Expand Up @@ -327,7 +327,7 @@ VALUE rsock_freeaddrinfo(VALUE arg);
int rb_getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, size_t hostlen, char *serv, size_t servlen, int flags);
int rsock_fd_family(int fd);
struct rb_addrinfo *rsock_addrinfo(VALUE host, VALUE port, int family, int socktype, int flags);
struct rb_addrinfo *rsock_getaddrinfo(VALUE host, VALUE port, struct addrinfo *hints, int socktype_hack);
struct rb_addrinfo *rsock_getaddrinfo(VALUE host, VALUE port, struct addrinfo *hints, int socktype_hack, VALUE timeout);

VALUE rsock_fd_socket_addrinfo(int fd, struct sockaddr *addr, socklen_t len);
VALUE rsock_io_socket_addrinfo(VALUE io, struct sockaddr *addr, socklen_t len);
Expand Down Expand Up @@ -467,4 +467,11 @@ const char *inet_ntop(int, const void *, char *, size_t);
const char *WSAAPI inet_ntop(int, const void *, char *, size_t);
#endif

#ifdef HAVE_ARES_H
# include <ares.h>
# define USE_ARES 1
#else
# define USE_ARES 0
#endif

#endif
4 changes: 2 additions & 2 deletions ext/socket/socket.c
View file
Expand Up @@ -1183,7 +1183,7 @@ sock_s_getaddrinfo(int argc, VALUE *argv, VALUE _)
norevlookup = rsock_do_not_reverse_lookup;
}

res = rsock_getaddrinfo(host, port, &hints, 0);
res = rsock_getaddrinfo(host, port, &hints, 0, Qnil);

ret = make_addrinfo(res, norevlookup);
rb_freeaddrinfo(res);
Expand Down Expand Up @@ -1279,7 +1279,7 @@ sock_s_getnameinfo(int argc, VALUE *argv, VALUE _)
hints.ai_socktype = (fl & NI_DGRAM) ? SOCK_DGRAM : SOCK_STREAM;
/* af */
hints.ai_family = NIL_P(af) ? PF_UNSPEC : rsock_family_arg(af);
res = rsock_getaddrinfo(host, port, &hints, 0);
res = rsock_getaddrinfo(host, port, &hints, 0, Qnil);
sap = res->ai->ai_addr;
salen = res->ai->ai_addrlen;
}
Expand Down

0 comments on commit 5478061

Please sign in to comment.