make DNS lookup asynchronous
true asynchronicity is actually fairly useless, as it's unlikely that both Stores in a Channel use IMAP, and both host resolutions take particularly long - the main objective is imposing the Timeout setting. however, we can't just use setjmp()+alarm(), as longjmp()ing out of getaddrinfo() is undefined, as it may for example free() just at the wrong time. so we go for the real thing. this implementation just fork()s out a process which uses getaddrinfo() (or gethostbyname()) per lookup. this isn't particularly scalable, but as we don't expect a lot of lookups, it seems adequate.
This commit is contained in:
Oswald Buddenhagen
parent
ced20ad0d9
commit
ec50c55c36
269
src/socket.c
269
src/socket.c
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@ -28,6 +28,7 @@
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#endif
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enum {
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SCK_RESOLVING,
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SCK_CONNECTING,
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#ifdef HAVE_LIBSSL
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SCK_STARTTLS,
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@ -415,6 +416,7 @@ static void socket_fd_cb( int, void * );
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static void socket_fake_cb( void * );
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static void socket_timeout_cb( void * );
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static void socket_resolve( conn_t * );
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static void socket_connect_one( conn_t * );
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static void socket_connect_next( conn_t * );
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static void socket_connect_failed( conn_t * );
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@ -422,15 +424,21 @@ static void socket_connected( conn_t * );
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static void socket_connect_bail( conn_t * );
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static void
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socket_open_internal( conn_t *sock, int fd )
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socket_register_internal( conn_t *sock, int fd )
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{
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sock->fd = fd;
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fcntl( fd, F_SETFL, O_NONBLOCK );
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init_notifier( &sock->notify, fd, socket_fd_cb, sock );
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init_wakeup( &sock->fd_fake, socket_fake_cb, sock );
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init_wakeup( &sock->fd_timeout, socket_timeout_cb, sock );
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}
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static void
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socket_open_internal( conn_t *sock, int fd )
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{
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fcntl( fd, F_SETFL, O_NONBLOCK );
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socket_register_internal( sock, fd );
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}
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static void
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socket_close_internal( conn_t *sock )
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{
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@ -441,32 +449,6 @@ socket_close_internal( conn_t *sock )
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sock->fd = -1;
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}
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#ifndef HAVE_IPV6
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struct addr_info {
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struct addr_info *ai_next;
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struct sockaddr_in ai_addr[1];
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};
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#define freeaddrinfo(ai) free( ai )
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static struct addr_info *
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init_addrinfo( struct hostent *he )
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{
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uint naddr = 0;
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for (char **addr = he->h_addr_list; *addr; addr++)
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naddr++;
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struct addr_info *caddr = nfzalloc( naddr * sizeof(struct addrinfo) );
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struct addr_info *ret, **caddrp = &ret;
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for (char **addr = he->h_addr_list; *addr; addr++, caddr++) {
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caddr->ai_addr->sin_family = AF_INET;
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memcpy( &caddr->ai_addr->sin_addr.s_addr, *addr, sizeof(struct in_addr) );
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*caddrp = caddr;
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caddrp = &caddr->ai_next;
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}
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return ret;
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}
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#endif
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void
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socket_connect( conn_t *sock, void (*cb)( int ok, void *aux ) )
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{
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@ -501,77 +483,202 @@ socket_connect( conn_t *sock, void (*cb)( int ok, void *aux ) )
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info( "\vok\n" );
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socket_connected( sock );
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} else {
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#ifdef HAVE_IPV6
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int gaierr;
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struct addrinfo hints;
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socket_resolve( sock );
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}
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}
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memset( &hints, 0, sizeof(hints) );
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static void
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pipe_write( int fd, void *buf, int len )
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{
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do {
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int wrote = write( fd, buf, len );
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if (wrote < 0) {
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perror( "write" );
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_exit( 1 );
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}
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buf = ((char *)buf) + wrote;
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len -= wrote;
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} while (len);
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}
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static void
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socket_resolve( conn_t *sock )
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{
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info( "Resolving %s...\n", sock->conf->host );
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int pfd[2];
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if (pipe( pfd )) {
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perror( "pipe" );
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exit( 1 );
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}
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switch (fork()) {
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case -1:
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perror( "fork" );
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exit( 1 );
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case 0:
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break;
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default:
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close( pfd[1] );
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socket_register_internal( sock, pfd[0] );
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sock->state = SCK_RESOLVING;
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conf_notifier( &sock->notify, 0, POLLIN );
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socket_expect_activity( sock, 1 );
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return;
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}
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#ifdef HAVE_IPV6
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struct addrinfo *res, hints = { 0 };
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hints.ai_family = AF_UNSPEC;
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hints.ai_socktype = SOCK_STREAM;
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hints.ai_flags = AI_ADDRCONFIG;
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infon( "Resolving %s... ", conf->host );
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if ((gaierr = getaddrinfo( conf->host, NULL, &hints, &sock->addrs ))) {
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error( "Error: Cannot resolve server '%s': %s\n", conf->host, gai_strerror( gaierr ) );
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socket_connect_bail( sock );
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return;
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int gaierr = getaddrinfo( sock->conf->host, NULL, &hints, &res );
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pipe_write( pfd[1], &gaierr, sizeof(gaierr) );
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if (gaierr)
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_exit( 1 );
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static_assert( sizeof(((struct addrinfo){ 0 }).ai_family) == sizeof(int), "unexpected size of ai_family" );
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static_assert( sizeof(struct in_addr) % sizeof(int) == 0, "unexpected size of struct in_addr" );
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static_assert( sizeof(struct in6_addr) % sizeof(int) == 0, "unexpected size of struct in6_addr" );
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int nbytes = 0;
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for (struct addrinfo *cres = res; cres; cres = cres->ai_next) {
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if (cres->ai_family == AF_INET) {
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nbytes += sizeof(int) + sizeof(struct in_addr);
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} else {
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assert( cres->ai_family == AF_INET6 );
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nbytes += sizeof(int) + sizeof(struct in6_addr);
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}
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}
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pipe_write( pfd[1], &nbytes, sizeof(nbytes) );
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for (struct addrinfo *cres = res; cres; cres = cres->ai_next) {
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pipe_write( pfd[1], &cres->ai_family, sizeof(int) );
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if (cres->ai_family == AF_INET)
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pipe_write( pfd[1], &((struct sockaddr_in *)cres->ai_addr)->sin_addr, sizeof(struct in_addr) );
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else
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pipe_write( pfd[1], &((struct sockaddr_in6 *)cres->ai_addr)->sin6_addr, sizeof(struct in6_addr) );
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}
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info( "\vok\n" );
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#else
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struct hostent *he;
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struct hostent *he = gethostbyname( sock->conf->host );
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int herrno = he ? 0 : h_errno;
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pipe_write( pfd[1], &herrno, sizeof(herrno) );
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if (!he)
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_exit( 1 );
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static_assert( sizeof(struct in_addr) % sizeof(int) == 0, "unexpected size of struct in_addr" );
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int nbytes = 0;
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for (char **addr = he->h_addr_list; *addr; addr++)
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nbytes += sizeof(struct in_addr);
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pipe_write( pfd[1], &nbytes, sizeof(nbytes) );
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for (char **addr = he->h_addr_list; *addr; addr++)
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pipe_write( pfd[1], *addr, sizeof(struct in_addr) );
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#endif
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_exit( 0 );
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}
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infon( "Resolving %s... ", conf->host );
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he = gethostbyname( conf->host );
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if (!he) {
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error( "Error: Cannot resolve server '%s': %s\n", conf->host, hstrerror( h_errno ) );
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static void
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pipe_read( int fd, void *buf, int len )
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{
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do {
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int didrd = read( fd, buf, len );
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if (didrd < 0) {
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sys_error( "read" );
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exit( 1 );
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}
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if (!didrd) {
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error( "read: unexpected EOF\n" );
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exit( 1 );
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}
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buf = ((char *)buf) + didrd;
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len -= didrd;
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} while (len);
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}
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static void
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socket_resolve_finalize( conn_t *sock )
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{
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int errcode;
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pipe_read( sock->fd, &errcode, sizeof(errcode) );
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if (errcode) {
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#ifdef HAVE_IPV6
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const char *err = gai_strerror( errcode );
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#else
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const char *err = hstrerror( errcode );
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#endif
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error( "Error: Cannot resolve server '%s': %s\n", sock->conf->host, err );
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socket_close_internal( sock );
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socket_connect_bail( sock );
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return;
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}
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info( "\vok\n" );
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sock->addrs = init_addrinfo( he );
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#endif
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sock->curr_addr = sock->addrs;
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int nbytes;
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pipe_read( sock->fd, &nbytes, sizeof(nbytes) );
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char *addrs = nfmalloc( nbytes );
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pipe_read( sock->fd, addrs, nbytes );
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sock->curr_addr = sock->addrs = addrs;
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sock->addrs_end = addrs + nbytes;
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socket_close_internal( sock ); // Get rid of the pipe
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socket_connect_one( sock );
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}
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}
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static void
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socket_resolve_timeout( conn_t *sock )
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{
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error( "Error: Cannot resolve server '%s': timeout.\n", sock->conf->host );
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socket_close_internal( sock );
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socket_connect_bail( sock );
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}
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static void
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socket_connect_one( conn_t *sock )
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{
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int s;
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#ifdef HAVE_IPV6
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struct addrinfo *ai;
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#else
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struct addr_info *ai;
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#endif
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if (!(ai = sock->curr_addr)) {
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char *ai = sock->curr_addr;
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if (ai == sock->addrs_end) {
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error( "No working address found for %s\n", sock->conf->host );
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socket_connect_bail( sock );
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return;
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}
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union {
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struct sockaddr any;
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struct sockaddr_in ip4;
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#ifdef HAVE_IPV6
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if (ai->ai_family == AF_INET6) {
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struct sockaddr_in6 *in6 = ((struct sockaddr_in6 *)ai->ai_addr);
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struct sockaddr_in6 ip6;
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#endif
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} addr;
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#ifdef HAVE_IPV6
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int fam = *(int *)ai;
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ai += sizeof(int);
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int addr_len;
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if (fam == AF_INET6) {
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addr_len = sizeof(addr.ip6);
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addr.ip6.sin6_addr = *(struct in6_addr *)ai;
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addr.ip6.sin6_flowinfo = 0;
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addr.ip6.sin6_scope_id = 0;
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ai += sizeof(struct in6_addr);
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} else {
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addr_len = sizeof(addr.ip4);
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#else
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const int fam = AF_INET;
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const int addr_len = sizeof(addr.ip4);
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{
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#endif
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addr.ip4.sin_addr = *(struct in_addr *)ai;
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ai += sizeof(struct in_addr);
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}
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sock->curr_addr = ai;
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#ifdef HAVE_IPV6
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if (fam == AF_INET6) {
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char sockname[64];
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in6->sin6_port = htons( sock->conf->port );
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inet_ntop( fam, &addr.ip6.sin6_addr, sockname, sizeof(sockname) );
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nfasprintf( &sock->name, "%s ([%s]:%hu)",
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sock->conf->host, inet_ntop( AF_INET6, &in6->sin6_addr, sockname, sizeof(sockname) ), sock->conf->port );
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sock->conf->host, sockname, sock->conf->port );
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} else
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#endif
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{
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struct sockaddr_in *in = ((struct sockaddr_in *)ai->ai_addr);
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in->sin_port = htons( sock->conf->port );
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nfasprintf( &sock->name, "%s (%s:%hu)",
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sock->conf->host, inet_ntoa( in->sin_addr ), sock->conf->port );
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sock->conf->host, inet_ntoa( addr.ip4.sin_addr ), sock->conf->port );
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}
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#ifdef HAVE_IPV6
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s = socket( ai->ai_family, SOCK_STREAM, 0 );
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#else
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s = socket( PF_INET, SOCK_STREAM, 0 );
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#endif
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int s = socket( fam, SOCK_STREAM, 0 );
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if (s < 0) {
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socket_connect_next( sock );
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return;
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@ -579,11 +686,9 @@ socket_connect_one( conn_t *sock )
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socket_open_internal( sock, s );
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infon( "Connecting to %s... ", sock->name );
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#ifdef HAVE_IPV6
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if (connect( s, ai->ai_addr, ai->ai_addrlen )) {
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#else
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if (connect( s, ai->ai_addr, sizeof(*ai->ai_addr) )) {
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#endif
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addr.any.sa_family = fam;
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addr.ip4.sin_port = htons( sock->conf->port ); // Aliased for ip6
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if (connect( s, &addr.any, addr_len )) {
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if (errno != EINPROGRESS) {
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socket_connect_failed( sock );
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return;
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@ -604,7 +709,6 @@ socket_connect_next( conn_t *conn )
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sys_error( "Cannot connect to %s", conn->name );
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free( conn->name );
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conn->name = NULL;
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conn->curr_addr = conn->curr_addr->ai_next;
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socket_connect_one( conn );
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}
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@ -618,10 +722,8 @@ socket_connect_failed( conn_t *conn )
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static void
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socket_connected( conn_t *conn )
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{
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if (conn->addrs) {
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freeaddrinfo( conn->addrs );
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free( conn->addrs );
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conn->addrs = NULL;
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}
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conf_notifier( &conn->notify, 0, POLLIN );
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socket_expect_activity( conn, 0 );
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conn->state = SCK_READY;
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@ -631,10 +733,8 @@ socket_connected( conn_t *conn )
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static void
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socket_cleanup_names( conn_t *conn )
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{
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if (conn->addrs) {
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freeaddrinfo( conn->addrs );
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free( conn->addrs );
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conn->addrs = NULL;
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}
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free( conn->name );
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conn->name = NULL;
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}
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@ -1106,6 +1206,11 @@ socket_fd_cb( int events, void *aux )
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{
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conn_t *conn = (conn_t *)aux;
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if (conn->state == SCK_RESOLVING) {
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socket_resolve_finalize( conn );
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return;
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}
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if ((events & POLLERR) || conn->state == SCK_CONNECTING) {
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int soerr;
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socklen_t selen = sizeof(soerr);
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@ -1168,7 +1273,9 @@ socket_timeout_cb( void *aux )
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{
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conn_t *conn = (conn_t *)aux;
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if (conn->state == SCK_CONNECTING) {
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if (conn->state == SCK_RESOLVING) {
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socket_resolve_timeout( conn );
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} else if (conn->state == SCK_CONNECTING) {
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errno = ETIMEDOUT;
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socket_connect_failed( conn );
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} else {
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|
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@ -57,11 +57,7 @@ typedef struct {
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int fd;
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int state;
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const server_conf_t *conf; /* needed during connect */
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#ifdef HAVE_IPV6
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struct addrinfo *addrs, *curr_addr; /* needed during connect */
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#else
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struct addr_info *addrs, *curr_addr; /* needed during connect */
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#endif
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char *addrs, *addrs_end, *curr_addr; // needed during connect; assumed to be int-aligned
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char *name;
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#ifdef HAVE_LIBSSL
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SSL *ssl;
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|
|||
Loading…
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Block a user