int tcp_response_waiting_client_close_process (Context *cont) {
const char *fn = "tcp_response_waiting_client_close_process()";
uint16_t length_buf;
int i;
syslog (LOG_DEBUG, "%s: start", fn);
i = read (cont->conn_sock, (u_char *) (&length_buf),
sizeof (uint16_t));
if (!i) /* SUCCESS */
return tcp_response_finish (cont);
if (i < sizeof (uint16_t)) {
/* read error */
syslog (LOG_INFO, "%s: read(): %m", fn);
return (response_abort (cont, -1));
}
/* redo query processing */
length_buf = ntohs (length_buf);
syslog (LOG_DEBUG, "%s: incoming length %d", fn, length_buf);
/* free old buffer */
if (cont->mesg.p)
free (cont->mesg.p);
/* allocate new buffer */
cont->mesg.p = malloc (length_buf);
if (!cont->mesg.p) {
cont->mesg_len = 0;
return (response_abort (cont, -1));
}
cont->mesg_len = length_buf;
cont->wp = cont->mesg.p;
cont->timeout = TCP_SRV_TIMEOUT;
/* renew timeout */
if (cont->tout)
cont->tout->handler = NULL;
if (context_timeout_register (cont, cont->timeout))
return (response_abort (cont, -1));
/*
* I/O event is not changed -- tcp_conn_in,
* go back to reading
*/
cont->process = tcp_response_reading_process;
cont->retry = tcp_response_reading_retry;
syslog (LOG_DEBUG, "%s: return, continue reading", fn);
/* SUCCESS, but not FINISHED yet */
return 0;
}
int tcp_response_readlen_process (Context *cont) {
const char *fn = "tcp_response_readlen_process()";
uint16_t length_buf;
syslog (LOG_DEBUG, "%s: start", fn);
/* renew timeout */
if (cont->tout)
cont->tout->handler = NULL;
if (context_timeout_register (cont, cont->timeout))
return (response_abort (cont, -1));
/* still use old input list -- data following */
/* read length buffer */
if (read (cont->conn_sock, (u_char *) (&length_buf),
sizeof (uint16_t)) < sizeof (uint16_t)) {
syslog (LOG_NOTICE, "%s: cannot read length TCP message", fn);
return (response_abort (cont, -1));
}
length_buf = ntohs (length_buf);
syslog (LOG_DEBUG, "%s: data length = %d", fn, length_buf);
/* free old buffer */
if (cont->mesg.p)
free (cont->mesg.p);
/* allocate new properly sized buffer */
cont->mesg.p = malloc (length_buf);
if (!cont->mesg.p)
return (response_abort (cont, -1));
cont->mesg_len = length_buf;
cont->wp = cont->mesg.p;
/* go next state */
cont->process = tcp_response_reading_process;
cont->retry = tcp_response_reading_retry;
/* SUCCESS */
return 0;
}
int tcp_response_recursive_process (Context *cont) {
const char *fn = "tcp_response_recursive_process()";
syslog (LOG_DEBUG, "%s: start", fn);
switch (recursive_process (cont)) {
case 0:
syslog (LOG_DEBUG, "%s: return, continue", fn);
/* SUCCESS */
return 0;
case 1:
assemble_response (cont);
if (cont->mesg_len < 0 || cont->mesg_len > MAX_STREAM) {
syslog (LOG_WARNING, "response message too big");
return (response_abort (cont, 1));
}
if (cont->tout)
cont->tout->handler = NULL;
if (context_timeout_register (cont, cont->timeout))
return (response_abort (cont, -1));
/* register output */
if (ev_tcp_out_register (cont->conn_sock, cont))
return (response_abort (cont, -1));
/* change the state */
cont->process = tcp_response_writing_process;
cont->retry = tcp_response_writing_retry;
cont->wp = NULL;
syslog (LOG_DEBUG, "%s: return, finish", fn);
/* SUCCESS */
return 0;
default:
return (response_abort (cont, -1));
}
}
/*
* When a new query is received over a UDP socket from a client, the
* udp_response state machine is started. See also ev_udp_in_read(),
* which is the only place from where udp_response_start() is called.
*
* udp_response_start() starts a new transaction. First creates a new
* root context for it, and starts the forwarding of the original query.
*
* forwarding is performed by starting a new child request, which
* if all goes well result in some resource records in our context.
*
* when the forwarded request finished successfully, udp_response_finish()
* is responsible for interpreting it and sending a response back to the client.
*
*/
int udp_response_start (u_char *mesg_buf, int mesg_len, struct sockaddr *sa_p,
Nia *inif) {
const char *fn = "udp_response_start()";
Context *cont;
syslog (LOG_DEBUG, "%s: start", fn);
/* create context */
cont = context_create();
if (!cont)
return (response_abort (cont, -1));
cont->mesg.p = mesg_buf;
cont->mesg_len = mesg_len;
cont->wp = mesg_buf + mesg_len; /* just after the answer section */
cont->q_id = cont->mesg.hdr->id;
cont->netifaddr = nia_copy (inif);
memcpy (cont->peer, sa_p, SOCKADDR_SIZEOF(*sa_p));
if (cont->mesg.hdr->opcode == OP_QUERY) {
syslog (LOG_DEBUG, "%s: OPCODE = OP_QUERY", fn);
/* query-response specific variables */
cont->process = udp_response_recursive_process;
cont->retry = udp_response_recursive_retry;
/* do the forwarding, send request to forwarder */
switch (request_start (cont, QUERY_TCP)) {
case 0:
/* We got a response */
return (0);
case 1:
/* Something wrong with the query */
cont->mesg.hdr->rcode = RC_FMTERR;
return (udp_response_finish (cont));
default:
/* We failed ourselves somehow */
cont->mesg.hdr->rcode = RC_SERVERERR;
return (udp_response_finish (cont));
}
} else {
syslog (LOG_NOTICE, "%s: OPCODE unknown(%d)", fn,
cont->mesg.hdr->opcode);
cont->mesg.hdr->rcode = RC_NIMP;
return udp_response_finish (cont);
}
/* NOTREACHED */
return 0;
}
int tcp_response_start (int sock, struct sockaddr *sa_p) {
const char *fn = "tcp_response_start()";
Context *cont;
syslog (LOG_DEBUG, "%s: start", fn);
cont = context_create();
if (!cont)
return (response_abort (cont, -1));
cont->process = tcp_response_readlen_process;
cont->retry = tcp_response_readlen_retry;
memcpy (cont->peer, sa_p, SOCKADDR_SIZEOF(*sa_p));
cont->conn_sock = sock;
cont->timeout = TCP_SRV_TIMEOUT;
if (!context_timeout_register (cont, cont->timeout) &&
!ev_tcp_conn_in_register (cont->conn_sock, cont))
return 0; /* SUCCESS */
return (response_abort (cont, -1));
}
int tcp_response_writing_process (Context *cont) {
const char *fn = "tcp_response_writing_process()";
syslog (LOG_DEBUG, "%s: start", fn);
/* renew timeout */
if (cont->tout)
cont->tout->handler = NULL;
if (context_timeout_register (cont, cont->timeout))
return (response_abort (cont, -1));
switch (tcp_writemesg (cont, cont->conn_sock)) {
case 0:
/* continue this process */
syslog (LOG_DEBUG, "%s: return, continue", fn);
/* SUCCESS */
return 0;
case 1:
/* all data written */
cont->process = tcp_response_waiting_client_close_process;
cont->retry = tcp_response_waiting_client_close_retry;
/* stop output and waiting for input */
ev_tcp_out_remove (cont->conn_sock);
ev_tcp_conn_in_register (cont->conn_sock, cont);
syslog (LOG_DEBUG, "%s: return, finish", fn);
/* SUCCESS */
return 0;
default:
/* FAILURE */
return (response_abort (cont, -1));
}
}
int udp_response_recursive_retry (Context *cont) {
syslog (LOG_ERR, "udp_response_recursive_retry should not be called.");
return response_abort (cont, 0);
}
int udp_response_finish (Context *cont) {
const char *fn = "udp_response_finish()";
int len;
syslog (LOG_DEBUG, "%s: start", fn);
/*
* We trim the response down if it doesn't fit in a default UDP
* data in a somewhat crude way. Could be smarter, like trim
* A records from response for pure IPv6 queries and so. See, if
* it is needed often. Maybe better to support EDNS0 option instead.
*
* RFC1035 says we should truncate the message to 512 bytes and set the
* tr bit in the header, but it is really vague on when a response does
* not fit. RFC2181 clarifies the use of the tr bit in section 9.
*
* Note that similar logic is still present in mesg_assemble() in
* ne_mesg.c (may disappear if we add the logic to assemble_response()
* instead).
*/
assemble_response (cont);
if (cont->mesg_len < 0 || cont->mesg_len > MAX_PACKET) {
/* put the message on a diet */
list_destroy (cont->ar_list, rrset_freev);
cont->ar_list = NULL;
syslog (LOG_DEBUG, "Overweight, dropping additional section");
assemble_response (cont);
}
if (cont->mesg_len < 0 || cont->mesg_len > MAX_PACKET) {
/*
* ok, water adn bread then then. shuold check
* RFCs, it may be better to return error msg
* instead of slimmed answer.
*/
list_destroy (cont->ns_list, rrset_freev);
cont->ns_list = NULL;
syslog (LOG_DEBUG, "Overweight, dropping authority section");
assemble_response (cont);
}
if (cont->mesg_len < 0 || cont->mesg_len > MAX_PACKET) {
/* ok, nothing viable left, so die */
list_destroy (cont->an_list, rrset_freev);
cont->an_list = NULL;
assemble_response (cont);
cont->mesg.hdr->tc = 1;
syslog (LOG_WARNING, "Obese, answers too big for UDP");
}
if (cont->mesg_len < 0 || cont->mesg_len > MAX_PACKET) {
syslog (LOG_ERR, "Even error msg is too big for UDP");
return (response_abort (cont, 1));
}
/* send the answer */
len = net_mesg_send (cont->netifaddr, cont->mesg.p, cont->mesg_len,
cont->peer);
if (len < cont->mesg_len) {
syslog (LOG_NOTICE, "failed to send message.");
return (response_abort (cont, -1));
}
context_destroy (cont);
return 0;
}
int tcp_response_reading_process (Context *cont) {
const char *fn = "tcp_response_reading_process()";
int len;
syslog (LOG_DEBUG, "%s: start", fn);
if (cont->tout)
cont->tout->handler = NULL;
if (context_timeout_register (cont, cont->timeout))
return(response_abort (cont, -1));
len = read (cont->conn_sock, cont->wp,
cont->mesg_len - (cont->wp - cont->mesg.p));
if (len <= 0)
return(response_abort (cont, -1));
cont->wp += len;
if (cont->wp < (cont->mesg.p + cont->mesg_len)) {
syslog (LOG_DEBUG, "%s: left %zd bytes -- continue.", fn,
(cont->mesg.p + cont->mesg_len) - cont->wp);
/* SUCCESS */
return 0; /* the processing continues ... */
}
/* all data has been read now */
ev_tcp_conn_in_remove (cont->conn_sock);
if (cont->mesg.hdr->opcode == OP_QUERY) {
if (cont->tout)
cont->tout->handler = NULL;
/*
* don't register input list,
* child context takes input
*/
switch (request_start (cont, QUERY_TCP)) {
case 0:
/*
* We forwarded the request without problems,
* asycnhronously awaiting a response.
* goto recursive_processing state
* clear events, child will call me then
*/
if (cont->tout)
cont->tout->handler = NULL;
cont->process = tcp_response_recursive_process;
cont->retry = tcp_response_recursive_retry;
/* SUCCESS */
return 0;
case 1:
/* Something wrong with the query */
syslog (LOG_NOTICE, "%s: Request failed", fn);
cont->mesg.hdr->rcode = RC_FMTERR;
default:
/* totd failed itself somehow */
syslog (LOG_NOTICE, "%s: Totd failed", fn);
cont->mesg.hdr->rcode = RC_SERVERERR;
}
} else
cont->mesg.hdr->rcode = RC_NIMP;
/*
* Not OP_QUERY or Request failed brings us here
*
* Go to writing state. Timeout already done in this function
* Register new output event
*/
if (!ev_tcp_out_register (cont->conn_sock, cont)) {
assemble_response (cont);
/* state change */
cont->process = tcp_response_writing_process;
cont->retry = tcp_response_writing_retry;
cont->wp = NULL;
syslog (LOG_DEBUG, "%s: end (writing:)", fn);
/* SUCCESS */
return 0;
}
/* FAILURE */
return (response_abort (cont, -1));
}
int tcp_response_readlen_retry (Context *cont) {
const char *fn = "tcp_response_readlen_retry()";
syslog (LOG_NOTICE, "%s: connection does not respond. closing.", fn);
return (response_abort (cont, -1));
}
int tcp_response_waiting_client_close_retry (Context *cont) {
return (response_abort (cont, 0));
}
int tcp_response_writing_retry (Context *cont) {
return (response_abort (cont, -1));
}
int tcp_response_recursive_retry (Context *cont) {
return (response_abort (cont, -1));
}
