/*
* barebox RATP implementation.
* This is the barebox implementation for the Reliable Asynchronous
* Transfer Protocol (RATP) as described in RFC916.
*
* Copyright (C) 2015 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) "ratp: " fmt
#include <common.h>
#include <malloc.h>
#include <getopt.h>
#include <ratp.h>
#include <crc.h>
#include <clock.h>
#include <asm/unaligned.h>
/*
* RATP packet format:
*
* Byte No.
*
* +-------------------------------+
* | |
* 1 | Synch Leader | Hex 01
* | |
* +-------------------------------+
* | S | A | F | R | S | A | E | S |
* 2 | Y | C | I | S | N | N | O | O | Control
* | N | K | N | T | | | R | |
* +-------------------------------+
* | |
* 3 | Data length (0-255) |
* | |
* +-------------------------------+
* | |
* 4 | Header Checksum |
* | |
* +-------------------------------+
*
*/
struct ratp_header {
uint8_t synch;
uint8_t control;
uint8_t data_length;
uint8_t cksum;
};
#define RATP_CONTROL_SO (1 << 0)
#define RATP_CONTROL_EOR (1 << 1)
#define RATP_CONTROL_AN (1 << 2)
#define RATP_CONTROL_SN (1 << 3)
#define RATP_CONTROL_RST (1 << 4)
#define RATP_CONTROL_FIN (1 << 5)
#define RATP_CONTROL_ACK (1 << 6)
#define RATP_CONTROL_SYN (1 << 7)
enum ratp_state {
RATP_STATE_LISTEN,
RATP_STATE_SYN_SENT,
RATP_STATE_SYN_RECEIVED,
RATP_STATE_ESTABLISHED,
RATP_STATE_FIN_WAIT,
RATP_STATE_LAST_ACK,
RATP_STATE_CLOSING,
RATP_STATE_TIME_WAIT,
RATP_STATE_CLOSED,
};
struct ratp_message {
void *buf;
size_t len;
struct list_head list;
void (*complete)(void *ctx, int status);
void *complete_ctx;
int eor;
};
static char *ratp_state_str[] = {
[RATP_STATE_LISTEN] = "LISTEN",
[RATP_STATE_SYN_SENT] = "SYN_SENT",
[RATP_STATE_SYN_RECEIVED] = "SYN_RECEIVED",
[RATP_STATE_ESTABLISHED] = "ESTABLISHED",
[RATP_STATE_FIN_WAIT] = "FIN_WAIT",
[RATP_STATE_LAST_ACK] = "LAST_ACK",
[RATP_STATE_CLOSING] = "CLOSING",
[RATP_STATE_TIME_WAIT] = "TIME_WAIT",
[RATP_STATE_CLOSED] = "CLOSED",
};
struct ratp_internal {
struct ratp *ratp;
enum ratp_state state;
int sn_sent;
int sn_received;
int active;
void *recvbuf;
void *sendbuf;
int sendbuf_len;
struct list_head recvmsg;
struct list_head sendmsg;
struct ratp_message *sendmsg_current;
uint64_t timewait_timer_start;
uint64_t retransmission_timer_start;
int max_retransmission;
int retransmission_count;
int srtt;
int rto;
int status;
int in_ratp;
};
static bool ratp_sn(struct ratp_header *hdr)
{
return hdr->control & RATP_CONTROL_SN ? 1 : 0;
}
static bool ratp_an(struct ratp_header *hdr)
{
return hdr->control & RATP_CONTROL_AN ? 1 : 0;
}
#define ratp_set_sn(sn) (sn ? RATP_CONTROL_SN : 0)
#define ratp_set_an(an) (an ? RATP_CONTROL_AN : 0)
#define ratp_set_next_sn(sn) (((sn + 1) % 2) ? RATP_CONTROL_SN : 0)
#define ratp_set_next_an(an) (((an + 1) % 2) ? RATP_CONTROL_AN : 0)
static inline int ratp_header_ok(struct ratp_internal *ri, struct ratp_header *h)
{
uint8_t cksum;
int ret;
cksum = h->control;
cksum += h->data_length;
cksum += h->cksum;
ret = cksum == 0xff ? 1 : 0;
if (ret)
pr_vdebug("Header ok\n");
else
pr_vdebug("Header cksum failed: %02x\n", cksum);
return ret;
}
static bool ratp_has_data(struct ratp_header *hdr)
{
if (hdr->control & RATP_CONTROL_SO)
return 1;
if (!(hdr->control & (RATP_CONTROL_SYN | RATP_CONTROL_RST | RATP_CONTROL_FIN)) && hdr->data_length)
return 1;
return 0;
}
static void ratp_print_header(struct ratp_internal *ri, struct ratp_header *hdr,
const char *prefix)
{
uint8_t control = hdr->control;
pr_debug("%s>%s %s %s %s %s %s %s %s< len: %-3d\n",
prefix,
control & RATP_CONTROL_SO ? "so" : "--",
control & RATP_CONTROL_EOR ? "eor" : "---",
control & RATP_CONTROL_AN ? "an" : "--",
control & RATP_CONTROL_SN ? "sn" : "--",
control & RATP_CONTROL_RST ? "rst" : "---",
control & RATP_CONTROL_FIN ? "fin" : "---",
control & RATP_CONTROL_ACK ? "ack" : "---",
control & RATP_CONTROL_SYN ? "syn" : "---",
hdr->data_length);
#ifdef VERBOSE_DEBUG
if (hdr->data_length)
memory_display(hdr + 1, 0, hdr->data_length, 1, 0);
#endif
}
static void ratp_create_packet(struct ratp_internal *ri, struct ratp_header *hdr,
uint8_t control, uint8_t length)
{
hdr->synch = 0x1;
hdr->control = control;
hdr->data_length = length;
hdr->cksum = (control + length) ^ 0xff;
}
static void ratp_state_change(struct ratp_internal *ri, enum ratp_state state)
{
pr_debug("state %-10s -> %-10s\n", ratp_state_str[ri->state],
ratp_state_str[state]);
ri->state = state;
}
#define RATP_CONTROL_SO (1 << 0)
#define RATP_CONTROL_EOR (1 << 1)
#define RATP_CONTROL_AN (1 << 2)
#define RATP_CONTROL_SN (1 << 3)
#define RATP_CONTROL_RST (1 << 4)
#define RATP_CONTROL_FIN (1 << 5)
#define RATP_CONTROL_ACK (1 << 6)
#define RATP_CONTROL_SYN (1 << 7)
static int ratp_send_pkt(struct ratp_internal *ri, void *pkt, int length)
{
struct ratp_header *hdr = (void *)pkt;
ratp_print_header(ri, hdr, "send");
if (ratp_has_data(hdr) ||
(hdr->control & (RATP_CONTROL_SYN | RATP_CONTROL_RST | RATP_CONTROL_FIN))) {
memcpy(ri->sendbuf, pkt, length);
ri->sn_sent = ratp_sn(hdr);
ri->sendbuf_len = length;
ri->retransmission_timer_start = get_time_ns();
ri->retransmission_count = 0;
}
return ri->ratp->send(ri->ratp, pkt, length);
}
static int ratp_send_hdr(struct ratp_internal *ri, uint8_t control)
{
struct ratp_header hdr = {};
ratp_create_packet(ri, &hdr, control, 0);
return ratp_send_pkt(ri, &hdr, sizeof(hdr));
}
static int ratp_recv_char(struct ratp_internal *ri, uint8_t *data, int poll_timeout_ms)
{
uint64_t start;
int ret;
start = get_time_ns();
while (1) {
ret = ri->ratp->recv(ri->ratp, data);
if (ret < 0 && ret != -EAGAIN)
return ret;
if (ret == 0)
return 0;
if (is_timeout(start, poll_timeout_ms * MSECOND))
return -EAGAIN;
}
}
static int ratp_recv_pkt_header(struct ratp_internal *ri, struct ratp_header *hdr,
int poll_timeout_ms)
{
int ret;
uint8_t buf;
do {
ret = ratp_recv_char(ri, &buf, 0);
if (ret < 0)
return ret;
hdr->synch = buf;
} while (hdr->synch != 1);
ret = ratp_recv_char(ri, &buf, poll_timeout_ms);
if (ret < 0)
return ret;
hdr->control = buf;
ret = ratp_recv_char(ri, &buf, poll_timeout_ms);
if (ret < 0)
return ret;
hdr->data_length = buf;
ret = ratp_recv_char(ri, &buf, poll_timeout_ms);
if (ret < 0)
return ret;
hdr->cksum = buf;
if (!ratp_header_ok(ri, hdr))
return -EAGAIN;
return 0;
}
static int ratp_recv_pkt_data(struct ratp_internal *ri, void *data, uint8_t len,
int poll_timeout_ms)
{
uint16_t crc_expect, crc_read;
int ret, i;
for (i = 0; i < len + 2; i++) {
ret = ratp_recv_char(ri, data + i, poll_timeout_ms);
if (ret < 0)
return ret;
}
crc_expect = crc_itu_t(0, data, len);
crc_read = get_unaligned_be16(data + len);
if (crc_expect != crc_read) {
pr_vdebug("Wrong CRC: expected: 0x%04x, got 0x%04x\n",
crc_expect, crc_read);
return -EBADMSG;
} else {
pr_vdebug("correct CRC: 0x%04x\n", crc_expect);
}
return 0;
}
static int ratp_recv_pkt(struct ratp_internal *ri, void *pkt, int poll_timeout_ms)
{
struct ratp_header *hdr = pkt;
void *data = pkt + sizeof(struct ratp_header);
int ret;
ret = ratp_recv_pkt_header(ri, hdr, poll_timeout_ms);
if (ret < 0)
return ret;
if (hdr->control & (RATP_CONTROL_SO | RATP_CONTROL_RST | RATP_CONTROL_SYN |
RATP_CONTROL_FIN))
return 0;
if (hdr->data_length) {
ret = ratp_recv_pkt_data(ri, data, hdr->data_length,
poll_timeout_ms);
if (ret)
return ret;
}
return 0;
}
static bool ratp_an_expected(struct ratp_internal *ri, struct ratp_header *hdr)
{
return ratp_an(hdr) == (ri->sn_sent + 1) % 2;
}
static bool ratp_sn_expected(struct ratp_internal *ri, struct ratp_header *hdr)
{
return ratp_sn(hdr) == (ri->sn_received + 1) % 2;
}
static int ratp_send_ack(struct ratp_internal *ri, struct ratp_header *hdr)
{
uint8_t control;
int ret;
control = ratp_set_sn(ratp_an(hdr)) |
ratp_set_next_an(ratp_sn(hdr)) |
RATP_CONTROL_ACK;
ret = ratp_send_hdr(ri, control);
if (ret)
return ret;
return 0;
}
static int ratp_send_next_data(struct ratp_internal *ri)
{
uint16_t crc;
uint8_t control;
struct ratp_header *hdr;
uint8_t *data;
int pktlen;
struct ratp_message *msg;
int len;
if (ri->sendmsg_current) {
pr_err("%s: busy\n", __func__);
return -EBUSY;
}
if (list_empty(&ri->sendmsg))
return 0;
msg = list_first_entry(&ri->sendmsg, struct ratp_message, list);
ri->sendmsg_current = msg;
list_del(&msg->list);
len = msg->len;
control = ratp_set_next_sn(ri->sn_sent) |
ratp_set_next_an(ri->sn_received) |
RATP_CONTROL_ACK;
hdr = msg->buf;
data = (uint8_t *)(hdr + 1);
if (msg->eor)
control |= RATP_CONTROL_EOR;
pktlen = sizeof(struct ratp_header);
if (len > 1) {
pktlen += len + 2;
crc = crc_itu_t(0, data, len);
put_unaligned_be16(crc, data + len);
} else if (len == 1) {
control |= RATP_CONTROL_SO;
len = *data;
}
ratp_create_packet(ri, hdr, control, len);
ri->retransmission_count = 0;
ratp_send_pkt(ri, msg->buf, pktlen);
return 0;
}
static void ratp_start_time_wait_timer(struct ratp_internal *ri)
{
ri->timewait_timer_start = get_time_ns();
}
static void ratp_msg_done(struct ratp_internal *ri, struct ratp_message *msg, int status)
{
int alpha, beta, rtt;
if (!status) {
rtt = (unsigned long)(get_time_ns() - ri->retransmission_timer_start) / MSECOND;
alpha = 8;
beta = 15;
ri->srtt = (alpha * ri->srtt + (10 - alpha) * rtt) / 10;
ri->rto = max(200, beta * ri->srtt / 10);
pr_debug("%s: done. SRTT: %dms RTO: %dms status: %d\n",
__func__, ri->srtt, ri->rto, ri->status);
}
if (msg->complete)
msg->complete(msg->complete_ctx, status);
free(msg->buf);
free(msg);
}
/*
* This procedure details the behavior of the LISTEN state. First
* check the packet for the RST flag. If it is set then packet is
* discarded and ignored, return and continue the processing
* associated with this state.
*
* We assume now that the RST flag was not set. Check the packet
* for the ACK flag. If it is set we have an illegal condition
* since no connection has yet been opened. Send a RST packet
* with the correct response SN value:
*
* <SN=received AN><CTL=RST>
*
* Return to the current state without any further processing.
*
* We assume now that neither the RST nor the ACK flags were set.
* Check the packet for a SYN flag. If it is set then an attempt
* is being made to open a connection. Create a TCB for this
* connection. The sender has placed its MDL in the LENGTH field,
* also specified is the sender's initial SN value. Retrieve and
* place them into the TCB. Note that the presence of the SO flag
* is ignored since it has no meaning when either of the SYN, RST,
* or FIN flags are set.
*
* Send a SYN packet which acknowledges the SYN received. Choose
* the initial SN value and the MDL for this end of the
* connection:
*
* <SN=0><AN=received SN+1 modulo 2><CTL=SYN, ACK><LENGTH=MDL>
*
* and go to the RATP_STATE_SYN_RECEIVED state without any further
* processing.
*
* Any packet not satisfying the above tests is discarded and
* ignored. Return to the current state without any further
* processing.
*/
static void ratp_behaviour_a(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (hdr->control & RATP_CONTROL_RST)
return;
if (hdr->control & RATP_CONTROL_ACK) {
uint8_t control = RATP_CONTROL_RST;
if (hdr->control & RATP_CONTROL_AN)
control |= RATP_CONTROL_SN;
ratp_send_hdr(ri, control);
return;
}
if (hdr->control & RATP_CONTROL_SYN) {
struct ratp_header synack = {};
uint8_t control = RATP_CONTROL_SYN | RATP_CONTROL_ACK;
if (!(hdr->control & RATP_CONTROL_SN))
control |= RATP_CONTROL_AN;
ratp_create_packet(ri, &synack, control, 255);
ratp_send_pkt(ri, &synack, sizeof(synack));
ratp_state_change(ri, RATP_STATE_SYN_RECEIVED);
}
}
/*
* This procedure represents the behavior of the SYN-SENT state
* and is entered when this end of the connection decides to
* execute an active OPEN.
*
* First, check the packet for the ACK flag. If the ACK flag is
* set then check to see if the AN value was as expected. If it
* was continue below. Otherwise the AN value was unexpected. If
* the RST flag was set then discard the packet and return to the
* current state without any further processing, else send a
* reset:
*
* <SN=received AN><CTL=RST>
*
* Discard the packet and return to the current state without any
* further processing.
*
* At this point either the ACK flag was set and the AN value was
* as expected or ACK was not set. Second, check the RST flag.
* If the RST flag is set there are two cases:
*
* . If the ACK flag is set then discard the packet, flush the
* retransmission queue, inform the user "Error: Connection
* refused", delete the TCB, and go to the CLOSED state without
* any further processing.
*
* 2. If the ACK flag was not set then discard the packet and
* return to this state without any further processing.
*
* At this point we assume the packet contained an ACK which was
* Ok, or there was no ACK, and there was no RST. Now check the
* packet for the SYN flag. If the ACK flag was set then our SYN
* has been acknowledged. Store MDL received in the TCB. At this
* point we are technically in the ESTABLISHED state. Send an
* acknowledgment packet and any initial data which is queued to
* send:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK><DATA>
*
* Go to the ESTABLISHED state without any further processing.
*
* If the SYN flag was set but the ACK was not set then the other
* end of the connection has executed an active open also.
* Acknowledge the SYN, choose your MDL, and send:
*
* <SN=0><AN=received SN+1 modulo 2><CTL=SYN, ACK><LENGTH=MDL>
*
* Go to the SYN-RECEIVED state without any further processing.
*
* Any packet not satisfying the above tests is discarded and
* ignored. Return to the current state without any further
* processing.
*/
static void ratp_behaviour_b(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if ((hdr->control & RATP_CONTROL_ACK) && !ratp_an_expected(ri, hdr)) {
if (!(hdr->control & RATP_CONTROL_RST)) {
uint8_t control;
control = RATP_CONTROL_RST |
ratp_set_sn(ratp_an(hdr));
ratp_send_hdr(ri, control);
}
return;
}
if (hdr->control & RATP_CONTROL_RST) {
if (hdr->control & RATP_CONTROL_ACK) {
ri->status = -ECONNREFUSED;
pr_debug("Connection refused\n");
ratp_state_change(ri, RATP_STATE_CLOSED);
}
return;
}
if (hdr->control & RATP_CONTROL_SYN) {
uint8_t control;
ri->sn_received = ratp_sn(hdr);
if (hdr->control & RATP_CONTROL_ACK) {
ratp_state_change(ri, RATP_STATE_ESTABLISHED);
if (list_empty(&ri->sendmsg) || ri->sendmsg_current)
ratp_send_ack(ri, hdr);
else
ratp_send_next_data(ri);
} else {
struct ratp_header synack = {};
control = ratp_set_next_an(ratp_sn(hdr)) |
RATP_CONTROL_SYN |
RATP_CONTROL_ACK;
ratp_create_packet(ri, &synack, control, 255);
ratp_send_pkt(ri, &synack, sizeof(synack));
ratp_state_change(ri, RATP_STATE_SYN_RECEIVED);
}
}
}
/*
* Examine the received SN field value. If the SN value was
* expected then return and continue the processing associated
* with this state.
*
* We now assume the SN value was not what was expected.
*
* If either RST or FIN were set discard the packet and return to
* the current state without any further processing.
*
* If neither RST nor FIN flags were set it is assumed that this
* packet is a duplicate of one already received. Send an ACK
* back:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
*
* Discard the duplicate packet and return to the current state
* without any further processing.
*/
static int ratp_behaviour_c1(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
int ret;
pr_debug("%s\n", __func__);
if (ratp_sn_expected(ri, hdr)) {
pr_vdebug("%s: sn is expected\n", __func__);
return 0;
}
if (!(hdr->control & RATP_CONTROL_RST) &&
!(hdr->control & RATP_CONTROL_FIN)) {
ret = ratp_send_ack(ri, hdr);
if (ret)
return ret;
}
return 1;
}
/*
* Examine the received SN field value. If the SN value was
* expected then return and continue the processing associated
* with this state.
*
* We now assume the SN value was not what was expected.
*
* If either RST or FIN were set discard the packet and return to
* the current state without any further processing.
*
* If SYN was set we assume that the other end crashed and has
* attempted to open a new connection. We respond by sending a
* legal reset:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=RST, ACK>
*
* This will cause the other end, currently in the SYN-SENT state,
* to close. Flush the retransmission queue, inform the user
* "Error: Connection reset", discard the packet, delete the TCB,
* and go to the CLOSED state without any further processing.
*
* If neither RST, FIN, nor SYN flags were set it is assumed that
* this packet is a duplicate of one already received. Send an
* ACK back:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
*
* Discard the duplicate packet and return to the current state
* without any further processing.
*/
static int ratp_behaviour_c2(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
int ret;
pr_debug("%s\n", __func__);
if (ratp_sn_expected(ri, hdr))
return 0;
if ((hdr->control & RATP_CONTROL_RST) ||
(hdr->control & RATP_CONTROL_FIN))
return 1;
if (hdr->control & RATP_CONTROL_SYN) {
uint8_t control;
ri->status = -ECONNRESET;
pr_debug("Error: Connection reset\n");
control = RATP_CONTROL_RST | RATP_CONTROL_ACK |
ratp_set_sn(ratp_an(hdr)) | ratp_set_next_an(ratp_sn(hdr));
ratp_send_hdr(ri, control);
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
pr_debug("Sending ack for duplicate message\n");
ret = ratp_send_ack(ri, hdr);
if (ret)
return ret;
return 1;
}
/*
* The packet is examined for a RST flag. If RST is not set then
* return and continue the processing associated with this state.
*
* RST is now assumed to have been set. If the connection was
* originally initiated from the LISTEN state (it was passively
* opened) then flush the retransmission queue, discard the
* packet, and go to the LISTEN state without any further
* processing.
*
* If instead the connection was initiated actively (came from the
* SYN-SENT state) then flush the retransmission queue, inform the
* user "Error: Connection refused", discard the packet, delete
* the TCB, and go to the CLOSED state without any further
* processing.
*/
static int ratp_behaviour_d1(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_RST))
return 0;
if (!(ri->active)) {
ratp_state_change(ri, RATP_STATE_LISTEN);
return 1;
}
ri->status = -ECONNREFUSED;
pr_debug("Error: connection refused\n");
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
/*
* The packet is examined for a RST flag. If RST is not set then
* return and continue the processing associated with this state.
*
* RST is now assumed to have been set. Any data remaining to be
* sent is flushed. The retransmission queue is flushed, the user
* is informed "Error: Connection reset.", discard the packet,
* delete the TCB, and go to the CLOSED state without any further
* processing.
*/
static int ratp_behaviour_d2(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_RST))
return 0;
ri->status = -ECONNRESET;
pr_debug("connection reset\n");
return 0;
}
/*
* The packet is examined for a RST flag. If RST is not set then
* return and continue the processing associated with this state.
*
* RST is now assumed to have been set. Discard the packet,
* delete the TCB, and go to the CLOSED state without any further
* processing.
*/
static int ratp_behaviour_d3(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_RST))
return 0;
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
/*
* Check the presence of the SYN flag. If the SYN flag is not set
* then return and continue the processing associated with this
* state.
*
* We now assume that the SYN flag was set. The presence of a SYN
* here is an error. Flush the retransmission queue, send a legal
* RST packet.
*
* If the ACK flag was set then send:
*
* <SN=received AN><CTL=RST>
*
* If the ACK flag was not set then send:
*
* <SN=0><CTL=RST>
*
* The user should receive the message "Error: Connection reset.",
* then delete the TCB and go to the CLOSED state without any
* further processing.
*/
static int ratp_behaviour_e(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
uint8_t control;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_SYN))
return 0;
ri->status = -ECONNRESET;
control = RATP_CONTROL_RST;
if (hdr->control & RATP_CONTROL_ACK)
control |= ratp_set_sn(ratp_an(hdr));
ratp_send_hdr(ri, control);
pr_debug("connection reset\n");
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
/*
* Check the presence of the ACK flag. If ACK is not set then
* discard the packet and return without any further processing.
*
* We now assume that the ACK flag was set. If the AN field value
* was as expected then return and continue the processing
* associated with this state.
*
* We now assume that the ACK flag was set and that the AN field
* value was unexpected. If the connection was originally
* initiated from the LISTEN state (it was passively opened) then
* flush the retransmission queue, discard the packet, and send a
* legal RST packet:
*
* <SN=received AN><CTL=RST>
*
* Then delete the TCB and go to the LISTEN state without any
* further processing.
*
* Otherwise the connection was initiated actively (came from the
* SYN-SENT state) then inform the user "Error: Connection
* refused", flush the retransmission queue, discard the packet,
* and send a legal RST packet:
*
* <SN=received AN><CTL=RST>
*
* Then delete the TCB and go to the CLOSED state without any
* further processing.
*/
static int ratp_behaviour_f1(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
uint8_t control;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_ACK))
return 1;
if (ratp_an_expected(ri, hdr))
return 0;
control = RATP_CONTROL_RST | ratp_set_sn(ratp_an(hdr));
ratp_send_hdr(ri, control);
if (ri->active) {
ratp_state_change(ri, RATP_STATE_CLOSED);
ri->status = -ECONNREFUSED;
pr_debug("connection refused\n");
} else {
ratp_state_change(ri, RATP_STATE_LISTEN);
}
return 1;
}
/*
* Check the presence of the ACK flag. If ACK is not set then
* discard the packet and return without any further processing.
*
* We now assume that the ACK flag was set. If the AN field value
* was as expected then flush the retransmission queue and inform
* the user with an "Ok" if a buffer has been entirely
* acknowledged. Another packet containing data may now be sent.
* Return and continue the processing associated with this state.
*
* We now assume that the ACK flag was set and that the AN field
* value was unexpected. This is assumed to indicate a duplicate
* acknowledgment. It is ignored, return and continue the
* processing associated with this state.
*/
static int ratp_behaviour_f2(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_ACK))
return 1;
if (ratp_an_expected(ri, hdr)) {
pr_debug("Data succesfully sent\n");
if (ri->sendmsg_current)
ratp_msg_done(ri, ri->sendmsg_current, 0);
ri->sendmsg_current = NULL;
return 0;
} else {
pr_vdebug("%s: an not expected\n", __func__);
}
return 0;
}
/*
* Check the presence of the ACK flag. If ACK is not set then
* discard the packet and return without any further processing.
*
* We now assume that the ACK flag was set. If the AN field value
* was as expected then continue the processing associated with
* this state.
*
* We now assume that the ACK flag was set and that the AN field
* value was unexpected. This is ignored, return and continue
* with the processing associated with this state.
*/
static int ratp_behaviour_f3(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_ACK))
return 1;
return 0;
}
/*
* This procedure represents the behavior of the CLOSED state of a
* connection. All incoming packets are discarded. If the packet
* had the RST flag set take no action. Otherwise it is necessary
* to build a RST packet. Since this end is closed the other end
* of the connection has incorrect data about the state of the
* connection and should be so informed.
*
* If the ACK flag was set then send:
*
* <SN=received AN><CTL=RST>
*
* If the ACK flag was not set then send:
*
* <SN=0><AN=received SN+1 modulo 2><CTL=RST, ACK>
*
* After sending the reset packet return to the current state
* without any further processing.
*/
static int ratp_behaviour_g(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
uint8_t control;
pr_debug("%s\n", __func__);
if (hdr->control & RATP_CONTROL_RST)
return 0;
control = RATP_CONTROL_RST;
if (hdr->control & RATP_CONTROL_ACK)
control |= ratp_set_sn(ratp_an(hdr));
else
control |= ratp_set_next_an(ratp_sn(hdr)) | RATP_CONTROL_ACK;
ratp_send_hdr(ri, control);
return 0;
}
static int ratp_behaviour_i1(struct ratp_internal *ri, void *pkt);
/*
* Our SYN has been acknowledged. At this point we are
* technically in the ESTABLISHED state. Send any initial data
* which is queued to send:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK><DATA>
*
* Go to the ESTABLISHED state and execute procedure I1 to process
* any data which might be in this packet.
*
* Any packet not satisfying the above tests is discarded and
* ignored. Return to the current state without any further
* processing.
*/
static int ratp_behaviour_h1(struct ratp_internal *ri, void *pkt)
{
pr_debug("%s\n", __func__);
ratp_state_change(ri, RATP_STATE_ESTABLISHED);
/* If the input message has data (i.e. it is not just an ACK
* without data) then we need to send back an ACK ourselves,
* or even data if we have it pending. This is the same
* procedure done in i1, so just run it. */
return ratp_behaviour_i1 (ri, pkt);
}
/*
* Check the presence of the FIN flag. If FIN is not set then
* continue the processing associated with this state.
*
* We now assume that the FIN flag was set. This means the other
* end has decided to close the connection. Flush the
* retransmission queue. If any data remains to be sent then
* inform the user "Warning: Data left unsent." The user must
* also be informed "Connection closing." An acknowledgment for
* the FIN must be sent which also indicates this end is closing:
*
* <SN=received AN><AN=received SN + 1 modulo 2><CTL=FIN, ACK>
*
* Go to the LAST-ACK state without any further processing.
*/
static int ratp_behaviour_h2(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
uint8_t control;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_FIN))
return 0;
ri->status = -ENETDOWN;
control = ratp_set_sn(ratp_an(hdr)) |
ratp_set_next_an(ratp_sn(hdr)) |
RATP_CONTROL_FIN |
RATP_CONTROL_ACK;
ratp_send_hdr(ri, control);
ratp_state_change(ri, RATP_STATE_LAST_ACK);
ri->sn_received = ratp_sn(hdr);
return 1;
}
/*
* This state represents the final behavior of the FIN-WAIT state.
*
* If the packet did not contain a FIN we assume this packet is a
* duplicate and that the other end of the connection has not seen
* the FIN packet we sent earlier. Rely upon retransmission of
* our earlier FIN packet to inform the other end of our desire to
* close. Discard the packet and return without any further
* processing.
*
* At this point we have a packet which should contain a FIN. By
* the rules of this protocol an ACK of a FIN requires a FIN, ACK
* in response and no data. If the packet contains data we have
* detected an illegal condition. Send a reset:
* <SN=received AN><AN=received SN+1 modulo 2><CTL=RST, ACK>
*
* Discard the packet, flush the retransmission queue, inform the
* ser "Error: Connection reset.", delete the TCB, and go to the
* CLOSED state without any further processing.
*
* We now assume that the FIN flag was set and no data was
* contained in the packet. If the AN field value was expected
* then this packet acknowledges a previously sent FIN packet.
* The other end of the connection is then also assumed to be
* closing and expects an acknowledgment. Send an acknowledgment
* of the FIN:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
*
* Start the 2*SRTT timer associated with the TIME-WAIT state,
* discard the packet, and go to the TIME-WAIT state without any
* further processing.
*
* Otherwise the AN field value was unexpected. This indicates a
* simultaneous closing by both sides of the connection. Send an
* acknowledgment of the FIN:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
*
* Discard the packet, and go to the CLOSING state without any
* further processing.
*/
static int ratp_behaviour_h3(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
uint8_t control;
int expected;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_FIN))
return 1;
if (ratp_has_data(hdr)) {
control = ratp_set_sn(ratp_an(hdr)) |
ratp_set_next_an(ratp_sn(hdr)) |
RATP_CONTROL_RST |
RATP_CONTROL_ACK;
ratp_send_hdr(ri, control);
ri->status = -ECONNRESET;
pr_debug("Error: Connection reset\n");
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
control = ratp_set_sn(ratp_an(hdr)) |
ratp_set_next_an(ratp_sn(hdr)) |
RATP_CONTROL_ACK;
expected = ratp_an_expected(ri, hdr);
ratp_send_hdr(ri, control);
if (expected) {
ratp_state_change(ri, RATP_STATE_TIME_WAIT);
ratp_start_time_wait_timer(ri);
} else {
ratp_state_change(ri, RATP_STATE_CLOSING);
}
return 1;
}
/*
* This state represents the final behavior of the LAST-ACK state.
*
* If the AN field value is expected then this ACK is in response
* to the FIN, ACK packet recently sent. This is the final
* acknowledging message indicating both side's agreement to close
* the connection. Discard the packet, flush all queues, delete
* the TCB, and go to the CLOSED state without any further
* processing.
*
* Otherwise the AN field value was unexpected. Discard the
* packet and remain in the current state without any further
* processing.
*/
static int ratp_behaviour_h4(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (ratp_an_expected(ri, hdr))
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
/*
* This state represents the final behavior of the CLOSING state.
*
* If the AN field value was expected then this packet
* acknowledges the FIN packet recently sent. This is the final
* acknowledging message indicating both side's agreement to close
* the connection. Start the 2*SRTT timer associated with the
* TIME-WAIT state, discard the packet, and go to the TIME-WAIT
* state without any further processing.
*
* Otherwise the AN field value was unexpected. Discard the
* packet and remain in the current state without any further
* processing.
*/
static int ratp_behaviour_h5(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
pr_debug("%s\n", __func__);
if (ratp_an_expected(ri, hdr)) {
ratp_state_change(ri, RATP_STATE_TIME_WAIT);
ratp_start_time_wait_timer(ri);
}
return 0;
}
/*
* This state represents the behavior of the TIME-WAIT state.
* Check the presence of the ACK flag. If ACK is not set then
* discard the packet and return without any further processing.
*
* Check the presence of the FIN flag. If FIN is not set then
* discard the packet and return without any further processing.
*
* We now assume that the FIN flag was set. This situation
* indicates that the last acknowledgment of the FIN packet sent
* by the other end of the connection did not arrive. Resend the
* acknowledgment:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
*
* Restart the 2*SRTT timer, discard the packet, and remain in the
* current state without any further processing.
*/
static int ratp_behaviour_h6(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
uint8_t control;
pr_debug("%s\n", __func__);
if (!(hdr->control & RATP_CONTROL_ACK))
return 1;
if (!(hdr->control & RATP_CONTROL_FIN))
return 1;
control = ratp_set_next_sn(ratp_an(hdr)) | RATP_CONTROL_ACK;
ratp_send_hdr(ri, control);
ratp_start_time_wait_timer(ri);
return 0;
}
static int msg_recv(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
struct ratp_message *msg;
pr_debug("%s: Put msg in receive queue\n", __func__);
msg = xzalloc(sizeof(*msg));
if (hdr->data_length) {
msg->len = hdr->data_length;
msg->buf = xzalloc(msg->len);
memcpy(msg->buf, pkt + sizeof(struct ratp_header), msg->len);
} else {
msg->len = 1;
msg->buf = xzalloc(1);
*(uint8_t *)msg->buf = hdr->data_length;
}
if (hdr->control & RATP_CONTROL_EOR)
msg->eor = 1;
list_add_tail(&msg->list, &ri->recvmsg);
return 0;
}
/*
* This represents that stage of processing in the ESTABLISHED
* state in which all the flag bits have been processed and only
* data may remain. The packet is examined to see if it contains
* data. If not the packet is now discarded, return to the
* current state without any further processing.
*
* We assume the packet contained data, that either the SO flag
* was set or LENGTH is positive. That data is placed into the
* user's receive buffers. As these become full the user should
* be informed "Receive buffer full." An acknowledgment is sent:
*
* <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
*
* If data is queued to send then it is most efficient to
* 'piggyback' this acknowledgment on that data packet.
*
* The packet is now discarded, return to the ESTABLISHED state
* without any further processing.
*/
static int ratp_behaviour_i1(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
if (!ratp_has_data (hdr))
return 1;
pr_vdebug("%s **received** %d\n", __func__, hdr->data_length);
ri->sn_received = ratp_sn(hdr);
msg_recv(ri, pkt);
if (list_empty(&ri->sendmsg) || ri->sendmsg_current)
ratp_send_ack(ri, hdr);
else
ratp_send_next_data(ri);
return 0;
}
/*
* State machine as desribed in RFC916
*
* STATE BEHAVIOR
* =============+========================
* LISTEN | A
* -------------+------------------------
* SYN-SENT | B
* -------------+------------------------
* SYN-RECEIVED | C1 D1 E F1 H1
* -------------+------------------------
* ESTABLISHED | C2 D2 E F2 H2 I1
* -------------+------------------------
* FIN-WAIT | C2 D2 E F3 H3
* -------------+------------------------
* LAST-ACK | C2 D3 E F3 H4
* -------------+------------------------
* CLOSING | C2 D3 E F3 H5
* -------------+------------------------
* TIME-WAIT | D3 E F3 H6
* -------------+------------------------
* CLOSED | G
* -------------+------------------------
*/
static int ratp_state_machine(struct ratp_internal *ri, void *pkt)
{
struct ratp_header *hdr = pkt;
int ret;
ratp_print_header(ri, hdr, " recv");
pr_debug(" state %s\n", ratp_state_str[ri->state]);
switch (ri->state) {
case RATP_STATE_LISTEN:
ratp_behaviour_a(ri, pkt);
break;
case RATP_STATE_SYN_SENT:
ratp_behaviour_b(ri, pkt);
break;
case RATP_STATE_SYN_RECEIVED:
ret = ratp_behaviour_c1(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_d1(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_e(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_f1(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_h1(ri, pkt);
if (ret)
return ret;
break;
case RATP_STATE_ESTABLISHED:
ret = ratp_behaviour_c2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_d2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_e(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_f2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_h2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_i1(ri, pkt);
if (ret)
return ret;
break;
case RATP_STATE_FIN_WAIT:
ret = ratp_behaviour_c2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_d2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_e(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_f3(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_h3(ri, pkt);
if (ret)
return ret;
break;
case RATP_STATE_LAST_ACK:
ret = ratp_behaviour_c2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_d3(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_e(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_f3(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_h4(ri, pkt);
if (ret)
return ret;
break;
case RATP_STATE_CLOSING:
ret = ratp_behaviour_c2(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_d3(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_e(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_f3(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_h5(ri, pkt);
if (ret)
return ret;
break;
case RATP_STATE_TIME_WAIT:
ret = ratp_behaviour_d3(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_e(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_f3(ri, pkt);
if (ret)
return ret;
ret = ratp_behaviour_h6(ri, pkt);
if (ret)
return ret;
break;
case RATP_STATE_CLOSED:
ratp_behaviour_g(ri, pkt);
break;
};
return 0;
}
/**
* ratp_closed() - Check if a connection is closed
*
* Return: true if a connection is closed, false otherwise
*/
bool ratp_closed(struct ratp *ratp)
{
struct ratp_internal *ri = ratp->internal;
if (!ri)
return true;
return ri->state == RATP_STATE_CLOSED;
}
/**
* ratp_busy() - Check if we are inside the RATP code
*
* Needed for RATP debugging. The RATP console uses this to determine
* if it is called from inside the RATP code.
*
* Return: true if we are inside the RATP code, false otherwise
*/
bool ratp_busy(struct ratp *ratp)
{
struct ratp_internal *ri = ratp->internal;
if (!ri)
return false;
return ri->in_ratp != 0;
}
/**
* ratp_poll() - Execute RATP state machine
* @ratp: The RATP link
*
* This function should be executed periodically to keep the RATP state
* machine going.
*
* Return: 0 if successful, a negative error code otherwise.
*/
int ratp_poll(struct ratp *ratp)
{
struct ratp_internal *ri = ratp->internal;
int ret;
if (!ri)
return -ENETDOWN;
ri->in_ratp++;
ret = ratp_recv_pkt(ri, ri->recvbuf, 100);
if (ret == 0) {
if (ri->state == RATP_STATE_TIME_WAIT &&
is_timeout(ri->timewait_timer_start, ri->srtt * 2 * MSECOND)) {
pr_debug("2*SRTT timer timed out\n");
ret = -ECONNRESET;
goto out;
}
ret = ratp_state_machine(ri, ri->recvbuf);
if (ret < 0)
goto out;
if (ri->status < 0) {
ret = ri->status;
goto out;
}
}
if (ri->sendmsg_current && is_timeout(ri->retransmission_timer_start,
ri->rto * MSECOND)) {
ri->retransmission_count++;
if (ri->retransmission_count == ri->max_retransmission) {
ri->status = ret = -ETIMEDOUT;
ri->state = RATP_STATE_CLOSED;
goto out;
}
pr_debug("%s: retransmit\n", __func__);
ratp_print_header(ri, ri->sendbuf, "resend");
ri->retransmission_timer_start = get_time_ns();
ret = ri->ratp->send(ratp, ri->sendbuf, ri->sendbuf_len);
if (ret)
goto out;
}
if (!ri->sendmsg_current && !list_empty(&ri->sendmsg))
ratp_send_next_data(ri);
ret = 0;
out:
ri->in_ratp--;
return ret;
}
/**
* ratp_establish(): Establish a RATP link
* @ratp: The RATP link
* @active: if true actively create a connection
* @timeout_ms: Timeout in ms to wait until a connection is established. If
* 0 wait forever.
*
* This function establishes a link with the remote end. It expects the
* send and receive functions to be set, all other struct ratp_internal members can
* be left uninitialized.
*
* Return: 0 if successful, a negative error code otherwise.
*/
int ratp_establish(struct ratp *ratp, bool active, int timeout_ms)
{
struct ratp_internal *ri;
int ret;
uint64_t start;
ri = xzalloc(sizeof(*ri));
ri->ratp = ratp;
ratp->internal = ri;
ri->recvbuf = xmalloc(512);
ri->sendbuf = xmalloc(512);
INIT_LIST_HEAD(&ri->recvmsg);
INIT_LIST_HEAD(&ri->sendmsg);
ri->max_retransmission = 100;
ri->srtt = 100;
ri->rto = 100;
ri->active = active;
ri->in_ratp++;
if (ri->active) {
ratp_send_hdr(ri, RATP_CONTROL_SYN);
ratp_state_change(ri, RATP_STATE_SYN_SENT);
}
start = get_time_ns();
while (1) {
ret = ratp_poll(ri->ratp);
if (ret < 0)
goto out;
if (ri->state == RATP_STATE_ESTABLISHED) {
ret = 0;
goto out;
}
if (timeout_ms && is_timeout(start, MSECOND * timeout_ms)) {
ret = -ETIMEDOUT;
goto out;
}
}
out:
ri->in_ratp--;
if (ret) {
free(ri->recvbuf);
free(ri->sendbuf);
free(ri);
ratp->internal = NULL;
}
return ret;
}
void ratp_close(struct ratp *ratp)
{
struct ratp_internal *ri = ratp->internal;
struct ratp_message *msg, *tmp;
struct ratp_header fin = {};
if (!ri)
return;
if (ri->state == RATP_STATE_ESTABLISHED || ri->state == RATP_STATE_SYN_RECEIVED) {
uint64_t start;
u8 control;
pr_debug("Closing...\n");
ratp_state_change(ri, RATP_STATE_FIN_WAIT);
control = ratp_set_next_sn(ri->sn_sent) |
ratp_set_next_an(ri->sn_received) |
RATP_CONTROL_FIN | RATP_CONTROL_ACK;
ratp_create_packet(ri, &fin, control, 0);
ratp_send_pkt(ri, &fin, sizeof(fin));
start = get_time_ns();
while (!is_timeout(start, ri->srtt * MSECOND * 2))
ratp_poll(ratp);
}
list_for_each_entry_safe(msg, tmp, &ri->sendmsg, list)
ratp_msg_done(ri, msg, -ECONNRESET);
free(ri->recvbuf);
free(ri->sendbuf);
free(ri);
ratp->internal = NULL;
pr_debug("Closed\n");
}
/**
* ratp_send_complete(): Send data over a RATP link
* @ratp: The RATP link
* @data: The data buffer
* @len: The length of the message to send
* @complete: The completion callback for the message
* @complete_ctx: context pointer for the completion callback
*
* Queue a RATP message for transmission. This only queues the message,
* ratp_poll has to be called to actually transfer the message.
* @complete will be called upon completion of the message.
*
* Return: 0 if successful, a negative error code otherwise.
*/
int ratp_send_complete(struct ratp *ratp, const uint8_t *data, size_t len,
void (*complete)(void *ctx, int status), void *complete_ctx)
{
struct ratp_internal *ri = ratp->internal;
struct ratp_message *msg;
int sent = 0;
if (!ri || ri->state != RATP_STATE_ESTABLISHED)
return -ENETDOWN;
if (!len)
return -EINVAL;
ri->in_ratp++;
while (len) {
int now = min((int)len, 255);
msg = xzalloc(sizeof(*msg));
msg->buf = xzalloc(sizeof(struct ratp_header) + now + 2);
msg->len = now;
memcpy(msg->buf + sizeof(struct ratp_header), data + sent, now);
list_add_tail(&msg->list, &ri->sendmsg);
len -= now;
sent += now;
}
msg->eor = 1;
msg->complete = complete;
msg->complete_ctx = complete_ctx;
ri->in_ratp--;
return 0;
}
/**
* ratp_send(): Send data over a RATP link
* @ratp: The RATP link
* @data: The data buffer
* @len: The length of the message to send
*
* Queue a RATP message for transmission. This only queues the message,
* ratp_poll has to be called to actually transfer the message.
*
* Return: 0 if successful, a negative error code otherwise.
*/
int ratp_send(struct ratp *ratp, const void *data, size_t len)
{
return ratp_send_complete(ratp, data, len, NULL, NULL);
}
/**
* ratp_recv() - Receive data from a RATP link
* @ratp: The RATP link
* @data: Pointer to data
* @len: The length of the data in bytes
*
* If a message is available it fills @data with a pointer to the data.
* This function does not wait for new messages. If no data is available
* -EAGAIN is returned. If data is received @data has to be freed by the
* caller.
*
* Return: 0 if successful, a negative error code otherwise.
*/
int ratp_recv(struct ratp *ratp, void **data, size_t *len)
{
struct ratp_internal *ri = ratp->internal;
struct ratp_message *msg, *tmp;
void *pos;
int num = 0;
*len = 0;
if (!ri || ri->state != RATP_STATE_ESTABLISHED)
return -ENETDOWN;
if (list_empty(&ri->recvmsg))
return -EAGAIN;
list_for_each_entry(msg, &ri->recvmsg, list) {
*len += msg->len;
num++;
if (msg->eor)
goto eor;
}
return -EAGAIN;
eor:
*data = malloc(*len);
if (!*data)
return -ENOMEM;
pos = *data;
list_for_each_entry_safe(msg, tmp, &ri->recvmsg, list) {
memcpy(pos, msg->buf, msg->len);
pos += msg->len;
list_del(&msg->list);
free(msg->buf);
free(msg);
}
return 0;
}
