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asterisk/main/udptl.c
Russell Bryant cc0b7e7df5 Some scheduler API cleanup and improvements. 
Previously, I had added the ast_sched_thread stuff that was a generic scheduler
thread implementation.  However, if you used it, it required using different
functions for modifying scheduler contents.  This patch reworks how this is
done and just allows you to optionally start a thread on the original scheduler
context structure that has always been there.  This makes it trivial to switch
to the generic scheduler thread implementation without having to touch any of
the other code that adds or removes scheduler entries.

In passing, I made some naming tweaks to add ast_ prefixes where they were not
there before.

Review: https://reviewboard.asterisk.org/r/1007/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@299091 65c4cc65-6c06-0410-ace0-fbb531ad65f3
2010-12-20 17:15:54 +00:00

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/*
* Asterisk -- A telephony toolkit for Linux.
*
* UDPTL support for T.38
*
* Copyright (C) 2005, Steve Underwood, partly based on RTP code which is
* Copyright (C) 1999-2009, Digium, Inc.
*
* Steve Underwood <steveu@coppice.org>
* Kevin P. Fleming <kpfleming@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*
* A license has been granted to Digium (via disclaimer) for the use of
* this code.
*/
/*!
* \file
*
* \brief UDPTL support for T.38 faxing
*
*
* \author Mark Spencer <markster@digium.com>
* \author Steve Underwood <steveu@coppice.org>
* \author Kevin P. Fleming <kpfleming@digium.com>
*
* \page T38fax_udptl T.38 support :: UDPTL
*
* Asterisk supports T.38 fax passthrough, origination and termination. It does
* not support gateway operation. The only channel driver that supports T.38 at
* this time is chan_sip.
*
* UDPTL is handled very much like RTP. It can be reinvited to go directly between
* the endpoints, without involving Asterisk in the media stream.
*
* \b References:
* - chan_sip.c
* - udptl.c
* - app_fax.c
*/
#include "asterisk.h"
ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include <sys/time.h>
#include <signal.h>
#include <fcntl.h>
#include "asterisk/udptl.h"
#include "asterisk/frame.h"
#include "asterisk/channel.h"
#include "asterisk/acl.h"
#include "asterisk/config.h"
#include "asterisk/lock.h"
#include "asterisk/utils.h"
#include "asterisk/netsock.h"
#include "asterisk/cli.h"
#include "asterisk/unaligned.h"
#define UDPTL_MTU 1200
#if !defined(FALSE)
#define FALSE 0
#endif
#if !defined(TRUE)
#define TRUE (!FALSE)
#endif
#define LOG_TAG(u) S_OR(u->tag, "no tag")
static int udptlstart = 4500;
static int udptlend = 4599;
static int udptldebug; /*!< Are we debugging? */
static struct ast_sockaddr udptldebugaddr; /*!< Debug packets to/from this host */
#ifdef SO_NO_CHECK
static int nochecksums;
#endif
static int udptlfecentries;
static int udptlfecspan;
static int use_even_ports;
#define LOCAL_FAX_MAX_DATAGRAM 1400
#define DEFAULT_FAX_MAX_DATAGRAM 400
#define FAX_MAX_DATAGRAM_LIMIT 1400
#define MAX_FEC_ENTRIES 5
#define MAX_FEC_SPAN 5
#define UDPTL_BUF_MASK 15
typedef struct {
int buf_len;
uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
} udptl_fec_tx_buffer_t;
typedef struct {
int buf_len;
uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
unsigned int fec_len[MAX_FEC_ENTRIES];
uint8_t fec[MAX_FEC_ENTRIES][LOCAL_FAX_MAX_DATAGRAM];
unsigned int fec_span;
unsigned int fec_entries;
} udptl_fec_rx_buffer_t;
/*! \brief Structure for an UDPTL session */
struct ast_udptl {
int fd;
char resp;
struct ast_frame f[16];
unsigned char rawdata[8192 + AST_FRIENDLY_OFFSET];
unsigned int lasteventseqn;
int nat;
int flags;
struct ast_sockaddr us;
struct ast_sockaddr them;
int *ioid;
struct ast_sched_context *sched;
struct io_context *io;
void *data;
char *tag;
ast_udptl_callback callback;
/*! This option indicates the error correction scheme used in transmitted UDPTL
* packets and expected in received UDPTL packets.
*/
enum ast_t38_ec_modes error_correction_scheme;
/*! This option indicates the number of error correction entries transmitted in
* UDPTL packets and expected in received UDPTL packets.
*/
unsigned int error_correction_entries;
/*! This option indicates the span of the error correction entries in transmitted
* UDPTL packets (FEC only).
*/
unsigned int error_correction_span;
/*! The maximum size UDPTL packet that can be accepted by
* the remote device.
*/
int far_max_datagram;
/*! The maximum size UDPTL packet that we are prepared to
* accept, or -1 if it hasn't been calculated since the last
* changes were applied to the UDPTL structure.
*/
int local_max_datagram;
/*! The maximum IFP that can be submitted for sending
* to the remote device. Calculated from far_max_datagram,
* error_correction_scheme and error_correction_entries,
* or -1 if it hasn't been calculated since the last
* changes were applied to the UDPTL structure.
*/
int far_max_ifp;
/*! The maximum IFP that the local endpoint is prepared
* to accept. Along with error_correction_scheme and
* error_correction_entries, used to calculate local_max_datagram.
*/
int local_max_ifp;
int verbose;
unsigned int tx_seq_no;
unsigned int rx_seq_no;
unsigned int rx_expected_seq_no;
udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1];
udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1];
};
static AST_RWLIST_HEAD_STATIC(protos, ast_udptl_protocol);
static inline int udptl_debug_test_addr(const struct ast_sockaddr *addr)
{
if (udptldebug == 0)
return 0;
if (ast_sockaddr_isnull(&udptldebugaddr)) {
return 1;
}
if (ast_sockaddr_port(&udptldebugaddr)) {
return !ast_sockaddr_cmp(&udptldebugaddr, addr);
} else {
return !ast_sockaddr_cmp_addr(&udptldebugaddr, addr);
}
}
static int decode_length(uint8_t *buf, unsigned int limit, unsigned int *len, unsigned int *pvalue)
{
if (*len >= limit)
return -1;
if ((buf[*len] & 0x80) == 0) {
*pvalue = buf[*len];
(*len)++;
return 0;
}
if ((buf[*len] & 0x40) == 0) {
if (*len == limit - 1)
return -1;
*pvalue = (buf[*len] & 0x3F) << 8;
(*len)++;
*pvalue |= buf[*len];
(*len)++;
return 0;
}
*pvalue = (buf[*len] & 0x3F) << 14;
(*len)++;
/* Indicate we have a fragment */
return 1;
}
/*- End of function --------------------------------------------------------*/
static int decode_open_type(uint8_t *buf, unsigned int limit, unsigned int *len, const uint8_t **p_object, unsigned int *p_num_octets)
{
unsigned int octet_cnt;
unsigned int octet_idx;
unsigned int i;
int length; /* a negative length indicates the limit has been reached in decode_length. */
const uint8_t **pbuf;
for (octet_idx = 0, *p_num_octets = 0; ; octet_idx += octet_cnt) {
octet_cnt = 0;
if ((length = decode_length(buf, limit, len, &octet_cnt)) < 0)
return -1;
if (octet_cnt > 0) {
*p_num_octets += octet_cnt;
pbuf = &p_object[octet_idx];
i = 0;
/* Make sure the buffer contains at least the number of bits requested */
if ((*len + octet_cnt) > limit)
return -1;
*pbuf = &buf[*len];
*len += octet_cnt;
}
if (length == 0)
break;
}
return 0;
}
/*- End of function --------------------------------------------------------*/
static unsigned int encode_length(uint8_t *buf, unsigned int *len, unsigned int value)
{
unsigned int multiplier;
if (value < 0x80) {
/* 1 octet */
buf[*len] = value;
(*len)++;
return value;
}
if (value < 0x4000) {
/* 2 octets */
/* Set the first bit of the first octet */
buf[*len] = ((0x8000 | value) >> 8) & 0xFF;
(*len)++;
buf[*len] = value & 0xFF;
(*len)++;
return value;
}
/* Fragmentation */
multiplier = (value < 0x10000) ? (value >> 14) : 4;
/* Set the first 2 bits of the octet */
buf[*len] = 0xC0 | multiplier;
(*len)++;
return multiplier << 14;
}
/*- End of function --------------------------------------------------------*/
static int encode_open_type(const struct ast_udptl *udptl, uint8_t *buf, unsigned int buflen,
unsigned int *len, const uint8_t *data, unsigned int num_octets)
{
unsigned int enclen;
unsigned int octet_idx;
uint8_t zero_byte;
/* If open type is of zero length, add a single zero byte (10.1) */
if (num_octets == 0) {
zero_byte = 0;
data = &zero_byte;
num_octets = 1;
}
/* Encode the open type */
for (octet_idx = 0; ; num_octets -= enclen, octet_idx += enclen) {
if ((enclen = encode_length(buf, len, num_octets)) < 0)
return -1;
if (enclen + *len > buflen) {
ast_log(LOG_ERROR, "(%s): Buffer overflow detected (%d + %d > %d)\n",
LOG_TAG(udptl), enclen, *len, buflen);
return -1;
}
if (enclen > 0) {
memcpy(&buf[*len], &data[octet_idx], enclen);
*len += enclen;
}
if (enclen >= num_octets)
break;
}
return 0;
}
/*- End of function --------------------------------------------------------*/
static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, unsigned int len)
{
int stat1;
int stat2;
int i;
int j;
int k;
int l;
int m;
int x;
int limit;
int which;
unsigned int ptr;
unsigned int count;
int total_count;
int seq_no;
const uint8_t *ifp;
const uint8_t *data;
unsigned int ifp_len;
int repaired[16];
const uint8_t *bufs[16];
unsigned int lengths[16];
int span;
int entries;
int ifp_no;
ptr = 0;
ifp_no = 0;
memset(&s->f[0], 0, sizeof(s->f[0]));
/* Decode seq_number */
if (ptr + 2 > len)
return -1;
seq_no = (buf[0] << 8) | buf[1];
ptr += 2;
/* Break out the primary packet */
if ((stat1 = decode_open_type(buf, len, &ptr, &ifp, &ifp_len)) != 0)
return -1;
/* Decode error_recovery */
if (ptr + 1 > len)
return -1;
if ((buf[ptr++] & 0x80) == 0) {
/* Secondary packet mode for error recovery */
if (seq_no > s->rx_seq_no) {
/* We received a later packet than we expected, so we need to check if we can fill in the gap from the
secondary packets. */
total_count = 0;
do {
if ((stat2 = decode_length(buf, len, &ptr, &count)) < 0)
return -1;
for (i = 0; i < count; i++) {
if ((stat1 = decode_open_type(buf, len, &ptr, &bufs[total_count + i], &lengths[total_count + i])) != 0)
return -1;
}
total_count += count;
}
while (stat2 > 0);
/* Step through in reverse order, so we go oldest to newest */
for (i = total_count; i > 0; i--) {
if (seq_no - i >= s->rx_seq_no) {
/* This one wasn't seen before */
/* Decode the secondary IFP packet */
//fprintf(stderr, "Secondary %d, len %d\n", seq_no - i, lengths[i - 1]);
s->f[ifp_no].frametype = AST_FRAME_MODEM;
s->f[ifp_no].subclass.codec = AST_MODEM_T38;
s->f[ifp_no].mallocd = 0;
s->f[ifp_no].seqno = seq_no - i;
s->f[ifp_no].datalen = lengths[i - 1];
s->f[ifp_no].data.ptr = (uint8_t *) bufs[i - 1];
s->f[ifp_no].offset = 0;
s->f[ifp_no].src = "UDPTL";
if (ifp_no > 0)
AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
ifp_no++;
}
}
}
}
else
{
/* FEC mode for error recovery */
/* Our buffers cannot tolerate overlength IFP packets in FEC mode */
if (ifp_len > LOCAL_FAX_MAX_DATAGRAM)
return -1;
/* Update any missed slots in the buffer */
for ( ; seq_no > s->rx_seq_no; s->rx_seq_no++) {
x = s->rx_seq_no & UDPTL_BUF_MASK;
s->rx[x].buf_len = -1;
s->rx[x].fec_len[0] = 0;
s->rx[x].fec_span = 0;
s->rx[x].fec_entries = 0;
}
x = seq_no & UDPTL_BUF_MASK;
memset(repaired, 0, sizeof(repaired));
/* Save the new IFP packet */
memcpy(s->rx[x].buf, ifp, ifp_len);
s->rx[x].buf_len = ifp_len;
repaired[x] = TRUE;
/* Decode the FEC packets */
/* The span is defined as an unconstrained integer, but will never be more
than a small value. */
if (ptr + 2 > len)
return -1;
if (buf[ptr++] != 1)
return -1;
span = buf[ptr++];
s->rx[x].fec_span = span;
/* The number of entries is defined as a length, but will only ever be a small
value. Treat it as such. */
if (ptr + 1 > len)
return -1;
entries = buf[ptr++];
s->rx[x].fec_entries = entries;
/* Decode the elements */
for (i = 0; i < entries; i++) {
if ((stat1 = decode_open_type(buf, len, &ptr, &data, &s->rx[x].fec_len[i])) != 0)
return -1;
if (s->rx[x].fec_len[i] > LOCAL_FAX_MAX_DATAGRAM)
return -1;
/* Save the new FEC data */
memcpy(s->rx[x].fec[i], data, s->rx[x].fec_len[i]);
#if 0
fprintf(stderr, "FEC: ");
for (j = 0; j < s->rx[x].fec_len[i]; j++)
fprintf(stderr, "%02X ", data[j]);
fprintf(stderr, "\n");
#endif
}
/* See if we can reconstruct anything which is missing */
/* TODO: this does not comprehensively hunt back and repair everything that is possible */
for (l = x; l != ((x - (16 - span*entries)) & UDPTL_BUF_MASK); l = (l - 1) & UDPTL_BUF_MASK) {
if (s->rx[l].fec_len[0] <= 0)
continue;
for (m = 0; m < s->rx[l].fec_entries; m++) {
limit = (l + m) & UDPTL_BUF_MASK;
for (which = -1, k = (limit - s->rx[l].fec_span * s->rx[l].fec_entries) & UDPTL_BUF_MASK; k != limit; k = (k + s->rx[l].fec_entries) & UDPTL_BUF_MASK) {
if (s->rx[k].buf_len <= 0)
which = (which == -1) ? k : -2;
}
if (which >= 0) {
/* Repairable */
for (j = 0; j < s->rx[l].fec_len[m]; j++) {
s->rx[which].buf[j] = s->rx[l].fec[m][j];
for (k = (limit - s->rx[l].fec_span * s->rx[l].fec_entries) & UDPTL_BUF_MASK; k != limit; k = (k + s->rx[l].fec_entries) & UDPTL_BUF_MASK)
s->rx[which].buf[j] ^= (s->rx[k].buf_len > j) ? s->rx[k].buf[j] : 0;
}
s->rx[which].buf_len = s->rx[l].fec_len[m];
repaired[which] = TRUE;
}
}
}
/* Now play any new packets forwards in time */
for (l = (x + 1) & UDPTL_BUF_MASK, j = seq_no - UDPTL_BUF_MASK; l != x; l = (l + 1) & UDPTL_BUF_MASK, j++) {
if (repaired[l]) {
//fprintf(stderr, "Fixed packet %d, len %d\n", j, l);
s->f[ifp_no].frametype = AST_FRAME_MODEM;
s->f[ifp_no].subclass.codec = AST_MODEM_T38;
s->f[ifp_no].mallocd = 0;
s->f[ifp_no].seqno = j;
s->f[ifp_no].datalen = s->rx[l].buf_len;
s->f[ifp_no].data.ptr = s->rx[l].buf;
s->f[ifp_no].offset = 0;
s->f[ifp_no].src = "UDPTL";
if (ifp_no > 0)
AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
ifp_no++;
}
}
}
/* If packets are received out of sequence, we may have already processed this packet from the error
recovery information in a packet already received. */
if (seq_no >= s->rx_seq_no) {
/* Decode the primary IFP packet */
s->f[ifp_no].frametype = AST_FRAME_MODEM;
s->f[ifp_no].subclass.codec = AST_MODEM_T38;
s->f[ifp_no].mallocd = 0;
s->f[ifp_no].seqno = seq_no;
s->f[ifp_no].datalen = ifp_len;
s->f[ifp_no].data.ptr = (uint8_t *) ifp;
s->f[ifp_no].offset = 0;
s->f[ifp_no].src = "UDPTL";
if (ifp_no > 0)
AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
ifp_no++;
}
s->rx_seq_no = seq_no + 1;
return ifp_no;
}
/*- End of function --------------------------------------------------------*/
static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, unsigned int buflen, uint8_t *ifp, unsigned int ifp_len)
{
uint8_t fec[LOCAL_FAX_MAX_DATAGRAM * 2];
int i;
int j;
int seq;
int entry;
int entries;
int span;
int m;
unsigned int len;
int limit;
int high_tide;
seq = s->tx_seq_no & 0xFFFF;
/* Map the sequence number to an entry in the circular buffer */
entry = seq & UDPTL_BUF_MASK;
/* We save the message in a circular buffer, for generating FEC or
redundancy sets later on. */
s->tx[entry].buf_len = ifp_len;
memcpy(s->tx[entry].buf, ifp, ifp_len);
/* Build the UDPTLPacket */
len = 0;
/* Encode the sequence number */
buf[len++] = (seq >> 8) & 0xFF;
buf[len++] = seq & 0xFF;
/* Encode the primary IFP packet */
if (encode_open_type(s, buf, buflen, &len, ifp, ifp_len) < 0)
return -1;
/* Encode the appropriate type of error recovery information */
switch (s->error_correction_scheme)
{
case UDPTL_ERROR_CORRECTION_NONE:
/* Encode the error recovery type */
buf[len++] = 0x00;
/* The number of entries will always be zero, so it is pointless allowing
for the fragmented case here. */
if (encode_length(buf, &len, 0) < 0)
return -1;
break;
case UDPTL_ERROR_CORRECTION_REDUNDANCY:
/* Encode the error recovery type */
buf[len++] = 0x00;
if (s->tx_seq_no > s->error_correction_entries)
entries = s->error_correction_entries;
else
entries = s->tx_seq_no;
/* The number of entries will always be small, so it is pointless allowing
for the fragmented case here. */
if (encode_length(buf, &len, entries) < 0)
return -1;
/* Encode the elements */
for (i = 0; i < entries; i++) {
j = (entry - i - 1) & UDPTL_BUF_MASK;
if (encode_open_type(s, buf, buflen, &len, s->tx[j].buf, s->tx[j].buf_len) < 0) {
ast_debug(1, "(%s): Encoding failed at i=%d, j=%d\n",
LOG_TAG(s), i, j);
return -1;
}
}
break;
case UDPTL_ERROR_CORRECTION_FEC:
span = s->error_correction_span;
entries = s->error_correction_entries;
if (seq < s->error_correction_span*s->error_correction_entries) {
/* In the initial stages, wind up the FEC smoothly */
entries = seq/s->error_correction_span;
if (seq < s->error_correction_span)
span = 0;
}
/* Encode the error recovery type */
buf[len++] = 0x80;
/* Span is defined as an inconstrained integer, which it dumb. It will only
ever be a small value. Treat it as such. */
buf[len++] = 1;
buf[len++] = span;
/* The number of entries is defined as a length, but will only ever be a small
value. Treat it as such. */
buf[len++] = entries;
for (m = 0; m < entries; m++) {
/* Make an XOR'ed entry the maximum length */
limit = (entry + m) & UDPTL_BUF_MASK;
high_tide = 0;
for (i = (limit - span*entries) & UDPTL_BUF_MASK; i != limit; i = (i + entries) & UDPTL_BUF_MASK) {
if (high_tide < s->tx[i].buf_len) {
for (j = 0; j < high_tide; j++)
fec[j] ^= s->tx[i].buf[j];
for ( ; j < s->tx[i].buf_len; j++)
fec[j] = s->tx[i].buf[j];
high_tide = s->tx[i].buf_len;
} else {
for (j = 0; j < s->tx[i].buf_len; j++)
fec[j] ^= s->tx[i].buf[j];
}
}
if (encode_open_type(s, buf, buflen, &len, fec, high_tide) < 0)
return -1;
}
break;
}
if (s->verbose)
fprintf(stderr, "\n");
s->tx_seq_no++;
return len;
}
int ast_udptl_fd(const struct ast_udptl *udptl)
{
return udptl->fd;
}
void ast_udptl_set_data(struct ast_udptl *udptl, void *data)
{
udptl->data = data;
}
void ast_udptl_set_callback(struct ast_udptl *udptl, ast_udptl_callback callback)
{
udptl->callback = callback;
}
void ast_udptl_setnat(struct ast_udptl *udptl, int nat)
{
udptl->nat = nat;
}
static int udptlread(int *id, int fd, short events, void *cbdata)
{
struct ast_udptl *udptl = cbdata;
struct ast_frame *f;
if ((f = ast_udptl_read(udptl))) {
if (udptl->callback)
udptl->callback(udptl, f, udptl->data);
}
return 1;
}
struct ast_frame *ast_udptl_read(struct ast_udptl *udptl)
{
int res;
struct ast_sockaddr addr;
uint16_t seqno = 0;
uint16_t *udptlheader;
/* Cache where the header will go */
res = ast_recvfrom(udptl->fd,
udptl->rawdata + AST_FRIENDLY_OFFSET,
sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET,
0,
&addr);
udptlheader = (uint16_t *)(udptl->rawdata + AST_FRIENDLY_OFFSET);
if (res < 0) {
if (errno != EAGAIN)
ast_log(LOG_WARNING, "(%s): UDPTL read error: %s\n",
LOG_TAG(udptl), strerror(errno));
ast_assert(errno != EBADF);
return &ast_null_frame;
}
/* Ignore if the other side hasn't been given an address yet. */
if (ast_sockaddr_isnull(&udptl->them)) {
return &ast_null_frame;
}
if (udptl->nat) {
/* Send to whoever sent to us */
if (ast_sockaddr_cmp(&udptl->them, &addr)) {
ast_sockaddr_copy(&udptl->them, &addr);
ast_debug(1, "UDPTL NAT (%s): Using address %s\n",
LOG_TAG(udptl), ast_sockaddr_stringify(&udptl->them));
}
}
if (udptl_debug_test_addr(&addr)) {
ast_verb(1, "UDPTL (%s): packet from %s (type %d, seq %d, len %d)\n",
LOG_TAG(udptl), ast_sockaddr_stringify(&addr), 0, seqno, res);
}
if (udptl_rx_packet(udptl, udptl->rawdata + AST_FRIENDLY_OFFSET, res) < 1)
return &ast_null_frame;
return &udptl->f[0];
}
static void calculate_local_max_datagram(struct ast_udptl *udptl)
{
unsigned int new_max = 0;
if (udptl->local_max_ifp == -1) {
ast_log(LOG_WARNING, "(%s): Cannot calculate local_max_datagram before local_max_ifp has been set.\n",
LOG_TAG(udptl));
udptl->local_max_datagram = -1;
return;
}
/* calculate the amount of space required to receive an IFP
* of the maximum size supported by the application/endpoint
* that we are delivering them to (local endpoint), and add
* the amount of space required to support the selected
* error correction mode
*/
switch (udptl->error_correction_scheme) {
case UDPTL_ERROR_CORRECTION_NONE:
/* need room for sequence number, length indicator, redundancy
* indicator and following length indicator
*/
new_max = 5 + udptl->local_max_ifp;
break;
case UDPTL_ERROR_CORRECTION_REDUNDANCY:
/* need room for sequence number, length indicators, plus
* room for up to 3 redundancy packets
*/
new_max = 5 + udptl->local_max_ifp + 2 + (3 * udptl->local_max_ifp);
break;
case UDPTL_ERROR_CORRECTION_FEC:
/* need room for sequence number, length indicators and a
* a single IFP of the maximum size expected
*/
new_max = 5 + udptl->local_max_ifp + 4 + udptl->local_max_ifp;
break;
}
/* add 5% extra space for insurance, but no larger than LOCAL_FAX_MAX_DATAGRAM */
udptl->local_max_datagram = MIN(new_max * 1.05, LOCAL_FAX_MAX_DATAGRAM);
}
static void calculate_far_max_ifp(struct ast_udptl *udptl)
{
unsigned new_max = 0;
if (udptl->far_max_datagram == -1) {
ast_log(LOG_WARNING, "(%s): Cannot calculate far_max_ifp before far_max_datagram has been set.\n",
LOG_TAG(udptl));
udptl->far_max_ifp = -1;
return;
}
/* the goal here is to supply the local endpoint (application
* or bridged channel) a maximum IFP value that will allow it
* to effectively and efficiently transfer image data at its
* selected bit rate, taking into account the selected error
* correction mode, but without overrunning the far endpoint's
* datagram buffer. this is complicated by the fact that some
* far endpoints send us bogus (small) max datagram values,
* which would result in either buffer overrun or no error
* correction. we try to accomodate those, but if the supplied
* value is too small to do so, we'll emit warning messages and
* the user will have to use configuration options to override
* the max datagram value supplied by the far endpoint.
*/
switch (udptl->error_correction_scheme) {
case UDPTL_ERROR_CORRECTION_NONE:
/* need room for sequence number, length indicator, redundancy
* indicator and following length indicator
*/
new_max = udptl->far_max_datagram - 5;
break;
case UDPTL_ERROR_CORRECTION_REDUNDANCY:
/* for this case, we'd like to send as many error correction entries
* as possible (up to the number we're configured for), but we'll settle
* for sending fewer if the configured number would cause the
* calculated max IFP to be too small for effective operation
*
* need room for sequence number, length indicators and the
* configured number of redundant packets
*
* note: we purposely don't allow error_correction_entries to drop to
* zero in this loop; we'd rather send smaller IFPs (and thus reduce
* the image data transfer rate) than sacrifice redundancy completely
*/
for (;;) {
new_max = (udptl->far_max_datagram - 8) / (udptl->error_correction_entries + 1);
if ((new_max < 80) && (udptl->error_correction_entries > 1)) {
/* the max ifp is not large enough, subtract an
* error correction entry and calculate again
* */
--udptl->error_correction_entries;
} else {
break;
}
}
break;
case UDPTL_ERROR_CORRECTION_FEC:
/* need room for sequence number, length indicators and a
* a single IFP of the maximum size expected
*/
new_max = (udptl->far_max_datagram - 10) / 2;
break;
}
/* subtract 5% of space for insurance */
udptl->far_max_ifp = new_max * 0.95;
}
enum ast_t38_ec_modes ast_udptl_get_error_correction_scheme(const struct ast_udptl *udptl)
{
return udptl->error_correction_scheme;
}
void ast_udptl_set_error_correction_scheme(struct ast_udptl *udptl, enum ast_t38_ec_modes ec)
{
udptl->error_correction_scheme = ec;
switch (ec) {
case UDPTL_ERROR_CORRECTION_FEC:
udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
if (udptl->error_correction_entries == 0) {
udptl->error_correction_entries = 3;
}
if (udptl->error_correction_span == 0) {
udptl->error_correction_span = 3;
}
break;
case UDPTL_ERROR_CORRECTION_REDUNDANCY:
udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
if (udptl->error_correction_entries == 0) {
udptl->error_correction_entries = 3;
}
break;
default:
/* nothing to do */
break;
};
/* reset calculated values so they'll be computed again */
udptl->local_max_datagram = -1;
udptl->far_max_ifp = -1;
}
void ast_udptl_set_local_max_ifp(struct ast_udptl *udptl, unsigned int max_ifp)
{
/* make sure max_ifp is a positive value since a cast will take place when
* when setting local_max_ifp */
if ((signed int) max_ifp > 0) {
udptl->local_max_ifp = max_ifp;
/* reset calculated values so they'll be computed again */
udptl->local_max_datagram = -1;
}
}
unsigned int ast_udptl_get_local_max_datagram(struct ast_udptl *udptl)
{
if (udptl->local_max_datagram == -1) {
calculate_local_max_datagram(udptl);
}
/* this function expects a unsigned value in return. */
if (udptl->local_max_datagram < 0) {
return 0;
}
return udptl->local_max_datagram;
}
void ast_udptl_set_far_max_datagram(struct ast_udptl *udptl, unsigned int max_datagram)
{
if (!max_datagram || (max_datagram > FAX_MAX_DATAGRAM_LIMIT)) {
udptl->far_max_datagram = DEFAULT_FAX_MAX_DATAGRAM;
} else {
udptl->far_max_datagram = max_datagram;
}
/* reset calculated values so they'll be computed again */
udptl->far_max_ifp = -1;
}
unsigned int ast_udptl_get_far_max_datagram(const struct ast_udptl *udptl)
{
if (udptl->far_max_datagram < 0) {
return 0;
}
return udptl->far_max_datagram;
}
unsigned int ast_udptl_get_far_max_ifp(struct ast_udptl *udptl)
{
if (udptl->far_max_ifp == -1) {
calculate_far_max_ifp(udptl);
}
if (udptl->far_max_ifp < 0) {
return 0;
}
return udptl->far_max_ifp;
}
struct ast_udptl *ast_udptl_new_with_bindaddr(struct ast_sched_context *sched, struct io_context *io, int callbackmode, struct ast_sockaddr *addr)
{
struct ast_udptl *udptl;
int x;
int startplace;
int i;
long int flags;
if (!(udptl = ast_calloc(1, sizeof(*udptl))))
return NULL;
udptl->error_correction_span = udptlfecspan;
udptl->error_correction_entries = udptlfecentries;
udptl->far_max_datagram = -1;
udptl->far_max_ifp = -1;
udptl->local_max_ifp = -1;
udptl->local_max_datagram = -1;
for (i = 0; i <= UDPTL_BUF_MASK; i++) {
udptl->rx[i].buf_len = -1;
udptl->tx[i].buf_len = -1;
}
if ((udptl->fd = socket(ast_sockaddr_is_ipv6(addr) ?
AF_INET6 : AF_INET, SOCK_DGRAM, 0)) < 0) {
ast_free(udptl);
ast_log(LOG_WARNING, "Unable to allocate socket: %s\n", strerror(errno));
return NULL;
}
flags = fcntl(udptl->fd, F_GETFL);
fcntl(udptl->fd, F_SETFL, flags | O_NONBLOCK);
#ifdef SO_NO_CHECK
if (nochecksums)
setsockopt(udptl->fd, SOL_SOCKET, SO_NO_CHECK, &nochecksums, sizeof(nochecksums));
#endif
/* Find us a place */
x = (udptlstart == udptlend) ? udptlstart : (ast_random() % (udptlend - udptlstart)) + udptlstart;
if (use_even_ports && (x & 1)) {
++x;
}
startplace = x;
for (;;) {
ast_sockaddr_copy(&udptl->us, addr);
ast_sockaddr_set_port(&udptl->us, x);
if (ast_bind(udptl->fd, &udptl->us) == 0) {
break;
}
if (errno != EADDRINUSE) {
ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno));
close(udptl->fd);
ast_free(udptl);
return NULL;
}
if (use_even_ports) {
x += 2;
} else {
++x;
}
if (x > udptlend)
x = udptlstart;
if (x == startplace) {
ast_log(LOG_WARNING, "No UDPTL ports remaining\n");
close(udptl->fd);
ast_free(udptl);
return NULL;
}
}
if (io && sched && callbackmode) {
/* Operate this one in a callback mode */
udptl->sched = sched;
udptl->io = io;
udptl->ioid = ast_io_add(udptl->io, udptl->fd, udptlread, AST_IO_IN, udptl);
}
return udptl;
}
void ast_udptl_set_tag(struct ast_udptl *udptl, const char *format, ...)
{
va_list ap;
if (udptl->tag) {
ast_free(udptl->tag);
udptl->tag = NULL;
}
va_start(ap, format);
if (ast_vasprintf(&udptl->tag, format, ap) == -1) {
udptl->tag = NULL;
}
va_end(ap);
}
int ast_udptl_setqos(struct ast_udptl *udptl, unsigned int tos, unsigned int cos)
{
return ast_netsock_set_qos(udptl->fd, tos, cos, "UDPTL");
}
void ast_udptl_set_peer(struct ast_udptl *udptl, const struct ast_sockaddr *them)
{
ast_sockaddr_copy(&udptl->them, them);
}
void ast_udptl_get_peer(const struct ast_udptl *udptl, struct ast_sockaddr *them)
{
ast_sockaddr_copy(them, &udptl->them);
}
void ast_udptl_get_us(const struct ast_udptl *udptl, struct ast_sockaddr *us)
{
ast_sockaddr_copy(us, &udptl->us);
}
void ast_udptl_stop(struct ast_udptl *udptl)
{
ast_sockaddr_setnull(&udptl->them);
}
void ast_udptl_destroy(struct ast_udptl *udptl)
{
if (udptl->ioid)
ast_io_remove(udptl->io, udptl->ioid);
if (udptl->fd > -1)
close(udptl->fd);
if (udptl->tag)
ast_free(udptl->tag);
ast_free(udptl);
}
int ast_udptl_write(struct ast_udptl *s, struct ast_frame *f)
{
unsigned int seq;
unsigned int len = f->datalen;
int res;
/* if no max datagram size is provided, use default value */
const int bufsize = (s->far_max_datagram > 0) ? s->far_max_datagram : DEFAULT_FAX_MAX_DATAGRAM;
uint8_t buf[bufsize];
memset(buf, 0, sizeof(buf));
/* If we have no peer, return immediately */
if (ast_sockaddr_isnull(&s->them)) {
return 0;
}
/* If there is no data length, return immediately */
if (f->datalen == 0)
return 0;
if ((f->frametype != AST_FRAME_MODEM) ||
(f->subclass.codec != AST_MODEM_T38)) {
ast_log(LOG_WARNING, "(%s): UDPTL can only send T.38 data.\n",
LOG_TAG(s));
return -1;
}
if (len > s->far_max_ifp) {
ast_log(LOG_WARNING,
"(%s): UDPTL asked to send %d bytes of IFP when far end only prepared to accept %d bytes; data loss will occur."
"You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.\n",
LOG_TAG(s), len, s->far_max_ifp);
len = s->far_max_ifp;
}
/* Save seq_no for debug output because udptl_build_packet increments it */
seq = s->tx_seq_no & 0xFFFF;
/* Cook up the UDPTL packet, with the relevant EC info. */
len = udptl_build_packet(s, buf, sizeof(buf), f->data.ptr, len);
if ((signed int) len > 0 && !ast_sockaddr_isnull(&s->them)) {
if ((res = ast_sendto(s->fd, buf, len, 0, &s->them)) < 0)
ast_log(LOG_NOTICE, "(%s): UDPTL Transmission error to %s: %s\n",
LOG_TAG(s), ast_sockaddr_stringify(&s->them), strerror(errno));
if (udptl_debug_test_addr(&s->them))
ast_verb(1, "UDPTL (%s): packet to %s (type %d, seq %d, len %d)\n",
LOG_TAG(s), ast_sockaddr_stringify(&s->them), 0, seq, len);
}
return 0;
}
void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto)
{
AST_RWLIST_WRLOCK(&protos);
AST_RWLIST_REMOVE(&protos, proto, list);
AST_RWLIST_UNLOCK(&protos);
}
int ast_udptl_proto_register(struct ast_udptl_protocol *proto)
{
struct ast_udptl_protocol *cur;
AST_RWLIST_WRLOCK(&protos);
AST_RWLIST_TRAVERSE(&protos, cur, list) {
if (cur->type == proto->type) {
ast_log(LOG_WARNING, "Tried to register same protocol '%s' twice\n", cur->type);
AST_RWLIST_UNLOCK(&protos);
return -1;
}
}
AST_RWLIST_INSERT_TAIL(&protos, proto, list);
AST_RWLIST_UNLOCK(&protos);
return 0;
}
static struct ast_udptl_protocol *get_proto(struct ast_channel *chan)
{
struct ast_udptl_protocol *cur = NULL;
AST_RWLIST_RDLOCK(&protos);
AST_RWLIST_TRAVERSE(&protos, cur, list) {
if (cur->type == chan->tech->type)
break;
}
AST_RWLIST_UNLOCK(&protos);
return cur;
}
int ast_udptl_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc)
{
struct ast_frame *f;
struct ast_channel *who;
struct ast_channel *cs[3];
struct ast_udptl *p0;
struct ast_udptl *p1;
struct ast_udptl_protocol *pr0;
struct ast_udptl_protocol *pr1;
struct ast_sockaddr ac0;
struct ast_sockaddr ac1;
struct ast_sockaddr t0;
struct ast_sockaddr t1;
void *pvt0;
void *pvt1;
int to;
ast_channel_lock(c0);
while (ast_channel_trylock(c1)) {
ast_channel_unlock(c0);
usleep(1);
ast_channel_lock(c0);
}
pr0 = get_proto(c0);
pr1 = get_proto(c1);
if (!pr0) {
ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c0->name);
ast_channel_unlock(c0);
ast_channel_unlock(c1);
return -1;
}
if (!pr1) {
ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c1->name);
ast_channel_unlock(c0);
ast_channel_unlock(c1);
return -1;
}
pvt0 = c0->tech_pvt;
pvt1 = c1->tech_pvt;
p0 = pr0->get_udptl_info(c0);
p1 = pr1->get_udptl_info(c1);
if (!p0 || !p1) {
/* Somebody doesn't want to play... */
ast_channel_unlock(c0);
ast_channel_unlock(c1);
return -2;
}
if (pr0->set_udptl_peer(c0, p1)) {
ast_log(LOG_WARNING, "Channel '%s' failed to talk to '%s'\n", c0->name, c1->name);
memset(&ac1, 0, sizeof(ac1));
} else {
/* Store UDPTL peer */
ast_udptl_get_peer(p1, &ac1);
}
if (pr1->set_udptl_peer(c1, p0)) {
ast_log(LOG_WARNING, "Channel '%s' failed to talk back to '%s'\n", c1->name, c0->name);
memset(&ac0, 0, sizeof(ac0));
} else {
/* Store UDPTL peer */
ast_udptl_get_peer(p0, &ac0);
}
ast_channel_unlock(c0);
ast_channel_unlock(c1);
cs[0] = c0;
cs[1] = c1;
cs[2] = NULL;
for (;;) {
if ((c0->tech_pvt != pvt0) ||
(c1->tech_pvt != pvt1) ||
(c0->masq || c0->masqr || c1->masq || c1->masqr)) {
ast_debug(1, "Oooh, something is weird, backing out\n");
/* Tell it to try again later */
return -3;
}
to = -1;
ast_udptl_get_peer(p1, &t1);
ast_udptl_get_peer(p0, &t0);
if (ast_sockaddr_cmp(&t1, &ac1)) {
ast_debug(1, "Oooh, '%s' changed end address to %s\n",
c1->name, ast_sockaddr_stringify(&t1));
ast_debug(1, "Oooh, '%s' was %s\n",
c1->name, ast_sockaddr_stringify(&ac1));
ast_sockaddr_copy(&ac1, &t1);
}
if (ast_sockaddr_cmp(&t0, &ac0)) {
ast_debug(1, "Oooh, '%s' changed end address to %s\n",
c0->name, ast_sockaddr_stringify(&t0));
ast_debug(1, "Oooh, '%s' was %s\n",
c0->name, ast_sockaddr_stringify(&ac0));
ast_sockaddr_copy(&ac0, &t0);
}
who = ast_waitfor_n(cs, 2, &to);
if (!who) {
ast_debug(1, "Ooh, empty read...\n");
/* check for hangup / whentohangup */
if (ast_check_hangup(c0) || ast_check_hangup(c1))
break;
continue;
}
f = ast_read(who);
if (!f) {
*fo = f;
*rc = who;
ast_debug(1, "Oooh, got a %s\n", f ? "digit" : "hangup");
/* That's all we needed */
return 0;
} else {
if (f->frametype == AST_FRAME_MODEM) {
/* Forward T.38 frames if they happen upon us */
if (who == c0) {
ast_write(c1, f);
} else if (who == c1) {
ast_write(c0, f);
}
}
ast_frfree(f);
}
/* Swap priority. Not that it's a big deal at this point */
cs[2] = cs[0];
cs[0] = cs[1];
cs[1] = cs[2];
}
return -1;
}
static char *handle_cli_udptl_set_debug(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
switch (cmd) {
case CLI_INIT:
e->command = "udptl set debug {on|off|ip}";
e->usage =
"Usage: udptl set debug {on|off|ip host[:port]}\n"
" Enable or disable dumping of UDPTL packets.\n"
" If ip is specified, limit the dumped packets to those to and from\n"
" the specified 'host' with optional port.\n";
return NULL;
case CLI_GENERATE:
return NULL;
}
if (a->argc < 4 || a->argc > 5)
return CLI_SHOWUSAGE;
if (a->argc == 4) {
if (!strncasecmp(a->argv[3], "on", 2)) {
udptldebug = 1;
memset(&udptldebugaddr, 0, sizeof(udptldebugaddr));
ast_cli(a->fd, "UDPTL Debugging Enabled\n");
} else if (!strncasecmp(a->argv[3], "off", 3)) {
udptldebug = 0;
ast_cli(a->fd, "UDPTL Debugging Disabled\n");
} else {
return CLI_SHOWUSAGE;
}
} else {
struct ast_sockaddr *addrs;
if (strncasecmp(a->argv[3], "ip", 2))
return CLI_SHOWUSAGE;
if (!ast_sockaddr_resolve(&addrs, a->argv[4], 0, 0)) {
return CLI_SHOWUSAGE;
}
ast_sockaddr_copy(&udptldebugaddr, &addrs[0]);
ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s\n", ast_sockaddr_stringify(&udptldebugaddr));
udptldebug = 1;
ast_free(addrs);
}
return CLI_SUCCESS;
}
static struct ast_cli_entry cli_udptl[] = {
AST_CLI_DEFINE(handle_cli_udptl_set_debug, "Enable/Disable UDPTL debugging")
};
static void __ast_udptl_reload(int reload)
{
struct ast_config *cfg;
const char *s;
struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
cfg = ast_config_load2("udptl.conf", "udptl", config_flags);
if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEUNCHANGED || cfg == CONFIG_STATUS_FILEINVALID) {
return;
}
udptlstart = 4500;
udptlend = 4999;
udptlfecentries = 0;
udptlfecspan = 0;
use_even_ports = 0;
if (cfg) {
if ((s = ast_variable_retrieve(cfg, "general", "udptlstart"))) {
udptlstart = atoi(s);
if (udptlstart < 1024) {
ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
udptlstart = 1024;
}
if (udptlstart > 65535) {
ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
udptlstart = 65535;
}
}
if ((s = ast_variable_retrieve(cfg, "general", "udptlend"))) {
udptlend = atoi(s);
if (udptlend < 1024) {
ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
udptlend = 1024;
}
if (udptlend > 65535) {
ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
udptlend = 65535;
}
}
if ((s = ast_variable_retrieve(cfg, "general", "udptlchecksums"))) {
#ifdef SO_NO_CHECK
if (ast_false(s))
nochecksums = 1;
else
nochecksums = 0;
#else
if (ast_false(s))
ast_log(LOG_WARNING, "Disabling UDPTL checksums is not supported on this operating system!\n");
#endif
}
if ((s = ast_variable_retrieve(cfg, "general", "T38FaxUdpEC"))) {
ast_log(LOG_WARNING, "T38FaxUdpEC in udptl.conf is no longer supported; use the t38pt_udptl configuration option in sip.conf instead.\n");
}
if ((s = ast_variable_retrieve(cfg, "general", "T38FaxMaxDatagram"))) {
ast_log(LOG_WARNING, "T38FaxMaxDatagram in udptl.conf is no longer supported; value is now supplied by T.38 applications.\n");
}
if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECEntries"))) {
udptlfecentries = atoi(s);
if (udptlfecentries < 1) {
ast_log(LOG_WARNING, "Too small UDPTLFECEntries value. Defaulting to 1.\n");
udptlfecentries = 1;
}
if (udptlfecentries > MAX_FEC_ENTRIES) {
ast_log(LOG_WARNING, "Too large UDPTLFECEntries value. Defaulting to %d.\n", MAX_FEC_ENTRIES);
udptlfecentries = MAX_FEC_ENTRIES;
}
}
if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECSpan"))) {
udptlfecspan = atoi(s);
if (udptlfecspan < 1) {
ast_log(LOG_WARNING, "Too small UDPTLFECSpan value. Defaulting to 1.\n");
udptlfecspan = 1;
}
if (udptlfecspan > MAX_FEC_SPAN) {
ast_log(LOG_WARNING, "Too large UDPTLFECSpan value. Defaulting to %d.\n", MAX_FEC_SPAN);
udptlfecspan = MAX_FEC_SPAN;
}
}
if ((s = ast_variable_retrieve(cfg, "general", "use_even_ports"))) {
use_even_ports = ast_true(s);
}
ast_config_destroy(cfg);
}
if (udptlstart >= udptlend) {
ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end ports; defaulting to 4500-4999.\n");
udptlstart = 4500;
udptlend = 4999;
}
if (use_even_ports && (udptlstart & 1)) {
++udptlstart;
ast_log(LOG_NOTICE, "Odd numbered udptlstart specified but use_even_ports enabled. udptlstart is now %d\n", udptlstart);
}
if (use_even_ports && (udptlend & 1)) {
--udptlend;
ast_log(LOG_NOTICE, "Odd numbered udptlend specified but use_event_ports enabled. udptlend is now %d\n", udptlend);
}
ast_verb(2, "UDPTL allocating from port range %d -> %d\n", udptlstart, udptlend);
}
int ast_udptl_reload(void)
{
__ast_udptl_reload(1);
return 0;
}
void ast_udptl_init(void)
{
ast_cli_register_multiple(cli_udptl, ARRAY_LEN(cli_udptl));
__ast_udptl_reload(0);
}
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