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asterisk/main/udptl.c

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/*
* Asterisk -- An open source telephony toolkit.
*
* 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.
*
* 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:
* - udptl.c
* - app_fax.c
*/
/*! \li \ref udptl.c uses the configuration file \ref udptl.conf
* \addtogroup configuration_file Configuration Files
*/
/*!
* \page udptl.conf udptl.conf
* \verbinclude udptl.conf.sample
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
#include <sys/time.h>
#include <signal.h>
#include <fcntl.h>
#include "asterisk/module.h"
#include "asterisk/udptl.h"
#include "asterisk/frame.h"
#include "asterisk/channel.h"
#include "asterisk/acl.h"
#include "asterisk/config_options.h"
#include "asterisk/lock.h"
#include "asterisk/utils.h"
#include "asterisk/netsock2.h"
#include "asterisk/cli.h"
#include "asterisk/unaligned.h"
/*** DOCUMENTATION
<configInfo name="udptl" language="en_US">
<configFile name="udptl.conf">
<configObject name="global">
<synopsis>Global options for configuring UDPTL</synopsis>
<configOption name="udptlstart">
<synopsis>The start of the UDPTL port range</synopsis>
</configOption>
<configOption name="udptlend">
<synopsis>The end of the UDPTL port range</synopsis>
</configOption>
<configOption name="udptlchecksums">
<synopsis>Whether to enable or disable UDP checksums on UDPTL traffic</synopsis>
</configOption>
<configOption name="udptlfecentries">
<synopsis>The number of error correction entries in a UDPTL packet</synopsis>
</configOption>
<configOption name="udptlfecspan">
<synopsis>The span over which parity is calculated for FEC in a UDPTL packet</synopsis>
</configOption>
<configOption name="use_even_ports">
<synopsis>Whether to only use even-numbered UDPTL ports</synopsis>
</configOption>
<configOption name="t38faxudpec">
<synopsis>Removed</synopsis>
</configOption>
<configOption name="t38faxmaxdatagram">
<synopsis>Removed</synopsis>
</configOption>
</configObject>
</configFile>
</configInfo>
***/
#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")
#define DEFAULT_UDPTLSTART 4000
#define DEFAULT_UDPTLEND 4999
static int udptldebug; /*!< Are we debugging? */
static struct ast_sockaddr udptldebugaddr; /*!< Debug packets to/from this host */
#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;
unsigned int tx_seq_no;
unsigned int rx_seq_no;
udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1];
udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1];
};
struct udptl_global_options {
unsigned int start; /*< The UDPTL start port */
unsigned int end; /*< The UDPTL end port */
unsigned int fecentries;
unsigned int fecspan;
unsigned int nochecksums;
unsigned int use_even_ports;
};
static AO2_GLOBAL_OBJ_STATIC(globals);
struct udptl_config {
struct udptl_global_options *general;
};
static void *udptl_snapshot_alloc(void);
static int udptl_pre_apply_config(void);
static struct aco_type general_option = {
.type = ACO_GLOBAL,
.name = "global",
.category_match = ACO_WHITELIST_EXACT,
.item_offset = offsetof(struct udptl_config, general),
.category = "general",
};
static struct aco_type *general_options[] = ACO_TYPES(&general_option);
static struct aco_file udptl_conf = {
.filename = "udptl.conf",
.types = ACO_TYPES(&general_option),
};
CONFIG_INFO_CORE("udptl", cfg_info, globals, udptl_snapshot_alloc,
.files = ACO_FILES(&udptl_conf),
.pre_apply_config = udptl_pre_apply_config,
);
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)++;
/* We have a fragment. Currently we don't process fragments. */
ast_debug(1, "UDPTL packet with length greater than 16K received, decoding will fail\n");
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 = 0;
if (decode_length(buf, limit, len, &octet_cnt) != 0)
return -1;
/* Make sure the buffer contains at least the number of bits requested */
if ((*len + octet_cnt) > limit) {
return -1;
}
*p_num_octets = octet_cnt;
*p_object = &buf[*len];
*len += octet_cnt;
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) {
enclen = encode_length(buf, len, num_octets);
if (enclen + *len > buflen) {
ast_log(LOG_ERROR, "UDPTL (%s): Buffer overflow detected (%u + %u > %u)\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;
unsigned int ptr; /* an index that keeps track of how much of the UDPTL packet has been processed */
int seq_no;
const uint8_t *ifp = NULL;
const uint8_t *data = NULL;
unsigned int ifp_len = 0;
int repaired[16];
const uint8_t *bufs[ARRAY_LEN(s->f) - 1];
unsigned int lengths[ARRAY_LEN(s->f) - 1];
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;
/* UDPTL sequence numbers are 16 bit so after 0xFFFF comes
0 which breaks all packet recovery logic. To fix this
if we see that next expected packet (rx_seq_no) is close
to or beyond the wrap around limit & the received packet
is still near zero, then we 'unwrap' the received seqno
so it has the value it would have had. After a 16
packet grace period (there shouldn't be more than
that many recovery packets) we wrap the expected
sequence number around and things can return back
to normal */
if (seq_no < 0x000F && s->rx_seq_no > 0xFFF0) {
/* received seq_no has wrapped adjust it */
seq_no += 0x10000;
} else {
/* otherwise make sure expected rx_seq_no is properly wrapped */
s->rx_seq_no &= 0xFFFF;
}
/* 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. */
int total_count = 0;
do {
unsigned int count;
if ((stat2 = decode_length(buf, len, &ptr, &count)) < 0)
return -1;
for (i = 0; i < count && total_count + i < ARRAY_LEN(bufs); i++) {
if ((stat1 = decode_open_type(buf, len, &ptr, &bufs[total_count + i], &lengths[total_count + i])) != 0) {
return -1;
}
/* valid secondaries can contain zero-length packets that should be ignored */
if (!bufs[total_count + i] || !lengths[total_count + i]) {
/* drop the count of items to process and reuse the buffers that were just set */
i--;
count--;
}
}
total_count += i;
}
while (stat2 > 0 && total_count < ARRAY_LEN(bufs));
/* 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 */
ast_debug(3, "Recovering lost packet via secondary %d, len %u\n", seq_no - i, lengths[i - 1]);
s->f[ifp_no].frametype = AST_FRAME_MODEM;
s->f[ifp_no].subclass.integer = 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
{
int j;
int l;
int x;
/* 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++];
if (entries > MAX_FEC_ENTRIES) {
return -1;
}
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, "%02hhX ", 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) {
int m;
if (s->rx[l].fec_len[0] <= 0)
continue;
for (m = 0; m < s->rx[l].fec_entries; m++) {
int k;
int which;
int limit = (l + m) & UDPTL_BUF_MASK;
/* only repair buffers that actually exist! */
if (seq_no <= (s->rx[l].fec_span * s->rx[l].fec_entries) - m) {
continue;
}
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.integer = 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.integer = 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] = { 0, };
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. */
encode_length(buf, &len, 0);
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. */
encode_length(buf, &len, entries);
/* 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, "UDPTL (%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 unconstrained 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;
}
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;
uint8_t *buf;
buf = udptl->rawdata + AST_FRIENDLY_OFFSET;
/* Cache where the header will go */
res = ast_recvfrom(udptl->fd,
buf,
sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET,
0,
&addr);
if (res < 0) {
if (errno != EAGAIN)
ast_log(LOG_WARNING, "UDPTL (%s): 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 early media isn't turned on for the channel driver, it's going to
* drop this frame. By that time though, udptl has already incremented
* the expected sequence number so if the CPE re-sends, the second frame
* will be dropped as a dup even though the first frame never went through.
* So we drop the frame here if the channel isn't up. 'tag' is set by the
* channel drivers on T38_ENABLED or T38_PEER_REINVITE.
*/
if (udptl->tag == NULL) {
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 (%s): NAT, Using address %s\n",
LOG_TAG(udptl), ast_sockaddr_stringify(&udptl->them));
}
}
if (udptl_debug_test_addr(&addr)) {
int seq_no;
/* Decode sequence number just for verbose message. */
if (res < 2) {
/* Short packet. */
seq_no = -1;
} else {
seq_no = (buf[0] << 8) | buf[1];
}
ast_verb(1, "UDPTL (%s): packet from %s (seq %d, len %d)\n",
LOG_TAG(udptl), ast_sockaddr_stringify(&addr), seq_no, res);
}
if (udptl_rx_packet(udptl, buf, 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, "UDPTL (%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, "UDPTL (%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;
RAII_VAR(struct udptl_config *, cfg, ao2_global_obj_ref(globals), ao2_cleanup);
if (!cfg || !cfg->general) {
ast_log(LOG_ERROR, "Could not access global udptl options!\n");
return NULL;
}
if (!(udptl = ast_calloc(1, sizeof(*udptl)))) {
return NULL;
}
udptl->error_correction_span = cfg->general->fecspan;
udptl->error_correction_entries = cfg->general->fecentries;
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 = ast_socket_nonblock(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;
}
#ifdef SO_NO_CHECK
if (cfg->general->nochecksums)
setsockopt(udptl->fd, SOL_SOCKET, SO_NO_CHECK, &cfg->general->nochecksums, sizeof(cfg->general->nochecksums));
#endif
/* Find us a place */
x = (cfg->general->start == cfg->general->end) ? cfg->general->start : (ast_random() % (cfg->general->end - cfg->general->start)) + cfg->general->start;
if (cfg->general->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 && errno != EACCES) {
ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno));
close(udptl->fd);
ast_free(udptl);
return NULL;
}
if (cfg->general->use_even_ports) {
x += 2;
} else {
++x;
}
if (x > cfg->general->end)
x = cfg->general->start;
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;
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_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;
/* 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.integer != AST_MODEM_T38)) {
ast_log(LOG_WARNING, "UDPTL (%s): UDPTL can only send T.38 data.\n",
LOG_TAG(s));
return -1;
}
if (len > s->far_max_ifp) {
ast_log(LOG_WARNING,
"UDPTL (%s): UDPTL asked to send %u 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 (ast_sendto(s->fd, buf, len, 0, &s->them) < 0) {
ast_log(LOG_NOTICE, "UDPTL (%s): 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 (seq %u, len %u)\n",
LOG_TAG(s), ast_sockaddr_stringify(&s->them), seq, len);
}
}
return 0;
}
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 char *handle_cli_show_config(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
RAII_VAR(struct udptl_config *, cfg, NULL, ao2_cleanup);
switch (cmd) {
case CLI_INIT:
e->command = "udptl show config";
e->usage =
"Usage: udptl show config\n"
" Display UDPTL configuration options\n";
return NULL;
case CLI_GENERATE:
return NULL;
}
if (!(cfg = ao2_global_obj_ref(globals))) {
return CLI_FAILURE;
}
ast_cli(a->fd, "UDPTL Global options\n");
ast_cli(a->fd, "--------------------\n");
ast_cli(a->fd, "udptlstart: %u\n", cfg->general->start);
ast_cli(a->fd, "udptlend: %u\n", cfg->general->end);
ast_cli(a->fd, "udptlfecentries: %u\n", cfg->general->fecentries);
ast_cli(a->fd, "udptlfecspan: %u\n", cfg->general->fecspan);
ast_cli(a->fd, "use_even_ports: %s\n", AST_CLI_YESNO(cfg->general->use_even_ports));
ast_cli(a->fd, "udptlchecksums: %s\n", AST_CLI_YESNO(!cfg->general->nochecksums));
return CLI_SUCCESS;
}
static struct ast_cli_entry cli_udptl[] = {
AST_CLI_DEFINE(handle_cli_udptl_set_debug, "Enable/Disable UDPTL debugging"),
AST_CLI_DEFINE(handle_cli_show_config, "Show UDPTL config options"),
};
static void udptl_config_destructor(void *obj)
{
struct udptl_config *cfg = obj;
ao2_cleanup(cfg->general);
}
static void *udptl_snapshot_alloc(void)
{
struct udptl_config *cfg;
if (!(cfg = ao2_alloc(sizeof(*cfg), udptl_config_destructor))) {
return NULL;
}
if (!(cfg->general = ao2_alloc(sizeof(*cfg->general), NULL))) {
ao2_ref(cfg, -1);
return NULL;
}
return cfg;
}
static int removed_options_handler(const struct aco_option *opt, struct ast_variable *var, void *obj)
{
if (!strcasecmp(var->name, "t38faxudpec")) {
ast_log(LOG_WARNING, "t38faxudpec in udptl.conf is no longer supported.\n");
} else if (!strcasecmp(var->name, "t38faxmaxdatagram")) {
ast_log(LOG_WARNING, "t38faxmaxdatagram in udptl.conf is no longer supported; value is now supplied by T.38 applications.\n");
}
return 0;
}
static void __ast_udptl_reload(int reload)
{
if (aco_process_config(&cfg_info, reload) == ACO_PROCESS_ERROR) {
if (!reload) {
RAII_VAR(struct udptl_config *, udptl_cfg, udptl_snapshot_alloc(), ao2_cleanup);
if (aco_set_defaults(&general_option, "general", udptl_cfg->general)) {
ast_log(LOG_ERROR, "Failed to load udptl.conf and failed to initialize defaults.\n");
return;
}
ast_log(LOG_NOTICE, "Could not load udptl config; using defaults\n");
ao2_global_obj_replace_unref(globals, udptl_cfg);
}
}
}
static int udptl_pre_apply_config(void) {
struct udptl_config *cfg = aco_pending_config(&cfg_info);
if (!cfg->general) {
return -1;
}
#ifndef SO_NO_CHECK
if (cfg->general->nochecksums) {
ast_log(LOG_WARNING, "Disabling UDPTL checksums is not supported on this operating system!\n");
cfg->general->nochecksums = 0;
}
#endif
/* Fix up any global config values that we can handle before replacing the config */
if (cfg->general->use_even_ports && (cfg->general->start & 1)) {
++cfg->general->start;
ast_log(LOG_NOTICE, "Odd numbered udptlstart specified but use_even_ports enabled. udptlstart is now %u\n", cfg->general->start);
}
if (cfg->general->start > cfg->general->end) {
ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end ports; defaulting to %s-%s.\n", __stringify(DEFAULT_UDPTLSTART), __stringify(DEFAULT_UDPTLEND));
cfg->general->start = DEFAULT_UDPTLSTART;
cfg->general->end = DEFAULT_UDPTLEND;
}
if (cfg->general->use_even_ports && (cfg->general->end & 1)) {
--cfg->general->end;
ast_log(LOG_NOTICE, "Odd numbered udptlend specified but use_even_ports enabled. udptlend is now %u\n", cfg->general->end);
}
return 0;
}
static int reload_module(void)
{
__ast_udptl_reload(1);
return 0;
}
/*!
* \internal
* \brief Clean up resources on Asterisk shutdown
*/
static int unload_module(void)
{
ast_cli_unregister_multiple(cli_udptl, ARRAY_LEN(cli_udptl));
ao2_t_global_obj_release(globals, "Unref udptl global container in shutdown");
aco_info_destroy(&cfg_info);
return 0;
}
static int load_module(void)
{
if (aco_info_init(&cfg_info)) {
return AST_MODULE_LOAD_FAILURE;
}
aco_option_register(&cfg_info, "udptlstart", ACO_EXACT, general_options, __stringify(DEFAULT_UDPTLSTART),
OPT_UINT_T, PARSE_IN_RANGE | PARSE_DEFAULT,
FLDSET(struct udptl_global_options, start), DEFAULT_UDPTLSTART, 1024, 65535);
aco_option_register(&cfg_info, "udptlend", ACO_EXACT, general_options, __stringify(DEFAULT_UDPTLEND),
OPT_UINT_T, PARSE_IN_RANGE | PARSE_DEFAULT,
FLDSET(struct udptl_global_options, end), DEFAULT_UDPTLEND, 1024, 65535);
aco_option_register(&cfg_info, "udptlfecentries", ACO_EXACT, general_options, NULL,
OPT_UINT_T, PARSE_IN_RANGE | PARSE_RANGE_DEFAULTS,
FLDSET(struct udptl_global_options, fecentries), 1, MAX_FEC_ENTRIES);
aco_option_register(&cfg_info, "udptlfecspan", ACO_EXACT, general_options, NULL,
OPT_UINT_T, PARSE_IN_RANGE | PARSE_RANGE_DEFAULTS,
FLDSET(struct udptl_global_options, fecspan), 1, MAX_FEC_SPAN);
aco_option_register(&cfg_info, "udptlchecksums", ACO_EXACT, general_options, "yes",
OPT_BOOL_T, 0, FLDSET(struct udptl_global_options, nochecksums));
aco_option_register(&cfg_info, "use_even_ports", ACO_EXACT, general_options, "no",
OPT_BOOL_T, 1, FLDSET(struct udptl_global_options, use_even_ports));
aco_option_register_custom(&cfg_info, "t38faxudpec", ACO_EXACT, general_options, NULL, removed_options_handler, 0);
aco_option_register_custom(&cfg_info, "t38faxmaxdatagram", ACO_EXACT, general_options, NULL, removed_options_handler, 0);
__ast_udptl_reload(0);
ast_cli_register_multiple(cli_udptl, ARRAY_LEN(cli_udptl));
return AST_MODULE_LOAD_SUCCESS;
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "UDPTL",
.support_level = AST_MODULE_SUPPORT_CORE,
.load = load_module,
.unload = unload_module,
.reload = reload_module,
.load_pri = AST_MODPRI_CORE,
.requires = "extconfig",
);
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