Changes to add udptl to asterisk (preliminary merging of the t.38 patch)
authorMatthew Fredrickson <creslin@digium.com>
Thu, 12 Jan 2006 17:12:12 +0000 (17:12 +0000)
committerMatthew Fredrickson <creslin@digium.com>
Thu, 12 Jan 2006 17:12:12 +0000 (17:12 +0000)
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@8014 65c4cc65-6c06-0410-ace0-fbb531ad65f3

Makefile
include/asterisk/udptl.h [new file with mode: 0644]
udptl.c [new file with mode: 0644]

index 16766d0..688f8c2 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -346,7 +346,7 @@ SUBDIRS=res channels pbx apps codecs formats agi cdr funcs utils stdtime
 OBJS=io.o sched.o logger.o frame.o loader.o config.o channel.o \
        translate.o file.o say.o pbx.o cli.o md5.o term.o \
        ulaw.o alaw.o callerid.o fskmodem.o image.o app.o \
-       cdr.o tdd.o acl.o rtp.o manager.o asterisk.o \
+       cdr.o tdd.o acl.o rtp.o udptl.o manager.o asterisk.o \
        dsp.o chanvars.o indications.o autoservice.o db.o privacy.o \
        astmm.o enum.o srv.o dns.o aescrypt.o aestab.o aeskey.o \
        utils.o plc.o jitterbuf.o dnsmgr.o devicestate.o \
@@ -417,6 +417,8 @@ LIBS+=-lssl
 
 INSTALL=install
 
+CFLAGS+=-DT38_SUPPORT
+
 _all: all
        @echo " +--------- Asterisk Build Complete ---------+"  
        @echo " + Asterisk has successfully been built, but +"  
diff --git a/include/asterisk/udptl.h b/include/asterisk/udptl.h
new file mode 100644 (file)
index 0000000..5b80980
--- /dev/null
@@ -0,0 +1,119 @@
+/*
+ * 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) 1999-2004, Digium, Inc.
+ *
+ * Steve Underwood <steveu@coppice.org>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License
+ *
+ * This version is disclaimed to DIGIUM for inclusion in the Asterisk project.
+ */
+
+#ifndef _ASTERISK_UDPTL_H
+#define _ASTERISK_UDPTL_H
+
+#include "asterisk/frame.h"
+#include "asterisk/io.h"
+#include "asterisk/sched.h"
+#include "asterisk/channel.h"
+
+#include <netinet/in.h>
+
+enum
+{
+    UDPTL_ERROR_CORRECTION_NONE,
+    UDPTL_ERROR_CORRECTION_FEC,
+    UDPTL_ERROR_CORRECTION_REDUNDANCY
+};
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+struct ast_udptl_protocol {
+       /* Get UDPTL struct, or NULL if unwilling to transfer */
+       struct ast_udptl *(*get_udptl_info)(struct ast_channel *chan);
+       /* Set UDPTL peer */
+       int (* const set_udptl_peer)(struct ast_channel *chan, struct ast_udptl *peer);
+       const char * const type;
+       struct ast_udptl_protocol *next;
+};
+
+struct ast_udptl;
+
+typedef int (*ast_udptl_callback)(struct ast_udptl *udptl, struct ast_frame *f, void *data);
+
+struct ast_udptl *ast_udptl_new(struct sched_context *sched, struct io_context *io, int callbackmode);
+
+struct ast_udptl *ast_udptl_new_with_bindaddr(struct sched_context *sched, struct io_context *io, int callbackmode, struct in_addr in);
+
+void ast_udptl_set_peer(struct ast_udptl *udptl, struct sockaddr_in *them);
+
+void ast_udptl_get_peer(struct ast_udptl *udptl, struct sockaddr_in *them);
+
+void ast_udptl_get_us(struct ast_udptl *udptl, struct sockaddr_in *us);
+
+void ast_udptl_destroy(struct ast_udptl *udptl);
+
+void ast_udptl_reset(struct ast_udptl *udptl);
+
+void ast_udptl_set_callback(struct ast_udptl *udptl, ast_udptl_callback callback);
+
+void ast_udptl_set_data(struct ast_udptl *udptl, void *data);
+
+int ast_udptl_write(struct ast_udptl *udptl, struct ast_frame *f);
+
+struct ast_frame *ast_udptl_read(struct ast_udptl *udptl);
+
+int ast_udptl_fd(struct ast_udptl *udptl);
+
+int ast_udptl_settos(struct ast_udptl *udptl, int tos);
+
+void ast_udptl_set_m_type(struct ast_udptl* udptl, int pt);
+
+void ast_udptl_set_udptlmap_type(struct ast_udptl* udptl, int pt,
+                        char* mimeType, char* mimeSubtype);
+
+int ast_udptl_lookup_code(struct ast_udptl* udptl, int isAstFormat, int code);
+
+void ast_udptl_offered_from_local(struct ast_udptl* udptl, int local);
+
+int ast_udptl_get_error_correction_scheme(struct ast_udptl* udptl);
+
+void ast_udptl_set_error_correction_scheme(struct ast_udptl* udptl, int ec);
+
+int ast_udptl_get_local_max_datagram(struct ast_udptl* udptl);
+
+void ast_udptl_set_local_max_datagram(struct ast_udptl* udptl, int max_datagram);
+
+int ast_udptl_get_far_max_datagram(struct ast_udptl* udptl);
+
+void ast_udptl_set_far_max_datagram(struct ast_udptl* udptl, int max_datagram);
+
+void ast_udptl_get_current_formats(struct ast_udptl* udptl,
+                            int* astFormats, int* nonAstFormats);
+
+void ast_udptl_setnat(struct ast_udptl *udptl, int nat);
+
+int ast_udptl_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc);
+
+int ast_udptl_proto_register(struct ast_udptl_protocol *proto);
+
+void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto);
+
+void ast_udptl_stop(struct ast_udptl *udptl);
+
+void ast_udptl_init(void);
+
+void ast_udptl_reload(void);
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}
+#endif
+
+#endif
diff --git a/udptl.c b/udptl.c
new file mode 100644 (file)
index 0000000..71068d3
--- /dev/null
+++ b/udptl.c
@@ -0,0 +1,1261 @@
+/*
+ * 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) 1999-2004, Digium, Inc.
+ *
+ * Steve Underwood <steveu@coppice.org>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License
+ *
+ * This version is disclaimed to DIGIUM for inclusion in the Asterisk project.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <signal.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <netinet/in.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <fcntl.h>
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/udptl.h"
+#include "asterisk/frame.h"
+#include "asterisk/logger.h"
+#include "asterisk/options.h"
+#include "asterisk/channel.h"
+#include "asterisk/acl.h"
+#include "asterisk/channel.h"
+#include "asterisk/config.h"
+#include "asterisk/lock.h"
+#include "asterisk/utils.h"
+#include "asterisk/cli.h"
+#include "asterisk/unaligned.h"
+#include "asterisk/utils.h"
+
+#define UDPTL_MTU              1200
+
+#if !defined(FALSE)
+#define FALSE 0
+#endif
+#if !defined(TRUE)
+#define TRUE (!FALSE)
+#endif
+
+static int udptlstart = 0;
+static int udptlend = 0;
+static int udptldebug = 0;                     /* Are we debugging? */
+static struct sockaddr_in udptldebugaddr;      /* Debug packets to/from this host */
+#ifdef SO_NO_CHECK
+static int nochecksums = 0;
+#endif
+static int udptlfectype = 0;
+static int udptlfecentries = 0;
+static int udptlfecspan = 0;
+static int udptlmaxdatagram = 0;
+
+#define LOCAL_FAX_MAX_DATAGRAM      400
+#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];
+       int fec_len[MAX_FEC_ENTRIES];
+       uint8_t fec[MAX_FEC_ENTRIES][LOCAL_FAX_MAX_DATAGRAM];
+       int fec_span;
+       int fec_entries;
+} udptl_fec_rx_buffer_t;
+
+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 sockaddr_in us;
+       struct sockaddr_in them;
+       int *ioid;
+       uint16_t seqno;
+       struct sched_context *sched;
+       struct io_context *io;
+       void *data;
+       ast_udptl_callback callback;
+       int udptl_offered_from_local;
+
+       /*! This option indicates the error correction scheme used in transmitted UDPTL
+           packets. */
+       int error_correction_scheme;
+
+       /*! This option indicates the number of error correction entries transmitted in
+           UDPTL packets. */
+       int error_correction_entries;
+
+       /*! This option indicates the span of the error correction entries in transmitted
+           UDPTL packets (FEC only). */
+       int error_correction_span;
+
+       /*! This option indicates the maximum size of a UDPTL packet that can be accepted by
+           the remote device. */
+       int far_max_datagram_size;
+
+       /*! This option indicates the maximum size of a UDPTL packet that we are prepared to
+           accept. */
+       int local_max_datagram_size;
+
+       int verbose;
+
+       struct sockaddr_in far;
+
+       int tx_seq_no;
+       int rx_seq_no;
+       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 struct ast_udptl_protocol *protos = NULL;
+
+static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, int len);
+static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, uint8_t *ifp, int ifp_len);
+
+static inline int udptl_debug_test_addr(struct sockaddr_in *addr)
+{
+       if (udptldebug == 0)
+               return 0;
+       if (udptldebugaddr.sin_addr.s_addr) {
+               if (((ntohs(udptldebugaddr.sin_port) != 0)
+                       && (udptldebugaddr.sin_port != addr->sin_port))
+                       || (udptldebugaddr.sin_addr.s_addr != addr->sin_addr.s_addr))
+               return 0;
+       }
+       return 1;
+}
+
+static int decode_length(uint8_t *buf, int limit, int *len, int *pvalue)
+{
+       if ((buf[*len] & 0x80) == 0) {
+               if (*len >= limit)
+                       return -1;
+               *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;
+       }
+       if (*len >= limit)
+               return -1;
+       *pvalue = (buf[*len] & 0x3F) << 14;
+       (*len)++;
+       /* Indicate we have a fragment */
+       return 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+static int decode_open_type(uint8_t *buf, int limit, int *len, const uint8_t **p_object, int *p_num_octets)
+{
+       int octet_cnt;
+       int octet_idx;
+       int stat;
+       int i;
+       const uint8_t **pbuf;
+
+       for (octet_idx = 0, *p_num_octets = 0;  ;  octet_idx += octet_cnt) {
+               if ((stat = 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 (stat == 0)
+                       break;
+       }
+       return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+static int encode_length(uint8_t *buf, int *len, int value)
+{
+       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(uint8_t *buf, int *len, const uint8_t *data, int num_octets)
+{
+       int enclen;
+       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 > 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, int len)
+{
+       int stat;
+       int stat2;
+       int i;
+       int j;
+       int k;
+       int l;
+       int m;
+       int x;
+       int limit;
+       int which;
+       int ptr;
+       int count;
+       int total_count;
+       int seq_no;
+       const uint8_t *ifp;
+       const uint8_t *data;
+       int ifp_len;
+       int repaired[16];
+       const uint8_t *bufs[16];
+       int lengths[16];
+       int span;
+       int entries;
+       int ifp_no;
+
+       ptr = 0;
+       ifp_no = 0;
+       s->f[0].prev = NULL;
+       s->f[0].next = NULL;
+
+       /* Decode seq_number */
+       if (ptr + 2 > len)
+               return -1;
+       seq_no = (buf[0] << 8) | buf[1];
+       ptr += 2;
+
+       /* Break out the primary packet */
+       if ((stat = 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 ((stat = 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 = AST_MODEM_T38;
+
+                                       s->f[ifp_no].mallocd = 0;
+                                       //s->f[ifp_no].???seq_no = seq_no - i;
+                                       s->f[ifp_no].datalen = lengths[i - 1];
+                                       s->f[ifp_no].data = (uint8_t *) bufs[i - 1];
+                                       s->f[ifp_no].offset = 0;
+                                       s->f[ifp_no].src = "UDPTL";
+                                       if (ifp_no > 0) {
+                                               s->f[ifp_no].prev = &s->f[ifp_no - 1];
+                                               s->f[ifp_no - 1].next = &s->f[ifp_no];
+                                       }
+                                       s->f[ifp_no].next = 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 = AST_MODEM_T38;
+                       
+                       s->f[ifp_no].mallocd = 0;
+                       //s->f[ifp_no].???seq_no = seq_no;
+                       s->f[ifp_no].datalen = ifp_len;
+                       s->f[ifp_no].data = (uint8_t *) ifp;
+                       s->f[ifp_no].offset = 0;
+                       s->f[ifp_no].src = "UDPTL";
+                       if (ifp_no > 0) {
+                               s->f[ifp_no].prev = &s->f[ifp_no - 1];
+                               s->f[ifp_no - 1].next = &s->f[ifp_no];
+                       }
+                       s->f[ifp_no].next = NULL;
+               }
+       }
+       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 ((stat = 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 = AST_MODEM_T38;
+                       
+                               s->f[ifp_no].mallocd = 0;
+                               //s->f[ifp_no].???seq_no = j;
+                               s->f[ifp_no].datalen = s->rx[l].buf_len;
+                               s->f[ifp_no].data = s->rx[l].buf;
+                               s->f[ifp_no].offset = 0;
+                               s->f[ifp_no].src = "UDPTL";
+                               if (ifp_no > 0) {
+                                       s->f[ifp_no].prev = &s->f[ifp_no - 1];
+                                       s->f[ifp_no - 1].next = &s->f[ifp_no];
+                               }
+                               s->f[ifp_no].next = NULL;
+                               ifp_no++;
+                       }
+               }
+               /* Decode the primary IFP packet */
+               s->f[ifp_no].frametype = AST_FRAME_MODEM;
+               s->f[ifp_no].subclass = AST_MODEM_T38;
+                       
+               s->f[ifp_no].mallocd = 0;
+               //s->f[ifp_no].???seq_no = j;
+               s->f[ifp_no].datalen = ifp_len;
+               s->f[ifp_no].data = (uint8_t *) ifp;
+               s->f[ifp_no].offset = 0;
+               s->f[ifp_no].src = "UDPTL";
+               if (ifp_no > 0) {
+                       s->f[ifp_no].prev = &s->f[ifp_no - 1];
+                       s->f[ifp_no - 1].next = &s->f[ifp_no];
+               }
+               s->f[ifp_no].next = NULL;
+       }
+
+       s->rx_seq_no = seq_no + 1;
+       return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, uint8_t *ifp, int ifp_len)
+{
+       uint8_t fec[LOCAL_FAX_MAX_DATAGRAM];
+       int i;
+       int j;
+       int seq;
+       int entry;
+       int entries;
+       int span;
+       int m;
+       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(buf, &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(buf, &len, s->tx[j].buf, s->tx[j].buf_len) < 0)
+                               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(buf, &len, fec, high_tide) < 0)
+                               return -1;
+               }
+               break;
+       }
+
+       if (s->verbose)
+               fprintf(stderr, "\n");
+
+       s->tx_seq_no++;
+       return len;
+}
+
+int ast_udptl_fd(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 sockaddr_in sin;
+       socklen_t len;
+       uint16_t seqno = 0;
+       char iabuf[INET_ADDRSTRLEN];
+       uint16_t *udptlheader;
+       static struct ast_frame null_frame = { AST_FRAME_NULL, };
+
+       len = sizeof(sin);
+       
+       /* Cache where the header will go */
+       res = recvfrom(udptl->fd,
+                       udptl->rawdata + AST_FRIENDLY_OFFSET,
+                       sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET,
+                       0,
+                       (struct sockaddr *) &sin,
+                       &len);
+       udptlheader = (uint16_t *)(udptl->rawdata + AST_FRIENDLY_OFFSET);
+       if (res < 0) {
+               if (errno != EAGAIN)
+                       ast_log(LOG_WARNING, "UDPTL read error: %s\n", strerror(errno));
+               if (errno == EBADF)
+                       CRASH;
+               return &null_frame;
+       }
+
+       /* Ignore if the other side hasn't been given an address yet. */
+       if (!udptl->them.sin_addr.s_addr || !udptl->them.sin_port)
+               return &null_frame;
+
+       if (udptl->nat) {
+               /* Send to whoever sent to us */
+               if ((udptl->them.sin_addr.s_addr != sin.sin_addr.s_addr) ||
+                       (udptl->them.sin_port != sin.sin_port)) {
+                       memcpy(&udptl->them, &sin, sizeof(udptl->them));
+                       ast_log(LOG_DEBUG, "UDPTL NAT: Using address %s:%d\n", ast_inet_ntoa(iabuf, sizeof(iabuf), udptl->them.sin_addr), ntohs(udptl->them.sin_port));
+               }
+       }
+
+       if (udptl_debug_test_addr(&sin)) {
+               ast_verbose("Got UDPTL packet from %s:%d (type %d, seq %d, len %d)\n",
+                       ast_inet_ntoa(iabuf, sizeof(iabuf), sin.sin_addr), ntohs(sin.sin_port), 0, seqno, res);
+       }
+#if 0
+       printf("Got UDPTL packet from %s:%d (seq %d, len = %d)\n", ast_inet_ntoa(iabuf, sizeof(iabuf), sin.sin_addr), ntohs(sin.sin_port), seqno, res);
+#endif
+       udptl_rx_packet(udptl, udptl->rawdata + AST_FRIENDLY_OFFSET, res);
+
+       return &udptl->f[0];
+}
+
+void ast_udptl_offered_from_local(struct ast_udptl* udptl, int local)
+{
+       if (udptl)
+               udptl->udptl_offered_from_local = local;
+       else
+               ast_log(LOG_WARNING, "udptl structure is null\n");
+}
+
+int ast_udptl_get_error_correction_scheme(struct ast_udptl* udptl)
+{
+    if (udptl)
+           return udptl->error_correction_scheme;
+    else {
+           ast_log(LOG_WARNING, "udptl structure is null\n");
+           return -1;
+    }
+}
+
+void ast_udptl_set_error_correction_scheme(struct ast_udptl* udptl, int ec)
+{
+    if (udptl) {
+       switch (ec) {
+           case UDPTL_ERROR_CORRECTION_FEC:
+               udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
+               break;
+           case UDPTL_ERROR_CORRECTION_REDUNDANCY:
+               udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
+               break;
+           case UDPTL_ERROR_CORRECTION_NONE:
+               udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_NONE;
+               break;
+           default:
+               ast_log(LOG_WARNING, "error correction parameter invalid");
+       };
+    } else
+           ast_log(LOG_WARNING, "udptl structure is null\n");
+}
+
+int ast_udptl_get_local_max_datagram(struct ast_udptl* udptl)
+{
+    if (udptl)
+           return udptl->local_max_datagram_size;
+    else {
+           ast_log(LOG_WARNING, "udptl structure is null\n");
+           return -1;
+    }
+}
+
+int ast_udptl_get_far_max_datagram(struct ast_udptl* udptl)
+{
+    if (udptl)
+           return udptl->far_max_datagram_size;
+    else {
+           ast_log(LOG_WARNING, "udptl structure is null\n");
+           return -1;
+    }
+}
+
+void ast_udptl_set_local_max_datagram(struct ast_udptl* udptl, int max_datagram)
+{
+    if (udptl)
+           udptl->local_max_datagram_size = max_datagram;
+    else
+           ast_log(LOG_WARNING, "udptl structure is null\n");
+}
+
+void ast_udptl_set_far_max_datagram(struct ast_udptl* udptl, int max_datagram)
+{
+    if (udptl)
+           udptl->far_max_datagram_size = max_datagram;
+    else
+           ast_log(LOG_WARNING, "udptl structure is null\n");
+}
+
+struct ast_udptl *ast_udptl_new_with_bindaddr(struct sched_context *sched, struct io_context *io, int callbackmode, struct in_addr addr)
+{
+       struct ast_udptl *udptl;
+       int x;
+       int startplace;
+       int i;
+       long int flags;
+
+       if ((udptl = malloc(sizeof(struct ast_udptl))) == NULL)
+               return NULL;
+       memset(udptl, 0, sizeof(struct ast_udptl));
+
+       if (udptlfectype == 2)
+               udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
+       else if (udptlfectype == 1)
+               udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
+       else
+               udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_NONE;
+       udptl->error_correction_span = udptlfecspan;
+       udptl->error_correction_entries = udptlfecentries;
+       
+       udptl->far_max_datagram_size = udptlmaxdatagram;
+       udptl->local_max_datagram_size = udptlmaxdatagram;
+
+       memset(&udptl->rx, 0, sizeof(udptl->rx));
+       memset(&udptl->tx, 0, sizeof(udptl->tx));
+       for (i = 0;  i <= UDPTL_BUF_MASK;  i++) {
+               udptl->rx[i].buf_len = -1;
+               udptl->tx[i].buf_len = -1;
+       }
+
+       udptl->seqno = rand() & 0xffff;
+       udptl->them.sin_family = AF_INET;
+       udptl->us.sin_family = AF_INET;
+
+       if ((udptl->fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+               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 = (rand()%(udptlend - udptlstart)) + udptlstart;
+       startplace = x;
+       for (;;) {
+               udptl->us.sin_port = htons(x);
+               udptl->us.sin_addr = addr;
+               if (bind(udptl->fd, (struct sockaddr *) &udptl->us, sizeof(udptl->us)) == 0)
+                       break;
+               if (errno != EADDRINUSE) {
+                       ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno));
+                       close(udptl->fd);
+                       free(udptl);
+                       return NULL;
+               }
+               if (++x > udptlend)
+                       x = udptlstart;
+               if (x == startplace) {
+                       ast_log(LOG_WARNING, "No UDPTL ports remaining\n");
+                       close(udptl->fd);
+                       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;
+}
+
+struct ast_udptl *ast_udptl_new(struct sched_context *sched, struct io_context *io, int callbackmode)
+{
+       struct in_addr ia;
+       memset(&ia, 0, sizeof(ia));
+       return ast_udptl_new_with_bindaddr(sched, io, callbackmode, ia);
+}
+
+int ast_udptl_settos(struct ast_udptl *udptl, int tos)
+{
+       int res;
+
+       if ((res = setsockopt(udptl->fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)))) 
+               ast_log(LOG_WARNING, "UDPTL unable to set TOS to %d\n", tos);
+       return res;
+}
+
+void ast_udptl_set_peer(struct ast_udptl *udptl, struct sockaddr_in *them)
+{
+       udptl->them.sin_port = them->sin_port;
+       udptl->them.sin_addr = them->sin_addr;
+}
+
+void ast_udptl_get_peer(struct ast_udptl *udptl, struct sockaddr_in *them)
+{
+       them->sin_family = AF_INET;
+       them->sin_port = udptl->them.sin_port;
+       them->sin_addr = udptl->them.sin_addr;
+}
+
+void ast_udptl_get_us(struct ast_udptl *udptl, struct sockaddr_in *us)
+{
+       memcpy(us, &udptl->us, sizeof(udptl->us));
+}
+
+void ast_udptl_stop(struct ast_udptl *udptl)
+{
+       memset(&udptl->them.sin_addr, 0, sizeof(udptl->them.sin_addr));
+       memset(&udptl->them.sin_port, 0, sizeof(udptl->them.sin_port));
+}
+
+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);
+       free(udptl);
+}
+
+int ast_udptl_write(struct ast_udptl *s, struct ast_frame *f)
+{
+       int len;
+       int res;
+       uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
+       char iabuf[INET_ADDRSTRLEN];
+
+       /* If we have no peer, return immediately */    
+       if (s->them.sin_addr.s_addr == INADDR_ANY)
+               return 0;
+
+       /* If there is no data length, return immediately */
+       if (f->datalen == 0)
+               return 0;
+       
+       if (f->frametype != AST_FRAME_MODEM) {
+               ast_log(LOG_WARNING, "UDPTL can only send T.38 data\n");
+               return -1;
+       }
+
+       /* Cook up the UDPTL packet, with the relevant EC info. */
+       len = udptl_build_packet(s, buf, f->data, f->datalen);
+
+       if (len > 0  &&  s->them.sin_port && s->them.sin_addr.s_addr) {
+               if ((res = sendto(s->fd, buf, len, 0, (struct sockaddr *) &s->them, sizeof(s->them))) < 0)
+                       ast_log(LOG_NOTICE, "UDPTL Transmission error to %s:%d: %s\n", ast_inet_ntoa(iabuf, sizeof(iabuf), s->them.sin_addr), ntohs(s->them.sin_port), strerror(errno));
+#if 0
+               printf("Sent %d bytes of UDPTL data to %s:%d\n", res, ast_inet_ntoa(iabuf, sizeof(iabuf), udptl->them.sin_addr), ntohs(udptl->them.sin_port));
+#endif
+               if (udptl_debug_test_addr(&s->them))
+                       ast_verbose("Sent UDPTL packet to %s:%d (type %d, seq %d, len %d)\n",
+                                       ast_inet_ntoa(iabuf, sizeof(iabuf), s->them.sin_addr),
+                                       ntohs(s->them.sin_port), 0, s->seqno, len);
+       }
+               
+       return 0;
+}
+
+void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto)
+{
+       struct ast_udptl_protocol *cur;
+       struct ast_udptl_protocol *prev;
+
+       cur = protos;
+       prev = NULL;
+       while(cur) {
+               if (cur == proto) {
+                       if (prev)
+                               prev->next = proto->next;
+                       else
+                               protos = proto->next;
+                       return;
+               }
+               prev = cur;
+               cur = cur->next;
+       }
+}
+
+int ast_udptl_proto_register(struct ast_udptl_protocol *proto)
+{
+       struct ast_udptl_protocol *cur;
+
+       cur = protos;
+       while(cur) {
+               if (cur->type == proto->type) {
+                       ast_log(LOG_WARNING, "Tried to register same protocol '%s' twice\n", cur->type);
+                       return -1;
+               }
+               cur = cur->next;
+       }
+       proto->next = protos;
+       protos = proto;
+       return 0;
+}
+
+static struct ast_udptl_protocol *get_proto(struct ast_channel *chan)
+{
+       struct ast_udptl_protocol *cur;
+
+       cur = protos;
+       while (cur) {
+               if (cur->type == chan->type)
+                       return cur;
+               cur = cur->next;
+       }
+       return NULL;
+}
+
+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 sockaddr_in ac0;
+       struct sockaddr_in ac1;
+       struct sockaddr_in t0;
+       struct sockaddr_in t1;
+       char iabuf[INET_ADDRSTRLEN];
+       void *pvt0;
+       void *pvt1;
+       int to;
+       
+       ast_mutex_lock(&c0->lock);
+       while (ast_mutex_trylock(&c1->lock)) {
+               ast_mutex_unlock(&c0->lock);
+               usleep(1);
+               ast_mutex_lock(&c0->lock);
+       }
+       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_mutex_unlock(&c0->lock);
+               ast_mutex_unlock(&c1->lock);
+               return -1;
+       }
+       if (!pr1) {
+               ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c1->name);
+               ast_mutex_unlock(&c0->lock);
+               ast_mutex_unlock(&c1->lock);
+               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_mutex_unlock(&c0->lock);
+               ast_mutex_unlock(&c1->lock);
+               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);
+       } 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);
+       else {
+               /* Store UDPTL peer */
+               ast_udptl_get_peer(p0, &ac0);
+       }
+       ast_mutex_unlock(&c0->lock);
+       ast_mutex_unlock(&c1->lock);
+       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_log(LOG_DEBUG, "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 (inaddrcmp(&t1, &ac1)) {
+                       ast_log(LOG_DEBUG, "Oooh, '%s' changed end address to %s:%d\n", 
+                               c1->name, ast_inet_ntoa(iabuf, sizeof(iabuf), t1.sin_addr), ntohs(t1.sin_port));
+                       ast_log(LOG_DEBUG, "Oooh, '%s' was %s:%d\n", 
+                               c1->name, ast_inet_ntoa(iabuf, sizeof(iabuf), ac1.sin_addr), ntohs(ac1.sin_port));
+                       memcpy(&ac1, &t1, sizeof(ac1));
+               }
+               if (inaddrcmp(&t0, &ac0)) {
+                       ast_log(LOG_DEBUG, "Oooh, '%s' changed end address to %s:%d\n", 
+                               c0->name, ast_inet_ntoa(iabuf, sizeof(iabuf), t0.sin_addr), ntohs(t0.sin_port));
+                       ast_log(LOG_DEBUG, "Oooh, '%s' was %s:%d\n", 
+                               c0->name, ast_inet_ntoa(iabuf, sizeof(iabuf), ac0.sin_addr), ntohs(ac0.sin_port));
+                       memcpy(&ac0, &t0, sizeof(ac0));
+               }
+               who = ast_waitfor_n(cs, 2, &to);
+               if (!who) {
+                       ast_log(LOG_DEBUG, "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_log(LOG_DEBUG, "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 int udptl_do_debug_ip(int fd, int argc, char *argv[])
+{
+       struct hostent *hp;
+       struct ast_hostent ahp;
+       char iabuf[INET_ADDRSTRLEN];
+       int port;
+       char *p;
+       char *arg;
+
+       port = 0;
+       if (argc != 4)
+               return RESULT_SHOWUSAGE;
+       arg = argv[3];
+       p = strstr(arg, ":");
+       if (p) {
+               *p = '\0';
+               p++;
+               port = atoi(p);
+       }
+       hp = ast_gethostbyname(arg, &ahp);
+       if (hp == NULL)
+               return RESULT_SHOWUSAGE;
+       udptldebugaddr.sin_family = AF_INET;
+       memcpy(&udptldebugaddr.sin_addr, hp->h_addr, sizeof(udptldebugaddr.sin_addr));
+       udptldebugaddr.sin_port = htons(port);
+       if (port == 0)
+               ast_cli(fd, "UDPTL Debugging Enabled for IP: %s\n", ast_inet_ntoa(iabuf, sizeof(iabuf), udptldebugaddr.sin_addr));
+       else
+               ast_cli(fd, "UDPTL Debugging Enabled for IP: %s:%d\n", ast_inet_ntoa(iabuf, sizeof(iabuf), udptldebugaddr.sin_addr), port);
+       udptldebug = 1;
+       return RESULT_SUCCESS;
+}
+
+static int udptl_do_debug(int fd, int argc, char *argv[])
+{
+       if (argc != 2) {
+               if (argc != 4)
+                       return RESULT_SHOWUSAGE;
+               return udptl_do_debug_ip(fd, argc, argv);
+       }
+       udptldebug = 1;
+       memset(&udptldebugaddr,0,sizeof(udptldebugaddr));
+       ast_cli(fd, "UDPTL Debugging Enabled\n");
+       return RESULT_SUCCESS;
+}
+   
+static int udptl_no_debug(int fd, int argc, char *argv[])
+{
+       if (argc !=3)
+               return RESULT_SHOWUSAGE;
+       udptldebug = 0;
+       ast_cli(fd,"UDPTL Debugging Disabled\n");
+       return RESULT_SUCCESS;
+}
+
+static char debug_usage[] =
+  "Usage: udptl debug [ip host[:port]]\n"
+  "       Enable dumping of all UDPTL packets to and from host.\n";
+
+static char no_debug_usage[] =
+  "Usage: udptl no debug\n"
+  "       Disable all UDPTL debugging\n";
+
+static struct ast_cli_entry  cli_debug_ip =
+{{ "udptl", "debug", "ip", NULL } , udptl_do_debug, "Enable UDPTL debugging on IP", debug_usage };
+
+static struct ast_cli_entry  cli_debug =
+{{ "udptl", "debug", NULL } , udptl_do_debug, "Enable UDPTL debugging", debug_usage };
+
+static struct ast_cli_entry  cli_no_debug =
+{{ "udptl", "no", "debug", NULL } , udptl_no_debug, "Disable UDPTL debugging", no_debug_usage };
+
+void ast_udptl_reload(void)
+{
+       struct ast_config *cfg;
+       char *s;
+
+       udptlstart = 4500;
+       udptlend = 4999;
+       udptlfectype = 0;
+       udptlfecentries = 0;
+       udptlfecspan = 0;
+       udptlmaxdatagram = 0;
+
+       if ((cfg = ast_config_load("udptl.conf"))) {
+               if ((s = ast_variable_retrieve(cfg, "general", "udptlstart"))) {
+                       udptlstart = atoi(s);
+                       if (udptlstart < 1024)
+                               udptlstart = 1024;
+                       if (udptlstart > 65535)
+                               udptlstart = 65535;
+               }
+               if ((s = ast_variable_retrieve(cfg, "general", "udptlend"))) {
+                       udptlend = atoi(s);
+                       if (udptlend < 1024)
+                               udptlend = 1024;
+                       if (udptlend > 65535)
+                               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"))) {
+                       if (strcmp(s, "t38UDPFEC") == 0)
+                               udptlfectype = 2;
+                       else if (strcmp(s, "t38UDPRedundancy") == 0)
+                               udptlfectype = 1;
+               }
+               if ((s = ast_variable_retrieve(cfg, "general", "T38FaxMaxDatagram"))) {
+                       udptlmaxdatagram = atoi(s);
+                       if (udptlmaxdatagram < 0)
+                               udptlmaxdatagram = 0;
+                       if (udptlmaxdatagram > LOCAL_FAX_MAX_DATAGRAM)
+                               udptlmaxdatagram = LOCAL_FAX_MAX_DATAGRAM;
+               }
+               if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECentries"))) {
+                       udptlfecentries = atoi(s);
+                       if (udptlfecentries < 0)
+                               udptlfecentries = 0;
+                       if (udptlfecentries > MAX_FEC_ENTRIES)
+                               udptlfecentries = MAX_FEC_ENTRIES;
+               }
+               if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECspan"))) {
+                       udptlfecspan = atoi(s);
+                       if (udptlfecspan < 0)
+                               udptlfecspan = 0;
+                       if (udptlfecspan > MAX_FEC_SPAN)
+                               udptlfecspan = MAX_FEC_SPAN;
+               }
+               ast_config_destroy(cfg);
+       }
+       if (udptlstart >= udptlend) {
+               ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end\n");
+               udptlstart = 4500;
+               udptlend = 4999;
+       }
+       if (option_verbose > 1)
+               ast_verbose(VERBOSE_PREFIX_2 "UDPTL allocating from port range %d -> %d\n", udptlstart, udptlend);
+}
+
+void ast_udptl_init(void)
+{
+       ast_cli_register(&cli_debug);
+       ast_cli_register(&cli_debug_ip);
+       ast_cli_register(&cli_no_debug);
+       ast_udptl_reload();
+}