Fri Aug 24 02:22:17 2007

Asterisk developer's documentation


udptl.c

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00001 /*
00002  * Asterisk -- A telephony toolkit for Linux.
00003  *
00004  * UDPTL support for T.38
00005  * 
00006  * Copyright (C) 2005, Steve Underwood, partly based on RTP code which is
00007  * Copyright (C) 1999-2006, Digium, Inc.
00008  *
00009  * Steve Underwood <steveu@coppice.org>
00010  *
00011  * See http://www.asterisk.org for more information about
00012  * the Asterisk project. Please do not directly contact
00013  * any of the maintainers of this project for assistance;
00014  * the project provides a web site, mailing lists and IRC
00015  * channels for your use.
00016  *
00017  * This program is free software, distributed under the terms of
00018  * the GNU General Public License Version 2. See the LICENSE file
00019  * at the top of the source tree.
00020  *
00021  * A license has been granted to Digium (via disclaimer) for the use of
00022  * this code.
00023  */
00024 
00025 /*! 
00026  * \file 
00027  *
00028  * \brief UDPTL support for T.38 faxing
00029  * 
00030  *
00031  * \author Mark Spencer <markster@digium.com>,  Steve Underwood <steveu@coppice.org>
00032  * 
00033  * \page T38fax_udptl T38 fax passhtrough :: UDPTL
00034  *
00035  * Asterisk supports T.38 fax passthrough. Asterisk will not be a client, server
00036  * or any form of gateway. Currently fax passthrough is only implemented in the
00037  * SIP channel for strict SIP to SIP calls. If you are using chan_local or chan_agent
00038  * as a proxy channel, T.38 passthrough will not work.
00039  *
00040  * UDPTL is handled very much like RTP. It can be reinvited to go directly between
00041  * the endpoints, without involving Asterisk in the media stream.
00042  * 
00043  * \b References:
00044  * - chan_sip.c
00045  * - udptl.c
00046  */
00047 
00048 
00049 #include "asterisk.h"
00050 
00051 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
00052 
00053 #include <stdio.h>
00054 #include <stdlib.h>
00055 #include <string.h>
00056 #include <sys/time.h>
00057 #include <signal.h>
00058 #include <errno.h>
00059 #include <unistd.h>
00060 #include <netinet/in.h>
00061 #include <sys/time.h>
00062 #include <sys/socket.h>
00063 #include <arpa/inet.h>
00064 #include <fcntl.h>
00065 
00066 #include "asterisk/udptl.h"
00067 #include "asterisk/frame.h"
00068 #include "asterisk/logger.h"
00069 #include "asterisk/options.h"
00070 #include "asterisk/channel.h"
00071 #include "asterisk/acl.h"
00072 #include "asterisk/channel.h"
00073 #include "asterisk/config.h"
00074 #include "asterisk/lock.h"
00075 #include "asterisk/utils.h"
00076 #include "asterisk/cli.h"
00077 #include "asterisk/unaligned.h"
00078 #include "asterisk/utils.h"
00079 
00080 #define UDPTL_MTU    1200
00081 
00082 #if !defined(FALSE)
00083 #define FALSE 0
00084 #endif
00085 #if !defined(TRUE)
00086 #define TRUE (!FALSE)
00087 #endif
00088 
00089 static int udptlstart;
00090 static int udptlend;
00091 static int udptldebug;                      /*!< Are we debugging? */
00092 static struct sockaddr_in udptldebugaddr;   /*!< Debug packets to/from this host */
00093 #ifdef SO_NO_CHECK
00094 static int nochecksums;
00095 #endif
00096 static int udptlfectype;
00097 static int udptlfecentries;
00098 static int udptlfecspan;
00099 static int udptlmaxdatagram;
00100 
00101 #define LOCAL_FAX_MAX_DATAGRAM      400
00102 #define MAX_FEC_ENTRIES             5
00103 #define MAX_FEC_SPAN                5
00104 
00105 #define UDPTL_BUF_MASK              15
00106 
00107 typedef struct {
00108    int buf_len;
00109    uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
00110 } udptl_fec_tx_buffer_t;
00111 
00112 typedef struct {
00113    int buf_len;
00114    uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
00115    int fec_len[MAX_FEC_ENTRIES];
00116    uint8_t fec[MAX_FEC_ENTRIES][LOCAL_FAX_MAX_DATAGRAM];
00117    int fec_span;
00118    int fec_entries;
00119 } udptl_fec_rx_buffer_t;
00120 
00121 /*! \brief Structure for an UDPTL session */
00122 struct ast_udptl {
00123    int fd;
00124    char resp;
00125    struct ast_frame f[16];
00126    unsigned char rawdata[8192 + AST_FRIENDLY_OFFSET];
00127    unsigned int lasteventseqn;
00128    int nat;
00129    int flags;
00130    struct sockaddr_in us;
00131    struct sockaddr_in them;
00132    int *ioid;
00133    uint16_t seqno;
00134    struct sched_context *sched;
00135    struct io_context *io;
00136    void *data;
00137    ast_udptl_callback callback;
00138    int udptl_offered_from_local;
00139 
00140    /*! This option indicates the error correction scheme used in transmitted UDPTL
00141        packets. */
00142    int error_correction_scheme;
00143 
00144    /*! This option indicates the number of error correction entries transmitted in
00145        UDPTL packets. */
00146    int error_correction_entries;
00147 
00148    /*! This option indicates the span of the error correction entries in transmitted
00149        UDPTL packets (FEC only). */
00150    int error_correction_span;
00151 
00152    /*! This option indicates the maximum size of a UDPTL packet that can be accepted by
00153        the remote device. */
00154    int far_max_datagram_size;
00155 
00156    /*! This option indicates the maximum size of a UDPTL packet that we are prepared to
00157        accept. */
00158    int local_max_datagram_size;
00159 
00160    int verbose;
00161 
00162    struct sockaddr_in far;
00163 
00164    int tx_seq_no;
00165    int rx_seq_no;
00166    int rx_expected_seq_no;
00167 
00168    udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1];
00169    udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1];
00170 };
00171 
00172 static struct ast_udptl_protocol *protos;
00173 
00174 static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, int len);
00175 static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, uint8_t *ifp, int ifp_len);
00176 
00177 static inline int udptl_debug_test_addr(struct sockaddr_in *addr)
00178 {
00179    if (udptldebug == 0)
00180       return 0;
00181    if (udptldebugaddr.sin_addr.s_addr) {
00182       if (((ntohs(udptldebugaddr.sin_port) != 0)
00183          && (udptldebugaddr.sin_port != addr->sin_port))
00184          || (udptldebugaddr.sin_addr.s_addr != addr->sin_addr.s_addr))
00185          return 0;
00186    }
00187    return 1;
00188 }
00189 
00190 static int decode_length(uint8_t *buf, int limit, int *len, int *pvalue)
00191 {
00192    if ((buf[*len] & 0x80) == 0) {
00193       if (*len >= limit)
00194          return -1;
00195       *pvalue = buf[*len];
00196       (*len)++;
00197       return 0;
00198    }
00199    if ((buf[*len] & 0x40) == 0) {
00200       if (*len >= limit - 1)
00201          return -1;
00202       *pvalue = (buf[*len] & 0x3F) << 8;
00203       (*len)++;
00204       *pvalue |= buf[*len];
00205       (*len)++;
00206       return 0;
00207    }
00208    if (*len >= limit)
00209       return -1;
00210    *pvalue = (buf[*len] & 0x3F) << 14;
00211    (*len)++;
00212    /* Indicate we have a fragment */
00213    return 1;
00214 }
00215 /*- End of function --------------------------------------------------------*/
00216 
00217 static int decode_open_type(uint8_t *buf, int limit, int *len, const uint8_t **p_object, int *p_num_octets)
00218 {
00219    int octet_cnt;
00220    int octet_idx;
00221    int stat;
00222    int i;
00223    const uint8_t **pbuf;
00224 
00225    for (octet_idx = 0, *p_num_octets = 0; ; octet_idx += octet_cnt) {
00226       if ((stat = decode_length(buf, limit, len, &octet_cnt)) < 0)
00227          return -1;
00228       if (octet_cnt > 0) {
00229          *p_num_octets += octet_cnt;
00230 
00231          pbuf = &p_object[octet_idx];
00232          i = 0;
00233          /* Make sure the buffer contains at least the number of bits requested */
00234          if ((*len + octet_cnt) > limit)
00235             return -1;
00236 
00237          *pbuf = &buf[*len];
00238          *len += octet_cnt;
00239       }
00240       if (stat == 0)
00241          break;
00242    }
00243    return 0;
00244 }
00245 /*- End of function --------------------------------------------------------*/
00246 
00247 static int encode_length(uint8_t *buf, int *len, int value)
00248 {
00249    int multiplier;
00250 
00251    if (value < 0x80) {
00252       /* 1 octet */
00253       buf[*len] = value;
00254       (*len)++;
00255       return value;
00256    }
00257    if (value < 0x4000) {
00258       /* 2 octets */
00259       /* Set the first bit of the first octet */
00260       buf[*len] = ((0x8000 | value) >> 8) & 0xFF;
00261       (*len)++;
00262       buf[*len] = value & 0xFF;
00263       (*len)++;
00264       return value;
00265    }
00266    /* Fragmentation */
00267    multiplier = (value < 0x10000) ? (value >> 14) : 4;
00268    /* Set the first 2 bits of the octet */
00269    buf[*len] = 0xC0 | multiplier;
00270    (*len)++;
00271    return multiplier << 14;
00272 }
00273 /*- End of function --------------------------------------------------------*/
00274 
00275 static int encode_open_type(uint8_t *buf, int *len, const uint8_t *data, int num_octets)
00276 {
00277    int enclen;
00278    int octet_idx;
00279    uint8_t zero_byte;
00280 
00281    /* If open type is of zero length, add a single zero byte (10.1) */
00282    if (num_octets == 0) {
00283       zero_byte = 0;
00284       data = &zero_byte;
00285       num_octets = 1;
00286    }
00287    /* Encode the open type */
00288    for (octet_idx = 0; ; num_octets -= enclen, octet_idx += enclen) {
00289       if ((enclen = encode_length(buf, len, num_octets)) < 0)
00290          return -1;
00291       if (enclen > 0) {
00292          memcpy(&buf[*len], &data[octet_idx], enclen);
00293          *len += enclen;
00294       }
00295       if (enclen >= num_octets)
00296          break;
00297    }
00298 
00299    return 0;
00300 }
00301 /*- End of function --------------------------------------------------------*/
00302 
00303 static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, int len)
00304 {
00305    int stat;
00306    int stat2;
00307    int i;
00308    int j;
00309    int k;
00310    int l;
00311    int m;
00312    int x;
00313    int limit;
00314    int which;
00315    int ptr;
00316    int count;
00317    int total_count;
00318    int seq_no;
00319    const uint8_t *ifp;
00320    const uint8_t *data;
00321    int ifp_len;
00322    int repaired[16];
00323    const uint8_t *bufs[16];
00324    int lengths[16];
00325    int span;
00326    int entries;
00327    int ifp_no;
00328 
00329    ptr = 0;
00330    ifp_no = 0;
00331    memset(&s->f[0], 0, sizeof(s->f[0]));
00332 
00333    /* Decode seq_number */
00334    if (ptr + 2 > len)
00335       return -1;
00336    seq_no = (buf[0] << 8) | buf[1];
00337    ptr += 2;
00338 
00339    /* Break out the primary packet */
00340    if ((stat = decode_open_type(buf, len, &ptr, &ifp, &ifp_len)) != 0)
00341       return -1;
00342    /* Decode error_recovery */
00343    if (ptr + 1 > len)
00344       return -1;
00345    if ((buf[ptr++] & 0x80) == 0) {
00346       /* Secondary packet mode for error recovery */
00347       if (seq_no > s->rx_seq_no) {
00348          /* We received a later packet than we expected, so we need to check if we can fill in the gap from the
00349             secondary packets. */
00350          total_count = 0;
00351          do {
00352             if ((stat2 = decode_length(buf, len, &ptr, &count)) < 0)
00353                return -1;
00354             for (i = 0; i < count; i++) {
00355                if ((stat = decode_open_type(buf, len, &ptr, &bufs[total_count + i], &lengths[total_count + i])) != 0)
00356                   return -1;
00357             }
00358             total_count += count;
00359          }
00360          while (stat2 > 0);
00361          /* Step through in reverse order, so we go oldest to newest */
00362          for (i = total_count; i > 0; i--) {
00363             if (seq_no - i >= s->rx_seq_no) {
00364                /* This one wasn't seen before */
00365                /* Decode the secondary IFP packet */
00366                //fprintf(stderr, "Secondary %d, len %d\n", seq_no - i, lengths[i - 1]);
00367                s->f[ifp_no].frametype = AST_FRAME_MODEM;
00368                s->f[ifp_no].subclass = AST_MODEM_T38;
00369 
00370                s->f[ifp_no].mallocd = 0;
00371                //s->f[ifp_no].???seq_no = seq_no - i;
00372                s->f[ifp_no].datalen = lengths[i - 1];
00373                s->f[ifp_no].data = (uint8_t *) bufs[i - 1];
00374                s->f[ifp_no].offset = 0;
00375                s->f[ifp_no].src = "UDPTL";
00376                if (ifp_no > 0)
00377                   AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00378                AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00379                ifp_no++;
00380             }
00381          }
00382       }
00383       /* If packets are received out of sequence, we may have already processed this packet from the error
00384          recovery information in a packet already received. */
00385       if (seq_no >= s->rx_seq_no) {
00386          /* Decode the primary IFP packet */
00387          s->f[ifp_no].frametype = AST_FRAME_MODEM;
00388          s->f[ifp_no].subclass = AST_MODEM_T38;
00389          
00390          s->f[ifp_no].mallocd = 0;
00391          //s->f[ifp_no].???seq_no = seq_no;
00392          s->f[ifp_no].datalen = ifp_len;
00393          s->f[ifp_no].data = (uint8_t *) ifp;
00394          s->f[ifp_no].offset = 0;
00395          s->f[ifp_no].src = "UDPTL";
00396          if (ifp_no > 0)
00397             AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00398          AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00399       }
00400    }
00401    else
00402    {
00403       /* FEC mode for error recovery */
00404       /* Our buffers cannot tolerate overlength IFP packets in FEC mode */
00405       if (ifp_len > LOCAL_FAX_MAX_DATAGRAM)
00406          return -1;
00407       /* Update any missed slots in the buffer */
00408       for ( ; seq_no > s->rx_seq_no; s->rx_seq_no++) {
00409          x = s->rx_seq_no & UDPTL_BUF_MASK;
00410          s->rx[x].buf_len = -1;
00411          s->rx[x].fec_len[0] = 0;
00412          s->rx[x].fec_span = 0;
00413          s->rx[x].fec_entries = 0;
00414       }
00415 
00416       x = seq_no & UDPTL_BUF_MASK;
00417 
00418       memset(repaired, 0, sizeof(repaired));
00419 
00420       /* Save the new IFP packet */
00421       memcpy(s->rx[x].buf, ifp, ifp_len);
00422       s->rx[x].buf_len = ifp_len;
00423       repaired[x] = TRUE;
00424 
00425       /* Decode the FEC packets */
00426       /* The span is defined as an unconstrained integer, but will never be more
00427          than a small value. */
00428       if (ptr + 2 > len)
00429          return -1;
00430       if (buf[ptr++] != 1)
00431          return -1;
00432       span = buf[ptr++];
00433       s->rx[x].fec_span = span;
00434 
00435       /* The number of entries is defined as a length, but will only ever be a small
00436          value. Treat it as such. */
00437       if (ptr + 1 > len)
00438          return -1;
00439       entries = buf[ptr++];
00440       s->rx[x].fec_entries = entries;
00441 
00442       /* Decode the elements */
00443       for (i = 0; i < entries; i++) {
00444          if ((stat = decode_open_type(buf, len, &ptr, &data, &s->rx[x].fec_len[i])) != 0)
00445             return -1;
00446          if (s->rx[x].fec_len[i] > LOCAL_FAX_MAX_DATAGRAM)
00447             return -1;
00448 
00449          /* Save the new FEC data */
00450          memcpy(s->rx[x].fec[i], data, s->rx[x].fec_len[i]);
00451 #if 0
00452          fprintf(stderr, "FEC: ");
00453          for (j = 0; j < s->rx[x].fec_len[i]; j++)
00454             fprintf(stderr, "%02X ", data[j]);
00455          fprintf(stderr, "\n");
00456 #endif
00457       }
00458 
00459       /* See if we can reconstruct anything which is missing */
00460       /* TODO: this does not comprehensively hunt back and repair everything that is possible */
00461       for (l = x; l != ((x - (16 - span*entries)) & UDPTL_BUF_MASK); l = (l - 1) & UDPTL_BUF_MASK) {
00462          if (s->rx[l].fec_len[0] <= 0)
00463             continue;
00464          for (m = 0; m < s->rx[l].fec_entries; m++) {
00465             limit = (l + m) & UDPTL_BUF_MASK;
00466             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) {
00467                if (s->rx[k].buf_len <= 0)
00468                   which = (which == -1) ? k : -2;
00469             }
00470             if (which >= 0) {
00471                /* Repairable */
00472                for (j = 0; j < s->rx[l].fec_len[m]; j++) {
00473                   s->rx[which].buf[j] = s->rx[l].fec[m][j];
00474                   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)
00475                      s->rx[which].buf[j] ^= (s->rx[k].buf_len > j) ? s->rx[k].buf[j] : 0;
00476                }
00477                s->rx[which].buf_len = s->rx[l].fec_len[m];
00478                repaired[which] = TRUE;
00479             }
00480          }
00481       }
00482       /* Now play any new packets forwards in time */
00483       for (l = (x + 1) & UDPTL_BUF_MASK, j = seq_no - UDPTL_BUF_MASK; l != x; l = (l + 1) & UDPTL_BUF_MASK, j++) {
00484          if (repaired[l]) {
00485             //fprintf(stderr, "Fixed packet %d, len %d\n", j, l);
00486             s->f[ifp_no].frametype = AST_FRAME_MODEM;
00487             s->f[ifp_no].subclass = AST_MODEM_T38;
00488          
00489             s->f[ifp_no].mallocd = 0;
00490             //s->f[ifp_no].???seq_no = j;
00491             s->f[ifp_no].datalen = s->rx[l].buf_len;
00492             s->f[ifp_no].data = s->rx[l].buf;
00493             s->f[ifp_no].offset = 0;
00494             s->f[ifp_no].src = "UDPTL";
00495             if (ifp_no > 0)
00496                AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00497             AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00498             ifp_no++;
00499          }
00500       }
00501       /* Decode the primary IFP packet */
00502       s->f[ifp_no].frametype = AST_FRAME_MODEM;
00503       s->f[ifp_no].subclass = AST_MODEM_T38;
00504          
00505       s->f[ifp_no].mallocd = 0;
00506       //s->f[ifp_no].???seq_no = j;
00507       s->f[ifp_no].datalen = ifp_len;
00508       s->f[ifp_no].data = (uint8_t *) ifp;
00509       s->f[ifp_no].offset = 0;
00510       s->f[ifp_no].src = "UDPTL";
00511       if (ifp_no > 0)
00512          AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00513       AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00514    }
00515 
00516    s->rx_seq_no = seq_no + 1;
00517    return 0;
00518 }
00519 /*- End of function --------------------------------------------------------*/
00520 
00521 static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, uint8_t *ifp, int ifp_len)
00522 {
00523    uint8_t fec[LOCAL_FAX_MAX_DATAGRAM];
00524    int i;
00525    int j;
00526    int seq;
00527    int entry;
00528    int entries;
00529    int span;
00530    int m;
00531    int len;
00532    int limit;
00533    int high_tide;
00534 
00535    seq = s->tx_seq_no & 0xFFFF;
00536 
00537    /* Map the sequence number to an entry in the circular buffer */
00538    entry = seq & UDPTL_BUF_MASK;
00539 
00540    /* We save the message in a circular buffer, for generating FEC or
00541       redundancy sets later on. */
00542    s->tx[entry].buf_len = ifp_len;
00543    memcpy(s->tx[entry].buf, ifp, ifp_len);
00544    
00545    /* Build the UDPTLPacket */
00546 
00547    len = 0;
00548    /* Encode the sequence number */
00549    buf[len++] = (seq >> 8) & 0xFF;
00550    buf[len++] = seq & 0xFF;
00551 
00552    /* Encode the primary IFP packet */
00553    if (encode_open_type(buf, &len, ifp, ifp_len) < 0)
00554       return -1;
00555 
00556    /* Encode the appropriate type of error recovery information */
00557    switch (s->error_correction_scheme)
00558    {
00559    case UDPTL_ERROR_CORRECTION_NONE:
00560       /* Encode the error recovery type */
00561       buf[len++] = 0x00;
00562       /* The number of entries will always be zero, so it is pointless allowing
00563          for the fragmented case here. */
00564       if (encode_length(buf, &len, 0) < 0)
00565          return -1;
00566       break;
00567    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00568       /* Encode the error recovery type */
00569       buf[len++] = 0x00;
00570       if (s->tx_seq_no > s->error_correction_entries)
00571          entries = s->error_correction_entries;
00572       else
00573          entries = s->tx_seq_no;
00574       /* The number of entries will always be small, so it is pointless allowing
00575          for the fragmented case here. */
00576       if (encode_length(buf, &len, entries) < 0)
00577          return -1;
00578       /* Encode the elements */
00579       for (i = 0; i < entries; i++) {
00580          j = (entry - i - 1) & UDPTL_BUF_MASK;
00581          if (encode_open_type(buf, &len, s->tx[j].buf, s->tx[j].buf_len) < 0)
00582             return -1;
00583       }
00584       break;
00585    case UDPTL_ERROR_CORRECTION_FEC:
00586       span = s->error_correction_span;
00587       entries = s->error_correction_entries;
00588       if (seq < s->error_correction_span*s->error_correction_entries) {
00589          /* In the initial stages, wind up the FEC smoothly */
00590          entries = seq/s->error_correction_span;
00591          if (seq < s->error_correction_span)
00592             span = 0;
00593       }
00594       /* Encode the error recovery type */
00595       buf[len++] = 0x80;
00596       /* Span is defined as an inconstrained integer, which it dumb. It will only
00597          ever be a small value. Treat it as such. */
00598       buf[len++] = 1;
00599       buf[len++] = span;
00600       /* The number of entries is defined as a length, but will only ever be a small
00601          value. Treat it as such. */
00602       buf[len++] = entries;
00603       for (m = 0; m < entries; m++) {
00604          /* Make an XOR'ed entry the maximum length */
00605          limit = (entry + m) & UDPTL_BUF_MASK;
00606          high_tide = 0;
00607          for (i = (limit - span*entries) & UDPTL_BUF_MASK; i != limit; i = (i + entries) & UDPTL_BUF_MASK) {
00608             if (high_tide < s->tx[i].buf_len) {
00609                for (j = 0; j < high_tide; j++)
00610                   fec[j] ^= s->tx[i].buf[j];
00611                for ( ; j < s->tx[i].buf_len; j++)
00612                   fec[j] = s->tx[i].buf[j];
00613                high_tide = s->tx[i].buf_len;
00614             } else {
00615                for (j = 0; j < s->tx[i].buf_len; j++)
00616                   fec[j] ^= s->tx[i].buf[j];
00617             }
00618          }
00619          if (encode_open_type(buf, &len, fec, high_tide) < 0)
00620             return -1;
00621       }
00622       break;
00623    }
00624 
00625    if (s->verbose)
00626       fprintf(stderr, "\n");
00627 
00628    s->tx_seq_no++;
00629    return len;
00630 }
00631 
00632 int ast_udptl_fd(struct ast_udptl *udptl)
00633 {
00634    return udptl->fd;
00635 }
00636 
00637 void ast_udptl_set_data(struct ast_udptl *udptl, void *data)
00638 {
00639    udptl->data = data;
00640 }
00641 
00642 void ast_udptl_set_callback(struct ast_udptl *udptl, ast_udptl_callback callback)
00643 {
00644    udptl->callback = callback;
00645 }
00646 
00647 void ast_udptl_setnat(struct ast_udptl *udptl, int nat)
00648 {
00649    udptl->nat = nat;
00650 }
00651 
00652 static int udptlread(int *id, int fd, short events, void *cbdata)
00653 {
00654    struct ast_udptl *udptl = cbdata;
00655    struct ast_frame *f;
00656 
00657    if ((f = ast_udptl_read(udptl))) {
00658       if (udptl->callback)
00659          udptl->callback(udptl, f, udptl->data);
00660    }
00661    return 1;
00662 }
00663 
00664 struct ast_frame *ast_udptl_read(struct ast_udptl *udptl)
00665 {
00666    int res;
00667    struct sockaddr_in sin;
00668    socklen_t len;
00669    uint16_t seqno = 0;
00670    uint16_t *udptlheader;
00671 
00672    len = sizeof(sin);
00673    
00674    /* Cache where the header will go */
00675    res = recvfrom(udptl->fd,
00676          udptl->rawdata + AST_FRIENDLY_OFFSET,
00677          sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET,
00678          0,
00679          (struct sockaddr *) &sin,
00680          &len);
00681    udptlheader = (uint16_t *)(udptl->rawdata + AST_FRIENDLY_OFFSET);
00682    if (res < 0) {
00683       if (errno != EAGAIN)
00684          ast_log(LOG_WARNING, "UDPTL read error: %s\n", strerror(errno));
00685       if (errno == EBADF)
00686          CRASH;
00687       return &ast_null_frame;
00688    }
00689 
00690    /* Ignore if the other side hasn't been given an address yet. */
00691    if (!udptl->them.sin_addr.s_addr || !udptl->them.sin_port)
00692       return &ast_null_frame;
00693 
00694    if (udptl->nat) {
00695       /* Send to whoever sent to us */
00696       if ((udptl->them.sin_addr.s_addr != sin.sin_addr.s_addr) ||
00697          (udptl->them.sin_port != sin.sin_port)) {
00698          memcpy(&udptl->them, &sin, sizeof(udptl->them));
00699          ast_log(LOG_DEBUG, "UDPTL NAT: Using address %s:%d\n", ast_inet_ntoa(udptl->them.sin_addr), ntohs(udptl->them.sin_port));
00700       }
00701    }
00702 
00703    if (udptl_debug_test_addr(&sin)) {
00704       ast_verbose("Got UDPTL packet from %s:%d (type %d, seq %d, len %d)\n",
00705          ast_inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), 0, seqno, res);
00706    }
00707 #if 0
00708    printf("Got UDPTL packet from %s:%d (seq %d, len = %d)\n", ast_inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), seqno, res);
00709 #endif
00710    udptl_rx_packet(udptl, udptl->rawdata + AST_FRIENDLY_OFFSET, res);
00711 
00712    return &udptl->f[0];
00713 }
00714 
00715 void ast_udptl_offered_from_local(struct ast_udptl* udptl, int local)
00716 {
00717    if (udptl)
00718       udptl->udptl_offered_from_local = local;
00719    else
00720       ast_log(LOG_WARNING, "udptl structure is null\n");
00721 }
00722 
00723 int ast_udptl_get_error_correction_scheme(struct ast_udptl* udptl)
00724 {
00725    if (udptl)
00726       return udptl->error_correction_scheme;
00727    else {
00728       ast_log(LOG_WARNING, "udptl structure is null\n");
00729       return -1;
00730    }
00731 }
00732 
00733 void ast_udptl_set_error_correction_scheme(struct ast_udptl* udptl, int ec)
00734 {
00735    if (udptl) {
00736       switch (ec) {
00737       case UDPTL_ERROR_CORRECTION_FEC:
00738          udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
00739          break;
00740       case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00741          udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
00742          break;
00743       case UDPTL_ERROR_CORRECTION_NONE:
00744          udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_NONE;
00745          break;
00746       default:
00747          ast_log(LOG_WARNING, "error correction parameter invalid\n");
00748       };
00749    } else
00750       ast_log(LOG_WARNING, "udptl structure is null\n");
00751 }
00752 
00753 int ast_udptl_get_local_max_datagram(struct ast_udptl* udptl)
00754 {
00755    if (udptl)
00756       return udptl->local_max_datagram_size;
00757    else {
00758       ast_log(LOG_WARNING, "udptl structure is null\n");
00759       return -1;
00760    }
00761 }
00762 
00763 int ast_udptl_get_far_max_datagram(struct ast_udptl* udptl)
00764 {
00765    if (udptl)
00766       return udptl->far_max_datagram_size;
00767    else {
00768       ast_log(LOG_WARNING, "udptl structure is null\n");
00769       return -1;
00770    }
00771 }
00772 
00773 void ast_udptl_set_local_max_datagram(struct ast_udptl* udptl, int max_datagram)
00774 {
00775    if (udptl)
00776       udptl->local_max_datagram_size = max_datagram;
00777    else
00778       ast_log(LOG_WARNING, "udptl structure is null\n");
00779 }
00780 
00781 void ast_udptl_set_far_max_datagram(struct ast_udptl* udptl, int max_datagram)
00782 {
00783    if (udptl)
00784       udptl->far_max_datagram_size = max_datagram;
00785    else
00786       ast_log(LOG_WARNING, "udptl structure is null\n");
00787 }
00788 
00789 struct ast_udptl *ast_udptl_new_with_bindaddr(struct sched_context *sched, struct io_context *io, int callbackmode, struct in_addr addr)
00790 {
00791    struct ast_udptl *udptl;
00792    int x;
00793    int startplace;
00794    int i;
00795    long int flags;
00796 
00797    if (!(udptl = ast_calloc(1, sizeof(*udptl))))
00798       return NULL;
00799 
00800    if (udptlfectype == 2)
00801       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
00802    else if (udptlfectype == 1)
00803       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
00804    else
00805       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_NONE;
00806    udptl->error_correction_span = udptlfecspan;
00807    udptl->error_correction_entries = udptlfecentries;
00808    
00809    udptl->far_max_datagram_size = udptlmaxdatagram;
00810    udptl->local_max_datagram_size = udptlmaxdatagram;
00811 
00812    memset(&udptl->rx, 0, sizeof(udptl->rx));
00813    memset(&udptl->tx, 0, sizeof(udptl->tx));
00814    for (i = 0; i <= UDPTL_BUF_MASK; i++) {
00815       udptl->rx[i].buf_len = -1;
00816       udptl->tx[i].buf_len = -1;
00817    }
00818 
00819    udptl->seqno = ast_random() & 0xffff;
00820    udptl->them.sin_family = AF_INET;
00821    udptl->us.sin_family = AF_INET;
00822 
00823    if ((udptl->fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
00824       free(udptl);
00825       ast_log(LOG_WARNING, "Unable to allocate socket: %s\n", strerror(errno));
00826       return NULL;
00827    }
00828    flags = fcntl(udptl->fd, F_GETFL);
00829    fcntl(udptl->fd, F_SETFL, flags | O_NONBLOCK);
00830 #ifdef SO_NO_CHECK
00831    if (nochecksums)
00832       setsockopt(udptl->fd, SOL_SOCKET, SO_NO_CHECK, &nochecksums, sizeof(nochecksums));
00833 #endif
00834    /* Find us a place */
00835    x = (ast_random() % (udptlend - udptlstart)) + udptlstart;
00836    startplace = x;
00837    for (;;) {
00838       udptl->us.sin_port = htons(x);
00839       udptl->us.sin_addr = addr;
00840       if (bind(udptl->fd, (struct sockaddr *) &udptl->us, sizeof(udptl->us)) == 0)
00841          break;
00842       if (errno != EADDRINUSE) {
00843          ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno));
00844          close(udptl->fd);
00845          free(udptl);
00846          return NULL;
00847       }
00848       if (++x > udptlend)
00849          x = udptlstart;
00850       if (x == startplace) {
00851          ast_log(LOG_WARNING, "No UDPTL ports remaining\n");
00852          close(udptl->fd);
00853          free(udptl);
00854          return NULL;
00855       }
00856    }
00857    if (io && sched && callbackmode) {
00858       /* Operate this one in a callback mode */
00859       udptl->sched = sched;
00860       udptl->io = io;
00861       udptl->ioid = ast_io_add(udptl->io, udptl->fd, udptlread, AST_IO_IN, udptl);
00862    }
00863    return udptl;
00864 }
00865 
00866 struct ast_udptl *ast_udptl_new(struct sched_context *sched, struct io_context *io, int callbackmode)
00867 {
00868    struct in_addr ia;
00869    memset(&ia, 0, sizeof(ia));
00870    return ast_udptl_new_with_bindaddr(sched, io, callbackmode, ia);
00871 }
00872 
00873 int ast_udptl_settos(struct ast_udptl *udptl, int tos)
00874 {
00875    int res;
00876 
00877    if ((res = setsockopt(udptl->fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)))) 
00878       ast_log(LOG_WARNING, "UDPTL unable to set TOS to %d\n", tos);
00879    return res;
00880 }
00881 
00882 void ast_udptl_set_peer(struct ast_udptl *udptl, struct sockaddr_in *them)
00883 {
00884    udptl->them.sin_port = them->sin_port;
00885    udptl->them.sin_addr = them->sin_addr;
00886 }
00887 
00888 void ast_udptl_get_peer(struct ast_udptl *udptl, struct sockaddr_in *them)
00889 {
00890    them->sin_family = AF_INET;
00891    them->sin_port = udptl->them.sin_port;
00892    them->sin_addr = udptl->them.sin_addr;
00893 }
00894 
00895 void ast_udptl_get_us(struct ast_udptl *udptl, struct sockaddr_in *us)
00896 {
00897    memcpy(us, &udptl->us, sizeof(udptl->us));
00898 }
00899 
00900 void ast_udptl_stop(struct ast_udptl *udptl)
00901 {
00902    memset(&udptl->them.sin_addr, 0, sizeof(udptl->them.sin_addr));
00903    memset(&udptl->them.sin_port, 0, sizeof(udptl->them.sin_port));
00904 }
00905 
00906 void ast_udptl_destroy(struct ast_udptl *udptl)
00907 {
00908    if (udptl->ioid)
00909       ast_io_remove(udptl->io, udptl->ioid);
00910    if (udptl->fd > -1)
00911       close(udptl->fd);
00912    free(udptl);
00913 }
00914 
00915 int ast_udptl_write(struct ast_udptl *s, struct ast_frame *f)
00916 {
00917    int len;
00918    int res;
00919    uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
00920 
00921    /* If we have no peer, return immediately */ 
00922    if (s->them.sin_addr.s_addr == INADDR_ANY)
00923       return 0;
00924 
00925    /* If there is no data length, return immediately */
00926    if (f->datalen == 0)
00927       return 0;
00928    
00929    if (f->frametype != AST_FRAME_MODEM) {
00930       ast_log(LOG_WARNING, "UDPTL can only send T.38 data\n");
00931       return -1;
00932    }
00933 
00934    /* Cook up the UDPTL packet, with the relevant EC info. */
00935    len = udptl_build_packet(s, buf, f->data, f->datalen);
00936 
00937    if (len > 0 && s->them.sin_port && s->them.sin_addr.s_addr) {
00938       if ((res = sendto(s->fd, buf, len, 0, (struct sockaddr *) &s->them, sizeof(s->them))) < 0)
00939          ast_log(LOG_NOTICE, "UDPTL Transmission error to %s:%d: %s\n", ast_inet_ntoa(s->them.sin_addr), ntohs(s->them.sin_port), strerror(errno));
00940 #if 0
00941       printf("Sent %d bytes of UDPTL data to %s:%d\n", res, ast_inet_ntoa(udptl->them.sin_addr), ntohs(udptl->them.sin_port));
00942 #endif
00943       if (udptl_debug_test_addr(&s->them))
00944          ast_verbose("Sent UDPTL packet to %s:%d (type %d, seq %d, len %d)\n",
00945                ast_inet_ntoa(s->them.sin_addr),
00946                ntohs(s->them.sin_port), 0, s->seqno, len);
00947    }
00948       
00949    return 0;
00950 }
00951 
00952 void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto)
00953 {
00954    struct ast_udptl_protocol *cur;
00955    struct ast_udptl_protocol *prev;
00956 
00957    cur = protos;
00958    prev = NULL;
00959    while (cur) {
00960       if (cur == proto) {
00961          if (prev)
00962             prev->next = proto->next;
00963          else
00964             protos = proto->next;
00965          return;
00966       }
00967       prev = cur;
00968       cur = cur->next;
00969    }
00970 }
00971 
00972 int ast_udptl_proto_register(struct ast_udptl_protocol *proto)
00973 {
00974    struct ast_udptl_protocol *cur;
00975 
00976    cur = protos;
00977    while (cur) {
00978       if (cur->type == proto->type) {
00979          ast_log(LOG_WARNING, "Tried to register same protocol '%s' twice\n", cur->type);
00980          return -1;
00981       }
00982       cur = cur->next;
00983    }
00984    proto->next = protos;
00985    protos = proto;
00986    return 0;
00987 }
00988 
00989 static struct ast_udptl_protocol *get_proto(struct ast_channel *chan)
00990 {
00991    struct ast_udptl_protocol *cur;
00992 
00993    cur = protos;
00994    while (cur) {
00995       if (cur->type == chan->tech->type)
00996          return cur;
00997       cur = cur->next;
00998    }
00999    return NULL;
01000 }
01001 
01002 int ast_udptl_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc)
01003 {
01004    struct ast_frame *f;
01005    struct ast_channel *who;
01006    struct ast_channel *cs[3];
01007    struct ast_udptl *p0;
01008    struct ast_udptl *p1;
01009    struct ast_udptl_protocol *pr0;
01010    struct ast_udptl_protocol *pr1;
01011    struct sockaddr_in ac0;
01012    struct sockaddr_in ac1;
01013    struct sockaddr_in t0;
01014    struct sockaddr_in t1;
01015    void *pvt0;
01016    void *pvt1;
01017    int to;
01018    
01019    ast_channel_lock(c0);
01020    while (ast_channel_trylock(c1)) {
01021       ast_channel_unlock(c0);
01022       usleep(1);
01023       ast_channel_lock(c0);
01024    }
01025    pr0 = get_proto(c0);
01026    pr1 = get_proto(c1);
01027    if (!pr0) {
01028       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c0->name);
01029       ast_channel_unlock(c0);
01030       ast_channel_unlock(c1);
01031       return -1;
01032    }
01033    if (!pr1) {
01034       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c1->name);
01035       ast_channel_unlock(c0);
01036       ast_channel_unlock(c1);
01037       return -1;
01038    }
01039    pvt0 = c0->tech_pvt;
01040    pvt1 = c1->tech_pvt;
01041    p0 = pr0->get_udptl_info(c0);
01042    p1 = pr1->get_udptl_info(c1);
01043    if (!p0 || !p1) {
01044       /* Somebody doesn't want to play... */
01045       ast_channel_unlock(c0);
01046       ast_channel_unlock(c1);
01047       return -2;
01048    }
01049    if (pr0->set_udptl_peer(c0, p1)) {
01050       ast_log(LOG_WARNING, "Channel '%s' failed to talk to '%s'\n", c0->name, c1->name);
01051    } else {
01052       /* Store UDPTL peer */
01053       ast_udptl_get_peer(p1, &ac1);
01054    }
01055    if (pr1->set_udptl_peer(c1, p0))
01056       ast_log(LOG_WARNING, "Channel '%s' failed to talk back to '%s'\n", c1->name, c0->name);
01057    else {
01058       /* Store UDPTL peer */
01059       ast_udptl_get_peer(p0, &ac0);
01060    }
01061    ast_channel_unlock(c0);
01062    ast_channel_unlock(c1);
01063    cs[0] = c0;
01064    cs[1] = c1;
01065    cs[2] = NULL;
01066    for (;;) {
01067       if ((c0->tech_pvt != pvt0) ||
01068          (c1->tech_pvt != pvt1) ||
01069          (c0->masq || c0->masqr || c1->masq || c1->masqr)) {
01070             ast_log(LOG_DEBUG, "Oooh, something is weird, backing out\n");
01071             /* Tell it to try again later */
01072             return -3;
01073       }
01074       to = -1;
01075       ast_udptl_get_peer(p1, &t1);
01076       ast_udptl_get_peer(p0, &t0);
01077       if (inaddrcmp(&t1, &ac1)) {
01078          ast_log(LOG_DEBUG, "Oooh, '%s' changed end address to %s:%d\n", 
01079             c1->name, ast_inet_ntoa(t1.sin_addr), ntohs(t1.sin_port));
01080          ast_log(LOG_DEBUG, "Oooh, '%s' was %s:%d\n", 
01081             c1->name, ast_inet_ntoa(ac1.sin_addr), ntohs(ac1.sin_port));
01082          memcpy(&ac1, &t1, sizeof(ac1));
01083       }
01084       if (inaddrcmp(&t0, &ac0)) {
01085          ast_log(LOG_DEBUG, "Oooh, '%s' changed end address to %s:%d\n", 
01086             c0->name, ast_inet_ntoa(t0.sin_addr), ntohs(t0.sin_port));
01087          ast_log(LOG_DEBUG, "Oooh, '%s' was %s:%d\n", 
01088             c0->name, ast_inet_ntoa(ac0.sin_addr), ntohs(ac0.sin_port));
01089          memcpy(&ac0, &t0, sizeof(ac0));
01090       }
01091       who = ast_waitfor_n(cs, 2, &to);
01092       if (!who) {
01093          ast_log(LOG_DEBUG, "Ooh, empty read...\n");
01094          /* check for hangup / whentohangup */
01095          if (ast_check_hangup(c0) || ast_check_hangup(c1))
01096             break;
01097          continue;
01098       }
01099       f = ast_read(who);
01100       if (!f) {
01101          *fo = f;
01102          *rc = who;
01103          ast_log(LOG_DEBUG, "Oooh, got a %s\n", f ? "digit" : "hangup");
01104          /* That's all we needed */
01105          return 0;
01106       } else {
01107          if (f->frametype == AST_FRAME_MODEM) {
01108             /* Forward T.38 frames if they happen upon us */
01109             if (who == c0) {
01110                ast_write(c1, f);
01111             } else if (who == c1) {
01112                ast_write(c0, f);
01113             }
01114          }
01115          ast_frfree(f);
01116       }
01117       /* Swap priority. Not that it's a big deal at this point */
01118       cs[2] = cs[0];
01119       cs[0] = cs[1];
01120       cs[1] = cs[2];
01121    }
01122    return -1;
01123 }
01124 
01125 static int udptl_do_debug_ip(int fd, int argc, char *argv[])
01126 {
01127    struct hostent *hp;
01128    struct ast_hostent ahp;
01129    int port;
01130    char *p;
01131    char *arg;
01132 
01133    port = 0;
01134    if (argc != 4)
01135       return RESULT_SHOWUSAGE;
01136    arg = argv[3];
01137    p = strstr(arg, ":");
01138    if (p) {
01139       *p = '\0';
01140       p++;
01141       port = atoi(p);
01142    }
01143    hp = ast_gethostbyname(arg, &ahp);
01144    if (hp == NULL)
01145       return RESULT_SHOWUSAGE;
01146    udptldebugaddr.sin_family = AF_INET;
01147    memcpy(&udptldebugaddr.sin_addr, hp->h_addr, sizeof(udptldebugaddr.sin_addr));
01148    udptldebugaddr.sin_port = htons(port);
01149    if (port == 0)
01150       ast_cli(fd, "UDPTL Debugging Enabled for IP: %s\n", ast_inet_ntoa(udptldebugaddr.sin_addr));
01151    else
01152       ast_cli(fd, "UDPTL Debugging Enabled for IP: %s:%d\n", ast_inet_ntoa(udptldebugaddr.sin_addr), port);
01153    udptldebug = 1;
01154    return RESULT_SUCCESS;
01155 }
01156 
01157 static int udptl_do_debug(int fd, int argc, char *argv[])
01158 {
01159    if (argc != 2) {
01160       if (argc != 4)
01161          return RESULT_SHOWUSAGE;
01162       return udptl_do_debug_ip(fd, argc, argv);
01163    }
01164    udptldebug = 1;
01165    memset(&udptldebugaddr,0,sizeof(udptldebugaddr));
01166    ast_cli(fd, "UDPTL Debugging Enabled\n");
01167    return RESULT_SUCCESS;
01168 }
01169 
01170 static int udptl_nodebug(int fd, int argc, char *argv[])
01171 {
01172    if (argc != 3)
01173       return RESULT_SHOWUSAGE;
01174    udptldebug = 0;
01175    ast_cli(fd,"UDPTL Debugging Disabled\n");
01176    return RESULT_SUCCESS;
01177 }
01178 
01179 static char debug_usage[] =
01180   "Usage: udptl debug [ip host[:port]]\n"
01181   "       Enable dumping of all UDPTL packets to and from host.\n";
01182 
01183 static char nodebug_usage[] =
01184   "Usage: udptl debug off\n"
01185   "       Disable all UDPTL debugging\n";
01186 
01187 static struct ast_cli_entry cli_udptl_no_debug = {
01188    { "udptl", "no", "debug", NULL },
01189    udptl_nodebug, NULL,
01190    NULL };
01191 
01192 static struct ast_cli_entry cli_udptl[] = {
01193    { { "udptl", "debug", NULL },
01194    udptl_do_debug, "Enable UDPTL debugging",
01195    debug_usage },
01196 
01197    { { "udptl", "debug", "ip", NULL },
01198    udptl_do_debug, "Enable UDPTL debugging on IP",
01199    debug_usage },
01200 
01201    { { "udptl", "debug", "off", NULL },
01202    udptl_nodebug, "Disable UDPTL debugging",
01203    nodebug_usage, NULL, &cli_udptl_no_debug },
01204 };
01205 
01206 void ast_udptl_reload(void)
01207 {
01208    struct ast_config *cfg;
01209    const char *s;
01210 
01211    udptlstart = 4500;
01212    udptlend = 4999;
01213    udptlfectype = 0;
01214    udptlfecentries = 0;
01215    udptlfecspan = 0;
01216    udptlmaxdatagram = 0;
01217 
01218    if ((cfg = ast_config_load("udptl.conf"))) {
01219       if ((s = ast_variable_retrieve(cfg, "general", "udptlstart"))) {
01220          udptlstart = atoi(s);
01221          if (udptlstart < 1024)
01222             udptlstart = 1024;
01223          if (udptlstart > 65535)
01224             udptlstart = 65535;
01225       }
01226       if ((s = ast_variable_retrieve(cfg, "general", "udptlend"))) {
01227          udptlend = atoi(s);
01228          if (udptlend < 1024)
01229             udptlend = 1024;
01230          if (udptlend > 65535)
01231             udptlend = 65535;
01232       }
01233       if ((s = ast_variable_retrieve(cfg, "general", "udptlchecksums"))) {
01234 #ifdef SO_NO_CHECK
01235          if (ast_false(s))
01236             nochecksums = 1;
01237          else
01238             nochecksums = 0;
01239 #else
01240          if (ast_false(s))
01241             ast_log(LOG_WARNING, "Disabling UDPTL checksums is not supported on this operating system!\n");
01242 #endif
01243       }
01244       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxUdpEC"))) {
01245          if (strcmp(s, "t38UDPFEC") == 0)
01246             udptlfectype = 2;
01247          else if (strcmp(s, "t38UDPRedundancy") == 0)
01248             udptlfectype = 1;
01249       }
01250       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxMaxDatagram"))) {
01251          udptlmaxdatagram = atoi(s);
01252          if (udptlmaxdatagram < 0)
01253             udptlmaxdatagram = 0;
01254          if (udptlmaxdatagram > LOCAL_FAX_MAX_DATAGRAM)
01255             udptlmaxdatagram = LOCAL_FAX_MAX_DATAGRAM;
01256       }
01257       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECentries"))) {
01258          udptlfecentries = atoi(s);
01259          if (udptlfecentries < 0)
01260             udptlfecentries = 0;
01261          if (udptlfecentries > MAX_FEC_ENTRIES)
01262             udptlfecentries = MAX_FEC_ENTRIES;
01263       }
01264       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECspan"))) {
01265          udptlfecspan = atoi(s);
01266          if (udptlfecspan < 0)
01267             udptlfecspan = 0;
01268          if (udptlfecspan > MAX_FEC_SPAN)
01269             udptlfecspan = MAX_FEC_SPAN;
01270       }
01271       ast_config_destroy(cfg);
01272    }
01273    if (udptlstart >= udptlend) {
01274       ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end\n");
01275       udptlstart = 4500;
01276       udptlend = 4999;
01277    }
01278    if (option_verbose > 1)
01279       ast_verbose(VERBOSE_PREFIX_2 "UDPTL allocating from port range %d -> %d\n", udptlstart, udptlend);
01280 }
01281 
01282 void ast_udptl_init(void)
01283 {
01284    ast_cli_register_multiple(cli_udptl, sizeof(cli_udptl) / sizeof(struct ast_cli_entry));
01285    ast_udptl_reload();
01286 }

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