Mon Mar 31 07:38:05 2008

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

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