Wed Aug 18 22:33:56 2010

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) 1999-2009, Digium, Inc.
00008  *
00009  * Steve Underwood <steveu@coppice.org>
00010  * Kevin P. Fleming <kpfleming@digium.com>
00011  *
00012  * See http://www.asterisk.org for more information about
00013  * the Asterisk project. Please do not directly contact
00014  * any of the maintainers of this project for assistance;
00015  * the project provides a web site, mailing lists and IRC
00016  * channels for your use.
00017  *
00018  * This program is free software, distributed under the terms of
00019  * the GNU General Public License Version 2. See the LICENSE file
00020  * at the top of the source tree.
00021  *
00022  * A license has been granted to Digium (via disclaimer) for the use of
00023  * this code.
00024  */
00025 
00026 /*! 
00027  * \file 
00028  *
00029  * \brief UDPTL support for T.38 faxing
00030  * 
00031  *
00032  * \author Mark Spencer <markster@digium.com>
00033  * \author Steve Underwood <steveu@coppice.org>
00034  * \author Kevin P. Fleming <kpfleming@digium.com>
00035  * 
00036  * \page T38fax_udptl T.38 support :: UDPTL
00037  *
00038  * Asterisk supports T.38 fax passthrough, origination and termination. It does
00039  * not support gateway operation. The only channel driver that supports T.38 at
00040  * this time is chan_sip.
00041  *
00042  * UDPTL is handled very much like RTP. It can be reinvited to go directly between
00043  * the endpoints, without involving Asterisk in the media stream.
00044  * 
00045  * \b References:
00046  * - chan_sip.c
00047  * - udptl.c
00048  * - app_fax.c
00049  */
00050 
00051 
00052 #include "asterisk.h"
00053 
00054 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 244446 $")
00055 
00056 #include <sys/time.h>
00057 #include <signal.h>
00058 #include <fcntl.h>
00059 
00060 #include "asterisk/udptl.h"
00061 #include "asterisk/frame.h"
00062 #include "asterisk/channel.h"
00063 #include "asterisk/acl.h"
00064 #include "asterisk/config.h"
00065 #include "asterisk/lock.h"
00066 #include "asterisk/utils.h"
00067 #include "asterisk/netsock.h"
00068 #include "asterisk/cli.h"
00069 #include "asterisk/unaligned.h"
00070 
00071 #define UDPTL_MTU    1200
00072 
00073 #if !defined(FALSE)
00074 #define FALSE 0
00075 #endif
00076 #if !defined(TRUE)
00077 #define TRUE (!FALSE)
00078 #endif
00079 
00080 #define LOG_TAG(u) S_OR(u->tag, "no tag")
00081 
00082 static int udptlstart = 4500;
00083 static int udptlend = 4599;
00084 static int udptldebug;                      /*!< Are we debugging? */
00085 static struct sockaddr_in udptldebugaddr;   /*!< Debug packets to/from this host */
00086 #ifdef SO_NO_CHECK
00087 static int nochecksums;
00088 #endif
00089 static int udptlfecentries;
00090 static int udptlfecspan;
00091 static int use_even_ports;
00092 
00093 #define LOCAL_FAX_MAX_DATAGRAM      1400
00094 #define DEFAULT_FAX_MAX_DATAGRAM    400
00095 #define FAX_MAX_DATAGRAM_LIMIT      1400
00096 #define MAX_FEC_ENTRIES             5
00097 #define MAX_FEC_SPAN                5
00098 
00099 #define UDPTL_BUF_MASK              15
00100 
00101 typedef struct {
00102    int buf_len;
00103    uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
00104 } udptl_fec_tx_buffer_t;
00105 
00106 typedef struct {
00107    int buf_len;
00108    uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
00109    unsigned int fec_len[MAX_FEC_ENTRIES];
00110    uint8_t fec[MAX_FEC_ENTRIES][LOCAL_FAX_MAX_DATAGRAM];
00111    unsigned int fec_span;
00112    unsigned int fec_entries;
00113 } udptl_fec_rx_buffer_t;
00114 
00115 /*! \brief Structure for an UDPTL session */
00116 struct ast_udptl {
00117    int fd;
00118    char resp;
00119    struct ast_frame f[16];
00120    unsigned char rawdata[8192 + AST_FRIENDLY_OFFSET];
00121    unsigned int lasteventseqn;
00122    int nat;
00123    int flags;
00124    struct sockaddr_in us;
00125    struct sockaddr_in them;
00126    int *ioid;
00127    struct sched_context *sched;
00128    struct io_context *io;
00129    void *data;
00130    char *tag;
00131    ast_udptl_callback callback;
00132 
00133    /*! This option indicates the error correction scheme used in transmitted UDPTL
00134     * packets and expected in received UDPTL packets.
00135     */
00136    enum ast_t38_ec_modes error_correction_scheme;
00137 
00138    /*! This option indicates the number of error correction entries transmitted in
00139     * UDPTL packets and expected in received UDPTL packets.
00140     */
00141    unsigned int error_correction_entries;
00142 
00143    /*! This option indicates the span of the error correction entries in transmitted
00144     * UDPTL packets (FEC only).
00145     */
00146    unsigned int error_correction_span;
00147 
00148    /*! The maximum size UDPTL packet that can be accepted by
00149     * the remote device.
00150     */
00151    int far_max_datagram;
00152 
00153    /*! The maximum size UDPTL packet that we are prepared to
00154     * accept, or -1 if it hasn't been calculated since the last
00155     * changes were applied to the UDPTL structure.
00156     */
00157    int local_max_datagram;
00158 
00159    /*! The maximum IFP that can be submitted for sending
00160     * to the remote device. Calculated from far_max_datagram,
00161     * error_correction_scheme and error_correction_entries,
00162     * or -1 if it hasn't been calculated since the last
00163     * changes were applied to the UDPTL structure.
00164     */
00165    int far_max_ifp;
00166 
00167    /*! The maximum IFP that the local endpoint is prepared
00168     * to accept. Along with error_correction_scheme and
00169     * error_correction_entries, used to calculate local_max_datagram.
00170     */
00171    int local_max_ifp;
00172 
00173    int verbose;
00174 
00175    struct sockaddr_in far;
00176 
00177    unsigned int tx_seq_no;
00178    unsigned int rx_seq_no;
00179    unsigned int rx_expected_seq_no;
00180 
00181    udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1];
00182    udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1];
00183 };
00184 
00185 static AST_RWLIST_HEAD_STATIC(protos, ast_udptl_protocol);
00186 
00187 static inline int udptl_debug_test_addr(const struct sockaddr_in *addr)
00188 {
00189    if (udptldebug == 0)
00190       return 0;
00191    if (udptldebugaddr.sin_addr.s_addr) {
00192       if (((ntohs(udptldebugaddr.sin_port) != 0) &&
00193            (udptldebugaddr.sin_port != addr->sin_port)) ||
00194           (udptldebugaddr.sin_addr.s_addr != addr->sin_addr.s_addr))
00195          return 0;
00196    }
00197    return 1;
00198 }
00199 
00200 static int decode_length(uint8_t *buf, unsigned int limit, unsigned int *len, unsigned int *pvalue)
00201 {
00202    if (*len >= limit)
00203       return -1;
00204    if ((buf[*len] & 0x80) == 0) {
00205       *pvalue = buf[*len];
00206       (*len)++;
00207       return 0;
00208    }
00209    if ((buf[*len] & 0x40) == 0) {
00210       if (*len == limit - 1)
00211          return -1;
00212       *pvalue = (buf[*len] & 0x3F) << 8;
00213       (*len)++;
00214       *pvalue |= buf[*len];
00215       (*len)++;
00216       return 0;
00217    }
00218    *pvalue = (buf[*len] & 0x3F) << 14;
00219    (*len)++;
00220    /* Indicate we have a fragment */
00221    return 1;
00222 }
00223 /*- End of function --------------------------------------------------------*/
00224 
00225 static int decode_open_type(uint8_t *buf, unsigned int limit, unsigned int *len, const uint8_t **p_object, unsigned int *p_num_octets)
00226 {
00227    unsigned int octet_cnt;
00228    unsigned int octet_idx;
00229    unsigned int length;
00230    unsigned int i;
00231    const uint8_t **pbuf;
00232 
00233    for (octet_idx = 0, *p_num_octets = 0; ; octet_idx += octet_cnt) {
00234       octet_cnt = 0;
00235       if ((length = decode_length(buf, limit, len, &octet_cnt)) < 0)
00236          return -1;
00237       if (octet_cnt > 0) {
00238          *p_num_octets += octet_cnt;
00239 
00240          pbuf = &p_object[octet_idx];
00241          i = 0;
00242          /* Make sure the buffer contains at least the number of bits requested */
00243          if ((*len + octet_cnt) > limit)
00244             return -1;
00245 
00246          *pbuf = &buf[*len];
00247          *len += octet_cnt;
00248       }
00249       if (length == 0)
00250          break;
00251    }
00252    return 0;
00253 }
00254 /*- End of function --------------------------------------------------------*/
00255 
00256 static unsigned int encode_length(uint8_t *buf, unsigned int *len, unsigned int value)
00257 {
00258    unsigned int multiplier;
00259 
00260    if (value < 0x80) {
00261       /* 1 octet */
00262       buf[*len] = value;
00263       (*len)++;
00264       return value;
00265    }
00266    if (value < 0x4000) {
00267       /* 2 octets */
00268       /* Set the first bit of the first octet */
00269       buf[*len] = ((0x8000 | value) >> 8) & 0xFF;
00270       (*len)++;
00271       buf[*len] = value & 0xFF;
00272       (*len)++;
00273       return value;
00274    }
00275    /* Fragmentation */
00276    multiplier = (value < 0x10000) ? (value >> 14) : 4;
00277    /* Set the first 2 bits of the octet */
00278    buf[*len] = 0xC0 | multiplier;
00279    (*len)++;
00280    return multiplier << 14;
00281 }
00282 /*- End of function --------------------------------------------------------*/
00283 
00284 static int encode_open_type(const struct ast_udptl *udptl, uint8_t *buf, unsigned int buflen,
00285              unsigned int *len, const uint8_t *data, unsigned int num_octets)
00286 {
00287    unsigned int enclen;
00288    unsigned int octet_idx;
00289    uint8_t zero_byte;
00290 
00291    /* If open type is of zero length, add a single zero byte (10.1) */
00292    if (num_octets == 0) {
00293       zero_byte = 0;
00294       data = &zero_byte;
00295       num_octets = 1;
00296    }
00297    /* Encode the open type */
00298    for (octet_idx = 0; ; num_octets -= enclen, octet_idx += enclen) {
00299       if ((enclen = encode_length(buf, len, num_octets)) < 0)
00300          return -1;
00301       if (enclen + *len > buflen) {
00302          ast_log(LOG_ERROR, "(%s): Buffer overflow detected (%d + %d > %d)\n",
00303             LOG_TAG(udptl), enclen, *len, buflen);
00304          return -1;
00305       }
00306       if (enclen > 0) {
00307          memcpy(&buf[*len], &data[octet_idx], enclen);
00308          *len += enclen;
00309       }
00310       if (enclen >= num_octets)
00311          break;
00312    }
00313 
00314    return 0;
00315 }
00316 /*- End of function --------------------------------------------------------*/
00317 
00318 static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, unsigned int len)
00319 {
00320    int stat1;
00321    int stat2;
00322    int i;
00323    int j;
00324    int k;
00325    int l;
00326    int m;
00327    int x;
00328    int limit;
00329    int which;
00330    unsigned int ptr;
00331    unsigned int count;
00332    int total_count;
00333    int seq_no;
00334    const uint8_t *ifp;
00335    const uint8_t *data;
00336    unsigned int ifp_len;
00337    int repaired[16];
00338    const uint8_t *bufs[16];
00339    unsigned int lengths[16];
00340    int span;
00341    int entries;
00342    int ifp_no;
00343 
00344    ptr = 0;
00345    ifp_no = 0;
00346    memset(&s->f[0], 0, sizeof(s->f[0]));
00347 
00348    /* Decode seq_number */
00349    if (ptr + 2 > len)
00350       return -1;
00351    seq_no = (buf[0] << 8) | buf[1];
00352    ptr += 2;
00353 
00354    /* Break out the primary packet */
00355    if ((stat1 = decode_open_type(buf, len, &ptr, &ifp, &ifp_len)) != 0)
00356       return -1;
00357    /* Decode error_recovery */
00358    if (ptr + 1 > len)
00359       return -1;
00360    if ((buf[ptr++] & 0x80) == 0) {
00361       /* Secondary packet mode for error recovery */
00362       if (seq_no > s->rx_seq_no) {
00363          /* We received a later packet than we expected, so we need to check if we can fill in the gap from the
00364             secondary packets. */
00365          total_count = 0;
00366          do {
00367             if ((stat2 = decode_length(buf, len, &ptr, &count)) < 0)
00368                return -1;
00369             for (i = 0; i < count; i++) {
00370                if ((stat1 = decode_open_type(buf, len, &ptr, &bufs[total_count + i], &lengths[total_count + i])) != 0)
00371                   return -1;
00372             }
00373             total_count += count;
00374          }
00375          while (stat2 > 0);
00376          /* Step through in reverse order, so we go oldest to newest */
00377          for (i = total_count; i > 0; i--) {
00378             if (seq_no - i >= s->rx_seq_no) {
00379                /* This one wasn't seen before */
00380                /* Decode the secondary IFP packet */
00381                //fprintf(stderr, "Secondary %d, len %d\n", seq_no - i, lengths[i - 1]);
00382                s->f[ifp_no].frametype = AST_FRAME_MODEM;
00383                s->f[ifp_no].subclass = AST_MODEM_T38;
00384 
00385                s->f[ifp_no].mallocd = 0;
00386                s->f[ifp_no].seqno = seq_no - i;
00387                s->f[ifp_no].datalen = lengths[i - 1];
00388                s->f[ifp_no].data.ptr = (uint8_t *) bufs[i - 1];
00389                s->f[ifp_no].offset = 0;
00390                s->f[ifp_no].src = "UDPTL";
00391                if (ifp_no > 0)
00392                   AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00393                AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00394                ifp_no++;
00395             }
00396          }
00397       }
00398    }
00399    else
00400    {
00401       /* FEC mode for error recovery */
00402       /* Our buffers cannot tolerate overlength IFP packets in FEC mode */
00403       if (ifp_len > LOCAL_FAX_MAX_DATAGRAM)
00404          return -1;
00405       /* Update any missed slots in the buffer */
00406       for ( ; seq_no > s->rx_seq_no; s->rx_seq_no++) {
00407          x = s->rx_seq_no & UDPTL_BUF_MASK;
00408          s->rx[x].buf_len = -1;
00409          s->rx[x].fec_len[0] = 0;
00410          s->rx[x].fec_span = 0;
00411          s->rx[x].fec_entries = 0;
00412       }
00413 
00414       x = seq_no & UDPTL_BUF_MASK;
00415 
00416       memset(repaired, 0, sizeof(repaired));
00417 
00418       /* Save the new IFP packet */
00419       memcpy(s->rx[x].buf, ifp, ifp_len);
00420       s->rx[x].buf_len = ifp_len;
00421       repaired[x] = TRUE;
00422 
00423       /* Decode the FEC packets */
00424       /* The span is defined as an unconstrained integer, but will never be more
00425          than a small value. */
00426       if (ptr + 2 > len)
00427          return -1;
00428       if (buf[ptr++] != 1)
00429          return -1;
00430       span = buf[ptr++];
00431       s->rx[x].fec_span = span;
00432 
00433       /* The number of entries is defined as a length, but will only ever be a small
00434          value. Treat it as such. */
00435       if (ptr + 1 > len)
00436          return -1;
00437       entries = buf[ptr++];
00438       s->rx[x].fec_entries = entries;
00439 
00440       /* Decode the elements */
00441       for (i = 0; i < entries; i++) {
00442          if ((stat1 = decode_open_type(buf, len, &ptr, &data, &s->rx[x].fec_len[i])) != 0)
00443             return -1;
00444          if (s->rx[x].fec_len[i] > LOCAL_FAX_MAX_DATAGRAM)
00445             return -1;
00446 
00447          /* Save the new FEC data */
00448          memcpy(s->rx[x].fec[i], data, s->rx[x].fec_len[i]);
00449 #if 0
00450          fprintf(stderr, "FEC: ");
00451          for (j = 0; j < s->rx[x].fec_len[i]; j++)
00452             fprintf(stderr, "%02X ", data[j]);
00453          fprintf(stderr, "\n");
00454 #endif
00455       }
00456 
00457       /* See if we can reconstruct anything which is missing */
00458       /* TODO: this does not comprehensively hunt back and repair everything that is possible */
00459       for (l = x; l != ((x - (16 - span*entries)) & UDPTL_BUF_MASK); l = (l - 1) & UDPTL_BUF_MASK) {
00460          if (s->rx[l].fec_len[0] <= 0)
00461             continue;
00462          for (m = 0; m < s->rx[l].fec_entries; m++) {
00463             limit = (l + m) & UDPTL_BUF_MASK;
00464             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) {
00465                if (s->rx[k].buf_len <= 0)
00466                   which = (which == -1) ? k : -2;
00467             }
00468             if (which >= 0) {
00469                /* Repairable */
00470                for (j = 0; j < s->rx[l].fec_len[m]; j++) {
00471                   s->rx[which].buf[j] = s->rx[l].fec[m][j];
00472                   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)
00473                      s->rx[which].buf[j] ^= (s->rx[k].buf_len > j) ? s->rx[k].buf[j] : 0;
00474                }
00475                s->rx[which].buf_len = s->rx[l].fec_len[m];
00476                repaired[which] = TRUE;
00477             }
00478          }
00479       }
00480       /* Now play any new packets forwards in time */
00481       for (l = (x + 1) & UDPTL_BUF_MASK, j = seq_no - UDPTL_BUF_MASK; l != x; l = (l + 1) & UDPTL_BUF_MASK, j++) {
00482          if (repaired[l]) {
00483             //fprintf(stderr, "Fixed packet %d, len %d\n", j, l);
00484             s->f[ifp_no].frametype = AST_FRAME_MODEM;
00485             s->f[ifp_no].subclass = AST_MODEM_T38;
00486          
00487             s->f[ifp_no].mallocd = 0;
00488             s->f[ifp_no].seqno = j;
00489             s->f[ifp_no].datalen = s->rx[l].buf_len;
00490             s->f[ifp_no].data.ptr = s->rx[l].buf;
00491             s->f[ifp_no].offset = 0;
00492             s->f[ifp_no].src = "UDPTL";
00493             if (ifp_no > 0)
00494                AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00495             AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00496             ifp_no++;
00497          }
00498       }
00499    }
00500 
00501    /* If packets are received out of sequence, we may have already processed this packet from the error
00502       recovery information in a packet already received. */
00503    if (seq_no >= s->rx_seq_no) {
00504       /* Decode the primary IFP packet */
00505       s->f[ifp_no].frametype = AST_FRAME_MODEM;
00506       s->f[ifp_no].subclass = AST_MODEM_T38;
00507       
00508       s->f[ifp_no].mallocd = 0;
00509       s->f[ifp_no].seqno = seq_no;
00510       s->f[ifp_no].datalen = ifp_len;
00511       s->f[ifp_no].data.ptr = (uint8_t *) ifp;
00512       s->f[ifp_no].offset = 0;
00513       s->f[ifp_no].src = "UDPTL";
00514       if (ifp_no > 0)
00515          AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00516       AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00517 
00518       ifp_no++;
00519    }
00520 
00521    s->rx_seq_no = seq_no + 1;
00522    return ifp_no;
00523 }
00524 /*- End of function --------------------------------------------------------*/
00525 
00526 static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, unsigned int buflen, uint8_t *ifp, unsigned int ifp_len)
00527 {
00528    uint8_t fec[LOCAL_FAX_MAX_DATAGRAM * 2];
00529    int i;
00530    int j;
00531    int seq;
00532    int entry;
00533    int entries;
00534    int span;
00535    int m;
00536    unsigned int len;
00537    int limit;
00538    int high_tide;
00539 
00540    seq = s->tx_seq_no & 0xFFFF;
00541 
00542    /* Map the sequence number to an entry in the circular buffer */
00543    entry = seq & UDPTL_BUF_MASK;
00544 
00545    /* We save the message in a circular buffer, for generating FEC or
00546       redundancy sets later on. */
00547    s->tx[entry].buf_len = ifp_len;
00548    memcpy(s->tx[entry].buf, ifp, ifp_len);
00549    
00550    /* Build the UDPTLPacket */
00551 
00552    len = 0;
00553    /* Encode the sequence number */
00554    buf[len++] = (seq >> 8) & 0xFF;
00555    buf[len++] = seq & 0xFF;
00556 
00557    /* Encode the primary IFP packet */
00558    if (encode_open_type(s, buf, buflen, &len, ifp, ifp_len) < 0)
00559       return -1;
00560 
00561    /* Encode the appropriate type of error recovery information */
00562    switch (s->error_correction_scheme)
00563    {
00564    case UDPTL_ERROR_CORRECTION_NONE:
00565       /* Encode the error recovery type */
00566       buf[len++] = 0x00;
00567       /* The number of entries will always be zero, so it is pointless allowing
00568          for the fragmented case here. */
00569       if (encode_length(buf, &len, 0) < 0)
00570          return -1;
00571       break;
00572    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00573       /* Encode the error recovery type */
00574       buf[len++] = 0x00;
00575       if (s->tx_seq_no > s->error_correction_entries)
00576          entries = s->error_correction_entries;
00577       else
00578          entries = s->tx_seq_no;
00579       /* The number of entries will always be small, so it is pointless allowing
00580          for the fragmented case here. */
00581       if (encode_length(buf, &len, entries) < 0)
00582          return -1;
00583       /* Encode the elements */
00584       for (i = 0; i < entries; i++) {
00585          j = (entry - i - 1) & UDPTL_BUF_MASK;
00586          if (encode_open_type(s, buf, buflen, &len, s->tx[j].buf, s->tx[j].buf_len) < 0) {
00587             ast_debug(1, "(%s): Encoding failed at i=%d, j=%d\n",
00588                  LOG_TAG(s), i, j);
00589             return -1;
00590          }
00591       }
00592       break;
00593    case UDPTL_ERROR_CORRECTION_FEC:
00594       span = s->error_correction_span;
00595       entries = s->error_correction_entries;
00596       if (seq < s->error_correction_span*s->error_correction_entries) {
00597          /* In the initial stages, wind up the FEC smoothly */
00598          entries = seq/s->error_correction_span;
00599          if (seq < s->error_correction_span)
00600             span = 0;
00601       }
00602       /* Encode the error recovery type */
00603       buf[len++] = 0x80;
00604       /* Span is defined as an inconstrained integer, which it dumb. It will only
00605          ever be a small value. Treat it as such. */
00606       buf[len++] = 1;
00607       buf[len++] = span;
00608       /* The number of entries is defined as a length, but will only ever be a small
00609          value. Treat it as such. */
00610       buf[len++] = entries;
00611       for (m = 0; m < entries; m++) {
00612          /* Make an XOR'ed entry the maximum length */
00613          limit = (entry + m) & UDPTL_BUF_MASK;
00614          high_tide = 0;
00615          for (i = (limit - span*entries) & UDPTL_BUF_MASK; i != limit; i = (i + entries) & UDPTL_BUF_MASK) {
00616             if (high_tide < s->tx[i].buf_len) {
00617                for (j = 0; j < high_tide; j++)
00618                   fec[j] ^= s->tx[i].buf[j];
00619                for ( ; j < s->tx[i].buf_len; j++)
00620                   fec[j] = s->tx[i].buf[j];
00621                high_tide = s->tx[i].buf_len;
00622             } else {
00623                for (j = 0; j < s->tx[i].buf_len; j++)
00624                   fec[j] ^= s->tx[i].buf[j];
00625             }
00626          }
00627          if (encode_open_type(s, buf, buflen, &len, fec, high_tide) < 0)
00628             return -1;
00629       }
00630       break;
00631    }
00632 
00633    if (s->verbose)
00634       fprintf(stderr, "\n");
00635 
00636    s->tx_seq_no++;
00637    return len;
00638 }
00639 
00640 int ast_udptl_fd(const struct ast_udptl *udptl)
00641 {
00642    return udptl->fd;
00643 }
00644 
00645 void ast_udptl_set_data(struct ast_udptl *udptl, void *data)
00646 {
00647    udptl->data = data;
00648 }
00649 
00650 void ast_udptl_set_callback(struct ast_udptl *udptl, ast_udptl_callback callback)
00651 {
00652    udptl->callback = callback;
00653 }
00654 
00655 void ast_udptl_setnat(struct ast_udptl *udptl, int nat)
00656 {
00657    udptl->nat = nat;
00658 }
00659 
00660 static int udptlread(int *id, int fd, short events, void *cbdata)
00661 {
00662    struct ast_udptl *udptl = cbdata;
00663    struct ast_frame *f;
00664 
00665    if ((f = ast_udptl_read(udptl))) {
00666       if (udptl->callback)
00667          udptl->callback(udptl, f, udptl->data);
00668    }
00669    return 1;
00670 }
00671 
00672 struct ast_frame *ast_udptl_read(struct ast_udptl *udptl)
00673 {
00674    int res;
00675    struct sockaddr_in sin;
00676    socklen_t len;
00677    uint16_t seqno = 0;
00678    uint16_t *udptlheader;
00679 
00680    len = sizeof(sin);
00681    
00682    /* Cache where the header will go */
00683    res = recvfrom(udptl->fd,
00684          udptl->rawdata + AST_FRIENDLY_OFFSET,
00685          sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET,
00686          0,
00687          (struct sockaddr *) &sin,
00688          &len);
00689    udptlheader = (uint16_t *)(udptl->rawdata + AST_FRIENDLY_OFFSET);
00690    if (res < 0) {
00691       if (errno != EAGAIN)
00692          ast_log(LOG_WARNING, "(%s): UDPTL read error: %s\n",
00693             LOG_TAG(udptl), strerror(errno));
00694       ast_assert(errno != EBADF);
00695       return &ast_null_frame;
00696    }
00697 
00698    /* Ignore if the other side hasn't been given an address yet. */
00699    if (!udptl->them.sin_addr.s_addr || !udptl->them.sin_port)
00700       return &ast_null_frame;
00701 
00702    if (udptl->nat) {
00703       /* Send to whoever sent to us */
00704       if ((udptl->them.sin_addr.s_addr != sin.sin_addr.s_addr) ||
00705          (udptl->them.sin_port != sin.sin_port)) {
00706          memcpy(&udptl->them, &sin, sizeof(udptl->them));
00707          ast_debug(1, "UDPTL NAT (%s): Using address %s:%d\n",
00708               LOG_TAG(udptl), ast_inet_ntoa(udptl->them.sin_addr), ntohs(udptl->them.sin_port));
00709       }
00710    }
00711 
00712    if (udptl_debug_test_addr(&sin)) {
00713       ast_verb(1, "UDPTL (%s): packet from %s:%d (type %d, seq %d, len %d)\n",
00714           LOG_TAG(udptl), ast_inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), 0, seqno, res);
00715    }
00716    if (udptl_rx_packet(udptl, udptl->rawdata + AST_FRIENDLY_OFFSET, res) < 1)
00717       return &ast_null_frame;
00718 
00719    return &udptl->f[0];
00720 }
00721 
00722 static void calculate_local_max_datagram(struct ast_udptl *udptl)
00723 {
00724    unsigned int new_max = 0;
00725 
00726    if (udptl->local_max_ifp == -1) {
00727       ast_log(LOG_WARNING, "(%s): Cannot calculate local_max_datagram before local_max_ifp has been set.\n",
00728          LOG_TAG(udptl));
00729       udptl->local_max_datagram = -1;
00730       return;
00731    }
00732 
00733    /* calculate the amount of space required to receive an IFP
00734     * of the maximum size supported by the application/endpoint
00735     * that we are delivering them to (local endpoint), and add
00736     * the amount of space required to support the selected
00737     * error correction mode
00738     */
00739    switch (udptl->error_correction_scheme) {
00740    case UDPTL_ERROR_CORRECTION_NONE:
00741       /* need room for sequence number, length indicator, redundancy
00742        * indicator and following length indicator
00743        */
00744       new_max = 5 + udptl->local_max_ifp;
00745       break;
00746    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00747       /* need room for sequence number, length indicators, plus
00748        * room for up to 3 redundancy packets
00749        */
00750       new_max = 5 + udptl->local_max_ifp + 2 + (3 * udptl->local_max_ifp);
00751       break;
00752    case UDPTL_ERROR_CORRECTION_FEC:
00753       /* need room for sequence number, length indicators and a
00754        * a single IFP of the maximum size expected
00755        */
00756       new_max = 5 + udptl->local_max_ifp + 4 + udptl->local_max_ifp;
00757       break;
00758    }
00759    /* add 5% extra space for insurance, but no larger than LOCAL_FAX_MAX_DATAGRAM */
00760    udptl->local_max_datagram = MIN(new_max * 1.05, LOCAL_FAX_MAX_DATAGRAM);
00761 }
00762 
00763 static void calculate_far_max_ifp(struct ast_udptl *udptl)
00764 {
00765    unsigned new_max = 0;
00766 
00767    if (udptl->far_max_datagram == -1) {
00768       ast_log(LOG_WARNING, "(%s): Cannot calculate far_max_ifp before far_max_datagram has been set.\n",
00769          LOG_TAG(udptl));
00770       udptl->far_max_ifp = -1;
00771       return;
00772    }
00773 
00774    /* the goal here is to supply the local endpoint (application
00775     * or bridged channel) a maximum IFP value that will allow it
00776     * to effectively and efficiently transfer image data at its
00777     * selected bit rate, taking into account the selected error
00778     * correction mode, but without overrunning the far endpoint's
00779     * datagram buffer. this is complicated by the fact that some
00780     * far endpoints send us bogus (small) max datagram values,
00781     * which would result in either buffer overrun or no error
00782     * correction. we try to accomodate those, but if the supplied
00783     * value is too small to do so, we'll emit warning messages and
00784     * the user will have to use configuration options to override
00785     * the max datagram value supplied by the far endpoint.
00786     */
00787    switch (udptl->error_correction_scheme) {
00788    case UDPTL_ERROR_CORRECTION_NONE:
00789       /* need room for sequence number, length indicator, redundancy
00790        * indicator and following length indicator
00791        */
00792       new_max = udptl->far_max_datagram - 5;
00793       break;
00794    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00795       /* for this case, we'd like to send as many error correction entries
00796        * as possible (up to the number we're configured for), but we'll settle
00797        * for sending fewer if the configured number would cause the
00798        * calculated max IFP to be too small for effective operation
00799        *
00800        * need room for sequence number, length indicators and the
00801        * configured number of redundant packets
00802        *
00803        * note: we purposely don't allow error_correction_entries to drop to
00804        * zero in this loop; we'd rather send smaller IFPs (and thus reduce
00805        * the image data transfer rate) than sacrifice redundancy completely
00806        */
00807       for (;;) {
00808          new_max = (udptl->far_max_datagram - 8) / (udptl->error_correction_entries + 1);
00809 
00810          if ((new_max < 80) && (udptl->error_correction_entries > 1)) {
00811             /* the max ifp is not large enough, subtract an
00812              * error correction entry and calculate again
00813              * */
00814             --udptl->error_correction_entries;
00815          } else {
00816             break;
00817          }
00818       }
00819       break;
00820    case UDPTL_ERROR_CORRECTION_FEC:
00821       /* need room for sequence number, length indicators and a
00822        * a single IFP of the maximum size expected
00823        */
00824       new_max = (udptl->far_max_datagram - 10) / 2;
00825       break;
00826    }
00827    /* subtract 5% of space for insurance */
00828    udptl->far_max_ifp = new_max * 0.95;
00829 }
00830 
00831 enum ast_t38_ec_modes ast_udptl_get_error_correction_scheme(const struct ast_udptl *udptl)
00832 {
00833    return udptl->error_correction_scheme;
00834 }
00835 
00836 void ast_udptl_set_error_correction_scheme(struct ast_udptl *udptl, enum ast_t38_ec_modes ec)
00837 {
00838    udptl->error_correction_scheme = ec;
00839    switch (ec) {
00840    case UDPTL_ERROR_CORRECTION_FEC:
00841       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
00842       if (udptl->error_correction_entries == 0) {
00843          udptl->error_correction_entries = 3;
00844       }
00845       if (udptl->error_correction_span == 0) {
00846          udptl->error_correction_span = 3;
00847       }
00848       break;
00849    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00850       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
00851       if (udptl->error_correction_entries == 0) {
00852          udptl->error_correction_entries = 3;
00853       }
00854       break;
00855    default:
00856       /* nothing to do */
00857       break;
00858    };
00859    /* reset calculated values so they'll be computed again */
00860    udptl->local_max_datagram = -1;
00861    udptl->far_max_ifp = -1;
00862 }
00863 
00864 void ast_udptl_set_local_max_ifp(struct ast_udptl *udptl, unsigned int max_ifp)
00865 {
00866    /* make sure max_ifp is a positive value since a cast will take place when
00867     * when setting local_max_ifp */
00868    if ((signed int) max_ifp > 0) {
00869       udptl->local_max_ifp = max_ifp;
00870       /* reset calculated values so they'll be computed again */
00871       udptl->local_max_datagram = -1;
00872    }
00873 }
00874 
00875 unsigned int ast_udptl_get_local_max_datagram(struct ast_udptl *udptl)
00876 {
00877    if (udptl->local_max_datagram == -1) {
00878       calculate_local_max_datagram(udptl);
00879    }
00880 
00881    /* this function expects a unsigned value in return. */
00882    if (udptl->local_max_datagram < 0) {
00883       return 0;
00884    }
00885    return udptl->local_max_datagram;
00886 }
00887 
00888 void ast_udptl_set_far_max_datagram(struct ast_udptl *udptl, unsigned int max_datagram)
00889 {
00890    if (!max_datagram || (max_datagram > FAX_MAX_DATAGRAM_LIMIT)) {
00891       udptl->far_max_datagram = DEFAULT_FAX_MAX_DATAGRAM;
00892    } else {
00893       udptl->far_max_datagram = max_datagram;
00894    }
00895    /* reset calculated values so they'll be computed again */
00896    udptl->far_max_ifp = -1;
00897 }
00898 
00899 unsigned int ast_udptl_get_far_max_datagram(const struct ast_udptl *udptl)
00900 {
00901    if (udptl->far_max_datagram < 0) {
00902       return 0;
00903    }
00904    return udptl->far_max_datagram;
00905 }
00906 
00907 unsigned int ast_udptl_get_far_max_ifp(struct ast_udptl *udptl)
00908 {
00909    if (udptl->far_max_ifp == -1) {
00910       calculate_far_max_ifp(udptl);
00911    }
00912 
00913    if (udptl->far_max_ifp < 0) {
00914       return 0;
00915    }
00916    return udptl->far_max_ifp;
00917 }
00918 
00919 struct ast_udptl *ast_udptl_new_with_bindaddr(struct sched_context *sched, struct io_context *io, int callbackmode, struct in_addr addr)
00920 {
00921    struct ast_udptl *udptl;
00922    int x;
00923    int startplace;
00924    int i;
00925    long int flags;
00926 
00927    if (!(udptl = ast_calloc(1, sizeof(*udptl))))
00928       return NULL;
00929 
00930    udptl->error_correction_span = udptlfecspan;
00931    udptl->error_correction_entries = udptlfecentries;
00932    
00933    udptl->far_max_datagram = -1;
00934    udptl->far_max_ifp = -1;
00935    udptl->local_max_ifp = -1;
00936    udptl->local_max_datagram = -1;
00937 
00938    for (i = 0; i <= UDPTL_BUF_MASK; i++) {
00939       udptl->rx[i].buf_len = -1;
00940       udptl->tx[i].buf_len = -1;
00941    }
00942 
00943    udptl->them.sin_family = AF_INET;
00944    udptl->us.sin_family = AF_INET;
00945 
00946    if ((udptl->fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
00947       ast_free(udptl);
00948       ast_log(LOG_WARNING, "Unable to allocate socket: %s\n", strerror(errno));
00949       return NULL;
00950    }
00951    flags = fcntl(udptl->fd, F_GETFL);
00952    fcntl(udptl->fd, F_SETFL, flags | O_NONBLOCK);
00953 #ifdef SO_NO_CHECK
00954    if (nochecksums)
00955       setsockopt(udptl->fd, SOL_SOCKET, SO_NO_CHECK, &nochecksums, sizeof(nochecksums));
00956 #endif
00957    /* Find us a place */
00958    x = (udptlstart == udptlend) ? udptlstart : (ast_random() % (udptlend - udptlstart)) + udptlstart;
00959    if (use_even_ports && (x & 1)) {
00960       ++x;
00961    }
00962    startplace = x;
00963    for (;;) {
00964       udptl->us.sin_port = htons(x);
00965       udptl->us.sin_addr = addr;
00966       if (bind(udptl->fd, (struct sockaddr *) &udptl->us, sizeof(udptl->us)) == 0)
00967          break;
00968       if (errno != EADDRINUSE) {
00969          ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno));
00970          close(udptl->fd);
00971          ast_free(udptl);
00972          return NULL;
00973       }
00974       if (use_even_ports) {
00975          x += 2;
00976       } else {
00977          ++x;
00978       }
00979       if (x > udptlend)
00980          x = udptlstart;
00981       if (x == startplace) {
00982          ast_log(LOG_WARNING, "No UDPTL ports remaining\n");
00983          close(udptl->fd);
00984          ast_free(udptl);
00985          return NULL;
00986       }
00987    }
00988    if (io && sched && callbackmode) {
00989       /* Operate this one in a callback mode */
00990       udptl->sched = sched;
00991       udptl->io = io;
00992       udptl->ioid = ast_io_add(udptl->io, udptl->fd, udptlread, AST_IO_IN, udptl);
00993    }
00994    return udptl;
00995 }
00996 
00997 struct ast_udptl *ast_udptl_new(struct sched_context *sched, struct io_context *io, int callbackmode)
00998 {
00999    struct in_addr ia;
01000    memset(&ia, 0, sizeof(ia));
01001    return ast_udptl_new_with_bindaddr(sched, io, callbackmode, ia);
01002 }
01003 
01004 void ast_udptl_set_tag(struct ast_udptl *udptl, const char *format, ...)
01005 {
01006    va_list ap;
01007 
01008    if (udptl->tag) {
01009       ast_free(udptl->tag);
01010       udptl->tag = NULL;
01011    }
01012    va_start(ap, format);
01013    if (ast_vasprintf(&udptl->tag, format, ap) == -1) {
01014       udptl->tag = NULL;
01015    }
01016    va_end(ap);
01017 }
01018 
01019 int ast_udptl_setqos(struct ast_udptl *udptl, unsigned int tos, unsigned int cos)
01020 {
01021    return ast_netsock_set_qos(udptl->fd, tos, cos, "UDPTL");
01022 }
01023 
01024 void ast_udptl_set_peer(struct ast_udptl *udptl, const struct sockaddr_in *them)
01025 {
01026    udptl->them.sin_port = them->sin_port;
01027    udptl->them.sin_addr = them->sin_addr;
01028 }
01029 
01030 void ast_udptl_get_peer(const struct ast_udptl *udptl, struct sockaddr_in *them)
01031 {
01032    memset(them, 0, sizeof(*them));
01033    them->sin_family = AF_INET;
01034    them->sin_port = udptl->them.sin_port;
01035    them->sin_addr = udptl->them.sin_addr;
01036 }
01037 
01038 void ast_udptl_get_us(const struct ast_udptl *udptl, struct sockaddr_in *us)
01039 {
01040    memcpy(us, &udptl->us, sizeof(udptl->us));
01041 }
01042 
01043 void ast_udptl_stop(struct ast_udptl *udptl)
01044 {
01045    memset(&udptl->them.sin_addr, 0, sizeof(udptl->them.sin_addr));
01046    memset(&udptl->them.sin_port, 0, sizeof(udptl->them.sin_port));
01047 }
01048 
01049 void ast_udptl_destroy(struct ast_udptl *udptl)
01050 {
01051    if (udptl->ioid)
01052       ast_io_remove(udptl->io, udptl->ioid);
01053    if (udptl->fd > -1)
01054       close(udptl->fd);
01055    if (udptl->tag)
01056       ast_free(udptl->tag);
01057    ast_free(udptl);
01058 }
01059 
01060 int ast_udptl_write(struct ast_udptl *s, struct ast_frame *f)
01061 {
01062    unsigned int seq;
01063    unsigned int len = f->datalen;
01064    int res;
01065    /* if no max datagram size is provided, use default value */
01066    const int bufsize = (s->far_max_datagram > 0) ? s->far_max_datagram : DEFAULT_FAX_MAX_DATAGRAM;
01067    uint8_t buf[bufsize];
01068 
01069    memset(buf, 0, sizeof(buf));
01070 
01071    /* If we have no peer, return immediately */ 
01072    if (s->them.sin_addr.s_addr == INADDR_ANY)
01073       return 0;
01074 
01075    /* If there is no data length, return immediately */
01076    if (f->datalen == 0)
01077       return 0;
01078    
01079    if ((f->frametype != AST_FRAME_MODEM) ||
01080        (f->subclass != AST_MODEM_T38)) {
01081       ast_log(LOG_WARNING, "(%s): UDPTL can only send T.38 data.\n",
01082          LOG_TAG(s));
01083       return -1;
01084    }
01085 
01086    if (len > s->far_max_ifp) {
01087       ast_log(LOG_WARNING,
01088          "(%s): UDPTL asked to send %d bytes of IFP when far end only prepared to accept %d bytes; data loss will occur."
01089          "You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.\n",
01090          LOG_TAG(s), len, s->far_max_ifp);
01091       len = s->far_max_ifp;
01092    }
01093 
01094    /* Save seq_no for debug output because udptl_build_packet increments it */
01095    seq = s->tx_seq_no & 0xFFFF;
01096 
01097    /* Cook up the UDPTL packet, with the relevant EC info. */
01098    len = udptl_build_packet(s, buf, sizeof(buf), f->data.ptr, len);
01099 
01100    if (len > 0 && s->them.sin_port && s->them.sin_addr.s_addr) {
01101       if ((res = sendto(s->fd, buf, len, 0, (struct sockaddr *) &s->them, sizeof(s->them))) < 0)
01102          ast_log(LOG_NOTICE, "(%s): UDPTL Transmission error to %s:%d: %s\n",
01103             LOG_TAG(s), ast_inet_ntoa(s->them.sin_addr), ntohs(s->them.sin_port), strerror(errno));
01104       if (udptl_debug_test_addr(&s->them))
01105          ast_verb(1, "UDPTL (%s): packet to %s:%d (type %d, seq %d, len %d)\n",
01106              LOG_TAG(s), ast_inet_ntoa(s->them.sin_addr), ntohs(s->them.sin_port), 0, seq, len);
01107    }
01108       
01109    return 0;
01110 }
01111 
01112 void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto)
01113 {
01114    AST_RWLIST_WRLOCK(&protos);
01115    AST_RWLIST_REMOVE(&protos, proto, list);
01116    AST_RWLIST_UNLOCK(&protos);
01117 }
01118 
01119 int ast_udptl_proto_register(struct ast_udptl_protocol *proto)
01120 {
01121    struct ast_udptl_protocol *cur;
01122 
01123    AST_RWLIST_WRLOCK(&protos);
01124    AST_RWLIST_TRAVERSE(&protos, cur, list) {
01125       if (cur->type == proto->type) {
01126          ast_log(LOG_WARNING, "Tried to register same protocol '%s' twice\n", cur->type);
01127          AST_RWLIST_UNLOCK(&protos);
01128          return -1;
01129       }
01130    }
01131    AST_RWLIST_INSERT_TAIL(&protos, proto, list);
01132    AST_RWLIST_UNLOCK(&protos);
01133    return 0;
01134 }
01135 
01136 static struct ast_udptl_protocol *get_proto(struct ast_channel *chan)
01137 {
01138    struct ast_udptl_protocol *cur = NULL;
01139 
01140    AST_RWLIST_RDLOCK(&protos);
01141    AST_RWLIST_TRAVERSE(&protos, cur, list) {
01142       if (cur->type == chan->tech->type)
01143          break;
01144    }
01145    AST_RWLIST_UNLOCK(&protos);
01146 
01147    return cur;
01148 }
01149 
01150 int ast_udptl_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc)
01151 {
01152    struct ast_frame *f;
01153    struct ast_channel *who;
01154    struct ast_channel *cs[3];
01155    struct ast_udptl *p0;
01156    struct ast_udptl *p1;
01157    struct ast_udptl_protocol *pr0;
01158    struct ast_udptl_protocol *pr1;
01159    struct sockaddr_in ac0;
01160    struct sockaddr_in ac1;
01161    struct sockaddr_in t0;
01162    struct sockaddr_in t1;
01163    void *pvt0;
01164    void *pvt1;
01165    int to;
01166    
01167    ast_channel_lock(c0);
01168    while (ast_channel_trylock(c1)) {
01169       ast_channel_unlock(c0);
01170       usleep(1);
01171       ast_channel_lock(c0);
01172    }
01173    pr0 = get_proto(c0);
01174    pr1 = get_proto(c1);
01175    if (!pr0) {
01176       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c0->name);
01177       ast_channel_unlock(c0);
01178       ast_channel_unlock(c1);
01179       return -1;
01180    }
01181    if (!pr1) {
01182       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c1->name);
01183       ast_channel_unlock(c0);
01184       ast_channel_unlock(c1);
01185       return -1;
01186    }
01187    pvt0 = c0->tech_pvt;
01188    pvt1 = c1->tech_pvt;
01189    p0 = pr0->get_udptl_info(c0);
01190    p1 = pr1->get_udptl_info(c1);
01191    if (!p0 || !p1) {
01192       /* Somebody doesn't want to play... */
01193       ast_channel_unlock(c0);
01194       ast_channel_unlock(c1);
01195       return -2;
01196    }
01197    if (pr0->set_udptl_peer(c0, p1)) {
01198       ast_log(LOG_WARNING, "Channel '%s' failed to talk to '%s'\n", c0->name, c1->name);
01199       memset(&ac1, 0, sizeof(ac1));
01200    } else {
01201       /* Store UDPTL peer */
01202       ast_udptl_get_peer(p1, &ac1);
01203    }
01204    if (pr1->set_udptl_peer(c1, p0)) {
01205       ast_log(LOG_WARNING, "Channel '%s' failed to talk back to '%s'\n", c1->name, c0->name);
01206       memset(&ac0, 0, sizeof(ac0));
01207    } else {
01208       /* Store UDPTL peer */
01209       ast_udptl_get_peer(p0, &ac0);
01210    }
01211    ast_channel_unlock(c0);
01212    ast_channel_unlock(c1);
01213    cs[0] = c0;
01214    cs[1] = c1;
01215    cs[2] = NULL;
01216    for (;;) {
01217       if ((c0->tech_pvt != pvt0) ||
01218          (c1->tech_pvt != pvt1) ||
01219          (c0->masq || c0->masqr || c1->masq || c1->masqr)) {
01220             ast_debug(1, "Oooh, something is weird, backing out\n");
01221             /* Tell it to try again later */
01222             return -3;
01223       }
01224       to = -1;
01225       ast_udptl_get_peer(p1, &t1);
01226       ast_udptl_get_peer(p0, &t0);
01227       if (inaddrcmp(&t1, &ac1)) {
01228          ast_debug(1, "Oooh, '%s' changed end address to %s:%d\n", 
01229             c1->name, ast_inet_ntoa(t1.sin_addr), ntohs(t1.sin_port));
01230          ast_debug(1, "Oooh, '%s' was %s:%d\n", 
01231             c1->name, ast_inet_ntoa(ac1.sin_addr), ntohs(ac1.sin_port));
01232          memcpy(&ac1, &t1, sizeof(ac1));
01233       }
01234       if (inaddrcmp(&t0, &ac0)) {
01235          ast_debug(1, "Oooh, '%s' changed end address to %s:%d\n", 
01236             c0->name, ast_inet_ntoa(t0.sin_addr), ntohs(t0.sin_port));
01237          ast_debug(1, "Oooh, '%s' was %s:%d\n", 
01238             c0->name, ast_inet_ntoa(ac0.sin_addr), ntohs(ac0.sin_port));
01239          memcpy(&ac0, &t0, sizeof(ac0));
01240       }
01241       who = ast_waitfor_n(cs, 2, &to);
01242       if (!who) {
01243          ast_debug(1, "Ooh, empty read...\n");
01244          /* check for hangup / whentohangup */
01245          if (ast_check_hangup(c0) || ast_check_hangup(c1))
01246             break;
01247          continue;
01248       }
01249       f = ast_read(who);
01250       if (!f) {
01251          *fo = f;
01252          *rc = who;
01253          ast_debug(1, "Oooh, got a %s\n", f ? "digit" : "hangup");
01254          /* That's all we needed */
01255          return 0;
01256       } else {
01257          if (f->frametype == AST_FRAME_MODEM) {
01258             /* Forward T.38 frames if they happen upon us */
01259             if (who == c0) {
01260                ast_write(c1, f);
01261             } else if (who == c1) {
01262                ast_write(c0, f);
01263             }
01264          }
01265          ast_frfree(f);
01266       }
01267       /* Swap priority. Not that it's a big deal at this point */
01268       cs[2] = cs[0];
01269       cs[0] = cs[1];
01270       cs[1] = cs[2];
01271    }
01272    return -1;
01273 }
01274 
01275 static char *handle_cli_udptl_debug_deprecated(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
01276 {
01277    struct hostent *hp;
01278    struct ast_hostent ahp;
01279    int port;
01280    char *p;
01281    char *arg;
01282 
01283    switch (cmd) {
01284    case CLI_INIT:
01285       e->command = "udptl debug [off|ip]";
01286       e->usage = 
01287          "Usage: udptl debug [off]|[ip host[:port]]\n"
01288          "       Enable or disable dumping of UDPTL packets.\n"
01289          "       If ip is specified, limit the dumped packets to those to and from\n"
01290          "       the specified 'host' with optional port.\n";
01291       return NULL;
01292    case CLI_GENERATE:
01293       return NULL;
01294    }
01295 
01296    if (a->argc < 2 || a->argc > 4)
01297       return CLI_SHOWUSAGE;
01298 
01299    if (a->argc == 2) { 
01300       udptldebug = 1;
01301       memset(&udptldebugaddr, 0, sizeof(udptldebugaddr));
01302       ast_cli(a->fd, "UDPTL Debugging Enabled\n");
01303    } else if (a->argc == 3) {
01304       if (strncasecmp(a->argv[2], "off", 3))
01305          return CLI_SHOWUSAGE;
01306       udptldebug = 0;
01307       ast_cli(a->fd, "UDPTL Debugging Disabled\n");
01308    } else {
01309       if (strncasecmp(a->argv[2], "ip", 2))
01310          return CLI_SHOWUSAGE;
01311       port = 0;
01312       arg = a->argv[3];
01313       p = strstr(arg, ":");
01314       if (p) {
01315          *p = '\0';
01316          p++;
01317          port = atoi(p);
01318       }
01319       hp = ast_gethostbyname(arg, &ahp);
01320       if (hp == NULL)
01321          return CLI_SHOWUSAGE;
01322       udptldebugaddr.sin_family = AF_INET;
01323       memcpy(&udptldebugaddr.sin_addr, hp->h_addr, sizeof(udptldebugaddr.sin_addr));
01324       udptldebugaddr.sin_port = htons(port);
01325       if (port == 0)
01326          ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s\n", ast_inet_ntoa(udptldebugaddr.sin_addr));
01327       else
01328          ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s:%d\n", ast_inet_ntoa(udptldebugaddr.sin_addr), port);
01329       udptldebug = 1;
01330    }
01331 
01332    return CLI_SUCCESS;
01333 }
01334 
01335 static char *handle_cli_udptl_set_debug(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
01336 {
01337    struct hostent *hp;
01338    struct ast_hostent ahp;
01339    int port;
01340    char *p;
01341    char *arg;
01342 
01343    switch (cmd) {
01344    case CLI_INIT:
01345       e->command = "udptl set debug {on|off|ip}";
01346       e->usage = 
01347          "Usage: udptl set debug {on|off|ip host[:port]}\n"
01348          "       Enable or disable dumping of UDPTL packets.\n"
01349          "       If ip is specified, limit the dumped packets to those to and from\n"
01350          "       the specified 'host' with optional port.\n";
01351       return NULL;
01352    case CLI_GENERATE:
01353       return NULL;
01354    }
01355 
01356    if (a->argc < 4 || a->argc > 5)
01357       return CLI_SHOWUSAGE;
01358 
01359    if (a->argc == 4) {
01360       if (!strncasecmp(a->argv[3], "on", 2)) {
01361          udptldebug = 1;
01362          memset(&udptldebugaddr, 0, sizeof(udptldebugaddr));
01363          ast_cli(a->fd, "UDPTL Debugging Enabled\n");
01364       } else if (!strncasecmp(a->argv[3], "off", 3)) {
01365          udptldebug = 0;
01366          ast_cli(a->fd, "UDPTL Debugging Disabled\n");
01367       } else {
01368          return CLI_SHOWUSAGE;
01369       }
01370    } else {
01371       if (strncasecmp(a->argv[3], "ip", 2))
01372          return CLI_SHOWUSAGE;
01373       port = 0;
01374       arg = a->argv[4];
01375       p = strstr(arg, ":");
01376       if (p) {
01377          *p = '\0';
01378          p++;
01379          port = atoi(p);
01380       }
01381       hp = ast_gethostbyname(arg, &ahp);
01382       if (hp == NULL)
01383          return CLI_SHOWUSAGE;
01384       udptldebugaddr.sin_family = AF_INET;
01385       memcpy(&udptldebugaddr.sin_addr, hp->h_addr, sizeof(udptldebugaddr.sin_addr));
01386       udptldebugaddr.sin_port = htons(port);
01387       if (port == 0)
01388          ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s\n", ast_inet_ntoa(udptldebugaddr.sin_addr));
01389       else
01390          ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s:%d\n", ast_inet_ntoa(udptldebugaddr.sin_addr), port);
01391       udptldebug = 1;
01392    }
01393 
01394    return CLI_SUCCESS;
01395 }
01396 
01397 static struct ast_cli_entry cli_handle_udptl_debug_deprecated = AST_CLI_DEFINE(handle_cli_udptl_debug_deprecated, "Enable/Disable UDPTL debugging");
01398 
01399 static struct ast_cli_entry cli_udptl[] = {
01400    AST_CLI_DEFINE(handle_cli_udptl_set_debug, "Enable/Disable UDPTL debugging", .deprecate_cmd = &cli_handle_udptl_debug_deprecated)
01401 };
01402 
01403 static void __ast_udptl_reload(int reload)
01404 {
01405    struct ast_config *cfg;
01406    const char *s;
01407    struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
01408 
01409    if ((cfg = ast_config_load2("udptl.conf", "udptl", config_flags)) == CONFIG_STATUS_FILEUNCHANGED)
01410       return;
01411 
01412    udptlstart = 4500;
01413    udptlend = 4999;
01414    udptlfecentries = 0;
01415    udptlfecspan = 0;
01416    use_even_ports = 0;
01417 
01418    if (cfg) {
01419       if ((s = ast_variable_retrieve(cfg, "general", "udptlstart"))) {
01420          udptlstart = atoi(s);
01421          if (udptlstart < 1024) {
01422             ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
01423             udptlstart = 1024;
01424          }
01425          if (udptlstart > 65535) {
01426             ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
01427             udptlstart = 65535;
01428          }
01429       }
01430       if ((s = ast_variable_retrieve(cfg, "general", "udptlend"))) {
01431          udptlend = atoi(s);
01432          if (udptlend < 1024) {
01433             ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
01434             udptlend = 1024;
01435          }
01436          if (udptlend > 65535) {
01437             ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
01438             udptlend = 65535;
01439          }
01440       }
01441       if ((s = ast_variable_retrieve(cfg, "general", "udptlchecksums"))) {
01442 #ifdef SO_NO_CHECK
01443          if (ast_false(s))
01444             nochecksums = 1;
01445          else
01446             nochecksums = 0;
01447 #else
01448          if (ast_false(s))
01449             ast_log(LOG_WARNING, "Disabling UDPTL checksums is not supported on this operating system!\n");
01450 #endif
01451       }
01452       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxUdpEC"))) {
01453          ast_log(LOG_WARNING, "T38FaxUdpEC in udptl.conf is no longer supported; use the t38pt_udptl configuration option in sip.conf instead.\n");
01454       }
01455       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxMaxDatagram"))) {
01456          ast_log(LOG_WARNING, "T38FaxMaxDatagram in udptl.conf is no longer supported; value is now supplied by T.38 applications.\n");
01457       }
01458       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECEntries"))) {
01459          udptlfecentries = atoi(s);
01460          if (udptlfecentries < 1) {
01461             ast_log(LOG_WARNING, "Too small UDPTLFECEntries value.  Defaulting to 1.\n");
01462             udptlfecentries = 1;
01463          }
01464          if (udptlfecentries > MAX_FEC_ENTRIES) {
01465             ast_log(LOG_WARNING, "Too large UDPTLFECEntries value.  Defaulting to %d.\n", MAX_FEC_ENTRIES);
01466             udptlfecentries = MAX_FEC_ENTRIES;
01467          }
01468       }
01469       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECSpan"))) {
01470          udptlfecspan = atoi(s);
01471          if (udptlfecspan < 1) {
01472             ast_log(LOG_WARNING, "Too small UDPTLFECSpan value.  Defaulting to 1.\n");
01473             udptlfecspan = 1;
01474          }
01475          if (udptlfecspan > MAX_FEC_SPAN) {
01476             ast_log(LOG_WARNING, "Too large UDPTLFECSpan value.  Defaulting to %d.\n", MAX_FEC_SPAN);
01477             udptlfecspan = MAX_FEC_SPAN;
01478          }
01479       }
01480       if ((s = ast_variable_retrieve(cfg, "general", "use_even_ports"))) {
01481          use_even_ports = ast_true(s);
01482       }
01483       ast_config_destroy(cfg);
01484    }
01485    if (udptlstart >= udptlend) {
01486       ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end ports; defaulting to 4500-4999.\n");
01487       udptlstart = 4500;
01488       udptlend = 4999;
01489    }
01490    if (use_even_ports && (udptlstart & 1)) {
01491       ++udptlstart;
01492       ast_log(LOG_NOTICE, "Odd numbered udptlstart specified but use_even_ports enabled. udptlstart is now %d\n", udptlstart);
01493    }
01494    if (use_even_ports && (udptlend & 1)) {
01495       --udptlend;
01496       ast_log(LOG_NOTICE, "Odd numbered udptlend specified but use_event_ports enabled. udptlend is now %d\n", udptlend);
01497    }
01498    ast_verb(2, "UDPTL allocating from port range %d -> %d\n", udptlstart, udptlend);
01499 }
01500 
01501 int ast_udptl_reload(void)
01502 {
01503    __ast_udptl_reload(1);
01504    return 0;
01505 }
01506 
01507 void ast_udptl_init(void)
01508 {
01509    ast_cli_register_multiple(cli_udptl, sizeof(cli_udptl) / sizeof(struct ast_cli_entry));
01510    __ast_udptl_reload(0);
01511 }

Generated on Wed Aug 18 22:33:56 2010 for Asterisk - the Open Source PBX by  doxygen 1.4.7