Sat Mar 10 01:54:28 2012

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: 339625 $")
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 ast_sockaddr 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 ast_sockaddr us;
00125    struct ast_sockaddr 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    unsigned int tx_seq_no;
00174    unsigned int rx_seq_no;
00175 
00176    udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1];
00177    udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1];
00178 };
00179 
00180 static AST_RWLIST_HEAD_STATIC(protos, ast_udptl_protocol);
00181 
00182 static inline int udptl_debug_test_addr(const struct ast_sockaddr *addr)
00183 {
00184    if (udptldebug == 0)
00185       return 0;
00186 
00187    if (ast_sockaddr_isnull(&udptldebugaddr)) {
00188       return 1;
00189    }
00190 
00191    if (ast_sockaddr_port(&udptldebugaddr)) {
00192       return !ast_sockaddr_cmp(&udptldebugaddr, addr);
00193    } else {
00194       return !ast_sockaddr_cmp_addr(&udptldebugaddr, addr);
00195    }
00196 }
00197 
00198 static int decode_length(uint8_t *buf, unsigned int limit, unsigned int *len, unsigned int *pvalue)
00199 {
00200    if (*len >= limit)
00201       return -1;
00202    if ((buf[*len] & 0x80) == 0) {
00203       *pvalue = buf[*len];
00204       (*len)++;
00205       return 0;
00206    }
00207    if ((buf[*len] & 0x40) == 0) {
00208       if (*len == limit - 1)
00209          return -1;
00210       *pvalue = (buf[*len] & 0x3F) << 8;
00211       (*len)++;
00212       *pvalue |= buf[*len];
00213       (*len)++;
00214       return 0;
00215    }
00216    *pvalue = (buf[*len] & 0x3F) << 14;
00217    (*len)++;
00218    /* We have a fragment.  Currently we don't process fragments. */
00219    ast_debug(1, "UDPTL packet with length greater than 16K received, decoding will fail\n");
00220    return 1;
00221 }
00222 /*- End of function --------------------------------------------------------*/
00223 
00224 static int decode_open_type(uint8_t *buf, unsigned int limit, unsigned int *len, const uint8_t **p_object, unsigned int *p_num_octets)
00225 {
00226    unsigned int octet_cnt = 0;
00227 
00228    if (decode_length(buf, limit, len, &octet_cnt) != 0)
00229       return -1;
00230 
00231    if (octet_cnt > 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       *p_num_octets = octet_cnt;
00237       *p_object = &buf[*len];
00238       *len += octet_cnt;
00239    }
00240 
00241    return 0;
00242 }
00243 /*- End of function --------------------------------------------------------*/
00244 
00245 static unsigned int encode_length(uint8_t *buf, unsigned int *len, unsigned int value)
00246 {
00247    unsigned int multiplier;
00248 
00249    if (value < 0x80) {
00250       /* 1 octet */
00251       buf[*len] = value;
00252       (*len)++;
00253       return value;
00254    }
00255    if (value < 0x4000) {
00256       /* 2 octets */
00257       /* Set the first bit of the first octet */
00258       buf[*len] = ((0x8000 | value) >> 8) & 0xFF;
00259       (*len)++;
00260       buf[*len] = value & 0xFF;
00261       (*len)++;
00262       return value;
00263    }
00264    /* Fragmentation */
00265    multiplier = (value < 0x10000) ? (value >> 14) : 4;
00266    /* Set the first 2 bits of the octet */
00267    buf[*len] = 0xC0 | multiplier;
00268    (*len)++;
00269    return multiplier << 14;
00270 }
00271 /*- End of function --------------------------------------------------------*/
00272 
00273 static int encode_open_type(const struct ast_udptl *udptl, uint8_t *buf, unsigned int buflen,
00274              unsigned int *len, const uint8_t *data, unsigned int num_octets)
00275 {
00276    unsigned int enclen;
00277    unsigned 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 + *len > buflen) {
00291          ast_log(LOG_ERROR, "UDPTL (%s): Buffer overflow detected (%d + %d > %d)\n",
00292             LOG_TAG(udptl), enclen, *len, buflen);
00293          return -1;
00294       }
00295       if (enclen > 0) {
00296          memcpy(&buf[*len], &data[octet_idx], enclen);
00297          *len += enclen;
00298       }
00299       if (enclen >= num_octets)
00300          break;
00301    }
00302 
00303    return 0;
00304 }
00305 /*- End of function --------------------------------------------------------*/
00306 
00307 static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, unsigned int len)
00308 {
00309    int stat1;
00310    int stat2;
00311    int i;
00312    int j;
00313    int k;
00314    int l;
00315    int m;
00316    int x;
00317    int limit;
00318    int which;
00319    unsigned int ptr;
00320    unsigned int count;
00321    int total_count;
00322    int seq_no;
00323    const uint8_t *ifp = NULL;
00324    const uint8_t *data = NULL;
00325    unsigned int ifp_len = 0;
00326    int repaired[16];
00327    const uint8_t *bufs[ARRAY_LEN(s->f) - 1];
00328    unsigned int lengths[ARRAY_LEN(s->f) - 1];
00329    int span;
00330    int entries;
00331    int ifp_no;
00332 
00333    ptr = 0;
00334    ifp_no = 0;
00335    memset(&s->f[0], 0, sizeof(s->f[0]));
00336 
00337    /* Decode seq_number */
00338    if (ptr + 2 > len)
00339       return -1;
00340    seq_no = (buf[0] << 8) | buf[1];
00341    ptr += 2;
00342 
00343    /* Break out the primary packet */
00344    if ((stat1 = decode_open_type(buf, len, &ptr, &ifp, &ifp_len)) != 0)
00345       return -1;
00346    /* Decode error_recovery */
00347    if (ptr + 1 > len)
00348       return -1;
00349    if ((buf[ptr++] & 0x80) == 0) {
00350       /* Secondary packet mode for error recovery */
00351       if (seq_no > s->rx_seq_no) {
00352          /* We received a later packet than we expected, so we need to check if we can fill in the gap from the
00353             secondary packets. */
00354          total_count = 0;
00355          do {
00356             if ((stat2 = decode_length(buf, len, &ptr, &count)) < 0)
00357                return -1;
00358             for (i = 0; i < count && total_count + i < ARRAY_LEN(bufs); i++) {
00359                if ((stat1 = decode_open_type(buf, len, &ptr, &bufs[total_count + i], &lengths[total_count + i])) != 0)
00360                   return -1;
00361             }
00362             total_count += i;
00363          }
00364          while (stat2 > 0 && total_count < ARRAY_LEN(bufs));
00365          /* Step through in reverse order, so we go oldest to newest */
00366          for (i = total_count; i > 0; i--) {
00367             if (seq_no - i >= s->rx_seq_no) {
00368                /* This one wasn't seen before */
00369                /* Decode the secondary IFP packet */
00370                //fprintf(stderr, "Secondary %d, len %d\n", seq_no - i, lengths[i - 1]);
00371                s->f[ifp_no].frametype = AST_FRAME_MODEM;
00372                s->f[ifp_no].subclass.codec = AST_MODEM_T38;
00373 
00374                s->f[ifp_no].mallocd = 0;
00375                s->f[ifp_no].seqno = seq_no - i;
00376                s->f[ifp_no].datalen = lengths[i - 1];
00377                s->f[ifp_no].data.ptr = (uint8_t *) bufs[i - 1];
00378                s->f[ifp_no].offset = 0;
00379                s->f[ifp_no].src = "UDPTL";
00380                if (ifp_no > 0)
00381                   AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00382                AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00383                ifp_no++;
00384             }
00385          }
00386       }
00387    }
00388    else
00389    {
00390       /* FEC mode for error recovery */
00391       /* Our buffers cannot tolerate overlength IFP packets in FEC mode */
00392       if (ifp_len > LOCAL_FAX_MAX_DATAGRAM)
00393          return -1;
00394       /* Update any missed slots in the buffer */
00395       for ( ; seq_no > s->rx_seq_no; s->rx_seq_no++) {
00396          x = s->rx_seq_no & UDPTL_BUF_MASK;
00397          s->rx[x].buf_len = -1;
00398          s->rx[x].fec_len[0] = 0;
00399          s->rx[x].fec_span = 0;
00400          s->rx[x].fec_entries = 0;
00401       }
00402 
00403       x = seq_no & UDPTL_BUF_MASK;
00404 
00405       memset(repaired, 0, sizeof(repaired));
00406 
00407       /* Save the new IFP packet */
00408       memcpy(s->rx[x].buf, ifp, ifp_len);
00409       s->rx[x].buf_len = ifp_len;
00410       repaired[x] = TRUE;
00411 
00412       /* Decode the FEC packets */
00413       /* The span is defined as an unconstrained integer, but will never be more
00414          than a small value. */
00415       if (ptr + 2 > len)
00416          return -1;
00417       if (buf[ptr++] != 1)
00418          return -1;
00419       span = buf[ptr++];
00420       s->rx[x].fec_span = span;
00421 
00422       /* The number of entries is defined as a length, but will only ever be a small
00423          value. Treat it as such. */
00424       if (ptr + 1 > len)
00425          return -1;
00426       entries = buf[ptr++];
00427       if (entries > MAX_FEC_ENTRIES) {
00428          return -1;
00429       }
00430       s->rx[x].fec_entries = entries;
00431 
00432       /* Decode the elements */
00433       for (i = 0; i < entries; i++) {
00434          if ((stat1 = decode_open_type(buf, len, &ptr, &data, &s->rx[x].fec_len[i])) != 0)
00435             return -1;
00436          if (s->rx[x].fec_len[i] > LOCAL_FAX_MAX_DATAGRAM)
00437             return -1;
00438 
00439          /* Save the new FEC data */
00440          memcpy(s->rx[x].fec[i], data, s->rx[x].fec_len[i]);
00441 #if 0
00442          fprintf(stderr, "FEC: ");
00443          for (j = 0; j < s->rx[x].fec_len[i]; j++)
00444             fprintf(stderr, "%02X ", data[j]);
00445          fprintf(stderr, "\n");
00446 #endif
00447       }
00448 
00449       /* See if we can reconstruct anything which is missing */
00450       /* TODO: this does not comprehensively hunt back and repair everything that is possible */
00451       for (l = x; l != ((x - (16 - span*entries)) & UDPTL_BUF_MASK); l = (l - 1) & UDPTL_BUF_MASK) {
00452          if (s->rx[l].fec_len[0] <= 0)
00453             continue;
00454          for (m = 0; m < s->rx[l].fec_entries; m++) {
00455             limit = (l + m) & UDPTL_BUF_MASK;
00456             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) {
00457                if (s->rx[k].buf_len <= 0)
00458                   which = (which == -1) ? k : -2;
00459             }
00460             if (which >= 0) {
00461                /* Repairable */
00462                for (j = 0; j < s->rx[l].fec_len[m]; j++) {
00463                   s->rx[which].buf[j] = s->rx[l].fec[m][j];
00464                   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)
00465                      s->rx[which].buf[j] ^= (s->rx[k].buf_len > j) ? s->rx[k].buf[j] : 0;
00466                }
00467                s->rx[which].buf_len = s->rx[l].fec_len[m];
00468                repaired[which] = TRUE;
00469             }
00470          }
00471       }
00472       /* Now play any new packets forwards in time */
00473       for (l = (x + 1) & UDPTL_BUF_MASK, j = seq_no - UDPTL_BUF_MASK; l != x; l = (l + 1) & UDPTL_BUF_MASK, j++) {
00474          if (repaired[l]) {
00475             //fprintf(stderr, "Fixed packet %d, len %d\n", j, l);
00476             s->f[ifp_no].frametype = AST_FRAME_MODEM;
00477             s->f[ifp_no].subclass.codec = AST_MODEM_T38;
00478          
00479             s->f[ifp_no].mallocd = 0;
00480             s->f[ifp_no].seqno = j;
00481             s->f[ifp_no].datalen = s->rx[l].buf_len;
00482             s->f[ifp_no].data.ptr = s->rx[l].buf;
00483             s->f[ifp_no].offset = 0;
00484             s->f[ifp_no].src = "UDPTL";
00485             if (ifp_no > 0)
00486                AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00487             AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00488             ifp_no++;
00489          }
00490       }
00491    }
00492 
00493    /* If packets are received out of sequence, we may have already processed this packet from the error
00494       recovery information in a packet already received. */
00495    if (seq_no >= s->rx_seq_no) {
00496       /* Decode the primary IFP packet */
00497       s->f[ifp_no].frametype = AST_FRAME_MODEM;
00498       s->f[ifp_no].subclass.codec = AST_MODEM_T38;
00499       
00500       s->f[ifp_no].mallocd = 0;
00501       s->f[ifp_no].seqno = seq_no;
00502       s->f[ifp_no].datalen = ifp_len;
00503       s->f[ifp_no].data.ptr = (uint8_t *) ifp;
00504       s->f[ifp_no].offset = 0;
00505       s->f[ifp_no].src = "UDPTL";
00506       if (ifp_no > 0)
00507          AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00508       AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00509 
00510       ifp_no++;
00511    }
00512 
00513    s->rx_seq_no = seq_no + 1;
00514    return ifp_no;
00515 }
00516 /*- End of function --------------------------------------------------------*/
00517 
00518 static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, unsigned int buflen, uint8_t *ifp, unsigned int ifp_len)
00519 {
00520    uint8_t fec[LOCAL_FAX_MAX_DATAGRAM * 2];
00521    int i;
00522    int j;
00523    int seq;
00524    int entry;
00525    int entries;
00526    int span;
00527    int m;
00528    unsigned int len;
00529    int limit;
00530    int high_tide;
00531 
00532    seq = s->tx_seq_no & 0xFFFF;
00533 
00534    /* Map the sequence number to an entry in the circular buffer */
00535    entry = seq & UDPTL_BUF_MASK;
00536 
00537    /* We save the message in a circular buffer, for generating FEC or
00538       redundancy sets later on. */
00539    s->tx[entry].buf_len = ifp_len;
00540    memcpy(s->tx[entry].buf, ifp, ifp_len);
00541    
00542    /* Build the UDPTLPacket */
00543 
00544    len = 0;
00545    /* Encode the sequence number */
00546    buf[len++] = (seq >> 8) & 0xFF;
00547    buf[len++] = seq & 0xFF;
00548 
00549    /* Encode the primary IFP packet */
00550    if (encode_open_type(s, buf, buflen, &len, ifp, ifp_len) < 0)
00551       return -1;
00552 
00553    /* Encode the appropriate type of error recovery information */
00554    switch (s->error_correction_scheme)
00555    {
00556    case UDPTL_ERROR_CORRECTION_NONE:
00557       /* Encode the error recovery type */
00558       buf[len++] = 0x00;
00559       /* The number of entries will always be zero, so it is pointless allowing
00560          for the fragmented case here. */
00561       if (encode_length(buf, &len, 0) < 0)
00562          return -1;
00563       break;
00564    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00565       /* Encode the error recovery type */
00566       buf[len++] = 0x00;
00567       if (s->tx_seq_no > s->error_correction_entries)
00568          entries = s->error_correction_entries;
00569       else
00570          entries = s->tx_seq_no;
00571       /* The number of entries will always be small, so it is pointless allowing
00572          for the fragmented case here. */
00573       if (encode_length(buf, &len, entries) < 0)
00574          return -1;
00575       /* Encode the elements */
00576       for (i = 0; i < entries; i++) {
00577          j = (entry - i - 1) & UDPTL_BUF_MASK;
00578          if (encode_open_type(s, buf, buflen, &len, s->tx[j].buf, s->tx[j].buf_len) < 0) {
00579             ast_debug(1, "UDPTL (%s): Encoding failed at i=%d, j=%d\n",
00580                  LOG_TAG(s), i, j);
00581             return -1;
00582          }
00583       }
00584       break;
00585    case UDPTL_ERROR_CORRECTION_FEC:
00586       span = s->error_correction_span;
00587       entries = s->error_correction_entries;
00588       if (seq < s->error_correction_span*s->error_correction_entries) {
00589          /* In the initial stages, wind up the FEC smoothly */
00590          entries = seq/s->error_correction_span;
00591          if (seq < s->error_correction_span)
00592             span = 0;
00593       }
00594       /* Encode the error recovery type */
00595       buf[len++] = 0x80;
00596       /* Span is defined as an inconstrained integer, which it dumb. It will only
00597          ever be a small value. Treat it as such. */
00598       buf[len++] = 1;
00599       buf[len++] = span;
00600       /* The number of entries is defined as a length, but will only ever be a small
00601          value. Treat it as such. */
00602       buf[len++] = entries;
00603       for (m = 0; m < entries; m++) {
00604          /* Make an XOR'ed entry the maximum length */
00605          limit = (entry + m) & UDPTL_BUF_MASK;
00606          high_tide = 0;
00607          for (i = (limit - span*entries) & UDPTL_BUF_MASK; i != limit; i = (i + entries) & UDPTL_BUF_MASK) {
00608             if (high_tide < s->tx[i].buf_len) {
00609                for (j = 0; j < high_tide; j++)
00610                   fec[j] ^= s->tx[i].buf[j];
00611                for ( ; j < s->tx[i].buf_len; j++)
00612                   fec[j] = s->tx[i].buf[j];
00613                high_tide = s->tx[i].buf_len;
00614             } else {
00615                for (j = 0; j < s->tx[i].buf_len; j++)
00616                   fec[j] ^= s->tx[i].buf[j];
00617             }
00618          }
00619          if (encode_open_type(s, buf, buflen, &len, fec, high_tide) < 0)
00620             return -1;
00621       }
00622       break;
00623    }
00624 
00625    s->tx_seq_no++;
00626    return len;
00627 }
00628 
00629 int ast_udptl_fd(const struct ast_udptl *udptl)
00630 {
00631    return udptl->fd;
00632 }
00633 
00634 void ast_udptl_set_data(struct ast_udptl *udptl, void *data)
00635 {
00636    udptl->data = data;
00637 }
00638 
00639 void ast_udptl_set_callback(struct ast_udptl *udptl, ast_udptl_callback callback)
00640 {
00641    udptl->callback = callback;
00642 }
00643 
00644 void ast_udptl_setnat(struct ast_udptl *udptl, int nat)
00645 {
00646    udptl->nat = nat;
00647 }
00648 
00649 static int udptlread(int *id, int fd, short events, void *cbdata)
00650 {
00651    struct ast_udptl *udptl = cbdata;
00652    struct ast_frame *f;
00653 
00654    if ((f = ast_udptl_read(udptl))) {
00655       if (udptl->callback)
00656          udptl->callback(udptl, f, udptl->data);
00657    }
00658    return 1;
00659 }
00660 
00661 struct ast_frame *ast_udptl_read(struct ast_udptl *udptl)
00662 {
00663    int res;
00664    struct ast_sockaddr addr;
00665    uint8_t *buf;
00666 
00667    buf = udptl->rawdata + AST_FRIENDLY_OFFSET;
00668 
00669    /* Cache where the header will go */
00670    res = ast_recvfrom(udptl->fd,
00671          buf,
00672          sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET,
00673          0,
00674          &addr);
00675    if (res < 0) {
00676       if (errno != EAGAIN)
00677          ast_log(LOG_WARNING, "UDPTL (%s): read error: %s\n",
00678             LOG_TAG(udptl), strerror(errno));
00679       ast_assert(errno != EBADF);
00680       return &ast_null_frame;
00681    }
00682 
00683    /* Ignore if the other side hasn't been given an address yet. */
00684    if (ast_sockaddr_isnull(&udptl->them)) {
00685       return &ast_null_frame;
00686    }
00687 
00688    if (udptl->nat) {
00689       /* Send to whoever sent to us */
00690       if (ast_sockaddr_cmp(&udptl->them, &addr)) {
00691          ast_sockaddr_copy(&udptl->them, &addr);
00692          ast_debug(1, "UDPTL (%s): NAT, Using address %s\n",
00693               LOG_TAG(udptl), ast_sockaddr_stringify(&udptl->them));
00694       }
00695    }
00696 
00697    if (udptl_debug_test_addr(&addr)) {
00698       int seq_no;
00699 
00700       /* Decode sequence number just for verbose message. */
00701       if (res < 2) {
00702          /* Short packet. */
00703          seq_no = -1;
00704       } else {
00705          seq_no = (buf[0] << 8) | buf[1];
00706       }
00707 
00708       ast_verb(1, "UDPTL (%s): packet from %s (seq %d, len %d)\n",
00709          LOG_TAG(udptl), ast_sockaddr_stringify(&addr), seq_no, res);
00710    }
00711    if (udptl_rx_packet(udptl, buf, res) < 1) {
00712       return &ast_null_frame;
00713    }
00714 
00715    return &udptl->f[0];
00716 }
00717 
00718 static void calculate_local_max_datagram(struct ast_udptl *udptl)
00719 {
00720    unsigned int new_max = 0;
00721 
00722    if (udptl->local_max_ifp == -1) {
00723       ast_log(LOG_WARNING, "UDPTL (%s): Cannot calculate local_max_datagram before local_max_ifp has been set.\n",
00724          LOG_TAG(udptl));
00725       udptl->local_max_datagram = -1;
00726       return;
00727    }
00728 
00729    /* calculate the amount of space required to receive an IFP
00730     * of the maximum size supported by the application/endpoint
00731     * that we are delivering them to (local endpoint), and add
00732     * the amount of space required to support the selected
00733     * error correction mode
00734     */
00735    switch (udptl->error_correction_scheme) {
00736    case UDPTL_ERROR_CORRECTION_NONE:
00737       /* need room for sequence number, length indicator, redundancy
00738        * indicator and following length indicator
00739        */
00740       new_max = 5 + udptl->local_max_ifp;
00741       break;
00742    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00743       /* need room for sequence number, length indicators, plus
00744        * room for up to 3 redundancy packets
00745        */
00746       new_max = 5 + udptl->local_max_ifp + 2 + (3 * udptl->local_max_ifp);
00747       break;
00748    case UDPTL_ERROR_CORRECTION_FEC:
00749       /* need room for sequence number, length indicators and a
00750        * a single IFP of the maximum size expected
00751        */
00752       new_max = 5 + udptl->local_max_ifp + 4 + udptl->local_max_ifp;
00753       break;
00754    }
00755    /* add 5% extra space for insurance, but no larger than LOCAL_FAX_MAX_DATAGRAM */
00756    udptl->local_max_datagram = MIN(new_max * 1.05, LOCAL_FAX_MAX_DATAGRAM);
00757 }
00758 
00759 static void calculate_far_max_ifp(struct ast_udptl *udptl)
00760 {
00761    unsigned new_max = 0;
00762 
00763    if (udptl->far_max_datagram == -1) {
00764       ast_log(LOG_WARNING, "UDPTL (%s): Cannot calculate far_max_ifp before far_max_datagram has been set.\n",
00765          LOG_TAG(udptl));
00766       udptl->far_max_ifp = -1;
00767       return;
00768    }
00769 
00770    /* the goal here is to supply the local endpoint (application
00771     * or bridged channel) a maximum IFP value that will allow it
00772     * to effectively and efficiently transfer image data at its
00773     * selected bit rate, taking into account the selected error
00774     * correction mode, but without overrunning the far endpoint's
00775     * datagram buffer. this is complicated by the fact that some
00776     * far endpoints send us bogus (small) max datagram values,
00777     * which would result in either buffer overrun or no error
00778     * correction. we try to accomodate those, but if the supplied
00779     * value is too small to do so, we'll emit warning messages and
00780     * the user will have to use configuration options to override
00781     * the max datagram value supplied by the far endpoint.
00782     */
00783    switch (udptl->error_correction_scheme) {
00784    case UDPTL_ERROR_CORRECTION_NONE:
00785       /* need room for sequence number, length indicator, redundancy
00786        * indicator and following length indicator
00787        */
00788       new_max = udptl->far_max_datagram - 5;
00789       break;
00790    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00791       /* for this case, we'd like to send as many error correction entries
00792        * as possible (up to the number we're configured for), but we'll settle
00793        * for sending fewer if the configured number would cause the
00794        * calculated max IFP to be too small for effective operation
00795        *
00796        * need room for sequence number, length indicators and the
00797        * configured number of redundant packets
00798        *
00799        * note: we purposely don't allow error_correction_entries to drop to
00800        * zero in this loop; we'd rather send smaller IFPs (and thus reduce
00801        * the image data transfer rate) than sacrifice redundancy completely
00802        */
00803       for (;;) {
00804          new_max = (udptl->far_max_datagram - 8) / (udptl->error_correction_entries + 1);
00805 
00806          if ((new_max < 80) && (udptl->error_correction_entries > 1)) {
00807             /* the max ifp is not large enough, subtract an
00808              * error correction entry and calculate again
00809              * */
00810             --udptl->error_correction_entries;
00811          } else {
00812             break;
00813          }
00814       }
00815       break;
00816    case UDPTL_ERROR_CORRECTION_FEC:
00817       /* need room for sequence number, length indicators and a
00818        * a single IFP of the maximum size expected
00819        */
00820       new_max = (udptl->far_max_datagram - 10) / 2;
00821       break;
00822    }
00823    /* subtract 5% of space for insurance */
00824    udptl->far_max_ifp = new_max * 0.95;
00825 }
00826 
00827 enum ast_t38_ec_modes ast_udptl_get_error_correction_scheme(const struct ast_udptl *udptl)
00828 {
00829    return udptl->error_correction_scheme;
00830 }
00831 
00832 void ast_udptl_set_error_correction_scheme(struct ast_udptl *udptl, enum ast_t38_ec_modes ec)
00833 {
00834    udptl->error_correction_scheme = ec;
00835    switch (ec) {
00836    case UDPTL_ERROR_CORRECTION_FEC:
00837       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
00838       if (udptl->error_correction_entries == 0) {
00839          udptl->error_correction_entries = 3;
00840       }
00841       if (udptl->error_correction_span == 0) {
00842          udptl->error_correction_span = 3;
00843       }
00844       break;
00845    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00846       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
00847       if (udptl->error_correction_entries == 0) {
00848          udptl->error_correction_entries = 3;
00849       }
00850       break;
00851    default:
00852       /* nothing to do */
00853       break;
00854    };
00855    /* reset calculated values so they'll be computed again */
00856    udptl->local_max_datagram = -1;
00857    udptl->far_max_ifp = -1;
00858 }
00859 
00860 void ast_udptl_set_local_max_ifp(struct ast_udptl *udptl, unsigned int max_ifp)
00861 {
00862    /* make sure max_ifp is a positive value since a cast will take place when
00863     * when setting local_max_ifp */
00864    if ((signed int) max_ifp > 0) {
00865       udptl->local_max_ifp = max_ifp;
00866       /* reset calculated values so they'll be computed again */
00867       udptl->local_max_datagram = -1;
00868    }
00869 }
00870 
00871 unsigned int ast_udptl_get_local_max_datagram(struct ast_udptl *udptl)
00872 {
00873    if (udptl->local_max_datagram == -1) {
00874       calculate_local_max_datagram(udptl);
00875    }
00876 
00877    /* this function expects a unsigned value in return. */
00878    if (udptl->local_max_datagram < 0) {
00879       return 0;
00880    }
00881    return udptl->local_max_datagram;
00882 }
00883 
00884 void ast_udptl_set_far_max_datagram(struct ast_udptl *udptl, unsigned int max_datagram)
00885 {
00886    if (!max_datagram || (max_datagram > FAX_MAX_DATAGRAM_LIMIT)) {
00887       udptl->far_max_datagram = DEFAULT_FAX_MAX_DATAGRAM;
00888    } else {
00889       udptl->far_max_datagram = max_datagram;
00890    }
00891    /* reset calculated values so they'll be computed again */
00892    udptl->far_max_ifp = -1;
00893 }
00894 
00895 unsigned int ast_udptl_get_far_max_datagram(const struct ast_udptl *udptl)
00896 {
00897    if (udptl->far_max_datagram < 0) {
00898       return 0;
00899    }
00900    return udptl->far_max_datagram;
00901 }
00902 
00903 unsigned int ast_udptl_get_far_max_ifp(struct ast_udptl *udptl)
00904 {
00905    if (udptl->far_max_ifp == -1) {
00906       calculate_far_max_ifp(udptl);
00907    }
00908 
00909    if (udptl->far_max_ifp < 0) {
00910       return 0;
00911    }
00912    return udptl->far_max_ifp;
00913 }
00914 
00915 struct ast_udptl *ast_udptl_new_with_bindaddr(struct sched_context *sched, struct io_context *io, int callbackmode, struct ast_sockaddr *addr)
00916 {
00917    struct ast_udptl *udptl;
00918    int x;
00919    int startplace;
00920    int i;
00921    long int flags;
00922 
00923    if (!(udptl = ast_calloc(1, sizeof(*udptl))))
00924       return NULL;
00925 
00926    udptl->error_correction_span = udptlfecspan;
00927    udptl->error_correction_entries = udptlfecentries;
00928    
00929    udptl->far_max_datagram = -1;
00930    udptl->far_max_ifp = -1;
00931    udptl->local_max_ifp = -1;
00932    udptl->local_max_datagram = -1;
00933 
00934    for (i = 0; i <= UDPTL_BUF_MASK; i++) {
00935       udptl->rx[i].buf_len = -1;
00936       udptl->tx[i].buf_len = -1;
00937    }
00938 
00939    if ((udptl->fd = socket(ast_sockaddr_is_ipv6(addr) ?
00940                AF_INET6 : AF_INET, SOCK_DGRAM, 0)) < 0) {
00941       ast_free(udptl);
00942       ast_log(LOG_WARNING, "Unable to allocate socket: %s\n", strerror(errno));
00943       return NULL;
00944    }
00945    flags = fcntl(udptl->fd, F_GETFL);
00946    fcntl(udptl->fd, F_SETFL, flags | O_NONBLOCK);
00947 #ifdef SO_NO_CHECK
00948    if (nochecksums)
00949       setsockopt(udptl->fd, SOL_SOCKET, SO_NO_CHECK, &nochecksums, sizeof(nochecksums));
00950 #endif
00951    /* Find us a place */
00952    x = (udptlstart == udptlend) ? udptlstart : (ast_random() % (udptlend - udptlstart)) + udptlstart;
00953    if (use_even_ports && (x & 1)) {
00954       ++x;
00955    }
00956    startplace = x;
00957    for (;;) {
00958       ast_sockaddr_copy(&udptl->us, addr);
00959       ast_sockaddr_set_port(&udptl->us, x);
00960       if (ast_bind(udptl->fd, &udptl->us) == 0) {
00961          break;
00962       }
00963       if (errno != EADDRINUSE) {
00964          ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno));
00965          close(udptl->fd);
00966          ast_free(udptl);
00967          return NULL;
00968       }
00969       if (use_even_ports) {
00970          x += 2;
00971       } else {
00972          ++x;
00973       }
00974       if (x > udptlend)
00975          x = udptlstart;
00976       if (x == startplace) {
00977          ast_log(LOG_WARNING, "No UDPTL ports remaining\n");
00978          close(udptl->fd);
00979          ast_free(udptl);
00980          return NULL;
00981       }
00982    }
00983    if (io && sched && callbackmode) {
00984       /* Operate this one in a callback mode */
00985       udptl->sched = sched;
00986       udptl->io = io;
00987       udptl->ioid = ast_io_add(udptl->io, udptl->fd, udptlread, AST_IO_IN, udptl);
00988    }
00989    return udptl;
00990 }
00991 
00992 void ast_udptl_set_tag(struct ast_udptl *udptl, const char *format, ...)
00993 {
00994    va_list ap;
00995 
00996    ast_free(udptl->tag);
00997    udptl->tag = NULL;
00998    va_start(ap, format);
00999    if (ast_vasprintf(&udptl->tag, format, ap) == -1) {
01000       udptl->tag = NULL;
01001    }
01002    va_end(ap);
01003 }
01004 
01005 int ast_udptl_setqos(struct ast_udptl *udptl, unsigned int tos, unsigned int cos)
01006 {
01007    return ast_netsock_set_qos(udptl->fd, tos, cos, "UDPTL");
01008 }
01009 
01010 void ast_udptl_set_peer(struct ast_udptl *udptl, const struct ast_sockaddr *them)
01011 {
01012    ast_sockaddr_copy(&udptl->them, them);
01013 }
01014 
01015 void ast_udptl_get_peer(const struct ast_udptl *udptl, struct ast_sockaddr *them)
01016 {
01017    ast_sockaddr_copy(them, &udptl->them);
01018 }
01019 
01020 void ast_udptl_get_us(const struct ast_udptl *udptl, struct ast_sockaddr *us)
01021 {
01022    ast_sockaddr_copy(us, &udptl->us);
01023 }
01024 
01025 void ast_udptl_stop(struct ast_udptl *udptl)
01026 {
01027    ast_sockaddr_setnull(&udptl->them);
01028 }
01029 
01030 void ast_udptl_destroy(struct ast_udptl *udptl)
01031 {
01032    if (udptl->ioid)
01033       ast_io_remove(udptl->io, udptl->ioid);
01034    if (udptl->fd > -1)
01035       close(udptl->fd);
01036    if (udptl->tag)
01037       ast_free(udptl->tag);
01038    ast_free(udptl);
01039 }
01040 
01041 int ast_udptl_write(struct ast_udptl *s, struct ast_frame *f)
01042 {
01043    unsigned int seq;
01044    unsigned int len = f->datalen;
01045    int res;
01046    /* if no max datagram size is provided, use default value */
01047    const int bufsize = (s->far_max_datagram > 0) ? s->far_max_datagram : DEFAULT_FAX_MAX_DATAGRAM;
01048    uint8_t buf[bufsize];
01049 
01050    memset(buf, 0, sizeof(buf));
01051 
01052    /* If we have no peer, return immediately */
01053    if (ast_sockaddr_isnull(&s->them)) {
01054       return 0;
01055    }
01056 
01057    /* If there is no data length, return immediately */
01058    if (f->datalen == 0)
01059       return 0;
01060    
01061    if ((f->frametype != AST_FRAME_MODEM) ||
01062        (f->subclass.codec != AST_MODEM_T38)) {
01063       ast_log(LOG_WARNING, "UDPTL (%s): UDPTL can only send T.38 data.\n",
01064          LOG_TAG(s));
01065       return -1;
01066    }
01067 
01068    if (len > s->far_max_ifp) {
01069       ast_log(LOG_WARNING,
01070          "UDPTL (%s): UDPTL asked to send %d bytes of IFP when far end only prepared to accept %d bytes; data loss will occur."
01071          "You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.\n",
01072          LOG_TAG(s), len, s->far_max_ifp);
01073       len = s->far_max_ifp;
01074    }
01075 
01076    /* Save seq_no for debug output because udptl_build_packet increments it */
01077    seq = s->tx_seq_no & 0xFFFF;
01078 
01079    /* Cook up the UDPTL packet, with the relevant EC info. */
01080    len = udptl_build_packet(s, buf, sizeof(buf), f->data.ptr, len);
01081 
01082    if ((signed int) len > 0 && !ast_sockaddr_isnull(&s->them)) {
01083       if ((res = ast_sendto(s->fd, buf, len, 0, &s->them)) < 0)
01084          ast_log(LOG_NOTICE, "UDPTL (%s): Transmission error to %s: %s\n",
01085             LOG_TAG(s), ast_sockaddr_stringify(&s->them), strerror(errno));
01086       if (udptl_debug_test_addr(&s->them))
01087          ast_verb(1, "UDPTL (%s): packet to %s (seq %d, len %d)\n",
01088             LOG_TAG(s), ast_sockaddr_stringify(&s->them), seq, len);
01089    }
01090       
01091    return 0;
01092 }
01093 
01094 void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto)
01095 {
01096    AST_RWLIST_WRLOCK(&protos);
01097    AST_RWLIST_REMOVE(&protos, proto, list);
01098    AST_RWLIST_UNLOCK(&protos);
01099 }
01100 
01101 int ast_udptl_proto_register(struct ast_udptl_protocol *proto)
01102 {
01103    struct ast_udptl_protocol *cur;
01104 
01105    AST_RWLIST_WRLOCK(&protos);
01106    AST_RWLIST_TRAVERSE(&protos, cur, list) {
01107       if (cur->type == proto->type) {
01108          ast_log(LOG_WARNING, "Tried to register same protocol '%s' twice\n", cur->type);
01109          AST_RWLIST_UNLOCK(&protos);
01110          return -1;
01111       }
01112    }
01113    AST_RWLIST_INSERT_TAIL(&protos, proto, list);
01114    AST_RWLIST_UNLOCK(&protos);
01115    return 0;
01116 }
01117 
01118 static struct ast_udptl_protocol *get_proto(struct ast_channel *chan)
01119 {
01120    struct ast_udptl_protocol *cur = NULL;
01121 
01122    AST_RWLIST_RDLOCK(&protos);
01123    AST_RWLIST_TRAVERSE(&protos, cur, list) {
01124       if (cur->type == chan->tech->type)
01125          break;
01126    }
01127    AST_RWLIST_UNLOCK(&protos);
01128 
01129    return cur;
01130 }
01131 
01132 int ast_udptl_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc)
01133 {
01134    struct ast_frame *f;
01135    struct ast_channel *who;
01136    struct ast_channel *cs[3];
01137    struct ast_udptl *p0;
01138    struct ast_udptl *p1;
01139    struct ast_udptl_protocol *pr0;
01140    struct ast_udptl_protocol *pr1;
01141    struct ast_sockaddr ac0;
01142    struct ast_sockaddr ac1;
01143    struct ast_sockaddr t0;
01144    struct ast_sockaddr t1;
01145    void *pvt0;
01146    void *pvt1;
01147    int to;
01148    
01149    ast_channel_lock(c0);
01150    while (ast_channel_trylock(c1)) {
01151       ast_channel_unlock(c0);
01152       usleep(1);
01153       ast_channel_lock(c0);
01154    }
01155    pr0 = get_proto(c0);
01156    pr1 = get_proto(c1);
01157    if (!pr0) {
01158       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c0->name);
01159       ast_channel_unlock(c0);
01160       ast_channel_unlock(c1);
01161       return -1;
01162    }
01163    if (!pr1) {
01164       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c1->name);
01165       ast_channel_unlock(c0);
01166       ast_channel_unlock(c1);
01167       return -1;
01168    }
01169    pvt0 = c0->tech_pvt;
01170    pvt1 = c1->tech_pvt;
01171    p0 = pr0->get_udptl_info(c0);
01172    p1 = pr1->get_udptl_info(c1);
01173    if (!p0 || !p1) {
01174       /* Somebody doesn't want to play... */
01175       ast_channel_unlock(c0);
01176       ast_channel_unlock(c1);
01177       return -2;
01178    }
01179    if (pr0->set_udptl_peer(c0, p1)) {
01180       ast_log(LOG_WARNING, "Channel '%s' failed to talk to '%s'\n", c0->name, c1->name);
01181       memset(&ac1, 0, sizeof(ac1));
01182    } else {
01183       /* Store UDPTL peer */
01184       ast_udptl_get_peer(p1, &ac1);
01185    }
01186    if (pr1->set_udptl_peer(c1, p0)) {
01187       ast_log(LOG_WARNING, "Channel '%s' failed to talk back to '%s'\n", c1->name, c0->name);
01188       memset(&ac0, 0, sizeof(ac0));
01189    } else {
01190       /* Store UDPTL peer */
01191       ast_udptl_get_peer(p0, &ac0);
01192    }
01193    ast_channel_unlock(c0);
01194    ast_channel_unlock(c1);
01195    cs[0] = c0;
01196    cs[1] = c1;
01197    cs[2] = NULL;
01198    for (;;) {
01199       if ((c0->tech_pvt != pvt0) ||
01200          (c1->tech_pvt != pvt1) ||
01201          (c0->masq || c0->masqr || c1->masq || c1->masqr)) {
01202             ast_debug(1, "Oooh, something is weird, backing out\n");
01203             /* Tell it to try again later */
01204             return -3;
01205       }
01206       to = -1;
01207       ast_udptl_get_peer(p1, &t1);
01208       ast_udptl_get_peer(p0, &t0);
01209       if (ast_sockaddr_cmp(&t1, &ac1)) {
01210          ast_debug(1, "Oooh, '%s' changed end address to %s\n", 
01211             c1->name, ast_sockaddr_stringify(&t1));
01212          ast_debug(1, "Oooh, '%s' was %s\n", 
01213             c1->name, ast_sockaddr_stringify(&ac1));
01214          ast_sockaddr_copy(&ac1, &t1);
01215       }
01216       if (ast_sockaddr_cmp(&t0, &ac0)) {
01217          ast_debug(1, "Oooh, '%s' changed end address to %s\n", 
01218             c0->name, ast_sockaddr_stringify(&t0));
01219          ast_debug(1, "Oooh, '%s' was %s\n", 
01220             c0->name, ast_sockaddr_stringify(&ac0));
01221          ast_sockaddr_copy(&ac0, &t0);
01222       }
01223       who = ast_waitfor_n(cs, 2, &to);
01224       if (!who) {
01225          ast_debug(1, "Ooh, empty read...\n");
01226          /* check for hangup / whentohangup */
01227          if (ast_check_hangup(c0) || ast_check_hangup(c1))
01228             break;
01229          continue;
01230       }
01231       f = ast_read(who);
01232       if (!f) {
01233          *fo = f;
01234          *rc = who;
01235          ast_debug(1, "Oooh, got a %s\n", f ? "digit" : "hangup");
01236          /* That's all we needed */
01237          return 0;
01238       } else {
01239          if (f->frametype == AST_FRAME_MODEM) {
01240             /* Forward T.38 frames if they happen upon us */
01241             if (who == c0) {
01242                ast_write(c1, f);
01243             } else if (who == c1) {
01244                ast_write(c0, f);
01245             }
01246          }
01247          ast_frfree(f);
01248       }
01249       /* Swap priority. Not that it's a big deal at this point */
01250       cs[2] = cs[0];
01251       cs[0] = cs[1];
01252       cs[1] = cs[2];
01253    }
01254    return -1;
01255 }
01256 
01257 static char *handle_cli_udptl_set_debug(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
01258 {
01259    switch (cmd) {
01260    case CLI_INIT:
01261       e->command = "udptl set debug {on|off|ip}";
01262       e->usage = 
01263          "Usage: udptl set debug {on|off|ip host[:port]}\n"
01264          "       Enable or disable dumping of UDPTL packets.\n"
01265          "       If ip is specified, limit the dumped packets to those to and from\n"
01266          "       the specified 'host' with optional port.\n";
01267       return NULL;
01268    case CLI_GENERATE:
01269       return NULL;
01270    }
01271 
01272    if (a->argc < 4 || a->argc > 5)
01273       return CLI_SHOWUSAGE;
01274 
01275    if (a->argc == 4) {
01276       if (!strncasecmp(a->argv[3], "on", 2)) {
01277          udptldebug = 1;
01278          memset(&udptldebugaddr, 0, sizeof(udptldebugaddr));
01279          ast_cli(a->fd, "UDPTL Debugging Enabled\n");
01280       } else if (!strncasecmp(a->argv[3], "off", 3)) {
01281          udptldebug = 0;
01282          ast_cli(a->fd, "UDPTL Debugging Disabled\n");
01283       } else {
01284          return CLI_SHOWUSAGE;
01285       }
01286    } else {
01287       struct ast_sockaddr *addrs;
01288       if (strncasecmp(a->argv[3], "ip", 2))
01289          return CLI_SHOWUSAGE;
01290       if (!ast_sockaddr_resolve(&addrs, a->argv[4], 0, 0)) {
01291          return CLI_SHOWUSAGE;
01292       }
01293       ast_sockaddr_copy(&udptldebugaddr, &addrs[0]);
01294          ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s\n", ast_sockaddr_stringify(&udptldebugaddr));
01295       udptldebug = 1;
01296       ast_free(addrs);
01297    }
01298 
01299    return CLI_SUCCESS;
01300 }
01301 
01302 
01303 static struct ast_cli_entry cli_udptl[] = {
01304    AST_CLI_DEFINE(handle_cli_udptl_set_debug, "Enable/Disable UDPTL debugging")
01305 };
01306 
01307 static void __ast_udptl_reload(int reload)
01308 {
01309    struct ast_config *cfg;
01310    const char *s;
01311    struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
01312 
01313    cfg = ast_config_load2("udptl.conf", "udptl", config_flags);
01314    if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEUNCHANGED || cfg == CONFIG_STATUS_FILEINVALID) {
01315       return;
01316    }
01317 
01318    udptlstart = 4500;
01319    udptlend = 4999;
01320    udptlfecentries = 0;
01321    udptlfecspan = 0;
01322    use_even_ports = 0;
01323 
01324    if (cfg) {
01325       if ((s = ast_variable_retrieve(cfg, "general", "udptlstart"))) {
01326          udptlstart = atoi(s);
01327          if (udptlstart < 1024) {
01328             ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
01329             udptlstart = 1024;
01330          }
01331          if (udptlstart > 65535) {
01332             ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
01333             udptlstart = 65535;
01334          }
01335       }
01336       if ((s = ast_variable_retrieve(cfg, "general", "udptlend"))) {
01337          udptlend = atoi(s);
01338          if (udptlend < 1024) {
01339             ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
01340             udptlend = 1024;
01341          }
01342          if (udptlend > 65535) {
01343             ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
01344             udptlend = 65535;
01345          }
01346       }
01347       if ((s = ast_variable_retrieve(cfg, "general", "udptlchecksums"))) {
01348 #ifdef SO_NO_CHECK
01349          if (ast_false(s))
01350             nochecksums = 1;
01351          else
01352             nochecksums = 0;
01353 #else
01354          if (ast_false(s))
01355             ast_log(LOG_WARNING, "Disabling UDPTL checksums is not supported on this operating system!\n");
01356 #endif
01357       }
01358       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxUdpEC"))) {
01359          ast_log(LOG_WARNING, "T38FaxUdpEC in udptl.conf is no longer supported; use the t38pt_udptl configuration option in sip.conf instead.\n");
01360       }
01361       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxMaxDatagram"))) {
01362          ast_log(LOG_WARNING, "T38FaxMaxDatagram in udptl.conf is no longer supported; value is now supplied by T.38 applications.\n");
01363       }
01364       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECEntries"))) {
01365          udptlfecentries = atoi(s);
01366          if (udptlfecentries < 1) {
01367             ast_log(LOG_WARNING, "Too small UDPTLFECEntries value.  Defaulting to 1.\n");
01368             udptlfecentries = 1;
01369          }
01370          if (udptlfecentries > MAX_FEC_ENTRIES) {
01371             ast_log(LOG_WARNING, "Too large UDPTLFECEntries value.  Defaulting to %d.\n", MAX_FEC_ENTRIES);
01372             udptlfecentries = MAX_FEC_ENTRIES;
01373          }
01374       }
01375       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECSpan"))) {
01376          udptlfecspan = atoi(s);
01377          if (udptlfecspan < 1) {
01378             ast_log(LOG_WARNING, "Too small UDPTLFECSpan value.  Defaulting to 1.\n");
01379             udptlfecspan = 1;
01380          }
01381          if (udptlfecspan > MAX_FEC_SPAN) {
01382             ast_log(LOG_WARNING, "Too large UDPTLFECSpan value.  Defaulting to %d.\n", MAX_FEC_SPAN);
01383             udptlfecspan = MAX_FEC_SPAN;
01384          }
01385       }
01386       if ((s = ast_variable_retrieve(cfg, "general", "use_even_ports"))) {
01387          use_even_ports = ast_true(s);
01388       }
01389       ast_config_destroy(cfg);
01390    }
01391    if (udptlstart >= udptlend) {
01392       ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end ports; defaulting to 4500-4999.\n");
01393       udptlstart = 4500;
01394       udptlend = 4999;
01395    }
01396    if (use_even_ports && (udptlstart & 1)) {
01397       ++udptlstart;
01398       ast_log(LOG_NOTICE, "Odd numbered udptlstart specified but use_even_ports enabled. udptlstart is now %d\n", udptlstart);
01399    }
01400    if (use_even_ports && (udptlend & 1)) {
01401       --udptlend;
01402       ast_log(LOG_NOTICE, "Odd numbered udptlend specified but use_event_ports enabled. udptlend is now %d\n", udptlend);
01403    }
01404    ast_verb(2, "UDPTL allocating from port range %d -> %d\n", udptlstart, udptlend);
01405 }
01406 
01407 int ast_udptl_reload(void)
01408 {
01409    __ast_udptl_reload(1);
01410    return 0;
01411 }
01412 
01413 void ast_udptl_init(void)
01414 {
01415    ast_cli_register_multiple(cli_udptl, ARRAY_LEN(cli_udptl));
01416    __ast_udptl_reload(0);
01417 }

Generated on Sat Mar 10 01:54:28 2012 for Asterisk - The Open Source Telephony Project by  doxygen 1.4.7