Mon Jun 27 16:50:57 2011

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: 308416 $")
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    unsigned int rx_expected_seq_no;
00176 
00177    udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1];
00178    udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1];
00179 };
00180 
00181 static AST_RWLIST_HEAD_STATIC(protos, ast_udptl_protocol);
00182 
00183 static inline int udptl_debug_test_addr(const struct ast_sockaddr *addr)
00184 {
00185    if (udptldebug == 0)
00186       return 0;
00187 
00188    if (ast_sockaddr_isnull(&udptldebugaddr)) {
00189       return 1;
00190    }
00191 
00192    if (ast_sockaddr_port(&udptldebugaddr)) {
00193       return !ast_sockaddr_cmp(&udptldebugaddr, addr);
00194    } else {
00195       return !ast_sockaddr_cmp_addr(&udptldebugaddr, addr);
00196    }
00197 }
00198 
00199 static int decode_length(uint8_t *buf, unsigned int limit, unsigned int *len, unsigned int *pvalue)
00200 {
00201    if (*len >= limit)
00202       return -1;
00203    if ((buf[*len] & 0x80) == 0) {
00204       *pvalue = buf[*len];
00205       (*len)++;
00206       return 0;
00207    }
00208    if ((buf[*len] & 0x40) == 0) {
00209       if (*len == limit - 1)
00210          return -1;
00211       *pvalue = (buf[*len] & 0x3F) << 8;
00212       (*len)++;
00213       *pvalue |= buf[*len];
00214       (*len)++;
00215       return 0;
00216    }
00217    *pvalue = (buf[*len] & 0x3F) << 14;
00218    (*len)++;
00219    /* We have a fragment.  Currently we don't process fragments. */
00220    ast_debug(1, "UDPTL packet with length greater than 16K received, decoding will fail\n");
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 = 0;
00228 
00229    if (decode_length(buf, limit, len, &octet_cnt) != 0)
00230       return -1;
00231 
00232    if (octet_cnt > 0) {
00233       /* Make sure the buffer contains at least the number of bits requested */
00234       if ((*len + octet_cnt) > limit)
00235          return -1;
00236 
00237       *p_num_octets = octet_cnt;
00238       *p_object = &buf[*len];
00239       *len += octet_cnt;
00240    }
00241 
00242    return 0;
00243 }
00244 /*- End of function --------------------------------------------------------*/
00245 
00246 static unsigned int encode_length(uint8_t *buf, unsigned int *len, unsigned int value)
00247 {
00248    unsigned int multiplier;
00249 
00250    if (value < 0x80) {
00251       /* 1 octet */
00252       buf[*len] = value;
00253       (*len)++;
00254       return value;
00255    }
00256    if (value < 0x4000) {
00257       /* 2 octets */
00258       /* Set the first bit of the first octet */
00259       buf[*len] = ((0x8000 | value) >> 8) & 0xFF;
00260       (*len)++;
00261       buf[*len] = value & 0xFF;
00262       (*len)++;
00263       return value;
00264    }
00265    /* Fragmentation */
00266    multiplier = (value < 0x10000) ? (value >> 14) : 4;
00267    /* Set the first 2 bits of the octet */
00268    buf[*len] = 0xC0 | multiplier;
00269    (*len)++;
00270    return multiplier << 14;
00271 }
00272 /*- End of function --------------------------------------------------------*/
00273 
00274 static int encode_open_type(const struct ast_udptl *udptl, uint8_t *buf, unsigned int buflen,
00275              unsigned int *len, const uint8_t *data, unsigned int num_octets)
00276 {
00277    unsigned int enclen;
00278    unsigned int octet_idx;
00279    uint8_t zero_byte;
00280 
00281    /* If open type is of zero length, add a single zero byte (10.1) */
00282    if (num_octets == 0) {
00283       zero_byte = 0;
00284       data = &zero_byte;
00285       num_octets = 1;
00286    }
00287    /* Encode the open type */
00288    for (octet_idx = 0; ; num_octets -= enclen, octet_idx += enclen) {
00289       if ((enclen = encode_length(buf, len, num_octets)) < 0)
00290          return -1;
00291       if (enclen + *len > buflen) {
00292          ast_log(LOG_ERROR, "(%s): Buffer overflow detected (%d + %d > %d)\n",
00293             LOG_TAG(udptl), enclen, *len, buflen);
00294          return -1;
00295       }
00296       if (enclen > 0) {
00297          memcpy(&buf[*len], &data[octet_idx], enclen);
00298          *len += enclen;
00299       }
00300       if (enclen >= num_octets)
00301          break;
00302    }
00303 
00304    return 0;
00305 }
00306 /*- End of function --------------------------------------------------------*/
00307 
00308 static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, unsigned int len)
00309 {
00310    int stat1;
00311    int stat2;
00312    int i;
00313    int j;
00314    int k;
00315    int l;
00316    int m;
00317    int x;
00318    int limit;
00319    int which;
00320    unsigned int ptr;
00321    unsigned int count;
00322    int total_count;
00323    int seq_no;
00324    const uint8_t *ifp;
00325    const uint8_t *data;
00326    unsigned int ifp_len;
00327    int repaired[16];
00328    const uint8_t *bufs[ARRAY_LEN(s->f) - 1];
00329    unsigned int lengths[ARRAY_LEN(s->f) - 1];
00330    int span;
00331    int entries;
00332    int ifp_no;
00333 
00334    ptr = 0;
00335    ifp_no = 0;
00336    memset(&s->f[0], 0, sizeof(s->f[0]));
00337 
00338    /* Decode seq_number */
00339    if (ptr + 2 > len)
00340       return -1;
00341    seq_no = (buf[0] << 8) | buf[1];
00342    ptr += 2;
00343 
00344    /* Break out the primary packet */
00345    if ((stat1 = decode_open_type(buf, len, &ptr, &ifp, &ifp_len)) != 0)
00346       return -1;
00347    /* Decode error_recovery */
00348    if (ptr + 1 > len)
00349       return -1;
00350    if ((buf[ptr++] & 0x80) == 0) {
00351       /* Secondary packet mode for error recovery */
00352       if (seq_no > s->rx_seq_no) {
00353          /* We received a later packet than we expected, so we need to check if we can fill in the gap from the
00354             secondary packets. */
00355          total_count = 0;
00356          do {
00357             if ((stat2 = decode_length(buf, len, &ptr, &count)) < 0)
00358                return -1;
00359             for (i = 0; i < count && total_count + i < ARRAY_LEN(bufs); i++) {
00360                if ((stat1 = decode_open_type(buf, len, &ptr, &bufs[total_count + i], &lengths[total_count + i])) != 0)
00361                   return -1;
00362             }
00363             total_count += i;
00364          }
00365          while (stat2 > 0 && total_count < ARRAY_LEN(bufs));
00366          /* Step through in reverse order, so we go oldest to newest */
00367          for (i = total_count; i > 0; i--) {
00368             if (seq_no - i >= s->rx_seq_no) {
00369                /* This one wasn't seen before */
00370                /* Decode the secondary IFP packet */
00371                //fprintf(stderr, "Secondary %d, len %d\n", seq_no - i, lengths[i - 1]);
00372                s->f[ifp_no].frametype = AST_FRAME_MODEM;
00373                s->f[ifp_no].subclass.codec = AST_MODEM_T38;
00374 
00375                s->f[ifp_no].mallocd = 0;
00376                s->f[ifp_no].seqno = seq_no - i;
00377                s->f[ifp_no].datalen = lengths[i - 1];
00378                s->f[ifp_no].data.ptr = (uint8_t *) bufs[i - 1];
00379                s->f[ifp_no].offset = 0;
00380                s->f[ifp_no].src = "UDPTL";
00381                if (ifp_no > 0)
00382                   AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00383                AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00384                ifp_no++;
00385             }
00386          }
00387       }
00388    }
00389    else
00390    {
00391       /* FEC mode for error recovery */
00392       /* Our buffers cannot tolerate overlength IFP packets in FEC mode */
00393       if (ifp_len > LOCAL_FAX_MAX_DATAGRAM)
00394          return -1;
00395       /* Update any missed slots in the buffer */
00396       for ( ; seq_no > s->rx_seq_no; s->rx_seq_no++) {
00397          x = s->rx_seq_no & UDPTL_BUF_MASK;
00398          s->rx[x].buf_len = -1;
00399          s->rx[x].fec_len[0] = 0;
00400          s->rx[x].fec_span = 0;
00401          s->rx[x].fec_entries = 0;
00402       }
00403 
00404       x = seq_no & UDPTL_BUF_MASK;
00405 
00406       memset(repaired, 0, sizeof(repaired));
00407 
00408       /* Save the new IFP packet */
00409       memcpy(s->rx[x].buf, ifp, ifp_len);
00410       s->rx[x].buf_len = ifp_len;
00411       repaired[x] = TRUE;
00412 
00413       /* Decode the FEC packets */
00414       /* The span is defined as an unconstrained integer, but will never be more
00415          than a small value. */
00416       if (ptr + 2 > len)
00417          return -1;
00418       if (buf[ptr++] != 1)
00419          return -1;
00420       span = buf[ptr++];
00421       s->rx[x].fec_span = span;
00422 
00423       /* The number of entries is defined as a length, but will only ever be a small
00424          value. Treat it as such. */
00425       if (ptr + 1 > len)
00426          return -1;
00427       entries = buf[ptr++];
00428       if (entries > MAX_FEC_ENTRIES) {
00429          return -1;
00430       }
00431       s->rx[x].fec_entries = entries;
00432 
00433       /* Decode the elements */
00434       for (i = 0; i < entries; i++) {
00435          if ((stat1 = decode_open_type(buf, len, &ptr, &data, &s->rx[x].fec_len[i])) != 0)
00436             return -1;
00437          if (s->rx[x].fec_len[i] > LOCAL_FAX_MAX_DATAGRAM)
00438             return -1;
00439 
00440          /* Save the new FEC data */
00441          memcpy(s->rx[x].fec[i], data, s->rx[x].fec_len[i]);
00442 #if 0
00443          fprintf(stderr, "FEC: ");
00444          for (j = 0; j < s->rx[x].fec_len[i]; j++)
00445             fprintf(stderr, "%02X ", data[j]);
00446          fprintf(stderr, "\n");
00447 #endif
00448       }
00449 
00450       /* See if we can reconstruct anything which is missing */
00451       /* TODO: this does not comprehensively hunt back and repair everything that is possible */
00452       for (l = x; l != ((x - (16 - span*entries)) & UDPTL_BUF_MASK); l = (l - 1) & UDPTL_BUF_MASK) {
00453          if (s->rx[l].fec_len[0] <= 0)
00454             continue;
00455          for (m = 0; m < s->rx[l].fec_entries; m++) {
00456             limit = (l + m) & UDPTL_BUF_MASK;
00457             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) {
00458                if (s->rx[k].buf_len <= 0)
00459                   which = (which == -1) ? k : -2;
00460             }
00461             if (which >= 0) {
00462                /* Repairable */
00463                for (j = 0; j < s->rx[l].fec_len[m]; j++) {
00464                   s->rx[which].buf[j] = s->rx[l].fec[m][j];
00465                   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)
00466                      s->rx[which].buf[j] ^= (s->rx[k].buf_len > j) ? s->rx[k].buf[j] : 0;
00467                }
00468                s->rx[which].buf_len = s->rx[l].fec_len[m];
00469                repaired[which] = TRUE;
00470             }
00471          }
00472       }
00473       /* Now play any new packets forwards in time */
00474       for (l = (x + 1) & UDPTL_BUF_MASK, j = seq_no - UDPTL_BUF_MASK; l != x; l = (l + 1) & UDPTL_BUF_MASK, j++) {
00475          if (repaired[l]) {
00476             //fprintf(stderr, "Fixed packet %d, len %d\n", j, l);
00477             s->f[ifp_no].frametype = AST_FRAME_MODEM;
00478             s->f[ifp_no].subclass.codec = AST_MODEM_T38;
00479          
00480             s->f[ifp_no].mallocd = 0;
00481             s->f[ifp_no].seqno = j;
00482             s->f[ifp_no].datalen = s->rx[l].buf_len;
00483             s->f[ifp_no].data.ptr = s->rx[l].buf;
00484             s->f[ifp_no].offset = 0;
00485             s->f[ifp_no].src = "UDPTL";
00486             if (ifp_no > 0)
00487                AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00488             AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00489             ifp_no++;
00490          }
00491       }
00492    }
00493 
00494    /* If packets are received out of sequence, we may have already processed this packet from the error
00495       recovery information in a packet already received. */
00496    if (seq_no >= s->rx_seq_no) {
00497       /* Decode the primary IFP packet */
00498       s->f[ifp_no].frametype = AST_FRAME_MODEM;
00499       s->f[ifp_no].subclass.codec = AST_MODEM_T38;
00500       
00501       s->f[ifp_no].mallocd = 0;
00502       s->f[ifp_no].seqno = seq_no;
00503       s->f[ifp_no].datalen = ifp_len;
00504       s->f[ifp_no].data.ptr = (uint8_t *) ifp;
00505       s->f[ifp_no].offset = 0;
00506       s->f[ifp_no].src = "UDPTL";
00507       if (ifp_no > 0)
00508          AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no];
00509       AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL;
00510 
00511       ifp_no++;
00512    }
00513 
00514    s->rx_seq_no = seq_no + 1;
00515    return ifp_no;
00516 }
00517 /*- End of function --------------------------------------------------------*/
00518 
00519 static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, unsigned int buflen, uint8_t *ifp, unsigned int ifp_len)
00520 {
00521    uint8_t fec[LOCAL_FAX_MAX_DATAGRAM * 2];
00522    int i;
00523    int j;
00524    int seq;
00525    int entry;
00526    int entries;
00527    int span;
00528    int m;
00529    unsigned int len;
00530    int limit;
00531    int high_tide;
00532 
00533    seq = s->tx_seq_no & 0xFFFF;
00534 
00535    /* Map the sequence number to an entry in the circular buffer */
00536    entry = seq & UDPTL_BUF_MASK;
00537 
00538    /* We save the message in a circular buffer, for generating FEC or
00539       redundancy sets later on. */
00540    s->tx[entry].buf_len = ifp_len;
00541    memcpy(s->tx[entry].buf, ifp, ifp_len);
00542    
00543    /* Build the UDPTLPacket */
00544 
00545    len = 0;
00546    /* Encode the sequence number */
00547    buf[len++] = (seq >> 8) & 0xFF;
00548    buf[len++] = seq & 0xFF;
00549 
00550    /* Encode the primary IFP packet */
00551    if (encode_open_type(s, buf, buflen, &len, ifp, ifp_len) < 0)
00552       return -1;
00553 
00554    /* Encode the appropriate type of error recovery information */
00555    switch (s->error_correction_scheme)
00556    {
00557    case UDPTL_ERROR_CORRECTION_NONE:
00558       /* Encode the error recovery type */
00559       buf[len++] = 0x00;
00560       /* The number of entries will always be zero, so it is pointless allowing
00561          for the fragmented case here. */
00562       if (encode_length(buf, &len, 0) < 0)
00563          return -1;
00564       break;
00565    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00566       /* Encode the error recovery type */
00567       buf[len++] = 0x00;
00568       if (s->tx_seq_no > s->error_correction_entries)
00569          entries = s->error_correction_entries;
00570       else
00571          entries = s->tx_seq_no;
00572       /* The number of entries will always be small, so it is pointless allowing
00573          for the fragmented case here. */
00574       if (encode_length(buf, &len, entries) < 0)
00575          return -1;
00576       /* Encode the elements */
00577       for (i = 0; i < entries; i++) {
00578          j = (entry - i - 1) & UDPTL_BUF_MASK;
00579          if (encode_open_type(s, buf, buflen, &len, s->tx[j].buf, s->tx[j].buf_len) < 0) {
00580             ast_debug(1, "(%s): Encoding failed at i=%d, j=%d\n",
00581                  LOG_TAG(s), i, j);
00582             return -1;
00583          }
00584       }
00585       break;
00586    case UDPTL_ERROR_CORRECTION_FEC:
00587       span = s->error_correction_span;
00588       entries = s->error_correction_entries;
00589       if (seq < s->error_correction_span*s->error_correction_entries) {
00590          /* In the initial stages, wind up the FEC smoothly */
00591          entries = seq/s->error_correction_span;
00592          if (seq < s->error_correction_span)
00593             span = 0;
00594       }
00595       /* Encode the error recovery type */
00596       buf[len++] = 0x80;
00597       /* Span is defined as an inconstrained integer, which it dumb. It will only
00598          ever be a small value. Treat it as such. */
00599       buf[len++] = 1;
00600       buf[len++] = span;
00601       /* The number of entries is defined as a length, but will only ever be a small
00602          value. Treat it as such. */
00603       buf[len++] = entries;
00604       for (m = 0; m < entries; m++) {
00605          /* Make an XOR'ed entry the maximum length */
00606          limit = (entry + m) & UDPTL_BUF_MASK;
00607          high_tide = 0;
00608          for (i = (limit - span*entries) & UDPTL_BUF_MASK; i != limit; i = (i + entries) & UDPTL_BUF_MASK) {
00609             if (high_tide < s->tx[i].buf_len) {
00610                for (j = 0; j < high_tide; j++)
00611                   fec[j] ^= s->tx[i].buf[j];
00612                for ( ; j < s->tx[i].buf_len; j++)
00613                   fec[j] = s->tx[i].buf[j];
00614                high_tide = s->tx[i].buf_len;
00615             } else {
00616                for (j = 0; j < s->tx[i].buf_len; j++)
00617                   fec[j] ^= s->tx[i].buf[j];
00618             }
00619          }
00620          if (encode_open_type(s, buf, buflen, &len, fec, high_tide) < 0)
00621             return -1;
00622       }
00623       break;
00624    }
00625 
00626    s->tx_seq_no++;
00627    return len;
00628 }
00629 
00630 int ast_udptl_fd(const struct ast_udptl *udptl)
00631 {
00632    return udptl->fd;
00633 }
00634 
00635 void ast_udptl_set_data(struct ast_udptl *udptl, void *data)
00636 {
00637    udptl->data = data;
00638 }
00639 
00640 void ast_udptl_set_callback(struct ast_udptl *udptl, ast_udptl_callback callback)
00641 {
00642    udptl->callback = callback;
00643 }
00644 
00645 void ast_udptl_setnat(struct ast_udptl *udptl, int nat)
00646 {
00647    udptl->nat = nat;
00648 }
00649 
00650 static int udptlread(int *id, int fd, short events, void *cbdata)
00651 {
00652    struct ast_udptl *udptl = cbdata;
00653    struct ast_frame *f;
00654 
00655    if ((f = ast_udptl_read(udptl))) {
00656       if (udptl->callback)
00657          udptl->callback(udptl, f, udptl->data);
00658    }
00659    return 1;
00660 }
00661 
00662 struct ast_frame *ast_udptl_read(struct ast_udptl *udptl)
00663 {
00664    int res;
00665    struct ast_sockaddr addr;
00666    uint16_t seqno = 0;
00667    uint16_t *udptlheader;
00668    
00669    /* Cache where the header will go */
00670    res = ast_recvfrom(udptl->fd,
00671          udptl->rawdata + AST_FRIENDLY_OFFSET,
00672          sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET,
00673          0,
00674          &addr);
00675    udptlheader = (uint16_t *)(udptl->rawdata + AST_FRIENDLY_OFFSET);
00676    if (res < 0) {
00677       if (errno != EAGAIN)
00678          ast_log(LOG_WARNING, "(%s): UDPTL read error: %s\n",
00679             LOG_TAG(udptl), strerror(errno));
00680       ast_assert(errno != EBADF);
00681       return &ast_null_frame;
00682    }
00683 
00684    /* Ignore if the other side hasn't been given an address yet. */
00685    if (ast_sockaddr_isnull(&udptl->them)) {
00686       return &ast_null_frame;
00687    }
00688 
00689    if (udptl->nat) {
00690       /* Send to whoever sent to us */
00691       if (ast_sockaddr_cmp(&udptl->them, &addr)) {
00692          ast_sockaddr_copy(&udptl->them, &addr);
00693          ast_debug(1, "UDPTL NAT (%s): Using address %s\n",
00694               LOG_TAG(udptl), ast_sockaddr_stringify(&udptl->them));
00695       }
00696    }
00697 
00698    if (udptl_debug_test_addr(&addr)) {
00699       ast_verb(1, "UDPTL (%s): packet from %s (type %d, seq %d, len %d)\n",
00700           LOG_TAG(udptl), ast_sockaddr_stringify(&addr), 0, seqno, res);
00701    }
00702    if (udptl_rx_packet(udptl, udptl->rawdata + AST_FRIENDLY_OFFSET, res) < 1)
00703       return &ast_null_frame;
00704 
00705    return &udptl->f[0];
00706 }
00707 
00708 static void calculate_local_max_datagram(struct ast_udptl *udptl)
00709 {
00710    unsigned int new_max = 0;
00711 
00712    if (udptl->local_max_ifp == -1) {
00713       ast_log(LOG_WARNING, "(%s): Cannot calculate local_max_datagram before local_max_ifp has been set.\n",
00714          LOG_TAG(udptl));
00715       udptl->local_max_datagram = -1;
00716       return;
00717    }
00718 
00719    /* calculate the amount of space required to receive an IFP
00720     * of the maximum size supported by the application/endpoint
00721     * that we are delivering them to (local endpoint), and add
00722     * the amount of space required to support the selected
00723     * error correction mode
00724     */
00725    switch (udptl->error_correction_scheme) {
00726    case UDPTL_ERROR_CORRECTION_NONE:
00727       /* need room for sequence number, length indicator, redundancy
00728        * indicator and following length indicator
00729        */
00730       new_max = 5 + udptl->local_max_ifp;
00731       break;
00732    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00733       /* need room for sequence number, length indicators, plus
00734        * room for up to 3 redundancy packets
00735        */
00736       new_max = 5 + udptl->local_max_ifp + 2 + (3 * udptl->local_max_ifp);
00737       break;
00738    case UDPTL_ERROR_CORRECTION_FEC:
00739       /* need room for sequence number, length indicators and a
00740        * a single IFP of the maximum size expected
00741        */
00742       new_max = 5 + udptl->local_max_ifp + 4 + udptl->local_max_ifp;
00743       break;
00744    }
00745    /* add 5% extra space for insurance, but no larger than LOCAL_FAX_MAX_DATAGRAM */
00746    udptl->local_max_datagram = MIN(new_max * 1.05, LOCAL_FAX_MAX_DATAGRAM);
00747 }
00748 
00749 static void calculate_far_max_ifp(struct ast_udptl *udptl)
00750 {
00751    unsigned new_max = 0;
00752 
00753    if (udptl->far_max_datagram == -1) {
00754       ast_log(LOG_WARNING, "(%s): Cannot calculate far_max_ifp before far_max_datagram has been set.\n",
00755          LOG_TAG(udptl));
00756       udptl->far_max_ifp = -1;
00757       return;
00758    }
00759 
00760    /* the goal here is to supply the local endpoint (application
00761     * or bridged channel) a maximum IFP value that will allow it
00762     * to effectively and efficiently transfer image data at its
00763     * selected bit rate, taking into account the selected error
00764     * correction mode, but without overrunning the far endpoint's
00765     * datagram buffer. this is complicated by the fact that some
00766     * far endpoints send us bogus (small) max datagram values,
00767     * which would result in either buffer overrun or no error
00768     * correction. we try to accomodate those, but if the supplied
00769     * value is too small to do so, we'll emit warning messages and
00770     * the user will have to use configuration options to override
00771     * the max datagram value supplied by the far endpoint.
00772     */
00773    switch (udptl->error_correction_scheme) {
00774    case UDPTL_ERROR_CORRECTION_NONE:
00775       /* need room for sequence number, length indicator, redundancy
00776        * indicator and following length indicator
00777        */
00778       new_max = udptl->far_max_datagram - 5;
00779       break;
00780    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00781       /* for this case, we'd like to send as many error correction entries
00782        * as possible (up to the number we're configured for), but we'll settle
00783        * for sending fewer if the configured number would cause the
00784        * calculated max IFP to be too small for effective operation
00785        *
00786        * need room for sequence number, length indicators and the
00787        * configured number of redundant packets
00788        *
00789        * note: we purposely don't allow error_correction_entries to drop to
00790        * zero in this loop; we'd rather send smaller IFPs (and thus reduce
00791        * the image data transfer rate) than sacrifice redundancy completely
00792        */
00793       for (;;) {
00794          new_max = (udptl->far_max_datagram - 8) / (udptl->error_correction_entries + 1);
00795 
00796          if ((new_max < 80) && (udptl->error_correction_entries > 1)) {
00797             /* the max ifp is not large enough, subtract an
00798              * error correction entry and calculate again
00799              * */
00800             --udptl->error_correction_entries;
00801          } else {
00802             break;
00803          }
00804       }
00805       break;
00806    case UDPTL_ERROR_CORRECTION_FEC:
00807       /* need room for sequence number, length indicators and a
00808        * a single IFP of the maximum size expected
00809        */
00810       new_max = (udptl->far_max_datagram - 10) / 2;
00811       break;
00812    }
00813    /* subtract 5% of space for insurance */
00814    udptl->far_max_ifp = new_max * 0.95;
00815 }
00816 
00817 enum ast_t38_ec_modes ast_udptl_get_error_correction_scheme(const struct ast_udptl *udptl)
00818 {
00819    return udptl->error_correction_scheme;
00820 }
00821 
00822 void ast_udptl_set_error_correction_scheme(struct ast_udptl *udptl, enum ast_t38_ec_modes ec)
00823 {
00824    udptl->error_correction_scheme = ec;
00825    switch (ec) {
00826    case UDPTL_ERROR_CORRECTION_FEC:
00827       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC;
00828       if (udptl->error_correction_entries == 0) {
00829          udptl->error_correction_entries = 3;
00830       }
00831       if (udptl->error_correction_span == 0) {
00832          udptl->error_correction_span = 3;
00833       }
00834       break;
00835    case UDPTL_ERROR_CORRECTION_REDUNDANCY:
00836       udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY;
00837       if (udptl->error_correction_entries == 0) {
00838          udptl->error_correction_entries = 3;
00839       }
00840       break;
00841    default:
00842       /* nothing to do */
00843       break;
00844    };
00845    /* reset calculated values so they'll be computed again */
00846    udptl->local_max_datagram = -1;
00847    udptl->far_max_ifp = -1;
00848 }
00849 
00850 void ast_udptl_set_local_max_ifp(struct ast_udptl *udptl, unsigned int max_ifp)
00851 {
00852    /* make sure max_ifp is a positive value since a cast will take place when
00853     * when setting local_max_ifp */
00854    if ((signed int) max_ifp > 0) {
00855       udptl->local_max_ifp = max_ifp;
00856       /* reset calculated values so they'll be computed again */
00857       udptl->local_max_datagram = -1;
00858    }
00859 }
00860 
00861 unsigned int ast_udptl_get_local_max_datagram(struct ast_udptl *udptl)
00862 {
00863    if (udptl->local_max_datagram == -1) {
00864       calculate_local_max_datagram(udptl);
00865    }
00866 
00867    /* this function expects a unsigned value in return. */
00868    if (udptl->local_max_datagram < 0) {
00869       return 0;
00870    }
00871    return udptl->local_max_datagram;
00872 }
00873 
00874 void ast_udptl_set_far_max_datagram(struct ast_udptl *udptl, unsigned int max_datagram)
00875 {
00876    if (!max_datagram || (max_datagram > FAX_MAX_DATAGRAM_LIMIT)) {
00877       udptl->far_max_datagram = DEFAULT_FAX_MAX_DATAGRAM;
00878    } else {
00879       udptl->far_max_datagram = max_datagram;
00880    }
00881    /* reset calculated values so they'll be computed again */
00882    udptl->far_max_ifp = -1;
00883 }
00884 
00885 unsigned int ast_udptl_get_far_max_datagram(const struct ast_udptl *udptl)
00886 {
00887    if (udptl->far_max_datagram < 0) {
00888       return 0;
00889    }
00890    return udptl->far_max_datagram;
00891 }
00892 
00893 unsigned int ast_udptl_get_far_max_ifp(struct ast_udptl *udptl)
00894 {
00895    if (udptl->far_max_ifp == -1) {
00896       calculate_far_max_ifp(udptl);
00897    }
00898 
00899    if (udptl->far_max_ifp < 0) {
00900       return 0;
00901    }
00902    return udptl->far_max_ifp;
00903 }
00904 
00905 struct ast_udptl *ast_udptl_new_with_bindaddr(struct sched_context *sched, struct io_context *io, int callbackmode, struct ast_sockaddr *addr)
00906 {
00907    struct ast_udptl *udptl;
00908    int x;
00909    int startplace;
00910    int i;
00911    long int flags;
00912 
00913    if (!(udptl = ast_calloc(1, sizeof(*udptl))))
00914       return NULL;
00915 
00916    udptl->error_correction_span = udptlfecspan;
00917    udptl->error_correction_entries = udptlfecentries;
00918    
00919    udptl->far_max_datagram = -1;
00920    udptl->far_max_ifp = -1;
00921    udptl->local_max_ifp = -1;
00922    udptl->local_max_datagram = -1;
00923 
00924    for (i = 0; i <= UDPTL_BUF_MASK; i++) {
00925       udptl->rx[i].buf_len = -1;
00926       udptl->tx[i].buf_len = -1;
00927    }
00928 
00929    if ((udptl->fd = socket(ast_sockaddr_is_ipv6(addr) ?
00930                AF_INET6 : AF_INET, SOCK_DGRAM, 0)) < 0) {
00931       ast_free(udptl);
00932       ast_log(LOG_WARNING, "Unable to allocate socket: %s\n", strerror(errno));
00933       return NULL;
00934    }
00935    flags = fcntl(udptl->fd, F_GETFL);
00936    fcntl(udptl->fd, F_SETFL, flags | O_NONBLOCK);
00937 #ifdef SO_NO_CHECK
00938    if (nochecksums)
00939       setsockopt(udptl->fd, SOL_SOCKET, SO_NO_CHECK, &nochecksums, sizeof(nochecksums));
00940 #endif
00941    /* Find us a place */
00942    x = (udptlstart == udptlend) ? udptlstart : (ast_random() % (udptlend - udptlstart)) + udptlstart;
00943    if (use_even_ports && (x & 1)) {
00944       ++x;
00945    }
00946    startplace = x;
00947    for (;;) {
00948       ast_sockaddr_copy(&udptl->us, addr);
00949       ast_sockaddr_set_port(&udptl->us, x);
00950       if (ast_bind(udptl->fd, &udptl->us) == 0) {
00951          break;
00952       }
00953       if (errno != EADDRINUSE) {
00954          ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno));
00955          close(udptl->fd);
00956          ast_free(udptl);
00957          return NULL;
00958       }
00959       if (use_even_ports) {
00960          x += 2;
00961       } else {
00962          ++x;
00963       }
00964       if (x > udptlend)
00965          x = udptlstart;
00966       if (x == startplace) {
00967          ast_log(LOG_WARNING, "No UDPTL ports remaining\n");
00968          close(udptl->fd);
00969          ast_free(udptl);
00970          return NULL;
00971       }
00972    }
00973    if (io && sched && callbackmode) {
00974       /* Operate this one in a callback mode */
00975       udptl->sched = sched;
00976       udptl->io = io;
00977       udptl->ioid = ast_io_add(udptl->io, udptl->fd, udptlread, AST_IO_IN, udptl);
00978    }
00979    return udptl;
00980 }
00981 
00982 void ast_udptl_set_tag(struct ast_udptl *udptl, const char *format, ...)
00983 {
00984    va_list ap;
00985 
00986    if (udptl->tag) {
00987       ast_free(udptl->tag);
00988       udptl->tag = NULL;
00989    }
00990    va_start(ap, format);
00991    if (ast_vasprintf(&udptl->tag, format, ap) == -1) {
00992       udptl->tag = NULL;
00993    }
00994    va_end(ap);
00995 }
00996 
00997 int ast_udptl_setqos(struct ast_udptl *udptl, unsigned int tos, unsigned int cos)
00998 {
00999    return ast_netsock_set_qos(udptl->fd, tos, cos, "UDPTL");
01000 }
01001 
01002 void ast_udptl_set_peer(struct ast_udptl *udptl, const struct ast_sockaddr *them)
01003 {
01004    ast_sockaddr_copy(&udptl->them, them);
01005 }
01006 
01007 void ast_udptl_get_peer(const struct ast_udptl *udptl, struct ast_sockaddr *them)
01008 {
01009    ast_sockaddr_copy(them, &udptl->them);
01010 }
01011 
01012 void ast_udptl_get_us(const struct ast_udptl *udptl, struct ast_sockaddr *us)
01013 {
01014    ast_sockaddr_copy(us, &udptl->us);
01015 }
01016 
01017 void ast_udptl_stop(struct ast_udptl *udptl)
01018 {
01019    ast_sockaddr_setnull(&udptl->them);
01020 }
01021 
01022 void ast_udptl_destroy(struct ast_udptl *udptl)
01023 {
01024    if (udptl->ioid)
01025       ast_io_remove(udptl->io, udptl->ioid);
01026    if (udptl->fd > -1)
01027       close(udptl->fd);
01028    if (udptl->tag)
01029       ast_free(udptl->tag);
01030    ast_free(udptl);
01031 }
01032 
01033 int ast_udptl_write(struct ast_udptl *s, struct ast_frame *f)
01034 {
01035    unsigned int seq;
01036    unsigned int len = f->datalen;
01037    int res;
01038    /* if no max datagram size is provided, use default value */
01039    const int bufsize = (s->far_max_datagram > 0) ? s->far_max_datagram : DEFAULT_FAX_MAX_DATAGRAM;
01040    uint8_t buf[bufsize];
01041 
01042    memset(buf, 0, sizeof(buf));
01043 
01044    /* If we have no peer, return immediately */
01045    if (ast_sockaddr_isnull(&s->them)) {
01046       return 0;
01047    }
01048 
01049    /* If there is no data length, return immediately */
01050    if (f->datalen == 0)
01051       return 0;
01052    
01053    if ((f->frametype != AST_FRAME_MODEM) ||
01054        (f->subclass.codec != AST_MODEM_T38)) {
01055       ast_log(LOG_WARNING, "(%s): UDPTL can only send T.38 data.\n",
01056          LOG_TAG(s));
01057       return -1;
01058    }
01059 
01060    if (len > s->far_max_ifp) {
01061       ast_log(LOG_WARNING,
01062          "(%s): UDPTL asked to send %d bytes of IFP when far end only prepared to accept %d bytes; data loss will occur."
01063          "You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.\n",
01064          LOG_TAG(s), len, s->far_max_ifp);
01065       len = s->far_max_ifp;
01066    }
01067 
01068    /* Save seq_no for debug output because udptl_build_packet increments it */
01069    seq = s->tx_seq_no & 0xFFFF;
01070 
01071    /* Cook up the UDPTL packet, with the relevant EC info. */
01072    len = udptl_build_packet(s, buf, sizeof(buf), f->data.ptr, len);
01073 
01074    if ((signed int) len > 0 && !ast_sockaddr_isnull(&s->them)) {
01075       if ((res = ast_sendto(s->fd, buf, len, 0, &s->them)) < 0)
01076          ast_log(LOG_NOTICE, "(%s): UDPTL Transmission error to %s: %s\n",
01077             LOG_TAG(s), ast_sockaddr_stringify(&s->them), strerror(errno));
01078       if (udptl_debug_test_addr(&s->them))
01079          ast_verb(1, "UDPTL (%s): packet to %s (type %d, seq %d, len %d)\n",
01080              LOG_TAG(s), ast_sockaddr_stringify(&s->them), 0, seq, len);
01081    }
01082       
01083    return 0;
01084 }
01085 
01086 void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto)
01087 {
01088    AST_RWLIST_WRLOCK(&protos);
01089    AST_RWLIST_REMOVE(&protos, proto, list);
01090    AST_RWLIST_UNLOCK(&protos);
01091 }
01092 
01093 int ast_udptl_proto_register(struct ast_udptl_protocol *proto)
01094 {
01095    struct ast_udptl_protocol *cur;
01096 
01097    AST_RWLIST_WRLOCK(&protos);
01098    AST_RWLIST_TRAVERSE(&protos, cur, list) {
01099       if (cur->type == proto->type) {
01100          ast_log(LOG_WARNING, "Tried to register same protocol '%s' twice\n", cur->type);
01101          AST_RWLIST_UNLOCK(&protos);
01102          return -1;
01103       }
01104    }
01105    AST_RWLIST_INSERT_TAIL(&protos, proto, list);
01106    AST_RWLIST_UNLOCK(&protos);
01107    return 0;
01108 }
01109 
01110 static struct ast_udptl_protocol *get_proto(struct ast_channel *chan)
01111 {
01112    struct ast_udptl_protocol *cur = NULL;
01113 
01114    AST_RWLIST_RDLOCK(&protos);
01115    AST_RWLIST_TRAVERSE(&protos, cur, list) {
01116       if (cur->type == chan->tech->type)
01117          break;
01118    }
01119    AST_RWLIST_UNLOCK(&protos);
01120 
01121    return cur;
01122 }
01123 
01124 int ast_udptl_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc)
01125 {
01126    struct ast_frame *f;
01127    struct ast_channel *who;
01128    struct ast_channel *cs[3];
01129    struct ast_udptl *p0;
01130    struct ast_udptl *p1;
01131    struct ast_udptl_protocol *pr0;
01132    struct ast_udptl_protocol *pr1;
01133    struct ast_sockaddr ac0;
01134    struct ast_sockaddr ac1;
01135    struct ast_sockaddr t0;
01136    struct ast_sockaddr t1;
01137    void *pvt0;
01138    void *pvt1;
01139    int to;
01140    
01141    ast_channel_lock(c0);
01142    while (ast_channel_trylock(c1)) {
01143       ast_channel_unlock(c0);
01144       usleep(1);
01145       ast_channel_lock(c0);
01146    }
01147    pr0 = get_proto(c0);
01148    pr1 = get_proto(c1);
01149    if (!pr0) {
01150       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c0->name);
01151       ast_channel_unlock(c0);
01152       ast_channel_unlock(c1);
01153       return -1;
01154    }
01155    if (!pr1) {
01156       ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c1->name);
01157       ast_channel_unlock(c0);
01158       ast_channel_unlock(c1);
01159       return -1;
01160    }
01161    pvt0 = c0->tech_pvt;
01162    pvt1 = c1->tech_pvt;
01163    p0 = pr0->get_udptl_info(c0);
01164    p1 = pr1->get_udptl_info(c1);
01165    if (!p0 || !p1) {
01166       /* Somebody doesn't want to play... */
01167       ast_channel_unlock(c0);
01168       ast_channel_unlock(c1);
01169       return -2;
01170    }
01171    if (pr0->set_udptl_peer(c0, p1)) {
01172       ast_log(LOG_WARNING, "Channel '%s' failed to talk to '%s'\n", c0->name, c1->name);
01173       memset(&ac1, 0, sizeof(ac1));
01174    } else {
01175       /* Store UDPTL peer */
01176       ast_udptl_get_peer(p1, &ac1);
01177    }
01178    if (pr1->set_udptl_peer(c1, p0)) {
01179       ast_log(LOG_WARNING, "Channel '%s' failed to talk back to '%s'\n", c1->name, c0->name);
01180       memset(&ac0, 0, sizeof(ac0));
01181    } else {
01182       /* Store UDPTL peer */
01183       ast_udptl_get_peer(p0, &ac0);
01184    }
01185    ast_channel_unlock(c0);
01186    ast_channel_unlock(c1);
01187    cs[0] = c0;
01188    cs[1] = c1;
01189    cs[2] = NULL;
01190    for (;;) {
01191       if ((c0->tech_pvt != pvt0) ||
01192          (c1->tech_pvt != pvt1) ||
01193          (c0->masq || c0->masqr || c1->masq || c1->masqr)) {
01194             ast_debug(1, "Oooh, something is weird, backing out\n");
01195             /* Tell it to try again later */
01196             return -3;
01197       }
01198       to = -1;
01199       ast_udptl_get_peer(p1, &t1);
01200       ast_udptl_get_peer(p0, &t0);
01201       if (ast_sockaddr_cmp(&t1, &ac1)) {
01202          ast_debug(1, "Oooh, '%s' changed end address to %s\n", 
01203             c1->name, ast_sockaddr_stringify(&t1));
01204          ast_debug(1, "Oooh, '%s' was %s\n", 
01205             c1->name, ast_sockaddr_stringify(&ac1));
01206          ast_sockaddr_copy(&ac1, &t1);
01207       }
01208       if (ast_sockaddr_cmp(&t0, &ac0)) {
01209          ast_debug(1, "Oooh, '%s' changed end address to %s\n", 
01210             c0->name, ast_sockaddr_stringify(&t0));
01211          ast_debug(1, "Oooh, '%s' was %s\n", 
01212             c0->name, ast_sockaddr_stringify(&ac0));
01213          ast_sockaddr_copy(&ac0, &t0);
01214       }
01215       who = ast_waitfor_n(cs, 2, &to);
01216       if (!who) {
01217          ast_debug(1, "Ooh, empty read...\n");
01218          /* check for hangup / whentohangup */
01219          if (ast_check_hangup(c0) || ast_check_hangup(c1))
01220             break;
01221          continue;
01222       }
01223       f = ast_read(who);
01224       if (!f) {
01225          *fo = f;
01226          *rc = who;
01227          ast_debug(1, "Oooh, got a %s\n", f ? "digit" : "hangup");
01228          /* That's all we needed */
01229          return 0;
01230       } else {
01231          if (f->frametype == AST_FRAME_MODEM) {
01232             /* Forward T.38 frames if they happen upon us */
01233             if (who == c0) {
01234                ast_write(c1, f);
01235             } else if (who == c1) {
01236                ast_write(c0, f);
01237             }
01238          }
01239          ast_frfree(f);
01240       }
01241       /* Swap priority. Not that it's a big deal at this point */
01242       cs[2] = cs[0];
01243       cs[0] = cs[1];
01244       cs[1] = cs[2];
01245    }
01246    return -1;
01247 }
01248 
01249 static char *handle_cli_udptl_set_debug(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
01250 {
01251    switch (cmd) {
01252    case CLI_INIT:
01253       e->command = "udptl set debug {on|off|ip}";
01254       e->usage = 
01255          "Usage: udptl set debug {on|off|ip host[:port]}\n"
01256          "       Enable or disable dumping of UDPTL packets.\n"
01257          "       If ip is specified, limit the dumped packets to those to and from\n"
01258          "       the specified 'host' with optional port.\n";
01259       return NULL;
01260    case CLI_GENERATE:
01261       return NULL;
01262    }
01263 
01264    if (a->argc < 4 || a->argc > 5)
01265       return CLI_SHOWUSAGE;
01266 
01267    if (a->argc == 4) {
01268       if (!strncasecmp(a->argv[3], "on", 2)) {
01269          udptldebug = 1;
01270          memset(&udptldebugaddr, 0, sizeof(udptldebugaddr));
01271          ast_cli(a->fd, "UDPTL Debugging Enabled\n");
01272       } else if (!strncasecmp(a->argv[3], "off", 3)) {
01273          udptldebug = 0;
01274          ast_cli(a->fd, "UDPTL Debugging Disabled\n");
01275       } else {
01276          return CLI_SHOWUSAGE;
01277       }
01278    } else {
01279       struct ast_sockaddr *addrs;
01280       if (strncasecmp(a->argv[3], "ip", 2))
01281          return CLI_SHOWUSAGE;
01282       if (!ast_sockaddr_resolve(&addrs, a->argv[4], 0, 0)) {
01283          return CLI_SHOWUSAGE;
01284       }
01285       ast_sockaddr_copy(&udptldebugaddr, &addrs[0]);
01286          ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s\n", ast_sockaddr_stringify(&udptldebugaddr));
01287       udptldebug = 1;
01288       ast_free(addrs);
01289    }
01290 
01291    return CLI_SUCCESS;
01292 }
01293 
01294 
01295 static struct ast_cli_entry cli_udptl[] = {
01296    AST_CLI_DEFINE(handle_cli_udptl_set_debug, "Enable/Disable UDPTL debugging")
01297 };
01298 
01299 static void __ast_udptl_reload(int reload)
01300 {
01301    struct ast_config *cfg;
01302    const char *s;
01303    struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
01304 
01305    cfg = ast_config_load2("udptl.conf", "udptl", config_flags);
01306    if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEUNCHANGED || cfg == CONFIG_STATUS_FILEINVALID) {
01307       return;
01308    }
01309 
01310    udptlstart = 4500;
01311    udptlend = 4999;
01312    udptlfecentries = 0;
01313    udptlfecspan = 0;
01314    use_even_ports = 0;
01315 
01316    if (cfg) {
01317       if ((s = ast_variable_retrieve(cfg, "general", "udptlstart"))) {
01318          udptlstart = atoi(s);
01319          if (udptlstart < 1024) {
01320             ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
01321             udptlstart = 1024;
01322          }
01323          if (udptlstart > 65535) {
01324             ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
01325             udptlstart = 65535;
01326          }
01327       }
01328       if ((s = ast_variable_retrieve(cfg, "general", "udptlend"))) {
01329          udptlend = atoi(s);
01330          if (udptlend < 1024) {
01331             ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n");
01332             udptlend = 1024;
01333          }
01334          if (udptlend > 65535) {
01335             ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n");
01336             udptlend = 65535;
01337          }
01338       }
01339       if ((s = ast_variable_retrieve(cfg, "general", "udptlchecksums"))) {
01340 #ifdef SO_NO_CHECK
01341          if (ast_false(s))
01342             nochecksums = 1;
01343          else
01344             nochecksums = 0;
01345 #else
01346          if (ast_false(s))
01347             ast_log(LOG_WARNING, "Disabling UDPTL checksums is not supported on this operating system!\n");
01348 #endif
01349       }
01350       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxUdpEC"))) {
01351          ast_log(LOG_WARNING, "T38FaxUdpEC in udptl.conf is no longer supported; use the t38pt_udptl configuration option in sip.conf instead.\n");
01352       }
01353       if ((s = ast_variable_retrieve(cfg, "general", "T38FaxMaxDatagram"))) {
01354          ast_log(LOG_WARNING, "T38FaxMaxDatagram in udptl.conf is no longer supported; value is now supplied by T.38 applications.\n");
01355       }
01356       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECEntries"))) {
01357          udptlfecentries = atoi(s);
01358          if (udptlfecentries < 1) {
01359             ast_log(LOG_WARNING, "Too small UDPTLFECEntries value.  Defaulting to 1.\n");
01360             udptlfecentries = 1;
01361          }
01362          if (udptlfecentries > MAX_FEC_ENTRIES) {
01363             ast_log(LOG_WARNING, "Too large UDPTLFECEntries value.  Defaulting to %d.\n", MAX_FEC_ENTRIES);
01364             udptlfecentries = MAX_FEC_ENTRIES;
01365          }
01366       }
01367       if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECSpan"))) {
01368          udptlfecspan = atoi(s);
01369          if (udptlfecspan < 1) {
01370             ast_log(LOG_WARNING, "Too small UDPTLFECSpan value.  Defaulting to 1.\n");
01371             udptlfecspan = 1;
01372          }
01373          if (udptlfecspan > MAX_FEC_SPAN) {
01374             ast_log(LOG_WARNING, "Too large UDPTLFECSpan value.  Defaulting to %d.\n", MAX_FEC_SPAN);
01375             udptlfecspan = MAX_FEC_SPAN;
01376          }
01377       }
01378       if ((s = ast_variable_retrieve(cfg, "general", "use_even_ports"))) {
01379          use_even_ports = ast_true(s);
01380       }
01381       ast_config_destroy(cfg);
01382    }
01383    if (udptlstart >= udptlend) {
01384       ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end ports; defaulting to 4500-4999.\n");
01385       udptlstart = 4500;
01386       udptlend = 4999;
01387    }
01388    if (use_even_ports && (udptlstart & 1)) {
01389       ++udptlstart;
01390       ast_log(LOG_NOTICE, "Odd numbered udptlstart specified but use_even_ports enabled. udptlstart is now %d\n", udptlstart);
01391    }
01392    if (use_even_ports && (udptlend & 1)) {
01393       --udptlend;
01394       ast_log(LOG_NOTICE, "Odd numbered udptlend specified but use_event_ports enabled. udptlend is now %d\n", udptlend);
01395    }
01396    ast_verb(2, "UDPTL allocating from port range %d -> %d\n", udptlstart, udptlend);
01397 }
01398 
01399 int ast_udptl_reload(void)
01400 {
01401    __ast_udptl_reload(1);
01402    return 0;
01403 }
01404 
01405 void ast_udptl_init(void)
01406 {
01407    ast_cli_register_multiple(cli_udptl, ARRAY_LEN(cli_udptl));
01408    __ast_udptl_reload(0);
01409 }

Generated on Mon Jun 27 16:50:57 2011 for Asterisk - The Open Source Telephony Project by  doxygen 1.4.7