/* * Asterisk -- A telephony toolkit for Linux. * * UDPTL support for T.38 * * Copyright (C) 2005, Steve Underwood, partly based on RTP code which is * Copyright (C) 1999-2009, Digium, Inc. * * Steve Underwood * Kevin P. Fleming * * See http://www.asterisk.org for more information about * the Asterisk project. Please do not directly contact * any of the maintainers of this project for assistance; * the project provides a web site, mailing lists and IRC * channels for your use. * * This program is free software, distributed under the terms of * the GNU General Public License Version 2. See the LICENSE file * at the top of the source tree. * * A license has been granted to Digium (via disclaimer) for the use of * this code. */ /*! * \file * * \brief UDPTL support for T.38 faxing * * * \author Mark Spencer * \author Steve Underwood * \author Kevin P. Fleming * * \page T38fax_udptl T.38 support :: UDPTL * * Asterisk supports T.38 fax passthrough, origination and termination. It does * not support gateway operation. The only channel driver that supports T.38 at * this time is chan_sip. * * UDPTL is handled very much like RTP. It can be reinvited to go directly between * the endpoints, without involving Asterisk in the media stream. * * \b References: * - chan_sip.c * - udptl.c * - app_fax.c */ #include "asterisk.h" ASTERISK_FILE_VERSION(__FILE__, "$Revision$") #include #include #include #include "asterisk/udptl.h" #include "asterisk/frame.h" #include "asterisk/channel.h" #include "asterisk/acl.h" #include "asterisk/config.h" #include "asterisk/lock.h" #include "asterisk/utils.h" #include "asterisk/netsock.h" #include "asterisk/cli.h" #include "asterisk/unaligned.h" #define UDPTL_MTU 1200 #if !defined(FALSE) #define FALSE 0 #endif #if !defined(TRUE) #define TRUE (!FALSE) #endif #define LOG_TAG(u) S_OR(u->tag, "no tag") static int udptlstart = 4500; static int udptlend = 4599; static int udptldebug; /*!< Are we debugging? */ static struct ast_sockaddr udptldebugaddr; /*!< Debug packets to/from this host */ #ifdef SO_NO_CHECK static int nochecksums; #endif static int udptlfecentries; static int udptlfecspan; static int use_even_ports; #define LOCAL_FAX_MAX_DATAGRAM 1400 #define DEFAULT_FAX_MAX_DATAGRAM 400 #define FAX_MAX_DATAGRAM_LIMIT 1400 #define MAX_FEC_ENTRIES 5 #define MAX_FEC_SPAN 5 #define UDPTL_BUF_MASK 15 typedef struct { int buf_len; uint8_t buf[LOCAL_FAX_MAX_DATAGRAM]; } udptl_fec_tx_buffer_t; typedef struct { int buf_len; uint8_t buf[LOCAL_FAX_MAX_DATAGRAM]; unsigned int fec_len[MAX_FEC_ENTRIES]; uint8_t fec[MAX_FEC_ENTRIES][LOCAL_FAX_MAX_DATAGRAM]; unsigned int fec_span; unsigned int fec_entries; } udptl_fec_rx_buffer_t; /*! \brief Structure for an UDPTL session */ struct ast_udptl { int fd; char resp; struct ast_frame f[16]; unsigned char rawdata[8192 + AST_FRIENDLY_OFFSET]; unsigned int lasteventseqn; int nat; int flags; struct ast_sockaddr us; struct ast_sockaddr them; int *ioid; struct ast_sched_context *sched; struct io_context *io; void *data; char *tag; ast_udptl_callback callback; /*! This option indicates the error correction scheme used in transmitted UDPTL * packets and expected in received UDPTL packets. */ enum ast_t38_ec_modes error_correction_scheme; /*! This option indicates the number of error correction entries transmitted in * UDPTL packets and expected in received UDPTL packets. */ unsigned int error_correction_entries; /*! This option indicates the span of the error correction entries in transmitted * UDPTL packets (FEC only). */ unsigned int error_correction_span; /*! The maximum size UDPTL packet that can be accepted by * the remote device. */ int far_max_datagram; /*! The maximum size UDPTL packet that we are prepared to * accept, or -1 if it hasn't been calculated since the last * changes were applied to the UDPTL structure. */ int local_max_datagram; /*! The maximum IFP that can be submitted for sending * to the remote device. Calculated from far_max_datagram, * error_correction_scheme and error_correction_entries, * or -1 if it hasn't been calculated since the last * changes were applied to the UDPTL structure. */ int far_max_ifp; /*! The maximum IFP that the local endpoint is prepared * to accept. Along with error_correction_scheme and * error_correction_entries, used to calculate local_max_datagram. */ int local_max_ifp; unsigned int tx_seq_no; unsigned int rx_seq_no; unsigned int rx_expected_seq_no; udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1]; udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1]; }; static AST_RWLIST_HEAD_STATIC(protos, ast_udptl_protocol); static inline int udptl_debug_test_addr(const struct ast_sockaddr *addr) { if (udptldebug == 0) return 0; if (ast_sockaddr_isnull(&udptldebugaddr)) { return 1; } if (ast_sockaddr_port(&udptldebugaddr)) { return !ast_sockaddr_cmp(&udptldebugaddr, addr); } else { return !ast_sockaddr_cmp_addr(&udptldebugaddr, addr); } } static int decode_length(uint8_t *buf, unsigned int limit, unsigned int *len, unsigned int *pvalue) { if (*len >= limit) return -1; if ((buf[*len] & 0x80) == 0) { *pvalue = buf[*len]; (*len)++; return 0; } if ((buf[*len] & 0x40) == 0) { if (*len == limit - 1) return -1; *pvalue = (buf[*len] & 0x3F) << 8; (*len)++; *pvalue |= buf[*len]; (*len)++; return 0; } *pvalue = (buf[*len] & 0x3F) << 14; (*len)++; /* We have a fragment. Currently we don't process fragments. */ ast_debug(1, "UDPTL packet with length greater than 16K received, decoding will fail\n"); return 1; } /*- End of function --------------------------------------------------------*/ static int decode_open_type(uint8_t *buf, unsigned int limit, unsigned int *len, const uint8_t **p_object, unsigned int *p_num_octets) { unsigned int octet_cnt = 0; if (decode_length(buf, limit, len, &octet_cnt) != 0) return -1; if (octet_cnt > 0) { /* Make sure the buffer contains at least the number of bits requested */ if ((*len + octet_cnt) > limit) return -1; *p_num_octets = octet_cnt; *p_object = &buf[*len]; *len += octet_cnt; } return 0; } /*- End of function --------------------------------------------------------*/ static unsigned int encode_length(uint8_t *buf, unsigned int *len, unsigned int value) { unsigned int multiplier; if (value < 0x80) { /* 1 octet */ buf[*len] = value; (*len)++; return value; } if (value < 0x4000) { /* 2 octets */ /* Set the first bit of the first octet */ buf[*len] = ((0x8000 | value) >> 8) & 0xFF; (*len)++; buf[*len] = value & 0xFF; (*len)++; return value; } /* Fragmentation */ multiplier = (value < 0x10000) ? (value >> 14) : 4; /* Set the first 2 bits of the octet */ buf[*len] = 0xC0 | multiplier; (*len)++; return multiplier << 14; } /*- End of function --------------------------------------------------------*/ static int encode_open_type(const struct ast_udptl *udptl, uint8_t *buf, unsigned int buflen, unsigned int *len, const uint8_t *data, unsigned int num_octets) { unsigned int enclen; unsigned int octet_idx; uint8_t zero_byte; /* If open type is of zero length, add a single zero byte (10.1) */ if (num_octets == 0) { zero_byte = 0; data = &zero_byte; num_octets = 1; } /* Encode the open type */ for (octet_idx = 0; ; num_octets -= enclen, octet_idx += enclen) { if ((enclen = encode_length(buf, len, num_octets)) < 0) return -1; if (enclen + *len > buflen) { ast_log(LOG_ERROR, "(%s): Buffer overflow detected (%d + %d > %d)\n", LOG_TAG(udptl), enclen, *len, buflen); return -1; } if (enclen > 0) { memcpy(&buf[*len], &data[octet_idx], enclen); *len += enclen; } if (enclen >= num_octets) break; } return 0; } /*- End of function --------------------------------------------------------*/ static int udptl_rx_packet(struct ast_udptl *s, uint8_t *buf, unsigned int len) { int stat1; int stat2; int i; int j; int k; int l; int m; int x; int limit; int which; unsigned int ptr; unsigned int count; int total_count; int seq_no; const uint8_t *ifp = NULL; const uint8_t *data = NULL; unsigned int ifp_len = 0; int repaired[16]; const uint8_t *bufs[ARRAY_LEN(s->f) - 1]; unsigned int lengths[ARRAY_LEN(s->f) - 1]; int span; int entries; int ifp_no; ptr = 0; ifp_no = 0; memset(&s->f[0], 0, sizeof(s->f[0])); /* Decode seq_number */ if (ptr + 2 > len) return -1; seq_no = (buf[0] << 8) | buf[1]; ptr += 2; /* Break out the primary packet */ if ((stat1 = decode_open_type(buf, len, &ptr, &ifp, &ifp_len)) != 0) return -1; /* Decode error_recovery */ if (ptr + 1 > len) return -1; if ((buf[ptr++] & 0x80) == 0) { /* Secondary packet mode for error recovery */ if (seq_no > s->rx_seq_no) { /* We received a later packet than we expected, so we need to check if we can fill in the gap from the secondary packets. */ total_count = 0; do { if ((stat2 = decode_length(buf, len, &ptr, &count)) < 0) return -1; for (i = 0; i < count && total_count + i < ARRAY_LEN(bufs); i++) { if ((stat1 = decode_open_type(buf, len, &ptr, &bufs[total_count + i], &lengths[total_count + i])) != 0) return -1; } total_count += i; } while (stat2 > 0 && total_count < ARRAY_LEN(bufs)); /* Step through in reverse order, so we go oldest to newest */ for (i = total_count; i > 0; i--) { if (seq_no - i >= s->rx_seq_no) { /* This one wasn't seen before */ /* Decode the secondary IFP packet */ //fprintf(stderr, "Secondary %d, len %d\n", seq_no - i, lengths[i - 1]); s->f[ifp_no].frametype = AST_FRAME_MODEM; s->f[ifp_no].subclass.integer = AST_MODEM_T38; s->f[ifp_no].mallocd = 0; s->f[ifp_no].seqno = seq_no - i; s->f[ifp_no].datalen = lengths[i - 1]; s->f[ifp_no].data.ptr = (uint8_t *) bufs[i - 1]; s->f[ifp_no].offset = 0; s->f[ifp_no].src = "UDPTL"; if (ifp_no > 0) AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no]; AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL; ifp_no++; } } } } else { /* FEC mode for error recovery */ /* Our buffers cannot tolerate overlength IFP packets in FEC mode */ if (ifp_len > LOCAL_FAX_MAX_DATAGRAM) return -1; /* Update any missed slots in the buffer */ for ( ; seq_no > s->rx_seq_no; s->rx_seq_no++) { x = s->rx_seq_no & UDPTL_BUF_MASK; s->rx[x].buf_len = -1; s->rx[x].fec_len[0] = 0; s->rx[x].fec_span = 0; s->rx[x].fec_entries = 0; } x = seq_no & UDPTL_BUF_MASK; memset(repaired, 0, sizeof(repaired)); /* Save the new IFP packet */ memcpy(s->rx[x].buf, ifp, ifp_len); s->rx[x].buf_len = ifp_len; repaired[x] = TRUE; /* Decode the FEC packets */ /* The span is defined as an unconstrained integer, but will never be more than a small value. */ if (ptr + 2 > len) return -1; if (buf[ptr++] != 1) return -1; span = buf[ptr++]; s->rx[x].fec_span = span; /* The number of entries is defined as a length, but will only ever be a small value. Treat it as such. */ if (ptr + 1 > len) return -1; entries = buf[ptr++]; if (entries > MAX_FEC_ENTRIES) { return -1; } s->rx[x].fec_entries = entries; /* Decode the elements */ for (i = 0; i < entries; i++) { if ((stat1 = decode_open_type(buf, len, &ptr, &data, &s->rx[x].fec_len[i])) != 0) return -1; if (s->rx[x].fec_len[i] > LOCAL_FAX_MAX_DATAGRAM) return -1; /* Save the new FEC data */ memcpy(s->rx[x].fec[i], data, s->rx[x].fec_len[i]); #if 0 fprintf(stderr, "FEC: "); for (j = 0; j < s->rx[x].fec_len[i]; j++) fprintf(stderr, "%02X ", data[j]); fprintf(stderr, "\n"); #endif } /* See if we can reconstruct anything which is missing */ /* TODO: this does not comprehensively hunt back and repair everything that is possible */ for (l = x; l != ((x - (16 - span*entries)) & UDPTL_BUF_MASK); l = (l - 1) & UDPTL_BUF_MASK) { if (s->rx[l].fec_len[0] <= 0) continue; for (m = 0; m < s->rx[l].fec_entries; m++) { limit = (l + m) & UDPTL_BUF_MASK; 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) { if (s->rx[k].buf_len <= 0) which = (which == -1) ? k : -2; } if (which >= 0) { /* Repairable */ for (j = 0; j < s->rx[l].fec_len[m]; j++) { s->rx[which].buf[j] = s->rx[l].fec[m][j]; 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) s->rx[which].buf[j] ^= (s->rx[k].buf_len > j) ? s->rx[k].buf[j] : 0; } s->rx[which].buf_len = s->rx[l].fec_len[m]; repaired[which] = TRUE; } } } /* Now play any new packets forwards in time */ for (l = (x + 1) & UDPTL_BUF_MASK, j = seq_no - UDPTL_BUF_MASK; l != x; l = (l + 1) & UDPTL_BUF_MASK, j++) { if (repaired[l]) { //fprintf(stderr, "Fixed packet %d, len %d\n", j, l); s->f[ifp_no].frametype = AST_FRAME_MODEM; s->f[ifp_no].subclass.integer = AST_MODEM_T38; s->f[ifp_no].mallocd = 0; s->f[ifp_no].seqno = j; s->f[ifp_no].datalen = s->rx[l].buf_len; s->f[ifp_no].data.ptr = s->rx[l].buf; s->f[ifp_no].offset = 0; s->f[ifp_no].src = "UDPTL"; if (ifp_no > 0) AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no]; AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL; ifp_no++; } } } /* If packets are received out of sequence, we may have already processed this packet from the error recovery information in a packet already received. */ if (seq_no >= s->rx_seq_no) { /* Decode the primary IFP packet */ s->f[ifp_no].frametype = AST_FRAME_MODEM; s->f[ifp_no].subclass.integer = AST_MODEM_T38; s->f[ifp_no].mallocd = 0; s->f[ifp_no].seqno = seq_no; s->f[ifp_no].datalen = ifp_len; s->f[ifp_no].data.ptr = (uint8_t *) ifp; s->f[ifp_no].offset = 0; s->f[ifp_no].src = "UDPTL"; if (ifp_no > 0) AST_LIST_NEXT(&s->f[ifp_no - 1], frame_list) = &s->f[ifp_no]; AST_LIST_NEXT(&s->f[ifp_no], frame_list) = NULL; ifp_no++; } s->rx_seq_no = seq_no + 1; return ifp_no; } /*- End of function --------------------------------------------------------*/ static int udptl_build_packet(struct ast_udptl *s, uint8_t *buf, unsigned int buflen, uint8_t *ifp, unsigned int ifp_len) { uint8_t fec[LOCAL_FAX_MAX_DATAGRAM * 2]; int i; int j; int seq; int entry; int entries; int span; int m; unsigned int len; int limit; int high_tide; seq = s->tx_seq_no & 0xFFFF; /* Map the sequence number to an entry in the circular buffer */ entry = seq & UDPTL_BUF_MASK; /* We save the message in a circular buffer, for generating FEC or redundancy sets later on. */ s->tx[entry].buf_len = ifp_len; memcpy(s->tx[entry].buf, ifp, ifp_len); /* Build the UDPTLPacket */ len = 0; /* Encode the sequence number */ buf[len++] = (seq >> 8) & 0xFF; buf[len++] = seq & 0xFF; /* Encode the primary IFP packet */ if (encode_open_type(s, buf, buflen, &len, ifp, ifp_len) < 0) return -1; /* Encode the appropriate type of error recovery information */ switch (s->error_correction_scheme) { case UDPTL_ERROR_CORRECTION_NONE: /* Encode the error recovery type */ buf[len++] = 0x00; /* The number of entries will always be zero, so it is pointless allowing for the fragmented case here. */ if (encode_length(buf, &len, 0) < 0) return -1; break; case UDPTL_ERROR_CORRECTION_REDUNDANCY: /* Encode the error recovery type */ buf[len++] = 0x00; if (s->tx_seq_no > s->error_correction_entries) entries = s->error_correction_entries; else entries = s->tx_seq_no; /* The number of entries will always be small, so it is pointless allowing for the fragmented case here. */ if (encode_length(buf, &len, entries) < 0) return -1; /* Encode the elements */ for (i = 0; i < entries; i++) { j = (entry - i - 1) & UDPTL_BUF_MASK; if (encode_open_type(s, buf, buflen, &len, s->tx[j].buf, s->tx[j].buf_len) < 0) { ast_debug(1, "(%s): Encoding failed at i=%d, j=%d\n", LOG_TAG(s), i, j); return -1; } } break; case UDPTL_ERROR_CORRECTION_FEC: span = s->error_correction_span; entries = s->error_correction_entries; if (seq < s->error_correction_span*s->error_correction_entries) { /* In the initial stages, wind up the FEC smoothly */ entries = seq/s->error_correction_span; if (seq < s->error_correction_span) span = 0; } /* Encode the error recovery type */ buf[len++] = 0x80; /* Span is defined as an inconstrained integer, which it dumb. It will only ever be a small value. Treat it as such. */ buf[len++] = 1; buf[len++] = span; /* The number of entries is defined as a length, but will only ever be a small value. Treat it as such. */ buf[len++] = entries; for (m = 0; m < entries; m++) { /* Make an XOR'ed entry the maximum length */ limit = (entry + m) & UDPTL_BUF_MASK; high_tide = 0; for (i = (limit - span*entries) & UDPTL_BUF_MASK; i != limit; i = (i + entries) & UDPTL_BUF_MASK) { if (high_tide < s->tx[i].buf_len) { for (j = 0; j < high_tide; j++) fec[j] ^= s->tx[i].buf[j]; for ( ; j < s->tx[i].buf_len; j++) fec[j] = s->tx[i].buf[j]; high_tide = s->tx[i].buf_len; } else { for (j = 0; j < s->tx[i].buf_len; j++) fec[j] ^= s->tx[i].buf[j]; } } if (encode_open_type(s, buf, buflen, &len, fec, high_tide) < 0) return -1; } break; } s->tx_seq_no++; return len; } int ast_udptl_fd(const struct ast_udptl *udptl) { return udptl->fd; } void ast_udptl_set_data(struct ast_udptl *udptl, void *data) { udptl->data = data; } void ast_udptl_set_callback(struct ast_udptl *udptl, ast_udptl_callback callback) { udptl->callback = callback; } void ast_udptl_setnat(struct ast_udptl *udptl, int nat) { udptl->nat = nat; } static int udptlread(int *id, int fd, short events, void *cbdata) { struct ast_udptl *udptl = cbdata; struct ast_frame *f; if ((f = ast_udptl_read(udptl))) { if (udptl->callback) udptl->callback(udptl, f, udptl->data); } return 1; } struct ast_frame *ast_udptl_read(struct ast_udptl *udptl) { int res; struct ast_sockaddr addr; uint16_t seqno = 0; /* Cache where the header will go */ res = ast_recvfrom(udptl->fd, udptl->rawdata + AST_FRIENDLY_OFFSET, sizeof(udptl->rawdata) - AST_FRIENDLY_OFFSET, 0, &addr); if (res < 0) { if (errno != EAGAIN) ast_log(LOG_WARNING, "(%s): UDPTL read error: %s\n", LOG_TAG(udptl), strerror(errno)); ast_assert(errno != EBADF); return &ast_null_frame; } /* Ignore if the other side hasn't been given an address yet. */ if (ast_sockaddr_isnull(&udptl->them)) { return &ast_null_frame; } if (udptl->nat) { /* Send to whoever sent to us */ if (ast_sockaddr_cmp(&udptl->them, &addr)) { ast_sockaddr_copy(&udptl->them, &addr); ast_debug(1, "UDPTL NAT (%s): Using address %s\n", LOG_TAG(udptl), ast_sockaddr_stringify(&udptl->them)); } } if (udptl_debug_test_addr(&addr)) { ast_verb(1, "UDPTL (%s): packet from %s (type %d, seq %d, len %d)\n", LOG_TAG(udptl), ast_sockaddr_stringify(&addr), 0, seqno, res); } if (udptl_rx_packet(udptl, udptl->rawdata + AST_FRIENDLY_OFFSET, res) < 1) return &ast_null_frame; return &udptl->f[0]; } static void calculate_local_max_datagram(struct ast_udptl *udptl) { unsigned int new_max = 0; if (udptl->local_max_ifp == -1) { ast_log(LOG_WARNING, "(%s): Cannot calculate local_max_datagram before local_max_ifp has been set.\n", LOG_TAG(udptl)); udptl->local_max_datagram = -1; return; } /* calculate the amount of space required to receive an IFP * of the maximum size supported by the application/endpoint * that we are delivering them to (local endpoint), and add * the amount of space required to support the selected * error correction mode */ switch (udptl->error_correction_scheme) { case UDPTL_ERROR_CORRECTION_NONE: /* need room for sequence number, length indicator, redundancy * indicator and following length indicator */ new_max = 5 + udptl->local_max_ifp; break; case UDPTL_ERROR_CORRECTION_REDUNDANCY: /* need room for sequence number, length indicators, plus * room for up to 3 redundancy packets */ new_max = 5 + udptl->local_max_ifp + 2 + (3 * udptl->local_max_ifp); break; case UDPTL_ERROR_CORRECTION_FEC: /* need room for sequence number, length indicators and a * a single IFP of the maximum size expected */ new_max = 5 + udptl->local_max_ifp + 4 + udptl->local_max_ifp; break; } /* add 5% extra space for insurance, but no larger than LOCAL_FAX_MAX_DATAGRAM */ udptl->local_max_datagram = MIN(new_max * 1.05, LOCAL_FAX_MAX_DATAGRAM); } static void calculate_far_max_ifp(struct ast_udptl *udptl) { unsigned new_max = 0; if (udptl->far_max_datagram == -1) { ast_log(LOG_WARNING, "(%s): Cannot calculate far_max_ifp before far_max_datagram has been set.\n", LOG_TAG(udptl)); udptl->far_max_ifp = -1; return; } /* the goal here is to supply the local endpoint (application * or bridged channel) a maximum IFP value that will allow it * to effectively and efficiently transfer image data at its * selected bit rate, taking into account the selected error * correction mode, but without overrunning the far endpoint's * datagram buffer. this is complicated by the fact that some * far endpoints send us bogus (small) max datagram values, * which would result in either buffer overrun or no error * correction. we try to accomodate those, but if the supplied * value is too small to do so, we'll emit warning messages and * the user will have to use configuration options to override * the max datagram value supplied by the far endpoint. */ switch (udptl->error_correction_scheme) { case UDPTL_ERROR_CORRECTION_NONE: /* need room for sequence number, length indicator, redundancy * indicator and following length indicator */ new_max = udptl->far_max_datagram - 5; break; case UDPTL_ERROR_CORRECTION_REDUNDANCY: /* for this case, we'd like to send as many error correction entries * as possible (up to the number we're configured for), but we'll settle * for sending fewer if the configured number would cause the * calculated max IFP to be too small for effective operation * * need room for sequence number, length indicators and the * configured number of redundant packets * * note: we purposely don't allow error_correction_entries to drop to * zero in this loop; we'd rather send smaller IFPs (and thus reduce * the image data transfer rate) than sacrifice redundancy completely */ for (;;) { new_max = (udptl->far_max_datagram - 8) / (udptl->error_correction_entries + 1); if ((new_max < 80) && (udptl->error_correction_entries > 1)) { /* the max ifp is not large enough, subtract an * error correction entry and calculate again * */ --udptl->error_correction_entries; } else { break; } } break; case UDPTL_ERROR_CORRECTION_FEC: /* need room for sequence number, length indicators and a * a single IFP of the maximum size expected */ new_max = (udptl->far_max_datagram - 10) / 2; break; } /* subtract 5% of space for insurance */ udptl->far_max_ifp = new_max * 0.95; } enum ast_t38_ec_modes ast_udptl_get_error_correction_scheme(const struct ast_udptl *udptl) { return udptl->error_correction_scheme; } void ast_udptl_set_error_correction_scheme(struct ast_udptl *udptl, enum ast_t38_ec_modes ec) { udptl->error_correction_scheme = ec; switch (ec) { case UDPTL_ERROR_CORRECTION_FEC: udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_FEC; if (udptl->error_correction_entries == 0) { udptl->error_correction_entries = 3; } if (udptl->error_correction_span == 0) { udptl->error_correction_span = 3; } break; case UDPTL_ERROR_CORRECTION_REDUNDANCY: udptl->error_correction_scheme = UDPTL_ERROR_CORRECTION_REDUNDANCY; if (udptl->error_correction_entries == 0) { udptl->error_correction_entries = 3; } break; default: /* nothing to do */ break; }; /* reset calculated values so they'll be computed again */ udptl->local_max_datagram = -1; udptl->far_max_ifp = -1; } void ast_udptl_set_local_max_ifp(struct ast_udptl *udptl, unsigned int max_ifp) { /* make sure max_ifp is a positive value since a cast will take place when * when setting local_max_ifp */ if ((signed int) max_ifp > 0) { udptl->local_max_ifp = max_ifp; /* reset calculated values so they'll be computed again */ udptl->local_max_datagram = -1; } } unsigned int ast_udptl_get_local_max_datagram(struct ast_udptl *udptl) { if (udptl->local_max_datagram == -1) { calculate_local_max_datagram(udptl); } /* this function expects a unsigned value in return. */ if (udptl->local_max_datagram < 0) { return 0; } return udptl->local_max_datagram; } void ast_udptl_set_far_max_datagram(struct ast_udptl *udptl, unsigned int max_datagram) { if (!max_datagram || (max_datagram > FAX_MAX_DATAGRAM_LIMIT)) { udptl->far_max_datagram = DEFAULT_FAX_MAX_DATAGRAM; } else { udptl->far_max_datagram = max_datagram; } /* reset calculated values so they'll be computed again */ udptl->far_max_ifp = -1; } unsigned int ast_udptl_get_far_max_datagram(const struct ast_udptl *udptl) { if (udptl->far_max_datagram < 0) { return 0; } return udptl->far_max_datagram; } unsigned int ast_udptl_get_far_max_ifp(struct ast_udptl *udptl) { if (udptl->far_max_ifp == -1) { calculate_far_max_ifp(udptl); } if (udptl->far_max_ifp < 0) { return 0; } return udptl->far_max_ifp; } struct ast_udptl *ast_udptl_new_with_bindaddr(struct ast_sched_context *sched, struct io_context *io, int callbackmode, struct ast_sockaddr *addr) { struct ast_udptl *udptl; int x; int startplace; int i; long int flags; if (!(udptl = ast_calloc(1, sizeof(*udptl)))) return NULL; udptl->error_correction_span = udptlfecspan; udptl->error_correction_entries = udptlfecentries; udptl->far_max_datagram = -1; udptl->far_max_ifp = -1; udptl->local_max_ifp = -1; udptl->local_max_datagram = -1; for (i = 0; i <= UDPTL_BUF_MASK; i++) { udptl->rx[i].buf_len = -1; udptl->tx[i].buf_len = -1; } if ((udptl->fd = socket(ast_sockaddr_is_ipv6(addr) ? AF_INET6 : AF_INET, SOCK_DGRAM, 0)) < 0) { ast_free(udptl); ast_log(LOG_WARNING, "Unable to allocate socket: %s\n", strerror(errno)); return NULL; } flags = fcntl(udptl->fd, F_GETFL); fcntl(udptl->fd, F_SETFL, flags | O_NONBLOCK); #ifdef SO_NO_CHECK if (nochecksums) setsockopt(udptl->fd, SOL_SOCKET, SO_NO_CHECK, &nochecksums, sizeof(nochecksums)); #endif /* Find us a place */ x = (udptlstart == udptlend) ? udptlstart : (ast_random() % (udptlend - udptlstart)) + udptlstart; if (use_even_ports && (x & 1)) { ++x; } startplace = x; for (;;) { ast_sockaddr_copy(&udptl->us, addr); ast_sockaddr_set_port(&udptl->us, x); if (ast_bind(udptl->fd, &udptl->us) == 0) { break; } if (errno != EADDRINUSE) { ast_log(LOG_WARNING, "Unexpected bind error: %s\n", strerror(errno)); close(udptl->fd); ast_free(udptl); return NULL; } if (use_even_ports) { x += 2; } else { ++x; } if (x > udptlend) x = udptlstart; if (x == startplace) { ast_log(LOG_WARNING, "No UDPTL ports remaining\n"); close(udptl->fd); ast_free(udptl); return NULL; } } if (io && sched && callbackmode) { /* Operate this one in a callback mode */ udptl->sched = sched; udptl->io = io; udptl->ioid = ast_io_add(udptl->io, udptl->fd, udptlread, AST_IO_IN, udptl); } return udptl; } void ast_udptl_set_tag(struct ast_udptl *udptl, const char *format, ...) { va_list ap; if (udptl->tag) { ast_free(udptl->tag); udptl->tag = NULL; } va_start(ap, format); if (ast_vasprintf(&udptl->tag, format, ap) == -1) { udptl->tag = NULL; } va_end(ap); } int ast_udptl_setqos(struct ast_udptl *udptl, unsigned int tos, unsigned int cos) { return ast_netsock_set_qos(udptl->fd, tos, cos, "UDPTL"); } void ast_udptl_set_peer(struct ast_udptl *udptl, const struct ast_sockaddr *them) { ast_sockaddr_copy(&udptl->them, them); } void ast_udptl_get_peer(const struct ast_udptl *udptl, struct ast_sockaddr *them) { ast_sockaddr_copy(them, &udptl->them); } void ast_udptl_get_us(const struct ast_udptl *udptl, struct ast_sockaddr *us) { ast_sockaddr_copy(us, &udptl->us); } void ast_udptl_stop(struct ast_udptl *udptl) { ast_sockaddr_setnull(&udptl->them); } void ast_udptl_destroy(struct ast_udptl *udptl) { if (udptl->ioid) ast_io_remove(udptl->io, udptl->ioid); if (udptl->fd > -1) close(udptl->fd); if (udptl->tag) ast_free(udptl->tag); ast_free(udptl); } int ast_udptl_write(struct ast_udptl *s, struct ast_frame *f) { unsigned int seq; unsigned int len = f->datalen; int res; /* if no max datagram size is provided, use default value */ const int bufsize = (s->far_max_datagram > 0) ? s->far_max_datagram : DEFAULT_FAX_MAX_DATAGRAM; uint8_t buf[bufsize]; memset(buf, 0, sizeof(buf)); /* If we have no peer, return immediately */ if (ast_sockaddr_isnull(&s->them)) { return 0; } /* If there is no data length, return immediately */ if (f->datalen == 0) return 0; if ((f->frametype != AST_FRAME_MODEM) || (f->subclass.integer != AST_MODEM_T38)) { ast_log(LOG_WARNING, "(%s): UDPTL can only send T.38 data.\n", LOG_TAG(s)); return -1; } if (len > s->far_max_ifp) { ast_log(LOG_WARNING, "(%s): UDPTL asked to send %d bytes of IFP when far end only prepared to accept %d bytes; data loss will occur." "You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.\n", LOG_TAG(s), len, s->far_max_ifp); len = s->far_max_ifp; } /* Save seq_no for debug output because udptl_build_packet increments it */ seq = s->tx_seq_no & 0xFFFF; /* Cook up the UDPTL packet, with the relevant EC info. */ len = udptl_build_packet(s, buf, sizeof(buf), f->data.ptr, len); if ((signed int) len > 0 && !ast_sockaddr_isnull(&s->them)) { if ((res = ast_sendto(s->fd, buf, len, 0, &s->them)) < 0) ast_log(LOG_NOTICE, "(%s): UDPTL Transmission error to %s: %s\n", LOG_TAG(s), ast_sockaddr_stringify(&s->them), strerror(errno)); if (udptl_debug_test_addr(&s->them)) ast_verb(1, "UDPTL (%s): packet to %s (type %d, seq %d, len %d)\n", LOG_TAG(s), ast_sockaddr_stringify(&s->them), 0, seq, len); } return 0; } void ast_udptl_proto_unregister(struct ast_udptl_protocol *proto) { AST_RWLIST_WRLOCK(&protos); AST_RWLIST_REMOVE(&protos, proto, list); AST_RWLIST_UNLOCK(&protos); } int ast_udptl_proto_register(struct ast_udptl_protocol *proto) { struct ast_udptl_protocol *cur; AST_RWLIST_WRLOCK(&protos); AST_RWLIST_TRAVERSE(&protos, cur, list) { if (cur->type == proto->type) { ast_log(LOG_WARNING, "Tried to register same protocol '%s' twice\n", cur->type); AST_RWLIST_UNLOCK(&protos); return -1; } } AST_RWLIST_INSERT_TAIL(&protos, proto, list); AST_RWLIST_UNLOCK(&protos); return 0; } static struct ast_udptl_protocol *get_proto(struct ast_channel *chan) { struct ast_udptl_protocol *cur = NULL; AST_RWLIST_RDLOCK(&protos); AST_RWLIST_TRAVERSE(&protos, cur, list) { if (cur->type == chan->tech->type) break; } AST_RWLIST_UNLOCK(&protos); return cur; } int ast_udptl_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc) { struct ast_frame *f; struct ast_channel *who; struct ast_channel *cs[3]; struct ast_udptl *p0; struct ast_udptl *p1; struct ast_udptl_protocol *pr0; struct ast_udptl_protocol *pr1; struct ast_sockaddr ac0; struct ast_sockaddr ac1; struct ast_sockaddr t0; struct ast_sockaddr t1; void *pvt0; void *pvt1; int to; ast_channel_lock(c0); while (ast_channel_trylock(c1)) { ast_channel_unlock(c0); usleep(1); ast_channel_lock(c0); } pr0 = get_proto(c0); pr1 = get_proto(c1); if (!pr0) { ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c0->name); ast_channel_unlock(c0); ast_channel_unlock(c1); return -1; } if (!pr1) { ast_log(LOG_WARNING, "Can't find native functions for channel '%s'\n", c1->name); ast_channel_unlock(c0); ast_channel_unlock(c1); return -1; } pvt0 = c0->tech_pvt; pvt1 = c1->tech_pvt; p0 = pr0->get_udptl_info(c0); p1 = pr1->get_udptl_info(c1); if (!p0 || !p1) { /* Somebody doesn't want to play... */ ast_channel_unlock(c0); ast_channel_unlock(c1); return -2; } if (pr0->set_udptl_peer(c0, p1)) { ast_log(LOG_WARNING, "Channel '%s' failed to talk to '%s'\n", c0->name, c1->name); memset(&ac1, 0, sizeof(ac1)); } else { /* Store UDPTL peer */ ast_udptl_get_peer(p1, &ac1); } if (pr1->set_udptl_peer(c1, p0)) { ast_log(LOG_WARNING, "Channel '%s' failed to talk back to '%s'\n", c1->name, c0->name); memset(&ac0, 0, sizeof(ac0)); } else { /* Store UDPTL peer */ ast_udptl_get_peer(p0, &ac0); } ast_channel_unlock(c0); ast_channel_unlock(c1); cs[0] = c0; cs[1] = c1; cs[2] = NULL; for (;;) { if ((c0->tech_pvt != pvt0) || (c1->tech_pvt != pvt1) || (c0->masq || c0->masqr || c1->masq || c1->masqr)) { ast_debug(1, "Oooh, something is weird, backing out\n"); /* Tell it to try again later */ return -3; } to = -1; ast_udptl_get_peer(p1, &t1); ast_udptl_get_peer(p0, &t0); if (ast_sockaddr_cmp(&t1, &ac1)) { ast_debug(1, "Oooh, '%s' changed end address to %s\n", c1->name, ast_sockaddr_stringify(&t1)); ast_debug(1, "Oooh, '%s' was %s\n", c1->name, ast_sockaddr_stringify(&ac1)); ast_sockaddr_copy(&ac1, &t1); } if (ast_sockaddr_cmp(&t0, &ac0)) { ast_debug(1, "Oooh, '%s' changed end address to %s\n", c0->name, ast_sockaddr_stringify(&t0)); ast_debug(1, "Oooh, '%s' was %s\n", c0->name, ast_sockaddr_stringify(&ac0)); ast_sockaddr_copy(&ac0, &t0); } who = ast_waitfor_n(cs, 2, &to); if (!who) { ast_debug(1, "Ooh, empty read...\n"); /* check for hangup / whentohangup */ if (ast_check_hangup(c0) || ast_check_hangup(c1)) break; continue; } f = ast_read(who); if (!f) { *fo = f; *rc = who; ast_debug(1, "Oooh, got a %s\n", f ? "digit" : "hangup"); /* That's all we needed */ return 0; } else { if (f->frametype == AST_FRAME_MODEM) { /* Forward T.38 frames if they happen upon us */ if (who == c0) { ast_write(c1, f); } else if (who == c1) { ast_write(c0, f); } } ast_frfree(f); } /* Swap priority. Not that it's a big deal at this point */ cs[2] = cs[0]; cs[0] = cs[1]; cs[1] = cs[2]; } return -1; } static char *handle_cli_udptl_set_debug(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a) { switch (cmd) { case CLI_INIT: e->command = "udptl set debug {on|off|ip}"; e->usage = "Usage: udptl set debug {on|off|ip host[:port]}\n" " Enable or disable dumping of UDPTL packets.\n" " If ip is specified, limit the dumped packets to those to and from\n" " the specified 'host' with optional port.\n"; return NULL; case CLI_GENERATE: return NULL; } if (a->argc < 4 || a->argc > 5) return CLI_SHOWUSAGE; if (a->argc == 4) { if (!strncasecmp(a->argv[3], "on", 2)) { udptldebug = 1; memset(&udptldebugaddr, 0, sizeof(udptldebugaddr)); ast_cli(a->fd, "UDPTL Debugging Enabled\n"); } else if (!strncasecmp(a->argv[3], "off", 3)) { udptldebug = 0; ast_cli(a->fd, "UDPTL Debugging Disabled\n"); } else { return CLI_SHOWUSAGE; } } else { struct ast_sockaddr *addrs; if (strncasecmp(a->argv[3], "ip", 2)) return CLI_SHOWUSAGE; if (!ast_sockaddr_resolve(&addrs, a->argv[4], 0, 0)) { return CLI_SHOWUSAGE; } ast_sockaddr_copy(&udptldebugaddr, &addrs[0]); ast_cli(a->fd, "UDPTL Debugging Enabled for IP: %s\n", ast_sockaddr_stringify(&udptldebugaddr)); udptldebug = 1; ast_free(addrs); } return CLI_SUCCESS; } static struct ast_cli_entry cli_udptl[] = { AST_CLI_DEFINE(handle_cli_udptl_set_debug, "Enable/Disable UDPTL debugging") }; static void __ast_udptl_reload(int reload) { struct ast_config *cfg; const char *s; struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 }; cfg = ast_config_load2("udptl.conf", "udptl", config_flags); if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEUNCHANGED || cfg == CONFIG_STATUS_FILEINVALID) { return; } udptlstart = 4500; udptlend = 4999; udptlfecentries = 0; udptlfecspan = 0; use_even_ports = 0; if (cfg) { if ((s = ast_variable_retrieve(cfg, "general", "udptlstart"))) { udptlstart = atoi(s); if (udptlstart < 1024) { ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n"); udptlstart = 1024; } if (udptlstart > 65535) { ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n"); udptlstart = 65535; } } if ((s = ast_variable_retrieve(cfg, "general", "udptlend"))) { udptlend = atoi(s); if (udptlend < 1024) { ast_log(LOG_WARNING, "Ports under 1024 are not allowed for T.38.\n"); udptlend = 1024; } if (udptlend > 65535) { ast_log(LOG_WARNING, "Ports over 65535 are invalid.\n"); udptlend = 65535; } } if ((s = ast_variable_retrieve(cfg, "general", "udptlchecksums"))) { #ifdef SO_NO_CHECK if (ast_false(s)) nochecksums = 1; else nochecksums = 0; #else if (ast_false(s)) ast_log(LOG_WARNING, "Disabling UDPTL checksums is not supported on this operating system!\n"); #endif } if ((s = ast_variable_retrieve(cfg, "general", "T38FaxUdpEC"))) { ast_log(LOG_WARNING, "T38FaxUdpEC in udptl.conf is no longer supported; use the t38pt_udptl configuration option in sip.conf instead.\n"); } if ((s = ast_variable_retrieve(cfg, "general", "T38FaxMaxDatagram"))) { ast_log(LOG_WARNING, "T38FaxMaxDatagram in udptl.conf is no longer supported; value is now supplied by T.38 applications.\n"); } if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECEntries"))) { udptlfecentries = atoi(s); if (udptlfecentries < 1) { ast_log(LOG_WARNING, "Too small UDPTLFECEntries value. Defaulting to 1.\n"); udptlfecentries = 1; } if (udptlfecentries > MAX_FEC_ENTRIES) { ast_log(LOG_WARNING, "Too large UDPTLFECEntries value. Defaulting to %d.\n", MAX_FEC_ENTRIES); udptlfecentries = MAX_FEC_ENTRIES; } } if ((s = ast_variable_retrieve(cfg, "general", "UDPTLFECSpan"))) { udptlfecspan = atoi(s); if (udptlfecspan < 1) { ast_log(LOG_WARNING, "Too small UDPTLFECSpan value. Defaulting to 1.\n"); udptlfecspan = 1; } if (udptlfecspan > MAX_FEC_SPAN) { ast_log(LOG_WARNING, "Too large UDPTLFECSpan value. Defaulting to %d.\n", MAX_FEC_SPAN); udptlfecspan = MAX_FEC_SPAN; } } if ((s = ast_variable_retrieve(cfg, "general", "use_even_ports"))) { use_even_ports = ast_true(s); } ast_config_destroy(cfg); } if (udptlstart >= udptlend) { ast_log(LOG_WARNING, "Unreasonable values for UDPTL start/end ports; defaulting to 4500-4999.\n"); udptlstart = 4500; udptlend = 4999; } if (use_even_ports && (udptlstart & 1)) { ++udptlstart; ast_log(LOG_NOTICE, "Odd numbered udptlstart specified but use_even_ports enabled. udptlstart is now %d\n", udptlstart); } if (use_even_ports && (udptlend & 1)) { --udptlend; ast_log(LOG_NOTICE, "Odd numbered udptlend specified but use_event_ports enabled. udptlend is now %d\n", udptlend); } ast_verb(2, "UDPTL allocating from port range %d -> %d\n", udptlstart, udptlend); } int ast_udptl_reload(void) { __ast_udptl_reload(1); return 0; } void ast_udptl_init(void) { ast_cli_register_multiple(cli_udptl, ARRAY_LEN(cli_udptl)); __ast_udptl_reload(0); }