FreeCalypso > hg > themwi-system-sw
view mgw/pstn2gsm.c @ 124:7e04d28fae8b
sip-in: default use-100rel to no
BulkVS servers act badly when we send a reliable 180 Ringing response
to an incoming call, even though they advertise 100rel support in
the Supported header in the INVITE packet, and we probably won't be
implementing 100rel for outbound because doing per-the-spec PRACK
as a UAC is just too burdensome. Therefore, we need to consider
100rel extension as not-really-supported in themwi-system-sw.
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sat, 01 Oct 2022 15:54:50 -0800 |
parents | d26d97974c8a |
children | f062c32a5116 |
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/* * In this module we implement our RTP gateway function * in the PSTN to GSM direction. */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <syslog.h> #include <unistd.h> #include <gsm.h> /* libgsm dependency */ #include "../include/tmgw_ctrl.h" #include "../include/tmgw_const.h" #include "struct.h" #include "select.h" #include "int_defs.h" extern uint16_t pcmu_decode_table[256]; extern uint16_t pcma_decode_table[256]; #define ERR_WRONG_UDP_SRC 0x0001 #define ERR_BAD_RTP_PACKET 0x0002 #define ERR_SSRC_CHANGE 0x0004 #define ERR_SEQ_BREAK 0x0008 #define ERR_TSTAMP_BREAK 0x0010 void pstn2gsm_rtp_in(in_fd, ep) struct endpoint *ep; { struct rtp_packet pkt; struct sockaddr_in sin_from; socklen_t addrlen; uint16_t *pcm_dec_table; int16_t seq_delta; int32_t ts_delta; int16_t pcm_samples[SAMPLES_PER_FRAME]; unsigned n; int rc, m_out; addrlen = sizeof(struct sockaddr_in); rc = recvfrom(in_fd, &pkt, sizeof pkt, 0, (struct sockaddr *) &sin_from, &addrlen); if (rc < 0) return; if (sin_from.sin_addr.s_addr != ep->rtp_pstn.remote_addr.sin_addr.s_addr || sin_from.sin_port != ep->rtp_pstn.remote_addr.sin_port) { if (!(ep->p2g_err_flags & ERR_WRONG_UDP_SRC)) { syslog(LOG_ERR, "PSTN RTP ep got UDP packet from wrong source"); ep->p2g_err_flags |= ERR_WRONG_UDP_SRC; } return; } if (rc != RTP_PACKET_SIZE_PSTN) { bad_rtp_pkt: if (!(ep->p2g_err_flags & ERR_BAD_RTP_PACKET)) { syslog(LOG_ERR, "Rx bad RTP packet on PSTN side"); ep->p2g_err_flags |= ERR_BAD_RTP_PACKET; } return; } if (pkt.v_p_x_cc != 0x80) goto bad_rtp_pkt; switch (pkt.m_pt & 0x7F) { case PSTN_CODEC_PCMU: pcm_dec_table = pcmu_decode_table; break; case PSTN_CODEC_PCMA: pcm_dec_table = pcma_decode_table; break; default: goto bad_rtp_pkt; } if (ep->p2g_state && pkt.ssrc != ep->p2g_ssrc) { if (!(ep->p2g_err_flags & ERR_SSRC_CHANGE)) { syslog(LOG_ERR, "PSTN RTP stream changed SSRC"); ep->p2g_err_flags |= ERR_SSRC_CHANGE; } ep->p2g_state = 0; } if (ep->p2g_state) { seq_delta = ntohs(pkt.seq) - ep->p2g_last_seq; ts_delta = ntohl(pkt.tstamp) - ep->p2g_last_ts; if (seq_delta <= 0) return; /* discard old or duplicate */ if (seq_delta != 1) { if (!(ep->p2g_err_flags & ERR_SEQ_BREAK)) { syslog(LOG_ERR, "PSTN RTP stream seq break"); ep->p2g_err_flags |= ERR_SEQ_BREAK; } m_out = 1; } else if (ts_delta != SAMPLES_PER_FRAME) { if (!(ep->p2g_err_flags & ERR_TSTAMP_BREAK)) { syslog(LOG_ERR, "PSTN RTP stream tstamp break"); ep->p2g_err_flags |= ERR_TSTAMP_BREAK; } m_out = 1; } else m_out = 0; } else m_out = 1; ep->p2g_state = 1; ep->p2g_ssrc = pkt.ssrc; ep->p2g_last_ts = ntohl(pkt.tstamp); ep->p2g_last_seq = ntohs(pkt.seq); /* actual transcoding and forwarding */ if (!(ep->fwd_mode & TMGW_FWD_ENABLE_PSTN2GSM)) { ep->p2g_drop_flag = 1; return; } if (ep->p2g_drop_flag) { ep->p2g_drop_flag = 0; m_out = 1; } for (n = 0; n < SAMPLES_PER_FRAME; n++) pcm_samples[n] = pcm_dec_table[pkt.payload[n]]; pkt.m_pt = ep->gsm_payload_type; if (m_out) pkt.m_pt |= 0x80; pkt.seq = htons(++ep->p2g_out_seq); switch (ep->gsm_payload_msg_type) { case GSM_TCHF_FRAME: gsm_encode(ep->gsm_encoder_state, pcm_samples, pkt.payload); break; } addrlen = sizeof(struct sockaddr_in); sendto(ep->rtp_gsm.rtp_fd, &pkt, ep->gsm_rtp_pkt_size, 0, (struct sockaddr *) &ep->rtp_gsm.remote_addr, addrlen); } pstn2gsm_init(ep) struct endpoint *ep; { if (ep->gsm_encoder_state) return TMGW_RESP_OK; switch (ep->gsm_payload_msg_type) { case GSM_TCHF_FRAME: ep->gsm_encoder_state = gsm_create(); if (!ep->gsm_encoder_state) return TMGW_RESP_ERR_RSRC; break; } select_handlers[ep->rtp_pstn.rtp_fd] = pstn2gsm_rtp_in; return TMGW_RESP_OK; }