diff options
Diffstat (limited to 'src/pq_rtp.c')
| -rw-r--r-- | src/pq_rtp.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/pq_rtp.c b/src/pq_rtp.c new file mode 100644 index 0000000..87e0f2e --- /dev/null +++ b/src/pq_rtp.c @@ -0,0 +1,226 @@ +/* Process Queue: RTP handling tasks */ + +/* (C) 2013 by Harald Welte <laforge@gnumonks.org> + * + * This file is part of gapk (GSM Audio Pocket Knife). + * + * gapk is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * gapk is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with gapk. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <errno.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> + +#include <arpa/inet.h> + +#include <gapk/codecs.h> +#include <gapk/formats.h> +#include <gapk/procqueue.h> + +#ifndef __BYTE_ORDER +# ifdef __APPLE__ +# define __BYTE_ORDER __DARWIN_BYTE_ORDER +# define __LITTLE_ENDIAN __DARWIN_LITTLE_ENDIAN +# define __BIG_ENDIAN __DARWIN_BIG_ENDIAN +# else +# error "__BYTE_ORDER should be defined by someone" +# endif +#endif + +/* according to RFC 3550 */ +struct rtp_hdr { +#if __BYTE_ORDER == __LITTLE_ENDIAN + uint8_t csrc_count:4, + extension:1, + padding:1, + version:2; + uint8_t payload_type:7, + marker:1; +#elif __BYTE_ORDER == __BIG_ENDIAN + uint8_t version:2, + padding:1, + extension:1, + csrc_count:4; + uint8_t marker:1, + payload_type:7; +#endif + uint16_t sequence; + uint32_t timestamp; + uint32_t ssrc; +} __attribute__((packed)); + +struct rtp_x_hdr { + uint16_t by_profile; + uint16_t length; +} __attribute__((packed)); + +#define RTP_VERSION 2 + +#define RTP_PT_GSM_FULL 3 + +struct pq_state_rtp { + int fd; + int blk_len; + + /* configurable */ + uint32_t duration; + uint8_t payload_type; + + /* auto-increment */ + uint16_t sequence; + uint32_t timestamp; + uint32_t ssrc; +}; + + +static int +pq_cb_rtp_input(void *_state, uint8_t *out, const uint8_t *in) +{ + struct pq_state_rtp *state = _state; + uint8_t buf[state->blk_len+256]; + struct rtp_hdr *rtph = (struct rtp_hdr *)buf; + struct rtp_x_hdr *rtpxh; + uint8_t *payload; + int rv, x_len, payload_len; + + rv = read(state->fd, buf, sizeof(buf)); + if (rv <= 0) + return -1; + + if (rv < sizeof(struct rtp_hdr)) + return -1; + + if (rtph->version != RTP_VERSION) + return -1; + + payload = buf + sizeof(struct rtp_hdr) + (rtph->csrc_count << 2); + payload_len = rv - sizeof(struct rtp_hdr) - (rtph->csrc_count << 2); + if (payload_len < 0) + return -1; + + if (rtph->extension) { + if (payload_len < sizeof(struct rtp_x_hdr)) + return -1; + rtpxh = (struct rtp_x_hdr *)payload; + x_len = ntohs(rtpxh->length) * 4 + sizeof(struct rtp_x_hdr); + payload += x_len; + payload_len -= x_len; + if (payload_len < 0) + return -1; + } + if (rtph->padding) { + if (payload_len < 0) + return -1; + payload_len -= payload[payload_len -1]; + if (payload_len < 0) + return -1; + } + + state->ssrc = ntohl(rtph->ssrc); + state->timestamp = ntohl(rtph->timestamp); + state->sequence = ntohs(rtph->sequence); + /* FIXME: check for discontinuity, ... */ + + memcpy(out, payload, payload_len); + + return 0; +} + +static int +pq_cb_rtp_output(void *_state, uint8_t *out, const uint8_t *in) +{ + struct pq_state_rtp *state = _state; + int len = state->blk_len + sizeof(struct rtp_hdr); + uint8_t buf[len]; + struct rtp_hdr *rtph = (struct rtp_hdr *)buf; + uint8_t *payload; + int rv; + + rtph->version = RTP_VERSION; + rtph->padding = 0; + rtph->extension = 0; + rtph->csrc_count = 0; + rtph->marker = 0; + rtph->payload_type = state->payload_type; + rtph->sequence = htons(state->sequence++); + rtph->timestamp = htonl(state->timestamp); + state->timestamp += state->duration; + rtph->ssrc = htonl(state->ssrc); + + payload = buf + sizeof(*rtph); + memcpy(payload, in, state->blk_len); + + rv = write(state->fd, buf, len); + return rv == len ? 0 : -1; +} + +static void +pq_cb_rtp_exit(void *_state) +{ + free(_state); +} + +static int +pq_queue_rtp_op(struct pq *pq, int udp_fd, unsigned int blk_len, int in_out_n) +{ + struct pq_item *item; + struct pq_state_rtp *state; + + state = calloc(1, sizeof(struct pq_state_rtp)); + if (!state) + return -ENOMEM; + + state->fd = udp_fd; + state->blk_len = blk_len; + + state->duration = 160; + + if (in_out_n == 0) { + state->ssrc = rand(); + state->sequence = random(); + state->timestamp = random(); + /* FIXME: other payload types!! */ + state->payload_type = RTP_PT_GSM_FULL; + } + + item = pq_add_item(pq); + if (!item) { + free(state); + return -ENOMEM; + } + + item->len_in = in_out_n ? 0 : blk_len; + item->len_out = in_out_n ? blk_len : 0; + item->state = state; + item->proc = in_out_n ? pq_cb_rtp_input : pq_cb_rtp_output; + item->exit = pq_cb_rtp_exit; + + return 0; +} + + +int +pq_queue_rtp_input(struct pq *pq, int udp_fd, unsigned int blk_len) +{ + return pq_queue_rtp_op(pq, udp_fd, blk_len, 1); +} + +int +pq_queue_rtp_output(struct pq *pq, int udp_fd, unsigned int blk_len) +{ + return pq_queue_rtp_op(pq, udp_fd, blk_len, 0); +} |