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rtp_proxy: Simplify AMR handling 

AMR frames on the MNCC interface are slightly different as they
include a single-byte payload_length indicator prior to the actual
payload.  Commit 3f201ac89952b68d05c0bb6cb41932b9cd898b19 introduced
more special-case handling than required, so I'm trying to simplify
things again.

We now also use msgb_put() more consistently, i.e. always put
before actually using the data, and use the return value of msgb_put()
rather than first making assumptions about the pointer, writing to it
and then calling msgb_put().
This commit is contained in:
Harald Welte 2014-05-17 13:43:01 +02:00
parent d8967f76a5
commit a87f8f9891
1 changed files with 26 additions and 30 deletions
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56
openbsc/src/libtrau/rtp_proxy.c
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@ -105,6 +105,9 @@ struct rtp_x_hdr {
#define RTP_VERSION 2 #define RTP_VERSION 2
/* 33 for FR, all other codecs have smaller size */
#define MAX_RTP_PAYLOAD_LEN 33
/* decode an rtp frame and create a new buffer with payload */ /* decode an rtp frame and create a new buffer with payload */
static int rtp_decode(struct msgb *msg, uint32_t callref, struct msgb **data) static int rtp_decode(struct msgb *msg, uint32_t callref, struct msgb **data)
{ {
@ -112,7 +115,7 @@ static int rtp_decode(struct msgb *msg, uint32_t callref, struct msgb **data)
struct gsm_data_frame *frame; struct gsm_data_frame *frame;
struct rtp_hdr *rtph = (struct rtp_hdr *)msg->data; struct rtp_hdr *rtph = (struct rtp_hdr *)msg->data;
struct rtp_x_hdr *rtpxh; struct rtp_x_hdr *rtpxh;
uint8_t *payload; uint8_t *payload, *payload_out;
int payload_len; int payload_len;
int msg_type; int msg_type;
int x_len; int x_len;
@ -200,33 +203,31 @@ static int rtp_decode(struct msgb *msg, uint32_t callref, struct msgb **data)
return -EINVAL; return -EINVAL;
} }
if (payload_len > 33) { if (payload_len > MAX_RTP_PAYLOAD_LEN) {
DEBUGPC(DLMUX, "RTP payload too large (%d octets)\n", DEBUGPC(DLMUX, "RTP payload too large (%d octets)\n",
payload_len); payload_len);
return -EINVAL; return -EINVAL;
} }
if (rtph->payload_type == RTP_PT_AMR) { /* always allocate for the maximum possible size to avoid
new_msg = msgb_alloc(sizeof(struct gsm_data_frame) + 1 * fragmentation */
+ payload_len, "GSM-DATA (AMR)"); new_msg = msgb_alloc(sizeof(struct gsm_data_frame) +
} else { MAX_RTP_PAYLOAD_LEN, "GSM-DATA (TCH)");
new_msg = msgb_alloc(sizeof(struct gsm_data_frame)
+ payload_len, "GSM-DATA");
}
if (!new_msg) if (!new_msg)
return -ENOMEM; return -ENOMEM;
frame = (struct gsm_data_frame *)(new_msg->data); frame = msgb_put(new_msg, sizeof(struct gsm_data_frame));
frame->msg_type = msg_type; frame->msg_type = msg_type;
frame->callref = callref; frame->callref = callref;
if (rtph->payload_type == RTP_PT_AMR) { if (rtph->payload_type == RTP_PT_AMR) {
frame->data[0] = payload_len; /* for FR/HR/EFR the length is implicit. In AMR, we
msgb_put(new_msg, sizeof(struct gsm_data_frame) + 1 * need to make it explicit by using the first byte of
+ payload_len); * the data[] buffer as length byte */
memcpy(frame->data + 1, payload, payload_len); uint8_t *data0 = msgb_put(new_msg, 1);
} else { *data0 = payload_len;
msgb_put(new_msg, sizeof(struct gsm_data_frame) + payload_len);
memcpy(frame->data, payload, payload_len);
} }
payload_out = msgb_put(new_msg, payload_len);
memcpy(payload_out, payload, payload_len);
*data = new_msg; *data = new_msg;
return 0; return 0;
@ -256,6 +257,7 @@ int rtp_send_frame(struct rtp_socket *rs, struct gsm_data_frame *frame)
struct rtp_sub_socket *rss = &rs->rtp; struct rtp_sub_socket *rss = &rs->rtp;
struct msgb *msg; struct msgb *msg;
struct rtp_hdr *rtph; struct rtp_hdr *rtph;
uint8_t *payload;
int payload_type; int payload_type;
int payload_len; int payload_len;
int duration; /* in samples */ int duration; /* in samples */
@ -316,21 +318,16 @@ int rtp_send_frame(struct rtp_socket *rs, struct gsm_data_frame *frame)
} }
} }
if (payload_len > 33) { if (payload_len > MAX_RTP_PAYLOAD_LEN) {
DEBUGPC(DLMUX, "RTP payload too large (%d octets)\n", DEBUGPC(DLMUX, "RTP payload too large (%d octets)\n",
payload_len); payload_len);
return -EINVAL; return -EINVAL;
} }
if (frame->msg_type == GSM_TCH_FRAME_AMR) msg = msgb_alloc(sizeof(struct rtp_hdr) + payload_len, "RTP-GSM");
msg = msgb_alloc(sizeof(struct rtp_hdr) + payload_len,
"RTP-GSM (AMR)");
else
msg = msgb_alloc(sizeof(struct rtp_hdr) + payload_len,
"RTP-GSM");
if (!msg) if (!msg)
return -ENOMEM; return -ENOMEM;
rtph = (struct rtp_hdr *)msg->data; rtph = (struct rtp_hdr *) msgb_put(msg, sizeof(struct rtp_hdr));
rtph->version = RTP_VERSION; rtph->version = RTP_VERSION;
rtph->padding = 0; rtph->padding = 0;
rtph->extension = 0; rtph->extension = 0;
@ -341,13 +338,12 @@ int rtp_send_frame(struct rtp_socket *rs, struct gsm_data_frame *frame)
rtph->timestamp = htonl(rs->transmit.timestamp); rtph->timestamp = htonl(rs->transmit.timestamp);
rs->transmit.timestamp += duration; rs->transmit.timestamp += duration;
rtph->ssrc = htonl(rs->transmit.ssrc); rtph->ssrc = htonl(rs->transmit.ssrc);
payload = msgb_put(msg, payload_len);
if (frame->msg_type == GSM_TCH_FRAME_AMR) if (frame->msg_type == GSM_TCH_FRAME_AMR)
memcpy(msg->data + sizeof(struct rtp_hdr), frame->data + 1, memcpy(payload, frame->data + 1, payload_len);
payload_len);
else else
memcpy(msg->data + sizeof(struct rtp_hdr), frame->data, memcpy(payload, frame->data, payload_len);
payload_len);
msgb_put(msg, sizeof(struct rtp_hdr) + payload_len);
msgb_enqueue(&rss->tx_queue, msg); msgb_enqueue(&rss->tx_queue, msg);
rss->bfd.when |= BSC_FD_WRITE; rss->bfd.when |= BSC_FD_WRITE;