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gh-14 Improve RTCP builder checks
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@gavv
gavv committed Nov 27, 2023
1 parent a71303c commit 3c4e86c
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Showing 2 changed files with 58 additions and 44 deletions.
89 changes: 47 additions & 42 deletions src/internal_modules/roc_rtcp/builder.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ namespace roc {
namespace rtcp {

Builder::Builder(core::Slice<uint8_t>& data)
: state_(NONE)
: state_(TOP)
, data_(data)
, header_(NULL)
, xr_header_(NULL)
Expand All @@ -23,7 +23,7 @@ Builder::Builder(core::Slice<uint8_t>& data)
}

void Builder::begin_sr(const header::SenderReportPacket& sr) {
roc_panic_if_not(state_ == NONE);
roc_panic_if_msg(state_ != TOP, "rtcp builder: wrong call order");

cur_slice_ = data_.subslice(data_.size(), data_.size());
header::SenderReportPacket* p = (header::SenderReportPacket*)cur_slice_.extend(
Expand All @@ -36,21 +36,23 @@ void Builder::begin_sr(const header::SenderReportPacket& sr) {
}

void Builder::add_sr_report(const header::ReceptionReportBlock& report) {
roc_panic_if_not(state_ == SR_HEAD || state_ == SR_REPORT);
roc_panic_if_msg(state_ != SR_HEAD && state_ != SR_REPORT,
"rtcp builder: wrong call order");

add_report_(report);

state_ = SR_REPORT;
}

void Builder::end_sr() {
roc_panic_if_not(state_ == SR_HEAD || state_ == SR_REPORT);
roc_panic_if_msg(state_ != SR_HEAD && state_ != SR_REPORT,
"rtcp builder: wrong call order");

end_packet_();
}

void Builder::begin_rr(const header::ReceiverReportPacket& rr) {
roc_panic_if_not(state_ == NONE);
roc_panic_if_msg(state_ != TOP, "rtcp builder: wrong call order");

cur_slice_ = data_.subslice(data_.size(), data_.size());
header::ReceiverReportPacket* p = (header::ReceiverReportPacket*)cur_slice_.extend(
Expand All @@ -63,24 +65,25 @@ void Builder::begin_rr(const header::ReceiverReportPacket& rr) {
}

void Builder::add_rr_report(const header::ReceptionReportBlock& report) {
roc_panic_if_not(state_ == RR_HEAD || state_ == RR_REPORT);
roc_panic_if_msg(state_ != RR_HEAD && state_ != RR_REPORT,
"rtcp builder: wrong call order");

add_report_(report);

state_ = RR_REPORT;
}

void Builder::end_rr() {
roc_panic_if_not(state_ == RR_REPORT || state_ == RR_HEAD);
roc_panic_if_msg(state_ != RR_HEAD && state_ != RR_REPORT,
"rtcp builder: wrong call order");

end_packet_();
}

void Builder::begin_sdes() {
roc_panic_if_not(state_ == NONE);
roc_panic_if_msg(state_ != TOP, "rtcp builder: wrong call order");

roc_panic_if_msg(!report_written_,
"rtcp builder: sdes should come only after sr or rr");
roc_panic_if_msg(!report_written_, "rtcp builder: first packet should be SR or RR");

cur_slice_ = data_.subslice(data_.size(), data_.size());
header::SdesPacket* p =
Expand All @@ -92,7 +95,7 @@ void Builder::begin_sdes() {
}

void Builder::begin_sdes_chunk(const SdesChunk& chunk) {
roc_panic_if_not(state_ == SDES_HEAD);
roc_panic_if_msg(state_ != SDES_HEAD, "rtcp builder: wrong call order");

header::SdesChunkHeader* p =
(header::SdesChunkHeader*)cur_slice_.extend(sizeof(header::SdesChunkHeader));
Expand All @@ -105,9 +108,9 @@ void Builder::begin_sdes_chunk(const SdesChunk& chunk) {
}

void Builder::add_sdes_item(const SdesItem& item) {
roc_panic_if_not(state_ == SDES_CHUNK);
roc_panic_if_msg(state_ != SDES_CHUNK, "rtcp builder: wrong call order");

roc_panic_if_msg(!item.text, "rtcp builder: item text can't be null");
roc_panic_if_msg(!item.text, "rtcp builder: SDES item text can't be null");

const size_t text_size = strnlen(item.text, header::SdesItemHeader::MaxTextLen);
const size_t total_size = sizeof(header::SdesItemHeader) + text_size;
Expand All @@ -124,38 +127,35 @@ void Builder::add_sdes_item(const SdesItem& item) {
if (item.type == header::SDES_CNAME) {
roc_panic_if_msg(
cname_written_,
"rtcp builder: each sdes chunk should have one and only one cname item");

"rtcp builder: each SDES chunk should have exactly one CNAME item");
cname_written_ = true;
}
}

void Builder::end_sdes_chunk() {
roc_panic_if_not(state_ == SDES_CHUNK);
roc_panic_if_msg(state_ != SDES_CHUNK, "rtcp builder: wrong call order");

roc_panic_if_msg(
!cname_written_,
"rtcp builder: each sdes chunk should have one and only one cname item");
roc_panic_if_msg(!cname_written_,
"rtcp builder: each SDES chunk should have exactly one CNAME item");

// Adds at least one byte with zero value and aligns the end with 32 bit border.
size_t padding_size = header::padding_len(cur_slice_.size(), 1);
const size_t padding_size = header::padding_len(cur_slice_.size(), 1);
uint8_t* p = cur_slice_.extend(padding_size);
memset(p, 0, padding_size);

state_ = SDES_HEAD;
}

void Builder::end_sdes() {
roc_panic_if_not(state_ == SDES_HEAD);
roc_panic_if_msg(state_ != SDES_HEAD, "rtcp builder: wrong call order");

end_packet_();
}

void Builder::begin_bye() {
roc_panic_if_not(state_ == NONE);
roc_panic_if_msg(state_ != TOP, "rtcp builder: wrong call order");

roc_panic_if_msg(!report_written_,
"rtcp builder: bye should come only after sr or rr");
roc_panic_if_msg(!report_written_, "rtcp builder: first packet should be SR or RR");

cur_slice_ = data_.subslice(data_.size(), data_.size());
header::ByePacket* p =
Expand All @@ -167,7 +167,8 @@ void Builder::begin_bye() {
}

void Builder::add_bye_ssrc(const packet::stream_source_t ssrc) {
roc_panic_if_not(state_ == BYE_HEAD || state_ == BYE_SSRC);
roc_panic_if_msg(state_ != BYE_HEAD && state_ != BYE_SSRC,
"rtcp builder: wrong call order");

header::ByeSourceHeader* p =
(header::ByeSourceHeader*)cur_slice_.extend(sizeof(header::ByeSourceHeader));
Expand All @@ -179,9 +180,9 @@ void Builder::add_bye_ssrc(const packet::stream_source_t ssrc) {
}

void Builder::add_bye_reason(const char* reason) {
roc_panic_if_not(state_ == BYE_SSRC);
roc_panic_if_msg(state_ != BYE_SSRC, "rtcp builder: wrong call order");

roc_panic_if_msg(!reason, "rtcp builder: bye reason can't be null");
roc_panic_if_msg(!reason, "rtcp builder: BYE reason can't be null");

const size_t text_size = strnlen(reason, header::ByeReasonHeader::MaxTextLen);
const size_t total_size = sizeof(header::ByeReasonHeader) + text_size;
Expand All @@ -203,16 +204,16 @@ void Builder::add_bye_reason(const char* reason) {
}

void Builder::end_bye() {
roc_panic_if_not(state_ == BYE_SSRC || state_ == BYE_REASON);
roc_panic_if_msg(state_ != BYE_SSRC && state_ != BYE_REASON,
"rtcp builder: wrong call order");

end_packet_();
}

void Builder::begin_xr(const header::XrPacket& xr) {
roc_panic_if_not(state_ == NONE);
roc_panic_if_msg(state_ != TOP, "rtcp builder: wrong call order");

roc_panic_if_msg(!report_written_,
"rtcp builder: xr should come only after sr or rr");
roc_panic_if_msg(!report_written_, "rtcp builder: first packet should be SR or RR");

cur_slice_ = data_.subslice(data_.size(), data_.size());
header::XrPacket* p = (header::XrPacket*)cur_slice_.extend(sizeof(header::XrPacket));
Expand All @@ -223,7 +224,7 @@ void Builder::begin_xr(const header::XrPacket& xr) {
}

void Builder::add_xr_rrtr(const header::XrRrtrBlock& rrtr) {
roc_panic_if_not(state_ == XR_HEAD);
roc_panic_if_msg(state_ != XR_HEAD, "rtcp builder: wrong call order");

header::XrRrtrBlock* p =
(header::XrRrtrBlock*)cur_slice_.extend(sizeof(header::XrRrtrBlock));
Expand All @@ -233,7 +234,7 @@ void Builder::add_xr_rrtr(const header::XrRrtrBlock& rrtr) {
}

void Builder::begin_xr_dlrr(const header::XrDlrrBlock& dlrr) {
roc_panic_if_not(state_ == XR_HEAD);
roc_panic_if_msg(state_ != XR_HEAD, "rtcp builder: wrong call order");

header::XrDlrrBlock* p =
(header::XrDlrrBlock*)cur_slice_.extend(sizeof(header::XrDlrrBlock));
Expand All @@ -244,7 +245,8 @@ void Builder::begin_xr_dlrr(const header::XrDlrrBlock& dlrr) {
}

void Builder::add_xr_dlrr_report(const header::XrDlrrSubblock& report) {
roc_panic_if_not(state_ == XR_DLRR_HEAD || state_ == XR_DLRR_REPORT);
roc_panic_if_msg(state_ != XR_DLRR_HEAD && state_ != XR_DLRR_REPORT,
"rtcp builder: wrong call order");

header::XrDlrrSubblock* p =
(header::XrDlrrSubblock*)cur_slice_.extend(sizeof(header::XrDlrrSubblock));
Expand All @@ -254,15 +256,15 @@ void Builder::add_xr_dlrr_report(const header::XrDlrrSubblock& report) {
}

void Builder::end_xr_dlrr() {
roc_panic_if_not(state_ == XR_DLRR_REPORT);
roc_panic_if_msg(state_ != XR_DLRR_REPORT, "rtcp builder: wrong call order");

xr_header_->set_len_bytes(size_t(cur_slice_.data_end() - (uint8_t*)xr_header_));

state_ = XR_HEAD;
}

void Builder::end_xr() {
roc_panic_if_not(state_ == XR_HEAD);
roc_panic_if_msg(state_ != XR_HEAD, "rtcp builder: wrong call order");

end_packet_();
}
Expand All @@ -281,24 +283,27 @@ void Builder::end_packet_() {
data_.extend(cur_slice_.size());
cur_slice_ = core::Slice<uint8_t>();

state_ = NONE;
state_ = TOP;
}

void Builder::add_padding(size_t padding_len) {
roc_panic_if_not(state_ == NONE);
roc_panic_if_not(header_);
roc_panic_if_not(!header_->has_padding());
roc_panic_if_not(padding_len % 4 == 0 && padding_len >= 1 && padding_len <= 255);
roc_panic_if_msg(state_ != TOP || !header_, "rtcp builder: wrong call order");

roc_panic_if_msg(padding_len % 4 != 0 || padding_len < 1 || padding_len > 255,
"rtcp builder: bad packet padding:"
" should be multiple of 4 in range [1; 255], got %lu",
(unsigned long)padding_len);

header_->set_padding(true);
header_->set_len_bytes(header_->len_bytes() + padding_len);

uint8_t* p = data_.extend(padding_len);

if (padding_len > 1) {
memset(p, 0, padding_len - 1);
}
p[padding_len - 1] = (uint8_t)padding_len;

state_ = END;
}

} // namespace rtcp
Expand Down
13 changes: 11 additions & 2 deletions src/internal_modules/roc_rtcp/builder.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,13 @@ namespace roc {
namespace rtcp {

//! RTCP compound packet builder.
//!
//! Builder will panic if any of the following rules is violated
//! (mandated by RFC 3550):
//! - First packet should be SR or RR.
//! - At least one packet should be present.
//! - Each SDES chunk should have exactly one CNAME item.
//! - Padding can be added only to last packet.
class Builder : public core::NonCopyable<> {
public:
//! Initialize builder.
Expand Down Expand Up @@ -121,6 +128,7 @@ class Builder : public core::NonCopyable<> {
//! @{

//! Add given number of padding bytes to last packet.
//! Padding should be multiple of 4 in range [1; 255].
void add_padding(size_t padding_len);

//! @}
Expand All @@ -130,7 +138,7 @@ class Builder : public core::NonCopyable<> {
void end_packet_();

enum State {
NONE,
TOP,
SR_HEAD,
SR_REPORT,
RR_HEAD,
Expand All @@ -142,7 +150,8 @@ class Builder : public core::NonCopyable<> {
SDES_CHUNK,
BYE_HEAD,
BYE_SSRC,
BYE_REASON
BYE_REASON,
END
};

State state_;
Expand Down

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