Add readv and writev for more efficient API packets (#2342)

esphome/components/api/api_connection.cpp

@@ -702,15 +702,7 @@ bool APIConnection::send_log_message(int level, const char *tag, const char *lin
   // string message = 3;
   buffer.encode_string(3, line, strlen(line));
   // SubscribeLogsResponse - 29
-  bool success = this->send_buffer(buffer, 29);
-  if (!success) {
-    buffer = this->create_buffer();
-    // bool send_failed = 4;
-    buffer.encode_bool(4, true);
-    return this->send_buffer(buffer, 29);
-  } else {
-    return true;
-  }
+  return this->send_buffer(buffer, 29);
 }
 
 HelloResponse APIConnection::hello(const HelloRequest &msg) {
@@ -783,8 +775,23 @@ void APIConnection::subscribe_home_assistant_states(const SubscribeHomeAssistant
 bool APIConnection::send_buffer(ProtoWriteBuffer buffer, uint32_t message_type) {
   if (this->remove_)
     return false;
-  if (!this->helper_->can_write_without_blocking())
-    return false;
+  if (!this->helper_->can_write_without_blocking()) {
+    delay(0);
+    APIError err = helper_->loop();
+    if (err != APIError::OK) {
+      on_fatal_error();
+      ESP_LOGW(TAG, "%s: Socket operation failed: %s errno=%d", client_info_.c_str(), api_error_to_str(err), errno);
+      return false;
+    }
+    if (!this->helper_->can_write_without_blocking()) {
+      // SubscribeLogsResponse
+      if (message_type != 29) {
+        ESP_LOGV(TAG, "Cannot send message because of TCP buffer space");
+      }
+      delay(0);
+      return false;
+    }
+  }
 
   APIError err = this->helper_->write_packet(message_type, buffer.get_buffer()->data(), buffer.get_buffer()->size());
   if (err == APIError::WOULD_BLOCK)

esphome/components/api/api_frame_helper.cpp

@@ -125,13 +125,6 @@ APIError APINoiseFrameHelper::init() {
     HELPER_LOG("Setting nonblocking failed with errno %d", errno);
     return APIError::TCP_NONBLOCKING_FAILED;
   }
-  int enable = 1;
-  err = socket_->setsockopt(IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(int));
-  if (err != 0) {
-    state_ = State::FAILED;
-    HELPER_LOG("Setting nodelay failed with errno %d", errno);
-    return APIError::TCP_NODELAY_FAILED;
-  }
 
   // init prologue
   prologue_.insert(prologue_.end(), PROLOGUE_INIT, PROLOGUE_INIT + strlen(PROLOGUE_INIT));
@@ -494,12 +487,13 @@ APIError APINoiseFrameHelper::write_packet(uint16_t type, const uint8_t *payload
   size_t total_len = 3 + mbuf.size;
   tmpbuf[1] = (uint8_t)(mbuf.size >> 8);
   tmpbuf[2] = (uint8_t) mbuf.size;
+
+  struct iovec iov;
+  iov.iov_base = &tmpbuf[0];
+  iov.iov_len = total_len;
+
   // write raw to not have two packets sent if NAGLE disabled
-  aerr = write_raw_(&tmpbuf[0], total_len);
-  if (aerr != APIError::OK) {
-    return aerr;
-  }
-  return APIError::OK;
+  return write_raw_(&iov, 1);
 }
 APIError APINoiseFrameHelper::try_send_tx_buf_() {
   // try send from tx_buf
@@ -526,16 +520,19 @@ APIError APINoiseFrameHelper::try_send_tx_buf_() {
  * @param data The data to write
  * @param len The length of data
  */
-APIError APINoiseFrameHelper::write_raw_(const uint8_t *data, size_t len) {
-  if (len == 0)
+APIError APINoiseFrameHelper::write_raw_(const struct iovec *iov, int iovcnt) {
+  if (iovcnt == 0)
     return APIError::OK;
   int err;
   APIError aerr;
 
-  // uncomment for even more debugging
+  size_t total_write_len = 0;
+  for (int i = 0; i < iovcnt; i++) {
 #ifdef HELPER_LOG_PACKETS
-  ESP_LOGVV(TAG, "Sending raw: %s", hexencode(data, len).c_str());
+    ESP_LOGVV(TAG, "Sending raw: %s", hexencode(reinterpret_cast<uint8_t *>(iov[i].iov_base), iov[i].iov_len).c_str());
 #endif
+    total_write_len += iov[i].iov_len;
+  }
 
   if (!tx_buf_.empty()) {
     // try to empty tx_buf_ first
@@ -546,41 +543,56 @@ APIError APINoiseFrameHelper::write_raw_(const uint8_t *data, size_t len) {
 
   if (!tx_buf_.empty()) {
     // tx buf not empty, can't write now because then stream would be inconsistent
-    tx_buf_.insert(tx_buf_.end(), data, data + len);
+    for (int i = 0; i < iovcnt; i++) {
+      tx_buf_.insert(tx_buf_.end(), reinterpret_cast<uint8_t *>(iov[i].iov_base),
+                     reinterpret_cast<uint8_t *>(iov[i].iov_base) + iov[i].iov_len);
+    }
     return APIError::OK;
   }
 
-  ssize_t sent = socket_->write(data, len);
+  ssize_t sent = socket_->writev(iov, iovcnt);
   if (is_would_block(sent)) {
     // operation would block, add buffer to tx_buf
-    tx_buf_.insert(tx_buf_.end(), data, data + len);
+    for (int i = 0; i < iovcnt; i++) {
+      tx_buf_.insert(tx_buf_.end(), reinterpret_cast<uint8_t *>(iov[i].iov_base),
+                     reinterpret_cast<uint8_t *>(iov[i].iov_base) + iov[i].iov_len);
+    }
     return APIError::OK;
   } else if (sent == -1) {
     // an error occured
     state_ = State::FAILED;
     HELPER_LOG("Socket write failed with errno %d", errno);
     return APIError::SOCKET_WRITE_FAILED;
-  } else if (sent != len) {
+  } else if (sent != total_write_len) {
     // partially sent, add end to tx_buf
-    tx_buf_.insert(tx_buf_.end(), data + sent, data + len);
+    size_t to_consume = sent;
+    for (int i = 0; i < iovcnt; i++) {
+      if (to_consume >= iov[i].iov_len) {
+        to_consume -= iov[i].iov_len;
+      } else {
+        tx_buf_.insert(tx_buf_.end(), reinterpret_cast<uint8_t *>(iov[i].iov_base) + to_consume,
+                       reinterpret_cast<uint8_t *>(iov[i].iov_base) + iov[i].iov_len);
+        to_consume = 0;
+      }
+    }
     return APIError::OK;
   }
   // fully sent
   return APIError::OK;
 }
 APIError APINoiseFrameHelper::write_frame_(const uint8_t *data, size_t len) {
-  APIError aerr;
-
   uint8_t header[3];
   header[0] = 0x01;  // indicator
   header[1] = (uint8_t)(len >> 8);
   header[2] = (uint8_t) len;
 
-  aerr = write_raw_(header, 3);
-  if (aerr != APIError::OK)
-    return aerr;
-  aerr = write_raw_(data, len);
-  return aerr;
+  struct iovec iov[2];
+  iov[0].iov_base = header;
+  iov[0].iov_len = 3;
+  iov[1].iov_base = const_cast<uint8_t *>(data);
+  iov[1].iov_len = len;
+
+  return write_raw_(iov, 2);
 }
 
 /** Initiate the data structures for the handshake.
@@ -709,13 +721,6 @@ APIError APIPlaintextFrameHelper::init() {
     HELPER_LOG("Setting nonblocking failed with errno %d", errno);
     return APIError::TCP_NONBLOCKING_FAILED;
   }
-  int enable = 1;
-  err = socket_->setsockopt(IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(int));
-  if (err != 0) {
-    state_ = State::FAILED;
-    HELPER_LOG("Setting nodelay failed with errno %d", errno);
-    return APIError::TCP_NODELAY_FAILED;
-  }
 
   state_ = State::DATA;
   return APIError::OK;
@@ -863,15 +868,13 @@ APIError APIPlaintextFrameHelper::write_packet(uint16_t type, const uint8_t *pay
   ProtoVarInt(payload_len).encode(header);
   ProtoVarInt(type).encode(header);
 
-  aerr = write_raw_(&header[0], header.size());
-  if (aerr != APIError::OK) {
-    return aerr;
-  }
-  aerr = write_raw_(payload, payload_len);
-  if (aerr != APIError::OK) {
-    return aerr;
-  }
-  return APIError::OK;
+  struct iovec iov[2];
+  iov[0].iov_base = &header[0];
+  iov[0].iov_len = header.size();
+  iov[1].iov_base = const_cast<uint8_t *>(payload);
+  iov[1].iov_len = payload_len;
+
+  return write_raw_(iov, 2);
 }
 APIError APIPlaintextFrameHelper::try_send_tx_buf_() {
   // try send from tx_buf
@@ -896,16 +899,19 @@ APIError APIPlaintextFrameHelper::try_send_tx_buf_() {
  * @param data The data to write
  * @param len The length of data
  */
-APIError APIPlaintextFrameHelper::write_raw_(const uint8_t *data, size_t len) {
-  if (len == 0)
+APIError APIPlaintextFrameHelper::write_raw_(const struct iovec *iov, int iovcnt) {
+  if (iovcnt == 0)
     return APIError::OK;
   int err;
   APIError aerr;
 
-  // uncomment for even more debugging
+  size_t total_write_len = 0;
+  for (int i = 0; i < iovcnt; i++) {
 #ifdef HELPER_LOG_PACKETS
-  ESP_LOGVV(TAG, "Sending raw: %s", hexencode(data, len).c_str());
+    ESP_LOGVV(TAG, "Sending raw: %s", hexencode(reinterpret_cast<uint8_t *>(iov[i].iov_base), iov[i].iov_len).c_str());
 #endif
+    total_write_len += iov[i].iov_len;
+  }
 
   if (!tx_buf_.empty()) {
     // try to empty tx_buf_ first
@@ -916,23 +922,38 @@ APIError APIPlaintextFrameHelper::write_raw_(const uint8_t *data, size_t len) {
 
   if (!tx_buf_.empty()) {
     // tx buf not empty, can't write now because then stream would be inconsistent
-    tx_buf_.insert(tx_buf_.end(), data, data + len);
+    for (int i = 0; i < iovcnt; i++) {
+      tx_buf_.insert(tx_buf_.end(), reinterpret_cast<uint8_t *>(iov[i].iov_base),
+                     reinterpret_cast<uint8_t *>(iov[i].iov_base) + iov[i].iov_len);
+    }
     return APIError::OK;
   }
 
-  ssize_t sent = socket_->write(data, len);
+  ssize_t sent = socket_->writev(iov, iovcnt);
   if (is_would_block(sent)) {
     // operation would block, add buffer to tx_buf
-    tx_buf_.insert(tx_buf_.end(), data, data + len);
+    for (int i = 0; i < iovcnt; i++) {
+      tx_buf_.insert(tx_buf_.end(), reinterpret_cast<uint8_t *>(iov[i].iov_base),
+                     reinterpret_cast<uint8_t *>(iov[i].iov_base) + iov[i].iov_len);
+    }
     return APIError::OK;
   } else if (sent == -1) {
     // an error occured
     state_ = State::FAILED;
     HELPER_LOG("Socket write failed with errno %d", errno);
     return APIError::SOCKET_WRITE_FAILED;
-  } else if (sent != len) {
+  } else if (sent != total_write_len) {
     // partially sent, add end to tx_buf
-    tx_buf_.insert(tx_buf_.end(), data + sent, data + len);
+    size_t to_consume = sent;
+    for (int i = 0; i < iovcnt; i++) {
+      if (to_consume >= iov[i].iov_len) {
+        to_consume -= iov[i].iov_len;
+      } else {
+        tx_buf_.insert(tx_buf_.end(), reinterpret_cast<uint8_t *>(iov[i].iov_base) + to_consume,
+                       reinterpret_cast<uint8_t *>(iov[i].iov_base) + iov[i].iov_len);
+        to_consume = 0;
+      }
+    }
     return APIError::OK;
   }
   // fully sent

esphome/components/api/api_frame_helper.h

@@ -58,6 +58,7 @@ const char *api_error_to_str(APIError err);
 
 class APIFrameHelper {
  public:
+  virtual ~APIFrameHelper() = default;
   virtual APIError init() = 0;
   virtual APIError loop() = 0;
   virtual APIError read_packet(ReadPacketBuffer *buffer) = 0;
@@ -96,7 +97,7 @@ class APINoiseFrameHelper : public APIFrameHelper {
   APIError try_read_frame_(ParsedFrame *frame);
   APIError try_send_tx_buf_();
   APIError write_frame_(const uint8_t *data, size_t len);
-  APIError write_raw_(const uint8_t *data, size_t len);
+  APIError write_raw_(const struct iovec *iov, int iovcnt);
   APIError init_handshake_();
   APIError check_handshake_finished_();
   void send_explicit_handshake_reject_(const std::string &reason);
@@ -154,7 +155,7 @@ class APIPlaintextFrameHelper : public APIFrameHelper {
 
   APIError try_read_frame_(ParsedFrame *frame);
   APIError try_send_tx_buf_();
-  APIError write_raw_(const uint8_t *data, size_t len);
+  APIError write_raw_(const struct iovec *iov, int iovcnt);
 
   std::unique_ptr<socket::Socket> socket_;