Update HTTP/2 ALTSVC wireformat from draft-04 to draft-06.

net/spdy/spdy_alt_svc_wire_format.cc

+// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/spdy/spdy_alt_svc_wire_format.h"
+
+#include <limits>
+#include <string>
+
+#include "base/logging.h"
+#include "base/strings/stringprintf.h"
+
+namespace net {
+
+namespace {
+
+template <class T>
+bool ParsePositiveIntegerImpl(StringPiece::const_iterator c,
+                              StringPiece::const_iterator end,
+                              T* value) {
+  *value = 0;
+  for (; c != end && isdigit(*c); ++c) {
+    if (*value > std::numeric_limits<T>::max() / 10) {
+      return false;
+    }
+    *value *= 10;
+    if (*value > std::numeric_limits<T>::max() - (*c - '0')) {
+      return false;
+    }
+    *value += *c - '0';
+  }
+  return (c == end && *value > 0);
+}
+
+}  // namespace
+
+// static
+bool SpdyAltSvcWireFormat::ParseHeaderFieldValue(StringPiece value,
+                                                 std::string* protocol_id,
+                                                 std::string* host,
+                                                 uint16* port,
+                                                 uint32* max_age,
+                                                 double* p) {
+  *max_age = 86400;
+  *p = 1.0;
+
+  StringPiece::const_iterator c = value.begin();
+  StringPiece::const_iterator percent_encoded_protocol_id_end =
+      std::find(c, value.end(), '=');
+  if (percent_encoded_protocol_id_end == c ||
+      !PercentDecode(c, percent_encoded_protocol_id_end, protocol_id)) {
+    return false;
+  }
+  c = percent_encoded_protocol_id_end;
+  if (c == value.end()) {
+    return false;
+  }
+  DCHECK_EQ('=', *c);
+  ++c;
+  if (c == value.end() || *c != '"') {
+    return false;
+  }
+  ++c;
+  StringPiece::const_iterator alt_authority_begin = c;
+  for (; c != value.end() && *c != '"'; ++c) {
+    // Decode backslash encoding.
+    if (*c != '\\') {
+      continue;
+    }
+    ++c;
+    if (c == value.end()) {
+      return false;
+    }
+  }
+  if (c == alt_authority_begin || c == value.end()) {
+    return false;
+  }
+  DCHECK_EQ('"', *c);
+  if (!ParseAltAuthority(alt_authority_begin, c, host, port)) {
+    return false;
+  }
+  ++c;
+  StringPiece::const_iterator parameters_end = std::find(c, value.end(), ',');
+  while (c != parameters_end) {
+    SkipWhiteSpace(&c, parameters_end);
+    if (c == parameters_end) {
+      return true;
+    }
+    if (*c != ';') {
+      return false;
+    }
+    ++c;
+    SkipWhiteSpace(&c, parameters_end);
+    if (c == parameters_end) {
+      return true;
+    }
+    std::string parameter_name;
+    for (; c != parameters_end && *c != '=' && *c != ' ' && *c != '\t'; ++c) {
+      parameter_name.push_back(tolower(*c));
+    }
+    SkipWhiteSpace(&c, parameters_end);
+    if (c == parameters_end || *c != '=') {
+      return false;
+    }
+    ++c;
+    SkipWhiteSpace(&c, parameters_end);
+    StringPiece::const_iterator parameter_value_begin = c;
+    for (; c != parameters_end && *c != ';' && *c != ' ' && *c != '\t'; ++c) {
+    }
+    if (c == parameter_value_begin) {
+      return false;
+    }
+    if (parameter_name.compare("ma") == 0) {
+      if (!ParsePositiveInteger32(parameter_value_begin, c, max_age)) {
+        return false;
+      }
+    } else if (parameter_name.compare("p") == 0) {
+      if (!ParseProbability(parameter_value_begin, c, p)) {
+        return false;
+      }
+    }
+    SkipWhiteSpace(&c, parameters_end);
+  }
+  // TODO(bnc): Parse additional alternative services delimited by ','.
+  return true;
+}
+
+// static
+std::string SpdyAltSvcWireFormat::SerializeHeaderFieldValue(
+    const std::string& protocol_id,
+    const std::string& host,
+    uint16 port,
+    uint32 max_age,
+    double p) {
+  const char kNibbleToHex[] = "0123456789ABCDEF";
+  std::string value;
+  // Percent escape protocol id according to
+  // http://tools.ietf.org/html/rfc7230#section-3.2.6.
+  for (char c : protocol_id) {
+    if (isalnum(c)) {
+      value.push_back(c);
+      continue;
+    }
+    switch (c) {
+      case '!':
+      case '#':
+      case '$':
+      case '&':
+      case '\'':
+      case '*':
+      case '+':
+      case '-':
+      case '.':
+      case '^':
+      case '_':
+      case '`':
+      case '|':
+      case '~':
+        value.push_back(c);
+        break;
+      default:
+        value.push_back('%');
+        // Network byte order is big-endian.
+        value.push_back(kNibbleToHex[c >> 4]);
+        value.push_back(kNibbleToHex[c & 0x0f]);
+        break;
+    }
+  }
+  value.push_back('=');
+  value.push_back('"');
+  for (char c : host) {
+    if (c == '"' || c == '\\') {
+      value.push_back('\\');
+    }
+    value.push_back(c);
+  }
+  base::StringAppendF(&value, ":%d\"", port);
+  if (max_age != 86400) {
+    base::StringAppendF(&value, "; ma=%d", max_age);
+  }
+  if (p != 1.0) {
+    base::StringAppendF(&value, "; p=%.2f", p);
+  }
+  return value;
+}
+
+// static
+void SpdyAltSvcWireFormat::SkipWhiteSpace(StringPiece::const_iterator* c,
+                                          StringPiece::const_iterator end) {
+  for (; *c != end && (**c == ' ' || **c == '\t'); ++*c) {
+  }
+}
+
+// static
+bool SpdyAltSvcWireFormat::PercentDecode(StringPiece::const_iterator c,
+                                         StringPiece::const_iterator end,
+                                         std::string* output) {
+  output->clear();
+  for (; c != end; ++c) {
+    if (*c != '%') {
+      output->push_back(*c);
+      continue;
+    }
+    DCHECK_EQ('%', *c);
+    ++c;
+    if (c == end || !isxdigit(*c)) {
+      return false;
+    }
+    char decoded = tolower(*c);
+    // '0' is 0, 'a' is 10.
+    decoded += isdigit(*c) ? (0 - '0') : (10 - 'a');
+    // Network byte order is big-endian.
+    decoded <<= 4;
+    ++c;
+    if (c == end || !isxdigit(*c)) {
+      return false;
+    }
+    decoded += tolower(*c);
+    // '0' is 0, 'a' is 10.
+    decoded += isdigit(*c) ? (0 - '0') : (10 - 'a');
+    output->push_back(decoded);
+  }
+  return true;
+}
+
+// static
+bool SpdyAltSvcWireFormat::ParseAltAuthority(StringPiece::const_iterator c,
+                                             StringPiece::const_iterator end,
+                                             std::string* host,
+                                             uint16* port) {
+  host->clear();
+  for (; c != end && *c != ':'; ++c) {
+    if (*c == '"') {
+      // Port is mandatory.
+      return false;
+    }
+    if (*c == '\\') {
+      ++c;
+      if (c == end) {
+        return false;
+      }
+    }
+    host->push_back(*c);
+  }
+  if (c == end) {
+    return false;
+  }
+  DCHECK_EQ(':', *c);
+  ++c;
+  return ParsePositiveInteger16(c, end, port);
+}
+
+// static
+bool SpdyAltSvcWireFormat::ParsePositiveInteger16(
+    StringPiece::const_iterator c,
+    StringPiece::const_iterator end,
+    uint16* value) {
+  return ParsePositiveIntegerImpl<uint16>(c, end, value);
+}
+
+// static
+bool SpdyAltSvcWireFormat::ParsePositiveInteger32(
+    StringPiece::const_iterator c,
+    StringPiece::const_iterator end,
+    uint32* value) {
+  return ParsePositiveIntegerImpl<uint32>(c, end, value);
+}
+
+// Probability is a decimal fraction between 0.0 and 1.0, inclusive, with
+// optional leading zero, optional decimal point, and optional digits following
+// the decimal point, with the restriction that there has to be at least one
+// digit (that is, "" and "." are not valid).
+// static
+bool SpdyAltSvcWireFormat::ParseProbability(StringPiece::const_iterator c,
+                                            StringPiece::const_iterator end,
+                                            double* p) {
+  // "" is invalid.
+  if (c == end) {
+    return false;
+  }
+  // "." is invalid.
+  if (end - c == 1 && *c == '.') {
+    return false;
+  }
+  if (*c == '1') {
+    *p = 1.0;
+    ++c;
+  } else {
+    *p = 0.0;
+    if (*c == '0') {
+      ++c;
+    }
+  }
+  if (c == end) {
+    return true;
+  }
+  if (*c != '.') {
+    return false;
+  }
+  // So far we could have had ".", "0.", or "1.".
+  ++c;
+  double place_value = 0.1;
+  for (; c != end && isdigit(*c); ++c) {
+    *p += place_value * (*c - '0');
+    place_value *= 0.1;
+  }
+  return (c == end && *p <= 1.0);
+}
+
+}  // namespace net