dns_util.cc revision 5821806d5e7f356e8fa4b058a389a808ea183019
15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2011 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "net/base/dns_util.h" 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <cstring> 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace net { 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Based on DJB's public domain code. 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool DNSDomainFromDot(const base::StringPiece& dotted, std::string* out) { 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const char* buf = dotted.data(); 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned n = dotted.size(); 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) char label[63]; 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned int labellen = 0; /* <= sizeof label */ 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) char name[255]; 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned int namelen = 0; /* <= sizeof name */ 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) char ch; 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (;;) { 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!n) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ch = *buf++; 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) --n; 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (ch == '.') { 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (labellen) { 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (namelen + labellen + 1 > sizeof name) 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) name[namelen++] = labellen; 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) memcpy(name + namelen, label, labellen); 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) namelen += labellen; 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) labellen = 0; 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) continue; 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (labellen >= sizeof label) 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) label[labellen++] = ch; 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (labellen) { 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (namelen + labellen + 1 > sizeof name) 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) name[namelen++] = labellen; 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) memcpy(name + namelen, label, labellen); 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) namelen += labellen; 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) labellen = 0; 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (namelen + 1 > sizeof name) 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) name[namelen++] = 0; // This is the root label (of length 0). 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *out = std::string(name, namelen); 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)std::string DNSDomainToString(const base::StringPiece& domain) { 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) std::string ret; 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (unsigned i = 0; i < domain.size() && domain[i]; i += domain[i] + 1) { 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#if CHAR_MIN < 0 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (domain[i] < 0) 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ""; 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (domain[i] > 63) 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ""; 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (i) 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ret += "."; 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (static_cast<unsigned>(domain[i]) + i + 1 > domain.size()) 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ""; 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) domain.substr(i + 1, domain[i]).AppendToString(&ret); 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ret; 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool IsSTD3ASCIIValidCharacter(char c) { 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (c <= 0x2c) 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (c >= 0x7b) 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (c >= 0x2e && c <= 0x2f) 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (c >= 0x3a && c <= 0x40) 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (c >= 0x5b && c <= 0x60) 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)std::string TrimEndingDot(const base::StringPiece& host) { 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::StringPiece host_trimmed = host; 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) size_t len = host_trimmed.length(); 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len > 1 && host_trimmed[len - 1] == '.') { 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) host_trimmed.remove_suffix(1); 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return host_trimmed.as_string(); 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool DnsResponseBuffer::U8(uint8* v) { 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len_ < 1) 1065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *v = *p_; 1085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p_++; 1095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len_--; 1105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 1115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool DnsResponseBuffer::U16(uint16* v) { 1145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len_ < 2) 1155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *v = static_cast<uint16>(p_[0]) << 8 | 1175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<uint16>(p_[1]); 1185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p_ += 2; 1195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len_ -= 2; 1205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 1215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool DnsResponseBuffer::U32(uint32* v) { 1245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len_ < 4) 1255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *v = static_cast<uint32>(p_[0]) << 24 | 1275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<uint32>(p_[1]) << 16 | 1285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<uint32>(p_[2]) << 8 | 1295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<uint32>(p_[3]); 1305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p_ += 4; 1315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len_ -= 4; 1325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 1335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool DnsResponseBuffer::Skip(unsigned n) { 1365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len_ < n) 1375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p_ += n; 1395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len_ -= n; 1405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 1415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool DnsResponseBuffer::Block(base::StringPiece* out, unsigned len) { 1445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len_ < len) 1455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *out = base::StringPiece(reinterpret_cast<const char*>(p_), len); 1475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p_ += len; 1485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len_ -= len; 1495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 1505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// DNSName parses a (possibly compressed) DNS name from the packet. If |name| 1535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// is not NULL, then the name is written into it. See RFC 1035 section 4.1.4. 1545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool DnsResponseBuffer::DNSName(std::string* name) { 1555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned jumps = 0; 1565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const uint8* p = p_; 1575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned len = len_; 1585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (name) 1605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) name->clear(); 1615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (;;) { 1635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len < 1) 1645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) uint8 d = *p; 1665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p++; 1675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len--; 1685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The two couple of bits of the length give the type of the length. It's 1705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // either a direct length or a pointer to the remainder of the name. 1715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if ((d & 0xc0) == 0xc0) { 1725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // This limit matches the depth limit in djbdns. 1735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (jumps > 100) 1745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len < 1) 1765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) uint16 offset = static_cast<uint16>(d) << 8 | 1785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static_cast<uint16>(p[0]); 1795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) offset &= 0x3ff; 1805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p++; 1815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len--; 1825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (jumps == 0) { 1845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p_ = p; 1855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len_ = len; 1865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) jumps++; 1885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (offset >= packet_len_) 1905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p = &packet_[offset]; 1925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len = packet_len_ - offset; 1935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else if ((d & 0xc0) == 0) { 1945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) uint8 label_len = d; 1955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (len < label_len) 1965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (name && label_len) { 1985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!name->empty()) 1995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) name->append("."); 2005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) name->append(reinterpret_cast<const char*>(p), label_len); 2015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p += label_len; 2035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len -= label_len; 2045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (jumps == 0) { 2065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) p_ = p; 2075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) len_ = len; 2085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (label_len == 0) 2115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 2125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else { 2135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 2145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 2165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 2185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 2195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 2205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace net 221