274 lines
8.2 KiB
C
274 lines
8.2 KiB
C
/* -*- c-basic-offset: 4; indent-tabs-mode: nil; -*- */
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#include "config.h"
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#include <assert.h>
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#include <common/status.h>
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#include <connectd/netaddress.h>
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#include <errno.h>
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#include <netinet/in.h>
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#include <unistd.h>
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/* Based on bitcoin's src/netaddress.cpp, hence different naming and styling!
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version 7f31762cb6261806542cc6d1188ca07db98a6950:
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Copyright (c) 2009-2010 Satoshi Nakamoto
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Copyright (c) 2009-2016 The Bitcoin Core developers
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Distributed under the MIT software license, see the accompanying
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file COPYING or http://www.opensource.org/licenses/mit-license.php.
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*/
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/* The common IPv4-in-IPv6 prefix */
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static const unsigned char pchIPv4[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff };
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static bool IsRFC6145(const struct wireaddr *addr)
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{
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static const unsigned char pchRFC6145[] = {0,0,0,0,0,0,0,0,0xFF,0xFF,0,0};
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return addr->type == ADDR_TYPE_IPV6
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&& memcmp(addr->addr, pchRFC6145, sizeof(pchRFC6145)) == 0;
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}
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static bool IsRFC6052(const struct wireaddr *addr)
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{
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static const unsigned char pchRFC6052[] = {0,0x64,0xFF,0x9B,0,0,0,0,0,0,0,0};
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return addr->type == ADDR_TYPE_IPV6
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&& memcmp(addr->addr, pchRFC6052, sizeof(pchRFC6052)) == 0;
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}
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static bool IsRFC3964(const struct wireaddr *addr)
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{
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return addr->type == ADDR_TYPE_IPV6
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&& addr->addr[0] == 0x20 && addr->addr[1] == 0x02;
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}
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/* Return offset of IPv4 address, or 0 == not an IPv4 */
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static size_t IPv4In6(const struct wireaddr *addr)
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{
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if (addr->type != ADDR_TYPE_IPV6)
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return 0;
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if (memcmp(addr->addr, pchIPv4, sizeof(pchIPv4)) == 0)
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return sizeof(pchIPv4);
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if (IsRFC6052(addr))
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return 12;
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if (IsRFC6145(addr))
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return 12;
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if (IsRFC3964(addr))
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return 2;
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return 0;
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}
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/* Is this an IPv4 address, or an IPv6-wrapped IPv4 */
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static bool IsIPv4(const struct wireaddr *addr)
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{
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return addr->type == ADDR_TYPE_IPV4 || IPv4In6(addr) != 0;
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}
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static bool IsIPv6(const struct wireaddr *addr)
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{
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return addr->type == ADDR_TYPE_IPV6 && IPv4In6(addr) == 0;
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}
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static bool RawEq(const struct wireaddr *addr, const void *cmp, size_t len)
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{
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size_t off = IPv4In6(addr);
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assert(off + len <= addr->addrlen);
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return memcmp(addr->addr + off, cmp, len) == 0;
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}
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/* The bitcoin code packs addresses backwards, so we map it here. */
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static unsigned int GetByte(const struct wireaddr *addr, int n)
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{
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size_t off = IPv4In6(addr);
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assert(off + n < addr->addrlen);
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return addr->addr[addr->addrlen - 1 - off - n];
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}
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static bool IsRFC1918(const struct wireaddr *addr)
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{
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return IsIPv4(addr) && (
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GetByte(addr, 3) == 10 ||
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(GetByte(addr, 3) == 192 && GetByte(addr, 2) == 168) ||
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(GetByte(addr, 3) == 172 && (GetByte(addr, 2) >= 16 && GetByte(addr, 2) <= 31)));
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}
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static bool IsRFC2544(const struct wireaddr *addr)
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{
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return IsIPv4(addr) && GetByte(addr, 3) == 198 && (GetByte(addr, 2) == 18 || GetByte(addr, 2) == 19);
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}
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static bool IsRFC3927(const struct wireaddr *addr)
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{
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return IsIPv4(addr) && (GetByte(addr, 3) == 169 && GetByte(addr, 2) == 254);
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}
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static bool IsRFC6598(const struct wireaddr *addr)
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{
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return IsIPv4(addr) && GetByte(addr, 3) == 100 && GetByte(addr, 2) >= 64 && GetByte(addr, 2) <= 127;
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}
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static bool IsRFC5737(const struct wireaddr *addr)
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{
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return IsIPv4(addr) && ((GetByte(addr, 3) == 192 && GetByte(addr, 2) == 0 && GetByte(addr, 1) == 2) ||
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(GetByte(addr, 3) == 198 && GetByte(addr, 2) == 51 && GetByte(addr, 1) == 100) ||
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(GetByte(addr, 3) == 203 && GetByte(addr, 2) == 0 && GetByte(addr, 1) == 113));
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}
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static bool IsRFC3849(const struct wireaddr *addr)
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{
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return IsIPv6(addr) && GetByte(addr, 15) == 0x20 && GetByte(addr, 14) == 0x01 && GetByte(addr, 13) == 0x0D && GetByte(addr, 12) == 0xB8;
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}
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static bool IsRFC4862(const struct wireaddr *addr)
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{
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static const unsigned char pchRFC4862[] = {0xFE,0x80,0,0,0,0,0,0};
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return IsIPv6(addr) && RawEq(addr, pchRFC4862, sizeof(pchRFC4862));
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}
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static bool IsRFC4193(const struct wireaddr *addr)
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{
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return IsIPv6(addr) && ((GetByte(addr, 15) & 0xFE) == 0xFC);
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}
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static bool IsRFC4843(const struct wireaddr *addr)
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{
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return IsIPv6(addr) && (GetByte(addr, 15) == 0x20 && GetByte(addr, 14) == 0x01 && GetByte(addr, 13) == 0x00 && (GetByte(addr, 12) & 0xF0) == 0x10);
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}
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static bool IsTor(const struct wireaddr *addr)
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{
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return addr->type == ADDR_TYPE_TOR_V3;
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}
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static bool IsLocal(const struct wireaddr *addr)
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{
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// IPv4 loopback
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if (IsIPv4(addr) && (GetByte(addr, 3) == 127 || GetByte(addr, 3) == 0))
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return true;
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// IPv6 loopback (::1/128)
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static const unsigned char pchLocal[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
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if (IsIPv6(addr) && RawEq(addr, pchLocal, sizeof(pchLocal)))
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return true;
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return false;
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}
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static bool IsInternal(const struct wireaddr *addr)
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{
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return false;
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}
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static bool IsValid(const struct wireaddr *addr)
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{
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// unspecified IPv6 address (::/128)
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unsigned char ipNone6[16] = {};
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if (IsIPv6(addr) && RawEq(addr, ipNone6, sizeof(ipNone6)))
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return false;
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// documentation IPv6 address
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if (IsRFC3849(addr))
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return false;
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if (IsInternal(addr))
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return false;
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if (IsIPv4(addr))
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{
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// INADDR_NONE
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uint32_t ipNone = INADDR_NONE;
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if (RawEq(addr, &ipNone, sizeof(ipNone)))
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return false;
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// 0
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ipNone = 0;
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if (RawEq(addr, &ipNone, sizeof(ipNone)))
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return false;
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}
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return true;
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}
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static bool IsRoutable(const struct wireaddr *addr)
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{
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return IsValid(addr) && !(IsRFC1918(addr) || IsRFC2544(addr) || IsRFC3927(addr) || IsRFC4862(addr) || IsRFC6598(addr) || IsRFC5737(addr) || (IsRFC4193(addr) && !IsTor(addr)) || IsRFC4843(addr) || IsLocal(addr) || IsInternal(addr));
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}
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/* Trick I learned from Harald Welte: create UDP socket, connect() and
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* then query address. */
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/* Returns 0 if protocol completely unsupported, ADDR_LISTEN if we
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* can't reach addr, ADDR_LISTEN_AND_ANNOUNCE if we can (and fill saddr). */
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static bool get_local_sockname(int af, void *saddr, socklen_t saddrlen)
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{
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int fd = socket(af, SOCK_DGRAM, 0);
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if (fd < 0) {
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status_debug("Failed to create %u socket: %s",
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af, strerror(errno));
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return false;
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}
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if (connect(fd, saddr, saddrlen) != 0) {
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status_debug("Failed to connect %u socket: %s",
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af, strerror(errno));
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close(fd);
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return false;
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}
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if (getsockname(fd, saddr, &saddrlen) != 0) {
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status_debug("Failed to get %u socket name: %s",
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af, strerror(errno));
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close(fd);
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return false;
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}
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close(fd);
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return true;
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}
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bool guess_address(struct wireaddr *addr)
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{
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bool ret;
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/* We point to Google nameservers, works unless you're inside Google :) */
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switch (addr->type) {
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case ADDR_TYPE_IPV4: {
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struct sockaddr_in sin;
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memset(&sin, 0, sizeof(sin));
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sin.sin_port = htons(53);
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/* 8.8.8.8 */
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sin.sin_addr.s_addr = 0x08080808;
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sin.sin_family = AF_INET;
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ret = get_local_sockname(AF_INET, &sin, sizeof(sin));
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addr->addrlen = sizeof(sin.sin_addr);
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memcpy(addr->addr, &sin.sin_addr, addr->addrlen);
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return ret;
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}
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case ADDR_TYPE_IPV6: {
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struct sockaddr_in6 sin6;
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memset(&sin6, 0, sizeof(sin6));
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/* 2001:4860:4860::8888 */
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static const unsigned char pchGoogle[16]
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= {0x20,0x01,0x48,0x60,0x48,0x60,0,0,0,0,0,0,8,8,8,8};
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memset(&sin6, 0, sizeof(sin6));
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sin6.sin6_port = htons(53);
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sin6.sin6_family = AF_INET6;
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memcpy(sin6.sin6_addr.s6_addr, pchGoogle, sizeof(pchGoogle));
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ret = get_local_sockname(AF_INET6, &sin6, sizeof(sin6));
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addr->addrlen = sizeof(sin6.sin6_addr);
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memcpy(addr->addr, &sin6.sin6_addr, addr->addrlen);
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return ret;
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}
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case ADDR_TYPE_TOR_V2_REMOVED:
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case ADDR_TYPE_TOR_V3:
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case ADDR_TYPE_DNS:
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status_broken("Cannot guess address type %u", addr->type);
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break;
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}
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abort();
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}
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bool address_routable(const struct wireaddr *wireaddr, bool allow_localhost)
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{
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if (allow_localhost && IsLocal(wireaddr))
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return true;
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return IsRoutable(wireaddr);
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}
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