diff options
| author | warptangent <warptangent@tutanota.com> | 2015-12-15 09:23:17 -0800 |
|---|---|---|
| committer | warptangent <warptangent@tutanota.com> | 2015-12-15 10:13:16 -0800 |
| commit | 0d40de48c2da9cd24fa656500034f64baf87fd89 (patch) | |
| tree | 07cf315e63a5369efe1a60ff1f8c6ef059b98e49 | |
| parent | Fix typo (diff) | |
| download | monero-0d40de48c2da9cd24fa656500034f64baf87fd89.tar.xz | |
Optionally restrict DNS queries to TCP
Sample use:
DNS_PUBLIC=tcp torsocks bin/bitmonerod --p2p-bind-ip 127.0.0.1
Test:
Run above with --log-level 4 with and without DNS_PUBLIC environment
variable set.
DNS debugging info should show successful DNS lookups only when
DNS_PUBLIC is set to "tcp":
DNS lookup for seeds.moneroseeds.se: 17 results
DNS lookup for seeds.moneroseeds.ae.org: 17 results
DNS lookup for seeds.moneroseeds.ch: 12 results
DNS lookup for seeds.moneroseeds.li: 12 results
| -rw-r--r-- | src/common/dns_utils.cpp | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/src/common/dns_utils.cpp b/src/common/dns_utils.cpp index 2ae5d9624..41cce68d8 100644 --- a/src/common/dns_utils.cpp +++ b/src/common/dns_utils.cpp @@ -183,12 +183,33 @@ struct DNSResolverData DNSResolver::DNSResolver() : m_data(new DNSResolverData()) { + int use_dns_public = 0; + const char* dns_public_addr = "8.8.4.4"; + if (auto res = getenv("DNS_PUBLIC")) + { + std::string dns_public(res); + // TODO: could allow parsing of IP and protocol: e.g. DNS_PUBLIC=tcp:8.8.8.8 + if (dns_public == "tcp") + { + LOG_PRINT_L0("Using public DNS server: " << dns_public_addr << " (TCP)"); + use_dns_public = 1; + } + } + // init libunbound context m_data->m_ub_context = ub_ctx_create(); - // look for "/etc/resolv.conf" and "/etc/hosts" or platform equivalent - ub_ctx_resolvconf(m_data->m_ub_context, NULL); - ub_ctx_hosts(m_data->m_ub_context, NULL); + if (use_dns_public) + { + ub_ctx_set_fwd(m_data->m_ub_context, dns_public_addr); + ub_ctx_set_option(m_data->m_ub_context, "do-udp:", "no"); + ub_ctx_set_option(m_data->m_ub_context, "do-tcp:", "yes"); + } + else { + // look for "/etc/resolv.conf" and "/etc/hosts" or platform equivalent + ub_ctx_resolvconf(m_data->m_ub_context, NULL); + ub_ctx_hosts(m_data->m_ub_context, NULL); + } #ifdef DEVELOPER_LIBUNBOUND_OLD #pragma message "Using the work around for old libunbound" |