From 0ab40dc1ab4e689921da54080b135e1d22b1c586 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?louiz=E2=80=99?= Date: Tue, 14 Mar 2017 21:45:23 +0100 Subject: Refactoring louloulibs and cmake Use OBJECT libraries Remove the louloulibs directory Write FOUND variables in the cache --- src/network/resolver.cpp | 281 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 281 insertions(+) create mode 100644 src/network/resolver.cpp (limited to 'src/network/resolver.cpp') diff --git a/src/network/resolver.cpp b/src/network/resolver.cpp new file mode 100644 index 0000000..db7fb32 --- /dev/null +++ b/src/network/resolver.cpp @@ -0,0 +1,281 @@ +#include +#include +#include +#include +#include +#include +#ifdef UDNS_FOUND +# include +#endif + +#include +#include +#include +#include +#include + +using namespace std::string_literals; + +#ifdef UDNS_FOUND +static std::map dns_error_messages { + {DNS_E_TEMPFAIL, "Timeout while contacting DNS servers"}, + {DNS_E_PROTOCOL, "Misformatted DNS reply"}, + {DNS_E_NXDOMAIN, "Domain name not found"}, + {DNS_E_NOMEM, "Out of memory"}, + {DNS_E_BADQUERY, "Misformatted domain name"} +}; +#endif + +Resolver::Resolver(): +#ifdef UDNS_FOUND + resolved4(false), + resolved6(false), + resolving(false), + port{}, +#endif + resolved(false), + error_msg{} +{ +} + +void Resolver::resolve(const std::string& hostname, const std::string& port, + SuccessCallbackType success_cb, ErrorCallbackType error_cb) +{ + this->error_cb = error_cb; + this->success_cb = success_cb; +#ifdef UDNS_FOUND + this->port = port; +#endif + + this->start_resolving(hostname, port); +} + +int Resolver::call_getaddrinfo(const char *name, const char* port, int flags) +{ + struct addrinfo hints; + memset(&hints, 0, sizeof(struct addrinfo)); + hints.ai_flags = flags; + hints.ai_family = AF_UNSPEC; + hints.ai_socktype = SOCK_STREAM; + hints.ai_protocol = 0; + + struct addrinfo* addr_res = nullptr; + const int res = ::getaddrinfo(name, port, + &hints, &addr_res); + + if (res == 0 && addr_res) + { + if (!this->addr) + this->addr.reset(addr_res); + else + { // Append this result at the end of the linked list + struct addrinfo *rp = this->addr.get(); + while (rp->ai_next) + rp = rp->ai_next; + rp->ai_next = addr_res; + } + } + + return res; +} + +#ifdef UDNS_FOUND +void Resolver::start_resolving(const std::string& hostname, const std::string& port) +{ + this->resolving = true; + this->resolved = false; + this->resolved4 = false; + this->resolved6 = false; + + this->error_msg.clear(); + this->addr.reset(nullptr); + + // We first try to use it as an IP address directly. We tell getaddrinfo + // to NOT use any DNS resolution. + if (this->call_getaddrinfo(hostname.data(), port.data(), AI_NUMERICHOST) == 0) + { + this->on_resolved(); + return; + } + + // Then we look into /etc/hosts to translate the given hostname + const auto hosts = this->look_in_etc_hosts(hostname); + if (!hosts.empty()) + { + for (const auto &host: hosts) + this->call_getaddrinfo(host.data(), port.data(), AI_NUMERICHOST); + this->on_resolved(); + return; + } + + // And finally, we try a DNS resolution + auto hostname6_resolved = [](dns_ctx*, dns_rr_a6* result, void* data) + { + Resolver* resolver = static_cast(data); + resolver->on_hostname6_resolved(result); + resolver->after_resolved(); + std::free(result); + }; + + auto hostname4_resolved = [](dns_ctx*, dns_rr_a4* result, void* data) + { + Resolver* resolver = static_cast(data); + resolver->on_hostname4_resolved(result); + resolver->after_resolved(); + std::free(result); + }; + + DNSHandler::watch(); + auto res = dns_submit_a4(nullptr, hostname.data(), 0, hostname4_resolved, this); + if (!res) + this->on_hostname4_resolved(nullptr); + res = dns_submit_a6(nullptr, hostname.data(), 0, hostname6_resolved, this); + if (!res) + this->on_hostname6_resolved(nullptr); + + this->start_timer(); +} + +void Resolver::start_timer() +{ + const auto timeout = dns_timeouts(nullptr, -1, 0); + if (timeout < 0) + return; + TimedEvent event(std::chrono::steady_clock::now() + std::chrono::seconds(timeout), [this]() { this->start_timer(); }, "DNS"); + TimedEventsManager::instance().add_event(std::move(event)); +} + +std::vector Resolver::look_in_etc_hosts(const std::string &hostname) +{ + std::ifstream hosts("/etc/hosts"); + std::string line; + + std::vector results; + while (std::getline(hosts, line)) + { + if (line.empty()) + continue; + + std::string ip; + std::istringstream line_stream(line); + line_stream >> ip; + if (ip.empty() || ip[0] == '#') + continue; + + std::string host; + while (line_stream >> host && !host.empty() && host[0] != '#') + { + if (hostname == host) + { + results.push_back(ip); + break; + } + } + } + return results; +} + +void Resolver::on_hostname4_resolved(dns_rr_a4 *result) +{ + this->resolved4 = true; + + const auto status = dns_status(nullptr); + + if (status >= 0 && result) + { + char buf[INET6_ADDRSTRLEN]; + + for (auto i = 0; i < result->dnsa4_nrr; ++i) + { + inet_ntop(AF_INET, &result->dnsa4_addr[i], buf, sizeof(buf)); + this->call_getaddrinfo(buf, this->port.data(), AI_NUMERICHOST); + } + } + else + { + const auto error = dns_error_messages.find(status); + if (error != end(dns_error_messages)) + this->error_msg = error->second; + } +} + +void Resolver::on_hostname6_resolved(dns_rr_a6 *result) +{ + this->resolved6 = true; + + const auto status = dns_status(nullptr); + + if (status >= 0 && result) + { + char buf[INET6_ADDRSTRLEN]; + for (auto i = 0; i < result->dnsa6_nrr; ++i) + { + inet_ntop(AF_INET6, &result->dnsa6_addr[i], buf, sizeof(buf)); + this->call_getaddrinfo(buf, this->port.data(), AI_NUMERICHOST); + } + } +} + +void Resolver::after_resolved() +{ + if (dns_active(nullptr) == 0) + DNSHandler::unwatch(); + + if (this->resolved6 && this->resolved4) + this->on_resolved(); +} + +void Resolver::on_resolved() +{ + this->resolved = true; + this->resolving = false; + if (!this->addr) + { + if (this->error_cb) + this->error_cb(this->error_msg.data()); + } + else + { + if (this->success_cb) + this->success_cb(this->addr.get()); + } +} + +#else // ifdef UDNS_FOUND + +void Resolver::start_resolving(const std::string& hostname, const std::string& port) +{ + // If the resolution fails, the addr will be unset + this->addr.reset(nullptr); + + const auto res = this->call_getaddrinfo(hostname.data(), port.data(), 0); + + this->resolved = true; + + if (res != 0) + { + this->error_msg = gai_strerror(res); + if (this->error_cb) + this->error_cb(this->error_msg.data()); + } + else + { + if (this->success_cb) + this->success_cb(this->addr.get()); + } +} +#endif // ifdef UDNS_FOUND + +std::string addr_to_string(const struct addrinfo* rp) +{ + char buf[INET6_ADDRSTRLEN]; + if (rp->ai_family == AF_INET) + return ::inet_ntop(rp->ai_family, + &reinterpret_cast(rp->ai_addr)->sin_addr, + buf, sizeof(buf)); + else if (rp->ai_family == AF_INET6) + return ::inet_ntop(rp->ai_family, + &reinterpret_cast(rp->ai_addr)->sin6_addr, + buf, sizeof(buf)); + return {}; +} -- cgit v1.2.3