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Diffstat (limited to 'host/commands/assemble_cvd/network_flags.cpp')
| -rw-r--r-- | host/commands/assemble_cvd/network_flags.cpp | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/host/commands/assemble_cvd/network_flags.cpp b/host/commands/assemble_cvd/network_flags.cpp new file mode 100644 index 000000000..055bd94b5 --- /dev/null +++ b/host/commands/assemble_cvd/network_flags.cpp @@ -0,0 +1,160 @@ +/* + * Copyright (C) 2024 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "host/commands/assemble_cvd/network_flags.h" + +#include <arpa/inet.h> +#include <ifaddrs.h> + +#include <android-base/logging.h> + +namespace cuttlefish { +namespace { + +uint8_t number_of_ones(unsigned long val) { + uint8_t ret = 0; + while (val) { + ret += val % 2; + val >>= 1; + } + return ret; +} + +class NetConfig { + public: + uint8_t ril_prefixlen = -1; + std::string ril_ipaddr; + std::string ril_gateway; + std::string ril_dns; + std::string ril_broadcast; + + bool ObtainConfig(const std::string& interface, const std::string& dns) { + bool ret = ParseInterfaceAttributes(interface); + if (ret) { + ril_dns = dns; + LOG(DEBUG) << "Network config:"; + LOG(DEBUG) << "ipaddr = " << ril_ipaddr; + LOG(DEBUG) << "gateway = " << ril_gateway; + LOG(DEBUG) << "dns = " << ril_dns; + LOG(DEBUG) << "broadcast = " << ril_broadcast; + LOG(DEBUG) << "prefix length = " << static_cast<int>(ril_prefixlen); + } + return ret; + } + + private: + bool ParseInterfaceAttributes(struct ifaddrs* ifa) { + struct sockaddr_in* sa; + char* addr_str; + + // Gateway + sa = reinterpret_cast<sockaddr_in*>(ifa->ifa_addr); + addr_str = inet_ntoa(sa->sin_addr); + this->ril_gateway = strtok(addr_str, "\n"); + auto gateway_s_addr = ntohl(sa->sin_addr.s_addr); + + // Broadcast + sa = reinterpret_cast<sockaddr_in*>(ifa->ifa_broadaddr); + addr_str = inet_ntoa(sa->sin_addr); + this->ril_broadcast = strtok(addr_str, "\n"); + auto broadcast_s_addr = ntohl(sa->sin_addr.s_addr); + + // Detect misconfigured network interfaces. All network interfaces must + // have a valid broadcast address set; if there is none set, glibc may + // return the interface address in the broadcast field. This causes + // no packets to be routed correctly from the guest. + if (this->ril_gateway == this->ril_broadcast) { + LOG(ERROR) << "Gateway and Broadcast addresses are the same on " + << ifa->ifa_name << ", which is invalid."; + return false; + } + + // Netmask + sa = reinterpret_cast<sockaddr_in*>(ifa->ifa_netmask); + this->ril_prefixlen = number_of_ones(sa->sin_addr.s_addr); + auto netmask_s_addr = ntohl(sa->sin_addr.s_addr); + + // Address (Find an address in the network different than the network, the + // gateway and the broadcast) + auto network = gateway_s_addr & netmask_s_addr; + auto s_addr = network + 1; + // s_addr & ~netmask_s_addr is zero when s_addr wraps around the network + while (s_addr & ~netmask_s_addr) { + if (s_addr != gateway_s_addr && s_addr != broadcast_s_addr) { + break; + } + ++s_addr; + } + if (s_addr == network) { + LOG(ERROR) << "No available address found in interface " << ifa->ifa_name; + return false; + } + struct in_addr addr; + addr.s_addr = htonl(s_addr); + addr_str = inet_ntoa(addr); + this->ril_ipaddr = strtok(addr_str, "\n"); + return true; + } + + bool ParseInterfaceAttributes(const std::string& interface) { + struct ifaddrs *ifa_list{}, *ifa{}; + bool ret = false; + getifaddrs(&ifa_list); + for (ifa = ifa_list; ifa; ifa = ifa->ifa_next) { + if (strcmp(ifa->ifa_name, interface.c_str()) == 0 && + ifa->ifa_addr->sa_family == AF_INET) { + ret = ParseInterfaceAttributes(ifa); + break; + } + } + freeifaddrs(ifa_list); + return ret; + } +}; + +} // namespace + +Result<void> ConfigureNetworkSettings( + const std::string& ril_dns_arg, + const CuttlefishConfig::InstanceSpecific& const_instance, + CuttlefishConfig::MutableInstanceSpecific& instance) { + NetConfig netconfig; + // Check the mobile bridge first; this was the traditional way we configured + // the mobile interface. If that fails, it probably means we are using a + // newer version of cuttlefish-common, and we can use the tap device + // directly instead. + if (!netconfig.ObtainConfig(const_instance.mobile_bridge_name(), + ril_dns_arg)) { + if (!netconfig.ObtainConfig(const_instance.mobile_tap_name(), + ril_dns_arg)) { + LOG(ERROR) << "Unable to get the network config. Assuming defaults."; + instance.set_ril_dns("8.8.8.8"); + instance.set_ril_gateway("10.0.2.2"); + instance.set_ril_ipaddr("10.0.2.15"); + instance.set_ril_prefixlen(24); + } + } + + instance.set_ril_broadcast(netconfig.ril_broadcast); + instance.set_ril_dns(netconfig.ril_dns); + instance.set_ril_gateway(netconfig.ril_gateway); + instance.set_ril_ipaddr(netconfig.ril_ipaddr); + instance.set_ril_prefixlen(netconfig.ril_prefixlen); + + return {}; +} + +} // namespace cuttlefish
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