michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 et sw=2 tw=80: */
michael@0: /*
michael@0:  * Copyright (C) 2009 The Android Open Source Project
michael@0:  *
michael@0:  * Licensed under the Apache License, Version 2.0 (the "License");
michael@0:  * you may not use this file except in compliance with the License.
michael@0:  * You may obtain a copy of the License at
michael@0:  *
michael@0:  *      http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing, software
michael@0:  * distributed under the License is distributed on an "AS IS" BASIS,
michael@0:  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
michael@0:  * See the License for the specific language governing permissions and
michael@0:  * limitations under the License.
michael@0:  */
michael@0: 
michael@0: #include "ifaddrs-android-ext.h"
michael@0: 
michael@0: #include <stdlib.h>
michael@0: #include <string.h>
michael@0: #include "ScopedFd.h"
michael@0: #include "LocalArray.h"
michael@0: 
michael@0: // Returns a pointer to the first byte in the address data (which is
michael@0: // stored in network byte order).
michael@0: uint8_t* sockaddrBytes(int family, sockaddr_storage* ss) {
michael@0:     if (family == AF_INET) {
michael@0:         sockaddr_in* ss4 = reinterpret_cast<sockaddr_in*>(ss);
michael@0:         return reinterpret_cast<uint8_t*>(&ss4->sin_addr);
michael@0:     } else if (family == AF_INET6) {
michael@0:         sockaddr_in6* ss6 = reinterpret_cast<sockaddr_in6*>(ss);
michael@0:         return reinterpret_cast<uint8_t*>(&ss6->sin6_addr);
michael@0:     }
michael@0:     return NULL;
michael@0: }
michael@0: 
michael@0: // Sadly, we can't keep the interface index for portability with BSD.
michael@0: // We'll have to keep the name instead, and re-query the index when
michael@0: // we need it later.
michael@0: bool ifa_setNameAndFlagsByIndex(ifaddrs *self, int interfaceIndex) {
michael@0:     // Get the name.
michael@0:     char buf[IFNAMSIZ];
michael@0:     char* name = if_indextoname(interfaceIndex, buf);
michael@0:     if (name == NULL) {
michael@0:         return false;
michael@0:     }
michael@0:     self->ifa_name = new char[strlen(name) + 1];
michael@0:     strcpy(self->ifa_name, name);
michael@0: 
michael@0:     // Get the flags.
michael@0:     ScopedFd fd(socket(AF_INET, SOCK_DGRAM, 0));
michael@0:     if (fd.get() == -1) {
michael@0:         return false;
michael@0:     }
michael@0:     ifreq ifr;
michael@0:     memset(&ifr, 0, sizeof(ifr));
michael@0:     strcpy(ifr.ifr_name, name);
michael@0:     int rc = ioctl(fd.get(), SIOCGIFFLAGS, &ifr);
michael@0:     if (rc == -1) {
michael@0:         return false;
michael@0:     }
michael@0:     self->ifa_flags = ifr.ifr_flags;
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: // Netlink gives us the address family in the header, and the
michael@0: // sockaddr_in or sockaddr_in6 bytes as the payload. We need to
michael@0: // stitch the two bits together into the sockaddr that's part of
michael@0: // our portable interface.
michael@0: void ifa_setAddress(ifaddrs *self, int family, void* data, size_t byteCount) {
michael@0:     // Set the address proper...
michael@0:     sockaddr_storage* ss = new sockaddr_storage;
michael@0:     memset(ss, 0, sizeof(*ss));
michael@0:     self->ifa_addr = reinterpret_cast<sockaddr*>(ss);
michael@0:     ss->ss_family = family;
michael@0:     uint8_t* dst = sockaddrBytes(family, ss);
michael@0:     memcpy(dst, data, byteCount);
michael@0: }
michael@0: 
michael@0: // Netlink gives us the prefix length as a bit count. We need to turn
michael@0: // that into a BSD-compatible netmask represented by a sockaddr*.
michael@0: void ifa_setNetmask(ifaddrs *self, int family, size_t prefixLength) {
michael@0:     // ...and work out the netmask from the prefix length.
michael@0:     sockaddr_storage* ss = new sockaddr_storage;
michael@0:     memset(ss, 0, sizeof(*ss));
michael@0:     self->ifa_netmask = reinterpret_cast<sockaddr*>(ss);
michael@0:     ss->ss_family = family;
michael@0:     uint8_t* dst = sockaddrBytes(family, ss);
michael@0:     memset(dst, 0xff, prefixLength / 8);
michael@0:     if ((prefixLength % 8) != 0) {
michael@0:         dst[prefixLength/8] = (0xff << (8 - (prefixLength % 8)));
michael@0:     }
michael@0: }
michael@0: 
michael@0: // FIXME: use iovec instead.
michael@0: struct addrReq_struct {
michael@0:     nlmsghdr netlinkHeader;
michael@0:     ifaddrmsg msg;
michael@0: };
michael@0: 
michael@0: inline bool sendNetlinkMessage(int fd, const void* data, size_t byteCount) {
michael@0:     ssize_t sentByteCount = TEMP_FAILURE_RETRY(send(fd, data, byteCount, 0));
michael@0:     return (sentByteCount == static_cast<ssize_t>(byteCount));
michael@0: }
michael@0: 
michael@0: inline ssize_t recvNetlinkMessage(int fd, char* buf, size_t byteCount) {
michael@0:     return TEMP_FAILURE_RETRY(recv(fd, buf, byteCount, 0));
michael@0: }
michael@0: 
michael@0: // Source-compatible with the BSD function.
michael@0: int getifaddrs(ifaddrs** result)
michael@0: {
michael@0:     // Simplify cleanup for callers.
michael@0:     *result = NULL;
michael@0: 
michael@0:     // Create a netlink socket.
michael@0:     ScopedFd fd(socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE));
michael@0:     if (fd.get() < 0) {
michael@0:         return -1;
michael@0:     }
michael@0: 
michael@0:     // Ask for the address information.
michael@0:     addrReq_struct addrRequest;
michael@0:     memset(&addrRequest, 0, sizeof(addrRequest));
michael@0:     addrRequest.netlinkHeader.nlmsg_flags = NLM_F_REQUEST | NLM_F_MATCH;
michael@0:     addrRequest.netlinkHeader.nlmsg_type = RTM_GETADDR;
michael@0:     addrRequest.netlinkHeader.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(addrRequest)));
michael@0:     addrRequest.msg.ifa_family = AF_UNSPEC; // All families.
michael@0:     addrRequest.msg.ifa_index = 0; // All interfaces.
michael@0:     if (!sendNetlinkMessage(fd.get(), &addrRequest, addrRequest.netlinkHeader.nlmsg_len)) {
michael@0:         return -1;
michael@0:     }
michael@0: 
michael@0:     // Read the responses.
michael@0:     LocalArray<0> buf(65536); // We don't necessarily have std::vector.
michael@0:     ssize_t bytesRead;
michael@0:     while ((bytesRead  = recvNetlinkMessage(fd.get(), &buf[0], buf.size())) > 0) {
michael@0:         nlmsghdr* hdr = reinterpret_cast<nlmsghdr*>(&buf[0]);
michael@0:         for (; NLMSG_OK(hdr, (size_t)bytesRead); hdr = NLMSG_NEXT(hdr, bytesRead)) {
michael@0:             switch (hdr->nlmsg_type) {
michael@0:             case NLMSG_DONE:
michael@0:                 return 0;
michael@0:             case NLMSG_ERROR:
michael@0:                 return -1;
michael@0:             case RTM_NEWADDR:
michael@0:                 {
michael@0:                     ifaddrmsg* address = reinterpret_cast<ifaddrmsg*>(NLMSG_DATA(hdr));
michael@0:                     rtattr* rta = IFA_RTA(address);
michael@0:                     size_t ifaPayloadLength = IFA_PAYLOAD(hdr);
michael@0:                     while (RTA_OK(rta, ifaPayloadLength)) {
michael@0:                         if (rta->rta_type == IFA_LOCAL) {
michael@0:                             int family = address->ifa_family;
michael@0:                             if (family == AF_INET || family == AF_INET6) {
michael@0:                                 ifaddrs *next = *result;
michael@0:                                 *result = new ifaddrs;
michael@0:                                 memset(*result, 0, sizeof(ifaddrs));
michael@0:                                 (*result)->ifa_next = next;
michael@0:                                 if (!ifa_setNameAndFlagsByIndex(*result, address->ifa_index)) {
michael@0:                                     return -1;
michael@0:                                 }
michael@0:                                 ifa_setAddress(*result, family, RTA_DATA(rta), RTA_PAYLOAD(rta));
michael@0:                                 ifa_setNetmask(*result, family, address->ifa_prefixlen);
michael@0:                             }
michael@0:                         }
michael@0:                         rta = RTA_NEXT(rta, ifaPayloadLength);
michael@0:                     }
michael@0:                 }
michael@0:                 break;
michael@0:             }
michael@0:         }
michael@0:     }
michael@0:     // We only get here if recv fails before we see a NLMSG_DONE.
michael@0:     return -1;
michael@0: }
michael@0: 
michael@0: // Source-compatible with the BSD function.
michael@0: void freeifaddrs(ifaddrs* addresses) {
michael@0:     ifaddrs* self = addresses;
michael@0:     while (self != NULL) {
michael@0:         delete[] self->ifa_name;
michael@0:         delete self->ifa_addr;
michael@0:         delete self->ifa_netmask;
michael@0:         ifaddrs* next = self->ifa_next;
michael@0:         delete self;
michael@0:         self = next;
michael@0:     }
michael@0: }