// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Taken from WebRTC's own implementation.
// https://webrtc.googlesource.com/src/+/4cad08ff199a46087f8ffe91ef89af60a4dc8df9/rtc_base/ifaddrs_android.cc
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40284755): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif
#include "build/build_config.h"
#if BUILDFLAG(IS_ANDROID)
#include "net/base/network_interfaces_getifaddrs_android.h"
#include <errno.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <net/if.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <unistd.h>
#include "base/scoped_generic.h"
namespace net::internal {
namespace {
struct netlinkrequest {
nlmsghdr header;
ifaddrmsg msg;
};
const int kMaxReadSize = 4096;
struct FdTraits {
static int InvalidValue() { return -1; }
static void Free(int f) { ::close(f); }
};
struct IfaddrsTraits {
static struct ifaddrs* InvalidValue() { return nullptr; }
static void Free(struct ifaddrs* ifaddrs) { Freeifaddrs(ifaddrs); }
};
int set_ifname(struct ifaddrs* ifaddr, int interface) {
char buf[IFNAMSIZ] = {0};
char* name = if_indextoname(interface, buf);
if (name == nullptr) {
return -1;
}
ifaddr->ifa_name = new char[strlen(name) + 1];
strncpy(ifaddr->ifa_name, name, strlen(name) + 1);
return 0;
}
int set_flags(struct ifaddrs* ifaddr) {
int fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
return -1;
}
ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, ifaddr->ifa_name, IFNAMSIZ - 1);
int rc = ioctl(fd, SIOCGIFFLAGS, &ifr);
close(fd);
if (rc == -1) {
return -1;
}
ifaddr->ifa_flags = ifr.ifr_flags;
return 0;
}
int set_addresses(struct ifaddrs* ifaddr,
ifaddrmsg* msg,
void* data,
size_t len) {
if (msg->ifa_family == AF_INET) {
sockaddr_in* sa = new sockaddr_in;
sa->sin_family = AF_INET;
memcpy(&sa->sin_addr, data, len);
ifaddr->ifa_addr = reinterpret_cast<sockaddr*>(sa);
} else if (msg->ifa_family == AF_INET6) {
sockaddr_in6* sa = new sockaddr_in6;
sa->sin6_family = AF_INET6;
sa->sin6_scope_id = msg->ifa_index;
memcpy(&sa->sin6_addr, data, len);
ifaddr->ifa_addr = reinterpret_cast<sockaddr*>(sa);
} else {
return -1;
}
return 0;
}
int make_prefixes(struct ifaddrs* ifaddr, int family, int prefixlen) {
char* prefix = nullptr;
if (family == AF_INET) {
sockaddr_in* mask = new sockaddr_in;
mask->sin_family = AF_INET;
memset(&mask->sin_addr, 0, sizeof(in_addr));
ifaddr->ifa_netmask = reinterpret_cast<sockaddr*>(mask);
if (prefixlen > 32) {
prefixlen = 32;
}
prefix = reinterpret_cast<char*>(&mask->sin_addr);
} else if (family == AF_INET6) {
sockaddr_in6* mask = new sockaddr_in6;
mask->sin6_family = AF_INET6;
memset(&mask->sin6_addr, 0, sizeof(in6_addr));
ifaddr->ifa_netmask = reinterpret_cast<sockaddr*>(mask);
if (prefixlen > 128) {
prefixlen = 128;
}
prefix = reinterpret_cast<char*>(&mask->sin6_addr);
} else {
return -1;
}
for (int i = 0; i < (prefixlen / 8); i++) {
*prefix++ = 0xFF;
}
char remainder = 0xff;
remainder <<= (8 - prefixlen % 8);
*prefix = remainder;
return 0;
}
int populate_ifaddrs(struct ifaddrs* ifaddr,
ifaddrmsg* msg,
void* bytes,
size_t len) {
if (set_ifname(ifaddr, msg->ifa_index) != 0) {
return -1;
}
if (set_flags(ifaddr) != 0) {
return -1;
}
if (set_addresses(ifaddr, msg, bytes, len) != 0) {
return -1;
}
if (make_prefixes(ifaddr, msg->ifa_family, msg->ifa_prefixlen) != 0) {
return -1;
}
return 0;
}
} // namespace
int Getifaddrs(struct ifaddrs** result) {
int fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (fd < 0) {
*result = nullptr;
return -1;
}
base::ScopedGeneric<int, FdTraits> scoped_fd(fd);
base::ScopedGeneric<struct ifaddrs*, IfaddrsTraits> scoped_ifaddrs;
netlinkrequest ifaddr_request;
memset(&ifaddr_request, 0, sizeof(ifaddr_request));
ifaddr_request.header.nlmsg_flags = NLM_F_ROOT | NLM_F_REQUEST;
ifaddr_request.header.nlmsg_type = RTM_GETADDR;
ifaddr_request.header.nlmsg_len = NLMSG_LENGTH(sizeof(ifaddrmsg));
ssize_t count = send(fd, &ifaddr_request, ifaddr_request.header.nlmsg_len, 0);
if (static_cast<size_t>(count) != ifaddr_request.header.nlmsg_len) {
close(fd);
return -1;
}
struct ifaddrs* current = nullptr;
char buf[kMaxReadSize];
ssize_t amount_read = recv(fd, &buf, kMaxReadSize, 0);
while (amount_read > 0) {
nlmsghdr* header = reinterpret_cast<nlmsghdr*>(&buf[0]);
size_t header_size = static_cast<size_t>(amount_read);
for (; NLMSG_OK(header, header_size);
header = NLMSG_NEXT(header, header_size)) {
switch (header->nlmsg_type) {
case NLMSG_DONE:
// Success. Return.
*result = scoped_ifaddrs.release();
return 0;
case NLMSG_ERROR:
*result = nullptr;
return -1;
case RTM_NEWADDR: {
ifaddrmsg* address_msg =
reinterpret_cast<ifaddrmsg*>(NLMSG_DATA(header));
rtattr* rta = IFA_RTA(address_msg);
ssize_t payload_len = IFA_PAYLOAD(header);
while (RTA_OK(rta, payload_len)) {
if ((address_msg->ifa_family == AF_INET &&
rta->rta_type == IFA_LOCAL) ||
(address_msg->ifa_family == AF_INET6 &&
rta->rta_type == IFA_ADDRESS)) {
ifaddrs* newest = new ifaddrs;
memset(newest, 0, sizeof(ifaddrs));
if (current) {
current->ifa_next = newest;
} else {
scoped_ifaddrs.reset(newest);
}
if (populate_ifaddrs(newest, address_msg, RTA_DATA(rta),
RTA_PAYLOAD(rta)) != 0) {
*result = nullptr;
return -1;
}
current = newest;
}
rta = RTA_NEXT(rta, payload_len);
}
break;
}
}
}
amount_read = recv(fd, &buf, kMaxReadSize, 0);
}
*result = nullptr;
return -1;
}
void Freeifaddrs(struct ifaddrs* addrs) {
struct ifaddrs* last = nullptr;
struct ifaddrs* cursor = addrs;
while (cursor) {
delete[] cursor->ifa_name;
delete cursor->ifa_addr;
delete cursor->ifa_netmask;
last = cursor;
cursor = cursor->ifa_next;
delete last;
}
}
} // namespace net::internal
#endif // BUILDFLAG(IS_ANDROID)
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