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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#include "pal_config.h"
#include "pal_errno.h"
#include "pal_networkchange.h"
#include "pal_types.h"
#include "pal_utilities.h"
#include <errno.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#if HAVE_LINUX_RTNETLINK_H
#include <linux/rtnetlink.h>
#elif HAVE_RT_MSGHDR
#if HAVE_IOS_NET_ROUTE_H
#include "ios/net/route.h"
#else
#include <net/route.h>
#endif
#endif
#pragma clang diagnostic ignored "-Wcast-align" // NLMSG_* macros trigger this
Error SystemNative_CreateNetworkChangeListenerSocket(int32_t* retSocket)
{
#if HAVE_LINUX_RTNETLINK_H
struct sockaddr_nl sa;
memset(&sa, 0, sizeof(struct sockaddr_nl));
sa.nl_family = AF_NETLINK;
sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE;
int32_t sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
#elif HAVE_RT_MSGHDR
int32_t sock = socket(PF_ROUTE, SOCK_RAW, 0);
#endif
if (sock == -1)
{
*retSocket = -1;
return (Error)(SystemNative_ConvertErrorPlatformToPal(errno));
}
#if HAVE_LINUX_RTNETLINK_H
if (bind(sock, (struct sockaddr*)(&sa), sizeof(sa)) != 0)
{
*retSocket = -1;
Error palError = (Error)(SystemNative_ConvertErrorPlatformToPal(errno));
close(sock);
return palError;
}
#endif
*retSocket = sock;
return Error_SUCCESS;
}
Error SystemNative_CloseNetworkChangeListenerSocket(int32_t socket)
{
int err = close(socket);
return err == 0 || CheckInterrupted(err) ? Error_SUCCESS : (Error)(SystemNative_ConvertErrorPlatformToPal(errno));
}
#if HAVE_LINUX_RTNETLINK_H
static NetworkChangeKind ReadNewLinkMessage(struct nlmsghdr* hdr)
{
assert(hdr != NULL);
struct ifinfomsg* ifimsg;
ifimsg = (struct ifinfomsg*)NLMSG_DATA(hdr);
if (ifimsg->ifi_family == AF_UNSPEC)
{
return AvailabilityChanged;
}
return None;
}
void SystemNative_ReadEvents(int32_t sock, NetworkChangeEvent onNetworkChange)
{
char buffer[4096];
struct iovec iov = {buffer, sizeof(buffer)};
struct sockaddr_nl sanl;
struct msghdr msg = { .msg_name = (void*)(&sanl), .msg_namelen = sizeof(struct sockaddr_nl), .msg_iov = &iov, .msg_iovlen = 1 };
ssize_t len;
while (CheckInterrupted(len = recvmsg(sock, &msg, 0)));
if (len == -1)
{
// Probably means the socket has been closed.
return;
}
assert(len >= 0);
for (struct nlmsghdr* hdr = (struct nlmsghdr*)buffer; NLMSG_OK(hdr, (size_t)len); NLMSG_NEXT(hdr, len))
{
switch (hdr->nlmsg_type)
{
case NLMSG_DONE:
return; // End of a multi-part message; stop reading.
case NLMSG_ERROR:
return;
case RTM_NEWADDR:
onNetworkChange(sock, AddressAdded);
break;
case RTM_DELADDR:
onNetworkChange(sock, AddressRemoved);
break;
case RTM_NEWLINK:
onNetworkChange(sock, ReadNewLinkMessage(hdr));
break;
case RTM_NEWROUTE:
case RTM_DELROUTE:
{
struct rtmsg* dataAsRtMsg = (struct rtmsg*)NLMSG_DATA(hdr);
if (dataAsRtMsg->rtm_table == RT_TABLE_MAIN)
{
onNetworkChange(sock, AvailabilityChanged);
return;
}
break;
}
default:
break;
}
}
}
#elif HAVE_RT_MSGHDR
void SystemNative_ReadEvents(int32_t sock, NetworkChangeEvent onNetworkChange)
{
char buffer[4096];
ssize_t count = read(sock, buffer, sizeof(buffer));
if (count < 0)
{
return;
}
struct rt_msghdr msghdr;
for (char *ptr = buffer; (ptr + sizeof(struct rt_msghdr)) <= (buffer + count); ptr += msghdr.rtm_msglen)
{
memcpy(&msghdr, ptr, sizeof(msghdr));
if (msghdr.rtm_version != RTM_VERSION)
{
// version mismatch
return;
}
switch (msghdr.rtm_type)
{
case RTM_NEWADDR:
onNetworkChange(sock, AddressAdded);
break;
case RTM_DELADDR:
onNetworkChange(sock, AddressRemoved);
break;
case RTM_ADD:
case RTM_DELETE:
case RTM_REDIRECT:
onNetworkChange(sock, AvailabilityChanged);
return;
default:
break;
}
}
}
#else
void SystemNative_ReadEvents(int32_t sock, NetworkChangeEvent onNetworkChange)
{
(void)sock;
(void)onNetworkChange;
// unreachable
abort();
}
#endif
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