| From bfa1d68bed863e22c40a6d9a19ffbcc8694bbff6 Mon Sep 17 00:00:00 2001 |
| From: Nate Karstens <nate.karstens@garmin.com> |
| Date: Mon, 24 Jul 2017 09:38:55 -0500 |
| Subject: [PATCH 6/8] Handle noisy netlink sockets |
| |
| The POSIX implementation currently clears all network interfaces |
| when netlink indicates that there has been a change. This causes |
| the following problems: |
| |
| 1) Applications are informed that all of the services they are |
| tracking have been removed. |
| 2) Increases network load because the client must re-query for |
| all records it is interested in. |
| |
| This changes netlink notification handling by: |
| |
| 1) Always comparing with the latest interface list returned |
| by the OS. |
| 2) Confirming that the interface has been changed in a way |
| that we care about. |
| |
| Upstream-Status: Submitted [dts@apple.com] |
| |
| Signed-off-by: Nate Karstens <nate.karstens@garmin.com> |
| Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com> |
| --- |
| mDNSPosix/mDNSPosix.c | 182 +++++++++++++++++++++++++++++++++++++++--- |
| 1 file changed, 172 insertions(+), 10 deletions(-) |
| |
| diff --git a/mDNSPosix/mDNSPosix.c b/mDNSPosix/mDNSPosix.c |
| index e20adda92229..5d52de31f79b 100644 |
| --- a/mDNSPosix/mDNSPosix.c |
| +++ b/mDNSPosix/mDNSPosix.c |
| @@ -1788,14 +1788,43 @@ mDNSlocal void ProcessRoutingNotification(int sd, GenLinkedList *change |
| |
| #endif // USES_NETLINK |
| |
| +// Test whether the given PosixNetworkInterface matches the given struct ifaddrs |
| +mDNSlocal mDNSBool InterfacesMatch(PosixNetworkInterface *intf, struct ifaddrs *ifi) |
| +{ |
| + mDNSBool match = mDNSfalse; |
| + mDNSAddr ip, mask; |
| + unsigned int if_index; |
| + |
| + if_index = if_nametoindex(ifi->ifa_name); |
| + if (if_index == 0) |
| + return mDNSfalse; |
| + |
| + if((intf->index == if_index) && |
| + (intf->sa_family == ifi->ifa_addr->sa_family) && |
| + (strcmp(intf->coreIntf.ifname, ifi->ifa_name) == 0)) |
| + { |
| + SockAddrTomDNSAddr(ifi->ifa_addr, &ip, NULL); |
| + SockAddrTomDNSAddr(ifi->ifa_netmask, &mask, NULL); |
| + |
| + match = mDNSSameAddress(&intf->coreIntf.ip, &ip) && |
| + mDNSSameAddress(&intf->coreIntf.mask, &mask); |
| + } |
| + |
| + return match; |
| +} |
| + |
| // Called when data appears on interface change notification socket |
| mDNSlocal void InterfaceChangeCallback(int fd, void *context) |
| { |
| IfChangeRec *pChgRec = (IfChangeRec*) context; |
| + mDNS *m = pChgRec->mDNS; |
| fd_set readFDs; |
| GenLinkedList changedInterfaces; |
| NetworkInterfaceIndex *changedInterface; |
| struct timeval zeroTimeout = { 0, 0 }; |
| + struct ifaddrs *ifa_list, **ifi, *ifa_loop4 = NULL; |
| + PosixNetworkInterface *intf, *intfNext; |
| + mDNSBool found, foundav4; |
| |
| (void)fd; // Unused |
| |
| @@ -1810,12 +1839,149 @@ mDNSlocal void InterfaceChangeCallback(int fd, void *context) |
| } |
| while (0 < select(pChgRec->NotifySD + 1, &readFDs, (fd_set*) NULL, (fd_set*) NULL, &zeroTimeout)); |
| |
| - // Currently we rebuild the entire interface list whenever any interface change is |
| - // detected. If this ever proves to be a performance issue in a multi-homed |
| - // configuration, more care should be paid to changedInterfaces. |
| - if (changedInterfaces.Head != NULL) |
| - mDNSPlatformPosixRefreshInterfaceList(pChgRec->mDNS); |
| + CleanRecentInterfaces(); |
| + |
| + if (changedInterfaces.Head == NULL) goto cleanup; |
| + |
| + if (getifaddrs(&ifa_list) < 0) goto cleanup; |
| + |
| + for (intf = (PosixNetworkInterface*)(m->HostInterfaces); intf != NULL; intf = intfNext) |
| + { |
| + intfNext = (PosixNetworkInterface*)(intf->coreIntf.next); |
| + |
| + // Loopback interface(s) are handled later |
| + if (intf->coreIntf.Loopback) continue; |
| + |
| + found = mDNSfalse; |
| + for (ifi = &ifa_list; *ifi != NULL; ifi = &(*ifi)->ifa_next) |
| + { |
| + if (InterfacesMatch(intf, *ifi)) |
| + { |
| + found = mDNStrue; |
| + break; |
| + } |
| + } |
| + |
| + // Removes changed and old interfaces from m->HostInterfaces |
| + if (!found) TearDownInterface(m, intf); |
| + } |
| + |
| + // Add new and changed interfaces in ifa_list |
| + // Save off loopback interface in case it is needed later |
| + for (ifi = &ifa_list; *ifi != NULL; ifi = &(*ifi)->ifa_next) |
| + { |
| + found = mDNSfalse; |
| + for (intf = (PosixNetworkInterface*)(m->HostInterfaces); intf != NULL; intf = intfNext) |
| + { |
| + intfNext = (PosixNetworkInterface*)(intf->coreIntf.next); |
| + |
| + // Loopback interface(s) are handled later |
| + if (intf->coreIntf.Loopback) continue; |
| + |
| + if (InterfacesMatch(intf, *ifi)) |
| + { |
| + found = mDNStrue; |
| + break; |
| + } |
| + |
| + // Removes changed and old interfaces from m->HostInterfaces |
| + } |
| + if (found) |
| + continue; |
| + |
| + if ((ifa_loop4 == NULL) && |
| + ((*ifi)->ifa_addr->sa_family == AF_INET) && |
| + ((*ifi)->ifa_flags & IFF_UP) && |
| + ((*ifi)->ifa_flags & IFF_LOOPBACK)) |
| + { |
| + ifa_loop4 = *ifi; |
| + continue; |
| + } |
| + |
| + if ( (((*ifi)->ifa_addr->sa_family == AF_INET) |
| +#if HAVE_IPV6 |
| + || ((*ifi)->ifa_addr->sa_family == AF_INET6) |
| +#endif |
| + ) && ((*ifi)->ifa_flags & IFF_UP) |
| + && !((*ifi)->ifa_flags & IFF_POINTOPOINT) |
| + && !((*ifi)->ifa_flags & IFF_LOOPBACK)) |
| + { |
| + struct ifaddrs *i = *ifi; |
| + |
| +#define ethernet_addr_len 6 |
| + uint8_t hwaddr[ethernet_addr_len]; |
| + int hwaddr_len = 0; |
| + |
| +#if defined(TARGET_OS_LINUX) && TARGET_OS_LINUX |
| + struct ifreq ifr; |
| + int sockfd = socket(AF_INET6, SOCK_DGRAM, 0); |
| + if (sockfd >= 0) |
| + { |
| + /* Add hardware address */ |
| + memcpy(ifr.ifr_name, i->ifa_name, IFNAMSIZ); |
| + if (ioctl(sockfd, SIOCGIFHWADDR, &ifr) != -1) |
| + { |
| + if (ifr.ifr_hwaddr.sa_family == ARPHRD_ETHER) |
| + { |
| + memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, ethernet_addr_len); |
| + hwaddr_len = ethernet_addr_len; |
| + } |
| + } |
| + close(sockfd); |
| + } |
| + else |
| + { |
| + memset(hwaddr, 0, sizeof(hwaddr)); |
| + } |
| +#endif // TARGET_OS_LINUX |
| + SetupOneInterface(m, i->ifa_addr, i->ifa_netmask, |
| + hwaddr, hwaddr_len, i->ifa_name, if_nametoindex(i->ifa_name), i->ifa_flags); |
| + } |
| + } |
| + |
| + // Determine if there is at least one non-loopback IPv4 interface. This is to work around issues |
| + // with multicast loopback on IPv6 interfaces -- see corresponding logic in SetupInterfaceList(). |
| + foundav4 = mDNSfalse; |
| + for (intf = (PosixNetworkInterface*)(m->HostInterfaces); intf != NULL; intf = (PosixNetworkInterface*)(intf->coreIntf.next)) |
| + { |
| + if (intf->sa_family == AF_INET && !intf->coreIntf.Loopback) |
| + { |
| + foundav4 = mDNStrue; |
| + break; |
| + } |
| + } |
| + |
| + if (foundav4) |
| + { |
| + for (intf = (PosixNetworkInterface*)(m->HostInterfaces); intf != NULL; intf = intfNext) |
| + { |
| + intfNext = (PosixNetworkInterface*)(intf->coreIntf.next); |
| + if (intf->coreIntf.Loopback) TearDownInterface(m, intf); |
| + } |
| + } |
| + else |
| + { |
| + found = mDNSfalse; |
| + |
| + for (intf = (PosixNetworkInterface*)(m->HostInterfaces); intf != NULL; intf = (PosixNetworkInterface*)(intf->coreIntf.next)) |
| + { |
| + if (intf->coreIntf.Loopback) |
| + { |
| + found = mDNStrue; |
| + break; |
| + } |
| + } |
| + |
| + if (!found && (ifa_loop4 != NULL)) |
| + { |
| + SetupOneInterface(m, ifa_loop4->ifa_addr, ifa_loop4->ifa_netmask, |
| + NULL, 0, ifa_loop4->ifa_name, if_nametoindex(ifa_loop4->ifa_name), ifa_loop4->ifa_flags); |
| + } |
| + } |
| + |
| + if (ifa_list != NULL) freeifaddrs(ifa_list); |
| |
| +cleanup: |
| while ((changedInterface = (NetworkInterfaceIndex*)changedInterfaces.Head) != NULL) |
| { |
| RemoveFromList(&changedInterfaces, changedInterface); |
| @@ -1947,15 +2113,11 @@ mDNSexport void mDNSPlatformClose(mDNS *const m) |
| #endif |
| } |
| |
| -// This is used internally by InterfaceChangeCallback. |
| -// It's also exported so that the Standalone Responder (mDNSResponderPosix) |
| +// This is exported so that the Standalone Responder (mDNSResponderPosix) |
| // can call it in response to a SIGHUP (mainly for debugging purposes). |
| mDNSexport mStatus mDNSPlatformPosixRefreshInterfaceList(mDNS *const m) |
| { |
| int err; |
| - // This is a pretty heavyweight way to process interface changes -- |
| - // destroying the entire interface list and then making fresh one from scratch. |
| - // We should make it like the OS X version, which leaves unchanged interfaces alone. |
| ClearInterfaceList(m); |
| err = SetupInterfaceList(m); |
| return PosixErrorToStatus(err); |
| -- |
| 2.35.1 |
| |