From 798bfb5e984845a27874d1a244686db6e384d7b8 Mon Sep 17 00:00:00 2001
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From: Nate Karstens <nate.karstens@garmin.com>
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Date: Thu, 13 Jul 2017 09:00:00 -0500
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Subject: [PATCH 04/11] Use list for changed interfaces
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Uses a linked list to store the index of changed network interfaces
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instead of a bitfield. This allows for network interfaces with an
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index greater than 31 (an index of 36 was seen on Android).
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Upstream-Status: Submitted [dts@apple.com]
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Signed-off-by: Nate Karstens <nate.karstens@garmin.com>
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---
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mDNSPosix/mDNSPosix.c | 67 +++++++++++++++++++++++++++++++++----------
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1 file changed, 52 insertions(+), 15 deletions(-)
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diff --git a/mDNSPosix/mDNSPosix.c b/mDNSPosix/mDNSPosix.c
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index 195d04b..bb883c1 100755
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--- a/mDNSPosix/mDNSPosix.c
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+++ b/mDNSPosix/mDNSPosix.c
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@@ -67,6 +67,14 @@ struct IfChangeRec
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};
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typedef struct IfChangeRec IfChangeRec;
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+// Used to build a list of network interface indices
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+struct NetworkInterfaceIndex
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+{
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+ int if_index;
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+ struct NetworkInterfaceIndex *Next;
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+};
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+typedef struct NetworkInterfaceIndex NetworkInterfaceIndex;
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+
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// Note that static data is initialized to zero in (modern) C.
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static PosixEventSource *gEventSources; // linked list of PosixEventSource's
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static sigset_t gEventSignalSet; // Signals which event loop listens for
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@@ -1458,6 +1466,32 @@ mDNSlocal mStatus OpenIfNotifySocket(int *pFD)
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return err;
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}
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+mDNSlocal mDNSBool ListContainsInterfaceIndex(GenLinkedList *list, int if_index)
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+{
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+ NetworkInterfaceIndex *item;
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+
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+ for (item = (NetworkInterfaceIndex*)list->Head; item != NULL; item = item->Next)
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+ {
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+ if (if_index == item->if_index) return mDNStrue;
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+ }
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+
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+ return mDNSfalse;
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+}
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+
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+mDNSlocal void AddInterfaceIndexToList(GenLinkedList *list, int if_index)
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+{
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+ NetworkInterfaceIndex *item;
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+
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+ if (ListContainsInterfaceIndex(list, if_index)) return;
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+
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+ item = malloc(sizeof *item);
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+ if (item == NULL) return;
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+
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+ item->if_index = if_index;
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+ item->Next = NULL;
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+ AddToTail(list, item);
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+}
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+
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#if MDNS_DEBUGMSGS
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mDNSlocal void PrintNetLinkMsg(const struct nlmsghdr *pNLMsg)
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{
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@@ -1485,14 +1519,13 @@ mDNSlocal void PrintNetLinkMsg(const struct nlmsghdr *pNLMsg)
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}
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#endif
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-mDNSlocal mDNSu32 ProcessRoutingNotification(int sd)
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+mDNSlocal void ProcessRoutingNotification(int sd, GenLinkedList *changedInterfaces)
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// Read through the messages on sd and if any indicate that any interface records should
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// be torn down and rebuilt, return affected indices as a bitmask. Otherwise return 0.
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{
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ssize_t readCount;
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char buff[4096];
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struct nlmsghdr *pNLMsg = (struct nlmsghdr*) buff;
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- mDNSu32 result = 0;
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// The structure here is more complex than it really ought to be because,
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// unfortunately, there's no good way to size a buffer in advance large
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@@ -1528,9 +1561,9 @@ mDNSlocal mDNSu32 ProcessRoutingNotification(int sd)
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// Process the NetLink message
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if (pNLMsg->nlmsg_type == RTM_GETLINK || pNLMsg->nlmsg_type == RTM_NEWLINK)
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- result |= 1 << ((struct ifinfomsg*) NLMSG_DATA(pNLMsg))->ifi_index;
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+ AddInterfaceIndexToList(changedInterfaces, ((struct ifinfomsg*) NLMSG_DATA(pNLMsg))->ifi_index);
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else if (pNLMsg->nlmsg_type == RTM_DELADDR || pNLMsg->nlmsg_type == RTM_NEWADDR)
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- result |= 1 << ((struct ifaddrmsg*) NLMSG_DATA(pNLMsg))->ifa_index;
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+ AddInterfaceIndexToList(changedInterfaces, ((struct ifaddrmsg*) NLMSG_DATA(pNLMsg))->ifa_index);
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// Advance pNLMsg to the next message in the buffer
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if ((pNLMsg->nlmsg_flags & NLM_F_MULTI) != 0 && pNLMsg->nlmsg_type != NLMSG_DONE)
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@@ -1541,8 +1574,6 @@ mDNSlocal mDNSu32 ProcessRoutingNotification(int sd)
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else
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break; // all done!
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}
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-
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- return result;
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}
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#else // USES_NETLINK
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@@ -1574,14 +1605,13 @@ mDNSlocal void PrintRoutingSocketMsg(const struct ifa_msghdr *pRSMsg)
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}
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#endif
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-mDNSlocal mDNSu32 ProcessRoutingNotification(int sd)
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+mDNSlocal void ProcessRoutingNotification(int sd, GenLinkedList *changedInterfaces)
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// Read through the messages on sd and if any indicate that any interface records should
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// be torn down and rebuilt, return affected indices as a bitmask. Otherwise return 0.
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{
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ssize_t readCount;
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char buff[4096];
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struct ifa_msghdr *pRSMsg = (struct ifa_msghdr*) buff;
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- mDNSu32 result = 0;
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readCount = read(sd, buff, sizeof buff);
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if (readCount < (ssize_t) sizeof(struct ifa_msghdr))
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@@ -1596,12 +1626,10 @@ mDNSlocal mDNSu32 ProcessRoutingNotification(int sd)
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pRSMsg->ifam_type == RTM_IFINFO)
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{
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if (pRSMsg->ifam_type == RTM_IFINFO)
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- result |= 1 << ((struct if_msghdr*) pRSMsg)->ifm_index;
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+ AddInterfaceIndexToList(changedInterfaces, ((struct if_msghdr*) pRSMsg)->ifm_index);
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else
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- result |= 1 << pRSMsg->ifam_index;
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+ AddInterfaceIndexToList(changedInterfaces, pRSMsg->ifam_index);
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}
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-
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- return result;
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}
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#endif // USES_NETLINK
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@@ -1611,7 +1639,8 @@ mDNSlocal void InterfaceChangeCallback(int fd, void *context)
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{
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IfChangeRec *pChgRec = (IfChangeRec*) context;
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fd_set readFDs;
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- mDNSu32 changedInterfaces = 0;
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+ GenLinkedList changedInterfaces;
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+ NetworkInterfaceIndex *changedInterface;
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struct timeval zeroTimeout = { 0, 0 };
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(void)fd; // Unused
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@@ -1619,17 +1648,25 @@ mDNSlocal void InterfaceChangeCallback(int fd, void *context)
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FD_ZERO(&readFDs);
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FD_SET(pChgRec->NotifySD, &readFDs);
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+ InitLinkedList(&changedInterfaces, offsetof(NetworkInterfaceIndex, Next));
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+
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do
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{
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- changedInterfaces |= ProcessRoutingNotification(pChgRec->NotifySD);
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+ ProcessRoutingNotification(pChgRec->NotifySD, &changedInterfaces);
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}
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while (0 < select(pChgRec->NotifySD + 1, &readFDs, (fd_set*) NULL, (fd_set*) NULL, &zeroTimeout));
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// Currently we rebuild the entire interface list whenever any interface change is
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// detected. If this ever proves to be a performance issue in a multi-homed
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// configuration, more care should be paid to changedInterfaces.
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- if (changedInterfaces)
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+ if (changedInterfaces.Head != NULL)
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mDNSPlatformPosixRefreshInterfaceList(pChgRec->mDNS);
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+
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+ while ((changedInterface = (NetworkInterfaceIndex*)changedInterfaces.Head) != NULL)
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+ {
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+ RemoveFromList(&changedInterfaces, changedInterface);
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+ free(changedInterface);
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+ }
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}
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// Register with either a Routing Socket or RtNetLink to listen for interface changes.
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--
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2.20.1
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