Support parsing netlink route messages. (d7ff7ea6) · Commits · e / os / android_system_core

include/sysutils/NetlinkEvent.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -37,6 +37,8 @@ public:
		const static int NlActionAddressUpdated;
		const static int NlActionAddressRemoved;
		const static int NlActionRdnss;
		const static int NlActionRouteUpdated;
		const static int NlActionRouteRemoved;

		NetlinkEvent();
		virtual ~NetlinkEvent();
		@@ -55,6 +57,7 @@ public:
		bool parseIfInfoMessage(const struct nlmsghdr *nh);
		bool parseIfAddrMessage(const struct nlmsghdr *nh);
		bool parseUlogPacketMessage(const struct nlmsghdr *nh);
		bool parseRtMessage(const struct nlmsghdr *nh);
		bool parseNdUserOptMessage(const struct nlmsghdr *nh);
		};

libsysutils/src/NetlinkEvent.cpp

+99 −0

Original line number	Diff line number	Diff line
		@@ -48,6 +48,8 @@ const int NetlinkEvent::NlActionLinkDown = 5;
		const int NetlinkEvent::NlActionAddressUpdated = 6;
		const int NetlinkEvent::NlActionAddressRemoved = 7;
		const int NetlinkEvent::NlActionRdnss = 8;
		const int NetlinkEvent::NlActionRouteUpdated = 9;
		const int NetlinkEvent::NlActionRouteRemoved = 10;

		NetlinkEvent::NetlinkEvent() {
		mAction = NlActionUnknown;
		@@ -269,6 +271,98 @@ bool NetlinkEvent::parseUlogPacketMessage(const struct nlmsghdr *nh) {
		return true;
		}

		/*
		* Parse a RTM_NEWROUTE or RTM_DELROUTE message.
		*/
		bool NetlinkEvent::parseRtMessage(const struct nlmsghdr *nh) {
		uint8_t type = nh->nlmsg_type;
		const char *msgname = rtMessageName(type);

		// Sanity check.
		if (type != RTM_NEWROUTE && type != RTM_DELROUTE) {
		SLOGE("%s: incorrect message type %d (%s)\n", __func__, type, msgname);
		return false;
		}

		struct rtmsg rtm = (struct rtmsg ) NLMSG_DATA(nh);
		if (!checkRtNetlinkLength(nh, sizeof(*rtm)))
		return false;

		if (// Ignore static routes we've set up ourselves.
		(rtm->rtm_protocol != RTPROT_KERNEL &&
		rtm->rtm_protocol != RTPROT_RA) \|\|
		// We're only interested in global unicast routes.
		(rtm->rtm_scope != RT_SCOPE_UNIVERSE) \|\|
		(rtm->rtm_type != RTN_UNICAST) \|\|
		// We don't support source routing.
		(rtm->rtm_src_len != 0) \|\|
		// Cloned routes aren't real routes.
		(rtm->rtm_flags & RTM_F_CLONED)) {
		return false;
		}

		int family = rtm->rtm_family;
		int prefixLength = rtm->rtm_dst_len;

		// Currently we only support: destination, (one) next hop, ifindex.
		char dst[INET6_ADDRSTRLEN] = "";
		char gw[INET6_ADDRSTRLEN] = "";
		char dev[IFNAMSIZ] = "";

		size_t len = RTM_PAYLOAD(nh);
		struct rtattr *rta;
		for (rta = RTM_RTA(rtm); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
		switch (rta->rta_type) {
		case RTA_DST:
		if (maybeLogDuplicateAttribute(*dst, "RTA_DST", msgname))
		continue;
		if (!inet_ntop(family, RTA_DATA(rta), dst, sizeof(dst)))
		return false;
		continue;
		case RTA_GATEWAY:
		if (maybeLogDuplicateAttribute(*gw, "RTA_GATEWAY", msgname))
		continue;
		if (!inet_ntop(family, RTA_DATA(rta), gw, sizeof(gw)))
		return false;
		continue;
		case RTA_OIF:
		if (maybeLogDuplicateAttribute(*dev, "RTA_OIF", msgname))
		continue;
		if (!if_indextoname(* (int *) RTA_DATA(rta), dev))
		return false;
		default:
		continue;
		}
		}

		// If there's no RTA_DST attribute, then:
		// - If the prefix length is zero, it's the default route.
		// - If the prefix length is nonzero, there's something we don't understand.
		// Ignore the event.
		if (!*dst && !prefixLength) {
		if (family == AF_INET) {
		strncpy(dst, "0.0.0.0", sizeof(dst));
		} else if (family == AF_INET6) {
		strncpy(dst, "::", sizeof(dst));
		}
		}

		// A useful route must have a destination and at least either a gateway or
		// an interface.
		if (!dst \|\| (!gw && !*dev))
		return false;

		// Fill in netlink event information.
		mAction = (type == RTM_NEWROUTE) ? NlActionRouteUpdated :
		NlActionRouteRemoved;
		mSubsystem = strdup("net");
		asprintf(&mParams[0], "ROUTE=%s/%d", dst, prefixLength);
		asprintf(&mParams[1], "GATEWAY=%s", (*gw) ? gw : "");
		asprintf(&mParams[2], "INTERFACE=%s", (*dev) ? dev : "");

		return true;
		}

		/*
		* Parse a RTM_NEWNDUSEROPT message.
		*/
		@@ -408,6 +502,11 @@ bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
		if (parseIfAddrMessage(nh))
		return true;

		} else if (nh->nlmsg_type == RTM_NEWROUTE \|\|
		nh->nlmsg_type == RTM_DELROUTE) {
		if (parseRtMessage(nh))
		return true;

		} else if (nh->nlmsg_type == RTM_NEWNDUSEROPT) {
		if (parseNdUserOptMessage(nh))
		return true;