Merge "Improvements to netlink event parsing."
diff --git a/include/sysutils/NetlinkEvent.h b/include/sysutils/NetlinkEvent.h
index c0a9418..a247a74 100644
--- a/include/sysutils/NetlinkEvent.h
+++ b/include/sysutils/NetlinkEvent.h
@@ -52,8 +52,10 @@
protected:
bool parseBinaryNetlinkMessage(char *buffer, int size);
bool parseAsciiNetlinkMessage(char *buffer, int size);
- bool parseIfAddrMessage(int type, struct ifaddrmsg *ifaddr, int rtasize);
- bool parseNdUserOptMessage(struct nduseroptmsg *msg, int optsize);
+ bool parseIfInfoMessage(const struct nlmsghdr *nh);
+ bool parseIfAddrMessage(const struct nlmsghdr *nh);
+ bool parseUlogPacketMessage(const struct nlmsghdr *nh);
+ bool parseNdUserOptMessage(const struct nlmsghdr *nh);
};
#endif
diff --git a/libsysutils/src/NetlinkEvent.cpp b/libsysutils/src/NetlinkEvent.cpp
index 1c9c70a..41bd215 100644
--- a/libsysutils/src/NetlinkEvent.cpp
+++ b/libsysutils/src/NetlinkEvent.cpp
@@ -29,6 +29,8 @@
#include <net/if.h>
#include <linux/if.h>
+#include <linux/if_addr.h>
+#include <linux/if_link.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter_ipv4/ipt_ULOG.h>
/* From kernel's net/netfilter/xt_quota2.c */
@@ -78,32 +80,109 @@
}
/*
+ * Returns the message name for a message in the NETLINK_ROUTE family, or NULL
+ * if parsing that message is not supported.
+ */
+static const char *rtMessageName(int type) {
+#define NL_EVENT_RTM_NAME(rtm) case rtm: return #rtm;
+ switch (type) {
+ NL_EVENT_RTM_NAME(RTM_NEWLINK);
+ NL_EVENT_RTM_NAME(RTM_DELLINK);
+ NL_EVENT_RTM_NAME(RTM_NEWADDR);
+ NL_EVENT_RTM_NAME(RTM_DELADDR);
+ NL_EVENT_RTM_NAME(RTM_NEWROUTE);
+ NL_EVENT_RTM_NAME(RTM_DELROUTE);
+ NL_EVENT_RTM_NAME(RTM_NEWNDUSEROPT);
+ NL_EVENT_RTM_NAME(QLOG_NL_EVENT);
+ default:
+ return NULL;
+ }
+#undef NL_EVENT_RTM_NAME
+}
+
+/*
+ * Checks that a binary NETLINK_ROUTE message is long enough for a payload of
+ * size bytes.
+ */
+static bool checkRtNetlinkLength(const struct nlmsghdr *nh, size_t size) {
+ if (nh->nlmsg_len < NLMSG_LENGTH(size)) {
+ SLOGE("Got a short %s message\n", rtMessageName(nh->nlmsg_type));
+ return false;
+ }
+ return true;
+}
+
+/*
+ * Utility function to log errors.
+ */
+static bool maybeLogDuplicateAttribute(bool isDup,
+ const char *attributeName,
+ const char *messageName) {
+ if (isDup) {
+ SLOGE("Multiple %s attributes in %s, ignoring\n", attributeName, messageName);
+ return true;
+ }
+ return false;
+}
+
+/*
+ * Parse a RTM_NEWLINK message.
+ */
+bool NetlinkEvent::parseIfInfoMessage(const struct nlmsghdr *nh) {
+ struct ifinfomsg *ifi = (struct ifinfomsg *) NLMSG_DATA(nh);
+ if (!checkRtNetlinkLength(nh, sizeof(*ifi)))
+ return false;
+
+ if ((ifi->ifi_flags & IFF_LOOPBACK) != 0) {
+ return false;
+ }
+
+ int len = IFLA_PAYLOAD(nh);
+ struct rtattr *rta;
+ for (rta = IFLA_RTA(ifi); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
+ switch(rta->rta_type) {
+ case IFLA_IFNAME:
+ asprintf(&mParams[0], "INTERFACE=%s", (char *) RTA_DATA(rta));
+ mAction = (ifi->ifi_flags & IFF_LOWER_UP) ? NlActionLinkUp :
+ NlActionLinkDown;
+ mSubsystem = strdup("net");
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/*
* Parse a RTM_NEWADDR or RTM_DELADDR message.
*/
-bool NetlinkEvent::parseIfAddrMessage(int type, struct ifaddrmsg *ifaddr,
- int rtasize) {
- struct rtattr *rta;
+bool NetlinkEvent::parseIfAddrMessage(const struct nlmsghdr *nh) {
+ struct ifaddrmsg *ifaddr = (struct ifaddrmsg *) NLMSG_DATA(nh);
struct ifa_cacheinfo *cacheinfo = NULL;
char addrstr[INET6_ADDRSTRLEN] = "";
+ char ifname[IFNAMSIZ];
+
+ if (!checkRtNetlinkLength(nh, sizeof(*ifaddr)))
+ return false;
// Sanity check.
+ int type = nh->nlmsg_type;
if (type != RTM_NEWADDR && type != RTM_DELADDR) {
SLOGE("parseIfAddrMessage on incorrect message type 0x%x\n", type);
return false;
}
// For log messages.
- const char *msgtype = (type == RTM_NEWADDR) ? "RTM_NEWADDR" : "RTM_DELADDR";
+ const char *msgtype = rtMessageName(type);
- for (rta = IFA_RTA(ifaddr); RTA_OK(rta, rtasize);
- rta = RTA_NEXT(rta, rtasize)) {
+ struct rtattr *rta;
+ int len = IFA_PAYLOAD(nh);
+ for (rta = IFA_RTA(ifaddr); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
if (rta->rta_type == IFA_ADDRESS) {
// Only look at the first address, because we only support notifying
// one change at a time.
- if (*addrstr != '\0') {
- SLOGE("Multiple IFA_ADDRESSes in %s, ignoring\n", msgtype);
+ if (maybeLogDuplicateAttribute(*addrstr != '\0', "IFA_ADDRESS", msgtype))
continue;
- }
// Convert the IP address to a string.
if (ifaddr->ifa_family == AF_INET) {
@@ -128,28 +207,15 @@
}
// Find the interface name.
- char ifname[IFNAMSIZ + 1];
if (!if_indextoname(ifaddr->ifa_index, ifname)) {
SLOGE("Unknown ifindex %d in %s", ifaddr->ifa_index, msgtype);
return false;
}
- // Fill in interface information.
- mAction = (type == RTM_NEWADDR) ? NlActionAddressUpdated :
- NlActionAddressRemoved;
- mSubsystem = strdup("net");
- asprintf(&mParams[0], "ADDRESS=%s/%d", addrstr,
- ifaddr->ifa_prefixlen);
- asprintf(&mParams[1], "INTERFACE=%s", ifname);
- asprintf(&mParams[2], "FLAGS=%u", ifaddr->ifa_flags);
- asprintf(&mParams[3], "SCOPE=%u", ifaddr->ifa_scope);
} else if (rta->rta_type == IFA_CACHEINFO) {
// Address lifetime information.
- if (cacheinfo) {
- // We only support one address.
- SLOGE("Multiple IFA_CACHEINFOs in %s, ignoring\n", msgtype);
+ if (maybeLogDuplicateAttribute(cacheinfo, "IFA_CACHEINFO", msgtype))
continue;
- }
if (RTA_PAYLOAD(rta) < sizeof(*cacheinfo)) {
SLOGE("Short IFA_CACHEINFO (%zu vs. %zu bytes) in %s",
@@ -158,10 +224,6 @@
}
cacheinfo = (struct ifa_cacheinfo *) RTA_DATA(rta);
- asprintf(&mParams[4], "PREFERRED=%u", cacheinfo->ifa_prefered);
- asprintf(&mParams[5], "VALID=%u", cacheinfo->ifa_valid);
- asprintf(&mParams[6], "CSTAMP=%u", cacheinfo->cstamp);
- asprintf(&mParams[7], "TSTAMP=%u", cacheinfo->tstamp);
}
}
@@ -170,14 +232,53 @@
return false;
}
+ // Fill in netlink event information.
+ mAction = (type == RTM_NEWADDR) ? NlActionAddressUpdated :
+ NlActionAddressRemoved;
+ mSubsystem = strdup("net");
+ asprintf(&mParams[0], "ADDRESS=%s/%d", addrstr,
+ ifaddr->ifa_prefixlen);
+ asprintf(&mParams[1], "INTERFACE=%s", ifname);
+ asprintf(&mParams[2], "FLAGS=%u", ifaddr->ifa_flags);
+ asprintf(&mParams[3], "SCOPE=%u", ifaddr->ifa_scope);
+
+ if (cacheinfo) {
+ asprintf(&mParams[4], "PREFERRED=%u", cacheinfo->ifa_prefered);
+ asprintf(&mParams[5], "VALID=%u", cacheinfo->ifa_valid);
+ asprintf(&mParams[6], "CSTAMP=%u", cacheinfo->cstamp);
+ asprintf(&mParams[7], "TSTAMP=%u", cacheinfo->tstamp);
+ }
+
+ return true;
+}
+
+/*
+ * Parse a QLOG_NL_EVENT message.
+ */
+bool NetlinkEvent::parseUlogPacketMessage(const struct nlmsghdr *nh) {
+ const char *devname;
+ ulog_packet_msg_t *pm = (ulog_packet_msg_t *) NLMSG_DATA(nh);
+ if (!checkRtNetlinkLength(nh, sizeof(*pm)))
+ return false;
+
+ devname = pm->indev_name[0] ? pm->indev_name : pm->outdev_name;
+ asprintf(&mParams[0], "ALERT_NAME=%s", pm->prefix);
+ asprintf(&mParams[1], "INTERFACE=%s", devname);
+ mSubsystem = strdup("qlog");
+ mAction = NlActionChange;
return true;
}
/*
* Parse a RTM_NEWNDUSEROPT message.
*/
-bool NetlinkEvent::parseNdUserOptMessage(struct nduseroptmsg *msg, int len) {
+bool NetlinkEvent::parseNdUserOptMessage(const struct nlmsghdr *nh) {
+ struct nduseroptmsg *msg = (struct nduseroptmsg *) NLMSG_DATA(nh);
+ if (!checkRtNetlinkLength(nh, sizeof(*msg)))
+ return false;
+
// Check the length is valid.
+ int len = NLMSG_PAYLOAD(nh, sizeof(*msg));
if (msg->nduseropt_opts_len > len) {
SLOGE("RTM_NEWNDUSEROPT invalid length %d > %d\n",
msg->nduseropt_opts_len, len);
@@ -200,7 +301,7 @@
}
// Find the interface name.
- char ifname[IFNAMSIZ + 1];
+ char ifname[IFNAMSIZ];
if (!if_indextoname(msg->nduseropt_ifindex, ifname)) {
SLOGE("RTM_NEWNDUSEROPT on unknown ifindex %d\n",
msg->nduseropt_ifindex);
@@ -273,6 +374,14 @@
/*
* Parse a binary message from a NETLINK_ROUTE netlink socket.
+ *
+ * Note that this function can only parse one message, because the message's
+ * content has to be stored in the class's member variables (mAction,
+ * mSubsystem, etc.). Invalid or unrecognized messages are skipped, but if
+ * there are multiple valid messages in the buffer, only the first one will be
+ * returned.
+ *
+ * TODO: consider only ever looking at the first message.
*/
bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
const struct nlmsghdr *nh;
@@ -281,93 +390,32 @@
NLMSG_OK(nh, (unsigned) size) && (nh->nlmsg_type != NLMSG_DONE);
nh = NLMSG_NEXT(nh, size)) {
+ if (!rtMessageName(nh->nlmsg_type)) {
+ SLOGD("Unexpected netlink message type %d\n", nh->nlmsg_type);
+ continue;
+ }
+
if (nh->nlmsg_type == RTM_NEWLINK) {
- int len = nh->nlmsg_len - sizeof(*nh);
- struct ifinfomsg *ifi;
-
- if (sizeof(*ifi) > (size_t) len) {
- SLOGE("Got a short RTM_NEWLINK message\n");
- continue;
- }
-
- ifi = (ifinfomsg *)NLMSG_DATA(nh);
- if ((ifi->ifi_flags & IFF_LOOPBACK) != 0) {
- continue;
- }
-
- struct rtattr *rta = (struct rtattr *)
- ((char *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
- len = NLMSG_PAYLOAD(nh, sizeof(*ifi));
-
- while(RTA_OK(rta, len)) {
- switch(rta->rta_type) {
- case IFLA_IFNAME:
- char buffer[16 + IFNAMSIZ];
- snprintf(buffer, sizeof(buffer), "INTERFACE=%s",
- (char *) RTA_DATA(rta));
- mParams[0] = strdup(buffer);
- mAction = (ifi->ifi_flags & IFF_LOWER_UP) ?
- NlActionLinkUp : NlActionLinkDown;
- mSubsystem = strdup("net");
- break;
- }
-
- rta = RTA_NEXT(rta, len);
- }
+ if (parseIfInfoMessage(nh))
+ return true;
} else if (nh->nlmsg_type == QLOG_NL_EVENT) {
- char *devname;
- ulog_packet_msg_t *pm;
- size_t len = nh->nlmsg_len - sizeof(*nh);
- if (sizeof(*pm) > len) {
- SLOGE("Got a short QLOG message\n");
- continue;
- }
- pm = (ulog_packet_msg_t *)NLMSG_DATA(nh);
- devname = pm->indev_name[0] ? pm->indev_name : pm->outdev_name;
- asprintf(&mParams[0], "ALERT_NAME=%s", pm->prefix);
- asprintf(&mParams[1], "INTERFACE=%s", devname);
- mSubsystem = strdup("qlog");
- mAction = NlActionChange;
+ if (parseUlogPacketMessage(nh))
+ return true;
} else if (nh->nlmsg_type == RTM_NEWADDR ||
nh->nlmsg_type == RTM_DELADDR) {
- int len = nh->nlmsg_len - sizeof(*nh);
- struct ifaddrmsg *ifa;
-
- if (sizeof(*ifa) > (size_t) len) {
- SLOGE("Got a short RTM_xxxADDR message\n");
- continue;
- }
-
- ifa = (ifaddrmsg *)NLMSG_DATA(nh);
- size_t rtasize = IFA_PAYLOAD(nh);
- if (!parseIfAddrMessage(nh->nlmsg_type, ifa, rtasize)) {
- continue;
- }
+ if (parseIfAddrMessage(nh))
+ return true;
} else if (nh->nlmsg_type == RTM_NEWNDUSEROPT) {
- int len = nh->nlmsg_len - sizeof(*nh);
- struct nduseroptmsg *ndmsg = (struct nduseroptmsg *) NLMSG_DATA(nh);
+ if (parseNdUserOptMessage(nh))
+ return true;
- if (sizeof(*ndmsg) > (size_t) len) {
- SLOGE("Got a short RTM_NEWNDUSEROPT message\n");
- continue;
- }
-
- size_t optsize = NLMSG_PAYLOAD(nh, sizeof(*ndmsg));
- if (!parseNdUserOptMessage(ndmsg, optsize)) {
- continue;
- }
-
-
- } else {
- SLOGD("Unexpected netlink message. type=0x%x\n",
- nh->nlmsg_type);
}
}
- return true;
+ return false;
}
/* If the string between 'str' and 'end' begins with 'prefixlen' characters
diff --git a/libsysutils/src/NetlinkListener.cpp b/libsysutils/src/NetlinkListener.cpp
index 9c447ca..81c5cc2 100644
--- a/libsysutils/src/NetlinkListener.cpp
+++ b/libsysutils/src/NetlinkListener.cpp
@@ -57,10 +57,12 @@
}
NetlinkEvent *evt = new NetlinkEvent();
- if (!evt->decode(mBuffer, count, mFormat)) {
- SLOGE("Error decoding NetlinkEvent");
- } else {
+ if (evt->decode(mBuffer, count, mFormat)) {
onEvent(evt);
+ } else if (mFormat != NETLINK_FORMAT_BINARY) {
+ // Don't complain if parseBinaryNetlinkMessage returns false. That can
+ // just mean that the buffer contained no messages we're interested in.
+ SLOGE("Error decoding NetlinkEvent");
}
delete evt;