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platform_system_core/libsysutils/src/NetlinkEvent.cpp

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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdlib.h>
#include <string.h>
#define LOG_TAG "NetlinkEvent"
#include <cutils/log.h>
#include <sysutils/NetlinkEvent.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <linux/if.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter_ipv4/ipt_ULOG.h>
/* From kernel's net/netfilter/xt_quota2.c */
const int QLOG_NL_EVENT = 112;
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
const int NetlinkEvent::NlActionUnknown = 0;
const int NetlinkEvent::NlActionAdd = 1;
const int NetlinkEvent::NlActionRemove = 2;
const int NetlinkEvent::NlActionChange = 3;
const int NetlinkEvent::NlActionLinkUp = 4;
const int NetlinkEvent::NlActionLinkDown = 5;
NetlinkEvent::NetlinkEvent() {
mAction = NlActionUnknown;
memset(mParams, 0, sizeof(mParams));
mPath = NULL;
mSubsystem = NULL;
}
NetlinkEvent::~NetlinkEvent() {
int i;
if (mPath)
free(mPath);
if (mSubsystem)
free(mSubsystem);
for (i = 0; i < NL_PARAMS_MAX; i++) {
if (!mParams[i])
break;
free(mParams[i]);
}
}
void NetlinkEvent::dump() {
int i;
for (i = 0; i < NL_PARAMS_MAX; i++) {
if (!mParams[i])
break;
SLOGD("NL param '%s'\n", mParams[i]);
}
}
/*
* Decode a RTM_NEWADDR or RTM_DELADDR message.
*/
bool NetlinkEvent::parseIfAddrMessage(int type, struct ifaddrmsg *ifaddr,
int rtasize) {
struct rtattr *rta;
struct ifa_cacheinfo *cacheinfo = NULL;
char addrstr[INET6_ADDRSTRLEN] = "";
// Sanity check.
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";
for (rta = IFA_RTA(ifaddr); RTA_OK(rta, rtasize);
rta = RTA_NEXT(rta, rtasize)) {
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);
continue;
}
// Convert the IP address to a string.
if (ifaddr->ifa_family == AF_INET) {
struct in_addr *addr4 = (struct in_addr *) RTA_DATA(rta);
if (RTA_PAYLOAD(rta) < sizeof(*addr4)) {
SLOGE("Short IPv4 address (%d bytes) in %s",
RTA_PAYLOAD(rta), msgtype);
continue;
}
inet_ntop(AF_INET, addr4, addrstr, sizeof(addrstr));
} else if (ifaddr->ifa_family == AF_INET6) {
struct in6_addr *addr6 = (struct in6_addr *) RTA_DATA(rta);
if (RTA_PAYLOAD(rta) < sizeof(*addr6)) {
SLOGE("Short IPv6 address (%d bytes) in %s",
RTA_PAYLOAD(rta), msgtype);
continue;
}
inet_ntop(AF_INET6, addr6, addrstr, sizeof(addrstr));
} else {
SLOGE("Unknown address family %d\n", ifaddr->ifa_family);
continue;
}
// 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) ? NlActionAdd : NlActionRemove;
mSubsystem = strdup("address");
asprintf(&mParams[0], "ADDRESS=%s/%d", addrstr,
ifaddr->ifa_prefixlen);
asprintf(&mParams[1], "IFACE=%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);
continue;
}
if (RTA_PAYLOAD(rta) < sizeof(*cacheinfo)) {
SLOGE("Short IFA_CACHEINFO (%d vs. %d bytes) in %s",
RTA_PAYLOAD(rta), sizeof(cacheinfo), msgtype);
continue;
}
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);
}
}
if (addrstr[0] == '\0') {
SLOGE("No IFA_ADDRESS in %s\n", msgtype);
return false;
}
return true;
}
/*
* Parse an binary message from a NETLINK_ROUTE netlink socket.
*/
bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
const struct nlmsghdr *nh;
for (nh = (struct nlmsghdr *) buffer;
NLMSG_OK(nh, size) && (nh->nlmsg_type != NLMSG_DONE);
nh = NLMSG_NEXT(nh, size)) {
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("interface");
break;
}
rta = RTA_NEXT(rta, len);
}
} 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;
} 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;
}
} else {
SLOGD("Unexpected netlink message. type=0x%x\n", nh->nlmsg_type);
}
}
return true;
}
/* If the string between 'str' and 'end' begins with 'prefixlen' characters
* from the 'prefix' array, then return 'str + prefixlen', otherwise return
* NULL.
*/
static const char*
has_prefix(const char* str, const char* end, const char* prefix, size_t prefixlen)
{
if ((end-str) >= (ptrdiff_t)prefixlen && !memcmp(str, prefix, prefixlen))
return str + prefixlen;
else
return NULL;
}
/* Same as strlen(x) for constant string literals ONLY */
#define CONST_STRLEN(x) (sizeof(x)-1)
/* Convenience macro to call has_prefix with a constant string literal */
#define HAS_CONST_PREFIX(str,end,prefix) has_prefix((str),(end),prefix,CONST_STRLEN(prefix))
/*
* Parse an ASCII-formatted message from a NETLINK_KOBJECT_UEVENT
* netlink socket.
*/
bool NetlinkEvent::parseAsciiNetlinkMessage(char *buffer, int size) {
const char *s = buffer;
const char *end;
int param_idx = 0;
int i;
int first = 1;
if (size == 0)
return false;
/* Ensure the buffer is zero-terminated, the code below depends on this */
buffer[size-1] = '\0';
end = s + size;
while (s < end) {
if (first) {
const char *p;
/* buffer is 0-terminated, no need to check p < end */
for (p = s; *p != '@'; p++) {
if (!*p) { /* no '@', should not happen */
return false;
}
}
mPath = strdup(p+1);
first = 0;
} else {
const char* a;
if ((a = HAS_CONST_PREFIX(s, end, "ACTION=")) != NULL) {
if (!strcmp(a, "add"))
mAction = NlActionAdd;
else if (!strcmp(a, "remove"))
mAction = NlActionRemove;
else if (!strcmp(a, "change"))
mAction = NlActionChange;
} else if ((a = HAS_CONST_PREFIX(s, end, "SEQNUM=")) != NULL) {
mSeq = atoi(a);
} else if ((a = HAS_CONST_PREFIX(s, end, "SUBSYSTEM=")) != NULL) {
mSubsystem = strdup(a);
} else if (param_idx < NL_PARAMS_MAX) {
mParams[param_idx++] = strdup(s);
}
}
s += strlen(s) + 1;
}
return true;
}
bool NetlinkEvent::decode(char *buffer, int size, int format) {
if (format == NetlinkListener::NETLINK_FORMAT_BINARY) {
return parseBinaryNetlinkMessage(buffer, size);
} else {
return parseAsciiNetlinkMessage(buffer, size);
}
}
const char *NetlinkEvent::findParam(const char *paramName) {
size_t len = strlen(paramName);
for (int i = 0; i < NL_PARAMS_MAX && mParams[i] != NULL; ++i) {
const char *ptr = mParams[i] + len;
if (!strncmp(mParams[i], paramName, len) && *ptr == '=')
return ++ptr;
}
SLOGE("NetlinkEvent::FindParam(): Parameter '%s' not found", paramName);
return NULL;
}
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