228 lines
6.9 KiB
C++
228 lines
6.9 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <stdlib.h>
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#include <string.h>
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#define LOG_TAG "NetlinkEvent"
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#include <cutils/log.h>
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#include <sysutils/NetlinkEvent.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <linux/if.h>
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter_ipv4/ipt_ULOG.h>
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/* From kernel's net/netfilter/xt_quota2.c */
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const int QLOG_NL_EVENT = 112;
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#include <linux/netlink.h>
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#include <linux/rtnetlink.h>
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const int NetlinkEvent::NlActionUnknown = 0;
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const int NetlinkEvent::NlActionAdd = 1;
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const int NetlinkEvent::NlActionRemove = 2;
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const int NetlinkEvent::NlActionChange = 3;
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const int NetlinkEvent::NlActionLinkUp = 4;
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const int NetlinkEvent::NlActionLinkDown = 5;
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NetlinkEvent::NetlinkEvent() {
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mAction = NlActionUnknown;
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memset(mParams, 0, sizeof(mParams));
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mPath = NULL;
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mSubsystem = NULL;
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}
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NetlinkEvent::~NetlinkEvent() {
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int i;
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if (mPath)
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free(mPath);
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if (mSubsystem)
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free(mSubsystem);
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for (i = 0; i < NL_PARAMS_MAX; i++) {
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if (!mParams[i])
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break;
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free(mParams[i]);
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}
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}
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void NetlinkEvent::dump() {
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int i;
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for (i = 0; i < NL_PARAMS_MAX; i++) {
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if (!mParams[i])
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break;
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SLOGD("NL param '%s'\n", mParams[i]);
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}
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}
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/*
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* Parse an binary message from a NETLINK_ROUTE netlink socket.
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*/
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bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
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size_t sz = size;
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const struct nlmsghdr *nh = (struct nlmsghdr *) buffer;
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while (NLMSG_OK(nh, sz) && (nh->nlmsg_type != NLMSG_DONE)) {
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if (nh->nlmsg_type == RTM_NEWLINK) {
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int len = nh->nlmsg_len - sizeof(*nh);
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struct ifinfomsg *ifi;
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if (sizeof(*ifi) > (size_t) len) {
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SLOGE("Got a short RTM_NEWLINK message\n");
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continue;
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}
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ifi = (ifinfomsg *)NLMSG_DATA(nh);
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if ((ifi->ifi_flags & IFF_LOOPBACK) != 0) {
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continue;
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}
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struct rtattr *rta = (struct rtattr *)
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((char *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
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len = NLMSG_PAYLOAD(nh, sizeof(*ifi));
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while(RTA_OK(rta, len)) {
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switch(rta->rta_type) {
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case IFLA_IFNAME:
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char buffer[16 + IFNAMSIZ];
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snprintf(buffer, sizeof(buffer), "INTERFACE=%s",
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(char *) RTA_DATA(rta));
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mParams[0] = strdup(buffer);
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mAction = (ifi->ifi_flags & IFF_LOWER_UP) ?
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NlActionLinkUp : NlActionLinkDown;
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mSubsystem = strdup("net");
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break;
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}
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rta = RTA_NEXT(rta, len);
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}
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} else if (nh->nlmsg_type == QLOG_NL_EVENT) {
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char *devname;
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ulog_packet_msg_t *pm;
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size_t len = nh->nlmsg_len - sizeof(*nh);
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if (sizeof(*pm) > len) {
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SLOGE("Got a short QLOG message\n");
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continue;
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}
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pm = (ulog_packet_msg_t *)NLMSG_DATA(nh);
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devname = pm->indev_name[0] ? pm->indev_name : pm->outdev_name;
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asprintf(&mParams[0], "ALERT_NAME=%s", pm->prefix);
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asprintf(&mParams[1], "INTERFACE=%s", devname);
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mSubsystem = strdup("qlog");
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mAction = NlActionChange;
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} else {
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SLOGD("Unexpected netlink message. type=0x%x\n", nh->nlmsg_type);
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}
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nh = NLMSG_NEXT(nh, size);
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}
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return true;
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}
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/* If the string between 'str' and 'end' begins with 'prefixlen' characters
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* from the 'prefix' array, then return 'str + prefixlen', otherwise return
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* NULL.
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*/
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static const char*
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has_prefix(const char* str, const char* end, const char* prefix, size_t prefixlen)
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{
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if ((end-str) >= (ptrdiff_t)prefixlen && !memcmp(str, prefix, prefixlen))
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return str + prefixlen;
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else
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return NULL;
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}
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/* Same as strlen(x) for constant string literals ONLY */
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#define CONST_STRLEN(x) (sizeof(x)-1)
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/* Convenience macro to call has_prefix with a constant string literal */
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#define HAS_CONST_PREFIX(str,end,prefix) has_prefix((str),(end),prefix,CONST_STRLEN(prefix))
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/*
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* Parse an ASCII-formatted message from a NETLINK_KOBJECT_UEVENT
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* netlink socket.
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*/
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bool NetlinkEvent::parseAsciiNetlinkMessage(char *buffer, int size) {
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const char *s = buffer;
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const char *end;
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int param_idx = 0;
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int i;
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int first = 1;
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if (size == 0)
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return false;
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/* Ensure the buffer is zero-terminated, the code below depends on this */
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buffer[size-1] = '\0';
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end = s + size;
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while (s < end) {
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if (first) {
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const char *p;
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/* buffer is 0-terminated, no need to check p < end */
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for (p = s; *p != '@'; p++) {
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if (!*p) { /* no '@', should not happen */
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return false;
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}
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}
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mPath = strdup(p+1);
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first = 0;
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} else {
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const char* a;
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if ((a = HAS_CONST_PREFIX(s, end, "ACTION=")) != NULL) {
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if (!strcmp(a, "add"))
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mAction = NlActionAdd;
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else if (!strcmp(a, "remove"))
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mAction = NlActionRemove;
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else if (!strcmp(a, "change"))
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mAction = NlActionChange;
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} else if ((a = HAS_CONST_PREFIX(s, end, "SEQNUM=")) != NULL) {
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mSeq = atoi(a);
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} else if ((a = HAS_CONST_PREFIX(s, end, "SUBSYSTEM=")) != NULL) {
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mSubsystem = strdup(a);
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} else if (param_idx < NL_PARAMS_MAX) {
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mParams[param_idx++] = strdup(s);
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}
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}
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s += strlen(s) + 1;
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}
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return true;
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}
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bool NetlinkEvent::decode(char *buffer, int size, int format) {
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if (format == NetlinkListener::NETLINK_FORMAT_BINARY) {
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return parseBinaryNetlinkMessage(buffer, size);
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} else {
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return parseAsciiNetlinkMessage(buffer, size);
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}
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}
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const char *NetlinkEvent::findParam(const char *paramName) {
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size_t len = strlen(paramName);
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for (int i = 0; i < NL_PARAMS_MAX && mParams[i] != NULL; ++i) {
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const char *ptr = mParams[i] + len;
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if (!strncmp(mParams[i], paramName, len) && *ptr == '=')
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return ++ptr;
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}
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SLOGE("NetlinkEvent::FindParam(): Parameter '%s' not found", paramName);
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return NULL;
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}
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